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Sample records for africa asia europa

  1. Europa

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This image of Jupiter's icy moon Europa, the first Europa image returned by New Horizons, was taken with the spacecraft's Long Range Reconnaissance Imager (LORRI) camera at 07:19 Universal Time on February 27, from a range of 3.1 million kilometers (1.9 million miles). The longitude of the disk center is 307 degrees West and the image scale is 15 kilometers (9 miles) per pixel. This is one of a series of images designed to look for landforms near Europa's terminator -- the line dividing day and night -- where low Sun angles highlight subtle topographic features.

    Europa's fractured icy surface is thought to overlie an ocean about 100 kilometers (60 miles) below the surface, and the New Horizons team will be analyzing these images for clues about the nature of the icy crust and the forces that have deformed it. Europa is about the size of Earth's moon, with a diameter of 3,130 kilometers (1.945 miles).

    This is one of a handful of images of the Jupiter system already returned by New Horizons during its close approach to Jupiter. Most of the data being gathered by the spacecraft are stored onboard and will be downlinked to Earth during March and April 2007.

  2. Estimating the burden of paratyphoid a in Asia and Africa.

    PubMed

    Arndt, Michael B; Mosites, Emily M; Tian, Mu; Forouzanfar, Mohammad H; Mokhdad, Ali H; Meller, Margaret; Ochiai, Rion L; Walson, Judd L

    2014-06-01

    Despite the increasing availability of typhoid vaccine in many regions, global estimates of mortality attributable to enteric fever appear stable. While both Salmonella enterica serovar Typhi (S. Typhi) and serovar Paratyphi (S. Paratyphi) cause enteric fever, limited data exist estimating the burden of S. Paratyphi, particularly in Asia and Africa. We performed a systematic review of both English and Chinese-language databases to estimate the regional burden of paratyphoid within Africa and Asia. Distinct from previous reviews of the topic, we have presented two separate measures of burden; both incidence and proportion of enteric fever attributable to paratyphoid. Included articles reported laboratory-confirmed Salmonella serovar classification, provided clear methods on sampling strategy, defined the age range of participants, and specified the time period of the study. A total of 64 full-text articles satisfied inclusion criteria and were included in the qualitative synthesis. Paratyphoid A was commonly identified as a cause of enteric fever throughout Asia. The highest incidence estimates in Asia came from China; four studies estimated incidence rates of over 150 cases/100,000 person-years. Paratyphoid A burden estimates from Africa were extremely limited and with the exception of Nigeria, few population or hospital-based studies from Africa reported significant Paratyphoid A burden. While significant gaps exist in the existing population-level estimates of paratyphoid burden in Asia and Africa, available data suggest that paratyphoid A is a significant cause of enteric fever in Asia. The high variability in documented incidence and proportion estimates of paratyphoid suggest considerable geospatial variability in the burden of paratyphoid fever. Additional efforts to monitor enteric fever at the population level will be necessary in order to accurately quantify the public health threat posed by S. Paratyphi A, and to improve the prevention and treatment of

  3. Estimating the Burden of Paratyphoid A in Asia and Africa

    PubMed Central

    Arndt, Michael B.; Mosites, Emily M.; Tian, Mu; Forouzanfar, Mohammad H.; Mokhdad, Ali H.; Meller, Margaret; Ochiai, Rion L.; Walson, Judd L.

    2014-01-01

    Despite the increasing availability of typhoid vaccine in many regions, global estimates of mortality attributable to enteric fever appear stable. While both Salmonella enterica serovar Typhi (S. Typhi) and serovar Paratyphi (S. Paratyphi) cause enteric fever, limited data exist estimating the burden of S. Paratyphi, particularly in Asia and Africa. We performed a systematic review of both English and Chinese-language databases to estimate the regional burden of paratyphoid within Africa and Asia. Distinct from previous reviews of the topic, we have presented two separate measures of burden; both incidence and proportion of enteric fever attributable to paratyphoid. Included articles reported laboratory-confirmed Salmonella serovar classification, provided clear methods on sampling strategy, defined the age range of participants, and specified the time period of the study. A total of 64 full-text articles satisfied inclusion criteria and were included in the qualitative synthesis. Paratyphoid A was commonly identified as a cause of enteric fever throughout Asia. The highest incidence estimates in Asia came from China; four studies estimated incidence rates of over 150 cases/100,000 person-years. Paratyphoid A burden estimates from Africa were extremely limited and with the exception of Nigeria, few population or hospital-based studies from Africa reported significant Paratyphoid A burden. While significant gaps exist in the existing population-level estimates of paratyphoid burden in Asia and Africa, available data suggest that paratyphoid A is a significant cause of enteric fever in Asia. The high variability in documented incidence and proportion estimates of paratyphoid suggest considerable geospatial variability in the burden of paratyphoid fever. Additional efforts to monitor enteric fever at the population level will be necessary in order to accurately quantify the public health threat posed by S. Paratyphi A, and to improve the prevention and treatment of

  4. Directory of Engineering Education Institutions: Africa, Asia, Latin America.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    This directory presents data on 458 degree-awarding engineering education institutions in countries in Africa, Asia, and Latin America. Data include the general educational pattern of the country and specific institutional information such as: structure, staff, enrollment, research, specializations offered, address, academic period, admissions…

  5. Africa, Asia, Europe, and Latin America.

    ERIC Educational Resources Information Center

    Loh, Eudora I.

    1992-01-01

    This annotated bibliography lists 30 government documents published between 1988 and 1991 by Argentina, Bolivia, Brazil, Burundi, Chile, China, Columbia, Denmark, France, Gambia, Guinea Bissau, Hong Kong, India, Italy, Luxembourg, Mexico, Nepal, Nigeria, Portugal, Rwanda, South Africa, and Thailand. Topics addressed include the environment,…

  6. Africa, Asia, Europe, and Latin America.

    ERIC Educational Resources Information Center

    Loh, Eudora I.

    1994-01-01

    Annotates 25 publications from 19 countries: Bolivia, Brazil, Cape Verde, Chile, Dominican Republic, Hungary, India, Ireland, Jamaica, Malaysia, Mexico, Morocco, Mozambique, Netherlands, Niger, Nigeria, Peru, South Africa, and Venezuela. Topics include the environment, women's role, and household consumption and expenditures. The publication of an…

  7. Global warming threatens agricultural productivity in Africa and South Asia

    NASA Astrophysics Data System (ADS)

    Sultan, Benjamin

    2012-12-01

    The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC; Christensen et al 2007) has, with greater confidence than previous reports, warned the international community that the increase in anthropogenic greenhouse gases emissions will result in global climate change. One of the most direct and threatening impacts it may have on human societies is the potential consequences on global crop production. Indeed agriculture is considered as the most weather-dependent of all human activities (Hansen 2002) since climate is a primary determinant for agricultural productivity. The potential impact of climate change on crop productivity is an additional strain on the global food system which is already facing the difficult challenge of increasing food production to feed a projected 9 billion people by 2050 with changing consumption patterns and growing scarcity of water and land (Beddington 2010). In some regions such as Sub-Saharan Africa or South Asia that are already food insecure and where most of the population increase and economic development will take place, climate change could be the additional stress that pushes systems over the edge. A striking example, if needed, is the work from Collomb (1999) which estimates that by 2050 food needs will more than quintuple in Africa and more than double in Asia. Better knowledge of climate change impacts on crop productivity in those vulnerable regions is crucial to inform policies and to support adaptation strategies that may counteract the adverse effects. Although there is a growing literature on the impact of climate change on crop productivity in tropical regions, it is difficult to provide a consistent assessment of future yield changes because of large uncertainties in regional climate change projections, in the response of crops to environmental change (rainfall, temperature, CO2 concentration), in the coupling between climate models and crop productivity functions, and in the adaptation of

  8. Hepatitis B epidemiology in Asia, the Middle East and Africa.

    PubMed

    André, F

    2000-02-18

    Asia and Africa have previously been classified as areas of high endemicity for hepatitis B virus (HBV), but in some countries highly effective vaccination programmes have shifted this pattern towards intermediate or low endemicity. Thus, China is now the only country in Asia where HBV endemicity is high. Countries with intermediate endemicity include India, Korea, the Philippines, Taiwan and Thailand, and those with low endemicity include Japan, Pakistan, Bangladesh, Singapore, Sri Lanka and Malaysia. Most countries in Africa have high HBV endemicity, with the exceptions of Tunisia and Morocco, which have intermediate endemicity. Zambia has borderline intermediate/high endemicity. In the Middle East, Bahrain, Iran, Israel and Kuwait are areas of low endemicity, Cyprus, Iraq and the United Arab Emirates have intermediate endemicity, and Egypt, Jordan, Oman, Palestine, Yemen and Saudi Arabia have high endemicity. All of these Middle East countries reach a large proportion of their population with hepatitis B vaccination, which is reducing the infection rate, particularly in Saudi Arabia. The vaccination programme in Taiwan has also greatly reduced the HBV infection rate. Future vaccination programmes must take into account the mode of transmission of HBV, the healthcare infrastructure to deliver vaccination, and the socioeconomic and political factors in each individual country, to determine the most cost-effective way of infection control. PMID:10683538

  9. China-Africa and China-Asia Collaboration on Schistosomiasis Control: A SWOT Analysis.

    PubMed

    Xu, J; Bergquist, R; Qian, Y-J; Wang, Q; Yu, Q; Peeling, R; Croft, S; Guo, J-G; Zhou, X-N

    2016-01-01

    Schistosomiasis, a disease caused by a trematode, parasitic worm, is a worldwide public health problem. In spite of great progress with regard to morbidity control, even elimination of this infection in recent decades, there are still challenges to overcome in sub-Saharan Africa and endemic areas in Southeast Asia. Regarded as one of the most successful countries with respect to schistosomiasis control, The People's Republic of China has accumulated considerable experience and learnt important lessons in various local settings that could benefit schistosomiasis control in other endemic countries. Based on an analysis of conceived strengths, weaknesses, opportunities and threats (SWOT) of potential collaborative activities with regard to schistosomiasis in Africa and Asia, this article addresses the importance of collaborative efforts and explores the priorities that would be expected to facilitate the transfer of Chinese experience to low- and middle-income countries in Africa and Asia. PMID:27137455

  10. Challenging Educational Injustice: "Grassroots" Privatisation in South Asia and Sub-Saharan Africa

    ERIC Educational Resources Information Center

    Tooley, James

    2013-01-01

    The phenomenon of low-cost private schools "mushrooming" in poor areas of sub-Saharan Africa and South Asia, and elsewhere, is now well-documented. Findings from research by the author's teams and others show that these schools are serving a majority (urban and peri-urban) or significant minority (rural) of the poor, including…

  11. Perceived Professional Development Needs of English-Speaking Evangelical Academic Deans in Africa and Asia

    ERIC Educational Resources Information Center

    Crawford, Leslie J.

    2013-01-01

    This study identified the perceived professional development needs of English-speaking evangelical theological school deans in Africa and Asia, as a basis for evaluating or creating professional development programs for these regions. It answered the question: What are the perceptions of the need for professional development prior to and after…

  12. Monitoring the Quality of Medicines: Results from Africa, Asia, and South America

    PubMed Central

    Hajjou, Mustapha; Krech, Laura; Lane-Barlow, Christi; Roth, Lukas; Pribluda, Victor S.; Phanouvong, Souly; El-Hadri, Latifa; Evans, Lawrence; Raymond, Christopher; Yuan, Elaine; Siv, Lang; Vuong, Tuan-Anh; Boateng, Kwasi Poku; Okafor, Regina; Chibwe, Kennedy M.; Lukulay, Patrick H.

    2015-01-01

    Monitoring the quality of medicines plays a crucial role in an integrated medicines quality assurance system. In a publicly available medicines quality database (MQDB), the U.S. Pharmacopeial Convention (USP) reports results of data collected from medicines quality monitoring (MQM) activities spanning the period of 2003–2013 in 17 countries of Africa, Asia, and South America. The MQDB contains information on 15,063 samples collected and tested using Minilab® screening methods and/or pharmacopeial methods. Approximately 71% of the samples reported came from Asia, 23% from Africa, and 6% from South America. The samples collected and tested include mainly antibiotic, antimalarial, and antituberculosis medicines. A total of 848 samples, representing 5.6% of total samples, failed the quality test. The failure proportion per region was 11.5%, 10.4%, and 2.9% for South America, Africa, and Asia, respectively. Eighty-one counterfeit medicines were reported, 86.4% of which were found in Asia and 13.6% in Africa. Additional analysis of the data shows the distribution of poor-quality medicines per region and by therapeutic indication as well as possible trends of counterfeit medicines. PMID:25897073

  13. Analysis of Genetic Diversity and Population Structure of Sesame Accessions from Africa and Asia as Major Centers of Its Cultivation.

    PubMed

    Dossa, Komivi; Wei, Xin; Zhang, Yanxin; Fonceka, Daniel; Yang, Wenjuan; Diouf, Diaga; Liao, Boshou; Cissé, Ndiaga; Zhang, Xiurong

    2016-01-01

    Sesame is an important oil crop widely cultivated in Africa and Asia. Understanding the genetic diversity of accessions from these continents is critical to designing breeding methods and for additional collection of sesame germplasm. To determine the genetic diversity in relation to geographical regions, 96 sesame accessions collected from 22 countries distributed over six geographic regions in Africa and Asia were genotyped using 33 polymorphic SSR markers. Large genetic variability was found within the germplasm collection. The total number of alleles was 137, averaging 4.15 alleles per locus. The accessions from Asia displayed more diversity than those from Africa. Accessions from Southern Asia (SAs), Eastern Asia (EAs), and Western Africa (WAf) were highly diversified, while those from Western Asia (WAs), Northern Africa (NAf), and Southeastern Africa (SAf) had the lowest diversity. The analysis of molecular variance revealed that more than 44% of the genetic variance was due to diversity among geographic regions. Five subpopulations, including three in Asia and two in Africa, were cross-identified through phylogenetic, PCA, and STRUCTURE analyses. Most accessions clustered in the same population based on their geographical origins. Our results provide technical guidance for efficient management of sesame genetic resources in breeding programs and further collection of sesame germplasm from these different regions. PMID:27077887

  14. Analysis of Genetic Diversity and Population Structure of Sesame Accessions from Africa and Asia as Major Centers of Its Cultivation

    PubMed Central

    Dossa, Komivi; Wei, Xin; Zhang, Yanxin; Fonceka, Daniel; Yang, Wenjuan; Diouf, Diaga; Liao, Boshou; Cissé, Ndiaga; Zhang, Xiurong

    2016-01-01

    Sesame is an important oil crop widely cultivated in Africa and Asia. Understanding the genetic diversity of accessions from these continents is critical to designing breeding methods and for additional collection of sesame germplasm. To determine the genetic diversity in relation to geographical regions, 96 sesame accessions collected from 22 countries distributed over six geographic regions in Africa and Asia were genotyped using 33 polymorphic SSR markers. Large genetic variability was found within the germplasm collection. The total number of alleles was 137, averaging 4.15 alleles per locus. The accessions from Asia displayed more diversity than those from Africa. Accessions from Southern Asia (SAs), Eastern Asia (EAs), and Western Africa (WAf) were highly diversified, while those from Western Asia (WAs), Northern Africa (NAf), and Southeastern Africa (SAf) had the lowest diversity. The analysis of molecular variance revealed that more than 44% of the genetic variance was due to diversity among geographic regions. Five subpopulations, including three in Asia and two in Africa, were cross-identified through phylogenetic, PCA, and STRUCTURE analyses. Most accessions clustered in the same population based on their geographical origins. Our results provide technical guidance for efficient management of sesame genetic resources in breeding programs and further collection of sesame germplasm from these different regions. PMID:27077887

  15. Geomorphology and Geodynamics at Crustal Boundaries within Asia and Africa

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The release of SRTM images by NASA over the past two years year has been greeted by foreign Earth scientist's as "NASA's gift to the World". The goodwill that this has engendered in parts of Africa. India, Pakistan and Bangladesh, as scientists in those countries contemplated what many of them considered an unprovoked and unjustifiable US invasion of Iraq, cannot be underestimated. We have used SRTM images from Africa and India and elsewhere to examine aspects of tectonism, geodynamics and tsunami and earthquake hazards. Highlights of this research are itemized in this final report. One difficulty that has arisen is , of course, that the funding for the science lead the availability of the data by more than a year. and as a result many of the findings are as yet unpublished.

  16. AgMIP: New Results from Sub-Saharan Africa and South Asia Regional Integrated Assessments

    NASA Astrophysics Data System (ADS)

    Rosenzweig, C.

    2014-12-01

    AgMIP conducted the first set of comprehensive regional integrated assessments of climate change impacts on smallholder farmers in Sub-Saharan Africa and South Asia led by researchers from the regions themselves. The project developed new methods integrating climate, crop, livestock and economic models to conduct climate change impact assessments that characterize impacts on smallholder groups. AgMIP projections of climate change impacts on agriculture are more realistic than previous assessments because they take agricultural development into account. Using the best available data and models, the assessments directly evaluated yield, income, and poverty outcomes including the effects of adaptation packages and development pathways. Results show that even with agricultural development, climate change generally will exert negative pressure on yields of smallholder farmers in Sub-Saharan Africa and South Asia. Without adaptation, climate change leads to increased poverty in some locations in Sub-Saharan Africa and South Asia compared to a future in which climate change does not occur. Adaptation can significantly improve smallholder farmer responses to climate change. AgMIP expert teams identified improved varieties, sowing practices, fertilizer application, and irrigation applications as prioritized adaptation strategies. These targeted adaptation packages were able to overcome a portion of detrimental impacts but could not compensate completely in many locations. Even in cases where average impact is near zero, vulnerability (i.e., those at risk of loss) can be substantial even when mean impacts are positive.

  17. Climate change impacts on crop productivity in Africa and South Asia

    NASA Astrophysics Data System (ADS)

    Knox, Jerry; Hess, Tim; Daccache, Andre; Wheeler, Tim

    2012-09-01

    Climate change is a serious threat to crop productivity in regions that are already food insecure. We assessed the projected impacts of climate change on the yield of eight major crops in Africa and South Asia using a systematic review and meta-analysis of data in 52 original publications from an initial screen of 1144 studies. Here we show that the projected mean change in yield of all crops is - 8% by the 2050s in both regions. Across Africa, mean yield changes of - 17% (wheat), - 5% (maize), - 15% (sorghum) and - 10% (millet) and across South Asia of - 16% (maize) and - 11% (sorghum) were estimated. No mean change in yield was detected for rice. The limited number of studies identified for cassava, sugarcane and yams precluded any opportunity to conduct a meta-analysis for these crops. Variation about the projected mean yield change for all crops was smaller in studies that used an ensemble of > 3 climate (GCM) models. Conversely, complex simulation studies that used biophysical crop models showed the greatest variation in mean yield changes. Evidence of crop yield impact in Africa and South Asia is robust for wheat, maize, sorghum and millet, and either inconclusive, absent or contradictory for rice, cassava and sugarcane.

  18. Diarrhea and respiratory symptoms among travelers to Asia, Africa, and South and Central America from Scotland.

    PubMed

    Redman, Christopher Allan; Maclennan, Alice; Wilson, Eleanor; Walker, Eric

    2006-01-01

    Surveillance using admissions to hospital, while being useful, is a poor indicator of the real incidence of disease encountered by travelers. An alternative is self-reported illness among those who attended at a pretravel clinic prior to their travels. Estimates of incidence and risk factors were determined for attendees at a travel clinic in Scotland using a questionnaire. Analysis for risk factors was carried out for those travelers visiting countries in Africa, Asia, or South and Central America, who had traveled for 1 week or more and had returned between 1997 and 2001 (N= 4,856). Multivariate logistic regression was used to test the hypotheses that time abroad and age-group would be significant for both respiratory and diarrheal symptoms regardless of which of the three geographical areas are visited. From 2006 returned questionnaires (response rate = 41.3%), diarrhea and respiratory symptoms were reported by 44.2 and 16.8% of respondents, respectively; the incidence was significantly greater among travelers to Asia for both diarrheal (55.5%) and respiratory (23.7%) symptoms than among travelers to Africa (36.6 and 12.2%, respectively) or South and Central America (39.5 and 16.2%, respectively). For diarrhea, age was a highly significant risk factor for travelers to Asia, South and Central America, and Africa. Being a self-organized tourist/backpacker, traveling to Asia was associated with increased risk, while for Africa and South and Central America visiting family or friends was associated with a lower risk. For travelers to Asia, traveling to the Indian subcontinent was significantly associated with increased risk. The majority of travelers had an adverse event while traveling abroad, with diarrhea and respiratory conditions being especially common despite attending a travel clinic for advice prior to departure. However, the limitations of this surveillance-based strategy have highlighted the requirement for more research to understand more fully the

  19. World Directory of Energy Information. Volume 2: Middle East, Africa and Asia/Pacific

    SciTech Connect

    Not Available

    1982-01-01

    Volume 2 of the four-part Directory includes a detailed review of energy resource development of 64 countries, 15 of which are in the Middle East, 30 in Africa, and 19 in the Asia and Pacific area. The volume is divided into four parts: (1) International Framework; (2) Country Reviews; (3) Energy Organizations; and (4) Energy Publications. The organizations and publications information covers both international and by country. Three indices list publications alphabetically, by subject and country, and publishing bodies. 6 figures, 2 tables. (DCK)

  20. Phylogenetic relationship of Hepatozoon blood parasites found in snakes from Africa, America and Asia.

    PubMed

    Haklová, B; Majláthová, V; Majláth, I; Harris, D J; Petrilla, V; Litschka-Koen, T; Oros, M; Peťko, B

    2014-03-01

    The blood parasites from the genus Hepatozoon Miller, 1908 (Apicomplexa: Adeleida: Hepatozoidae) represent the most common intracellular protozoan parasites found in snakes. In the present study, we examined 209 individuals of snakes, from different zoogeographical regions (Africa, America, Asia and Europe), for the occurrence of blood parasites using both molecular and microscopic examination methods, and assess phylogenetic relationships of all Hepatozoon parasites from snakes for the first time. In total, 178 blood smears obtained from 209 individuals, representing 40 species, were examined, from which Hepatozoon unicellular parasites were found in 26 samples (14·6% prevalence). Out of 180 samples tested by molecular method polymerase chain reaction (PCR), the presence of parasites was observed in 21 individuals (prevalence 11·6%): 14 snakes from Africa belonging to six genera (Dendroaspis, Dispholidus, Mehelya, Naja, Philothamnus and Python), five snakes from Asia from the genus Morelia and two snakes from America, from two genera (Coluber and Corallus). The intensity of infection varied from one to 1433 infected cells per 10 000 erythrocytes. Results of phylogenetic analyses (Bayesian and Maximum Likelihood) revealed the existence of five haplotypes divided into four main lineages. The present data also indicate neither geographical pattern of studied Hepatozoon sp., nor congruency in the host association. PMID:24553081

  1. Abrupt post-glacial climate events in West Asia and North Africa monsoon domains

    NASA Astrophysics Data System (ADS)

    Gasse, Françoise; Van Campo, Elise

    1994-09-01

    Regions beyond the present or past penetration of the Indian and African monsoons have experienced several large and abrupt climatic fluctuations over the past 13 14C kyr. Pollen and lake records from West Asia (Western Tibet and Rajasthan), East Africa (Ethiopia) and West Africa (Western Sahara, Sahel and subequatorial Africa) were selected on the basis of chronological control, sensitivity of both site and environmental indicators to climate change, the continuity of the record, and interdisciplinary control of the palaeoclimatic interpretation. Conditions wetter than those of today prevailed during the early-mid-Holocene period, but major dry spells are recorded at all sites during the intervals ˜ 11.0-9.5 kyr BP, ˜ 8-7 kyr BP and 3-4 kyr BP. Several records also suggest dry events of minor amplitude around 6 kyr BP. Potential boundary forcings of insolation and sea surface and tropical land surface conditions are discussed. The solar radiation accounts for the general envelop of the post-glacial monsoon fluctuations, but explains neither the timing nor the amplitude of the short-term changes. In spite of apparent covariation between fluctuations in sea surface conditions in the North Atlantic and the monsoon record, no direct mechanism could be found relating the intensity of the oceanic thermohaline conveyor belt to the monsoon strength. Changes in tropical land surface conditions (soil moisture negative feedback, and changes in CH 4 production from wetlands) provide a more satisfactory hypothesis for explaining abrupt reversal events.

  2. Orientalism(s), World Geography Textbooks, and Temporal Paradox: Questioning Representations of Southwest Asia and North Africa

    ERIC Educational Resources Information Center

    Zagumny, Lisa; Richey, Amanda B.

    2013-01-01

    In this critical discourse analysis of six high-school world geography textbooks, we explore how constructions and representations of North Africa and Southwest Asia have served to reinforce Orientalist discourse in formal curriculum. Visual and written representations in these textbooks were overwhelmingly confounded by a traditional/modern…

  3. Quality of vaccination services and social demand for vaccinations in Africa and Asia.

    PubMed Central

    Streefland, P. H.; Chowdhury, A. M.; Ramos-Jimenez, P.

    1999-01-01

    For immunization to be effective in the long run as a major global disease control intervention it is important to provide good quality vaccination services. Studies carried out in three countries in Asia (Bangladesh, India, and the Philippines) and two countries in Africa (Ethiopia and Malawi), and reported on in this article, document the fact that parents are willing to invest considerable effort in having their children vaccinated; however, there are a number of serious shortcomings in the quality of the routine vaccination services and strains are apparent at the interface between the vaccination providers and the users. These shortcomings are detracting from the sustainability of routine vaccination programmes and are promoting the growth of pools of nonimmunized and partially immunized children. To safeguard the continued operation and to enhance the coverage of routine vaccination programmes it is crucial that these difficulties be addressed. PMID:10534895

  4. Testing baseline stability of some neutron monitors in Europe, Africa, and Asia

    NASA Astrophysics Data System (ADS)

    Ahluwalia, H. S.; Ygbuhay, R. C.

    2013-06-01

    For six decades, the global network of neutron monitors (NMs) has provided a continuous stream of very valuable data to the heliophysics community, leading to many insights into the myriad modes of charged particle transport in the tangled magnetic fields that permeate the 3D heliosphere. Earlier, Ahluwalia and Ygbuhay (2012) reported on the drifts in some high latitude NM counting rates in the American zone. We continue our enquiry by testing the stability of the counting rate baselines of some NMs operating in Europe, Africa, and Asia. The data from these detectors have been extremely valuable for the short-term time variation studies, but caution is advised in using the data for long-term studies from NMs with baselines that are drifting for cause(s) unknown.

  5. Analysis of human infectious avian influenza virus: hemagglutinin genetic characteristics in Asia and Africa from 2004 to 2009.

    PubMed

    Zhang, Jirong; Lei, Fumin

    2010-09-01

    In the present study, we used nucleotide and protein sequences of avian influenza virus H5N1, which were obtained in Asia and Africa, analyzed HA proteins using ClustalX1.83 and MEGA4.0, and built a genetic evolutionary tree of HA nucleotides. The analysis revealed that the receptor specificity amino acid of A/HK/213/2003, A/Turkey/65596/2006 and etc mutated into QNG, which could bind with á-2, 3 galactose and á-2, 6 galactose. A mutation might thus take place and lead to an outbreak of human infections of avian influenza virus. The mutations of HA protein amino acids from 2004 to 2009 coincided with human infections provided by the World Health Organization, indicating a "low-high-highest-high-low" pattern. We also found out that virus strains in Asia are from different origins: strains from Southeast Asia and East Asia are of the same origin, whereas those from West Asia, South Asia and Africa descend from one ancestor. The composition of the phylogenetic tree and mutations of key site amino acids in HA proteins reflected the fact that the majority of strains are regional and long term, and virus diffusions exist between China, Laos, Malaysia, Indonesia, Azerbaijan, Turkey and Iraq. We would advise that pertinent vaccines be developed and due attention be paid to the spread of viruses between neighboring countries and the dangers of virus mutation and evolution. PMID:21392344

  6. Ticks (Ixodidae) on birds migrating from Europe and Asia to Africa, 1959-61*

    PubMed Central

    Hoogstraal, Harry; Kaiser, Makram N.; Traylor, Melvin A.; Guindy, Ezzat; Gaber, Sobhy

    1963-01-01

    The need for imaginative thinking and research in the epidemiology of diseases transmitted by arthropods is made manifest by new views of the longevity and host ranges of arthropod-borne viruses, as well as by other biological and medical phenomena. Among these is the intercontinental transport of ticks by migrating birds. During the fall migration periods of 1959, 1960 and 1961, 32 086 birds (comprising 72 forms) were examined for ticks in Egypt while en route from Asia and eastern Europe to tropical Africa. Of these, 40 forms, represented by 31 434 birds, were tick-infested. The bird hosts, numbering 1040 (3.31% of the tick-infested bird forms examined), bore 1761 ticks, or 1.69 ticks per host. Common ticks taken were Hyalomma m. marginatum, Haemaphysalis punctata, and Ixodes ricinus. Ixodes frontalis and Hyalomma aegyptium were less common and Haemaphysalis sulcata, H. otophila, and H. pavlovskyi were rare. The common tick species are known to be reservoirs and vectors of pathogens causing a number of human and animal diseases in Europe and Asia. Several of the bird hosts have also been incriminated as reservoirs in their summer ranges. Over 20 strains of pathogenic viruses were isolated from these birds and their ticks in Egypt in the 1961 fall migration period. The most difficult problems in investigations such as this in many parts of the world are taxonomic ones: the correct identification of bird hosts, of immature stages of ticks and of viruses. PMID:13961632

  7. The Plasmodium vivax in China: decreased in local cases but increased imported cases from Southeast Asia and Africa

    PubMed Central

    Feng, Jun; Xiao, Huihui; Zhang, Li; Yan, He; Feng, Xinyu; Fang, Wen; Xia, Zhigui

    2015-01-01

    Currently the local P. vivax was sharply decreased while the imported vivax malaria increased in China. Despite Southeast Asia was still the main import source of vivax malaria, the trend of Africa become serious, especially for west and central Africa. Herein we have clarified the trend of P. vivax in China from 2004–2012, and made some analysis for the differences of imported vivax back from different regions. There are significantly different of P. vivax between Southeast Asia and Africa, also the difference was observed for different regions in Africa. Additionally, we have explored the possibility for the difference of the P. vivax between migrant workers back from west and central Africa and the prevalence of local population. This reminds us that surveillance and training should be strengthened by medical staffs on the imported P. vivax cases reported especially from west and central Africa, in order to reduce the risk of malaria reintroduction and, specific tools should be developed, as well as the epidemiological study to avoid the misdiagnosis such as P. ovale and P. vivax. PMID:25739365

  8. Lead levels in new enamel household paints from Asia, Africa and South America.

    PubMed

    Clark, C Scott; Rampal, Krishna G; Thuppil, Venkatesh; Roda, Sandy M; Succop, Paul; Menrath, William; Chen, Chin K; Adebamowo, Eugenious O; Agbede, Oluwole A; Sridhar, Mynepalli K C; Adebamowo, Clement A; Zakaria, Yehia; El-Safty, Amal; Shinde, Rana M; Yu, Jiefei

    2009-10-01

    In 2006 a report on the analysis for lead in 80 new residential paints from four countries in Asia revealed high levels in three of the countries (China, India and Malaysia) and low levels in a fourth country (Singapore) where a lead in paint regulation was enforced. The authors warned of the possible export of lead-painted consumer products to the United States and other countries and the dangers the lead paint represented to children in the countries where it was available for purchase. The need for a worldwide ban on the use of lead in paints was emphasized to prevent an increase in exposure and disease from this very preventable environmental source. Since the earlier paper almost 300 additional new paint samples have been collected from the four initial countries plus 8 additional countries, three from Asia, three from Africa and two from South America. During the intervening time period two million toys and other items imported into the United States were recalled because the lead content exceeded the United States standard. High lead paints were detected in all 12 countries. The average lead concentration by country ranged from 6988 (Singapore) to 31,960ppm (Ecuador). One multinational company sold high lead paint in one country through January 2007 but sold low lead paint later in 2007 indicating that a major change to cease adding lead to their paints had occurred. However, the finding that almost one-third of the samples would meet the new United States standard for new paint of 90ppm, suggests that the technology is already available in at least 11 of the 12 countries to produce low lead enamel paints for domestic use. The need remains urgent to establish effective worldwide controls to prevent the needless poisoning of millions of children from this preventable exposure. PMID:19656507

  9. Phylogeographical Structure in Mitochondrial DNA of Legume Pod Borer (Maruca vitrata) Population in Tropical Asia and Sub-Saharan Africa

    PubMed Central

    Periasamy, Malini; Schafleitner, Roland; Muthukalingan, Krishnan; Ramasamy, Srinivasan

    2015-01-01

    This study was undertaken to assess the genetic diversity and host plant races of M. vitrata population in South and Southeast Asia and sub-Saharan Africa. The cytochrome c oxidase subunit 1 (cox1) gene was used to understand the phylogenetic relationship of geographically different M. vitrata population, but previous studies did not include population from Southeast Asia, the probable center of origin for Maruca, and from east Africa. Extensive sampling was done from different host plant species in target countries. Reference populations from Oceania and Latin America were used. An amplicon of 658 bp was produced by polymerase chain reaction, and 64 haplotypes were identified in 686 M. vitrata individuals. Phylogenetic analysis showed no difference among the M. vitrata population from different host plants. However, the results suggested that M. vitrata has formed two putative subspecies (which cannot be differentiated based on morphological characters) in Asia and sub-Saharan Africa, as indicated by the high pairwise FST values (0.44–0.85). The extremely high FST values (≥0.93) of Maruca population in Latin America and Oceania compared to Asian and African population seem to indicate a different species. On the continental or larger geographical region basis, the genetic differentiation is significantly correlated with the geographical distance. In addition, two putative species of Maruca, including M. vitrata occur in Australia, Indonesia and Papua New Guinea. The negative Tajima’s D and Fu’s FS values showed the recent demographic expansion of Maruca population. The haplotype network and Automatic Barcode Gap Discovery analyses confirmed the results of phylogenetic analysis. Thus, this study confirmed the presence of three putative Maruca species, including one in Latin America, one in Oceania (including Indonesia) and M. vitrata in Asia, Africa and Oceania. Hence, the genetic differences in Maruca population should be carefully considered while

  10. Mortality from external causes in Africa and Asia: evidence from INDEPTH Health and Demographic Surveillance System Sites

    PubMed Central

    Streatfield, P. Kim; Khan, Wasif A.; Bhuiya, Abbas; Hanifi, Syed M.A.; Alam, Nurul; Diboulo, Eric; Niamba, Louis; Sié, Ali; Lankoandé, Bruno; Millogo, Roch; Soura, Abdramane B.; Bonfoh, Bassirou; Kone, Siaka; Ngoran, Eliezer K.; Utzinger, Juerg; Ashebir, Yemane; Melaku, Yohannes A.; Weldearegawi, Berhe; Gomez, Pierre; Jasseh, Momodou; Azongo, Daniel; Oduro, Abraham; Wak, George; Wontuo, Peter; Attaa-Pomaa, Mary; Gyapong, Margaret; Manyeh, Alfred K.; Kant, Shashi; Misra, Puneet; Rai, Sanjay K.; Juvekar, Sanjay; Patil, Rutuja; Wahab, Abdul; Wilopo, Siswanto; Bauni, Evasius; Mochamah, George; Ndila, Carolyne; Williams, Thomas N.; Khaggayi, Christine; Nyaguara, Amek; Obor, David; Odhiambo, Frank O.; Ezeh, Alex; Oti, Samuel; Wamukoya, Marylene; Chihana, Menard; Crampin, Amelia; Collinson, Mark A.; Kabudula, Chodziwadziwa W.; Wagner, Ryan; Herbst, Kobus; Mossong, Joël; Emina, Jacques B.O.; Sankoh, Osman A.; Byass, Peter

    2014-01-01

    Background Mortality from external causes, of all kinds, is an important component of overall mortality on a global basis. However, these deaths, like others in Africa and Asia, are often not counted or documented on an individual basis. Overviews of the state of external cause mortality in Africa and Asia are therefore based on uncertain information. The INDEPTH Network maintains longitudinal surveillance, including cause of death, at population sites across Africa and Asia, which offers important opportunities to document external cause mortality at the population level across a range of settings. Objective To describe patterns of mortality from external causes at INDEPTH Network sites across Africa and Asia, according to the WHO 2012 verbal autopsy (VA) cause categories. Design All deaths at INDEPTH sites are routinely registered and followed up with VA interviews. For this study, VA archives were transformed into the WHO 2012 VA standard format and processed using the InterVA-4 model to assign cause of death. Routine surveillance data also provide person-time denominators for mortality rates. Results A total of 5,884 deaths due to external causes were documented over 11,828,253 person-years. Approximately one-quarter of those deaths were to children younger than 15 years. Causes of death were dominated by childhood drowning in Bangladesh, and by transport-related deaths and intentional injuries elsewhere. Detailed mortality rates are presented by cause of death, age group, and sex. Conclusions The patterns of external cause mortality found here generally corresponded with expectations and other sources of information, but they fill some important gaps in population-based mortality data. They provide an important source of information to inform potentially preventive intervention designs. PMID:25377327

  11. Muslim oil and gas periphery; the future of hydrocarbons in Africa, southeast Asia and the Caspian. Master`s thesis

    SciTech Connect

    Crockett, B.D.

    1997-12-01

    This thesis is a study of the contemporary political, economic, and technical developments and future prospects of the Muslim hydrocarbon exporters of Africa, Southeast Asia, and the Caspian. The established Muslim oil and gas periphery of Africa and Southeast Asia has four members in the Organization of Petroleum Exporting Countries (OPEC) and is systemically increasing its production of natural gas. I analyze US government and corporate policies regarding the countries and the major dilemmas of the Muslim hydrocarbon periphery. The first chapter provides a selective overview of global energy source statistics; the policies, disposition and composition of the major hydrocarbon production and consumption players and communities; a selective background of OPEC and its impact on the globe; and a general portrait of how the Muslim periphery piece fits into the overall Muslim oil and gas puzzle. Chapter two analyzes the established Muslim oil and gas periphery of Africa and Southeast Asia asking the following questions: What are the major political, economic, and technical trends and dilemmas affecting these producer nations. And what are the United States` policies and relationships with these producers. Chapter three asks the same questions as chapter two, but with regard to the newly independent states of the Caspian Sea. I probe the regional petroleum exploration and transportation dilemmas in some detail.

  12. Europa: Processes and Habitability

    NASA Technical Reports Server (NTRS)

    Pappalardo, Robert T.

    2006-01-01

    This viewgraph presentation reviews the known and possible geologic processes of Europa. It shows slides of Europa, with different terrains (ridged plains and molten plains), and a possible view of the interior. Europa's eccentric orbit is reviewed. The presentation also reviews Europa's composition. The possible reasons for Europa's geology are reviewed. Also the possiblity that life exists on Europa is raised. The planned Europa Geophysical Explorer mission is also reviewed.

  13. Rich nutrition from the poorest - cereal fermentations in Africa and Asia.

    PubMed

    Nout, M J Rob

    2009-10-01

    Cereal fermentations in Africa and Asia involve mainly the processing of maize, rice, sorghum and the millets. Lactic acid bacteria (Lactobacillus, Pediococcus), Enterobacter spp., yeasts (Candida, Debaryomyces, Endomycopsis, Hansenula, Pichia, Saccharomyces and Trichosporon spp.) and filamentous fungi (Amylomyces, Aspergillus, Mucor, and Rhizopus spp.) contribute to desirable modifications of taste, flavour, acidity, digestibility, and texture in non-alcoholic beverages (e.g., uji, and ben-saalga), porridges (e.g., mawè) and cooked gels (e.g., kenkey, idli, and mifen). In addition, alcoholic beverages (beers such as tchoukoutou and jnard; and spirits e.g. jiu) are obtained using malt, or using amylolytic mixed microbial starter cultures as generators of fermentable substrates. Wet processing, marketing of multi-purpose intermediate products, co-fermentation for texture and nutrition, and mixed culture fermentations as practiced in indigenous fermentation processes are of interest for industrial innovation and for better control of natural mixed culture fermentation systems. On the other hand, the nutritional properties of traditional cereal fermented products can be enhanced by increasing their nutrient and energy density, as well as by increasing their mineral status by combining mineral fortification and dephytinization. PMID:19747601

  14. Status analysis and strategic framework for sanitation management in Asia and Africa.

    PubMed

    Kim, Y K; Seo, I S; Jung, N C; Kim, J Y; Byun, J H

    2007-01-01

    Following rapid population increase and industrial development, the ever increasing environmental pollution and the associated sanitation-related problem are no longer regional or local but have become an issue requiring global-dimensional concern and the provision of problem-solving alternatives. Especially, since most problems result from inappropriate sewerage and the lack of sewage treatment system are in a serious state occurring in economically underdeveloped regions, and as such, their significance is enormous. The United Nations Environment Programme (UNEP) has been making efforts to establish the technology selection methodology applicable in developing countries, through the accurate status, investigation and analysis of the wastewater management state in Asian and African regions, and the sanitation management guideline utilisable by political leaders or decision-makers. As part of this effort, the Korea Institute of Water Environment (KIWE), together with the UNEP, selected China and Vietnam (in Asia) and Kenya and Ethiopia (in Africa) as subject countries to investigate and perform on-site sanitation management investigations and analysis in this research. Results obtained from the on-site investigation were analysed, and in order to be helpful in establishing a strategy for sanitation management in underdeveloped countries, the strategic framework (SF) has been made based on characterised results. PMID:17881834

  15. Integrated Pest Management for Sustainable Intensification of Agriculture in Asia and Africa

    PubMed Central

    Pretty, Jules; Pervez Bharucha, Zareen

    2015-01-01

    Integrated Pest Management (IPM) is a leading complement and alternative to synthetic pesticides and a form of sustainable intensification with particular importance for tropical smallholders. Global pesticide use has grown over the past 20 years to 3.5 billion kg/year, amounting to a global market worth $45 billion. The external costs of pesticides are $4–$19 (€3–15) per kg of active ingredient applied, suggesting that IPM approaches that result in lower pesticide use will benefit, not only farmers, but also wider environments and human health. Evidence for IPM’s impacts on pesticide use and yields remains patchy. We contribute an evaluation using data from 85 IPM projects from 24 countries of Asia and Africa implemented over the past twenty years. Analysing outcomes on productivity and reliance on pesticides, we find a mean yield increase across projects and crops of 40.9% (SD 72.3), combined with a decline in pesticide use to 30.7% (SD 34.9) compared with baseline. A total of 35 of 115 (30%) crop combinations resulted in a transition to zero pesticide use. We assess successes in four types of IPM projects, and find that at least 50% of pesticide use is not needed in most agroecosystems. Nonetheless, policy support for IPM is relatively rare, counter-interventions from pesticide industry common, and the IPM challenge never done as pests, diseases and weeds evolve and move. PMID:26463073

  16. Genetically Engineered Crops and Certified Organic Agriculture for Improving Nutrition Security in Africa and South Asia.

    PubMed

    Pray, Carl; Ledermann, Samuel

    2016-01-01

    In Africa and South Asia, where nutrition insecurity is severe, two of the most prominent production technologies are genetically modified (GM) crops and certified organic agriculture. We analyze the potential impact pathways from agricultural production to nutrition. Our review of data and the literature reveals increasing farm-level income from cash crop production as the main pathway by which organic agriculture and GM agriculture improve nutrition. Potential secondary pathways include reduced prices of important food crops like maize due to GM maize production and increased food production using organic technology. Potential tertiary pathways are improvements in health due to reduced insecticide use. Challenges to the technologies achieving their impact include the politics of GM agriculture and the certification costs of organic agriculture. Given the importance of agricultural production in addressing nutrition security, accentuated by the post-2015 sustainable development agenda, the chapter concludes by stressing the importance of private and public sector research in improving the productivity and adoption of both GM and organic crops. In addition, the chapter reminds readers that increased farm income and productivity require complementary investments in health, education, food access and women's empowerment to actually improve nutrition security. PMID:27197837

  17. Moving towards universal health coverage: health insurance reforms in nine developing countries in Africa and Asia.

    PubMed

    Lagomarsino, Gina; Garabrant, Alice; Adyas, Atikah; Muga, Richard; Otoo, Nathaniel

    2012-09-01

    We analyse nine low-income and lower-middle-income countries in Africa and Asia that have implemented national health insurance reforms designed to move towards universal health coverage. Using the functions-of-health-systems framework, we describe these countries' approaches to raising prepaid revenues, pooling risk, and purchasing services. Then, using the coverage-box framework, we assess their progress across three dimensions of coverage: who, what services, and what proportion of health costs are covered. We identify some patterns in the structure of these countries' reforms, such as use of tax revenues to subsidise target populations, steps towards broader risk pools, and emphasis on purchasing services through demand-side financing mechanisms. However, none of the reforms purely conform to common health-system archetypes, nor are they identical to each other. We report some trends in these countries' progress towards universal coverage, such as increasing enrolment in government health insurance, a movement towards expanded benefits packages, and decreasing out-of-pocket spending accompanied by increasing government share of spending on health. Common, comparable indicators of progress towards universal coverage are needed to enable countries undergoing reforms to assess outcomes and make midcourse corrections in policy and implementation. PMID:22959390

  18. Fine Particulate Pollution and Source Apportionment in the Urban Centers for Africa, Asia and Latin America

    NASA Astrophysics Data System (ADS)

    Guttikunda, S. K.; Johnson, T. M.; Procee, P.

    2004-12-01

    Fossil fuel combustion for domestic cooking and heating, power generation, industrial processes, and motor vehicles are the primary sources of air pollution in the developing country cities. Over the past twenty years, major advances have been made in understanding the social and economic consequences of air pollution. In both industrialized and developing countries, it has been shown that air pollution from energy combustion has detrimental impacts on human health and the environment. Lack of information on the sectoral contributions to air pollution - especially fine particulates, is one of the typical constraints for an effective integrated urban air quality management program. Without such information, it is difficult, if not impossible, for decision makers to provide policy advice and make informed investment decisions related to air quality improvements in developing countries. This also raises the need for low-cost ways of determining the principal sources of fine PM for a proper planning and decision making. The project objective is to develop and verify a methodology to assess and monitor the sources of PM, using a combination of ground-based monitoring and source apportionment techniques. This presentation will focus on four general tasks: (1) Review of the science and current activities in the combined use of monitoring data and modeling for better understanding of PM pollution. (2) Review of recent advances in atmospheric source apportionment techniques (e.g., principal component analysis, organic markers, source-receptor modeling techniques). (3) Develop a general methodology to use integrated top-down and bottom-up datasets. (4) Review of a series of current case studies from Africa, Asia and Latin America and the methodologies applied to assess the air pollution and its sources.

  19. Positive approaches to education for sexual health with examples from Asia and Africa.

    PubMed

    Senanayake, P

    1992-07-01

    Some approaches to health education are presented based on experiences in Asia and Africa. Consideration in project design should be given to methodology, location, timing, and target group. There is no one correct approach. Qualitative evaluations are possible. Outreach to a larger population such as the out-of-school unemployed is an important goal, as well as directing Family Life Education (FLE) to the primary school level, when children are still in school. Sexual health is defined as state of physical and psychological well being including sexuality. FLE is a culturally sensitive approach to sexual health education. The avoidance of sexual terms promotes acceptance in countries such as Sri Lanka. The problem of sexuality and adolescence and the current protracted period is that adults view this period as an inconvenience rather than an inevitability. The needs of youth need to be recognized in spite of the resistance some cultures may feel about sex education encouraging promiscuity. The example is given of the government of Mali, which in conjunction with the International Planned Parenthood Federation, trained 150 workers to mobilize youth and introduce them to FLE. The prerequisite is mental preparation of the adult population through training programs. An example of an effective method of role play presentation by youth of major youth issues was used in creating a positive feeling for youth among World Health Assembly delegates, who are Ministers of Health and Senior Government Health Officials. The Youth Counseling Services and Family Education Project in Ethiopia is described. It was a youth-designed and youth-implemented project which took into consideration working hours, staff attitude, and hospitality toward youths. Other methods described are: 1) drama, 2) songs, 3) role play, 4) literature, 5) videos and film shows, 6) radio, and 7) telephone. Integration of FLE can be positive when it is combined with youth centers, income-generation projects

  20. Migrations of European honey bee lineages into Africa, Asia, and North America during the Oligocene and Miocene

    NASA Astrophysics Data System (ADS)

    Kotthoff, Ulrich; Wappler, Torsten; Engel, Michael

    2013-04-01

    Today honey bees, principally the western honey bee, Apis mellifera, represent a multi-billion dollar agricultural industry. Through the efforts of humans they have become established well outside of their modern native ranges, having been introduced multiple times into the Americas, Australia, New Zealand, New Caledonia, and many areas of Oceania. The native, i.e., non-human influenced, distribution and migration of honey bee species and populations has been a matter of serious and continued debate. Apicultural dogma informs us that the center of origin of honey bees (genus Apis) resides in Asia, with subsequent migration and diversification into Europe and Asia. Recent population genetic studies of the western honey bee, Apis mellifera, slightly modified this received wisdom by suggesting that this species originated in Africa and subsequently reinvaded Eurasia. Research into the historical biogeography of honey bees has ignored entirely the abundant fossil evidence distributed through a variety of Late Paleogene (Oligocene) and Early Neogene (Miocene) deposits, a diversity which is predominantly European in origin, particularly among the most basal species of the genus. We have examined the morphological disparity and affinities of the full living and fossil diversity of honey bees ranging from their earliest origins to the present day. This analysis indicates that honey bees exhibited a greater morphological disparity during the Oligocene and Miocene epochs, a time when the principal lineages were established, and that Apis apparently originated in Europe, spreading from there into Asia, Africa, and North America, with subsequent diversification in the former two regions and extinction in the latter. During the human migrations and colonization honey bees were once again introduced multiple times into the Americas, as well as into Australia and Asia.

  1. Videos Bridging Asia and Africa: Overcoming Cultural and Institutional Barriers in Technology-Mediated Rural Learning

    ERIC Educational Resources Information Center

    Van Mele, Paul; Wanvoeke, Jonas; Akakpo, Cyriaque; Dacko, Rosaline Maiga; Ceesay, Mustapha; Beavogui, Louis; Soumah, Malick; Anyang, Robert

    2010-01-01

    Will African farmers watch and learn from videos featuring farmers in Bangladesh? Learning videos on rice seed management were made with rural women in Bangladesh. By using a new approach, called zooming-in, zooming-out, the videos were of regional relevance and locally appropriate. When the Africa Rice Center (AfricaRice) introduced them to…

  2. QTL for yield and associated traits in the Seri/Babax population grown across several environments in Mexico, in the West Asia, North Africa, and South Asia regions.

    PubMed

    Lopes, Marta S; Reynolds, Matthew P; McIntyre, C Lynne; Mathews, Ky L; Jalal Kamali, M R; Mossad, Moussa; Feltaous, Yousef; Tahir, Izzat S A; Chatrath, Ravish; Ogbonnaya, Francis; Baum, Michael

    2013-04-01

    Heat and drought adaptive quantitative trait loci (QTL) in a spring bread wheat population resulting from the Seri/Babax cross designed to minimize confounding agronomic traits have been identified previously in trials conducted in Mexico. The same population was grown across a wide range of environments where heat and drought stress are naturally experienced including environments in Mexico, West Asia, North Africa (WANA), and South Asia regions. A molecular genetic linkage map including 475 marker loci associated to 29 linkage groups was used for QTL analysis of yield, days to heading (DH) and to maturity (DM), grain number (GM2), thousand kernel weight (TKW), plant height (PH), canopy temperature at the vegetative and grain filling stages (CTvg and CTgf), and early ground cover. A QTL for yield on chromosome 4A was confirmed across several environments, in subsets of lines with uniform allelic expression of a major phenology QTL, but not independently from PH. With terminal stress, TKW QTL was linked or pleiotropic to DH and DM. The link between phenology and TKW suggested that early maturity would favor the post-anthesis grain growth periods resulting in increased grain size and yields under terminal stress. GM2 and TKW were partially associated with markers at different positions suggesting different genetic regulation and room for improvement of both traits. Prediction accuracy of yield was improved by 5 % when using marker scores of component traits (GM2 and DH) together with yield in multiple regression. This procedure may provide accumulation of more favorable alleles during selection. PMID:23269228

  3. IFLA General Conference, 1992. Division of Regional Activities: Section on Africa; Section on Asia/Oceania; Section on Latin America and the Caribbean. Papers.

    ERIC Educational Resources Information Center

    International Federation of Library Associations and Institutions, London (England).

    Seven papers delivered at the 1992 International Federation of Library Associations and Institutions annual meeting relating to regional activities are presented. These papers deal with library issues in Africa, Asia and Oceania, Latin America, and the Caribbean. The papers are: (1) "Designing National Information Policies in African: Process and…

  4. Large-scale transcriptome analysis in chickpea (Cicer arietinum L.), an orphan legume crop of the semi-arid tropics of Asia and Africa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chickpea (Cicer arietinum L.) is an important legume crop in the semi-arid regions of Asia and Africa. Gains in crop productivity have been low however, particularly due to biotic and abiotic stresses. To help enhance crop productivity using molecular breeding techniques, next generation sequencing ...

  5. Perceptions of the Host Country's Food Culture among Female Immigrants from Africa and Asia: Aspects Relevant for Cultural Sensitivity in Nutrition Communication

    ERIC Educational Resources Information Center

    Garnweidner, Lisa Maria; Terragni, Laura; Pettersen, Kjell Sverre; Mosdol, Annhild

    2012-01-01

    Objective: To explore how female immigrants from Africa and Asia perceive the host country's food culture, to identify aspects of their original food culture they considered important to preserve, and to describe how they go about preserving them. Design: Qualitative in-depth interviews. Setting: Oslo, Norway. Participants: Twenty one female…

  6. Artemisinin-resistant Plasmodium falciparum clinical isolates can infect diverse mosquito vectors of Southeast Asia and Africa

    PubMed Central

    St. Laurent, Brandyce; Miller, Becky; Burton, Timothy A.; Amaratunga, Chanaki; Men, Sary; Sovannaroth, Siv; Fay, Michael P.; Miotto, Olivo; Gwadz, Robert W.; Anderson, Jennifer M.; Fairhurst, Rick M.

    2015-01-01

    Artemisinin-resistant Plasmodium falciparum parasites are rapidly spreading in Southeast Asia, yet nothing is known about their transmission. This knowledge gap and the possibility that these parasites will spread to Africa endanger global efforts to eliminate malaria. Here we produce gametocytes from parasite clinical isolates that displayed artemisinin resistance in patients and in vitro, and use them to infect native and non-native mosquito vectors. We show that contemporary artemisinin-resistant isolates from Cambodia develop and produce sporozoites in two Southeast Asian vectors, Anopheles dirus and Anopheles minimus, and the major African vector, Anopheles coluzzii (formerly Anopheles gambiae M). The ability of artemisinin-resistant parasites to infect such highly diverse Anopheles species, combined with their higher gametocyte prevalence in patients, may explain the rapid expansion of these parasites in Cambodia and neighbouring countries, and further compromise efforts to prevent their global spread. PMID:26485448

  7. Artemisinin-resistant Plasmodium falciparum clinical isolates can infect diverse mosquito vectors of Southeast Asia and Africa.

    PubMed

    St Laurent, Brandyce; Miller, Becky; Burton, Timothy A; Amaratunga, Chanaki; Men, Sary; Sovannaroth, Siv; Fay, Michael P; Miotto, Olivo; Gwadz, Robert W; Anderson, Jennifer M; Fairhurst, Rick M

    2015-01-01

    Artemisinin-resistant Plasmodium falciparum parasites are rapidly spreading in Southeast Asia, yet nothing is known about their transmission. This knowledge gap and the possibility that these parasites will spread to Africa endanger global efforts to eliminate malaria. Here we produce gametocytes from parasite clinical isolates that displayed artemisinin resistance in patients and in vitro, and use them to infect native and non-native mosquito vectors. We show that contemporary artemisinin-resistant isolates from Cambodia develop and produce sporozoites in two Southeast Asian vectors, Anopheles dirus and Anopheles minimus, and the major African vector, Anopheles coluzzii (formerly Anopheles gambiae M). The ability of artemisinin-resistant parasites to infect such highly diverse Anopheles species, combined with their higher gametocyte prevalence in patients, may explain the rapid expansion of these parasites in Cambodia and neighbouring countries, and further compromise efforts to prevent their global spread. PMID:26485448

  8. Alternative medicines for AIDS in resource-poor settings: insights from exploratory anthropological studies in Asia and Africa.

    PubMed

    Hardon, Anita; Desclaux, Alice; Egrot, Marc; Simon, Emmanuelle; Micollier, Evelyne; Kyakuwa, Margaret

    2008-01-01

    The emergence of alternative medicines for AIDS in Asia and Africa was discussed at a satellite symposium and the parallel session on alternative and traditional treatments of the AIDSImpact meeting, held in Marseille, in July 2007. These medicines are heterogeneous, both in their presentation and in their geographic and cultural origin. The sessions focused on the role of these medications in selected resource poor settings in Africa and Asia now that access to anti-retroviral therapy is increasing. The aims of the sessions were to (1) identify the actors involved in the diffusion of these alternative medicines for HIV/AIDS, (2) explore uses and forms, and the way these medicines are given legitimacy, (3) reflect on underlying processes of globalisation and cultural differentiation, and (4) define priority questions for future research in this area. This article presents the insights generated at the meeting, illustrated with some findings from the case studies (Uganda, Senegal, Benin, Burkina Faso, China and Indonesia) that were presented. These case studies reveal the wide range of actors who are involved in the marketing and supply of alternative medicines. Regulatory mechanisms are weak. The efficacy claims of alternative medicines often reinforce a biomedical paradigm for HIV/AIDS, and fit with a healthy living ideology promoted by AIDS care programs and support groups. The AIDSImpact session concluded that more interdisciplinary research is needed on the experience of people living with HIV/AIDS with these alternative medicines, and on the ways in which these products interact (or not) with anti-retroviral therapy at pharmacological as well as psychosocial levels. PMID:18616794

  9. Identifying important breast cancer control strategies in Asia, Latin America and the Middle East/North Africa

    PubMed Central

    2011-01-01

    Background Breast cancer is the most frequent cause of cancer death in women worldwide, but global disparities in breast cancer control persist, due to a lack of a comprehensive breast cancer control strategy in many countries. Objectives To identify and compare the need for breast cancer control strategies in Asia, Latin America and the Middle East/North Africa and to develop a common framework to guide the development of national breast cancer control strategies. Methods Data were derived from open-ended, semi-structured interviews conducted in 2007 with 221 clinicians, policy makers, and patient advocates; stratified across Asia (n = 97), Latin America (n = 46), the Middle East/North Africa (ME/NA) (n = 39) and Australia and Canada (n = 39). Respondents were identified using purposive and snowballing sampling. Interpretation of the data utilized interpretive phenomenological analysis where transcripts and field notes were coded and analyzed and common themes were identified. Analysis of regional variation was conducted based on the frequency of discussion and the writing of the manuscript followed the RATS guidelines. Results Analysis revealed four major themes that form the foundation for developing national breast cancer control strategies: 1) building capacity; 2) developing evidence; 3) removing barriers; and 4) promoting advocacy - each specified across five sub-ordinate dimensions. The propensity to discuss most dimensions was similar across regions, but managing advocacy was discussed more frequently (p = 0.004) and organized advocacy was discussed less frequently (p < 0.001) in Australia and Canada. Conclusions This unique research identified common themes for the development of breast cancer control strategies, grounded in the experience of local practitioners, policy makers and advocacy leaders across diverse regions. Future research should be aimed at gathering a wider array of experiences, including those of patients. PMID:21933435

  10. Pregnancy-related mortality in Africa and Asia: evidence from INDEPTH Health and Demographic Surveillance System sites

    PubMed Central

    Streatfield, P. Kim; Alam, Nurul; Compaoré, Yacouba; Rossier, Clementine; Soura, Abdramane B.; Bonfoh, Bassirou; Jaeger, Fabienne; Ngoran, Eliezer K.; Utzinger, Juerg; Gomez, Pierre; Jasseh, Momodou; Ansah, Akosua; Debpuur, Cornelius; Oduro, Abraham; Williams, John; Addei, Sheila; Gyapong, Margaret; Kukula, Vida A.; Bauni, Evasius; Mochamah, George; Ndila, Carolyne; Williams, Thomas N.; Desai, Meghna; Moige, Hellen; Odhiambo, Frank O.; Ogwang, Sheila; Beguy, Donatien; Ezeh, Alex; Oti, Samuel; Chihana, Menard; Crampin, Amelia; Price, Alison; Delaunay, Valérie; Diallo, Aldiouma; Douillot, Laetitia; Sokhna, Cheikh; Collinson, Mark A.; Kahn, Kathleen; Tollman, Stephen M.; Herbst, Kobus; Mossong, Joël; Emina, Jacques B.O.; Sankoh, Osman A.; Byass, Peter

    2014-01-01

    Background Women continue to die in unacceptably large numbers around the world as a result of pregnancy, particularly in sub-Saharan Africa and Asia. Part of the problem is a lack of accurate, population-based information characterising the issues and informing solutions. Population surveillance sites, such as those operated within the INDEPTH Network, have the potential to contribute to bridging the information gaps. Objective To describe patterns of pregnancy-related mortality at INDEPTH Network Health and Demographic Surveillance System sites in sub-Saharan Africa and southeast Asia in terms of maternal mortality ratio (MMR) and cause-specific mortality rates. Design Data on individual deaths among women of reproductive age (WRA) (15–49) resident in INDEPTH sites were collated into a standardised database using the INDEPTH 2013 population standard, the WHO 2012 verbal autopsy (VA) standard, and the InterVA model for assigning cause of death. Results These analyses are based on reports from 14 INDEPTH sites, covering 14,198 deaths among WRA over 2,595,605 person-years observed. MMRs varied between 128 and 461 per 100,000 live births, while maternal mortality rates ranged from 0.11 to 0.74 per 1,000 person-years. Detailed rates per cause are tabulated, including analyses of direct maternal, indirect maternal, and incidental pregnancy-related deaths across the 14 sites. Conclusions As expected, these findings confirmed unacceptably high continuing levels of maternal mortality. However, they also demonstrate the effectiveness of INDEPTH sites and of the VA methods applied to arrive at measurements of maternal mortality that are essential for planning effective solutions and monitoring programmatic impacts. PMID:25377328

  11. Systematics and biogeography of the Hylarana frog (Anura: Ranidae) radiation across tropical Australasia, Southeast Asia, and Africa.

    PubMed

    Oliver, Lauren A; Prendini, Elizabeth; Kraus, Fred; Raxworthy, Christopher J

    2015-09-01

    We present an inclusive molecular phylogeny for Hylarana across its global distribution, utilizing two mitochondrial and four nuclear gene regions for 69 of the 97 currently described species. We use phylogenetic methods to test monophyly of Hylarana, determine relationships among ten putative subgenera, identify major clades, reconstruct biogeographic history, and estimate continental dispersal dates. Results support Hylarana as a monophyletic group originating approximately 26.9MYA and comprising eight clades that partly correspond to currently described subgenera plus two new groups. The African and Australasian species each form clades embedded within a paraphyletic Southeast Asian group. We estimate that Africa and Australasia were colonized by Hylarana s.l. from SE Asia approximately 18.7 and 10.8MYA, respectively. Biogeographic reconstructions also support three separate colonization events in India from Southeast Asia. Examination of museum specimens identified morphological characters useful for delineating subgenera and species. We herein elevate all supported subgenera to genus rank and formally describe two new genera to produce a revised taxonomy congruent with our new phylogenetic and biogeographic findings. PMID:25987527

  12. An Andean ice-core record of a Middle Holocene mega-drought in North Africa and Asia

    NASA Astrophysics Data System (ADS)

    Davis, Mary E.; Thompson, Lonnie G.

    An ice core from the Nevado Huascarán col in the Cordillera Blanca of northern Peru contains high-resolution time series of dust concentrations and size distributions since the end of the last glacial stage. A large dust peak, dated ˜4500 years ago, is contemporaneous with a widespread and prolonged drought that apparently extended from North Africa to eastern China, evidence of which occurs in historical, archeological and paleoclimatic records. This event may have been associated with several centuries of weak Asian/Indian/African monsoons, possibly linked with a protracted cooling in the North Atlantic. During the second half of the 20th century, high austral-summer dust concentrations in the Huascarán record are significantly correlated with atmospheric conditions, such as sea-level pressure and zonal wind velocities that are consistent with El Niño-Southern Oscillation (ENSO) and positive North Atlantic Oscillation (NAO) indices, and with aridity in North Africa, southwest Asia and the Middle East. Therefore, the dominant submicron fraction of the dust may have been transported by more intense northeasterly trade winds from the African dry regions across the tropical Atlantic during a period of frequent and/or intense ENSO activity. The proposed ENSO conditions that may have been linked with drought in the monsoon region may also have contributed to aridity in tropical South America, including the Cordillera Blanca.

  13. A GCM investigation of dust aerosol impact on the regional climate of North Africa and South/East Asia

    NASA Astrophysics Data System (ADS)

    Gu, Y.; Xue, Y.; De Sales, F.; Liou, K. N.

    2016-04-01

    The climatic effects of dust aerosols in North Africa and South/East Asia have been investigated using an atmospheric general circulation model, NCEP/GCM/SSiB (Simplified Simple Biosphere Model) and the three-dimensional aerosol data simulated by the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model. GCM simulations show that due to the scattering and absorption of solar radiation by dust particles, surface temperature decreases over both regions, accompanied by a reduced sensible heat flux. However, precipitation responses are different in these two regions. Due to differences in dust location and the associated heating with respect to the rainfall band and circulation, the effect of dust could either enhance or suppress precipitation. Over the North Africa region where dust particles are mainly located to the north of rainfall band, heating of the air column by dust particles forces a stronger ascent motion over dust layers, which induces an anomalous subsidence (or a weakened upward motion) and suppressed cyclonic circulation to its south where precipitation reduces. Furthermore, both humidity and cloud decrease due to the heating in the middle troposphere (semi-direct effect). In South/East Asia, dust particles are located in the upper troposphere over the major rainfall band during the monsoon season, especially Southwest India and the coastal area of Bay of Bengal. Heating of the air column increases upward motion and strengthens cyclonic circulation. Humidity also increases due to the draw-in of the low level moist air. Therefore, cloud and precipitation increase over South/East Asia associated with dust effect. During the pre-monsoon season, when dust particles are located to the north of the monsoon rainfall band, the heating effect results in shifting precipitation northward. The heating of air column due to dust particles, not surface cooling, plays the major role in precipitation changes. The anomalous upward motion over dust regions will

  14. CD4+ T cell recovery during suppression of HIV replication: an international comparison of the immunological efficacy of antiretroviral therapy in North America, Asia and Africa

    PubMed Central

    Geng, Elvin H; Neilands, Torsten B; Thièbaut, Rodolphe; Bosco Bwana, Mwebesa; Nash, Denis; Moore, Richard D; Wood, Robin; Marcel Zannou, Djimon; Althoff, Keri N; Lian Lim, Poh; Nachega, Jean B; Easterbrook, Philippa J; Kambugu, Andrew; Little, Francesca; Nakigozi, Gertrude; Nakanjako, Damalie; Kiggundu, Valerian; Chung Ki Li, Patrick; Bangsberg, David R; Fox, Matthew P; Prozesky, Hans W; Hunt, Peter W; Davies, Mary-Ann; Reynolds, Steven J; Egger, Matthias; Yiannoutsos, Constantin T; Vittinghoff, Eric V; Deeks, Steven G; Martin, Jeffrey N

    2015-01-01

    Background: Even among HIV-infected patients who fully suppress plasma HIV RNA replication on antiretroviral therapy, genetic (e.g. CCL3L1 copy number), viral (e.g. tropism) and environmental (e.g. chronic exposure to microbial antigens) factors influence CD4 recovery. These factors differ markedly around the world and therefore the expected CD4 recovery during HIV RNA suppression may differ globally. Methods: We evaluated HIV-infected adults from North America, West Africa, East Africa, Southern Africa and Asia starting non-nucleoside reverse transcriptase inhibitor-based regimens containing efavirenz or nevirapine, who achieved at least one HIV RNA level <500/µl in the first year of therapy and observed CD4 changes during HIV RNA suppression. We used a piecewise linear regression to estimate the influence of region of residence on CD4 recovery, adjusting for socio-demographic and clinical characteristics. We observed 28 217 patients from 105 cohorts over 37 825 person-years. Results: After adjustment, patients from East Africa showed diminished CD4 recovery as compared with other regions. Three years after antiretroviral therapy initiation, the mean CD4 count for a prototypical patient with a pre-therapy CD4 count of 150/µl was 529/µl [95% confidence interval (CI): 517–541] in North America, 494/µl (95% CI: 429–559) in West Africa, 515/µl (95% CI: 508–522) in Southern Africa, 503/µl (95% CI: 478–528) in Asia and 437/µl (95% CI: 425–449) in East Africa. Conclusions: CD4 recovery during HIV RNA suppression is diminished in East Africa as compared with other regions of the world, and observed differences are large enough to potentially influence clinical outcomes. Epidemiological analyses on a global scale can identify macroscopic effects unobservable at the clinical, national or individual regional level. PMID:25859596

  15. Capacity building and predictors of success for HIV-1 drug resistance testing in the Asia-Pacific region and Africa

    PubMed Central

    Land, Sally; Zhou, Julian; Cunningham, Philip; Sohn, Annette H; Singtoroj, Thida; Katzenstein, David; Mann, Marita; Sayer, David; Kantor, Rami

    2013-01-01

    Background The TREAT Asia Quality Assessment Scheme (TAQAS) was developed as a quality assessment programme through expert education and training, for laboratories in the Asia-Pacific and Africa that perform HIV drug-resistance (HIVDR) genotyping. We evaluated the programme performance and factors associated with high-quality HIVDR genotyping. Methods Laboratories used their standard protocols to test panels of human immunodeficiency virus (HIV)-positive plasma samples or electropherograms. Protocols were documented and performance was evaluated according to a newly developed scoring system, agreement with panel-specific consensus sequence, and detection of drug-resistance mutations (DRMs) and mixtures of wild-type and resistant virus (mixtures). High-quality performance was defined as detection of ≥95% DRMs. Results Over 4.5 years, 23 participating laboratories in 13 countries tested 45 samples (30 HIV-1 subtype B; 15 non-B subtypes) in nine panels. Median detection of DRMs was 88–98% in plasma panels and 90–97% in electropherogram panels. Laboratories were supported to amend and improve their test outcomes as appropriate. Three laboratories that detected <80% DRMs in early panels demonstrated subsequent improvement. Sample complexity factors – number of DRMs (p<0.001) and number of DRMs as mixtures (p<0.001); and laboratory performance factors – detection of mixtures (p<0.001) and agreement with consensus sequence (p<0.001), were associated with high performance; sample format (plasma or electropherogram), subtype and genotyping protocol were not. Conclusion High-quality HIVDR genotyping was achieved in the TAQAS collaborative laboratory network. Sample complexity and detection of mixtures were associated with performance quality. Laboratories conducting HIVDR genotyping are encouraged to participate in quality assessment programmes. PMID:23845227

  16. High level of molecular and phenotypic biodiversity in Jatropha curcas from Central America compared to Africa, Asia and South America

    PubMed Central

    2014-01-01

    Background The main bottleneck to elevate jatropha (Jatropha curcas L.) from a wild species to a profitable biodiesel crop is the low genetic and phenotypic variation found in different regions of the world, hampering efficient plant breeding for productivity traits. In this study, 182 accessions from Asia (91), Africa (35), South America (9) and Central America (47) were evaluated at genetic and phenotypic level to find genetic variation and important traits for oilseed production. Results Genetic variation was assessed with SSR (Simple Sequence Repeat), TRAP (Target Region Amplification Polymorphism) and AFLP (Amplified fragment length polymorphism) techniques. Phenotypic variation included seed morphological characteristics, seed oil content and fatty acid composition and early growth traits. Jaccard’s similarity and cluster analysis by UPGM (Unweighted Paired Group Method) with arithmetic mean and PCA (Principle Component Analysis) indicated higher variability in Central American accessions compared to Asian, African and South American accessions. Polymorphism Information Content (PIC) values ranged from 0 to 0.65. In the set of Central American accessions. PIC values were higher than in other regions. Accessions from the Central American population contain alleles that were not found in the accessions from other populations. Analysis of Molecular Variance (AMOVA; P < 0.0001) indicated high genetic variation within regions (81.7%) and low variation across regions (18.3%). A high level of genetic variation was found on early growth traits and on components of the relative growth rate (specific leaf area, leaf weight, leaf weight ratio and net assimilation rate) as indicated by significant differences between accessions and by the high heritability values (50–88%). The fatty acid composition of jatropha oil significantly differed (P < 0.05) between regions. Conclusions The pool of Central American accessions showed very large genetic variation as

  17. Chlamydia trachomatis Infection in Pregnancy: The Global Challenge of Preventing Adverse Pregnancy and Infant Outcomes in Sub-Saharan Africa and Asia.

    PubMed

    Adachi, Kristina; Nielsen-Saines, Karin; Klausner, Jeffrey D

    2016-01-01

    Screening and treatment of sexually transmitted infections (STIs) in pregnancy represents an overlooked opportunity to improve the health outcomes of women and infants worldwide. Although Chlamydia trachomatis is the most common treatable bacterial STI, few countries have routine pregnancy screening and treatment programs. We reviewed the current literature surrounding Chlamydia trachomatis in pregnancy, particularly focusing on countries in sub-Saharan Africa and Asia. We discuss possible chlamydial adverse pregnancy and infant health outcomes (miscarriage, stillbirth, ectopic pregnancy, preterm birth, neonatal conjunctivitis, neonatal pneumonia, and other potential effects including HIV perinatal transmission) and review studies of chlamydial screening and treatment in pregnancy, while simultaneously highlighting research from resource-limited countries in sub-Saharan Africa and Asia. PMID:27144177

  18. Chlamydia trachomatis Infection in Pregnancy: The Global Challenge of Preventing Adverse Pregnancy and Infant Outcomes in Sub-Saharan Africa and Asia

    PubMed Central

    Adachi, Kristina; Nielsen-Saines, Karin

    2016-01-01

    Screening and treatment of sexually transmitted infections (STIs) in pregnancy represents an overlooked opportunity to improve the health outcomes of women and infants worldwide. Although Chlamydia trachomatis is the most common treatable bacterial STI, few countries have routine pregnancy screening and treatment programs. We reviewed the current literature surrounding Chlamydia trachomatis in pregnancy, particularly focusing on countries in sub-Saharan Africa and Asia. We discuss possible chlamydial adverse pregnancy and infant health outcomes (miscarriage, stillbirth, ectopic pregnancy, preterm birth, neonatal conjunctivitis, neonatal pneumonia, and other potential effects including HIV perinatal transmission) and review studies of chlamydial screening and treatment in pregnancy, while simultaneously highlighting research from resource-limited countries in sub-Saharan Africa and Asia. PMID:27144177

  19. Modeling Europa's dust plumes

    NASA Astrophysics Data System (ADS)

    Southworth, B. S.; Kempf, S.; Schmidt, J.

    2015-12-01

    The discovery of Jupiter's moon Europa maintaining a probably sporadic water vapor plume constitutes a huge scientific opportunity for NASA's upcoming mission to this Galilean moon. Measuring properties of material emerging from interior sources offers a unique chance to understand conditions at Europa's subsurface ocean. Exploiting results obtained for the Enceladus plume, we simulate possible Europa plume configurations, analyze particle number density and surface deposition results, and estimate the expected flux of ice grains on a spacecraft. Due to Europa's high escape speed, observing an active plume will require low-altitude flybys, preferably at altitudes of 5-100 km. At higher altitudes a plume may escape detection. Our simulations provide an extensive library documenting the possible structure of Europa dust plumes, which can be quickly refined as more data on Europa dust plumes are collected.

  20. Comparison of resistance to third-generation cephalosporins in Shigella between Europe-America and Asia-Africa from 1998 to 2012.

    PubMed

    Gu, B; Zhou, M; Ke, X; Pan, S; Cao, Y; Huang, Y; Zhuang, L; Liu, G; Tong, M

    2015-10-01

    We conducted a systematic review to compare resistance to third-generation cephalosporins (TGCs) in Shigella strains between Europe-America and Asia-Africa from 1998 to 2012 based on a literature search of computerized databases. In Asia-Africa, the prevalence of resistance of total and different subtypes to ceftriaxone, cefotaxime and ceftazidime increased markedly, with a total prevalence of resistance up to 14·2% [95% confidence interval (CI) 3·9-29·4], 22·6% (95% CI 4·8-48·6) and 6·2% (95% CI 3·8-9·1) during 2010-2012, respectively. By contrast, resistance rates to these TGCs in Europe-America remained relatively low--less than 1·0% during the 15 years. A noticeable finding was that certain countries both in Europe-America and Asia-Africa, had a rapid rising trend in the prevalence of resistance of S. sonnei, which even outnumbered S. flexneri in some periods. Moreover, comparison between countries showed that currently the most serious problem concerning resistance to these TGCs appeared in Vietnam, especially for ceftriaxone, China, especially for cefotaxime and Iran, especially for ceftazidime. These data suggest that monitoring of the drug resistance of Shigella strains should be strengthened and that rational use of antibiotics is required. PMID:25553947

  1. Population frequencies of the Triallelic 5HTTLPR in six Ethnicially diverse samples from North America, Southeast Asia, and Africa.

    PubMed

    Haberstick, Brett C; Smolen, Andrew; Williams, Redford B; Bishop, George D; Foshee, Vangie A; Thornberry, Terence P; Conger, Rand; Siegler, Ilene C; Zhang, Xiaodong; Boardman, Jason D; Frajzyngier, Zygmunt; Stallings, Michael C; Brent Donnellan, M; Halpern, Carolyn T; Harris, Kathleen Mullan

    2015-03-01

    Genetic differences between populations are potentially an important contributor to health disparities around the globe. As differences in gene frequencies influence study design, it is important to have a thorough understanding of the natural variation of the genetic variant(s) of interest. Along these lines, we characterized the variation of the 5HTTLPR and rs25531 polymorphisms in six samples from North America, Southeast Asia, and Africa (Cameroon) that differ in their racial and ethnic composition. Allele and genotype frequencies were determined for 24,066 participants. Results indicated higher frequencies of the rs25531 G-allele among Black and African populations as compared with White, Hispanic and Asian populations. Further, we observed a greater number of 'extra-long' ('XL') 5HTTLPR alleles than have previously been reported. Extra-long alleles occurred almost entirely among Asian, Black and Non-White Hispanic populations as compared with White and Native American populations where they were completely absent. Lastly, when considered jointly, we observed between sample differences in the genotype frequencies within racial and ethnic populations. Taken together, these data underscore the importance of characterizing the L-G allele to avoid misclassification of participants by genotype and for further studies of the impact XL alleles may have on the transcriptional efficiency of SLC6A4. PMID:25564228

  2. Comparisons of anemia, thrombocytopenia, and neutropenia at initiation of HIV antiretroviral therapy in Africa, Asia, and the Americas

    PubMed Central

    Firnhaber, Cynthia; Smeaton, Laura; Saukila, Nasinuku; Flanigan, Timothy; Gangakhedkar, Raman; Kumwenda, Johnstone; La Rosa, Alberto; Kumarasamy, Nagalingeswaran; De Gruttola, Victor; Hakim, James Gita; Campbell, Thomas B.

    2010-01-01

    Summary Background Hematological abnormalities are common manifestations of advanced HIV-1 infection that could affect the outcomes of highly-active antiretroviral therapy (HAART). Although most HIV-1-infected individuals live in resource-constrained countries, there is little information about the frequency of hematological abnormalities such as anemia, neutropenia, and thrombocytopenia among individuals with advanced HIV-1 disease. Methods This study compared the prevalence of pre-antiretroviral therapy hematological abnormalities among 1571 participants in a randomized trial of antiretroviral efficacy in Africa, Asia, South America, the Caribbean, and the USA. Potential covariates for anemia, neutropenia, and thrombocytopenia were identified in univariate analyses and evaluated in separate multivariable models for each hematological condition. Results The frequencies of neutropenia (absolute neutrophil count ≤ 1.3 × 109/l), anemia (hemoglobin ≤ 10 g/dl), and thrombocytopenia (platelets ≤ 125 × 109/l) at initiation of antiretroviral therapy were 14%, 12%, and 7%, respectively, and varied by country (p < 0.0001 for each). In multivariable models, anemia was associated with gender, platelet count, and country; neutropenia was associated with CD4+ lymphocyte and platelet counts; and thrombocytopenia was associated with country, gender, and chronic hepatitis B infection. Conclusions Differences in the frequency of pretreatment hematological abnormalities could have important implications for the choice of antiretroviral regimen in resource-constrained settings. PMID:20961784

  3. Network analyses of Y-chromosomal types in Europe, northern Africa, and western Asia reveal specific patterns of geographic distribution.

    PubMed

    Malaspina, P; Cruciani, F; Ciminelli, B M; Terrenato, L; Santolamazza, P; Alonso, A; Banyko, J; Brdicka, R; García, O; Gaudiano, C; Guanti, G; Kidd, K K; Lavinha, J; Avila, M; Mandich, P; Moral, P; Qamar, R; Mehdi, S Q; Ragusa, A; Stefanescu, G; Caraghin, M; Tyler-Smith, C; Scozzari, R; Novelletto, A

    1998-09-01

    In a study of 908 males from Europe, northern Africa, and western Asia, the variation of four Y-linked dinucleotide microsatellites was analyzed within three "frames" that are defined by mutations that are nonrecurrent, or nearly so. The rapid generation and extinction of new dinucleotide length variants causes the haplotypes within each lineage to diverge from one another. We constructed networks of "adjacent" haplotypes within each frame, by assuming changes of a single dinucleotide unit. Two small and six large networks were obtained, the latter including 94.9% of the sampled Y chromosomes. We show that the phenetic relationships among haplotypes, represented as a network, result largely from common descent and subsequent molecular radiation. The grouping of haplotypes of the same network thus fits an evolutionarily relevant criterion. Notably, this method allows the total diversity within a sample to be partitioned. Networks can be considered optimal markers for population studies, because reliable frequency estimates can be obtained in small samples. We present synthetic maps describing the incidence of different Y-chromosomal lineages in the extant human populations of the surveyed areas. Dinucleotide diversity also was used to infer time intervals for the coalescence of each network. PMID:9718330

  4. Network analyses of Y-chromosomal types in Europe, northern Africa, and western Asia reveal specific patterns of geographic distribution.

    PubMed Central

    Malaspina, P; Cruciani, F; Ciminelli, B M; Terrenato, L; Santolamazza, P; Alonso, A; Banyko, J; Brdicka, R; García, O; Gaudiano, C; Guanti, G; Kidd, K K; Lavinha, J; Avila, M; Mandich, P; Moral, P; Qamar, R; Mehdi, S Q; Ragusa, A; Stefanescu, G; Caraghin, M; Tyler-Smith, C; Scozzari, R; Novelletto, A

    1998-01-01

    In a study of 908 males from Europe, northern Africa, and western Asia, the variation of four Y-linked dinucleotide microsatellites was analyzed within three "frames" that are defined by mutations that are nonrecurrent, or nearly so. The rapid generation and extinction of new dinucleotide length variants causes the haplotypes within each lineage to diverge from one another. We constructed networks of "adjacent" haplotypes within each frame, by assuming changes of a single dinucleotide unit. Two small and six large networks were obtained, the latter including 94.9% of the sampled Y chromosomes. We show that the phenetic relationships among haplotypes, represented as a network, result largely from common descent and subsequent molecular radiation. The grouping of haplotypes of the same network thus fits an evolutionarily relevant criterion. Notably, this method allows the total diversity within a sample to be partitioned. Networks can be considered optimal markers for population studies, because reliable frequency estimates can be obtained in small samples. We present synthetic maps describing the incidence of different Y-chromosomal lineages in the extant human populations of the surveyed areas. Dinucleotide diversity also was used to infer time intervals for the coalescence of each network. PMID:9718330

  5. Hepatitis B Virus and Hepatitis C Virus Infections in United States-Bound Refugees from Asia and Africa

    PubMed Central

    Mixson-Hayden, Tonya; Lee, Deborah; Ganova-Raeva, Lilia; Drobeniuc, Jan; Stauffer, William M.; Teshale, Eyasu; Kamili, Saleem

    2014-01-01

    The aim of this study was to determine the prevalence of active hepatitis B and C virus infections among refugees from various countries in Africa and Asia. Pre-admission serum samples collected during 2002–2007 from refugees originating from Bhutan (N = 755), Myanmar (N = 1076), Iraq (N = 1137), Laos (N = 593), Thailand (N = 622), and Somalia (N = 707) were tested for hepatitis B virus (HBV) DNA and hepatitis C virus (HCV) RNA. The HBV DNA (genotypes A, B, C, and G) was detected in 12.1% of samples negative for anti-HBs. Highest HBV prevalence was found among Hmong; lowest among Bhutanese. The HCV RNA (genotypes 1a, 1b, 1c, 3b, 6n, and 6m) was detected in 1.3% of the samples. Highest HCV prevalence was found among Hmong from Thailand; lowest among Iraqis. Screening specific refugee groups at high risk for viral hepatitis infections will identify infected individuals who could benefit from referral to care and treatment and prevent further transmissions. PMID:24732462

  6. Hepatitis B virus and hepatitis C virus infections in United States-bound refugees from Asia and Africa.

    PubMed

    Mixson-Hayden, Tonya; Lee, Deborah; Ganova-Raeva, Lilia; Drobeniuc, Jan; Stauffer, William M; Teshale, Eyasu; Kamili, Saleem

    2014-06-01

    The aim of this study was to determine the prevalence of active hepatitis B and C virus infections among refugees from various countries in Africa and Asia. Pre-admission serum samples collected during 2002-2007 from refugees originating from Bhutan (N = 755), Myanmar (N = 1076), Iraq (N = 1137), Laos (N = 593), Thailand (N = 622), and Somalia (N = 707) were tested for hepatitis B virus (HBV) DNA and hepatitis C virus (HCV) RNA. The HBV DNA (genotypes A, B, C, and G) was detected in 12.1% of samples negative for anti-HBs. Highest HBV prevalence was found among Hmong; lowest among Bhutanese. The HCV RNA (genotypes 1a, 1b, 1c, 3b, 6n, and 6m) was detected in 1.3% of the samples. Highest HCV prevalence was found among Hmong from Thailand; lowest among Iraqis. Screening specific refugee groups at high risk for viral hepatitis infections will identify infected individuals who could benefit from referral to care and treatment and prevent further transmissions. PMID:24732462

  7. Correlates of and barriers to the utilization of health services for delivery in South Asia and Sub-Saharan Africa.

    PubMed

    Tey, Nai-Peng; Lai, Siow-li

    2013-01-01

    The high maternal and neonatal mortality rates in South Asia and Sub-Saharan Africa can be attributed to the lack of access and utilization of health services for delivery. Data from the Demographic and Health Surveys conducted in Bangladesh, India, Pakistan, Kenya, Nigeria, and Tanzania show that more than half of the births in these countries were delivered outside a health facility. Institutional delivery was closely associated with educational level, family wealth, place of residence, and women's media exposure status, but it was not influenced by women's work status and their roles in decision-making (with the exception of Nigeria). Controlling for other variables, higher parity and younger women were less likely to use a health facility for delivery. Within each country, the poorer, less educated and rural women had higher unmet need for maternal care services. Service related factors (accessibility in terms of cost and distance) and sociocultural factors (e.g., did not perceive the need for the services and objections from husband and family) also posed as barriers to institutional delivery. The paper concludes with some suggestions to increase institutional delivery. PMID:24288482

  8. Tidal loading along a profile Europe-East Africa-South Asia-Australia and the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Melchior, P.; Moens, M.; Ducarme, B.; van Ruymbeke, M.

    1981-04-01

    Precision measurements of earth tides along a profile stretching from Europe to Polynesia through East Africa, Asia and Australia are used to characterize ocean tides in different basins and thus provide a check on proposed cotidal maps. Ocean tide information was extracted from tidal gravity profiles made with correctly intercalibrated gravimeters at 91 tidal gravity stations by the subtraction of electric earth tide model vectors from the observed tidal vector. Analysis of possible instrumental errors due to calibration, thermal, barometric and power supply interruption effects indicates the data observed at a level of 0.5 microgal cannot be ascribed to computational or instrumental errors. Calculations of the ocean load and attraction signal obtained from the earth tide measurements are observed to be in very good agreement with those obtained from the cotidal maps of Schwiderski (1979, 1980) for satellite altimetry reductions for the diurnal components of the tides, however, less satisfactory agreement is observed in some large areas for the semi-diurnal components. The maps of Hendershott (1973) and Parke (1979) are also found to provide good results in several large areas, but not everywhere. Regions where a more detailed investigation is required are indicated, including Iran-Pakistan, Malaysia, the South China Sea and the South Pacific.

  9. POPULATION FREQUENCIES OF THE TRIALLELIC 5HTTLPR IN SIX ETHNICIALLY DIVERSE SAMPLES FROM NORTH AMERICA, SOUTHEAST ASIA, AND AFRICA

    PubMed Central

    Haberstick, Brett C.; Smolen, Andrew; Williams, Redford B.; Bishop, George D.; Foshee, Vangie A.; Thornberry, Terence P; Conger, Rand; Siegler, Ilene C.; Zhang, Xiaodong; Boardman, Jason D; Frajzyngier, Zygmunt; Stallings, Michael C.; Donnellan, M. Brent; Halpern, Carolyn T.; Harris, Kathleen Mullan

    2015-01-01

    Genetic differences between populations are a potentially an important contributor to health disparities around the globe. As differences in gene frequencies influence study design, it is important to have a thorough understanding of the natural variation of the genetic variant(s) of interest. Along these lines, we characterized the variation of the 5HTTLPR and rs25531 polymorphisms in six samples from North America, Southeast Asia, and Africa (Cameroon) that differ in their racial and ethnic composition. Allele and genotype frequencies were determined for 24,066 participants. Results indicated higher frequencies of the rs25531 G-allele among Black and African populations as compared with White, Hispanic and Asian populations. Further, we observed a greater number of ‘extra-long’ (‘XL’) 5HTTLPR alleles than have previously been reported. Extra-long alleles occurred almost entirely among Asian, Black and Non-White Hispanic populations as compared with White and Native American populations where they were completely absent. Lastly, when considered jointly, we observed between sample differences in the genotype frequencies within racial and ethnic populations. Taken together, these data underscore the importance of characterizing the L-G allele to avoid misclassification of participants by genotype and for further studies of the impact XL alleles may have on the transcriptional efficiency of SLC6A4. PMID:25564228

  10. Vitamin D status in recently arrived immigrants from Africa and Asia: a cross-sectional study from Norway of children, adolescents and adults

    PubMed Central

    Eggemoen, Åse R; Knutsen, Kirsten V; Dalen, Ingvild; Jenum, Anne K

    2013-01-01

    Objectives To estimate the prevalence of vitamin D deficiency (25(OH)D) <50 nmol/L among recently arrived immigrants from Africa and Asia in Oslo, and to explore 25(OH)D levels according to origin, gender and age. Design A cross-sectional study. Setting Primary healthcare unit in Oslo, Norway, offering family immigrants, asylum seekers, United Nations (UN) refugees or individuals granted asylum a free medical examination on arrival. Participants All individuals from African and Asian countries (n=591) referred to the Centre of Migrant Health, Health Agency, Oslo, Norway in 2010, estimated to cover 60% of the targeted population. Results 25(OH)D <50 nmol/L was very prevalent in immigrants from the Middle East (81% (95% CI 75.4% to 86.6%)), South Sahara Africa (73% (CI 67.5% to 78.5%)) and South Asia (75% (CI 64.0% to 86.0%)), in contrast to East Asians (24% (CI 12.6% to 35.4%)), p<0.001 for differences. The prevalence of 25(OH)D<25 nmol/L was lower but followed the same pattern (Middle East: 38% (CI 31.1% to 45.0%), South Sahara Africa: 24% (CI 18.7% to 29.3%) and South Asia: 35% (CI 22.9% to 47.1%), although it was not observed in East Asians (p<0.001 for differences)). The ethnic differences persisted after adjusting for the duration of residence, seasonality and residence status in multiple linear regression analyses. Female adolescents from South Asia, the Middle East and South Sahara Africa had the lowest levels of 25(OH)D. Further, country-specific median levels of 25(OH)D were low (24–38 nmol/L) among groups from Somalia, Eritrea, Afghanistan and Iraq, the countries with the largest number of immigrants in our study. Conclusions The majority of recently settled immigrant groups from the Middle East, South Asia and Africa had 25(OH)D <50 nmol/L, in contrast to East Asians. Female adolescents from these regions had the lowest levels of 25(OH)D. PMID:24157818

  11. Site-specific high-resolution models of the monsoon for Africa and Asia

    NASA Astrophysics Data System (ADS)

    Bryson, R. A.; Bryson, R. U.

    2000-11-01

    Using the macrophysical climate model of Bryson [Bryson, R.A., 1992. A macrophysical model of the Holocene intertropical convergence and jetstream positions and rainfall for the Saharan region. Meteorol. Atmos. Phys., 47, pp. 247-258], it is possible to calculate the monthly latitude of the jetstream and the latitude of the subtropical anticyclones. From these and modern climatic data, it is possible to model the two-century mean latitude of the intertropical convergence (ITC) month by month and estimate the monthly monsoon rainfall using the ITC-Rainfall model of Ilesanmi [Ilesanmi, O.O., 1971. An empirical formulation of an ITD rainfall model for the tropics — a case study of Nigeria. J. Appl. Meteorol., 10, pp. 882-891] and similar relationships. Input to this model is only calculated radiation and atmospheric optical depth estimated from a database of global volcanicity. Recent work has shown that it is possible to extend these estimates to both precipitation and temperature at specific sites, even in mountainous terrain. Testing of the model against archaeological records and climatic proxies is now underway, as well as refining the fundamental model. Preliminary indications are that the timing of fluctuations in the local climate is very well modeled. Especially well matched are the modeled Nile flood based on calculated rainfall on the Blue and White Nile watersheds and the level of Lake Moeris [Hassan, F., 1985. Holocene lakes and prehistoric settlements of the Western Faiyum, Egypt. J. Archaeol. Res., 13, pp. 483-501]. Modeled precipitation histories for specific sites in China, Thailand, the Arabian Peninsula, and North Africa will be presented and contrasted with the simulated rainfall history of Mesopotamia.

  12. Achieving Population-Level Immunity to Rabies in Free-Roaming Dogs in Africa and Asia

    PubMed Central

    Morters, Michelle K.; McKinley, Trevelyan J.; Horton, Daniel L.; Cleaveland, Sarah; Schoeman, Johan P.; Restif, Olivier; Whay, Helen R.; Goddard, Amelia; Fooks, Anthony R.; Damriyasa, I. Made; Wood, James L. N.

    2014-01-01

    Canine rabies can be effectively controlled by vaccination with readily available, high-quality vaccines. These vaccines should provide protection from challenge in healthy dogs, for the claimed period, for duration of immunity, which is often two or three years. It has been suggested that, in free-roaming dog populations where rabies is endemic, vaccine-induced protection may be compromised by immuno-suppression through malnutrition, infection and other stressors. This may reduce the proportion of dogs that seroconvert to the vaccine during vaccination campaigns and the duration of immunity of those dogs that seroconvert. Vaccination coverage may also be limited through insufficient vaccine delivery during vaccination campaigns and the loss of vaccinated individuals from populations through demographic processes. This is the first longitudinal study to evaluate temporal variations in rabies vaccine-induced serological responses, and factors associated with these variations, at the individual level in previously unvaccinated free-roaming dog populations. Individual-level serological and health-based data were collected from three cohorts of dogs in regions where rabies is endemic, one in South Africa and two in Indonesia. We found that the vast majority of dogs seroconverted to the vaccine; however, there was considerable variation in titres, partly attributable to illness and lactation at the time of vaccination. Furthermore, >70% of the dogs were vaccinated through community engagement and door-to-door vaccine delivery, even in Indonesia where the majority of the dogs needed to be caught by net on successive occasions for repeat blood sampling and vaccination. This demonstrates the feasibility of achieving population-level immunity in free-roaming dog populations in rabies-endemic regions. However, attrition of immune individuals through demographic processes and waning immunity necessitates repeat vaccination of populations within at least two years to ensure

  13. Europa Tide Movie

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for Europa Tide Movie

    In this movie Europa is seen in a cutaway view through two cycles of its 3.5 day orbit about the giant planet Jupiter. Like Earth, Europa is thought to have an iron core, a rocky mantle and a surface ocean of salty water. Unlike on Earth, however, this ocean is deep enough to cover the whole moon, and being far from the sun, the ocean surface is globally frozen over. Europa's orbit is eccentric, which means as it travels around Jupiter, large tides, raised by Jupiter, rise and fall. Jupiter's position relative to Europa is also seen to librate, or wobble, with the same period. This tidal kneading causes frictional heating within Europa, much in the same way a paper clip bent back and forth can get hot to the touch, as illustrated by the red glow in the interior of Europa's rocky mantle and in the lower, warmer part of its ice shell. This tidal heating is what keeps Europa's ocean liquid and could prove critical to the survival of simple organisms within the ocean, if they exist.

  14. Geology of Europa

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Chyba, C.; Head, J. W.; McCord, T.; McKinnon, W. B.; Pappalardo, R. T.

    2004-01-01

    Europa is a rocky object of radius 1565 km (slightly smaller than Earth s moon) and has an outer shell of water composition estimated to be of order 100 km thick, the surface of which is frozen. The total volume of water is about 3 x 10(exp 9) cubic kilometers, or twice the amount of water on Earth. Moreover, like its neighbor Io, Europa experiences internal heating generated from tidal flexing during its eccentric orbit around Jupiter. This raises the possibility that some of the water beneath the icy crust is liquid. The proportion of rock to ice, the generation of internal heat, and the possibility of liquid water make Europa unique in the Solar System. In this chapter, we outline the sources of data available for Europa (with a focus on the Galileo mission), review previous and on-going research on its surface geology, discuss the astrobiological potential of Europa, and consider plans for future exploration.

  15. REASON for Europa

    NASA Astrophysics Data System (ADS)

    Moussessian, A.; Blankenship, D. D.; Plaut, J. J.; Patterson, G. W.; Gim, Y.; Schroeder, D. M.; Soderlund, K. M.; Grima, C.; Young, D. A.; Chapin, E.

    2015-12-01

    The science goal of the Europa multiple flyby mission is to "explore Europa to investigate its habitability". One of the primary instruments selected for the scientific payload is a multi-frequency, multi-channel ice penetrating radar system. This "Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON)" would revolutionize our understanding of Europa's ice shell by providing the first direct measurements of its surface character and subsurface structure. REASON addresses key questions regarding Europa's habitability, including the existence of any liquid water, through the innovative use of radar sounding, altimetry, reflectometry, and plasma/particles analyses. These investigations require a dual-frequency radar (HF and VHF frequencies) instrument with concurrent shallow and deep sounding that is designed for performance robustness in the challenging environment of Europa. The flyby-centric mission configuration is an opportunity to collect and transmit minimally processed data back to Earth and exploit advanced processing approaches developed for terrestrial airborne data sets. The observation and characterization of subsurface features beneath Europa's chaotic surface require discriminating abundant surface clutter from a relatively weak subsurface signal. Finally, the mission plan also includes using REASON as a nadir altimeter capable of measuring tides to test ice shell and ocean hypotheses as well as characterizing roughness across the surface statistically to identify potential follow-on landing sites. We will present a variety of measurement concepts for addressing these challenges.

  16. Interior of Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Cutaway view of the possible internal structure of Europa The surface of the satellite is a mosaic of images obtained in 1979 by NASA's Voyager spacecraft. The interior characteristics are inferred from gravity field and magnetic field measurements by NASA's Galileo spacecraft. Europa's radius is 1565 km, not too much smaller than our Moon's radius. Europa has a metallic (iron, nickel) core (shown in gray) drawn to the correct relative size. The core is surrounded by a rock shell (shown in brown). The rock layer of Europa (drawn to correct relative scale) is in turn surrounded by a shell of water in ice or liquid form (shown in blue and white and drawn to the correct relative scale). The surface layer of Europa is shown as white to indicate that it may differ from the underlying layers. Galileo images of Europa suggest that a liquid water ocean might now underlie a surface ice layer several to ten kilometers thick. However, this evidence is also consistent with the existence of a liquid water ocean in the past. It is not certain if there is a liquid water ocean on Europa at present.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  17. Modeling Europa's Dust Plumes

    NASA Astrophysics Data System (ADS)

    Southworth, B.; Kempf, S.; Schmidt, J.

    2015-12-01

    The discovery of Europa maintaining a probably sporadic water vapor plume constitutes a huge scientific opportunity for NASA's upcoming mission to this Galilean moon. Measuring the properties of material emerging from interior sources offers a unique chance to understand conditions at Europa's subsurface ocean. Exploiting results obtained for the Enceladus plume, we adjust the ejection model by Schmidt et al. [2008] to the conditions at Europa. In this way, we estimate properties of a possible, yet unobserved dust component of the Europa plume. For a size-dependent speed distribution of emerging ice particles we use the model from Kempf et al. [2010] for grain dynamics, modified to run simulations of plumes on Europa. Specifically, we model emission from the two plume locations determined from observations by Roth et al. [2014] and also from other locations chosen at the closest approach of low-altitude flybys investigated in the Europa Clipper study. This allows us to estimate expected fluxes of ice grains on the spacecraft. We then explore the parameter space of Europa dust plumes with regard to particle speed distribution parameters, plume location, and spacecraft flyby elevation. Each parameter set results in a 3-dimensional particle density structure through which we simulate flybys, and a map of particle fallback ('snowfall') on the surface of Europa. Due to the moon's high escape speed, a Europa plume will eject few to no particles that can escape its gravity, which has several further consequences: (i) For given ejection velocity a Europa plume will have a smaller scale height, with a higher particle number densities than the plume on Enceladus, (ii) plume particles will not feed the diffuse Galilean dust ring, (iii) the snowfall pattern on the surface will be more localized about the plume location, and will not induce a global m = 2 pattern as seen on Enceladus, and (iv) safely observing an active plume will require low altitude flybys, preferably at 50

  18. Use of anchoring vignettes to evaluate health reporting behavior amongst adults aged 50 years and above in Africa and Asia – testing assumptions

    PubMed Central

    Hirve, Siddhivinayak; Gómez-Olivé, Xavier; Oti, Samuel; Debpuur, Cornelius; Juvekar, Sanjay; Tollman, Stephen; Blomstedt, Yulia; Wall, Stig; Ng, Nawi

    2013-01-01

    Background Comparing self-rating health responses across individuals and cultures is misleading due to different reporting behaviors. Anchoring vignettes is a technique that allows identifying and adjusting self-rating responses for reporting heterogeneity (RH). Objective This article aims to test two crucial assumptions of vignette equivalence (VE) and response consistency (RC) that are required to be met before vignettes can be used to adjust self-rating responses for RH. Design We used self-ratings, vignettes, and objective measures covering domains of mobility and cognition from the WHO study on global AGEing and adult health, administered to older adults aged 50 years and above from eight low- and middle-income countries in Africa and Asia. For VE, we specified a hierarchical ordered probit (HOPIT) model to test for equality of perceived vignette locations. For RC, we tested for equality of thresholds that are used to rate vignettes with thresholds derived from objective measures and used to rate their own health function. Results There was evidence of RH in self-rating responses for difficulty in mobility and cognition. Assumptions of VE and RC between countries were violated driven by age, sex, and education. However, within a country context, assumption of VE was met in some countries (mainly in Africa, except Tanzania) and violated in others (mainly in Asia, except India). Conclusion We conclude that violation of assumptions of RC and VE precluded the use of anchoring vignettes to adjust self-rated responses for RH across countries in Asia and Africa. PMID:24011254

  19. Europa's petrological thermal history

    NASA Technical Reports Server (NTRS)

    Ransford, G. A.; Finnerty, A. A.; Collerson, K. D.

    1981-01-01

    A path of geophysical development which takes into account the petrological sequence is presented to describe the thermal evolution of Europa. On the basis of considerations of the likely temperature-pressure conditions in the Europa zone of the circumjovian nebula during the condensation of the satellite on the one hand and of the early thermal evolution on the other, it is argued that most of the water of Europa can be in the form of hydrated silicates in a thick convective boundary layer or throughout the body of the satellite. Such silicates would include the minerals chlorite and/or serpentine, and brucite, and could be maintained in hydrated states by solid state convection within the body. The model predicts that the ice layer on the surface of Europa is considerably thinner than the 150 km that had been estimated before the Voyager mission.

  20. Adult non-communicable disease mortality in Africa and Asia: evidence from INDEPTH Health and Demographic Surveillance System sites

    PubMed Central

    Streatfield, P. Kim; Khan, Wasif A.; Bhuiya, Abbas; Hanifi, Syed M.A.; Alam, Nurul; Bagagnan, Cheik H.; Sié, Ali; Zabré, Pascal; Lankoandé, Bruno; Rossier, Clementine; Soura, Abdramane B.; Bonfoh, Bassirou; Kone, Siaka; Ngoran, Eliezer K.; Utzinger, Juerg; Haile, Fisaha; Melaku, Yohannes A.; Weldearegawi, Berhe; Gomez, Pierre; Jasseh, Momodou; Ansah, Patrick; Debpuur, Cornelius; Oduro, Abraham; Wak, George; Adjei, Alexander; Gyapong, Margaret; Sarpong, Doris; Kant, Shashi; Misra, Puneet; Rai, Sanjay K.; Juvekar, Sanjay; Lele, Pallavi; Bauni, Evasius; Mochamah, George; Ndila, Carolyne; Williams, Thomas N.; Laserson, Kayla F.; Nyaguara, Amek; Odhiambo, Frank O.; Phillips-Howard, Penelope; Ezeh, Alex; Kyobutungi, Catherine; Oti, Samuel; Crampin, Amelia; Nyirenda, Moffat; Price, Alison; Delaunay, Valérie; Diallo, Aldiouma; Douillot, Laetitia; Sokhna, Cheikh; Gómez-Olivé, F. Xavier; Kahn, Kathleen; Tollman, Stephen M.; Herbst, Kobus; Mossong, Joël; Chuc, Nguyen T.K.; Bangha, Martin; Sankoh, Osman A.; Byass, Peter

    2014-01-01

    Background Mortality from non-communicable diseases (NCDs) is a major global issue, as other categories of mortality have diminished and life expectancy has increased. The World Health Organization's Member States have called for a 25% reduction in premature NCD mortality by 2025, which can only be achieved by substantial reductions in risk factors and improvements in the management of chronic conditions. A high burden of NCD mortality among much older people, who have survived other hazards, is inevitable. The INDEPTH Network collects detailed individual data within defined Health and Demographic Surveillance sites. By registering deaths and carrying out verbal autopsies to determine cause of death across many such sites, using standardised methods, the Network seeks to generate population-based mortality statistics that are not otherwise available. Objective To describe patterns of adult NCD mortality from INDEPTH Network sites across Africa and Asia, according to the WHO 2012 verbal autopsy (VA) cause categories, with separate consideration of premature (15–64 years) and older (65+ years) NCD mortality. Design All adult deaths at INDEPTH sites are routinely registered and followed up with VA interviews. For this study, VA archives were transformed into the WHO 2012 VA standard format and processed using the InterVA-4 model to assign cause of death. Routine surveillance data also provide person-time denominators for mortality rates. Results A total of 80,726 adult (over 15 years) deaths were documented over 7,423,497 person-years of observation. NCDs were attributed as the cause for 35.6% of these deaths. Slightly less than half of adult NCD deaths occurred in the 15–64 age group. Detailed results are presented by age and sex for leading causes of NCD mortality. Per-site rates of NCD mortality were significantly correlated with rates of HIV/AIDS-related mortality. Conclusions These findings present important evidence on the distribution of NCD mortality

  1. Neonatal severe bacterial infection impairment estimates in South Asia, sub-Saharan Africa, and Latin America for 2010

    PubMed Central

    Seale, Anna C.; Blencowe, Hannah; Zaidi, Anita; Ganatra, Hammad; Syed, Sana; Engmann, Cyril; Newton, Charles R.; Vergnano, Stefania; Stoll, Barbara J.; Cousens, Simon N.; Lawn, Joy E.

    2013-01-01

    Background: Survivors of neonatal infections are at risk of neurodevelopmental impairment (NDI), a burden not previously systematically quantified and yet important for program priority setting. Systematic reviews and meta-analyses were undertaken and applied in a three-step compartmental model to estimate NDI cases after severe neonatal bacterial infection in South Asia, sub-Saharan Africa, and Latin America in neonates of >32 wk gestation (or >1,500 g). Methods: We estimated cases of sepsis, meningitis, pneumonia, or no severe bacterial infection from among estimated cases of possible severe bacterial infection ((pSBI) step 1). We applied respective case fatality risks ((CFRs) step 2) and the NDI risk among survivors (step 3). For neonatal tetanus, incidence estimates were based on the estimated deaths, CFRs, and risk of subsequent NDI. Results: For 2010, we estimated 1.7 million (uncertainty range: 1.1–2.4 million) cases of neonatal sepsis, 200,000 (21,000–350,000) cases of meningitis, 510,000 cases (150,000–930,000) of pneumonia, and 79,000 cases (70,000–930,000) of tetanus in neonates >32 wk gestation (or >1,500 g). Among the survivors, we estimated moderate to severe NDI after neonatal meningitis in 23% (95% confidence interval: 19–26%) of survivors, 18,000 (2,700–35,000) cases, and after neonatal tetanus in 16% (6–27%), 4,700 cases (1,700–8,900). Conclusion: Data are lacking for impairment after neonatal sepsis and pneumonia, especially among those of >32 wk gestation. Improved recognition and treatment of pSBI will reduce neonatal mortality. Lack of follow-up data for survivors of severe bacterial infections, particularly sepsis, was striking. Given the high incidence of sepsis, even minor NDI would be of major public health importance. Prevention of neonatal infection, improved case management, and support for children with NDI are all important strategies, currently receiving limited policy attention. PMID:24366464

  2. Seeking Europa's Ocean

    NASA Astrophysics Data System (ADS)

    Pappalardo, Robert T.

    2010-01-01

    Galileo spacecraft data suggest that a global ocean exists beneath the frozen ice surface Jupiter's moon Europa. Since the early 1970s, planetary scientists have used theoretical and observational arguments to deliberate the existence of an ocean within Europa and other large icy satellites. Galileo magnetometry data indicates an induced magnetic field at Europa, implying a salt water ocean. A paucity of large craters argues for a surface on average only ~40-90 Myr old. Two multi-ring structures suggest that impacts punched through an ice shell ~20 km thick. Europa's ocean and surface are inherently linked through tidal deformation of the floating ice shell, and tidal flexing and nonsynchronous rotation generate stresses that fracture and deform the surface to create ridges and bands. Dark spots, domes, and chaos terrain are probably related to tidally driven ice convection along with partial melting within the ice shell. Europa's geological activity and probable mantle contact permit the chemical ingredients necessary for life to be present within the satellite's ocean. Astonishing geology and high astrobiological potential make Europa a top priority for future spacecraft exploration, with a primary goal of assessing its habitability.

  3. Africa.

    ERIC Educational Resources Information Center

    Happel, Sue; Loeb, Joyce

    Although the activities in this unit are designed primarily for students in the intermediate grades, the document's text, illustrations, and bibliographic references are suitable for anyone interested in learning about Africa. Following a brief introduction and map work, the document is arranged into six sections. Section 1 traces Africa's history…

  4. Africa.

    ERIC Educational Resources Information Center

    Martz, Carlton

    2001-01-01

    This publication explores issues related to Africa. It examines the U.S. response to the Barbary pirate states (Morocco, Algiers, Tunis, Tripoli) in the early 19th century; the current AIDS crisis in Africa; and 14th century Mali and other Islamic lands through the eyes of Ibn Battuta, who traveled throughout the Muslim world. Each article…

  5. Sulfuric Acid on Europa

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain.

    This image is based on data gathered by Galileo's near infrared mapping spectrometer.

    Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks.

    Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  6. Ruddy 'Freckles' on Europa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Reddish spots and shallow pits pepper the enigmatic ridged surface of Europa in this view combining information from images taken by NASA's Galileo spacecraft during two different orbits around Jupiter.

    The spots and pits visible in this region of Europa's northern hemisphere are each about 10 kilometers (6 miles) across. The dark spots are called 'lenticulae,' the Latin term for freckles. Their similar sizes and spacing suggest that Europa's icy shell may be churning away like a lava lamp, with warmer ice moving upward from the bottom of the ice shell while colder ice near the surface sinks downward. Other evidence has shown that Europa likely has a deep melted ocean under its icy shell. Ruddy ice erupting onto the surface to form the lenticulae may hold clues to the composition of the ocean and to whether it could support life.

    The image combines higher-resolution information obtained when Galileo flew near Europa on May 31, 1998, during the spacecraft's 15th orbit of Jupiter, with lower-resolution color information obtained on June 28, 1996, during Galileo's first orbit.

    The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. Additional information about Galileo and its discoveries is available on the Galileo mission home page at http://galileo.jpl.nasa.gov .

  7. Macula on Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image of Europa, an icy satellite of Jupiter about the size of the Earth's Moon, was obtained from a range of 7415 miles (11933 kilometers) by the Galileo spacecraft during its fourth orbit around Jupiter and its first close pass of Europa. The image spans 30 miles by 57 miles (48 km by 91 km) and shows features as small as 800 feet (240 meters) across. The large circular feature centered in the upper middle of the image is called a macula, and could be the scar of a large meteorite impact. The surface of Europa is composed mostly of water ice, so large impact craters on Europa could look different from large bowl-shaped depressions formed by impact into rock, such as on the Moon. On Europa's icy surface, the original impact crater has been modified into a central zone of rugged topography surrounded by circular fractures which reflect adjustments to stress in the surrounding icy crust.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  8. Daytime Temperatures on Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This infrared image of Europa, showing heat radiation from its surface at a wavelength of 27 microns (millionths of a meter), provides the best view yet of Europa's daytime temperatures. Temperatures, derived from the brightness of the infrared radiation, can be determined from the colors by reference to the scale at the bottom of the image.

    The image, taken by NASA's Galileo spacecraft, shows the full disk of Europa, highly distorted by the relative motion of Europa and the spacecraft, centered on longitude 190 degrees, with north at the top. The data show that midday temperatures at Europa's equator reach about 130 degrees Kelvin (-225 F). The surface is even colder toward the poles and before or after midday. Small patches of different colors on Europa's disk show regions that are warmer or cooler than their immediate surroundings: the warm patches are generally relatively dark, and thus absorb more sunlight, than neighboring regions, while the cool patches are relatively bright. In the lower left corner, heat radiation from Jupiter itself, appearing orange-red in this representation, can be seen peeking out from behind Europa's disk.

    The image was taken with Galileo's PPR (Photopolarimeter-Radiometer) instrument on the spacecraft's seventh orbit around Jupiter, from a range of about 65,000 kilometers (40,389 miles). Surface temperatures derived from the strength of infrared radiation, as was done here, are called 'brightness temperatures', and may be slightly in error.

    The PPR instrument builds up an image by slowly scanning across the target over a period of up to one hour. The motion of Galileo relative to Europa during this time causes distortions in the satellite shape on the image, which therefore does not appear circular. The small overlapping circles that make up the image show the size of the area, about 160 kilometers (99 miles) across, covered by each individual PPR measurement. Blue spots in the dark sky in the right-hand portion of the

  9. Estimates of possible severe bacterial infection in neonates in sub-Saharan Africa, south Asia, and Latin America for 2012: a systematic review and meta-analysis

    PubMed Central

    Seale, Anna C; Blencowe, Hannah; Manu, Alexander A; Nair, Harish; Bahl, Rajiv; Qazi, Shamim A; Zaidi, Anita K; Berkley, James A; Cousens, Simon N; Lawn, Joy E

    2014-01-01

    Summary Background Bacterial infections are a leading cause of the 2·9 million annual neonatal deaths. Treatment is usually based on clinical diagnosis of possible severe bacterial infection (pSBI). To guide programme planning, we have undertaken the first estimates of neonatal pSBI, by sex and by region, for sub-Saharan Africa, south Asia, and Latin America. Methods We included data for pSBI incidence in neonates of 32 weeks' gestation or more (or birthweight ≥1500 g) with livebirth denominator data, undertaking a systematic review and forming an investigator group to obtain unpublished data. We calculated pooled risk estimates for neonatal pSBI and case fatality risk, by sex and by region. We then applied these risk estimates to estimates of livebirths in sub-Saharan Africa, south Asia, and Latin America to estimate cases and associated deaths in 2012. Findings We included data from 22 studies, for 259 944 neonates and 20 196 pSBI cases, with most of the data (18 of the 22 studies) coming from the investigator group. The pooled estimate of pSBI incidence risk was 7·6% (95% CI 6·1–9·2%) and the case-fatality risk associated with pSBI was 9·8% (7·4–12·2). We estimated that in 2012 there were 6·9 million cases (uncertainty range 5·5 million–8·3 million) of pSBI in neonates needing treatment: 3·5 million (2·8 million–4·2 million) in south Asia, 2·6 million (2·1 million–3·1 million) in sub-Saharan Africa, and 0·8 million (0·7 million–1·0 million) in Latin America. The risk of pSBI was greater in boys (risk ratio 1·12, 95% CI 1·06–1·18) than girls. We estimated that there were 0·68 million (0·46 million–0·92 million) neonatal deaths associated with pSBI in 2012. Interpretation The need-to-treat population for pSBI in these three regions is high, with ten cases of pSBI diagnosed for each associated neonatal death. Deaths and disability can be reduced through improved prevention, detection, and case management. Funding The

  10. REASON for Europa

    NASA Astrophysics Data System (ADS)

    Patterson, Gerald Wesley; Blankenship, Don; Moussessian, Alina; Plaut, Jeffrey; Gim, Yonggyu; Schroeder, Dustin; Soderlund, Krista; Grima, Cyril; Chapin, Elaine

    2015-11-01

    The science goal of the Europa multiple flyby mission is to “explore Europa to investigate its habitability”. One of the primary instruments selected for the scientific payload is a multi-frequency, multi-channel ice penetrating radar system. This “Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON)” would revolutionize our understanding of Europa’s ice shell by providing the first direct measurements of its surface character and subsurface structure. REASON will address key questions regarding Europa’s habitability, including the existence of any liquid water, through the innovative use of radar sounding, altimetry, reflectometry, and plasma/particles analyses. These investigations require a dual-frequency radar (HF and VHF frequencies) instrument with simultaneous shallow and deep sounding that is designed for performance robustness in the challenging environment of Europa. The flyby-centric mission configuration is an opportunity to collect and transmit minimally processed data back to Earth and exploit advanced processing approaches developed for terrestrial airborne data sets. The observation and characterization of subsurface features beneath Europa’s chaotic surface requires discriminating abundant surface clutter from a relatively weak subsurface signal. Finally, the mission plan also includes using REASON as a nadir altimeter capable of measuring tides to test ice shell and ocean hypotheses as well as characterizing roughness across the surface statistically to identify potential follow-on landing sites. We will present a variety of measurement concepts for addressing these challenges.

  11. [The characteristics of the macro- and trace element composition of the hair in the peoples of Asia, Africa and Latin America].

    PubMed

    Pavlov, Iu V; Alisievich, V I

    1999-01-01

    Macro- and trace element composition of hairs on the head, chest, in the armpits, and on the pubis in the population of Asia, Africa, and Latin America adapted and not to the climate, geographic and ecological conditions of the Russian Federation (Moscow) is studied by spectrography (DPS-13 spectrograph). Element composition of residents of 16 countries is analyzed by variation statistics methods using PC: Lebanon, Syria, Yemen, Bahrain, India, Sierra Leone, Côte d'Ivoire, Rwanda, Kenya, Sudan, Mexico, Ecuador, Bolivia, Brasilia, Columbia, and Chile. Hairs from residents of East Europe (Russians, Byelorussians, Ukrainians) living in Moscow for 6-8 years (adapted) were the reference for comparison. A total of 371 specimens of hairs were examined. Hairs from adapted and not adapted residents of the above-listed countries and continents differ significantly from each other and from the hairs of Russians, Byelorussians, and Ukrainians living in Moscow. PMID:10224921

  12. Europa's Great Lakes

    NASA Astrophysics Data System (ADS)

    Schmidt, B. E.; Blankenship, D. D.; Patterson, G. W.; Schenk, P. M.

    2012-04-01

    Unique to the surface of Europa, chaos terrain is diagnostic of the properties and dynamics of its icy shell. While models have suggested that partial melt within a thick shell or melt-through of a thin shell may form chaos, neither model has been able to definitively explain all observations of chaos terrain. However, we present a new model that suggests large melt lenses form within the shell and that water-ice interactions above and within these lenses drive the production of chaos. Our analysis of the geomorphology of Conamara Chaos and Thera Macula, was used to infer and test a four-stage lens-collapse chaos formation model: 1) Thermal plumes of warm, pure ice ascend through the shell melting the impure brittle ice above, producing a lake of briny water and surface down draw due to volume reduction. 2) Surface deflection and driving force from the plume below hydraulically seals the water in place. 3) Extension of the brittle ice lid generates fractures from below, allowing brines to enter and fluidize the ice matrix. 4) As the lens and now brash matrix refreeze, thermal expansion creates domes and raises the chaos feature above the background terrain. This new "lense-collapse" model indicates that chaos features form in the presence of a great deal of liquid water, and that large liquid water bodies exist within 3km of Europa's surface comparable in volume to the North American Great Lakes. The detection of shallow subsurface "lakes" implies that the ice shell is recycling rapidly and that Europa may be currently active. In this presentation, we will explore environments on Europa and their analogs on Earth, from collapsing Antarctic ice shelves to to subglacial volcanos in Iceland. I will present these new analyses, and describe how this new perspective informs the debate about Europa's habitability and future exploration.

  13. Investigation of Europa's Exosphere

    NASA Astrophysics Data System (ADS)

    Wurz, Peter; Vorburger, Audrey; Galli, André; Mousis, Olivier; Lammer, Helmut; Barabash, Stas

    2014-05-01

    The European Space Agency has selected the Jupiter Icy Moons Explorer (JUICE) mission to fly to the Jupiter system and visit the moons Europa, Ganymede, and Callisto. One of the selected scientific instruments is the Particle Environment Package (PEP) that includes a Neutral gas and Ion mass spectrometer (NIM). NIM will measure the composition of the exospheres of these three moons during flybys and in orbit of Ganymede. Since all these exospheres are in direct contact with the surface of the respective moon, the chemical composition of the surface can be inferred from of the exospheric measurements. Knowing the chemical composition of the surface, and accounting for radiation induced chemistry at and near the surface, one can compare with models of the formation of these icy satellites from the proto-planetary disk from which Jupiter and the icy moons formed. In addition, if the JUICE flyby trajectory allows sampling the recently discovered plume on Europa with NIM we can measure the composition of Europa's ocean, which again can be compared to formation models, which would provide strong constraints on its formation conditions. We will present Monte Carlo calculations of Europa's exosphere including all relevant processes to release particles into the exosphere, which are sublimation, sputtering, and the plume release. For the surface composition we compiled composition data from existing spectroscopic observations and from formation models. We derive density profiles for different scenarios (e.g. day / night, in co-rotation flow, ...), and make predictions on the expected NIM measurements for the planned Europa flyby trajectories of JUICE

  14. Strategies to improve follow-up of children after surgery for cataract: findings from Child Eye Health Tertiary Facilities in sub-Saharan Africa and South Asia.

    PubMed

    Kishiki, E; van Dijk, K; Courtright, P

    2016-09-01

    PurposeWe sought to conduct a systematic literature review on follow-up of children with ocular surgical management (primarily childhood cataract) in developing countries. Second, we sought to determine the current practices regarding follow-up for clinical, optical, low vision, rehabilitation, and educational placement among children receiving surgical services at Child Eye Health Tertiary Facilities (CEHTF) in sub-Saharan Africa (SSA) and South Asia.MethodsA systematic literature review was conducted. Separately, we conducted a cross-sectional study among CEHTF in SSA and South Asia (India, Nepal, and Bangladesh) to assess current capacities and practices related to follow-up and educational placement.ResultsThe articles that met the systematic review eligibility criteria could be grouped into two areas: factors and strategies to improve post-operative follow-up and educational placement of children after surgery. Among the 106 CEHTF in SSA and South Asia, responses were provided by 75 CEHTF. Only 59% of CEHTF reported having a Childhood Blindness and Low Vision Coordinator; having a coordinator was associated with having appropriate follow-up mechanisms in place. Educational referral practices were associated with having a low-vision technician, having low-vision devices, and having donor support for these services.ConclusionsThe systematic literature review revealed evidence of poor follow-up after surgical interventions for cataract and other conditions, but also showed that follow-up could be improved significantly if specific strategies were adopted. Approaches to follow-up are generally inadequate at most facilities and there is little external support for follow-up. Findings suggest that funding and supporting a coordinator would assist in ensuring that good practices for follow-up (cell phone reminders, patient tracking, and reimbursement of transport) were followed. PMID:27472213

  15. Return to Europa: Overview of the Jupiter Europa Orbiter Mission

    NASA Technical Reports Server (NTRS)

    Clark, K.; Tan-Wang, G.; Boldt, J.; Greeley, R.; Jun, I.; Lock, R.; Ludwinski, J.; Pappalardo, R.; Van Houten, T.; Yan, T.

    2009-01-01

    Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, Galileo supplied fascinating new insights into that satellite's secrets. The Jupiter Europa Orbiter (JEO) would be the NASA-led portion of the Europa Jupiter System Mission (EJSM), an international mission with orbiters developed by NASA, ESA and possibly JAXA. JEO would address a very important subset of the complete EJSM science objectives and is designed to function alone or in conjunction with ESA's Jupiter Ganymede Orbiter (JGO).

  16. Voyager photometry of Europa

    NASA Technical Reports Server (NTRS)

    Buratti, B.; Veverka, J.

    1983-01-01

    The photometric properties of Europa are derived through an analysis of 90 Voyager images with 3-143 deg phase angles in the spectral range from 0.34 to 0.58 microns. It is noted that, at small phase angles, the disk-integrated phase curve shows almost no evidence of an opposition effect. The scattering properties of Europa in general, and of the bright plain and dark mottled terrain types, cannot be represented by a lunar-like photometric law, although an equation which is a linear superposition of a lunar-like scattering law and a Lambert component provides an adequate and simple representation of scattering properties. The plains are photometrically more homogeneous than the mottled terrain, and these two terrain types exhibit an average normal reflectance of 0.71 on both leading and trailing hemispheres and of 0.60 on leading and 0.48 on trailing hemispheres, respectively.

  17. Europa Triple Band

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This picture of Europa, a moon of Jupiter, was obtained on February 20, 1997, by the Solid State Imaging system onboard the Galileo spacecraft during its sixth orbit around Jupiter. The area is centered at 9.3 degrees north latitude, 275.7 degrees west longitude, on the trailing hemisphere of Europa. As Europa moves in its orbit around Jupiter, the trailing hemisphere is the portion which is always on the moon's backside opposite to its direction of motion. The area depicted is about 32 kilometers by 40 kilometers (20 miles by 25 miles). Resolution is 54 meters (59 yards). The Sun illuminates the scene from the right (east).

    A section of a triple band crosses the upper left of the picture and extends for hundreds of miles across the surface. Triple bands derive their name from their appearance at lower resolution as a narrow bright band flanked by a pair of darker bands. At the high resolution of this picture, however, the triple band is much more complex and is composed of a system of ridges 6 kilometers (4 miles) across. Some ridges reach heights of about 180 meters (200 yards). Other features include a hill in the center of the picture about 480 meters (500 yards) high. Two mounds about 6 kilometers across (4 miles) are seen in the bottom of the picture. The ridges, hills and mounds probably all represent uplifts of the icy crust of Europa by processes originating from the interior.

    The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington D.C. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at: http://galileo.jpl.nasa.gov.

  18. Europa Ice Floes

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Jupiter's moon Europa, as seen in this image taken June 27, 1996 by NASA's Galileo spacecraft, displays features in some areas resembling ice floes seen in Earth's polar seas. Europa, about the size of Earth's moon, has an icy crust that has been severely fractured, as indicated by the dark linear, curved, and wedged-shaped bands seen here. These fractures have broken the crust into plates as large as 30 kilometers (18.5 miles) across. Areas between the plates are filled with material that was probably icy slush contaminated with rocky debris. Some individual plates were separated and rotated into new positions. Europa's density indicates that it has a shell of water ice thicker than 100 kilometers (about 60 miles), parts of which could be liquid. Currently, water ice could extend from the surface down to the rocky interior, but the features seen in this image suggest that motion of the disrupted icy plates was lubricated by soft ice or liquid water below the surface at the time of disruption. This image covers part of the equatorial zone of Europa and was taken from a distance of 156,000 kilometers (about 96,300 miles) by the Solid-state Imaging Subsystem on the Galileo spacecraft. North is to the right and the sun is nearly directly overhead. The area shown is about 510 by 989 kilometers (310-by-600 miles), and the smallest visible feature is about 1.6 kilometers (1 mile) across.

    The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http:// www.jpl.nasa.gov/galileo/sepo.

  19. Europa's Broken Ice

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Jupiter's moon Europa, as seen in this image taken June 27, 1996 by NASA's Galileo spacecraft, displays features in some areas resembling ice floes seen in Earth's polar seas. Europa, about the size of Earth's moon, has an icy crust that has been severely fractured, as indicated by the dark linear, curved, and wedged-shaped bands seen here. These fractures have broken the crust into plates as large as 30 kilometers (18.5 miles) across. Areas between the plates are filled with material that was probably icy slush contaminated with rocky debris. Some individual plates were separated and rotated into new positions. Europa's density indicates that it has a shell of water ice as thick as 100 kilometers (about 60 miles), parts of which could be liquid. Currently, water ice could extend from the surface down to the rocky interior, but the features seen in this image suggest that motion of the disrupted icy plates was lubricated by soft ice or liquid water below the surface at the time of disruption. This image covers part of the equatorial zone of Europa and was taken from a distance of 156,000 kilometers (about 96,300 miles) by the solid-state imager camera on the Galileo spacecraft. North is to the right and the sun is nearly directly overhead. The area shown is about 360 by 770 kilometers (220-by-475 miles or about the size of Nebraska), and the smallest visible feature is about 1.6 kilometers (1 mile) across. The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science.

  20. Pwyll Crater on Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This enhanced color image of the region surrounding the young impact crater Pwyll on Jupiter's moon Europa was produced by combining low resolution color data with a higher resolution mosaic of images obtained on December 19, 1996 by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft. This region is on the trailing hemisphere of the satellite, centered at 11 degrees South and 276 degrees West, and is about 1240 kilometers across. North is toward the top of the image, and the sun illuminates the surface from the east.

    The 26 kilometer diameter impact crater Pwyll, just below the center of the image, is thought to be one of the youngest features on the surface of Europa. The diameter of the central dark spot, ejecta blasted from beneath Europa's surface, is approximately 40 kilometers, and bright white rays extend for over a thousand kilometers in all directions from the impact site. These rays cross over many different terrain types, indicating that they are younger than anything they cross. Their bright white color may indicate that they are composed of fresh, fine water ice particles, as opposed to the blue and brown tints of older materials elsewhere in the image.

    Also visible in this image are a number of the dark lineaments which are called 'triple bands' because they have a bright central stripe surrounded by darker material. Scientists can use the order in which these bands cross each other to determine their relative ages, as they attempt to reconstruct the geologic history of Europa.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  1. Europa's Active Surface

    NASA Technical Reports Server (NTRS)

    1996-01-01

    A newly discovered impact crater can be seen just right of the center of this image of Jupiter's moon Europa returned by NASA's Galileo spacecraft camera. The crater is about 30 kilometers (18.5 miles) in diameter. The impact excavated into Europa's icy crust, throwing debris (seen as whitish material) across the surrounding terrain. Also visible is a dark band, named Belus Linea, extending east-west across the image. This type of feature, which scientists call a 'triple band,' is characterized by a bright stripe down the middle. The outer margins of this and other triple bands are diffuse, suggesting that the dark material was put there as a result of possible geyser-like activity which shot gas and rocky debris from Europa's interior. The curving 'X' pattern seen in the lower left corner of the image appears to represent fracturing of the icy crust and infilling by slush which froze in place. The crater is centered at about 2 degrees north latitude by 239 degrees west longitude. The image was taken from a distance of 156,000 kilometers (about 96,300 miles) on June 27, 1996, during Galileo's first orbit around Jupiter. The area shown is 860 by 700 kilometers (530 by 430 miles), or about the size of Oregon and Washington combined. The Galileo mission is managed by NASA's Jet Propulsion Laboratory.

  2. The Europa Ocean Discovery mission

    SciTech Connect

    Edwards, B.C.; Chyba, C.F.; Abshire, J.B.

    1997-06-01

    Since it was first proposed that tidal heating of Europa by Jupiter might lead to liquid water oceans below Europa`s ice cover, there has been speculation over the possible exobiological implications of such an ocean. Liquid water is the essential ingredient for life as it is known, and the existence of a second water ocean in the Solar System would be of paramount importance for seeking the origin and existence of life beyond Earth. The authors present here a Discovery-class mission concept (Europa Ocean Discovery) to determine the existence of a liquid water ocean on Europa and to characterize Europa`s surface structure. The technical goal of the Europa Ocean Discovery mission is to study Europa with an orbiting spacecraft. This goal is challenging but entirely feasible within the Discovery envelope. There are four key challenges: entering Europan orbit, generating power, surviving long enough in the radiation environment to return valuable science, and complete the mission within the Discovery program`s launch vehicle and budget constraints. The authors will present here a viable mission that meets these challenges.

  3. Short-term risk of anaemia following initiation of combination antiretroviral treatment in HIV-infected patients in countries in sub-Saharan Africa, Asia-Pacific, and central and South America

    PubMed Central

    2012-01-01

    Background The objective was to examine the short-term risk and predictors of anaemia following initiation of combination antiretroviral therapy (cART) in HIV-infected patients from the Western Africa, Eastern Africa, Southern Africa, Central Africa, Asian-Pacific, and Caribbean and Central and South America regions of the International Epidemiologic Databases to Evaluate AIDS (IeDEA) collaboration. Methods Anaemia was defined as haemoglobin of < 10 g/dL. Patients were included if they started cART with three or more drugs, had prior haemoglobin of > = 10 g/dL, and had one or more follow-up haemoglobin tests. Factors associated with anaemia up to 12 months were examined using Cox proportional hazards models and stratified by IeDEA region. Results Between 1998 and 2008, 19,947 patients initiated cART with baseline and follow-up haemoglobin tests (7358, 7289, 2853, 471, 1550 and 426 in the Western Africa, Eastern Africa, Southern Africa, Central Africa, Asian-Pacific, and Caribbean and Central and South America regions, respectively). At initiation, anaemia was found in 45% of Western Africa patients, 29% of Eastern Africa patients, 21% of Southern Africa patients, 36% of Central Africa patients, 15% of patients in Asian-Pacific and 14% of patients in Caribbean and Central and South America. Among patients with haemoglobin of > = 10 g/dL at baseline (13,445), the risks of anaemia were 18.2, 6.6, 9.7, 22.9, 11.8 and 19.5 per 100 person-years in the Western Africa, Eastern Africa, Southern Africa, Central Africa, Asian, and Caribbean and Central and South America regions, respectively. Factors associated with anaemia were female sex, low baseline haemoglobin level, low baseline CD4 count, more advanced disease stage, and initial cART containing zidovudine. Conclusions In data from 34 cohorts of HIV-infected patients from sub-Saharan Africa, Central and South America, and Asia, the risk of anaemia within 12 months of initiating cART was moderate. Routine haemoglobin

  4. Habitability Of Europa's Crust

    NASA Astrophysics Data System (ADS)

    Greenberg, R.; Tufts, B. R.; Geissler, P.; Hoppa, G.

    Physical characterization of Europa's crust shows it to be rich in potentially habitable niches, with several timescales for change that would allow stability for organisms to prosper and still require and drive evolution and adaptation. Studies of tectonics on Europa indicate that tidal stress causes much of the surface cracking, that cracks pen- etrate through to liquid water (so the ice must be thin), and that cracks continue to be worked by tidal stress. Thus a global ocean is (or was until recently) well linked to the surface. Daily tidal flow (period~days) transports substances up and down through the active cracks, mixing surface oxidants and fuels (cometary material) with the oceanic reservoir of endogenic and exogenic substances. Organisms moving with the flow or anchored to the walls could exploit the disequilibrium chemistry, and those within a few meters of the surface could photosynthesize. Cracks remain active for at least ~10,000 yr, but deactivate as nonsynchronous rotation moves them to different stress regimes in less than a million yr. Thus, to survive, organisms squeezed into the ocean must migrate to new cracks, and those frozen in place must hibernate. Most sites remelt and would release captive organisms within about a million yr based on the prevalence of chaotic terrain, which covers nearly half of Europa. Linkage of the ocean to the surface also could help sustain life in the ocean by delivering oxidants and fuels. Suboceanic volcanism (if any) could provide additional sites and support for life, but is not necessary. Recent results support this model. We further constrain the non-synchronous rotation rate, demonstrate the plausibility of episodic melt-through, show that characteristics of pits and uplift features do not imply thick ice, and demonstrate polar wander, i.e. that the ice crust is detached from the solid interior and has slipped as a unit relative to the spin axis. Thus Europa's biosphere (habitable if not inhabited) likely

  5. Mars, Europa and beyond

    NASA Astrophysics Data System (ADS)

    Rummel, J. D.

    2004-07-01

    The two other solar system bodies thought to be most compatible with "life as we know it" are the planet Mars and Europa, a natural satellite of the planet Jupiter. These worlds appear to harbor the potential for past and/or present-day liquid water, biologically useful energy sources, and a significant and rich organic chemistry. Such traits are under active investigation both through ongoing, targeted, solar system exploration missions and from the extensive analysis of data from previous missions and astronomical observations. And both bodies are the subject of astrobiologically inspired future missions. The nature of both Mars and Europa fuels speculation about the prospects for life, and the established facts about each of them, added to more recent observations, can explain their astrobiological interest. Nonetheless, such data can only form a circumstantial case for that interest, and further investigations of water (in all of its forms), energy, and organic chemistry are sure to be required before astrobiological investigations can be further targeted-and data from any biological observations can be properly interpreted. Most important will be a dedication to understanding both Mars and Europa for the environments that they possess-and the nature and distribution of those environments in space and time-rather than trying to understand these worlds by simple analogy to the modern Earth. It is clear that both Mars and Europa have characteristics that may be similar to those of Earth when studied over its entire history, but it is equally true that each of them have characteristics that are unlike anything presented by the Earth system at any single time in its past. The same can be said of Saturn's moon, Titan, which presents a compelling mix of organic chemistry, water ice, and atmosphere-but must represent a significant departure from any historical Earth. This is not necessarily a disadvantage. In fact, through the study of Mars, Europa, and Titan we may

  6. [JSPS Asia and Africa scientific platform program development for the medicinal chemistry based on biologically active natural products in the subtropical zone].

    PubMed

    Saito, Naoki; Morita, Takashi

    2009-04-01

    In 2005, the independent administrative institution the "Japan Society for the Promotion of Sciences (JSPS)" initiated the "Asia and Africa Science Platform Program", which is a new project aimed to create high potential research hubs in selected fields within the Asian and African region, while fostering the next generation of leading researchers. Another goal is to establish sustainable collaborative relationships among universities and research institutes in Japan and other Asian and African countries. In this project, we consider natural sources existing in partner countries to be the most important factor in the production of medicine. We will search for target compounds and analyze their structures by screening biologically active natural products. Additionally, we will design functional molecules and create process for retrieving a large supply of target compounds based on a bioprospecting strategy. Thailand, Indonesia, and India share the vision of enhancing collaborative efforts. By conducting this researche, we will focus on academic research that is necessary for the development of the pharmaceutical and medical products industry in partner countries. There are four selected research topics as followeds: 1) Development of New Antitumor Agents based on Marine Natural Products; 2) Development of New Anticoagulants and Anti-VEGF; 3) Molecular Epidemiological Investigation of Emerging Infectious Diseases and Development of Novel Diagnosis and Therapeutic Agents; and 4) Medicinal Chemistry on Biologically Active Natural Products from the Traditional Condiments and Medicines. The exchanges might take the form of joint research seminars. The first Medicinal Chemistry Seminar of the AA Scientific Platform Program was co-organized with the 23th Annual Research Conference on Pharmaceutical Sciences, Thailand at Chulalongkorn University, Bangkok, on December 14-15, 2006. The 2nd JSPS seminar was co-organized with the 1st Bioactive Natural Products from Marine

  7. Geologic mapping of Europa

    USGS Publications Warehouse

    Greeley, R.; Figueredo, P.H.; Williams, D.A.; Chuang, F.C.; Klemaszewski, J.E.; Kadel, S.D.; Prockter, L.M.; Pappalardo, R.T.; Head, J. W., III; Collins, G.C.; Spaun, N.A.; Sullivan, R.J.; Moore, Johnnie N.; Senske, D.A.; Tufts, B.R.; Johnson, T.V.; Belton, M.J.S.; Tanaka, K.L.

    2000-01-01

    Galileo data enable the major geological units, structures, and surface features to be identified on Europa. These include five primary units (plains, chaos, band, ridge, and crater materials) and their subunits, along with various tectonic structures such as faults. Plains units are the most widespread. Ridged plains material spans a wide range of geological ages, including the oldest recognizable features on Europa, and appears to represent a style of tectonic resurfacing, rather than cryovolcanism. Smooth plains material typically embays other terrains and units, possibly as a type of fluid emplacement, and is among the youngest material units observed. At global scales, plains are typically mapped as undifferentiated plains material, although in some areas differences can be discerned in the near infrared which might be related to differences in ice grain size. Chaos material is composed of plains and other preexisting materials that have been severely disrupted by inferred internal activity; chaos is characterized by blocks of icy material set in a hummocky matrix. Band material is arrayed in linear, curvilinear, wedge-shaped, or cuspate zones with contrasting albedo and surface textures with respect to the surrounding terrain. Bilateral symmetry observed in some bands and the relationships with the surrounding units suggest that band material forms by the lithosphere fracturing, spreading apart, and infilling with material derived from the subsurface. Ridge material is mapped as a unit on local and some regional maps but shown with symbols at global scales. Ridge material includes single ridges, doublet ridges, and ridge complexes. Ridge materials are considered to represent tectonic processes, possibly accompanied by the extrusion or intrusion of subsurface materials, such as diapirs. The tectonic processes might be related to tidal flexing of the icy lithosphere on diurnal or longer timescales. Crater materials include various interior (smooth central

  8. Geologic mapping of Europa

    NASA Astrophysics Data System (ADS)

    Greeley, Ronald; Collins, Geoffrey C.; Spaun, Nicole A.; Sullivan, Robert J.; Moore, Jeffrey M.; Senske, David A.; Tufts, B. Randall; Johnson, Torrence V.; Belton, Michael J. S.; Tanaka, Kenneth L.

    2000-09-01

    Galileo data enable the major geological units, structures, and surface features to be identified on Europa. These include five primary units (plains, chaos, band, ridge, and crater materials) and their subunits, along with various tectonic structures such as faults. Plains units are the most widespread. Ridged plains material spans a wide range of geological ages, including the oldest recognizable features on Europa, and appears to represent a style of tectonic resurfacing, rather than cryovolcanism. Smooth plains material typically embays other terrains and units, possibly as a type of fluid emplacement, and is among the youngest material units observed. At global scales, plains are typically mapped as undifferentiated plains material, although in some areas differences can be discerned in the near infrared which might be related to differences in ice grain size. Chaos material is composed of plains and other preexisting materials that have been severely disrupted by inferred internal activity; chaos is characterized by blocks of icy material set in a hummocky matrix. Band material is arrayed in linear, curvilinear, wedge-shaped, or cuspate zones with contrasting albedo and surface textures with respect to the surrounding terrain. Bilateral symmetry observed in some bands and the relationships with the surrounding units suggest that band material forms by the lithosphere fracturing, spreading apart, and infilling with material derived from the subsurface. Ridge material is mapped as a unit on local and some regional maps but shown with symbols at global scales. Ridge material includes single ridges, doublet ridges, and ridge complexes. Ridge materials are considered to represent tectonic processes, possibly accompanied by the extrusion or intrusion of subsurface materials, such as diapirs. The tectonic processes might be related to tidal flexing of the icy lithosphere on diurnal or longer timescales. Crater materials include various interior (smooth central

  9. The ice plumes of Europa

    NASA Astrophysics Data System (ADS)

    Sparks, William

    2014-10-01

    It is of extreme interest to NASA and the scientific community that evidence has been found for plumes of water ice venting from the polar regions of Europa (Roth et al 2014) - spectroscopic detection of off-limb line emission from the dissociation products of water. We were awarded Cycle 21 time to seek direct images of the Europa exosphere, including Enceladus-like plumes if present, basing our study on FUV images of Europa as it transits the smooth face of Jupiter. We also obtained a necessary FUV image of Europa out of transit. These observations provide additional evidence for the presence of ice plumes on Europa. Here, we propose to augment our previous imaging work and to seek an initial, efficient characterization of off-limb emission as Europa orbits Jupiter. Such images provide sensitive flux and column density limits, with exceptional spatial resolution. In transit, our strategy can place firm limits on, or measurements of, absorbing columns, their distribution with altitude above the surface of Europa, and constrain their wavelength dependence and hence composition. Out of transit, geometrical and surface brightness considerations can help us distinguish between continuum FUV emission from forward- or back-scattering, from line emission, or, though we might prefer otherwise, from more subtle instrumental artifacts than hitherto understood. If the ice fountains of Europa arise from the deep ocean, we have gained access to probably the most astrobiologically interesting location in the Solar System.

  10. To Land on Europa

    NASA Technical Reports Server (NTRS)

    Shirley, James H.; Carlson, Robert W.; Zimmerman, Wayne F.; Rivellini, Tommaso P.; Sabahi, Dara

    2005-01-01

    The Science Definition Team (SDT) for NASA's Jupiter Icy Moons Orbiter (JIMO) Mission recommends including a lander as an integral part of the science payload of the JIMO Mission. The Europa Surface Science Package (ESSP) could comprise up to 25% of science payload resources. We have identified several key scientific and technical issues for such a lander, including 1) the potential effects of propellant contamination of the landng site, 2) the likely macroscopic surface roughness of potential landing sites, and 3) the desire to sample materials from depths of approximately 1 m beneath the surface. Discussion and consensus building on these issues within the science community is a prerequisite for establishing design requirements.

  11. Global Health Donor Presence, Variations in HIV/AIDS Prevalence, and External Resources for Health in Developing Countries in Africa and Asia

    PubMed Central

    Azuine, Romuladus Emeka; Singh, Gopal K.; Ekejiuba, Sussan E.; Ashu, Eta; Azuine, Magnus A.

    2014-01-01

    Objective: The presence of multiple global health aid organizations in donor recipient countries at any point in time has led to arguments for and against aid coordination and aid pluralism. Little data, however, exist to empirically demonstrate the relationship between donor presence and longitudinal disease outcomes in donor-recipient countries. We examined the association between global health donor presence and changes in HIV/AIDS prevalence in 14 developing countries: 12 in Africa (Ethiopia, Kenya, Tanzania, Malawi, Zimbabwe, Mozambique, Rwanda, South Africa, Uganda, Zambia, Burkina Faso and Mali) and compared them with two developing countries in Asia (India and Vietnam). Methods: To conduct our analyses, we conceptualized a framework for examining global health donor presence and disease outcomes. Donor presence data were derived from Mapping the Donor Landscape in Global Health: HIV/AIDS, a report published by the Kaiser Family Foundation, Washington, DC, USA. HIV/AIDS prevalence data were obtained and analyzed from the World Health Statistics and the Demographic and Health Surveys. Percent changes in national HIV/AIDS prevalence between 2009 and 2011 in the 14 developing countries were computed and correlation coefficients between donor presence and prevalence changes were calculated. Results: Between 2009 and 2011, HIV/AIDS prevalence decreased in all but one of the 14 developing countries with the presence of 21 or more global health donors. There was about 40% overall reduction in HIV/AIDS prevalence across the 14 countries in our analyses. South Africa recorded the most reduction in HIV/AIDS prevalence (-6.7%) followed by Zambia (-6.3, %), and Mozambique (-5.7%). Ethiopia was the only country without a reduction in HIV/AIDS prevalence (+0.1%). A correlation coefficient of 0.43 implied greater reductions in HIV/AIDS prevalence associated with increased donor presence. Conclusions and Public Health Implications: Our study shows a correlation between

  12. Europa's Salty Surface

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    1998-09-01

    Pictures of Jupiter's moon Europa taken by the Galileo spacecraft during the past couple of years have suggested to scientists that there is now, or was in the past, an ocean beneath the satellite's frozen crust. Now a team from the University of Hawaii, the Jet Propulsion Laboratory, the U.S. Geological Survey, and STI Inc. may have given us our first glimpse at the chemical composition of that ocean. Using data obtained by the Near-Infrared Mapping Spectrometer (NIMS) carried by Galileo, Thomas McCord (U. Hawaii) and his colleagues examined darker regions on the surface and compared the spacecraft data to numerous chemical compounds. Their analysis indicates that the darker areas are most likely composed of deposits of salty minerals such as sulfates and carbonates. McCord and his associates believe that the minerals formed when ocean water erupted onto the surface and then evaporated, leaving behind salty deposits. They hope that further research will allow them to determine the chemical composition of Europa's hidden ocean and assess the likelihood that life could have formed in it.

  13. Europa Ice Rafts

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This high resolution image shows the ice-rich crust of Europa, one of the moons of Jupiter. Seen here are crustal plates ranging up to 13 kilometers (8 miles) across, which have been broken apart and 'rafted' into new positions, superficially resembling the disruption of pack-ice on polar seas during spring thaws on Earth. The size and geometry of these features suggest that motion was enabled by ice-crusted water or soft ice close to the surface at the time of disruption.

    The area shown is about 34 kilometers by 42 kilometers (21 miles by 26 miles), centered at 9.4 degrees north latitude, 274 degrees west longitude, and the resolution is 54 meters (59 yards). This picture was taken by the Solid State Imaging system on board the Galileo spacecraft on February 20, 1997, from a distance of 5,340 kilometers (3,320 miles) during the spacecraft's close flyby of Europa.

    The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington D.C. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at: http://galileo.jpl.nasa.gov.

  14. Europa's Leading Hemisphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image of Europa's leading hemisphere was obtained by the solid state imaging (CCD) system on board NASA's Galileo spacecraft during its seventh orbit of Jupiter. In the upper left part of the image is Tyre, a multi-ringed structure that may have formed as a result of an ancient impact. Also visible are numerous lineaments that extend for over 1000 kilometers. The limb, or edge, of Europa in this image can be used by scientists to constrain the radius and shape of the satellite. North is to the top of the picture and the sun illuminates the surface from the right. The image, centered at -40 latitude and 180 longitude, covers an area approximately 2000 by 1300 kilometers. The finest details that can be discerned in this picture are about 6.6 kilometers across. The images were taken on April 3, 1997 at 17 hours, 42 minutes, 19 seconds Universal Time when the spacecraft was at a range of 31,8628 kilometers.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  15. Reaching the poor with health interventions: programme-incidence analysis of seven randomised trials of women's groups to reduce newborn mortality in Asia and Africa

    PubMed Central

    Houweling, Tanja A J; Morrison, Joanna; Alcock, Glyn; Azad, Kishwar; Das, Sushmita; Hossen, Munir; Kuddus, Abdul; Lewycka, Sonia; Looman, Caspar W; Magar, Bharat Budhathoki; Manandhar, Dharma S; Akter, Mahfuza; Dube, Albert Lazarous Nkhata; Rath, Shibanand; Saville, Naomi; Sen, Aman; Tripathy, Prasanta; Costello, Anthony

    2016-01-01

    Background Efforts to end preventable newborn deaths will fail if the poor are not reached with effective interventions. To understand what works to reach vulnerable groups, we describe and explain the uptake of a highly effective community-based newborn health intervention across social strata in Asia and Africa. Methods We conducted a secondary analysis of seven randomised trials of participatory women's groups to reduce newborn mortality in India, Bangladesh, Nepal and Malawi. We analysed data on 70 574 pregnancies. Socioeconomic and sociodemographic differences in group attendance were tested using logistic regression. Qualitative data were collected at each trial site (225 focus groups, 20 interviews) to understand our results. Results Socioeconomic differences in women's group attendance were small, except for occasional lower attendance by elites. Sociodemographic differences were large, with lower attendance by young primigravid women in African as well as in South Asian sites. The intervention was considered relevant and interesting to all socioeconomic groups. Local facilitators ensured inclusion of poorer women. Embarrassment and family constraints on movement outside the home restricted attendance among primigravid women. Reproductive health discussions were perceived as inappropriate for them. Conclusions Community-based women's groups can help to reach every newborn with effective interventions. Equitable intervention uptake is enhanced when facilitators actively encourage all women to attend, organise meetings at the participants’ convenience and use approaches that are easily understandable for the less educated. Focused efforts to include primigravid women are necessary, working with families and communities to decrease social taboos. PMID:26246540

  16. Modeling the Europa plasma torus

    NASA Technical Reports Server (NTRS)

    Schreier, Ron; Eviatar, Aharon; Vasyliunas, Vytenis M.; Richardson, John D.

    1993-01-01

    The existence of a torus of plasma generated by sputtering from Jupiter's satellite Europa has long been suspected but never yet convincingly demonstrated. Temperature profiles from Voyager plasma observations indicate the presence of hot, possibly freshly picked-up ions in the general vicinity of the orbit of Europa, which may be interpreted as evidence for a local plasma torus. Studies of ion partitioning in the outer regions of the Io torus reveal that the oxygen to sulfur mixing ratio varies with radial distance; this may indicates that oxygen-rich matter is injected from a non-Io source, most probably Europa. We have constructed a quantitative model of a plasma torus near the orbit of Europa which takes into account plasma input from the Io torus, sputtering from the surface of Europa, a great number of ionization and charge exchange processes, and plasma loss by diffusive transport. When the transport time is chosen so that the model's total number density in consistent with the observed total plasma density, the contribution from Europa is found to be significant although not dominant. The model predicts in detail the ion composition, charge states, and the relative fractions of hot Europa-generated and (presumed) cold Io-generated ions. The results are generally consistent with observations from Voyager and can in principle (subject to limitations of data coverage) be confirmed in more detail by Ulysses.

  17. Akon - A Penetrator for Europa

    NASA Astrophysics Data System (ADS)

    Jones, Geraint

    2016-04-01

    Jupiter's moon Europa is one of the most intriguing objects in our Solar System. This 2000km-wide body has a geologically young solid water ice crust that is believed to cover a global ocean of liquid water. The presence of this ocean, together with a source of heating through tidal forces, make Europa a conceivable location for extraterrestrial life. The science case for exploring all aspects of this icy world is compelling. NASA has selected the Europa Mission (formerly Europa Clipper) to study Europa in detail in the 2020s through multiple flybys, and ESA's JUICE mission will perform two flybys of the body in the 2030s. The US agency has extended to the European Space Agency an invitation to provide a contribution to their mission. European scientists interested in Europa science and exploration are currently organizing themselves, in the framework of a coordinated Europa M5 Inititative to study concurrently the main options for this ESA contribution, from a simple addition of individual instruments to the NASA spacecraft, to a lander to investigate Europa's surface in situ. A high speed lander - a penetrator - is by far the most promising technology to achieve this latter option within the anticipated mass constraints, and studies of such a hard lander, many funded by ESA, are now at an advanced level. An international team to formally propose an Europa penetrator to ESA in response to the anticipated ESA M5 call is growing. The working title of this proposal is Akon (Άκων), named after the highly accurate javelin gifted to Europa by Zeus in ancient Greek mythology. We present plans for the Akon penetrator, which would impact Europa's surface at several hundred metres per second, and travel up to several metres into the moon's subsurface. To achieve this, the penetrator would be delivered to the surface by a dedicated descent module, to be destroyed on impact following release of the penetrator above the surface. It is planned that the instruments to be

  18. On the habitability of Europa

    NASA Technical Reports Server (NTRS)

    Reynolds, R. T.; Squyres, S. W.; Colburn, D. S.; Mckay, C. P.

    1983-01-01

    It is pointed out that the Voyager flybys of Jupiter produced remarkable images of Europa, one of the four large Galilean satellites. Taking into account information provided by these Voyagers flybys and other data and investigations, a study is conducted regarding the suitability of Europa as a habitat for living organisms. The performed calculations indicate, that for a plausible physical model of Europa, the general conditions for the survival of biological organisms could exist, at least in some regions, highly restricted in both space and time.

  19. Dark Bands on Europa

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Dark crisscrossing bands on Jupiter's moon Europa represent widespread disruption from fracturing and the possible eruption of gases and rocky material from the moon's interior in this four-frame mosaic of images from NASA's Galileo spacecraft. These and other features suggest that soft ice or liquid water was present below the ice crust at the time of disruption. The data do not rule out the possibility that such conditions exist on Europa today. The pictures were taken from a distance of 156,000 kilometers (about 96,300 miles) on June 27, 1996. Many of the dark bands are more than 1,600 kilometers (1,000 miles) long, exceeding the length of the San Andreas fault of California. Some of the features seen on the mosaic resulted from meteoritic impact, including a 30- kilometer (18.5 mile) diameter crater visible as a bright scar in the lower third of the picture. In addition, dozens of shallow craters seen in some terrains along the sunset terminator zone (upper right shadowed area of the image) are probably impact craters. Other areas along the terminator lack craters, indicating relatively youthful surfaces, suggestive of recent eruptions of icy slush from the interior. The lower quarter of the mosaic includes highly fractured terrain where the icy crust has been broken into slabs as large as 30 kilometers (18.5 miles) across. The mosaic covers a large part of the northern hemisphere and includes the north pole at the top of the image. The sun illuminates the surface from the left. The area shown is centered on 20 degrees north latitude and 220 degrees west longitude and is about as wide as the United States west of the Mississippi River. The Galileo mission is managed by NASA's Jet Propulsion Laboratory.

  20. Europa Under Stress

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This high resolution image of the icy plains on Europa shows multiple sets of cross-cutting ridges. Many of these ridges are cut by younger fractures. Fractures that display relative motion are known as faults; several faults showing horizontal motion, like the San Andreas Fault in California, are seen here.

    Faults and ridges give planetary geologists clues to the stresses within the crust at the time of formation. Ridges typically form as a result of compression. The orientation of the compressive stress is perpendicular to the strike (long axis) of the ridge. In contrast, fractures form as a result of tensional stresses that crack the brittle crust. These features indicate that the surface of Europa has experienced repeated episodes of tension and compression throughout its history.

    This image is approximately 12 kilometers (7 miles) by 15 kilometers (9 miles) across, centered near 15N, 273W. The Galileo spacecraft obtained this image on February 20, 1997 during its sixth orbit of Jupiter from a distance of 2000 kilometers (1240 miles). North is toward the top of the image, with the sun illuminating the surface from the right.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  1. Small Craters on Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This high resolution view of the Conamara Chaos region on Jupiter's icy moon, Europa, reveals craters which range in size from about 30 meters to over 450 meters (slightly over a quarter of a mile) in diameter. The large number of craters seen here is unusual for Europa. This section of Conamara Chaos lies inside a bright ray of material which was ejected by the large impact crater, Pwyll, 1000 kilometers (620 miles) to the south. The presence of craters within the bright ray suggests that many are secondaries which formed from chunks of material that were thrown out by the enormous energy of the impact which formed Pwyll.

    North is to the upper right of the picture and the sun illuminates the surface from the east. The image, centered at 9 degrees latitude and 274 degrees longitude, covers an area approximately 8 by 4 kilometers (5 by 2.5 miles). The finest details that can be discerned in this picture are about 20 meters (66 feet) across. The images were taken on December 16, 1997 at a range of 960 kilometers (590 miles) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  2. Return to Europa: Overview of the Jupiter Europa orbiter mission

    NASA Astrophysics Data System (ADS)

    Clark, K.; Boldt, J.; Greeley, R.; Hand, K.; Jun, I.; Lock, R.; Pappalardo, R.; van Houten, T.; Yan, T.

    2011-08-01

    Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, the Galileo spacecraft supplied fascinating new insights into this satellite of Jupiter. Now, an international team is proposing a return to the Jupiter system and Europa with the Europa Jupiter System Mission (EJSM). Currently, NASA and ESA are designing two orbiters that would explore the Jovian system and then each would settle into orbit around one of Jupiter's icy satellites, Europa and Ganymede. In addition, the Japanese Aerospace eXploration Agency (JAXA) is considering a Jupiter magnetospheric orbiter and the Russian Space Agency is investigating a Europa lander.The Jupiter Europa Orbiter (JEO) would be the NASA-led portion of the EJSM; JEO would address a very important subset of the complete EJSM science objectives and is designed to function alone or in conjunction with ESA's Jupiter Ganymede Orbiter (JGO). The JEO mission concept uses a single orbiter flight system that would travel to Jupiter by means of a multiple-gravity-assist trajectory and then perform a multi-year study of Europa and the Jupiter system, including 30 months of Jupiter system science and a comprehensive Europa orbit phase of 9 months.The JEO mission would investigate various options for future surface landings. The JEO mission science objectives, as defined by the international EJSM Science Definition Team, include:Europa's ocean: Characterize the extent of the ocean and its relation to the deeper interior.Europa's ice shell: Characterize the ice shell and any subsurface water, including their heterogeneity, and the nature of surface-ice-ocean exchange.Europa's chemistry: Determine global surface compositions and chemistry, especially as related to habitability.Europa's geology: Understand the formation of surface features, including sites of recent or current activity, and identify and characterize candidate sites for future in situ

  3. Prioritizing action on health inequities in cities: An evaluation of Urban Health Equity Assessment and Response Tool (Urban HEART) in 15 cities from Asia and Africa.

    PubMed

    Prasad, Amit; Kano, Megumi; Dagg, Kendra Ann-Masako; Mori, Hanako; Senkoro, Hawa Hamisi; Ardakani, Mohammad Assai; Elfeky, Samar; Good, Suvajee; Engelhardt, Katrin; Ross, Alex; Armada, Francisco

    2015-11-01

    Following the recommendations of the Commission on Social Determinants of Health (2008), the World Health Organization (WHO) developed the Urban Health Equity Assessment and Response Tool (HEART) to support local stakeholders in identifying and planning action on health inequities. The objective of this report is to analyze the experiences of cities in implementing Urban HEART in order to inform how the future development of the tool could support local stakeholders better in addressing health inequities. The study method is documentary analysis from independent evaluations and city implementation reports submitted to WHO. Independent evaluations were conducted in 2011-12 on Urban HEART piloting in 15 cities from seven countries in Asia and Africa: Indonesia, Iran, Kenya, Mongolia, Philippines, Sri Lanka, and Vietnam. Local or national health departments led Urban HEART piloting in 12 of the 15 cities. Other stakeholders commonly engaged included the city council, budget and planning departments, education sector, urban planning department, and the Mayor's office. Ten of the 12 core indicators recommended in Urban HEART were collected by at least 10 of the 15 cities. Improving access to safe water and sanitation was a priority equity-oriented intervention in 12 of the 15 cities, while unemployment was addressed in seven cities. Cities who piloted Urban HEART displayed confidence in its potential by sustaining or scaling up its use within their countries. Engagement of a wider group of stakeholders was more likely to lead to actions for improving health equity. Indicators that were collected were more likely to be acted upon. Quality of data for neighbourhoods within cities was one of the major issues. As local governments and stakeholders around the world gain greater control of decisions regarding their health, Urban HEART could prove to be a valuable tool in helping them pursue the goal of health equity. PMID:26456133

  4. Molecular epidemiology and type-specific detection of echovirus 11 isolates from the Americas, Europe, Africa, Australia, southern Asia and the Middle East.

    PubMed

    Oberste, M Steven; Nix, William A; Kilpatrick, David R; Flemister, Mary R; Pallansch, Mark A

    2003-02-01

    Echovirus 11 (E11) is among the most commonly isolated human enteroviruses. To examine the range of genetic variation within the E11 serotype, we determined the complete VP1 sequences for 53 geographically dispersed E11 strains isolated in 16 countries from 1953 to 2001. E11 sequences were monophyletic with respect to all other enterovirus serotypes. The sequences clustered into four monophyletic genogroups, A-D; members of each genogroup differed from one another by <20%. Isolates in different genogroups differed from one another by 19-28%. The E11 prototype strain, USA/CA53-Gregory, was the sole member of genogroup B. All recent US isolates were members of one of two discrete lineages within genogroup D. The well-characterized E11 antigenic variant, USA/CA63-Silva, was also a member of genogroup D. Members of genogroups A and C were antigenically similar to USA/CA53-Gregory, as measured by neutralization with anti-Gregory and anti-Silva antisera. Only USA/CA63-Silva was neutralized more efficiently by the anti-Silva antiserum; other genogroup D viruses were Gregory-like or intermediate in their neutralization phenotype. Recent non-US isolates were distributed in genogroups A, C and D. Sequence similarities among genogroup D isolates from North America, Europe, Asia, Australia and North Africa demonstrate that an E11 strain can spread rapidly over a wide geographic area. The aligned sequences were used to develop an E11-specific RT-PCR assay, using degenerate, inosine-containing primers, to amplify all members of all genogroups. PMID:12573503

  5. Life on Europa?

    NASA Astrophysics Data System (ADS)

    Shylaja, B. S.

    1997-06-01

    The notion of life has always fascinated curious minds. From prehistoric days, fancy voyages to other colonies and visits from non-earthly beings have been creatively imagined. Apart from science fictions, the last few centuries saw many observational investigations of "cities of Moon", "colonies of Mars" and so on. However, the sophisticated tools of the modern era quickly put a full stop to these developments revealing that the other planets are not hospitable, and infact hostile for a life form like ours to exist there. That explains why in the last few decades the efforts shifted to observing the satellites of large planets. The anxiety grew with the knowledge of their atmospheric structure, chemical composition and volcanic activity. Detection of water, albeit frozen, was a welcome surprise. The flyby of Voyager and Pioneer provided ample evidence for the presence of water, one of the most important ingredients for the germination of the seed of life. The detection of the fossil of a microorganism on a stone believed to have fallen from Mars, boosted the scientists zeal to pursue the research, although the date for life on Mars (more than 3 billion years ago) is not very convincing. Last year, many scientists, from different branches like astrophysics, geology, oceanography, biology and astrogeology discussed the possibilities of life elsewhere in the universe. The focal point was not Mars, but Europa, one of the Galilean satellites of Jupiter. Their studies based on Voyager images supported the possibility of liquid water beneath the frozen sheets of ice. However, heat is also an essential parameter. Europa, being at a distance five times the sun-earth separation can have only 1/25th the warmth of the earth. Then, where does it get the necessary warmth from? There are other important sources of heat in many of these satellites that lie concealed from our view. They are the volcanoes. If present, can these keep the water warm below the ice sheets? The unmanned

  6. Europa Hemispherical Globes

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The images used for the base of this globe were chosen from coverage supplied by the Galileo solid-state imaging (SSI) camera and Voyager 1 and 2 spacecraft. The individual images were radiometrically calibrated and photometrically normalized using a Lunar-Lambert function with empirically derived values. A linear correction based on the statistics of all overlapping areas was then applied to minimize image brightness variations. The image data were selected on the basis of overall image quality, reasonable original input resolution (from 20 km/pixel for gap fill to as much as 200 m/pixel), and availability of moderate emission/incidence angles for topography. Although consistency was achieved where possible, different filters were included for global image coverage as necessary: clear/blue for Voyager 1 and 2, and clear, near-IR (757 nm), and green (559 nm) for Galileo SSI. Individual images were projected to a Sinusoidal Equal-Area projection at an image resolution of 500 m/pixel, and a final global mosaic was constructed in this same Sinusoidal projection.

    The global mosaic was then reprojected so that the entire surface of Europa is portrayed in a manner suitable for the production of a globe. A specialized program was used to create the 'flower petal' appearance of the images; the area of each petal from 0 to 75 degrees latitude is in the Transverse Mercator projection, and the area from 75 to 90 degrees latitude is in the Lambert Azimuthal Equal-Area projection. The projections for adjacent petals overlap by 2 degrees of longitude, so that some features are shown twice.

    Names shown on the globe are approved by the International Astronomical Union. The number, size, and placement of text were chosen for a 9-inch globe. A complete list of Europa nomenclature can be found at the Gazetteer of Planetary Nomenclature at http://planetarynames.wr.usgs.gov. The northern hemisphere is shown on the left, and the southern hemisphere is shown on the right.

  7. Folds on Europa

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This image, acquired by NASA's Galileo spacecraft on September 26, 1998, shows features on the surface of Jupiter's moon Europa that a scientific report published today interprets as signs of compressive folding.

    The imaged area is in the Astypalaea Linea region of Europa's southern hemisphere, seen with low-angle sunshine coming from the upper right. North is toward the top.

    Astypalaea Linea is the smooth, gray area that stretches from north to south across the image mosaic. It is thought to have formed by a combination of pulling apart and sliding of the icy surface. The telltale fold features are within the smoother portions of the surface between the more dominant ridges, which are attributed to upwelling of material through surface ice. In the smooth areas, the surface has gentle swells and dips, which show most clearly in the version on the right, processed to accentuate broader-scale shapes. For example, a dip about 15 kilometers (about 10 miles) wide cuts diagonally across the northern half of the largest smooth area, and a rise runs parallel to that in the southern half of the smooth area. closeup detail

    Louise M. Prockter, at Johns Hopkins University, and Robert T. Pappalardo, at Brown University, report in the journal Science today that those rises, or anticlines, and dips, or synclines, appear to be the result of compression causing the crust to fold.

    Additional evidence comes from smaller features more visible in the version on the left, covering the same area. At the crest of the gentle rise in the largest smooth area are small fractures that could be caused by the stretching stress of bending the surface layer upwards. Similarly, at the bottom of the adjacent dip are small, wrinkle-like ridges that could be caused by stress from bending the surface layer downwards.

    The Jet Propulsion Laboratory, Pasadena, Calif., manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California

  8. The Europa Clipper Mission Concept

    NASA Astrophysics Data System (ADS)

    Pappalardo, Robert; Goldstein, Barry; Magner, Thomas; Prockter, Louise; Senske, David; Paczkowski, Brian; Cooke, Brian; Vance, Steve; Wes Patterson, G.; Craft, Kate

    2014-05-01

    A NASA-appointed Science Definition Team (SDT), working closely with a technical team from the Jet Propulsion Laboratory (JPL) and the Applied Physics Laboratory (APL), recently considered options for a future strategic mission to Europa, with the stated science goal: Explore Europa to investigate its habitability. The group considered several mission options, which were fully technically developed, then costed and reviewed by technical review boards and planetary science community groups. There was strong convergence on a favored architecture consisting of a spacecraft in Jupiter orbit making many close flybys of Europa, concentrating on remote sensing to explore the moon. Innovative mission design would use gravitational perturbations of the spacecraft trajectory to permit flybys at a wide variety of latitudes and longitudes, enabling globally distributed regional coverage of the moon's surface, with nominally 45 close flybys at altitudes from 25 to 100 km. We will present the science and reconnaissance goals and objectives, a mission design overview, and the notional spacecraft for this concept, which has become known as the Europa Clipper. The Europa Clipper concept provides a cost-efficient means to explore Europa and investigate its habitability, through understanding the satellite's ice and ocean, composition, and geology. The set of investigations derived from the Europa Clipper science objectives traces to a notional payload for science, consisting of: Ice Penetrating Radar (for sounding of ice-water interfaces within and beneath the ice shell), Topographical Imager (for stereo imaging of the surface), ShortWave Infrared Spectrometer (for surface composition), Neutral Mass Spectrometer (for atmospheric composition), Magnetometer and Langmuir Probes (for inferring the satellite's induction field to characterize an ocean), and Gravity Science (to confirm an ocean).The mission would also include the capability to perform reconnaissance for a future lander

  9. Human Population Admixture in Asia

    PubMed Central

    2012-01-01

    Genetic admixture in human, the result of inter-marriage among people from different well-differentiated populations, has been extensively studied in the New World, where European colonization brought contact between peoples of Europe, Africa, and Asia and the Amerindian populations. In Asia, genetic admixing has been also prevalent among previously separated human populations. However, studies on admixed populations in Asia have been largely underrepresented in similar efforts in the New World. Here, I will provide an overview of population genomic studies that have been published to date on human admixture in Asia, focusing on population structure and population history. PMID:23166524

  10. Probing Europa's Interior with Natural Sound Sources

    NASA Astrophysics Data System (ADS)

    Makris, N. C.; Lee, S.; Zanolin, M.; Pappalardo, R. T.

    2003-03-01

    Our goal is to use acoustic echo-sounding and tomographic techniques to determine Europa's interior structure. We show that robust estimates can be made of Europa's ice layering structure and potential ocean depth with a single acoustic sensor.

  11. Europa Wedge Region

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This image shows an area of crustal separation on Jupiter's moon, Europa. Lower resolution pictures taken earlier in the tour of NASA's Galileo spacecraft revealed that dark wedge-shaped bands in this region are areas where the icy crust has completely pulled apart. Dark material has filled up from below and filled the void created by this separation.

    In the lower left corner of this image, taken by Galileo's onboard camera on December 16, 1997, a portion of one dark wedge area is visible, revealing a linear texture along the trend of the wedge. The lines of the texture change orientation slightly and reflect the fact that we are looking at a bend in the wedge. The older, bright background, visible on the right half of the image, is criss-crossed with ridges. A large, bright ridge runs east-west through the upper part of the image, cutting across both the older background plains and the wedge. This ridge is rough in texture, with numerous small terraces and troughs containing dark material.

    North is to the top of the picture and the sun illuminates the surface from the northwest. This image, centered at approximately 16.5 degrees south latitude and 196.5 degrees west longitude, covers an area approximately 10 kilometers square (about 6.5 miles square). The resolution of this image is about 26 meters per picture element. This image was taken by the solid state imaging system from a distance of 1250 kilometers (750 miles).

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  12. Europa's Pwyll Crater

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This view of the Pwyll impact crater on Jupiter's moon Europa taken by NASA's Galileo spacecraft shows the interior structure and surrounding ejecta deposits. Pwyll's location is shown in the background global view taken by Galileo's camera on December 16, 1997. Bright rays seen radiating from Pwyll in the global image indicate that this crater is geologically young. The rim of Pwyll is about 26 kilometers (16 miles) in diameter, and a halo of dark material excavated from below the surface extends a few kilometers beyond the rim. Beyond this dark halo, the surface is bright and numerous secondary craters can be seen. The closeup view of Pwyll, which combines imaging data gathered during the December flyby and the flyby of February 20, 1997, indicates that unlike most fresh impact craters, which have much deeper floors, Pwyll's crater floor is at approximately the same level as the surrounding background terrain.

    North is to the top of the picture and the sun illuminates the surface from the northeast. This closeup image, centered at approximately 26 degrees south latitude and 271 degrees west longitude, covers an area approximately 125 by 75 kilometers (75 by 45 miles). The finest details that can be discerned in this picture are about 250 meters (800 feet) across. This image was taken on at a range of 12,400 kilometers (7,400 miles), with the green filter of Galileo's solid state imaging system.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  13. Europa: Initial Galileo Geological Observations

    USGS Publications Warehouse

    Greeley, R.; Sullivan, R.; Klemaszewski, J.; Homan, K.; Head, J. W., III; Pappalardo, R.T.; Veverka, J.; Clark, B.E.; Johnson, T.V.; Klaasen, K.P.; Belton, M.; Moore, J.; Asphaug, E.; Carr, M.H.; Neukum, G.; Denk, T.; Chapman, C.R.; Pilcher, C.B.; Geissler, P.E.; Greenberg, R.; Tufts, R.

    1998-01-01

    Images of Europa from the Galileo spacecraft show a surface with a complex history involving tectonic deformation, impact cratering, and possible emplacement of ice-rich materials and perhaps liquids on the surface. Differences in impact crater distributions suggest that some areas have been resurfaced more recently than others; Europa could experience current cryovolcanic and tectonic activity. Global-scale patterns of tectonic features suggest deformation resulting from non-synchronous rotation of Europa around Jupiter. Some regions of the lithosphere have been fractured, with icy plates separated and rotated into new positions. The dimensions of these plates suggest that the depth to liquid or mobile ice was only a few kilometers at the time of disruption. Some surfaces have also been upwarped, possibly by diapirs, cryomagmatic intrusions, or convective upwelling. In some places, this deformation has led to the development of chaotic terrain in which surface material has collapsed and/or been eroded. ?? 1998 Academic Press.

  14. Epidemiology and integrated management of persistently transmitted aphid-borne viruses of legume and cereal crops in West Asia and North Africa.

    PubMed

    Makkouk, Khaled M; Kumari, Safaa G

    2009-05-01

    Cool-season food legumes (faba bean, lentil, chickpea and pea) and cereals (bread and durum wheat and barley) are the most important and widely cultivated crops in West Asia and North Africa (WANA), where they are the main source of carbohydrates and protein for the majority of the population. Persistently transmitted aphid-borne viruses pose a significant limitation to legume and cereal production worldwide. Surveys conducted in many countries in WANA during the last three decades established that the most important of these viruses are: Faba bean necrotic yellows virus (FBNYV: genus Nanovirus; family Nanoviridae), Bean leafroll virus (BLRV: genus Luteovirus; family Luteoviridae), Beet western yellows virus (BWYV: genus Polerovirus; family Luteoviridae), Soybean dwarf virus (SbDV: genus Luteovirus; family Luteoviridae) and Chickpea chlorotic stunt virus (CpCSV: genus Polerovirus; family Luteoviridae) which affect legume crops, and Barley yellow dwarf virus-PAV (BYDV-PAV: genus Luteovirus; family Luteoviridae), Barley yellow dwarf virus-MAV (BYDV-MAV: genus Luteovirus; family Luteoviridae) and Cereal yellow dwarf virus-RPV (CYDV-RPV: genus Polerovirus; family Luteoviridae) which affect cereal crops. Loss in yield caused by these viruses is usually high when infection occurs early in the growing season. Many aphid vector species for the above-mentioned viruses are reported to be prevalent in the WANA region. In addition, in this region many wild species (annual or perennial) were found infected with these viruses and may play an important role in their ecology and spread. Fast spread of these diseases was always associated with high aphid vector populations and activity. Although virus disease management can be achieved by combining several control measures, development of resistant genotypes is undoubtedly one of the most appropriate control methods. Over the last three decades barley and wheat genotypes resistant to BYDV, faba bean genotypes resistant to BLRV, and

  15. Transitioning toward Sustainable Development Goals: The Role of Household Environment in Influencing Child Health in Sub-Saharan Africa and South Asia Using Recent Demographic Health Surveys.

    PubMed

    Anand, Ankit; Roy, Nobhojit

    2016-01-01

    The Millennium Development Goals are now replaced by 17 sustainable development goals. The emphasis of old goals was on improving water, sanitation, and child mortality conditions in developing countries. The study explored the major question about the association between different household environment conditions with child survival and health in Sub-Saharan African and South Asian countries in the current scenario. This paper estimated the risk of death, morbidity, and undernutrition among children living in households with the improved sources of water, sanitation, and non-solid cooking fuel. Two sources of information are explored in this study. First, data from World Health Statistics (WHS)-2014 for all of the Sub-Saharan African and South Asian countries were used. Second, available standard Demographic and Health Survey (DHS) performed in the countries of Sub-Saharan Africa and South Asia after 2010 was included in the study. It resulted in the inclusion of 15 countries which were Bangladesh (2011), Congo Republic (2013-2014), Cote d'Ivoire (2011-2012), Ethiopia (2011), Gambia (2013), Mali (2012-2013), Mozambique (2011), Namibia (2013), Nepal (2011), Niger (2012), Nigeria (2013), Pakistan (2012-2013), Sierra Leone (2013), Uganda (2011), and Zambia (2013). The scatter plot diagram was plotted, and the curve was fitted using the WHS-2014. Cox regression and logistic regression were used to estimate adjusted risks (odds ratio) of child mortality and health outcomes using DHSs. The use of non-solid cooking fuel was very high in most of the Sub-Saharan African and South Asian countries. There was a positive correlation between improving access to safe drinking water and sanitation. The exponential curve fitted well with child mortality and household environmental indicators. The use of improved source of water and sanitation significantly related with the lower odds ratio of death, morbidity, and undernutrition among children aged 12-59 months. The risks were

  16. Comparing verbal autopsy cause of death findings as determined by physician coding and probabilistic modelling: a public health analysis of 54 000 deaths in Africa and Asia

    PubMed Central

    Byass, Peter; Herbst, Kobus; Fottrell, Edward; Ali, Mohamed M.; Odhiambo, Frank; Amek, Nyaguara; Hamel, Mary J.; Laserson, Kayla F.; Kahn, Kathleen; Kabudula, Chodziwadziwa; Mee, Paul; Bird, Jon; Jakob, Robert; Sankoh, Osman; Tollman, Stephen M.

    2015-01-01

    Background Coverage of civil registration and vital statistics varies globally, with most deaths in Africa and Asia remaining either unregistered or registered without cause of death. One important constraint has been a lack of fit–for–purpose tools for registering deaths and assigning causes in situations where no doctor is involved. Verbal autopsy (interviewing care–givers and witnesses to deaths and interpreting their information into causes of death) is the only available solution. Automated interpretation of verbal autopsy data into cause of death information is essential for rapid, consistent and affordable processing. Methods Verbal autopsy archives covering 54 182 deaths from five African and Asian countries were sourced on the basis of their geographical, epidemiological and methodological diversity, with existing physician–coded causes of death attributed. These data were unified into the WHO 2012 verbal autopsy standard format, and processed using the InterVA–4 model. Cause–specific mortality fractions from InterVA–4 and physician codes were calculated for each of 60 WHO 2012 cause categories, by age group, sex and source. Results from the two approaches were assessed for concordance and ratios of fractions by cause category. As an alternative metric, the Wilcoxon matched–pairs signed ranks test with two one–sided tests for stochastic equivalence was used. Findings The overall concordance correlation coefficient between InterVA–4 and physician codes was 0.83 (95% CI 0.75 to 0.91) and this increased to 0.97 (95% CI 0.96 to 0.99) when HIV/AIDS and pulmonary TB deaths were combined into a single category. Over half (53%) of the cause category ratios between InterVA–4 and physician codes by source were not significantly different from unity at the 99% level, increasing to 62% by age group. Wilcoxon tests for stochastic equivalence also demonstrated equivalence. Conclusions These findings show strong concordance between InterVA–4 and

  17. Transitioning toward Sustainable Development Goals: The Role of Household Environment in Influencing Child Health in Sub-Saharan Africa and South Asia Using Recent Demographic Health Surveys

    PubMed Central

    Anand, Ankit; Roy, Nobhojit

    2016-01-01

    The Millennium Development Goals are now replaced by 17 sustainable development goals. The emphasis of old goals was on improving water, sanitation, and child mortality conditions in developing countries. The study explored the major question about the association between different household environment conditions with child survival and health in Sub-Saharan African and South Asian countries in the current scenario. This paper estimated the risk of death, morbidity, and undernutrition among children living in households with the improved sources of water, sanitation, and non-solid cooking fuel. Two sources of information are explored in this study. First, data from World Health Statistics (WHS)-2014 for all of the Sub-Saharan African and South Asian countries were used. Second, available standard Demographic and Health Survey (DHS) performed in the countries of Sub-Saharan Africa and South Asia after 2010 was included in the study. It resulted in the inclusion of 15 countries which were Bangladesh (2011), Congo Republic (2013–2014), Cote d’Ivoire (2011–2012), Ethiopia (2011), Gambia (2013), Mali (2012–2013), Mozambique (2011), Namibia (2013), Nepal (2011), Niger (2012), Nigeria (2013), Pakistan (2012–2013), Sierra Leone (2013), Uganda (2011), and Zambia (2013). The scatter plot diagram was plotted, and the curve was fitted using the WHS-2014. Cox regression and logistic regression were used to estimate adjusted risks (odds ratio) of child mortality and health outcomes using DHSs. The use of non-solid cooking fuel was very high in most of the Sub-Saharan African and South Asian countries. There was a positive correlation between improving access to safe drinking water and sanitation. The exponential curve fitted well with child mortality and household environmental indicators. The use of improved source of water and sanitation significantly related with the lower odds ratio of death, morbidity, and undernutrition among children aged 12–59 months. The

  18. Universal Definition of Loss to Follow-Up in HIV Treatment Programs: A Statistical Analysis of 111 Facilities in Africa, Asia, and Latin America

    PubMed Central

    Chi, Benjamin H.; Yiannoutsos, Constantin T.; Westfall, Andrew O.; Newman, Jamie E.; Zhou, Jialun; Cesar, Carina; Brinkhof, Martin W. G.; Mwango, Albert; Balestre, Eric; Carriquiry, Gabriela; Sirisanthana, Thira; Mukumbi, Henri; Martin, Jeffrey N.; Grimsrud, Anna; Bacon, Melanie; Thiebaut, Rodolphe

    2011-01-01

    Background Although patient attrition is recognized as a threat to the long-term success of antiretroviral therapy programs worldwide, there is no universal definition for classifying patients as lost to follow-up (LTFU). We analyzed data from health facilities across Africa, Asia, and Latin America to empirically determine a standard LTFU definition. Methods and Findings At a set “status classification” date, patients were categorized as either “active” or “LTFU” according to different intervals from time of last clinic encounter. For each threshold, we looked forward 365 d to assess the performance and accuracy of this initial classification. The best-performing definition for LTFU had the lowest proportion of patients misclassified as active or LTFU. Observational data from 111 health facilities—representing 180,718 patients from 19 countries—were included in this study. In the primary analysis, for which data from all facilities were pooled, an interval of 180 d (95% confidence interval [CI]: 173–181 d) since last patient encounter resulted in the fewest misclassifications (7.7%, 95% CI: 7.6%–7.8%). A secondary analysis that gave equal weight to cohorts and to regions generated a similar result (175 d); however, an alternate approach that used inverse weighting for cohorts based on variance and equal weighting for regions produced a slightly lower summary measure (150 d). When examined at the facility level, the best-performing definition varied from 58 to 383 d (mean = 150 d), but when a standard definition of 180 d was applied to each facility, only slight increases in misclassification (mean = 1.2%, 95% CI: 1.0%–1.5%) were observed. Using this definition, the proportion of patients classified as LTFU by facility ranged from 3.1% to 45.1% (mean = 19.9%, 95% CI: 19.1%–21.7%). Conclusions Based on this evaluation, we recommend the adoption of ≥180 d since the last clinic visit as a standard LTFU definition. Such

  19. Europa Small Lander Design Concepts

    NASA Astrophysics Data System (ADS)

    Zimmerman, W. F.

    2005-12-01

    Title: Europa Small Lander Design Concepts Authors: Wayne F. Zimmerman, James Shirley, Robert Carlson, Tom Rivellini, Mike Evans One of the primary goals of NASA's Outer Planets Program is to revisit the Jovian system. A new Europa Geophysical Explorer (EGE) Mission has been proposed and is under evaluation. There is in addition strong community interest in a surface science mission to Europa. A Europa Lander might be delivered to the Jovian system with the EGE orbiter. A Europa Astrobiology Lander (EAL) Mission has also been proposed; this would launch sometime after 2020. The primary science objectives for either of these would most likely include: Surface imaging (both microscopic and near-field), characterization of surface mechanical properties (temperature, hardness), assessment of surface and near-surface organic and inorganic chemistry (volatiles, mineralogy, and compounds), characterization of the radiation environment (total dose and particles), characterization of the planetary seismicity, and the measurement of Europa's magnetic field. The biggest challenges associated with getting to the surface and surviving to perform science investigations revolve around the difficulty of landing on an airless body, the ubiquitous extreme topography, the harsh radiation environment, and the extreme cold. This presentation reviews some the recent design work on drop-off probes, also called "hard landers". Hard lander designs have been developed for a range of science payload delivery systems spanning small impactors to multiple science pods tethered to a central hub. In addition to developing designs for these various payload delivery systems, significant work has been done in weighing the relative merits of standard power systems (i.e., batteries) against radioisotope power systems. A summary of the power option accommodation benefits and issues will be presented. This work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under a

  20. The Ultraviolet Spectrograph on the Europa Mission (Europa-UVS)

    NASA Astrophysics Data System (ADS)

    Retherford, K. D.; Gladstone, R.; Greathouse, T. K.; Steffl, A.; Davis, M. W.; Feldman, P. D.; McGrath, M. A.; Roth, L.; Saur, J.; Spencer, J. R.; Stern, S. A.; Pope, S.; Freeman, M. A.; Persyn, S. C.; Araujo, M. F.; Cortinas, S. C.; Monreal, R. M.; Persson, K. B.; Trantham, B. J.; Versteeg, M. H.; Walther, B. C.

    2015-12-01

    NASA's Europa multi-flyby mission is designed to provide a diversity of measurements suited to enrich our understanding of the potential habitability of this intriguing ocean world. The Europa mission's Ultraviolet Spectrograph, Europa-UVS, is the sixth in a series of successful ultraviolet imaging spectrographs (Rosetta-Alice, New Horizons Pluto-Alice, LRO-LAMP) and, like JUICE-UVS (now under Phase B development), is largely based on the most recent of these to fly, Juno-UVS. Europa-UVS observes photons in the 55-210 nm wavelength range, at moderate spectral and spatial resolution along a 7.5° slit. Three distinct apertures send light to the off-axis telescope mirror feeding the long-slit spectrograph: i) a main entrance airglow port is used for most observations (e.g., airglow, aurora, surface mapping, and stellar occultations); ii) a high-spatial-resolution port consists of a small hole in an additional aperture door, and is used for detailed observations of bright targets; and iii) a separate solar port allows for solar occultations, viewing at a 60° offset from the nominal payload boresight. Photon event time-tagging (pixel list mode) and programmable spectral imaging (histogram mode) allow for observational flexibility and optimal science data management. As on Juno-UVS, the effects of penetrating electron radiation on electronic parts and data quality are mitigated through contiguous shielding, filtering of pulse height amplitudes, management of high-voltage settings, and careful use of radiation-hard parts. The science goals of Europa-UVS are to: 1) Determine the composition & chemistry, source & sinks, and structure & variability of Europa's atmosphere, from equator to pole; 2) Search for and characterize active plumes in terms of global distribution, structure, composition, and variability; 3) Explore the surface composition & microphysics and their relation to endogenic & exogenic processes; and 4) Investigate how energy and mass flow in the Europa

  1. Galileo Science Update Europa Unveiled

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A five person panel discuss newly imaged photographs of the surface of Jupiter's satellite Europa. In the discussion the topics that are covered are: surface features, ice and water formation, erosion, volcanism, thermal dissipation, crustal spreading, plate tectonics, impact sites, exobiology, and life.The run time on this video is 49:48 the air date is 1/17/97.

  2. The Europa Clipper mission concept

    NASA Astrophysics Data System (ADS)

    Pappalardo, Robert; Lopes, Rosaly

    Jupiter's moon Europa may be a habitable world. Galileo spacecraft data suggest that an ocean most likely exists beneath Europa’s icy surface and that the “ingredients” necessary for life (liquid water, chemistry, and energy) could be present within this ocean today. Because of the potential for revolutionizing our understanding of life in the solar system, future exploration of Europa has been deemed an extremely high priority for planetary science. A NASA-appointed Science Definition Team (SDT), working closely with a technical team from the Jet Propulsion Laboratory (JPL) and the Applied Physics Laboratory (APL), recently considered options for a future strategic mission to Europa, with the stated science goal: Explore Europa to investigate its habitability. The group considered several mission options, which were fully technically developed, then costed and reviewed by technical review boards and planetary science community groups. There was strong convergence on a favored architecture consisting of a spacecraft in Jupiter orbit making many close flybys of Europa, concentrating on remote sensing to explore the moon. Innovative mission design would use gravitational perturbations of the spacecraft trajectory to permit flybys at a wide variety of latitudes and longitudes, enabling globally distributed regional coverage of the moon’s surface, with nominally 45 close flybys at altitudes from 25 to 100 km. We will present the science and reconnaissance goals and objectives, a mission design overview, and the notional spacecraft for this concept, which has become known as the Europa Clipper. The Europa Clipper concept provides a cost-efficient means to explore Europa and investigate its habitability, through understanding the satellite’s ice and ocean, composition, and geology. The set of investigations derived from these science objectives traces to a notional payload for science, consisting of: Ice Penetrating Radar (for sounding of ice-water interfaces

  3. A Pragmatic Path to Investigating Europa's Habitability

    NASA Astrophysics Data System (ADS)

    Pappalardo, R. T.; Bagenal, F.; Barr, A. C.; Bills, B. G.; Blaney, D. L.; Blankenship, D. D.; Connerney, J. E.; Kurth, W. S.; McGrath, M. A.; Moore, J. M.; Prockter, L. M.; Senske, D. A.; Smith, D. E.; Garner, G. J.; Magner, T. J.; Cooke, B. C.; Mallder, V.; Crum, R.

    2011-12-01

    Assessment of Europa's habitability will progress via a comprehensive investigation of Europa's subsurface ocean, chemical composition, and internal dynamical processes. The National Research Council's Planetary Decadal Survey placed an extremely high priority on Europa science but noted that the budget profile for the Jupiter Europa Orbiter (JEO) mission concept is incompatible with NASA's projected planetary science budget. Thus, NASA enlisted a small Europa Science Definition Team (ESDT) to consider more pragmatic Europa mission options. In its preliminary findings, the ESDT embraces a science scope and instrument complement comparable to the science "floor" for JEO, but with a radically different mission implementation. The ESDT is studying a two-element mission architecture, in which two relatively low-cost spacecraft would fulfill the Europa science objectives. An envisioned Europa orbital element would carry only a very small geophysics payload, addressing those investigations that are best carried out from Europa orbit. An envisioned separate multiple Europa flyby element (in orbit about Jupiter) would emphasize remote sensing. This mission architecture would provide for a subset of radiation-shielded instruments (all relatively low mass, power, and data rate) to be delivered into Europa orbit by a modest spacecraft, saving on propellant and other spacecraft resources. More resource-intensive remote sensing instruments would achieve their science objectives through a conservative multiple-flyby approach, which is better suited to handle larger masses and higher data volumes. Separation of the payload into two spacecraft elements, phased in time, would permit costs to be spread more uniformly over multiple years, avoiding an excessively high peak in the funding profile. Implementation of each spacecraft would be greatly simplified compared to previous Europa mission concepts, minimizing new development while achieving the key Europa science objectives. We

  4. A Pragmatic Path to Investigating Europa's Habitability

    NASA Astrophysics Data System (ADS)

    Pappalardo, R. T.; Bagenal, F.; Barr, A. C.; Bills, B. G.; Blaney, D. L.; Blankenship, D. D.; Connerney, J. E. P.; Kurth, W.; McGrath, M.; Moore, J. M.; Prockter, L. M.; Senske, D. A.; Smith, D. E.; Garner, G. J.; Magner, T.; Hibbard, K. E.; Cooke, B. C.

    2011-10-01

    Assessment of Europa's habitability, as an overarching science goal, will progress via a comprehensive investigation of Europa's subsurface ocean, chemical composition, and internal dynamical processes. The National Research Council's Planetary Decadal Survey placed an extremely high priority on Europa science but noted that the budget profile for the Jupiter Europa Orbiter (JEO) mission concept is incompatible with NASA's projected planetary science budget. Thus, NASA enlisted a small Europa Science Definition Team (ESDT) to consider more pragmatic Europa mission options. In its preliminary findings (May, 2011), the ESDT embraces a science scope and instrument complement comparable to the science "floor" for JEO, but with a radically different mission implementation. The ESDT is studying a twoelement mission architecture, in which two relatively low-cost spacecraft would fulfill the Europa science objectives. An envisioned Europa orbital element would carry only a very small geophysics payload, addressing those investigations that are best carried out from Europa orbit. An envisioned separate multiple Europa flyby element (in orbit about Jupiter) would emphasize remote sensing. This mission architecture would provide for a subset of radiationshielded instruments (all relatively low mass, power, and data rate) to be delivered into Europa orbit by a modest spacecraft, saving on propellant and other spacecraft resources. More resource-intensive remote sensing instruments would achieve their science objectives through a conservative multipleflyby approach, which is better suited to handle larger masses and higher data volumes, and which aims to limit radiation exposure. Separation of the payload into two spacecraft elements, phased in time, would permit costs to be spread more uniformly over multiple years, avoiding an excessively high peak in the funding profile. Implementation of each spacecraft would be greatly simplified compared to previous Europa mission

  5. Galileo NIMS Observations of Europa

    NASA Astrophysics Data System (ADS)

    Shirley, J. H.; Ocampo, A. C.; Carlson, R. W.

    2000-10-01

    The Galileo spacecraft began its tour of the Jovian system in December, 1995. The Galileo Millenium Mission (GMM) is scheduled to end in January, 2003. The opportunities to observe Europa in the remaining orbits are severely limited. Thus the catalog of NIMS observations of Europa is virtually complete. We summarize and describe this extraordinary dataset, which consists of 77 observations. The observations may be grouped in three categories, based on the scale of the data (km/pixel). The highest-resolution observations, with projected scales of 1-9 km/pixel, comprise one important subset of the catalog. These 29 observations sample both leading and trailing hemispheres at low and high latitudes. They have been employed in studies exploring the chemical composition of the non-ice surface materials on Europa (McCord et al., 1999, JGR 104, 11,827; Carlson et al., 1999, Science 286, 97). A second category consists of regional observations at moderate resolution. These 15 observations image Europa's surface at scales of 15-50 km/pixel, appropriate for construction of regional and global mosaics. A gap in coverage for longitudes 270-359 W may be partially filled during the 34th orbit of GMM. The final category consists of 33 global observations with scales ranging upward from 150 km/pixel. The noise levels are typically much reduced in comparison to observations taken deep within Jupiter's magnetosphere. Distant observations obtained during the 11th orbit revealed the presence of hydrogen peroxide on Europa's surface (Carlson et al., 1999b, Science 283, 2062). NIMS observations are archived in ISIS-format "cubes," which are available to researchers through the Planetary Data System (http://www-pdsimage.jpl.nasa.gov/PDS/Public/Atlas/Atlas.html). Detailed guides to every NIMS observation may be downloaded from the NIMS web site (http://jumpy.igpp.ucla.edu/ nims/).

  6. Europa Explorer Operational Scenarios Development

    NASA Technical Reports Server (NTRS)

    Lock, Robert E.; Pappalardo, Robert T.; Clark, Karla B.

    2008-01-01

    In 2007, NASA conducted four advanced mission concept studies for outer planets targets: Europa, Ganymede, Titan and Enceladus. The studies were conducted in close cooperation with the planetary science community. Of the four, the Europa Explorer Concept Study focused on refining mission options, science trades and implementation details for a potential flagship mission to Europa in the 2015 timeframe. A science definition team (SDT) was appointed by NASA to guide the study. A JPL-led engineering team worked closely with the science team to address 3 major focus areas: 1) credible cost estimates, 2) rationale and logical discussion of radiation risk and mitigation approaches, and 3) better definition and exploration of science operational scenario trade space. This paper will address the methods and results of the collaborative process used to develop Europa Explorer operations scenarios. Working in concert with the SDT, and in parallel with the SDT's development of a science value matrix, key mission capabilities and constraints were challenged by the science and engineering members of the team. Science goals were advanced and options were considered for observation scenarios. Data collection and return strategies were tested via simulation, and mission performance was estimated and balanced with flight and ground system resources and science priorities. The key to this successful collaboration was a concurrent development environment in which all stakeholders could rapidly assess the feasibility of strategies for their success in the full system context. Issues of science and instrument compatibility, system constraints, and mission opportunities were treated analytically and objectively leading to complementary strategies for observation and data return. Current plans are that this approach, as part of the system engineering process, will continue as the Europa Explorer Concept Study moves toward becoming a development project.

  7. Simulation of Europa's water plume .

    NASA Astrophysics Data System (ADS)

    Lucchetti, A.; Cremonese, G.; Schneider, N. M.; Plainaki, C.; Mazzotta Epifani, E.; Zusi, M.; Palumbo, P.

    Plumes on Europa would be extremely interesting science and mission targets, particularly due to the unique opportunity to obtain direct information on the subsurface composition, thereby addressing Europa's potential habitability. The existence of water plume on the Jupiter's moon Europa has been long speculated until the recent discover. HST imaged surpluses of hydrogen Lyman alpha and oxygen emissions above the southern hemisphere in December 2012 that are consistent with two 200 km high plumes of water vapor (Roth et al. 2013). In previous works ballistic cryovolcanism has been considered and modeled as a possible mechanism for the formation of low-albedo features on Europa's surface (Fagents et al. 2000). Our simulation agrees with the model of Fagents et al. (2000) and consists of icy particles that follow ballistic trajectories. The goal of such an analysis is to define the height, the distribution and the extension of the icy particles falling on the moon's surface as well as the thickness of the deposited layer. We expect to observe high albedo regions in contrast with the background albedo of Europa surface since we consider that material falling after a cryovolcanic plume consists of snow. In order to understand if this phenomenon is detectable we convert the particles deposit in a pixel image of albedo data. We consider also the limb view of the plume because, even if this detection requires optimal viewing geometry, it is easier detectable in principle against sky. Furthermore, we are studying the loss rates due to impact electron dissociation and ionization to understand how these reactions decrease the intensity of the phenomenon. We expect to obtain constraints on imaging requirements necessary to detect potential plumes that could be useful for ESA's JUICE mission, and in particular for the JANUS camera (Palumbo et al. 2014).

  8. An Overview of the Jupiter Europa Orbiter Concept's Europa Science Phase Orbit Design

    NASA Technical Reports Server (NTRS)

    Lock, Robert E.; Ludwinski, Jan M.; Petropoulos, Anastassios E.; Clark, Karla B.; Pappalardo, Robert T.

    2009-01-01

    Jupiter Europa Orbiter (JEO), the proposed NASA element of the proposed joint NASA-ESA Europa Jupiter System Mission (EJSM), could launch in February 2020 and conceivably arrive at Jupiter in December of 2025. The concept is to perform a multi-year study of Europa and the Jupiter system, including 30 months of Jupiter system science and a comprehensive Europa orbit phase of 9 months. This paper provides an overview of the JEO concept and describes the Europa Science phase orbit design and the related science priorities, model pay-load and operations scenarios needed to conduct the Europa Science phase. This overview is for planning and discussion purposes only.

  9. Exobiological Exploration of Europa (E3) Europa Lander

    NASA Technical Reports Server (NTRS)

    Stillwagen, F. H.; Manvi, Ramachandra; Seywald, Hans; Park, Sang-Young; Kolacinski, Rick

    2002-01-01

    The search for life outside Earth's protected atmosphere is a compelling testament to the quest by mankind to determine if "we" are alone in the universe. The phenomenal success of the NASA Galileo spacecraft has indicated that the moons of Jupiter, and most notably Europa, may indeed contain subsurface liquid under an icy surface. This speculation of a salty liquid subsurface fuels expert opinions that biological products may exist. The Revolutionary Aerospace Systems Concepts (RASC) effort at Langley Research Center, initiated by NASA Headquarters, pushes NASA and the Aerospace/Science community to target advanced evolutionary technology usage to provide a Europa Lander concept targeted for completion within the next 50 years. The study effort indicates the use of certain advanced technologies to achieve a subsurface penetrator and liquid explorer in the approximately 2040 timeframe.

  10. The Europa Jupiter System Mission

    NASA Astrophysics Data System (ADS)

    Hendrix, A. R.; Clark, K.; Erd, C.; Pappalardo, R.; Greeley, R. R.; Blanc, M.; Lebreton, J.; van Houten, T.

    2009-05-01

    Europa Jupiter System Mission (EJSM) will be an international mission that will achieve Decadal Survey and Cosmic Vision goals. NASA and ESA have concluded a joint study of a mission to Europa, Ganymede and the Jupiter system with orbiters developed by NASA and ESA; contributions by JAXA are also possible. The baseline EJSM architecture consists of two primary elements operating in the Jovian system: the NASA-led Jupiter Europa Orbiter (JEO), and the ESA-led Jupiter Ganymede Orbiter (JGO). The JEO mission has been selected by NASA as the next Flagship mission to the out solar system. JEO and JGO would execute an intricately choreographed exploration of the Jupiter System before settling into orbit around Europa and Ganymede, respectively. JEO and JGO would carry eleven and ten complementary instruments, respectively, to monitor dynamic phenomena (such as Io's volcanoes and Jupiter's atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and characterize water oceans beneath the ice shells of Europa and Ganymede. EJSM will fully addresses high priority science objectives identified by the National Research Council's (NRC's) Decadal Survey and ESA's Cosmic Vision for exploration of the outer solar system. The Decadal Survey recommended a Europa Orbiter as the highest priority outer planet flagship mission and also identified Ganymede as a highly desirable mission target. EJSM would uniquely address several of the central themes of ESA's Cosmic Vision Programme, through its in-depth exploration of the Jupiter system and its evolution from origin to habitability. EJSM will investigate the potential habitability of the active ocean-bearing moons Europa and Ganymede, detailing the geophysical, compositional, geological and external processes that affect these icy worlds. EJSM would also explore Io and Callisto, Jupiter's atmosphere, and the Jovian magnetosphere. By understanding the Jupiter system and unraveling its history, the

  11. The Europa Jupiter system mission

    NASA Astrophysics Data System (ADS)

    Clark, K.; Stankov, A.; Pappalardo, R. T.; Greeley, R.; Blanc, M.; Lebreton, J.-P.; van Houten, T.

    2009-04-01

    Europa Jupiter System Mission (EJSM)— would be an international mission that would achieve Decadal Survey and Cosmic Vision goals. NASA and ESA have concluded a joint study of a mission to Europa, Ganymede and the Jupiter system with orbiters developed by NASA and ESA; contributions by JAXA are also possible. The baseline EJSM architecture consists of two primary elements operating in the Jovian system: the NASA-led Jupiter Europa Orbiter (JEO), and the ESA-led Jupiter Ganymede Orbiter (JGO). JEO and JGO would execute an intricately choreographed exploration of the Jupiter System be-fore settling into orbit around Europa and Ganymede, respectively. JEO and JGO would carry eleven and ten complementary instruments, respectively, to monitor dynamic phenomena (such as Io's volcanoes and Jupi-ter's atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and charac-terize water oceans beneath the ice shells of Europa and Ganymede. EJSM would fully addresses high priority science objectives identified by the National Research Coun-cil's (NRC's) Decadal Survey and ESA's Cosmic Vi-sion for exploration of the outer solar system. The De-cadal Survey recommended a Europa Orbiter as the highest priority outer planet flagship mission and also identified Ganymede as a highly desirable mission tar-get. EJSM would uniquely addresse several of the cen-tral themes of ESA's Cosmic Vision Programme, through its in-depth exploration of the Jupiter system and its evolution from origin to habitability. EJSM would investigate the potential habitability of the active ocean-bearing moons Europa and Gany-mede, detailing the geophysical, compositional, geo-logical, and external processes that affect these icy worlds. EJSM would also explore Io and Callisto, Jupi-ter's atmosphere, and the Jovian magnetosphere. By understanding the Jupiter system and unraveling its history, the formation and evolution of gas giant plan-ets and their satellites would be

  12. Geophysical controls of chemical disequilibria in Europa

    NASA Astrophysics Data System (ADS)

    Vance, S. D.; Hand, K. P.; Pappalardo, R. T.

    2016-05-01

    The ocean in Jupiter's moon Europa may have redox balance similar to Earth's. On Earth, low-temperature hydration of crustal olivine produces substantial hydrogen, comparable to any potential flux from volcanic activity. Here we compare hydrogen and oxygen production rates of the Earth system with fluxes to Europa's ocean. Even without volcanic hydrothermal activity, water-rock alteration in Europa causes hydrogen fluxes 10 times smaller than Earth's. Europa's ocean may have become reducing for a brief epoch, for example, after a thermal-orbital resonance ˜2 Gyr after accretion. Estimated oxidant flux to Europa's ocean is comparable to estimated hydrogen fluxes. Europa's ice delivers oxidants to its ocean at the upper end of these estimates if its ice is geologically active, as evidence of geologic activity and subduction implies.

  13. A SEARCH FOR MAGNESIUM IN EUROPA'S ATMOSPHERE

    SciTech Connect

    Hoerst, S. M.; Brown, M. E.

    2013-02-20

    Europa's tenuous atmosphere results from sputtering of the surface. The trace element composition of its atmosphere is therefore related to the composition of Europa's surface. Magnesium salts are often invoked to explain Galileo Near Infrared Mapping Spectrometer spectra of Europa's surface, thus magnesium may be present in Europa's atmosphere. We have searched for magnesium emission in the Hubble Space Telescope Faint Object Spectrograph archival spectra of Europa's atmosphere. Magnesium was not detected and we calculate an upper limit on the magnesium column abundance. This upper limit indicates that either Europa's surface is depleted in magnesium relative to sodium and potassium, or magnesium is not sputtered as efficiently resulting in a relative depletion in its atmosphere.

  14. Mosaic of Europa's Ridges, Craters

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This view of the icy surface of Jupiter's moon, Europa, is a mosaic of two pictures taken by the Solid State Imaging system on board the Galileo spacecraft during a close flyby of Europa on February 20, 1997. The pictures were taken from a distance of 2,000 kilometers (1,240 miles). The area shown is about 14 kilometers by 17 kilometers (8.7 miles by 10.6 miles), and has a resolution of 20 meters (22 yards) per pixel. Illumination is from the right (east). The picture is centered at about 14.8 north latitude, 273.8 west longitude, in Europa's trailing hemisphere.

    One of the youngest features seen in this area is the double ridge cutting across the picture from the lower left to the upper right. This double ridge is about 2.6 kilometers (1.6 miles) wide and stands some 300 meters (330 yards) high. Small craters are most easily seen in the smooth deposits along the south margin of the prominent double ridge, and in the rugged ridged terrain farther south. The complexly ridged terrain seen here shows that parts of the icy crust of Europa have been modified by intense faulting and disruption, driven by energy from the planet's interior.

    The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington D.C. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at: http://galileo.jpl.nasa.gov.

  15. Europa Imaging Highlights during GEM

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During the two year Galileo Europa Mission (GEM), NASA's Galileo spacecraft will focus intensively on Jupiter's intriguing moon, Europa. This montage shows samples of some of the features that will be imaged during eight successive orbits. The images in this montage are in order of increasing orbit from the upper left (orbit 11) to the lower right (orbit 19).

    DESCRIPTIONS AND APPROXIMATE RESOLUTIONSTriple bands and dark spots

    1.6 kilometers/pixelConamara Chaos

    1.6 kilometers/pixelMannan'an Crater

    1.6 kilometers/ pixelCilix

    1.6 kilometers/pixelAgenor Linea and Thrace Macula

    2 kilometers/pixelSouth polar terrain

    2 kilometers/pixelRhadamanthys Linea

    1.6 kilometers/pixelEuropa plume search

    7 kilometers/pixel

    1. Triple bands and dark spots were the focus of some images from Galileo's eleventh orbit of Jupiter. Triple bands are multiple ridges with dark deposits along the outer margins. Some extend for thousands of kilometers across Europa's icy surface. They are cracks in the ice sheet and indicate the great stresses imposed on Europa by tides raised by Jupiter, as well as Europa's neighboring moons, Ganymede and Io. The dark spots or 'lenticulae' are spots of localized disruption.

    2. The Conamara Chaos region reveals icy plates which have broken up, moved, and rafted into new positions. This terrain suggests that liquid water or ductile ice was present near the surface. On Galileo's twelfth orbit of Jupiter, sections of this region with resolutions as high as 10 meters per picture element will be obtained.

    3. Mannann'an Crater is a feature newly discovered by Galileo in June 1996. Color and high resolution images (to 40 meters per picture element) from Galileo's fourteenth orbit of Jupiter will offer a close look at the crater and help characterize how impacts affect the icy surface of this moon.

    4. Cilix, a large mound about 1.5 kilometers high, is the center of Europa's coordinate system. Its concave top and what may be flow

  16. Europa Imaging Highlights during GEM

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During the two year Galileo Europa Mission (GEM), NASA's Galileo spacecraft will focus intensively on Jupiter's intriguing moon, Europa. This montage shows samples of some of the features that will be imaged during eight successive orbits. The images in this montage are in order of increasing orbit from the upper left (orbit 11) to the lower right (orbit 19).

    DESCRIPTIONS AND APPROXIMATE RESOLUTIONSTriple bands and dark spots

    1.6 kilometers/pixelConamara Chaos

    1.6 kilometers/pixelMannan'an Crater

    1.6 kilometers/ pixelCilix

    1.6 kilometers/pixelAgenor Linea and Thrace Macula

    2 kilometers/pixelSouth polar terrain

    2 kilometers/pixelRhadamanthys Linea

    1.6 kilometers/pixelEuropa plume search

    7 kilometers/pixel

    1. Triple bands and dark spots were the focus of some images from Galileo's eleventh orbit of Jupiter. Triple bands are multiple ridges with dark deposits along the outer margins. Some extend for thousands of kilometers across Europa's icy surface. They are cracks in the ice sheet and indicate the great stresses imposed on Europa by tides raised by Jupiter, as well as Europa's neighboring moons, Ganymede and Io. The dark spots or 'lenticulae' are spots of localized disruption.

    2. The Conamara Chaos region reveals icy plates which have broken up, moved, and rafted into new positions. This terrain suggests that liquid water or ductile ice was present near the surface. On Galileo's twelfth orbit of Jupiter, sections of this region with resolutions as high as 10 meters per picture element will be obtained.

    3. Mannann'an Crater is a feature newly discovered by Galileo in June 1996. Color and high resolution images (to 40 meters per picture element) from Galileo's fourteenth orbit of Jupiter will offer a close look at the crater and help characterize how impacts affect the icy surface of this moon.

    4. Cilix, a large mound about 1.5 kilometers high, is the center of Europa's coordinate system. Its concave top and what may be flow

  17. Global Geologic Map of Europa

    NASA Technical Reports Server (NTRS)

    Doggett, T.; Figueredo, P.; Greeley, R.; Hare, T.; Kolb, E.; Mullins, K.; Senske, D.; Tanaka, K.; Weiser, S.

    2008-01-01

    Europa, with its indications of a sub-ice ocean, is of keen interest to astrobiology and planetary geology. Knowledge of the global distribution and timing of Europan geologic units is a key step for the synthesis of data from the Galileo mission, and for the planning of future missions to the satellite. The first geologic map of Europa was produced at a hemisphere scale with low resolution Voyager data. Following the acquisition of higher resolution data by the Galileo mission, researchers have identified surface units and determined sequences of events in relatively small areas of Europa through geologic mapping using images at various resolutions acquired by Galileo's Solid State Imaging camera. These works provided a local to subregional perspective and employed different criteria for the determination and naming of units. Unified guidelines for the identification, mapping and naming of Europan geologic units were put forth by and employed in regional-to-hemispheric scale mapping which is now being expanded into a global geologic map. A global photomosaic of Galileo and Voyager data was used as a basemap for mapping in ArcGIS, following suggested methodology of all-stratigraphy for planetary mapping. The following units have been defined in global mapping and are listed in stratigraphic order from oldest to youngest: ridged plains material, Argadnel Regio unit, dark plains material, lineaments, disrupted plains material, lenticulated plains material and Chaos material.

  18. Science potential from a Europa lander.

    PubMed

    Pappalardo, R T; Vance, S; Bagenal, F; Bills, B G; Blaney, D L; Blankenship, D D; Brinckerhoff, W B; Connerney, J E P; Hand, K P; Hoehler, T M; Leisner, J S; Kurth, W S; McGrath, M A; Mellon, M T; Moore, J M; Patterson, G W; Prockter, L M; Senske, D A; Schmidt, B E; Shock, E L; Smith, D E; Soderlund, K M

    2013-08-01

    The prospect of a future soft landing on the surface of Europa is enticing, as it would create science opportunities that could not be achieved through flyby or orbital remote sensing, with direct relevance to Europa's potential habitability. Here, we summarize the science of a Europa lander concept, as developed by our NASA-commissioned Science Definition Team. The science concept concentrates on observations that can best be achieved by in situ examination of Europa from its surface. We discuss the suggested science objectives and investigations for a Europa lander mission, along with a model planning payload of instruments that could address these objectives. The highest priority is active sampling of Europa's non-ice material from at least two different depths (0.5-2 cm and 5-10 cm) to understand its detailed composition and chemistry and the specific nature of salts, any organic materials, and other contaminants. A secondary focus is geophysical prospecting of Europa, through seismology and magnetometry, to probe the satellite's ice shell and ocean. Finally, the surface geology can be characterized in situ at a human scale. A Europa lander could take advantage of the complex radiation environment of the satellite, landing where modeling suggests that radiation is about an order of magnitude less intense than in other regions. However, to choose a landing site that is safe and would yield the maximum science return, thorough reconnaissance of Europa would be required prior to selecting a scientifically optimized landing site. PMID:23924246

  19. Io and Europa Meet Again

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This beautiful image of the crescents of volcanic Io and more sedate Europa is a combination of two New Horizons images taken March 2, 2007, about two days after New Horizons made its closest approach to Jupiter. A lower-resolution color image snapped by the Multispectral Visual Imaging Camera (MVIC) at 10:34 universal time (UT) has been merged with a higher-resolution black-and-white image taken by the Long Range Reconnaissance Imager (LORRI) at 10:23 UT. The composite image shows the relative positions of Io and Europa, which were moving past each other during the image sequence, as they were at the time the LORRI image was taken.

    This image was taken from a range of 4.6 million kilometers (2.8 million miles) from Io and 3.8 million kilometers (2.4 million miles) from Europa. Although the moons appear close together in this view, a gulf of 790,000 kilometers (490,000 miles) separates them. Io's night side is lit up by light reflected from Jupiter, which is off the frame to the right. Europa's night side is dark, in contrast to Io, because this side of Europa faces away from Jupiter.

    Here Io steals the show with its beautiful display of volcanic activity. Three volcanic plumes are visible. Most conspicuous is the enormous 300-kilometer (190-mile) high plume from the Tvashtar volcano at the 11 o'clock position on Io's disk. Two much smaller plumes are also visible: that from the volcano Prometheus, at the 9 o'clock position on the edge of Io's disk, and from the volcano Amirani, seen between Prometheus and Tvashtar along Io's terminator (the line dividing day and night). The Tvashtar plume appears blue because of the scattering of light by tiny dust particles ejected by the volcanoes, similar to the blue appearance of smoke. In addition, the contrasting red glow of hot lava can be seen at the source of the Tvashtar plume.

    The images are centered at 1 degree North, 60 degrees West on Io, and 0 degrees North, 149 degrees West on Europa. The color

  20. Search for Trace Species in Europa's Exosphere

    NASA Astrophysics Data System (ADS)

    McGrath, M. A.; Sparks, W. B.; Spencer, J. R.

    2015-12-01

    Understanding the present surface composition of Europa provides critical information about its potential habitability. From Earth we currently have very few tools at our disposal to measure Europa's composition. Two notable exceptions are Keck NIR spectroscopy (cf Brown and Hand 2013) and Hubble Space Telescope UV spectroscopy (cf Cunningham et al. 2015). In March 2015 we obtained 5 orbits of deep UV spectroscopy of Europa using the Cosmic Origins Spectrograph covering wavelength range 1170-1760 Å. The purpose of the observations was to detect trace species in Europa's exosphere, which is generated by charged particle sputtering of Europa's water ice surface. The composition of the exosphere therefore provides an indirect measurement of surface composition. Furthermore, if active plumes are present, the composition of the exosphere may also reflect the composition of Europa's subsurface water reservoir. Of particular interest in the observed wavelength range are multiplets of atomic chlorine, because chlorine is predicted to be a major constituent of Europa's ocean (Kargel et al. 2000), and Na and K chlorides are expected to be major constituents of the icy shell (Zolotov and Shock 2001; Zolotov and Kargel 2009). The present situation at Europa is analogous to that at Io in the late 1990s, when chlorine ions were first detected in the plasma near Io (Kuppers and Schneider 2000), motivating searches for atomic chlorine and chlorine-bearing species that were subsequently detected in Io's atmosphere (Lellouch et al. 2003, Feaga et al. 2004). Galileo plasma measurements have detected chlorine ions near Europa (Volwerk et al. 2001), which has motivated the present search for chlorine in Europa's exosphere. We will present the new COS spectra of Europa and discuss the implications of the trace species that have been detected in these data.

  1. Numerical Study of Orbits around Europa

    NASA Astrophysics Data System (ADS)

    Mourao, Decio; Carvalho, Jean Paulo; Vilhena de Moraes, Rodolpho; Cardoso dos Santos, Josué; Campos de Carvalho Costa, Luis Fernando

    NASA's Galileo spacecraft probe recently discovered what appears to be a body of liquid water locked inside the icy shell of Jupiter’s moon Europa. The improved likelihood of life on Europa motivated new mission proposals. In this work we used numerical simulations to compare several possible orbits of satellites near the surface of Europa. We spread a set of particles around the satellite with different initially conditions, from 50 to 500km altitude and inclinations higher than 35 degrees, and we monitored the evolution of the test particles during the numerical integrations. We consider the effect of the oblateness of Europa by considering the C22,J2 and J4 parameters and Jupiter gravitational perturbation. These perturbations were first accounted for separately in order to better understand the importance of each effect, and then considered jointly. All particles collide with the Europa surface in a few days. The oblateness of Jupiter alone causes particles with high inclination to collide with the surface of Europa, while the oblateness of Europa affects low orbits decreasing the lifetime of most of the particles. We identified a stable region of orbits with initial altitudes around 300 km of altitude and 90 degrees of inclination. Particles in this region survived more than 200 days. In most of the simulations pericenter initial values near 90 or 270 degrees favor a higher lifetime for the particles, even when considering Europa oblateness.

  2. Ancient Impact Basin on Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This feature on Europa was seen as a dark, diffuse circular patch on a previous Galileo global image of Europa's leading hemisphere on April 3, 1997. The 'bulls-eye' pattern appears to be a 140- kilometer (86-mile) wide impact scar (about the size of the island of Hawaii) which formed as the surface fractured minutes after a mountain-sized asteroid or comet slammed into the satellite. This approximately 214-kilometer (132-mile) wide picture is the product of three images which have been processed in false color to enhance shapes and compositions.

    North is toward the top of this picture, which is illuminated from sunlight coming from the west. This color composite reveals a sequence of events which have modified the surface of Europa. The earliest event was the impact which formed the Tyre structure at 34 degrees north latitude and 146.5 degrees west longitude. The impact was followed by the formation of the reddish lines superposed on Tyre. The red color designates areas that are probably a dirty water ice mixture. The fine blue-green lines crossing the region from west to east appear to be ridges which formed after the crater.

    The images were taken on April 4, 1997, at a resolution of 595 meters (1950 feet) per picture element and a range of 29,000 kilometers (17,900 miles). The images were taken by Galileo's solid state imaging (CCD) system.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  3. Highest Resolution Image of Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During its twelfth orbit around Jupiter, on Dec. 16, 1997, NASA's Galileo spacecraft made its closest pass of Jupiter's icy moon Europa, soaring 200 kilometers (124 miles) kilometers above the icy surface. This image was taken near the closest approach point, at a range of 560 kilometers (335 miles) and is the highest resolution picture of Europa that will be obtained by Galileo. The image was taken at a highly oblique angle, providing a vantage point similar to that of someone looking out an airplane window. The features at the bottom of the image are much closer to the viewer than those at the top of the image. Many bright ridges are seen in the picture, with dark material in the low-lying valleys. In the center of the image, the regular ridges and valleys give way to a darker region of jumbled hills, which may be one of the many dark pits observed on the surface of Europa. Smaller dark, circular features seen here are probably impact craters.

    North is to the right of the picture, and the sun illuminates the surface from that direction. This image, centered at approximately 13 degrees south latitude and 235 degrees west longitude, is approximately 1.8 kilometers (1 mile) wide. The resolution is 6 meters (19 feet) per picture element. This image was taken on December 16, 1997 by the solid state imaging system camera on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  4. A Pragmatic Path to Investigating Europa's Habitability

    NASA Technical Reports Server (NTRS)

    Pappalardo; Bengenal; Bar; Bills; Blankenship; Connerney; Kurth; McGrath; Moore; Prockter; Senske; Smith; Garner; Magner; Hibbard; Cooke

    2011-01-01

    Assessment of Europa's habitability, as an overarching science goal, will progress via a comprehensive investigation of Europa's subsurface ocean, chemical composition, and internal dynamical processes, The National Research Council's Planetary Decadal Survey placed an extremely high priority on Europa science but noted that the budget profile for the Jupiter Europa Orbiter (1EO) mission concept is incompatible with NASA's projected planetary science budget Thus, NASA enlisted a small Europa Science Definition Team (ESDT) to consider more pragmatic Europa mission options, In its preliminary findings (May, 2011), the ESDT embraces a science scope and instrument complement comparable to the science "floor" for JEO, but with a radically different mission implementation. The ESDT is studying a two-element mission architecture, in which two relatively low-cost spacecraft would fulfill the Europa science objectives, An envisioned Europa orbital element would carry only a very small geophysics payload, addressing those investigations that are best carried out from Europa orbit An envisioned separate multiple Europa flyby element (in orbit about Jupiter) would emphasize remote sensing, This mission architecture would provide for a subset of radiation-shielded instruments (all relatively low mass, power, and data rate) to be delivered into Europa orbit by a modest spacecraft, saving on propellant and other spacecraft resources, More resource-intensive remote sensing instruments would achieve their science objectives through a conservative multiple-flyby approach, that is better situated to handle larger masses and higher data volumes, and which aims to limit radiation exposure, Separation of the payload into two spacecraft elements, phased in time, would permit costs to be spread more uniformly over mUltiple years, avoiding an excessively high peak in the funding profile, Implementation of each spacecraft would be greatly simplified compared to previous Europa mission

  5. Mapping Imaging Spectrometer for Europa (MISE)

    NASA Astrophysics Data System (ADS)

    Blaney, D. L.; Clark, R. N.; Dalton, J. B.; Davies, A. G.; Green, R. O.; Hedman, M. M.; Hibbits, C. A.; Langevin, Y. J.; Lunine, J. I.; McCord, T. B.; Soderblom, J. M.; Cable, M. L.; Mouroulis, P.; Kim, W.; Dorsky, L. I.; Strohbehn, K.

    2015-10-01

    The Mapping Imaging Spectrometer for Europa(MISE) instrument is designed to be able to unravel the composition of Europa, and to provide new insight into the processes that have in the past and continue to shape Europa, and on the habitability of Europa's ocean. The MISE design is the result of collaboration between NASA's Jet Propulsion Laboratory (California Institute of Technology) and the Applied Physics Laboratory (John Hopkins' University). JPL's Discovery Moon Mineralogy Mapper (M3) on Chandrayan-1 and APL's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) comprise the technical basis for MISE. Internal JPL and APL investments in conjunction with NASA support under the ICEE program has allowed for instrument technology development and testing to achieve a design which would perform in Europa's radiation environment and meet potential sterilization requirements due to planetary protection.

  6. Prominent Doublet Ridges on Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image of Jupiter's satellite Europa was obtained from a range of 7364 miles (11851 km) by the Galileo spacecraft during its fourth orbit around Jupiter and its first close pass of Europa. The image spans 30 miles by 57 miles (48 km x 91 km) and shows features as small as 800 feet (240 meters) across, a resolution more than 150 times better than the best Voyager coverage of this area. The sun illuminates the scene from the right. The large circular feature in the upper left of the image could be the scar of a large meteorite impact. Clusters of small craters seen in the right of the image may mark sites where debris thrown from this impact fell back to the surface. Prominent doublet ridges over a mile (1.6 km) wide cross the plains in the right part of the image; younger ridges overlap older ones, allowing the sequence of formation to be determined. Gaps in ridges indicate areas where emplacement of new surface material has obliterated pre-existing terrain.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  7. Mapping Elliptical Orbits Around Europa

    NASA Astrophysics Data System (ADS)

    Vilhena de Moraes, Rodolpho; Prado, Antonio; Carvalho, Jean Paulo; Cardoso dos Santos, Josué

    Due to specifics scientific purposes space missions has been proposed to explore natural satellites, comets and asteroids sending artificial satellites orbiting around these bodies. The planning of such missions must be taken into account a good choice for the orbits that reduces the cost related to station-keeping and the increasing the duration of the mission. The present research has the objective of using a new concept to map with respect the station-keeping maneuvers to study elliptical orbits around Europa. This concept is based in the integral of the perturbing forces over the time. This value can estimate the total variation of velocity received by the spacecraft from the perturbations forces acting on it. The value of this integral is a characteristic of the perturbations considered and the orbit chosen for the spacecraft. Numerical simulations are made showing the value of this integral for orbits around Europa as a function of the eccentricity and semi-major axis of the orbits. An important application of the present research is in the search for frozen orbits.

  8. Plasma conditions at Europa's orbit

    NASA Astrophysics Data System (ADS)

    Bagenal, Fran; Sidrow, Evan; Wilson, Robert J.; Cassidy, Timothy A.; Dols, Vincent; Crary, Frank J.; Steffl, Andrew J.; Delamere, Peter A.; Kurth, William S.; Paterson, William R.

    2015-11-01

    With attention turned to Europa as a target for exploration, we focus on the space environment in which Europa is embedded. We review remote and in situ observations of plasma properties at Europa's orbit, between Io's dense, UV-emitting plasma torus and Jupiter's dynamic plasma sheet. Where observations are limited (e.g. in plasma composition), we supplement our analysis with models of the neutral and plasma populations from Io to Europa. We evaluate variations and uncertainties in plasma properties with radial distance, latitude, longitude and time. If we consider only the EUV channel of UVIS, the spectral emissions model concludes that O(III) is the dominant ionization state of oxygen in the Io torus. This unphysical result occurs because the model maximizes the amount of O(III) in order to minimize the model/spectrum discrepancy at 702 Å. With the inclusion of the FUV channel, there are two additional O(III) spectral lines located at 1661 and 1666 Å. These lines, first detected in the Io torus by Moos et al. (1991), place a strong constraint on the amount of O(III) present in the torus. Unfortunately, they are relatively faint and barely above the level of noise in the UVIS spectra. Therefore, the values we derive for the mixing ratio of O(III) or O(II) as a function of radial distance should more properly be thought of as an upper or lower limit on the actual value. With this caveat in mind, there is still significantly more O(III) and less O(II) compared to the Voyager model of Bagenal (1994). The [O(II)]/[O(III)] ratio, averaged over 6.2-8.8 RJ, is 3.7 - less than half the corresponding value of 8.8 from Bagenal (1994). The value of this ratio generally decreases with increasing radial distance, which is consistent with the observed increase in electron temperature.Note that the Bagenal (1994) oxygen composition came from Bagenal et al. (1992), which was based on the limited spectral range of the Voyager UVS

  9. Europa as an Abode of Life

    NASA Astrophysics Data System (ADS)

    Chyba, Christopher F.; Phillips, Cynthia B.

    2002-02-01

    Life as we know it on Earth depends on liquid water, a suite of `biogenic' elements (most famously carbon) and a useful source of free energy. Here we review Europa's suitability for life from the perspective of these three requirements. It is likely, though not yet certain, that Europa harbors a subsurface ocean of liquid water whose volume is about twice that of Earth's oceans. Little is known about Europa's inventory of carbon, nitrogen, and other biogenic elements, but lower bounds on these can be placed by considering the role of cometary delivery over Europa's history. Sources of free energy are challenging for a world covered with an ice layer kilometers thick, but it is possible that hydrothermal activity and/or organics and oxidants provided by the action of radiation chemistry at Europa's surface and subsequent mixing into Europa's ocean could provide the electron donors and acceptors needed to power a Europan ecosystem. It is not premature to draw lessons from the search for life on Mars with the Viking spacecraft for planning exobiological missions to Europa.

  10. Thick or Thin Ice Shell on Europa?

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Scientists are all but certain that Europa has an ocean underneath its icy surface, but they do not know how thick this ice might be. This artist concept illustrates two possible cut-away views through Europa's ice shell. In both, heat escapes, possibly volcanically, from Europa's rocky mantle and is carried upward by buoyant oceanic currents. If the heat from below is intense and the ice shell is thin enough (left), the ice shell can directly melt, causing what are called 'chaos' on Europa, regions of what appear to be broken, rotated and tilted ice blocks. On the other hand, if the ice shell is sufficiently thick (right), the less intense interior heat will be transferred to the warmer ice at the bottom of the shell, and additional heat is generated by tidal squeezing of the warmer ice. This warmer ice will slowly rise, flowing as glaciers do on Earth, and the slow but steady motion may also disrupt the extremely cold, brittle ice at the surface. Europa is no larger than Earth's moon, and its internal heating stems from its eccentric orbit about Jupiter, seen in the distance. As tides raised by Jupiter in Europa's ocean rise and fall, they may cause cracking, additional heating and even venting of water vapor into the airless sky above Europa's icy surface. (Artwork by Michael Carroll.)

  11. Navigational Challenges for a Europa Flyby Mission

    NASA Technical Reports Server (NTRS)

    Martin-Mur, Tomas J.; Ionasescu, Rodica; Valerino, Powtawche; Criddle, Kevin; Roncoli, Ralph

    2014-01-01

    Jupiter's moon Europa is a prime candidate in the search for present-day habitable environments outside of the Earth. A number of missions have provided increasingly detailed images of the complex surface of Europa, including the Galileo mission, which also carried instruments that allowed for a limited investigation of the environment of Europa. A new mission to Europa is needed to pursue these exciting discoveries using close-up observations with modern instrumentation designed to address the habitability of Europa. In all likelihood the most cost effective way of doing this would be with a spacecraft carrying a comprehensive suite of instruments and performing multiple flybys of Europa. A number of notional trajectory designs have been investigated, utilizing gravity assists from other Galilean moons to decrease the period of the orbit and shape it in order to provide a globally distributed coverage of different regions of Europa. Navigation analyses are being performed on these candidate trajectories to assess the total Delta V that would be needed to complete the mission, to study how accurately the flybys could be executed, and to determine which assumptions most significantly affect the performance of the navigation system.

  12. Characteristics and comprehensiveness of adult HIV care and treatment programmes in Asia-Pacific, sub-Saharan Africa and the Americas: results of a site assessment conducted by the International epidemiologic Databases to Evaluate AIDS (IeDEA) Collaboration

    PubMed Central

    Duda, Stephany N; Farr, Amanda M; Lindegren, Mary Lou; Blevins, Meridith; Wester, C William; Wools-Kaloustian, Kara; Ekouevi, Didier K; Egger, Matthias; Hemingway-Foday, Jennifer; Cooper, David A; Moore, Richard D; McGowan, Catherine C; Nash, Denis

    2014-01-01

    Introduction HIV care and treatment programmes worldwide are transforming as they push to deliver universal access to essential prevention, care and treatment services to persons living with HIV and their communities. The characteristics and capacity of these HIV programmes affect patient outcomes and quality of care. Despite the importance of ensuring optimal outcomes, few studies have addressed the capacity of HIV programmes to deliver comprehensive care. We sought to describe such capacity in HIV programmes in seven regions worldwide. Methods Staff from 128 sites in 41 countries participating in the International epidemiologic Databases to Evaluate AIDS completed a site survey from 2009 to 2010, including sites in the Asia-Pacific region (n=20), Latin America and the Caribbean (n=7), North America (n=7), Central Africa (n=12), East Africa (n=51), Southern Africa (n=16) and West Africa (n=15). We computed a measure of the comprehensiveness of care based on seven World Health Organization-recommended essential HIV services. Results Most sites reported serving urban (61%; region range (rr): 33–100%) and both adult and paediatric populations (77%; rr: 29–96%). Only 45% of HIV clinics that reported treating children had paediatricians on staff. As for the seven essential services, survey respondents reported that CD4+ cell count testing was available to all but one site, while tuberculosis (TB) screening and community outreach services were available in 80 and 72%, respectively. The remaining four essential services – nutritional support (82%), combination antiretroviral therapy adherence support (88%), prevention of mother-to-child transmission (PMTCT) (94%) and other prevention and clinical management services (97%) – were uniformly available. Approximately half (46%) of sites reported offering all seven services. Newer sites and sites in settings with low rankings on the UN Human Development Index (HDI), especially those in the President's Emergency Plan

  13. Comparison of Ridges on Triton and Europa

    NASA Technical Reports Server (NTRS)

    Prockter, L. M.; Pappalardo, R. .

    2003-01-01

    Triton and Europa each display a variety of ridges and associated troughs. The resemblance of double ridges on these two satellites has been previously noted [R. Kirk, pers. comm.], but as yet, the similarities and differences between these feature types have not been examined in any detail. Triton s ridges, and Europa s, exhibit an evolutionary sequence ranging from isolated troughs, through doublet ridges, to complex ridge swaths [1, 2]. Comparison of ridges on Europa to those on Triton may provide insight into their formation on both satellites, and thereby have implications for the satellites' histories.

  14. Automated Design of the Europa Orbiter Tour

    NASA Technical Reports Server (NTRS)

    Heaton, Andrew F.; Strange, Nathan J.; Longuski, James M.; Bonfiglio, Eugene P.; Taylor, Irene (Technical Monitor)

    2000-01-01

    In this paper we investigate tours of the Jovian satellites Europa Ganymede, and Callisto for the Europa Orbiter Mission. The principal goal of the tour design is to lower arrival V_ for the final Europa encounter while meeting all of the design constraints. Key constraints arise from considering the total time of the tour and the radiation dosage of a tour. These tours may employ 14 or more encounters with the Jovian satellites. hence there is an enormous number of possible sequences of these satellites to investigate. We develop a graphical method that greatly aids the design process.

  15. Automated Design of the Europa Orbiter Tour

    NASA Technical Reports Server (NTRS)

    Heaton, Andrew F.; Strange, Nathan J.; Longusaki, James M.; Bonfiglio, Eugene P.

    2000-01-01

    In this paper we investigate tours of the Jovian satellites Europa, Ganymede, and Callisto for the Europa Orbiter Mission. The principal goal of the tour design is to lower arrival V(sub infinity) for the final Europa encounter while meeting all of the design constraints. Key constraints arise from considering the total time of the tour and the radiation dosage of a tour. These tours may employ 14 or more encounters with the Jovian satellites, hence there is an enormous number of possible sequences of these satellites to investigate. We develop a graphical method that greatly aids the design process.

  16. Asia Lakes

    Atmospheric Science Data Center

    2013-04-16

    article title:  Central Asia - Mongolia, China and Russia     View Larger ... Imaging SpectroRadiometer (MISR) image of Mongolia, China and Russia covers an area of about 317 kilometers x 412 kilometers, and ...

  17. A Dark Spot on Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This view taken by NASA's Galileo spacecraft of Jupiter's icy moon Europa focuses on a dark, smooth region whose center is the lowest area in this image. To the west (left), it is bounded by a cliff and terraces, which might have been formed by normal faulting. The slopes toward the east (right) leading into the dark spot are gentle.

    Near the center of the dark area, it appears the dark materials have covered some of the bright terrain and ridges. This suggests that when the dark material was deposited, it may have been a fluid or an icy slush.

    Only a few impact craters are visible, with some of them covered or flooded by dark material. Some appear in groups, which may indicate that they are secondary craters formed by debris excavated during a larger impact event. A potential source for these is the nearby crater Mannann`an.

    North is to the top of the picture which is centered at 1 degree south latitude and 225 degrees west longitude. The images in this mosaic have been re-projected to 50 meters (55 yards) per picture element. They were obtained by the Solid State Imaging (SSI) system on March 29, 1998, during Galileo's fourteenth orbit of Jupiter, at ranges as close as 1940 kilometers (1,200 miles) from Europa.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  18. Probing Europa's interior with natural sound sources

    NASA Astrophysics Data System (ADS)

    Lee, Sunwoong; Zanolin, Michele; Thode, Aaron M.; Pappalardo, Robert T.; Makris, Nicholas C.

    2003-09-01

    Europa's interior structure may be determined by relatively simple and robust seismo-acoustic echo sounding techniques. The strategy is to use ice cracking events or impacts that are hypothesized to occur regularly on Europa's surface as sources of opportunity. A single passive geophone on Europa's surface may then be used to estimate the thickness of its ice shell and the depth of its ocean by measuring the travel time of seismo-acoustic reflections from the corresponding internal strata. Quantitative analysis is presented with full-field seismo-acoustic modeling of the Europan environment. This includes models for Europan ambient noise and conditions on signal-to-noise ratio necessary for the proposed technique to be feasible. The possibility of determining Europa's ice layer thickness by surface wave and modal analysis with a single geophone is also investigated.

  19. MALDI for Europa Planetary Science and Exobiology

    NASA Technical Reports Server (NTRS)

    Wdowiak, T. J.; Agresti, D. G.; Clemett, S. J.

    2000-01-01

    TOF MS for Europa landed science can identify small molecules of the cryosphere and complex biomolecules upwelling from a subsurface water ocean. A matrix-assisted laser-desorption ionization (MALDI) testbed for cryo-ice mixtures is being developed.

  20. Formation of cycloidal features on Europa.

    PubMed

    Hoppa, G V; Tufts, B R; Greenberg, R; Geissler, P E

    1999-09-17

    Cycloidal patterns are widely distributed on the surface of Jupiter's moon Europa. Tensile cracks may have developed such a pattern in response to diurnal variations in tidal stress in Europa's outer ice shell. When the tensile strength of the ice is reached, a crack may occur. Propagating cracks would move across an ever-changing stress field, following a curving path to a place and time where the tensile stress was insufficient to continue the propagation. A few hours later, when the stress at the end of the crack again exceeded the strength, propagation would continue in a new direction. Thus, one arcuate segment of the cycloidal chain would be produced during each day on Europa. For this model to work, the tensile strength of Europa's ice crust must be less than 40 kilopascals, and there must be a thick fluid layer below the ice to allow sufficient tidal amplitude. PMID:10489365

  1. Europa's Thermal Surface from Galileo PPR

    NASA Astrophysics Data System (ADS)

    Rodriguez, N. J.; Rathbun, J. A.; Spencer, J. R.

    2009-03-01

    We present Galileo Photopolarimeter-Radiometer data of Europa and, from these, model the thermal inertia and bolometric albedo of the surface. We also derive an upper limit for detection of endogenic activity.

  2. Constraints on the subsurface structure of Europa

    NASA Astrophysics Data System (ADS)

    Golombek, M. P.; Banerdt, W. B.

    1990-02-01

    The wedge-shaped bands appearing near the anti-Jovian point on Europa are tension cracks which, after formation on an intact lithosphere, have facilitated the rotation of ice-lithosphere sections decoupled from the silicate interior. Such factors as fluid pressure, surface temperature, silicate impurities in the ice, and strain rates, would have affected the processes in question. A minimum degree of differentiation is required for Europa to mechanically decouple the rotated ice lithosphere from the underlying, predominantly silicate mantle.

  3. Hydrogen peroxide on the surface of Europa

    USGS Publications Warehouse

    Carlson, R.W.; Anderson, M.S.; Johnson, R.E.; Smythe, W.D.; Hendrix, A.R.; Barth, C.A.; Soderblom, L.A.; Hansen, G.B.; McCord, T.B.; Dalton, J.B.; Clark, R.N.; Shirley, J.H.; Ocampo, A.C.; Matson, D.L.

    1999-01-01

    Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis.

  4. Hydrogen peroxide on the surface of Europa.

    PubMed

    Carlson, R W; Anderson, M S; Johnson, R E; Smythe, W D; Hendrix, A R; Barth, C A; Soderblom, L A; Hansen, G B; McCord, T B; Dalton, J B; Clark, R N; Shirley, J H; Ocampo, A C; Matson, D L

    1999-03-26

    Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis. PMID:10092224

  5. Europa's Interaction with the Magnetosphere of Jupiter

    NASA Astrophysics Data System (ADS)

    Khurana, Krishan K.; Jia, Xianzhe; Paranicas, Chris; Cassidy, Timothy A.; Hansen, Kenneth C.

    2013-04-01

    Galileo's observations of magnetic field in the vicinity of Europa have shown that Europa does not possess an appreciable internal magnetic field. However, Europa strongly modifies its plasma and magnetic field environment by directly interacting with the magnetosphere of Jupiter. The plasma interactions cause the absorption of Jovian plasma by the moon, pick-up of newly formed ions from the exospheres of the moon, plasma diversion by electrodynamic (Alfvén wing) interaction and the formation of a long wake in the downstream region. In addition to the electrodynamic interactions, Europa also displays electromagnetic induction response to the rotating field of Jupiter presumably from the conducting presence of global salty liquid oceans inside the moon. Galileo successfully encountered Europa 10 times during its mission. We are developing quantitative 3-D MHD models of plasma interactions of Europa with Jupiter's magnetosphere. In these models we include the effects of plasma pick-up and plasma interaction with a realistic exosphere as well as the contribution of the electromagnetic induction. We will present results of these quantitative models and show that the plasma interaction is strongest when Europa is located at the center of Jupiter's current sheet. We find that plasma mass loading rates are extremely variable over time. We will investigate various mechanisms by which such variability in mass-loading could be produced including episodically enhanced sputtering from trapped gaseous molecules in ice and enhanced plasma interaction with a vent(s) generated dense exosphere. The new model will aid researchers in planning observations from future missions such as JUICE and Europa flagship mission.

  6. Modeling Europa's Ice-Ocean Interface

    NASA Astrophysics Data System (ADS)

    Elsenousy, A.; Vance, S.; Bills, B. G.

    2014-12-01

    This work focuses on modeling the ice-ocean interface on Jupiter's Moon (Europa); mainly from the standpoint of heat and salt transfer relationship with emphasis on the basal ice growth rate and its implications to Europa's tidal response. Modeling the heat and salt flux at Europa's ice/ocean interface is necessary to understand the dynamics of Europa's ocean and its interaction with the upper ice shell as well as the history of active turbulence at this area. To achieve this goal, we used McPhee et al., 2008 parameterizations on Earth's ice/ocean interface that was developed to meet Europa's ocean dynamics. We varied one parameter at a time to test its influence on both; "h" the basal ice growth rate and on "R" the double diffusion tendency strength. The double diffusion tendency "R" was calculated as the ratio between the interface heat exchange coefficient αh to the interface salt exchange coefficient αs. Our preliminary results showed a strong double diffusion tendency R ~200 at Europa's ice-ocean interface for plausible changes in the heat flux due to onset or elimination of a hydrothermal activity, suggesting supercooling and a strong tendency for forming frazil ice.

  7. Plasma ion composition measurements for Europa

    NASA Astrophysics Data System (ADS)

    Sittler, E. C.; Cooper, J. F.; Hartle, R. E.; Paterson, W. R.; Christian, E. R.; Lipatov, A. S.; Mahaffy, P. R.; Paschalidis, N. P.; Coplan, M. A.; Cassidy, T. A.; Richardson, J. D.; Fegley, B.; Andre, N.

    2013-11-01

    Jupiter magnetospheric interactions and surface composition, both important to subsurface ocean detection for the Galilean icy moons Europa, Ganymede, and Callisto, can be measured using plasma ion mass spectrometry on either an orbiting spacecraft or one designed for multiple flybys of these moons. Detection of emergent oceanic materials at the Europa surface is more likely than at Ganymede and Callisto. A key challenge is to resolve potential intrinsic Europan materials from the space weathering patina of iogenic species implanted onto the sensible surface by magnetospheric interactions. Species-resolved measurements of pickup ion currents are also critical to extraction of oceanic induced magnetic fields from magnetospheric interaction background dominated by these currents. In general the chemical astrobiological potential of Europa should be determined through the combination of surface, ionospheric, and pickup ion composition measurements. The requisite Ion Mass Spectrometer (IMS) for these measurements would need to work in the high radiation environment of Jupiter's magnetosphere between the orbits of Europa and Ganymede, and beyond. A 3D hybrid model of the moon-magnetosphere interaction is also needed to construct a global model of the electric and magnetic fields, and the plasma environment, around Europa. Europa's ionosphere is probably usually dominated by hot pickup ions with 100-1000 eV temperatures, excursions to a "classical" cold ionosphere likely being infrequent. A field aligned ionospheric wind driven by the electron polarization electric field should arise and be measurable.

  8. Who Is a Typical Patient with Visceral Leishmaniasis? Characterizing the Demographic and Nutritional Profile of Patients in Brazil, East Africa, and South Asia

    PubMed Central

    Harhay, Michael O.; Olliaro, Piero L.; Vaillant, Michel; Chappuis, François; Lima, María Angeles; Ritmeijer, Koert; Costa, Carlos Henrique; Costa, Dorcas Lamounier; Rijal, Suman; Sundar, Shyam; Balasegaram, Manica

    2011-01-01

    Drug-dosing recommendations for visceral leishmaniasis (VL) treatment are based on the patients' weight or age. A current lack of demographic and anthropometric data on patients hinders (1) the ability of health providers to properly prepare for patient management, (2) an informed drug procurement for disease control, and (3) the design of clinical trials and development of new drug therapies in the different endemic areas. We present information about the age, gender, weight, and height of 29,570 consecutive VL patients presenting to 20 locations in six geographic endemic regions of Brazil, East Africa, Nepal, and India between 1997 and 2009. Our compilation shows substantial heterogeneity in the types of patients seeking care for VL at the clinics within the different locations. This suggests that drug development, procurement, and perhaps even treatment protocols, such as the use of the potentially teratogenic drug miltefosine, may require distinct strategies in these geographic settings. PMID:21460007

  9. Europa: Prospects for an ocean and exobiological implications

    NASA Technical Reports Server (NTRS)

    Oro, John; Squyres, Steven W.; Reynolds, Ray T.; Mills, Thomas M.

    1992-01-01

    As far as we know, Earth is the only planet in our solar system that supports life. It is natural, therefore, that our understanding of life as a planetary phenomenon is based upon Earth-like planets. There are environments in the solar system where liquid water, commonly believed to be a prerequisite for biological activity, may exist in a distinctly non-Earth-like environment. One such location is Europa, one of the Galilean satellites of Jupiter. The possibility that liquid water exists on Europa presents us with some interesting exobiological implications concerning the potential of the satellite to support life. Topics include the following: an ocean on Europa; thermal evolution of Europa; Europa's three models; exobiological implications; early conditions of Europa; low-temperature abiotic chemistry; possibility of the emergence of life on Europa; prerequisites for the habitability of Europa; energy sources for biosynthesis and metabolic activity; habitability of Europa by anaerobic life; and habitability by aerobic life.

  10. Scientific Rationale for Study Design of Community-based Simplified Antibiotic Therapy Trials in Newborns and Young Infants With Clinically Diagnosed Severe Infections or Fast Breathing in South Asia and sub-Saharan Africa

    PubMed Central

    2013-01-01

    Background: Newborns and young infants suffer high rates of infections in South Asia and sub-Saharan Africa. Timely access to appropriate antibiotic therapy is essential for reducing mortality. In an effort to develop community case management guidelines for young infants, 0–59 days old, with clinically diagnosed severe infections, or with fast breathing, 4 trials of simplified antibiotic therapy delivered in primary care clinics (Pakistan, Democratic Republic of Congo, Kenya and Nigeria) or at home (Bangladesh and Nigeria) are being conducted. Methods: This article describes the scientific rationale for these trials, which share major elements of trial design. All the trials are in settings of high neonatal mortality, where hospitalization is not feasible or frequently refused. All use procaine penicillin and gentamicin intramuscular injections for 7 days as reference therapy and compare this to various experimental arms utilizing comparatively simpler combination regimens with fewer injections and oral amoxicillin. Conclusion: The results of these trials will inform World Health Organization policy regarding community case management of young infants with clinical severe infections or with fast breathing. PMID:23945577

  11. Ocean Compositions on Europa and Ganymede

    NASA Astrophysics Data System (ADS)

    Leitner, M. A.; Bothamy, N.; Choukroun, M.; Pappalardo, R. T.; Vance, S.

    2014-12-01

    The ocean compositions of icy Galilean satellites Europa and Ganymede are highly uncertain. Spectral observations of the satellites' surfaces provide clues for the interior composition. Putative sulfate hydration features in Galileo near-infrared reflectance spectra suggest fractionation of Na and Mg sulfates from a subsurface reservoir (McCord et al. 1998, Sci. 278, 271; McCord et al. 1998, Sci. 280, 1242; Dalton et al. 2005, Icarus, 177, 472). Recent spatially resolved spectral mapping of Europa hints at possible partitioning of near-surface brines in Europa's low-lying planes (Shirley et al. 2010; Icarus, 210, 358; Dalton et al. 2012; J. Geophys. Res. 117, E03003). Surface materials can be modified by the delivery of material from impacts and Io's active volcanoes as well as intense irradiation from Jupiter's magnetic field interaction with the jovian magnetosphere. These factors, combined with observations of high Cl/K ratios in Europa's exosphere, have led other investigators to suggest that Europa's ocean is dominated by dissolved chloride rather than sulfate (Brown and Hand 2013; Astr. J. 145, 110). There is still much uncertainty regarding how well the surface composition approximates the interior ocean composition. Exogenic materials, seafloor hydrothermal processes, and fractional crystallization during ice formation will determine the abundances of species in the ocean and by extension those present on Europa's surface. We develop a bottom-up model for oceans on Europa and Ganymede, assuming initial compositions of chondritic and cometary materials including an Fe core for Europa and an Fe-FeS eutectic core for Ganymede. We calculate an ocean composition by employing a Bulk Silicate Earth approach, also used by Zolotov and Shock (2001; J. Geophys. Res. 106, 32815) at Europa, which assess element partitioning between the rocky mantle, Fe-rich core, and water ocean. Partitioning factors are based on terrestrial estimates for Earth. The resulting ocean

  12. Oceans, Ice Shells, and Life on Europa

    NASA Technical Reports Server (NTRS)

    Schenk, Paul

    2002-01-01

    The four large satellites of Jupiter are famous for their planet-like diversity and complexity, but none more so than ice-covered Europa. Since the provocative Voyager images of Europa in 1979, evidence has been mounting that a vast liquid water ocean may lurk beneath the moon's icy surface. Europa has since been the target of increasing and sometimes reckless speculation regarding the possibility that giant squid and other creatures may be swimming its purported cold, dark ocean. No wonder Europa tops everyone's list for future exploration in the outer solar system (after the very first reconnaissance of Pluto and the Kuiper belt, of course). Europa may be the smallest of the Galilean moons (so-called because they were discovered by Galileo Galilei in the early 17th century) but more than makes up for its diminutive size with a crazed, alien landscape. The surface is covered with ridges hundreds of meters high, domes tens of kilometers across, and large areas of broken and disrupted crust called chaos. Some of the geologic features seen on Europa resemble ice rafts floating in polar seas here on Earth-reinforcing the idea that an ice shell is floating over an ocean on this Moon-size satellite. However, such features do not prove that an ocean exists or ever did. Warm ice is unusually soft and will flow under its own weight. If the ice shell is thick enough, the warm bottom of the shell will flow, as do terrestrial glaciers. This could produce all the observed surface features on Europa through a variety of processes, the most important of which is convection. (Convection is the vertical overturn of a layer due to heating or density differences-think of porridge or sauce boiling on the stove.) Rising blobs from the base of the crust would then create the oval domes dotting Europa's surface. The strongest evidence for a hidden ocean beneath Europa's surface comes from the Galileo spacecraft's onboard magnetometer, which detected fluctuations in Jupiter's magnetic

  13. Europa Ridges, Hills and Domes

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This moderate-resolution view of the surface of one of Jupiter's moons, Europa, shows the complex icy crust that has been extensively modified by fracturing and the formation of ridges. The ridge systems superficially resemble highway networks with overpasses, interchanges and junctions. From the relative position of the overlaps, it is possible to determine the age sequence for the ridge sets. For example, while the 8-kilometer-wide (5-mile) ridge set in the lower left corner is younger than most of the terrain seen in this picture, a narrow band cuts across the set toward the bottom of the picture, indicating that the band formed later. In turn, this band is cut by the narrow 2- kilometer-wide (1.2-mile) double ridge running from the lower right to upper left corner of the picture. Also visible are numerous clusters of hills and low domes as large as 9 kilometers (5.5 miles) across, many with associated dark patches of non-ice material. The ridges, hills and domes are considered to be ice-rich material derived from the subsurface. These are some of the youngest features seen on the surface of Europa and could represent geologically young eruptions.

    This area covers about 140 kilometers by 130 kilometers (87 miles by 81 miles) and is centered at 12.3 degrees north latitude, 268 degrees west longitude. Illumination is from the east (right side of picture). The resolution is about 180 meters (200 yards) per pixel, meaning that the smallest feature visible is about a city block in size. The picture was taken by the Solid State Imaging system on board the Galileo spacecraft on February 20, 1997, from a distance of 17,700 kilometers (11,000 miles) during its sixth orbit around Jupiter.

    The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington D.C. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov.

  14. Comparative Tectonics of Europa and Ganymede

    NASA Astrophysics Data System (ADS)

    Pappalardo, R. T.; Collins, G. C.; Prockter, L. M.; Head, J. W.

    2000-10-01

    Europa and Ganymede are sibling satellites with tectonic similarities and differences. Ganymede's ancient dark terrain is crossed by furrows, probably related to ancient large impacts, and has been normal faulted to various degrees. Bright grooved is pervasively deformed at multiple scales and is locally highly strained, consistent with normal faulting of an ice-rich lithosphere above a ductile asthenosphere, along with minor horizontal shear. Little evidence has been identified for compressional structures. The relative roles of tectonism and icy cryovolcanism in creating bright grooved terrain is an outstanding issue. Some ridge and trough structures within Europa's bands show tectonic similarities to Ganymede's grooved terrain, specifically sawtooth structures resembling normal fault blocks. Small-scale troughs are consistent with widened tension fractures. Shearing has produced transtensional and transpressional structures in Europan bands. Large-scale folds are recognized on Europa, with synclinal small-scale ridges and scarps probably representing folds and/or thrust blocks. Europa's ubiquitous double ridges may have originated as warm ice upwelled along tidally heated fracture zones. The morphological variety of ridges and troughs on Europa imply that care must be taken in inferring their origin. The relative youth of Europa's surface means that the satellite has preserved near-pristine morphologies of many structures, though sputter erosion could have altered the morphology of older topography. Moderate-resolution imaging has revealed lesser apparent diversity in Ganymede's ridge and trough types. Galileo's 28th orbit has brought new 20 m/pixel imaging of Ganymede, allowing direct comparison to Europa's small-scale structures.

  15. Radiation Chemistry of Potential Europa Plumes

    NASA Astrophysics Data System (ADS)

    Gudipati, M. S.; Henderson, B. L.

    2014-12-01

    Recent detection of atomic hydrogen and atomic oxygen and their correlation to potential water plumes on Europa [Roth, Saur et al. 2014] invoked significant interest in further understanding of these potential/putative plumes on Europa. Unlike on Enceladus, Europa receives significant amount of electron and particle radiation. If the plumes come from trailing hemisphere and in the high radiation flux regions, then it is expected that the plume molecules be subjected to radiation processing. Our interest is to understand to what extent such radiation alterations occur and how they can be correlated to the plume original composition, whether organic or inorganic in nature. We will present laboratory studies [Henderson and Gudipati 2014] involving pulsed infrared laser ablation of ice that generates plumes similar to those observed on Enceladus [Hansen, Esposito et al. 2006; Hansen, Shemansky et al. 2011] and expected to be similar on Europa as a starting point; demonstrating the applicability of laser ablation to simulate plumes of Europa and Enceladus. We will present results from electron irradiation of these plumes to determine how organic and inorganic composition is altered due to radiation. Acknowledgments:This research was enabled through partial funding from NASA funding through Planetary Atmospheres, and the Europa Clipper Pre-Project. B.L.H. acknowledges funding from the NASA Postdoctoral Program for an NPP fellowship. Hansen, C. J., L. Esposito, et al. (2006). "Enceladus' water vapor plume." Science 311(5766): 1422-1425. Hansen, C. J., D. E. Shemansky, et al. (2011). "The composition and structure of the Enceladus plume." Geophysical Research Letters 38. Henderson, B. L. and M. S. Gudipati (2014). "Plume Composition and Evolution in Multicomponent Ices Using Resonant Two-Step Laser Ablation and Ionization Mass Spectrometry." The Journal of Physical Chemistry A 118(29): 5454-5463. Roth, L., J. Saur, et al. (2014). "Transient Water Vapor at Europa's South

  16. Viscoelastic Membrane Tectonics on Europa

    NASA Astrophysics Data System (ADS)

    Beuthe, M.; Rivoldini, A.

    2014-12-01

    The surface of Europa is crisscrossed by tectonic features generally attributed to time-dependent tidal deformations. For a long time, the membrane theory of elastic shells (thin shell or flattening model) has been popular to predict tidal tectonic patterns because it provides simple analytical formulas for tidal stresses. More recently, the theory of viscoelastic-gravitational deformations (or thick shell model) was applied to tidal tectonics so as to include viscoelastic effects. This method, however, is not transparent to the user and relies on numerical algorithms that are not always publicly available or fully benchmarked. As an alternative, we propose here to extend membrane theory to viscoelastic shells with depth-dependent rheology. Viscoelasticity is taken into account by replacing elastic constants with effective viscoelastic parameters that are easily computed for a given rheology. The membrane approach thus leads to simple formulas for viscoelastic tidal stresses. Because of its formulation in terms of tidal Love numbers, the membrane approach has clear relationships with both thin and thick shell models. Benchmarking with the thick-shell software SatStress leads to the discovery of an error in that code that changes stress components by up to 40%. As an application, we show that different stress-free states account for the conflicting predictions of thin and thick shell models about the magnitude of tensile stresses due to nonsynchronous rotation.

  17. Various Landscapes and Features on Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    These 15 frames show the great variety of surface features on Jupiter's icy moon, Europa, which have been revealed by the Galileo spacecraft Solid State Imaging (CCD) system during its first six orbits around Jupiter from June 1996 to February 1997. North is to the top of each of the images. The features seen on Europa's surface document both internal and external processes shaping the icy crust. Internal processes and the possible presence of liquid water beneath the ice are indicated by features such as 'dark spots', lobe-shaped flow features, 'puddles','mottled terrain', knobs, pits, and the darker areas along ridges and triple bands.

    Europa is subjected to constant tugging from the giant planet, Jupiter, as well as from its neighboring moons, Io and Ganymede. This causes 'tidal' forces that affect Europa's interior and surface. Evidence for such forces includes ridges, fractures, wedge-shaped bands, and areas of 'chaos'. Some of these features result from alternate extension and compression buckling and pulling apart Europa's icy shell.

    Impact craters document external effects on a planet's surface. Although present on Europa, impact craters are relatively scarce compared to the number seen on Ganymede, Callisto, and on the surfaces of most other 'rocky' planets and moons in our solar system. This scarcity of craters suggests that the surface of Europa is very young. 'Maculae' on Europa may be the scars from large impact events.

    These images have resolutions from 27 meters (89 feet) to 7 kilometers (4.3 miles) per picture element (pixel) and were taken by Galileo at ranges of 2,500 kilometers (1,525 miles) to 677,000 kilometers (413,000 miles) from Europa.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web

  18. Value of children and fertility: Results from a cross-cultural comparative survey in eighteen areas in Asia, Africa, Europe and America.

    PubMed

    Nauck, Bernhard

    2014-09-01

    For explaining cross-cultural differences in fertility behavior, this paper conjoins three complementary approaches: the 'demand'-based economic theory of fertility (ETF), a revised version of the 'supply'-based 'value-of-children' (VOC)-approach as a special theory of the general social theory of social production functions and the framing theory of variable rationality. A comprehensive model is specified that encompasses the variable efficiency of having children for the optimization of physical well-being and of social esteem of (potential) parents; it also accounts for the variable rationality of fertility decisions. The model is tested with a data set that comprises information on VOC and fertility of women within the social settings of 18 areas (Peoples Republic of China, North and South India, Indonesia, Palestine, Israel, Turkey, Ghana, South Africa, East and West Germany, the Czech Republic, France, Russia, Poland, Estonia, the United States and Jamaica). Latent class analysis is used to establish a measurement model for the costs and benefits of children and to analyze area differences by a two-level multinomial-model. Two-level Cox-regressions are used to estimate the effects of perceived costs and benefits of children, individual resources and context opportunities, with births of different parity as dependents. This simultaneous test in a cross-cultural context goes beyond the current state of fertility research and provides evidence about the cross-cultural validity of the model, the systematic effects of VOC on fertility and the changing rationality of fertility decisions during demographic transition and socio-economic change. PMID:26047548

  19. EUROPA Multiple-Flyby Trajectory Design

    NASA Technical Reports Server (NTRS)

    Buffington, Brent; Campagnola, Stefano; Petropoulos, Anastassios

    2012-01-01

    As reinforced by the 2011 NRC Decadal Survey, Europa remains one of the most scientifically intriguing targets in planetary science due to its potential suitability for life. However, based on JEO cost estimates and current budgetary constraints, the Decadal Survey recommended-and later directed by NASA Headquarters-a more affordable pathway to Europa exploration be derived. In response, a flyby-only proof-of-concept trajectory has been developed to investigate Europa. The trajectory, enabled by employing a novel combination of new mission design techniques, successfully fulfills a set of Science Definition Team derived scientific objectives carried out by a notional payload including ice penetrating radar, topographic imaging, and short wavelength infrared observations, and ion neutral mass spectrometry in-situ measurements. The current baseline trajectory, referred to as 11-F5, consists of 34 Europa and 9 Ganymede flybys executed over the course of 2.4 years, reached a maximum inclination of 15 degrees, has a deterministic delta v of 157 m/s (post-PJR), and has a total ionizing dose of 2.06 Mrad (Si behind 100 mil Al, spherical shell). The 11-F5 trajectory and more generally speaking, flyby-only trajectories-exhibit a number of potential advantages over an Europa orbiter mission.

  20. Heat transfer of ascending cryomagma on Europa

    NASA Astrophysics Data System (ADS)

    Quick, Lynnae C.; Marsh, Bruce D.

    2016-06-01

    Jupiter's moon Europa has a relatively young surface (60-90 Myr on average), which may be due in part to cryovolcanic processes. Current models for both effusive and explosive cryovolcanism on Europa may be expanded and enhanced by linking the potential for cryovolcanism at the surface to subsurface cryomagmatism. The success of cryomagma transport through Europa's crust depends critically on the rate of ascent relative to the rate of solidification. The final transport distance of cryomagma is thus governed by initial melt volume, ascent rate, overall ascent distance, transport mechanism (i.e., diapirism, diking, or ascent in cylindrical conduits), and melt temperature and composition. The last two factors are especially critical in determining the budget of expendable energy before complete solidification. Here we use these factors as constraints to explore conditions under which cryomagma may arrive at Europa's surface to facilitate cryovolcanism. We find that 1-5 km radius warm ice diapirs ascending from the base of a 10 km thick stagnant lid can reach the shallow subsurface in a partially molten state. Cryomagma transport may be further facilitated if diapirs travel along pre-heated ascent paths. Under certain conditions, cryolava transported from 10 km depths in tabular dikes or pipe-like conduits may reach the surface at temperatures exceeding 250 K. Ascent rates for these geometries may be high enough that isothermal transport is approached. Cryomagmas containing significant amounts of low eutectic impurities can also be delivered to Europa's surface by propagating dikes or pipe-like conduits.

  1. Stability of Frozen Orbits Around Europa

    NASA Astrophysics Data System (ADS)

    Cardoso Dos Santos, Josué; Vilhena de Moraes, R.; Carvalho, J. S.

    2013-05-01

    Abstract (2,250 Maximum Characters): A planetary satellite of interest at the present moment for the scientific community is Europa, one of the four largest moons of Jupiter. There are some missions planned to visit Europa in the next years, for example, Jupiter Europa Orbiter (JEO, NASA) and Jupiter IcyMoon Explorer (JUICE, ESA). In this work we are formulating theories and constructing computer programs to be used in the design of aerospace tasks as regards the stability of artificial satellite orbits around planetary satellites. The studies are related to translational motion of orbits around planetary satellites considering polygenic perturbations due to forces, such as the nonspherical shape of the central body and the perturbation of the third body. The equations of motion will be developed in closed form to avoid expansions in eccentricity and inclination. For a description of canonical formalism are used the Delaunay canonical variables. The canonical set of equations, which are nonlinear differential equations, will be used to study the stability of orbits around Europa. We will use a simplified dynamic model, which considers the effects caused by non-uniform distribution of mass of Europa (J2, J3 and C22) and the gravitational attraction of Jupiter. Emphasis will be given to the case of frozen orbits, defined as having almost constant values of eccentricity, inclination, and argument of pericentre. An approach will be used to search for frozen orbits around planetary satellites and study their stability by applying a process of normalization of Hamiltonian. Acknowledges: FAPESP

  2. Simulation of Na D emission near Europa during eclipse

    USGS Publications Warehouse

    Cassidy, T.A.; Johnson, R.E.; Geissler, P.E.; Leblanc, F.

    2008-01-01

    The Cassini imaging science subsystem observed Europa in eclipse during Cassini's Jupiter flyby. The disk-resolved observations revealed a spatially nonuniform emission in the wavelength range of 200-1050 nm (clear filters). By building on observations and simulations of Europa's Na atmosphere and torus we find that electron-excited Na in Europa's tenuous atmosphere can account for the observed emission if the Na is ejected preferentially from Europa's dark terrain. Copyright 2008 by the American Geophysical Union.

  3. Multicentre studies of insecticide-treated durable wall lining in Africa and South-East Asia: entomological efficacy and household acceptability during one year of field use

    PubMed Central

    2012-01-01

    Background Indoor residual spraying (IRS) is a primary method of malaria vector control, but its potential impact is constrained by several inherent limitations: spraying must be repeated when insecticide residues decay, householders can tire of the annual imposition and campaign costs are recurrent. Durable lining (DL) can be considered an advanced form of long-lasting IRS where insecticide is gradually released from an aesthetically attractive wall lining material to provide vector control for several years. A multicentre trial was carried out in Equatorial Guinea, Ghana, Mali, South Africa and Vietnam to assess the feasibility, durability, bioefficacy and household acceptability of DL, compared to conventional IRS or insecticide-treated curtains (LLITCs), in a variety of operational settings. Methods This study was conducted in 220 households in traditional rural villages over 12-15 months. In all sites, rolls of DL were cut to fit house dimensions and fixed to interior wall surfaces (usually with nails and caps) by trained teams. Acceptability was assessed using a standardized questionnaire covering such topics as installation, exposure reactions, entomology, indoor environment, aesthetics and durability. Bioefficacy of interventions was evaluated using WHO cone bioassay tests at regular intervals throughout the year. Results The deltamethrin DL demonstrated little to no decline in bioefficacy over 12-15 months, supported by minimal loss of insecticide content. By contrast, IRS displayed a significant decrease in bioactivity by 6 months and full loss after 12 months. The majority of participants in DL households perceived reductions in mosquito density (93%) and biting (82%), but no changes in indoor temperature (83%). Among those households that wanted to retain the DL, 73% cited protective reasons, 20% expressed a desire to keep theirs for decoration and 7% valued both qualities equally. In Equatorial Guinea, when offered a choice of vector control product at

  4. Very short-lived bromomethanes measured by the CARIBIC observatory over the North Atlantic, Africa and South-East Asia during 2009-2013

    NASA Astrophysics Data System (ADS)

    Wisher, A.; Oram, D. E.; Laube, J. C.; Mills, G. P.; van Velthoven, P.; Zahn, A.; Brenninkmeijer, C. A. M.

    2013-11-01

    Short-lived organic brominated compounds make up a significant part (~20%) of the organic bromine budget in the atmosphere. Emissions of these compounds are highly variable and there are limited measurements, particularly in the extra-tropical upper troposphere/lower stratosphere and tropical troposphere. Measurements of five short-lived bromomethanes (VSLB) were made in air samples collected on the CARIBIC project aircraft over three flight routes; Germany to Venezuela/Columbia during 2009-2011, Germany to South Africa during 2010 and 2011 and Germany to Thailand/Kuala Lumpur, Malaysia during 2012 and 2013. In the tropical troposphere, as the most important entrance region to the stratosphere, we observe a total mean organic bromine derived from these compounds across all flights at 10-12 km altitude of 3.4 ± 1.5 ppt. Individual mean tropical tropospheric mixing ratios across all flights were 0.43, 0.74, 0.14, 0.23 and 0.11 ppt for CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CH2BrCl respectively. The highest levels of VSLS-derived bromine (4.20 ± 0.56 ppt) were observed in flights between Bangkok and Kuala Lumpur indicating that the South China Sea is an important source region for these compounds. Across all routes, CHBr3 and CH2Br2 accounted for 34% (4.7-71) and 48% (14-73) respectively of total bromine derived from the analysed VSLB in the tropical mid-upper troposphere totalling 82% (54-89). In samples collected between Germany and Venezuela/Columbia, we find decreasing mean mixing ratios with increasing potential temperature in the extra-tropics. Tropical mean mixing ratios are higher than extra-tropical values between 340-350 K indicating that rapid uplift is important in determining mixing ratios in the lower tropical tropopause layer in the West Atlantic tropics. O3 was used as a tracer for stratospherically influenced air and we detect rapidly decreasing mixing ratios for all VSLB above ~100 ppb O3 corresponding to the extra-tropical tropopause layer.

  5. Very short-lived bromomethanes measured by the CARIBIC observatory over the North Atlantic, Africa and Southeast Asia during 2009-2013

    NASA Astrophysics Data System (ADS)

    Wisher, A.; Oram, D. E.; Laube, J. C.; Mills, G. P.; van Velthoven, P.; Zahn, A.; Brenninkmeijer, C. A. M.

    2014-04-01

    Short-lived organic brominated compounds make up a significant part of the organic bromine budget in the atmosphere. Emissions of these compounds are highly variable and there are limited measurements, particularly in the extra-tropical upper troposphere/lower stratosphere and tropical troposphere. Measurements of five very short-lived bromomethanes (VSLB) were made in air samples collected on the CARIBIC project aircraft over three flight routes; Germany to Venezuela/Columbia during 2009-2011, Germany to South Africa during 2010 and 2011 and Germany to Thailand/Kuala Lumpur, Malaysia during 2012 and 2013. In the tropical troposphere, as the most important entrance region to the stratosphere, we observe a total mean organic bromine derived from these compounds across all flights at 10-12 km altitude of 3.4 ± 1.5 ppt. Individual mean tropical tropospheric mixing ratios across all flights were 0.43, 0.74, 0.14, 0.23 and 0.11 ppt for CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CH2BrCl respectively. The highest levels of VSLB-derived bromine (4.20 ± 0.56 ppt) were observed in flights between Bangkok and Kuala Lumpur indicating that the South China Sea is an important source region for these compounds. Across all routes, CHBr3 and CH2Br2 accounted for 34% (4.7-71) and 48% (14-73) respectively of total bromine derived from the analysed VSLB in the tropical mid-upper troposphere totalling 82% (54-89). In samples collected between Germany and Venezuela/Columbia, we find decreasing mean mixing ratios with increasing potential temperature in the extra-tropics. Tropical mean mixing ratios are higher than extra-tropical values between 340-350 K indicating that rapid uplift is important in determining mixing ratios in the lower tropical tropopause layer in the West Atlantic tropics. O3 was used as a tracer for stratospherically influenced air and we detect rapidly decreasing mixing ratios for all VSLB above ∼100 ppb O3 corresponding to the extra-tropical tropopause layer.

  6. Transient water vapor at Europa's south pole.

    PubMed

    Roth, Lorenz; Saur, Joachim; Retherford, Kurt D; Strobel, Darrell F; Feldman, Paul D; McGrath, Melissa A; Nimmo, Francis

    2014-01-10

    In November and December 2012, the Hubble Space Telescope (HST) imaged Europa's ultraviolet emissions in the search for vapor plume activity. We report statistically significant coincident surpluses of hydrogen Lyman-α and oxygen OI 130.4-nanometer emissions above the southern hemisphere in December 2012. These emissions were persistently found in the same area over the 7 hours of the observation, suggesting atmospheric inhomogeneity; they are consistent with two 200-km-high plumes of water vapor with line-of-sight column densities of about 10(20) per square meter. Nondetection in November 2012 and in previous HST images from 1999 suggests varying plume activity that might depend on changing surface stresses based on Europa's orbital phases. The plume was present when Europa was near apocenter and was not detected close to its pericenter, in agreement with tidal modeling predictions. PMID:24336567

  7. Tides and the Biosphere of Europa

    NASA Astrophysics Data System (ADS)

    Greenberg, Richard

    2002-01-01

    It's been suspected for at least a decade now that Jupiter's icy moon Europa harbors a global ocean of liquid water beneath its crust. To many scientists the presence of another ocean in our solar system immediately conjured up images of extraterrestrial lifeforms swimming in an alien sea. But what sorts of life could evolve in the dark waters of a subsurface ocean, and how would it derive the energy it needs to survive? Planetary scientist, Richard Greenberg has been studying the surface features of Europa, and he finds that the icy crust that covers the ocean may not be as thick as scientists had at first supposed. Cracks in Europa's surface suggest that the ocean waters may come very close to the surface. If so, the cracks themselves may provide a niche for life, and the light near the surface of the moon could provide energy for photosynthetic organisms.

  8. Science and Reconnaissance from the Europa Clipper Mission Concept: Exploring Europa's Habitability

    NASA Astrophysics Data System (ADS)

    Pappalardo, Robert; Senske, David; Prockter, Louise; Paczkowski, Brian; Vance, Steve; Goldstein, Barry; Magner, Thomas; Cooke, Brian

    2015-04-01

    Europa is recognized by the Planetary Science De-cadal Survey as a prime candidate to search for a pre-sent-day habitable environment in our solar system. As such, NASA has pursued a series of studies, facilitated by a Europa Science Definition Team (SDT), to define a strategy to best advance our scientific understanding of this icy world with the science goal: Explore Europa to investigate its habitability. (In June of 2014, the SDT completed its task of identifying the overarching science objectives and investigations.) Working in concert with a technical team, a set of mission archi-tectures were evaluated to determine the best way to achieve the SDT defined science objectives. The fa-vored architecture would consist of a spacecraft in Ju-piter orbit making many close flybys of Europa, con-centrating on remote sensing to explore the moon. In-novative mission design would use gravitational per-turbations of the spacecraft trajectory to permit flybys at a wide variety of latitudes and longitudes, enabling globally distributed regional coverage of Europa's sur-face, with nominally 45 close flybys, typically at alti-tudes from 25 to 100 km. This concept has become known as the Europa Clipper. The Europa SDT recommended three science ob-jectives for the Europa Clipper: Ice Shell and Ocean: Characterize the ice shell and any subsurface water, including their heterogeneity, ocean properties, and the nature of surface-ice-ocean exchange; Composition: Understand the habitability of Europa's ocean through composition and chemistry; and Geology: Understand the formation of surface features, including sites of recent or current activity, and characterize high science interest localities. The Europa SDT also considered implications of the Hubble Space Telescope detection of possible plumes at Europa. To feed forward to potential subsequent future ex-ploration that could be enabled by a lander, it was deemed that the Europa Clipper mission concept should provide the

  9. Radiolytic Gas-Driven Cryovolcanism at Europa

    NASA Astrophysics Data System (ADS)

    Killen, R. M.; Cooper, J. F.; Sarantos, M.; Sittler, E. C., Jr.

    2014-12-01

    A large apparent plume of water vapor was detected at the south pole of Europa in December 2012 by the Hubble Space Telescope [Roth et al., 2014] when Europa was near maximum radial distance (apojove) in its orbit around Jupiter. The absence thus far of further detections both at apojove and elsewhere may indicate an episodic source. There was reportedly no evident brightening locally or globally of the Europa oxygen neutral atmosphere coincident with the plume water vapor detection. This could be consistent with an O2-driven cryovolcanism model in which bubbles of trapped gases in the ice crust are released from clathrates on thermal contact with rising oceanic water and expand to force upward fluid flows to the surface. It has long been suggested [Chyba, 2000; Cooper et al., 2001] that the Europa ocean could be oxygenated by radiolytic oxygen from surface irradiation, also implying that the overlying ice crust could be saturated in oxygen clathrates [Hand et al., 2006]. That the moon ocean could be a potentially habitable environment by oxygenation or other processes has been a major motivation for missions to Europa. The radiolytic gas source would be far greater at Europa as compared to much lesser source rates for a similar model at Enceladus [Cooper et al., 2009]. Detected plume emissions could arise from both the directly ejected vapor and from sputtering and/or sublimation of chemically-active plume frost in the polar cap region. Europa's surface gravity is much higher than that of Enceladus, so most of the plume vapor would return to the surface as frost. If sputtering or radiolysis were active contributors to polar cap emissions from the frost, then emissions could also maximize at 6.5-hour intervals as Europa passes through the densest part of the jovian magnetospheric plasma sheet as well as at 85-hour apojove intervals of the orbital period. For comparison to available polar cap plume and global atmospheric observations we present ballistic simulations

  10. Plumes on Enceladus: Lessons for Europa?

    NASA Astrophysics Data System (ADS)

    Nimmo, F.

    2014-12-01

    The possible detection of a water vapour plume on Europa [1] suggests resemblances to Enceladus, a cryovolcanically active satellite [2]. How does this activity work, and what lesson does Enceladus have for plumes on Europa? The inferred vapour column densities of the Europa [1] and Enceladus [3] plumes are similar, but the inferred velocity and mass flux of the former are higher. At Enceladus, the inferred plume strength is modulated by its orbital position [4,5], suggesting that tides opening and closing cracks control the eruption behaviour [6,7]. An additional source of stress potentially driving eruptions is the effect of slow freezing of the ice shell above[7,8]. The original detection of the Europa plume was close to apocentre, when polar fractures are expected to be in tension [1]. Follow-up observations at the same orbital phase did not detect a plume [9], although the Galileo E12 magnetometer data may provide evidence for an earlier plume [Khurana, pers. comm.]. One possible explanation for the plume's disappearance is that longer-period tidal effects are playing a role; there are hints of similar secular changes in the Enceladus data [4,5]. Another is that detectability of the Europa plumein the aurora observations also depends on variations in electron density (which affects the UV emission flux) [9]. Or it may simply be that eruptive activity on Europa is highly time-variable, as on Io. At Enceladus, the plume scale height is independent of orbital position and plume brightness [5]. This suggests that the vapour velocity does not depend on crack width, consistent with supersonic flow through a near-surface throat. The large scale height inferred for the Europa plume likewise suggests supersonic behaviour. Continuous fallback of solid plume material at Enceladus affects both the colour [10] and surface texture [2] of near-polar regions. Less frequent plume activity would produce subtler effects; whether the sparse available imagery at Europa [11

  11. Energetic particle fluxes in vicinity of Jupiter's moon Europa

    NASA Astrophysics Data System (ADS)

    Podzolko, Mikhail; Getselev, Igor; Gubar, Yuriy; Veselovsky, Igor

    Currently several projects of sending research space vehicles to Jupiter and its Galilean moons in 2020 are being developed. In particular, Russian Space Agency proposed the project of Europa lander. During the mission the spacecraft will be affected by charged particles of various origins. The greatest hazard will originate from powerful Jupiter's radiation belts, especially during the time of spacecraft operation near Europa and on its surface. The absorbed radiation dose during 2 months in Europa's orbit under shielding compared to that for "Galileo" spacecraft will amount to almost 1 megarad, the major contribution to it will originate from relativistic electrons. However, near Europa part of the charged particle flux will be shaded by the moon. Obviously, fluxes of particles of all energies on its surface will be lower by at least 2 times, than in the same point of space without Europa. But furthermore, the reduction of the fluxes in vicinity of Europa is nonuniform, and differs for the surface and the low-altitude orbit. This is caused by several factors: the complexity of particle trajectories near Europa and in Jupiter's magnetosphere in general, difference of Europa's orbital plane from Jupiter's geomagnetic equator plane, certain disturbance of Jupiter's magnetic field in vicinity of Europa, possible influence of electric fields and Europa's tenuous atmosphere. In the current study computations of energetic particle flux distribution near Europa and on its surface are made, taking into account several of the above-mentioned factors.

  12. Is Europa's Subsurface Water Ocean Warm?

    NASA Technical Reports Server (NTRS)

    Melosh, H. J.; Ekholm, A. G.; Showman, A. P.; Lorenz, R. D.

    2002-01-01

    Europa's subsurface water ocean may be warm: that is, at the temperature of water's maximum density. This provides a natural explanation of chaos melt-through events and leads to a correct estimate of the age of its surface. Additional information is contained in the original extended abstract.

  13. Europa's Northern Trailing Hemisphere: Lineament Stratigraphic Framework

    NASA Technical Reports Server (NTRS)

    Figueredo, P. H.; Hare, T.; Ricq, E.; Strom, K.; Greeley, R.; Tanaka, K.; Senske, D.

    2004-01-01

    Knowledge of the global distribution of Europan geologic units in time and space is a necessary step for the synthesis of the results of the Galileo mission and in preparation for future exploration (namely, by JIMO) of the satellite. We have initiated the production of the first Global Geological Map of Europa. As a base map, we use the recently published global photomosaic of Europa (U.S.G.S. Map I-2757) and additional Galileo SSI images at their original resolution. The map is being produced entirely on GIS format for analysis and combination with other datasets [1]. One of the main objectives of this project is to establish a global stratigraphic framework for Europa. In the absence of a well-developed cratering record, this goal will be achieved using the satellite s global network of lineaments (ridges, ridge complexes and bands; cf. [2]). Here we present the preliminary stratigraphic framework synthesized from the sequence of lineaments derived for the northern trailing hemisphere of Europa (Figure 1, below), and we discuss its significance and some emerging implications.

  14. Subsurface Exploration Technologies and Strategies for Europa

    NASA Technical Reports Server (NTRS)

    French, L. C.; Anderson, F. S.; Carsey, F. D.; Green, J. R.; Lane, A. L.; Zimmerman, W. F.

    2001-01-01

    The Galileo data from Europa has resulted in the strong suggestion of a large, cold, salty, old subglacial ocean and is of great importance. We have examined technology requirements for subsurface exploration of Europa and determined that scientific access to the hypothesized Europa ocean is a key requirement. By 'scientific access' we intend to direct attention to the fact that several aspects of exploration of a site such as Europa must be addressed at the system level. Specifically needed are a robotic vehicle that can descend through ice, scientific instrumentation that can interrogate the ice near the vehicle (but largely unaffected by its presence), scientific instrumentation for the subglacial ocean, communication for data and control, chemical analysis of the environment of the vehicle in the ice as well as the ocean, and methods for conducting the mission without contamination. We have embarked on a part of this extremely ambitious development sequence by developing the Active Thermal Probe, or Cryobot. Additional information is contained in the original extended abstract.

  15. Evidence for a subsurface ocean on Europa

    USGS Publications Warehouse

    Carr, M.H.; Belton, M.J.S.; Chapman, C.R.; Davies, M.E.; Geissler, P.; Greenberg, R.; McEwen, A.S.; Tufts, B.R.; Greeley, R.; Sullivan, R.; Head, J.W.; Pappalardo, R.T.; Klaasen, K.P.; Johnson, T.V.; Kaufman, J.; Senske, D.; Moore, J.; Neukum, G.; Schubert, G.; Burns, J.A.; Thomas, P.; Veverka, J.

    1998-01-01

    Ground-based spectroscopy of Jupiter's moon Europa, combined with gravity data, suggests that the satellite has an icy crust roughly 150 km thick and a rocky interior. In addition, images obtained by the Voyager spacecraft revealed that Europa's surface is crossed by numerous intersecting ridges and dark bands (called lineae) and is sparsely cratered, indicating that the terrain is probably significantly younger than that of Ganymede and Callisto. It has been suggested that Europa's thin outer ice shell might be separated from the moon's silicate interior by a liquid water layer, delayed or prevented from freezing by tidal heating; in this model, the lineae could be explained by repetitive tidal deformation of the outer ice shell. However, observational confirmation of a subsurface ocean was largely frustrated by the low resolution (>2 km per pixel) of the Voyager images. Here we present high-resolution (54 m per pixel) Galileo spacecraft images of Europa, in which we find evidence for mobile 'icebergs'. The detailed morphology of the terrain strongly supports the presence of liquid water at shallow depths below the surface, either today or at some time in the past. Moreover, lower- resolution observations of much larger regions suggest that the phenomena reported here are widespread.

  16. Europa Tide Inversion from REASON Altimetry

    NASA Astrophysics Data System (ADS)

    Haynes, M.; Schroeder, D. M.; Steinbrügge, G.; Bills, B. G.

    2015-12-01

    Determining the amplitude of Europa's tides is central to understanding its ice shell and subsurface ocean. We assess the accuracy of retrieving the tidal amplitude solely using altimetry profiles produced by the REASON instrument (Radar for Europa Assessment and Sounding: Ocean to Near-surface), selected for the Europa Clipper mission. We investigate retrieval of the first Love number, h2, by inverting the entire set of altimetric ground tracks over the life of the mission. The inversion simultaneously estimates h2, long-wavelength topography, and spacecraft orbit parameters. In its simplest form, the inversion is quite robust: the time and location of the ground track uniquely fixes the phase of the sampled tide, where surface roughness acts as noise to be averaged out. In addition, we make an initial evaluation of altimetric biases that arise from known and hypothesized Europa topography using surface point target simulations. Overall, we find that the altimeter alone is capable of retrieving the first tidal Love number with accuracy sufficient to observationally constrain ice-shell thickness.

  17. Planetary protection for Europa radar sounder antenna

    NASA Astrophysics Data System (ADS)

    Aaron, Kim M.; Moussessian, Alina; Newlin, Laura E.; Willis, Paul B.; Chen, Fei; Harcke, Leif J.; Chapin, Elaine; Jun, Insoo; Gim, Yonggyu; McEachen, Michael; Allen, Scotty; Kirchner, Donald; Blankenship, Donald

    2016-05-01

    The potential for habitability puts stringent requirements on planetary protection for a mission to Europa. A long-wavelength radar sounder with a large antenna is one of the proposed instruments for a future Europa mission. The size and construction of radar sounding antennas make the usual methods of meeting planetary protection requirements challenging. This paper discusses a viable planetary protection scheme for an antenna optimized for Europa radar sounding. The preferred methodology for this antenna is exposure to 100 kGy (10 Mrad) in water of gamma radiation using a Cobalt-60 source for both bulk and surface sterilization and exposure to vapor hydrogen peroxide for surface treatment for possible recontamination due to subsequent handling. For the boom-supported antenna design, selected tests were performed to confirm the suitability of these treatment methods. A portion of a coilable boom residual from an earlier mission was irradiated and its deployment repeatability confirmed with no degradation. Elasticity was measured of several fiberglass samples using a four-point bending test to confirm that there was no degradation due to radiation exposure. Vapor hydrogen peroxide treatment was applied to the silver-coated braid used as the antenna radiating element as it was the material most likely to be susceptible to oxidative attack under the treatment conditions. There was no discernable effect. These tests confirm that the radar sounding antenna for a Europa mission should be able tolerate the proposed sterilization methods.

  18. Europa Missions: Generic Materials Test Methodology

    NASA Technical Reports Server (NTRS)

    Willis, Paul B.

    2006-01-01

    This viewgraph presentation discusses: radiation fundamentals, radiation damage, how radiation dosage is determined, fluence testing approaches, ionization damage exposure, displacement damage exposure, Europa energy "bins", rationale for group flux (energy bins), electron/proton group fluences, electron beam exposure testing, proton sources, reactor exposures, gamma exposures, preliminary exposure findings, testing caveats, preliminary conclusions, internal discharge, and electron dose depth curves.

  19. Project Galileo: completing Europa, preparing for Io

    NASA Technical Reports Server (NTRS)

    Erickson, J. K.; Cox, Z. N.; Paczkowski, B. G.; Sible, R. W.; Theilig, E. E.

    2000-01-01

    Galileo has completed the Europa leg of the Galileo Europa Mission, and is now pumping down the apojove in each succeeding orbit in preparation for the Io phase. Including three encounters earlier in the primary mission, the total of ten close passes by Europa have provided a wealth of interesting and provocative information about this intriguing body. The results presented include new and exciting information about Europa's interactions with Jupiter's magnetosphere, its interior structure, and its tantalizing surface features, which strongly hint at a watery subsurface layer. Additional data concerning Callisto, and its own outlook for a subsurface ocean are also presented. In addition the engineering aspects of operating the spacecraft during the past year are explored, as well as a brief examination of what will be the challenges to prepare for the Io encounters. The steadily increasing radiation dosage that the spacecraft is experiencing is well beyond the original design parameters, and is contributing to a number of spacecraft problems and concerns. The ability of the flight team to analyze and solve these problems, even at the reduced staffing levels of an extended mission, is a testament to their tenacity and loyalty to the mission. The engineering data being generated by these continuing radiation-induced anomalies will prove invaluable to designers of future spacecraft to Jupiter and its satellites. The lessons learned during this arduous process are presented. c 2000 International Astronautical Federation. Published by Elsevier Science Ltd. All rights reserved.

  20. Exploring Europa's Habitability: Science achieved from the Europa Orbiter and Clipper Mission Concepts

    NASA Astrophysics Data System (ADS)

    Senske, D. A.; Prockter, L. M.; Pappalardo, R. T.; Patterson, G. W.; Vance, S.

    2012-12-01

    Europa is a prime candidate in the search for present-day habitable environments in our solar system. Europa is unique among the large icy satellites because it probably has a saltwater ocean today beneath an ice shell that is geodynamically active. The combination of irradiation of its surface and tidal heating of its interior could make Europa a rich source of chemical energy for life. Perhaps most importantly, Europa's ocean is believed to be in direct contact with its rocky mantle, where conditions could be similar to those on Earth's biologically rich sea floor. Hydrothermal zones on Earth's seafloor are known to be rich with life, powered by energy and nutrients that result from reactions between the seawater and the warm rocky ocean floor. Life as we know it depends on three principal "ingredients": 1) a sustained liquid water environment; 2) essential chemical elements that are critical for building life; and 3) a source of energy that could be utilized by life. Europa's habitability requires understanding whether it possesses these three ingredients. NASA has enlisted a study team to consider Europa mission options feasible over the next decade, compatible with NASA's projected planetary science budget and addressing Planetary Decadal Survey priorities. Two Europa mission concepts (Orbiter and multiple flyby—call the "Clipper") are undergoing continued study with the goal to "Explore Europa to investigate its habitability." Each mission would address this goal in complementary ways, with high science value of its own. The Orbiter and Clipper architectures lend themselves to specific types of scientific measurements. The Orbiter concept is tailored to the unique geophysical science that requires being in orbit at Europa. This includes confirming the existence of an ocean and characterizing that ocean through geophysical measurements of Europa's gravitational tides and magnetic induction response. It also includes mapping of the global morphology and

  1. Search for Trace Species at Europa

    NASA Astrophysics Data System (ADS)

    McGrath, Melissa; Sparks, William; Spencer, John

    2015-11-01

    Understanding the present surface composition of Europa provides critical information about its potential habitability. From Earth we currently have very few tools at our disposal to measure Europa’s composition. Two notable exceptions are Keck NIR spectroscopy (cf Brown and Hand 2013) and Hubble Space Telescope UV spectroscopy (cf Cunningham et al. 2015). In March 2015 we obtained 5 orbits of deep UV spectroscopy of Europa using the Cosmic Origins Spectrograph covering wavelength range 1170-1760 Å. The purpose of the observations was to detect trace species in Europa’s exosphere, which is generated by charged particle sputtering of Europa’s water ice surface. The composition of the exosphere therefore provides an indirect measurement of surface composition. Furthermore, if active plumes are present, the composition of the exosphere may also reflect the composition of Europa’s subsurface water reservoir. Of particular interest in the observed wavelength range are multiplets of atomic chlorine, because chlorine is predicted to be a major constituent of Europa’s ocean (Kargel et al. 2000), and Na and K chlorides are expected to be major constituents of the icy shell (Zolotov and Shock 2001; Zolotov and Kargel 2009). The present situation at Europa is analogous to that at Io in the late 1990s, when chlorine ions were first detected in the plasma near Io (Kuppers and Schneider 2000), motivating searches for atomic chlorine and chlorine-bearing species that were subsequently detected in Io’s atmosphere (Lellouch et al. 2003, Feaga et al. 2004). Galileo plasma measurements have detected chlorine ions near Europa (Volwerk et al. 2001), which has motivated the present search for chlorine in Europa’s exosphere. We will present the new COS spectra of Europa and discuss the implications of the trace species that have been detected in these data.

  2. Mapping Europa's Thermophysical Properties from Galileo PPR

    NASA Astrophysics Data System (ADS)

    Rathbun, Julie A.; Rodriguez, N. J.; Spencer, J. R.

    2009-09-01

    The Galileo Photopolarimeter-Radiometer (PPR) instrument mapped thermal infrared radiation from Jupiter and the Galilean satellites. We use the resulting brightness temperatures at a range of local times to map the thermal properties of Europa's surface, namely bolometric albedo and thermal inertia. Ten high-quality PPR observations were identified based on their coverage and lack of noise. We divided the surface of Europa into 10 degree bins and searched the high-quality data for points in each of those bins. We sorted through the bins to find those with observations near noon and at night, as comparison of these times provides the most robust constraint on thermal properties. For each of these bins, we fit a thermal model to determine the thermal inertia and bolometeric albedo of that bin. Our resulting maps of these quantities cover only the subset of the surface where sufficient data was obtained: a band near the anti-Jovian point and a thinner band near 310 W longitude. Allowing for the low resolution of our maps, our thermally-derived albedos appear to correlate with the albedo features observed in the Galileo SSI basemap. The thermal inertia maps provide a unique probe of the cm-scale properties of Europa's surface, and thus constrain surface processes. Knowledge of diurnal temperatures also allows estimation of the detectability of endogenic hot spots. The improved knowledge of Europa's surface temperature distribution provided by these temperature maps and derived thermophysical properties will also aid in the design of thermal instrumentation to search for endogenic activity on future Europa missions.

  3. The europa initiative for esa's cosmic vision: a potential european contribution to nasa's Europa mission

    NASA Astrophysics Data System (ADS)

    Blanc, Michel; Jones, Geraint H.; Prieto-Ballesteros, Olga; Sterken, Veerle J.

    2016-04-01

    The assessment of the habitability of Jupiter's icy moons is considered of high priority in the roadmaps of the main space agencies, including the decadal survey and esa's cosmic vision plan. the voyager and galileo missions indicated that europa and ganymede may meet the requirements of habitability, including deep liquid aqueous reservoirs in their interiors. indeed, they constitute different end-terms of ocean worlds, which deserve further characterization in the next decade. esa and nasa are now both planning to explore these ice moons through exciting and ambitious missions. esa selected in 2012 the juice mission mainly focused on ganymede and the jupiter system, while nasa is currently studying and implementing the europa mission. in 2015, nasa invited esa to provide a junior spacecraft to be carried on board its europa mission, opening a collaboration scheme similar to the very successful cassini-huygens approach. in order to define the best contribution that can be made to nasa's europa mission, a europa initiative has emerged in europe. its objective is to elaborate a community-based strategy for the proposition of the best possible esa contribution(s) to nasa's europa mission, as a candidate for the upcoming selection of esa's 5th medium-class mission . the science returns of the different potential contributions are analysed by six international working groups covering complementary science themes: a) magnetospheric interactions; b) exosphere, including neutrals, dust and plumes; c) geochemistry; d) geology, including expressions of exchanges between layers; e) geophysics, including characterization of liquid water distribution; f) astrobiology. each group is considering different spacecraft options in the contexts of their main scientific merits and limitations, their technical feasibility, and of their interest for the development of esa-nasa collaborations. there are five options under consideration: (1) an augmented payload to the europa mission main

  4. Science and Reconnaissance from the Europa Clipper Mission Concept: Exploring Europa's Habitability

    NASA Astrophysics Data System (ADS)

    Senske, D.; Pappalardo, R. T.; Prockter, L. M.; Paczkowski, B.; Vance, S.; Goldstein, B.; Magner, T. J.; Cooke, B.

    2014-12-01

    Europa is a prime candidate to search for a present-day habitable environment in our solar system. As such, NASA has engaged a Science Definition Team (SDT) to define a strategy to advance our scientific understanding of this icy world with the goal: Explore Europa to investigate its habitability. A mission architecture is defined where a spacecraft in Jupiter orbit would make many close flybys of Europa, concentrating on remote sensing to explore the moon. The spacecraft trajectory would permit ~45 flybys at a variety of latitudes and longitudes, enabling globally distributed regional coverage of Europa's surface. This concept is known as the Europa Clipper. The SDT recommended three science objectives for the Europa Clipper: Ice Shell and Ocean--Characterize the ice shell and any subsurface water, including their heterogeneity, ocean properties, and the nature of surface-ice-ocean exchange; Composition--Understand the habitability of Europa's ocean through composition and chemistry; Geology--Understand the formation of surface features, including sites of recent or current activity, and characterize high science interest localities. The SDT also considered implications of the recent HST detection of plumes at Europa. To feed forward to potential future exploration that could be enabled by a lander, it was deemed that the Clipper should provide the capability to perform reconnaissance. In consultation with NASA Headquarters, the SDT developed a reconnaissance goal: Characterize Scientifically Compelling Sites, and Hazards, for a Potential Future Landed Mission to Europa. This leads to two objectives: Site Safety--Assess the distribution of surface hazards, the load-bearing capacity of the surface, the structure of the subsurface, and the regolith thickness; Science Value--Assess the composition of surface materials, the geologic context of the surface, the potential for geological activity, the proximity of near surface water, and the potential for active

  5. Southeast Asia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Home to beautiful jungles, booming industry, and age-old temples, Southeast Asia has become a confluence of ancient and modern life. This true-color image of mainland Southeast Asia was acquired on November 30, 2001, by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. The body of water in the upper righthand corner of the image is the Gulf of Tonkin. East and southeast of the gulf are the dark green jungles of Vietnam, Laos, and Cambodia. The light brown Mekong River winds its way through the center of the Cambodian jungle and into southern Vietnam. The dark blue patch to the left of the river at the bottom of the image is the Tonle Sap. Literally translated to mean 'Great Lake,' the Tonle Sap is the largest freshwater lake in Southeast Asia. During the rainy season from May to October, the lake will more than double in size growing from its wintertime extent of 3,000 square kilometers to over 7,500 square kilometers. North of the lake, approximately in the center of the image, is a saucer-shaped patch of reddish brown land known as the Khorat Plateau. Situated 90 to 200 meters above sea level in eastern Thailand, the dry plateau is mostly covered with farmland and savanna-type grasses and shrubs. Moving south again, the large body of light blue water at the bottom central portion of the image is the Gulf of Thailand. By switching to the full resolution image (250 meters per pixel) and following the Gulf of Thailand to its northernmost extent, one can see a pinkish beige patch of terrain covered by a faint latticework of fine lines. These are likely to be the network of roads that crisscross Bangkok and its surrounding suburbs and fertile farmland. The narrow strip of land to the east of the Gulf of Thailand is the Malay Peninsula. The body of water to the left of the peninsula is the Gulf of Martaban, which borders Myanmar (Burma). At the far upper lefthand corner of the image, the water has turned light brown from

  6. Inferring human history in East Asia from Y chromosomes

    PubMed Central

    2013-01-01

    East Asia harbors substantial genetic, physical, cultural and linguistic diversity, but the detailed structures and interrelationships of those aspects remain enigmatic. This question has begun to be addressed by a rapid accumulation of molecular anthropological studies of the populations in and around East Asia, especially by Y chromosome studies. The current Y chromosome evidence suggests multiple early migrations of modern humans from Africa via Southeast Asia to East Asia. After the initial settlements, the northward migrations during the Paleolithic Age shaped the genetic structure in East Asia. Subsequently, recent admixtures between Central Asian immigrants and northern East Asians enlarged the genetic divergence between southern and northern East Asia populations. Cultural practices, such as languages, agriculture, military affairs and social prestige, also have impacts on the genetic patterns in East Asia. Furthermore, application of Y chromosome analyses in the family genealogy studies offers successful showcases of the utility of genetics in studying the ancient history. PMID:23731529

  7. A SIMPLE Perspective on Europa's Habitability

    NASA Astrophysics Data System (ADS)

    Schmidt, B. E.

    2014-12-01

    While on the surface, Europa and the Earth may seem very different worlds, below their respective icy crusts, the two share remarkably similar conditions, temperatures, pressures (within a factor of a few) and potentially salinity. Thus the interface between Earth's thick permanent ice shelves and ocean is an important and little explored analog for the physicochemical, and possibly microbial, characteristics of Europa. Here, processes of melt, freeze, and marine ice accretion are controlled by gradients in ice thickness, currents, and ocean temperatures. The details of this process are not well characterized, even on Earth, in particular for the impact these have on the biological potential of these ices. For Europa, such a process may not only provide a habitable niche at ice-ocean interface, but also potentially within the ice shell. In addition, any material formed at the interface may be subject to transport upward through convection or diapirism, potentially delivering ocean-derived materials to the shallow subsurface, participating in an ice "conveyor belt" that will affect the habitability of Europa's ice and ocean alike. In the 2012, 2014 and 2015 austral summer antarctic field seasons, NASA's SIMPLE project (Sub-Ice Marine and PLanetary-analog Ecosystems), has been tasked with characterizing these processes in the McMurdo Ice Shelf, a small ice shelf easily accessible from USAP's McMurdo Station. Using sub-ice vehicles, ice penetrating radar, and other measurements of this unexplored region, the SIMPLE team is building a comprehensive picture of processes at the ice-ocean interface and within the brine-infiltrated ice shelf in order to advance hypotheses for Europa. In addition, the technologies supported by the project are advancing NASA's capabilities to detect processes and properties within ice by ice penetrating radar, and with in situ measurements, that will support Europa Clipper and future landers. The SIMPLE team consists of members from Georgia

  8. The Geology and Astrobiology of Europa (Invited)

    NASA Astrophysics Data System (ADS)

    Chyba, C. F.; Hand, K. P.

    2009-12-01

    Galileo’s discovery of the jovian moons was a crucial step in the process, completed by Newton, that overthrew the Aristotelian dichotomy between the physics of the terrestrial realm and the physics of the heavens. Now, 400 years later, we know of one kind of biology, Earth biology (DNA-protein life) and have glimpses of other possibilities more closely or distantly related (e.g., the RNA world). The galilean satellite Europa is one of the most likely venues in our solar system for presenting us with another example of life, and life likely from an entirely separate origin. Europa therefore gives us a chance to extend our understanding of biology beyond Earth biology to a more generalized biology, providing a biological counterpart to the galilean/newtonian revolution. This possibility is the reason that Europa is one of the highest priorities in solar system exploration. It is a still entirely speculative but credible possibility, because of Europa’s extraordinary geophysics and chemistry. First, radiogenic decay and tidal energy appear sufficient to maintain a subsurface liquid water ocean on Europa that resides between an ice shell and a rocky mantle. Gravity measurements confirm this differentiation, and magnetometer measurements seem to confirm the liquidity of the ocean. Magnetometer measurements further put strong limits on the thickness of the ice shell overlying the ocean and on the salinity of the ocean itself. Because the ocean is covered by kilometers of ice, the enormous free energy of sunlight is rarely available for chemistry or possible biology, but radiolytic chemistry at the surface ice may provide a powerful oxidizing arrow for the ocean that, coupled with deep hydrothermal activity, maintains a supply of electron acceptor and donor pairs that could be used by life. The details of this scenario depend on surface impact gardening and sputtering rates, and on the interaction of the ice shell with the ocean. Current estimates based on cratering

  9. The Europa Explorer - A Fresh Look at Exploring Europa with an RPS-Powered Spacecraft

    NASA Astrophysics Data System (ADS)

    Abelson, Robert D.; Clark, Karia B.

    2007-01-01

    An orbital mission to Europa has been identified as a high priority by the science community for several years. The difficulty of this type of mission, primarily due to the propulsive requirements and Jupiter's trapped radiation, led to many studies which investigated various approaches to meeting the science goals. A flagship-class Europa orbiting mission, which performs a multi-year study of the Jupiter system, can now be envisioned relying on existing technologies, having significantly more capability and returning considerably more science data than previous conventional propulsion mission concepts. This study resulted in several mission concept designs ranging significantly in capability and commensurate cost. The concept discussed herein returns three year's worth of Cassini data (~3 Tbit) in approximately 90 days around Europa. During its 3 month (90 day) Europa Prime Mission, the spacecraft would orbit Europa over 1000 times and provide three orders of magnitude more close (<5000 km altitude) Europa observing time than Galileo. A science group was formed to verify that the science objectives and goals were being adequately met by the mission design concept. The mission concept consists of a single orbiter which would traverse to Jupiter by means of a gravity assist trajectory and reach Jupiter ~6 years after launch, followed by an ~112 year tour of the Galilean satellites before entering Europa orbit. The Europa Prime Mission would be 90 days with high expectations of being operational for upwards of a year. Due to the significant power requirements, tight pointing requirements and intense radiation levels, this mission would be enabled by radioisotope power systems (RPSs). RPSs would be used for all onboard electrical power, with the excess heat used for thermal control of the spacecraft's subsystems. While the mission 31 baselines the use of eight Multi-mission Radioisotope Thermoelectric Generators (MMRTGs), trade studies were also performed to assess

  10. Europa Explorer: A Mission to Explore Europa and Investigate Its Habitability

    NASA Astrophysics Data System (ADS)

    Clark, K. B.; Pappalardo, R. T.; Greeley, R.

    2007-12-01

    Europa is the astrobiological archetype for icy satellite habitability, with a warm, salty, water ocean with plausible chemical energy sources. It is also a geophysical wonderland of interrelated ice shell processes that are intimately related to the ocean and tides, and of complex interactions among its interior, surface, atmosphere, and particles and fields environments. In 2007, NASA commissioned a study of a flagship-class mission to Europa, with the aim of launching as early as 2015. The difficulty of this type of mission, primarily due to the propulsive requirements and Jupiter's trapped radiation, led to many previous studies which investigated various approaches to meeting the science objectives. The Europa Explorer is a mature orbiter concept to explore Europa and investigate its habitability, fulfilling objectives laid out by the National Research Council's Planetary Science Decadal Survey. The mission examines Europa's ocean, ice shell, chemistry, geology, external environment, and neighborhood. With a nominal launch in June 2015, the flight system arrives at Jupiter in 6 years using a Venus- Earth-Earth Gravity Assist trajectory. It would orbit Jupiter for 2 years using gravity assists of the icy Galilean satellites to lower its energy, providing the opportunity for significant Jupiter system science. It would then enter Europa orbit at an altitude of 100-200 km, where it would perform science investigations for 1 year. A campaign- based operations scenario has been developed which permits return of 5.4 Tbits of science data beginning in July 2021, and emphasizing the highest priority Europa science objectives early in the orbital phase of the mission. The baseline mission concept includes 11 instruments that address high-priority investigations while providing the flexibility to respond to discoveries. A less ambitious mission has also been evaluated which has 8 instruments and returns about a third of the data with 6 months of orbital operations at

  11. Africa, Asia, Europe, and Latin America.

    ERIC Educational Resources Information Center

    Loh, Eudora I.

    1991-01-01

    Includes annotations for 19 government publications from 17 countries: Bolivia, Botswana, Burundi, Chile, Costa Rica, Mali, Mexico, Morocco, Mozambique, Netherlands, New Zealand, Nicaragua, Nigeria, Niue, Peru, Rwanda, and the Soviet Union. Topics covered include pornography, poverty, food, and hunger. The effect of library budget pressures on…

  12. First evidence for a Europa plasma torus

    NASA Technical Reports Server (NTRS)

    Intriligator, D. S.; Miller, W. D.

    1982-01-01

    The evidence from the Pioneer 10 plasma analyzer that plasma derived from Europa was present in the Jovian magnetosphere in December 1973 is summarized. Plasma detected between 1900 UT and 2100 UT on December 3, 1973, reveals a number of significant phenomena near the expected position of Europa's L shell. Mass addition to the magnetospheric plasma is indicated by a local increase in density apparently superimposed on the density gradient of Iogenic plasma. This increase in plasma density is unlike any phenomenon observed when the spacecraft is near a lunar L shell. The density shows fluctuations that make possible an estimate of the net outflow speed of magnetospheric ions per Jovian rotation. A radial flow speed in 1973 of 0.37 km/s from the Pioneer data is made, together with an estimate of 1 km/s in 1979 from Voyager 2 data, thus indicating a significant change.

  13. Europa planetary protection for Juno Jupiter Orbiter

    NASA Astrophysics Data System (ADS)

    Bernard, Douglas E.; Abelson, Robert D.; Johannesen, Jennie R.; Lam, Try; McAlpine, William J.; Newlin, Laura E.

    2013-08-01

    NASA's Juno mission launched in 2011 and will explore Jupiter and its near environment starting in 2016. Planetary protection requirements for avoiding the contamination of Europa have been taken into account in the Juno mission design. In particular Juno's polar orbit, which enables scientific investigations of parts of Jupiter's environment never before visited, also greatly assist avoiding close flybys of Europa and the other Galilean satellites. The science mission is designed to conclude with a deorbit burn that disposes of the spacecraft in Jupiter's atmosphere. Compliance with planetary protection requirements is verified through a set of analyses including analysis of initial bioburden, analysis of the effect of bioburden reduction due to the space and Jovian radiation environments, probabilistic risk assessment of successful deorbit, Monte-Carlo orbit propagation, and bioburden reduction in the event of impact with an icy body.

  14. Europa Planetary Protection for Juno Jupiter Orbiter

    NASA Technical Reports Server (NTRS)

    Bernard, Douglas E.; Abelson, Robert D.; Johannesen, Jennie R.; Lam, Try; McAlpine, William J.; Newlin, Laura E.

    2010-01-01

    NASA's Juno mission launched in 2011 and will explore the Jupiter system starting in 2016. Juno's suite of instruments is designed to investigate the atmosphere, gravitational fields, magnetic fields, and auroral regions. Its low perijove polar orbit will allow it to explore portions of the Jovian environment never before visited. While the Juno mission is not orbiting or flying close to Europa or the other Galilean satellites, planetary protection requirements for avoiding the contamination of Europa have been taken into account in the Juno mission design.The science mission is designed to conclude with a deorbit burn that disposes of the spacecraft in Jupiter's atmosphere. Compliance with planetary protection requirements is verified through a set of analyses including analysis of initial bioburden, analysis of the effect of bioburden reduction due to the space and Jovian radiation environments, probabilistic risk assessment of successful deorbit, Monte-Carlo orbit propagation, and bioburden reduction in the event of impact with an icy body.

  15. Liquid water and active resurfacing on Europa

    NASA Technical Reports Server (NTRS)

    Squyres, S. W.; Reynolds, R. T.; Cassen, P. M.; Peale, S. J.

    1983-01-01

    Arguments for recent resurfacing of Europa by H2O from a liquid layer are presented, based on new interpretations of recent spacecraft and earth-based observations and revised theoretical calculations. The heat flow in the core and shell due to tidal forces is discussed, and considerations of viscosity and convection in the interior are found to imply water retention in the outer 60 km or so of the silicates, forming a layer of water/ice many tens of km thick. The outer ice crust is considered to be too thin to support heat transport rates sufficient to freeze the underlying water. Observational evidence for the calculations would consist of an insulating layer of frosts derived from water boiling up between cracks in the surface crust. Evidence for the existence of such a frost layer, including the photometric function of Europa and the deposits of sulfur on the trailing hemisphere, is discussed.

  16. The EJSM Jupiter-Europa Orbiter: Mission Overview

    NASA Astrophysics Data System (ADS)

    Pappalardo, R. T.; Clark, K.; Greeley, R.; Hendrix, A. R.; Tan-Wang, G.; Lock, R.; van Houten, T.; Ludwinski, J.; Petropoulis, A.; Jun, I.; Boldt, J.; Kinnison, J.

    2008-09-01

    Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, Galileo supplied fascinating new insights into that satellite's secrets. The Jupiter Europa Orbiter (JEO) would be the NASA-led portion of the Europa Jupiter System Mission (EJSM), an international mission with orbiters developed by NASA, ESA and possibly JAXA. JEO would address key components of the complete EJSM science objectives and would be designed to function alone or in conjunction with the ESA-led Jupiter Ganymede Orbiter and JAXA-led Jupiter Magnetospheric Orbiter. The JEO mission concept uses a single orbiter flight system which would travel to Jupiter to perform a multi-year study of the Jupiter system and Europa, including 2.5-3 years of Jupiter system science and a comprehensive Europa orbit phase of upt ot a year. This abstract describes the design concept of this mission.

  17. Europa Lander mission and the context of international cooperation

    NASA Astrophysics Data System (ADS)

    Europa Lander Team; Zelenyi, L.; Korablev, O.; Martynov, M.; Popov, G. A.; Blanc, M.; Lebreton, J. P.; Pappalardo, R.; Clark, K.; Fedorova, A.; Akim, E. L.; Simonov, A. A.; Lomakin, I. V.; Sukhanov, A.; Eismont, N.

    2011-08-01

    From 2007 the Russian Academy of Sciences and Roscosmos consider to develop a Europa surface element, in coordination with the Europa Jupiter System Mission (EJSM) international project planned to study the Jupiter system. The main scientific objectives of the Europa Lander are to search for the signatures of possible present and extinct life, in situ studies of the Europa internal structure, the surface and the environment. The mission includes the lander, and the relay orbiter, to be launched by Proton and carried to Jupiter with electric propulsion. The mass of scientific instruments on the lander is ˜50 kg, and its planned lifetime is 60 days. A dedicated international Europa Lander Workshop (ELW) was held in Moscow in February 2009. Following the ELW materials and few recent developments, the paper describes the planned mission, including the science goals, technical design of the mission elements, the ballistic scheme, and the synergy between the Europa Lander and the EJSM.

  18. Natural and False Color Views of Europa

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This image shows two views of the trailing hemisphere of Jupiter's ice-covered satellite, Europa. The left image shows the approximate natural color appearance of Europa. The image on the right is a false-color composite version combining violet, green and infrared images to enhance color differences in the predominantly water-ice crust of Europa. Dark brown areas represent rocky material derived from the interior, implanted by impact, or from a combination of interior and exterior sources. Bright plains in the polar areas (top and bottom) are shown in tones of blue to distinguish possibly coarse-grained ice (dark blue) from fine-grained ice (light blue). Long, dark lines are fractures in the crust, some of which are more than 3,000 kilometers (1,850 miles) long. The bright feature containing a central dark spot in the lower third of the image is a young impact crater some 50 kilometers (31 miles) in diameter. This crater has been provisionally named 'Pwyll' for the Celtic god of the underworld.

    Europa is about 3,160 kilometers (1,950 miles) in diameter, or about the size of Earth's moon. This image was taken on September 7, 1996, at a range of 677,000 kilometers (417,900 miles) by the solid state imaging television camera onboard the Galileo spacecraft during its second orbit around Jupiter. The image was processed by Deutsche Forschungsanstalt fuer Luftund Raumfahrt e.V., Berlin, Germany.

    The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo

  19. Assessment of Alternative Europa Mission Architectures

    NASA Technical Reports Server (NTRS)

    Langmaier, Jerry; Elliott, John; Clark, Karla; Pappalardo, Robert; Reh, Kim; Spilker, Tom

    2008-01-01

    The purpose of this study was to assess the science merit, technical risk and qualitative assessment of relative cost of alternative architectural implementations as applied to a first dedicated mission to Europa. The objective was accomplished through an examination of mission concepts resulting from previous and ongoing studies. Key architectural elements that were considered include moon orbiters, flybys (single flybys like New Horizons and multiple flybys similar to the ongoing Jupiter System Observer study), sample return and in situ landers and penetrators.

  20. Continued evolution of Europa subsurface exploration technologies

    NASA Technical Reports Server (NTRS)

    Carsey, F. D.; Hecht, M. H.; Lane, A. L.; Mogensen, C.; Zimmerman, W.

    2002-01-01

    The Galileo results convincingly indicate that Europa has a deep salty ocean covered by a shell of water ice a few tens of kilometers thick; this physical description gives rise to a host of thoughtful speculation as to the nature of the ocean, its seafloor, and the likelihood of microbial life within it. We argue that this situation points to the high desirability of a series of in-situ missions to examine the ice and, ultimately, the ocean.

  1. Geologic Evidence of Internal Activity on Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This six frame mosaic of Europa's surface shows a variety of interesting geologic features. The prominent 'X' near the center of the mosaic is the junction of two 'triplebands.' Triplebands are seen here to be made up of parallel sets of ridges, and can be traced for over 1,600 kilometers (off the image) across Europa's surface. Directly to the south of the 'X' is a 75 by 100 kilometer (km) area where the icy crust of Europa has been disrupted by activity from below. This activity could be motion in liquid water, convection in warm ice, or some other process. Many icy blocks, some as large as 10 km across, have been rafted from the edges of this zone. Also seen in this mosaic are various pits and domes that range in size from a few kilometers to nearly 20 km across. These geologic features provide evidence of thermal activity below Europa's surface at the time that the features formed.

    These images were obtained by the Solid State Imaging (CCD) system on NASA's Galileo spacecraft during its sixth orbit around Jupiter. North is to the top of the picture, with the sun illuminating the scene from the right. The center of this mosaic is located near 10 degrees north latitude, 271 degrees west longitude. The image, which is about 300 by 300 km across, was acquired at a resolution of 180 meters per picture element.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  2. Compositional Mapping of Europa's Surface with SUDA

    NASA Astrophysics Data System (ADS)

    Kempf, S.; Sternovsky, Z.; Horanyi, M.; Hand, K. P.; Srama, R.; Postberg, F.; Altobelli, N.; Gruen, E.; Gudipati, M. S.; Schmidt, J.; Zolotov, M. Y.; Tucker, S.; Hoxie, V. C.; Kohnert, R.

    2015-12-01

    The Surface Mass Analyzer (SUDA) measures the composition of ballistic dust particles populating the thin exospheres that were detected around each of the Galilean moons. Since these grains are direct samples from the moons' icy surfaces, unique composition data will be obtained that will help to define and constrain the geological activities on and below the moons' surface. SUDA will make a vital contribution to NASA's mission to Europa and provide key answers to its main scientific questions about the surface composition, habitability, the icy crust, and exchange processes with the deeper interior of the Jovian icy moon Europa. SUDA is a time-of- flight, reflectron-type impact mass spectrometer, optimised for a high mass resolution which only weakly depends on the impact location. The small size, low mass and large sensitive area meet the challenging demands of mission to Europa. A full-size prototype SUDA instrument was built in order to demonstrate its performance through calibration experiments at the dust accelerator at NASA's IMPACT institute at Boulder, CO, with a variety of cosmo-chemically relevant dust analogues. The effective mass resolution of m/Δm of 150-300 is achieved for mass range of interest m = 1-150.

  3. U.S. coal outlook in Asia

    SciTech Connect

    Johnson, C.J.

    1997-02-01

    Coal exports from the US to Asia are declining over time as a result of (1) increased competition from coal suppliers within the Asia-Pacific region, (2) changing steel making technologies, (3) decreased emphasis on security of coal supplies, and (4) deregulation of the energy industry--particularly electric utilities. There are no major changes on the horizon that are likely to alter the role of the US as a modest coal supplier to the Asia-Pacific region. The downward trend in US coal exports to Asia is expected to continue over the 1997--2010 period. But economic and policy changes underway in Asia are likely to result in periodic coal shortages, lasting a few months to a year, and short term increased export opportunities for US coal. US coal exports to Asia are projected to fluctuate within the following ranges over the 2000--2010 period: 10--17 million tons in total exports, 6--12 million tons in thermal coal exports, and 4--9 million tons in coking coal exports. The most important role for US coal, from the perspective of Asian coal importing countries, is to ensure a major alternative source of coal supplies that can be turned to in the event of unforeseen disruptions in coal supplies from the Asia-Pacific region or South Africa. However, the willingness of consumers to pay a premium to ensure US export capacity is declining, with increased emphasis on obtaining the lowest cost coal supplies.

  4. Enhanced electromagnetic sounding of Europa's ocean using CubeSats

    NASA Astrophysics Data System (ADS)

    Crary, Frank; Holmes, Justin; Malaspina, David; Mason, James; Ranquist, Drake; Schiller, Quintin; Sturner, Andrew; Kohnert, Rick

    2015-04-01

    Diagnosing the properties of Europa's ocean is a key objective of the planned Europa Clipper mission. Magnetic field measurements reveal the inductive signatures of the ocean, but also contain perturbations from the magnetospheric interaction with Europa. Determining the properties of the ocean using this technique requires separating the induced field from that of the magnetospheric interaction. One solution is to use magnetometer-bearing CubeSats to make simultaneous flybys along trajectories separated from that of the Europa Clipper. We describe a concept for such nanosatellites and how they could greatly enhance the precision of induced magnetic field ocean soundings.

  5. A highly integrated payload suite for Europa

    NASA Astrophysics Data System (ADS)

    Bentley, M.; Kraft, S.; Steiger, R.; Varlet, F.; Voigt, D.; Falkner, P.; Peacock, A.

    The four Galilean moons have always held a public and scientific fascination due to their diverse and dynamic nature. Amongst the moons, Europa holds a special place for its potential liquid water ocean, beneath its icy crust. This prospect of water places Europa on a par with Mars in terms of its viability for harbouring life. The first hints of Europa's icy surface came from early telescopic observations, which noted an unusually high albedo. Ground based spectroscopy then demonstrated absorption features of relatively pure water ice. Imagery from Pioneer, Voyager, and more recently Galileo confirm this, with the kilometre scale resolution of Galileo showing what appear to be ice flows. The lack of cratering, pointing to a geologically recent surface, furthermore suggests that liquid water could well exist today. The Galileo Europa Mission (GEM) provided much more extensive data during its 8 close orbits, including limited areas of extremely high resolution imaging (6 m), and radio science that confirmed the differentiated nature of Europa. However, many fundamental questions remain that can best be answered by a dedicated orbiter. For example: - Does a liquid water ocean exist? What it its extent vertically and laterally? - What is the composition of the crust? - What are the geological processes operating? The importance of these most basic questions have inspired mission proposals from all of the major space agencies. In Europe, ESA have performed a study into a mission called the "Jupiter Minisat Explorer" in order to identify the key technologies that would have to be developed [1]. The key technological challenges are caused by the harsh Jovian radiation environment, the lack of solar energy available and the thermal problems of such a cold environment. Last, but not least, a payload must be designed that satisfies these requirements and is both low power and low mass. All of these factors dictate the use of a Highly Integrated Payload Suite (HIPS). Such a

  6. Trajectory Design for the Europa Clipper Mission Concept

    NASA Technical Reports Server (NTRS)

    Buffington, Brent

    2014-01-01

    Europa is one of the most scientifically intriguing targets in planetary science due to its potential suitability for extant life. As such, NASA has funded the California Institute of Technology Jet Propulsion Laboratory and the Johns Hopkins University Applied Physics Laboratory to jointly determine and develop the best mission concept to explore Europa in the near future. The result of nearly 4 years of work--the Europa Clipper mission concept--is a multiple Europa flyby mission that could efficiently execute a number of high caliber science investigations to meet Europa science priorities specified in the 2011 NRC Decadal Survey, and is capable of providing reconnaissance data to maximize the probability of both a safe landing and access to surface material of high scientific value for a future Europa lander. This paper will focus on the major enabling component for this mission concept--the trajectory. A representative trajectory, referred to as 13F7-A21, would obtain global-regional coverage of Europa via a complex network of 45 flybys over the course of 3.5 years while also mitigating the effects of the harsh Jovian radiation environment. In addition, 5 Ganymede and 9 Callisto flybys would be used to manipulate the trajectory relative to Europa. The tour would reach a maximum Jovicentric inclination of 20.1 deg. have a deterministic (Delta)V of 164 m/s (post periapsis raise maneuver), and a total ionizing dose of 2.8 Mrad (Si).

  7. Reconstructing Plate Motions on Europa with GPlates

    NASA Astrophysics Data System (ADS)

    Cutler, B. B.; Collins, G. C.; Prockter, L. M.; Patterson, G.; Kattenhorn, S. A.; Rhoden, A.; Cooper, C. M.

    2015-12-01

    Observations of past plate tectonic - like motions in Europa's icy lithosphere have been reported in previous studies. Quantifying the nature, age, and amount of plate motion is important for geophysical models of Europa's ice shell and for astrobiology, since subsumed pates could drive the flow of nutrients into the subsurface ocean. We have used GPlates software (Williams et al., GSA Today 2012) and a mosaic of regional-resolution Galileo SSI data from orbits E11, E15, E17, and E19 to make interactive reconstructions of both the Northern Falga region (60N, 220W) and the Castalia Macula region (0N, 225W). The advantage of this method is that plate motions are calculated on a sphere, while still maintaining the original Galileo image pieces in their proper geographic locations. Previous work on the Castalia Macula region (Patterson et al. J.Struct.Geol. 2006) and the adjacent Phaidra Linea region (Patterson and Ernst, LPSC 2011) found offsets along spreading boundaries, and then calculated the best fit finite rotations to close those offsets. Though this method is mathematically rigorous and gives a statistical goodness of fit, it is not easy to test multiple hypotheses for candidate piercing points or divisions of candidate plate boundaries. Through the interactive environment, we found that we could better account for observed offsets in this region by breaking it into 32 different plates. Patterson and Ernst broke the Phaidra region into 6 plates which exhibited nonrigid behavior, where our study breaks it into 16 rigid plates. The Northern Falga Regio area is interesting due to the potential for large amounts of subsumption of Europa's icy crust in this location. The previous reconstruction (Kattenhorn and Prockter, Nat.Geosci. 2014) was based on planar geometry, and we have replicated these results using a spherically-based reconstruction. We will present the plate maps and reconstructions for both of these regions, along with the best fit rotation poles.

  8. Europa's near-surface O2 atmosphere

    NASA Astrophysics Data System (ADS)

    Cassidy, T. A.; Johnson, R. E.

    The surfaces of 'airless' bodies in our solar system are covered by porous regoliths; granular, porous surfaces generated by micrometeor impact. Europa's tenuous neutral atmosphere (composed primarily of O2 ) is generated by UV and plasma irradiation of, and sublimation from, this regolith. Hubble Space Telescope (HST) observation by McGrath et al. (2004) suggested that Europa's O2 atmosphere is spatially nonuniform. Previous simulations (e.g. Shematovich et al., Icarus, 2005), which assumed that O2 could only be lost by pickup and escape, found that a spatially nonuniform source could not produce the morphology suggested by the HST observations. It is shown here that a nonuniform surface/O2 interaction, treated here as surface reactivity, results in a spatially nonuniform O2 atmosphere with the highest column density above the regions of lowest reactivity. We can reproduce this nonuniformity even with very slight reactivity. Slight reactivity makes a difference because of the many interactions an O2 molecule experiences with the surface during its lifetime; for which there are two reasons: (1) the many returns to the surface experienced by a thermal molecule; desorption followed by ballistic arc followed by desorption and so on. (2) the regolith structure: each time an O2 molecule returns to the surface it interacts not just once, but many times due to the porous nature of the regolith (Cassidy and Johnson, Icarus, 2005). Thus, in addition to the atmosphere above the surface, there is a substantial amount of gas in the porous regolith. This "regolith atmosphere" may resolve a question surrounding CO2 condensed on Europa's surface.

  9. Europa Surface Radiation Environment for Lander Assessment

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Sturner, Steven J.

    2006-01-01

    The Jovian magnetospheric particle environment at Europa's surface is critical to assessment of landed astrobiological experiments in three respects: (1) the landing site must be chosen for the best prospects for detectable organic or inorganic signs of Life, e.g. regions of freshly emergent flows from the subsurface; (2) lander systems must reach the surface through the Jovian magnetospheric environment and operate long enough on the surface to return useful data; (3) lander instrumentation must be capable of detecting signs of life in the context of the local environmental radiation and associated chemistry. The Galileo, Voyager, and Pioneer missions have provided a wealth of data on energetic particle intensities throughout the Jovian magnetosphere including from many flybys of Europa. cumulative radiation dosages for spacecraft enroute to Europa can be well characterized, but knowledge of the surface radiation environment is very limited. Energetic electrons should primarily impact the trailing hemisphere with decreasing intensity towards the center of the leading hemisphere and are the most significant radiation component down to meter depths in the surface regolith due to secondary interactions. Observed surface distribution for sulfates is suggestive of electron irradiation but may have alternative interpretations. Having much-larger magnetic gyroradii than electrons, energetic protons and heavier ions irradiate more of the global surface. The particular orientations of electron, proton, and ion gyromotion would project into corresponding directional (e.g., east-west) anisotropies of particle flu into the surface. Particular topographic features at the landing site may therefore offer shielding from part of the incident radiation.

  10. Calculations of electric currents in Europa

    NASA Technical Reports Server (NTRS)

    Colburn, D. S.; Reynolds, R. T.

    1986-01-01

    Electrical currents should flow in the Galilean satellite, Europa, because it is located in Jupiter's corotating magnetosphere. The possible magnitudes of these currents are calculated by assuming that Europa is a differentiated body consisting of an outer H2O layer and a silicate core. Two types of models are considered here: one in which the water is completely frozen and a second in which there is an intermediate liquid layer. For the transverse electric mode (eddy currents), the calculated current density in a liquid layer is approximately 10 to the -5/Am. For the transverse magnetic mode (unipolar generator), the calculated current density in the liquid is severely constrained by the ice layer to a range of only 10 to the -10 to -11th power/ Am, for a total H2O thickness of 100 km, provided that neither layer is less than 4 km thick. The current density is less for a completely frozen H2O layer. If transient cracks were to appear in the ice layer, thereby exposing liquid, the calculated current density could rise to a range of 10 to the -6 to 10 to the -5/Am, depending on layer thicknesses, which would require an exposed area of 10 to the -9 to 10 to the -8 of the Europa surface. The corresponding total current of 2.3x10 to the 5th power A could in 1 yr. electrolyze 7x10 to the 5th power kg of water (and more if the cells were in series), and thereby store up to 10 the 8th power J of energy, but it is not clear how electrolysis can take place in the absence of suitable electrodes. Electrical heating would be significant only if the ice-layer thickness were on the order of 1 m, such as might occur if an exposed liquid surface were to freeze over; the heating under this condition could hinder the thickening of the ice layer.

  11. Numerical Simulations of Europa Hydrothermal Plumes

    NASA Astrophysics Data System (ADS)

    Goodman, J. C.; Lenferink, E.

    2009-12-01

    The liquid water interiors of Europa and other icy moons of the outer solar system are likely to be driven by geothermal heating from the sea floor, leading to the development of buoyant hydrothermal plumes. These plumes potentially control icy surface geomorphology, and are of interest to astrobiologists. We have performed a series of simulations of these plumes using the MITGCM. We assume in this experiment that Europa's ocean is deep (of order 100 km) and unstratified, and that plume buoyancy is controlled by temperature, not composition. A series of experiments was performed to explore a limited region of parameter space, with ocean depth H ranging from 50 to 100 km deep, source heat flux Q between 1 and 10 GW, and values of the Coriolis parameter f between 30% and 90% of the Europa average value. As predicted by earlier work, the plumes in our simulations form narrow cylindrical chimneys (a few km across) under the influence of the Coriolis effect. These plumes broaden over time until they become baroclinically unstable, breaking up into cone-shaped eddies when they become 20-35 km in diameter; the shed eddies are of a similar size. Large-scale currents in the region of the plume range between 1.5 and 5 cm/s; temperature anomalies in the plume far from the seafloor are tiny, varying between 30 and 160 microkelvin. Variations in plume size, shape, speed, and temperature are in excellent agreement with previous laboratory tank experiments, and in rough agreement with theoretical predictions. Plume dynamics and geometry are controlled by a "natural Rossby number" which depends strongly on depth H and Coriolis parameter f, but only weakly on source heat flux Q. However, some specific theoretical predictions are not borne out by these simulations. The time elapsed between startup of the source and the beginning of eddy-shedding is much less variable than predicted; also, the plume temperature varies with ocean depth H when our theory says it should not. Both of

  12. Jupiter Europa Orbiter Architecture Definition Process

    NASA Technical Reports Server (NTRS)

    Rasmussen, Robert; Shishko, Robert

    2011-01-01

    The proposed Jupiter Europa Orbiter mission, planned for launch in 2020, is using a new architectural process and framework tool to drive its model-based systems engineering effort. The process focuses on getting the architecture right before writing requirements and developing a point design. A new architecture framework tool provides for the structured entry and retrieval of architecture artifacts based on an emerging architecture meta-model. This paper describes the relationships among these artifacts and how they are used in the systems engineering effort. Some early lessons learned are discussed.

  13. Seismic detectability of meteorite impacts on Europa

    NASA Astrophysics Data System (ADS)

    Tsuji, Daisuke; Teanby, Nicholas

    2016-04-01

    Europa, the second of Jupiter's Galilean satellites, has an icy outer shell, beneath which there is probably liquid water in contact with a rocky core. Europa, may thus provide an example of a sub-surface habitable environment so is an attractive object for future lander missions. In fact, the Jupiter Icy Moon Explorer (JUICE) mission has been selected for the L1 launch slot of ESA's Cosmic Vision science programme with the aim of launching in 2022 to explore Jupiter and its potentially habitable icy moons. One of the best ways to probe icy moon interiors in any future mission will be with a seismic investigation. Previously, the Apollo seismic experiment, installed by astronauts, enhanced our knowledge of the lunar interior. For a recent mission, NASA's 2016 InSight Mars lander aims to obtain seismic data and will deploy a seismometer directly onto Mars' surface. Motivated by these works, in this study we show how many meteorite impacts will be detected using a single seismic station on Europa, which will be useful for planning the next generation of outer solar system missions. To this end, we derive: (1) the current small impact flux on Europa from Jupiter impact rate models; (2) a crater diameter versus impactor energy scaling relation for ice by merging previous experiments and simulations; (3) scaling relations for seismic signals as a function of distance from an impact site for a given crater size based on analogue explosive data obtained on Earth's icy surfaces. Finally, resultant amplitudes are compared to the noise level of a likely seismic instrument (based on the NASA InSight mission seismometers) and the number of detectable impacts are estimated. As a result, 0.5-3.0 local/regional small impacts (i.e., direct P-waves through the ice crust) are expected to be detected per year, while global-scale impact events (i.e., PKP-waves refracted through the mantle) are rare and unlikely to be detected by a short duration mission. We note that our results are

  14. Europa Explorer - An Exceptional Mission Using Existing Technology

    NASA Technical Reports Server (NTRS)

    Clark, Karla B.

    2007-01-01

    A mission to Europa has been identified as a high priority by the science community for several years. The difficulty of an orbital mission, primarily due to the propulsive requirements and Jupiter's trapped radiation, led to many studies which investigated various approaches to meeting the science goals. The Europa Orbiter Mission studied in the late 1990's only met the most fundamental science objectives. The science objectives have evolved with the discoveries from the Galileo mission. JPL studied one concept, Europa Explorer, for a Europa orbiting mission which could meet a much expanded set of science objectives. A study science group was formed to verify that the science objectives and goals were being adequately met by the resulting mission design concept. The Europa Explorer design emerged primarily from two key self-imposed constraints: 1) meet the full set of identified nonlander science objectives and 2) use only existing technology.

  15. A new concept for the exploration of Europa.

    PubMed

    Rampelotto, Pabulo Henrique

    2012-06-01

    The Europa Jupiter System Mission (EJSM) is the major Outer Planet Flagship Mission in preparation by NASA. Although well designed, the current EJSM concept may present problematic issues as a Flagship Mission for a long-term exploration program that will occur over the course of decades. For this reason, the present work reviews the current EJSM concept and presents a new strategy for the exploration of Europa. In this concept, the EJSM is reorganized to comprise three independent missions focused on Europa. The missions are split according to scientific goals, which together will give a complete understanding of the potential habitability of Europa, including in situ life's signal measurements. With this alternative strategy, a complete exploration of Europa would be possible in the next decades, even within a politically and economically constrained environment. PMID:22794296

  16. Europa's differentiated internal structure: inferences from four Galileo encounters.

    PubMed

    Anderson, J D; Schubert, G; Jacobson, R A; Lau, E L; Moore, W B; Sjogren, W L

    1998-09-25

    Radio Doppler data from four encounters of the Galileo spacecraft with the jovian moon Europa have been used to refine models of Europa's interior. Europa is most likely differentiated into a metallic core surrounded by a rock mantle and a water ice-liquid outer shell, but the data cannot eliminate the possibility of a uniform mixture of dense silicate and metal beneath the water ice-liquid shell. The size of a metallic core is uncertain because of its unknown composition, but it could be as large as about 50 percent of Europa's radius. The thickness of Europa's outer shell of water ice-liquid must lie in the range of about 80 to 170 kilometers. PMID:9748159

  17. Life Beneath Glacial Ice - Earth(!) Mars(?) Europa(?)

    NASA Technical Reports Server (NTRS)

    Allen, Carlton C.; Grasby, Stephen E.; Longazo, Teresa G.; Lisle, John T.; Beauchamp, Benoit

    2002-01-01

    We are investigating a set of cold springs that deposit sulfur and carbonate minerals on the surface of a Canadian arctic glacier. The spring waters and mineral deposits contain microorganisms, as well as clear evidence that biological processes mediate subglacial chemistry, mineralogy, and isotope fractionation . The formation of native sulphur and associated deposits are related to bacterially mediated reduction and oxidation of sulphur below the glacier. A non-volcanic, topography driven geothermal system, harboring a microbiological community, operates in an extremely cold environment and discharges through solid ice. Microbial life can thus exist in isolated geothermal refuges despite long-term subfreezing surface conditions. Earth history includes several periods of essentially total glaciation. lee in the near subsurface of Mars may have discharged liquid water in the recent past Cracks in the ice crust of Europa have apparently allowed the release of water to the surface. Chemolithotrophic bacteria, such as those in the Canadian springs, could have survived beneath the ice of "Snowball Earth", and life forms with similar characteristics might exist beneath the ice of Mars or Europa. Discharges of water from such refuges may have brought to the surface living microbes, as well as longlasting chemical, mineralogical, and isotopic indications of subsurface life.

  18. Antarctic analog for dilational bands on Europa

    NASA Astrophysics Data System (ADS)

    Hurford, T. A.; Brunt, K. M.

    2014-09-01

    Europa's surface shows signs of extension, which is revealed as lithospheric dilation expressed along ridges, dilational bands and ridged bands. Ridges, the most common tectonic feature on Europa, comprise a central crack flanked by two raised banks a few hundred meters high on each side. Together these three classes may represent a continuum of formation. In Tufts' Dilational Model ridge formation is dominated by daily tidal cycling of a crack, which can be superimposed with regional secular dilation. The two sources of dilation can combine to form the various band morphologies observed. New GPS data along a rift on the Ross Ice Shelf, Antarctica is a suitable Earth analog to test the framework of Tufts' Dilational Model. As predicted by Tufts' Dilational Model, tensile failures in the Ross Ice Shelf exhibit secular dilation, upon which a tidal signal can be seen. From this analog we conclude that Tufts' Dilational Model for Europan ridges and bands may be credible and that the secular dilation is most likely from a regional source and not tidally driven.

  19. Antarctic Analog for Dilational Bands on Europa

    NASA Technical Reports Server (NTRS)

    Hurford, T. A.; Brunt, K. M.

    2014-01-01

    Europa's surface shows signs of extension, which is revealed as lithospheric dilation expressed along ridges, dilational bands and ridged bands. Ridges, the most common tectonic feature on Europa, comprise a central crack flanked by two raised banks a few hundred meters high on each side. Together these three classes may represent a continuum of formation. In Tufts' Dilational Model ridge formation is dominated by daily tidal cycling of a crack, which can be superimposed with regional secular dilation. The two sources of dilation can combine to form the various band morphologies observed. New GPS data along a rift on the Ross Ice Shelf, Antarctica is a suitable Earth analog to test the framework of Tufts' Dilational Model. As predicted by Tufts' Dilational Model, tensile failures in the Ross Ice Shelf exhibit secular dilation, upon which a tidal signal can be seen. From this analog we conclude that Tufts' Dilational Model for Europan ridges and bands may be credible and that the secular dilation is most likely from a regional source and not tidally driven.

  20. Europa Clipper Mission Concept Preliminary Planetary Protection Approach

    NASA Astrophysics Data System (ADS)

    Jones, Melissa; Schubert, Wayne; Newlin, Laura; Cooper, Moogega; Chen, Fei; Kazarians, Gayane; Ellyin, Raymond; Vaishampayan, Parag; Crum, Ray

    2016-07-01

    The science objectives of the proposed Europa Clipper mission consist of remotely characterizing any water within and beneath Europa's ice shell, investigating the chemistry of the surface and ocean, and evaluating geological processes that may permit Europa's ocean to possess the chemical energy necessary for life. The selected payload supporting the science objectives includes: Plasma Instrument for Magnetic Sounding (PIMS), Interior Characterization of Europa using Magnetometry (ICEMAG), Mapping Imaging Spectrometer for Europa (MISE), Europa Imaging System (EIS), Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON), Europa Thermal Emission Imaging System (E-THEMIS), MAss SPectrometer for Planetary EXploration/Europa (MASPEX), Ultraviolet Spectrograph/Europa (UVS), and SUrface DUst Mass Analyzer (SUDA). Launch is currently baselined as 2022. Pending the yet to be selected launch vehicle, the spacecraft would either arrive to the Jovian system on a direct trajectory in 2025 or an Earth-Venus-Earth-Earth gravity assist interplanetary trajectory arriving in 2030. The operational concept consists of multiple low-altitude flybys of Europa to obtain globally distributed regional coverage of the Europan surface. According to COSPAR Policy, it is currently anticipated that the Europa Clipper mission would be classified as a Category III mission. That is, the mission is to a body "of significant interest relative to the process of chemical evolution and/or the origin of life or for which scientific opinion provides a significant chance of contamination which could jeopardize a future biological experiment." Therefore, the expected driving planetary protection requirement for the mission is that the probability of inadvertent contamination of an ocean or other liquid water body shall be less than 1x10-4 per mission. This requirement applies until final disposition of the spacecraft, however in practice, would only apply until the spacecraft is

  1. The Europa Imaging System (EIS): Investigating Europa's geology, ice shell, and current activity

    NASA Astrophysics Data System (ADS)

    Turtle, Elizabeth; Thomas, Nicolas; Fletcher, Leigh; Hayes, Alexander; Ernst, Carolyn; Collins, Geoffrey; Hansen, Candice; Kirk, Randolph L.; Nimmo, Francis; McEwen, Alfred; Hurford, Terry; Barr Mlinar, Amy; Quick, Lynnae; Patterson, Wes; Soderblom, Jason

    2016-07-01

    NASA's Europa Mission, planned for launch in 2022, will perform more than 40 flybys of Europa with altitudes at closest approach as low as 25 km. The instrument payload includes the Europa Imaging System (EIS), a camera suite designed to transform our understanding of Europa through global decameter-scale coverage, topographic and color mapping, and unprecedented sub- meter-scale imaging. EIS combines narrow-angle and wide-angle cameras to address these science goals: • Constrain the formation processes of surface features by characterizing endogenic geologic structures, surface units, global cross-cutting relationships, and relationships to Europa's subsurface structure and potential near-surface water. • Search for evidence of recent or current activity, including potential plumes. • Characterize the ice shell by constraining its thickness and correlating surface features with subsurface structures detected by ice penetrating radar. • Characterize scientifically compelling landing sites and hazards by determining the nature of the surface at scales relevant to a potential lander. EIS Narrow-angle Camera (NAC): The NAC, with a 2.3°° x 1.2°° field of view (FOV) and a 10-μμrad instantaneous FOV (IFOV), achieves 0.5-m pixel scale over a 2-km-wide swath from 50-km altitude. A 2-axis gimbal enables independent targeting, allowing very high-resolution stereo imaging to generate digital topographic models (DTMs) with 4-m spatial scale and 0.5-m vertical precision over the 2-km swath from 50-km altitude. The gimbal also makes near-global (>95%) mapping of Europa possible at ≤50-m pixel scale, as well as regional stereo imaging. The NAC will also perform high-phase-angle observations to search for potential plumes. EIS Wide-angle Camera (WAC): The WAC has a 48°° x 24°° FOV, with a 218-μμrad IFOV, and is designed to acquire pushbroom stereo swaths along flyby ground-tracks. From an altitude of 50 km, the WAC achieves 11-m pixel scale over a 44-km

  2. Malaria successes and challenges in Asia.

    PubMed

    Bhatia, Rajesh; Rastogi, Rakesh Mani; Ortega, Leonard

    2013-12-01

    Asia ranks second to Africa in terms of malaria burden. In 19 countries of Asia, malaria is endemic and 2.31 billion people or 62% of the total population in these countries are at risk of malaria. In 2010, WHO estimated around 34.8 million cases and 45,600 deaths due to malaria in Asia. In 2011, 2.7 million cases and > 2000 deaths were reported. India, Indonesia, Myanmar and Pakistan are responsible for >85% of the reported cases (confirmed) and deaths in Asia. In last 10 yr, due to availability of donor's fund specially from Global fund, significant progress has been made by the countries in Asia in scaling-up malaria control interventions which were instrumental in reducing malaria morbidity and mortality significantly. There is a large heterogeneity in malaria epidemiology in Asia. As a result, the success in malaria control/elimination is also diverse. As compared to the data of the year 2000, out of 19 malaria endemic countries, 12 countries were able to reduce malaria incidence (microscopically confirmed cases only) by 75%. Two countries, namely Bangladesh and Malaysia are projected to reach 75% reduction by 2015 while India is projected to reach 50-75% only by 2015. The trend could not be assessed in four countries, namely Indonesia, Myanmar, Pakistan and Timor-Leste due to insufficient consistent data. Numerous key challenges need to be addressed to sustain the gains and eliminate malaria in most parts of Asia. Some of these are to control the spread of resistance in Plasmodium falciparum to artemisinin, control of outdoor transmission, control of vivax malaria and ensuring universal coverage of key interventions. Asia has the potential to influence the malaria epidemiology all over the world as well as to support the global efforts in controlling and eliminating malaria through production of quality-assured ACTs, RDTs and long-lasting insecticidal nets. PMID:24499845

  3. Jovian Tour Design for Orbiter and Lander Missions to Europa

    NASA Technical Reports Server (NTRS)

    Campagnola, Stefano; Buffington, Brent B.; Petropoulos, Anastassios E.

    2013-01-01

    Europa is one of the most interesting targets for solar system exploration, as its ocean of liquid water could harbor life. Following the recommendation of the Planetary Decadal Survey, NASA commissioned a study for a flyby mission, an orbiter mission, and a lander mission. This paper presents the moon tours for the lander and orbiter concepts. The total delta v and radiation dose would be reduced by exploiting multi-body dynamics and avoiding phasing loops in the Ganymede-to- Europa transfer. Tour 11-O3, 12-L1 and 12-L4 are presented in details and their performaces compared to other tours from previous Europa mission studies.

  4. Modelling Europa's interaction with Jupiter's magnetosphere: Influence of plumes in Europa's atmosphere on the plasma environment

    NASA Astrophysics Data System (ADS)

    Bloecker, A.; Saur, J.; Roth, L.

    2015-12-01

    We study the influence of plumes in Europa's atmosphere on the interaction with Jupiter's magnetosphere and the plasma environment. We apply a three-dimensional magnetohydrodynamic (MHD) model, which includes plasma production and loss due to electron impact ionization and dissociative recombination, and electromagnetic induction in a subsurface water ocean.The model considers the magnetospheric and ionospheric electrons separately. We show that an atmospherical inhomogeneity, such as a plume, affects the plasma interaction in the way that a pronounced north-south asymmetry in the near and the Alfvénic far field develops. Furthermore, a "small Alfvén winglet" within Europa's Alfvén wing forms. We also investigate if such signatures of atmospherical inhomogeneities are visible in magnetic field measurements of the Galileo magnetometer. In addition to our MHD model we apply an analytical approach based on the model by Saur et al. (2007) for our studies. We compare the model results with the observed magnetic field data from three flybys of Europa that occurred during the Alfvén wing crossing.

  5. Exploring Europa with an RPS-Powered Spacecraft Results of the Europa Explorer Mission Concept Study

    NASA Technical Reports Server (NTRS)

    Abelson, Robert Dean

    2006-01-01

    This viewgraph presentation focuses on the results of the more recent and detailed Europa Explorer (EE) study. Based on the Europa Geophysical Explorer (EGE) the EE Study was more detailed and reached a modified design point, it re-affirmed all the conclusions reached during the EGE Study. The presentation reviews some of the important considerations of the study, including the trajectory design with earth gravity assists, the radiation considerations, the desired instruments for studying Europa, the total mass available, a conceptual illustration of the spacecraft. The attitude, propulsion and thermal control issues are also addressed. The data communications issues are reviewed. The expectations from the mission are summarized in the conclusion. These include a 90 day operational period, that is likely to continue for over a year; that EE would produce 1000 more observations than the Galileo mission; that EE would carry over 200 kg of instrumentation (including shielding); that EE would return over 21 Gigabits of data per Earth day; there would be about 340kg of unused mass, which could be used for more instrumentation, or a lander; and that this would be designed with currently available technology.

  6. Tidal response of Europa's subsurface ocean

    NASA Astrophysics Data System (ADS)

    Karatekin, Özgür; Comblen, Richard; Toubeau, Jonathan; Deleersnijder, Eric; van Hoolst, Tim; Dehant, Veronique

    2010-05-01

    Observations of Cassini and Galileo spacecrafts suggest the presence of subsurface global water oceans under the icy shells of several satellites of Jupiter and Saturn. Previous studies have shown that in the presence of subsurface oceans, time-variable tides cause large periodic surface displacements and that tidal dissipation in the icy shell becomes a major energy source that can affect long-term orbital evolution. However, in most studies so far, the dynamics of these satellite oceans have been neglected. In the present study, we investigate the tidal response of the subsurface ocean of Europa to a time-varying potential. Two-dimensional nonlinear shallow water equations are solved on a sphere by means of a finite element code. The resulting ocean tidal flow velocities and surface displacements will be presented.

  7. Amino acid synthesis in Europa's subsurface environment

    NASA Astrophysics Data System (ADS)

    Abbas, Sam H.; Schulze-Makuch, Dirk

    2008-10-01

    It has been suggested that Europa's subsurface environment may provide a haven for prebiotic evolution and the development of exotic biotic systems. The detection of hydrogen peroxide, sulfuric acid, water, hydrates and related species on the surface, coupled with observed mobility of icebergs, suggests the presence of a substantial subsurface liquid reservoir that actively exchanges materials with the surface environment. The atmospheric, surface and subsurface environments are described with their known chemistry. Three synthetic schemes using hydrogen peroxide, sulfuric acid and hydrocyanic acid leading to the production of larger biologically important molecules such as amino acids are described. Metabolic pathways based on properties of the subsurface ocean environment are detailed. Tidal heating, osmotic gradients, chemical cycling, as well as hydrothermal vents, provide energy and materials that may support a course of prebiotic evolution leading to the development or sustenance of simple biotic systems. Putative organisms may employ metabolic pathways based on chemical oxidation reduction cycles occurring in the putative subsurface ocean environment.

  8. Radar properties of Europa, Ganymede, and Callisto

    NASA Technical Reports Server (NTRS)

    Ostro, S. J.

    1982-01-01

    The radar properties of Europa, Ganymede, and Callisto are summarized and present understanding of these properties is documented. The radar techniques are described, observational results reviewed, and salient aspects of the radar data set discussed. Theoretical interpretation of the satellites' anomalous radar properties is addressed, including aspects such as external scattering and double reflection from hemispherical craters, the random-facet model, total internal reflection, multiple total internal reflection, the high radar geometric albedos, the tenous upper layer, the two-component regolith, and compositional effects. It is concluded that multiple total internal reflection from randomly oriented subsurface facets can explain the anomalous circular polarization inversion in the radar echoes from the three satellites. Several refinements of the Goldstein-Green (1980) scattering model are suggested.

  9. Europa Uomo: the European Prostate Cancer Coalition.

    PubMed

    Hudson, Tom; Denis, Louis J

    2007-01-01

    Europa Uomo is a patient-led, non-governmental association (NGO), launched formally in Milan in 2004 with a legal base in Antwerp. As a coalition of prostate cancer patient groups with representation in 18 European countries, the NGO focusses on awareness, early detection, optimal treatment, multi-professional care and, above all, quality of life and patient advocacy. In the majority of European countries prostate cancer is the most commonly diagnosed cancer affecting men beyond middle age. The incidence and substantial mortality rises with age, peaking in the seventh decade. Standards of diagnosis and treatment vary across Europe and attitudes differ. Information about the early detection and awareness of prostate cancer available to the public leaves much to be desired. Since 2002, involved individuals, patient support groups, patients, family members, physicians, urologists, oncologists and nurses joined in the formation of an independent, international, non-profit association of patient-led prostate cancer support groups from European countries known as Europa Uomo, the European Prostate Cancer Coalition. This Coalition was legally established as an NGO in June 2004 in Milan with the headquarters and secretariat in Antwerp, Belgium. Its membership represents 18 countries by the national or regional groups listed in Table 16.1 with their respective contact persons. The coalition is led by a steering committee under the control of the annual general assembly. The steering committee members and their co-ordinates are listed in Table 16.2. Scientific advice is given by a scientific committee chaired by Prof. H. Van Poppel as the liaison officer with the European Association of Urology (EAU). The support for EAU guidelines appears on the Web site and will be linked to all members in their own language (www.cancerworld.org/europauomo). The goals and activities of Europa Uomo have been condensed in a series of slides at the request of the Eurocan+Plus collaboration to

  10. Europa - The prospects for an ocean

    NASA Technical Reports Server (NTRS)

    Reynolds, R. T.; Mckay, C. P.; Kasting, J. F.; Squires, S. W.

    1988-01-01

    Tidal dissipation in the satellites of a giant planet may provide sufficient heating to maintain a liquid water ocean below a thin ice layer. In the solar system, Europa, one of the Galilean satellites of Jupiter, may have such an ocean. Both theoretical calculations and certain observations support its existence, although proof is lacking. The putative ocean would probably have temperatures, pressures, and chemistry conducive to biologic activity. However, the environment would be severely energy limited. Possible energy sources include transient transmission of sunlight through fractures in the ice and hydrothermal activity on the ocean floor. While temporary conditions could exist that are within the range of adaptation of certain terrestrial organisms, origin of life under such conditions seems unlikely. In other solar systems, however, larger satellites with more significant heat flow could provide environments that are stable over an order of aeons and in which life could perhaps evolve.

  11. Europa's Thermal Surface From Galileo PPR

    NASA Astrophysics Data System (ADS)

    Rodriguez, Nathaniel; Rathbun, J.; Spencer, J.

    2009-01-01

    Europa, one of the four Galilean moons of Jupiter, may harbor a subsurface ocean beneath its icy crust. We use the thermal data gathered from the Galileo spacecraft's PPR instrument to search for endogenic activity. Evidence of endogenic activity would provide direct support for a subsurface-ocean. We are modeling variations in temperature over the course of a day and then fitting these models to the PPR data. The two key variables that affect surface temperature are bolometric albedo and thermal inertia. We are determining these variables for each point on the surface, which will allow us to create a global model of exogenic activity due to sunlight. This information will allow us to analyze the threshold where endogenic activity becomes great enough to be detectable in the PPR data.

  12. Analytical model of Europa's O2 exosphere

    NASA Astrophysics Data System (ADS)

    Milillo, Anna; Plainaki, Christina; Orsini, Stefano; De Angelis, Elisabetta; Mangano, Valeria; Massetti, Stefano; Mura, Alessandro; Rispoli, Rosanna; Colasanti, Luca

    2015-04-01

    The origin of the exosphere of Europa is its water ice surface. The existing exosphere models, assuming either a collisionless environment (simple Monte Carlo techniques) or a kinetic approach (Direct Monte Carlo Method) both predict that the major constituent of the exosphere is molecular oxygen. Specifically, O2 is generated at the surface through radiolysis and chemical interactions of the water dissociation products. The non-escaping O2 molecules circulate around the moon impacting the surface several times, due to their long lifetime and due to their non- sticking, suffering thermalization to the surface temperature after each impact. In fact, the HST observations of the O emission lines have manifested the presence of an asymmetric atomic Oxygen envelope, evidencing the possible existence of a thin asymmetric molecular Oxygen atmosphere. The existing Monte Carlo models are not easily applicable as input of simulations devoted to the study of the plasma interactions with the moon. On the other hand, the simple exponential density profiles cannot well depict the higher temperature/higher altitudes component originating by radiolysis. On the contrary, it would be important to have a suitable and user-friendly model to use as a tool. This study presents an analytical 3D model that is able to describe the molecular Oxygen exosphere by reproducing the asymmetries due to two configurations among Europa, Jupiter and the Sun, that is illumination at leading and at trailing side. This model is obtained by a non-linear fit procedure of the EGEON Monte Carlo model to a Chamberlain density profile. Different parameters of the model are able to describe various exosphere properties thus allowing a detailed investigation of the exospheric characteristics.

  13. Impact Driven Chemistry on Europa's Surface

    NASA Astrophysics Data System (ADS)

    Khare, B. N.; NNa Mvondo, D.; Borucki, J. G.; Cruikshank, D. P.; Belisle, W. A.; Wilhite, P.; McKay, C. P.

    2005-08-01

    A new energy source for organic synthesis on simulated Europan surfaces, electrical discharge, light emission, and magnetic phenomena from impacts into the ice, has been studied [Borucki et al. J. Geophys. Res. 107 (E11) 5114 (2002)]. Part of the impactor's kinetic energy is converted into electrical potential. The mechanical disruption causes the release of energy as light, heat, and electrical and magnetic fields as secondary emissions that synthesizes complex organic material named tholin [Sagan and Khare, Nature 277, 102 (1979)] in the area of impact craters. The morphology of the impact craters indicates that tholin is the result of outflow from the fracture zone. Large pool of liquid water may exist for thousands of years as suggested for Titan [Thompson and Sagan, Eur. Space Agency Spec. Publ., ESA-SP, 338, 167 (1992)] and may also apply to Europa potentially driving prebiotic chemistry due to energy pumped in from the secondary emissions. We have detected 8.8 ppm of H2O2 from impact of a 1/4" iron bullet at 5.3 km/s over water ice at ca. -100 C. H2O2 has been detected on the surface of Europa [Carlson et al., Science 283, 2062 (1999)]. Further confirmation by Raman Scattering at 874.5 cm-1 and IR absorbance at 2854 cm-1 is continuing. Since the impactor is limited in the number of experiments we can run, other experiments used a laser induced plasma (LIP) to shock ice mixed with ammonium sulphate and methanol. We detected CH4, CO, N2O, C2H6, CH3CN, CH3COCH3, HCOOCH3 (methyl formate), and traces of HCN. LIP on a mixture of water and methanol ice produced CH4, CO, HCHO, ethanol, formic acid methylester, propanol, acetone, dimethoxyme, and possibly ethanone-1phenyl or other phenyl group. NH3 and methanol could be delivered on impact of comets while sulfur expelled from Io.

  14. A closer look at Chaos on Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This mosaic of the Conamara Chaos region on Jupiter's moon, Europa, clearly indicates relatively recent resurfacing of Europa's surface. Irregularly shaped blocks of water ice were formed by the break up and movement of the existing crust. The blocks were shifted, rotated, and even tipped and partially submerged within a mobile material that was either liquid water, warm mobile ice, or an ice and water slush. The presence of young fractures cutting through this region indicates that the surface froze again into solid, brittle ice.

    The background image in this picture was taken during Galileo's sixth orbit of Jupiter in February, 1997. Five very high resolution images which were taken during the spacecraft's twelfth orbit in December, 1997 provide an even closer look at some of the details. This mosaic shows some of the high resolution data inset into the context of this tumultuous region.

    North is to the top of the picture, and the sun illuminates the scene from the east (right). The picture, centered at 9 degrees north latitude and 274 degrees west longitude, covers an area approximately 35 by 50 kilometers (20 by 30 miles). The finest details visible in the very high resolution insets are about 20 meters (22 yards) across, and in the background image, 100 meters (110 yards) across. The insets were taken on December 16, 1997, at ranges as close as 880 kilometers (550 miles) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  15. Flow-like Features On Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image shows features on Jupiter's moon Europa that may be 'flows' from ice volcanoes. It was taken by the Galileo spacecraft solid state imaging (CCD) system during its seventh orbit around Jupiter. North is to the top of the image. The sun illuminates the scene from the left, showing features with shapes similar to lava flows on Earth. Two such features can be seen in the northwest corner of the image. The southern feature appears to have flowed over a ridge along its western edge. Scientists use these types of relationships to determine which feature formed first. In this case, the ridge probably formed before the flow-like feature that covers it.

    The image, centered at 22.6 degrees north latitude and 106.7 degrees west longitude, covers an area of 180 by 215 kilometers (112 by 134 miles). The smallest distinguishable features in the image are about 1.1 kilometers (0.7 miles) across. This image was obtained on April 28, 1997, when Galileo was 27,590 kilometers (16,830 miles) from Europa.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  16. Zika Virus Outside Africa

    PubMed Central

    2009-01-01

    Zika virus (ZIKV) is a flavivirus related to yellow fever, dengue, West Nile, and Japanese encephalitis viruses. In 2007 ZIKV caused an outbreak of relatively mild disease characterized by rash, arthralgia, and conjunctivitis on Yap Island in the southwestern Pacific Ocean. This was the first time that ZIKV was detected outside of Africa and Asia. The history, transmission dynamics, virology, and clinical manifestations of ZIKV disease are discussed, along with the possibility for diagnostic confusion between ZIKV illness and dengue.The emergence of ZIKV outside of its previously known geographic range should prompt awareness of the potential for ZIKV to spread to other Pacific islands and the Americas. PMID:19788800

  17. Solar-Powered Europa Orbiter Design Study (2007)

    NASA Technical Reports Server (NTRS)

    Elliott, John; Langmaier, Jerry; Pappalardo, Robert; Strange, Nathan; Spilker, Tom; Lock, Rob; Reh, Kim

    2008-01-01

    The feasibility of implementing a solar-powered mission around Europa has been evaluated periodically over the last decade. Most recently, an assessment was performed as part of the 2006 Europa Explorer (EE) Study, which evaluated the practicality of implementing that mission design with large solar arrays instead of radioisotope power systems (RPS). This previous study went into some depth in considering the issues related to the use of solar arrays in the Europa orbit illumination and radiation environment. The study concluded that an all-solar option was impractical to meet the science objectives as defined in that study by the science team. This conclusion resulted from the prohibitive mass, packaging and articulation issues associated with the very large (approx.300 sq m) solar arrays required to accommodate frequent eclipse periods associated with the particular Europa orbit used.

  18. Detectability of Potentially Entrained Microorganisms at the Surface of Europa

    NASA Technical Reports Server (NTRS)

    Dalton, J. B.

    2002-01-01

    New spectral measurements of bacteria taken at cryogenic temperatures provide insights on the surface composition of Europa as well as the detectability of microbes on the surface. Additional information is contained in the original extended abstract.

  19. Linking Europa's plume activity to tides, tectonics, and liquid water

    NASA Astrophysics Data System (ADS)

    Rhoden, Alyssa Rose; Hurford, Terry A.; Roth, Lorenz; Retherford, Kurt

    2015-06-01

    Much of the geologic activity preserved on Europa's icy surface has been attributed to tidal deformation, mainly due to Europa's eccentric orbit. Although the surface is geologically young (30-80 Myr), there is little information as to whether tidally-driven surface processes are ongoing. However, a recent detection of water vapor near Europa's south pole suggests that it may be geologically active. Initial observations indicated that Europa's plume eruptions are time-variable and may be linked to its tidal cycle. Saturn's moon, Enceladus, which shares many similar traits with Europa, displays tidally-modulated plume eruptions, which bolstered this interpretation. However, additional observations of Europa at the same time in its orbit failed to yield a plume detection, casting doubt on the tidal control hypothesis. The purpose of this study is to analyze the timing of plume eruptions within the context of Europa's tidal cycle to determine whether such a link exists and examine the inferred similarities and differences between plume activity on Europa and Enceladus. To do this, we determine the locations and orientations of hypothetical tidally-driven fractures that best match the temporal variability of the plumes observed at Europa. Specifically, we identify model faults that are in tension at the time in Europa's orbit when a plume was detected and in compression at times when the plume was not detected. We find that tidal stress driven solely by eccentricity is incompatible with the observations unless additional mechanisms are controlling the eruption timing or restricting the longevity of the plumes. The addition of obliquity tides, and corresponding precession of the spin pole, can generate a number of model faults that are consistent with the pattern of plume detections. The locations and orientations of these hypothetical source fractures are robust across a broad range of precession rates and spin pole directions. Analysis of the stress variations across

  20. Orbiter, Flyby and Lander Mission Concepts for Investigating Europa's Habitability

    NASA Astrophysics Data System (ADS)

    Prockter, L. M.

    2012-04-01

    Coauthors: R. T. Pappalardo (1), F. Bagenal (2), A. C. Barr (3), B. G. Bills (1), D. L. Blaney (1), D. D. Blankenship (4), W. Brinckerhoff (5), J. E. P. Connerney (5), K. Hand (1), T. Hoehler (6), W. Kurth (7), M. McGrath (8), M. Mellon (9), J. M. Moore (6), D. A. Senske (1), E. Shock (10), D. E. Smith (11), T. Gavin (1), G. Garner (1), T. Magner (12), B. C. Cooke (1), R. Crum (1), V. Mallder (12), L. Adams (12), K. Klaasen (1), G. W. Patterson (12), and S. D. Vance (1); 1: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA; 2: University of Colorado, Boulder, CO, USA; 3: Brown University, Providence, RI, USA; 4: University of Texas Institute for Geophysics, Austin, TX, USA; 5: NASA Goddard Space Flight Center, Greenbelt, MD, USA; 6: NASA Ames Research Center, Mountain View, CA, USA; 7: University of Iowa, Iowa City, IA, USA; 8: NASA Marshall Space Flight Center, Huntsville, AL, USA; 9: Southwest Research Institute, Boulder, CO, USA; 10: Arizona State University, Tempe, AZ, USA; 11: Massachusetts Institute of Technology, Cambridge, MA, USA; 12: Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA. Introduction: Assessment of Europa's habitability requires understanding whether the satellite possesses the three "ingredients" for life: water, chemistry, and energy. The National Research Council's Planetary Decadal Survey [1] placed an extremely high priority on Europa science but noted that the budget profile for the Jupiter Europa Orbiter (JEO) mission concept [2] is incompatible with NASA's projected planetary science budget. Thus, in April 2011, NASA enlisted a small Europa Science Definition Team (ESDT) to consider Europa mission options that might be more feasible over the next decade from a programmatic perspective. The ESDT has studied three Europa mission concepts: a Europa orbiter, a Europa multiple-flyby mission, and a Europa lander. These share an overarching goal: Explore Europa to investigate its habitability

  1. Plasma IMS Composition Measurements for Europa and Ganymede

    NASA Technical Reports Server (NTRS)

    Sittler, E.; Cooper, J.; Hartle, R.; Lipatov, A.; Mahaffy, P.; Paterson, W.; Paschalidis, N.; Coplan, M.; Cassidy, T.

    2010-01-01

    NASA and ESA are planning the joint Europa Jupiter System Mission (EJSM) to the Jupiter system with specific emphasis to Europa and Ganymede, respectively. The Japanese Space Agency is also planning an orbiter mission to explore Jupiter's magnetosphere and the Galilean satellites. For NASA's Jupiter Europa Orbiter (JEO) we are developing the 3D Ion Mass Spectrometer (IMS) with two main goals which can also be applied to the other Galilean moons, 1) measure the plasma interaction between Europa and Jupiter's magnetosphere and 2) infer the 4n surface composition to trace elemental [1] and significant isotopic levels. The first goal supports the magnetometer (MAG) measurements, primarily directed at detection of Europa's sub-surface ocean, while the second gives information about transfer of material between the Galilean moons, and between the moon surfaces and subsurface layers putatively including oceans. The measurement of the interactions for all the Galilean moons can be used to trace the in situ ion measurements of pickup ions back to either Europa's or Ganymede's surface from the respectively orbiting spacecraft. The IMS instrument, being developed under NASA's Astrobiology Instrument Development Program, would maximally achieve plasma measurement requirements for JEO and EJSM while moving forward our knowledge of Jupiter system composition and source processes to far higher levels than previously envisaged.

  2. Dive Europa: a search-for-life initiative.

    PubMed

    Naganuma, T; Uematsu, H

    1998-06-01

    Liquid water, underwater volcanoes and possibly life forms have been suggested to be present beneath the estimated 10 km-thick ice shell of Europa the Jovian satellite J2. Europa's possible ocean is estimated to be 100-200km deep. Despite the great depth of the Europa's ocean, hydrostatic pressure at the seafloor would be 130-260 MPa, corresponding to 13-26 km depth of a theoretical Earth's ocean. The hydrostatic pressure is not beyond the edge of existing deep-sea technology. Here we propose exploration of Europa's deep-sea by the use of current technologies, taking a symbolic example of a deep submergence vehicle Shinkai 6500 which dives to a depth of 6.5 km deep (50 km depth of Europa's ocean). Shinkai 6500 is embarkable in the payload bay of the Space Shuttles in terms of size and weight for the transportation to a Low Earth Orbit (LEO). Secondary boost is needed for interplanetary flight from the LEO. On-orbit assembly of the secondary booster is a technological challenge. The International Space Station (ISS) and ISS-related technologies will facilitate the secondary boost. Also, ice shell drilling is a challenge and is needed before the dive into Europa's ocean. These challenges should be overcome during a certain leading time for matured experience in the ISS operation. PMID:11541880

  3. West Africa

    Atmospheric Science Data Center

    2013-04-16

    ... article title:  Hazy and Dusty Skies over Western Africa     View Larger Image ... of agricultural fires that were burning throughout western Africa during December and early January, and was likely to have been ...

  4. Southern Africa

    Atmospheric Science Data Center

    2013-04-16

    article title:  Southern Africa     View larger JPEG image ... These Multi-angle Imaging SpectroRadiometer (MISR) images of Africa were acquired on August 25, 2000, during Terra orbit 3655. The left ... of smoke plumes and haze. The southern tip of South Africa is at the bottom of the image, and Zambia is at the top. Distinctive ...

  5. Impact Features on Europa: Results of the Galileo Europa Mission (GEM)

    NASA Astrophysics Data System (ADS)

    Moore, J. M.; Asphaug, E.; Morrison, D.; Sullivan, R. J.; Chapman, C. R.; Greeley, R.; Klemaszewski, J. E.; Kadel, S.; Chuang, F.; Moreau, J.; Williams, K. K.; Geissler, P. E.; McEwen, A. S.; Turtle, E. A.; Phillips, C. B.; Tufts, B. R.; Head, J. W.; Pappalardo, R. T.; Collins, G. C.; Neukum, G.; Wagner, R.; Klaasen, K. P.; Breneman, H. H.; McGee, K. P.; Senske, D. A.; Granahan, J.; Belton, M. J. S.; Galileo SSI Team

    1998-09-01

    The Galileo Orbiter, during the GEM phase of this mission, has examined a number of impact features on Europa at considerably better resolution and coverage than was possible from either Voyager or during the Galileo nominal mission. The new data allow us to describe the morphology and infer the geology of the largest impact features on Europa, which are probes into the crust. The GEM observations allow us to construct a suite of primary impact features on Europa; a comprehensive "family" portrait and ordering (by size on one axis and morphologic variations within a given size bin along the other). We have also made detailed description of individual impact features including topography (from stereo), crater-related materials deposits, cross-cutting relations, and material-related color variations. We observe two basic types of large impact features: (1) "classic" impact craters that grossly resemble well-preserved lunar craters of similar size but are more topographically subdued (e.g., Pwyll); and (2) very flat circular features that lack the basic topographic structures of impact craters such as raised rims, a central depression, or central peaks, and which largely owe their identification as impact features to the field of secondary craters radially sprayed about them (e.g., Callanish). One of our preliminary conclusions are that Callanish and Tyre display non-"classic" impact features morphologies and a series of large concentric structural rings cutting impact-feature-related materials. Impact simulations suggest that Callanish and Tyre would not be produced by impact into a solid ice target, but may be explained by impact into an ice layer 10 to 15 km thick overlying a low viscosity material such as water.

  6. Understanding the Variability of Europa's Interaction with the Jovian Magnetosphere

    NASA Astrophysics Data System (ADS)

    Khurana, Krishan; Jia, Xianzhe; Paranicas, Chris; Cassidy, Timothy; Hansen, Kenneth

    2014-05-01

    Field and plasma observations from the vicinity of Europa by the Galileo spacecraft show that Europa's response to the corotating field and plasma impinging on it is binary in nature. Galileo successfully encountered Europa 10 times during its mission. During nine of these flybys, the interaction between Europa and Jupiter was observed to be fairly modest. The modeling of magnetic data from these flybys shows that the interaction currents were in the range of 0.5 MA and the plasma addition to the corotating flow was between 2 - 8 kg/s. However, during one of the flybys, namely E12, the field and plasma perturbations were observed to be extremely large. During this flyby, the magnetic field was observed to almost double in strength from its nominal value of 450 nT. The plasma density in the environment was also extremely high during this flyby (exceeding 800 particles/cm-3 compared to the nominal values of 50-100 particles/cm3 expected near Europa's orbit). The energetic ion fluxes on the other hand were seen to drop significantly in count presumably from ion losses and cooling in Europa's environment. In order to understand the two interaction states of Europa observed so far, we have now developed quantitative 3-D MHD models of plasma interactions of Europa with Jupiter's magnetosphere. In these models we include the effects of plasma pick-up and plasma interaction with a realistic exosphere as well as the contribution of the electromagnetic induction. We will present results of these quantitative models and show that the plasma interaction is strongest when Europa is located at the center of Jupiter's current sheet. We find that plasma mass loading rates are extremely variable over time. We will investigate various mechanisms by which such variability in mass-loading could be produced including episodically enhanced sputtering from trapped gaseous molecules in ice and enhanced plasma interaction with a vent(s) generated dense exosphere. The new model will aid

  7. Topography within Europa's Mannann'an crater

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This three dimensional effect is created by superimposing images of Jupiter's icy moon, Europa, which were taken from slightly different perspectives. When viewed through red (left eye) and blue (right eye) filters, this product, a stereo anaglyph, shows variations in height of surface features.

    This view shows the rim and interior of the impact crater Mannann'an, on Jupiter's moon Europa. The stereo image reveals the rim of the crater which appears as a tall ridge near the left edge of the image, as well as and numerous small hills on the bottom of the crater. One of the most striking features is the large pit surrounded by circular cracks on the right side of the image, with dark radiating fractures in its center.

    The right (blue) image is a high resolution image (20 meters per picture element) taken through a clear filter. The left (red) image is composed of lower resolution (80 meters per picture element) color images taken through violet, green, and near-infrared filters and averaged to approximate an unfiltered view.

    North is to the top of the picture and the sun illuminates the scene from the east (right). The image, centered at 3 degrees north latitude and 120 degrees west longitude, covers an area approximately 18 by 4 kilometers (11 by 2.5 miles). The finest details that can be discerned in this picture are about 40 meters (44 yards) across. The images were taken on March 29th, 1998 at 13 hours, 17 minutes, 29 seconds Universal Time at a range of 1934 kilometers by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for

  8. Tírez lake as a terrestrial analog of Europa.

    PubMed

    Prieto-Ballesteros, Olga; Rodríguez, Nuria; Kargel, Jeffrey S; Kessler, Carola González; Amils, Ricardo; Remolar, David Fernández

    2003-01-01

    Tírez Lake (La Mancha, central Spain) is proposed as a terrestrial analogue of Europa's ocean. The proposal is based on the comparison of the hydrogeochemistry of Tírez Lake with the geochemical features of the alteration mineralogy of meteoritic precursors and with Galileo's Near Infrared Mapping Spectrometer data on Europa's surface. To validate the astrobiological potential of Tírez Lake as an analog of Europa, different hydrogeochemical, mineral, and microbial analyses were performed. Experimental and theoretical modeling helped to understand the crystallization pathways that may occur in Europa's crust. Calculations about the oxidation state of the hypothetical Europan ocean were estimated to support the sulfate-rich neutral liquid model as the origin of Europa's observed hydrated minerals and to facilitate their comparison with Tírez's hydrogeochemistry. Hydrogeochemical and mineralogical analyses showed that Tírez waters corresponded to Mg-Na-SO(4)-Cl brines with epsomite, hexahydrite, and halite as end members. A preliminary microbial ecology characterization identified two different microbial domains: a photosynthetically sustained community represented by planktonic/benthonic forms and microbial mat communities, and a subsurficial anaerobic realm in which chemolithotrophy predominates. Fluorescence in situ hybridization has been used to characterize the prokaryotic diversity of the system. The subsurficial community seemed to be dominated by sulfate-reducing bacteria and methanogens. Frozen Tírez brines were analyzed by Fourier-transform infrared techniques providing spectra similar to those reported previously using pure components and to the Galileo spectral data. Calorimetric measurements of Tírez brines showed pathways and phase metastability for magnesium sulfate and sodium chloride crystallization that may aid in understanding the processes involved in the formation of Europa's icy crust. The use of fluorescence hybridization techniques for

  9. A Search for Signs of Life and Habitability on Europa

    NASA Technical Reports Server (NTRS)

    Fonda, Mark (Technical Monitor); McKay, Christoper P.; Eicken, H.; Neuer, S.; Sogin, M.; Waite, H.; Warmflash, D.

    2003-01-01

    Europa is a key target in the search for life beyond the Earth because of consistent evidence that below the icy surface there is liquid water. Future missions to Europa could confirm the presence and nature of the ocean and determine the thickness of the ice layer. Confirming the presence of an ocean and determining the habitability of Europa are key astrobiology science objectives. Nevertheless, the highest priority objective for astrobiology will be a search for life. How could a search for life be accomplished on a near-term mission given the thick ice cover? One answer may lie in the surface materials. If Europa has an ocean, and if that ocean contains life, and if water from the ocean is carried up to the surface, then signs of life may be contained in organic material on the surface. Organics that derive from biological processes (dead organisms) are distinct from organics derived from non-biological processes in several aspects. First, biology is selective and specific in its use of molecules. For example, Earth life uses 20 left-handed amino acids. Second, biology can leave characteristic isotopic patterns. Third, biology often produces large complex molecules in high concentrations, for example lipids. Organic material that has been on the surface of Europa for long periods of time would be reprocessed by the strong radiation field probably erasing any signature of biological origin. Evidence of life in the ocean may be found on the surface of Europa if regions of the surface contained relatively recent material carried up from the ocean through cracks in the icy lithosphere. But organic material that has been on the surface of Europa for long periods of time would be reprocessed by the strong radiation field probably erasing any signature of biological origin. Thus, the detailed analysis required may not be possible via remote sensing but direct sampling of the material below the radiation processed upper meter is probably required.

  10. Elektronische Citizen Cards in Deutschland und Europa

    NASA Astrophysics Data System (ADS)

    Kowalski, Bernd

    Meine sehr geehrten Damen und Herren, der Bedarf an elektronischen Identitäten entsteht durch die wachsende Mobilität der Gesellschaft bei einem gleichzeitig steigenden Bedarf an Onlinepräsenz. Diese elektronischen Identitäten machen natürlich auch vor den staatlichen Ausweisen nicht halt, wie zum Beispiel dem Reisepass, aber auch dem Personalausweis und weiteren Ausweisdokumenten. Wobei es bei den staatlich herausgegebenen oder kontrollierten Ausweisen immer um zwei verschiedene Dinge geht: Einmal um die hoheitliche Funktion, wie zum Beispiel beim Reisepass. Hier geht es zum Beispiel darum, in einem Europa mit gefallenen Grenzen und bei freiem Reiseverkehr für alle Personen, die in diesem Raum wohnen, insbesondere auch im Schengener Raum, die Möglichkeit zu schaffen, auch künftig noch Personenkontrollen durchzuführen. Auch der Reiseverkehr über die europäischen Grenzen hinaus ist insofern ein Problem, da die Identitätenprüfung an den Grenzkontrollen immer schwieriger wird. Deswegen braucht man an dieser Stelle Möglichkeiten, um eine Personenüberprüfung durchzuführen, um feststellen zu können, dass diese Person auch zum Dokument gehört.

  11. DSMC simulation of Europa water vapor plumes

    NASA Astrophysics Data System (ADS)

    Berg, J. J.; Goldstein, D. B.; Varghese, P. L.; Trafton, L. M.

    2016-10-01

    A computational investigation of the physics of water vapor plumes on Europa was performed with a focus on characteristics relevant to observation and spacecraft mission operations. The direct simulation Monte Carlo (DSMC) method was used to model the plume expansion assuming a supersonic vent source. The structure of the plume was determined, including the number density, temperature, and velocity fields. The possibility of ice grain growth above the vent was considered and deemed probable for large (diameter > ∼20 m) vents at certain Mach numbers. Additionally, preexisting grains of three diameters (0.1, 1, 50 μm) were included and their trajectories examined. A preliminary study of photodissociation of H2O into OH and H was performed to demonstrate the behavior of daughter species. A set of vent parameters was evaluated including Mach number (Mach 2, 3, 5), reduced temperature as a proxy for flow energy loss to the region surrounding the vent, and mass flow rate. Plume behavior was relatively insensitive to these factors, with the notable exception of mass flow rate. With an assumed mass flow rate of ∼1000 kg/s, a canopy shock occurred and a maximum integrated line of sight column density of ∼1020 H2O molecules/m2 was calculated, comparing favorably with observation (Roth et al., 2014a).

  12. Europa Ice Cliffs-High Resolution

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This view of the Conamara Chaos region on Jupiter's moon Europa shows cliffs along the edges of high-standing ice plates. The washboard texture of the older terrain has been broken into plates which are separated by material with a jumbled texture. The cliffs themselves are rough and broadly scalloped, and smooth debris shed from the cliff faces is piled along the base. For scale, the height of the cliffs and size of the scalloped indentations are comparable to the famous cliff face of Mount Rushmore in South Dakota.

    This image was taken on December 16, 1997 at a range of 900 kilometers (540 miles) by the solid state imaging system (camera) on NASA's Galileo spacecraft. North is to the top right of the picture, and the sun illuminates the surface from the east. This image, centered at approximately 8 degrees north latitude and 273 degrees west longitude, covers an area approximately 1.5 kilometers by 4 kilometers (0.9 miles by 2.4 miles). The resolution is 9 meters (30 feet) per picture element.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  13. ESP in Southeast Asia.

    ERIC Educational Resources Information Center

    Crooks, Tony, Ed.

    Seven conference papers discuss English language training and political development in Asia, including language project design and evaluation, counterparting, sustainability, appropriate technology, and languages and the politics of development. Papers included are: "Linguistic and Cultural Considerations of Writing ELT Texts for Use in Asia"…

  14. AED in Asia

    ERIC Educational Resources Information Center

    Academy for Educational Development, 2004

    2004-01-01

    Founded in 1961, the Academy for Educational Development (AED) is an independent, nonprofit, charitable organization that operates development programs in the United States and throughout the world. This directory presents an overview of AED endeavors in Asia. AED's work in Asia has centered on institution-building, taking advantage of its…

  15. Europa and Callisto under the watchful gaze of Jupiter

    NASA Technical Reports Server (NTRS)

    2000-01-01

    One moment in an ancient, orbital dance is caught in this color picture taken by NASA's Cassini spacecraft on Dec. 7, 2000, just as two of Jupiter's four major moons, Europa and Callisto, were nearly perfectly aligned with each other and the center of the planet.

    The distances are deceiving. Europa, seen against Jupiter, is 600,000 kilometers (370,000 miles) above the planet's cloud tops. Callisto, at lower left, is nearly three times that distance from the cloud tops. Europa is a bit smaller than Earth's Moon and has one of the brightest surfaces in the solar system. Callisto is 50 percent bigger -- roughly the size of Saturn's largest satellite, Titan -- and three times darker than Europa. Its brightness had to be enhanced in this picture, relative Europa's and Jupiter's, in order for Callisto to be seen in this image.

    Europa and Callisto have had very different geologic histories but share some surprising similarities, such as surfaces rich in ice. Callisto has apparently not undergone major internal compositional stratification, but Europa's interior has differentiated into a rocky core and an outer layer of nearly pure ice. Callisto's ancient surface is completely covered by large impact craters: The brightest features seen on Callisto in this image were discovered by the Voyager spacecraft in 1979 to be bright craters, like those on our Moon. In contrast, Europa's young surface is covered by a wild tapestry of ridges, chaotic terrain and only a handful of large craters.

    Recent data from the magnetometer carried by the Galileo spacecraft, which has been in orbit around Jupiter since 1995, indicate the presence of conducting fluid, most likely salty water, inside both worlds.

    Scientists are eager to discover whether the surface of Saturn's Titan resembles that of Callisto or Europa, or whether it is entirely different when Cassini finally reaches its destination in 2004.

    Cassini is a cooperative project of NASA, the European Space Agency and

  16. The State of the Plasma Sheet and Atmosphere at Europa

    NASA Astrophysics Data System (ADS)

    Shemansky, D. E.; Yung, Y. L.; Liu, X.; Yoshii, J.; Hansen, C. J.; Hendrix, A.; Esposito, L. W.

    2014-12-01

    The Hall et al. (1995) report announcing the discovery of atomic oxygen FUV emission from Europa included a conclusion that the atmosphere was dominated by O2. Over the following 20 years publications referencing the atmosphere accepted this conclusion, and calculations of rates, particularly mass loading of the magnetosphere depended on a composition that was of order 90% O2. Analysis of the Europa emission spectrum in the present work, leads to the conclusion that the O I emission properties were misinterpreted. The interpretation of the source process depends on the ratio of the O I 1356 and 1304 A multiplet emissions (R(4:5) = (I(1356)/I(1304)). The value of R(4:5) never reaches the lower limit for electron impact dissociation of O2 for any of the 7 recorded disk averaged measurements between 1994 and 2013. Analysis of the Cassini UVIS exposures show the 1304 A multiplet to be optically thick, and the emissions are modeled as direct electron and solar photon excitation of O I. The result is a model atmosphere dominated by O I and O II, with neutral density a factor of 100 below the original O2 model. Other considerations show incompatibility with an O2 atmosphere. Deep exposures using the Cassini UVIS EUV spectrograph provide the state of the plasma sheet at Europa. The ion species are identified as mainly outwardly diffused mass from the Io plasma torus with a minor contribution from Europa. Plasma time-constants are of the order of 200 days. Neutral species in the plasma sheet are not measureable. The energy flux in the magnetosphere L-shells are mainly responsible for energy deposition maintaining the plasma sheet. The energy content in the Io and Europa L-shells, as measured, is similar, but the mean radiative cooling rate in the Io plasma torus at the time of the Cassini encounter was 565 femtoergs cm-3 s-1, compared to 7.3 at Europa, reflecting the difference between an active and inactive planetary satellite, particularly considering the fact that most

  17. Exospheric signatures of alkalis abundances in Europa's regolith

    NASA Astrophysics Data System (ADS)

    Cipriani, F.; Leblanc, F.; Witasse, O.; Cassidy, T.; Johnson, R. E.

    2008-12-01

    Sputtering of Europa's surface material by Jupiter's magnetospheric plasma results in a strong coupling between the moon's exosphere and its surface content (Johnson 2001). In particular, the presence of alkalis in Europa's exosphere (Brown and Hill 1996, Brown 2001, Brown 2004, Leblanc et al 2005; Cassidy et al. 2008), sputtered from potential surface salts embedded in the icy regolith, supports the hypothesis of a geologically young surface associated with a subsurface ocean. We have carried out test-particle simulations of the ejection of sodium and potassium atoms from the icy matrix of Europa, by both magnetospheric ions and electrons sputtering and desorption stimulated by UV solar photons (hereafter noted PSD). We show that a minimal surface source term of sodium of 3x106cm-2.s-1 is required to produce the average emission intensities observed at different positions of Europa's orbit around Jupiter, in good agreement with Leblanc et al 2002. We also obtain that PSD alone can not account for the emission brightness variations reported in Leblanc et al (2005), as suggested earlier. Instead we propose that a plasma transient corresponding to a global increase of the flux of particles impacting the surface by a factor of about 8 compared to the ambient energetic ions and electrons flux during 10 hours would be sufficient to explain the observed emission enhancement (Cipriani et al 2008). At altitudes typically lower than 500km, we observe that the surface content produces clear asymmetries of the exospheric density from trailing to leading hemispheres consistent with the Cassini observations of Europa in eclipse (Cassidy et al. 2008). We investigate those asymmetries and relate them to signatures of surface processes such as PSD, or surface inhomogeneities and density gradients of sodium. Of particular importance is the estimated Na/K ratio at Europa, whose estimated values close to 20 support the hypothesis of endogenic processes releasing sodium bearing

  18. The Detectability of Heat Flow Signatures on Europa

    NASA Astrophysics Data System (ADS)

    Paige, D. A.; Hayne, P. O.; Spencer, J. R.; Greenhagen, B. T.; Bennett, K. A.; Mellon, M. T.; Bandfield, J. L.; Aharonson, O.

    2014-12-01

    Europa is planetary body with a young, tectonically active ice shell and a subsurface liquid water ocean. These characteristics make it one of the most promising places in the solar system to search for extant life beyond Earth. Conventional wisdom dictates that temperatures at the surface of Europa's ice shell are not expected to exceed 130K, which is well below the stability temperature of liquid water or brines. However, the regional or local-scale surface temperatures on Europa could be elevated due to regional or local scale heat flow anomalies as manifested by regional variations in tidal heating, recent cracks in the ice shell, or episodic eruptive plumes. Using a sophisticated ray-tracing thermal model developed for the moon and Mercury, we have explored the potential detectability of a range of heat flow anomalies on Europa from remote sensing measurements of the thermal emission and solar reflection from the Europa's surface. We find that the thermal emission signatures of potential heat flow anomalies can be differentiated from those caused by topography, roughness, exposed ice blocks and Jupiter shine. We further quantify the requirements for accuracy and signal-to-noise, as well as the requirements, for spatial, spectral and diurnal coverage, and conclude that heat flow signatures from sites of recent plume activity should be readily detectable, even if they are not currently active.

  19. Toward Nutritional Enhancement of Sorghum for Africa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain sorghum (Sorghum bicolor L. Moench) is the fifth most important cereal worldwide. Sorghum is used primarily for animal feed in the developed world but, particularly in semi-arid regions of Africa and Asia, it is a principal source of energy and protein for millions of the poorest people. While...

  20. Studies for the Europagenic Plasma Source in Jupiter's Inner Magnetosphere during the Galileo Europa Mission

    NASA Technical Reports Server (NTRS)

    Smyth, William H.

    2004-01-01

    Progress in research to understand the three-dimensional nature of the Europagenic plasma torus is summarized. Efforts to improve the plasma torus description near Europa's orbit have included a better understanding of Europa's orbit and an improved description of the planetary magnetic field. New plasma torus chemistry for molecular and atomic species has been introduced and implemented in Europa neutral cloud models. Preliminary three-dimensional model calculations for Europa's neutral clouds and their plasma sources are presented.

  1. Neurology in Asia.

    PubMed

    Tan, Chong-Tin

    2015-02-10

    Asia is important as it accounts for more than half of the world population. The majority of Asian countries fall into the middle income category. As for cultural traditions, Asia is highly varied, with many languages spoken. The pattern of neurologic diseases in Asia is largely similar to the West, with some disease features being specific to Asia. Whereas Asia constitutes 60% of the world's population, it contains only 20% of the world's neurologists. This disparity is particularly evident in South and South East Asia. As for neurologic care, it is highly variable depending on whether it is an urban or rural setting, the level of economic development, and the system of health care financing. To help remedy the shortage of neurologists, most counties with larger populations have established training programs in neurology. These programs are diverse, with many areas of concern. There are regional organizations serving as a vehicle for networking in neurology and various subspecialties, as well as an official journal (Neurology Asia). The Asian Epilepsy Academy, with its emphasis on workshops in various locations, EEG certification examination, and fellowships, may provide a template of effective regional networking for improving neurology care in the region. PMID:25666629

  2. Dark and Bright Ridges on Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This high-resolution image of Jupiter's moon Europa, taken by NASA's Galileo spacecraft camera, shows dark, relatively smooth region at the lower right hand corner of the image which may be a place where warm ice has welled up from below. The region is approximately 30 square kilometers in area. An isolated bright hill stands within it. The image also shows two prominent ridges which have different characteristics; youngest ridge runs from left to top right and is about 5 kilometers in width (about 3.1 miles). The ridge has two bright, raised rims and a central valley. The rims of the ridge are rough in texture. The inner and outer walls show bright and dark debris streaming downslope, some of it forming broad fans. This ridge overlies and therefore must be younger than a second ridge running from top to bottom on the left side of the image. This dark 2 km wide ridge is relatively flat, and has smaller-scale ridges and troughs along its length.

    North is to the top of the picture, and the sun illuminates the surface from the upper left. This image, centered at approximately 14 degrees south latitude and 194 degrees west longitude, covers an area approximately 15 kilometers by 20 kilometers (9 miles by 12 miles). The resolution is 26 meters (85 feet) per picture element. This image was taken on December 16, 1997 at a range of 1300 kilometers (800 miles) by Galileo's solid state imaging system.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  3. Terrain on Europa under Changing Lighting Conditions

    NASA Technical Reports Server (NTRS)

    1997-01-01

    These images obtained by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft show the same region of Europa under different lighting conditions. The upper image was obtained on June 28th, 1996 during Galileo's first orbit around Jupiter under 'high-sun' conditions -- the equivalent of taking a picture from a high altitude at noon (with the sun directly overhead). Note that albedo (light/dark) features are emphasized. Compare this to the lower image containing a higher-resolution inset. This (inset) image was taken on November 6th, 1996 during the spacecraft's third orbit under 'low-sun' illumination -- the equivalent of taking a picture from a high altitude at sunrise or sunset. Note that in this image the albedo features are not readily apparent. Instead, the topography of the terrain is emphasized. Planetary geologists use information from images acquired under a variety of lighting conditions to identify different types of structures and interpret how they formed. Note that the bright linear features in the upper image are seen to be ridges in the lower image. The circular feature on the right side of both images, Cilix, is approximately 25 kilometers (15 miles) across.

    The area seen in the upper image is 312 kilometers (187 miles) by 570 kilometers (342 miles) across; the area covered by the inset is 36 kilometers (22 miles) by 315 kilometers (190 miles) across. Both of these images are centered near 2 South latitude, 185 West longitude. North is to the top of the frames.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  4. Tides on Europa: The membrane paradigm

    NASA Astrophysics Data System (ADS)

    Beuthe, Mikael

    2015-03-01

    Jupiter's moon Europa has a thin icy crust which is decoupled from the mantle by a subsurface ocean. The crust thus responds to tidal forcing as a deformed membrane, cold at the top and near melting point at the bottom. In this paper I develop the membrane theory of viscoelastic shells with depth-dependent rheology with the dual goal of predicting tidal tectonics and computing tidal dissipation. Two parameters characterize the tidal response of the membrane: the effective Poisson's ratio ν bar and the membrane spring constant Λ, the latter being proportional to the crust thickness and effective shear modulus. I solve membrane theory in terms of tidal Love numbers, for which I derive analytical formulas depending on Λ, ν bar , the ocean-to-bulk density ratio and the number k2∘ representing the influence of the deep interior. Membrane formulas predict h2 and k2 with an accuracy of a few tenths of percent if the crust thickness is less than one hundred kilometers, whereas the error on l2 is a few percents. Benchmarking with the thick-shell software SatStress leads to the discovery of an error in the original, uncorrected version of the code that changes stress components by up to 40%. Regarding tectonics, I show that different stress-free states account for the conflicting predictions of thin and thick shell models about the magnitude of tensile stresses due to nonsynchronous rotation. Regarding dissipation, I prove that tidal heating in the crust is proportional to Im (Λ) and that it is equal to the global heat flow (proportional to Im (k2)) minus the core-mantle heat flow (proportional to Im (k2∘)). As an illustration, I compute the equilibrium thickness of a convecting crust. More generally, membrane formulas are useful in any application involving tidal Love numbers such as crust thickness estimates, despinning tectonics or true polar wander.

  5. Orbit Determination Covariance Analysis for the Europa Clipper Mission

    NASA Technical Reports Server (NTRS)

    Ionasescu, Rodica; Martin-Mur, Tomas; Valerino, Powtawche; Criddle, Kevin; Buffington, Brent; McElrath, Timothy

    2014-01-01

    A new Jovian satellite tour is proposed by NASA, which would include numerous flybys of the moon Europa, and would explore its potential habitability by characterizing the existence of any water within and beneath Europa's ice shell. This paper describes the results of a covariance study that was undertaken on a sample tour to assess the navigational challenges and capabilities of such a mission from an orbit determination (OD) point of view, and to help establish a delta V budget for the maneuvers needed to keep the spacecraft on the reference trajectory. Additional parametric variations from the baseline case were also investigated. The success of the Europa Clipper mission will depend on the science measurements that it will enable. Meeting the requirements of the instruments onboard the spacecraft is an integral part of this analysis.

  6. Exogenic and endogenic albedo and color patterns on Europa

    NASA Technical Reports Server (NTRS)

    Mcewen, A. S.

    1986-01-01

    New global and high-resolution multispectral mosaics of Europa have been produced from the Voyager imaging data. Photometric normalizations are based on multiple-image techniques that explicitly account for intrinsic albedo variations through pixel-by-pixel solutions. The exogenic color and albedo pattern on Europa is described by a second-order function of the cosine of the angular distance from the apex of orbital motion. On the basis of this second-order function and of color trends that are different on the leading and trailing hemispheres, the exogenic pattern is interpreted as being due to equilibrium between two dominant processes: (1) impact gardening and (2) magnetospheric interactions, including sulfur-ion implantation and sputtering redistribution. Removal of the model exogenic pattern in the mosaics reveals the endogenic variations, consisting of only two major units: darker (redder) and bright materials. Therefore Europa's visual spectral reflectivity is simple, having one continuous exogenic pattern and two discrete endogenic units.

  7. Measurement of the Atmospheres of Europa, Ganymede, and Callisto

    NASA Astrophysics Data System (ADS)

    Wurz, P.; Vorburger, A.; Galli, A.; Tulej, M.; Thomas, N.; Alibert, Y.; Barabash, S.; Wieser, M.; Lammer, H.

    2014-04-01

    The European Space Agency has selected the Jupiter Icy Moons Explorer (JUICE) mission to fly to the Jupiter system and to visit the icy moons Europa, Ganymede, and Callisto. One of the selected scientific instruments is the Particle Environment Package (PEP) that includes a Neutral gas and Ion mass spectrometer (NIM). NIM will measure the composition of the exospheres of these three moons during flybys and in orbit of Ganymede. We present Monte Carlo calculations of Europa's exosphere including all relevant processes to release particles into the exosphere, which are sublimation, sputtering, and the plume release. For the surface composition we compiled composition data from existing spectroscopic observations and from formation models. We derive density profiles for different scenarios (e.g. day/night, in co-rotation flow, ...), and make predictions on the expected NIM measurements for the planned Europa flyby trajectories of JUICE .

  8. Exploration and protection of Europa's biosphere: implications of permeable ice.

    PubMed

    Greenberg, Richard

    2011-03-01

    Europa has become a high-priority objective for exploration because it may harbor life. Strategic planning for its exploration has been predicated on an extreme model in which the expected oceanic biosphere lies under a thick ice crust, buried too deep to be reached in the foreseeable future, which would beg the question of whether other active satellites might be more realistic objectives. However, Europa's ice may in fact be permeable, with very different implications for the possibilities for life and for mission planning. A biosphere may extend up to near the surface, making life far more readily accessible to exploration while at the same time making it vulnerable to contamination. The chances of finding life on Europa are substantially improved while the need for planetary protection becomes essential. The new National Research Council planetary protection study will need to go beyond its current mandate if meaningful standards are to be put in place. PMID:21417946

  9. In Pursuit of Analogs for Europa's Dynamics & Potential Habitats

    NASA Astrophysics Data System (ADS)

    Schmidt, Britney E.; Blankenship, D. D.; Greenbaum, J. S.; Young, D. A.

    2010-10-01

    Future Europa exploration will seek to characterize the distribution of shallow subsurface water as well as to understand the formation of surface features through dynamic ice-shell processes. Radar sounding will be a critical tool for imaging these features, and should be of primary interest to the astrobiology community for understanding how and where life might arise on Europa. To develop successful instrumentation and data interpretation techniques for exploring Europa, we must leverage analogous terrestrial environments and processes. Airborne ice penetrating radar is now a mature tool in terrestrial studies of Earth's ice sheets, and orbital examples have been successfully deployed at Earth's Moon and Mars. It is a distinct possibility that water within or just below the ice on Europa has played a role in forming some of its dynamic terrain. Observations of rotated blocks and dark floor materials may suggest that brines existed in the near subsurface and enabled the formation of such features. The University of Texas High Capability Airborne Radar Sounder (HiCARS) developed to study Antarctic ice sheet dynamics has been configured to test observation scenarios for Europa. We discuss recent results from the 60 MHz HiCARS system over brine infiltrated Antarctic marine ice as an analog for processes affecting the formation of pits and chaos. Basal melt occurring below terrestrial marine ice is directly analogous to processes that may operate on Europa if the shell is "thin,” and will be similar to processes occurring instead within the ice sheet in the case of a thicker, multi-layer ice sheet where enriched brines may remain liquid within the shell. A key site for further investigation of conductive and "convective” ices is found in the polythermal glaciers in the Arctic, and the case for this exploration will be illuminated.

  10. Science and Reconnaissance from the Europa Clipper Mission

    NASA Astrophysics Data System (ADS)

    Prockter, L. M.; Pappalardo, R. T.; Senske, D.; Vance, S.; Patterson, G.; Paczkowski, B.; Goldstein, B.; Magner, T. J.; Cooke, B.

    2013-12-01

    The Europa Clipper mission concept is the subject of a NASA-funded study by a joint JPL/APL science and technical team. The Clipper spacecraft would launch in the 2021 timeframe and would be placed in orbit around Jupiter to perform a detailed investigation of Europa, a world that shows strong evidence for a liquid water ocean beneath its icy crust, and which could host conditions favorable for life. As envisioned, a highly capable, radiation-tolerant spacecraft with a diverse instrument suite would make repeated close flybys of Europa. The Europa Clipper science objectives are: (1) Ocean and Ice Shell - Characterize the ice shell and any subsurface water, including their heterogeneity, ocean properties, and the nature of surface-ice-ocean exchange; (2) Composition - Understand the habitability of Europa's ocean through composition and chemistry; (3) Geology - Understand the formation of surface features, including sites of recent or current activity, and characterize high science interest localities. To maximize success of potential future landed missions, the Europa Clipper would include a reconnaissance capability. Reconnaissance objectives are: (1) Landing Safety - Assess the distribution of surface hazards, the load-bearing capacity of the surface, the structure of the subsurface, and the regolith thickness for specific surface sites; (2) Scientific Value - Assess the composition of surface materials, the geologic context of the surface, the potential for geologic activity, the proximity of near surface water, and the potential for active upwelling of ocean material for the reconnaissance sites. We here present updates on the mission concept, the current encounter trajectory, and science and reconnaissance objectives.

  11. The Mapping Imaging Spectrometer for Europa (MISE) Investigation

    NASA Astrophysics Data System (ADS)

    Blaney, D. L.; Hibbitts, C.; Clark, R. N.; Dalton, J. B., III; Davies, A. G.; Green, R. O.; Hedman, M. M.; Langevin, Y.; Lunine, J. I.; McCord, T. B.; Murchie, S. L.; Paranicas, C.; Seelos, F. P., IV; Soderblom, J. M.; Cable, M. L.

    2015-12-01

    The Mapping Imaging Spectrometer for Europa (MISE) investigation was selected by NASA to be part of the next Europa Mission in May 2015. The MISE instrument is designed to enable the identification and mapping of organics, salts, acid hydrates, water ice phases, altered silicates, and radiolytic compounds at global (≤ 10 km), regional (≤ 300 m), and local scales (~ 25 m). Mapping the composition of specific landforms is critical to understanding surface and subsurface geologic processes, including recent or current activity. High spatial resolution compositional mapping is also essential for detecting small outcrops of organics and salts. Distribution maps of astrobiologically relevant compounds and their geologic context can be used to assess whether Europa's ocean is capable of supporting life. MISE could provide fundamental information on where future Europa landers would have the highest probability of detecting evidence of life. The MISE instrument design is for a high-optical throughput pushbroom imaging spectrometer that could observe effectively throughout a flyby or in orbit around Europa. MISE would cover a spectral range from 0.8-5 μm at 10 nm/channel, with an instantaneous field of view (IFOV) of 250 μrad/pixel and a swath width of 300 active pixels. The 0.8-2.5 μm region is essential for quantifying hydrates and bulk surface composition, while the 3-5 μm region is required for detecting low abundances of organics, most radiolytic products, and discriminating salts from acid hydrates. These longer wavelengths can also be used to measure thermal emissions from currently active regions. MISE is designed to operate within Europa's challenging radiation environment and deal with both radiation noise and total integrated dose. The MISE design is the result of collaboration between NASA's Jet Propulsion Laboratory (California Institute of Technology) and the Applied Physics Laboratory (John Hopkins' University).

  12. NASA's East and Southeast Asia Initiatives: BASE-ASIA and EAST-AIRE

    NASA Technical Reports Server (NTRS)

    Tsay, S.; Maring, H.

    2005-01-01

    Airborne dust from northern China influences air quality and regional climate in Asia during springtime. However, with the economic growth in China, increased emission of particulate air pollutants from industrial and vehicular sources will not only impact the earth's radiation balance, but also adversely affect human health year round. In addition, both of dust and aerosol pollutants can be transported swiftly across the Pacific affecting North America within a few days. Asian dust and pollutant aerosols can be detected by their colored appearance using current Earth observing satellites (e.g., MODIS, SeaWiFS, TOMS, etc.) and by sunphotometers deployed on the surface of the earth. Biomass burning has been a regular practice for land clearing and conversion in many countries, especially those in Africa, South America, and Southeast Asia. However, the climatology of Southeast Asia is very different than that of Africa and South America, such that large-scale biomass burning causes smoke to interact extensively with clouds during the peak-burning season of March to April. Globally significant sources of greenhouse gases (eg., CO2, CH4), chemically active gases (e.g., NO, CO, HC, CH3Br), and atmospheric aerosols are produced by biomass burning. These gases influence the Earth-atmosphere system, impacting both global climate and tropospheric chemistry. Some aerosols can serve as cloud condensation nuclei, which play a role in determining cloud lifetime and precipitation, altering the earth's radiation and water budgets. Biomass burning also affects the biogeochemical cycling of nitrogen and carbon compounds; the hydrological cycle; land surface reflectivity and emissivity; and ecosystem biodiversity and stability. Two NASA initiatives, EAST-AIRE (East Asian Study of Tropospheric Aerosols: an International Regional Experiment) and BASE-ASIA (Biomass-burning Aerosols in South East-Asia: Smoke Impact Assessment) will be presented. The objectives of these initiatives is to

  13. [The population and economic problems of South Asia].

    PubMed

    Gu, J

    1983-07-29

    South Asia, which includes Central South Asia, Southeast Asia, and Southwest Asia, had a comparatively higher population growth rate during the 30-year postwar period because of the overall backward economy and strong religious tradition. From the viewpoint of economics, the high population growth in South Asia has slowed down economic growth, increased the foreign trade imblance, and worsened poverty. Secondly, the rapid population growth has overburdened the area's educational system. The illiteracy rate has been going up continuously because of inadequate funds available for education. Thirdly, young labor is lacking in skills, training, and work experience, and related productivity has declined. Consequently, profits, the investment capability, and wages are also declining. The problems of the oversupply of labor, unemployment, and poverty have also become increasingly serious. In addition, the rapid population growth has intensified the pressure on the food supply and worsened the average nutrition of the general public. In recent years, countries in South Asia have been trying to deal with various problems caused by the rapid population growth. Measures have been taken to control the population growth, with a redistribution of the population to places outside cities, and export labor to oil-producing nations of the Middle East and Africa in order to solve the problem of the domestic labor surplus and earn more income for the foreign exchange. Countries in South Asia need more time and effort to achieve a balance between the population growth and economic development. PMID:12313019

  14. THE JOINT ESA-NASA EUROPA JUPITER SYSTEM MISSION (EJSM)

    NASA Astrophysics Data System (ADS)

    Lebreton, J.; Pappalardo, R. T.; Blanc, M.; Bunce, E. J.; Dougherty, M. K.; Erd, C.; Grasset, O.; Greeley, R.; Johnson, T. V.; Clark, K. B.; Prockter, L. M.; Senske, D. A.

    2009-12-01

    The joint "Europa Jupiter System Mission" (EJSM) is an international mission under study in collaboration between NASA and ESA. Its goal is to study Jupiter and its magnetosphere, the diversity of the Galilean satellites, the physical characteristics, composition and geology of their surfaces. Europa and Ganymede are two primary targets of the mission. The reference mission architecture consists of the NASA-led Jupiter Europa Orbiter (JEO) and the ESA-led Jupiter Ganymede Orbiter (JGO). The two primary goals of the mission are i) to determine whether the Jupiter system harbors habitable worlds and ii) to characterize the processes within the Jupiter system. The science objectives addressing the first goal are to: i) characterize and determine the extent of subsurface oceans and their relations to the deeper interior, ii) characterize the ice shells and any subsurface water, including the heterogeneity of the ice, and the nature of surface-ice-ocean exchange; iii) characterize the deep internal structure, differentiation history, and (for Ganymede) the intrinsic magnetic field; iv) compare the exospheres, plasma environments, and magnetospheric interactions; v) determine global surface composition and chemistry, especially as related to habitability; vi) understand the formation of surface features, including sites of recent or current activity, and identify and characterize candidate sites for future in situ exploration. The science objectives for addressing the second goal are to: i) understand the Jovian satellite system, especially as context for Europa and Ganymede; ii) evaluate the structure and dynamics of the Jovian atmosphere; iii) characterize processes of the Jovian magnetodisk/magnetosphere; iv) determine the interactions occurring in the Jovian system; and v) constrain models for the origin of the Jupiter system. Both spacecraft would carry a complement of 11-12 instruments launch separately in 2020 and use a Venus-Earth-Earth Gravity Assist (VEEGA

  15. Sulfuric acid on Europa and the radiolytic sulfur cycle

    NASA Technical Reports Server (NTRS)

    Carlson, R. W.; Johnson, R. E.; Anderson, M. S.

    1999-01-01

    A comparison of laboratory spectra with Galileo data indicates that hydrated sulfuric acid is present and is a major component of Europa's surface. In addition, this moon's visually dark surface material, which spatially correlates with the sulfuric acid concentration, is identified as radiolytically altered sulfur polymers. Radiolysis of the surface by magnetospheric plasma bombardment continuously cycles sulfur between three forms: sulfuric acid, sulfur dioxide, and sulfur polymers, with sulfuric acid being about 50 times as abundant as the other forms. Enhanced sulfuric acid concentrations are found in Europa's geologically young terrains, suggesting that low-temperature, liquid sulfuric acid may influence geological processes.

  16. Charged particles on the Earth-Jupiter-Europa spacecraft trajectory

    NASA Astrophysics Data System (ADS)

    Podzolko, M. V.; Getselev, I. V.; Gubar, Yu. I.; Veselovsky, I. S.; Sukhanov, A. A.

    2011-08-01

    Charged particle fluxes on the trajectory of future Russian space research mission to Jupiter and its satellite Europa are investigated. The existing experimental data and models of Jupiter's main magnetic field and radiation belts are summarized. Preliminary results of computations of energetic particle fluxes and radiation doses for each stage of the flight are given. Special attention is paid to estimation of radiation conditions in Europa's orbit and on its surface; influence of the satellite on spatial distribution of the fluxes of charged particles of various energies is studied.

  17. UV Imaging of Europa & Ganymede: Unveiling Satellite Aurora & Electrodynamical Interactions

    NASA Astrophysics Data System (ADS)

    McGrath, Melissa

    1999-07-01

    We propose to obtain dispersed ultraviolet images of Europa and Ganymede using STIS to isolate atomic oxygen {1304 and 1356 Angstrom} and hydrogen {Lyman-Alpha} emissions, to study the interaction of the Jovian magnetosphere with the tenuous oxygen atmospheres of these icy satellites. Previous spectroscopic observations, from both HST {with GHRS} and Galileo, suggest the presence of polar aurorae on Ganymede whose geometry would be clearly delineated in these images. Europa is expected to show an oxygen emission morphology similar to that recently discovered on Io.

  18. Dynamic Ice-Water Interactions Form Europa's Chaos Terrains

    NASA Astrophysics Data System (ADS)

    Blankenship, D. D.; Schmidt, B. E.; Patterson, G. W.; Schenk, P.

    2011-12-01

    Unique to the surface of Europa, chaos terrain is diagnostic of the properties and dynamics of its icy shell. We present a new model that suggests large melt lenses form within the shell and that water-ice interactions above and within these lenses drive the production of chaos. This model is consistent with key observations of chaos, predicts observables for future missions, and indicates that the surface is likely still active today[1]. We apply lessons from ice-water interaction in the terrestrial cryosphere to hypothesize a dynamic lense-collapse model to for Europa's chaos terrain. Chaos terrain morphology, like that of Conamara chaos and Thera Macula, suggests a four-phase formation [1]: 1) Surface deflection occurs as ice melts over ascending thermal plumes, as regularly occurs on Earth as subglacial volcanoes activate. The same process can occur at Europa if thermal plumes cause pressure melt as they cross ice-impurity eutectics. 2) Resulting hydraulic gradients and driving forces produce a sealed, pressurized melt lense, akin to the hydraulic sealing of subglacial caldera lakes. On Europa, the water cannot escape the lense due to the horizontally continuous ice shell. 3) Extension of the brittle ice lid above the lense opens cracks, allowing for the ice to be hydrofractured by pressurized water. Fracture, brine injection and percolation within the ice and possible iceberg toppling produces ice-melange-like granular matrix material. 4) Refreezing of the melt lense and brine-filled pores and cracks within the matrix results in raised chaos. Brine soaking and injection concentrates the ice in brines and adds water volume to the shell. As this englacial water freezes, the now water-filled ice will expand, not unlike the process of forming pingos and other "expansion ice" phenomena on Earth. The refreezing can raise the surface and create the oft-observed matrix "domes" In this presentation, we describe how catastrophic ice-water interactions on Earth have

  19. Southeast Asia: `A robust market`

    SciTech Connect

    Pagano, S.S.

    1997-04-01

    Southeast Asia is emerging as a robust market for exploration and field development activities. While much of the worldwide attention is focused on lucrative deep water drilling and production in the U.S. Gulf of Mexico, Brazil, and West Africa, the burgeoning Pacific Rim region is very much in the spotlight. As the industry approaches the next century. Southeast Asia is a key growth area that will be the focus of extensive drilling and development. Regional licensing activity is buoyant as oil and gas companies continue to express interest in Southeast Asian opportunities. During 1996, about 75 new license awards were granted. This year, at least an equal number of licenses likely will be awarded to international major and independent oil companies. In the past five years, the number of production-sharing contracts and concessions awarded declined slightly as oil companies apparently opted to invest in other foreign markets. Brunei government officials plan to open offshore areas to licensing in 1997, including what may prove to be attractive deep water areas. Indonesia`s state oil company Pertamina will offer 26 offshore tracts under production-sharing and technical assistance contracts this year. Malaysia expects to attract international interest in some 30 blocks it will soon offer under production-sharing terms. Bangladesh expects to call for tenders for an unspecified number of concessions later this year. Nearby, bids were submitted earlier this year to the Australian government for rights to explore 38 offshore areas. Results are expected to be announced by mid-year.

  20. Stroke in Asia.

    PubMed

    Thammaroj, Jureerat; Subramaniam, Valarmathi; Bhattacharya, Joti J

    2005-05-01

    The epidemic of cardiovascular disease across most of Asia is at a different stage from that in the West; the incidence and prevalence of stroke are increasing steadily, associated with nutritional changes and aging of the population. Epidemiologic data, crucial in combating stroke, have been relatively sparse in Asian populations, but a few international collaborative studies on stroke have been in progress for several years. Through these, we now know that ischemic stroke is actually the most frequent type of cerebrovascular accident in Asia, although hemorrhagic stroke remains more common in Asia than in the West. Also, the percentage of ischemic stroke attributable to intracranial vascular disease is much higher than in the West. In Japan and a few other countries, stroke rates are declining; however, increasing rates in most other countries make primary prevention of critical importance in minimizing the severe impact of this epidemic in Asia. PMID:16198940

  1. Pass Over Southeastern Asia

    NASA Video Gallery

    This video over Southeastern Asia was taken by the crew of Expedition 29 aboard the International Space Station. This sequence of shots was taken on Oct. 7, 2011, from 12:41:10 to 12:50:46 GMT, on ...

  2. South Africa

    Atmospheric Science Data Center

    2013-04-16

    ... atmospheric and oceanic conditions. At Elands Bay in South Africa's Western Cape province, about 1000 tons of rock lobsters beached ... red tide. At the same time, people came from across South Africa to gather the undersized creatures for food. The effects of the losses ...

  3. The Ionospheres of Europa, Ganymede, and Callisto

    NASA Astrophysics Data System (ADS)

    Kliore, A. J.; Anabtawi, A.; Nagy, A. F.

    2001-12-01

    The U.S. Galileo spacecraft, which has been in orbit around Jupiter since December, 1995, has provided opportunities to collect s-band radio occultation data using the 70 meter antennas of the NASA/JPL Deep Space Net(DSN) at Goldstone, California, Madrid, Spain, and Canberra, Australia. To date, four occultations and one near-occultation by Europa (J2) have been observed. They have shown the presence of electron plasma having a density near the surface of 10,000 to 20,000 cm-3 (Kliore, et al., Science, 277, 1997). If the underlying neutral atmosphere is assumed to consist of H2O or O2, the maximum neutral density near the surface can be inferred to be about 108 cm-3. Ganymede (J3) has also been observed five times by Galileo radio occultation. The results are almost entirely negative, with only one measurement out of ten yielding a possible observation of an ionosphere having a maximum density of about 5,000 cm-3 at an altitude of about 16 km. The failure to observe an ionosphere on Ganymede is at first glance surprising, in view of the detection of oxygen and hydrogen above its surface (c.f., Hall, et al., Astrophys. J., 499, 1998; Barth, et al., GRL, 24, 1997), and it was thought to be due to the shielding effect of Ganymede's magnetic field upon the impinging particles from Jupiter's magnetosphere. Callisto has occulted Galileo four times, and these observations have produced some interesting results. Of the eight individual measurements , two are negative, and six are positive. Two of those six, show unmistakable classic ionospheric layers, having peak electron densities of 15,000 to 20,000 cm-3 . A closer examination of all of these results has revealed a plausible reason for why some observations yield positive results , and some do not. It appears that in order for an ionosphere to be observed, the trailing hemisphere of the satellite must be in sunlight. In that way, the atmosphere created by sputtering effects of the Jovian magnetosphere can be ionized by

  4. The Burden of Cryptosporidium Diarrheal Disease among Children < 24 Months of Age in Moderate/High Mortality Regions of Sub-Saharan Africa and South Asia, Utilizing Data from the Global Enteric Multicenter Study (GEMS)

    PubMed Central

    Nasrin, Dilruba; Blackwelder, William C.; Wu, Yukun; Farag, Tamer H.; Panchalingam, Sandra; Sur, Dipika; Zaidi, Anita K. M.; Faruque, Abu S. G.; Saha, Debasish; Adegbola, Richard; Alonso, Pedro L.; Breiman, Robert F.; Bassat, Quique; Tamboura, Boubou; Sanogo, Doh; Onwuchekwa, Uma; Manna, Byomkesh; Ramamurthy, Thandavarayan; Kanungo, Suman; Ahmed, Shahnawaz; Qureshi, Shahida; Quadri, Farheen; Hossain, Anowar; Das, Sumon K.; Antonio, Martin; Hossain, M. Jahangir; Mandomando, Inacio; Nhampossa, Tacilta; Acácio, Sozinho; Omore, Richard; Oundo, Joseph O.; Ochieng, John B.; Mintz, Eric D.; O’Reilly, Ciara E.; Berkeley, Lynette Y.; Livio, Sofie; Tennant, Sharon M.; Sommerfelt, Halvor; Nataro, James P.; Ziv-Baran, Tomer; Robins-Browne, Roy M.; Mishcherkin, Vladimir; Zhang, Jixian; Liu, Jie; Houpt, Eric R.; Kotloff, Karen L.; Levine, Myron M.

    2016-01-01

    Background The importance of Cryptosporidium as a pediatric enteropathogen in developing countries is recognized. Methods Data from the Global Enteric Multicenter Study (GEMS), a 3-year, 7-site, case-control study of moderate-to-severe diarrhea (MSD) and GEMS-1A (1-year study of MSD and less-severe diarrhea [LSD]) were analyzed. Stools from 12,110 MSD and 3,174 LSD cases among children aged <60 months and from 21,527 randomly-selected controls matched by age, sex and community were immunoassay-tested for Cryptosporidium. Species of a subset of Cryptosporidium-positive specimens were identified by PCR; GP60 sequencing identified anthroponotic C. parvum. Combined annual Cryptosporidium-attributable diarrhea incidences among children aged <24 months for African and Asian GEMS sites were extrapolated to sub-Saharan Africa and South Asian regions to estimate region-wide MSD and LSD burdens. Attributable and excess mortality due to Cryptosporidium diarrhea were estimated. Findings Cryptosporidium was significantly associated with MSD and LSD below age 24 months. Among Cryptosporidium-positive MSD cases, C. hominis was detected in 77.8% (95% CI, 73.0%-81.9%) and C. parvum in 9.9% (95% CI, 7.1%-13.6%); 92% of C. parvum tested were anthroponotic genotypes. Annual Cryptosporidium-attributable MSD incidence was 3.48 (95% CI, 2.27–4.67) and 3.18 (95% CI, 1.85–4.52) per 100 child-years in African and Asian infants, respectively, and 1.41 (95% CI, 0.73–2.08) and 1.36 (95% CI, 0.66–2.05) per 100 child-years in toddlers. Corresponding Cryptosporidium-attributable LSD incidences per 100 child-years were 2.52 (95% CI, 0.33–5.01) and 4.88 (95% CI, 0.82–8.92) in infants and 4.04 (95% CI, 0.56–7.51) and 4.71 (95% CI, 0.24–9.18) in toddlers. We estimate 2.9 and 4.7 million Cryptosporidium-attributable cases annually in children aged <24 months in the sub-Saharan Africa and India/Pakistan/Bangladesh/Nepal/Afghanistan regions, respectively, and ~202,000 Cryptosporidium

  5. The Speciation of Sulfur in an Ocean on Europa

    NASA Technical Reports Server (NTRS)

    Zolotov, M. Yu.; Shock, E. L.

    2002-01-01

    Stability of native sulfur, iron sulfides, and aqueous sulfur compounds is evaluated at assumed P-T conditions of the Europa's ocean floor. Pyrite, gypsum, and ferric hydroxides can coexist in contact with sulfate-rich oceanic water. Additional information is contained in the original extended abstract.

  6. Workshop on Europa's Icy Shell: Past, Present, and Future

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This volume contains abstracts that have been accepted for presentation at the workshop on Europa's Icy Shell: Past, Present, and Future, February 6-8,2004, Houston, Texas. Administration and publications support for this meeting were provided by the staff of the Publications and Program Services Department at the Lunar and Planetary Institute.

  7. Salts and Radiation Products on the Surface of Europa

    NASA Astrophysics Data System (ADS)

    Brown, M. E.; Hand, K. P.

    2013-04-01

    The surface of Europa could contain the compositional imprint of an underlying interior ocean, but competing hypotheses differ over whether spectral observations from the Galileo spacecraft show the signature of ocean evaporates or simply surface radiation products unrelated to the interior. Using adaptive optics at the W. M. Keck Observatory, we have obtained spatially resolved spectra of most of the disk of Europa at a spectral resolution ∼40 times higher than seen by the Galileo spacecraft. These spectra show a previously undetected distinct signature of magnesium sulfate salts on Europa, but the magnesium sulfate is confined to the trailing hemisphere and spatially correlated with the presence of radiation products like sulfuric acid and SO2. On the leading, less irradiated, hemisphere, our observations rule out the presence of many of the proposed sulfate salts, but do show the presence of distorted water ice bands. Based on the association of the potential MgSO4 detection on the trailing side with other radiation products, we conclude that MgSO4 is also a radiation product, rather than a constituent of a Europa ocean brine. Based on ocean chemistry models, we hypothesize that, prior to irradiation, magnesium is primarily in the form of MgCl2, and we predict that NaCl and KCl are even more abundant, and, in fact, dominate the non-ice component of the leading hemisphere. We propose observational tests of this new hypothesis.

  8. Sulfuric Acid on Europa's Surface and the Radiolytic Sulfur Cycle

    NASA Technical Reports Server (NTRS)

    Carlson, R.; Johnson, R.; Anderson, M.

    1999-01-01

    Galileo infrared spectra of Europa's surface show distorted water bands that have been attributed to hydrated evaporite salts (McCord et al., J. Geophys. Res. 104, 11827, 1999) or to the scattering properties of ice (Dalton and Clark, Bull. Am. Astron. Soc. 30, 1081, 1998).

  9. SALTS AND RADIATION PRODUCTS ON THE SURFACE OF EUROPA

    SciTech Connect

    Brown, M. E.; Hand, K. P.

    2013-04-15

    The surface of Europa could contain the compositional imprint of an underlying interior ocean, but competing hypotheses differ over whether spectral observations from the Galileo spacecraft show the signature of ocean evaporates or simply surface radiation products unrelated to the interior. Using adaptive optics at the W. M. Keck Observatory, we have obtained spatially resolved spectra of most of the disk of Europa at a spectral resolution {approx}40 times higher than seen by the Galileo spacecraft. These spectra show a previously undetected distinct signature of magnesium sulfate salts on Europa, but the magnesium sulfate is confined to the trailing hemisphere and spatially correlated with the presence of radiation products like sulfuric acid and SO{sub 2}. On the leading, less irradiated, hemisphere, our observations rule out the presence of many of the proposed sulfate salts, but do show the presence of distorted water ice bands. Based on the association of the potential MgSO{sub 4} detection on the trailing side with other radiation products, we conclude that MgSO{sub 4} is also a radiation product, rather than a constituent of a Europa ocean brine. Based on ocean chemistry models, we hypothesize that, prior to irradiation, magnesium is primarily in the form of MgCl{sub 2}, and we predict that NaCl and KCl are even more abundant, and, in fact, dominate the non-ice component of the leading hemisphere. We propose observational tests of this new hypothesis.

  10. JUICE Planetary Protection Approach for Europa and Ganymede

    NASA Astrophysics Data System (ADS)

    Titov, Dmitrij; Erd, Christian; Grasset, Olivier

    The JUpiter ICy moons Explorer (JUICE) mission was selected by ESA as the first L-Class Mission in the Cosmic Vision Programme. JUICE is an ESA-led mission to investigate Jupiter, the Jovian system with particular focus on habitability of Ganymede and Europa. The baseline mission architecture assumes development, launch and operation by ESA of a single spacecraft in the Jovian system. JUICE will characterise Ganymede and Europa as planetary objects and potential habitats, study Ganymede, Europa, Callisto and Io in the broader context of the system of Jovian moons, and focus on Jupiter science including the planet, its atmosphere and the magnetosphere as a coupled system. The JUICE planetary protection approach for Europa is to ensure that the probability of impact is less than 10-4 during all phases with a credible impact risk. The JUICE science team has published an analysis demonstrating that there is only a remote chance that contamination carried by a spacecraft could compromise future investigations on Ganymede. This would qualify JUICE as a planetary protection category II mission with respect to the Ganymede phase without any impact constraints.

  11. Searching for less perturbed elliptical orbits around Europa

    NASA Astrophysics Data System (ADS)

    Cardoso dos Santos, J.; Carvalho, J. P. S.; Prado, A. F. B. A.; Vilhena de Moraes, R.

    2015-10-01

    Space missions intending to visit Europa, one of the famous Galilean's moons of Jupiter, are among the most important topics in space activities today. There is an increasing interest in the scientific community to send spacecrafts to be inserted into Europa's orbit, with goals like mapping its surface and gravitational field. From the quality of the observations until the orbital maneuvers, the required aspects for the success of the mission will depend on the orbits used by the spacecraft. The present work searches for less perturbed elliptical orbits around Europa, because they are very important, since these orbits are expected to be more stable to place the spacecraft. The development of the study is based on the net effects of the perturbing forces over the time, evaluated by the integral of those forces with respect to the time. The value of this integral depends both on the dynamical model and the orbit of the spacecraft. Jupiter's third-body perturbation and the J2 and J3 terms of the gravitational potential of Europa are the perturbing forces considered. The results presented here are obtained by performing numerical integrations of the perturbing forces, and they show the locations of the less perturbed orbits.

  12. Europa's crustal biosphere: Implications for exploration and contamination

    NASA Astrophysics Data System (ADS)

    Greenberg, R.; Tufts, B. R.; Hoppa, G. V.; Geissler, P. E.

    2000-10-01

    Physical characterization of Europa's crust shows it to be rich in potentially habitable niches, with several timescales for change that would allow stability for organisms to prosper and still require and drive evolution and adaptation. Studies of tectonics on Europa indicate that tidal stress causes much of the surface cracking, that cracks penetrate through to liquid water (so the ice must be thin), and that cracks continue to be worked by tidal stress. Thus a global ocean is (or was until recently) well linked to the surface. Daily tidal flow (period 10-2 yr) transports substances up and down through the active cracks, mixing surface oxidants and fuels (cometary material) with the oceanic reservoir of endogenic and exogenic substances. Organisms moving with the flow or anchored to the walls could exploit the disequilibrium chemistry, and those within a few meters of the surface could photosynthesize. Cracks remain active for at least 104 yr, but deactivate as nonsynchronous rotation moves them to different stress regimes in <106 yr. Thus, to survive, organisms squeezed into the ocean must migrate to new cracks, and those frozen in place must hibernate. Most sites will remelt and release captive critters within 106 yr based on the prevalence of chaotic terrain, which covers nearly half of Europa. Linkage of the ocean to the surface also could help sustain life in the ocean by delivering oxidants and fuels. Suboceanic volcanism (if any) could provide additional sites and support for life, but is not necessary. Thus Europa's biosphere (habitable if not inhabited) likely extends from within the ocean up to the surface, with important implications for exploration strategies: The problem becomes not how to drill down to the ocean, but rather how to choose an active (or recently active) landing site where the ocean comes to the surface. Exploration resources need to go into high resolution reconnaissance. Also, with its biosphere reaching the surface, Europa may be

  13. Prospects For Earth-Based Measurements Of Europa's Librations

    NASA Astrophysics Data System (ADS)

    Margot, Jean-Luc; Campbell, D. B.; Peale, S. J.

    2010-10-01

    The exploration of Europa is of great interest because it may be hospitable to certain life forms [1]. Several lines of evidence suggest that a subsurface ocean exists beneath an icy shell [2,3], but there is debate about the thickness of the shell [4], which impacts Europa's astrobiological potential. As in the case of Mercury, it may be possible to determine whether an outer shell is decoupled from the interior and to evaluate the shell thickness by measuring the amplitude of forced longitude librations [5,6]. In the simplest configuration of a rigid shell decoupled from a spherically symmetric interior, the libration amplitude is amplified from the nominal value of 18" by C/Cs, where C is the polar moment of inertia of the body and Cs is that of the outer shell that participates in the librations. For a 100-km thick shell, the libration amplitude would reach 200", an estimate that remains valid even in the presence of gravitational coupling between asymmetrical layers [7]. If there are significant departures from rigid behavior, the shell may deform with the ocean underneath and exhibit a libration amplitude of 52" [8]. Europa reaches closest approach in October 2011, offering a once-in-a-decade opportunity to measure spin rate variations by tracking radar speckles, as advocated by Holin [9,10]. Librations of a rigid shell thinner than 100 km would be detectable. We will describe the experimental design and expected sensitivity. References: [1] NRC, Europa Science Strategy, 1999. [2,3] Kivelson et al, Greeley et al, in Jupiter, CUP, 2004. [4] Greenberg, Unmasking Europa, Praxis, 2008. [5] Peale, Nature 262, 1976. [6] Margot et al, Science 316, 2007. [7] van Hoolst et al, Icarus 195, 2008. [8] Goldreich and Mitchell, Icarus, in press. [9] Green, in Radar Astronomy, McGraw-Hill, 1968. [10] Holin, Radiophys. Quant. Elec. 31, 1988.

  14. Exporting vices: smoking in Asia.

    PubMed

    Cutler, B

    1988-08-01

    Marketing statistics of U.S. cigarette exports indicate that despite notable declines in sales at home, sales to foreign countries, especially in Asia, Africa and Latin America, are growing dramatically. World cigarette consumption has doubled since 1960, mainly in less developed countries. In 1987, American tobacco firms increased cigarette exports 76%, or 1 billion in new sales. U.S. smoking dropped in 1985-86 from 30.4 to 26.5% of adults. In Taiwan, tariffs were removed from U.S. cigarettes, lowering prices from $2.86 to 1.30, and raising U.S. imports from $4.4 to 119 million. South Korean trade barriers were removed in May 1988, creating a large market. Japan imports 32% of exported U.S. cigarettes, has 120 million smokers, and is the beneficiary of a massive advertising campaign centered on young people and women. The Asian response to the smoking phenomenon is emerging in the form of restrictions on timing of TV advertising (Japan and Taiwan), health warnings (Japan and Taiwan), and restriction of smoking in public places (Hong Kong). PMID:12315861

  15. Africa: "Yonondio."

    ERIC Educational Resources Information Center

    Bendetson, Jane

    1996-01-01

    Recounts a teacher's experiences on a trip to Africa. Describes her pleasant moments with her fellow travelers; her appreciation of the natural setting; her visit to an impoverished native school; and her confrontation with a Maasai warrior. (TB)

  16. A panel of 74 AISNPs: Improved ancestry inference within Eastern Asia.

    PubMed

    Li, Cai-Xia; Pakstis, Andrew J; Jiang, Li; Wei, Yi-Liang; Sun, Qi-Fan; Wu, Hong; Bulbul, Ozlem; Wang, Ping; Kang, Long-Li; Kidd, Judith R; Kidd, Kenneth K

    2016-07-01

    Many ancestry informative SNP (AISNP) panels have been published. Ancestry resolution in them varies from three to eight continental clusters of populations depending on the panel used. However, none of these panels differentiates well among East Asian populations. To meet this need, we have developed a 74 AISNP panel after analyzing a much larger number of SNPs for Fst and allele frequency differences between two geographically close population groups within East Asia. The 74 AISNP panel can now distinguish at least 10 biogeographic groups of populations globally: Sub-Saharan Africa, North Africa, Europe, Southwest Asia, South Asia, North Asia, East Asia, Southeast Asia, Pacific and Americas. Compared with our previous 55-AISNP panel, Southeast Asia and North Asia are two newly assignable clusters. For individual ancestry assignment, the likelihood ratio and ancestry components were analyzed on a different set of 500 test individuals from 11 populations. All individuals from five of the test populations - Yoruba (YRI), European (CEU), Han Chinese in Henan (CHNH), Rondonian Surui (SUR) and Ticuna (TIC) - were assigned to their appropriate geographical regions unambiguously. For the other test populations, most of the individuals were assigned to their self-identified geographical regions with a certain degree of overlap with adjacent populations. These alternative ancestry components for each individual thus help give a clearer picture of the possible group origins of the individual. We have demonstrated that the new AISNP panel can achieve a deeper resolution of global ancestry. PMID:27077960

  17. Effect of Ice Anelasticity on Europa's Tidal Response

    NASA Astrophysics Data System (ADS)

    Castillo, Julie; Johnson, Torrence

    2010-05-01

    Most models of Europa's tidal response have been based on the assumption that Europa behaves as a Maxwell body. However, the Maxwell model is inadequate at reproducing the response of planetary material to cyclic stressing because it does not account for anelasticity. For the conditions of temperature, and cyclic stressing and frequencies affecting planetary satellites, material anelasticity may dominate tidal response. The attenuation spectrum of silicates has been much studied by means of laboratory experiments and theoretical models of ice microphysics. These studies indicate that the Andrade model provides a better representation for silicates viscoelastic and anelasticity. Research on planetary ices attenuation properties has received less support, especially from experimental work. However, available literature, relevant to terrestrial studies, suggests that the Andrade model also provides a good match to experimental measurement of ice attenuation properties. The present study will apply the Andrade model to the modeling of Europa's tidal response. This model will explore the range of possible parameters available on ice and rock properties, available in the literature. For the ice, the range of parameters will also be constrained by experimental work developed in the Planetary Tides Simulation Facility (PTSF - JPL). In that framework, the tidal response depends on cyclic stress, viscoelastic structure, and two parameters that account for the nature, density, and geometry of the material defects and the relaxation time of the material. Empirical relationships between these different parameters are being constrained with the PTSF experiment for dislocation-and grain boundary sliding- driven anelasticity. From ranging a wide parameter space, we have determined conditions for which anelasticity becomes the dominant mechanism accommodating tidal stress and driving internal dissipation (tidal heating). Our survey of the parameter space indicates that ice

  18. Phyllosilicates and Cometary Impacts on the Surface of Europa

    NASA Astrophysics Data System (ADS)

    Shirley, J. H.; Kamp, L. W.; Dalton, J. B.

    2013-12-01

    Near-infrared imaging of Jupiter's moon Europa obtained during the Galileo Mission reveals a 30-km-diameter multi-ring structure near Europa's equator at ~100° W longitude, near the orbital leading-side apex (http://photojournal.jpl.nasa.gov/catalog/PIA02561). Spectral absorption features of phyllosilicate minerals are detected in a discontinuous annulus of lower-albedo materials located at a mean distance of ~120 km from the center of the feature. Other diagnostic spectral absorption features are detected in possible impact melt deposits that line the putative crater floor. Transport to the surface of hydrated layer silicate minerals from Europa's interior is unlikely, due to the ~100-km-thick watery barrier that separates Europa's surface from its rocky mantle. However, two complementary mechanisms exist whereby cometary impacts may account for the presence and areal distribution of phyllosilicates and related materials within our study area. Oblique impacts of active or inactive cometary nuclei may disperse fragmented but chemically unaltered phyllosilicates from the least-shocked portions of the body of the impactor (Pierazzo and Melosh 2000; Met. Plan. Sci. 35, 117). The high temperatures and pressures attained during cometary impacts will in addition vaporize silicates from more highly shocked leading-edge locations within the impactor, to thereafter yield hydrated impact glasses and their alteration products, plausibly including phyllosilicates and other materials. Impact modeling (after Kraus et al. 2011; Icarus 214, 724) provides quantitative support for delivery and emplacement of material sufficient to account for the near-infrared signatures observed, while the nuclei of Jupiter family comets such as Halley and Tempel 1 exhibit compositions with the requisite abundance of silicates. Successful delivery by impacts of solid-phase phyllosilicates to the surface of Europa raises the possibility that carbonaceous materials from the impactor may likewise

  19. Literature of Southeast Asia.

    ERIC Educational Resources Information Center

    Echols, John M.

    This paper provides a brief description of the literature of Southeast Asia. This area, which embraces the region south of China and east of India, includes the modern nations of Burma, Thailand, Cambodia, Laos, Vietnam, The Philippines, Malaysia and Indonesia. The earliest historical influence came from India around the beginnings of the…

  20. OCLC in Asia Pacific.

    ERIC Educational Resources Information Center

    Chang, Min-min

    1998-01-01

    Discusses the Online Computer Library Center (OCLC) and the changing Asia Pacific library scene under the broad headings of the three phases of technology innovation. Highlights include WorldCat and the OCLC shared cataloging system; resource sharing and interlibrary loan; enriching OCLC online catalog with Asian collections; and future outlooks.…

  1. Multicultural Central Asia.

    ERIC Educational Resources Information Center

    Boyle, Eric D.

    This article addresses the multicultural aspect of Central Asia in response to the discussion on diversity in U.S. classrooms. Many areas of the world are more diverse than the U.S., and these areas experience successes and failures with many of the same issues the U.S. is currently struggling with. Comparing the U.S. diversity debate with similar…

  2. HRD Issues in Asia.

    ERIC Educational Resources Information Center

    1998

    This document contains four papers from a symposium on human resource development (HRD) issues in Asia. "The Japanese Human Resource Development System" (Kiyoe Harada) provides a comprehensive model of the Japanese HRD system based on the current state of the art, including management practices and issues and trends in Japanese HRD. "Structured…

  3. Yellow fever, Asia and the East African slave trade.

    PubMed

    Cathey, John T; Marr, John S

    2014-05-01

    Yellow fever is endemic in parts of sub-Saharan Africa and South America, yet its principal vectors--species of mosquito of the genus Aedes--are found throughout tropical and subtropical latitudes. Phylogenetic analyses indicate that yellow fever originated in Africa and that its spread to the New World coincided with the slave trade, but why yellow fever has never appeared in Asia remains a mystery. None of several previously proposed explanations for its absence there is considered satisfactory. We contrast the trans-Atlantic slave trade, and trade across the Sahara and to the Arabian Peninsula and Mesopotamia, with that to Far East and Southeast Asian ports before abolition of the African slave trade, and before the scientific community understood the transmission vector of yellow fever and the viral life cycle, and the need for shipboard mosquito control. We propose that these differences in slave trading had a primary role in the avoidance of yellow fever transmission into Asia in the centuries before the 20(th) century. The relatively small volume of the Black African slave trade between Africa and East and Southeast Asia has heretofore been largely ignored. Although focal epidemics may have occurred, the volume was insufficient to reach the threshold for endemicity. PMID:24743951

  4. Can GM sorghum impact Africa?

    PubMed

    Botha, Gerda M; Viljoen, Christopher D

    2008-02-01

    It is said that genetic modification (GM) of grain sorghum has the potential to alleviate hunger in Africa. To this end, millions of dollars have been committed to developing GM sorghum. Current developments in the genetic engineering of sorghum are similar to efforts to improve cassava and other traditional African crops, as well as rice in Asia. On closer analysis, GM sorghum is faced with the same limitations as 'Golden Rice' (GM rice) in the context of combating vitamin A deficiency (VAD) efficiently and sustainably. Thus, it is questionable whether the cost of developing GM sorghum can be justified when compared to the cost of investing in sustainable agricultural practice in Africa. PMID:18191263

  5. Thermo-Chemical Convection in Europa's Icy Shell with Salinity

    NASA Technical Reports Server (NTRS)

    Han, L.; Showman, A. P.

    2005-01-01

    Europa's icy surface displays numerous pits, uplifts, and chaos terrains that have been suggested to result from solid-state thermal convection in the ice shell, perhaps aided by partial melting. However, numerical simulations of thermal convection show that plumes have insufficient buoyancy to produce surface deformation. Here we present numerical simulations of thermochemical convection to test the hypothesis that convection with salinity can produce Europa's pits and domes. Our simulations show that domes (200-300 m) and pits (300-400 m) comparable to the observations can be produced in an ice shell of 15 km thick with 5-10% compositional density variation if the maximum viscosity is less than 10(exp 18) Pa sec. Additional information is included in the original extended abstract.

  6. Tidal reorientation and the fracturing of Jupiter's moon Europa

    NASA Technical Reports Server (NTRS)

    Mcewen, A. S.

    1986-01-01

    The lineaments on Europa are discussed in terms of the orientation of the lineaments relative to the tensile stress trajectories due to tidal distortions and to nonsynchronous rotation. The cracks are noticeable by their darker albedo compared to the presumed water ice surrounding them. The stress trajectories for tidal distortion of a thin elastic shell are superimposed on Mercator projection maps of the lineaments. It is shown that the lineaments are mainly oriented at high angles to the tensile stress trajectories that would be expected for regularly occurring nonsynchronous rotation, i.e., extensional fractures would appear. The reorientation motions which would cause the fractures are estimated. It is suggested that the fractures occur episodically to release stresses built up on the tensile surface of the crust during the continuous nonsynchronous rotation of Europa.

  7. Patterns of fracture and tidal stresses on Europa

    NASA Technical Reports Server (NTRS)

    Helfenstein, P.; Parmentier, E. M.

    1983-01-01

    A comparison of dark band, triple band, and cuspate ridge orientations with the fracture patterns predicted for tidal distortion due to orbital recession and eccentricity is undertaken, to test the hypothesized identification of Europa's lineaments as tidal distortion and planetary volume change fractures. Short, reticule dark bands near the anti-Jove point could be tension cracks caused by orbital eccentricity. Long, arcuate dark bands and triple bands peripheral to the anti-Jove point may be strike-slip faults due to orbital recession. The orientation and distribution of cuspate ridges, if they are compressional, suggests their formation in response to a combination of orbital recession and planetary volume decrease. If surface fracturing is due to tidal deformation, important constraints are exerted by it on Europa's orbital evolution.

  8. Ridges on Europa: Origin by Incremental Ice-Wedging

    NASA Technical Reports Server (NTRS)

    Melosh, H. J.; Turtle, E. P.

    2004-01-01

    The surface of Europa is covered by ridges that display a variety of morphologies . The most common type is characterized by a double ridge divided by an axial trough. These ridges are, in general, narrow (typically only a few km across) and remarkably linear. They are up to a few hundred meters high and the inner and outer slopes appear to stand at the angle of repose . A number of diverse mechanisms have been proposed to explain the formation of these ubiquitous features , although none can fully account for all of their observed characteristics. We propose a different formation theory in which accumulation of material within cracks that open during the extensional phase of the tidal cycle prevents complete closure of the cracks during the tidal cycle s compressional phase. This accumulation deforms the surrounding ice and, in time, results in the growth of a landform remarkably similar to the ridges observed on Europa.

  9. Searching for liquid water in Europa by using surface observatories.

    PubMed

    Khurana, Krishan K; Kivelson, Margaret G; Russell, Christopher T

    2002-01-01

    Liquid water, as far as we know, is an indispensable ingredient of life. Therefore, locating reservoirs of liquid water in extraterrestrial bodies is a necessary prerequisite to searching for life. Recent geological and geophysical observations from the Galileo spacecraft, though not unambiguous, hint at the possibility of a subsurface ocean in the Jovian moon Europa. After summarizing present evidence for liquid water in Europa, we show that electromagnetic and seismic observations made from as few as two surface observatories comprising a magnetometer and a seismometer offer the best hope of unambiguous characterization of the three-dimensional structure of the ocean and the deeper interior of this icy moon. The observatories would also help us infer the composition of the icy crust and the ocean water. PMID:12449858

  10. Signature of Europa's Ocean Density on Gravity Data

    NASA Astrophysics Data System (ADS)

    Castillo, J. C.; Rambaux, N.

    2015-12-01

    Observations by the Galileo mission at Europa and Cassini-Huygens mission at Europa, Ganymede, Callisto, Enceladus, and Titan have found deep oceans at these objects with evidence for the presence of salts. Salt compounds are the products of aqueous alteration of the rock phase under hydrothermal conditions and have been predicted theoretically for these objects per analogy with carbonaceous chondrite parent bodies. Evidence for salt enrichment comes from magnetometer measurements (Galilean satellites), direct detection in the case of Enceladus, and inversion of the gravity data obtained at Titan. While there is direct detection for the presence of chlorides in icy grains ejected from Enceladus, the chemistry of the oceans detected so far, or even their densities, remain mostly unconstrained. However the increased ocean density impacts the interpretation of the tidal Love number k2and this may introduce confusion in the inference of the icy shell thickness from that parameter. We will present estimates of k2for a range of assumptions on Europa's hydrospheric structure that build on geophysical observations obtained by the Galileo mission combined with new models of Europa's interior. These models keep track of the compositions of the hydrated core and oceanic composition in a self-consistent manner. We will also estimate the electrical conductivity corresponding to the modeled oceanic composition. Finally we will explore how combining electromagnetic, topographic, and gravity data can decouple the signatures of the shell thickness and ocean composition on these geophysical observations. Acknowledgement: This work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. Government sponsorship acknowledged.

  11. Europa's Surface Properties from Secondary Crater Depth/Diameter Ratios

    NASA Astrophysics Data System (ADS)

    Bierhaus, Edward B.; Chapman, C. R.; Schenk, P. M.

    2007-10-01

    We find that secondary craters on Europa tend towards smaller depth-to-diameter (d/D) ratios than primary craters, consistent with observations on other cratered surfaces (the Moon and Mars). We measure craters near the resolution limit, so an individual crater profile is noisy and not definitive; however, the aggregate statistics of over 100 profiles demonstrate a systematic trend for shallow profiles. Primary crater collapse from a simple bowl shape to a more shallow profile (or more complex morphology) is a function of material strength and surface gravity: the transition will happen at smaller diameters for weaker surfaces or for those with higher surface gravity. However, secondary craters are usually more shallow at a given diameter than a primary, perhaps due to lower fragment impact speeds or self-burial during multiple, simultaneous impacts (McEwen and Bierhaus 2005). To first order, very cold ice and rock respond similarly to impact cratering, with predictable differences due to differences in strength, equations of state, etc. But Europa's surface is enigmatic: pervasive fracturing suggests a solid, competent material; chaos features and mobility of blocks within chaos suggest fluid-like behavior; radar measurements (Black et al. 2001) support the presence of a porous surface layer, as do thermal inertia models (Spencer 2004) -- though the thermal inertia only addresses the uppermost few cm. The d/D similarity of secondary craters on icy Europa and rocky surfaces (the Moon and Mars), whose surface evolutions are dominated by different processes, implies that either (a) material properties play a small role in the morphology of secondary craters, or (b) whatever processes operate to create Europa's surface features must leave the ice in a form that responds to cratering in a manner consistent with regoliths on other solar system surfaces. NASA Outer Planets Program funds this research.

  12. Search for volatiles on icy satellites. I. Europa

    USGS Publications Warehouse

    Brown, R.H.; Cruikshank, D.P.; Tokunaga, A.T.; Smith, R.G.; Clark, R.N.

    1988-01-01

    New reflectance spectra have been obtained for both the leading and trailing sides of Europa, using the Cooled Grating Array Spectrometer (CGAS) of the NASA Infrared Telescope Facility (IRTF). The spectra are of higher precision than any yet obtained. Spectra of Europa's trailing side (central meridian longitude ???300??) obtained in 1985 show two weak absorptions near 2.2 and 2.3 ??m. Both of these features as well as others are seen in spectra obtained by R. N. Clark, R. B. Singer, P. D. Owensby, and F.P. Fanale (1980a, Bull. Amer. Astron. Soc. 12, 713-714) at similar central meridian longitude. Data obtained with an improved detector array in 1986, however, do not show the absorptions seen in the 1980 and 1985 spectra. It is not clear why the newest data do not show the apparent absorptions seen in previous years, but the suggestion is that either the 1980 and 1985 data are spurious or that the material responsible for the weak absorptions is no longer detectable. Analysis of the 1980 and 1985 data did not reveal any obvious source of systematic error capable of introducing spurious features, but we are skeptical of any explanation that cites transient deposition, movement, and/or destruction of material on Europa's trailing side to account for the nondetection of the features in the 1986 data. If the weak absorptions seen in the 1980 and 1985 data are real, they can be interpreted as indicating the transient spectroscopic presence of a molecular component on Europa's trailing side different from the water ice that is known to be the dominant surface constituent. Further monitoring is required to determine if the apparent absorptions are real. ?? 1988.

  13. Hybrid Simulations of the Plasma Interaction with Europa's Atmosphere

    NASA Astrophysics Data System (ADS)

    Dols, V. J.; Delamere, P. A.; Wilson, R. J.; Weber, T. D.; Crary, F. J.; Bagenal, F.; Cassidy, T. A.

    2013-12-01

    Europa's atmosphere is about 100 times more tenuous than Io. The weaker ambient magnetic field and lower density of incident plasma means that the electrodynamic interaction is also weaker. Consequently, substantial fluxes of torus ions might reach the icy surface and produce radiolytic reactions. Molecular O2 is the dominant atmospheric product of this surface sputtering. Observations of oxygen UV emissions (specifically the ratio of OI 1356A / 1304A emissions) are consistent with an atmosphere that is composed predominately of O2 with a small amount (2%) of atomic O. Galileo observations along flybys close to Europa have revealed the existence of induced currents in a conducting ocean under the icy crust. They also showed that, from flyby to flyby, the plasma interaction is very variable. Asymmetries of the plasma density and temperature in the wake of Europa were also observed and still elude a clear explanation. Galileo mag data also detected ion cyclotron waves, which is an indication of heavy ion pickup close to the moon. We model the interaction between the plasma torus and Europa's atmosphere with a hybrid code, where ions are treated as kinetic particles moving under the Lorentz force and electrons as a fluid leading to a generalized formulation of Ohm's law. We prescribe an O2 atmosphere with a vertical density column consistent with UV observations and model the plasma properties along several Galileo flybys of the moon. We compare our results with the magnetometer observations, PLS electron density observations and a new re-analysis of the PLS plasma measurements (ion density, temperature and bulk flow velocity).

  14. Clathrate hydrates of oxidants in the ice shell of Europa.

    PubMed

    Hand, Kevin P; Chyba, Christopher F; Carlson, Robert W; Cooper, John F

    2006-06-01

    Europa's icy surface is radiolytically modified by high-energy electrons and ions, and photolytically modified by solar ultraviolet photons. Observations from the Galileo Near Infrared Mapping Spectrometer, ground-based telescopes, the International Ultraviolet Explorer, and the Hubble Space Telescope, along with laboratory experiment results, indicate that the production of oxidants, such as H2O2, O2, CO2, and SO2, is a consequence of the surface radiolytic chemistry. Once created, some of the products may be entrained deeper into the ice shell through impact gardening or other resurfacing processes. The temperature and pressure environments of regions within the europan hydrosphere are expected to permit the formation of mixed clathrate compounds. The formation of carbon dioxide and sulfur dioxide clathrates has been examined in some detail. Here we add to this analysis by considering oxidants produced radiolytically on the surface of Europa. Our results indicate that the bulk ice shell could have a approximately 1.7-7.6% by number contamination of oxidants resulting from radiolysis at the surface. Oxidant-hosting clathrates would consequently make up approximately 12-53% of the ice shell by number relative to ice, if oxidants were entrained throughout. We examine, in brief, the consequences of such contamination on bulk ice shell thickness and find that clathrate formation could lead to substantially thinner ice shells on Europa than otherwise expected. Finally, we propose that double occupancy of clathrate cages by O2 molecules could serve as an explanation for the observation of condensed-phase O2 on Europa. Clathrate-sealed, gas-filled bubbles in the near surface ice could also provide an effective trapping mechanism, though they cannot explain the 5771 A (O2)2 absorption. PMID:16805702

  15. Radiolytic Model for Chemical Composition of Europa's Atmosphere and Surface

    NASA Technical Reports Server (NTRS)

    Cooper, John F.

    2004-01-01

    The overall objective of the present effort is to produce models for major and selected minor components of Europa s neutral atmosphere in 1-D versus altitude and in 2-D versus altitude and longitude or latitude. A 3-D model versus all three coordinates (alt, long, lat) will be studied but development on this is at present limited by computing facilities available to the investigation team. In this first year we have focused on 1-D modeling with Co-I Valery Shematovich s Direct Simulation Monte Carlo (DSMC) code for water group species (H2O, O2, O, OH) and on 2-D with Co-I Mau Wong's version of a similar code for O2, O, CO, CO2, and Na. Surface source rates of H2O and O2 from sputtering and radiolysis are used in the 1-D model, while observations for CO2 at the Europa surface and Na detected in a neutral cloud ejected from Europa are used, along with the O2 sputtering rate, to constrain source rates in the 2-D version. With these separate approaches we are investigating a range of processes important to eventual implementation of a comprehensive 3-D atmospheric model which could be used to understand present observations and develop science requirements for future observations, e.g. from Earth and in Europa orbit. Within the second year we expect to merge the full water group calculations into the 2-D version of the DSMC code which can then be extended to 3-D, pending availability of computing resources. Another important goal in the second year would be the inclusion of sulk and its more volatile oxides (SO, SO2).

  16. Post Galileo-Europa-Mission Satellite Tour Design

    NASA Technical Reports Server (NTRS)

    Wilson, M. G.; Johannesen, J. R.; Halsell, C. A.; Haw, R. J.; Pojman, J. L.

    2000-01-01

    The Galileo orbiter mission as originally envisioned would orbit Jupiter eleven times, closely encountering either Europa, Ganymede, or Callisto on ten of those orbits. This nominal or prime mission began with Jupiter orbit insertion on December 7, 1995 and ended as designed ten encounters later on December 1, 1997. An extension to this nominal mission was proposed, developed and accepted in 1997 and was designed to continue orbital operations through an additional two years until December 31, 1999. This follow- on mission, labelled the Galileo Europa Mission, visits Europa eight times, Callisto four times, and ends with two visits to Io. It augments the prime mission by offering many attractive additional opportunities for science, especially remote sensing. The opportunities include increased scrutiny of Europa, a world with a possible global ocean hidden beneath the surface ice-cap, and the first high resolution images of Io (the only major satellite not encountered during the nominal tour). In 1998 a new effort was begun to investigate a possible extension to GEM. Remote sensing observations will continue to be important but moreover, valuable unique in situ fields and particles measurements will be a high priority motivation in the design and selection of any post-GEM tour. A significant design feature of a possible post-GEM tour would be the extension of the mission through the December 2000 timeframe. This would permit the possibility of simultaneous fields and particles experiments coordinated with the Cassini spacecraft as it swings by the Jupiter system for the final gravity assist enroute to Saturn.

  17. Radar signal propagation through the ionosphere of Europa

    NASA Astrophysics Data System (ADS)

    Grima, Cyril; Blankenship, Donald D.; Schroeder, Dustin M.

    2015-11-01

    We review the current state of knowledge of the Europan plasma environment, its effects on radio wave propagation, and its impact on the performance and design of future radar sounders for the exploration of Europa's ice crust. The Europan ionosphere is produced in two independently-rotating hemispheres by photo-ionization of the neutral exosphere and interaction with the Io plasma torus, respectively. This combination is responsible for temporal and longitudinal ionospheric heterogeneities not well constrained by observations. When Europa's ionosphere is active, the maximum cut-off frequency is 1 MHz at the surface. The main impacts on radar signal propagation are dispersive phase shift and Faraday rotation, both a function of the total electron content (up to 4×1015 m-2) and the Jovian magnetic field strength at Europa (~420 nT). The severity of these impacts decrease with increasing center frequency and increase with altitude, latitude, and bandwidth. The 9 MHz channels on the Radar for Icy Moons Exploration (RIME) and proposed Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) will be sensitive to the Europan ionosphere. For these or similar radar sounders, the ionospheric signal distortion from dispersive phase shift can be corrected with existing techniques, which would also enable the estimation of the total electron content below the spacecraft. At 9 MHz, the Faraday fading is not expected to exceed 6 dB under the worst conditions. At lower frequencies, any active or passive radio probing of the ice shell exploration would be limited to frequencies above 1-8 MHz (depending on survey configuration) below which Faraday rotation angle would lead to signal fading and detection ambiguity. Radar instruments could be sensitive to neutrals and electrons added in the exosphere from any plume activity if present.

  18. Evidence for subduction in the ice shell of Europa

    NASA Astrophysics Data System (ADS)

    Kattenhorn, Simon A.; Prockter, Louise M.

    2014-10-01

    Jupiter’s icy moon Europa has one of the youngest planetary surfaces in the Solar System, implying rapid recycling by some mechanism. Despite ubiquitous extension and creation of new surface area at dilational bands that resemble terrestrial mid-ocean spreading zones, there is little evidence of large-scale contraction to balance the observed extension or to recycle ageing terrains. We address this enigma by presenting several lines of evidence that subduction may be recycling surface material into the interior of Europa’s ice shell. Using Galileo spacecraft images, we produce a tectonic reconstruction of geologic features across a 134,000 km2 region of Europa and find, in addition to dilational band spreading, evidence for transform motions along prominent strike-slip faults, as well as the removal of approximately 20,000 km2 of the surface along a discrete tabular zone. We interpret this zone as a subduction-like convergent boundary that abruptly truncates older geological features and is flanked by potential cryolavas on the overriding ice. We propose that Europa’s ice shell has a brittle, mobile, plate-like system above convecting warmer ice. Hence, Europa may be the only Solar System body other than Earth to exhibit a system of plate tectonics.

  19. Lander rocket exhaust effects on Europa regolith nitrogen assays

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.

    2016-08-01

    Soft-landings on large worlds such as Europa or our Moon require near-surface retropropulsion, which leads to impingement of the rocket plume on the surface. Surface modification by such plumes was documented on Apollo and Surveyor, and on Mars by Viking, Curiosity and especially Phoenix. The low temperatures of the Europan regolith may lead to efficient trapping of ammonia, a principal component of the exhaust from monopropellant hydrazine thrusters. Deposited ammonia may react with any trace organics, and may overwhelm the chemical and isotopic signatures of any endogenous nitrogen compounds, which are likely rare on Europa. An empirical correlation of the photometrically-altered regions ('blast zones') around prior lunar and Mars landings is made, indicating A=0.02T1.5, where A is the area in m2 and W is the lander weight (thus, ~thrust) at landing in N: this suggests surface alteration will occur out to a distance of ~9 m from a 200 kg lander on Europa.

  20. EUROPA2: Plan Database Services for Planning and Scheduling Applications

    NASA Technical Reports Server (NTRS)

    Bedrax-Weiss, Tania; Frank, Jeremy; Jonsson, Ari; McGann, Conor

    2004-01-01

    NASA missions require solving a wide variety of planning and scheduling problems with temporal constraints; simple resources such as robotic arms, communications antennae and cameras; complex replenishable resources such as memory, power and fuel; and complex constraints on geometry, heat and lighting angles. Planners and schedulers that solve these problems are used in ground tools as well as onboard systems. The diversity of planning problems and applications of planners and schedulers precludes a one-size fits all solution. However, many of the underlying technologies are common across planning domains and applications. We describe CAPR, a formalism for planning that is general enough to cover a wide variety of planning and scheduling domains of interest to NASA. We then describe EUROPA(sub 2), a software framework implementing CAPR. EUROPA(sub 2) provides efficient, customizable Plan Database Services that enable the integration of CAPR into a wide variety of applications. We describe the design of EUROPA(sub 2) from the perspective of both modeling, customization and application integration to different classes of NASA missions.

  1. The ionosphere of Europa from Galileo radio occultations.

    PubMed

    Kliore, A J; Hinson, D P; Flasar, F M; Nagy, A F; Cravens, T E

    1997-07-18

    The Galileo spacecraft performed six radio occultation observations of Jupiter's Galilean satellite Europa during its tour of the jovian system. In five of the six instances, these occultations revealed the presence of a tenuous ionosphere on Europa, with an average maximum electron density of nearly 10(4) per cubic centimeter near the surface and a plasma scale height of about 240 +/- 40 kilometers from the surface to 300 kilometers and of 440 +/- 60 kilometers above 300 kilometers. Such an ionosphere could be produced by solar photoionization and jovian magnetospheric particle impact in an atmosphere having a surface density of about 10(8) electrons per cubic centimeter. If this atmosphere is composed primarily of O2, then the principal ion is O2+ and the neutral atmosphere temperature implied by the 240-kilometer scale height is about 600 kelvin. If it is composed of H2O, the principal ion is H3O+ and the neutral temperature is about 340 kelvin. In either case, these temperatures are much higher than those observed on Europa's surface, and an external heating source from the jovian magnetosphere is required. PMID:9219689

  2. Interpretation of surface features of Europa obtained from occultations by Io. [astronomical observations - Jupiter (planet)

    NASA Technical Reports Server (NTRS)

    Herzog, A. D.; Beebe, R. F.

    1975-01-01

    Light curves of occultations of Europa by Io were used to generate a crude map of albedo features on Europa. Impact parameters and magnitude ratios for each event were imposed on a model. Residuals between the observed and computed light curves were interpreted as albedo features on Europa. In order to improve the fit between the observations and the model a general polar brightening was employed. The effects of additional albedo features and alternate models are discussed.

  3. Space Weathering Perspectives on Europa Amidst the Tempest of the Jupiter Magnetospheric System

    NASA Technical Reports Server (NTRS)

    Cooper, J. F.; Hartle, R. E.; Lipatov, A. S.; Sittler, E. C.; Cassidy, T. A.; Ip. W.-H.

    2010-01-01

    Europa resides within a "perfect storm" tempest of extreme external field, plasma, and energetic particle interactions with the magnetospheric system of Jupiter. Missions to Europa must survive, functionally operate, make useful measurements, and return critical science data, while also providing full context on this ocean moon's response to the extreme environment. Related general perspectives on space weathering in the solar system are applied to mission and instrument science requirements for Europa.

  4. Mapping the Topography of Europa: The Galileo-Clipper Story

    NASA Astrophysics Data System (ADS)

    Schenk, Paul M.

    2014-11-01

    The renewed effort to return to Europa for global mapping and landing site selection raises the question: What do we know about Europa topography and how do we know it? The question relates to geologic questions of feature formation, to the issue of ice shell thickness, mechanical strength, and internal activity, and to landing hazards. Our topographic data base for Europa is sparse indeed (no global map is possible), but we are not without hope. Two prime methods have been employed in our mapping program are stereo image and shape-from-shading (PC) slope analyses. On Europa, we are fortunate that many PC-DEM areas are also controlled by stereo-DEMs, mitigating the long-wavelength uncertainties in the PC data. Due to the Galileo antenna malfunction, mapping is limited to no more than 20% of the surface, far less than for any of the inner planets. Thirty-seven individual mapping sites have been identified, scattered across the globe, and all have now been mapped. Excellent stereo mapping is possible at all Sun angles, if resolution is below ~350 m. PC mapping is possible at Sun angles greater than ~60 degrees, if emission angles are less than ~40 degrees. The only extended contiguous areas of topographic mapping larger than 150 km across are the two narrow REGMAP mapping mosaics extending pole-to-pole along longitudes 85 and 240 W. These are PC-only and subject to long-wavelength uncertainties and errors, especially in the north/south where oblique imaging produces layover. Key findings include the mean slopes of individual terrain types (Schenk, 2009), topography across chaos (Schenk and Pappalardo, 2004), topography of craters and inferences for ice shell thickness (Schenk, 2002; Schenk and Turtle, 2009), among others. A key discovery, despite the limited data, is that Europan terrains rarely have topographic amplitude greater than 250 meters, but that regionally Europa has imprinted on it topographic amplitudes of +/- 1 km, in the form of raised plateaus and

  5. Gemini near-infrared observations of Europa's Hydrated Surface Materials

    NASA Astrophysics Data System (ADS)

    Tsang, C.; Spencer, J. R.; Grundy, W. M.; Dalton, J. B.

    2012-12-01

    Europa is a highly dynamic icy moon of Jupiter. It is thought the moon harbors a subsurface ocean, with the potential to sustain life, with Europa being a key target of ESA's forthcoming Jupiter Icy Moons Orbiter (JUICE) mission. However, much is not known concerning the chemistry of the subsurface ocean. The surface is dominated by water ice, with a hydrated non-ice material component providing the distinctive albedo contrasts seen at visible and near-infrared wavelengths. These non-ice materials are concentrated at disrupted surface regions, providing a diagnostic probe for the chemistry and characteristics of the liquid ocean beneath. Leading but potentially competing theories on the composition of these hydrated non-ice materials suggest either sulfuric acid-water mixtures (Carlson et al., 1999) or hydrated magnesium/sodium salts (McCord et al., 1999). Recent reanalysis of Galileo-NIMS observations suggest a mixture of both - hydrated salts are present at all longitudes but the sulfuric acid hydrates are localized on the trailing side. We present preliminary analysis of new ground-based Gemini disk-resolved spectroscopy of Europa using the Near-Infrared Integrated Field Spectrometer (NIFS), taken in late 2011, at H (1.49 - 1.80 μm) and K bands (1.99 - 2.40 μm) with spectral resolving powers of ~ 5300. At these NIR wavelengths, with spectral resolution much better than Galileo-NIMS, the spectral absorption and continuum characteristics of these ice and non-ice materials can be separated out. In addition, the spatial resolution potentially allows identification of localized materials whose signature would be diluted in disk-integrated spectra. These observations of the trailing hemisphere use Altair adaptive optics to achieve spatial resolutions of 0.1" (~310 km per pixel) or better, potentially leading to better identification of the non-ice materials and their spatial distributions. References Carlson, R.W., R.E. Johnson, and M.S. Anderson 1999. Sulfuric acid

  6. The ``Perrier Oceans'' Of Europa And Enceladus (Invited)

    NASA Astrophysics Data System (ADS)

    Matson, D.; Johnson, T. V.; Lunine, J. I.; Castillo, J. C.

    2010-12-01

    Icy satellites of the outer solar system can have subsurface oceans that contain significant amounts of dissolved gases. Crawford and Stevenson in their 1988 study of Europa introduced the term “Perrier Ocean” as a descriptive appellation for such situations. When pressure is reduced, for example as a consequence of faulting, over water from a Perrier ocean, gas comes out of solution in the form of bubbles. The density of the liquid is immediately reduced, and if the bubble volume is sufficient the fluid can become buoyant with respect to the icy crust. If so, the seawater-bubble mixture can rise to the surface or very near to the surface. Europa and Enceladus may represent the end-member examples of Perrier oceans. Today, Europa appears passive whereas Enceladus is erupting. Some characteristics seen at Enceladus that may be indicative of an active Perrier ocean are eruptive plumes and localized, relatively warm (“hot-spot”) thermal anomalies of significantly high heat flow (i.e., >15 GW of integrated power over Enceladus’ South Polar Region). Since Enceladus is smaller than Europa it is easier for it to erupt because less work has to be done against gravity to bring water to the surface. Crawford and Stevenson found that under today’s conditions eruptions at Europa would be difficult but not necessarily impossible. However, in the past, when the icy crust was thinner, the interior warmer, eruption of liquid to the surface regions could have been easier. Morphological evidence for past eruptions from a Perrier ocean is not necessarily unambiguous in that it may admit alternate interpretations. However, the best evidence for relatively recent activity may be some sort of thermal signature. Such anomalies may be observable to depths of tens of meters in relatively clean ice by space-borne high-precision microwave radiometry and ground-penetrating radar. This work was conducted at the Jet Propulsion Laboratory, California Institute of Technology under

  7. Europa's shallow subsurface: lakes, layers and life? (Invited)

    NASA Astrophysics Data System (ADS)

    Schmidt, B. E.; Soderlund, K. M.; Gooch, B. T.; Blankenship, D. D.

    2013-12-01

    With an icy exterior covering a global ocean, Europa has long been a target of interest in the search for life beyond Earth. A critical question related to the habitability of this icy world is: how does the ice shell recycle? Recent detection of shallow subsurface water lenses or "lakes" joins the evidence that implies Europa is currently active, recycling its ice shell. This new perspective has important astrobiological implications. At a surface age of 40-90 Myr, and about 50% covered by chaos terrain, Europa's resurfacing rate is likely to be very high if water does play a significant role in their formation. Because of the vigor of overturn implied if chaos does form by the collapse of ice above subsurface lenses, it is likely that surface and subsurface materials are well-mixed within the largest and deepest lenses, providing a mechanism for bringing oxidants and other surface contaminants to the deeper ice shell where it can reach the ocean by convective or compositional effects. The timescales over which large lenses refreeze (a few hundred thousand years) are large compared to the timescales for vertical transport (a few tens of thousands of years), while the timescales for smaller lenses are comparable to or shorter than convective timescales but involving smaller impurity loads than for larger more well-mixed sources. Melt lenses are intriguing potential habitats, particularly the larger features. Moreover, their formation likely requires the existence of impurities within the upper ice shell that may be sources of energy for microorganisms. Geomorphic evidence also exists for brine percolation that can disperse fluids both vertically and horizontally through pores and fractures. This process, observed in terrestrial ice shelves, may preserve liquid water within the ice matrix over many kilometers from the source. Horizontal transport of material may produce interconnectivity between distinct regions of Europa, providing a pathway for transferring

  8. 17 CFR Appendix E to Part 43 - Other Commodity Geographic Identification for Public Dissemination Pursuant to § 43.4(d)(4)(iii)

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Russia) Russia Africa Northern Africa Western Africa Eastern Africa Central Africa Southern Africa Asia-Pacific Northern Asia (excluding Russia) Central Asia Eastern Asia Western Asia Southeast Asia...

  9. Acid rain in Asia

    NASA Astrophysics Data System (ADS)

    Bhatti, Neeloo; Streets, David G.; Foell, Wesley K.

    1992-07-01

    Acid rain has been an issue of great concern in North America and Europe during the past several decades. However, due to the passage of a number of recent regulations, most notably the Clean Air Act in the United States in 1990, there is an emerging perception that the problem in these Western nations is nearing solution. The situation in the developing world, particularly in Asia, is much bleaker. Given the policies of many Asian nations to achieve levels of development comparable with the industrialized world—which necessitate a significant expansion of energy consumption (most derived from indigenous coal reserves)—the potential for the formation of, and damage from, acid deposition in these developing countries is very high. This article delineates and assesses the emissions patterns, meteorology, physical geology, and biological and cultural resources present in various Asian nations. Based on this analysis and the risk factors to acidification, it is concluded that a number of areas in Asia are currently vulnerable to acid rain. These regions include Japan, North and South Korea, southern China, and the mountainous portions of Southeast Asia and southwestern India. Furthermore, with accelerated development (and its attendant increase in energy use and production of emissions of acid deposition precursors) in many nations of Asia, it is likely that other regions will also be affected by acidification in the near future. Based on the results of this overview, it is clear that acid deposition has significant potential to impact the Asian region. However, empirical evidence is urgently needed to confirm this and to provide early warning of increases in the magnitude and spread of acid deposition and its effects throughout this part of the world.

  10. Anatomically modern human in Southeast Asia (Laos) by 46 ka

    PubMed Central

    Demeter, Fabrice; Shackelford, Laura L.; Bacon, Anne-Marie; Duringer, Philippe; Westaway, Kira; Sayavongkhamdy, Thongsa; Braga, José; Sichanthongtip, Phonephanh; Khamdalavong, Phimmasaeng; Ponche, Jean-Luc; Wang, Hong; Lundstrom, Craig; Patole-Edoumba, Elise; Karpoff, Anne-Marie

    2012-01-01

    Uncertainties surround the timing of modern human emergence and occupation in East and Southeast Asia. Although genetic and archeological data indicate a rapid migration out of Africa and into Southeast Asia by at least 60 ka, mainland Southeast Asia is notable for its absence of fossil evidence for early modern human occupation. Here we report on a modern human cranium from Tam Pa Ling, Laos, which was recovered from a secure stratigraphic context. Radiocarbon and luminescence dating of the surrounding sediments provide a minimum age of 51–46 ka, and direct U-dating of the bone indicates a maximum age of ∼63 ka. The cranium has a derived modern human morphology in features of the frontal, occipital, maxillae, and dentition. It is also differentiated from western Eurasian archaic humans in aspects of its temporal, occipital, and dental morphology. In the context of an increasingly documented archaic–modern morphological mosaic among the earliest modern humans in western Eurasia, Tam Pa Ling establishes a definitively modern population in Southeast Asia at ∼50 ka cal BP. As such, it provides the earliest skeletal evidence for fully modern humans in mainland Southeast Asia. PMID:22908291

  11. Early evidence of the genus Homo in East Asia.

    PubMed

    Zhu, R X; Potts, R; Pan, Y X; Yao, H T; Lü, L Q; Zhao, X; Gao, X; Chen, L W; Gao, F; Deng, C L

    2008-12-01

    The timing and route of the earliest dispersal from Africa to Eastern Asia are contentious topics in the study of early human evolution because Asian hominin fossil sites with precise age constraints are very limited. Here we report new high-resolution magnetostratigraphic results that place stringent age controls on excavated hominin incisors and stone tools from the Yuanmou Basin, southwest China. The hominin-bearing layer resides in a reverse polarity magnetozone just above the upper boundary of the Olduvai subchron, yielding an estimated age of 1.7Ma. The finding represents the age of the earliest documented presence of Homo, with affinities to Homo erectus, in mainland East Asia. This age estimate is roughly the same as for H. erectus in island Southeast Asia and immediately prior to the oldest archaeological evidence in northeast Asia. Mammalian fauna and pollen obtained directly from the hominin site indicate that the Yuanmou hominins lived in a varied habitat of open vegetation with patches of bushland and forest on an alluvial fan close to a lake or swamp. The age and location are consistent with a rapid southern migration route of initial hominin populations into Eastern Asia. PMID:18842287

  12. South Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of South Africa was acquired on May 14, 2000, by NASA's Moderate-resolution Imaging Spectroradiometer, or MODIS. The image was produced using a combination of the sensor's 250-m and 500-m resolution visible wavelength bands. As part of the opening ceremony to begin the joint U.S.-South Africa SAFARI Field Experiment, NASA presented print copies of this image as GIFts to Dr. Ben Ngubane, Minister of Arts, Science and Technology, and Honorable Advocate Ngoaka Ramathlodi, Premier of the Northern Province, South Africa. The area shown in this image encompasses seven capital cities and a number of the region's distinctive geological features can be seen clearly. Toward the northern (top) central part of the image, the browns and tans comprise the Kalahari Desert of southern Botswana. The Tropic of Capricorn runs right through the heart of the Kalahari and the Botswanan capital city of Gaborone sits on the Limpopo River, southeast of the Kalahari. Along the western coastline of the continent is the country of Namibia, where the Namib Desert is framed against the sea by the Kaokoveld Mountains. The Namibian capital of Windhoek is obscured by clouds. Looking closely in the center of the image, the Orange River can be seen running from east to west, demarcating the boundary between Namibia and South Africa. On the southwestern corner of the continent is the hook-like Cape of Good Hope peninsula and Cape Town, the parliamentary capital of South Africa. Running west to east away from Cape Town are the Great Karroo Mountains. The shadow in this image conveys a sense of the very steep grade of the cliffs along the southern coast of South Africa. Port Elizabeth sits on the southeasternmost point of South Africa, and a large phytoplankton bloom can be seen in the water about 100 miles east of there. Moving northward along the east coast, the Drakensberg Mountains are visible. The two small nations of Lesotho and Swaziland are in this region, completely

  13. Biomass-Burning Aerosols in South East-Asia: Smoke Impact Assessment (BASE-ASIA)

    NASA Technical Reports Server (NTRS)

    Tsay, S.-C.; Hsu, N. C.; King, M. D.; Sun, W.-Y.

    2004-01-01

    Biomass burning has been a regular practice for land clearing and land conversion in many countries, especially those in Africa, South America, and Southeast Asia. However, the unique climatology of Southeast Asia is very different than that of Africa and South America, such that large-scale biomass burning causes smoke to interact extensively with clouds during the peak-burning season of March to April. Significant global sources of greenhouse gases (e.g., CO2, CH4), chemically active gases (e.g., NO, CO, HC, CH3Br), and atmospheric aerosols are produced by biomass burning processes. These gases influence the Earth- atmosphere system, impacting both global climate and tropospheric chemistry. Some aerosols can serve as cloud condensation nuclei, which play an important role in determining cloud lifetime and precipitation, hence, altering the earth s radiation and water budget. Analyses from satellite measurements reveal the reflected solar (emitted thermal) radiation from clouds due to smoke aerosols can be reduced (enhanced) by 100 (20) Watts per square meter over the month of March 2000. In addition, the reduction in cloud spectral reflectance is large enough to lead to significant errors in satellite retrievals of cloud properties (e.g., optical thickness and effective radius). The fresh water distribution in this region is highly dependent on monsoon rainfall; in fact, the predictability of the tropical climate system is much reduced during the boreal spring. Therefore, to accurately assess the impact of smoke aerosols in this region requires continuous observations from satellites, aircraft, ground-based networks and dedicated field experiments. BASE-ASIA initiative has been proposed and will be discussed.

  14. Endurance: The rewards and challenges of landing a spacecraft on Europa

    NASA Astrophysics Data System (ADS)

    Calvin, C.; Rager, A.; Balint, T.; Santiago, D.; Anderson, J.; Cassidy, T.; Chavez-Clemente, D.; Corbett, B. M.; Hammerstein, H.; Hanley, T. R.; Letcher, A.; McGowan, E. M.; McMenamin, D. S.; Murphy, N.; Obland, M. D.; Parker, J. S.; Perron, T.; Petro, N.; Pulupa, M.; Schofield, R.; Sizemore, H. G.

    2005-12-01

    The possibility that a water ocean exists beneath Europa's icy shell makes Europa one of the most likely places in our solar system for life to have formed and prospered. In this study, we discuss ``Endurance,'' a proposed lander mission to Europa, and the issues involved in landing a spacecraft on the surface of Europa. Our lander was designed to meet the science objectives laid out in the JIMO SDT Report, namely to: 1) assess the habitability of the environment beneath the surface of Europa; 2) assess the geochemical and physical structure of the surface of Europa and provide ground truth for orbital studies; and 3) provide ground based geophysical studies of Europa's icy shell. Additionally, the mission is designed to assess surface conditions, such as surface structure and radiation levels, for future Europa lander missions. To achieve these objectives, our proposed science payload includes a seismometer, magnetometer, panoramic camera with multispectral imager, surface grinder (to assess the surface strength), microscopic imager, geochemical analysis device (i.e., GC-MS, PEPE), and radiation sensor. We selected the landing site of Castalia Macula suggested by Prockter and Schenk (2004) because its smooth, dark terrain indicates a young surface that may have resulted from recent interactions with the subsurface ocean. Although much can be learned from this mission, landing on Europa presents many challenges such as radiation, extreme cold, and the need to decontaminate the spacecraft to meet planetary protection requirements. The radiation at the surface of Europa requires that all instruments, with the exception of the magnetometer and the radiation detector, be shielded or contained within a vault. A controlled descent and smart landing software would be required to avoid obstacles, however the propellant required to land this mission significantly reduces the payload mass from the lander's mass allocation. Despite the harsh environment, the Endurance lander

  15. Emerging drug problems in Asia

    PubMed Central

    Bart, Gavin

    2014-01-01

    This session, “Emerging Drug Problems in Asia,” focused on emerging drug problems in Asia. Dr. Juana Tomás-Rosselló discussed “East and Southeast Asia: Emerging Drug Problems and Response” and Dr. Wei J. Chen discussed “Ketamine Use among Regular Tobacco and Alcohol Users as Revealed by Respondent Driven Sampling in Taipei: Prevalence, Expectancy, and Users' Risky Decision Making.” PMID:25267884

  16. Europa Lander Mission: A Challenge to Find Traces of Alien Life

    NASA Astrophysics Data System (ADS)

    Zelenyi, Lev; Korablev, Oleg; Vorobyova, Elena; Martynov, Maxim; Akim, Efraim L.; Zakahrov, Alexander

    2010-01-01

    An international effort dedicated to science exploration of Jupiter system planned by ESA and NASA in the beginning of next decade includes in-depth science investigation of Europa. In parallel to EJSM (Europa-Jupiter System Mission) Russian Space Agency and the academy of Science plan Laplace-Europa Lander mission, which will include the small telecommunication and science orbiter and the surface element: Europa Lander. In-situ methods on the lander provide the only direct possibility to assess environmental conditions, and to perform the search for signatures of life. A critical advantage of such in situ analysis is the possibility to enhance concentration and detection limits and to provide ground truth for orbital measurements. The science mission of the lander is biological, geophysical, chemical, and environmental characterizations of the Europa surface. Remote investigations from the orbit around Europa would not be sufficient to address fully the astrobiology, geodesy, and geology goals. The science objectives of the planned mission, the synergy between the Europa Lander and EJSM mission elements, and a brief description of the Laplace-Europa Lander mission are presented.

  17. A Hydrothermal Origin for the Sulfate-rich Ocean of Europa

    NASA Technical Reports Server (NTRS)

    Zolotov, M. Yu.; Shock, E. L.

    2001-01-01

    Thermodynamic calculations show that formation of a sulfate-rich ocean on Europa might require high-temperature alkaline hydrothermal processes in the oxidized silicate mantle. The ocean on Europa could be thought of as a cooled hydrothermal fluid. Additional information is contained in the original extended abstract.

  18. BOOK REVIEW: Geheimnisvolles Universum - Europas Astronomen entschleiern das Weltall

    NASA Astrophysics Data System (ADS)

    Duerbeck, H. W.; Lorenzen, D. H.

    2002-12-01

    The 25th birthday of ESO, in 1987, was celebrated by the publication of an illustrated popular book, "Exploring the Southern Sky" (Springer-Verlag 1987), which also saw editions in Danish, English, French, German, and Spanish. Written and illustrated by the ESO staff members Svend Laustsen, Claus Madsen and Richard M. West, its many pictures were mainly taken with the ESO 3.6m and Schmidt telescopes. The structure of the book - perhaps at that time somewhat unusual - started with things far away (Universe and galaxies), zoomed in to the Milky Way, and finally reached the Solar System (with a concluding chapter dealing with the La Silla observatory). Now, with the 4 units of the Very Large Telescope in full operation, and on the occasion of ESO's 40th birthday, another jubilee book has appeared: "Geheimnisvolles Universum: Europas Astronomen entschleiern das Weltall", written by the science journalist Dirk H. Lorenzen, of Hamburg, Germany, and prefaced by Catherine Cesarsky, Director General of ESO. Presumably, this book will also soon become available in more languages spoken in ESO member countries. Thus it may be worthwhile to review the first edition, although some readers may like to wait for more easily accessible editions. Before going into details, let me first mention that I find this a very impressing book, great to look at and refreshing to read. With ESO seen through the eyes of a visitor, things gain a perspective that is quite different from that of the previous book, and at least as attractive. It comes as no surprise that the book starts with a visit of ESO's showcase, the Paranal Observatory, and the writer not only notes down his own impressions, but also cites statements of some of the many people that keep Paranal going - technicians and staff astronomers. This mixture of texts provides a good impression of the operations at a large observatory for the general reader. The two more 'astronomical' parts that follow deal with star and planet

  19. Tidal reorientation and the fracturing of Jupiter's moon Europa

    USGS Publications Warehouse

    McEwen, A.S.

    1986-01-01

    The most striking characteristic of Europa is the network of long linear albedo markings over the surface, suggestive of global-scale tectonic processes. Various explanations for the fractures have been proposed: Freezing and expansion of an early liquid water ocean1, planetary expansion due to dehydration of hydrated silicates2, localization by weak points in the crust generated by impacts3, and a combination of stresses due to planetary volume change and tidal distortions from orbital recession and orbital eccentricity4,5. Calculations by Yoder6 and Greenberg and Weidenschilling7 have shown that Europa may rotate slightly more rapidly than the synchronous rate, with a rotation period (reorientation through 360??) ranging from 20 to >103 yr if a liquid mantle is present, or up to 1010 yr if the satellite is essentially solid7. Helfen-stein and Parmentier8 modelled the stresses due to nonsynchronous rotation, and concluded that this could explain the long fractures in part of the anti-jovian hemisphere. In this note, I present a global map of lineaments with long arc lengths (>20?? or 550 km), and compare the lineament orientations to the tensile stress trajectories due to tidal distortions (changes in the lengths of three principal semiaxes) and to nonsynchronous rotation (longitudinal reorientation of two of the principal semiaxes). An excellent orthogonal fit to the lineaments is achieved by the stresses due to nonsynchronous rotation with the axis radial to Jupiter located 25?? east of its present position. This fit suggests that nonsynchronous rotation occurred at some time in Europa's history. ?? 1986 Nature Publishing Group.

  20. Constraints on the detection of cryovolcanic plumes on Europa

    NASA Astrophysics Data System (ADS)

    Quick, Lynnae C.; Barnouin, Olivier S.; Prockter, Louise M.; Patterson, G. Wesley

    2013-09-01

    Surface venting is a common occurrence on several outer solar system satellites. Spacecraft have observed plumes erupting from the geologically young surfaces of Io, Triton and Enceladus. Europa also has a relatively young surface and previous studies have suggested that cryovolcanic eruptions may be responsible for the production of low-albedo deposits surrounding lenticulae and along triple band margins and lineae. Here, we have used the projected thicknesses of these deposits as constraints to determine the lifetimes of detectable cryovolcanic plumes that may have emplaced them. In an effort to explore the feasibility of detection of the particle component of plumes by spacecraft cameras operating at visible wavelengths, we present a conservative model to estimate plume characteristics such as height, eruption velocity, and optical depth under a variety of conditions. We find that cryovolcanic plumes on Europa are likely to be fairly small in stature with heights between 2.5 and 26 km, and eruption velocities between 81 and 261 m/s, respectively. Under these conditions and assuming that plumes are products of steady eruptions with particle radii of 0.5 μm, our model suggests that easily detectable plumes will have optical depths, τ, greater than or equal to 0.04, and that their lifetimes may be no more than 300,000 years. Plume detection may be possible if high phase angle limb observations and/or stereo imaging of the surface are undertaken in areas where eruptive activity is likely to occur. Cameras with imaging resolutions greater than 50 m/pixel should be used to make all observations. Future missions could employ the results of our model in searches for plume activity at Europa.

  1. Regional Mosaic of Chaos and Gray Band on Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This mosaic of part of Jupiter's moon, Europa, shows a region that is characterized by mottled (dark and splotchy) terrain. The images in this mosaic were obtained by Solid State Imaging (CCD) system on NASA's Galileo spacecraft during its eleventh orbit around Jupiter. North is to the top of the image, and the sun illuminates the scene from the right. Prior to obtaining these pictures, the age and origin of mottled terrain were not known. As seen here, the mottled appearance results from areas of the bright, icy crust that have been broken apart (known as 'chaos' terrain), exposing a darker underlying material. This terrain is typified by the area in the upper right-hand part of the image. The mottled terrain represents some of the most recent geologic activity on Europa. Also shown in this image is a smooth, gray band (lower part of image) representing a zone where the Europan crust has been fractured, separated, and filled in with material derived from the interior. The chaos terrain and the gray band show that this satellite has been subjected to intense geological deformation.

    The mosaic, centered at 2.9 degrees south latitude and 234.1 degrees west longitude, covers an area of 365 kilometers by 335 kilometers (225 miles by 210 miles). The smallest distinguishable features in the image are about 460 meters (1500 feet) across. These images were obtained on November 6, 1997, when the Galileo spacecraft was approximately 21,700 kilometers (13,237 miles) from Europa.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. JPL is a division of California Institute of Technology.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo home page at URL http://galileo.jpl.nasa.gov. Background information and educational context can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  2. Europa Global Views in Natural and Enhanced Colors

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This color composite view combines violet, green, and infrared images of Jupiter's intriguing moon, Europa, for a view of the moon in natural color (left) and in enhanced color designed to bring out subtle color differences in the surface (right). The bright white and bluish part of Europa's surface is composed mostly of water ice, with very few non-ice materials. In contrast, the brownish mottled regions on the right side of the image may be covered by hydrated salts and an unknown red component. The yellowish mottled terrain on the left side of the image is caused by some other unknown component. Long, dark lines are fractures in the crust, some of which are more than 3,000 kilometers (1,850 miles) long.

    North is to the top of the picture and the sun fully illuminates the surface. Europa is about 3,160 kilometers (1,950 miles) in diameter, or about the size of Earth's moon. The finest details that can be discerned are 25 kilometers across. The images in this global view were taken in June 1997 at a range of 1.25 million kilometers by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft, during its ninth orbit of Jupiter.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  3. High-Resolution Image of Europa's Ridged Plains

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This spectacular image taken by NASA's Galileo spacecraft camera shows a region of ridged plains on Jupiter's moon Europa. The plains are comprised of many parallel and cross-cutting ridges, commonly in pairs. The majority of the region is of very bright, but darker material is seen primarily in valleys between ridges. Some of the most prominent ridges have dark deposits along their margins and in their central valleys. Some of this dark material probably moved down the flanks of the ridges and has piled up along their bases. The most prominent ridges are about a kilometer in width (less than a mile). In the top right hand corner of the image the end of a dark wide ridge (about 2 kilometers or 1.2 miles across) is visible. Several deep fractures cut through this ridge and continue into the plains. The brightness of the region suggests that frost covers much of Europa's surface. This image looks different from those obtained earlier in Galileo's mission, because this image was taken with the Sun higher in Europa's sky.

    This image was taken on December 16, 1997 at a range of 1,300 kilometers (800 miles) by Galileo's solid state imaging system. North is to the top of the picture, and the Sun illuminates the surface from the upper left. This image, centered at approximately 14 degrees south latitude and 194 degrees west longitude, covers an area approximately 20 kilometers (12 miles) on each side. The resolution is 26 meters (85 feet) per picture element.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  4. Compositional Mapping of the Surfaces of Europa and Ganymede

    NASA Astrophysics Data System (ADS)

    Gruen, Eberhard; Horanyi, M.; Kempf, S.; Krueger, H.; Postberg, F.; Srama, R.; Sternovsky, Z.; Trieloff, M.

    2010-10-01

    The determination of the global surface compositions of Europa and Ganymede is a prime objective of the Europa Jupiter System Mission (EJSM). Classical methods to analyze surfaces of airless planetary objects are IR and gamma ray spectroscopy, and neutron backscatter measurements. Here we present a complementary method to analyze dust particles as samples of planetary objects from which they were released. All airless moons and planets are exposed to the ambient meteoroid bombardment that erodes the surface and generates ejecta particles. The Galileo dust detector (Krueger et al., Icarus, 164, 170, 2003) discovered tenuous ejecta clouds around all Galilean satellites. In-situ mass spectroscopic analysis of these dust particles impacting onto a detector of an orbiting spacecraft reveals their composition. Depending on the altitude from which the dust measurements are taken, the position of origin on the surface can be determined with at least corresponding resolution. Since the detection rates are on the order of thousands per day, spatially resolved maps of the surface composition can be obtained. This `dust spectrometer’ approach provides key chemical and isotopic constraints for varying provinces on the surfaces, leading to better understanding of the body's geological evolution. Traces of mineral or organic components in an ice matrix can be identified and quantified even at low impact speeds >1 km/s. Compositional measurements by the Cassini Cosmic Dust Analyzer of ice grains emitted from Enceladus probed the deep interior of this satellite (Postberg et al., Nature, 459, 1098, 2009). New instrumentation has been developed that meet or exceeded the capabilities in sensitivity and mass resolution of all previous dust analyzers. The deployment of such dust analyzers on the Jupiter Europa Orbiter (JEO) and the Jupiter Ganymede Orbiter (JGO) missions will provide unprecedented information on the surface compositions of these satellites and their potential activity.

  5. Gondwana to Asia: Preface

    NASA Astrophysics Data System (ADS)

    Kwon, Sanghoon; Kim, Sung Won; Santosh, M.

    2014-12-01

    The Korean Peninsula, China, Japan, India, Sri Lanka, and Timor, among other regions, preserve important clues for the tectonic evolution of present-day Asia derived from the break-up of Mesozoic supercontinent Pangea. Evidence for the formation, evolution, and destruction of Earth's first coherent supercontinent Columbia during Paleoproterozoic, followed by the Neoproterozoic Rodinia and late Neoproterozoic-Cambrian Gondwana supercontinents are also recorded in many of these regions. The debates surrounding some of these aspects and the state-of-the-art knowledge from these terranes were the focal themes of discussion during the "2013 Annual Convention of the International Association for Gondwana Research (IAGR) and the 10th Gondwana to Asia International Conference" held at the Korea Institute of Geoscience and Mineral Resources (KIGAM), Korea during September 30th to October 2nd 2013. The conference was attended by more than 200 delegates representing 11 countries. The discussion continued at the "International conference on Continental Dynamics" held in Xian, China during April 2014. This special issue of Journal of Asian Earth Sciences, assembling 24 research papers is an outcome of the deliberations under various sessions of the above conferences. In assembling this special issue, we attempt to provide evidence-driven discussions on the construction and destruction of Precambrian and Paleozoic supercontinents preserved in present-day Asian continents. We also address a variety of themes including magmatic, metamorphic and metallogenic processes, as well as issues related to natural environment. We hope that the papers assembled in this special issue offer new insights into some of the key issues surrounding the geological, geophysical and geodynamic milieu in Asia, and a better understanding of analogous processes in other parts of the world.

  6. Underground laboratories in Asia

    SciTech Connect

    Lin, Shin Ted; Yue, Qian

    2015-08-17

    Deep underground laboratories in Asia have been making huge progress recently because underground sites provide unique opportunities to explore the rare-event phenomena for the study of dark matter searches, neutrino physics and nuclear astrophysics as well as the multi-disciplinary researches based on the low radioactive environments. The status and perspectives of Kamioda underground observatories in Japan, the existing Y2L and the planned CUP in Korea, India-based Neutrino Observatory (INO) in India and China JinPing Underground Laboratory (CJPL) in China will be surveyed.

  7. Labor migration in Asia.

    PubMed

    Martin, P L

    1991-01-01

    "A recent conference sponsored by the United Nations Center for Regional Development (UNCRD) in Nagoya, Japan examined the growing importance of labor migration for four major Asian labor importers (Japan, Hong Kong, Malaysia, and Singapore) and five major labor exporters (Bangladesh, Korea, Pakistan, Philippines, and Thailand).... The conference concluded that international labor migration would increase within Asia because the tight labor markets and rising wages which have stimulated Japanese investment in other Asian nations, for example, have not been sufficient to eliminate migration push and pull forces...." PMID:12316776

  8. Mortality in Asia.

    PubMed

    1981-01-01

    Although the general trend in mortality between 1950 and 1975 in South and East Asia has been downward, there is considerable country-to-country variation in the rate of decline. In countries where combined economic, social, and political circumstances resulted in controlling the disease spectrum (e.g., China, Malaysia, Sri Lanka), mortality levels declined to those seen in low-mortality countries. In most of the large countries of the region however, mortality declined at a slower rate, even slowing down considerably in the 1970's while the death rates remained high (e.g., India, Bangladesh, Thailand, Philippines); this slowing down of mortality level is attributed essentially to the poverty-stricken masses of society which were not able to take advantage of social, technological, and health-promoting behavioral changes conducive to mortality decline. Infant mortality levels, although declining since 1950, followed the same dismal pattern of the general mortality level. The rate varies from less than 10/1000 live births (Japan) to more than 140/1000 (Bangladesh, Laos, Nepal). Generally, rural areas exhibited higher infant mortality than urban areas. The level of child mortality declines with increases in the mother's educational level in Bangladesh, India, Indonesia, Sri Lanka, and Thailand. The largest decline in child mortality occurs when at least 1 parent has secondary education. The premature retardation of mortality decline is caused by several factors: economic development, nutrition and food supply, provision and adequacy of health services, and demographic trends. The outlook for the year 2000 for most of Asia's countries will depend heavily on significant population increases. In most countries, particularly in South Asia, population is expected to increase by 75%, much of it in rural areas and among poorer socioeconomic groups. In view of this, Asia's health planners and policymakers will have to develop health policies which will strike a balance

  9. An Islamic University in Cape Town Grows from Roots in East Asia

    ERIC Educational Resources Information Center

    Lindow, Megan

    2007-01-01

    This article features the International Peace University South Africa in Cape Town. The university, which was established in 2004, resulted from the merger of two local "madrassas", or religious colleges, yet seeks to prepare its students for success in the secular world. Its Islamic roots are not in the Middle East, but in East Asia. Situated on…

  10. Genetic and archaeological perspectives on the initial modern human colonization of southern Asia

    PubMed Central

    Mellars, Paul; Gori, Kevin C.; Carr, Martin; Soares, Pedro A.; Richards, Martin B.

    2013-01-01

    It has been argued recently that the initial dispersal of anatomically modern humans from Africa to southern Asia occurred before the volcanic “supereruption” of the Mount Toba volcano (Sumatra) at ∼74,000 y before present (B.P.)—possibly as early as 120,000 y B.P. We show here that this “pre-Toba” dispersal model is in serious conflict with both the most recent genetic evidence from both Africa and Asia and the archaeological evidence from South Asian sites. We present an alternative model based on a combination of genetic analyses and recent archaeological evidence from South Asia and Africa. These data support a coastally oriented dispersal of modern humans from eastern Africa to southern Asia ∼60–50 thousand years ago (ka). This was associated with distinctively African microlithic and “backed-segment” technologies analogous to the African “Howiesons Poort” and related technologies, together with a range of distinctively “modern” cultural and symbolic features (highly shaped bone tools, personal ornaments, abstract artistic motifs, microblade technology, etc.), similar to those that accompanied the replacement of “archaic” Neanderthal by anatomically modern human populations in other regions of western Eurasia at a broadly similar date. PMID:23754394

  11. Magnetospheric ion sputtering and water ice grain size at Europa

    NASA Astrophysics Data System (ADS)

    Cassidy, T. A.; Paranicas, C. P.; Shirley, J. H.; Dalton, J. B., III; Teolis, B. D.; Johnson, R. E.; Kamp, L.; Hendrix, A. R.

    2013-03-01

    We present the first calculation of Europa's sputtering (ion erosion) rate as a function of position on Europa's surface. We find a global sputtering rate of 2×1027 H2O s-1, some of which leaves the surface in the form of O2 and H2. The calculated O2 production rate is 1×1026 O2 s-1, H2 production is twice that value. The total sputtering rate (including all species) peaks at the trailing hemisphere apex and decreases to about 1/3rd of the peak value at the leading hemisphere apex. O2 and H2 sputtering, by contrast, is confined almost entirely to the trailing hemisphere. Most sputtering is done by energetic sulfur ions (100s of keV to MeV), but most of the O2 and H2 production is done by cold oxygen ions (temperature ∼ 100 eV, total energy ∼ 500 eV). As a part of the sputtering rate calculation we compared experimental sputtering yields with analytic estimates. We found that the experimental data are well approximated by the expressions of Famá et al. for ions with energies less than 100 keV (Famá, M., Shi, J., Baragiola, R.A., 2008. Sputtering of ice by low-energy ions. Surf. Sci. 602, 156-161), while the expressions from Johnson et al. fit the data best at higher energies (Johnson, R.E., Burger, M.H., Cassidy, T.A., Leblanc, F., Marconi, M., Smyth, W.H., 2009. Composition and Detection of Europa's Sputter-Induced Atmosphere, in: Pappalardo, R.T., McKinnon, W.B., Khurana, K.K. (Eds.), Europa. University of Arizona Press, Tucson.). We compare the calculated sputtering rate with estimates of water ice regolith grain size as estimated from Galileo Near-Infrared Mapping Spectrometer (NIMS) data, and find that they are strongly correlated as previously suggested by Clark et al. (Clark, R.N., Fanale, F.P., Zent, A.P., 1983. Frost grain size metamorphism: Implications for remote sensing of planetary surfaces. Icarus 56, 233-245.). The mechanism responsible for the sputtering rate/grain size link is uncertain. We also report a surface composition estimate using

  12. Diatoms on earth, comets, Europa and in interstellar space

    NASA Technical Reports Server (NTRS)

    Hoover, R. B.; Hoover, M. J.; Hoyle, F.; Wickramasinghe, N. C.; Al-Mufti, S.

    1986-01-01

    There exists a close correspondence between the measured infrared properties of diatoms and the infrared spectrum of interstellar dust as observed in the Trapezium nebula and toward the galactic center source GC-IRS 7. Diatoms and bacteria also exhibit an absorbance peak near 2200 A, which is found to agree with the observed ultraviolet absorbance properties of interstellar grains. The observational data are reviewed, and the known properties of diatoms and bacteria are considered. It is suggested that these characteristics are consistent with the concept of a cosmic microbiological system in which these or similar microorganisms might exist on comets, Europa and in interstellar space.

  13. Tether-mission design for multiple flybys of moon Europa

    NASA Astrophysics Data System (ADS)

    Sanmartin, J. R. S.; Charro, M. C.; Sanchez-Arriaga, G. S. A.; Sanchez-Torres, A. S. T.

    2015-10-01

    A tether mission to carry out multiple flybys of Jovian moon Europa is here presented. There is general agreement on elliptic-orbit flybys of Europa resulting in cost to attain given scientific goals lower than if actually orbiting the moon, tethers being naturally fit to fly-by rather than orbit moons1. The present mission is similar in this respect to the Clipper mission considered by NASA, the basic difference lying in location of periapsis, due to different emphasis on mission-challenge metrics. Clipper minimizes damaging radiation-dose by avoiding the Jupiter neighborhood and its very harsh environment; periapsis would be at Europa, apoapsis as far as moon Callisto. As in all past outer-planet missions, Clipper faces, however, critical power and propulsion needs. On the other hand, tethers can provide both propulsion and power, but must reach near the planet to find high plasma density and magnetic field values, leading to high induced tether current, and Lorentz drag and power. The bottom line is a strong radiation dose under the very intense Radiation Belts of Jupiter. Mission design focuses on limiting dose. Perijove would be near Jupiter, at about 1.2-1.3 Jovian radius, apojove about moon Ganymede, corresponding to 1:1 resonance with Europa, so as to keep dose down: setting apojove at Europa, for convenient parallel flybys, would require two perijove passes per flyby (the Ganymede apojove, resulting in high eccentricity, about 0.86, is also less requiring on tether operations). Mission is designed to attain reductions in eccentricity per perijove pass as high as Δe ≈ - 0.04. Due the low gravity-gradient, tether spinning is necessary to keep it straight, plasma contactors placed at both ends taking active turns at being cathodic. Efficiency of capture of the incoming S/C by the tether is gauged by the ratio of S/C mass to tether mass; efficiency is higher for higher tape-tether length and lower thickness and perijove. Low tether bowing due to the Lorentz

  14. Europa's Oxygen Atmosphere: Effects due to Regolith Porosity and Composition

    NASA Astrophysics Data System (ADS)

    Cassidy, T. A.; Johnson, R. E.

    2006-05-01

    The surfaces of "airless" bodies in our solar system are covered by porous regoliths, granular surfaces generated by micrometeor impact. Europa's tenuous neutral atmosphere is generated by UV and plasma irradiation of and sublimation from this regolith. Therefore, in addition to the atmosphere above the surface, there is a substantial amount of gas in the porous regolith. The effect of the regolith on the source processes and sinks are typically neglected in modeling the spatial distribution and composition of the atmosphere. The regolith complicates processes such as sputtering, the ejection of mostly neutral atoms and molecules due to energetic ion flux, because the incident ions encounter surfaces at a variety of angles, rather than one angle as usually assumed. Also, most ejecta produced within a regolith no longer have a direct line to space. If ejecta do not stick to or react with grain surfaces, then it may be safely assumed that the majority of ejecta will interact with grain surfaces before leaving the regolith. Similarly, a returning non-sticking particle experiences numerous interactions with grains below the nominal surface. As compared to a flat, smooth planetary surface, these many interactions enhance the probability of chemical reactions or sticking. F. Leblanc and R.E. Johnson have shown that the sticking coefficient is critical in describing the alkali atmosphere at Mercury and likely Europa. The regolith will also affect the velocity distribution of non-sticking ejecta and atmospheric species, which will affect the population of the Europa neutral torus. In this presentation the effect of regolith on the source and sink processes is demonstrated by generating the gravitationally bound and escaping components of the ballistic Europan atmosphere with and without regolith effects. Assuming that O2 can react in the regolith where there is a high sulfur content, we can generate a morphology roughly consistent with HST observations by McGrath and

  15. Human Missions to Europa and Titan - Why Not?

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This report describes a long-term development plan to enable human exploration of the outer solar system, with a focus on Europa and Titan. These are two of the most interesting moons of Jupiter and Saturn, respectively, because they are the places in the solar system with the greatest potential for harboring extraterrestrial life. Since human expeditions to these worlds are considered impossible with current capabilities, the proposal of a well-organized sequence of steps towards making this a reality was formulated. The proposed Development Plan, entitled Theseus, is the outcome of a recent multinational study by a group of students in the framework of the Master of Space Studies (MSS) 2004 course at the International Space University (ISU). The Theseus Program includes the necessary development strategies in key scientific and technological areas that are essential for identifying the requirements for the exploration of the outer planetary moons. Some of the topics that are analysed throughout the plan include: scientific observations at Europa and Titan, advanced propulsion and nuclear power systems, in-situ resource utilization, radiation mitigation techniques, closed life support systems, habitation for long-term spaceflight, and artificial gravity. In addition to the scientific and technological aspects of the Theseus Program, it was recognized that before any research and development work may begin, some level of program management must be established. Within this chapter, legal issues, national and international policy, motivation, organization and management, economic considerations, outreach, education, ethics, and social implications are all considered with respect to four possible future scenarios which enable human missions to the outer solar system. The final chapter of the report builds upon the foundations set by Theseus through a case study. This study illustrates how such accomplishments could influence a mission to Europa to search for evidence

  16. New Model for Europa's Tidal Response Based after Laboratory Measurements

    NASA Astrophysics Data System (ADS)

    Castillo, J. C.; McCarthy, C.; Choukroun, M.; Rambaux, N.

    2009-12-01

    We explore the application of the Andrade model to the modeling of Europa’s tidal response at the orbital period and for different librations. Previous models have generally assumed that the satellite behaves as a Maxwell body. However, at the frequencies exciting Europa’s tides and librations, material anelasticity tends to dominate the satellite’s response for a wide range of temperatures, a feature that is not accounted for by the Maxwell model. Many experimental studies on the anelasticity of rocks, ice, and hydrates, suggest that the Andrade model usually provides a good fit to the dissipation spectra obtained for a wide range of frequencies, encompassing the tidal frequencies of most icy satellites. These data indicate that, at Europa’s orbital frequency, the Maxwell model overestimates water ice attenuation at temperature warmer than ~240 K, while it tends to significantly underestimate it at lower temperatures. Based on the available data we suggest an educated extrapolation of available data to Europa’s conditions. We compute the tidal response of a model of Europa differentiated in a rocky core and a water-rich shell. We assume various degrees of stratification of the core involving hydrated and anhydrous silicates, as well as an iron core. The water-rich shell of Europa is assumed to be fully frozen, or to have preserved a deep liquid layer. In both cases we consider a range of thermal structures, based on existing models. These structures take into account the presence of non-ice materials, especially hydrated salts. This new approach yields a greater tidal response (amplitude and phase lag) than previously expected. This is due to the fact that a greater volume of material dissipates tidal energy in comparison to models assuming a Maxwell body. Another feature of interest is that the tidal stress expected in Europa is at about the threshold between a linear and non-linear mechanical response of water ice as a function of stress. Increased

  17. Possible problematic situations for the Europa cryorobotic mission

    NASA Astrophysics Data System (ADS)

    Kereszturi, A.

    We analyzed some possible dangerous and problematic situations which can take place during the descend of the Europa exlporer cryorobot inside the ice crust. Our work summarizing the followings: 1. consequences of the differences in the ice thickness and time of descend based on our and other workers' ice thickness estimations, 2. consequences of the tectonic movements in the crust during the descend of the cryorobot, 3. consequences of salt rich diapiric/cryomagmatic intrusions on the descend of the probe, 4. consequences of liquid water bodies inside the ice crust during the descend, 5. usage of the whole cryorobot below the ice crust as a robotic submarine.

  18. Human Missions to Europa and Titan - Why Not?

    NASA Astrophysics Data System (ADS)

    Finarelli, Margaret G.

    2004-04-01

    This report describes a long-term development plan to enable human exploration of the outer solar system, with a focus on Europa and Titan. These are two of the most interesting moons of Jupiter and Saturn, respectively, because they are the places in the solar system with the greatest potential for harboring extraterrestrial life. Since human expeditions to these worlds are considered impossible with current capabilities, the proposal of a well-organized sequence of steps towards making this a reality was formulated. The proposed Development Plan, entitled Theseus, is the outcome of a recent multinational study by a group of students in the framework of the Master of Space Studies (MSS) 2004 course at the International Space University (ISU). The Theseus Program includes the necessary development strategies in key scientific and technological areas that are essential for identifying the requirements for the exploration of the outer planetary moons. Some of the topics that are analysed throughout the plan include: scientific observations at Europa and Titan, advanced propulsion and nuclear power systems, in-situ resource utilization, radiation mitigation techniques, closed life support systems, habitation for long-term spaceflight, and artificial gravity. In addition to the scientific and technological aspects of the Theseus Program, it was recognized that before any research and development work may begin, some level of program management must be established. Within this chapter, legal issues, national and international policy, motivation, organization and management, economic considerations, outreach, education, ethics, and social implications are all considered with respect to four possible future scenarios which enable human missions to the outer solar system. The final chapter of the report builds upon the foundations set by Theseus through a case study. This study illustrates how such accomplishments could influence a mission to Europa to search for evidence

  19. Asia-Pacific Africa-Middle East petroleum directory 1986

    SciTech Connect

    Not Available

    1986-01-01

    This directory contains the names of over 40,000 people in over 100 countries including addresses, phone, cable and telex numbers for companies in drilling, refining, exploration, pipelines, engineering, field services, and construction. Over 10,000 companies are featured. This country-by-country listing includes onshore and offshore fields.

  20. Rural Community Resource Centres: A Feasible Option for Africa?

    ERIC Educational Resources Information Center

    Rosenberg, Diana

    1993-01-01

    Discussion of the information needs of rural people in developing countries focuses on rural community resource centers in Africa. Topics addressed include centers run by the local community versus those run by a public library system; rural resource centers in Sierra Leone; community information centers in Asia; information transfer; and training…

  1. Pharmacovigilance in Asia

    PubMed Central

    Biswas, Pipasha

    2013-01-01

    An increase in drug safety concerns in recent years with some high profile drug withdrawals have led to raising the bar by various stakeholders more importantly by the regulatory authorities. The number of Adverse Drug Reactions (ADRs) reported have also resulted in an increase in the volume of data handled and to understand pharmacovigilance a high level of expertise is required to rapidly detect drug risks as well as to defend the product against an inappropriate removal. Proactive pharmacovigilance throughout the product life cycle is the way forward and the future direction for drug safety in Asia. It has been a constant challenge to standardize pharmacovigilance in Asia, in the context of clinical trials and post-marketing pharmacovigilance due to varied geaographical, cultural and medical practices in these regioon. While major advancements of the discipline of pharmacovigilance have taken place in the West, not much has been achieved in Asian countries, though several attempts have been taken. However, with more clinical trials and clinical research activity being conducted in the Asian continent, there is an immense need to understand and implement pharmacovigilance. For this to happen, the mind set of people working in regulatory agencies, the Pharmaceutical companies, prescribers and patients/consumers need to change. PMID:24347987

  2. Uniportal VATS in Asia

    PubMed Central

    2013-01-01

    The history of uniportal Video-assisted thoracic surgery (VATS) stretches back almost a decade with the treatment of simple thoracic conditions. As the technique matures with increasing ability to tackle the full spectrum of thoracic surgical diseases, most notably major lung resections for lung tumours, the spread of uniportal VATS across the globe has been phenomenal. VATS centres in Asia are now performing uniportal VATS, and developing their individual styles and techniques with great successes. The enthusiasm from surgeons, demand from patients, as well as the dynamism and diversity of uniportal VATS in the region have helped fuel this excitement and change. The 1st Asian Single Port VATS Symposium in 2013 heralded the beginning of academic exchange between uniportal VATS centres in Asia and experts from around the world. Wetlabs in the region will provide further training for thoracic surgeons interested in super-specializing in uniportal VATS. The future of this approach will hinge on good regional collaboration, research and training. PMID:24040529

  3. Will oil palm's homecoming spell doom for Africa's great apes?

    PubMed

    Wich, Serge A; Garcia-Ulloa, John; Kühl, Hjalmar S; Humle, Tatanya; Lee, Janice S H; Koh, Lian Pin

    2014-07-21

    Expansion of oil palm plantations has led to extensive wildlife habitat conversion in Southeast Asia [1]. This expansion is driven by a global demand for palm oil for products ranging from foods to detergents [2], and more recently for biofuels [3]. The negative impacts of oil palm development on biodiversity [1, 4, 5], and on orangutans (Pongo spp.) in particular, have been well documented [6, 7] and publicized [8, 9]. Although the oil palm is of African origin, Africa's production historically lags behind that of Southeast Asia. Recently, significant investments have been made that will likely drive the expansion of Africa's oil palm industry [10]. There is concern that this will lead to biodiversity losses similar to those in Southeast Asia. Here, we analyze the potential impact of oil palm development on Africa's great apes. Current great ape distribution in Africa substantially overlaps with current oil palm concessions (by 58.7%) and areas suitable for oil palm production (by 42.3%). More importantly, 39.9% of the distribution of great ape species on unprotected lands overlaps with suitable oil palm areas. There is an urgent need to develop guidelines for the expansion of oil palm in Africa to minimize the negative effects on apes and other wildlife. There is also a need for research to support land use decisions to reconcile economic development, great ape conservation, and avoiding carbon emissions. PMID:25017207

  4. Designing capture trajectories to unstable periodic orbits around Europa

    NASA Technical Reports Server (NTRS)

    Russell, Ryan P.; Lam, Try

    2006-01-01

    The hostile environment of third body perturbations restricts a mission designer's ability to find well-behaved reproducible capture trajectories when dealing with limited control authority as is typical with low-thrust missions. The approach outlined in this paper confronts this shortcoming by utilizing dynamical systems theory and an extensive preexisting database of Restricted Three Body Problem (RTBP) periodic orbits. The stable manifolds of unstable periodic orbits are utilized to attract a spacecraft towards Europa. By selecting an appropriate periodic orbit, a mission designer can control important characteristics of the captured state including stability, minimum altitudes, characteristic inclinations, and characteristic radii among others. Several free parameters are optimized in the non-trivial mapping from the RTBP to a more realistic model. Although the ephemeris capture orbit is ballistic by design, low-thrust is used to target the state that leads to the capture orbit, control the spacecraft after arriving on the unstable quasi-periodic orbit, and begin the spiral down towards the science orbit. The approach allows a mission designer to directly target fuel efficient captures at Europa in an ephemeris model. Furthermore, it provides structure and controllability to the design of capture trajectories that reside in a chaotic environment.

  5. Contributions to Crustal Mechanics on Europa from Subterranean Ocean Vibrations

    NASA Astrophysics Data System (ADS)

    Hayes, Robert

    2016-03-01

    The recent discovery of subduction zones on Europa demonstrated a significant step forward in understanding the moon's surface mechanics. This work promotes the additional consideration that the surface mechanics have contributions from small relative pressure differentials in the subsurface ocean that create cracks in the surface which are then filled, sealed and healed. Crack formation can be small, as interior pressure can relatively easily breach the surface crust, generating cracks followed by common fracture formation backfilled with frozen liquid. This process will slowly increase the overall surface area of the moon with each sealed crack and fracture increasing the total surface area. This creeping growth of surface area monotonically decreases subsurface pressure which can eventually catastrophically subduct large areas of surface and so is consistent with current knowledge of observational topology on Europa. This tendency is attributed to a relatively lower energy threshold to crack the surface from interior overpressures, but a higher energy threshold to crush the spherical surface due to subsurface underpressures. Proposed mechanisms for pressure differentials include tidal forces whose Fourier components build up the resonant oscillatory modes of the subsurface ocean creating periodic under and overpressure events below the crust. This mechanism provides a means to continually reform the surface of the moon over short geological time scales. This work supported in part by federal Grant NRC-HQ-84-14-G-0059.

  6. Distribution of strike-slip faults on Europa

    NASA Astrophysics Data System (ADS)

    Hoppa, Gregory; Greenberg, Richard; Tufts, B. Randall; Geissler, Paul; Phillips, Cynthia; Milazzo, Moses

    2000-09-01

    Study of four different regions on Europa imaged by the Galileo spacecraft during its first 15 orbits has revealed 117 strike-slip faults. Europa appears to form preferentially right-lateral faults in the southern hemisphere and left-lateral faults in the northern hemisphere. This observation is consistent with a model where diurnal tides due to orbital eccentricity drive strike-slip motion through a process of ``walking,'' in which faults open and close out of phase with alternating right-and left-lateral shear. Lineaments that record both left-and right-lateral motion (e.g., Agave Linea) may record the accommodation of compression in nearby chaotic zones. Nearly all identified strike-slip faults were associated with double ridges or bands, and few were detected along ridgeless cracks. Thus the depth of cracks without ridges does not appear to have penetrated to the low-viscosity decoupling layer, required for diurnal displacement, but cracks that have developed ridges do extend down to such a level. This result supports a model for ridge formation that requires cracks to penetrate to a decoupling layer, such as a liquid water ocean.

  7. Long Period Variations in Tidal and Librational Forcing of Europa

    NASA Technical Reports Server (NTRS)

    Bills, Bruce G.

    2004-01-01

    The gravitational field of Jupiter exerts a profound influence on the energy balance, thermal evolution, and stress regime of Europa. It widely appreciated that dissipation associated with the spheroidal tidal deformation is a major source of heat. Another possibly important source of dissipation is the toroidal deformation field associated with forced librations. Both tidal and librational deformations depend on the distance and direction Jupiter, as seen from Europa. These quantities vary with time as a result of the finite values of orbital eccentricity and spin pole obliquity, though the obliquity effects have been ignored in most previous studies. Variations in eccentricity and obliquity of the Galilean satellites occur on a very wide range of time scales, as angular momentum is exchanged among the orbital and rotational components of the coupled system. The orbital periods are only a few days in length, and the secular changes in orbital period associated with tidal and librational dissipation have characteristic time scales of 10-9 years or longer. On intermediate time scales, the satellites perturb each other, and the Sun and Saturn make additional contributions. The present values of satellite orbital inclinations and obliquities are not particularly representative their respective longer term variations. As a result, the tidal stress and dissipation regimes at present may not provide adequate explanation of the sources of surface features seen on the satellites.

  8. Impact breaching of Europa's ice: Constraints from numerical modeling

    NASA Astrophysics Data System (ADS)

    Cox, Rónadh; Bauer, Aaron W.

    2015-10-01

    Numerical simulations show that impactors can penetrate Europa's ice, creating conduits to the underlying ocean. Breaching becomes inevitable when transient cavity depth exceeds 90% of ice thickness. Results indicate that a 0.5 km comet would penetrate 5 km ice, and a 5 km comet could breach 40 km ice. Thinner ice would be breached more frequently, thicker ice less so, but even the 40 km upper estimates for ice thickness would be penetrated by comets with recurrence intervals less than 250 Ma. If actual ice thickness is 8-13 km (indicated by comparing Europan and simulated crater geometries), the ocean could be exposed by impactors in the range 0.7-1.5 km, which have recurrence intervals ≈3 to 7 Ma. Thus, it seems that Europa's ice has been penetrated often in the past and possibly in geologically recent time. The largest known impact sites, Callanish and Tyre, probably represent transition from craters to penetrating impacts. The geomorphic expression of full penetration must exist on the surface; chaos terrain is a candidate. Astrobiological materials could be transported to the ocean via these impact-created conduits.

  9. Cross-cutting Relationships of Surface Features on Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image of Jupiter's moon Europa shows a very complex terrain of ridges and fractures. The absence of large craters and the low number of small craters indicates that this surface is geologically young. The relative ages of the ridges can be determined by using the principle of cross-cutting relationships; i.e. older features are cross-cut by younger features. Using this principle, planetary geologists are able to unravel the sequence of events in this seemingly chaotic terrain to unfold Europa's unique geologic history.

    The spacecraft Galileo obtained this image on February 20, 1997. The area covered in this image is approximately 11 miles (18 kilometers) by 8.5 miles (14 kilometers) across, near 15 North, 273 West. North is toward the top of the image, with the sun illuminating from the right.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  10. On the design of a science orbit about Europa

    NASA Technical Reports Server (NTRS)

    Lara, Martin; Russell, Ryan

    2006-01-01

    A science mission about Europa requires high-inclination low-altitude orbits. However, perturbations of Jupiter on the orbiter result in instability. Previous approaches to maximize the lifetime of the orbiter use the doubly averaged problem. We work with the unaveraged equations and find unstable periodic orbits with long lifetimes. These low-altitude repeat ground track solutions exist at all inclinations, making them suitable for mapping missions. The governing dynamics include Hill's model and a Europa gravity field based on synchronous moon theory. Inclusion of additional gravity terms is trivial to the solution method, and for the case of J3, we find a marginal impact on orbit lifetime. The science orbits are found to last on the order of 1 year when the initial conditions are achieved to 11 significant digits and 4 months when only 3 significant digits are achieved. Finally, we demonstrate that the solutions are robust in a realistic ephemeris model, finding average lifetimes of 3 to 4 months for wide range of initial conditions with peak lifetimes of up to 6 months.

  11. Very High Resolution Image of Icy Cliffs on Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This image, taken by the camera onboard NASA's Galileo spacecraft, is a very high resolution view of the Conamara Chaos region on Jupiter's moon Europa. It shows an area where icy plates have been broken apart and moved around laterally. The top of this image is dominated by corrugated plateaus ending in icy cliffs over a hundred meters (a few hundred feet) high. Debris piled at the base of the cliffs can be resolved down to blocks the size of a house. A fracture that runs horizontally across and just below the center of the Europa image is about the width of a freeway.

    North is to the top right of the image, and the sun illuminates the surface from the east. The image is centered at approximately 9 degrees north latitude and 274 degrees west longitude. The image covers an area approximately 1.7 kilometers by 4 kilometers (1 mile by 2.5 miles). The resolution is 9 meters (30 feet) per picture element. This image was taken on December 16, 1997 at a range of 900 kilometers (540 miles) by Galileo's solid state imaging system.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  12. Secondary craters on Europa and implications for cratered surfaces.

    PubMed

    Bierhaus, Edward B; Chapman, Clark R; Merline, William J

    2005-10-20

    For several decades, most planetary researchers have regarded the impact crater populations on solid-surfaced planets and smaller bodies as predominantly reflecting the direct ('primary') impacts of asteroids and comets. Estimates of the relative and absolute ages of geological units on these objects have been based on this assumption. Here we present an analysis of the comparatively sparse crater population on Jupiter's icy moon Europa and suggest that this assumption is incorrect for small craters. We find that 'secondaries' (craters formed by material ejected from large primary impact craters) comprise about 95 per cent of the small craters (diameters less than 1 km) on Europa. We therefore conclude that large primary impacts into a solid surface (for example, ice or rock) produce far more secondaries than previously believed, implying that the small crater populations on the Moon, Mars and other large bodies must be dominated by secondaries. Moreover, our results indicate that there have been few small comets (less than 100 m diameter) passing through the jovian system in recent times, consistent with dynamical simulations. PMID:16237437

  13. Europa ocean sampling by plume flythrough: Astrobiological expectations

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.

    2016-03-01

    The anticipated material captured from a flythrough of Europa's putative plumes is investigated using a simple model. With parameters appropriate to observed constraints (plume height 100-200 km, column mass 1E20 H2O molecules/m2, originating in a liquid water exposure), bacterial cells of ∼10 μm could be lofted even to the plume tops, but no particles larger than 2 mm will be lofted above ∼2 km, a likely lower limit on feasible altitude. Intercepted mass densities of 1E-5 to 1E-3 kg/m2 are calculated. With a small in-situ sampler at the lowest altitudes a few hundred cells might be captured if the liquid is as abundant in biota as the richest environments on Earth, but statistically less than 1 cell for Vostok waters, a Europa analog. The imperative for a large collection area is noted. The likelihood of capturing at least a single cell, with a log-uniform prior of cell abundances, is proposed as a science value metric for different flyby altitudes.

  14. Asia Wise Workbook Number One.

    ERIC Educational Resources Information Center

    Tasmanian Education Dept., Hobart (Australia).

    This workbook is a compilation of work sheets from the teacher's sections of the 1989 issues of "Asia Wise," an Auatralian magazine devoted to the study of Asia. Profiles and worksheets are provided for the countries of China, Indo-China, Indonesia, Japan, Philippines, and Thailand. Worksheets feature the following themes: Asian Australians; food…

  15. San Andreas-sized Strike-slip Fault on Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This mosaic of the south polar region of Jupiter's moon Europa shows the northern 290 kilometers (180 miles) of a strike-slip fault named Astypalaea Linea. The entire fault is about 810 kilometers (500 miles) long, about the size of the California portion of the San Andreas fault, which runs from the California-Mexico border north to the San Francisco Bay.

    In a strike-slip fault, two crustal blocks move horizontally past one another, similar to two opposing lanes of traffic. Overall motion along the fault seems to have followed a continuous narrow crack along the feature's entire length, with a path resembling steps on a staircase crossing zones that have been pulled apart. The images show that about 50 kilometers (30 miles) of displacement have taken place along the fault. The fault's opposite sides can be reconstructed like a puzzle, matching the shape of the sides and older, individual cracks and ridges broken by its movements.

    [figure removed for brevity, see original site]

    The red line marks the once active central crack of the fault. The black line outlines the fault zone, including material accumulated in the regions which have been pulled apart.

    Bends in the fault have allowed the surface to be pulled apart. This process created openings through which warmer, softer ice from below Europa's brittle ice shell surface, or frozen water from a possible subsurface ocean, could reach the surface. This upwelling of material formed large areas of new ice within the boundaries of the original fault. A similar pulling-apart phenomenon can be observed in the geological trough surrounding California's Salton Sea, in Death Valley and the Dead Sea. In those cases, the pulled-apart regions can include upwelled materials, but may be filled mostly by sedimentary and eroded material from above.

    One theory is that fault motion on Europa is induced by the pull of variable daily tides generated by Jupiter's gravitational tug on Europa. Tidal tension

  16. A NEW UNDERSTANDING OF THE EUROPA ATMOSPHERE AND LIMITS ON GEOPHYSICAL ACTIVITY

    SciTech Connect

    Shemansky, D. E.; Liu, X.; Yoshii, J.; Yung, Y. L.; Hansen, C. J.; Hendrix, A. R.; Esposito, L. W.

    2014-12-20

    Deep extreme ultraviolet spectrograph exposures of the plasma sheet at the orbit of Europa, obtained in 2001 using the Cassini Ultraviolet Imaging Spectrograph experiment, have been analyzed to determine the state of the gas. The results are in basic agreement with earlier results, in particular with Voyager encounter measurements of electron density and temperature. Mass loading rates and lack of detectable neutrals in the plasma sheet, however, are in conflict with earlier determinations of atmospheric composition and density at Europa. A substantial fraction of the plasma species at the Europa orbit are long-lived sulfur ions originating at Io, with ∼25% derived from Europa. During the outward radial diffusion process to the Europa orbit, heat deposition forces a significant rise in plasma electron temperature and latitudinal size accompanied with conversion to higher order ions, a clear indication that mass loading from Europa is very low. Analysis of far ultraviolet spectra from exposures on Europa leads to the conclusion that earlier reported atmospheric measurements have been misinterpreted. The results in the present work are also in conflict with a report that energetic neutral particles imaged by the Cassini ion and neutral camera experiment originate at the Europa orbit. An interpretation of persistent energetic proton pitch angle distributions near the Europa orbit as an effect of a significant population of neutral gas is also in conflict with the results of the present work. The general conclusion drawn here is that Europa is geophysically far less active than inferred in previous research, with mass loading of the plasma sheet ≤4.5 × 10{sup 25} atoms s{sup –1} two orders of magnitude below earlier published calculations. Temporal variability in the region joining the Io and Europa orbits, based on the accumulated evidence, is forced by the response of the system to geophysical activity at Io. No evidence for the direct injection of H{sub 2}O

  17. Large-scale phytogeographical patterns in East Asia in relation to latitudinal and climatic gradients

    USGS Publications Warehouse

    Qian, H.; Song, J.-S.; Krestov, P.; Guo, Q.; Wu, Z.; Shen, X.; Guo, X.

    2003-01-01

    Aim: This paper aims at determining how different floristic elements (e.g. cosmopolitan, tropical, and temperate) change with latitude and major climate factors, and how latitude affects the floristic relationships between East Asia and the other parts of the world. Location: East Asia from the Arctic to tropical regions, an area crossing over 50?? of latitudes and covering the eastern part of China, Korea, Japan and the eastern part of Russia. Methods: East Asia is divided into forty-five geographical regions. Based on the similarity of their world-wide distributional patterns, a total of 2808 indigenous genera of seed plants found in East Asia were grouped into fourteen geographical elements, belonging to three major categories (cosmopolitan, tropical and temperate). The 50??-long latitudinal gradient of East Asia was divided into five latitudinal zones, each of c. 10??. Phytogeographical relationships of East Asia to latitude and climatic variables were examined based on the forty-five regional floras. Results: Among all geographical and climatic variables considered, latitude showed the strongest relationship to phytogeographical composition. Tropical genera (with pantropical, amphi-Pacific tropical, palaeotropical, tropical Asia-tropical Australia, tropical Asia-tropical Africa and tropical Asia geographical elements combined) accounted for c. 80% of the total genera at latitude 20??N and for c. 0% at latitude 55-60??N. In contrast, temperate genera (including holarctic, eastern Asia-North America, temperate Eurasia, temperate Asia, Mediterranean, western Asia to central Asia, central Asia and eastern Asia geographical elements) accounted for 15.5% in the southernmost latitude and for 80% at 55-60??N, from where northward the percentage tended to level off. The proportion of cosmopolitan genera increased gradually with latitude from 5% at the southernmost latitude to 21% at 55-60??N, where it levelled off northward. In general, the genera present in a more

  18. Drug abuse in Asia.

    PubMed

    Suwanwela, C; Poshyachinda, V

    1986-01-01

    The article focuses on countries and areas of South-East Asia, which are seriously affected by drug abuse and the problems associated with it. Opium has traditionally been used for treating illnesses and alleviating physical and mental stress, as well as for recreational and social purposes. The prohibition of the sale and use of opium in Burma, Hong Kong, Malaysia, Singapore and Thailand forced many habitual opium users to switch to heroin. Over the past two decades there has been an increasing trend towards drug use, often involving experimentation with more than one substance, among youth in and out of school. For example, a survey of students at teachers' colleges in northern Thailand showed that at some time in their lives 30-40 per cent of the male respondents and 3-6 per cent of the female respondents had used cannabis, and that 18-20 per cent of the males and 12-27 per cent of the females had sniffed volatile solvents. The same survey showed that 5-10 per cent of both the males and females had used stimulants and nearly 2 per cent had used heroin. During the 1970s the abuse of heroin and other opiates emerged as a serious problem of epidemic nature, predominantly affecting young people in many countries of South-East Asia. While opiates, including heroin, have been abused by inhaling and by smoking, there has recently been an increasing trend towards injecting heroin of high purity (80-90 per cent pure heroin). Heroin addiction spread first to the populations of capital cities and then to other cities and towns and even to the hill tribes, as studies in Thailand have revealed. Most recent studies have shown that heroin abuse has spread further in Asia, both socially and geographically, involving such countries as India and Sri Lanka, which had no previous experience with the problem. Studies have also shown that the abuse of manufactured psychotropic substances has been increasing and that heroin addicts resort to these substances when heroin is difficult

  19. West Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    With its vast expanses of sand, framed by mountain ranges and exposed rock, northwestern Africa makes a pretty picture when viewed from above. This image was acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. The Canary Islands can be seen on the left side of the image just off Africa's Atlantic shore. The light brown expanse running through the northern two thirds of the image is the Sahara Desert. The desert runs up against the dark brown Haut Atlas mountain range of Morocco in the northwest, the Atlantic Ocean to the west and the semi-arid (light brown pixels) Sahelian region in the South. The Sahara, however, isn't staying put. Since the 1960s, the desert has been expanding into the Sahelian region at a rate of up to 6 kilometers per year. In the 1980s this desert expansion, combined with over cultivation of the Sahel, caused a major famine across west Africa. Over the summer months, strong winds pick up sands from the Sahara and blow them across the Atlantic as far west as North America, causing air pollution in Miami and damaging coral reefs in the Bahamas and the Florida Keys. The white outlines on the map represent country borders. Starting at the top-most portion of the map and working clockwise, the countries shown are Morocco, Western Sahara, Mauritania, Senegal, Mali, Burkina Fasso, Nigeria, Mali (again), and Algeria. Image by Reto Stockli, Robert Simmon, and Brian Montgomery, NASA Earth Observatory, based on data from MODIS

  20. Snakebite nephrotoxicity in Asia.

    PubMed

    Kanjanabuch, Talerngsak; Sitprija, Visith

    2008-07-01

    Snakebites have the highest incidence in Asia and represent an important health problem. Clinical renal manifestations include proteinuria, hematuria, pigmenturia, and renal failure. Nephropathy usually is caused by bites by snakes with hemotoxic or myotoxic venoms. These snakes are Russell's viper, saw-scaled viper, hump-nosed pit viper, green pit viper, and sea-snake. Renal pathologic changes include tubular necrosis, cortical necrosis, interstitial nephritis, glomerulonephritis, and vasculitis. Hemodynamic alterations caused by vasoactive mediators and cytokines and direct nephrotoxicity account significantly for the development of nephropathy. Hemorrhage, hypotension, disseminated intravascular coagulation, intravascular hemolysis, and rhabdomyolysis enhance renal ischemia leading to renal failure. Enzymatic activities of snake venoms account for direct nephrotoxicity. Immunologic mechanism plays a minor role. PMID:18620959

  1. Europa's magnetic signature: report from Galileo's pass on 19 December 1996.

    PubMed

    Kivelson, M G; Khurana, K K; Joy, S; Russell, C T; Southwood, D J; Walker, R J; Polanskey, C

    1997-05-23

    On 19 December 1996 as Galileo passed close to Jupiter's moon, Europa, the magnetometer measured substantial departures from the slowly varying background field of Jupiter's magnetosphere. Currents coupling Europa to Jupiter's magnetospheric plasma could produce perturbations of the observed size. However, the trend of the field perturbations is here modeled as the signature of a Europa-centered dipole moment whose maximum surface magnitude is approximately 240 nanotesla, giving a rough upper limit to the internal field. The dipole orientation is oblique to Europa's spin axis. This orientation may not be probable for a field generated by a core dynamo, but higher order multipoles may be important as they are at Uranus and Neptune. Although the data can be modeled as contributions of an internal field of Europa, they do not confirm its existence. The dipole orientation is also oblique to the imposed field of Jupiter and thus not directly produced as a response to that field. Close to Europa, plasma currents appear to produce perturbations with scale sizes that are small compared with a Europa radius. PMID:9157878

  2. South Africa.

    PubMed

    1985-05-01

    The 1983 population of South Africa was estimated at 31.1 million, with an annual growth rate of 2.5% (0.8% for whites, 1.8% for blacks and "coloreds," 1.8% for Asians, and 2.8% for Africans). The infant mortality rate was 14.9/1000 live births among whites, 80.6/1000 among blacks and coloreds, and 25.3/1000 among Asians. Life expectancy was 70 years for whites, 59 years for blacks and coloreds, 66 years for Asians, and 55 years for Africans. Racial discrimination has become increasingly institutionalized in South Africa since the ruling National Party came to power in 1948. The policy of apartheid calls for separate political institutions for the 4 major racial groups in the population. Africans are considered citizens of the homelands to which their tribal group is assigned, not permanent citizens of the country. Coloreds and Asians are considered citizens and given some political expression. The new political system envisions broad consensus among whites, coloreds, and Indians, and a parliamentary committee is considering possible abolition of laws against multiracial political activity. The work force totals 11 million, 30% of whom are engaged in agriculture, 29% are employed in industry and commerce, 34% work in the services sector, and 7% work in mining. The GNP in 1983 totalled US$75.5 billion and the GDP stood at US$73.2 billion. Per capita GNP was US$5239. PMID:12178120

  3. Tether-mission design for multiple flybys of moon Europa

    NASA Astrophysics Data System (ADS)

    Sanmartin, J. R. S.; Charro, M. C.; Sanchez-Arriaga, G. S. A.; Sanchez-Torres, A. S. T.

    2015-10-01

    A tether mission to carry out multiple flybys of Jovian moon Europa is here presented. There is general agreement on elliptic-orbit flybys of Europa resulting in cost to attain given scientific goals lower than if actually orbiting the moon, tethers being naturally fit to fly-by rather than orbit moons1. The present mission is similar in this respect to the Clipper mission considered by NASA, the basic difference lying in location of periapsis, due to different emphasis on mission-challenge metrics. Clipper minimizes damaging radiation-dose by avoiding the Jupiter neighborhood and its very harsh environment; periapsis would be at Europa, apoapsis as far as moon Callisto. As in all past outer-planet missions, Clipper faces, however, critical power and propulsion needs. On the other hand, tethers can provide both propulsion and power, but must reach near the planet to find high plasma density and magnetic field values, leading to high induced tether current, and Lorentz drag and power. The bottom line is a strong radiation dose under the very intense Radiation Belts of Jupiter. Mission design focuses on limiting dose. Perijove would be near Jupiter, at about 1.2-1.3 Jovian radius, apojove about moon Ganymede, corresponding to 1:1 resonance with Europa, so as to keep dose down: setting apojove at Europa, for convenient parallel flybys, would require two perijove passes per flyby (the Ganymede apojove, resulting in high eccentricity, about 0.86, is also less requiring on tether operations). Mission is designed to attain reductions in eccentricity per perijove pass as high as Δe ≈ - 0.04. Due the low gravity-gradient, tether spinning is necessary to keep it straight, plasma contactors placed at both ends taking active turns at being cathodic. Efficiency of capture of the incoming S/C by the tether is gauged by the ratio of S/C mass to tether mass; efficiency is higher for higher tape-tether length and lower thickness and perijove. Low tether bowing due to the Lorentz

  4. The Contribution of Io-Raised Tides to Europa's Diurnally-Varying Surface Stresses

    NASA Technical Reports Server (NTRS)

    Rhoden, Alyssa Rose; Hurford, Terry A,; Manga, Michael

    2011-01-01

    Europa's icy surface records a rich history of geologic activity, Several features appear to be tectonic in origin and may have formed in response to Europa's daily-varying tidal stress [I]. Strike-slip faults and arcuate features called cycloids have both been linked to the patterns of stress change caused by eccentricity and obliquity [2J[3]. In fact, as Europa's obliquity has not been directly measured, observed tectonic patterns arc currently the best indicators of a theoretically supported [4] non-negligible obliquity. The diurnal tidal stress due to eccentricity is calculated by subtracting the average (or static) tidal shape of Europa generated by Jupiter's gravitational field from the instantaneous shape, which varies as Europa moves through its eccentric orbit [5]. In other words, it is the change of shape away from average that generates tidal stress. One might expect tidal contributions from the other large moons of Jupiter to be negligible given their size and the height of the tides they raise on Europa versus Jupiter's mass and the height of the tide it raises on Europa, However, what matters for tidally-induced stress is not how large the lo-raised bulge is compared to the Jupiter-raised bulge but rather the differences bet\\Veen the instantaneous and static bulges in each case. For example, when Europa is at apocenter, Jupiter raises a tide 30m lower than its static tide. At the same time, 10 raises a tide about 0.5m higher than its static tide. Hence, the change in Io's tidal distortion is about 2% of the change in the Jovian distortion when Europa is at apocenter

  5. Evidence of human infection by a new mammarenavirus endemic to Southeastern Asia.

    PubMed

    Blasdell, Kim R; Duong, Veasna; Eloit, Marc; Chretien, Fabrice; Ly, Sowath; Hul, Vibol; Deubel, Vincent; Morand, Serge; Buchy, Philippe

    2016-01-01

    Southeastern Asia is a recognised hotspot for emerging infectious diseases, many of which have an animal origin. Mammarenavirus infections contribute significantly to the human disease burden in both Africa and the Americas, but little data exists for Asia. To date only two mammarenaviruses, the widely spread lymphocytic choriomeningitis virus and the recently described Wēnzhōu virus have been identified in this region, but the zoonotic impact in Asia remains unknown. Here we report the presence of a novel mammarenavirus and of a genetic variant of the Wēnzhōu virus and provide evidence of mammarenavirus-associated human infection in Asia. The association of these viruses with widely distributed mammals of diverse species, commonly found in human dwellings and in peridomestic habitats, illustrates the potential for widespread zoonotic transmission and adds to the known aetiologies of infectious diseases for this region. PMID:27278118

  6. Evidence of human infection by a new mammarenavirus endemic to Southeastern Asia

    PubMed Central

    Blasdell, Kim R; Duong, Veasna; Eloit, Marc; Chretien, Fabrice; Ly, Sowath; Hul, Vibol; Deubel, Vincent; Morand, Serge; Buchy, Philippe

    2016-01-01

    Southeastern Asia is a recognised hotspot for emerging infectious diseases, many of which have an animal origin. Mammarenavirus infections contribute significantly to the human disease burden in both Africa and the Americas, but little data exists for Asia. To date only two mammarenaviruses, the widely spread lymphocytic choriomeningitis virus and the recently described Wēnzhōu virus have been identified in this region, but the zoonotic impact in Asia remains unknown. Here we report the presence of a novel mammarenavirus and of a genetic variant of the Wēnzhōu virus and provide evidence of mammarenavirus-associated human infection in Asia. The association of these viruses with widely distributed mammals of diverse species, commonly found in human dwellings and in peridomestic habitats, illustrates the potential for widespread zoonotic transmission and adds to the known aetiologies of infectious diseases for this region. DOI: http://dx.doi.org/10.7554/eLife.13135.001 PMID:27278118

  7. The phylogeography of Indoplanorbis exustus (Gastropoda: Planorbidae) in Asia

    PubMed Central

    2010-01-01

    Background The freshwater snail Indoplanorbis exustus is found across India, Southeast Asia, central Asia (Afghanistan), Arabia and Africa. Indoplanorbis is of economic importance in that it is responsible for the transmission of several species of the genus Schistosoma which infect cattle and cause reduced livestock productivity. The snail is also of medical importance as a source of cercarial dermatitis among rural workers, particularly in India. In spite of its long history and wide geographical range, it is thought that Indoplanorbis includes only a single species. The aims of the present study were to date the radiation of Indoplanorbis across Asia so that the factors involved in its dispersal in the region could be tested, to reveal potential historical biogeographical events shaping the phylogeny of the snail, and to look for signs that I. exustus might be polyphyletic. Results The results indicated a radiation beginning in the late Miocene with a divergence of an ancestral bulinine lineage into Assam and peninsular India clades. A Southeast Asian clade diverged from the peninsular India clade late-Pliocene; this clade then radiated at a much more rapid pace to colonize all of the sampled range of Indoplanorbis in the mid-Pleistocene. Conclusions The phylogenetic depth of divergences between the Indian clades and Southeast Asian clades, together with habitat and parasitological differences suggest that I. exustus may comprise more than one species. The timescale estimated for the radiation suggests that the dispersal to Arabia and to Southeast Asia was facilitated by palaeogeographical events and climate change, and did not require human involvement. Further samples from Afghanistan, Africa and western India are required to refine the phylogeographical hypothesis and to include the African Recent dispersal. PMID:20602771

  8. Measurements of the spin states of Europa and Ganymede

    NASA Astrophysics Data System (ADS)

    Margot, Jean-Luc; Padovan, S.; Campbell, D.; Peale, S.; Ghigo, F.

    2013-10-01

    Measuring the spin states of the Galilean satellites holds the key to fundamental interior and surface properties. First, the spin state can reveal the presence of a subsurface ocean: a decoupling between the icy shell and the interior results in a different spin signature than that of a solid body. Second, the value of the obliquity combined with the known gravitational harmonics can provide a direct measurement of the polar moment of inertia, a crucial constraint on interior models. Finally, the obliquity may explain remarkable surface features, such as the distribution and shape of cycloids on Europa, and the direction of strike-slip faults. Here we present the first direct observations of the spin axis orientations of Europa and Ganymede. We use the same Earth-based radar technique that provided measurements of Mercury's obliquity at the sub-arcminute level, observational evidence that the core is molten, and core size estimates [1,2]. The measurements make simultaneous use of the Goldstone Solar System Radar and the Green Bank Telescope located ~3200 km away. It is the correlation of radar echoes received at these two stations that yields superb leverage on the spin state of the illuminated body. Because the Galilean satellites are further away than Mercury, and because they spin faster than Mercury, the signal-to-noise ratio of the observations is reduced by a factor of ~3000. Nevertheless, the telltale correlations are clearly detected in our data. Using measurements at 13 epochs in 2011 and 4 epochs in 2012, we are able to pinpoint Europa's spin axis orientation with a precision of ~0.1 deg, and our result is inconsistent with theoretical or model-based estimates [3,4,5]. For Ganymede, we secured measurements at 3 epochs in 2011 and 2 epochs in 2012, and the larger signal-to-noise ratio results in a comparable precision for the spin axis orientation. References [1] J. L. Margot et al. Science, 316:710, 2007. [2] J. L. Margot et al. JGR (Planets), 117(E16

  9. Chaos on Europa: Transition from solid ice to slush

    NASA Astrophysics Data System (ADS)

    Collins, G. C.

    2011-12-01

    About a quarter of Jupiter's moon Europa is covered by patches of "chaotic" terrain where some parts of the preexisting surface have been disrupted into "plates" that are tilted and translated, and other parts have been replaced by an irregular hummocky matrix of jumbled ice blocks. Catastrophic ice-fluid interactions on the Earth offer attractive analogies to advance our understanding of the formation of chaotic terrain on Europa. The morphology of chaos terrain indicates a sharp change in mechanical properties between the undisrupted plates and the highly disrupted matrix. Where plates are locally higher than the matrix, the boundary is a steep cliff, but where the matrix is locally higher, the boundary is rounded like a viscous flow. This indicates that the plates are behaving as solid ice, while the adjacent matrix is behaving as a fluid. The horizontal translation and tilting of the solid ice plates indicates that the material beneath them must also be acting as a fluid. The transition from solid ice to slushy matrix is not always accompanied by horizontal motion; for example background ridges can be continuously traced over large areas of chaos matrix in Thrace Macula. In some areas, the boundary between plates and matrix appears to be controlled by the existence of prominent ridges, but the matrix may either go around the ridge, or be contained entirely within the outline of the ridge. Perhaps fractures associated with preexisting ridges affect the subsurface flow of liquid within the ice shell, and control the transition between solid ice and slush. In color and spectroscopic data, chaos matrix is accompanied by an unknown dark substance, which could include hydrated salts or sulfuric acid (Carlson et al. 2009). Dark material can also be found separate from the matrix, in topographically low areas immediately surrounding chaos terrain. After chaos formation, the matrix may still exhibit mechanical properties different from the surrounding ice, as evidenced

  10. Europa 'Ice Rafts' in local and color context

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This image of Jupiter's icy satellite Europa shows surface features such as domes and ridges, as well as a region of disrupted terrain including crustal plates which are thought to have broken apart and 'rafted' into new positions. The image covers an area of Europa's surface about 250 by 200 kilometer (km) and is centered at 10 degrees latitude, 271 degrees longitude. The color information allows the surface to be divided into three distinct spectral units. The bright white areas are ejecta rays from the relatively young crater Pwyll, which is located about 1000 km to the south (bottom) of this image. These patchy deposits appear to be superposed on other areas of the surface, and thus are thought to be the youngest features present. Also visible are reddish areas which correspond to locations where non-ice components are present. This coloring can be seen along the ridges, in the region of disrupted terrain in the center of the image, and near the dome-like features where the surface may have been thermally altered. Thus, areas associated with internal geologic activity appear reddish. The third distinct color unit is bright blue, and corresponds to the relatively old icy plains.

    This product combines data taken by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft during three separate flybys of Europa. Low resolution color data (violet, green, and 1 micron) acquired in September 1996 were combined with medium resolution images from December 1996, to produce synthetic color images. These were then combined with a high resolution mosaic of images acquired in February 1997.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http

  11. Salts on Europa's surface detected by Galileo's near infrared mapping spectrometer

    USGS Publications Warehouse

    McCord, T.B.; Hansen, G.B.; Fanale, F.P.; Carlson, R.W.; Matson, D.L.; Johnson, T.V.; Smythe, W.D.; Crowley, J.K.; Martin, P.D.; Ocampo, A.; Hibbitts, C.A.; Granahan, J.C.

    1998-01-01

    Reflectance spectra in the 1- to 2.5-micrometer wavelength region of the surface of Europa obtained by Galileo's Near Infrared Mapping Spectrometer exhibit distorted water absorption bands that indicate the presence of hydrated minerals. The laboratory spectra of hydrated salt minerals such as magnesium sulfates and sodium carbonates and mixtures of these minerals provide a close match to the Europa spectra. The distorted bands are only observed in the optically darker areas of Europa, including the lineaments, and may represent evaporite deposits formed by water, rich in dissolved salts, reaching the surface from a water-rich layer underlying an ice crust.

  12. Ion Irradiation of Sulfuric Acid: Implications for its Stability on Europa

    NASA Technical Reports Server (NTRS)

    Loeffler, M. J.; Hudson, R. L.; Moore, M. H.

    2010-01-01

    The Galileo near-infrared mapping spectrometer (NIMS) detected regions on Europa's surface containing distorted H2O bands. This distortion likely indicates that there are other molecules mixed with the water ice. Based on spectral comparison, some of the leading possibilities are sulfuric acid, salts. or possibly H3O(+). Previous laboratory studies have shown that sulfuric acid can be created by irradiation of H2OSO2 mixtures, and both molecules are present on Europa. In this project, we were interested in investigating the radiation stability of sulfuric acid (H2SO4) and determining its lifetime on the surface of Europa.

  13. The Search for a Habitable Europa: Radar, Water and an Active Ice Shell

    NASA Astrophysics Data System (ADS)

    Blankenship, D. D.; Schmidt, B. E.; Young, D. A.; Schroeder, D. M.; Greenbaum, J. S.

    2011-10-01

    Future Europa exploration will seek to characterize the distribution of shallow subsurface water as well as to understand the formation of surface features through dynamic ice-shell processes. Radar sounding will be a critical tool for detecting these features, and should be of primary interest to the astrobiology community for understanding how and where life might arise on Europa. To develop successful instrumentation and data interpretation techniques for exploring Europa, we must leverage analogous terrestrial environments and processes. Airborne ice penetrating radar is now a mature tool in terrestrial studies of Earth's ice sheets, and orbital examples have been successful at the Moon and Mars.

  14. Biomass-burning Aerosols in South East-Asia: Smoke Impact Assessment(BASE-ASIA)

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee; Hsu, Christina N.; King, Michael D.; Shu, Peter K.

    2002-01-01

    Biomass burning has been a regular practice for land clearing and land conversion in many countries, especially in Africa, South America, and South East Asia. Significant global sources of greenhouse gases (e.g., CO2, CH4), chemically active gases (e.g., NO, CO, HC, CH3Br), and atmospheric aerosols are produced by biomass-burning processes, which influence the Earth-atmosphere energetics and hence impact both global climate and tropospheric chemistry. Some gases and aerosols can serve as active cloud condensation nuclei, which play important role in determining the net radiation budget, precipitation rate, and cloud lifetime. Biomass burning also affects the biogeochemical cycling of nitrogen and carbon compounds from the soil to the atmosphere; the hydrological cycle (i.e., run off and evaporation); the reflectivity and emissivity of the land; and the stability of ecosystems and ecosystem biodiversity. Compared to Africa and South America, the climatology in South East Asia reveals quite different characteristics, showing distinct large-scale smoke and cloud sources and interaction regimes. The fresh water distribution in this region is highly dependent on monsoon rainfall; in fact, the predictability of the tropical climate system is much reduced during the boreal spring, which is associated with the peak season of biomass burning activities. Estimating the burning fuel (e.g., bark, branches, and wood), an important part of studying regional carbon cycle, may rely on utilizing a wide range of distinctive spectral features in the shortwave and longwave regions. Therefore, to accurately assess the impact of smoke aerosols in this region requires continuous observations from satellites, aircraft, networks of ground-based instruments and dedicated field experiments. A new initiative will be proposed and discussed.

  15. Natives or immigrants: modern human origin in east Asia.

    PubMed

    Jin, L; Su, B

    2000-11-01

    East Asia is one of the few regions in the world where a relatively large number of human fossils have been unearthed--a discovery that has been taken as evidence for an independent local origin of modern humans outside of Africa. However, genetic studies conducted in the past ten years, especially using Y chromosomes, have provided unequivocal evidence for an African origin of East Asian populations. The genetic signatures present in diverse East Asian populations mark the footsteps of prehistoric migrations that occurred tens of thousands of years ago. PMID:11253652

  16. The Tectonic Evolution of Asia

    NASA Astrophysics Data System (ADS)

    Lee, Tung-Yi

    Asia is the youngest continent on our planet and has been assembled largely over the past 400 m.y. In the past decade, following rapid developments on the economic front and political transformations in Asia, Earth science research has continuously become more important for both natural resources evaluation and hazards reduction. Consequently, more and more attempts have been focused on Asia in order to understand this complex region. The more the geoscience community works in this region, however, the more we realize our insufficient knowledge of the largest continent on Earth. This problem is not only caused by the region's inaccessibility, but also by cultural and political barriers.

  17. Seismic Investigations of Europa and Other Ocean Worlds

    NASA Astrophysics Data System (ADS)

    Vance, Steve; Tsai, Victor; Kedar, Sharon; Bills, Bruce; Castillo-Rogez, Julie; Jackson, Jennifer

    2016-04-01

    Seismic investigations offer the most comprehensive view into the deep interiors of planetary bodies. Developing missions (InSight, Europa Lander, Lunar Geophysical Network) identify seismology as a critical measurement to constrain interior structure and thermal state. In oceanic icy worlds, pinpointing the radial depths of compositional interfaces using seismology in a broad frequency range can address uncertainty in interior structures inferred from gravity and magnetometry studies, such as those planned for NASA's Europa and ESA's JUICE missions. Seismology also offers information about fluid motions within or beneath ice, which complement magnetic studies; and can record the dynamics of ice layers, which would reveal mechanisms and spatiotemporal occurrence of crack formation and propagation. Investigating these with future missions will require detailed modeling of seismic sources and signatures in order to develop the most suitable instrumentation. We evaluate seismic sources and their propagation in Europa, with extension to other oceanic icy worlds, building on prior studies (Kovach and Chyba 2001, Lee et al. 2003, Cammarano et al. 2006, Panning et al. 2006, Leighton et al. 2008). We also consider additional sources: gravitationally forced librations, which will create volume-filling turbulent flow (le Bars et al. 2015), a possible seismic source similar to that seen from turbulent flow in terrestrial rivers (Tsai et al., 2012; Gimbert et al., 2014; Chao et al., 2015); downflow of dense brines from chaos regions on Europa into its underlying ocean (Sotin et al. 2002), possibly resembling riverine flows and flows through glacial channels (Tsai and Rice 2012); ocean acoustic signals that couple with the overlying ice to produce seismic waves, by analogy with Earth's ocean-generated seismic hum (Kedar 2011, Ardhuin 2015). Ardhuin, F., Gualtieri, L., and Stutzmann, E. (2015). GRL., 42. Cammarano, F., Lekic, V., Manga, M., Panning, M., and Romanowicz, B. (2006

  18. The Radial Dependence of Tidal Deformation in Europa's Ice

    NASA Astrophysics Data System (ADS)

    Walker, M.; Bills, B. G.; Mitchell, J.

    2013-12-01

    We present results of an elastic-gravitational stress-strain model, used to examine the spatial and temporal patterns of tidal stress, both at the surface and within the ice shell of Europa. By computing the tidal displacements in an elastic ice shell floating on a liquid water ocean and using a range of current and past projected orbital and rotational parameters, we examine the magnitudes and orientations of the tidal stress tensors on a grid of locations throughout Europa's ice shell and time. Preliminary results indicate elastic Love numbers for Europa, with a 20km ice shell, of (h2=1.20, l2=0.32, k2=0.24). These numbers agree well with surface results from previously published deformation models. Probing the interior of the ice shell, we find that the presence of a sub-surface fluid layer significantly increases both radial and tangential components of displacement within the shell, compared to a completely solid system. Furthermore, within the shell both components of displacement peak at the shell base and decrease towards the surface. Correspondingly, normal stress decreases with radius. We have also found that, as expected, shear stresses peak at the mid-plane of the shell. Importantly, it should be noted that as opposed to the outer surface, which is void of radial tractions, the interior of the shell exhibits the full stress tensor. The complex network of linear fractures on Europa's surface is a record of the satellite's history of tectonic processing. These fractures are interpreted as material failure due to a time varying tidal stress field. Most tidal fracture models focus on propagation of existing features at the surface. One goal of our study is to compare stress conditions at depth, within the shell, to those at the surface. Due to vanishing shear stress, at the top and bottom of the shell, we expect maximum deviatoric stress to occur near its mid-plane. With an appropriate failure criterion, knowledge of the true location of maximum stress will

  19. The evil twin of Agenor: tectonic convergence on Europa

    NASA Astrophysics Data System (ADS)

    Greenberg, Richard

    2004-02-01

    The dilemma of the surface-area budget on Europa is resolved by identification of sites of crustal convergence, which have balanced the continual and common creation of new surface along dilational bands and pull-aparts. Convergence bands are characterized by a distinctive, albeit subdued, morphology. The prominent, unusual lineament Agenor is one of several examples. We also find diametrically opposite Agenor a similar bright linear feature surrounded by markings that allow reconstruction, which shows it to be a convergence feature. Until recently, identification of convergence sites was difficult because these features are subtle and do not exhibit structures (like the Himalayas or plate subduction) familiar from convergence of thick solid crusts on terrestrial planets.

  20. Evidence for sulphur implantation in Europa's UV absorption band

    NASA Technical Reports Server (NTRS)

    Lane, A. L.; Nelson, R. M.; Matson, D. L.

    1981-01-01

    The UV spectral characteristics of the Galilean satellites are investigated (using data from the International Ultraviolet Explorer (IUE) spacecraft) as a function of the orbital position, large-scale areal variability, and temporal dynamics. The discovery of an absorption feature at 280 nm in Europa's reflection spectrum is reported and observations show that the absorption is strongest on the trailing hemisphere (central longitude 270 degrees). The feature resembles SO2 and seems to result from S-O bond formation between deeply implanted sulphur atoms and the adjacent damaged water-ice-lattice. The sulphur supposedly comes from energetic (hundreds of keV) sulphur ions that are present in the Jovian magnetosphere. An appropriate equilibrium condition can be found to match the observed spectral data if sputtering erosion occurs at no greater than approximately 20 meters per one billion years.

  1. Galileo's Multiinstrument Spectral View of Europa's Surface Composition

    NASA Astrophysics Data System (ADS)

    Fanale, Fraser P.; Granahan, James C.; McCord, Thomas B.; Hansen, Gary; Hibbitts, Charles A.; Carlson, Robert; Matson, Dennis; Ocampo, Adriana; Kamp, Lucas; Smythe, William; Leader, Frank; Mehlman, Robert; Greeley, Ronald; Sullivan, Robert; Geissler, Paul; Barth, Charles; Hendrix, Amanda; Clark, Beth; Helfenstein, Paul; Veverka, Joseph; Belton, Michael J. S.; Becker, Kris; Becker, Tammy; Galileo NIMS, SSI, UVS instrument Teams

    1999-06-01

    We have combined spectral reflectance data from the Solid State Imaging (SSI) experiment, the Near-Infrared Mapping Spectrometer (NIMS), and the Ultraviolet Spectrometer (UVS) in an attempt to determine the composition and implied genesis of non-H2O components in the optical surface of Europa. We have considered four terrains: (1) the "dark terrains" on the trailing hemisphere, (2) the "mottled terrain," (3) the linea on the leading hemisphere, and (4) the linea embedded in the dark terrain on the trailing hemisphere. The darker materials in these terrains exhibit remarkably similar spectra in both the visible and near infrared. In the visible, a downturn toward shorter wavelengths has been attributed to sulfur. The broad concentrations of dark material on the trailing hemisphere was originally thought to be indicative of exogenic sulfur implantation. While an exogenic cause is still probable, more recent observations by the UVS team at higher spatial resolution have led to their suggestions that the role of the bombardment may have primarily been to sputter away overlying ice and to reveal underlying endogenic non-H2O contaminants. If so, this might explain why the spectra in all these terrains are so similar despite the fact that the contaminants in the linea are clearly endogenic and those in the mottled terrain are almost certainly so. In the near infrared, all these terrains exhibit much more asymmetrical bands at 1.4 and 2.0 μm at shorter wavelengths than spectra from elsewhere on Europa. It has been argued that this is because the water molecules are bound in hydrated salts. However, this interpretation has been challenged and it has also been argued that pure coarse ice can exhibit such asymmetric bands under certain conditions. The nature of this controversy is briefly discussed, as are theoretical and experimental studies bearing on this problem.

  2. Geology and Origin of Europa's Mitten Feature (Murias Chaos)

    NASA Technical Reports Server (NTRS)

    Figueredo, P. H.; Chuang, F. C.; Rathbun, J.; Kirk, R. L.; Greeley, R.

    2002-01-01

    The "Mitten" (provisionally named Murias Chaos by the International Astronomical Union) is a region of elevated chaos-like terrain in the leading hemisphere of Europa. Its origin had been explained under the currently debated theories of melting through a thin lithosphere or convection within a thick one. Galileo observations reveal several characteristics that suggest that the Mitten is distinct from typical chaos terrain and point to a different formational process. Photoclinometric elevation estimates suggest that the Mitten is slightly elevated with respect to the surrounding terrain; geologic relations indicate that it must have raised significantly from the plains in its past, resembling disrupted domes on Europa's trailing hemisphere. Moreover, the Mitten material appears to have extruded onto the plains and flowed for tens of kilometers. The area subsequently subsided as a result of isostatic adjustment, viscous relaxation, and/or plains loading. Using plate flexure models, we estimated the elastic lithosphere in the area to be several kilometers thick. We propose that the Mitten originated by the ascent and extrusion of a large thermal diapir. Thermal-mechanical modeling shows that a Mitten-sized plume would remain sufficiently warm and buoyant to pierce through the crust and flow unconfined on the surface. Such a diapir probably had an initial radius between 5 and 8 km and an initial depth of 20-40 km, consistent with a thick-lithosphere model. In this scenario the Mitten appears to represent the surface expression of the rare ascent of a large diapir, in contrast to lenticulae and chaos terrain, which may form by isolated and clustered small diapirs, respectively.

  3. Galileo's Multiinstrument Spectral View of Europa's Surface Composition

    USGS Publications Warehouse

    Fanale, F.P.; Granahan, J.C.; McCord, T.B.; Hansen, G.; Hibbitts, C.A.; Carlson, R.; Matson, D.; Ocampo, A.; Kamp, L.; Smythe, W.; Leader, F.; Mehlman, R.; Greeley, R.; Sullivan, R.; Geissler, P.; Barth, C.; Hendrix, A.; Clark, B.; Helfenstein, P.; Veverka, J.; Belton, M.J.S.; Becker, K.; Becker, T.

    1999-01-01

    We have combined spectral reflectance data from the Solid State Imaging (SSI) experiment, the Near-Infrared Mapping Spectrometer (NIMS), and the Ultraviolet Spectrometer (UVS) in an attempt to determine the composition and implied genesis of non-H2O components in the optical surface of Europa. We have considered four terrains: (1) the "dark terrains" on the trailing hemisphere, (2) the "mottled terrain," (3) the linea on the leading hemisphere, and (4) the linea embedded in the dark terrain on the trailing hemisphere. The darker materials in these terrains exhibit remarkably similar spectra in both the visible and near infrared. In the visible, a downturn toward shorter wavelengths has been attributed to sulfur. The broad concentrations of dark material on the trailing hemisphere was originally thought to be indicative of exogenic sulfur implantation. While an exogenic cause is still probable, more recent observations by the UVS team at higher spatial resolution have led to their suggestions that the role of the bombardment may have primarily been to sputter away overlying ice and to reveal underlying endogenic non-H2O contaminants. If so, this might explain why the spectra in all these terrains are so similar despite the fact that the contaminants in the linea are clearly endogenic and those in the mottled terrain are almost certainly so. In the near infrared, all these terrains exhibit much more asymmetrical bands at 1.4 and 2.0 ??m at shorter wavelengths than spectra from elsewhere on Europa. It has been argued that this is because the water molecules are bound in hydrated salts. However, this interpretation has been challenged and it has also been argued that pure coarse ice can exhibit such asymmetric bands under certain conditions. The nature of this controversy is briefly discussed, as are theoretical and experimental studies bearing on this problem. ?? 1999 Academic Press.

  4. Geology and origin of Europa's "Mitten" feature (Murias Chaos)

    USGS Publications Warehouse

    Figueredo, P.H.; Chuang, F.C.; Rathbun, J.; Kirk, R.L.; Greeley, R.

    2002-01-01

    The "Mitten" (provisionally named Murias Chaos by the International Astronomical Union) is a region of elevated chaos-like terrain in the leading hemisphere of Europa. Its origin had been explained under the currently debated theories of melting through a thin lithosphere or convection within a thick one. Galileo observations reveal several characteristics that suggest that the Mitten is distinct from typical chaos terrain and point to a different formational process. Photoclinometric elevation estimates suggest that the Mitten is slightly elevated with respect to the surrounding terrain; geologic relations indicate that it must have raised significantly from the plains in its past, resembling disrupted domes on Europa's trailing hemisphere. Moreover, the Mitten material appears to have extruded onto the plains and flowed for tens of kilometers. The area subsequently subsided as a result of isostatic adjustment, viscous relaxation, and/or plains loading. Using plate flexure models, we estimated the elastic lithosphere in the area to be several kilometers thick. We propose that the Mitten originated by the ascent and extrusion of a large thermal diapir. Thermal-mechanical modeling shows that a Mitten-sized plume would remain sufficiently warm and buoyant to pierce through the crust and flow unconfined on the surface. Such a diapir probably had an initial radius between 5 and 8 km and an initial depth of 20-40 km, consistent with a thick-lithosphere model. In this scenario the Mitten appears to represent the surface expression of the rare ascent of a large diapir, in contrast to lenticulae and chaos terrain, which may form by isolated and clustered small diapirs, respectively.

  5. Emplacement of Volcanic Domes on Venus and Europa

    NASA Technical Reports Server (NTRS)

    Quick, Lynnae C.; Glaze, Lori S.; Baloga, Steve M.

    2015-01-01

    Placing firmer constraints on the emplacement timescales of visible volcanic features is essential to obtaining a better understanding of the resurfacing history of Venus. Fig. 1 shows a Magellan radar image and topography for a putative venusian lava dome. 175 such domes have been identified, having diameters that range from 19 - 94 km, and estimated thicknesses as great as 4 km [1-2]. These domes are thought to be volcanic in origin [3], having formed by the flow of a viscous fluid (i.e., lava) onto the surface. Among the unanswered questions surrounding the formation of Venus steep-sided domes are their emplacement duration, composition, and the rheology of the lava. Rheologically speaking, maintenance of extremely thick, 1-4 km flows necessitates higher viscosity lavas, while the domes' smooth upper surfaces imply the presence of lower viscosity lavas [2-3]. Further, numerous quantitative issues, such as the nature and duration of lava supply, how long the conduit remained open and capable of supplying lava, the volumetric flow rate, and the role of rigid crust in influencing flow and final morphology all have implications for subsurface magma ascent and local surface stress conditions. The surface of Jupiter's icy moon Europa exhibits many putative cryovolcanic constructs [5-7], and previous workers have suggested that domical positive relief features imaged by the Galileo spacecraft may be volcanic in origin [5,7-8] (Fig. 2). Though often smaller than Venus domes, if emplaced as a viscous fluid, formation mechanisms for europan domes may be similar to those of venusian domes [7]. Models for the emplacement of venusian lava domes (e.g. [9-10]) have been previously applied to the formation of putative cryolava domes on Europa [7].

  6. Physical electron belt model from Jupiter surface out to Europa

    NASA Astrophysics Data System (ADS)

    Sicard, A.; Bourdarie, S.

    2003-04-01

    The three dimensional model, Salammbo-3D, has been developed to study spatial distribution of electron in the inner radiation belts of Jupiter. In a first time, this model was valid between L = 1 and L = 6, just inside Io orbit. Now, it has been extended up to L = 9.5, just inside Europa orbit. To allow this extension, a more realistic magnetic field than the tilted dipole magnetic field, used before, has been introduced. Two magnetic field models are available: the model of Connerney (1981) and the one of Khurana (1997). Both of them are composed of two parts: an internal magnetic field (derivable of a scalar potential) and a external magnetic field (due to the current sheet). Results deduced from Salammbo-3D, using these two different models, will be shown and compared. Two important results come out from this study. Firstly, the extension of our model outside Io orbit aims to show that Io do not play any role on relativistic electron dynamics i.e. it do not create losses of particles like Amalthea, Thebe and first two moons. The second important result is that external field, due to current sheet, only change radiation belts topology for L > 5. Then, to validate our 3D code from the Jovian surface up to Europa orbit, the results will be compared with two kinds of observations. A first comparison will be done with spacecraft data (Pioneer 10 and 11) and a second with radio observation (VLA). Indeed, with the help of Salammbo-3D and a synchrotron emission model, in situ 2D images of Jupiter synchrotron emission can be deduced. It is then possible to investigate on the global radiation belts shape by comparing simulations and VLA observations.

  7. Multistage evolution and variable motion history of Agenor Linea, Europa

    NASA Astrophysics Data System (ADS)

    Hoyer, Lauren; Kattenhorn, Simon A.; Watkeys, Michael K.

    2014-04-01

    Europa, the second Galilean moon of Jupiter, is composed of a silicate mantle and an ice shell which overlies a supposed subsurface ocean. The surface of Europa is scarred with fractures varying in morphology, dimensions, and geometry. We focus on Agenor Linea: a ∼1500 km bright band that extends across Europa’s antijovian to trailing southern hemisphere. Agenor Linea is morphologically a band-like strike-slip fault; however, it experienced at least three evolutionary growth phases marked by three zones of varying albedo, each with a different geological history. Structures within the band material and kinematic indicators are consistent with formation through oblique left-lateral dilation, followed by normal dilation and right-lateral strike-slip movement, or combinations thereof. These motions produced a cumulative maximum right-lateral offset of 29.5 km and a maximum band width of 34 km. We interpret Agenor Linea to have formed primarily in response to the combined effects of nonsynchronous rotation stress and diurnal tidal flexing. If so, its orientation is optimal for right-lateral oblique opening in the current global stress field, consistent with its most recent kinematic behavior. A small amount of offset of relatively young tension fractures that postdate cryospheric disruption by lenticulae suggest the possibility of ongoing activity along Agenor. In contrast to a previously published model in which strike-slip duplexing was the primary process of band formation, this study shows that initial dilation of three distinct morphological zones under disparate stress orientations preceded strike-slip motion that resulted in both localized and distributed deformation features within the zones across the width of the band.

  8. Mapping the Ice Depth of Europa with Ultrahigh Energy Particles

    NASA Astrophysics Data System (ADS)

    Romero-Wolf, A.; Naudet, C. J.

    2012-12-01

    There has been recent interest in applying radio emission of ultra-high energy neutrinos interacting in the ice of Europa. The idea was first described by Gorham (2004)[1] in the context of ultra-high energy particle detection. Shoji, Kurita, and Tanaka (2011)[2] proposed a technique for measuring ice depth using the radio intensity distribution of radio impulses emitted by interactions deep in the Europan ice. Miller, Schaefer, and Sequeira (2012)[3] follow up this study with a simulation of a radio detector mission to constrain the ice depth of Europa. The radio signal results from an effect proposed by Askar'yan (1962)[4] where the particle shower induced by the neutrino interaction accumulates a charge excess traveling faster than the speed of light in the medium and produces a coherent Cherenkov pulse at radio frequencies. We evaluate the feasibility of such a mission given the current state of knowledge of ultra-high energy particle detection and radio pulse production. References [1] Gorham (2004), Planet-sized Detectors for Ultra-high Energy Neutrinos & Cosmic Rays, NASA Advanced Planning Office's Capability Roadmap Public Workshop, Nov. 30, 2004, astro-ph/0411510 [2] Shoji, Kurita, and Tanaka (2011), Constraint of Europan ice thickness by measuring electromagnetic emissions induced by neutrino interaction, Geophysical Research Letters, 38, L08202 [3] Miller, Shaefer, Sequeira, PRIDE (Passive Radio [frequency] Ice Depth Experiment): An instrument to passively measure ice depth from a Europan orbiter using neutrinos, Icarus 220 877-888 [4] Askar'yan (1962), Excess negative charge of an electron photon shower and its coherent radiation originating from it. Radio recording of showers under the ground and on the Moon, Sov. Phys. JETP, 14, 441-443.

  9. Tidal Love numbers of membrane worlds: Europa, Titan, and Co.

    NASA Astrophysics Data System (ADS)

    Beuthe, Mikael

    2015-09-01

    Under tidal forcing, icy satellites with subsurface oceans deform as if the surface were a membrane stretched around a fluid layer. 'Membrane worlds' is thus a fitting name for these bodies and membrane theory provides the perfect toolbox to predict tidal effects. I describe here a new membrane approach to tidal perturbations based on the general theory of viscoelastic-gravitational deformations of spherically symmetric bodies. The massive membrane approach leads to explicit formulas for viscoelastic tidal Love numbers which are exact in the limit of zero crust thickness. Formulas for load Love numbers come as a bonus. The accuracy on k2 and h2 is better than one percent if the crust thickness is less than five percents of the surface radius, which is probably the case for Europa and Titan. The new approach allows for density differences between crust and ocean and correctly includes crust compressibility. This last feature makes it more accurate than the incompressible propagator matrix method. Membrane formulas factorize shallow and deep interior contributions, the latter affecting Love numbers mainly through density stratification. I show that a screening effect explains why ocean stratification typically increases Love numbers instead of reducing them. For Titan, a thin and dense liquid layer at the bottom of a light ocean can raise k2 by more than ten percents. The membrane approach can also deal with dynamical tides in a non-rotating body. I show that a dynamical resonance significantly decreases the tilt factor and may thus lead to underestimating Europa's crust thickness. Finally, the dynamical resonance increases tidal deformations and tidal heating in the crust if the ocean thickness is of the order of a few hundred meters.

  10. Lake Vostok: An earthly analogue for the geomicrobiology on Europa

    NASA Astrophysics Data System (ADS)

    Priscu, J. C.; Christner, B. C.

    2007-12-01

    The recent discovery of more than 150 subglacial lakes beneath the Antarctic ice sheet has important implications in our search for liquid water and associated life on other icy worlds. The largest of these lakes is Lake Vostok, which has a surface area of 14000 square km and a depth of 1000 m, making it one of the largest lakes on Earth. Although we have yet to sample directly the liquid water from any of the Antarctic subglacial lakes, refrozen lakewater (accretion ice) has been sampled just above the surface of Lake Vostok. Genomic and geochemical analysis of this ice reveals that the surface lake water supports a microbial assemblage with a density approaching 1000 cells per milliliter. Sequencing and phylogenetic analysis of the 900 to 1000 base pair small subunit rRNA gene sequences obtained revealed a low diversity of clones that classify within the beta, gamma and delta subdivisions of the phylum Proteobacteria. Nearest phylogenetic neighbor analysis of these gene sequences imply that the lake contains an aerobic and anaerobic consortium of bacteria with metabolisms dedicated to iron and sulfur respiration or oxidation indicating that these metals play a role in the bioenergetics of microorganisms that occur in Lake Vostok. Sequence analysis further revealed that heterotrophic life in the lake can be sustained by chemolithotrophic production of new carbon supplemented by dissolved organic carbon released from the overlying ice sheet. Data obtained from orbiters have revealed that a deep ocean of liquid water lies under a thick chaotic ice cover on Europa where organic matter derived from comets and oxidants provided by radiation from Jupiter's magnetosphere may provide a habitat for life and a reservoir of endogenous and exogenous substances much like we observe in Lake Vostok. Future studies of Antarctic subglacial lake environments will play a crucial role in our understanding of life on Europa and other frozen worlds.

  11. Biosignature detection at an Arctic analog to Europa.

    PubMed

    Gleeson, Damhnait F; Pappalardo, R T; Anderson, M S; Grasby, S E; Mielke, R E; Wright, K E; Templeton, A S

    2012-02-01

    The compelling evidence for an ocean beneath the ice shell of Europa makes it a high priority for astrobiological investigations. Future missions to the icy surface of this moon will query the plausibly sulfur-rich materials for potential indications of the presence of life carried to the surface by mobile ice or partial melt. However, the potential for generation and preservation of biosignatures under cold, sulfur-rich conditions has not previously been investigated, as there have not been suitable environments on Earth to study. Here, we describe the characterization of a range of biosignatures within potentially analogous sulfur deposits from the surface of an Arctic glacier at Borup Fiord Pass to evaluate whether evidence for microbial activities is produced and preserved within these deposits. Optical and electron microscopy revealed microorganisms and extracellular materials. Elemental sulfur (S⁰), the dominant mineralogy within field samples, is present as rhombic and needle-shaped mineral grains and spherical mineral aggregates, commonly observed in association with extracellular polymeric substances. Orthorhombic α-sulfur represents the stable form of S⁰, whereas the monoclinic (needle-shaped) γ-sulfur form rosickyite is metastable and has previously been associated with sulfide-oxidizing microbial communities. Scanning transmission electron microscopy showed mineral deposition on cellular and extracellular materials in the form of submicron-sized, needle-shaped crystals. X-ray diffraction measurements supply supporting evidence for the presence of a minor component of rosickyite. Infrared spectroscopy revealed parts-per-million level organics in the Borup sulfur deposits and organic functional groups diagnostic of biomolecules such as proteins and fatty acids. Organic components are below the detection limit for Raman spectra, which were dominated by sulfur peaks. These combined investigations indicate that sulfur mineral deposits may contain

  12. Photochemistry-emission coupled model for Europa and Ganymede

    NASA Astrophysics Data System (ADS)

    Cessateur, Gaël; Barthelemy, Mathieu; Peinke, Isabel

    2016-03-01

    In the frame of the JUICE mission, preliminary studies of the Jupiter's icy moons, such as Ganymede and Europa, are mandatory. The present paper aims at characterizing the impact of the solar UV flux and its variability on their atmospheres. The solar UV radiation is responsible for the photoionization, photodissociation, and photoexcitation processes within planetary atmospheres. A 1-D photoabsorption model has been developed for different observational geometries, on the basis of a neutral atmospheric model. Considering various production and loss mechanisms but also the transport of oxygen atoms, we estimate the red and green line emissions from photo impact-induced excitation only. These dayglow emissions can represent few percent of the global airglow emission, mainly dominated by electron-induced excitation in auroral regions. For limb viewing conditions, red line emission is bright enough to be detected from actual spectrometers, from 338 R to 408 R according to the solar activity. This is also the case for the green line with 8 R at limb viewing. Considering a different neutral atmosphere model, with an O2 column density 50% more important, leads to a 14% increase in the red line emissions for limb viewing close to the surface. This difference could be important enough to infer which neutral model is the most likely. However, uncertainties on the solar UV flux might also prevent to constrain the O2 column density when using ground-based observations in the visible only. The impact of solar flares on the red line emissions for Europa has also been investigated within a planetary space weather context.

  13. A Compositional Map of the Tyre Region of Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This composite image of part of the Jupiter moon, Europa, shows the distribution of ice and minerals for the structure named Tyre. The image was created with data from Galileo's Solid State Imaging (SSI) camera and the Near Infrared Mapping Spectrometer (NIMS). Tyre, the circular feature, is 140 kilometers in diameter (about the size of the island of Hawaii) and is thought to be the site where an asteroid or comet impacted Europa's ice crust. The blue in this image indicates areas with higher concentrations of mineral salts. These salts are similar in composition to those found in the bottom of Death Valley, California. The yellow-orange regions are areas that have a high surface abundance of water ice. The center of this impact feature (located at 34 degrees latitude and 146.5 degrees longitude) appears to have a surface composed of coarse-grained ice. This composite image is approximately 214 kilometers wide and is the product of a SSI image of 595 meters per picture element and a NIMS 6.26 kilometer per picture element observation. The SSI image and NIMS data were obtained on April 4, 1997 at ranges of 703,776 and 688,737 kilometers respectively. This image is projected like a map where north is up and is illuminated by sunlight coming from the west.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  14. High Resolution Mosaic of Ridges, Plains, and Mountains on Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This mosaic shows some of the highest resolution images obtained by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft during its eleventh orbit around Jupiter. North is to the top of the image. The sun illuminates the scene from the left, showing hundreds of ridges that cut across each other, indicating multiple episodes of ridge formation either by volcanic or tectonic activity within the ice. Also visible in the image are numerous isolated mountains or 'massifs'. The highest of these, located in the upper right corner and lower center of the mosaic, are approximately 500 meters (1,640 feet) high. Irregularly shaped areas where the ice surface appears to be lower than the surrounding plains (e.g., in the left-center and lower left corner of the mosaic) may be related to the 'chaos' areas of iceberg-like features seen in earlier SSI images of Europa.

    The mosaic, centered at 35.4 degrees north latitude and 86.8 degrees west longitude, covers an area of 108 kilometers by 90 kilometers (66 miles by 55 miles). The smallest distinguishable features in the image are about 68 meters (223 feet) across. These images were obtained on November 6, 1997, when the Galileo spacecraft was approximately 3,250 kilometers (1,983 miles) from Europa.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. JPL is a division of California Institute of Technology.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  15. Why Aren't All Ridges on Europa Cycloidal?

    NASA Astrophysics Data System (ADS)

    Kattenhorn, Simon A.; Hurford, T. A.

    2008-09-01

    Europa's arcuate cycloidal ridges formed in response to the rotating diurnal tidal stress field. However, most ridges are not cycloidal but are linear over great distances (>100s of km). Their orientations adequately fit a global stress field induced by a few degrees of nonsynchronous rotation (NSR) superimposed on the diurnal field, but only at the point in the orbit when tensile stress is maximized. At other times, linear ridges do not fit the pattern of stresses, unlike cycloids, which grow throughout a good portion of an orbit and are therefore very curved. Why does the ever-present diurnal stress field only sometimes dominate, creating cycloids? When do linear ridges grow? Was there an "age of cycloids” that heralded a fundamental change in europan tectonics, or simply a temporal oscillation between the two crack styles? We consider the relative merits of scenarios in which linear ridges: (1) only grow when stresses are maximized in the orbit, lengthening incrementally over time; (2) develop almost instantaneously by dynamic growth during a "snapshot in time” stress field; or (3) form when some other source of global stress temporarily drowns out diurnal stresses. Scenario (3) is considered most likely. A temporally variable global stress history, perhaps related to ice shell thickness variability, may have controlled crack growth style. Linear ridges dominated whenever the NSR stress exceeded some threshold level. Early in Europa's history, a thinner ice shell may have been associated with a faster NSR rate, allowing NSR stresses to consistently overwhelm the diurnal component, suppressing the formation of cycloids. As the shell thickened, NSR stress accumulation slowed. Linear ridge growth episodes relieved NSR stress, creating periods (perhaps many 1000s of years in duration) during which diurnal stresses dominated, conducive to cycloid development. Hence, there was overlap in the timing of cycloidal and linear ridge development.

  16. Wireline deep drill for exploration of Mars, Europa, and Enceladus

    NASA Astrophysics Data System (ADS)

    Zacny, K.; Paulsen, G.; Bar-Cohen, Y.; Beegle, L.; Sherrit, S.; Badescu, M.; Mellerowicz, B.; Rzepiejewska, O.; Craft, J.; Sadick, S.; Corsetti, F.; Ibarra, Y.; Bao, Xiaoqi; Lee, Hyeone Jae; Abbey, B.

    One of the most pressing current questions in space science is whether life has ever arisen anywhere else in the universe. Water is a critical prerequisite for all life-as-we-know-it, thus the possible exploration targets for extraterrestrial life are bodies that have or had copious liquid: Mars, Europa, and Enceladus. Due to the oxidizing nature of Mars' surface, as well as subsurface liquid water reservoirs present on Europa and Enceladus, the search for evidence of existing life must likely focus on subsurface locations, at depths sufficient to support liquid water or retain biologic signatures. To address these questions, an Auto-Gopher sampler has been developed that is a wireline type drill. This drill is suspended on a tether and its motors and mechanisms are built into a tube that ends with a coring bit. The tether provides the mechanical connection to a rover/lander on a surface as well as power and data communication. Upon penetrating to a target depth, the drill is retracted from the borehole, the core is deposited into a sample transfer system, and the drill is lowered back into the hole. Wireline operation sidesteps one of the major drawbacks of traditional continuous drill string systems by obviating the need for multiple drill sections, which add significantly to the mass and the complexity of the system. The Auto-gopher has been successfully tested in a laboratory environment in rock to a depth of 2 m. Field testing of the drill took place in November, 2012 at the US Gypsum quarry outside Borrego Springs, CA. The drill successfully penetrated to over 3 m depth with an average penetration rate of 1 m/hr.

  17. The dispersal of Homo sapiens across southern Asia: how early, how often, how complex?

    NASA Astrophysics Data System (ADS)

    Dennell, Robin; Petraglia, Michael D.

    2012-07-01

    The timing and the paths of colonization of southern Asia by Homo sapiens are poorly known, though many population geneticists, paleoanthropologists, and archaeologists have contended that this process began with dispersal from East Africa, and occurred between 60,000 and 40,000 years ago. However, the evidence for this scenario is very weak, particularly the lack of human skeletal evidence between the Levant and Borneo before 40 ka, and other explanations are possible. Here we argue that environmental and archaeological information is increasingly indicating the likelihood that H. sapiens exited Africa much earlier than commonly thought, and may have colonized much of southern Asia well before 60,000 years ago. Additionally, we cannot exclude the possibility that several dispersal events occurred, from both North and East Africa, nor the likelihood that early populations of H. sapiens in southern Asia interbred with indigenous populations of Neanderthals, Denisovans and Homo erectus. The population history of southern Asia during the Upper Pleistocene is likely far more complex than currently envisaged.

  18. American Images of Asia: Myth and Reality.

    ERIC Educational Resources Information Center

    Boyd, James W.; Crabtree, Loren W.

    1980-01-01

    Suggests a unit to help students confront their misinformed perceptions of Asia. Students examine seven misconceptions: unchanging Asia, the spiritual East, the indistinct Asia, the inscrutable art of Asia, the unscientific Asian, oriental despotism, and modernization as Westernization. (Author/KC)

  19. Cyptotrama (Physalacriaceae, Agaricales) from Asia.

    PubMed

    Qin, Jiao; Yang, Zhu-Liang

    2016-04-01

    Cyptotrama was divided into several sections, of which sect. Xerulina was often treated as a separate genus by some mycologists. In this study, collections of Cyptotrama from East Asia, Southeast Asia, and South Asia were studied. For comparison, materials from North America and New Zealand were analysed. Our multi-gene phylogenetic analyses indicated that Cyptotrama is monophyletic and Xerulina should be treated as a section within the genus Cyptotrama. Different scenarios of morphological character evolution in Cyptotrama are discovered. A total of seven species of Cyptotrama can be recognized from Asia, three of which, Cyptotrama angustispora, C. glabra, and C. shennongjia, are new to science. Meanwhile, three taxa previously placed in Xerulina or Marasmius were proved to be members of Cyptotrama, and the new combinations, namely Cyptotrama trogioides, C. megaspora, and C. myochroa, are accordingly proposed. A key for the diagnosis of worldwide Cyptotrama species is provided. PMID:27020153

  20. Intensity patterns in eastern Asia.

    USGS Publications Warehouse

    Evernden, J.F.

    1983-01-01

    Investigation of the intensity patterns of earthquakes of E Asia indicates a strong regional pattern of attenuation parameter k and systematic correlation of this pattern with topography, P residuals, and level of seismicity as in the USA.-Author

  1. Asia. Vancouver Conference Review.

    PubMed

    Brown, T

    1997-02-01

    The 1997 International AIDS Conference in Vancouver gave relatively little attention to the rapid spread of HIV/AIDS in most of the developing world. The popular press reported mainly prevention success stories from Thailand and Uganda, and the successes realized in reducing viral loads with combination drug therapies using protease inhibitors. Societal efforts in Thailand have dramatically reduced the rate of new infections, slowing the growth of the epidemic substantially. Few heard from the conference about how the HIV/AIDS epidemic is spreading rapidly and largely unchecked in much of the world, especially in Asia. Thailand, India, Myanmar, and Cambodia are the most heavily affected countries. Thailand and India, as well as Japan, were therefore heavily represented in the scientific program, while most other countries presented far fewer reports. With the exception of one report on a training course in Fiji, the Pacific Island nations were absent from the program. Vietnam, Malaysia, China, and Hong Kong have rapidly-evolving situations, while Japan, the Philippines, Bangladesh, Nepal, Singapore, Indonesia, Taiwan, Laos, South Korea, Mongolia, and Pakistan should be watched closely. The Asian epidemics are constantly evolving over time. PMID:9155914

  2. HIV in Southeast Asia.

    PubMed

    Abrams, S

    1998-01-01

    This article explores the HIV/AIDS epidemic in Southeast Asia. Prostitution and injecting drug use are two major factors in the appearance of HIV/AIDS in a country. But, it is the correct social network that assures its transmission to epidemic proportions. Heterosexual transmission in Cambodia, Myanmar, and Thailand is linked with prevalence among female sex workers and their clients. In Malaysia, the Ministry of Health responded immediately, but the number of new infections continued to increase. The failures suggest the need for more effective, intensive health education programs, outreach by nongovernmental organizations, and peer education at the grassroots level and in remote areas. Public health officials need to promote political change. International agencies could play an important role, if countries such as Myanmar, Cambodia, and Viet Nam were open to international exchanges. In Myanmar, political unrest has a priority over the need for aggressive health interventions. In Indonesia, the Islamic influence prevents recognition of the country's significant sex industry or the existence of a homosexual community. In Cambodia, health officials warned about the high number of sexual partners, high mobility rate, and low condom use, but HIV spread rapidly in the 1990s. Thailand initiated a 100% condom campaign to combat HIV prevalence in the 1990s, and HIV prevalence declined among sex workers and military recruits. Risk factors for rapid transmission include mobility, the number of sexual partners/sex worker, the proportion engaging in commercial sex, and the rate of regular condom use among sex workers. PMID:12294443

  3. Rheology of Lava Flows on Europa and the Emergence of Cryovolcanic Domes

    NASA Technical Reports Server (NTRS)

    Quick, Lynnae C.; Glaze, Lori S.; Baloga, Steve M.

    2015-01-01

    There is ample evidence that Europa is currently geologically active. Crater counts suggest that the surface is no more than 90 Myr old, and cryovolcanism may have played a role in resurfacing the satellite in recent geological times. Europa's surface exhibits many putative cryovolcanic features, and previous investigations have suggested that a number of domes imaged by the Galileo spacecraft may be volcanic in origin. Consequently, several Europa domes have been modeled as viscous effusions of cryolava. However, previous models for the formation of silicic domes on the terrestrial planets contain fundamental shortcomings. Many of these shortcomings have been alleviated in our new modeling approach, which warrants a re-assessment of the possibility of cryovolcanic domes on Europa.

  4. Bioluminescence: A Potentially Convergent Signature of Life in Future Exploration of Europa's Subsurface Ocean

    NASA Astrophysics Data System (ADS)

    Flores Martinez, C. L.

    2014-02-01

    This presentation deals with theoretical and evolutionary aspects pertaining to the nature and degree of biological complexity that is expectable among putative organisms on Europa. Bioluminescence is suggested as a new type of biosignature.

  5. Plumes and Tides on Europa - Implications from the 2015 HST Campaign

    NASA Astrophysics Data System (ADS)

    Rhoden, A.; Hurford, T., Jr.; Roth, L.; Retherford, K. D.

    2015-12-01

    Two plumes of water vapor emanating from Europa's southern leading hemisphere provide the best explanation for UV emissions detected by HST in Dec 2012 (Roth et al., 2014a). The detection occurred when Europa was near its orbital apocenter; there was no indication of plumes in two previous observations that occurred near pericenter. A southern location and cyclic activity peaking at apocenter are characteristic of Enceladus' plumes (Porco et al., 2006; Spencer et al., 2006; Hedman et al., 2013), which led to the suggestion that Europa also has long-lived, active plumes controlled by tides (Roth et al., 2014a). However, two subsequent observations did not result in a repeat detection, even when Europa was again near apocenter (Roth et al., 2014b). Because tidal stresses caused by eccentricity, the supposed control mechanism of Enceladus' plumes (Hurford et al., 2007; Nimmo et al., 2014), repeat exactly over each orbit, the lack of a repeat detection challenged the interpretation of tidally-modulated plumes on Europa. In Rhoden et al. (2015), we considered the role of Europa's tilted and precessing spin pole in modulating the eruption timing of the plumes. We found that, for a range of plausible precession rates (see Bills et al., 2009), tidal stresses could change substantially over subsequent orbits even for the same fracture orientation, location, and time in Europa's orbit. We then identified subsets of fractures that would have been in tension when the plumes were detected and in compression during the other four observations. An additional 15 HST observations of Europa have now been conducted over a wide range of true anomalies, with no plumes detected. Whether we would predict plumes at these times - due to tidal stress - depends on the precession rate we assume for Europa. We use the approach presented in Rhoden et al. (2015) to simultaneously fit all 20 HST observations to determine whether any fractures on Europa would be compatible with long-lived, tidally

  6. Kinetic modeling of Europa's neutral atmosphere and pick-up ions

    NASA Astrophysics Data System (ADS)

    Tenishev, V.; Rubin, M.; Borovikov, D.; Jia, X.; Combi, M. R.; Gombosi, T. I.

    2013-12-01

    Europa was the highest priority outer planet exploration target in the 2007 NASA Science Plan, the 2006 Solar System Exploration Roadmap, and the 2003 planetary sciences Decadal Survey. The in-depth exploration of the plasma environment of Jupiter's moon Europa and investigation of its interaction with moon's surface and atmosphere remains a central objective of any proposed Europa Jupiter System Mission. The neutral species in Europa's atmosphere are mostly provided by ion sputtering of the water ice surface. Energetic ions and electrons from the Jovian magnetosphere produce molecular oxygen O2, the dominant species in Europa's atmosphere. Very close to the moon's surface the probability for collisional interaction between the species is close to the limit for a surface bound exosphere. The main loss mechanisms for neutrals are electron impact ionization, photoionization, as well as escape when neutral particles leave Europa's Hill sphere at roughly 8.7 Europa radii. The neutral and plasma environment of Europa are a tightly coupled system. A detailed study of this system requires coupled models of both the plasma and neutral environment. In this study we use coupled state-of-the-art computer models developed at the University of Michigan. In particular we include the BATSRUS MHD code of the Space Weather Modeling Framework (SWMF) and the Adaptive Mesh Particle Simulator (AMPS) model based on the DSMC method that both have well proven heritage in numerous space applications. In this investigation we calculate the plasma distribution in the vicinity of Europa at different locations along its orbit. The energetic ion flux derived from these calculations is used for simulation of the neutral particle sputtering that form Europa's atmosphere. The subsequent ionization of these neutral particles is the source of the pick-up ions. Populations of the neutrals and ions are calculated by tracing trajectories of the individual particles with accounting for both Europa

  7. Respiratory infections unique to Asia.

    PubMed

    Tsang, Kenneth W; File, Thomas M

    2008-11-01

    Asia is a highly heterogeneous region with vastly different cultures, social constitutions and populations affected by a wide spectrum of respiratory diseases caused by tropical pathogens. Asian patients with community-acquired pneumonia differ from their Western counterparts in microbiological aetiology, in particular the prominence of Gram-negative organisms, Mycobacterium tuberculosis, Burkholderia pseudomallei and Staphylococcus aureus. In addition, the differences in socioeconomic and health-care infrastructures limit the usefulness of Western management guidelines for pneumonia in Asia. The importance of emerging infectious diseases such as severe acute respiratory syndrome and avian influenza infection remain as close concerns for practising respirologists in Asia. Specific infections such as melioidosis, dengue haemorrhagic fever, scrub typhus, leptospirosis, salmonellosis, penicilliosis marneffei, malaria, amoebiasis, paragonimiasis, strongyloidiasis, gnathostomiasis, trinchinellosis, schistosomiasis and echinococcosis occur commonly in Asia and manifest with a prominent respiratory component. Pulmonary eosinophilia, endemic in parts of Asia, could occur with a wide range of tropical infections. Tropical eosinophilia is believed to be a hyper-sensitivity reaction to degenerating microfilariae trapped in the lungs. This article attempts to address the key respiratory issues in these respiratory infections unique to Asia and highlight the important diagnostic and management issues faced by practising respirologists. PMID:18945321

  8. The Europa Clipper and Orbiter Mission Concepts: Innovative Approaches for Exploring Europa’s Habitability

    NASA Astrophysics Data System (ADS)

    Senske, David A.; Prockter, L.; Pappalardo, R.; Patterson, W.; Vance, S.; Science Definition, Europa; Technical Teams

    2012-10-01

    Europa is unique among the large icy satellites because it probably has a long-lived saltwater ocean beneath an ice shell that is geodynamically active. The combination of irradiation of its surface and tidal heating of its interior could make Europa a rich source of chemical energy for life. Direct contact of the ocean with a rocky mantle and potential hydrothermal activity could provide energy and nutrients to support biological activity. NASA has enlisted a study team to consider Europa mission options feasible over the next decade, compatible with NASA’s projected planetary science budget and addressing Planetary Decadal Survey priorities. Two Europa mission concepts (Orbiter and multiple flyby_call the “Clipper”) are undergoing continued study with the goal to “Explore Europa to investigate its habitability.” The Orbiter and Clipper architectures lend themselves to specific types of scientific measurements. The Orbiter concept is tailored to geophysical science that requires being in orbit at Europa. This would include confirming the existence of and characterizing the ocean along with mapping of the global morphology and topography. This architecture provides for radiation-shielded instruments with low mass, power, and data rate. The Clipper concept focuses on remote sensing science that could be accomplished through multiple close flybys of Europa. This would include exploring the ice shell for evidence of liquid water within or beneath it along with exploring the composition of the surface and atmosphere. Morphologic and topographic mapping would also be done. This architecture can provide for radiation-shielded instruments with higher mass, power, and data rate. NASA has directed the Europa team to evaluate, within a cost constrained budget, the ability of the Orbiter concept to characterize the ice shell and surface composition, and for the Clipper concept to address investigations to characterize the ocean. The status of these updated concepts

  9. A multifluid magnetohydrodynamic simulation of the interaction between Jupiter's magnetosphere and its moon Europa

    NASA Astrophysics Data System (ADS)

    Rubin, M.; Jia, X.; Altwegg, K.; Combi, M. R.; Daldorff, L. K. S.; Gombosi, T. I.; Khurana, K. K.; Kivelson, M.; Tenishev, V.; Toth, G.; van der Holst, B.; Wurz, P.

    2015-12-01

    Jupiter's moon Europa is believed to contain a subsurface water ocean whose finite electrical conductance imposes clear induction signatures on the magnetic field in its surroundings. The evidence rests heavily on measurements performed by the magnetometer on board the Galileo spacecraft during multiple flybys of the moon. Europa's interaction with the Jovian magnetosphere has become a major target of research in planetary science, partly because of the potential of a salty ocean to harbor life outside our own planet. Thus it is of considerable interest to develop numerical simulations of the Europa-Jupiter interaction that can be compared with data in order to refine our knowledge of Europa's subsurface structure. In this presentation we show aspects of Europa's interaction with the Jovian magnetosphere extracted from a multifluid magnetohydrodynamics (MHD) code BATS-R-US recently developed at the University of Michigan. The model dynamically separates magnetospheric and pick-up ions and is capable of capturing some of the physics previously accessible only to kinetic approaches. The model utilizes an adaptive grid to maintain the high spatial resolution on the surface required to resolve the portion of Europa's neutral atmosphere with a scale height of a few tens of kilometers that is in thermal equilibrium. The model also derives the electron temperature, which is crucial to obtain the local electron impact ionization rates and hence the plasma mass loading in Europa's atmosphere. We compare our results with observations made by the plasma particles and fields instruments on the Galileo spacecraft to validate our model. We will show that multifluid MHD is able to reproduce the basic features of the plasma moments and magnetic field observations obtained during the Galileo E4 and E26 flybys at Europa.

  10. Interior Characterization of Europa using Magnetometry (ICEMAG): Probing the Europan Ocean and Exosphere

    NASA Astrophysics Data System (ADS)

    Raymond, C. A.; Jia, X.; Joy, S. P.; Khurana, K. K.; Murphy, N.; Russell, C. T.; Strangeway, R. J.; Weiss, B. P.

    2015-12-01

    Magnetic induction is a powerful tool for probing the subsurface. The magnetometer on the Galileo mission to Jupiter found compelling evidence for subsurface oceans on Europa, Ganymede and Callisto; however, the single induction frequency measured did not allow characteristics of the ocean to be discerned. The Interior Characterization of Europa using MAGnetometry (ICEMAG) instrument, selected for NASA's Europa mission payload in May 2015, is designed to measure Europa's induction response at multiple frequencies with high accuracy. ICEMAG definitively assesses the ice shell thickness, and the conductivity and thickness of the subsurface ocean. This knowledge informs models of Europa's thermal evolution and allows evaluation of processes that have cycled material between the depths and the surface. Magnetic field measurements also determine the electrical currents associated with coupling of plumes to the corotating magnetospheric plasma and coupling of Europa to the Jovian ionosphere. ICEMAG utilizes UCLA fluxgate magnetic field sensors as well as JPL helium sensors in an integrated magnetic measurement system. The advent of laser-pumped helium sensors and advances in digital signal sampling enables an innovative multi-sensor magnetometer to be flown that is able to monitor spacecraft fields and maintain absolute accuracy of the measurement at a level of ~1 nT over time scales of years, without special maneuvers such as spacecraft rolls.

  11. Evidence for non-synchronous rotation of Europa. Galileo Imaging Team.

    PubMed

    Geissler, P E; Greenberg, R; Hoppa, G; Helfenstein, P; McEwen, A; Pappalardo, R; Tufts, R; Ockert-Bell, M; Sullivan, R; Greeley, R; Belton, M J; Denk, T; Clark, B; Burns, J; Veverka, J

    1998-01-22

    Non-synchronous rotation of Europa was predicted on theoretical grounds, by considering the orbitally averaged torque exerted by Jupiter on the satellite's tidal bulges. If Europa's orbit were circular, or the satellite were comprised of a frictionless fluid without tidal dissipation, this torque would average to zero. However, Europa has a small forced eccentricity e approximately 0.01 , generated by its dynamical interaction with Io and Ganymede, which should cause the equilibrium spin rate of the satellite to be slightly faster than synchronous. Recent gravity data suggest that there may be a permanent asymmetry in Europa's interior mass distribution which is large enough to offset the tidal torque; hence, if non-synchronous rotation is o