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Sample records for evolution cadre reglementaire

  1. The Evolution of the State's Cadre Policy in the Sphere of Science

    ERIC Educational Resources Information Center

    Dezhina, I.

    2007-01-01

    In the period after the collapse of the Soviet Union, cadre problems in Russian science gradually came to be included among the problems that are the most pressing and whose solutions need to be given top priority. The mass exodus of young and middle-aged qualified specialists from scientific research institutes, design bureaus, and scientific…

  2. The Impact of Cadres on School Settings.

    ERIC Educational Resources Information Center

    Thompsett, Bruce A.; Doyle, Wayne J.

    This paper assesses the impact of cross-role grouping on the social systems of participating schools. Data were gathered informally through conversations and interviews with members of cadres, cadre presentations, liaison and research evaluation personnel in specific cadres, and direct observation in some situations. The study covers three…

  3. Education for Better Governance: A Look at the Ongoing Cadre Political Education in China.

    ERIC Educational Resources Information Center

    Hua, Shucheng

    The evolution of cadre (political elite and bureaucratic functionaries) education in China from 1949 to the present was evaluated in terms of leadership development and the underlying interests of the Chinese Communist Party as it integrates more fully into the world economy. Historic achievements include: (1) increased knowledge about market…

  4. The Hyde Park Cadre As A Social System.

    ERIC Educational Resources Information Center

    Chicago Univ., IL. Ford Training and Placement Program.

    This report is a description and analysis of the Hyde Park cadre as a "social system:" a description of the Hyde Park High School, the early life of the cadre, its operations and the disbanding of the cadre in June 1970. For the most part, it deals with the cadre and its activities for the 7 1/2 month period of its existence. Data were…

  5. Space Cadre, the Warfighter’s ’Samurai Sword’

    DTIC Science & Technology

    2010-01-01

    samurai sword. It might be interesting to think of the approximately 2,500 space warriors as the “ samurai swords” of the Army bringing their own...Cadre as one would a samurai sword so that the Cadre remains relevant and keeps its sharp edge. Space Cadre, the Warfighter’s “ Samurai Sword...REPORT TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Space Cadre, the Warfighter’s ’ Samurai Sword’ 5a. CONTRACT NUMBER

  6. Technology Leadership Cadre: A Mutually Beneficial Relationship

    ERIC Educational Resources Information Center

    Lundeberg, Mary; Tikoo, So-young; Willers, Rhonda; Donley, Erin

    2004-01-01

    The purpose of this study was to explore the effects of employing preservice teachers as leaders in technology to change teacher education curriculum, and to mentor and support inservice teachers, teacher education faculty and preservice teachers. We describe the evolution of the design of this program by comparing the first and fourth year, and…

  7. Science Cadre Training in Russia and Abroad (A Comparative Analysis)

    ERIC Educational Resources Information Center

    Ismailov, E. E.

    2010-01-01

    Today the scientific potential of any country, its science cadres, the volume and scale of the research being conducted, the number of science centers, the quality and subject matter of the research, the level of the material and technical equipment of its research laboratories, and other aspects constitute a most important factor in ensuring…

  8. Science Cadre Training in Russia and Abroad (A Comparative Analysis)

    ERIC Educational Resources Information Center

    Ismailov, E. E.

    2010-01-01

    Today the scientific potential of any country, its science cadres, the volume and scale of the research being conducted, the number of science centers, the quality and subject matter of the research, the level of the material and technical equipment of its research laboratories, and other aspects constitute a most important factor in ensuring…

  9. A Hybrid Cadre Concept for International Space Station (ISS) Operations

    NASA Technical Reports Server (NTRS)

    Hagopian, Jeff; Mears, Teri

    2000-01-01

    The International Space Station (ISS) is a continuously operating on-orbit facility, with a ten to fifteen year lifetime. The staffing and rotation concepts defined and implemented for the ISS program must take into account the unique aspects associated with long duration mission operations. Innovative approaches to mission design and operations support must be developed and explored which address these unique aspects. Previous National Aeronautics and Space Administration (NASA) man-based space programs, with the exception of Skylab, dealt primarily with short duration missions with some amount of down time between missions; e.g., Shuttle, Spacelab, and Spacehab programs. The ISS Program on the other hand requires continuous support, with no down time between missions. ISS operations start with the first element launch and continue through the end of the program. It is this key difference between short and long duration missions that needs to be addressed by the participants in the ISS Program in effectively and efficiently staffing the positions responsible for mission design and operations. The primary drivers considered in the development of staffing and rotation concepts for the ISS Program are budget and responsiveness to change. However, the long duration aspects of the program necessitate that personal and social aspects also be considered when defining staffing concepts. To satisfy these needs, a Hybrid Cadre concept has been developed and implemented in the area of mission design and operations. The basic premise of the Hybrid Cadre concept is the definition of Increment-Independent and Increment-Dependent cadre personnel. This paper provides: definitions of the positions required to implement the concept, the rotation scheme that is applied to the individual positions, and a summary of the benefits and challenges associated with implementing the Hybrid Cadre concept.

  10. Adjacent segment disease and C-ADR: promises fulfilled?

    PubMed Central

    Riew, K Daniel; Schenk-Kisser, Jeannette M.; Skelly, Andrea C.

    2012-01-01

    Study design: Systematic review. Clinical question: Do the rates and timing of adjacent segment disease (ASD) differ between cervical total disc arthroplasty (C-ADR) and anterior cervical discectomy and fusion (ACDF) in patients treated for cervical degenerative disc disease? Methods: A systematic search of MEDLINE/PubMed and bibliographies of key articles was done to identify studies with long-term follow-up for symptomatic and/or radiographic ASD comparing C-ADR with fusion for degenerative disc disease of the cervical spine. The focus was on studies with longer follow-up (48–60 months) of primary US Food and Drug Administration trials of Prestige ST, Prodisc-C, and Bryan devices as available. Trials of other discs with a minimum of 24 months follow-up were considered for inclusion. Studies evaluating lordosis/angle changes at adjacent segments and case series were excluded. Results: From 14 citations identified, four reports from three randomized controlled trials and four nonrandomized studies are summarized. Risk differences between C-ADR and ACF for symptomatic ASD were 1.5%–2.3% and were not significant across RCT reports. Time to development of ASD did not significantly differ between treatments. Rates of radiographic ASD were variable. No meaningful comparison of ASD rates based on disc design was possible. No statistical differences in adjacent segment range of motion were noted between treatment groups. Conclusion: Our analysis reveals that, to date, there is no evidence that arthroplasty decreases ASD compared with ACDF; the promise of arthroplasty decreasing ASD has not been fulfilled. PMID:23236312

  11. Coming Soon: CADRE (Career Advancement and Development Resources and Education) website for all APS members

    USDA-ARS?s Scientific Manuscript database

    The Council of the American Phytopathological Society (APS) approved an initiative in February 2013 to create a web resource called CADRE (Career Advancement and Development Resources and Education). CADRE is to provide APS members an archive of articles, videos, and webinars about a variety of prof...

  12. Wisconsin Vocational Equity Leadership Cadre Support Project. Final Report. FY96.

    ERIC Educational Resources Information Center

    Riley, Linda L.

    A project provided technical assistance and support to the Wisconsin Vocational Equity Leadership Cadre to enable them to assist local districts in meeting the equity assurances in the Carl D. Perkins Vocational and Applied Technology Education Act of 1990. Approximately 80 members of the cadre, educators responsible for providing regional…

  13. The Impact of Family Background on College Students' Chances of Serving as Student Union Cadres

    ERIC Educational Resources Information Center

    Xinzhuo, Zhu; Junhua, Shi; Zhihui, Dong

    2015-01-01

    A survey and comparative analysis of the family backgrounds of the entire undergraduate student body of X University and the group of student union cadres shows: the proportion of college students who serve as student union cadres who come from cities and have families with high social status, high family income, and parents with high educational…

  14. Communist Cadres and Market Opportunities: Entry into Self-employment in China, 1978-1996

    ERIC Educational Resources Information Center

    Wu, Xiaogang

    2006-01-01

    This paper examines the patterns of entry into self-employment in urban and rural China and across different reform stages, focusing on how communist cadres have responded to new market opportunities. Analysis of data from a national representative survey shows that both education and cadre status deter people from entry into self-employment in…

  15. Evolution.

    ERIC Educational Resources Information Center

    Mayr, Ernst

    1978-01-01

    Traces the history of evolution theory from Lamarck and Darwin to the present. Discusses natural selection in detail. Suggests that, besides biological evolution, there is also a cultural evolution which is more rapid than the former. (MA)

  16. Evolution.

    ERIC Educational Resources Information Center

    Mayr, Ernst

    1978-01-01

    Traces the history of evolution theory from Lamarck and Darwin to the present. Discusses natural selection in detail. Suggests that, besides biological evolution, there is also a cultural evolution which is more rapid than the former. (MA)

  17. In situ Micrometeorological Measurements during RxCADRE

    NASA Astrophysics Data System (ADS)

    Clements, C. B.; Hiers, J. K.; Strenfel, S. J.

    2009-12-01

    The Prescribed Fire Combustion and Atmospheric Dynamics Research Experiment (RxCADRE) was a collaborative research project designed to fully instrument prescribed fires in the Southeastern United States. Data were collected on pre-burn fuel loads, post burn consumption, ambient weather, in situ atmospheric dynamics, plume dynamics, radiant heat release (both from in-situ and remote sensors), in-situ fire behavior, and select fire effects. The sampling was conducted at Eglin Air Force Base, Florida, and the Joseph W. Jones Ecological Research Center in Newton, Georgia, from February 29 to March 6, 2008. Data were collected on 5 prescribed burns, totaling 4458 acres. The largest aerial ignition totaled 2,290 acres and the smallest ground ignition totaled 104 acres. Quantifying fire-atmospheric interactions is critical for understanding wildland fire dynamics and enhancing modeling of smoke plumes. During Rx-CADRE, atmospheric soundings using radiosondes were made at each burn prior to ignition. In situ micrometeorological measurements were made within each burn unit using five portable, 10-m towers equipped with sonic and prop anemometers, fine-wire thermocouples, and a carbon dioxide probes. The towers were arranged within the burn units to capture the wind and temperature fields as the fire front and plume passed the towers. Due to the interaction of fire lines following ignition, several of the fire fronts that passed the towers were backing fires and thus less intense. Preliminary results indicate that the average vertical velocities associated with the fire front passage were on the order of 3-5 m s-1 and average plume temperatures were on the order of 30-50 °C above ambient. During two of the experimental burns, radiosondes were released into the fire plumes to determine the vertical structure of the plume temperature, humidity, and winds. A radiosonde released into the plume during the burn conducted on 3 March 2008 indicated a definite plume boundary in the

  18. A global picture of pharmacy technician and other pharmacy support workforce cadres.

    PubMed

    Koehler, Tamara; Brown, Andrew

    Understanding how pharmacy technicians and other pharmacy support workforce cadres assist pharmacists in the healthcare system will facilitate developing health systems with the ability to achieve universal health coverage as it is defined in different country contexts. The aim of this paper is to provide an overview of the present global variety in the technician and other pharmacy support workforce cadres considering; their scope, roles, supervision, education and legal framework. A structured online survey instrument was administered globally using the Survey Monkey platform, designed to address the following topic areas: roles, responsibilities, supervision, education and legislation. The survey was circulated to International Pharmaceutical Federation (FIP) member organisations and a variety of global list serves where pharmaceutical services are discussed. 193 entries from 67 countries and territories were included in the final analysis revealing a vast global variety with respect to the pharmacy support workforce. From no pharmacy technicians or other pharmacy support workforce cadres in Japan, through a variety of cadre interactions with pharmacists, to the autonomous practice of pharmacy support workforce cadres in Malawi. From strictly supervised practice with a focus on supply, through autonomous practice for a variety of responsibilities, to independent practice. From complete supervision for all tasks, through geographical varied supervision, to independent practice. From on the job training, through certificate level vocational courses, to 3-4 year diploma programs. From well-regulated and registered, through part regulation with weak implementation, to completely non-regulated contexts. This paper documents wide differences in supervision requirements, education systems and supportive legislation for pharmacy support workforce cadres globally. A more detailed understanding of specific country practice settings is required if the use of pharmacy

  19. Expression of cadR Enhances its Specific Activity for Cd Detoxification and Accumulation in Arabidopsis.

    PubMed

    Li, Jingrui; Wei, Xuezhi; Yu, Pengli; Deng, Xin; Xu, Wenxiu; Ma, Mi; Zhang, Haiyan

    2016-08-01

    Cadmium (Cd) is a transition metal that is highly toxic in biological systems. Anthropogenic emissions of Cd have increased biogeochemical cycling and the amount of Cd in the biosphere. Here we studied the utility of a bacterial Cd-binding protein, CadR, for the remediation of Cd contamination. CadR was successfully targeted to chloroplasts using a constitutive Cauliflower mosaic virus (CaMV) 35S promoter or a shoot-specific Chl a/b-binding protein 2 gene (CAB2) promoter and an RbcS (small subunit of the Rubisco complex) transit peptide. Under short-term (2 d) exposure to Cd, the cadR transgenic plants showed up to a 2.9-fold Cd accumulation in roots compared with untransformed plants. Under medium term (7 d) exposure to Cd, the concentrations of Cd in leaves began to increase but there were no differences between the wild type and the cadR transgenic plants. Under long-term (16 d) exposure to Cd, the cadR transgenic plants accumulated greater amounts of Cd in leaves than the untransformed plants. Total Cd accumulation (µg per plant) in shoots and roots of the plants expressing cadR were significantly higher (up to 3.5-fold in shoots and 5.2-fold in roots) than those of the untransformed plants. We also found that targeting CadR to chloroplasts facilitated chloroplastic metal homeostasis and Chl b accumulation. Our results demonstrate that manipulating chelating capacity in chloroplasts or in the cytoplasm may be effective in modifying both the accumulation of and resistance to Cd.

  20. Reversing the Trend: Creating a Growing and Sustainable Cadre of Safeguards Experts in the United States

    SciTech Connect

    Lockwood, Dunbar; Mathews, Caroline E.; Seward, Amy M.

    2008-07-17

    In October 2007, the National Nuclear Security Administration’s (NNSA) Office of Non-Proliferation and International Security (NA-24) completed a wide-ranging study on international safeguards issues that found, inter alia, that the human capital base in the United States must be revitalized and expanded to ensure a seamless succession from the current generation of safeguards experts. Many current safeguards experts will soon retire and a new generation of talent with capabilities that cover the full spectrum of safeguards-relevant disciplines is needed. The success of this effort will have direct bearing on the International Atomic Energy Agency (IAEA). An effective international safeguards system that responds to current and future nonproliferation challenges requires a cadre of skilled safeguards specialists. However, a number of factors have converged in recent years that have challenged the IAEA’s ability to effectively carry out its safeguards mission, e.g. flat funding, expanding responsibilities, and several ad hoc high profile investigations. In the near future, the Agency will require increased numbers of qualified staff to address the expansion and evolution of its mission and anticipated worldwide growth in nuclear energy production. Without a large-scale effort to address this requirement in the near future, the international community will have far less confidence that nuclear material in civil programs is not being diverted for nuclear weapons and the risks of nuclear proliferation will increase around the world. This paper will describe in detail NNSA’s efforts, in coordination with other federal agencies, to address the safeguards human resources challenge, focusing on the recommendations of the Next Generation Safeguards Initiative (NGSI).

  1. Mid-level cadre providing eye care in the context of Vision 2020.

    PubMed

    du Toit, Renee; Brian, Garry

    2009-03-13

    The contribution of the mid-level cadre of eye care providers is an essential component of the Vision 2020: The Right To Sight initiative, to eliminate avoidable blindness by 2020. However, for the past 20 years the functions of this cadre have not been definitively outlined, or universally accepted. Consequently, the competencies they require to provide high quality comprehensive eye care have not been established. This has had implications for both training programmes and the subsequent deployment of the graduates of these programmes. This paper examines, mainly through a review of World Health Organization (WHO) documentation, the progress that has been made in defining the role and outlining appropriately enabling training of this cadre of mid-level personnel. As a result of this analysis, recommendations are made concerning the development of this cadre to provide eye care in the context of Vision 2020: *Develop consistent and widely applicable nomenclature *Outline workplace functions and job descriptions, so that personnel can be categorised by their competencies and functions. *Develop curricula based on the competency requirements of job descriptions and that will prepare personnel for those jobs. *Establish and/or develop training centres, including those capable of training trainers. *Establish government recognition, resources, support, and evaluation and feedback systems to ensure that this mid-level cadre can implement their training, and have the opportunity of providing high quality eye care.

  2. Evolution

    NASA Astrophysics Data System (ADS)

    Peter, Ulmschneider

    When we are looking for intelligent life outside the Earth, there is a fundamental question: Assuming that life has formed on an extraterrestrial planet, will it also develop toward intelligence? As this is hotly debated, we will now describe the development of life on Earth in more detail in order to show that there are good reasons why evolution should culminate in intelligent beings.

  3. Change and Challenge: A Longitudinal Study of an Accelerated School Parent Involvement Cadre.

    ERIC Educational Resources Information Center

    Ferrara, Margaret M.; Knight, Stephanie L.

    The Accelerated Schools program is a popular school restructuring model that targets at-risk students. To serve at-risk students better under the Accelerated Schools program, schools must establish a governance program in which cadres of school practitioners and community members become involved in the decision making. Decisions of these cadres…

  4. Wisconsin Vocational Equity Leadership Cadre Support Project. FY 95. Final Report.

    ERIC Educational Resources Information Center

    Riley, Linda L.

    A project was developed to provide technical assistance and staff development to the Wisconsin Vocational Equity Leadership Cadre to enable them to assist local districts in meeting the equity assurances in the Carl D. Perkins Vocational and Applied Technology Education Act of 1990 as well as Wisconsin's equity goals as prescribed in state law.…

  5. Storm of Fire (1978): Reflections on Cadre Films and the Historian as Filmmaker.

    ERIC Educational Resources Information Center

    Rollins, Peter C.

    1979-01-01

    Outlines the working assumptions of the Cadre filmmaking group, including their demand for active viewing, and close attention to imagery, editing, and the relationship between sound and image. Shows how these ideas were utilized in their latest film, "Storm of Fire." (CK)

  6. State Scan--Residential Placements: Blind/VI and Deaf/HI. Information Research Cadre

    ERIC Educational Resources Information Center

    Blythe, Teresa

    2013-01-01

    In this Information Research Cadre, Teresa Blythe responds to the following research question: For those states that have residential schools for the Blind/VI and Deaf/HI students, have they developed policies and procedures for residential placement of these students? To develop this response Blythe conducted web research utilizing numerous…

  7. Development and validation of fuel height models for terrestrial lidar - RxCADRE 2012

    Treesearch

    Eric M. Rowell; Carl A. Seielstad; Roger D. Ottmar

    2016-01-01

    Terrestrial laser scanning (TLS) was used to collect spatially continuous measurements of fuelbed characteristics across the plots and burn blocks of the 2012 RxCADRE experiments in Florida. Fuelbeds were scanned obliquely from plot/block edges at a height of 20 m above ground. Pre-fire blocks were scanned from six perspectives and four perspectives for post-...

  8. Non-doctor anaesthesia in Nepal: developing an essential cadre.

    PubMed

    Zimmerman, Mark; Lee, Maurice; Retnaraj, Samson

    2008-07-01

    Nepal is a mountainous country of 27 million people where the widespread lack of access to operative services is a major cause of morbidity and mortality. One critical reason for this is the lack of trained, appropriately distributed anaesthesia providers. We discuss the evolution of the 'anaesthesia assistant' in Nepal, review the international literature concerning the development of non-doctor anaesthetists, and invite links with others working in this field.

  9. An exploratory investigation of relationships among mental skills and resilience in Warrior Transition Unit cadre members.

    PubMed

    Pickering, Michael A; Hammermeister, Jon; Ohlson, Carl; Holliday, Bernie; Ulmer, Graham

    2010-04-01

    Warrior transition unit (WTU) cadre members are exposed to a variety of stressors that put them at risk for adverse conditions and events. Resilience may be a construct capable of moderating some of these potential negative outcomes. In turn, mental toughness is a concept associated with resilience that may provide a unique framework from which to train resilient behavior. This article explored associations between resilience and several mental skills that are assumed to be related to mental toughness, in a sample (n = 27) of WTU cadre members in the U.S. Army. Instruments included the Ottawa Mental Skills Inventory (OMSAT-3) and the Resilience Scale (RS). Both cognitive mental skills and emotion management skills were positively associated with resilience. Results also indicated a model specifying emotion management as a mediator of the relationship between cognitive skills and resilience was consistent with the study data.

  10. More than skin deep. Ten year follow-up of delayed cutaneous adverse drug reactions (CADR).

    PubMed

    Graudins, Linda Velta; Ly, Jenny; Trubiano, Jason; Aung, Ar Kar

    2016-10-01

    To determine the gaps in practice regarding appropriate ADR documentation and risk communication for patients diagnosed with severe cutaneous adverse drug reactions (CADR). This was a retrospective observational cohort study conducted using hospital coding and databases to identify inpatients diagnosed with CADR from January 2004 to August 2014. Hospital discharge summaries, ADR reports and pharmacy dispensing records were reviewed for ADR documentation. Patients still living in Australia and who did not opt out of being contacted were invited to be surveyed by telephone to determine their understanding of recommendations, re-exposure rates and long-term effects. Of 85 patients identified, median age was 59 (IQR 44-72) years and 47.1% were male. The most common diagnosis was TENS (49.4%). Ten patients (11.8%) died as inpatients. Of the 81 patients with a drug-related causality, 47 (58%) had appropriate documentation in all three required medical record platforms. Of the 56 eligible patients, 38 (67.9%) were surveyed; 13% had no information provided upon discharge and 26.3% patients had a mismatch in knowledge of implicated medications. No surveyed patient had a relapse of CADR, but 23.7% had a subsequent unrelated allergic reaction. Thirteen patients (34.2%) reported long-term effects. We found gaps in the accuracy of ADR documentation and communication of risk at discharge, which indicated risks to patient safety. Electronic systems are being developed to improve documentation. Written information about CADR is being provided at discharge to improve patient understanding and knowledge. © 2016 The British Pharmacological Society.

  11. Purposeful Development of the Intelligence, Surveillance, and Reconnaissance for Space Cadre

    DTIC Science & Technology

    2016-07-13

    November–December 2015 | 31 Views Purposeful Development of the Intelligence, Surveillance, and Reconnaissance for Space Cadre SMSgt Mitchell R...of the US government. This article may be reproduced in whole or in part without permission. If it is reproduced, the Air and Space Power Journal...requests a courtesy line. Protecting space assets is critical to AF ISR operations and the nation’s full spectrum joint operations. Purposefully

  12. Elaboration d'un environnement d'experimentation en simulation incluant un cadre theorique pour l'apprentissage de l'energie des fluides

    NASA Astrophysics Data System (ADS)

    Cervera, Daniel

    Dans cette these, nous presentons la demarche et les diverses etapes qui nous ont conduits a l'elaboration d'un environnement d'experimentation en simulation assistee par ordinateur, incluant un cadre theorique, susceptible d'ameliorer l'apprentissage des concepts relies aux phenomenes qui se produisent dans les systemes technologiques fermes impliquant des fluides (gaz et liquides), tels les systemes hydrauliques et pneumatiques industriels, les systemes de refrigeration, de climatisation et de chauffage. Ces phenomenes ne sont pas directement observables et leur evolution obeit aux interactions complexes qui se produisent a l'interieur des systemes, ce qui leur confere un caractere particulierement abstrait et difficile a comprendre. Notre demarche a consiste a concevoir cet environnement d'apprentissage a partir d'une situation problematique qui se caracterise notamment par la presence de fausses representations conceptuelles chez les etudiants et par la complexite des phenomenes impliques dans les systemes en question. Nous avons conceptualise un environnement d'apprentissage interactif d'inspiration essentiellement constructiviste, base sur l'experimentation et la modelisation didactique et qui permet a l'etudiant d'observer simultanement et en temps reel le comportement des systemes et l'evolution des variables au moyen de graphiques. Aussi, nous avons elabore un cadre theorique pour l'apprentissage de l'energie des fluides, de nature semblable a celui qui existe pour les circuits electriques. Ce cadre theorique explicite les regles qui sous-tendent la maniere dont les fluides se distribuent dans les circuits et permet d'articuler une analyse du comportement des systemes. Nous avons realise deux prototypes de l'environnement d'apprentissage. Le premier a permis de verifier la faisabilite technologique et l'interet didactique des principales orientations du projet. Le deuxieme prototype a ete concu et realise dans le cadre d'une entente de partenariat de type

  13. School/University Partnerships and the UNI Teaching Associates Cadre Model: Professional Benefits to PreK-12 Educators.

    ERIC Educational Resources Information Center

    Selke, Mary J.; Kueter, Roger A.

    The implementation of the University of Northern Iowa's (UNI) Teaching Associates Cadre Model (TAC) Professional Development School (PDS) program is discussed within the context of Kagan's six stages of collaborative relationships: formation, conceptualization, development, implementation, evaluation, and termination or reformation. The TAC was…

  14. Young People's Attitude toward Education as a Factor in Improving the Effectiveness of Training Highly Qualified Cadres

    ERIC Educational Resources Information Center

    Zubok, Iu. A.; Chuprov, V. I.

    2013-01-01

    Research shows that in contemporary Russian society there is an increasingly acute contradiction between society's need for the training of professional cadres who are able to meet modern standards, and young people's attitudes toward education. Resolving this contradiction will require both changes in the system of education in Russia and changes…

  15. Return to work rates and activity profiles: are there differences between those receiving C-ADR and ACDF?

    PubMed Central

    Traynelis, Vincent C.; Leigh, Barbara C.; Skelly, Andrea C.

    2012-01-01

    Study design: Comparative effectiveness review. Study rationale: The ability of a patient to return to work and the speed with which this occurs are important outcome metrics for the assessment of patients undergoing spinal surgery. Clinical questions: In patients with degenerative disease of the cervical spine, does cervical artificial disc replacement (C-ADR) lead to better work-related outcomes than fusion? Does return to work after surgery differ based on gender, age, smoking, litigation status, workers’ compensation status, or other sociodemographic factors? Methods: A systematic search and review of the English-language literature was undertaken to identify studies published through October 2, 2011. PubMed, Cochrane, National Guideline Clearinghouse Databases, and bibliographies of key articles were searched. Two individuals independently reviewed articles based on inclusion and exclusion criteria, which were set a priori. Each article was evaluated using a predefined quality-rating scheme. Results: For follow-up periods of more than 6 months, there was no significant difference in work status between disc replacement and fusion patients; however, C-ADR patients began working sooner after surgery. Statistical significance for earlier return was not reached in all studies. Conclusions: Most patients undergoing cervical decompression and fusion or C-ADR return to work. The rates are equivalent at 6 months but patients treated with C-ADR resumed work sooner. PMID:23236313

  16. Measuring radiant emissions from entire prescribed fires with ground, airborne and satellite sensors - RxCADRE 2012

    Treesearch

    Matthew B. Dickinson; Andrew T. Hudak; Thomas Zajkowski; E. Louise Loudermilk; Wilfrid Schroeder; Luke Ellison; Robert L. Kremens; William Holley; Otto Martinez; Alexander Paxton; Benjamin C. Bright; Joseph O' Brien; Ben Hornsby; Charles Ichoku; Jason Faulring; Aaron Gerace; David Peterson; Joseph Mauceri

    2016-01-01

    Characterising radiation from wildland fires is an important focus of fire science because radiation relates directly to the combustion process and can be measured across a wide range of spatial extents and resolutions. As part of a more comprehensive set of measurements collected during the 2012 Prescribed Fire Combustion and Atmospheric Dynamics Research (RxCADRE)...

  17. Rx-CADRE (Prescribed Fire Combustion-Atmospheric Dynamics Research Experiments) collaborative research in the core fire sciences

    Treesearch

    D. Jimenez; B. Butler; K. Hiers; R. Ottmar; M. Dickinson; R. Kremens; J. O' Brien; A. Hudak; C. Clements

    2009-01-01

    The Rx-CADRE project was the combination of local and national fire expertise in the field of core fire research. The project brought together approximately 30 fire scientists from six geographic regions and seven diff erent agencies. The project objectives were to demonstrate the capacity for collaborative research by bringing together individuals and teams with a...

  18. Participatory ergonomics: determining injury control "buy-in" of US Army cadre.

    PubMed

    Berg Rice, Valerie J; Pekarek, Deanna; Connolly, Vicki; King, Ileana; Mickelson, Shelia

    2002-01-01

    Overuse injuries account for the majority of lost duty time profiles for soldiers attending Advanced Individual Training (AIT) to become a Combat Medic at Ft. Sam Houston (63% for men and 74% for women). An intervention program was initiated with two AIT Battalions (BN) in an effort to reduce overuse injuries. The purpose of this paper is to describe methods of tracking the participation of supervisors during the intervention program. Methods used to monitor participation included recording the number of coordinating meetings, keeping minutes of advisory committee meetings, and conducting perception surveys. Over an 18-month period, the number of coordinating meetings decreased. Surveys identified the opinions, values, and self-identified roles of supervisors (drill sergeants and cadre) in regard to injury prevention with their assigned student-soldiers before and after an intervention program. At the initiation of the injury control program, 103 individuals completed a 27 question, anonymous survey to assist planners with developing a strategy that would encourage participation of cadre and drill sergeants in preventing injuries. One year later, 191 individuals from the same battalion completed the same survey. Results revealed a slight, statistically insignificant, decrease in supervisors' perception of the presence of overuse injuries in their BN (31.4% vs. 27.4%, p>0.05), and the level of acceptable injuries moved from the 16-30% range to the 1-10% range (chi2=4.65, p<0.05). Post-intervention, more supervisors believed their physical training programs could impact overuse injuries (pre 20.4% vs. post 31.6%, Chi2=6.7, p<0.01). The results reveal several methods to track the involvement of participants, to develop intervention strategies, and to monitor cultural shifts necessary to the injury control process.

  19. Evaluation of a Well-Established Task-Shifting Initiative: The Lay Counselor Cadre in Botswana

    PubMed Central

    Ledikwe, Jenny H.; Kejelepula, Mable; Maupo, Kabelo; Sebetso, Siwulani; Thekiso, Mothwana; Smith, Monica; Mbayi, Bagele; Houghton, Nankie; Thankane, Kabo; O’Malley, Gabrielle; Semo, Bazghina-werq

    2013-01-01

    Background Evidence supports the implementation of task shifting to address health worker shortages that are common in resource-limited settings. However, there is need to learn from established programs to identify ways to achieve the strongest, most sustainable impact. This study examined the Botswana lay counselor cadre, a task shifting initiative, to explore effectiveness and contribution to the health workforce. Methods This evaluation used multiple methods, including a desk review, a national lay counselor survey (n = 385; response = 94%), in-depth interviews (n = 79), lay counselors focus group discussions (n = 7), lay counselors observations (n = 25), and client exit interviews (n = 47). Results Interview and focus group data indicate that lay counselors contribute to essentially all HIV-related programs in Botswana and they conduct the majority of HIV tests and related counseling at public health facilities throughout the country. Interviews showed that the lay counselor cadre is making the workload of more skilled health workers more manageable and increasing HIV acceptance in communities. The average score on a work-related knowledge test was 74.5%. However for 3 questions, less than half answered correctly. During observations, lay counselors demonstrated average competence for most skills assessed and clients (97.9%) were satisfied with services received. From the survey, lay counselors generally reported being comfortable with their duties; however, some reported clinical duties that extended beyond their training and mandate. Multiple factors affecting the performance of the lay counselors were identified, including insufficient resources, such as private counseling space and HIV test kits; and technical, administrative, and supervisory support. Conclusion Lay counselors are fulfilling an important role in Botswana's healthcare system, serving as the entry point into HIV care, support, and treatment services. Recommendation

  20. Recent picture of infective endocarditis in Japan--lessons from Cardiac Disease Registration (CADRE-IE).

    PubMed

    Nakatani, Satoshi; Mitsutake, Kotaro; Ohara, Takahiro; Kokubo, Yoshihiro; Yamamoto, Haruko; Hanai, Sotaro

    2013-01-01

     It is important to manage a potentially fatal disease such as infective endocarditis (IE) based on evidence and guidelines for treatment published by academic societies. To clarify the current status of IE in Japan, we conducted a nationwide survey of IE (CArdiac Disease REgistration-Infective Endocarditis [CADRE-IE]).  We collected data on every aspect of IE using web-based survey. Only a Japanese Circulation Society-certified cardiologists who had managed a case of IE could register the patient when the outcome was known. There were 513 cases (320 men, 193 women) from 114 institutions. The median age was 61 years and more than 80% of the patients had underlying cardiac diseases. The majority was valvular heart disease, in which mitral regurgitation was a leading cause. Most of the patients had some predisposing factors, among which, decayed teeth or periodontitis was a leading factor. Streptococci were found in approximately 52% and staphylococci were found in 32% in positive-culture cases. Methicillin-resistant Staphylococcus aureus was found in 7.5%. Congestive heart failure was found in 43% and intracranial complications were found in 31%. Most of the patients were discharged (65%) but in-hospital death occurred in 11%.  IE is still a lethal disease affecting older patients. The information obtained from the survey should be very helpful for physicians. 

  1. Best Practices in Organizing a Cadre of Undergraduate Science Outreach Students

    NASA Astrophysics Data System (ADS)

    Pompea, S. M.; Walker, C. E.; Sparks, R.

    2011-12-01

    Engaging future scientists, while they are undergraduates, in education and public outreach is an effective strategy for ensuring future participation in high-quality education and public outreach. Since 2003, the National Optical Astronomy Observatory has organized undergraduate science students for education and public outreach work. This outreach cadre has proven remarkably successful at running star parties, working with schools and afterschool programs such as at the Boys and Girls Clubs, conducting special projects related to Spanish language astronomy education materials, and in building kits for use in outreach. They have also done programs with portable planetariums and have even fixed a planetarium projector. Students have also played integral roles in several NSF-funded education projects such as Hands-On Optics. We explain our model for recruiting, training, and organizing our team of 5-7 students. These students are paid for their work but also are mentored in science, their coursework, and in other skills critical for professional success. Notably, a large number of these students have gone on to pursue graduate work. We also describe our use of undergraduate students who participated in our outreach work as part of the Collaboration to Advance Teaching Technology and Science NSF GK-12 project.

  2. Implementation of the Community Health Assistant (CHA) Cadre in Zambia: A Process Evaluation to Guide Future Scale-Up Decisions.

    PubMed

    Shelley, Katharine D; Belete, Yekoyesew W; Phiri, Sydney Chauwa; Musonda, Mutinta; Kawesha, Elizabeth Chizema; Muleya, Evelyn Mutinta; Chibawe, Caroline Phiri; van den Broek, Jan Willem; Vosburg, Kathryn Bradford

    2016-04-01

    Universal health coverage requires an adequate health workforce, including community health workers (CHWs) to reach rural communities. To improve healthcare access in rural areas, in 2010 the Government of Zambia implemented a national CHW strategy that introduced a new cadre of healthcare workers called community health assistants (CHAs). After 1 year of training the pilot class of 307 CHAs deployed in September 2012. This paper presents findings from a process evaluation of the barriers and facilitators of implementation of the CHA pilot, along with how evidence was used to guide ongoing implementation and scale-up decisions. Qualitative inquiry was used to assess implementation during the first 6 months of the program rollout, with 43 in-depth individual and 32 small group interviews across five respondent types: CHAs, supervisors, volunteer CHWs, community members, and district leadership. Potential 'implementation moderators' were explored using deductive coding and thematic analysis of participant perspectives on community acceptance of CHAs, supervision support mechanisms, and coordination with volunteer CHWs, and health system integration of a new cadre. Community acceptance of CHAs was generally high, but coordination between CHAs and existing volunteer CHWs presented some challenges. The supervision support system was found to be inconsistent, limiting assurance of consistent quality care delivered by CHAs. Underlying health system weaknesses regarding drug supply and salary payments furthermore hindered incorporation of a new cadre within the national health system. Recommendations for implementation and future scale based on the process evaluation findings are discussed.

  3. Task-shifting impact of introducing a pilot community health worker cadre into Zambia’s public sector health workforce

    PubMed Central

    Keller, Brett; McCarthy, Elizabeth; Bradford Vosburg, Kathryn; Musonda, Mutinta; Mwila, Jere; van den Broek, Jan Willem

    2017-01-01

    Background The Zambia Ministry of Health (MOH) recruited and trained a new cadre of Community Health Assistants (CHAs) as part of its National Community Health Strategy. The inaugural class of 307 CHAs completed one year of training in July 2012 and deployed to their communities. Methods The impact of the CHA program on the volume and type of health services provided at health posts and their respective referral health centers was measured with a non-randomized difference-in-differences design. Monthly health service provision data was collected for 12 months before and after CHA deployment at 8 health posts along with 8 referral health centers. The analysis controlled for seasonality, changes in non-CHA staffing, and periodic regional child health campaigns, and used facility-level fixed effects. Results Deploying two CHAs to a health post did not lead to a statistically-discernible increase in services at the intervention facilities. Health services provided at referral health centers increased by 697.9 services per month (95% CI: 131.4 to 1,264.3, p = .016), and combined services (at health posts and referral health centers) increased by 848.6 services per month (95% CI: 178.2 to 1,519.1, p = .013). Conclusion In this pilot, the addition of CHAs in rural areas increased health service provision at referral health facilities and at facilities overall, shifting the burden of basic health services away from more highly trained health workers. Shifting tasks to lesser-trained, less-expensive cadres like the CHAs, policymakers can rapidly improve access to care with constrained budgets. Evaluations measuring the direct impact of lower level cadres without accounting for task-shifting may underestimate their contribution to the health workforce. PMID:28767719

  4. Skilled birth attendants in Tanzania: a descriptive study of cadres and emergency obstetric care signal functions performed.

    PubMed

    Ueno, Etsuko; Adegoke, Adetoro A; Masenga, Gileard; Fimbo, Janeth; Msuya, Sia E

    2015-01-01

    Although most developing countries monitor the proportion of births attended by skilled birth attendants (SBA), they lack information on the availability and performance of emergency obstetric care (EmOC) signal functions by different cadres of health care providers (HCPs). The World Health Organisation signal functions are set of key interventions that targets direct obstetric causes of maternal deaths. Seven signal functions are required for health facilities providing basic EmOC and nine for facilities providing comprehensive EmOC. Our objectives were to describe cadres of HCPs who are considered SBAs in Tanzania, the EmOC signal functions they perform and challenges associated with performance of EmOC signal functions. We conducted a cross-sectional study of HCPs offering maternity care services at eight health facilities in Moshi Urban District in northern Tanzania. A questionnaire and health facility assessment forms were used to collect information from participants and health facilities. A total of 199 HCPs working at eight health facilities in Moshi Urban District met the inclusion criteria. Out of 199, 158 participated, giving a response rate of 79.4 %. Ten cadres of HCPs were identified as conducting deliveries regardless of the level of health facilities. Most of the participants (81 %) considered themselves SBAs, although some were not considered SBAs by the Ministry of Health and Social Welfare (MOHSW). Only two out of the eight facilities provided all of the required EmOC signal functions. While Assistant Medical Officers are expected to perform all the signal functions, only 38 % and 13 % had performed vacuum extraction or caesarean sections respectively. Very few registered and enrolled nurse-midwives had performed removal of retained products (22 %) or assisted vaginal delivery (24 and 11 %). Inadequate equipment and supplies, and lack of knowledge and skills in performing EmOC were two main challenges identified by health care providers in all

  5. Fiche pratique: Le discours rapporte; Le chagrin et al pitie; Les cadres; Fort de cafe (Practical Ideas: Retold Stories; Shame and Pity; Settings; Full of Coffee).

    ERIC Educational Resources Information Center

    Store-Rao, Neelanbari; And Others

    1994-01-01

    Four ideas for French language instruction are described, including an exercise in summarizing or retelling something told to one; an exercise in descriptive and expressive language; an exploration of the different uses of the word "cadre"; and activities related to coffee in different cultures. (MSE)

  6. A Modest Proposal: For Preventing Space Operations from Being a Burden to the Navy, and for Making the Space Cadre Beneficial to the Community

    DTIC Science & Technology

    2007-09-01

    ripen the fruits of formal education. Further, the space systems that the Navy depends upon for communication, navigation, surveillance, and...career paths.131 This effort has evidently borne fruit , as the promotion rates for O-5 and O-6 Space Cadre members has been generally slightly higher

  7. A Global Soil Moisture Data Assimilation System for the USDA-FAS Crop Assessment Data Retrieval and Evaluation (CADRE) Decision Support System

    USDA-ARS?s Scientific Manuscript database

    An Ensemble Kalman Filter (EnKF) system has been designed to integrate soil moisture retrievals from the EOS Advanced Microwave Scanning Radiometer (AMSR-E) into the U.S. Department of Agriculture (USDA) Crop Assessment Data Retrieval and Evaluation (CADRE) Decision Support System (DSS). The operati...

  8. Determination of the Clean Air Delivery Rate (CADR) of Photocatalytic Oxidation (PCO) Purifiers for Indoor Air Pollutants Using a Closed-Loop Reactor. Part II: Experimental Results.

    PubMed

    Héquet, Valérie; Batault, Frédéric; Raillard, Cécile; Thévenet, Frédéric; Le Coq, Laurence; Dumont, Éric

    2017-03-06

    The performances of a laboratory PhotoCatalytic Oxidation (PCO) device were determined using a recirculation closed-loop pilot reactor. The closed-loop system was modeled by associating equations related to two ideal reactors: a perfectly mixed reservoir with a volume of VR = 0.42 m³ and a plug flow system corresponding to the PCO device with a volume of VP = 5.6 × 10(-3) m³. The PCO device was composed of a pleated photocatalytic filter (1100 cm²) and two 18-W UVA fluorescent tubes. The Clean Air Delivery Rate (CADR) of the apparatus was measured under different operating conditions. The influence of three operating parameters was investigated: (i) light irradiance I from 0.10 to 2.0 mW·cm(-2); (ii) air velocity v from 0.2 to 1.9 m·s(-1); and (iii) initial toluene concentration C₀ (200, 600, 1000 and 4700 ppbv). The results showed that the conditions needed to apply a first-order decay model to the experimental data (described in Part I) were fulfilled. The CADR values, ranging from 0.35 to 3.95 m³·h(-1), were mainly dependent on the light irradiance intensity. A square root influence of the light irradiance was observed. Although the CADR of the PCO device inserted in the closed-loop reactor did not theoretically depend on the flow rate (see Part I), the experimental results did not enable the confirmation of this prediction. The initial concentration was also a parameter influencing the CADR, as well as the toluene degradation rate. The maximum degradation rate rmax ranged from 342 to 4894 ppbv/h. Finally, this study evidenced that a recirculation closed-loop pilot could be used to develop a reliable standard test method to assess the effectiveness of PCO devices.

  9. Measuring Radiant Emissions from Entire Prescribed Fires with Ground, Airborne and Satellite Sensors RxCADRE 2012

    NASA Technical Reports Server (NTRS)

    Dickinson, Matthew B.; Hudak, Andrew T.; Zajkowski, Thomas; Loudermilk, E. Louise; Schroeder, Wilfrid; Ellison, Luke; Kremens, Robert L.; Holley, William; Martinez, Otto; Paxton, Alexander; hide

    2015-01-01

    Characterising radiation from wildland fires is an important focus of fire science because radiation relates directly to the combustion process and can be measured across a wide range of spatial extents and resolutions. As part of a more comprehensive set of measurements collected during the 2012 Prescribed Fire Combustion and Atmospheric Dynamics Research (RxCADRE) field campaign, we used ground, airborne and spaceborne sensors to measure fire radiative power (FRP) from whole fires, applying different methods to small (2 ha) and large (.100 ha) burn blocks. For small blocks (n1/46), FRP estimated from an obliquely oriented long-wave infrared (LWIR) camera mounted on a boom lift were compared with FRP derived from combined data from tower-mounted radiometers and remotely piloted aircraft systems (RPAS). For large burn blocks (n1/43), satellite FRP measurements from the Moderate-resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) sensors were compared with near-coincident FRP measurements derived from a LWIR imaging system aboard a piloted aircraft. We describe measurements and consider their strengths and weaknesses. Until quantitative sensors exist for small RPAS, their use in fire research will remain limited. For oblique, airborne and satellite sensors, further FRP measurement development is needed along with greater replication of coincident measurements, which we show to be feasible.

  10. Measuring Radiant Emissions from Entire Prescribed Fires with Ground, Airborne and Satellite Sensors RxCADRE 2012

    NASA Technical Reports Server (NTRS)

    Dickinson, Matthew B.; Hudak, Andrew T.; Zajkowski, Thomas; Loudermilk, E. Louise; Schroeder, Wilfrid; Ellison, Luke; Kremens, Robert L.; Holley, William; Martinez, Otto; Paxton, Alexander; Bright, Benjamin C.; O'Brien, Joseph J.; Hornsby, Benjamin; Ichoku, Charles; Faulring, Jason; Gerace, Aaron; Peterson, David; Mauceri, Joseph

    2015-01-01

    Characterising radiation from wildland fires is an important focus of fire science because radiation relates directly to the combustion process and can be measured across a wide range of spatial extents and resolutions. As part of a more comprehensive set of measurements collected during the 2012 Prescribed Fire Combustion and Atmospheric Dynamics Research (RxCADRE) field campaign, we used ground, airborne and spaceborne sensors to measure fire radiative power (FRP) from whole fires, applying different methods to small (2 ha) and large (.100 ha) burn blocks. For small blocks (n1/46), FRP estimated from an obliquely oriented long-wave infrared (LWIR) camera mounted on a boom lift were compared with FRP derived from combined data from tower-mounted radiometers and remotely piloted aircraft systems (RPAS). For large burn blocks (n1/43), satellite FRP measurements from the Moderate-resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) sensors were compared with near-coincident FRP measurements derived from a LWIR imaging system aboard a piloted aircraft. We describe measurements and consider their strengths and weaknesses. Until quantitative sensors exist for small RPAS, their use in fire research will remain limited. For oblique, airborne and satellite sensors, further FRP measurement development is needed along with greater replication of coincident measurements, which we show to be feasible.

  11. A longitudinal study assessing the maintenance condition of cadres of four types of wheelchairs provided in low-resource areas.

    PubMed

    Rispin, Karen; Riseling, Kristofer; Wee, Joy

    2017-03-22

    Wheelchair breakdowns increase the risk of injury and limit the mobility of wheelchair users. In the endeavour to meet the enormous global need for wheelchairs, manufacturers of wheelchairs for low-resource settings face a cost-benefit tension between affordability and durability. Field studies are needed to provide feedback on durability. Four manufacturers provided cadres of wheelchairs to the organization providing rehabilitation to students at a boarding school for children with disabilities in a low-resource area. The Wheelchair Components Questionnaire for Condition was used to evaluate wheelchair maintenance condition at several time intervals after fitting. Because the maintenance regime was not identical for the four wheelchair types, wheelchair types were not compared. Analysis of variance indicated differences in condition across time and between wheelchair components. Tukey's simultaneous comparison of means indicated that across the entire group, brakes, seats, casters and foot rests received lower ratings than frame. Preliminary data after each iteration of this study were provided to manufactures and resulted in responsive design changes. Implications for Rehabilitation Longitudinal studies with the Wheelchair Components Questionnaire for Condition (WCQc) have enabled manufacturers to make responsive design improvements. Additional studies could be done with other wheelchair types to result in responsive positive design changes for those wheelchairs as well. The WCQc can be used in studies on wheelchair condition even when records of repair history are not reliably available, a situation which is not uncommon in low-resource areas. Data sets collected at an individual clinic uses the WCQc could focus attention on wheelchair components needing regular repair. With that data in mind, the maintenance regime could be modified to respond and in so doing improve wheelchair condition and reduce loss of mobility or risk of injury. Organizations involved in

  12. Rural recruitment and retention of health workers across cadres and types of contract in north-east India: A qualitative study.

    PubMed

    Rajbangshi, Preety R; Nambiar, Devaki; Choudhury, Nandini; Rao, Krishna D

    2017-09-01

    Background Like many other low- and middle-income countries, India faces challenges of recruiting and retaining health workers in rural areas. Efforts have been made to address this through contractual appointment of health workers in rural areas. While this has helped to temporarily bridge the gaps in human resources, the overall impact on the experience of rural services across cadres has yet to be understood. This study sought to identify motivations for, and the challenges of, rural recruitment and retention of nurses, doctors and specialists across types of contract in rural and remote areas in India's largely rural north-eastern states of Meghalaya and Nagaland. Methods A qualitative study was undertaken, in which 71 semi-structured interviews were carried out with doctors (n = 32), nurses (n = 28) and specialists (n = 11). In addition, unstructured key informant interviews (n = 11) were undertaken, along with observations at health facilities and review of state policies. Data were analysed using Ritchie and Spencer's framework method and the World Health Organization's 2010 framework of factors affecting decisions to relocate to, stay in or leave rural areas. Results It was found that rural background and community attachment were strongly associated with health workers' decision to join rural service, regardless of cadre or contract. However, this aspiration was challenged by health-systems factors of poor working and living conditions; low salary and incentives; and lack of professional growth and recognition. Contractual health workers faced unique challenges (lack of pay parity, job insecurity), as did those with permanent positions (irrational postings and political interference). Conclusion This study establishes that the crisis in recruiting and retaining health workers in rural areas will persist until and unless health systems address the core basic requirements of health workers in rural areas, which are related to health-sector policies

  13. Does child and adolescent mental health in-service training result in equivalent knowledge gain among cadres of non-specialist health workers in Uganda? A pre-test post-test study.

    PubMed

    Akol, Angela; Nalugya, Joyce; Nshemereirwe, Sylvia; Babirye, Juliet N; Engebretsen, Ingunn Marie Stadskleiv

    2017-01-01

    Early identification and management of child and adolescent mental health (CAMH) disorders helps to avert mental illness in adulthood but a CAMH treatment gap exists in Uganda. CAMH integration into primary health care (PHC) through in-service training of non-specialist health workers (NSHW) using the World Health Organisation (WHO) Mental Health Gap Action Programme (mhGAP) Intervention Guide (IG) is a strategy to address this gap. However, results of such training are not supported by information on training development or delivery; and are undifferentiated by NSHW cadre. We aim to describe an in-service CAMH training for NSHW in Uganda and assess cadre-differentiated learning outcomes. Thirty-six clinical officers, nurses and midwives from 18 randomly selected PHC clinics in eastern Uganda were trained for 5 days on CAMH screening and referral using a curriculum based on the mhGAP-IG version 1.0 and PowerPoint slides from the International Association of Child and Adolescent Psychiatry and Allied Professions (IACAPAP). The residential training was evaluated through pre- and post- training tests of CAMH knowledge and attitudes using the participants' post-test scores; and the difference between pre-test and post-test scores. Two-tailed t-tests assessed differences in mean pre-test and post-test scores between the cadres; hierarchical linear regression tested the association between cadre and post test scores; and logistic regression evaluated the relationship between cadre and knowledge gain at three pre-determined cut off points. Thirty-three participants completed both pre-and post-tests. Improved mean scores from pre- to post-test were observed for both clinical officers (20% change) and nurse/midwives (18% change). Clinical officers had significantly higher mean test scores than nurses and midwives (p < 0.05) but cadre was not significantly associated with improvement in CAMH knowledge at the 10% (AOR 0.08; 95 CI [0.01, 1.19]; p = 0.066), 15% (AOR 0

  14. Pre-event Smallpox Vaccination for Healthcare Workers Revisited – the Need for a Carefully Screened Multidisciplinary Cadre

    SciTech Connect

    Malone, JD D.

    2007-03-01

    Abstract As healthcare institutions are a focus of smallpox transmission early in an epidemic, several mathematical models support pre-event smallpox vaccination of healthcare workers (HCWs). The deciding factor for HCW voluntary vaccination is the risk of disease exposure versus the risk of vaccine adverse events. In a United States military population, with careful screening to exclude atopic dermatitis/eczema and immunosuppression, over 1 million vaccinia vaccinations were delivered with 1 fatality attributed to vaccination. Among 37,901 U.S. civilian volunteer healthcare workers vaccinated, 100 serious adverse events were reported including 10 ischemic cardiac episodes and six myocardial infarctions – 2 were fatal. This older population had a higher rate of adverse events due to age related coronary artery disease. T-cell mediated inflammatory processes, induced by live vaccinia vaccination, may have a role in the observed acute coronary artery events. With exclusion of individuals at risk for coronary artery disease, atopic dermatitis/eczema, and immunosuppression, HCWs can be smallpox vaccinated with minimal risk. A smallpox pre-vaccinated multidisciplinary cadre (physician, nurse, infection control practitioner, technician) will supply leadership to deal with fear and uncertainty while limiting spread and initial mortality of smallpox. Stochastic – from the Greek meaning “skillful in aiming” – is currently interpreted as arising from chance and involving probability. This issue’s article “Containing a large bioterrorist smallpox attack: a computer simulation approach” by Longini et al. is a discrete time, stochastic computer simulation model that offers additional planning guidance for a smallpox (variola virus) outbreak (1). Although interpretation of the model’s information may differ, Longini’s article concludes “Given that surveillance and containment measures are in place, preemptive vaccination of hospital workers would further

  15. COHORT Cadre Training Evaluation

    DTIC Science & Technology

    1987-05-11

    Officers/ COW rRt- Unit Manning System) • Z. A ?ST-RACT (’rCmtL=am F* vwrae mica it nfcV’ea" a*= Iden tr, by block numb .,’ This report provides data and...TASKS? ___L1VEL OF CONFIDENE DO NOTITASK gone Ve~y- LOW cow High Very -Hi-gh AbsoUt PERFOSMTHIS TASK _23-. Prepare Driver’s Station for Opera- tion on...40 18 Il3 SPH [ TVAIN[G 90 OsIdS [S 3 V MS LMUG AND 2 WU maB usApAs Amo asAARm. Au 4~ s jf N Table 4. Mug I UISeIECAL !3A3 MUMr &JSINUMn?* oso COW

  16. Cadres for Rural Schools.

    ERIC Educational Resources Information Center

    Iagofarova, D. S.

    1990-01-01

    Considers qualities required of rural teachers in the USSR and implications for teacher education. Reports survey results of 430 rural teachers in the Tatar region concerning what a rural teacher must know and problems specific to rural teaching. Concludes that rural teachers must coordinate teaching with social work and face housing and material…

  17. Determination of the Clean Air Delivery Rate (CADR) of Photocatalytic Oxidation (PCO) Purifiers for Indoor Air Pollutants Using a Closed-Loop Reactor. Part I: Theoretical Considerations.

    PubMed

    Dumont, Éric; Héquet, Valérie

    2017-03-06

    This study demonstrated that a laboratory-scale recirculation closed-loop reactor can be an efficient technique for the determination of the Clean Air Delivery Rate (CADR) of PhotoCatalytic Oxidation (PCO) air purification devices. The recirculation closed-loop reactor was modeled by associating equations related to two ideal reactors: one is a perfectly mixed reservoir and the other is a plug flow system corresponding to the PCO device itself. Based on the assumption that the ratio between the residence time in the PCO device and the residence time in the reservoir τP/τR tends to 0, the model highlights that a lab closed-loop reactor can be a suitable technique for the determination of the efficiency of PCO devices. Moreover, if the single-pass removal efficiency is lower than 5% of the treated flow rate, the decrease in the pollutant concentration over time can be characterized by a first-order decay model in which the time constant is proportional to the CADR. The limits of the model are examined and reported in terms of operating conditions (experiment duration, ratio of residence times, and flow rate ranges).

  18. The Mediating Role of Psychological Capital on the Association between Occupational Stress and Job Satisfaction among Township Cadres in a Specific Province of China: A Cross-Sectional Study.

    PubMed

    Guan, Chang-Yue Shang; Li, Yu; Ma, Hong-Lin

    2017-08-28

    Background: Township cadres, considered as basic executors of state policy, play an important role in Chinese society. Their job satisfaction is a vital issue for township management, but there are few studies on this topic in China. The goal of this study is to analyze the relationship between occupational stress and job satisfaction, and to further examine whether psychological capital (PsyCap) can serve as a mediator between stress and job satisfaction in Chinese township cadres. Methods: A cross-sectional survey was carried out during the period of from October 2015 to January 2016 in Liaoning Province of China. The questionnaires, which consisted of an effort-reward imbalance scale, Minnesota Satisfaction Questionnaire (MSQ) for job satisfaction, and the psychological capital questionnaire (PCQ-24), as well as questions about demographic characteristics, were distributed to 1800 township cadres and complete responses were received from 1525 participants. Structural equation modeling was used to examine the role that psychological capital played in mediating between occupational stress and job satisfaction. Results: In the present study, effort-reward ratio (ERR= 11 × effort/6 × reward) was negatively associated with job satisfaction (r = -0.372, p < 0.001), whereas psychological capital was positively associated with job satisfaction in township cadres (r = 0.587, p < 0.001) from a specific province in China. Psychological capital is a mediator between the association of job stress and job satisfaction. Conclusions: Psychological capital partially mediated the relationship between job stress and job satisfaction among Chinese township cadres. Interventions to improve Chinese township cadres' job satisfaction should be developed in the future, especially the enhancement of PsyCap. Interventions need to be verified in further cohort studies. At present, we are only proposing a theoretical model. Intervention effects need to be validated in further cohort

  19. Cadre conceptuel des programmes de francais a l'elementaire: lignes directrices (Conceptual Framework for Elementary School French Programs: Axes).

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Language Services Branch.

    The conceptual framework within which Alberta's elementary school French immersion programs are designed is presented. The first of three main sections outlines the evolution of the concept of language and some second language instructional approaches, including the structural, formalist, functional, and communicative approaches. It also discusses…

  20. Cadre conceptuel des programmes de francais a l'elementaire: lignes directrices (Conceptual Framework for Elementary School French Programs: Axes).

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Language Services Branch.

    The conceptual framework within which Alberta's elementary school French immersion programs are designed is presented. The first of three main sections outlines the evolution of the concept of language and some second language instructional approaches, including the structural, formalist, functional, and communicative approaches. It also discusses…

  1. The Mediating Role of Psychological Capital on the Association between Occupational Stress and Job Satisfaction among Township Cadres in a Specific Province of China: A Cross-Sectional Study

    PubMed Central

    Shang Guan, Chang-Yue; Li, Yu; Ma, Hong-Lin

    2017-01-01

    Background: Township cadres, considered as basic executors of state policy, play an important role in Chinese society. Their job satisfaction is a vital issue for township management, but there are few studies on this topic in China. The goal of this study is to analyze the relationship between occupational stress and job satisfaction, and to further examine whether psychological capital (PsyCap) can serve as a mediator between stress and job satisfaction in Chinese township cadres. Methods: A cross-sectional survey was carried out during the period of from October 2015 to January 2016 in Liaoning Province of China. The questionnaires, which consisted of an effort-reward imbalance scale, Minnesota Satisfaction Questionnaire (MSQ) for job satisfaction, and the psychological capital questionnaire (PCQ-24), as well as questions about demographic characteristics, were distributed to 1800 township cadres and complete responses were received from 1525 participants. Structural equation modeling was used to examine the role that psychological capital played in mediating between occupational stress and job satisfaction. Results: In the present study, effort-reward ratio (ERR= 11 × effort/6 × reward) was negatively associated with job satisfaction (r = −0.372, p < 0.001), whereas psychological capital was positively associated with job satisfaction in township cadres (r = 0.587, p < 0.001) from a specific province in China. Psychological capital is a mediator between the association of job stress and job satisfaction. Conclusions: Psychological capital partially mediated the relationship between job stress and job satisfaction among Chinese township cadres. Interventions to improve Chinese township cadres’ job satisfaction should be developed in the future, especially the enhancement of PsyCap. Interventions need to be verified in further cohort studies. At present, we are only proposing a theoretical model. Intervention effects need to be validated in further cohort

  2. Towards eliminating malaria in high endemic countries: the roles of community health workers and related cadres and their challenges in integrated community case management for malaria: a systematic review.

    PubMed

    Sunguya, Bruno F; Mlunde, Linda B; Ayer, Rakesh; Jimba, Masamine

    2017-01-03

    Human resource for health crisis has impaired global efforts against malaria in highly endemic countries. To address this, the World Health Organization (WHO) recommended scaling-up of community health workers (CHWs) and related cadres owing to their documented success in malaria and other disease prevention and management. Evidence is inconsistent on the roles and challenges they encounter in malaria interventions. This systematic review aims to summarize evidence on roles and challenges of CHWs and related cadres in integrated community case management for malaria (iCCM). This systematic review retrieved evidence from PubMed, CINAHL, ISI Web of Knowledge, and WHO regional databases. Terms extracted from the Boolean phrase used for PubMed were also used in other databases. The review included studies with Randomized Control Trial, Quasi-experimental, Pre-post interventional, Longitudinal and cohort, Cross-sectional, Case study, and Secondary data analysis. Because of heterogeneity, only narrative synthesis was conducted for this review. A total of 66 articles were eligible for analysis out of 1380 studies retrieved. CHWs and related cadre roles in malaria interventions included: malaria case management, prevention including health surveillance and health promotion specific to malaria. Despite their documented success, CHWs and related cadres succumb to health system challenges. These are poor and unsustainable finance for iCCM, workforce related challenges, lack of and unsustainable supply of medicines and diagnostics, lack of information and research, service delivery and leadership challenges. Community health workers and related cadres had important preventive, case management and promotive roles in malaria interventions. To enable their effective integration into the health systems, the identified challenges should be addressed. They include: introducing sustainable financing on iCCM programmes, tailoring their training to address the identified gaps

  3. Teaching Evolution

    ERIC Educational Resources Information Center

    Bryner, Jeanna

    2005-01-01

    Eighty years after the famous 1925 Scopes "monkey trial," which tested a teacher's right to discuss the theory of evolution in the classroom, evolution--and its most recent counterview, called "intelligent design"--are in the headlines again, and just about everyone seems to have an opinion. This past July, President Bush weighed in, telling…

  4. FTS evolution

    NASA Technical Reports Server (NTRS)

    Provost, David E.

    1990-01-01

    Viewgraphs on flight telerobotic servicer evolution are presented. Topics covered include: paths for FTS evolution; frequently performed actions; primary task states; EPS radiator panel installation; generic task definitions; path planning; non-contact alignment; contact planning and control; and human operator interface.

  5. FTS evolution

    NASA Technical Reports Server (NTRS)

    Provost, David E.

    1990-01-01

    Viewgraphs on flight telerobotic servicer evolution are presented. Topics covered include: paths for FTS evolution; frequently performed actions; primary task states; EPS radiator panel installation; generic task definitions; path planning; non-contact alignment; contact planning and control; and human operator interface.

  6. Perception de la verticale avec Un cadre visuel solidaire de la tete: implications pour la conception des afficheurs de casques en ae’ronauflque (Perception of the Vertical With a Head-Mounted Visual Frame: Implication for the Design of Helmet-Mounted Displays in Aeronautics)

    DTIC Science & Technology

    2003-02-01

    leurs changements d’orientation. L’orientation du cadre solidaire de la tete ne peut etre 6valude que sur la base des signaux de position de la tete...r6fdrentiel c6phalocentr6 sont inexistantes. Au contraire, lorsque lorientation du cadre est dissoci6e de celle de la tete, toute rotation peut etre ...rapport it la tete peuvent etre prises en compte en conjonction avec les signaux vestibulaires et proprioceptifs qui renseignent sur lorientation de la

  7. Stellar evolution.

    NASA Technical Reports Server (NTRS)

    Chiu, H.-Y. (Editor); Muriel, A.

    1972-01-01

    Aspects of normal stellar evolution are discussed together with evolution near the main sequence, stellar evolution from main sequence to white dwarf or carbon ignition, the structure of massive main-sequence stars, and problems of stellar stability and stellar pulsation. Other subjects considered include variable stars, white dwarfs, close binaries, novae, early supernova luminosity, neutron stars, the photometry of field horizontal-branch stars, and stellar opacity. Transport mechanisms in stars are examined together with thermonuclear reactions and nucleosynthesis, the instability problem in nuclear burning shells, stellar coalescence, and intense magnetic fields in astrophysics. Individual items are announced in this issue.

  8. Simulating Evolution

    ERIC Educational Resources Information Center

    Stebbins, Robert C.; Allen, Brockenbrough

    1975-01-01

    Described are simulations that can be used to illustrate evolution by natural selection. Suggestions for simulating phenomena such as adaptive radiation, color match to background and vision of predators are offered. (BR)

  9. Experimental evolution.

    PubMed

    Kawecki, Tadeusz J; Lenski, Richard E; Ebert, Dieter; Hollis, Brian; Olivieri, Isabelle; Whitlock, Michael C

    2012-10-01

    Experimental evolution is the study of evolutionary processes occurring in experimental populations in response to conditions imposed by the experimenter. This research approach is increasingly used to study adaptation, estimate evolutionary parameters, and test diverse evolutionary hypotheses. Long applied in vaccine development, experimental evolution also finds new applications in biotechnology. Recent technological developments provide a path towards detailed understanding of the genomic and molecular basis of experimental evolutionary change, while new findings raise new questions that can be addressed with this approach. However, experimental evolution has important limitations, and the interpretation of results is subject to caveats resulting from small population sizes, limited timescales, the simplified nature of laboratory environments, and, in some cases, the potential to misinterpret the selective forces and other processes at work. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Security Evolution.

    ERIC Educational Resources Information Center

    De Patta, Joe

    2003-01-01

    Examines how to evaluate school security, begin making schools safe, secure schools without turning them into fortresses, and secure schools easily and affordably; the evolution of security systems into information technology systems; using schools' high-speed network lines; how one specific security system was developed; pros and cons of the…

  11. Art & Evolution

    ERIC Educational Resources Information Center

    Terry, Mark

    2005-01-01

    In this article, the author presents a two-week evolution unit for his biology class. He uses Maria Sybilla Merian (1647-1717) as an example of an Enlightenment mind at work--in this case a woman recognized as one of the great artists and natural scientists of her time. Her representations of butterflies, caterpillars and their pupae, and the…

  12. Silent evolution

    PubMed Central

    OSAWA, Syozo; SU, Zhi-Hui; NISHIKAWA, Masaaki; TOMINAGA, Osamu

    2016-01-01

    Phylogenetic analyses using mitochondrial DNA sequences of several kinds of beetles have shown that their evolution included a silent stage in which no morphological changes took place. We thus propose a new category of evolutionary process called “silent evolution”. PMID:27840392

  13. Art & Evolution

    ERIC Educational Resources Information Center

    Terry, Mark

    2005-01-01

    In this article, the author presents a two-week evolution unit for his biology class. He uses Maria Sybilla Merian (1647-1717) as an example of an Enlightenment mind at work--in this case a woman recognized as one of the great artists and natural scientists of her time. Her representations of butterflies, caterpillars and their pupae, and the…

  14. Equatorial Dynamics Observed by Rocket, Radar, and Satellite During the CADRE/MALTED Campaign. 1; Programmatics and small-scale fluctuations

    NASA Technical Reports Server (NTRS)

    Goldberg, Richard A.; Lehmacher, Gerald A.; Schmidlin, Frank J.; Fritts, David C.; Mitchell, J. D.; Croskey, C. L.; Friedrich, M.; Swartz, W. E.

    1997-01-01

    In August 1994, the Mesospheric and Lower Thermospheric Equatorial Dynamics (MALTED) Program was conducted from the Alcantara rocket site in northeastern Brazil as part of the International Guard Rocket Campaign to study equatorial dynamics, irregularities, and instabilities in the ionosphere. This site was selected because of its proximity to the geographic (2.3 deg S) and magnetic (approx. 0.5 deg S) equators. MALTED was concerned with planetary wave modulation of the diurnal tidal amplitude, which exhibits considerable amplitude variability at equatorial and subtropical latitudes. Our goals were to study this global modulation of the tidal motions where tidal influences on the thermal structure are maximum, to study the interaction of these tidal structures with gravity waves and turbulence at mesopause altitudes, and to gain a better understanding of dynamic influences and variability on the equatorial middle atmosphere. Four (two daytime and two nighttime) identical Nike-Orion payloads designed to investigate small-scale turbulence and irregularities were coordinated with 20 meteorological falling-sphere rockets designed to measure temperature and wind fields during a 10-day period. These in situ measurements were coordinated with observations of global-scale mesospheric motions that were provided by various ground based radars and the Upper Atmosphere Research Satellite (UARS) through the Coupling and Dynamics of Regions Equatorial (CADRE) campaign. The ground-based observatories included the Jicamarca radar observatory near Lima, Peru, and medium frequency (MF) radars in Hawaii, Christmas Island, and Adelaide. Since all four Nike-Orion flights penetrated and overflew the electrojet with apogees near 125 km, these flights provided additional information about the electrodynamics and irregularities in the equatorial ionospheric E region and may provide information on wave coupling between the mesosphere and the electrojet. Simultaneous with these flights, the

  15. Equatorial dynamics observed by rocket, radar, and satellite during the CADRE/MALTED campaign 1. Programmatics and small-scale fluctuations

    NASA Astrophysics Data System (ADS)

    Goldberg, Richard A.; Lehmacher, Gerald A.; Schmidlin, Frank J.; Fritts, David C.; Mitchell, J. D.; Croskey, C. L.; Friedrich, M.; Swartz, W. E.

    1997-11-01

    In August 1994, the Mesospheric and Lower Thermospheric Equatorial Dynamics (MALTED) Program was conducted from the Alca‸ntara rocket site in northeastern Brazil as part of the International Guará Rocket Campaign to study equatorial dynamics, irregularities, and instabilities in the ionosphere. This site was selected because of its proximity to the geographic (2.3°S) and magnetic (~0.5°S) equators. MALTED was concerned with planetary wave modulation of the diurnal tidal amplitude, which exhibits considerable amplitude variability at equatorial and subtropical latitudes. Our goals were to study this global modulation of the tidal motions where tidal influences on the thermal structure are maximum, to study the interaction of these tidal structures with gravity waves and turbulence at mesopause altitudes, and to gain a better understanding of dynamic influences and variability on the equatorial middle atmosphere. Four (two daytime and two nighttime) identical Nike-Orion payloads designed to investigate small-scale turbulence and irregularities were coordinated with 20 meteorological falling-sphere rockets designed to measure temperature and wind fields during a 10-day period. These in situ measurements were coordinated with observations of global-scale mesospheric motions that were provided by various ground based radars and the Upper Atmosphere Research Satellite (UARS) through the Coupling and Dynamics of Regions Equatorial (CADRE) campaign. The ground-based observatories included the Jicamarca radar observatory near Lima, Peru, and medium frequency (MF) radars in Hawaii, Christmas Island, and Adelaide. Since all four Nike-Orion flights penetrated and overflew the electrojet with apogees near 125 km, these flights provided additional information about the electrodynamics and irregularities in the equatorial ionospheric E region and may provide information on wave coupling between the mesosphere and the electrojet. Simultaneous with these flights, the CUPRI 50

  16. Profile, knowledge, and work patterns of a cadre of maternal, newborn, and child health CHWs focusing on preventive and promotive services in Morogoro Region, Tanzania.

    PubMed

    LeFevre, Amnesty E; Mpembeni, Rose; Chitama, Dereck; George, Asha S; Mohan, Diwakar; Urassa, David P; Gupta, Shivam; Feldhaus, Isabelle; Pereira, Audrey; Kilewo, Charles; Chebet, Joy J; Cooper, Chelsea M; Besana, Giulia; Lutale, Harriet; Bishanga, Dunstan; Mtete, Emmanuel; Semu, Helen; Baqui, Abdullah H; Killewo, Japhet; Winch, Peter J

    2015-12-24

    Despite impressive decreases in under-five mortality, progress in reducing maternal and neonatal mortality in Tanzania has been slow. We present an evaluation of a cadre of maternal, newborn, and child health community health worker (MNCH CHW) focused on preventive and promotive services during the antenatal and postpartum periods in Morogoro Region, Tanzania. Study findings review the effect of several critical design elements on knowledge, time allocation, service delivery, satisfaction, and motivation. A quantitative survey on service delivery and knowledge was administered to 228 (of 238 trained) MNCH CHWs. Results are compared against surveys administered to (1) providers in nine health centers (n = 88) and (2) CHWs (n = 53) identified in the same districts prior to the program's start. Service delivery outputs were measured by register data and through a time motion study conducted among a sub-sample of 33 randomly selected MNCH CHWs. Ninety-seven percent of MNCH CHWs (n = 228) were interviewed: 55% male, 58% married, and 52% with secondary school education or higher. MNCH CHWs when compared to earlier CHWs were more likely to be unmarried, younger, and more educated. Mean MNCH CHW knowledge scores were <50% for 8 of 10 MNCH domains assessed and comparable to those observed for health center providers but lower than those for earlier CHWs. MNCH CHWs reported covering a mean of 186 households and were observed to provide MNCH services for 5 h weekly. Attendance of monthly facility-based supervision meetings was nearly universal and focused largely on registers, yet data quality assessments highlighted inconsistencies. Despite program plans to provide financial incentives and bicycles for transport, only 56% of CHWs had received financial incentives and none received bicycles. Initial rollout of MNCH CHWs yields important insights into addressing program challenges. The social profile of CHWs was not significantly associated with knowledge or

  17. Cryptococcal antigen screening by lay cadres using a rapid test at the point of care: A feasibility study in rural Lesotho.

    PubMed

    Rick, Fernanda; Niyibizi, Aline Aurore; Shroufi, Amir; Onami, Kazumi; Steele, Sarah-Jane; Kuleile, Malehlohonolo; Muleya, Innocent; Chiller, Tom; Walker, Tiffany; Van Cutsem, Gilles

    2017-01-01

    referral to hospital for symptomatic cases, proved feasible. However, regular follow-up to ensure proper management of cryptococcal disease was needed. These early results support the wider use of CrAg LFA screening in remote primary care settings where upper cadres of healthcare staff may be in short supply.

  18. Considering a Cadre Augmented Army

    DTIC Science & Technology

    2008-01-01

    156 Asch and Warner (2001), p. 1 157 This was the lump-sum payment (SSB) offered to E-5 personnel with ten years of experience during...the Cold War drawdown [ Asch and Warner (2001), p.5]. 158 This is the fraction of Air Force personnel that were offered separation incentives in 1992...relative to the size of the planned end-strength reduction for the Air Force. [ Asch and Warner (2001), p. 7, 19] Similar information was not

  19. Cadre conceptuel des programmes de francais au secondaire: lignes directrices. Immersion (Conceptual Framework for French Programs at the Secondary Level: Guidelines. Immersion).

    ERIC Educational Resources Information Center

    Bourque, Francine; And Others

    Conceptual guidelines for the design of new secondary school French second language programs are outlined, in response to the need for an instructional model to accommodate Alberta's increasing anglophone enrollment in French immersion programs. The first section chronicles the evolution of the concept of language and second language instructional…

  20. Public Safety Technical Program Planning Scenario Framework Final Report (Rapport Final sur le Cadre de Creation de Scenarios de Planification du Programme Technique de Securite Publique)

    DTIC Science & Technology

    2010-12-01

    analysis can be included. The term vignette, meaning “little vine”, is derived from theatre script and poetry . Vignettes are short, impressionistic...mitigation to recovery. • Should cover all classes of users, and built for continued expansion through ready access and evolution. This should include

  1. Insect evolution.

    PubMed

    Engel, Michael S

    2015-10-05

    It goes without saying that insects epitomize diversity, and with over a million documented species they stand out as one of the most remarkable lineages in the 3.5-billion-year history of life on earth (Figure 1). This reality is passé to even the layperson and is taken for granted in the same way none of us think much of our breathing as we go about our day, and yet insects are just as vital to our existence. Insects are simultaneously familiar and foreign to us, and while a small fraction are beloved or reviled, most are simply ignored. These inexorable evolutionary overachievers outnumber us all, their segmented body plan is remarkably labile, they combine a capacity for high rates of speciation with low levels of natural extinction, and their history of successes eclipses those of the more familiar ages of dinosaurs and mammals alike. It is their evolution - persisting over vast expanses of geological time and inextricably implicated in the diversification of other lineages - that stands as one of the most expansive subjects in biology.

  2. EMU evolution

    NASA Technical Reports Server (NTRS)

    Rouen, M.

    1991-01-01

    Evolution of Extravehicular Mobility Unit (EMU) technology is necessary to support the Extravehicular Activity (EVA) requirements of the Space Station Freedom Program and those of the Space Exploration Initiative (SEI). Key qualities supporting long-duration missions include technologies that are highly reliable, durable, minimize logistics requirements, and are in-flight maintainable and serviceable. While these qualities are common to SSF and SEI EVA, development paths will differ where specific mission requirements impose different constraints. Development of reusable, regenerative technologies is necessary to minimize the logistics penalties. Increased battery discharge/recharge cycle life and usable wet life, compact high current density fuel cells, reusable CO2 absorbing media, and thermal radiation coupled with venting heat rejection technologies are just some methods of reducing consumables. Development must strive for durable, reliable systems that are in-flight serviceable and maintainable, which are vital for missions where logistics capabilities are extremely constrained. Key areas include suit components (e.g., gloves, boots, and cooling garments), and life support hardware such as fans, pumps, instrumentation, and emergency O2 systems. Higher pressure suits will reduce EVA prebreathe requirements and pre-EVA operations overall. Many challenges of higher pressure suits have been addressed by on-going development. Emphasis on glove development is necessary to provide low fatigue, dexterous glove mobility at higher suit pressures. Minimum impact hooks and scars which support an advanced SSF EMU have been identified. These accommodations permit upgrades that support servicing of low volume, high pressure oxygen systems, and hydrogen technologies such as fuel cell, and venting hydrogen heat rejection systems.

  3. Evolution: Help for the Confused.

    ERIC Educational Resources Information Center

    Scheer, Bradley T.

    1979-01-01

    Written in response to an earlier article questioning certain aspects of evolution theory. Discusses ontogeny and phylogeny, the basis of evolution, chance or purpose in evolution, micro and macro-evolution, reversibility, and the evolution processes today. (MA)

  4. Evolution: Help for the Confused.

    ERIC Educational Resources Information Center

    Scheer, Bradley T.

    1979-01-01

    Written in response to an earlier article questioning certain aspects of evolution theory. Discusses ontogeny and phylogeny, the basis of evolution, chance or purpose in evolution, micro and macro-evolution, reversibility, and the evolution processes today. (MA)

  5. Secular Evolution of Galaxies

    NASA Astrophysics Data System (ADS)

    Falcón-Barroso, Jesús; Knapen, Johan H.

    2013-10-01

    Preface; 1. Secular evolution in disk galaxies John Kormendy; 2. Galaxy morphology Ronald J. Buta; 3. Dynamics of secular evolution James Binney; 4. Bars and secular evolution in disk galaxies: theoretical input E. Athanassoula; 5. Stellar populations Reynier F. Peletier; 6. Star formation rate indicators Daniela Calzetti; 7. The evolving interstellar medium Jacqueline van Gorkom; 8. Evolution of star formation and gas Nick Z. Scoville; 9. Cosmological evolution of galaxies Isaac Shlosman.

  6. Chemodiversity in Selaginella: a reference system for parallel and convergent metabolic evolution in terrestrial plants

    PubMed Central

    Weng, Jing-Ke; Noel, Joseph P.

    2013-01-01

    Early plants began colonizing the terrestrial earth approximately 450 million years ago. Their success on land has been partially attributed to the evolution of specialized metabolic systems from core metabolic pathways, the former yielding structurally and functionally diverse chemicals to cope with a myriad of biotic and abiotic ecological pressures. Over the past two decades, functional genomics, primarily focused on flowering plants, has begun cataloging the biosynthetic players underpinning assorted classes of plant specialized metabolites. However, the molecular mechanisms enriching specialized metabolic pathways during land plant evolution remain largely unexplored. Selaginella is an extant lycopodiophyte genus representative of an ancient lineage of tracheophytes. Notably, the lycopodiophytes diverged from euphyllophytes over 400 million years ago. The recent completion of the whole-genome sequence of an extant lycopodiophyte, S. moellendorffii, provides new genomic and biochemical resources for studying metabolic evolution in vascular plants. 400 million years of independent evolution of lycopodiophytes and euphyllophytes resulted in numerous metabolic traits confined to each lineage. Surprisingly, a cadre of specialized metabolites, generally accepted to be restricted to seed plants, have been identified in Selaginella. Initial work suggested that Selaginella lacks obvious catalytic homologs known to be involved in the biosynthesis of well-studied specialized metabolites in seed plants. Therefore, these initial functional analyses suggest that the same chemical phenotypes arose independently more commonly than anticipated from our conventional understanding of the evolution of metabolism. Notably, the emergence of analogous and homologous catalytic machineries through convergent and parallel evolution, respectively, seems to have occurred repeatedly in different plant lineages. PMID:23717312

  7. Understanding Evolution: An Evolution Website for Teachers

    ERIC Educational Resources Information Center

    Scotchmoor, Judy; Janulaw, Al

    2005-01-01

    While many states are facing challenges to the teaching of evolution in their science classrooms, the University of California Museum of Paleontology, working with the National Center for Science Education, has developed a useful web-based resource for science teachers of all grade- and experience-levels. Understanding Evolution (UE) was developed…

  8. Understanding Evolution: An Evolution Website for Teachers

    ERIC Educational Resources Information Center

    Scotchmoor, Judy; Janulaw, Al

    2005-01-01

    While many states are facing challenges to the teaching of evolution in their science classrooms, the University of California Museum of Paleontology, working with the National Center for Science Education, has developed a useful web-based resource for science teachers of all grade- and experience-levels. Understanding Evolution (UE) was developed…

  9. Perspective: reverse evolution.

    PubMed

    Teotónio, H; Rose, M R

    2001-04-01

    For some time, the reversibility of evolution was primarily discussed in terms of comparative patterns. Only recently has this problem been studied using experimental evolution over shorter evolutionary time frames. This has raised questions of definition, experimental procedure, and the hypotheses being tested. Experimental evolution has provided evidence for multiple population genetic mechanisms in reverse evolution, including pleiotropy and mutation accumulation. It has also pointed to genetic factors that might prevent reverse evolution, such as a lack of genetic variability, epistasis, and differential genotype-by-environment interactions. The main focus of this perspective is on laboratory studies and their relevance to the genetics of reverse evolution. We discuss reverse evolution experiments with Drosophila, bacterial, and viral populations. Field studies of the reverse evolution of melanism in the peppered moth are also reviewed.

  10. The Evolution of Design

    ERIC Educational Resources Information Center

    Stebbins, G. Ledyard

    1973-01-01

    Describes the basic logic behind the modern view of evolution theory. Despite gaps in fossil records, evidence is indicative of the origin of life from nonliving molecules and evolution of higher forms of life from simpler forms. (PS)

  11. The Evolution of Design

    ERIC Educational Resources Information Center

    Stebbins, G. Ledyard

    1973-01-01

    Describes the basic logic behind the modern view of evolution theory. Despite gaps in fossil records, evidence is indicative of the origin of life from nonliving molecules and evolution of higher forms of life from simpler forms. (PS)

  12. Mistakes and Molecular Evolution.

    ERIC Educational Resources Information Center

    Trevors, J. T.

    1998-01-01

    Examines the role mistakes play in the molecular evolution of bacteria. Discusses the interacting physical, chemical, and biological factors that cause changes in DNA and play a role in prokaryotic evolution. (DDR)

  13. Mistakes and Molecular Evolution.

    ERIC Educational Resources Information Center

    Trevors, J. T.

    1998-01-01

    Examines the role mistakes play in the molecular evolution of bacteria. Discusses the interacting physical, chemical, and biological factors that cause changes in DNA and play a role in prokaryotic evolution. (DDR)

  14. Evolution and Probability.

    ERIC Educational Resources Information Center

    Bailey, David H.

    2000-01-01

    Some of the most impressive-sounding criticisms of the conventional theory of biological evolution involve probability. Presents a few examples of how probability should and should not be used in discussing evolution. (ASK)

  15. Oxygen and Biological Evolution.

    ERIC Educational Resources Information Center

    Baugh, Mark A.

    1990-01-01

    Discussed is the evolution of aerobic organisms from anaerobic organisms and the accompanying biochemistry that developed to motivate and enable this evolution. Uses of oxygen by aerobic organisms are described. (CW)

  16. Oxygen and Biological Evolution.

    ERIC Educational Resources Information Center

    Baugh, Mark A.

    1990-01-01

    Discussed is the evolution of aerobic organisms from anaerobic organisms and the accompanying biochemistry that developed to motivate and enable this evolution. Uses of oxygen by aerobic organisms are described. (CW)

  17. HIV Evolution and Escape.

    PubMed Central

    Richman, Douglas D.; Little, Susan J.; Smith, Davey M.; Wrin, Terri; Petropoulos, Christos; Wong, Joseph K.

    2004-01-01

    Human immunodeficiency virus (HIV) exemplifies the principles of Darwinian evolution with a telescoped chronology. Because of its high mutation rate and remarkably high rates of replication, evolution can be appreciated over periods of days in contrast to the durations conceived of by Darwin. Certain selective pressures that drive the evolution of HIV include chemotherapy, anatomic compartmentalization and the immune response. Examples of these selective forces on HIV evolution are described. Images Fig. 5 PMID:17060974

  18. Inlet Geomorphology Evolution

    DTIC Science & Technology

    2015-04-01

    APR 2015 2. REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Inlet Geomorphology Evolution 5a. CONTRACT NUMBER 5b...Std Z39-18 Coastal Inlets Research Program Inlet Geomorphology Evolution The Inlet Geomorphology Evolution work unit of the CIRP evaluates

  19. Evolution & Diversity in Plants.

    ERIC Educational Resources Information Center

    Pearson, Lorentz C.

    1988-01-01

    Summarizes recent findings that help in understanding how evolution has brought about the diversity of plant life that presently exists. Discusses basic concepts of evolution, diversity and classification, the three-line hypothesis of plant evolution, the origin of fungi, and the geologic time table. Included are 31 references. (CW)

  20. Arguing for Evolution.

    ERIC Educational Resources Information Center

    Ayala, Francisco J.

    2000-01-01

    Discusses the Kansas State Board of Education's decision to remove references to evolution and cosmology from the state's education standards and assessment. Advocates the need to teach evolution in high schools for a meaningful biology education. Addresses the question whether the teaching of evolution poses a threat to Christianity or other…

  1. Arguing for Evolution.

    ERIC Educational Resources Information Center

    Ayala, Francisco J.

    2000-01-01

    Discusses the Kansas State Board of Education's decision to remove references to evolution and cosmology from the state's education standards and assessment. Advocates the need to teach evolution in high schools for a meaningful biology education. Addresses the question whether the teaching of evolution poses a threat to Christianity or other…

  2. Evolution & Diversity in Plants.

    ERIC Educational Resources Information Center

    Pearson, Lorentz C.

    1988-01-01

    Summarizes recent findings that help in understanding how evolution has brought about the diversity of plant life that presently exists. Discusses basic concepts of evolution, diversity and classification, the three-line hypothesis of plant evolution, the origin of fungi, and the geologic time table. Included are 31 references. (CW)

  3. Frontiers of stellar evolution

    NASA Technical Reports Server (NTRS)

    Lambert, David L. (Editor)

    1991-01-01

    The present conference discusses theoretical and observational views of star formation, spectroscopic constraints on the evolution of massive stars, very low mass stars and brown dwarfs, asteroseismology, globular clusters as tests of stellar evolution, observational tests of stellar evolution, and mass loss from cool evolved giant stars. Also discussed are white dwarfs and hot subdwarfs, neutron stars and black holes, supernovae from single stars, close binaries with evolved components, accretion disks in interacting binaries, supernovae in binary systems, stellar evolution and galactic chemical evolution, and interacting binaries containing compact components.

  4. Evolution prediction from tomography

    NASA Astrophysics Data System (ADS)

    Dominy, Jason M.; Venuti, Lorenzo Campos; Shabani, Alireza; Lidar, Daniel A.

    2017-03-01

    Quantum process tomography provides a means of measuring the evolution operator for a system at a fixed measurement time t. The problem of using that tomographic snapshot to predict the evolution operator at other times is generally ill-posed since there are, in general, infinitely many distinct and compatible solutions. We describe the prediction, in some "maximal ignorance" sense, of the evolution of a quantum system based on knowledge only of the evolution operator for finitely many times 0<τ 1evolution at times away from the measurement times. Even if the original evolution is unitary, the predicted evolution is described by a non-unitary, completely positive map.

  5. Oxygen evolution reaction catalysis

    DOEpatents

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  6. The Evolution of DEOMI

    DTIC Science & Technology

    2017-09-15

    THE EVOLUTION DE MI DEFENSE EQU AL OPPORTU NITY MANAG EMENT INST ITUTE IDENTITY TITLE: Dr. G · NAME: William Ga ry Mc u1re RACE: White NDER...The Evolution of DEOMI Defense Equal Opportunity Management Institute Research Directorate Written by William Gary McGuire, PhD...organization of NTL gives an accurate (although sketchy) picture of the evolution of laboratory practice both in the varying demands of its changing clientele

  7. Speeding up evolution

    NASA Astrophysics Data System (ADS)

    Hoff, Wouter

    Proteins and cells offer great opportunities for green chemistry and renewable energy. However, few of these possible applications have been put into practice because of details that turn out to be major barriers to cost-efficient implementation and that prove difficult to solve by genetic engineering. A better understanding of molecular evolution promises a novel approach to addressing these important challenges. While major advances have been made, major gaps remain in understanding the evolution of proteins. Different approaches to accelerating molecular evolution into targeted directions will be discussed, including recent progress on evolution in non-homogeneous environments.

  8. Evolution: functional evolution of nuclear structure.

    PubMed

    Wilson, Katherine L; Dawson, Scott C

    2011-10-17

    The evolution of the nucleus, the defining feature of eukaryotic cells, was long shrouded in speculation and mystery. There is now strong evidence that nuclear pore complexes (NPCs) and nuclear membranes coevolved with the endomembrane system, and that the last eukaryotic common ancestor (LECA) had fully functional NPCs. Recent studies have identified many components of the nuclear envelope in living Opisthokonts, the eukaryotic supergroup that includes fungi and metazoan animals. These components include diverse chromatin-binding membrane proteins, and membrane proteins with adhesive lumenal domains that may have contributed to the evolution of nuclear membrane architecture. Further discoveries about the nucleoskeleton suggest that the evolution of nuclear structure was tightly coupled to genome partitioning during mitosis.

  9. Utilisation de lignes directrices dans le cadre de l’implantation de cabinets automatisés décentralisés en établissement de santé

    PubMed Central

    Brisseau, Lionel; Bussières, Jean-François; Lebel, Denis; Atkinson, Suzanne; Robinette, Louise; Fortin, Sylvie; Lemay, Michel

    2011-01-01

    RÉSUMÉ Contexte : Il existe peu de données sur les conséquences de l’utilisation des cabinets automatisés décentralisés (CAD) en établissements de santé. Méthode : Il s’agit d’une étude descriptive de la conformité des pratiques par rapport à des lignes directrices publiées dans le cadre de l’implantation de CAD. L’objectif principal de l’étude est d’évaluer la conformité globale et celle de chaque processus du circuit du médicament. L’étude se déroule au sein du Centre hospitalier universitaire (CHU) Sainte-Justine, un établissement mère–enfant de 500 lits. À partir des lignes directrices portant sur l’utilisation sécuritaire des CAD de l’Institute for Safe Medication Practice (aux États-Unis) (2008) et de son outil d’autoévaluation (2009), nous avons évalué la conformité de la pratique à 30 jours et à 120 jours après l’implantation. Résultats : Nous avons procédé de novembre 2009 à avril 2010 à l’implantation de sept stations de CAD au sein du CHU Sainte-Justine. Le profil de conformité est passé de 66 % à 74 % de janvier à avril 2010. Pour chaque processus relatif à l’utilisation sécuritaire des CAD, nous présentons une brève description des critères ainsi que les éléments de non-conformité liés à la technologie ou aux aspects organisationnels. Pour chaque élément de non-conformité, nous avons déterminé les actions requises auprès du fabricant afin de modifier l’équipement (c. à .d. aspects technologiques) et auprès de l’établissement afin de modifier les modalités d’utilisation (aspects organisationnels) en précisant le ou les processus impliqués. Conclusion : Cette étude décrit la conformité des pratiques au CHU Sainte-Justine par rapport à des lignes directrices publiées par l’Institute for Safe Medication Practices. L’utilisation de lignes directrices dans le cadre de l’implantation de cabinets automatisés décentralisés en établissement peut

  10. Surveillance urinaire des professionnels de la santé exposés aux antinéoplasiques dans le cadre de leur travail: revue de la littérature de 2010 à 2015

    PubMed Central

    Poupeau, Céline; Roland, Christel; Bussières, Jean-François

    2016-01-01

    RÉSUMÉ Contexte Il existe de plus en plus de données sur la présence de traces de médicaments dangereux dans l’urine des professionnels de la santé exposés à ces médicaments. Objectif Présenter une revue de la littérature scientifique concernant la surveillance urinaire de professionnels de la santé exposés aux anti-néoplasiques dans le cadre de leur travail. Sources de données Recherche sur PubMed avec les Medical Subject Headings (MeSH) « occupational exposure » et « antineoplastic agents » ainsi que sur Google Scholar avec les termes « antineoplastic », « urine » et « occupational exposure ». Sélection des études et extraction des données L’examen a porté sur tous les articles en anglais et en français ayant trait aux professionnels de la santé exposés à des médicaments dangereux dans le cadre de leur travail, publiés entre le 1er janvier 2010 et le 31 décembre 2015. Les articles ne comportant pas de résultats urinaires et ceux concernant les vétérinaires ainsi que les revues de littérature, les éditoriaux, les lettres à la rédaction et les résumés de congrès ont été exclus. Synthèse des données Vingt-quatre articles ont été retenus. Les études ont été menées dans 52 établissements de santé provenant de sept pays. Elles regroupaient 826 travailleurs exposés à des médicaments dangereux et 175 témoins, notamment des infirmiers (n = 16 études), des pharmaciens (n = 10), des assistants techniques en pharmacie (n = 8), des médecins (n = 7), des aides-soignants (n = 2) et autres (n = 8). Différentes méthodes analytiques ont été utilisées pour quantifier la présence de 13 médicaments dangereux, principalement le cyclophosphamide (n = 16 études), les platines (n = 7) et l’alpha-fluoro-béta-alanine, un métabolite urinaire du 5-fluorouracile (n = 3). La proportion de travailleurs qui ont étés déclarés positifs s’étendait de 0 % (n = 10 études) à 100 % (n = 4). Si l’on ne retient que

  11. Evolution's Erratic Pace

    ERIC Educational Resources Information Center

    Gould, Stephen Jay

    1977-01-01

    Offers an opposing view to Darwin's statement that evolution occurs through gradual change, using fossil species and modes of evolution to lend support to the author's model of "punctuated equilibria," in which... "Lineages change little during most of their history, but events of rapid speciation occasionally punctuate this…

  12. Treatment of Evolution Inconsistent

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2005-01-01

    State standards for academic content vary enormously in how well they cover the topic of evolution, with many of those documents either ignoring or giving scant treatment to the core principles of that established scientific theory. This article presents the analysis of Education Week on state's standards treatment of evolution. Nearly all the…

  13. Self and Evolution.

    ERIC Educational Resources Information Center

    Csikszentmihalyi, Mihaly

    1998-01-01

    Suggests the time has come for humans to direct their own individual evolution and the evolution of the entire species. Argues that ways must be found to encourage individuals, families, and cultures to discover and develop their differentiating characteristics and help these groups integrate with other cultures, customs, and belief systems.…

  14. Treatment of Evolution Inconsistent

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2005-01-01

    State standards for academic content vary enormously in how well they cover the topic of evolution, with many of those documents either ignoring or giving scant treatment to the core principles of that established scientific theory. This article presents the analysis of Education Week on state's standards treatment of evolution. Nearly all the…

  15. Evolution: Theory or Dogma?

    ERIC Educational Resources Information Center

    Mayer, William V.

    In this paper the author examines the question of whether evolution is a theory or a dogma. He refutes the contention that there is a monolithic scientific conspiracy to present evolution as dogma and suggests that his own presentation might be more appropriately entitled "Creationism: Theory or Dogma." (PEB)

  16. Framing Evolution Discussion Intellectually

    ERIC Educational Resources Information Center

    Oliveira, Alandeom W.; Cook, Kristin; Buck, Gayle A.

    2011-01-01

    This study examines how a first-year biology teacher facilitates a series of whole-class discussions about evolution during the implementation of a problem-based unit. A communicative theoretical perspective is adopted wherein evolution discussions are viewed as social events that the teacher can frame intellectually (i.e., present or organize as…

  17. State Standards and Evolution

    ERIC Educational Resources Information Center

    Moore, Randy

    2004-01-01

    Throughout the United States various individuals and groups have tried to subvert science education by removing or weakening the treatment of evolution in state science-education standards. Most states' science-education standards support the teaching of evolution, but many in the general public and some policymakers want science classrooms to…

  18. Evolution of Constructivism

    ERIC Educational Resources Information Center

    Liu, Chu Chih; Chen, I Ju

    2010-01-01

    The contrast between social constructivism and cognitive constructivism are depicted in different ways in many studies. The purpose of this paper is to summarize the evolution of constructivism and put a focus on social constructivism from the perception of Vygotsky. This study provides a general idea of the evolution of constructivism for people…

  19. Evolution & Intelligent Design

    ERIC Educational Resources Information Center

    Staver, John R.

    2003-01-01

    Advocates of Intelligent Design (ID) theory argue that evolution is a theory in crisis, ID is a legitimate scientific theory, and biology teachers should teach the controversy. Supporters of evolutionary theory testify that ID is a religious, not scientific, concept, and evolution is in no danger of bankruptcy, having survived 140 years of…

  20. Framing Evolution Discussion Intellectually

    ERIC Educational Resources Information Center

    Oliveira, Alandeom W.; Cook, Kristin; Buck, Gayle A.

    2011-01-01

    This study examines how a first-year biology teacher facilitates a series of whole-class discussions about evolution during the implementation of a problem-based unit. A communicative theoretical perspective is adopted wherein evolution discussions are viewed as social events that the teacher can frame intellectually (i.e., present or organize as…

  1. Evolution for Young Victorians

    ERIC Educational Resources Information Center

    Lightman, Bernard

    2012-01-01

    Evolution was a difficult topic to tackle when writing books for the young in the wake of the controversies over Darwin's "Origin of Species." Authors who wrote about evolution for the young experimented with different ways of making the complex concepts of evolutionary theory accessible and less controversial. Many authors depicted presented…

  2. Thermodynamical Arguments against Evolution

    ERIC Educational Resources Information Center

    Rosenhouse, Jason

    2017-01-01

    The argument that the second law of thermodynamics contradicts the theory of evolution has recently been revived by anti-evolutionists. In its basic form, the argument asserts that whereas evolution implies that there has been an increase in biological complexity over time, the second law, a fundamental principle of physics, shows this to be…

  3. Hydrogen evolution reaction catalyst

    DOEpatents

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  4. Evolution - A Theory Evolving

    ERIC Educational Resources Information Center

    Weinberg, Janet H.

    1975-01-01

    Presented is an explanation of a non-Darwinian theory of evolution based on the premise that functional differences are the result of many small mutations such as the substitution of one amino acid for another in a large protein molecule. A brief overview of Darwinian evolution and other theories are presented. (EB)

  5. The Nature of Evolution

    ERIC Educational Resources Information Center

    Alles, David L.

    2005-01-01

    The nature of evolution, the historical change in the universe, and the change that is caused by the workings of the dynamic processes at the smallest and largest scales are studied. It is viewed that the cumulative change in the historical systems is caused by evolution, which is a type of causal relationship and evolutionary processes could be…

  6. Reconciling Evolution and Creation.

    ERIC Educational Resources Information Center

    Tax, Sol

    1983-01-01

    Proposes a way to reconcile evolution with creationism by hypothesizing that the universe was created when the scientific evidence shows, speculating that this was when God began the series of creations described in Genesis, and assuming that God gave humans intelligence to uncover the methods by which he ordained scientific evolution. (Author/MJL)

  7. Science, Evolution, and Creationism

    ERIC Educational Resources Information Center

    National Academies Press, 2008

    2008-01-01

    How did life evolve on Earth? The answer to this question can help us understand our past and prepare for our future. Although evolution provides credible and reliable answers, polls show that many people turn away from science, seeking other explanations with which they are more comfortable. In the book "Science, Evolution, and…

  8. Evolution & Intelligent Design

    ERIC Educational Resources Information Center

    Staver, John R.

    2003-01-01

    Advocates of Intelligent Design (ID) theory argue that evolution is a theory in crisis, ID is a legitimate scientific theory, and biology teachers should teach the controversy. Supporters of evolutionary theory testify that ID is a religious, not scientific, concept, and evolution is in no danger of bankruptcy, having survived 140 years of…

  9. State Standards and Evolution

    ERIC Educational Resources Information Center

    Moore, Randy

    2004-01-01

    Throughout the United States various individuals and groups have tried to subvert science education by removing or weakening the treatment of evolution in state science-education standards. Most states' science-education standards support the teaching of evolution, but many in the general public and some policymakers want science classrooms to…

  10. Evolution Under Attack

    ERIC Educational Resources Information Center

    Muench, David; Newell, Norman D.

    1974-01-01

    The article points out the growing attempts by creationists to have special creation presented with evolution in any educational discussion of the origin of life. The evolution theory is shown to be consistent with known scientific facts while the theory of special creation does not adequately account for these facts. (LS)

  11. Reconciling Evolution and Creation.

    ERIC Educational Resources Information Center

    Tax, Sol

    1983-01-01

    Proposes a way to reconcile evolution with creationism by hypothesizing that the universe was created when the scientific evidence shows, speculating that this was when God began the series of creations described in Genesis, and assuming that God gave humans intelligence to uncover the methods by which he ordained scientific evolution. (Author/MJL)

  12. New Insights into Evolution.

    ERIC Educational Resources Information Center

    Stronck, David R.

    1992-01-01

    Presents insights on the controversial issues regarding evolution. This article partitions into the following sections: (1) Mechanisms explaining how evolution happened; (2) Creationist Confusion; (3) Literal Interpretation of the Bible; (4) Public demand for Creationism; (5) No Basis for Debating; and (6) Scientific Creationism is Bible Study.…

  13. EVOLUTION OF INDIVIDUAL CUMULUS,

    DTIC Science & Technology

    In this paper, the evolution of individual cumulus is studied with basic equations involving the drag effect of water droplets and the phase...the thermal conditions and other properties in the evolution process. It is shown that the drag and phase transformation effects on cloud

  14. Science, Evolution, and Creationism

    ERIC Educational Resources Information Center

    National Academies Press, 2008

    2008-01-01

    How did life evolve on Earth? The answer to this question can help us understand our past and prepare for our future. Although evolution provides credible and reliable answers, polls show that many people turn away from science, seeking other explanations with which they are more comfortable. In the book "Science, Evolution, and…

  15. The Nature of Evolution

    ERIC Educational Resources Information Center

    Alles, David L.

    2005-01-01

    The nature of evolution, the historical change in the universe, and the change that is caused by the workings of the dynamic processes at the smallest and largest scales are studied. It is viewed that the cumulative change in the historical systems is caused by evolution, which is a type of causal relationship and evolutionary processes could be…

  16. Evolution's Erratic Pace

    ERIC Educational Resources Information Center

    Gould, Stephen Jay

    1977-01-01

    Offers an opposing view to Darwin's statement that evolution occurs through gradual change, using fossil species and modes of evolution to lend support to the author's model of "punctuated equilibria," in which... "Lineages change little during most of their history, but events of rapid speciation occasionally punctuate this…

  17. Evolution for Young Victorians

    ERIC Educational Resources Information Center

    Lightman, Bernard

    2012-01-01

    Evolution was a difficult topic to tackle when writing books for the young in the wake of the controversies over Darwin's "Origin of Species." Authors who wrote about evolution for the young experimented with different ways of making the complex concepts of evolutionary theory accessible and less controversial. Many authors depicted presented…

  18. Organic chemical evolution

    NASA Technical Reports Server (NTRS)

    Chang, S.

    1981-01-01

    The course of organic chemical evolution preceding the emergence of life on earth is discussed based on evidence of processes occurring in interstellar space, the solar system and the primitive earth. Following a brief review of the equilibrium condensation model for the origin and evolution of the solar system, consideration is given to the nature and organic chemistry of interstellar clouds, comets, Jupiter, meteorites, Venus and Mars, and the prebiotic earth. Major issues to be resolved in the study of organic chemical evolution on earth are identified regarding condensation and accretion in the solar nebula, early geological evolution, the origin and evolution of the atmosphere, organic production rates, organic-inorganic interactions, environmental fluctuations, phase separation and molecular selectivity.

  19. TIDEV: Tidal Evolution package

    NASA Astrophysics Data System (ADS)

    Cuartas-Restrepo, P.; Melita, M.; Zuluaga, J.; Portilla, B.; Sucerquia, M.; Miloni, O.

    2016-09-01

    TIDEV (Tidal Evolution package) calculates the evolution of rotation for tidally interacting bodies using Efroimsky-Makarov-Williams (EMW) formalism. The package integrates tidal evolution equations and computes the rotational and dynamical evolution of a planet under tidal and triaxial torques. TIDEV accounts for the perturbative effects due to the presence of the other planets in the system, especially the secular variations of the eccentricity. Bulk parameters include the mass and radius of the planet (and those of the other planets involved in the integration), the size and mass of the host star, the Maxwell time and Andrade's parameter. TIDEV also calculates the time scale that a planet takes to be tidally locked as well as the periods of rotation reached at the end of the spin-orbit evolution.

  20. How Can Evolution Learn?

    PubMed

    Watson, Richard A; Szathmáry, Eörs

    2016-02-01

    The theory of evolution links random variation and selection to incremental adaptation. In a different intellectual domain, learning theory links incremental adaptation (e.g., from positive and/or negative reinforcement) to intelligent behaviour. Specifically, learning theory explains how incremental adaptation can acquire knowledge from past experience and use it to direct future behaviours toward favourable outcomes. Until recently such cognitive learning seemed irrelevant to the 'uninformed' process of evolution. In our opinion, however, new results formally linking evolutionary processes to the principles of learning might provide solutions to several evolutionary puzzles - the evolution of evolvability, the evolution of ecological organisation, and evolutionary transitions in individuality. If so, the ability for evolution to learn might explain how it produces such apparently intelligent designs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Organic chemical evolution

    NASA Technical Reports Server (NTRS)

    Chang, S.

    1981-01-01

    The course of organic chemical evolution preceding the emergence of life on earth is discussed based on evidence of processes occurring in interstellar space, the solar system and the primitive earth. Following a brief review of the equilibrium condensation model for the origin and evolution of the solar system, consideration is given to the nature and organic chemistry of interstellar clouds, comets, Jupiter, meteorites, Venus and Mars, and the prebiotic earth. Major issues to be resolved in the study of organic chemical evolution on earth are identified regarding condensation and accretion in the solar nebula, early geological evolution, the origin and evolution of the atmosphere, organic production rates, organic-inorganic interactions, environmental fluctuations, phase separation and molecular selectivity.

  2. Cultural Evolution and SETI

    NASA Astrophysics Data System (ADS)

    Dick, S. J.

    2009-12-01

    The Drake Equation for the number of radio communicative technological civilizations in the Galaxy encompasses three components of cosmic evolution: astronomical, biological and cultural. Of these three, cultural evolution totally dominates in terms of the rapidity of its effects. Yet, SETI scientists do not take cultural evolution into account, perhaps for understandable reasons, since cultural evolution is not well-understood even on Earth and is unpredictable in its outcome. But the one certainty for technical civilizations billions, millions, or even thousands of years older than ours is that they will have undergone cultural evolution. Cultural evolution potentially takes place in many directions, but this paper argues that its central driving force is the maintenance, improvement and perpetuation of knowledge and intelligence, and that to the extent intelligence can be improved, it will be improved. Applying this principle to life in the universe, extraterrestrials will have sought the best way to improve their intelligence. One possibility is that they may have long ago advanced beyond flesh-and-blood to artificial intelligence, constituting a postbiological universe. Although this subject has been broached, it has not been given the attention it is due from its foundation in cultural evolution. Nor has the idea of a postbiological universe been carried to its logical conclusion, including a careful analysis of the implications for SETI. SETI scientists, social scientists, and experts in AI should consider the strengths and weaknesses of this new paradigm.

  3. The evolution of airplanes

    NASA Astrophysics Data System (ADS)

    Bejan, A.; Charles, J. D.; Lorente, S.

    2014-07-01

    The prevailing view is that we cannot witness biological evolution because it occurred on a time scale immensely greater than our lifetime. Here, we show that we can witness evolution in our lifetime by watching the evolution of the flying human-and-machine species: the airplane. We document this evolution, and we also predict it based on a physics principle: the constructal law. We show that the airplanes must obey theoretical allometric rules that unite them with the birds and other animals. For example, the larger airplanes are faster, more efficient as vehicles, and have greater range. The engine mass is proportional to the body size: this scaling is analogous to animal design, where the mass of the motive organs (muscle, heart, lung) is proportional to the body size. Large or small, airplanes exhibit a proportionality between wing span and fuselage length, and between fuel load and body size. The animal-design counterparts of these features are evident. The view that emerges is that the evolution phenomenon is broader than biological evolution. The evolution of technology, river basins, and animal design is one phenomenon, and it belongs in physics.

  4. Evolution of thymus organogenesis.

    PubMed

    Ge, Qing; Zhao, Yong

    2013-01-01

    The thymus is the primary organ for functional T lymphocyte development in jawed vertebrates. A new study in the jawless fish, lampreys, indicates the existence of a primitive thymus in these surviving representatives of the most ancient vertebrates, providing strong evidence of co-evolution of T cells and thymus. This review summarizes the wealth of data that have been generated towards understanding the evolution of the thymus in the vertebrates. Progress in identifying genetic networks and cellular mechanisms that control thymus organogenesis in mammals and their evolution in lower species may inspire the development of new strategies for medical interventions targeting faulty thymus functions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Evolution of biological complexity.

    PubMed

    Adami, C; Ofria, C; Collier, T C

    2000-04-25

    To make a case for or against a trend in the evolution of complexity in biological evolution, complexity needs to be both rigorously defined and measurable. A recent information-theoretic (but intuitively evident) definition identifies genomic complexity with the amount of information a sequence stores about its environment. We investigate the evolution of genomic complexity in populations of digital organisms and monitor in detail the evolutionary transitions that increase complexity. We show that, because natural selection forces genomes to behave as a natural "Maxwell Demon," within a fixed environment, genomic complexity is forced to increase.

  6. Evolution of biological complexity

    PubMed Central

    Adami, Christoph; Ofria, Charles; Collier, Travis C.

    2000-01-01

    To make a case for or against a trend in the evolution of complexity in biological evolution, complexity needs to be both rigorously defined and measurable. A recent information-theoretic (but intuitively evident) definition identifies genomic complexity with the amount of information a sequence stores about its environment. We investigate the evolution of genomic complexity in populations of digital organisms and monitor in detail the evolutionary transitions that increase complexity. We show that, because natural selection forces genomes to behave as a natural “Maxwell Demon,” within a fixed environment, genomic complexity is forced to increase. PMID:10781045

  7. Galactic chemical evolution

    NASA Astrophysics Data System (ADS)

    Mollá, M.; Cavichia, O.; da Costa, R.; Gibson, B. K.; Díaz, A. I.

    2017-03-01

    We analyze the evolution of oxygen abundance radial gradients resulting from our chemical evolution models calculated with different prescriptions for the star formation rate (SFR) and for the gas infall rate, in order to assess their respective roles in shaping gradients. We also compare with cosmological simulations and confront all with recent observational datasets, in particular with abundances inferred from planetary nebulae. We demonstrate the critical importance in isolating the specific radial range over which a gradient is measured, in order for their temporal evolution to be useful indicators of disk growth with redshift.

  8. The evolution of vision.

    PubMed

    Gehring, Walter J

    2014-01-01

    In this review, the evolution of vision is retraced from its putative origins in cyanobacteria to humans. Circadian oscillatory clocks, phototropism, and phototaxis require the capability to detect light. Photosensory proteins allow us to reconstruct molecular phylogenetic trees. The evolution of animal eyes leading from an ancestral prototype to highly complex image forming eyes can be deciphered on the basis of evolutionary developmental genetic experiments and comparative genomics. As all bilaterian animals share the same master control gene, Pax6, and the same retinal and pigment cell determination genes, we conclude that the different eye-types originated monophyletically and subsequently diversified by divergent, parallel, or convergent evolution.

  9. Evolution without evolution and without ambiguities

    NASA Astrophysics Data System (ADS)

    Marletto, C.; Vedral, V.

    2017-02-01

    In quantum theory it is possible to explain time, and dynamics, in terms of entanglement. This is the timeless approach to time, which assumes that the universe is in a stationary state, where two noninteracting subsystems, the "clock" and the "rest," are entangled. As a consequence, by choosing a suitable observable of the clock, the relative state of the rest of the universe evolves unitarily with respect to the variable labeling the clock observable's eigenstates, which is then interpreted as time. This model for an "evolution without evolution" (Page and Wootters, 1983), albeit elegant, has never been developed further, because it was criticized for generating severe ambiguities in the dynamics of the rest of the universe. In this paper we show that there are no such ambiguities; we also update the model, making it amenable to possible new applications.

  10. Heredity in Evolution & Evolution of Heredity

    NASA Astrophysics Data System (ADS)

    Rivoire, Olivier

    2015-03-01

    The inheritance of characteristics induced by the environment has often been opposed to the theory of evolution by natural selection. However, although evolution by natural selection requires new heritable traits to be produced and transmitted, it does not prescribe, per se, the mechanisms by which this is operated. The mechanisms of inheritance are not, however, unconstrained, because they are themselves subject to natural selection. We introduce a schematic, analytically solvable mathematical model to compare the adaptive value of different schemes of inheritance. Our model allows for variations to be inherited, randomly produced, or environmentally induced, and, irrespectively, to be either transmitted or not during reproduction. The adaptation of the different schemes for processing variations is quantified for a range of fluctuating environments, following an approach that links quantitative genetics with stochastic control theory.

  11. Evolution of models for evolution. [of life

    NASA Technical Reports Server (NTRS)

    Rohlfing, D. L.

    1974-01-01

    The paper discusses models of evolution and their values, and some critiques of these models and the value of these critiques. A model is investigated which involves the formation of prebiotic protein from amino acids. Its formation by four theoretical critiques that suggest alternative environmental conditions is discussed. Experiments are reviewed so as to illustrate the experimental testing of the possible weaknesses of a model for a single molecular evolutionary phase and to suggest some necessary changes in the model.

  12. Evolution of models for evolution. [of life

    NASA Technical Reports Server (NTRS)

    Rohlfing, D. L.

    1974-01-01

    The paper discusses models of evolution and their values, and some critiques of these models and the value of these critiques. A model is investigated which involves the formation of prebiotic protein from amino acids. Its formation by four theoretical critiques that suggest alternative environmental conditions is discussed. Experiments are reviewed so as to illustrate the experimental testing of the possible weaknesses of a model for a single molecular evolutionary phase and to suggest some necessary changes in the model.

  13. Co-Evolution.

    ERIC Educational Resources Information Center

    McGhee, Robert

    2002-01-01

    Discusses the role of techniques of DNA analysis in assessing the genetic relationships between various species. Focuses on wolf-dog evolution using DNA evidence and historical data about human/wolf-dog relationships. (DDR)

  14. Stochasticity in evolution.

    PubMed

    Lenormand, Thomas; Roze, Denis; Rousset, François

    2009-03-01

    The debate over the role of stochasticity is central in evolutionary biology, often summarised by whether or not evolution is predictable or repeatable. Here we distinguish three types of stochasticity: stochasticity of mutation and variation, of individual life histories and of environmental change. We then explain when stochasticity matters in evolution, distinguishing four broad situations: stochasticity contributes to maladaptation or limits adaptation; it drives evolution on flat fitness landscapes (evolutionary freedom); it might promote jumps from one fitness peak to another (evolutionary revolutions); and it might shape the selection pressures themselves. We show that stochasticity, by directly steering evolution, has become an essential ingredient of evolutionary theory beyond the classical Wright-Fisher or neutralist-selectionist debates.

  15. Experimental evolution gone wild.

    PubMed

    Scheinin, M; Riebesell, U; Rynearson, T A; Lohbeck, K T; Collins, S

    2015-05-06

    Because of their large population sizes and rapid cell division rates, marine microbes have, or can generate, ample variation to fuel evolution over a few weeks or months, and subsequently have the potential to evolve in response to global change. Here we measure evolution in the marine diatom Skeletonema marinoi evolved in a natural plankton community in CO2-enriched mesocosms deployed in situ. Mesocosm enclosures are typically used to study how the species composition and biogeochemistry of marine communities respond to environmental shifts, but have not been used for experimental evolution to date. Using this approach, we detect a large evolutionary response to CO2 enrichment in a focal marine diatom, where population growth rate increased by 1.3-fold in high CO2-evolved lineages. This study opens an exciting new possibility of carrying out in situ evolution experiments to understand how marine microbial communities evolve in response to environmental change.

  16. The evolution of galaxies

    NASA Technical Reports Server (NTRS)

    Gunn, J. E.

    1982-01-01

    The recent observational evidence on the evolution of galaxies is reviewed and related to the framework of current ideas for galaxy formation from primordial density fluctuations. Recent strong evidence for the evolution of the stellar population in ellipticals is presented, as well as evidence that not all ellipticals behave as predicted by any simple theory. The status of counts of faint galaxies and the implications for the evolution of spirals is discussed, together with a discussion of recent work on the redshift distribution of galaxies at faint magnitudes and a spectroscopic investigation of the Butcher-Oemler blue cluster galaxies. Finally a new picture for the formation and evolution of disk galaxies which may explain most of the features of the Hubble sequence is outlined.

  17. Co-Evolution.

    ERIC Educational Resources Information Center

    McGhee, Robert

    2002-01-01

    Discusses the role of techniques of DNA analysis in assessing the genetic relationships between various species. Focuses on wolf-dog evolution using DNA evidence and historical data about human/wolf-dog relationships. (DDR)

  18. Evolution of oncolytic viruses.

    PubMed

    Sanjuán, Rafael; Grdzelishvili, Valery Z

    2015-08-01

    Owing to their replicative capacity, oncolytic viruses (OVs) can evolve under the action of natural selection. Reversion to virulence and recombination with wild-type strains may compromise OV safety, therefore requiring evolutionary risk assessment studies. On the other hand, evolution can be directed in the laboratory to create more potent and safer OVs. Previous work in the experimental evolution field provides a background for OV directed evolution, and has identified interesting exploitable features. While genetic engineering has greatly advanced the field of oncolytic virotherapy, this approach is sometimes curtailed by the complexity and diversity of virus-host interactions. Directed evolution provides an alternative approach that may help to obtain new OVs without prejudice toward the underlying molecular mechanisms involved. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Evolution: Always New

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    2005-01-01

    The changes in the evolution due to changes in science are explored. These changes are frustrating to paleontologists, especially when they are trying to date a singular event, like a cataclysm that precipitated a mass extinction.

  20. Experimental evolution gone wild

    PubMed Central

    Scheinin, M.; Riebesell, U.; Rynearson, T. A.; Lohbeck, K. T.; Collins, S.

    2015-01-01

    Because of their large population sizes and rapid cell division rates, marine microbes have, or can generate, ample variation to fuel evolution over a few weeks or months, and subsequently have the potential to evolve in response to global change. Here we measure evolution in the marine diatom Skeletonema marinoi evolved in a natural plankton community in CO2-enriched mesocosms deployed in situ. Mesocosm enclosures are typically used to study how the species composition and biogeochemistry of marine communities respond to environmental shifts, but have not been used for experimental evolution to date. Using this approach, we detect a large evolutionary response to CO2 enrichment in a focal marine diatom, where population growth rate increased by 1.3-fold in high CO2-evolved lineages. This study opens an exciting new possibility of carrying out in situ evolution experiments to understand how marine microbial communities evolve in response to environmental change. PMID:25833241

  1. Evolution, epigenetics and cooperation.

    PubMed

    Bateson, Patrick

    2014-04-01

    Explanations for biological evolution in terms of changes in gene frequencies refer to outcomes rather than process. Integrating epigenetic studies with older evolutionary theories has drawn attention to the ways in which evolution occurs. Adaptation at the level of the gene is givingway to adaptation at the level of the organism and higher-order assemblages of organisms. These ideas impact on the theories of how cooperation might have evolved. Two of the theories, i.e. that cooperating individuals are genetically related or that they cooperate for self-interested reasons, have been accepted for a long time. The idea that adaptation takes place at the level of groups is much more controversial. However, bringing together studies of development with those of evolution is taking away much of the heat in the debate about the evolution of group behaviour.

  2. Stellar evolution. VI.

    NASA Technical Reports Server (NTRS)

    Iben, I., Jr.

    1967-01-01

    Evolution of low mass Population I stars from main sequence to red giant branch in Hertzsprung- Russell diagram, through energy generation phases of p-p chain reactions /dominating over C-N cycle reactions/ and hydrogen burning

  3. Baculovirus phylogeny and evolution.

    PubMed

    Herniou, Elisabeth A; Jehle, Johannes A

    2007-10-01

    The family Baculoviridae represents one of the largest and most diverse groups of viruses and a unique model for studying the forces driving the evolution and biodiversity of double-stranded DNA viruses with large genomes. With the advent of comparative genomics, the phylogenetic relationships of baculoviruses have been put on solid bases. This, as well as improved bioinformatic approaches, has provided a detailed picture of baculovirus phylogeny and evolution. According to the present knowledge, baculoviruses can be classified into at least four evolutionary lineages: the most ancestral dipteran nucleopolyhedroviruses, the hymenopteran nucleopolyhedroviruses and the lepidopteran nucleopolyhedroviruses and granuloviruses. Despite the growing understanding of baculovirus phylogeny and macro-evolution, our knowledge of the micro-evolutionary processes within baculovirus species and virus populations is still limited. Here we present the state of the art on baculovirus phylogeny and evolution.

  4. Grand Views of Evolution.

    PubMed

    de Vladar, Harold P; Santos, Mauro; Szathmáry, Eörs

    2017-05-01

    Despite major advances in evolutionary theories, some aspects of evolution remain neglected: whether evolution: would come to a halt without abiotic change; is unbounded and open-ended; or is progressive and something beyond fitness is maximized. Here, we discuss some models of ecology and evolution and argue that ecological change, resulting in Red Queen dynamics, facilitates (but does not ensure) innovation. We distinguish three forms of open-endedness. In weak open-endedness, novel phenotypes can occur indefinitely. Strong open-endedness requires the continual appearance of evolutionary novelties and/or innovations. Ultimate open-endedness entails an indefinite increase in complexity, which requires unlimited heredity. Open-ended innovation needs exaptations that generate novel niches. This can result in new traits and new rules as the dynamics unfolds, suggesting that evolution is not fully algorithmic. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Physical Principles of Evolution

    NASA Astrophysics Data System (ADS)

    Schuster, Peter

    Theoretical biology is incomplete without a comprehensive theory of evolution, since evolution is at the core of biological thought. Evolution is visualized as a migration process in genotype or sequence space that is either an adaptive walk driven by some fitness gradient or a random walk in the absence of (sufficiently large) fitness differences. The Darwinian concept of natural selection consisting in the interplay of variation and selection is based on a dichotomy: All variations occur on genotypes whereas selection operates on phenotypes, and relations between genotypes and phenotypes, as encapsulated in a mapping from genotype space into phenotype space, are central to an understanding of evolution. Fitness is conceived as a function of the phenotype, represented by a second mapping from phenotype space into nonnegative real numbers. In the biology of organisms, genotype-phenotype maps are enormously complex and relevant information on them is exceedingly scarce. The situation is better in the case of viruses but so far only one example of a genotype-phenotype map, the mapping of RNA sequences into RNA secondary structures, has been investigated in sufficient detail. It provides direct information on RNA selection in vitro and test-tube evolution, and it is a basis for testing in silico evolution on a realistic fitness landscape. Most of the modeling efforts in theoretical and mathematical biology today are done by means of differential equations but stochastic effects are of undeniably great importance for evolution. Population sizes are much smaller than the numbers of genotypes constituting sequence space. Every mutant, after all, has to begin with a single copy. Evolution can be modeled by a chemical master equation, which (in principle) can be approximated by a stochastic differential equation. In addition, simulation tools are available that compute trajectories for master equations. The accessible population sizes in the range of 10^7le Nle 10

  6. Manipulation of quantum evolution

    NASA Technical Reports Server (NTRS)

    Cabera, David Jose Fernandez; Mielnik, Bogdan

    1994-01-01

    The free evolution of a non-relativistic charged particle is manipulated using time-dependent magnetic fields. It is shown that the application of a programmed sequence of magnetic pulses can invert the free evolution process, forcing an arbitrary wave packet to 'go back in time' to recover its past shape. The possibility of more general operations upon the Schrodinger wave packet is discussed.

  7. Population genetics and evolution

    SciTech Connect

    De Jong, G.

    1988-01-01

    This volume reevaluates the position of population genetics in evolutionary biology by using population genetics as the tool to study the role of development and adaptation in evolution. The emphasis is on the organismic process of selection, and on how the study of selection means connecting variation at the molecular, biochemical, and phenotypic levels of organization with the resulting variation in fitness. This book illustrates that the tendency to view single locus differences in isolation as the building blocks of evolution is disappearing.

  8. Topology of viral evolution.

    PubMed

    Chan, Joseph Minhow; Carlsson, Gunnar; Rabadan, Raul

    2013-11-12

    The tree structure is currently the accepted paradigm to represent evolutionary relationships between organisms, species or other taxa. However, horizontal, or reticulate, genomic exchanges are pervasive in nature and confound characterization of phylogenetic trees. Drawing from algebraic topology, we present a unique evolutionary framework that comprehensively captures both clonal and reticulate evolution. We show that whereas clonal evolution can be summarized as a tree, reticulate evolution exhibits nontrivial topology of dimension greater than zero. Our method effectively characterizes clonal evolution, reassortment, and recombination in RNA viruses. Beyond detecting reticulate evolution, we succinctly recapitulate the history of complex genetic exchanges involving more than two parental strains, such as the triple reassortment of H7N9 avian influenza and the formation of circulating HIV-1 recombinants. In addition, we identify recurrent, large-scale patterns of reticulate evolution, including frequent PB2-PB1-PA-NP cosegregation during avian influenza reassortment. Finally, we bound the rate of reticulate events (i.e., 20 reassortments per year in avian influenza). Our method provides an evolutionary perspective that not only captures reticulate events precluding phylogeny, but also indicates the evolutionary scales where phylogenetic inference could be accurate.

  9. Proceedings. Pharmacy Cadre Training Structured Externship Program.

    ERIC Educational Resources Information Center

    Kansas Univ., Lawrence. School of Pharmacy.

    The proceedings are for two workshops, held in November 1972 and April 1973, in the process of establishing a structured externship in pharmacy. At the first workshop the field instructors were apprised of the goals and techniques of the project, and the policy of the program was developed. At the followup workshop the experiences of the first…

  10. Critical Review of the Navy Space Cadre

    DTIC Science & Technology

    2014-06-01

    officer IGY international geophysical year IP Information Professional Community ISR intelligence, surveillance, and reconnaissance IW Information...Warfare Command, 2013), 8. 10 Ibid. 3 Meteorology/Oceanography (METOC), Information Warfare (IW), Information Professional ( IP ), Intelligence, and...Space Surveillance System (Space Fence) from 1958 to 1961. The Space Fence included three transmitter and six receiver stations along the 33.5-degree

  11. Energy and Evolution

    NASA Astrophysics Data System (ADS)

    Porter, George

    I have called my lecture Energy and Evolution, and that embraces Physics and Biology. I suppose that what I have in mind are the great things that have happened in the last 135 years since Charles Darwin; and the great problems that we have in this field today. In 1859 Charles Darwin wrote history on a grand scale and he gave mankind an intellectual shock which changed our concept of ourselves and our place in the world. Rather suddenly we have come to realize that the process of natural evolution which he described and which has served the world for three billion years may be about to cease or least to change in a profound way. The Darwinian changes of evolution occurred slowly, unnoticed by participants who had very little to say about the forms that their descendants would take. They merely flocked to survive and if they survived they had one privilege only and that was the privilege of handing on their genes. The situation has changed drastically in the last few years. One species, man now so dominates the earth that it is in his part to eliminate most of the other species if he so wishes. Those who do survive do so only because man finds them interesting and useful and he is busy with the natural evolution even of these. It is the end of the evolution, as Darwin knew it. Far greater powers to play God will soon be in our hands. Genetic Engineering will enable us to eliminate conquered genes and other unfavorable genetic information and even to change the nature of mankind. We may not wish to do this but it will become possible. What we see happening is a rapid transfer of responsibility for the future evolution into the hands of ourselves, the hands of one species, homosapiens. We are no longer pawns in the game of evolution. We are not even the kings and queens, we are the players.

  12. Creationism, Evolution, and Science Education

    SciTech Connect

    Scott, Eugenie C.

    2005-06-22

    Many topics in the curriculum of American schools are controversial, but perhaps the one with the longest tenure is evolution. Three arguments are made against evolution: that it is allegedly weak science ('evolution is a theory in crisis'); that it is incompatible with religion; and that it is only 'fair' to 'balance' evolution with creationism. Regardless of the appropriateness of their application to science education, all three of the arguments are made to try to restrict the teaching of evolution. Variants of the fairness argument such as balancing evolution with 'scientific alternatives to evolution' or balancing evolution with 'arguments against evolution' have in fact become the current predominant antievolutionist strategy. Current events in the creationism/evolution controversy will be reviewed, and suggestions made for how to promote sound science education in the schools.

  13. The evolution of language

    PubMed Central

    Nowak, Martin A.; Krakauer, David C.

    1999-01-01

    The emergence of language was a defining moment in the evolution of modern humans. It was an innovation that changed radically the character of human society. Here, we provide an approach to language evolution based on evolutionary game theory. We explore the ways in which protolanguages can evolve in a nonlinguistic society and how specific signals can become associated with specific objects. We assume that early in the evolution of language, errors in signaling and perception would be common. We model the probability of misunderstanding a signal and show that this limits the number of objects that can be described by a protolanguage. This “error limit” is not overcome by employing more sounds but by combining a small set of more easily distinguishable sounds into words. The process of “word formation” enables a language to encode an essentially unlimited number of objects. Next, we analyze how words can be combined into sentences and specify the conditions for the evolution of very simple grammatical rules. We argue that grammar originated as a simplified rule system that evolved by natural selection to reduce mistakes in communication. Our theory provides a systematic approach for thinking about the origin and evolution of human language. PMID:10393942

  14. The Evolution of Language

    NASA Astrophysics Data System (ADS)

    Nowak, Martin A.; Krakauer, David C.

    1999-07-01

    The emergence of language was a defining moment in the evolution of modern humans. It was an innovation that changed radically the character of human society. Here, we provide an approach to language evolution based on evolutionary game theory. We explore the ways in which protolanguages can evolve in a nonlinguistic society and how specific signals can become associated with specific objects. We assume that early in the evolution of language, errors in signaling and perception would be common. We model the probability of misunderstanding a signal and show that this limits the number of objects that can be described by a protolanguage. This "error limit" is not overcome by employing more sounds but by combining a small set of more easily distinguishable sounds into words. The process of "word formation" enables a language to encode an essentially unlimited number of objects. Next, we analyze how words can be combined into sentences and specify the conditions for the evolution of very simple grammatical rules. We argue that grammar originated as a simplified rule system that evolved by natural selection to reduce mistakes in communication. Our theory provides a systematic approach for thinking about the origin and evolution of human language.

  15. Workshop on Molecular Evolution

    NASA Technical Reports Server (NTRS)

    Cummings, Michael P.

    2004-01-01

    Molecular evolution has become the nexus of many areas of biological research. It both brings together and enriches such areas as biochemistry, molecular biology, microbiology, population genetics, systematics, developmental biology, genomics, bioinformatics, in vitro evolution, and molecular ecology. The Workshop provides an important contribution to these fields in that it promotes interdisciplinary research and interaction, and thus provides a glue that sticks together disparate fields. Due to the wide range of fields addressed by the study of molecular evolution, it is difficult to offer a comprehensive course in a university setting. It is rare for a single institution to maintain expertise in all necessary areas. In contrast, the Workshop is uniquely able to provide necessary breadth and depth by utilizing a large number of faculty with appropriate expertise. Furthermore, the flexible nature of the Workshop allows for rapid adaptation to changes in the dynamic field of molecular evolution. For example, the 2003 Workshop included recently emergent research areas of molecular evolution of development and genomics.

  16. Evolution and Christian Faith

    NASA Astrophysics Data System (ADS)

    Roughgarden, J. E.

    2006-12-01

    My recent book, Evolution and Christian Faith explores how evolutionary biology can be portrayed from the religious perspective of Christianity. The principal metaphors for evolutionary biology---differential success at breeding and random mutation, probably originate with the dawn of agriculture and clearly occur in the Bible. The central narrative of evolutionary biology can be presented using Biblical passages, providing an account of evolution that is inherently friendly to a Christian perspective. Still, evolutionary biology is far from complete, and problematic areas pertain to species in which the concept of an individual is poorly defined, and to species in which the expression of gender and sexuality depart from Darwin's sexual-selection templates. The present- day controversy in the US about teaching evolution in the schools provides an opportunity to engage the public about science education.

  17. B-chromosome evolution.

    PubMed Central

    Camacho, J P; Sharbel, T F; Beukeboom, L W

    2000-01-01

    B chromosomes are extra chromosomes to the standard complement that occur in many organisms. They can originate in a number of ways including derivation from autosomes and sex chromosomes in intra- and interspecies crosses. Their subsequent molecular evolution resembles that of univalent sex chromosomes, which involves gene silencing, heterochromatinization and the accumulation of repetitive DNA and transposons. B-chromosome frequencies in populations result from a balance between their transmission rates and their effects on host fitness. Their long-term evolution is considered to be the outcome of selection on the host genome to eliminate B chromosomes or suppress their effects and on the B chromosome's ability to escape through the generation of new variants. Because B chromosomes interact with the standard chromosomes, they can play an important role in genome evolution and may be useful for studying molecular evolutionary processes. PMID:10724453

  18. Experimental evolution of multicellularity

    PubMed Central

    Ratcliff, William C.; Denison, R. Ford; Borrello, Mark; Travisano, Michael

    2012-01-01

    Multicellularity was one of the most significant innovations in the history of life, but its initial evolution remains poorly understood. Using experimental evolution, we show that key steps in this transition could have occurred quickly. We subjected the unicellular yeast Saccharomyces cerevisiae to an environment in which we expected multicellularity to be adaptive. We observed the rapid evolution of clustering genotypes that display a novel multicellular life history characterized by reproduction via multicellular propagules, a juvenile phase, and determinate growth. The multicellular clusters are uniclonal, minimizing within-cluster genetic conflicts of interest. Simple among-cell division of labor rapidly evolved. Early multicellular strains were composed of physiologically similar cells, but these subsequently evolved higher rates of programmed cell death (apoptosis), an adaptation that increases propagule production. These results show that key aspects of multicellular complexity, a subject of central importance to biology, can readily evolve from unicellular eukaryotes. PMID:22307617

  19. Dust evolution from comets

    NASA Technical Reports Server (NTRS)

    Sekanina, Z.

    1977-01-01

    The studies of the evolution of cometary debris are reviewed. The subject is divided into three major sections: (1) the developments in the immediate vicinity of the cometary nucleus, which is the source of the dust; (2) the formation of the dust tail; and (3) the blending of the debris with the dust component of interplanetary matter. The importance of the physical theory of comets is emphasized for the understanding of the early phase of the evolution of cometary dust. A physico-dynamical model designed to analyze the particle-emission mechanism from the distribution of light in the dust tails is described and the results are presented. Increased attention is paid to large particles because of their importance for the evolution of the zodiacal cloud. Finally, implications are discussed for the future in situ investigations of comets.

  20. Dust evolution from comets

    NASA Technical Reports Server (NTRS)

    Sekanina, Z.

    1976-01-01

    The studies of the evolution of cometary debris are reviewed. The subject is divided into three major sections: (1) the developments in the immediate vicinity of the cometary nucleus, which is the source of the dust; (2) the formation of the dust tail; and (3) the blending of the debris with the dust component of interplanetary matter. The importance of the physical theory of comets is emphasized for the understanding of the early phase of evolution. A physico-dynamical model designed to analyze the particle-emission mechanism from the distribution of light in the dust tail is described and the results are presented. Increased attention is paid to large particles because of their importance for the evolution of the zodiacal cloud. Finally, implications are discussed for the future in situ investigations of comets.

  1. Ethics, evolution and culture.

    PubMed

    Mesoudi, Alex; Danielson, Peter

    2008-08-01

    Recent work in the fields of evolutionary ethics and moral psychology appears to be converging on a single empirically- and evolutionary-based science of morality or ethics. To date, however, these fields have failed to provide an adequate conceptualisation of how culture affects the content and distribution of moral norms. This is particularly important for a large class of moral norms relating to rapidly changing technological or social environments, such as norms regarding the acceptability of genetically modified organisms. Here we suggest that a science of morality/ethics can benefit from adopting a cultural evolution or gene-culture coevolution approach, which treats culture as a second, separate evolutionary system that acts in parallel to biological/genetic evolution. This cultural evolution approach brings with it a set of established theoretical concepts (e.g. different cultural transmission mechanisms) and empirical methods (e.g. evolutionary game theory) that can significantly improve our understanding of human morality.

  2. Characterizing gene family evolution

    PubMed Central

    Liberles, David A.

    2008-01-01

    Gene families are widely used in comparative genomics, molecular evolution, and in systematics. However, they are constructed in different manners, their data analyzed and interpreted differently, with different underlying assumptions, leading to sometimes divergent conclusions. In systematics, concepts like monophyly and the dichotomy between homoplasy and homology have been central to the analysis of phylogenies. We critique the traditional use of such concepts as applied to gene families and give examples of incorrect inferences they may lead to. Operational definitions that have emerged within functional genomics are contrasted with the common formal definitions derived from systematics. Lastly, we question the utility of layers of homology and the meaning of homology at the character state level in the context of sequence evolution. From this, we move forward to present an idealized strategy for characterizing gene family evolution for both systematic and functional purposes, including recent methodological improvements. PMID:19461954

  3. QCD Evolution 2016

    NASA Astrophysics Data System (ADS)

    The QCD Evolution 2016 workshop was held at the National Institute for Subatomic Physics (Nikhef) in Amsterdam, May 30 - June 3, 2016. The workshop is a continuation of a series of workshops held during five consecutive years, in 2011, 2012, 2013, 2015 at Jefferson Lab, and in 2014 in Santa Fe, NM. With the rapid developments in our understanding of the evolution of parton distributions including low-x, TMDs, GPDs, higher-twist correlation functions, and the associated progress in perturbative QCD, lattice QCD and effective field theory techniques, we look forward to yet another exciting meeting in 2016. The program of QCD Evolution 2016 will pay special attention to the topics of importance for ongoing experiments, in the full range from Jefferson Lab energies to LHC energies or future experiments such as a future Electron Ion Collider, recently recommended as a highest priority in U.S. Department of Energy's 2015 Long Range Plan for Nuclear Science.

  4. Computational evolution: taking liberties.

    PubMed

    Correia, Luís

    2010-09-01

    Evolution has, for a long time, inspired computer scientists to produce computer models mimicking its behavior. Evolutionary algorithm (EA) is one of the areas where this approach has flourished. EAs have been used to model and study evolution, but they have been especially developed for their aptitude as optimization tools for engineering. Developed models are quite simple in comparison with their natural sources of inspiration. However, since EAs run on computers, we have the freedom, especially in optimization models, to test approaches both realistic and outright speculative, from the biological point of view. In this article, we discuss different common evolutionary algorithm models, and then present some alternatives of interest. These include biologically inspired models, such as co-evolution and, in particular, symbiogenetics and outright artificial operators and representations. In each case, the advantages of the modifications to the standard model are identified. The other area of computational evolution, which has allowed us to study basic principles of evolution and ecology dynamics, is the development of artificial life platforms for open-ended evolution of artificial organisms. With these platforms, biologists can test theories by directly manipulating individuals and operators, observing the resulting effects in a realistic way. An overview of the most prominent of such environments is also presented. If instead of artificial platforms we use the real world for evolving artificial life, then we are dealing with evolutionary robotics (ERs). A brief description of this area is presented, analyzing its relations to biology. Finally, we present the conclusions and identify future research avenues in the frontier of computation and biology. Hopefully, this will help to draw the attention of more biologists and computer scientists to the benefits of such interdisciplinary research.

  5. Some thoughts on evolution.

    PubMed

    Conyers, R A; Fazzalari, N L

    1980-01-01

    The sparsity of transitional forms and the abrupt appearance of higher taxa in the fossil record are enigmas for the neo-Darwinian theory of evolution. If the cell is considered to be a steady state system then mutations affecting non-regulatory proteins will have far less effect on the steady state than mutations affecting regulatory proteins. This latter type of mutation, when expressed in multicellular biological systems, is a sufficient explanation for the discontinuities observed between species. Such a mechanism, however, has its own implications for any theory of evolution.

  6. On quasar evolution.

    NASA Technical Reports Server (NTRS)

    Cavaliere, A.; Morrison, P.; Wood, K.

    1971-01-01

    We examine the consequences for quasar statistics of a class of models describing the evolution of individual strong sources. The continuity equation for the change of density and luminosity with cosmological epoch determines the population, once a model for the evolution of an individual object is chosen. A dynamical model of spinning objects seems to agree satisfactorily with the present observational sample, both in density and in luminosity function; such a model requires that an individual object strongly brightens as time goes on. A genetic relationship between quasars and radio galaxies which qualitatively fits the observations is suggested by the model.

  7. Macrothermodynamics of Biological Evolution:

    NASA Astrophysics Data System (ADS)

    Gladyshev, Georgi P.

    The author sets forth general considerations pertaining to the thermodynamic theory of biological evolution and the aging of living organisms. It becomes much easier to comprehend the phenomenon of life scrutinizing the formation of structural hierarchies of biological matter applying different temporal scales. These scales are 'identified' by nature itself, and this is reflected in the law of temporal hierarchies. The author discusses some misunderstandings in thermodynamics and evolutionary biology. A simple physicochemical model of biological evolution and the development of living beings is proposed. The considered theory makes it possible to use physicochemical evaluations to develop effective anti-aging diets.

  8. Calibrating bacterial evolution

    PubMed Central

    Ochman, Howard; Elwyn, Susannah; Moran, Nancy A.

    1999-01-01

    Attempts to calibrate bacterial evolution have relied on the assumption that rates of molecular sequence divergence in bacteria are similar to those of higher eukaryotes, or to those of the few bacterial taxa for which ancestors can be reliably dated from ecological or geological evidence. Despite similarities in the substitution rates estimated for some lineages, comparisons of the relative rates of evolution at different classes of nucleotide sites indicate no basis for their universal application to all bacteria. However, there is evidence that bacteria have a constant genome-wide mutation rate on an evolutionary time scale but that this rate differs dramatically from the rate estimated by experimental methods. PMID:10535975

  9. [Biological evolution and specialization].

    PubMed

    Luo, Weizhen; Wang, Deli

    2003-12-01

    There were some disputes about the concept and mechanism of biological evolution. This paper tried to give more explanations on the key concepts. The biological adaptability was distinguished into two different concepts: biological evolution and specialization. The former was defined as the process of biologically gradual evolvement, and the latter was considered as the process of species formation at horizontal development. Moreover, a new conceptual framework was applied to the popular biological theories known by people, and the previous research results or discoveries were explained over again.

  10. Evolution and social epidemiology.

    PubMed

    Nishi, Akihiro

    2015-11-01

    Evolutionary biology, which aims to explain the dynamic process of shaping the diversity of life, has not yet significantly affected thinking in social epidemiology. Current challenges in social epidemiology include understanding how social exposures can affect our biology, explaining the dynamics of society and health, and designing better interventions that are mindful of the impact of exposures during critical periods. I review how evolutionary concepts and tools, such as fitness gradient in cultural evolution, evolutionary game theory, and contemporary evolution in cancer, can provide helpful insights regarding social epidemiology. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Evolution of proteins.

    NASA Technical Reports Server (NTRS)

    Dayhoff, M. O.

    1971-01-01

    The amino acid sequences of proteins from living organisms are dealt with. The structure of proteins is first discussed; the variation in this structure from one biological group to another is illustrated by the first halves of the sequences of cytochrome c, and a phylogenetic tree is derived from the cytochrome c data. The relative geological times associated with the events of this tree are discussed. Errors which occur in the duplication of cells during the evolutionary process are examined. Particular attention is given to evolution of mutant proteins, globins, ferredoxin, and transfer ribonucleic acids (tRNA's). Finally, a general outline of biological evolution is presented.

  12. Software evolution. What kind of evolution?

    NASA Astrophysics Data System (ADS)

    Torres-Carbonell, J. J.; Parets-Llorca, J.

    2001-06-01

    Most Software Systems capable of adapting to the environment or of performing some kind of adaptive activity (such as pattern learning, behavior simulations and the like) use concepts and models from Biology. Nevertheless, such approaches are based on the Modern Synthesis, i.e., Darwinism plus Mendelism, and this implies preadaptive mutations in, and subsequent selection of the better adapted individuals. These pre-adaptive changes usually do not produce the desired effect, are virtually useless and require some kind of backtracking for the system to obtain profit from adaptation. It is our contention that an evolutionary approach in Software Systems development cannot be based on pre-adaptive mutations, but rather on post-adaptive ones, that is, anticipatory mutations and modifications (Lamarkism). A novel way of understanding evolution in Software Systems based on applied Lamarkism is presented and a framework that allows the incorporation of modifications according to the necessities of the system and the will of the modeller is proposed.

  13. The Evolution of Empathy

    ERIC Educational Resources Information Center

    Hackney, Harold

    1978-01-01

    Therapeutic empathy has been an often-used construct by counseling professionals. Through that usage, the term has evolved in meaning and significance from its original presentation by Carl Rogers. This article traces that evolution by identifying its users and contributors over the past 20 years. (Author)

  14. Technologies for ECLSS Evolution

    NASA Technical Reports Server (NTRS)

    Diamant, Bryce L.

    1990-01-01

    Viewgraphs and discussion on technologies for Environmental Control and Life Support System (ECLSS) evolution are presented. Topics covered include: atmosphere revitalization including CO2 removal, CO2 reduction, O2 generation, and trace contaminant control; water recovery and management including urine processing, hygiene water processing, and potable water processing; and waste management. ECLSS technology schematics, process diagrams, and fluid interfaces are included.

  15. The Evolution of Darwinism.

    ERIC Educational Resources Information Center

    Stebbins, G. Ledyard; Ayala, Francisco J.

    1985-01-01

    Recent developments in molecular biology and new interpretations of the fossil record are gradually altering and adding to Charles Darwin's theory, which has been the standard view of the process of evolution for 40 years. Several of these developments and interpretations are identified and discussed. (JN)

  16. Darwinism: Evolution or Revolution?

    ERIC Educational Resources Information Center

    Holt, Niles R.

    1989-01-01

    Maintains that Darwin's theory of evolution was more than a science versus religion debate; rather it was a revolutionary concept that influenced numerous social and political ideologies and movements throughout western history. Traces the impact of Darwin's work historically, utilizing a holistic approach. (RW)

  17. Tectonic Evolution of Mars

    NASA Technical Reports Server (NTRS)

    Phillips, Roger J.

    1992-01-01

    The Final Technical Report on tectonic evolution of Mars is presented. Two papers and an abstract are included. Topics addressed include: scientific rationale and requirements for a global seismic network on Mars, permanent uplift in magmatic systems with application to the Tharsis Region of Mars, and the geophysical signal of the Martian global dichotomy.

  18. Darwinism: Evolution or Revolution?

    ERIC Educational Resources Information Center

    Holt, Niles R.

    1989-01-01

    Maintains that Darwin's theory of evolution was more than a science versus religion debate; rather it was a revolutionary concept that influenced numerous social and political ideologies and movements throughout western history. Traces the impact of Darwin's work historically, utilizing a holistic approach. (RW)

  19. Evolution of Osmolyte Systems.

    ERIC Educational Resources Information Center

    Banfalvi, Gaspar

    1991-01-01

    Osmotic aspects of aqueous solutions that are usually disregarded in biochemistry textbooks are presented. This article discusses the osmolarity of seawater, evolution of organisms over geological time, ionic adaptation of cells, ionic concentrations in bacteria, osmolytes and blood electrolytes in water-stressed organisms and land vertebrates,…

  20. The Evolution of Behavior.

    ERIC Educational Resources Information Center

    Smith, John Maynard

    1978-01-01

    The topic of altruistic behavior is an important one in studying the evolution of behavior. It is questioned whether natural selection can actually favor patterns of behavior that apparently do not favor the survival of the individual. Game theory models are presented to help explore the problem. (MA)

  1. Cluster Physics & Evolution

    NASA Astrophysics Data System (ADS)

    Nagai, Daisuke; Arnaud, Monique; Dasadia, Sarthak; McDonald, Michael; Mitsuishi, Ikuyuki; Morandi, Andrea

    Recent advances in X-ray and microwave observations have provided unprecedented insights into the structure and evolution of the hot X-ray emitting plasma from their cores to the virialization region in outskirts of galaxy clusters. Recent Sunyaev-Zel'dovich (SZ) surveys (ACT, Planck, SPT) have provided new cluster catalogs, significantly expanding coverage of the mass-redshift plane, while Chandra and XMM-Newton X-ray follow-up programs have improved our understanding of cluster physics and evolution as well as the surveys themselves. However, the current cluster-based cosmological constraints are still limited by uncertainties in cluster astrophysics. In order to exploit the statistical power of the current and upcoming X-ray and microwave cluster surveys, it is critical to improve our understanding of the structure and evolution of the hot X-ray emitting intracluster medium (ICM). In this session, we discussed recent advances in observations and simulations of galaxy clusters, with highlights on (i) the evolution of ICM profiles and scaling relations, (ii) physical processes operating in the outskirts of galaxy clusters, and (iii) impact of mergers on the ICM structure in groups and clusters.

  2. Evolution in Action

    ERIC Educational Resources Information Center

    Dennis, Mike; Duggan, Adrienne; McGregor, Deb

    2014-01-01

    Evolution and inheritance appear in the new National Science Curriculum for England, which comes into effect from September 2014. In the curriculum documents, it is expected that pupils in year 6 (ages 10-11) should be taught to: (1) recognise that living things have changed over time; (2) recognise that living things produce offspring of the same…

  3. Evolution. Teacher's Guide.

    ERIC Educational Resources Information Center

    Bershad, Carol

    This teacher's guide was developed to assist teachers in the use of multimedia resources for the Public Broadcasting System (PBS) program, "Evolution." Each unit uses an inquiry-based approach to meet the National Science Education Standards. Units include: (1) "What is the Nature of Science?"; (2) "Who Was Charles Darwin?"; (3) "What is the…

  4. The Evolution of Darwinism.

    ERIC Educational Resources Information Center

    Stebbins, G. Ledyard; Ayala, Francisco J.

    1985-01-01

    Recent developments in molecular biology and new interpretations of the fossil record are gradually altering and adding to Charles Darwin's theory, which has been the standard view of the process of evolution for 40 years. Several of these developments and interpretations are identified and discussed. (JN)

  5. Human Development, Human Evolution.

    ERIC Educational Resources Information Center

    Smillie, David

    One of the truly remarkable events in human evolution is the unprecedented increase in the size of the brain of "Homo" over a brief span of 2 million years. It would appear that some significant selective pressure or opportunity presented itself to this branch of the hominid line and caused a rapid increase in the brain, introducing a…

  6. Evolution Projects Yield Results

    ERIC Educational Resources Information Center

    Sparks, Sarah D.

    2010-01-01

    When a federal court in 2005 rejected an attempt by the Dover, Pennsylvania, school board to introduce intelligent design as an alternative to evolution to explain the development of life on Earth, it sparked a renaissance in involvement among scientists in K-12 science instruction. Now, some of those teaching programs, studies, and research…

  7. The timetable of evolution

    PubMed Central

    Knoll, Andrew H.; Nowak, Martin A.

    2017-01-01

    The integration of fossils, phylogeny, and geochronology has resulted in an increasingly well-resolved timetable of evolution. Life appears to have taken root before the earliest known minimally metamorphosed sedimentary rocks were deposited, but for a billion years or more, evolution played out beneath an essentially anoxic atmosphere. Oxygen concentrations in the atmosphere and surface oceans first rose in the Great Oxygenation Event (GOE) 2.4 billion years ago, and a second increase beginning in the later Neoproterozoic Era [Neoproterozoic Oxygenation Event (NOE)] established the redox profile of modern oceans. The GOE facilitated the emergence of eukaryotes, whereas the NOE is associated with large and complex multicellular organisms. Thus, the GOE and NOE are fundamental pacemakers for evolution. On the time scale of Earth’s entire 4 billion–year history, the evolutionary dynamics of the planet’s biosphere appears to be fast, and the pace of evolution is largely determined by physical changes of the planet. However, in Phanerozoic ecosystems, interactions between new functions enabled by the accumulation of characters in a complex regulatory environment and changing biological components of effective environments appear to have an important influence on the timing of evolutionary innovations. On the much shorter time scale of transient environmental perturbations, such as those associated with mass extinctions, rates of genetic accommodation may have been limiting for life. PMID:28560344

  8. The Evolution of Cooperation.

    ERIC Educational Resources Information Center

    Dugatkin, Lee Alan

    1997-01-01

    Outlines the four paths to the evolution and maintenance of cooperative behavior and provides two stories highlighting each path. Discusses reciprocity, byproduct mutualism, kin-selected cooperation, and group-selected cooperation. Presents some thoughts on where the study of animal cooperation might head in the future. Contains 67 references.…

  9. Evolution of lifespan.

    PubMed

    Neill, David

    2014-10-07

    Present-day evolutionary theory, modern synthesis and evo-devo, appear to explain evolution. There remain however several points of contention. These include: biological time, direction, macroevolution verses microevolution, ageing and the extent of internal as opposed to external mediation. A new theoretical model for the control of biological time in vertebrates/bilaterians is introduced. Rather than biological time being controlled solely by a molecular cascade domino effect, it is suggested there is also an intracellular oscillatory clock. This clock (life's timekeeper) is synchronised across all cells in an organism and runs at a constant frequency throughout life. Slower frequencies extend lifespan, increase body/brain size and advance behaviour. They also create a time void which could aid additional evolutionary change. Faster frequencies shorten lifespan, reduce body/brain size and diminish behaviour. They are therefore less likely to mediate evolution in vertebrates/mammals. It is concluded that in vertebrates, especially mammals, there is a direction in evolution towards longer lifespan/advanced behaviour. Lifespan extension could equate with macroevolution and subsequent modifications with microevolution. As life's timekeeper controls the rate of ageing it constitutes a new genetic theory of ageing. Finally, as lifespan extension is internally mediated, this suggests a major role for internal mediation in evolution. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Evolution and Flow.

    ERIC Educational Resources Information Center

    Csikszentmihalyi, Mihaly

    1997-01-01

    Presents flow theory in the context of evolution. Defines the elements of "flow" and contends that flow results in an optimal state of inner harmony which improves one's chance for survival. Identifies consequences of flow for creativity, peak performance, talent development, productivity, self-esteem, and stress reduction. Examines the…

  11. Evolution Perception with Metaphors

    ERIC Educational Resources Information Center

    Yilmaz, Fatih

    2016-01-01

    The main objective of this research is to find out how the teacher candidates who graduated from the Faculty of Theology and study in pedagogical formation program perceive the theory of evolution. Having a descriptive characteristic, this research is conducted with 63 Faculty of Theology graduate teacher candidates of which 36 is women and 27 is…

  12. Voices for Evolution.

    ERIC Educational Resources Information Center

    McCollister, Betty, Ed.

    The creation/evolution controversy can be best thought of as a contest over control of a portion of educational policy. Scientists do not dispute the right of fundamentalist Christians to believe that Genesis is a history and a science textbook. The difficulty arises when fundamentalists seek to bring their sectarian religious faith into biology…

  13. Evolution and Friendship

    ERIC Educational Resources Information Center

    Mena-Werth, Jose

    2005-01-01

    In 1925, Williams Jennings Bryan, a former congressman from Nebraska and a former Secretary of State under Woodrow Wilson, spent two agonizing weeks defending his religious faith that cost him his life a month after. Bryan was a prosecutor of high school teacher John Scopes, who had violated Tennessee state law by teaching the theory of evolution.…

  14. Crustal Evolution Introduced.

    ERIC Educational Resources Information Center

    Stoever, Edward C., Jr.; Korporaal, Arie R.

    1979-01-01

    Detailed are the origins, development, and implementation of the Crustal Evolution Education Project (CEEP). This group has produced, for use in earth science and other classes in grades 8-10, a series of instructional modules based on current scientific research in the composition, history, and processes of the earth's crust. (BT)

  15. Collection Evaluation and Evolution

    NASA Technical Reports Server (NTRS)

    Habermann, Ted; Kozimor, John

    2017-01-01

    We will review metadata evaluation tools and share results from our most recent CMR analysis. We will demonstrate results using Google spreadsheets and present new results in terms of number of records that include specific content. We will show evolution of UMM-compliance over time and also show results of comparing various CMR collections (NASA, non-NASA, and SciOps).

  16. Software Architecture Evolution

    ERIC Educational Resources Information Center

    Barnes, Jeffrey M.

    2013-01-01

    Many software systems eventually undergo changes to their basic architectural structure. Such changes may be prompted by new feature requests, new quality attribute requirements, changing technology, or other reasons. Whatever the causes, architecture evolution is commonplace in real-world software projects. Today's software architects, however,…

  17. Evolution: Sex Limits Adaptation.

    PubMed

    Nosil, Patrik

    2015-07-20

    Evolution is affected by survival of individuals and by mate choice, but how sexual selection affects adaptation remains unclear. A new study finds that sexual selection can limit adaptation by causing male-induced harm to females and thus opposing natural selection. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Early cellular evolution.

    NASA Technical Reports Server (NTRS)

    Margulis, L.

    1972-01-01

    Study of the evolutionary developments that occurred subsequent to the origin of ancestral cells. Microbial physiology and ecology are potential sharp tools for shaping concepts of microbial evolution. Some popular unjustified assumptions are discussed. It is considered that certain principles derived mainly from the advances of molecular biology can be used to order the natural groups (genera) of extant prokaryotes and their patterns phylogenetically.

  19. The timetable of evolution.

    PubMed

    Knoll, Andrew H; Nowak, Martin A

    2017-05-01

    The integration of fossils, phylogeny, and geochronology has resulted in an increasingly well-resolved timetable of evolution. Life appears to have taken root before the earliest known minimally metamorphosed sedimentary rocks were deposited, but for a billion years or more, evolution played out beneath an essentially anoxic atmosphere. Oxygen concentrations in the atmosphere and surface oceans first rose in the Great Oxygenation Event (GOE) 2.4 billion years ago, and a second increase beginning in the later Neoproterozoic Era [Neoproterozoic Oxygenation Event (NOE)] established the redox profile of modern oceans. The GOE facilitated the emergence of eukaryotes, whereas the NOE is associated with large and complex multicellular organisms. Thus, the GOE and NOE are fundamental pacemakers for evolution. On the time scale of Earth's entire 4 billion-year history, the evolutionary dynamics of the planet's biosphere appears to be fast, and the pace of evolution is largely determined by physical changes of the planet. However, in Phanerozoic ecosystems, interactions between new functions enabled by the accumulation of characters in a complex regulatory environment and changing biological components of effective environments appear to have an important influence on the timing of evolutionary innovations. On the much shorter time scale of transient environmental perturbations, such as those associated with mass extinctions, rates of genetic accommodation may have been limiting for life.

  20. Human Development, Human Evolution.

    ERIC Educational Resources Information Center

    Smillie, David

    One of the truly remarkable events in human evolution is the unprecedented increase in the size of the brain of "Homo" over a brief span of 2 million years. It would appear that some significant selective pressure or opportunity presented itself to this branch of the hominid line and caused a rapid increase in the brain, introducing a…

  1. Decentralized Software Evolution

    DTIC Science & Technology

    2003-09-01

    Institute for Software Research University of California, Irvine www.isr.uci.edu/tech-reports.html Peyman Oreizy University of California, Irvine... Peyman Oreizy and Richard N. Taylor Institute for Software Research University of California, Irvine Irvine, CA 92697-3425 USA {peymano, taylor...mechanisms that enforce cooperation among Decentralized Software Evolution Peyman Oreizy and Richard N. Taylor Institute for Software Research

  2. Evolution: Skipping School

    PubMed Central

    Bell, Alison M.

    2014-01-01

    Some individual fish like to be close together in ‘schools’, while other individuals like to be alone. A pair of recent papers dissects the genetic basis of schooling behavior, showing that genetic changes in sensory systems are involved when this social behavior is lost during evolution. PMID:24112981

  3. Evolution Projects Yield Results

    ERIC Educational Resources Information Center

    Sparks, Sarah D.

    2010-01-01

    When a federal court in 2005 rejected an attempt by the Dover, Pennsylvania, school board to introduce intelligent design as an alternative to evolution to explain the development of life on Earth, it sparked a renaissance in involvement among scientists in K-12 science instruction. Now, some of those teaching programs, studies, and research…

  4. Early cellular evolution.

    NASA Technical Reports Server (NTRS)

    Margulis, L.

    1972-01-01

    Study of the evolutionary developments that occurred subsequent to the origin of ancestral cells. Microbial physiology and ecology are potential sharp tools for shaping concepts of microbial evolution. Some popular unjustified assumptions are discussed. It is considered that certain principles derived mainly from the advances of molecular biology can be used to order the natural groups (genera) of extant prokaryotes and their patterns phylogenetically.

  5. Evolution of Osmolyte Systems.

    ERIC Educational Resources Information Center

    Banfalvi, Gaspar

    1991-01-01

    Osmotic aspects of aqueous solutions that are usually disregarded in biochemistry textbooks are presented. This article discusses the osmolarity of seawater, evolution of organisms over geological time, ionic adaptation of cells, ionic concentrations in bacteria, osmolytes and blood electrolytes in water-stressed organisms and land vertebrates,…

  6. The Evolution of Empathy

    ERIC Educational Resources Information Center

    Hackney, Harold

    1978-01-01

    Therapeutic empathy has been an often-used construct by counseling professionals. Through that usage, the term has evolved in meaning and significance from its original presentation by Carl Rogers. This article traces that evolution by identifying its users and contributors over the past 20 years. (Author)

  7. Evolution and Friendship

    ERIC Educational Resources Information Center

    Mena-Werth, Jose

    2005-01-01

    In 1925, Williams Jennings Bryan, a former congressman from Nebraska and a former Secretary of State under Woodrow Wilson, spent two agonizing weeks defending his religious faith that cost him his life a month after. Bryan was a prosecutor of high school teacher John Scopes, who had violated Tennessee state law by teaching the theory of evolution.…

  8. Evolution and the Law

    ERIC Educational Resources Information Center

    Mayer, William V.

    1973-01-01

    Some court cases and legislative bills have been filed in states to legalize the use of the creationist view (of life forms on earth) in biology textbooks superseding the organic theory of evolution. The law has not yet accepted the religious viewpoint. (PS)

  9. Evolution in Action

    ERIC Educational Resources Information Center

    Dennis, Mike; Duggan, Adrienne; McGregor, Deb

    2014-01-01

    Evolution and inheritance appear in the new National Science Curriculum for England, which comes into effect from September 2014. In the curriculum documents, it is expected that pupils in year 6 (ages 10-11) should be taught to: (1) recognise that living things have changed over time; (2) recognise that living things produce offspring of the same…

  10. Evolution and Religion

    ERIC Educational Resources Information Center

    Strickberger, Monroe W.

    1973-01-01

    The relationship between the two concepts (evolution, religion) from an historical and social view is discussed. The concepts are seen to respond differently to the various needs of society, with considerable conflict between them in areas which involve the justification of religious beliefs. (Author/EB)

  11. Titan Polar Landscape Evolution

    NASA Technical Reports Server (NTRS)

    Moore, Jeffrey M.

    2016-01-01

    With the ongoing Cassini-era observations and studies of Titan it is clear that the intensity and distribution of surface processes (particularly fluvial erosion by methane and Aeolian transport) has changed through time. Currently however, alternate hypotheses substantially differ among specific scenarios with respect to the effects of atmospheric evolution, seasonal changes, and endogenic processes. We have studied the evolution of Titan's polar region through a combination of analysis of imaging, elevation data, and geomorphic mapping, spatially explicit simulations of landform evolution, and quantitative comparison of the simulated landscapes with corresponding Titan morphology. We have quantitatively evaluated alternate scenarios for the landform evolution of Titan's polar terrain. The investigations have been guided by recent geomorphic mapping and topographic characterization of the polar regions that are used to frame hypotheses of process interactions, which have been evaluated using simulation modeling. Topographic information about Titan's polar region is be based on SAR-Topography and altimetry archived on PDS, SAR-based stereo radar-grammetry, radar-sounding lake depth measurements, and superposition relationships between geomorphologic map units, which we will use to create a generalized topographic map.

  12. Software Architecture Evolution

    ERIC Educational Resources Information Center

    Barnes, Jeffrey M.

    2013-01-01

    Many software systems eventually undergo changes to their basic architectural structure. Such changes may be prompted by new feature requests, new quality attribute requirements, changing technology, or other reasons. Whatever the causes, architecture evolution is commonplace in real-world software projects. Today's software architects, however,…

  13. Glossogeny and phylogeny: cultural evolution meets genetic evolution.

    PubMed

    Fitch, W Tecumseh

    2008-08-01

    Evolutionary theorists since Darwin have been interested in the parallels and interactions between biological and cultural evolution. Recent applications of empirical techniques originally developed to analyze molecular genetic data to linguistic data offer new insights into the historical evolution of language, revealing fascinating parallels between language change and biological evolution. This work offers considerable potential toward unified theories of genetic and cultural change.

  14. Evolution as Fact and Theory.

    ERIC Educational Resources Information Center

    Gould, Stephen Jay

    1981-01-01

    This essay by a Harvard evolutionist presents viewpoints concerning the creationists' arguments against evolutionary biology. Semantics regarding "facts" and "theory" of evolution are examined, examples are cited of creationist argument, and arguments for evolution are presented. (CS)

  15. Viral Evolution Core | FNLCR Staging

    Cancer.gov

    Brandon F. Keele, Ph.D. PI/Senior Principal Investigator, Retroviral Evolution Section Head, Viral Evolution Core Leidos Biomedical Research, Inc. Frederick National Laboratory for Cancer Research Frederick, MD 21702-1201 Tel: 301-846-173

  16. "New" Persuasive Evidence for Evolution.

    ERIC Educational Resources Information Center

    Max, Edward E.

    1998-01-01

    Discusses some new evidence for evolution that might be useful in persuading students who question the scientific basis for evolution. Draws on findings from the fields of molecular biology and genetics. (DDR)

  17. Evolution as Fact and Theory.

    ERIC Educational Resources Information Center

    Gould, Stephen Jay

    1981-01-01

    This essay by a Harvard evolutionist presents viewpoints concerning the creationists' arguments against evolutionary biology. Semantics regarding "facts" and "theory" of evolution are examined, examples are cited of creationist argument, and arguments for evolution are presented. (CS)

  18. Evolution of Brain and Language

    ERIC Educational Resources Information Center

    Schoenemann, P. Thomas

    2009-01-01

    The evolution of language and the evolution of the brain are tightly interlinked. Language evolution represents a special kind of adaptation, in part because language is a complex behavior (as opposed to a physical feature) but also because changes are adaptive only to the extent that they increase either one's understanding of others, or one's…

  19. Evolution of Brain and Language

    ERIC Educational Resources Information Center

    Schoenemann, P. Thomas

    2009-01-01

    The evolution of language and the evolution of the brain are tightly interlinked. Language evolution represents a special kind of adaptation, in part because language is a complex behavior (as opposed to a physical feature) but also because changes are adaptive only to the extent that they increase either one's understanding of others, or one's…

  20. Expanding the Understanding of Evolution

    ERIC Educational Resources Information Center

    Musante, Susan

    2011-01-01

    Originally designed for K-12 teachers, the Understanding Evolution (UE) Web site ("www.understandingevolution.org") is a one-stop shop for all of a teacher's evolution education needs, with lesson plans, teaching tips, lists of common evolution misconceptions, and much more. However, during the past five years, the UE project team learned that…

  1. Expanding the Understanding of Evolution

    ERIC Educational Resources Information Center

    Musante, Susan

    2011-01-01

    Originally designed for K-12 teachers, the Understanding Evolution (UE) Web site ("www.understandingevolution.org") is a one-stop shop for all of a teacher's evolution education needs, with lesson plans, teaching tips, lists of common evolution misconceptions, and much more. However, during the past five years, the UE project team learned that…

  2. Type Evolution and Instance Adaptation

    DTIC Science & Technology

    1992-06-01

    Schema evolution support is an important facility for object-oriented database (OODB) systems. While existing OODB systems provide for limited forms...of evolution , including modification to the database schema and reorganization of affected instances, we find their support insufficient. Specific... evolution of class definitions and the adaptation of existing, persistent instances to those new definitions.

  3. Fla. Panel's Evolution Vote Hailed

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2008-01-01

    This article reports on how the compromise hammered out in Florida recently over the treatment of evolution in the state's science classrooms is winning praise from scientists and educators. The new science standards will refer to evolution as the "scientific theory of evolution." These changes will replace more-general language in the…

  4. The evolution of helicopters

    NASA Astrophysics Data System (ADS)

    Chen, R.; Wen, C. Y.; Lorente, S.; Bejan, A.

    2016-07-01

    Here, we show that during their half-century history, helicopters have been evolving into geometrically similar architectures with surprisingly sharp correlations between dimensions, performance, and body size. For example, proportionalities emerge between body size, engine size, and the fuel load. Furthermore, the engine efficiency increases with the engine size, and the propeller radius is roughly the same as the length scale of the whole body. These trends are in accord with the constructal law, which accounts for the engine efficiency trend and the proportionality between "motor" size and body size in animals and vehicles. These body-size effects are qualitatively the same as those uncovered earlier for the evolution of aircraft. The present study adds to this theoretical body of research the evolutionary design of all technologies [A. Bejan, The Physics of Life: The Evolution of Everything (St. Martin's Press, New York, 2016)].

  5. Kamikazes and cultural evolution.

    PubMed

    Allen-Hermanson, Sean

    2017-02-01

    Is cultural evolution needed to explain altruistic selfsacrifice? Some contend that cultural traits (e.g. beliefs, behaviors, and for some "memes") replicate according to selection processes that have "floated free" from biology. One test case is the example of suicide kamikaze attacks in wartime Japan. Standard biological mechanisms-such as reciprocal altruism and kin selection-might not seem to apply here: The suicide pilots did not act on the expectation that others would reciprocate, and they were supposedly sacrificing themselves for country and emperor, not close relatives. Yet an examination of both the historical record and the demands of evolutionary theory suggest the kamikaze phenomenon does not cry out for explanation in terms of a special non-biological selection process. This weakens the case for cultural evolution, and has interesting implications for our understanding of altruistic self-sacrifice.

  6. The metaphysics of evolution

    PubMed Central

    2017-01-01

    This paper briefly describes process metaphysics, and argues that it is better suited for describing life than the more standard thing, or substance, metaphysics. It then explores the implications of process metaphysics for conceptualizing evolution. After explaining what it is for an organism to be a process, the paper takes up the Hull/Ghiselin thesis of species as individuals and explores the conditions under which a species or lineage could constitute an individual process. It is argued that only sexual species satisfy these conditions, and that within sexual species the degree of organization varies. This, in turn, has important implications for species' evolvability. One important moral is that evolution will work differently in different biological domains. PMID:28839921

  7. The metaphysics of evolution.

    PubMed

    Dupré, John

    2017-10-06

    This paper briefly describes process metaphysics, and argues that it is better suited for describing life than the more standard thing, or substance, metaphysics. It then explores the implications of process metaphysics for conceptualizing evolution. After explaining what it is for an organism to be a process, the paper takes up the Hull/Ghiselin thesis of species as individuals and explores the conditions under which a species or lineage could constitute an individual process. It is argued that only sexual species satisfy these conditions, and that within sexual species the degree of organization varies. This, in turn, has important implications for species' evolvability. One important moral is that evolution will work differently in different biological domains.

  8. Anatomy of Scientific Evolution

    PubMed Central

    Yun, Jinhyuk; Kim, Pan-Jun; Jeong, Hawoong

    2015-01-01

    The quest for historically impactful science and technology provides invaluable insight into the innovation dynamics of human society, yet many studies are limited to qualitative and small-scale approaches. Here, we investigate scientific evolution through systematic analysis of a massive corpus of digitized English texts between 1800 and 2008. Our analysis reveals great predictability for long-prevailing scientific concepts based on the levels of their prior usage. Interestingly, once a threshold of early adoption rates is passed even slightly, scientific concepts can exhibit sudden leaps in their eventual lifetimes. We developed a mechanistic model to account for such results, indicating that slowly-but-commonly adopted science and technology surprisingly tend to have higher innate strength than fast-and-commonly adopted ones. The model prediction for disciplines other than science was also well verified. Our approach sheds light on unbiased and quantitative analysis of scientific evolution in society, and may provide a useful basis for policy-making. PMID:25671617

  9. Thermal evolution of Venus

    NASA Technical Reports Server (NTRS)

    Arkani-Hamed, J.; Toksoz, M. N.

    1984-01-01

    A modification of the Boussinesq fluid assumption is the basis of the present theory of three-dimensional and finite amplitude convection in a viscous spherical shell with temperature- and pressure-dependent physical parameters. The theory is applied to the definition of thermal evolution models for Venus which emphasize the effects of certain physical parameters on thermal evolution, rather than the specific thermal history of the planet. It is suggested that a significant portion of the present temperature in the mantle and surface heat flux of Venus is due to the decay of a high temperature that was established in the planet at the completion of its core formation, and that Venus has been highly convective over the course of its history, until about 0.5 Ga ago.

  10. Evolution of intrafamilial interactions.

    PubMed Central

    Lynch, M

    1987-01-01

    A theory for the evolution of behavioral interactions among relatives is developed that allows for genetic correlations between the types of behavior that are expressed in different social contexts. Both theoretical and empirical considerations indicate that such genetic constraints will almost certainly be common in natural populations. It is shown that when genetic correlations between elements of social behavior exist, Hamilton's rule inaccurately describes the conditions for evolution by way of kin selection. The direction in which social organization evolves is a delicate function of the genetic covariance structure among behaviors expressed as an offspring, sibling, parent, etc. A change in this covariance structure caused by random genetic drift or by a change in environment for a population exhibiting genotype-environment interaction can cause the population to suddenly cross a threshold into a new selective domain. Consequently, radical changes in social organization may arise between closely related species without any major shift in selective pressures external to the population. Images PMID:3479804

  11. Epigenetics and brain evolution.

    PubMed

    Keverne, Eric B

    2011-04-01

    Fundamental aspects of mammalian brain evolution occurred in the context of viviparity and placentation brought about by the epigenetic regulation of imprinted genes. Since the fetal placenta hormonally primes the maternal brain, two genomes in one individual are transgenerationally co-adapted to ensure maternal care and nurturing. Advanced aspects of neocortical brain evolution has shown very few genetic changes between monkeys and humans. Although these lineages diverged at approximately the same time as the rat and mouse (20 million years ago), synonymous sequence divergence between the rat and mouse is double that when comparing monkey with human sequences. Paradoxically, encephalization of rat and mouse are remarkably similar, while comparison of the human and monkey shows the human cortex to be three times the size of the monkey. This suggests an element of genetic stability between the brains of monkey and man with a greater emphasis on epigenetics providing adaptable variability.

  12. Algorithms, games, and evolution

    PubMed Central

    Chastain, Erick; Livnat, Adi; Papadimitriou, Christos; Vazirani, Umesh

    2014-01-01

    Even the most seasoned students of evolution, starting with Darwin himself, have occasionally expressed amazement that the mechanism of natural selection has produced the whole of Life as we see it around us. There is a computational way to articulate the same amazement: “What algorithm could possibly achieve all this in a mere three and a half billion years?” In this paper we propose an answer: We demonstrate that in the regime of weak selection, the standard equations of population genetics describing natural selection in the presence of sex become identical to those of a repeated game between genes played according to multiplicative weight updates (MWUA), an algorithm known in computer science to be surprisingly powerful and versatile. MWUA maximizes a tradeoff between cumulative performance and entropy, which suggests a new view on the maintenance of diversity in evolution. PMID:24979793

  13. QCD Evolution 2015

    NASA Astrophysics Data System (ADS)

    These are the proceedings of the QCD Evolution 2015 Workshop which was held 26-30 May, 2015 at Jefferson Lab, Newport News, Virginia, USA. The workshop is a continuation of a series of workshops held during four consecutive years 2011, 2012, 2013 at Jefferson Lab, and in 2014 in Santa Fe, NM. With the rapid developments in our understanding of the evolution of parton distributions including low-x, TMDs, GPDs, higher-twist correlation functions, and the associated progress in perturbative QCD, lattice QCD and effective field theory techniques we look forward with great enthusiasm to the 2015 meeting. A special attention was also paid to participation of experimentalists as the topics discussed are of immediate importance for the JLab 12 experimental program and a future Electron Ion Collider.

  14. Evolution of catalytic function

    NASA Technical Reports Server (NTRS)

    Joyce, G. F.

    1993-01-01

    An RNA-based evolution system was constructed in the laboratory and used to develop RNA enzymes with novel catalytic function. By controlling the nature of the catalytic task that the molecules must perform in order to survive, it is possible to direct the evolving population toward the expression of some desired catalytic behavior. More recently, this system has been coupled to an in vitro translation procedure, raising the possibility of evolving protein enzymes in the laboratory to produce novel proteins with desired catalytic properties. The aim of this line of research is to reduce darwinian evolution, the fundamental process of biology, to a laboratory procedure that can be made to operate in the service of organic synthesis.

  15. Evolution of catalytic function

    NASA Technical Reports Server (NTRS)

    Joyce, G. F.

    1993-01-01

    An RNA-based evolution system was constructed in the laboratory and used to develop RNA enzymes with novel catalytic function. By controlling the nature of the catalytic task that the molecules must perform in order to survive, it is possible to direct the evolving population toward the expression of some desired catalytic behavior. More recently, this system has been coupled to an in vitro translation procedure, raising the possibility of evolving protein enzymes in the laboratory to produce novel proteins with desired catalytic properties. The aim of this line of research is to reduce darwinian evolution, the fundamental process of biology, to a laboratory procedure that can be made to operate in the service of organic synthesis.

  16. Evolution of mycorrhiza systems

    NASA Astrophysics Data System (ADS)

    Cairney, J. W. G.

    Most terrestrial plants live in mutualistic symbiosis with root-infecting mycorrhizal fungi. Fossil records and molecular clock dating suggest that all extant land plants have arisen from an ancestral arbuscular mycorrhizal condition. Arbuscular mycorrhizas evolved concurrently with the first colonisation of land by plants some 450-500 million years ago and persist in most extant plant taxa. Ectomycorrhizas (about 200million years ago) and ericoid mycorrhizas (about 100million years ago) evolved subsequently as the organic matter content of some ancient soils increased and sclerophyllous vegetation arose as a response to nutrient-poor soils respectively. Mycorrhizal associations appear to be the result of relatively diffuse coevolutionary processes. While early events in the evolution of mycorrhizal symbioses may have involved reciprocal genetic changes in ancestral plants and free-living fungi, available evidence points largely to ongoing parallel evolution of the partners in response to environmental change.

  17. The evolution of dinosaurs.

    PubMed

    Sereno, P C

    1999-06-25

    The ascendancy of dinosaurs on land near the close of the Triassic now appears to have been as accidental and opportunistic as their demise and replacement by therian mammals at the end of the Cretaceous. The dinosaurian radiation, launched by 1-meter-long bipeds, was slower in tempo and more restricted in adaptive scope than that of therian mammals. A notable exception was the evolution of birds from small-bodied predatory dinosaurs, which involved a dramatic decrease in body size. Recurring phylogenetic trends among dinosaurs include, to the contrary, increase in body size. There is no evidence for co-evolution between predators and prey or between herbivores and flowering plants. As the major land masses drifted apart, dinosaurian biogeography was molded more by regional extinction and intercontinental dispersal than by the breakup sequence of Pangaea.

  18. Clonal evolution in leukemia.

    PubMed

    Ferrando, Adolfo A; López-Otín, Carlos

    2017-10-06

    Human leukemias are liquid malignancies characterized by diffuse infiltration of the bone marrow by transformed hematopoietic progenitors. The accessibility of tumor cells obtained from peripheral blood or through bone marrow aspirates, together with recent advances in cancer genomics and single-cell molecular analysis, have facilitated the study of clonal populations and their genetic and epigenetic evolution over time with unprecedented detail. The results of these analyses challenge the classic view of leukemia as a clonal homogeneous diffuse tumor and introduce a more complex and dynamic scenario. In this review, we present current concepts on the role of clonal evolution in lymphoid and myeloid leukemia as a driver of tumor initiation, disease progression and relapse. We also discuss the implications of these concepts in our understanding of the evolutionary mechanisms involved in leukemia transformation and therapy resistance.

  19. Evolution of intracellular pathogens.

    PubMed

    Casadevall, Arturo

    2008-01-01

    The evolution of intracellular pathogens is considered in the context of ambiguities in basic definitions and the diversity of host-microbe interactions. Intracellular pathogenesis is a subset of a larger world of host-microbe interactions that includes amoeboid predation and endosymbiotic existence. Intracellular pathogens often reveal genome reduction. Despite the uniqueness of each host-microbe interaction, there are only a few general solutions to the problem of intracellular survival, especially in phagocytic cells. Similarities in intracellular pathogenic strategies between phylogenetically distant microbes suggest convergent evolution. For discerning such patterns, it is useful to consider whether the microbe is acquired from another host or directly from the environment. For environmentally acquired microbes, biotic pressures, such as amoeboid predators, may select for the capacity for virulence. Although often viewed as a specialized adaptation, the capacity for intracellular survival may be widespread among microbes, thus questioning whether the intracellular lifestyle warrants a category of special distinctiveness.

  20. Anatomy of scientific evolution.

    PubMed

    Yun, Jinhyuk; Kim, Pan-Jun; Jeong, Hawoong

    2015-01-01

    The quest for historically impactful science and technology provides invaluable insight into the innovation dynamics of human society, yet many studies are limited to qualitative and small-scale approaches. Here, we investigate scientific evolution through systematic analysis of a massive corpus of digitized English texts between 1800 and 2008. Our analysis reveals great predictability for long-prevailing scientific concepts based on the levels of their prior usage. Interestingly, once a threshold of early adoption rates is passed even slightly, scientific concepts can exhibit sudden leaps in their eventual lifetimes. We developed a mechanistic model to account for such results, indicating that slowly-but-commonly adopted science and technology surprisingly tend to have higher innate strength than fast-and-commonly adopted ones. The model prediction for disciplines other than science was also well verified. Our approach sheds light on unbiased and quantitative analysis of scientific evolution in society, and may provide a useful basis for policy-making.

  1. Geologic evolution of Arizona

    SciTech Connect

    Penny, J.P.; Reynolds, S.J.

    1989-01-01

    Seven years in the making, the 35 papers in this volume summarize the stratigraphic, structural, and tectonic evolution of Arizona from Precambrian through Quaternary time. Intended as a compendium of current knowledge of Arizona geology, the papers synthesize previous work with new data, ideas, and concepts as well as identifying unresolved problems for future research. Emphasis is placed on the geologic evolution of the state as a whole rather than specific local areas. The papers are organized in terms of geologic eras: Proterozoic, Paleozoic, Mesozoic, and Cenozoic. The concluding section offers topical studies in the areas of geophysics, industrial minerals, uranium, oil and gas, geothermal resources, hydrogeology, and environmental geology. California readers will find much of interest in this research volume because many of the tectonic processes that formed Arizona also affected the development of this state.

  2. Relative constraints and evolution

    NASA Astrophysics Data System (ADS)

    Ochoa, Juan G. Diaz

    2014-03-01

    Several mathematical models of evolving systems assume that changes in the micro-states are constrained to the search of an optimal value in a local or global objective function. However, the concept of evolution requires a continuous change in the environment and species, making difficult the definition of absolute optimal values in objective functions. In this paper, we define constraints that are not absolute but relative to local micro-states, introducing a rupture in the invariance of the phase space of the system. This conceptual basis is useful to define alternative mathematical models for biological (or in general complex) evolving systems. We illustrate this concept with a modified Ising model, which can be useful to understand and model problems like the somatic evolution of cancer.

  3. Galaxy evolution. Galactic paleontology.

    PubMed

    Tolstoy, Eline

    2011-07-08

    Individual low-mass stars have very long lives, comparable to the age of the universe, and can thus be used to probe ancient star formation. At present, such stars can be identified and studied only in the Milky Way and in the very closest of our neighboring galaxies, which are predominantly small dwarf galaxies. These nearby ancient stars are a fossil record that can provide detailed information about the physical processes that dominated the epoch of galaxy formation and subsequent evolution.

  4. Software Architecture Evolution

    DTIC Science & Technology

    2013-12-01

    adequately. Swanson’s taxonomy was so influential that it was incorporated, many years later, into ISO /IEC 14764 [109, § 6.2], an international standard on...borrow the software maintenance typology from ISO /IEC 14764 for their “Need for Evolution” dimension. I am aware of one empirical study that has examined...Integration. The feature prototypes were designed to allow us to develop, in iso - lation, the main features required for an evolution planning plug-in

  5. Landscape evolution of Antarctica

    USGS Publications Warehouse

    Jamieson, S.S.R.; Sugden, D.E.

    2007-01-01

    shelf before retreating to its present dimensions at ~13.5 Ma. Subsequent changes in ice extent have been forced mainly by sea-level change. Weathering rates of exposed bedrock have been remarkably slow at high elevations around the margin of East Antarctica under the hyperarid polar climate of the last ~13.5 Ma, offering potential for a long quantitative record of ice-sheet evolution with techniques such as cosmogenic isotope analysis

  6. US Space Shuttle evolution

    NASA Technical Reports Server (NTRS)

    Teixeira, Charles

    1989-01-01

    The long term systematic series of upgrades and enhancements needed to insure that the Space Shuttle remains a viable, cost-effective transportation system are discussed. A candidate Space Shuttle evolution strategy is presented. It emphasizes enhanced reliability, crew safety, reduced operations costs and enhanced capabilities required to meet projected long-range requirements. The strategy includes definition of long-term goals and requirements, potential hardware and operation enhancements, and addresses the issues of fleet size and utilization.

  7. Chromosomal evolution in Rodentia.

    PubMed

    Romanenko, S A; Perelman, P L; Trifonov, V A; Graphodatsky, A S

    2012-01-01

    Rodentia is the most species-rich mammalian order and includes several important laboratory model species. The amount of new information on karyotypic and phylogenetic relations within and among rodent taxa is rapidly increasing, but a synthesis of these data is currently lacking. Here, we have integrated information drawn from conventional banding studies, recent comparative painting investigations and molecular phylogenetic reconstructions of different rodent taxa. This permitted a revision of several ancestral karyotypic reconstructions, and a more accurate depiction of rodent chromosomal evolution.

  8. Epistasis in protein evolution

    PubMed Central

    Starr, Tyler N.

    2016-01-01

    Abstract The structure, function, and evolution of proteins depend on physical and genetic interactions among amino acids. Recent studies have used new strategies to explore the prevalence, biochemical mechanisms, and evolutionary implications of these interactions—called epistasis—within proteins. Here we describe an emerging picture of pervasive epistasis in which the physical and biological effects of mutations change over the course of evolution in a lineage‐specific fashion. Epistasis can restrict the trajectories available to an evolving protein or open new paths to sequences and functions that would otherwise have been inaccessible. We describe two broad classes of epistatic interactions, which arise from different physical mechanisms and have different effects on evolutionary processes. Specific epistasis—in which one mutation influences the phenotypic effect of few other mutations—is caused by direct and indirect physical interactions between mutations, which nonadditively change the protein's physical properties, such as conformation, stability, or affinity for ligands. In contrast, nonspecific epistasis describes mutations that modify the effect of many others; these typically behave additively with respect to the physical properties of a protein but exhibit epistasis because of a nonlinear relationship between the physical properties and their biological effects, such as function or fitness. Both types of interaction are rampant, but specific epistasis has stronger effects on the rate and outcomes of evolution, because it imposes stricter constraints and modulates evolutionary potential more dramatically; it therefore makes evolution more contingent on low‐probability historical events and leaves stronger marks on the sequences, structures, and functions of protein families. PMID:26833806

  9. ENVIRONMENT AND PROTOSTELLAR EVOLUTION

    SciTech Connect

    Zhang, Yichen; Tan, Jonathan C.

    2015-04-01

    Even today in our Galaxy, stars form from gas cores in a variety of environments, which may affect the properties of the resulting star and planetary systems. Here, we study the role of pressure, parameterized via ambient clump mass surface density, on protostellar evolution and appearance, focusing on low-mass Sun-like stars and considering a range of conditions from relatively low pressure filaments in Taurus, to intermediate pressures of cluster-forming clumps like the Orion Nebula Cluster, to very high pressures that may be found in the densest infrared dark clouds or in the Galactic center. We present unified analytic and numerical models for the collapse of prestellar cores, accretion disks, protostellar evolution, and bipolar outflows, coupled with radiative transfer calculations and a simple astrochemical model to predict CO gas-phase abundances. Prestellar cores in high-pressure environments are smaller and denser and thus collapse with higher accretion rates and efficiencies, resulting in higher luminosity protostars with more powerful outflows. The protostellar envelope is heated to warmer temperatures, affecting infrared morphologies (and thus classification) and astrochemical processes like CO depletion onto dust grain ice mantles (and thus CO morphologies). These results have general implications for star and planet formation, especially via their effect on astrochemical and dust grain evolution during infall to and through protostellar accretion disks.

  10. Thermodynamical Arguments Against Evolution

    NASA Astrophysics Data System (ADS)

    Rosenhouse, Jason

    2017-03-01

    The argument that the second law of thermodynamics contradicts the theory of evolution has recently been revived by anti-evolutionists. In its basic form, the argument asserts that whereas evolution implies that there has been an increase in biological complexity over time, the second law, a fundamental principle of physics, shows this to be impossible. Scientists have responded primarily by noting that the second law does not rule out increases in complexity in open systems, and since the Earth receives energy from the Sun, it is an open system. This reply is correct as far as it goes, and it adequately rebuts the most crude versions of the second law argument. However, it is insufficient against more sophisticated versions, and it leaves many relevant aspects of thermodynamics unexplained. We shall consider the history of the argument, explain the nuances various anti-evolution writers have brought to it, and offer thorough explanations for why the argument is fallacious. We shall emphasize in particular that the second law is best viewed as a mathematical statement. Since anti-evolutionists never make use of the mathematical structure of thermodynamics, invocations of the second law never contribute anything substantive to their discourse.

  11. Virus Evolution Serial

    SciTech Connect

    Vassilevska, Tanya

    2015-01-05

    This is the first code, designed to run on a desktop, which models the intracellular replication and the cell-to-cell infection and demonstrates virus evolution at the molecular level. This code simulates the infection of a population of "idealized biological cells" (represented as objects that do not divide or have metabolism) with "virus" (represented by its genetic sequence), the replication and simultaneous mutation of the virus which leads to evolution of the population of genetically diverse viruses. The code is built to simulate single-stranded RNA viruses. The input for the code is 1. the number of biological cells in the culture, 2. the initial composition of the virus population, 3. the reference genome of the RNA virus, 4. the coordinates of the genome regions and their significance and, 5. parameters determining the dynamics of virus replication, such as the mutation rate. The simulation ends when all cells have been infected or when no more infections occurs after a given number of attempts. The code has the ability to simulate the evolution of the virus in serial passage of cell "cultures", i.e. after the end of a simulation, a new one is immediately scheduled with a new culture of infected cells. The code outputs characteristics of the resulting virus population dynamics and genetic composition of the virus population, such as the top dominant genomes, percentage of a genome with specific characteristics.

  12. Thermodynamical Arguments Against Evolution

    NASA Astrophysics Data System (ADS)

    Rosenhouse, Jason

    2017-02-01

    The argument that the second law of thermodynamics contradicts the theory of evolution has recently been revived by anti-evolutionists. In its basic form, the argument asserts that whereas evolution implies that there has been an increase in biological complexity over time, the second law, a fundamental principle of physics, shows this to be impossible. Scientists have responded primarily by noting that the second law does not rule out increases in complexity in open systems, and since the Earth receives energy from the Sun, it is an open system. This reply is correct as far as it goes, and it adequately rebuts the most crude versions of the second law argument. However, it is insufficient against more sophisticated versions, and it leaves many relevant aspects of thermodynamics unexplained. We shall consider the history of the argument, explain the nuances various anti-evolution writers have brought to it, and offer thorough explanations for why the argument is fallacious. We shall emphasize in particular that the second law is best viewed as a mathematical statement. Since anti-evolutionists never make use of the mathematical structure of thermodynamics, invocations of the second law never contribute anything substantive to their discourse.

  13. Darwinian Evolution and Fractals

    NASA Astrophysics Data System (ADS)

    Carr, Paul H.

    2009-05-01

    Did nature's beauty emerge by chance or was it intelligently designed? Richard Dawkins asserts that evolution is blind aimless chance. Michael Behe believes, on the contrary, that the first cell was intelligently designed. The scientific evidence is that nature's creativity arises from the interplay between chance AND design (laws). Darwin's ``Origin of the Species,'' published 150 years ago in 1859, characterized evolution as the interplay between variations (symbolized by dice) and the natural selection law (design). This is evident in recent discoveries in DNA, Madelbrot's Fractal Geometry of Nature, and the success of the genetic design algorithm. Algorithms for generating fractals have the same interplay between randomness and law as evolution. Fractal statistics, which are not completely random, characterize such phenomena such as fluctuations in the stock market, the Nile River, rainfall, and tree rings. As chaos theorist Joseph Ford put it: God plays dice, but the dice are loaded. Thus Darwin, in discovering the evolutionary interplay between variations and natural selection, was throwing God's dice!

  14. Environment and Protostellar Evolution

    NASA Astrophysics Data System (ADS)

    Zhang, Yichen; Tan, Jonathan C.

    2015-04-01

    Even today in our Galaxy, stars form from gas cores in a variety of environments, which may affect the properties of the resulting star and planetary systems. Here, we study the role of pressure, parameterized via ambient clump mass surface density, on protostellar evolution and appearance, focusing on low-mass Sun-like stars and considering a range of conditions from relatively low pressure filaments in Taurus, to intermediate pressures of cluster-forming clumps like the Orion Nebula Cluster, to very high pressures that may be found in the densest infrared dark clouds or in the Galactic center. We present unified analytic and numerical models for the collapse of prestellar cores, accretion disks, protostellar evolution, and bipolar outflows, coupled with radiative transfer calculations and a simple astrochemical model to predict CO gas-phase abundances. Prestellar cores in high-pressure environments are smaller and denser and thus collapse with higher accretion rates and efficiencies, resulting in higher luminosity protostars with more powerful outflows. The protostellar envelope is heated to warmer temperatures, affecting infrared morphologies (and thus classification) and astrochemical processes like CO depletion onto dust grain ice mantles (and thus CO morphologies). These results have general implications for star and planet formation, especially via their effect on astrochemical and dust grain evolution during infall to and through protostellar accretion disks.

  15. Evolution of Metabolic Dependency

    NASA Astrophysics Data System (ADS)

    Shou, Wenying

    Microbes are often found to have lost their ability to make essential metabolites (auxotrophs) and instead rely on other individuals for these metabolites. How might metabolic dependency evolve to be so common? When microbes live inside a host (endosymbionts), amply host metabolites support auxotrophic endosymbionts. If the host transmits only a small number of endosymbionts to its offspring, then auxotrophic endosymbionts can rise to high frequency simply by chance. On the other hand, auxotrophs have also been observed in abundant free-living bacteria found in ocean water where nutrient supply is low. How might auxotrophs rise to an appreciable frequency in a large population when nutrient supply is low? We have found commonly-encountered conditions that facilitate the evolution of metabolic dependency. Metabolic interactions can in turn shape spatial organization of microbial communities (Momeni et al. (2013) eLife 2, 00230; Momeni et al. (2013) eLife 2, 00960; Estrela and Brown (2013) PLoS Comput Biol 9, e1003398; Muller et al. (2014) PNAS 111, 1037-1042). Rapid evolution of metabolic dependency can contribute to the complexity of microbial communities. Evolution of metabolic dependency.

  16. The evolution within us

    PubMed Central

    Cobey, Sarah; Wilson, Patrick; Matsen, Frederick A.

    2015-01-01

    The B-cell immune response is a remarkable evolutionary system found in jawed vertebrates. B-cell receptors, the membrane-bound form of antibodies, are capable of evolving high affinity to almost any foreign protein. High germline diversity and rapid evolution upon encounter with antigen explain the general adaptability of B-cell populations, but the dynamics of repertoires are less well understood. These dynamics are scientifically and clinically important. After highlighting the remarkable characteristics of naive and experienced B-cell repertoires, especially biased usage of genes encoding the B-cell receptors, we contrast methods of sequence analysis and their attempts to explain patterns of B-cell evolution. These phylogenetic approaches are currently unlinked to explicit models of B-cell competition, which analyse repertoire evolution at the level of phenotype, the affinities and specificities to particular antigenic sites. The models, in turn, suggest how chance, infection history and other factors contribute to different patterns of immunodominance and protection between people. Challenges in rational vaccine design, specifically vaccines to induce broadly neutralizing antibodies to HIV, underscore critical gaps in our understanding of B cells' evolutionary and ecological dynamics. PMID:26194749

  17. Jupiter G Impact Evolution

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This mosaic of WFPC-2 images shows the evolution of the Shoemaker-Levy 9 G impact site on Jupiter. The images from lower left to upper right show: the impact plume at 07/18/94 07:38 UT (about 5 minutes after the impact); the fresh impact site at 07/18/94 at 09:19 UT (1.5 hours after impact); the impact site after evolution by the winds of Jupiter (left), along with the L impact (right), taken on 07/21/94 at 6:22 UT (3 days after the G impact and 1.3 days after the L impact); and further evolution of the G and L sites due to winds and an additional impact (S) in the G vicinity, taken on 07/23/94 at 08:08 UT (5 days after the G impact).

    This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

  18. Photon track evolution.

    PubMed

    Oliveira, A D

    2005-01-01

    Given the time scale of biological, biochemical, biophysical and physical effects in a radiation exposure of living tissue, the first physical stage can be considered to be independent of time. All the physical interactions caused by the incident photons happen at the same starting time. From this point of view it would seem that the evolution of photon tracks is not a relevant topic for analysis; however, if the photon track is considered as a sequence of several interactions, there are several steps until the total degradation of the energy of the primary photon. We can characterise the photon track structure by the probability p(E,j), that is, the probability that a photon with energy E suffers j secondary interactions. The aim of this work is to analyse the photon track structure by considering j as a step of the photon track evolution towards the total degradation of the photon energy. Low energy photons (<150 keV) are considered, with water phantoms and half-extended geometry. The photon track evolution concept is presented and compared with the energy deposition along the track and also with the spatial distribution of the several steps in the photon track.

  19. The evolution of teaching.

    PubMed

    Fogarty, L; Strimling, P; Laland, K N

    2011-10-01

    Teaching, alongside imitation, is widely thought to underlie the success of humanity by allowing high-fidelity transmission of information, skills, and technology between individuals, facilitating both cumulative knowledge gain and normative culture. Yet, it remains a mystery why teaching should be widespread in human societies but extremely rare in other animals. We explore the evolution of teaching using simple genetic models in which a single tutor transmits adaptive information to a related pupil at a cost. Teaching is expected to evolve where its costs are outweighed by the inclusive fitness benefits that result from the tutor's relatives being more likely to acquire the valuable information. We find that teaching is not favored where the pupil can easily acquire the information on its own, or through copying others, or for difficult to learn traits, where teachers typically do not possess the information to pass on to relatives. This leads to a narrow range of traits for which teaching would be efficacious, which helps to explain the rarity of teaching in nature, its unusual distribution, and its highly specific nature. Further models that allow for cumulative cultural knowledge gain suggest that teaching evolved in humans because cumulative culture renders otherwise difficult-to-acquire valuable information available to teach. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  20. Evolution of segmented strings

    NASA Astrophysics Data System (ADS)

    Gubser, Steven S.

    2016-11-01

    I explain how to evolve segmented strings in de Sitter and anti-de Sitter spaces of any dimension in terms of forward-directed null displacements. The evolution is described entirely in terms of discrete hops which do not require a continuum spacetime. Moreover, the evolution rule is purely algebraic, so it can be defined not only on ordinary real de Sitter and anti-de Sitter but also on the rational points of the quadratic equations that define these spaces. For three-dimensional anti-de Sitter space, a simpler evolution rule is possible that descends from the Wess-Zumino-Witten equations of motion. In this case, one may replace three-dimensional anti-de Sitter space by a noncompact discrete subgroup of S L (2 ,R ) whose structure is related to the Pell equation. A discrete version of the Bañados-Teitelboim-Zanelli (BTZ) black hole can be constructed as a quotient of this subgroup. This discrete black hole avoids the firewall paradox by a curious mechanism: even for large black holes, there are no points inside the horizon until one reaches the singularity.

  1. SNRPy: Supernova remnant evolution modeling

    NASA Astrophysics Data System (ADS)

    Leahy, Denis A.; Williams, Jacqueline

    2017-03-01

    SNRPy (Super Nova Remnant Python) models supernova remnant (SNR) evolution and is useful for understanding SNR evolution and to model observations of SNR for obtaining good estimates of SNR properties. It includes all phases for the standard path of evolution for spherically symmetric SNRs and includes alternate evolutionary models, including evolution in a cloudy ISM, the fractional energy loss model, and evolution in a hot low-density ISM. The graphical interface takes in various parameters and produces outputs such as shock radius and velocity vs. time, SNR surface brightness profile and spectrum.

  2. Group selection in behavioral evolution.

    PubMed

    Rachlin, Howard

    2017-09-09

    How may patterns of behavior change over an organism's lifetime? The answer is that they evolve (behavioral evolution) as species evolve over generations (biological evolution). In biological evolution, under certain conditions, groups of cooperative organisms would be selected over groups of non-cooperative organisms, even when cooperation imposes a cost to individuals. Analogously, in behavioral evolution, patterns of acts may be selected even when each individual act in the pattern is costly. Although there is considerable debate among biologists whether the conditions for group selection are met in biological evolution, it is argued here that they are met in behavioral evolution (as well as in cultural evolution). The article shows how selection of patterns can explain the learning of self-control and altruism. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Experimental Evolution with Caenorhabditis Nematodes

    PubMed Central

    Teotónio, Henrique; Estes, Suzanne; Phillips, Patrick C.; Baer, Charles F.

    2017-01-01

    The hermaphroditic nematode Caenorhabditis elegans has been one of the primary model systems in biology since the 1970s, but only within the last two decades has this nematode also become a useful model for experimental evolution. Here, we outline the goals and major foci of experimental evolution with C. elegans and related species, such as C. briggsae and C. remanei, by discussing the principles of experimental design, and highlighting the strengths and limitations of Caenorhabditis as model systems. We then review three exemplars of Caenorhabditis experimental evolution studies, underlining representative evolution experiments that have addressed the: (1) maintenance of genetic variation; (2) role of natural selection during transitions from outcrossing to selfing, as well as the maintenance of mixed breeding modes during evolution; and (3) evolution of phenotypic plasticity and its role in adaptation to variable environments, including host–pathogen coevolution. We conclude by suggesting some future directions for which experimental evolution with Caenorhabditis would be particularly informative. PMID:28592504

  4. Apport de la simulation numérique à la compréhension des mécanismes d'interaction de cavités dans le cadre de la modélisation de l'endommagement ductile sous sollicitation dynamique

    NASA Astrophysics Data System (ADS)

    Roy, G.; Buy, F.; Llorca, F.

    2002-12-01

    L'étude présentée s'inscrit dans le cadre d'une démarche menant à la construction d'un modèle analytique ou semi analytique de comportement élasto-visco-plastique endommageable, applicable aux chargements rencontrés en configuration d'impact violent et générant de l'écaillage ductile. La prise en compte des effets de compressibilité et de micro inertie est essentielle pour modéliser la phase de croissance. Des simulations numériques globales de la structure et locales à l'échelle des hétérogénéités permettent d'évaluer les niveaux de sollicitations dans les zones susceptibles de s'endommager, dévaluer des critères analytiques de germination de l'endommagement et de comprendre les mécanismes d'interaction entre les défauts. Les effets micro inertiels et de compressibilité sont ainsi mis en évidence dans les phases de germination et de coalescence des micro défauts. II s'agit ici d'une illustration non exhaustive de travaux engagés au CEA Valduc sur le tantale, dans le cadre d'une thèse [10]. Un programme matériaux en partenariat CEA-CNRS sur la modélisation multi échelles du comportement de structures a également été initié dans ce contexte.

  5. Evolution of Sedimentary Rocks

    NASA Astrophysics Data System (ADS)

    Veizer, J.; MacKenzie, F. T.

    2003-12-01

    For almost a century, it has been recognized that the present-day thickness and areal extent of Phanerozoic sedimentary strata increase progressively with decreasing geologic age. This pattern has been interpreted either as reflecting an increase in the rate of sedimentation toward the present (Barrell, 1917; Schuchert, 1931; Ronov, 1976) or as resulting from better preservation of the younger part of the geologic record ( Gilluly, 1949; Gregor, 1968; Garrels and Mackenzie, 1971a; Veizer and Jansen, 1979, 1985).Study of the rocks themselves led to similarly opposing conclusions. The observed secular (=age) variations in relative proportions of lithological types and in chemistry of sedimentary rocks (Daly, 1909; Vinogradov et al., 1952; Nanz, 1953; Engel, 1963; Strakhov, 1964, 1969; Ronov, 1964, 1982) were mostly given an evolutionary interpretation. An opposing, uniformitarian, approach was proposed by Garrels and Mackenzie (1971a). For most isotopes, the consensus favors deviations from the present-day steady state as the likely cause of secular trends.This chapter attempts to show that recycling and evolution are not opposing, but complementary, concepts. It will concentrate on the lithological and chemical attributes of sediments, but not deal with the evolution of sedimentary mineral deposits (Veizer et al., 1989) and of life ( Sepkoski, 1989), both well amenable to the outlined conceptual treatment. The chapter relies heavily on Veizer (1988a) for the sections dealing with general recycling concepts, on Veizer (2003) for the discussion of isotopic evolution of seawater, and on Morse and Mackenzie (1990) and Mackenzie and Morse (1992) for discussion of carbonate rock recycling and environmental attributes.

  6. Dynamics of secular evolution

    NASA Astrophysics Data System (ADS)

    Binney, James

    2013-10-01

    The material in this article was presented in five hours of lectures to the 2011 Canary Islands Winter School. The School’s theme was ‘Secular Evolution of Galaxies’ and my task was to present the underlying stellar-dynamical theory. Other lecturers were speaking on the role of bars and chemical evolution, so these topics are avoided here. The material starts with an account of the connections between isolating integrals, quasiperiodicity and angle-action variables - these variables played a prominent and unifying role throughout the lectures. This leads on to the phenomenon of resonant trap- ping and how this can lead to chaos in cuspy potentials and phase-space mixing in slowly evolving potentials. Surfaces of section and frequency analysis are introduced as diagnostics of phase-space structure. Real galactic potentials include a fluctuating part that drives the system towards unattainable thermal equilibrium. Two-body encounters are only one source of fluctuations, and all fluctuations will drive similar evolution. The orbit-averaged Fokker-Planck equation is derived, as are relations that hold between the second-order diffusion coefficients and both the power spectrum of the fluctuations and the first-order diffusion coefficients. From the observed heating of the solar neighbourhood we show that the second-order diffusion coefficients must scale as ˜ J1/2. We show that periodic spiral structure shifts angular momentum outwards, heating at the Lindblad resonances and mixing at corotation. The equation that would yield the normal modes of a stellar disk is first derived and then used to discuss the propagation of tightly wound spiral waves. The winding up of such waves is described and explains why cool stellar disks are responsive systems that amplify ambient noise. An explanation is offered of why the Lin-Shu-Kalnajs dispersion relation and even global normal-mode calculations provide a very incomplete understanding of the dynamics of stellar disks.

  7. Evolution before genes

    PubMed Central

    2012-01-01

    Background Our current understanding of evolution is so tightly linked to template-dependent replication of DNA and RNA molecules that the old idea from Oparin of a self-reproducing 'garbage bag' ('coacervate') of chemicals that predated fully-fledged cell-like entities seems to be farfetched to most scientists today. However, this is exactly the kind of scheme we propose for how Darwinian evolution could have occurred prior to template replication. Results We cannot confirm previous claims that autocatalytic sets of organic polymer molecules could undergo evolution in any interesting sense by themselves. While we and others have previously imagined inhibition would result in selectability, we found that it produced multiple attractors in an autocatalytic set that cannot be selected for. Instead, we discovered that if general conditions are satisfied, the accumulation of adaptations in chemical reaction networks can occur. These conditions are the existence of rare reactions producing viable cores (analogous to a genotype), that sustains a molecular periphery (analogous to a phenotype). Conclusions We conclude that only when a chemical reaction network consists of many such viable cores, can it be evolvable. When many cores are enclosed in a compartment there is competition between cores within the same compartment, and when there are many compartments, there is between-compartment competition due to the phenotypic effects of cores and their periphery at the compartment level. Acquisition of cores by rare chemical events, and loss of cores at division, allows macromutation, limited heredity and selectability, thus explaining how a poor man's natural selection could have operated prior to genetic templates. This is the only demonstration to date of a mechanism by which pre-template accumulation of adaptation could occur. Reviewers This article was reviewed by William Martin and Eugene Koonin. PMID:22221860

  8. Next generation PON evolution

    NASA Astrophysics Data System (ADS)

    Srivastava, Anand

    2013-01-01

    Passive optical network (PON) features a point-to-multi-point (P2MP) architecture to provide broadband access. The P2MP architecture has become the most popular solution for FTTx deployment among operators. PON-based FTTx has been widely deployed ever since 2004 when ITU-T Study Group 15Q2 completed recommendations that defined GPON system [ITU-T seriesG.984]. As full services are provisioned by the massive deployment of PON networks worldwide, operators expect more from PONs. These include improved bandwidths and service support capabilities as well as enhanced performance of access nodes and supportive equipment over their existing PON networks. The direction of PON evolution is a key issue for the telecom industry. Full Service Access Network (FSAN) and ITU-T are the PON interest group and standard organization, respectively. In their view, the next-generation PONs are divided into two phases: NG-PON1 and NG-PON2. Mid-term upgrades in PON networks are defined as NG-PON1, while NG-PON2 is a long-term solution in PON evolution. Major requirements of NG-PON1 are the coexistence with the deployed GPON systems and the reuse of outside plant. Optical Distribution Networks (ODNs) account for 70% of the total investments in deploying PONs. Therefore, it is crucial for the NGPON evolution to be compatible with the deployed networks. With the specification of system coexistence and ODN reuse, the only hold-up of the migration from GPON to NG-PON1 is the maturity of the industry chain. Unlike NG-PON1 that has clear goals and emerging developments, there are many candidate technologies for NG-PON2. The selection of NG-PON2 is under discussion. However, one thing is clear, NG-PON2 technology must outperform NG-PON1 technologies in terms of ODN compatibility, bandwidth, capacity, and cost-efficiency.

  9. Collisional Evolution of Planetesimals

    NASA Astrophysics Data System (ADS)

    Leinhardt, Zoë Malka

    2010-05-01

    Over 400 extrasolar planets have been discovered. These planetary systems are very different from our solar system and surprisingly diverse. The large number of planets detected suggests that planet formation is common around main sequence stars. The major problem facing the scientific community with regards to these discoveries is that observations cannot trace the history of planet formation. Observations provide snapshots of the early stages of a protoplanetary gas disk orbiting a young star and the late stages after planetary systems have formed. But the evolution from a young star to a planetary system has not been observed. Thus, the challenge is to connect the early and late stages of planet formation. Planets form from the collisional growth of planetary building blocks, planetesimals. In recent numerical work we found that the resistance of planetesimals to collisional erosion changes dramatically during planet formation. Young planetesimals are weak aggregates that are easily disrupted due to efficient momentum coupling during low-velocity collisions in early phases of collisional evolution. However, as impact speeds increase the same weak planetesimals become dramatically stronger because the shock from a supersonic impact loses energy to deformation and phase changes. Our work identifies a paradox for the early stages of planet formation. Objects in the km-size range are weak and susceptible to collisional disruption. However, this disruption may actually produce large amounts of debris that can be accreted by remaining undisrupted planetesimals allowing growth. As we work to disentangle these sorts of conundrums we can expect to put forward hypotheses for collisional remnants in our solar system - for example, the dwarf planet Haumea and its collisional family. In this talk I will review the current understanding of planetesimal evolution and discuss how future numerical simulations may connect observational snapshots to provide a complete history of

  10. Evolution and human sexuality.

    PubMed

    Gray, Peter B

    2013-12-01

    The aim of this review is to put core features of human sexuality in an evolutionary light. Toward that end, I address five topics concerning the evolution of human sexuality. First, I address theoretical foundations, including recent critiques and developments. While much traces back to Darwin and his view of sexual selection, more recent work helps refine the theoretical bases to sex differences and life history allocations to mating effort. Second, I consider central models attempting to specify the phylogenetic details regarding how hominin sexuality might have changed, with most of those models honing in on transitions from a possible chimpanzee-like ancestor to the slightly polygynous and long-term bonded sociosexual partnerships observed among most recently studied hunter-gatherers. Third, I address recent genetic and physiological data contributing to a refined understanding of human sexuality. As examples, the availability of rapidly increasing genomic information aids comparative approaches to discern signals of selection in sexuality-related phenotypes, and neuroendocrine studies of human responses to sexual stimuli provide insight into homologous and derived mechanisms. Fourth, I consider some of the most recent, large, and rigorous studies of human sexuality. These provide insights into sexual behavior across other national samples and on the Internet. Fifth, I discuss the relevance of a life course perspective to understanding the evolution of human sexuality. Most research on the evolution of human sexuality focuses on young adults. Yet humans are sexual beings from gestation to death, albeit in different ways across the life course, and in ways that can be theoretically couched within life history theory. Copyright © 2013 Wiley Periodicals, Inc.

  11. Evolution before genes.

    PubMed

    Vasas, Vera; Fernando, Chrisantha; Santos, Mauro; Kauffman, Stuart; Szathmáry, Eörs

    2012-01-05

    Our current understanding of evolution is so tightly linked to template-dependent replication of DNA and RNA molecules that the old idea from Oparin of a self-reproducing 'garbage bag' ('coacervate') of chemicals that predated fully-fledged cell-like entities seems to be farfetched to most scientists today. However, this is exactly the kind of scheme we propose for how Darwinian evolution could have occurred prior to template replication. We cannot confirm previous claims that autocatalytic sets of organic polymer molecules could undergo evolution in any interesting sense by themselves. While we and others have previously imagined inhibition would result in selectability, we found that it produced multiple attractors in an autocatalytic set that cannot be selected for. Instead, we discovered that if general conditions are satisfied, the accumulation of adaptations in chemical reaction networks can occur. These conditions are the existence of rare reactions producing viable cores (analogous to a genotype), that sustains a molecular periphery (analogous to a phenotype). We conclude that only when a chemical reaction network consists of many such viable cores, can it be evolvable. When many cores are enclosed in a compartment there is competition between cores within the same compartment, and when there are many compartments, there is between-compartment competition due to the phenotypic effects of cores and their periphery at the compartment level. Acquisition of cores by rare chemical events, and loss of cores at division, allows macromutation, limited heredity and selectability, thus explaining how a poor man's natural selection could have operated prior to genetic templates. This is the only demonstration to date of a mechanism by which pre-template accumulation of adaptation could occur.

  12. Evolution was chemically constrained.

    PubMed

    Williams, R J P; Fraústo Da Silva, J J R

    2003-02-07

    The objective of this paper is to present a systems view of the major features of biological evolution based upon changes in internal chemistry and uses of cellular space, both of which it will be stated were dependent on the changing chemical environment. The account concerns the major developments from prokaryotes to eukaryotes, to multi-cellular organisms, to animals with nervous systems and a brain, and finally to human beings and their uses of chemical elements in space outside themselves. It will be stated that the changes were in an inevitable progression, and were not just due to blind chance, so that "random searching" by a coded system to give species had a fixed overall route. The chemical sequence is from a reducing to an ever-increasingly oxidizing environment, while organisms retained reduced chemicals. The process was furthered recently by human beings who have also increased the range of reduced products trapped on Earth in novel forms. All the developments are brought about from the nature of the chemicals which organisms accumulate using the environment and its changes. The relationship to the manner in which particular species (gene sequences) were coincidentally changed, the molecular view of evolution, is left for additional examination. There is a further issue in that the changes of the chemistry of the environment developed largely at equilibrium due to the relatively fast reactions there of the available inorganic chemicals. Inside cells, some of these same chemicals also came to equilibrium within compounds. All such equilibria reduced the variance (degrees of freedom) of the total environmental/biological system and its possible development. However, the more sophisticated organic chemistry, almost totally inside cells until humans evolved, is kinetically controlled and limited by the demands of cellular reduction necessary to produce essential chemicals and by the availability of certain elements and energy. Hence the variability of

  13. Evolution of Atmospheres

    SciTech Connect

    Hanson, B.

    1993-02-12

    An atmosphere is the dynamic gaseous boundary layer between a planet and space. Many complex interactions affect the composition and time evolution of an atmosphere and control the environment - or climate - at a planet's surface. These include both reactions within the atmosphere as well as exchange of energy, gases, and dust with the planet below and the solar system above; for Earth today, interactions with the biosphere and oceans are paramount. In view of the large changes in inputs of energy and gases that have occurred since planets began to form and the complexity of the chemistry, it is not surprising that planetary climates have changed greatly and are continuing to change.

  14. Demonstrating Supernova Remnant Evolution

    NASA Astrophysics Data System (ADS)

    Leahy, Denis A.; Williams, Jacqueline

    2017-01-01

    We have created a software tool to calculate at display supernova remnant evolution which includes all stages from early ejecta dominated phase to late-time merging with the interstellar medium. The software was created using Python, and can be distributed as Python code, or as an executable file. The purpose of the software is to demonstrate the different phases and transitions that a supernova remnant undergoes, and will be used in upper level undergraduate astrophysics courses as a teaching tool. The usage of the software and its graphical user interface will be demonstrated.

  15. [Evolution of dissociative learning].

    PubMed

    Azarashvili, A A

    2010-01-01

    This review considers data obtained during the entire research period of state-dependent learning. Understanding of this phenomenon has significantly evolved during the past decades, as a result of the increasing amount of facts revealed while studying state-dependent learning. Consequently, a situation has arisen where different papers may describe same phenomena using different terms. This does not promote understanding of the described phenomena. Therefore a need for a paper emerged, that would analyze the evolution of state-dependent learning and would offer terminology corresponding to all the data collected on the subject.

  16. Evolution of enzyme superfamilies.

    PubMed

    Glasner, Margaret E; Gerlt, John A; Babbitt, Patricia C

    2006-10-01

    Enzyme evolution is often constrained by aspects of catalysis. Sets of homologous proteins that catalyze different overall reactions but share an aspect of catalysis, such as a common partial reaction, are called mechanistically diverse superfamilies. The common mechanistic steps and structural characteristics of several of these superfamilies, including the enolase, Nudix, amidohydrolase, and haloacid dehalogenase superfamilies have been characterized. In addition, studies of mechanistically diverse superfamilies are helping to elucidate mechanisms of functional diversification, such as catalytic promiscuity. Understanding how enzyme superfamilies evolve is vital for accurate genome annotation, predicting protein functions, and protein engineering.

  17. Is evolution finished?

    PubMed

    Davison, John A

    2004-01-01

    Since speciation seems to be no longer in progress, one is compelled to conclude that sexual reproduction is incompetent as a macroevolutionary device. I propose that the reason some might insist that evolution is still in progress stems primarily from the influence of two authorities, the geologist Charles Lyell, with his doctrine of uniformitarianism and Gregor Mendel, the discoverer of sexually mediated transmission genetics. William Bateson, the father of modern genetics, clearly foresaw the failure of Mendelism to explain macroevolutionary change, a perspective with which I am in full agreement.

  18. Chromosomal evolution in Rodentia

    PubMed Central

    Romanenko, S A; Perelman, P L; Trifonov, V A; Graphodatsky, A S

    2012-01-01

    Rodentia is the most species-rich mammalian order and includes several important laboratory model species. The amount of new information on karyotypic and phylogenetic relations within and among rodent taxa is rapidly increasing, but a synthesis of these data is currently lacking. Here, we have integrated information drawn from conventional banding studies, recent comparative painting investigations and molecular phylogenetic reconstructions of different rodent taxa. This permitted a revision of several ancestral karyotypic reconstructions, and a more accurate depiction of rodent chromosomal evolution. PMID:22086076

  19. The evolution of nucleotides

    NASA Technical Reports Server (NTRS)

    Usher, D. A.; Needels, M. C.

    1986-01-01

    Examples of chiral selection in nonenzymatic aminoacylation of internal 2-prime hydroxyl groups of oligo- and polynucleotides are discussed as an evidence for the early evolution of bionucleotides. Some factors that could influence the degree of this chiral selection and its direction are discussed. These include the structure of the aminoacyl component, the structure of the nucleoside component, and the reaction conditions. Investigation of the mechanism of this reaction was aided by the use of 3-prime inosine methyl phosphate (as a simplified model for a dinucleoside monophosphate) and proton NMR spectroscopy of t-butoxycarbonyl-alanyl esters of nucleosides as models for the transition state of the aminoacylation reaction itself.

  20. Evolution of Trading strategies

    NASA Astrophysics Data System (ADS)

    Vicente, Javier

    2007-03-01

    We attempt to classify the trading strategies of agents in the London Stock Exchange into broad categories. Our study is based on that that identifies the member of the exchange associated with each transaction. Based on the evolution of the inventory (holdings of the stock) as a function of time, we use clustering methods to classify the strategies into several groups. We study how these groups evolve in time and attempt to correlate the membership of the groups with other market properties, such as price volatility.

  1. Student Visual Communication of Evolution

    NASA Astrophysics Data System (ADS)

    Oliveira, Alandeom W.; Cook, Kristin

    2016-05-01

    Despite growing recognition of the importance of visual representations to science education, previous research has given attention mostly to verbal modalities of evolution instruction. Visual aspects of classroom learning of evolution are yet to be systematically examined by science educators. The present study attends to this issue by exploring the types of evolutionary imagery deployed by secondary students. Our visual design analysis revealed that students resorted to two larger categories of images when visually communicating evolution: spatial metaphors (images that provided a spatio-temporal account of human evolution as a metaphorical "walk" across time and space) and symbolic representations ("icons of evolution" such as personal portraits of Charles Darwin that simply evoked evolutionary theory rather than metaphorically conveying its conceptual contents). It is argued that students need opportunities to collaboratively critique evolutionary imagery and to extend their visual perception of evolution beyond dominant images.

  2. Evolution across the Curriculum: Microbiology

    PubMed Central

    Burmeister, Alita R.; Smith, James J.

    2016-01-01

    An integrated understanding of microbiology and evolutionary biology is essential for students pursuing careers in microbiology and healthcare fields. In this Perspective, we discuss the usefulness of evolutionary concepts and an overall evolutionary framework for students enrolled in microbiology courses. Further, we propose a set of learning goals for students studying microbial evolution concepts. We then describe some barriers to microbial evolution teaching and learning and encourage the continued incorporation of evidence-based teaching practices into microbiology courses at all levels. Next, we review the current status of microbial evolution assessment tools and describe some education resources available for teaching microbial evolution. Successful microbial evolution education will require that evolution be taught across the undergraduate biology curriculum, with a continued focus on applications and applied careers, while aligning with national biology education reform initiatives. Journal of Microbiology & Biology Education PMID:27158306

  3. Plant domestication slows pest evolution.

    PubMed

    Turcotte, Martin M; Lochab, Amaneet K; Turley, Nash E; Johnson, Marc T J

    2015-09-01

    Agricultural practices such as breeding resistant varieties and pesticide use can cause rapid evolution of pest species, but it remains unknown how plant domestication itself impacts pest contemporary evolution. Using experimental evolution on a comparative phylogenetic scale, we compared the evolutionary dynamics of a globally important economic pest - the green peach aphid (Myzus persicae) - growing on 34 plant taxa, represented by 17 crop species and their wild relatives. Domestication slowed aphid evolution by 13.5%, maintained 10.4% greater aphid genotypic diversity and 5.6% higher genotypic richness. The direction of evolution (i.e. which genotypes increased in frequency) differed among independent domestication events but was correlated with specific plant traits. Individual-based simulation models suggested that domestication affects aphid evolution directly by reducing the strength of selection and indirectly by increasing aphid density and thus weakening genetic drift. Our results suggest that phenotypic changes during domestication can alter pest evolutionary dynamics.

  4. Student Visual Communication of Evolution

    NASA Astrophysics Data System (ADS)

    Oliveira, Alandeom W.; Cook, Kristin

    2017-06-01

    Despite growing recognition of the importance of visual representations to science education, previous research has given attention mostly to verbal modalities of evolution instruction. Visual aspects of classroom learning of evolution are yet to be systematically examined by science educators. The present study attends to this issue by exploring the types of evolutionary imagery deployed by secondary students. Our visual design analysis revealed that students resorted to two larger categories of images when visually communicating evolution: spatial metaphors (images that provided a spatio-temporal account of human evolution as a metaphorical "walk" across time and space) and symbolic representations ("icons of evolution" such as personal portraits of Charles Darwin that simply evoked evolutionary theory rather than metaphorically conveying its conceptual contents). It is argued that students need opportunities to collaboratively critique evolutionary imagery and to extend their visual perception of evolution beyond dominant images.

  5. Evolution of fetal ultrasonography.

    PubMed

    Avni, F E; Cos, T; Cassart, M; Massez, A; Donner, C; Ismaili, K; Hall, M

    2007-02-01

    The authors wish to highlight the evolution that has occurred in fetal ultrasound in recent years. A first significant evolution lies in the increasing contribution of first trimester ultrasound for the detection of fetal anomalies. Malformations of several organs and systems have been diagnosed during the first trimester. Furthermore the systematic measurement of the fetal neck translucency has led to increasing rate of detection of aneuploidies and heart malformations. For several years now, three-dimensional (3D) and 4D ultrasound (US) have been used as a complementary tool to 2D US for the evaluation of fetal morphology. This brings an improved morphologic assessment of the fetus. Applications of the techniques are increasing, especially for the fetal face, heart and extremities. The third field where fetal US is continuously providing important information is the knowledge of the natural history of diseases. This has brought significant improvement in the postnatal management of several diseases, especially urinary tract dilatation and broncho-pulmonary malformation.

  6. Hox genes and evolution.

    PubMed

    Hrycaj, Steven M; Wellik, Deneen M

    2016-01-01

    Hox proteins are a deeply conserved group of transcription factors originally defined for their critical roles in governing segmental identity along the antero-posterior (AP) axis in Drosophila. Over the last 30 years, numerous data generated in evolutionarily diverse taxa have clearly shown that changes in the expression patterns of these genes are closely associated with the regionalization of the AP axis, suggesting that Hox genes have played a critical role in the evolution of novel body plans within Bilateria. Despite this deep functional conservation and the importance of these genes in AP patterning, key questions remain regarding many aspects of Hox biology. In this commentary, we highlight recent reports that have provided novel insight into the origins of the mammalian Hox cluster, the role of Hox genes in the generation of a limbless body plan, and a novel putative mechanism in which Hox genes may encode specificity along the AP axis. Although the data discussed here offer a fresh perspective, it is clear that there is still much to learn about Hox biology and the roles it has played in the evolution of the Bilaterian body plan.

  7. Geometry Genetics and Evolution

    NASA Astrophysics Data System (ADS)

    Siggia, Eric

    2011-03-01

    Darwin argued that highly perfected organs such as the vertebrate eye could evolve by a series of small changes, each of which conferred a selective advantage. In the context of gene networks, this idea can be recast into a predictive algorithm, namely find networks that can be built by incremental adaptation (gradient search) to perform some task. It embodies a ``kinetic'' view of evolution where a solution that is quick to evolve is preferred over a global optimum. Examples of biochemical kinetic networks were evolved for temporal adaptation, temperature compensated entrainable clocks, explore-exploit trade off in signal discrimination, will be presented as well as networks that model the spatially periodic somites (vertebrae) and HOX gene expression in the vertebrate embryo. These models appear complex by the criterion of 19th century applied mathematics since there is no separation of time or spatial scales, yet they are all derivable by gradient optimization of simple functions (several in the Pareto evolution) often based on the Shannon entropy of the time or spatial response. Joint work with P. Francois, Physics Dept. McGill University. With P. Francois, Physics Dept. McGill University

  8. Heat freezes niche evolution.

    PubMed

    Araújo, Miguel B; Ferri-Yáñez, Francisco; Bozinovic, Francisco; Marquet, Pablo A; Valladares, Fernando; Chown, Steven L

    2013-09-01

    Climate change is altering phenology and distributions of many species and further changes are projected. Can species physiologically adapt to climate warming? We analyse thermal tolerances of a large number of terrestrial ectotherm (n = 697), endotherm (n = 227) and plant (n = 1816) species worldwide, and show that tolerance to heat is largely conserved across lineages, while tolerance to cold varies between and within species. This pattern, previously documented for ectotherms, is apparent for this group and for endotherms and plants, challenging the longstanding view that physiological tolerances of species change continuously across climatic gradients. An alternative view is proposed in which the thermal component of climatic niches would overlap across species more than expected. We argue that hard physiological boundaries exist that constrain evolution of tolerances of terrestrial organisms to high temperatures. In contrast, evolution of tolerances to cold should be more frequent. One consequence of conservatism of upper thermal tolerances is that estimated niches for cold-adapted species will tend to underestimate their upper thermal limits, thereby potentially inflating assessments of risk from climate change. In contrast, species whose climatic preferences are close to their upper thermal limits will unlikely evolve physiological tolerances to increased heat, thereby being predictably more affected by warming.

  9. Evolution in thermodynamics

    NASA Astrophysics Data System (ADS)

    Bejan, Adrian

    2017-03-01

    This review covers two aspects of "evolution" in thermodynamics. First, with the constructal law, thermodynamics is becoming the domain of physics that accounts for the phenomenon of evolution in nature, in general. Second, thermodynamics (and science generally) is the evolving add-on that empowers humans to predict the future and move more easily on earth, farther and longer in time. The part of nature that thermodynamics represents is this: nothing moves by itself unless it is driven by power, which is then destroyed (dissipated) during movement. Nothing evolves unless it flows and has the freedom to change its architecture such that it provides greater and easier access to the available space. Thermodynamics is the modern science of heat and work and their usefulness, which comes from converting the work (power) into movement (life) in flow architectures that evolve over time to facilitate movement. I also review the rich history of the science, and I clarify misconceptions regarding the second law, entropy, disorder, and the arrow of time, and the supposed analogy between heat and work.

  10. Intron evolution in Saccharomycetaceae.

    PubMed

    Hooks, Katarzyna B; Delneri, Daniela; Griffiths-Jones, Sam

    2014-09-01

    Introns in protein-coding genes are very rare in hemiascomycetous yeast genomes. It has been suggested that these species have experienced extensive intron loss during their evolution from the postulated intron-rich fungal ancestor. However, no intron-devoidy east species have been identified and some of the introns remaining within the genomes of intron-poor species, such as Saccharomyces cerevisiae, appear to be beneficial during growth under stress conditions. In order to reveal the pattern of intron retention within intron-poor yeast species and better understand the mechanisms of intron evolution, we generated a comprehensive set of 250 orthologous introns in the 20 species that comprise the Saccharomycetaceae, by analyzing RNA deep-sequencing data and alignments of intron-containing genes. Analysis of these intron sets shows that intron loss is at least two orders of magnitude more frequent than intron gain. Fine mapping of intron positions shows that intron sliding is rare, and that introns are almost always removed without changing the primary sequence of the encoded protein. The latter finding is consistent with the prevailing view that homologous recombination between reverse-transcribed mature mRNAs and the corresponding genomic locus is the primary mechanism of intron loss. However, we also find evidence that loss of a small number of introns is mediated by micro-homology, and that the number of intron losses is diminished in yeast species that have lost the microhomology end joining and nonhomologous end joining machinery.

  11. Evolution of the tapetum.

    PubMed

    Schwab, Ivan R; Yuen, Carlton K; Buyukmihci, Nedim C; Blankenship, Thomas N; Fitzgerald, Paul G

    2002-01-01

    To review, contrast, and compare current known tapetal mechanisms and review the implications for the evolution of the tapetum. Ocular specimens of representative fish in key piscine families, including Acipenseridae, Cyprinidae, Chacidae; the reptilian family Crocodylidae; the mammalian family Felidae; and the Lepidopteran family Sphingidae were reviewed and compared histologically. All known varieties of tapeta were examined and classified and compared to the known cladogram representing the evolution of each specific family. Types of tapeta include tapetum cellulosum, tapetum fibrosum, retinal tapetum, invertebrate pigmented tapetum, and invertebrate thin-film tapetum. All but the invertebrate pigmented tapetum were examined histologically. Review of the evolutionary cladogram and comparison with known tapeta suggest that the tapetum evolved in the Devonian period 345 to 395 million years ago. Tapeta developed independently in at least three separate orders in invertebrates and vertebrates, and yet all have surprisingly similar mechanisms of light reflection, including thin-film interference, diffusely reflecting tapeta, Mie scattering, Rayleigh scattering, and perhaps orthogonal retroreflection. Tapeta are found in invertebrates and vertebrates and display different physical mechanisms of reflection. Each tapetum reflects the wavelengths most relevant to the species' ecological niche. With this work, we have hypothesized that the tapetum evolved independently in both invertebrates and vertebrates as early as the Devonian period and coincided with an explosion of life forms.

  12. Modeling Protein Evolution

    NASA Astrophysics Data System (ADS)

    Goldstein, Richard; Pollock, David

    The study of biology is fundamentally different from many other scientific pursuits, such as geology or astrophysics. This difference stems from the ubiquitous questions that arise about function and purpose. These are questions concerning why biological objects operate the way they do: what is the function of a polymerase? What is the role of the immune system? No one, aside from the most dedicated anthropist or interventionist theist, would attempt to determine the purpose of the earth's mantle or the function of a binary star. Among the sciences, it is only biology in which the details of what an object does can be said to be part of the reason for its existence. This is because the process of evolution is capable of improving an object to better carry out a function; that is, it adapts an object within the constraints of mechanics and history (i.e., what has come before). Thus, the ultimate basis of these biological questions is the process of evolution; generally, the function of an enzyme, cell type, organ, system, or trait is the thing that it does that contributes to the fitness (i.e., reproductive success) of the organism of which it is a part or characteristic. Our investigations cannot escape the simple fact that all things in biology (including ourselves) are, ultimately, the result of an evolutionary process.

  13. Evolution of morphological allometry.

    PubMed

    Pélabon, Christophe; Firmat, Cyril; Bolstad, Geir H; Voje, Kjetil L; Houle, David; Cassara, Jason; Rouzic, Arnaud Le; Hansen, Thomas F

    2014-07-01

    Morphological allometry refers to patterns of covariance between body parts resulting from variation in body size. Whether measured during growth (ontogenetic allometry), among individuals at similar developmental stage (static allometry), or among populations or species (evolutionary allometry), allometric relationships are often tight and relatively invariant. Consequently, it has been suggested that allometries have low evolvability and could constrain phenotypic evolution by forcing evolving species along fixed trajectories. Alternatively, allometric relationships may result from natural selection for functional optimization. Despite nearly a century of active research, distinguishing between these alternatives remains difficult, partly due to wide differences in the meaning assigned to the term allometry. In particular, a broad use of the term, encompassing any monotonic relationship between body parts, has become common. This usage breaks the connection to the proportional growth regulation that motivated Huxley's original narrow-sense use of allometry to refer to power-law relationships between traits. Focusing on the narrow-sense definition of allometry, we review here evidence for and against the allometry-as-a-constraint hypothesis. Although the low evolvability and the evolutionary invariance of the static allometric slope observed in some studies suggest a possible constraining effect of this parameter on phenotypic evolution, the lack of knowledge about selection on allometry prevents firm conclusions. © 2014 New York Academy of Sciences.

  14. Evolution of Oxygenic Photosynthesis

    NASA Astrophysics Data System (ADS)

    Fischer, Woodward W.; Hemp, James; Johnson, Jena E.

    2016-06-01

    The origin of oxygenic photosynthesis was the most important metabolic innovation in Earth history. It allowed life to generate energy and reducing power directly from sunlight and water, freeing it from the limited resources of geochemically derived reductants. This greatly increased global primary productivity and restructured ecosystems. The release of O2 as an end product of water oxidation led to the rise of oxygen, which dramatically altered the redox state of Earth's atmosphere and oceans and permanently changed all major biogeochemical cycles. Furthermore, the biological availability of O2 allowed for the evolution of aerobic respiration and novel biosynthetic pathways, facilitating much of the richness we associate with modern biology, including complex multicellularity. Here we critically review and synthesize information from the geological and biological records for the origin and evolution of oxygenic photosynthesis. Data from both of these archives illustrate that this metabolism first appeared in early Paleoproterozoic time and, despite its biogeochemical prominence, is a relatively late invention in the context of our planet's history.

  15. Intron Evolution in Saccharomycetaceae

    PubMed Central

    Hooks, Katarzyna B.; Delneri, Daniela; Griffiths-Jones, Sam

    2014-01-01

    Introns in protein-coding genes are very rare in hemiascomycetous yeast genomes. It has been suggested that these species have experienced extensive intron loss during their evolution from the postulated intron-rich fungal ancestor. However, no intron-devoid yeast species have been identified and some of the introns remaining within the genomes of intron-poor species, such as Saccharomyces cerevisiae, appear to be beneficial during growth under stress conditions. In order to reveal the pattern of intron retention within intron-poor yeast species and better understand the mechanisms of intron evolution, we generated a comprehensive set of 250 orthologous introns in the 20 species that comprise the Saccharomycetaceae, by analyzing RNA deep-sequencing data and alignments of intron-containing genes. Analysis of these intron sets shows that intron loss is at least two orders of magnitude more frequent than intron gain. Fine mapping of intron positions shows that intron sliding is rare, and that introns are almost always removed without changing the primary sequence of the encoded protein. The latter finding is consistent with the prevailing view that homologous recombination between reverse-transcribed mature mRNAs and the corresponding genomic locus is the primary mechanism of intron loss. However, we also find evidence that loss of a small number of introns is mediated by micro-homology, and that the number of intron losses is diminished in yeast species that have lost the microhomology end joining and nonhomologous end joining machinery. PMID:25364803

  16. Concrete Chemical Evolution

    SciTech Connect

    D.H. Tang

    1998-07-31

    The objectives of this analysis are to discuss and evaluate testing results that were performed for the M&O by the Pennsylvania State University (PSU) to evaluate the potential long-term evolution of organic admixtures in cementitious materials at elevated temperatures. The testing was designed to help provide a basis for a determination by the Performance Assessment group (PA) of the long-term acceptability and longevity of cementitious materials for repository use. The main purpose of the testing was to assess the evolution of gases (especially CO{sub 2}) from hydrated cement paste at elevated temperatures and to determine the impact on alkalinity, i.e., the pH value of cement paste pore solution. This information in turn can be used as scoping information to determine if further tests of this nature are needed to support PA. As part of this discussion and evaluation of the PSU results, an assessment of alkalinity in a ''cementitious repository'' and an evaluation of organic materials are presented.

  17. Evolution of molecular clouds

    NASA Technical Reports Server (NTRS)

    Sevenster, M.

    1993-01-01

    The evolution of interstellar molecular hydrogen was studied, with a special interest for the formation and evolution of molecular clouds and star formation within them, by a two-dimensional hydrodynamical simulation performed on a rectangular grid of physical sizes on the order of 100 pc. It is filled with an initial density of approx. 1 cm(exp -3), except for one cell (approx. 1 pc(exp 2)) at the center of the grid where an accretion core of 1-10(exp 3) solar masses is placed. The grid is co-moving with the gridcenter that is on a circular orbit around the Galactic center and that also is the guiding center of epicyclic approximation of orbits of the matter surrounding it. The initial radial velocity is zero; to account for differential rotation the initial tangential velocity (i.e. the movement around the galactic center) is proportional to the radial distance to the grid center. The rate is comparable to the rotation rate at the Local Standard of Rest. The influence of galactic rotation is noticed by spiral or elliptical forms, but on much longer time scales than self gravitation and cooling processes. Density and temperature are kept constant at the boundaries and no inflow is allowed along the tangential boundaries.

  18. Process Information and Evolution.

    PubMed

    Chastain, Erick; Smith, Cameron

    2016-12-01

    Universal Semantic Communication (USC) is a theory that models communication among agents without the assumption of a fixed protocol. We demonstrate a connection, via a concept we refer to as process information, between a special case of USC and evolutionary processes. In this context, one agent attempts to interpret a potentially arbitrary signal produced within its environment. Sources of this effective signal can be modeled as a single alternative agent. Given a set of common underlying concepts that may be symbolized differently by different sources in the environment, any given entity must be able to correlate intrinsic information with input it receives from the environment in order to accurately interpret the ambient signal and ultimately coordinate its own actions. This scenario encapsulates a class of USC problems that provides insight into the semantic aspect of a model of evolution proposed by Rivoire and Leibler. Through this connection, we show that evolution corresponds to a means of solving a special class of USC problems, can be viewed as a special case of the Multiplicative Weights Updates algorithm, and that infinite population selection with no mutation and no recombination conforms to the Rivoire-Leibler model. Finally, using process information we show that evolving populations implicitly internalize semantic information about their respective environments.

  19. Evolution of consciousness.

    PubMed

    Eccles, J C

    1992-08-15

    The hypothesis of the origin of consciousness is built upon the unique properties of the mammalian neocortex. The apical dendrites of the pyramidal cells bundle together as they ascend to lamina I to form neural receptor units of approximately 100 apical dendrites plus branches receiving hundreds of thousands of excitatory synapses, the collective assemblage being called a dendron. It is proposed that the whole world of consciousness, the mental world, is microgranular, with mental units called psychons, and that in mind-brain interaction one psychon is linked to one dendron through quantum physics. The hypothesis is that in mammalian evolution dendrons evolved for more effective integration of the increased complexity of sensory inputs. These evolved dendrons had the capacity for interacting with psychons that came to exist, so forming the mental world and giving the mammal conscious experiences. In Darwinian evolution, consciousness would have occurred initially some 200 million years ago in relation to the primitive cerebral cortices of evolving mammals. It would give global experiences of a surrounding world for guiding behavior beyond what is given by the unconscious operation of sensory cortical areas per se. So conscious experiences would give mammals evolutionary advantage over the reptiles, which lack a neocortex giving consciousness. The Wulst of the avian brain needs further investigation to discover how it could give birds the consciousness that they seem to have.

  20. Archaeology and cognitive evolution.

    PubMed

    Wynn, Thomas

    2002-06-01

    Archaeology can provide two bodies of information relevant to the understanding of the evolution of human cognition--the timing of developments, and the evolutionary context of these developments. The challenge is methodological. Archaeology must document attributes that have direct implications for underlying cognitive mechanisms. One example of such a cognitive archaeology is found in spatial cognition. The archaeological record documents an evolutionary sequence that begins with ape-equivalent spatial abilities 2.5 million years ago and ends with the appearance of modern abilities in the still remote past of 400,000 years ago. The timing of these developments reveals two major episodes in the evolution in spatial ability, one, 1.5 million years ago and the other, one million years later. The two episodes of development in spatial cognition had very different evolutionary contexts. The first was associated with the shift to an open country adaptive niche that occurred early in the time range of Homo erectus. The second was associated with no clear adaptive shift, though it does appear to have coincided with the invasion of more hostile environments and the appearance of systematic hunting of large mammals. Neither, however, occurred in a context of modern hunting and gathering.

  1. Thermodynamics of Terrestrial Evolution

    PubMed Central

    Kirkaldy, J. S.

    1965-01-01

    The causal element of biological evolution and development can be understood in terms of a potential function which is generalized from the variational principles of irreversible thermodynamics. This potential function is approximated by the rate of entropy production in a configuration space which admits of macroscopic excursions by fluctuation and regression as well as microscopic ones. Analogously to Onsager's dissipation function, the potential takes the form of a saddle surface in this configuration space. The path of evolution following from an initial high dissipation state within the fixed constraint provided by the invariant energy flux from the sun tends toward the stable saddle point by a series of spontaneous regressions which lower the entropy production rate and by an alternating series of spontaneous fluctuations which introduce new internal constraints and lead to a higher entropy production rate. The potential thus rationalizes the system's observed tendency toward “chemical imperialism” (high dissipation) while simultaneously accommodating the development of “dynamic efficiency” and complication (low dissipation). PMID:5884019

  2. Evolution of dietary antioxidants.

    PubMed

    Benzie, Iris F F

    2003-09-01

    Oxygen is vital for most organisms but, paradoxically, damages key biological sites. Oxygenic threat is met by antioxidants that evolved in parallel with our oxygenic atmosphere. Plants employ antioxidants to defend their structures against reactive oxygen species (ROS; oxidants) produced during photosynthesis. The human body is exposed to these same oxidants, and we have also evolved an effective antioxidant system. However, this is not infallible. ROS breach defences, oxidative damage ensues, accumulates with age, and causes a variety of pathological changes. Plant-based, antioxidant-rich foods traditionally formed the major part of the human diet, and plant-based dietary antioxidants are hypothesized to have an important role in maintaining human health. This hypothesis is logical in evolutionary terms, especially when we consider the relatively hypoxic environment in which humans may have evolved. In this paper, the human diet is discussed briefly in terms of its evolutionary development, different strategies of antioxidant defence are outlined, and evolution of dietary antioxidants is discussed from the perspectives of plant need and our current dietary requirements. Finally, possibilities in regard to dietary antioxidants, evolution, and human health are presented, and an evolutionary cost-benefit analysis is presented in relation to why we lost the ability to make ascorbic acid (vitamin C) although we retained an absolute requirement for it.

  3. Evolution of the tapetum.

    PubMed Central

    Schwab, Ivan R; Yuen, Carlton K; Buyukmihci, Nedim C; Blankenship, Thomas N; Fitzgerald, Paul G

    2002-01-01

    PURPOSE: To review, contrast, and compare current known tapetal mechanisms and review the implications for the evolution of the tapetum. METHODS: Ocular specimens of representative fish in key piscine families, including Acipenseridae, Cyprinidae, Chacidae; the reptilian family Crocodylidae; the mammalian family Felidae; and the Lepidopteran family Sphingidae were reviewed and compared histologically. All known varieties of tapeta were examined and classified and compared to the known cladogram representing the evolution of each specific family. RESULTS: Types of tapeta include tapetum cellulosum, tapetum fibrosum, retinal tapetum, invertebrate pigmented tapetum, and invertebrate thin-film tapetum. All but the invertebrate pigmented tapetum were examined histologically. Review of the evolutionary cladogram and comparison with known tapeta suggest that the tapetum evolved in the Devonian period 345 to 395 million years ago. Tapeta developed independently in at least three separate orders in invertebrates and vertebrates, and yet all have surprisingly similar mechanisms of light reflection, including thin-film interference, diffusely reflecting tapeta, Mie scattering, Rayleigh scattering, and perhaps orthogonal retroreflection. CONCLUSION: Tapeta are found in invertebrates and vertebrates and display different physical mechanisms of reflection. Each tapetum reflects the wavelengths most relevant to the species' ecological niche. With this work, we have hypothesized that the tapetum evolved independently in both invertebrates and vertebrates as early as the Devonian period and coincided with an explosion of life forms. PMID:12545693

  4. Hox genes and evolution

    PubMed Central

    Hrycaj, Steven M.; Wellik, Deneen M.

    2016-01-01

    Hox proteins are a deeply conserved group of transcription factors originally defined for their critical roles in governing segmental identity along the antero-posterior (AP) axis in Drosophila. Over the last 30 years, numerous data generated in evolutionarily diverse taxa have clearly shown that changes in the expression patterns of these genes are closely associated with the regionalization of the AP axis, suggesting that Hox genes have played a critical role in the evolution of novel body plans within Bilateria. Despite this deep functional conservation and the importance of these genes in AP patterning, key questions remain regarding many aspects of Hox biology. In this commentary, we highlight recent reports that have provided novel insight into the origins of the mammalian Hox cluster, the role of Hox genes in the generation of a limbless body plan, and a novel putative mechanism in which Hox genes may encode specificity along the AP axis. Although the data discussed here offer a fresh perspective, it is clear that there is still much to learn about Hox biology and the roles it has played in the evolution of the Bilaterian body plan. PMID:27239281

  5. Thermal evolution of the earth

    NASA Technical Reports Server (NTRS)

    Spohn, T.

    1984-01-01

    The earth's heat budget and models of the earth's thermal evolution are discussed. Sources of the planetary heat are considered and modes of heat transport are addressed, including conduction, convection, and chemical convection. Thermal and convectional models of the earth are covered, and models of thermal evolution are discussed in detail, including changes in the core, the influence of layered mantle convection on the thermal evolution, and the effect of chemical differentiation on the continents.

  6. Type Evolution and Instance Adaptation

    DTIC Science & Technology

    1992-03-02

    Schema evolution support is an important facility for object-oriented database (OODB) systems. While existing OODB systems provide for limited forms...of evolution , including modification to the database schema and reorganization of affected instances, we find their support insufficient. Specific...database. This paper examines the limitations of existing schemes, and offers a more general framework for specifying and reasoning about the evolution

  7. Thermal evolution of Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    Lunine, Jonathan I.; Rizk, Bashar

    1989-01-01

    The present model of Titan's atmosphere/surface evolution assumes the presence of a kilometer-deep ethane-methane ocean at the surface that serves as a tropospheric thermal balance-determining atmospheric-gas reservoir. The evolution of the atmospheric thermal structure is driven by gas-abundance changes occurring as stratospheric photolysis irreversibly converts methane into higher hydrocarbons, whereby the ocean becomes ethane-enriched and methane-depleted. A family of evolution models is presented whose various members correspond to different present-day ocean compositions, various atmospheric hydrogen abundances, and different schemes for frequency-averaging the gas opacity. A slow evolution over several billion years is envisioned.

  8. Chemical evolution of dense clouds

    NASA Technical Reports Server (NTRS)

    Chappelle, E. W.; Donn, B. D.; Payne, W. A., Jr.; Stief, L. J.

    1972-01-01

    Chemical processes that could determine the molecular composition of the cloud during the several stages of its evolution are considered. Reactions at the relatively interstellar densities are emphasized.

  9. QCD Evolution in Dense Medium

    NASA Astrophysics Data System (ADS)

    Gay Ducati, M. B.

    The dynamics of the partonic distribution is a main concern in high energy physics, once it provides the initial condition for the Heavy Ion colliders. The determination of the evolution equation which drives the partonic behavior is subject of great interest since is connected to the observables. This lecture aims to present a brief review of the evolution equations that describe the partonic dynamics at high energies. First the linear evolution equations (DGLAP and BFKL) are presented. Then, the formulations developed to deal with the high density effects, which originate the non-linear evolution equations (GLR, AGL, BK, JIMWLK) are discussed, as well as an example of related phenomenology.

  10. Evolution of Vision

    NASA Astrophysics Data System (ADS)

    Ostrovsky, Mikhail

    The evolution of photoreception, giving rise to eye, offers a kaleidoscopic view on selection acting at both the organ and molecular levels. The molecular level is mainly considered in the lecture. The greatest progress to date has been made in relation to the opsin visual pigments. Opsins appeared before eyes did. Two- and three-dimensional organization for rhodopsin in the rod outer segment disk membrane, as well as molecular mechanisms of visual pigments spectral tuning, photoisomerization and also opsin as a G-protein coupled receptor are considered. Molecular mechanisms of visual pigments spectral tuning, namely switching of chromophore (physiological time scale) and amino acid changes in the chromophore site of opsin (evolutionary time scale) is considered in the lecture. Photoisomerization of rhodopsin chromophore, 11-cis retinal is the only photochemical reaction in vision. The reaction is extemely fast (less that 200 fs) and high efficient (. is 0.65). The rhodopsin photolysis and kinetics of the earlier products appearance, photo- and bathorhodopsin, is considered. It is known that light is not only a carrier of information, but also a risk factor of damage to the eye. This photobiological paradox of vision is mainly due to the nature of rhodopsin chromophore. Photooxidation is the base of the paradox. All factors present in the phototrceptor cells to initiate free-radical photooxidation: photosensitizers, oxygen and substrates of oxidation: lipids and proteins (opsin). That is why photoprotective system of the eye structures appeared in the course of evolution. Three lines of protective system to prevent light damage to the retina and retina pigment epithelium is known: permanent renewal of rod and cone outer segment, powerful antioxidant system and optical media as cut-off filters where the lens is a key component. The molecular mechanisms of light damage to the eye and photoprotective system of the eye is considered in the lecture. The molecular

  11. Biological evolution and behavioral evolution: two approaches to altruism.

    PubMed

    Rachlin, Howard; Locey, Matthew L; Safin, Vasiliy

    2013-02-01

    Altruism may be learned (behavioral evolution) in a way similar to that proposed in the target article for its biological evolution. Altruism (over social space) corresponds to self-control (over time). In both cases, one must learn to ignore the rewards to a particular (person or moment) and behave to maximize the rewards to a group (of people or moments).

  12. Evolution education in Canada's museums: Where is human evolution?

    NASA Astrophysics Data System (ADS)

    Bean, Sarah

    While an interest in the origin of human beings may be a cultural universal, there are various views and beliefs about how this event took place. In Canada, a recent (2010) Angus Reid survey revealed that only 61% of Canadians accepted that humans evolved over millions of years; 39% of the population either believed in creationism or did not accept evolution as a scientific fact. These statistics suggest that human evolution education is a topic that needs to be addressed. This thesis investigates the role of museums in public education about human evolution. Prior to this study, the number of Canadian museums with exhibits about this topic was unknown. Sixteen Canadian museums participated in this study, and the results demonstrated that only two had permanent exhibits on human evolution, and one creationist museum presented a biblically-based account of human origins. Here, it is argued that more of Canada's museums should consider incorporating human evolution education into their mandates.

  13. Raptors and primate evolution.

    PubMed

    McGraw, W Scott; Berger, Lee R

    2013-01-01

    Most scholars agree that avoiding predators is a central concern of lemurs, monkeys, and apes. However, given uncertainties about the frequency with which primates actually become prey, the selective importance of predation in primate evolution continues to be debated. Some argue that primates are often killed by predators, while others maintain that such events are relatively rare. Some authors have contended that predation's influence on primate sociality has been trivial; others counter that predation need not occur often to be a powerful selective force. Given the challenges of documenting events that can be ephemeral and irregular, we are unlikely ever to amass the volume of systematic, comparative data we have on such topics as feeding, social dynamics, or locomotor behavior. Nevertheless, a steady accumulation of field observations, insight gained from natural experiments, and novel taphonomic analyses have enhanced understanding of how primates interact with several predators, especially raptors, the subject of this review.

  14. Evolution of microbial markets

    PubMed Central

    Werner, Gijsbert D. A.; Strassmann, Joan E.; Ivens, Aniek B. F.; Engelmoer, Daniel J. P.; Verbruggen, Erik; Queller, David C.; Noë, Ronald; Johnson, Nancy Collins; Hammerstein, Peter; Kiers, E. Toby

    2014-01-01

    Biological market theory has been used successfully to explain cooperative behavior in many animal species. Microbes also engage in cooperative behaviors, both with hosts and other microbes, that can be described in economic terms. However, a market approach is not traditionally used to analyze these interactions. Here, we extend the biological market framework to ask whether this theory is of use to evolutionary biologists studying microbes. We consider six economic strategies used by microbes to optimize their success in markets. We argue that an economic market framework is a useful tool to generate specific and interesting predictions about microbial interactions, including the evolution of partner discrimination, hoarding strategies, specialized versus diversified mutualistic services, and the role of spatial structures, such as flocks and consortia. There is untapped potential for studying the evolutionary dynamics of microbial systems. Market theory can help structure this potential by characterizing strategic investment of microbes across a diversity of conditions. PMID:24474743

  15. Viral quasispecies evolution.

    PubMed

    Domingo, Esteban; Sheldon, Julie; Perales, Celia

    2012-06-01

    Evolution of RNA viruses occurs through disequilibria of collections of closely related mutant spectra or mutant clouds termed viral quasispecies. Here we review the origin of the quasispecies concept and some biological implications of quasispecies dynamics. Two main aspects are addressed: (i) mutant clouds as reservoirs of phenotypic variants for virus adaptability and (ii) the internal interactions that are established within mutant spectra that render a virus ensemble the unit of selection. The understanding of viruses as quasispecies has led to new antiviral designs, such as lethal mutagenesis, whose aim is to drive viruses toward low fitness values with limited chances of fitness recovery. The impact of quasispecies for three salient human pathogens, human immunodeficiency virus and the hepatitis B and C viruses, is reviewed, with emphasis on antiviral treatment strategies. Finally, extensions of quasispecies to nonviral systems are briefly mentioned to emphasize the broad applicability of quasispecies theory.

  16. Evolution and climate variability

    SciTech Connect

    Potts, R.

    1996-08-16

    Variations in organisms are preserved and accrue if there is a consistent bias in selection over many generations. This idea of long-term directional selection has been embraced to explain major adaptive change. It is widely thought that important adaptive shifts in hominids corresponded with directional environmental change. This view, which echoes the savanna scenario of hominid evolution, has strongly been supported by paleontologists and paleoclimatologists over the past decade. The origin of the hominids, bipedality, stone toolmaking, and brain size increase have all been related to cooling, aridification, and savanna expansion. However there appears to be a more prominent signal than the aridity trend: an increase in the range of climatic variation over time. This article discusses the possible reprocussions of this interpertation. 13 refs.

  17. Evolution of microbial markets.

    PubMed

    Werner, Gijsbert D A; Strassmann, Joan E; Ivens, Aniek B F; Engelmoer, Daniel J P; Verbruggen, Erik; Queller, David C; Noë, Ronald; Johnson, Nancy Collins; Hammerstein, Peter; Kiers, E Toby

    2014-01-28

    Biological market theory has been used successfully to explain cooperative behavior in many animal species. Microbes also engage in cooperative behaviors, both with hosts and other microbes, that can be described in economic terms. However, a market approach is not traditionally used to analyze these interactions. Here, we extend the biological market framework to ask whether this theory is of use to evolutionary biologists studying microbes. We consider six economic strategies used by microbes to optimize their success in markets. We argue that an economic market framework is a useful tool to generate specific and interesting predictions about microbial interactions, including the evolution of partner discrimination, hoarding strategies, specialized versus diversified mutualistic services, and the role of spatial structures, such as flocks and consortia. There is untapped potential for studying the evolutionary dynamics of microbial systems. Market theory can help structure this potential by characterizing strategic investment of microbes across a diversity of conditions.

  18. Evolution and Impartiality*

    PubMed Central

    Kahane, Guy

    2014-01-01

    Lazari-Radek and Singer argue that evolutionary considerations can resolve Sidgwick’s dualism of practical reason, because such considerations debunk moral views that give weight to self-interested or partial considerations, but cannot threaten the principle Universal Benevolence. I argue that even if we grant these claims, this appeal to evolution is ultimately self-defeating. Lazari-Radek and Singer face a dilemma. Either their evolutionary argument against partial morality succeeds, but then we need to also give up our conviction that suffering is bad; or there is a way to defend this conviction, but then their argument against partiality fails. Utilitarians, I suggest, should resist the temptation to appeal to evolutionary debunking arguments. PMID:24711673

  19. Viral Quasispecies Evolution

    PubMed Central

    Sheldon, Julie; Perales, Celia

    2012-01-01

    Summary: Evolution of RNA viruses occurs through disequilibria of collections of closely related mutant spectra or mutant clouds termed viral quasispecies. Here we review the origin of the quasispecies concept and some biological implications of quasispecies dynamics. Two main aspects are addressed: (i) mutant clouds as reservoirs of phenotypic variants for virus adaptability and (ii) the internal interactions that are established within mutant spectra that render a virus ensemble the unit of selection. The understanding of viruses as quasispecies has led to new antiviral designs, such as lethal mutagenesis, whose aim is to drive viruses toward low fitness values with limited chances of fitness recovery. The impact of quasispecies for three salient human pathogens, human immunodeficiency virus and the hepatitis B and C viruses, is reviewed, with emphasis on antiviral treatment strategies. Finally, extensions of quasispecies to nonviral systems are briefly mentioned to emphasize the broad applicability of quasispecies theory. PMID:22688811

  20. Early stellar evolution

    NASA Technical Reports Server (NTRS)

    Stahler, Steven W.

    1994-01-01

    Research into the formation and early evolution of stars is currently an area of great interest and activity. The theoretical and observational foundations for this development are reviewed in this paper. By now, the basic physics governing cloud collapse is well understood, as is the structure of the resulting protostars. However, the theory predicts protostellar luminosities that are greater than those of most infrared sources. Observationally, it is thought that protostars emit powerful winds that push away remnant cloud gas, but both the origin of these winds and the nature of their interaction with ambient gas are controversial. Finally, the theory of pre-main-sequence stars has been modified to incorporate more realistic initial conditions. This improvement helps to explain the distribution of such stars in the H-R diagram. Many important issues, such as the origin of binary stars and stellar clusters, remain as challenges for future research.

  1. Evolution in slow motion

    NASA Image and Video Library

    2015-09-14

    It is known today that merging galaxies play a large role in the evolution of galaxies and the formation of elliptical galaxies in particular. However there are only a few merging systems close enough to be observed in depth. The pair of interacting galaxies picture seen here — known as NGC 3921 — is one of these systems. NGC 3921 — found in the constellation of Ursa Major (The Great Bear) — is an interacting pair of disc galaxies in the late stages of its merger. Observations show that both of the galaxies involved were about the same mass and collided about 700 million years ago. You can see clearly in this image the disturbed morphology, tails and loops characteristic of a post-merger. The clash of galaxies caused a rush of star formation and previous Hubble observations showed over 1000 bright, young star clusters bursting to life at the heart of the galaxy pair.

  2. The evolution of inequality.

    PubMed

    Mattison, Siobhán M; Smith, Eric A; Shenk, Mary K; Cochrane, Ethan E

    2016-07-01

    Understanding how systems of political and economic inequality evolved from relatively egalitarian origins has long been a focus of anthropological inquiry. Many hypotheses have been suggested to link socio-ecological features with the rise and spread of inequality, and empirical tests of these hypotheses in prehistoric and extant societies are increasing. In this review, we synthesize several streams of theory relevant to understanding the evolutionary origins, spread, and adaptive significance of inequality. We argue that while inequality may be produced by a variety of localized processes, its evolution is fundamentally dependent on the economic defensibility and transmissibility of wealth. Furthermore, these properties of wealth could become persistent drivers of inequality only following a shift to a more stable climate in the Holocene. We conclude by noting several key areas for future empirical research, emphasizing the need for more analyses of contemporary shifts toward institutionalized inequality as well as prehistoric cases.

  3. Current evolution of meteoroids

    NASA Technical Reports Server (NTRS)

    Dohnanyi, J. S.

    1973-01-01

    The observed mass distribution of meteoroids at 1 AU from the sun is briefly reviewed in a survey that ranges over the bulk of the mass spectrum from micrometeoroids to meteorite parent objects. The evolution of meteoroids under the influence of collisions, planetary perturbations, the Poynting-Robertson effect and radiation pressure is then discussed. Most micrometeoroids are expelled from the solar system by radiation pressure shortly after their production as secondary ejecta during impact by larger objects or as dust ejected by comets. Particles that survive will eventually be swept out by the Poynting-Robertson effect. Meteoroids in the radio and photographic ranges are destroyed in collisions faster than they can be replaced by the production of secondary fragments during collisions between larger objects.

  4. [Evolution of mitochondria].

    PubMed

    Litoshenko, A Ia

    2002-01-01

    Until recently, the origin and evolution of mitochondria was explained by the serial endosymbiosis hypothesis. This hypothesis posits that contemporary mitochondria are the direct descendants of a bacterial endosymbiont, which was settled in a nucleus-containing amitochondriate host cell. Results of the mitochondrial gene sequences support a monophyletic origin of the mitochondria from a single eubacterial ancestor shared with a subdivision of the alpha-proteobacteria. In recent years, the complete sequences of the vast variety of mitochondrial and eubacterial genomes were determined. These data indicate that the mitochondrial genome evolved from a common ancestor of all extant eukaryotes and assume a possibility that the mitochondrial and nuclear constituents of the eukaryotic cell originated simultaneously.

  5. The evolution of 'bricolage'.

    PubMed

    Duboule, D; Wilkins, A S

    1998-02-01

    The past ten years of developmental genetics have revealed that most of our genes are shared by other species throughout the animal kingdom. Consequently, animal diversity might largely rely on the differential use of the same components, either at the individual level through divergent functional recruitment, or at a more integrated level, through their participation in various genetic networks. Here, we argue that this inevitably leads to an increase in the interdependency between functions that, in turn, influences the degree to which novel variations can be tolerated. In this 'transitionist' scheme, evolution is neither inherently gradualist nor punctuated but, instead, progresses from one extreme to the other, together with the increased complexity of organisms.

  6. Evolution of working memory

    PubMed Central

    Carruthers, Peter

    2013-01-01

    Working memory (WM) is fundamental to many aspects of human life, including learning, speech and text comprehension, prospection and future planning, and explicit “system 2” forms of reasoning, as well as overlapping heavily with fluid general intelligence. WM has been intensively studied for many decades, and there is a growing consensus about its nature, its components, and its signature limits. Remarkably, given its central importance in human life, there has been very little comparative investigation of WM abilities across species. Consequently, much remains unknown about the evolution of this important human capacity. Some questions can be tentatively answered from the existing comparative literature. Even studies that were not intended to do so can nonetheless shed light on the WM capacities of nonhuman animals. However, many questions remain. PMID:23754428

  7. Evolution and public health

    PubMed Central

    Omenn, Gilbert S.

    2009-01-01

    Evolution and its elements of natural selection, population migration, genetic drift, and founder effects have shaped the world in which we practice public health. Human cultures and technologies have modified life on this planet and have coevolved with myriad other species, including microorganisms; plant and animal sources of food; invertebrate vectors of disease; and intermediate hosts among birds, mammals, and nonhuman primates. Molecular mechanisms of differential resistance or susceptibility to infectious agents or diets have evolved and are being discovered with modern methods. Some of these evolutionary relations require a perspective of tens of thousands of years, whereas other changes are observable in real time. The implications and applications of evolutionary understanding are important to our current programs and policies for infectious disease surveillance, gene–environment interactions, and health disparities globally. PMID:19966311

  8. Allergy in evolution.

    PubMed

    Platts-Mills, Thomas A E

    2012-01-01

    The 'foreignness' of proteins that we encounter in our homes and outdoors is in large part dependent on their evolutionary distance from man. This is relevant to understanding the differences between mammalian allergens, e.g. cats, and arthropod allergens, e.g. mites and cockroaches, as well as to understanding responses to a wide range of food allergens. On the other hand, allergic disease has gone through a major evolution of its own from a prehygiene state where there is minimal production of allergen-specific IgE, to the production of high-titer IgE, and then to the dramatic increase in asthma. The challenge is to understand how changes in both hygiene and lifestyle have contributed to the changes in allergic disease. Copyright © 2012 S. Karger AG, Basel.

  9. Evolution of Biological Complexity

    NASA Astrophysics Data System (ADS)

    Goldstein, Raymond E.

    It is a general rule of nature that larger organisms are more complex, at least as measured by the number of distinct types of cells present. This reflects the fitness advantage conferred by a division of labor among specialized cells over homogeneous totipotency. Yet, increasing size has both costs and benefits, and the search for understanding the driving forces behind the evolution of multicellularity is becoming a very active area of research. This article presents an overview of recent experimental and theoretical work aimed at understanding this biological problem from the perspective of physics. For a class of model organisms, the Volvocine green algae, an emerging hypothesis connects the transition from organisms with totipotent cells to those with terminal germ-soma differentiation to the competition between diffusion and fluid advection created by beating flagella. A number of challenging problems in fluid dynamics, nonlinear dynamics, and control theory emerge when one probes the workings of the simplest multicellular organisms.

  10. [Metalworking industry management evolution].

    PubMed

    Mattucci, Massimo

    2011-01-01

    Analysis of the evolution drivers of the management systems in the metalworking industry, mainly characterized as "automotive", starting with the "mass production" model, followed for the development of Italian industry in the '50. Through the socio-economic changes of the '90/10, the metalworking plants were deeply restructured with the introduction of computers in the production systems, and then with the first global benchmarks such as the "lean production", towards the needed operational flexibility to respond to the market dynamics. Plants change radically, company networks become real, ICT services are fundamental elements for the integration. These trends help visualizing a new "Factory of the Future" for the years 2020/30, where the competition will be based on the socio-economical, technological and environmental factors included in the "Competitive Sustainable Manufacturing" paradigm.

  11. Early stellar evolution

    NASA Technical Reports Server (NTRS)

    Stahler, Steven W.

    1994-01-01

    Research into the formation and early evolution of stars is currently an area of great interest and activity. The theoretical and observational foundations for this development are reviewed in this paper. By now, the basic physics governing cloud collapse is well understood, as is the structure of the resulting protostars. However, the theory predicts protostellar luminosities that are greater than those of most infrared sources. Observationally, it is thought that protostars emit powerful winds that push away remnant cloud gas, but both the origin of these winds and the nature of their interaction with ambient gas are controversial. Finally, the theory of pre-main-sequence stars has been modified to incorporate more realistic initial conditions. This improvement helps to explain the distribution of such stars in the H-R diagram. Many important issues, such as the origin of binary stars and stellar clusters, remain as challenges for future research.

  12. Evolution of Metals

    NASA Astrophysics Data System (ADS)

    Shull, J. M.

    1998-05-01

    This review will cover a mystery story. Actually, two mysteries of the Structure and Evolution of the Universe involving the history of the baryons and the chemical elements synthesized in the first stars. When did the gas and metals first form? How did they evolve to their current distribution? The original crime scene is unknown, but evidence has been collected in the diffuse intergalactic medium and in hot intracluster gas. In these scattered locales, large amounts of gas has accumulated, contaminated by heavy elements from the first stars. Unfortunately, some of the evidence has been destroyed by gravity. Also, the earliest quasars, massive stars, and supernovae altered the physical state of the gas and transported the elements far from the original scene. I will briefly review current observations and theories relevant to these processes and suggest ways in which future NASA missions could constrain the many speculative ideas on this subject.

  13. Directed Polymerase Evolution

    PubMed Central

    Chen, Tingjian; Romesberg, Floyd E.

    2014-01-01

    Polymerases evolved in nature to synthesize DNA and RNA, and they underlie the storage and flow of genetic information in all cells. The availability of these enzymes for use at the bench has driven a revolution in biotechnology and medicinal research; however, polymerases did not evolve to function efficiently under the conditions required for some applications and their high substrate fidelity precludes their use for most applications that involve modified substrates. To circumvent these limitations, researchers have turned to directed evolution to tailor the properties and/or substrate repertoire of polymerases for different applications, and several systems have been developed for this purpose. These systems draw on different methods of creating a pool of randomly mutated polymerases and are differentiated by the process used to isolate the most fit members. A variety of polymerases have been evolved, providing new or improved functionality, as well as interesting new insight into the factors governing activity. PMID:24211837

  14. Evolution of biological information.

    PubMed

    Schneider, T D

    2000-07-15

    How do genetic systems gain information by evolutionary processes? Answering this question precisely requires a robust, quantitative measure of information. Fortunately, 50 years ago Claude Shannon defined information as a decrease in the uncertainty of a receiver. For molecular systems, uncertainty is closely related to entropy and hence has clear connections to the Second Law of Thermodynamics. These aspects of information theory have allowed the development of a straightforward and practical method of measuring information in genetic control systems. Here this method is used to observe information gain in the binding sites for an artificial 'protein' in a computer simulation of evolution. The simulation begins with zero information and, as in naturally occurring genetic systems, the information measured in the fully evolved binding sites is close to that needed to locate the sites in the genome. The transition is rapid, demonstrating that information gain can occur by punctuated equilibrium.

  15. SIM Configuration Evolution

    NASA Technical Reports Server (NTRS)

    Aaron, Kim M.

    2000-01-01

    The Space Interferometry Mission (SIM) is a space-based 10 m baseline Michelson interferometer. Planned for launch in 2005 aboard a Delta III launch vehicle, or equivalent, its primary objective is to measure the positions of stars and other celestial objects with an unprecedented accuracy of 4 micro arc seconds. With such an instrument, tremendous advancement can be expected in our understanding of stellar and galactic dynamics. Using triangulation from opposite sides of the orbit around the sun (i.e. by using parallax) one can measure the distance to any observable object in our galaxy. By directly measuring the orbital wobble of nearby stars, the mass and orbit of planets can be determined over a wide range of parameters. The distribution of velocity within nearby galaxies will be measurable. Observations of these and other objects will improve the calibration of distance estimators by more than an order of magnitude. This will permit a much better determination of the Hubble Constant as well as improving our overall understanding of the evolution of the universe. SIM has undergone several transformations, especially over the past year and a half since the start of Phase A. During this phase of a project, it is desirable to perform system-level trade studies, so the substantial evolution of the design that has occurred is quite appropriate. Part of the trade-off process has addressed two major underlying architectures: SIM Classic; and Son of SIM. The difference between these two architectures is related to the overall arrangement of the optical elements and the associated metrology system. Several different configurations have been developed for each architecture. Each configuration is the result of design choices that are influenced by many competing considerations. Some of the more important aspects will be discussed. The Space Interferometry Mission has some extremely challenging goals: millikelvin thermal stability, nanometer stabilization of optics

  16. Palaeoenvironments and hominoid evolution.

    PubMed

    Pickford, Martin

    2002-03-01

    One of the key features that separates humans and their closest relatives (extinct species of the genus Homo and Praeanthropus and the australopithecines Australopithecus and Paranthropus) on the one hand, from the other hominoids, on the other, is their obligate bipedal locomotion when on the ground. This major difference from the generally quadrupedal locomotion practiced by other hominoids (Pan, Gorilla, Pongo and many extinct lineages) is reflected in many parts of the body, including all the major bones in the legs, arms, trunk and cranium. Locomotion has thus been of major interest to those interested in human origins, evolution, classification and phylogeny. A major hurdle to studies of the origins of bipedalism concerns the paucity of African hominoid fossils between 15 Ma, when all the adequately known hominoids were quadrupedal (most were pronograde, but at least one lineage was orthograde), and 4.2 Ma by which time fully bipedal hominids were established in Africa. Examination of Old World geology and palaeontology reveals a great deal about the evolution of palaeoenvironments and faunas during this period, and it is suggested that hominids evolved bipedal locomotion at the same time that there was a fundamental reorganisation of faunas towards the end of the Miocene. This faunal turnover resulted in the establishment of faunal lineages of "modern" aspect in Africa at the expense of "archaic" lineages which either went extinct or suffered a diminution of diversity. Many of the "modern" lineages were adapted to open country habitats in which grass became a major component of the diet as shown by modifications in the cheek teeth. Hominoids, in contrast, retained their traditional diet but were obliged to forage over greater and greater areas in order to do so, and this tactic led to pressures to modify the locomotor system rather than the diet. If bipedal hominids originated during this period, then the family Hominidae (sensu stricto) dates from about 8

  17. Elements of metabolic evolution.

    PubMed

    Huber, Claudia; Kraus, Florian; Hanzlik, Marianne; Eisenreich, Wolfgang; Wächtershäuser, Günter

    2012-02-13

    Research into the origin of evolution is polarized between a genetics-first approach, with its focus on polymer replication, and a metabolism-first approach that takes aim at chemical reaction cycles. Taking the latter approach, we explored reductive carbon fixation in a volcanic hydrothermal setting, driven by the chemical potential of quenched volcanic fluids for converting volcanic C1 compounds into organic products by transition-metal catalysts. These catalysts are assumed to evolve by accepting ever-new organic products as ligands for enhancing their catalytic power, which in turn enhances the rates of synthetic pathways that give rise to ever-new organic products, with the overall effect of a self-expanding metabolism. We established HCN, CO, and CH(3)SH as carbon nutrients, CO and H(2) as reductants, and iron-group transition metals as catalysts. In one case, we employed the "cyano-system" [Ni(OH)(CN)] with [Ni(CN)(4)](2-) as the dominant nickel-cyano species. This reaction mainly produced α-amino acids and α-hydroxy acids as well as various intermediates and derivatives. An organo-metal-catalyzed mechanism is suggested that mainly builds carbon skeletons by repeated cyano insertions, with minor CO insertions in the presence of CO. The formation of elemental nickel (Ni(0)) points to an active reduced-nickel species. In another case, we employed the mercapto-carbonyl system [Co(2)(CO)(8)]/Ca(OH)(2)/CO for the double-carbonylation of mercaptans. In a "hybrid system", we combined benzyl mercaptan with the cyano system, in which [Ni(OH)(CN)] was the most productive for the double-carbon-fixation reaction. Finally, we demonstrated that the addition of products of the cyano system (Gly, Ala) to the hybrid system increased productivity. These results demonstrate the chemical possibility of metabolic evolution through rate-promotion of one synthetic reaction by the products of another.

  18. Case A Binary Evolution

    SciTech Connect

    Nelson, C A; Eggleton, P P

    2001-03-28

    We undertake a comparison of observed Algol-type binaries with a library of computed Case A binary evolution tracks. The library consists of 5500 binary tracks with various values of initial primary mass M{sub 10}, mass ratio q{sub 0}, and period P{sub 0}, designed to sample the phase-space of Case A binaries in the range -0.10 {le} log M{sub 10} {le} 1.7. Each binary is evolved using a standard code with the assumption that both total mass and orbital angular momentum are conserved. This code follows the evolution of both stars until the point where contact or reverse mass transfer occurs. The resulting binary tracks show a rich variety of behavior which we sort into several subclasses of Case A and Case B. We present the results of this classification, the final mass ratio and the fraction of time spent in Roche Lobe overflow for each binary system. The conservative assumption under which we created this library is expected to hold for a broad range of binaries, where both components have spectra in the range G0 to B1 and luminosity class III - V. We gather a list of relatively well-determined observed hot Algol-type binaries meeting this criterion, as well as a list of cooler Algol-type binaries where we expect significant dynamo-driven mass loss and angular momentum loss. We fit each observed binary to our library of tracks using a {chi}{sup 2}-minimizing procedure. We find that the hot Algols display overall acceptable {chi}{sup 2}, confirming the conservative assumption, while the cool Algols show much less acceptable {chi}{sup 2} suggesting the need for more free parameters, such as mass and angular momentum loss.

  19. Thermal Evolution of Mercury

    NASA Astrophysics Data System (ADS)

    Multhaup, K.

    2008-09-01

    A 1D thermal evolution model of Mercury is presented. Refer to Fig. 1 for a sketch. Mercury is assumed to consist of a dense, initially entirely fluid iron-rich core surrounded by a convecting silicate mantle with a conducting immobile layer on top. Heating is provided by radiogenic decay. As the planet evolves, an inner core may freeze out and the mantle may differentiate by forming a basaltic crust. As our current knowledge of Mercury provides poor constraints on key parameters including mantle rheology, sulphur contents of the core or radiogenic heat sources, a broad range of contrasting values is used to create thermal histories of the innermost planet of the solar system. The proposed evolutions of mantle temperature, core adiabat and stagnant lid thickness provide starting points for considerations pertaining to a possible core dynamo, interior and exterior heat flows, characteristics of the mantle-crust system, impact events and the Hermian gravity field. For given parameters, mantle convection is likely to have continued until the present day. Inner cores of pure iron—either completely frozen out or engulfed in a spherical liquid shell—are obtained only if "wet" mantle rheology is assumed. Results from earlier and current studies and data obtained by Mariner 10 or ground-based studies are used to evaluate the various model outcomes, but insight expected from the BepiColombo or MESSENGER missions is required to further limit the parameter space. The present-day ratio of Mercury's inner and outer cores as determined by the core sulphur content is shown in Fig. 2 for an initially volatile-rich (A) and refractory-rich (B) mantle-crust system. Trends in results characterizing the present-day Hermian mantlecrust system are shown in Fig. 3.

  20. Evolution of Mercury's Obliquity

    NASA Astrophysics Data System (ADS)

    Yseboodt, M.; Margot, J. L.

    2005-05-01

    Mercury has a near-zero obliquity, i.e. its spin axis is nearly perpendicular to its orbital plane. In order to constrain the size of the planet's core with the framework suggested by Peale (1976), the obliquity must be known precisely. Rambaux and Bois (2004) have suggested that Mercury's obliquity varies on thousand-year timescales due to planetary perturbations, potentially ruining the feasibility of Peale's experiment. We use a Hamiltonian approach (free of energy dissipation) to study the spin-orbit evolution of Mercury subject to planetary perturbations. We can reproduce an obliquity evolution similar to that of Rambaux and Bois (2004) if we introduce the planetary perturbations abruptly, i.e. by a step function. But if we introduce the planetary effects smoothly starting from an equilibrium position corresponding to the Cassini state (where the spin axis, the normal to the invariable plane and the normal to the orbital plane are aligned), the thousand-year oscillations in the obliquity do not appear. We find an equilibrium value for the obliquity of ˜1.6 arcmin for (B-A)/C = 1.2 10-4 and (C-A)/C = 2.4 10-4, which are combinations of the moments of inertia corresponding to the Mariner 10 gravity data. Our results indicate that planetary perturbations do not force short-period oscillations in Mercury's obliquity, even though such oscillations may appear in numerical integrations involving artificial departures from the Cassini state or the sudden onset of perturbations. Peale (2004) has shown that the periods of damping of the free motions (free precession or free libration) are short compared to the age of the solar system, such that oscillations in obliquity are expected to decay. In the absence of excitation processes, Mercury's obliquity will remain constant, suggesting that one of the important conditions for the success of Peale's experiment is realized.

  1. Early bioenergetic evolution

    PubMed Central

    Sousa, Filipa L.; Thiergart, Thorsten; Landan, Giddy; Nelson-Sathi, Shijulal; Pereira, Inês A. C.; Allen, John F.; Lane, Nick; Martin, William F.

    2013-01-01

    Life is the harnessing of chemical energy in such a way that the energy-harnessing device makes a copy of itself. This paper outlines an energetically feasible path from a particular inorganic setting for the origin of life to the first free-living cells. The sources of energy available to early organic synthesis, early evolving systems and early cells stand in the foreground, as do the possible mechanisms of their conversion into harnessable chemical energy for synthetic reactions. With regard to the possible temporal sequence of events, we focus on: (i) alkaline hydrothermal vents as the far-from-equilibrium setting, (ii) the Wood–Ljungdahl (acetyl-CoA) pathway as the route that could have underpinned carbon assimilation for these processes, (iii) biochemical divergence, within the naturally formed inorganic compartments at a hydrothermal mound, of geochemically confined replicating entities with a complexity below that of free-living prokaryotes, and (iv) acetogenesis and methanogenesis as the ancestral forms of carbon and energy metabolism in the first free-living ancestors of the eubacteria and archaebacteria, respectively. In terms of the main evolutionary transitions in early bioenergetic evolution, we focus on: (i) thioester-dependent substrate-level phosphorylations, (ii) harnessing of naturally existing proton gradients at the vent–ocean interface via the ATP synthase, (iii) harnessing of Na+ gradients generated by H+/Na+ antiporters, (iv) flavin-based bifurcation-dependent gradient generation, and finally (v) quinone-based (and Q-cycle-dependent) proton gradient generation. Of those five transitions, the first four are posited to have taken place at the vent. Ultimately, all of these bioenergetic processes depend, even today, upon CO2 reduction with low-potential ferredoxin (Fd), generated either chemosynthetically or photosynthetically, suggesting a reaction of the type ‘reduced iron → reduced carbon’ at the beginning of bioenergetic evolution

  2. America's Anti-Evolution Movement

    ERIC Educational Resources Information Center

    Moore, Randy

    2002-01-01

    Evolution is the cornerstone of biology and one of the most powerful, exciting, and well-supported laws in modern science. Evolution transforms biology from a collection of unrelated observations and definitions into a coherent discipline that, among other things, helps people understand life's history and predict answers to important research…

  3. Evolution & the Cesarean Section Rate

    ERIC Educational Resources Information Center

    Walsh, Joseph A.

    2008-01-01

    "Nothing in biology makes sense except in the light of evolution." This was the title of an essay by geneticist Theodosius Dobzhansky writing in 1973. Many causes have been given for the increased Cesarean section rate in developed countries, but biologic evolution has not been one of them. The C-section rate will continue to rise, because the…

  4. A Teaching Guide to Evolution

    ERIC Educational Resources Information Center

    Gregg, Thomas G.; Janssen, Gary R.; Bhattacharjee, J.K.

    2003-01-01

    Evolution is considered by virtually all biologists to be the central unifying principle of biology, yet its fundamental concepts are not widely understood or widely disseminated. Teaching evolution--defined as descent with modification from a common ancestor as a result of natural selection acting on genetic variation--has traditionally been a…

  5. America's Anti-Evolution Movement

    ERIC Educational Resources Information Center

    Moore, Randy

    2002-01-01

    Evolution is the cornerstone of biology and one of the most powerful, exciting, and well-supported laws in modern science. Evolution transforms biology from a collection of unrelated observations and definitions into a coherent discipline that, among other things, helps people understand life's history and predict answers to important research…

  6. Evolution: Understanding Life on Earth.

    ERIC Educational Resources Information Center

    Dybas, Cheryl Lyn

    2002-01-01

    Reports on presentations representing evolution at the 53rd annual meeting of the American Institute of Biological Sciences (AIBS) which was held March 22-24, 2002. Explains evolutionary patterns, phylogenetic pageantry, molecular clocks, speciation and biogeography, speciation and macroevolution, and human-induced evolution of drugs-resistant…

  7. Evolution in Schools: Where's Canada?

    ERIC Educational Resources Information Center

    Wiles, Jason R.

    2006-01-01

    Recent events in the United States have brought anti-evolution efforts into the forefront of the media's coverage of science education, and it makes press in Canadian outlets as well. Canadians can be regularly heard scoffing at American debacles such as the controversy regarding the denigration of evolution in Kansas's science standards, the…

  8. Evolution in Schools: Where's Canada?

    ERIC Educational Resources Information Center

    Wiles, Jason R.

    2006-01-01

    Recent events in the United States have brought anti-evolution efforts into the forefront of the media's coverage of science education, and it makes press in Canadian outlets as well. Canadians can be regularly heard scoffing at American debacles such as the controversy regarding the denigration of evolution in Kansas's science standards, the…

  9. Student Visual Communication of Evolution

    ERIC Educational Resources Information Center

    Oliveira, Alandeom W.; Cook, Kristin

    2017-01-01

    Despite growing recognition of the importance of visual representations to science education, previous research has given attention mostly to verbal modalities of evolution instruction. Visual aspects of classroom learning of evolution are yet to be systematically examined by science educators. The present study attends to this issue by exploring…

  10. Major transitions in human evolution.

    PubMed

    Foley, Robert A; Martin, Lawrence; Mirazón Lahr, Marta; Stringer, Chris

    2016-07-05

    Evolutionary problems are often considered in terms of 'origins', and research in human evolution seen as a search for human origins. However, evolution, including human evolution, is a process of transitions from one state to another, and so questions are best put in terms of understanding the nature of those transitions. This paper discusses how the contributions to the themed issue 'Major transitions in human evolution' throw light on the pattern of change in hominin evolution. Four questions are addressed: (1) Is there a major divide between early (australopithecine) and later (Homo) evolution? (2) Does the pattern of change fit a model of short transformations, or gradual evolution? (3) Why is the role of Africa so prominent? (4) How are different aspects of adaptation-genes, phenotypes and behaviour-integrated across the transitions? The importance of developing technologies and approaches and the enduring role of fieldwork are emphasized.This article is part of the themed issue 'Major transitions in human evolution'. © 2016 The Author(s).

  11. The Molecular Basis of Evolution.

    ERIC Educational Resources Information Center

    Wilson, Allan C.

    1985-01-01

    Discovery that mutations accumulate at steady rates over time in the genes of all lineages of plants and animals has led to new insights into evolution at the molecular and organismal levels. Discusses molecular evolution, examining deoxyribonuclei acid (DNA) sequences, morphological distances, and codon rate of change. (DH)

  12. A Teaching Guide to Evolution

    ERIC Educational Resources Information Center

    Gregg, Thomas G.; Janssen, Gary R.; Bhattacharjee, J.K.

    2003-01-01

    Evolution is considered by virtually all biologists to be the central unifying principle of biology, yet its fundamental concepts are not widely understood or widely disseminated. Teaching evolution--defined as descent with modification from a common ancestor as a result of natural selection acting on genetic variation--has traditionally been a…

  13. The Molecular Basis of Evolution.

    ERIC Educational Resources Information Center

    Wilson, Allan C.

    1985-01-01

    Discovery that mutations accumulate at steady rates over time in the genes of all lineages of plants and animals has led to new insights into evolution at the molecular and organismal levels. Discusses molecular evolution, examining deoxyribonuclei acid (DNA) sequences, morphological distances, and codon rate of change. (DH)

  14. Evolution & the Cesarean Section Rate

    ERIC Educational Resources Information Center

    Walsh, Joseph A.

    2008-01-01

    "Nothing in biology makes sense except in the light of evolution." This was the title of an essay by geneticist Theodosius Dobzhansky writing in 1973. Many causes have been given for the increased Cesarean section rate in developed countries, but biologic evolution has not been one of them. The C-section rate will continue to rise, because the…

  15. Evolution: Understanding Life on Earth.

    ERIC Educational Resources Information Center

    Dybas, Cheryl Lyn

    2002-01-01

    Reports on presentations representing evolution at the 53rd annual meeting of the American Institute of Biological Sciences (AIBS) which was held March 22-24, 2002. Explains evolutionary patterns, phylogenetic pageantry, molecular clocks, speciation and biogeography, speciation and macroevolution, and human-induced evolution of drugs-resistant…

  16. Cultural evolution need not imply group selection.

    PubMed

    Amir, Dorsa; Jordan, Matthew R; Rand, David G

    2016-01-01

    Richerson et al. make a compelling case for cultural evolution. In focusing on cultural group selection, however, they neglect important individual-level accounts of cultural evolution. While scientific discourse typically links cultural evolution to group selection and genetic evolution to individual selection, this association is due to historical accident only. We thus call for more consideration of individual-level cultural evolution.

  17. The Fact and the Theory of Evolution.

    ERIC Educational Resources Information Center

    Hughes, Stuart W.

    1982-01-01

    Debates the issue of evolution v creationism, focusing on evolution as fact or theory. Concludes that eminent scientific authorities consider evolution a fact and demonstrates that, in spite of this, writers of college and secondary textbooks refer to evolution as theory. Supports teaching of evolution, not creationism, in science classes. (DC)

  18. Divergent evolution of life span associated with mitochondrial DNA evolution.

    PubMed

    Stojković, Biljana; Sayadi, Ahmed; Đorđević, Mirko; Jović, Jelena; Savković, Uroš; Arnqvist, Göran

    2017-01-01

    Mitochondria play a key role in ageing. The pursuit of genes that regulate variation in life span and ageing have shown that several nuclear-encoded mitochondrial genes are important. However, the role of mitochondrial encoded genes (mtDNA) is more controversial and our appreciation of the role of mtDNA for the evolution of life span is limited. We use replicated lines of seed beetles that have been artificially selected for long or short life for >190 generations, now showing dramatic phenotypic differences, to test for a possible role of mtDNA in the divergent evolution of ageing and life span. We show that these divergent selection regimes led to the evolution of significantly different mtDNA haplotype frequencies. Selection for a long life and late reproduction generated positive selection for one specific haplotype, which was fixed in most such lines. In contrast, selection for reproduction early in life led to both positive selection as well as negative frequency-dependent selection on two different haplotypes, which were both present in all such lines. Our findings suggest that the evolution of life span was in part mediated by mtDNA, providing support for the emerging general tenet that adaptive evolution of life-history syndromes may involve mtDNA. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  19. Evolution of Genome Architecture

    PubMed Central

    Koonin, Eugene V.

    2012-01-01

    Charles Darwin believed that all traits of organisms have been honed to near perfection by natural selection. The empirical basis underlying Darwin’s conclusions consisted of numerous observations made by him and other naturalists on the exquisite adaptations of animals and plants to their natural habitats and on the impressive results of artificial selection. Darwin fully appreciated the importance of heredity but was unaware of the nature and, in fact, the very existence of genomes. A century and a half after the publication of the “Origin”, we have the opportunity to draw conclusions from the comparisons of hundreds of genome sequences from all walks of life. These comparisons suggest that the dominant mode of genome evolution is quite different from that of the phenotypic evolution. The genomes of vertebrates, those purported paragons of biological perfection, turned out to be veritable junkyards of selfish genetic elements where only a small fraction of the genetic material is dedicated to encoding biologically relevant information. In sharp contrast, genomes of microbes and viruses are incomparably more compact, with most of the genetic material assigned to distinct biological functions. However, even in these genomes, the specific genome organization (gene order) is poorly conserved. The results of comparative genomics lead to the conclusion that the genome architecture is not a straightforward result of continuous adaptation but rather is determined by the balance between the selection pressure, that is itself dependent on the effective population size and mutation rate, the level of recombination, and the activity of selfish elements. Although genes and, in many cases, multigene regions of genomes possess elaborate architectures that ensure regulation of expression, these arrangements are evolutionarily volatile and typically change substantially even on short evolutionary scales when gene sequences diverge minimally. Thus, the observed genome

  20. Evolution of Interstellar Grains

    NASA Technical Reports Server (NTRS)

    Allamandola, Lou J.; DeVincenzi, Donald L. (Technical Monitor)

    1998-01-01

    During the past two decades observations combined with laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the raw materials from which planets, comets and stars form. Most interstellar material is concentrated in large molecular clouds where simple molecules are formed by dust-grain and gas-phase reactions. Gaseous species striking the cold (10K) dust stick, forming an icy grain mantle. This accretion, coupled with UV photolysis, produces a complex chemical mixture containing volatile, non-volatile, and isotopically fractionated species. Ices in molecular clouds contain the very simple molecules H2O, CH3OH, CO, CO2, H2, and perhaps some NH3 and H2CO, as well as more complex species. The evidence for these compounds, as well as carbon-rich materials, will be reviewed and the possible connections with comets and meteorites will be presented in the first part of the talk . The second part of the presentation will focus on interstellar/precometary ice photochemical evolution and the species likely to be found in comets. The chemical composition and photochemical evolution of realistic interstellar/pre-cometary ice analogs will be discussed. Ultraviolet photolysis of these ices produces H2, H2CO, CO2, CO, CH4, HCO, and more complex molecules. When ices representative of interstellar grains and comets are exposed to UV radiation at low temperature a series of moderately complex organic molecules are formed in the ice including: CH3CH2OH (ethanol), HC(=O)NH2 (formamide), CH3C(=O)NH2 (acetamide), and R-C=N (nitriles). Several of these are already known to be in the interstellar medium, and their presence indicates the importance of grain processing. After warming to room temperature an organic residue remains. This is composed primarily of hexamethylenetetramine (HMT, C6H12N4), with lesser amounts of polyoxymethylene-related species (POMs), amides, and ketones. This is in sharp contrast to the organic residues produced by

  1. Lakes, Lagerstaetten, and Evolution

    NASA Astrophysics Data System (ADS)

    Kordesch, E. G.; Park, L. E.

    2001-12-01

    nonmarine organisms, and thus the evolution of freshwater organisms, can occur in a short geologic timespan. Because of their unique and varied conditions, the evolution of nonmarine organisms may be linked to lake basin type as well as lake longevity.

  2. Evolution of the Insects

    NASA Astrophysics Data System (ADS)

    Grimaldi, David; Engel, Michael S.

    2005-05-01

    This book chronicles the complete evolutionary history of insects--their living diversity and relationships as well as 400 million years of fossils. Introductory sections cover the living species diversity of insects, methods of reconstructing evolutionary relationships, basic insect structure, and the diverse modes of insect fossilization and major fossil deposits. Major sections then explore the relationships and evolution of each order of hexapods. The volume also chronicles major episodes in the evolutionary history of insects from their modest beginnings in the Devonian and the origin of wings hundreds of millions of years before pterosaurs and birds to the impact of mass extinctions and the explosive radiation of angiosperms on insects, and how they evolved into the most complex societies in nature. Whereas other volumes focus on either living species or fossils, this is the first comprehensive synthesis of all aspects of insect evolution. Illustrated with 955 photo- and electron- micrographs, drawings, diagrams, and field photos, many in full color and virtually all of them original, this reference will appeal to anyone engaged with insect diversity--professional entomologists and students, insect and fossil collectors, and naturalists. David Grimaldi and Michael S. Engel have collectively published over 200 scientific articles and monographs on the relationships and fossil record of insects, including 10 articles in the journals Science, Nature, and Proceedings of the National Academy of Sciences. David Grimaldi is curator in the Division of Invertebrate Zoology, American Museum of Natural History and adjunct professor at Cornell University, Columbia University, and the City University of New York. David Grimaldi has traveled in 40 countries on 6 continents, collecting and studying recent species of insects and conducting fossil excavations. He is the author of Amber: Window to the Past (Abrams, 2003). Michael S. Engel is an assistant professor in the

  3. Evolution of Interstellar Grains

    NASA Technical Reports Server (NTRS)

    Allamandola, Lou J.; DeVincenzi, Donald L. (Technical Monitor)

    1998-01-01

    During the past two decades observations combined with laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the raw materials from which planets, comets and stars form. Most interstellar material is concentrated in large molecular clouds where simple molecules are formed by dust-grain and gas-phase reactions. Gaseous species striking the cold (10K) dust stick, forming an icy grain mantle. This accretion, coupled with UV photolysis, produces a complex chemical mixture containing volatile, non-volatile, and isotopically fractionated species. Ices in molecular clouds contain the very simple molecules H2O, CH3OH, CO, CO2, H2, and perhaps some NH3 and H2CO, as well as more complex species. The evidence for these compounds, as well as carbon-rich materials, will be reviewed and the possible connections with comets and meteorites will be presented in the first part of the talk . The second part of the presentation will focus on interstellar/precometary ice photochemical evolution and the species likely to be found in comets. The chemical composition and photochemical evolution of realistic interstellar/pre-cometary ice analogs will be discussed. Ultraviolet photolysis of these ices produces H2, H2CO, CO2, CO, CH4, HCO, and more complex molecules. When ices representative of interstellar grains and comets are exposed to UV radiation at low temperature a series of moderately complex organic molecules are formed in the ice including: CH3CH2OH (ethanol), HC(=O)NH2 (formamide), CH3C(=O)NH2 (acetamide), and R-C=N (nitriles). Several of these are already known to be in the interstellar medium, and their presence indicates the importance of grain processing. After warming to room temperature an organic residue remains. This is composed primarily of hexamethylenetetramine (HMT, C6H12N4), with lesser amounts of polyoxymethylene-related species (POMs), amides, and ketones. This is in sharp contrast to the organic residues produced by

  4. Evolution, Creation, and the Scientific Method

    ERIC Educational Resources Information Center

    Moore, John N.

    1973-01-01

    Doubts about the validity of the general theory of evolution are raised. Evidence in favor of evolution is circumstantial and not reproducible. Teachers should explain the theory of creation proposed in the Bible when discussing evolution. (PS)

  5. Extraterrestrial civilizations: Problems of their evolution

    NASA Technical Reports Server (NTRS)

    Leskov, L. V.

    1987-01-01

    The problem of finding extraterrestrial civilizations and establishing contact with them is directly related to the problem of their evolution. Possible patterns in this evolution and the stages in the evolution of extraterrestrial civilizations are examined.

  6. Evolution of Cyclodextrin Nanosponges.

    PubMed

    Caldera, Fabrizio; Tannous, Maria; Cavalli, Roberta; Zanetti, Marco; Trotta, Francesco

    2017-10-15

    Cyclodextrin-based nanosponges (CD-NSs) are insoluble, highly cross-linked 3D network polymers used in several scientific and technological fields, the main area of investigation concerns the pharmaceutical applications, in which CD-NSs have been mostly employed as drug delivery systems. CD-NSs can be generally grouped into four consecutive generations, taking into account their chemical composition and properties. The 1st generation of NSs are plain nanosponges, subdivided into four main types: urethane, carbonate, ester and ether NSs, depending on the chemical nature of the functional group connecting the CD to the cross-linker. The 2nd generation of NSs are modified nanosponges characterized by specific properties, such as fluorescence and electric charge. The 3rd generation of NSs is represented by stimuli-responsive CD polymers, which are able to modulate their behavior according to external variations in the environment, such as pH and temperature gradients, oxidative/reducing conditions, and finally the 4th generation of NSs, a new family of molecularly imprinted CD polymers (MIPs), exhibiting a high selectivity towards specific molecules. The following review focuses on the evolution of cyclodextrin nanosponges, listing some examples of each generation. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Landscape evolution (A Review)

    PubMed Central

    Sharp, Robert P.

    1982-01-01

    Landscapes are created by exogenic and endogenic processes acting along the interface between the lithosphere and the atmosphere and hydrosphere. Various landforms result from the attack of weathering and erosion upon the highly heterogeneous lithospheric surface. Landscapes are dynamic, acutely sensitive to natural and artificial perturbation. Undisturbed, they can evolve through a succession of stages to a plain of low relief. Often, the progression of an erosion cycle is interrupted by tectonic or environmental changes; thus, many landscapes preserve vestiges of earlier cycles useful in reconstructing the recent history of Earth's surface. Landforms are bounded by slopes, so their evolution is best understood through study of slopes and the complex of factors controlling slope character and development. The substrate, biosphere, climatic environment, and erosive processes are principal factors. Creep of the disintegrated substrate and surface wash by water are preeminent. Some slopes attain a quasisteady form and recede parallel to themselves (backwearing); others become ever gentler with time (downwearing). The lovely convex/rectilinear/concave profile of many debris-mantled slopes reflects an interplay between creep and surface wash. Landscapes of greatest scenic attraction are usually those in which one or two genetic factors have strongly dominated or those perturbed by special events. Nature has been perturbing landscapes for billions of years, so mankind can learn about landscape perturbation from natural examples. Images

  8. EVOLUTION OF MYELOID CELLS

    PubMed Central

    Barreda, Daniel R.; Neely, Harold R.; Flajnik, Martin F.

    2015-01-01

    In 1882, Elie Metchnikoff identified myeloid-like cells from starfish larvae responding to the invasion by a foreign body (rose thorn). This marked the origins of the study of innate immunity, and an appreciation that cellular immunity is already well established in these “primitive” organisms. This chapter focuses on these myeloid cells as well as the newest members of this family, the dendritic cells (DC), and explores their evolutionary origins. Our goal is to provide evolutionary context for the development of the multilayered immune system of mammals, where myeloid cells now serve as central effectors of innate immunity and regulators of adaptive immunity. Overall, we find that core contributions of myeloid cells to the regulation of inflammation are based on mechanisms that have been honed over hundreds of millions of years of evolution. Using phagocytosis as a platform, we show how fairly simple beginnings have offered a robust foundation onto which additional control features have been integrated, resulting in central regulatory nodes that now manage multi-factorial aspects of homeostasis and immunity. PMID:27337471

  9. Mercury's core evolution

    NASA Astrophysics Data System (ADS)

    Deproost, Marie-Hélène; Rivoldini, Attilio; Van Hoolst, Tim

    2016-10-01

    Remote sensing data of Mercury's surface by MESSENGER indicate that Mercury formed under reducing conditions. As a consequence, silicon is likely the main light element in the core together with a possible small fraction of sulfur. Compared to sulfur, which does almost not partition into solid iron at Mercury's core conditions and strongly decreases the melting temperature, silicon partitions almost equally well between solid and liquid iron and is not very effective at reducing the melting temperature of iron. Silicon as the major light element constituent instead of sulfur therefore implies a significantly higher core liquidus temperature and a decrease in the vigor of compositional convection generated by the release of light elements upon inner core formation.Due to the immiscibility in liquid Fe-Si-S at low pressure (below 15 GPa), the core might also not be homogeneous and consist of an inner S-poor Fe-Si core below a thinner Si-poor Fe-S layer. Here, we study the consequences of a silicon-rich core and the effect of the blanketing Fe-S layer on the thermal evolution of Mercury's core and on the generation of a magnetic field.

  10. Freud and evolution.

    PubMed

    Scharbert, Gerhard

    2009-01-01

    The essay analyzes the influence of evolutionary thought in the work of Sigmund Freud. Based on Freud's initial occupation as a neuro-anatomist and physiologist certain aspects stemming from the history of nature and developmental biological reasoning that played a role in his endeavours to find a new basis for medical psychology will be pointed out. These considerations are to be regarded as prolegomena of the task to reread Freud once again, and in doing so avoiding the verdict that holds his neuro-anatomic and comparative-morphological works as simply "pre-analytic." In fact, the time seems ripe to reconsider in a new context particularly those evolutionary, medical, and cultural-scientific elements in Freud's work that appear inconsistent at first sight. The substantial thesis is that Freud, given the fact that he was trained in comparative anatomy and physiology in the tradition of Johannes Müller, had the capability of synthesizing elements of this new point of view with the findings and interrogations concerning developmental history and the theory of evolution. More over, this was perceived not merely metaphoric, as he himself stressed it (Freud 1999, XIII, 99), but in the sense of Ubertragung, that inscribed terms and methods deriving from the given field into the realm of psychology. The moving force behind this particular Ubertragung came from a dynamically-neurological perception of the soul that emerged in France since 1800, which Freud came to know trough the late work of Charcot.

  11. Reconstructing recent human evolution.

    PubMed

    Stringer, C B

    1992-08-29

    The two most distinct models of recent human evolution, the multiregional and the recent African origin models, have different retrodictions concerning specific archaic-recent population relationships. The former model infers multiple regional archaic-modern connections and the ancient establishment of regional characteristics, whereas the latter model implies only an African archaic-all modern relationship, with recent (late Pleistocene) development of regionality. In this paper, four late archaic groups from Europe, southwest Asia, Africa and East Asia are compared with various fossil and recent Homo sapiens crania or cranial samples. The results of Penrose shape comparisons narrowly favour a late archaic African-modern special relationship over an East Asian-modern one, with European and southwest Asian Neanderthal groups much more distant. No specific archaic-recent regional relationships are indicated in the shape analyses, nor in separate examinations of patterns of regionality, which indicate a recent origin for present day regionality. The Skhul-Qafzeh sample provides an excellent shape intermediate between the archaic and recent samples.

  12. Thermodynamics and evolution.

    PubMed

    Demetrius, L

    2000-09-07

    The science of thermodynamics is concerned with understanding the properties of inanimate matter in so far as they are determined by changes in temperature. The Second Law asserts that in irreversible processes there is a uni-directional increase in thermodynamic entropy, a measure of the degree of uncertainty in the thermal energy state of a randomly chosen particle in the aggregate. The science of evolution is concerned with understanding the properties of populations of living matter in so far as they are regulated by changes in generation time. Directionality theory, a mathematical model of the evolutionary process, establishes that in populations subject to bounded growth constraints, there is a uni-directional increase in evolutionary entropy, a measure of the degree of uncertainty in the age of the immediate ancestor of a randomly chosen newborn. This article reviews the mathematical basis of directionality theory and analyses the relation between directionality theory and statistical thermodynamics. We exploit an analytic relation between temperature, and generation time, to show that the directionality principle for evolutionary entropy is a non-equilibrium extension of the principle of a uni-directional increase of thermodynamic entropy. The analytic relation between these directionality principles is consistent with the hypothesis of the equivalence of fundamental laws as one moves up the hierarchy, from a molecular ensemble where the thermodynamic laws apply, to a population of replicating entities (molecules, cells, higher organisms), where evolutionary principles prevail.

  13. Evolution of Replication Machines

    PubMed Central

    Yao, Nina Y.; O'Donnell, Mike E.

    2016-01-01

    The machines that decode and regulate genetic information require the translation, transcription and replication pathways essential to all living cells. Thus, it might be expected that all cells share the same basic machinery for these pathways that were inherited from the primordial ancestor cell from which they evolved. A clear example of this is found in the translation machinery that converts RNA sequence to protein. The translation process requires numerous structural and catalytic RNAs and proteins, the central factors of which are homologous in all three domains of life, bacteria, archaea and eukarya. Likewise, the central actor in transcription, RNA polymerase, shows homology among the catalytic subunits in bacteria, archaea and eukarya. In contrast, while some “gears” of the genome replication machinery are homologous in all domains of life, most components of the replication machine appear to be unrelated between bacteria and those of archaea and eukarya. This review will compare and contrast the central proteins of the “replisome” machines that duplicate DNA in bacteria, archaea and eukarya, with an eye to understanding the issues surrounding the evolution of the DNA replication apparatus. PMID:27160337

  14. Nanosciences: Evolution or revolution?

    NASA Astrophysics Data System (ADS)

    Pautrat, Jean-Louis

    2011-09-01

    In miniaturized objects fabricated by modern technology the smallest linear size may be of a few nanometers. In the field of microelectronics, the advantages of such a miniaturization are huge (increased complexity and reliability, reduced costs). The technology is now approaching the limits where further size reduction will be impossible, except for very novel techniques such as molecular electronics. Miniaturization research has also led to the discovery of nanometric objects such as carbon nanotubes, which turn out to be particularly appropriate for inventing new materials. Miniaturization techniques have been progressively applied in other fields, with the hope of obtaining improvements similar to those encountered in microelectronics. Examples are biochips, which concentrate on a few cm 2 the recognition of ADN sequences, or 'lab-on-a-chip' devices, each of which constitutes a whole laboratory of chemical analysis, or MEMs (Micro Electro Mechanical Systems). New therapies will use miniaturized objects with multiple functions: For instance a nanoparticle can both recognize the target organ thanks to an appropriate protein, and deliver the therapeutic molecule to this target. These results have only been possible through new observation instruments, able to observe and manipulate nano objects. Is the observed evolution really a revolution of science and techniques? This is a point discussed in the conclusion, which also deals with risks associated to nanotechnologies, while the need for a social regulation is stressed.

  15. Organisms in evolution.

    PubMed

    Martens, Johannes

    2010-01-01

    Organisms constitute one of the most remarkable features of our living world. However, they have not yet received any accepted characterization within the framework of the evolutionary theory. The reasons for this contrast between the saliency of organisms in the biological landscape and their theoretical status are multiple and they are analyzed in the first part of this paper. Starting from this contrast, I argue for a theoretically grounded concept of organism within the framework of evolutionary theory itself. To this effect I argue that the theory of major transitions in evolution (Maynard Smith and Szathmáry 1995; Michod 1999) provides us with the theoretical basis for an understanding of the individuality of organisms and I propose a first characterization of organisms as evolutionary units structured by a division of reproductive labor among their parts. I also discuss one of the most important implications of this definition, namely that some colonial entities are to be counted as superorganisms. Finally, I show that though theoretically satisfying, this definition does not suffice in order fully to individuate the organisms and superorganisms in practice. To this end, physiology is needed, because it offers us some criteria for their individuation in ecological space. These criteria, however, are not immune to errors through misidentification and their shortcomings are discussed in the last section. In conclusion, I emphasize the positive implications of these criteria concerning the ecological significance of organisms.

  16. Monitoring Evolution at CERN

    NASA Astrophysics Data System (ADS)

    Andrade, P.; Fiorini, B.; Murphy, S.; Pigueiras, L.; Santos, M.

    2015-12-01

    Over the past two years, the operation of the CERN Data Centres went through significant changes with the introduction of new mechanisms for hardware procurement, new services for cloud provisioning and configuration management, among other improvements. These changes resulted in an increase of resources being operated in a more dynamic environment. Today, the CERN Data Centres provide over 11000 multi-core processor servers, 130 PB disk servers, 100 PB tape robots, and 150 high performance tape drives. To cope with these developments, an evolution of the data centre monitoring tools was also required. This modernisation was based on a number of guiding rules: sustain the increase of resources, adapt to the new dynamic nature of the data centres, make monitoring data easier to share, give more flexibility to Service Managers on how they publish and consume monitoring metrics and logs, establish a common repository of monitoring data, optimise the handling of monitoring notifications, and replace the previous toolset by new open source technologies with large adoption and community support. This contribution describes how these improvements were delivered, present the architecture and technologies of the new monitoring tools, and review the experience of its production deployment.

  17. Evolution of coalitionary killing.

    PubMed

    Wrangham, R W

    1999-01-01

    Warfare has traditionally been considered unique to humans. It has, therefore, often been explained as deriving from features that are unique to humans, such as the possession of weapons or the adoption of a patriarchal ideology. Mounting evidence suggests, however, that coalitional killing of adults in neighboring groups also occurs regularly in other species, including wolves and chimpanzees. This implies that selection can favor components of intergroup aggression important to human warfare, including lethal raiding. Here I present the principal adaptive hypothesis for explaining the species distribution of intergroup coalitional killing. This is the "imbalance-of-power hypothesis," which suggests that coalitional killing is the expression of a drive for dominance over neighbors. Two conditions are proposed to be both necessary and sufficient to account for coalitional killing of neighbors: (1) a state of intergroup hostility; (2) sufficient imbalances of power between parties that one party can attack the other with impunity. Under these conditions, it is suggested, selection favors the tendency to hunt and kill rivals when the costs are sufficiently low. The imbalance-of-power hypothesis has been criticized on a variety of empirical and theoretical grounds which are discussed. To be further tested, studies of the proximate determinants of aggression are needed. However, current evidence supports the hypothesis that selection has favored a hunt-and-kill propensity in chimpanzees and humans, and that coalitional killing has a long history in the evolution of both species.

  18. Evolution of echocardiography.

    PubMed

    Feigenbaum, H

    1996-04-01

    The evolution of echocardiography has been interesting and dramatic. The technology has grown and has become an integral part of the practice of cardiology. As with all technology, there are advantages and disadvantages. The principal disadvantage is the fact that education and training are imperative to provide high-quality examinations and proper interpretations. In addition, many of the diagnoses are still qualitative and subjective. The principal advantage is the amazing versatility of this technology. The wealth of information that can be provided both noninvasively with a transthoracic examination and invasively with either transesophageal or intravascular ultrasound is tremendous. The anatomic and physiological data provided frequently give definitive diagnoses. If performed properly and for the right reason, this test should be very cost effective and should be a major asset in the coming era of medical cost containment. There are many technological advances that should enhance this information. With technology such as digital recordings, it is hoped that the clinicians will have better access to these data and will be more comfortable in interacting with this important diagnostic tool.

  19. Microfluidic Compartmentalized Directed Evolution

    PubMed Central

    Paegel, Brian M.; Joyce, Gerald F.

    2010-01-01

    Summary Directed evolution studies often make use of water-in-oil compartments, which conventionally are prepared by bulk emulsification, a crude process that generates non-uniform droplets and can damage biochemical reagents. A microfluidic emulsification circuit was devised that generates uniform water-in-oil droplets (21.9 ± 0.8 μm radius) with high throughput (107–108 droplets per hour). The circuit contains a radial array of aqueous flow nozzles that intersect a surrounding oil flow channel. This device was used to evolve RNA enzymes with RNA ligase activity, selecting enzymes that could resist inhibition by neomycin. Each molecule in the population had the opportunity to undergo 108-fold selective amplification within its respective compartment. Then the progeny RNAs were harvested and used to seed new compartments. During five rounds of this procedure, the enzymes acquired mutations that conferred resistance to neomycin and caused some enzymes to become dependent on neomycin for optimal activity. PMID:20659684

  20. The evolution of replicators.

    PubMed

    Szathmáry, E

    2000-11-29

    Replicators of interest in chemistry, biology and culture are briefly surveyed from a conceptual point of view. Systems with limited heredity have only a limited evolutionary potential because the number of available types is too low. Chemical cycles, such as the formose reaction, are holistic replicators since replication is not based on the successive addition of modules. Replicator networks consisting of catalytic molecules (such as reflexively autocatalytic sets of proteins, or reproducing lipid vesicles) are hypothetical ensemble replicators, and their functioning rests on attractors of their dynamics. Ensemble replicators suffer from the paradox of specificity: while their abstract feasibility seems to require a high number of molecular types, the harmful effect of side reactions calls for a small system size. No satisfactory solution to this problem is known. Phenotypic replicators do not pass on their genotypes, only some aspects of the phenotype are transmitted. Phenotypic replicators with limited heredity include genetic membranes, prions and simple memetic systems. Memes in human culture are unlimited hereditary, phenotypic replicators, based on language. The typical path of evolution goes from limited to unlimited heredity, and from attractor-based to modular (digital) replicators.

  1. Geological processes and evolution

    USGS Publications Warehouse

    Head, J.W.; Greeley, R.; Golombek, M.P.; Hartmann, W.K.; Hauber, E.; Jaumann, R.; Masson, P.; Neukum, G.; Nyquist, L.E.; Carr, M.H.

    2001-01-01

    Geological mapping and establishment of stratigraphic relationships provides an overview of geological processes operating on Mars and how they have varied in time and space. Impact craters and basins shaped the crust in earliest history and as their importance declined, evidence of extensive regional volcanism emerged during the Late Noachian. Regional volcanism characterized the Early Hesperian and subsequent to that time, volcanism was largely centered at Tharsis and Elysium, continuing until the recent geological past. The Tharsis region appears to have been largely constructed by the Late Noachian, and represents a series of tectonic and volcanic centers. Globally distributed structural features representing contraction characterize the middle Hesperian. Water-related processes involve the formation of valley networks in the Late Noachian and into the Hesperian, an ice sheet at the south pole in the middle Hesperian, and outflow channels and possible standing bodies of water in the northern lowlands in the Late Hesperian and into the Amazonian. A significant part of the present water budget occurs in the present geologically young polar layered terrains. In order to establish more firmly rates of processes, we stress the need to improve the calibration of the absolute timescale, which today is based on crater count systems with substantial uncertainties, along with a sampling of rocks of unknown provenance. Sample return from carefully chosen stratigraphic units could calibrate the existing timescale and vastly improve our knowledge of Martian evolution.

  2. Evolution of galaxy habitability

    NASA Astrophysics Data System (ADS)

    Gobat, Raphael; Hong, Sungwook E.

    2016-08-01

    We combine a semi-analytic model of galaxy evolution with constraints on circumstellar habitable zones and the distribution of terrestrial planets in order to probe the suitability of galaxies of different mass and type to host habitable planets, and how it evolves with time. We find that the fraction of stars with terrestrial planets in their habitable zone (known as habitability) depends only weakly on galaxy mass, with a maximum around 4 × 1010M⊙. We estimate that 0.7% of all stars in Milky Way-type galaxies to host a terrestrial planet within their habitable zone, consistent with the value derived from Kepler observations. On the other hand, the habitability of passive galaxies is slightly but systematically higher, unless we assume an unrealistically high sensitivity of planets to supernovae. We find that the overall habitability of galaxies has not changed significantly in the last ~8 Gyr, with most of the habitable planets in local disk galaxies having formed ~1.5 Gyr before our own solar system. Finally, we expect that ~1.4 ×109 planets similar to present-day Earth have existed so far in our galaxy.

  3. Evolution of optogenetic microdevices

    PubMed Central

    Kale, Rajas P.; Kouzani, Abbas Z.; Walder, Ken; Berk, Michael; Tye, Susannah J.

    2015-01-01

    Abstract. Implementation of optogenetic techniques is a recent addition to the neuroscientists’ preclinical research arsenal, helping to expose the intricate connectivity of the brain and allowing for on-demand direct modulation of specific neural pathways. Developing an optogenetic system requires thorough investigation of the optogenetic technique and of previously fabricated devices, which this review accommodates. Many experiments utilize bench-top systems that are bulky, expensive, and necessitate tethering to the animal. However, these bench-top systems can make use of power-demanding technologies, such as concurrent electrical recording. Newer portable microdevices and implantable systems carried by freely moving animals are being fabricated that take advantage of wireless energy harvesting to power a system and allow for natural movements that are vital for behavioral testing and analysis. An investigation of the evolution of tethered, portable, and implantable optogenetic microdevices is presented, and an analysis of benefits and detriments of each system, including optical power output, device dimensions, electrode width, and weight is given. Opsins, light sources, and optical fiber coupling are also discussed to optimize device parameters and maximize efficiency from the light source to the fiber, respectively. These attributes are important considerations when designing and developing improved optogenetic microdevices. PMID:26158015

  4. Chaos and Galaxy Evolution

    NASA Astrophysics Data System (ADS)

    Kandrup, H. E.

    2002-09-01

    This talk summarises a combined theoretical and numerical investigation of the role of chaos and transient chaos in time-dependent Hamiltonian systems which aim to model elliptical galaxies. The existence of large amounts of chaos in near-equilibrium configurations is of potential importance because configurations incorporating large numbers of chaotic orbits appear to be substantially more susceptible than nearly integrable systems to various irregularities associated with, e.g., internal substructures, satellite galaxies, and/or the effects of a high density environment. Alternatively, transient chaos, reflecting exponential sensitivity over comparatively short time intervals, can prove important by significantly increasing the overall efficiency of violent relaxation so as to facilitate a more rapid evolution towards a `well-mixed' equilibrium. Completely conclusive `smoking gun' evidence for chaos and chaotic mixing has not yet been obtained, although evidence for the presence of chaos can in principle be extracted from such data sets as provided by the Sloan Digital Sky Survey. Interestingly, however, arguments completely analogous to those applied to self-gravitating systems also suggest the presence of chaos in charged particle beams, a setting which is amenable to controlled experiments.

  5. The evolution of replicators.

    PubMed Central

    Szathmáry, E

    2000-01-01

    Replicators of interest in chemistry, biology and culture are briefly surveyed from a conceptual point of view. Systems with limited heredity have only a limited evolutionary potential because the number of available types is too low. Chemical cycles, such as the formose reaction, are holistic replicators since replication is not based on the successive addition of modules. Replicator networks consisting of catalytic molecules (such as reflexively autocatalytic sets of proteins, or reproducing lipid vesicles) are hypothetical ensemble replicators, and their functioning rests on attractors of their dynamics. Ensemble replicators suffer from the paradox of specificity: while their abstract feasibility seems to require a high number of molecular types, the harmful effect of side reactions calls for a small system size. No satisfactory solution to this problem is known. Phenotypic replicators do not pass on their genotypes, only some aspects of the phenotype are transmitted. Phenotypic replicators with limited heredity include genetic membranes, prions and simple memetic systems. Memes in human culture are unlimited hereditary, phenotypic replicators, based on language. The typical path of evolution goes from limited to unlimited heredity, and from attractor-based to modular (digital) replicators. PMID:11127914

  6. Evolution of fluid therapy.

    PubMed

    Kampmeier, Tim; Rehberg, Sebastian; Ertmer, Christian

    2014-09-01

    The human organism consists of evolutionary conserved mechanisms to prevent death from hypovolaemia. Intravenous fluid therapy to support these mechanisms had first been published about 180 years ago. The present review depicts the evolution of fluid therapy from early, not well-defined solutions up to modern balanced fluids. Notably, evidence accumulates that the most commonly used fluid (i.e. 0.9% saline) has no advantage over balanced solutions, increases the risk of acute kidney injury and should therefore be abandoned. Notably, in published trials, the prognostically important 'golden hours' of shock, where fluid therapy may be essential, have not been adequately addressed. It is therefore unclear whether negative data on colloids in some trials reflect real harm or rather inadequate use. Future studies should focus on optimal protocols for initiation, dosing and discontinuation of fluid therapy in specific disease entities. Moreover, the practice of de-resuscitation after fluid-based haemodynamic stabilization should be further investigated. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Sponsorship in evolution.

    PubMed

    Grant, M K

    1990-09-01

    Sponsorship appears to be evolving from an original model in which the sponsoring religious institute related to its facilities in a manner resembling a family business, to a model of sponsorship akin to a franchise, to a ministerial partnership. Factors leading to this evolution include tremendous changes within the religious institute itself, including decreases in the number of members and financial stability. Changes within healthcare itself--such as greater competition and declining revenues-have forced hospitals to diversify. One result of these developments has been a radical change in the "rules" of the game. Historically independent entities--hospitals, sponsors, physicians--now have to value interdependence and mutuality. In the family-run model the family (sponsor) had special privileges, as though they "owned" the business. When the number of family members dropped below that necessary to govern, administer, and staff the institute's facilities, they began to move away from the family model to the franchise model, which has more open communication, greater input to decision making by non-family members, and a shift in the family's attention from actual operations to oversight and accountability. Eventually, the franchise model began to give way to the ministerial partnership, characterized by mutuality. Both family and others have roles not only in carrying out the mission, but in actually shaping and forming it.

  8. Morphological Evolution of Asteroids

    NASA Astrophysics Data System (ADS)

    Richardson, D. C.

    2003-08-01

    Recent ground- and space-based observations of asteroids have revealed that these bodies are far more complex than once imagined. Surprisingly low bulk densities, giant craters, unusual shapes, non-principal-axis spin states, and satellites are all challenging our understanding of how asteroids form and evolve. Since asteroids are the remnants of the planet building era, understanding their nature improves our understanding of the origin of solar systems in general. I will review some of the more puzzling aspects of asteroid morphology, including the existence of asteroid satellites, and discuss recent theoretical advances aimed at understanding our tiny neighbors. I will show that both theoretical and observational evidence is pointing increasingly to asteroids being fragile assemblages of smaller pieces, called gravitational aggregates. The consequences of such fragmented internal structure on asteroid evolution and hazard mitigation will be discussed. This work has been supported in part by the National Aeronautics and Space Administration under Contract No. NAG511722 issued through the Office of Space Science.

  9. Evolution of the ventricles.

    PubMed

    Victor, S; Nayak, V M; Rajasingh, R

    1999-01-01

    We studied the evolution of ventricles by macroscopic examination of the hearts of marine cartilaginous and bony fish, and by angiocardiography and gross examination of the hearts of air-breathing freshwater fish, frogs, turtles, snakes, and crocodiles. A right-sided, thin-walled ventricular lumen is seen in the fish, frog, turtle, and snake. In fish, there is external symmetry of the ventricle, internal asymmetry, and a thick-walled left ventricle with a small inlet chamber. In animals such as frogs, turtles, and snakes, the left ventricle exists as a small-cavitied contractile sponge. The high pressure generated by this spongy left ventricle, the direction of the jet, the ventriculoarterial orientation, and the bulbar spiral valve in the frog help to separate the systemic and pulmonary circulations. In the crocodile, the right aorta is connected to the left ventricle, and there is a complete interventricular septum and an improved left ventricular lumen when compared with turtles and snakes. The heart is housed in a rigid pericardial cavity in the shark, possibly to protect it from changing underwater pressure. The pericardial cavity in various species permits movements of the heart-which vary depending on the ventriculoarterial orientation and need for the ventricle to generate torque or spin on the ejected blood- that favor run-off into the appropriate arteries and their branches. In the lower species, it is not clear whether the spongy myocardium contributes to myocardial oxygenation. In human beings, spongy myocardium constitutes a rare form of congenital heart disease.

  10. Thioredoxin and evolution

    NASA Technical Reports Server (NTRS)

    Buchanan, B. B.

    1991-01-01

    Comparisons of primary structure have revealed significant homology between the m type thioredoxins of chloroplasts and the thioredoxins from a variety of bacteria. Chloroplast thioredoxin f, by comparison, remains an enigma: certain residues are invariant with those of the other thioredoxins, but a phylogenetic relationship to bacterial or m thioredoxins seems distant. Knowledge of the evolutionary history of thioredoxin f is, nevertheless, of interest because of its role in photosynthesis. Therefore, we have attempted to gain information on the evolutionary history of chloroplast thioredoxin f, as well as m. Our goal was first to establish the utility of thioredoxin as a phylogenetic marker, and, if found suitable, to deduce the evolutionary histories of the chloroplast thioredoxins. To this end, we have constructed phylogenetic (minimal replacement) trees using computer analysis. The results show that the thioredoxins of bacteria and animals fall into distinct phylogenetic groups - the bacterial group resembling that derived from earlier 16s RNA analysis and the animal group showing a cluster consistent with known relationships. The chloroplast thioredoxins show a novel type of phylogenetic arrangement: one m type aligns with its counterpart of eukaryotic algae, cyanobacteria and other bacteria, whereas the second type (f type) tracks with animal thioredoxin. The results give new insight into the evolution of photosynthesis.

  11. Genetics and recent human evolution.

    PubMed

    Templeton, Alan R

    2007-07-01

    Starting with "mitochondrial Eve" in 1987, genetics has played an increasingly important role in studies of the last two million years of human evolution. It initially appeared that genetic data resolved the basic models of recent human evolution in favor of the "out-of-Africa replacement" hypothesis in which anatomically modern humans evolved in Africa about 150,000 years ago, started to spread throughout the world about 100,000 years ago, and subsequently drove to complete genetic extinction (replacement) all other human populations in Eurasia. Unfortunately, many of the genetic studies on recent human evolution have suffered from scientific flaws, including misrepresenting the models of recent human evolution, focusing upon hypothesis compatibility rather than hypothesis testing, committing the ecological fallacy, and failing to consider a broader array of alternative hypotheses. Once these flaws are corrected, there is actually little genetic support for the out-of-Africa replacement hypothesis. Indeed, when genetic data are used in a hypothesis-testing framework, the out-of-Africa replacement hypothesis is strongly rejected. The model of recent human evolution that emerges from a statistical hypothesis-testing framework does not correspond to any of the traditional models of human evolution, but it is compatible with fossil and archaeological data. These studies also reveal that any one gene or DNA region captures only a small part of human evolutionary history, so multilocus studies are essential. As more and more loci became available, genetics will undoubtedly offer additional insights and resolutions of human evolution.

  12. On the evolution of development

    PubMed Central

    Torday, John S.

    2015-01-01

    Perhaps development is more than just morphogenesis. We now recognize that the conceptus expresses epigenetic marks that heritably affect it phenotypically, indicating that the offspring are to some degree genetically autonomous, and that ontogeny and phylogeny may coordinately determine the fate of such marks. This scenario mechanistically links ecology, ontogeny and phylogeny together as an integrated mechanism for evolution for the first time. As a functional example, the Parathyroid Hormone-related Protein (PTHrP) signaling duplicated during the Phanerozoic water-land transition. The PTHrP signaling pathway was critical for the evolution of the skeleton, skin barrier, and lung function, based on experimental evidence, inferring that physiologic stress can profoundly affect adaptation through internal selection, giving seminal insights to how and why vertebrates were able to evolve from water to land. By viewing evolution from its inception in unicellular organisms, driven by competition between pro- and eukaryotes, the emergence of complex biologic traits from the unicellular cell membrane offers a novel way of thinking about the process of evolution from its beginnings, rather than from its consequences as is traditionally done. And by focusing on the epistatic balancing mechanisms for calcium and lipid homeostasis, the evolution of unicellular organisms, driven by competition between pro- and eukaryotes, gave rise to the emergence of complex biologic traits derived from the unicellular plasma lemma, offering a unique way of thinking about the process of evolution. By exploiting the cellular-molecular mechanisms of lung evolution as ontogeny and phylogeny, the sequence of events for the evolution of the skin, kidney and skeleton become more transparent. This novel approach to the evolution question offers equally novel insights to the primacy of the unicellular state, hologenomics and even a priori bioethical decisions. PMID:25729239

  13. Evolution: geometrical and dynamical aspects.

    PubMed

    Freguglia, Paolo; Bazzani, Armando

    2003-01-01

    We develop a possible axiomatic approach to the evolution theory that has been previously discussed in Freguglia [2002]. The axioms synthesize the fundamental ideas of evolution theory and allow a geometrical and dynamical interpretation of the generation law. Using the axioms we derive a simple reaction-diffusion model which introduces the species as self-organized stationary distribution of a finite population and simulates the evolution of a phenotypic character under the effect of an external perturbing action. The dynamical properties of the model are briefly presented using numerical simulations.

  14. NLO evolution of color dipoles

    SciTech Connect

    Ian Balitsky; Giovanni Chirilli

    2008-01-01

    The small-x deep inelastic scattering in the saturation region is governed by the non-linear evolution of Wilson-lines operators. In the leading logarithmic approximation it is given by the BK equation for the evolution of color dipoles. In the next-to-leaing order the BK equation gets contributions from quark and gluon loops as well as from the tree gluon diagrams with quadratic and cubic nonlinearities. We calculate the gluon contribution to small-x evolution of Wilson lines (the quark part was obtained earlier).

  15. Chemical evolution of dense clouds

    NASA Technical Reports Server (NTRS)

    Chapelle, E. W.; Donn, B. D.; Payne, W. A., Jr.; Stief, L. J.

    1973-01-01

    Attention is given to chemical processes which could determine the molecular composition of the cloud during the several stages of its evolution, taking into account thermal reactions at the relatively high interstellar densities expected during the processes. The origin of the observed molecules is discussed together with questions of molecular evolution during collapse of the cloud and the role of organic molecules in planetary chemical evolution. A number of experiments are also considered along with the application of the experimental results to cloud equilibrium problems.

  16. Thermal evolution of cometary nuclei

    NASA Technical Reports Server (NTRS)

    Prialnik, Dina

    1989-01-01

    The long-term thermal evolution in models of comet nuclei is examined. Models of the nucleus surface and interior are discussed and the equations of comet nucleus evolution are analyzed. The thermal evolution of a nucleus in Comet P/Halley's orbit is outlined. The effects of temperature, composition, and orbital parameters on the evolutionary course are examined. Consideration is given to the implications of the assumption that new comets are pristine objects which have undergone little alteration and constitute a source of original solar nebula material.

  17. The Evolution of Cataclysmic Variables

    NASA Astrophysics Data System (ADS)

    Li, Lifang; Zhang, Fenghui; Han, Zhanwen

    2013-02-01

    Using Eggletons code the evolution of cataclysmic variables (CVs) is investigated. CVs might suffer the loss of mass and angular momentum during their evolution, we present the models of CVs with mass loss and angular momentum loss (AML) due to gravitation wave radiation (GR) and/or magnetic braking (MB). It is found that the loss of mass and angular momentum has significant influence on the evolution of CVs, and that the change of the star structure or their atmosphere properties is a possible mechanism which underlies a sudden change in the rate of AML owing to MB.

  18. Genome dynamics during experimental evolution

    PubMed Central

    Barrick, Jeffrey E.; Lenski, Richard E.

    2014-01-01

    Evolutionary changes in organismal traits may occur gradually or suddenly. Until recently, however, there has been little direct information about how phenotypic changes are related to the rate and nature of underlying changes in genotype. Technological advances enabling whole-genome and whole-population sequencing coupled with experiments that watch evolution in action have brought new precision and insights to studies of mutation rates and genome evolution. Here, we discuss the evolutionary forces and ecological processes that govern genome dynamics in various laboratory systems in the context of relevant population genetic theory, and we relate these findings to evolution in natural populations. PMID:24166031

  19. Experimental evolution in budding yeast

    NASA Astrophysics Data System (ADS)

    Murray, Andrew

    2012-02-01

    I will discuss our progress in analyzing evolution in the budding yeast, Saccharomyces cerevisiae. We take two basic approaches. The first is to try and examine quantitative aspects of evolution, for example by determining how the rate of evolution depends on the mutation rate and the population size or asking whether the rate of mutation is uniform throughout the genome. The second is to try to evolve qualitatively novel, cell biologically interesting phenotypes and track the mutations that are responsible for the phenotype. Our efforts include trying to alter cell morphology, evolve multicellularity, and produce a biological oscillator.

  20. Nonlinear Evolution Equations in Banach Spaces.

    DTIC Science & Technology

    relationship to the evolution equation is studied. The results obtained extend several known existence theorems and provide generalized solutions of the evolution equation in more general cases. (Author)

  1. Evolution of rhinology.

    PubMed

    Kaluskar, S K

    2008-06-01

    The study of the nose is as old as civilisation. Various conditions affecting its structure and function has been documented in Edwin Smith Papyrus in hieroglyphic script, an Egyptian writing system of the mid -4th Millennium BC.The major contribution for the complete reconstruction of the nose originated in India by Sushruta in around 600 BC. Writing in Sanskrit in the form of verses he described in detail the technique of total reconstruction, which is still being practiced today as Indian Rhinoplasty. This surgical reconstruction paved the way to modern plastic surgery in Europe and United States in 18th century. Sushruta contributed not only to the plastic surgery of the nose, but described entire philosophy of Head and Neck and other surgery as well. Other notable contributors were Greek physicians, Hippocrate and Galen, and at the birth of the Christianity, Celsus wrote eight books of medical encyclopaedia, which described various conditions affecting nose.Septal and Sinus surgery, in comparison to rhinoplasty did not develop until 17th century. Septal surgery began with total septectomy, sub mucous resection by Killian & Freer in early 20th century and later septoplasty by Cottle in middle of 20th century.Sinus surgery probably originated in Egypt, where instruments were used to remove brain through the ethmoid sinuses as part of the mummification process. In 18th century, empyema of the maxillary sinus was drained through the tooth socket or anterior wall of the sinus, which lead to the evolution of radical procedures of removal of mucous membrane and inferior meatal antrostomy. In the late 20th century, improved understanding of the mucociliary mechanism described by Prof. Messerklinger and Nasal Endoscopy described by Prof. Draf with the development of fibre optics and CT imaging, heralded a new era, which evolved in functional endoscopic sinus surgery. New technology further enhanced the scope of endoscope being used "around and beyond" the nose.

  2. Brucella evolution and taxonomy.

    PubMed

    Moreno, Edgardo; Cloeckaert, Axel; Moriyón, Ignacio

    2002-12-20

    The genus Brucella contains alpha-Proteobacteria adapted to intracellular life within cells of a variety of mammals. Controversy has arisen concerning Brucella internal taxonomy, and it has been proposed that the DNA-DNA hybridization-based genomospecies concept be applied to the genus. According to this view, only one species, Brucella melitensis, should be recognized, and the classical species should be considered as biovars (B. melitensis biovar melitensis; B. melitensis biovar abortus; etc.). However, a critical reappraisal of the species concept, a review of the population structure of bacteria and the analysis of Brucella genetic diversity by methods other than DNA-DNA hybridization show that there are no scientific grounds to apply the genomospecies concept to this genus. On the other hand, an enlarged biological species concept allows the definition of Brucella species that are consistent with molecular analyses and support the taxonomical standing of most classical species. Both the host range as a long-recognized biological criterion and the presence of species-specific markers in outer membrane protein genes and in other genes show that B. melitensis, B. abortus, B. ovis, B. canis and B. neotomae are not mere pathovars (or nomenspecies) but biologically meaningful species. The status of B. suis is, however, less clear. These approaches should be useful to define species for the marine mammal Brucella isolates, as illustrated by the grouping of the isolates from pinnipeds or from cetaceans by omp2 gene analysis. It is shown that a correct Brucella species definition is important to understand the evolution of the genus.

  3. Stratocumulus cloud evolution

    SciTech Connect

    Yang, X.; Rogers, D.P.; Norris, P.M.; Johnson, D.W.; Martin, G.M.

    1994-12-31

    The structure and evolution of the extra-tropical marine atmospheric boundary layer (MABL) depends largely on the variability of stratus and stratocumulus clouds. The typical boundary-layer is capped by a temperature inversion that limits exchange with the free atmosphere. Cloud-top is usually coincident with the base of the inversion. Stratus clouds are generally associated with a well-mixed MABL, whereas daytime observations of stratocumulus-topped boundary-layers indicate that the cloud and subcloud layers are often decoupled due to shortwave radiative heating of the cloud layer. In this case the surface-based mixed layer is separated from the base of the stratocumulus (Sc) by a layer that is stable to dry turbulent mixing. This is sometimes referred to as the transition layer. Often cumulus clouds (Cu) develop in the transition layer. The cumulus tops may remain below the Sc base or they may penetrate into the Sc layer and occasionally through the capping temperature inversion. While this cloud structure is characteristic of the daytime MABL, it may persist at night also. The Cu play an important role in connecting the mixed layer to the Sc layer. If the Cu are active they transport water vapor from the sea surface that maintains the Sc against the dissipating effects of shortwave heating. The Cu, however, are very sensitive to small changes in the heat and moisture in the boundary-layer and are transient features. Here the authors discuss the effect of these small Cu on the turbulent structure of the MABL.

  4. Evolution of clustered supernovae

    NASA Astrophysics Data System (ADS)

    Vasiliev, Evgenii O.; Shchekinov, Yuri A.; Nath, Biman B.

    2017-07-01

    We study the merging and evolution of isolated supernova (SN) remnants in a stellar cluster into a collective superbubble, with the help of 3D hydrodynamic simulations. We particularly focus on the transition stage when the isolated SN remnants gradually combine to form a superbubble. We find that when the SN rate is high (νsn ˜ 10-9 pc-3 yr-1), the merging phase lasts for ˜104 yr, for n = 1-10 cm-3, and the merging phase lasts for a longer time (˜0.1 Myr or more) for lower SN rates (νsn ≤ 10-10 pc-3 yr-1). During this transition phase, the growing superbubble is filled with dense and cool fragments of shells, and most of the energy is radiated away during this merging process. After passing through the intermediate phase, the superbubble eventually settles on to a new power-law wind asymptote that is smaller than estimated in a continuous wind model. This results in a significant (more than several times) underestimation of the mechanical luminosity needed to feed the bubble. We determine the X-ray and H α surface brightnesses as functions of time for such merging SNe in a stellar cluster and find that clusters with high SN rate shine predominantly in soft X-rays and H α. In particular, a low value of the volume-averaged H α-to-H β ratio and its large spread can be a good indicator of the transition phase of merging SNe.

  5. Fire Control and Human Evolution.

    ERIC Educational Resources Information Center

    Russell, Claire

    1978-01-01

    Briefly outlines some aspects of the discovery of fire control by primitive people, such as the preadaptation for speech, the evolution of the human brain, and natural selection for human nakedness or loss of hair. (CS)

  6. Tracking Tumor Evolution through Mathematics.

    PubMed

    Leslie, Mitch

    2016-04-01

    A recent study suggests that many cancers undergo neutral evolution, with all key mutations present at the start of malignancy. New mutations acquired along the way don't confer any advantages on tumor cells.

  7. EVOLUTION OF SYMPTOMS OF MANIA

    PubMed Central

    Kumar, Ratenendra; Ram, Daya

    2001-01-01

    Mania has been known to result in undesirable consequences like illegitimate pregnancies, financial losses and ruined carriers. An early identification of the syndrome should result in early diagnosis and treatment and limit these undesirable consequences. This study was thus carried out to study the evolution of the manic episode and the factors influencing it. The guardians of 98 consecutive drug free manic patients were given a symptom check list and asked to rate the symptoms in the order of appearance and the duration of each symptom. It was found that there were no consistent patterns of evolution. The median duration of evolution was 45 days. Females and patients with life events had a shorter evolution period. PMID:21407861

  8. Weak interactions and presupernova evolution

    SciTech Connect

    Aufderheide, M.B. State Univ. of New York . Dept. of Physics)

    1991-02-19

    The role of weak interactions, particularly electron capture and {beta}{sup {minus}} decay, in presupernova evolution is discussed. The present uncertainty in these rates is examined and the possibility of improving the situation is addressed. 12 refs., 4 figs.

  9. Evolution, Fundamentalism, and American Education.

    ERIC Educational Resources Information Center

    Doyle, James J.

    1988-01-01

    Describes four court cases involving confrontation between the theory of evolution and the theory of creation: the Scopes trial, the Seagraves trial, Arkansas Act 590, and the Louisiana law. Provides 64 references on the issue. (YP)

  10. Evolution of the Solar System

    NASA Technical Reports Server (NTRS)

    Alfven, H.; Arrhenius, G.

    1976-01-01

    The origin and evolution of the solar system are analyzed. Physical processes are first discussed, followed by experimental studies of plasma-solid reactions and chemical and mineralogical analyses of meteorites and lunar and terrestrial samples.

  11. [The genetic walk of evolution].

    PubMed

    Arnoult, Laurent Angelo

    2014-01-01

    Genetic mutations are the main fuel of evolution. In each generation, they produce new variations, which may be sorted out by natural or sexual selection. Mutations are generated by chance; yet which are the mutations actually sorted out by evolution, and why? This review presents some recent advances regarding this question. First, we gather results obtained at molecular and cellular levels, through synthetic experiments and under artificial selection paradigms. Next, we highlight studies at the multi-cellular level, especially studies of repeated evolution, whereby independent lineages acquire similar traits. Recent meta-analysis and quantifications are being presented; together they suggest that evolutionary relevant mutations accumulate around hotspots, spanning different levels of genetic organization. Pioneering work suggests that many causes, corresponding to many biological contexts, may explain the existence of these genetic hotspots. We finally discuss methodological limits, empirical challenges and a few future potential directions for this domain of research dedicated to the genetic path of evolution.

  12. Thermal evolution of Titan's atmosphere

    SciTech Connect

    Lunine, J.I.; Rizk, B. )

    1989-08-01

    The present model of Titan's atmosphere/surface evolution assumes the presence of a kilometer-deep ethane-methane ocean at the surface that serves as a tropospheric thermal balance-determining atmospheric-gas reservoir. The evolution of the atmospheric thermal structure is driven by gas-abundance changes occurring as stratospheric photolysis irreversibly converts methane into higher hydrocarbons, whereby the ocean becomes ethane-enriched and methane-depleted. A family of evolution models is presented whose various members correspond to different present-day ocean compositions, various atmospheric hydrogen abundances, and different schemes for frequency-averaging the gas opacity. A slow evolution over several billion years is envisioned. 25 refs.

  13. Giant lobelias exemplify convergent evolution.

    PubMed

    Givnish, Thomas J

    2010-01-14

    Giant lobeliads on tropical mountains in East Africa and Hawaii have highly unusual, giant-rosette growth forms that appear to be convergent on each other and on those of several independently evolved groups of Asteraceae and other families. A recent phylogenetic analysis by Antonelli, based on sequencing the widest selection of lobeliads to date, raises doubts about this paradigmatic example of convergent evolution. Here I address the kinds of evidence needed to test for convergent evolution and argue that the analysis by Antonelli fails on four points. Antonelli's analysis makes several important contributions to our understanding of lobeliad evolution and geographic spread, but his claim regarding convergence appears to be invalid. Giant lobeliads in Hawaii and Africa represent paradigmatic examples of convergent evolution.

  14. Plate tectonics: Crustal recycling evolution

    NASA Astrophysics Data System (ADS)

    Magni, Valentina

    2017-09-01

    The processes that form and recycle continental crust have changed through time. Numerical models reveal an evolution from extensive recycling on early Earth as the lower crust peeled away, to limited recycling via slab break-off today.

  15. The Evolution of Complex Life

    NASA Technical Reports Server (NTRS)

    Billingham, John

    1989-01-01

    In considering the probabilities that intelligent life might exist elsewhere in the Universe, it is important to ask questions about the factors governing the emergence of complex living organisms in the context of evolutionary biology, planetary environments and events in space. Two important problems arise. First, what can be learned about the general laws governing the evolution of complex life anywhere in space by studying its history on the Earth? Second, how is the evolution of complex life affected by events in space? To address these problems, a series of Science Workshops on the Evolution of Complex Life was held at the Ames Research Center. Included in this paper are highlights of those workshops, with particular emphasis on the first question, namely the evolution of complex extraterrestrial life.

  16. Linguistics: evolution and language change.

    PubMed

    Bowern, Claire

    2015-01-05

    Linguists have long identified sound changes that occur in parallel. Now novel research shows how Bayesian modeling can capture complex concerted changes, revealing how evolution of sounds proceeds. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Marine microbiology: Evolution on acid

    NASA Astrophysics Data System (ADS)

    Collins, Sinéad

    2012-05-01

    The prediction of marine microbial responses to ocean acidification is a key challenge for marine biologists. Experimental evolution offers a powerful tool for understanding the forces that will shape tomorrow's microbial communities under global change.

  18. Giant lobelias exemplify convergent evolution

    PubMed Central

    2010-01-01

    Giant lobeliads on tropical mountains in East Africa and Hawaii have highly unusual, giant-rosette growth forms that appear to be convergent on each other and on those of several independently evolved groups of Asteraceae and other families. A recent phylogenetic analysis by Antonelli, based on sequencing the widest selection of lobeliads to date, raises doubts about this paradigmatic example of convergent evolution. Here I address the kinds of evidence needed to test for convergent evolution and argue that the analysis by Antonelli fails on four points. Antonelli's analysis makes several important contributions to our understanding of lobeliad evolution and geographic spread, but his claim regarding convergence appears to be invalid. Giant lobeliads in Hawaii and Africa represent paradigmatic examples of convergent evolution. PMID:20074322

  19. Fire Control and Human Evolution.

    ERIC Educational Resources Information Center

    Russell, Claire

    1978-01-01

    Briefly outlines some aspects of the discovery of fire control by primitive people, such as the preadaptation for speech, the evolution of the human brain, and natural selection for human nakedness or loss of hair. (CS)

  20. The evolution of complex life.

    PubMed

    Billingham, J

    1989-01-01

    In considering the probabilities that intelligent life might exist elsewhere in the Universe, it is important to ask questions about the factors governing the emergence of complex living organisms in the context of evolutionary biology, planetary environments and events in space. Two important problems arise. First, what can be learned about the general laws governing the evolution of complex life anywhere in space by studying its history on the Earth? Second, how is the evolution of complex life affected by events in space? To address these problems, a series of Science Workshops on the Evolution of Complex Life was held at the Ames Research Center. Included in this paper are highlights of those workshops, with particular emphasis on the first question, namely the evolution of complex extraterrestrial life.

  1. Chemical Evolution of Protostellar Matter

    NASA Technical Reports Server (NTRS)

    Langer, William D.; vanDishoeck, Ewine F.; Bergin, Edwin A.; Blake, Geoffrey A.; Tielens, Alexander G. G. M.; Velusamy, Thangasamy; Whittet, Douglas C. B.

    2000-01-01

    We review the chemical processes that are important in the evolution from a molecular cloud core to a protostellar disk. These cover both gas phase and gas grain interactions. The current observational and theoretical state of this field are discussed.

  2. Regressive evolution in Astyanax cavefish.

    PubMed

    Jeffery, William R

    2009-01-01

    A diverse group of animals, including members of most major phyla, have adapted to life in the perpetual darkness of caves. These animals are united by the convergence of two regressive phenotypes, loss of eyes and pigmentation. The mechanisms of regressive evolution are poorly understood. The teleost Astyanax mexicanus is of special significance in studies of regressive evolution in cave animals. This species includes an ancestral surface dwelling form and many con-specific cave-dwelling forms, some of which have evolved their recessive phenotypes independently. Recent advances in Astyanax development and genetics have provided new information about how eyes and pigment are lost during cavefish evolution; namely, they have revealed some of the molecular and cellular mechanisms involved in trait modification, the number and identity of the underlying genes and mutations, the molecular basis of parallel evolution, and the evolutionary forces driving adaptation to the cave environment.

  3. Physical Complexity and Cognitive Evolution

    NASA Astrophysics Data System (ADS)

    Jedlicka, Peter

    Our intuition tells us that there is a general trend in the evolution of nature, a trend towards greater complexity. However, there are several definitions of complexity and hence it is difficult to argue for or against the validity of this intuition. Christoph Adami has recently introduced a novel measure called physical complexity that assigns low complexity to both ordered and random systems and high complexity to those in between. Physical complexity measures the amount of information that an organism stores in its genome about the environment in which it evolves. The theory of physical complexity predicts that evolution increases the amount of `knowledge' an organism accumulates about its niche. It might be fruitful to generalize Adami's concept of complexity to the entire evolution (including the evolution of man). Physical complexity fits nicely into the philosophical framework of cognitive biology which considers biological evolution as a progressing process of accumulation of knowledge (as a gradual increase of epistemic complexity). According to this paradigm, evolution is a cognitive `ratchet' that pushes the organisms unidirectionally towards higher complexity. Dynamic environment continually creates problems to be solved. To survive in the environment means to solve the problem, and the solution is an embodied knowledge. Cognitive biology (as well as the theory of physical complexity) uses the concepts of information and entropy and views the evolution from both the information-theoretical and thermodynamical perspective. Concerning humans as conscious beings, it seems necessary to postulate an emergence of a new kind of knowledge - a self-aware and self-referential knowledge. Appearence of selfreflection in evolution indicates that the human brain reached a new qualitative level in the epistemic complexity.

  4. Evolution of ventricular myocyte electrophysiology.

    PubMed

    Rosati, Barbara; Dong, Min; Cheng, Lan; Liou, Shian-Ren; Yan, Qinghong; Park, Ji Young; Shiang, Elaine; Sanguinetti, Michael; Wang, Hong-Sheng; McKinnon, David

    2008-11-12

    The relative importance of regulatory versus structural evolution for the evolution of different biological systems is a subject of controversy. The primacy of regulatory evolution in the diversification of morphological traits has been promoted by many evolutionary developmental biologists. For physiological traits, however, the role of regulatory evolution has received less attention or has been considered to be relatively unimportant. To address this issue for electrophysiological systems, we examined the importance of regulatory and structural evolution in the evolution of the electrophysiological function of cardiac myocytes in mammals. In particular, two related phenomena were studied: the change in action potential morphology in small mammals and the scaling of action potential duration across mammalian phylogeny. In general, the functional properties of the ion channels involved in ventricular action potential repolarization were found to be relatively invariant. In contrast, there were large changes in the expression levels of multiple ion channel and transporter genes. For the Kv2.1 and Kv4.2 potassium channel genes, which are primary determinants of the action potential morphology in small mammals, the functional properties of the proximal promoter regions were found to vary in concordance with species-dependent differences in mRNA expression, suggesting that evolution of cis-regulatory elements is the primary determinant of this trait. Scaling of action potential duration was found to be a complex phenomenon, involving changes in the expression of a large number of channels and transporters. In this case, it is concluded that regulatory evolution is the predominant mechanism by which the scaling is achieved.

  5. Intelsat VII planning and evolution

    NASA Astrophysics Data System (ADS)

    Nadkarni, P.; Neyret, P.; Allnutt, J.; Chidambaram, T.

    This paper describes the evolution of the Intelsat VII concept from among a number of spacecraft concepts considered in the planning process. The considerations of greatest importance in this evolution are examined, including the compatibility with small earth stations, available digital services and circuit multiplication techniques, schedule considerations, launch vehicle considerations, and operational flexibility. The roles of demand analysis and of architecture selection in the development of the Intelsat VII concept are addressed.

  6. Prolegomenon to patterns in evolution.

    PubMed

    Kauffman, Stuart A

    2014-09-01

    Despite Darwin, we remain children of Newton and dream of a grand theory that is epistemologically complete and would allow prediction of the evolution of the biosphere. The main purpose of this article is to show that this dream is false, and bears on studying patterns of evolution. To do so, I must justify the use of the word "function" in biology, when physics has only happenings. The concept of "function" lifts biology irreducibly above physics, for as we shall see, we cannot prestate the ever new biological functions that arise and constitute the very phase space of evolution. Hence, we cannot mathematize the detailed becoming of the biosphere, nor write differential equations for functional variables we do not know ahead of time, nor integrate those equations, so no laws "entail" evolution. The dream of a grand theory fails. In place of entailing laws, I propose a post-entailing law explanatory framework in which Actuals arise in evolution that constitute new boundary conditions that are enabling constraints that create new, typically unprestatable, adjacent possible opportunities for further evolution, in which new Actuals arise, in a persistent becoming. Evolution flows into a typically unprestatable succession of adjacent possibles. Given the concept of function, the concept of functional closure of an organism making a living in its world becomes central. Implications for patterns in evolution include historical reconstruction, and statistical laws such as the distribution of extinction events, or species per genus, and the use of formal cause, not efficient cause, laws. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  7. Protein evolution on rugged landscapes.

    PubMed Central

    Macken, C A; Perelson, A S

    1989-01-01

    We analyze a mathematical model of protein evolution in which the evolutionary process is viewed as hill-climbing on a random fitness landscape. In studying the structure of such landscapes, we note that a large number of local optima exist, and we calculate the time and number of mutational changes until a protein gets trapped at a local optimum. Such a hill-climbing process may underlie the evolution of antibody molecules by somatic hypermutation. PMID:2762321

  8. How Biology Students in Minnesota View Evolution, the Teaching of Evolution and the Evolution-Creationism Controversy

    ERIC Educational Resources Information Center

    Moore, Randy; Froehle, Ann Marie; Kiernan, Julie; Greenwald, Barry

    2006-01-01

    Although most high school students want their biology classes to include evolution, most high school biology classes in Minnesota do not emphasize evolution. This lack of an emphasis on evolution defies state educational standards and is associated with most students (high school and college) having serious misconceptions about evolution. The…

  9. How Biology Students in Minnesota View Evolution, the Teaching of Evolution and the Evolution-Creationism Controversy

    ERIC Educational Resources Information Center

    Moore, Randy; Froehle, Ann Marie; Kiernan, Julie; Greenwald, Barry

    2006-01-01

    Although most high school students want their biology classes to include evolution, most high school biology classes in Minnesota do not emphasize evolution. This lack of an emphasis on evolution defies state educational standards and is associated with most students (high school and college) having serious misconceptions about evolution. The…

  10. Major transitions in human evolution

    PubMed Central

    Foley, Robert A.; Martin, Lawrence; Mirazón Lahr, Marta; Stringer, Chris

    2016-01-01

    Evolutionary problems are often considered in terms of ‘origins', and research in human evolution seen as a search for human origins. However, evolution, including human evolution, is a process of transitions from one state to another, and so questions are best put in terms of understanding the nature of those transitions. This paper discusses how the contributions to the themed issue ‘Major transitions in human evolution’ throw light on the pattern of change in hominin evolution. Four questions are addressed: (1) Is there a major divide between early (australopithecine) and later (Homo) evolution? (2) Does the pattern of change fit a model of short transformations, or gradual evolution? (3) Why is the role of Africa so prominent? (4) How are different aspects of adaptation—genes, phenotypes and behaviour—integrated across the transitions? The importance of developing technologies and approaches and the enduring role of fieldwork are emphasized. This article is part of the themed issue ‘Major transitions in human evolution’. PMID:27298461

  11. The Pace of Cultural Evolution

    PubMed Central

    Perreault, Charles

    2012-01-01

    Today, humans inhabit most of the world’s terrestrial habitats. This observation has been explained by the fact that we possess a secondary inheritance mechanism, culture, in addition to a genetic system. Because it is assumed that cultural evolution occurs faster than biological evolution, humans can adapt to new ecosystems more rapidly than other animals. This assumption, however, has never been tested empirically. Here, I compare rates of change in human technologies to rates of change in animal morphologies. I find that rates of cultural evolution are inversely correlated with the time interval over which they are measured, which is similar to what is known for biological rates. This correlation explains why the pace of cultural evolution appears faster when measured over recent time periods, where time intervals are often shorter. Controlling for the correlation between rates and time intervals, I show that (1) cultural evolution is faster than biological evolution; (2) this effect holds true even when the generation time of species is controlled for; and (3) culture allows us to evolve over short time scales, which are normally accessible only to short-lived species, while at the same time allowing for us to enjoy the benefits of having a long life history. PMID:23024804

  12. Molecular Evolution in Historical Perspective.

    PubMed

    Suárez-Díaz, Edna

    2016-12-01

    In the 1960s, advances in protein chemistry and molecular genetics provided new means for the study of biological evolution. Amino acid sequencing, nucleic acid hybridization, zone gel electrophoresis, and immunochemistry were some of the experimental techniques that brought about new perspectives to the study of the patterns and mechanisms of evolution. New concepts, such as the molecular evolutionary clock, and the discovery of unexpected molecular phenomena, like the presence of repetitive sequences in eukaryotic genomes, eventually led to the realization that evolution might occur at a different pace at the organismic and the molecular levels, and according to different mechanisms. These developments sparked important debates between defendants of the molecular and organismic approaches. The most vocal confrontations focused on the relation between primates and humans, and the neutral theory of molecular evolution. By the 1980s and 1990s, the construction of large protein and DNA sequences databases, and the development of computer-based statistical tools, facilitated the coming together of molecular and evolutionary biology. Although in its contemporary form the field of molecular evolution can be traced back to the last five decades, the field has deep roots in twentieth century experimental life sciences. For historians of science, the origins and consolidation of molecular evolution provide a privileged field for the study of scientific debates, the relation between technological advances and scientific knowledge, and the connection between science and broader social concerns.

  13. The evolution of multicomponent mimicry.

    PubMed

    Franks, Daniel W; Sherratt, Thomas N

    2007-02-21

    The relative sizes of phenotypic mutations contributing to evolutionary change has long been the subject of debate. We describe how mimicry research can shed light on this debate, and frame mimicry studies within the general context of macromutationism and micromutationism, and punctuated versus gradual evolution. Balogh and Leimar [Müllerian mimicry: an examination of Fisher's theory of gradual evolutionary change. Proc. Roy. Soc. Lond. B Biol. Sci. 272, 2269-2275] have recently used a model to readdress the question of whether or not mimicry evolves gradually along a single dimension. We extend their approach, and present the first model to consider the effect of predator generalization along multiple components on the evolution of mimicry. We find that the gradual evolution of mimicry becomes increasingly less likely as the number of signal components increases, unless predators generalize widely over all components. However, we show that the contemporary two-step hypothesis (punctuated evolution followed by gradual refinement) can explain the evolution of Müllerian mimicry under all tested conditions. Thus, although the gradual evolution of mimicry is possible, the two-step hypothesis appears more generally applicable.

  14. Emerging principles of regulatory evolution

    PubMed Central

    Prud'homme, Benjamin; Gompel, Nicolas; Carroll, Sean B.

    2007-01-01

    Understanding the genetic and molecular mechanisms governing the evolution of morphology is a major challenge in biology. Because most animals share a conserved repertoire of body-building and -patterning genes, morphological diversity appears to evolve primarily through changes in the deployment of these genes during development. The complex expression patterns of developmentally regulated genes are typically controlled by numerous independent cis-regulatory elements (CREs). It has been proposed that morphological evolution relies predominantly on changes in the architecture of gene regulatory networks and in particular on functional changes within CREs. Here, we discuss recent experimental studies that support this hypothesis and reveal some unanticipated features of how regulatory evolution occurs. From this growing body of evidence, we identify three key operating principles underlying regulatory evolution, that is, how regulatory evolution: (i) uses available genetic components in the form of preexisting and active transcription factors and CREs to generate novelty; (ii) minimizes the penalty to overall fitness by introducing discrete changes in gene expression; and (iii) allows interactions to arise among any transcription factor and downstream CRE. These principles endow regulatory evolution with a vast creative potential that accounts for both relatively modest morphological differences among closely related species and more profound anatomical divergences among groups at higher taxonomical levels. PMID:17494759

  15. Phylogenomic Insights into Animal Evolution.

    PubMed

    Telford, Maximilian J; Budd, Graham E; Philippe, Hervé

    2015-10-05

    Animals make up only a small fraction of the eukaryotic tree of life, yet, from our vantage point as members of the animal kingdom, the evolution of the bewildering diversity of animal forms is endlessly fascinating. In the century following the publication of Darwin's Origin of Species, hypotheses regarding the evolution of the major branches of the animal kingdom - their relationships to each other and the evolution of their body plans - was based on a consideration of the morphological and developmental characteristics of the different animal groups. This morphology-based approach had many successes but important aspects of the evolutionary tree remained disputed. In the past three decades, molecular data, most obviously primary sequences of DNA and proteins, have provided an estimate of animal phylogeny largely independent of the morphological evolution we would ultimately like to understand. The molecular tree that has evolved over the past three decades has drastically altered our view of animal phylogeny and many aspects of the tree are no longer contentious. The focus of molecular studies on relationships between animal groups means, however, that the discipline has become somewhat divorced from the underlying biology and from the morphological characteristics whose evolution we aim to understand. Here, we consider what we currently know of animal phylogeny; what aspects we are still uncertain about and what our improved understanding of animal phylogeny can tell us about the evolution of the great diversity of animal life.

  16. The pace of cultural evolution.

    PubMed

    Perreault, Charles

    2012-01-01

    Today, humans inhabit most of the world's terrestrial habitats. This observation has been explained by the fact that we possess a secondary inheritance mechanism, culture, in addition to a genetic system. Because it is assumed that cultural evolution occurs faster than biological evolution, humans can adapt to new ecosystems more rapidly than other animals. This assumption, however, has never been tested empirically. Here, I compare rates of change in human technologies to rates of change in animal morphologies. I find that rates of cultural evolution are inversely correlated with the time interval over which they are measured, which is similar to what is known for biological rates. This correlation explains why the pace of cultural evolution appears faster when measured over recent time periods, where time intervals are often shorter. Controlling for the correlation between rates and time intervals, I show that (1) cultural evolution is faster than biological evolution; (2) this effect holds true even when the generation time of species is controlled for; and (3) culture allows us to evolve over short time scales, which are normally accessible only to short-lived species, while at the same time allowing for us to enjoy the benefits of having a long life history.

  17. Mode decomposition evolution equations

    PubMed Central

    Wang, Yang; Wei, Guo-Wei; Yang, Siyang

    2011-01-01

    Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be

  18. Evolution of plant senescence

    PubMed Central

    Thomas, Howard; Huang, Lin; Young, Mike; Ougham, Helen

    2009-01-01

    -related genes allow a framework to be constructed of decisive events in the evolution of the senescence syndrome of modern land-plants. Combining phylogenetic, comparative sequence, gene expression and morphogenetic information leads to the conclusion that biochemical, cellular, integrative and adaptive systems were progressively added to the ancient primary core process of senescence as the evolving plant encountered new environmental and developmental contexts. PMID:19602260

  19. Mode decomposition evolution equations.

    PubMed

    Wang, Yang; Wei, Guo-Wei; Yang, Siyang

    2012-03-01

    Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be

  20. Galactic evolution of Beryllium

    NASA Astrophysics Data System (ADS)

    Boesgaard, Ann Merchant; King, Jeremy R.

    1993-12-01

    The abundance of Be in the lowest-metallicity stars is a probe of Big Bang Nucleosynthesis and its abundance in halo and disk stars is a probe of galactic evolution and stellar structure. We present observations of the Be II resonance lines in 14 halo stars and 27 (mostly old) disk stars with (Fe/H) from -2.7 to +0.13. The spectra were obtained at the Canada-France-Hawaii (CFH) 3.6 m telescope and have a measured resolution of 0.13 A and a median signal-to-noise ratio of approximately 50. For 18 of the 41 stars we have also made observations of the O I triplet at the Palomar 5 m telescope, the UH 2.2 m telescope, and the CFH telescope. Stellar parameters of Teff, log g, and (Fe/H) were carefully determined from several independent estimates. Abundances are determined for log N (Be/H) and (O/H) from measured equivalent widths, model parameters, and Kurucz (1991) model atmospheres with the RAI10 model atmosphere abundance program. The agreement with previously published Be detections is very good (a mean difference of 0.05 dex) for five of six determinations in four halo stars and in four of five disk stars. The agreement with very recently published O abundances is 0.0075 dex. It is plausible, but far from conclusive, that there is a plateau in the amount of Be present in the lowest metallicity stars: log N (Be/H) approximately -12.8 for (Fe/H) less than -2.2 As (Fe/H) increases from -2.2 to -1.0, log N (Be/H) increases and the slope is 1.2-1.3, indicating a faster increase in Be than in Fe. This is consistent with the production of Be by spallation reactions between cosmic rays and O atoms from massive stars and the production of Fe from intermediate mass stars. Evidence for stellar processing of Be exists in the disk stars and in at least two of the halo stars. A plot of Be abundance vs O abundances shows that Be increases as O1.12, indicating that Be is produced primarily is the vicinity of supernovae envelopes, but a small and interesting fraction is produced in

  1. American Muslim Undergraduates' Views on Evolution

    ERIC Educational Resources Information Center

    Fouad, Khadija Engelbrecht

    2016-01-01

    A qualitative investigation into American Muslim undergraduates' views on evolution revealed three main positions on evolution: theistic evolution, a belief in special creation of all species, and a belief in special creation of humans with evolution for all non-human species. One can conceive of the manner in which respondents chose their…

  2. Student Teachers' Approaches to Teaching Biological Evolution

    ERIC Educational Resources Information Center

    Borgerding, Lisa A.; Klein, Vanessa A.; Ghosh, Rajlakshmi; Eibel, Albert

    2015-01-01

    Evolution is fundamental to biology and scientific literacy, but teaching high school evolution is often difficult. Evolution teachers face several challenges including limited content knowledge, personal conflicts with evolution, expectations of resistance, concerns about students' conflicts with religion, and curricular constraints. Evolution…

  3. American Muslim Undergraduates' Views on Evolution

    ERIC Educational Resources Information Center

    Fouad, Khadija Engelbrecht

    2016-01-01

    A qualitative investigation into American Muslim undergraduates' views on evolution revealed three main positions on evolution: theistic evolution, a belief in special creation of all species, and a belief in special creation of humans with evolution for all non-human species. One can conceive of the manner in which respondents chose their…

  4. Student Teachers' Approaches to Teaching Biological Evolution

    ERIC Educational Resources Information Center

    Borgerding, Lisa A.; Klein, Vanessa A.; Ghosh, Rajlakshmi; Eibel, Albert

    2015-01-01

    Evolution is fundamental to biology and scientific literacy, but teaching high school evolution is often difficult. Evolution teachers face several challenges including limited content knowledge, personal conflicts with evolution, expectations of resistance, concerns about students' conflicts with religion, and curricular constraints. Evolution…

  5. Evolution, and the Conflict Between Conventional Wisdoms

    ERIC Educational Resources Information Center

    Lyman, R. A.

    1969-01-01

    Discusses the conflict between evolution and the "conventional wisdom of Christianity and the problems faced by the biology teacher in teaching evolution in certain communities. The practical consequences of both evolution and Christianity are compared and contrasted. Science teachers are urged to present the concepts of evolution honestly and…

  6. Galapagos III World Evolution Summit: why evolution matters.

    PubMed

    Paz-Y-Miño-C, Guillermo; Espinosa, Avelina

    There is no place on Earth like the Galapagos Islands and no better destination to discuss the reality of evolution. Under the theme 'Why Does Evolution Matter', the University San Francisco of Quito (USFQ), Ecuador, and its Galapagos Institute for the Arts and Sciences (GAIAS), organized the III World Evolution Summit in San Cristóbal Island. The 200-attendee meeting took place on 1 to 5 June 2013; it included 12 keynote speakers, 20 oral presentations by international scholars, and 31 posters by faculty, postdocs, and graduate and undergraduate students. The Summit encompassed five sessions: evolution and society, pre-cellular evolution and the RNA world, behavior and environment, genome, and microbes and diseases. USFQ and GAIAS launched officially the Lynn Margulis Center for Evolutionary Biology and showcased the Galapagos Science Center, in San Cristóbal, an impressive research facility conceptualized in partnership with the University of North Carolina at Chapel Hill, USA. USFQ and GAIAS excelled at managing the conference with exceptional vision and at highlighting the relevance of Galapagos in the history of modern evolutionary thinking; Charles Darwin's visit to this volcanic archipelago in 1835 unfolded unprecedented scientific interest in what today is a matchless World Heritage.

  7. Galapagos III World Evolution Summit: why evolution matters

    PubMed Central

    Paz-y-Miño-C, Guillermo; Espinosa, Avelina

    2016-01-01

    There is no place on Earth like the Galapagos Islands and no better destination to discuss the reality of evolution. Under the theme ‘Why Does Evolution Matter’, the University San Francisco of Quito (USFQ), Ecuador, and its Galapagos Institute for the Arts and Sciences (GAIAS), organized the III World Evolution Summit in San Cristóbal Island. The 200-attendee meeting took place on 1 to 5 June 2013; it included 12 keynote speakers, 20 oral presentations by international scholars, and 31 posters by faculty, postdocs, and graduate and undergraduate students. The Summit encompassed five sessions: evolution and society, pre-cellular evolution and the RNA world, behavior and environment, genome, and microbes and diseases. USFQ and GAIAS launched officially the Lynn Margulis Center for Evolutionary Biology and showcased the Galapagos Science Center, in San Cristóbal, an impressive research facility conceptualized in partnership with the University of North Carolina at Chapel Hill, USA. USFQ and GAIAS excelled at managing the conference with exceptional vision and at highlighting the relevance of Galapagos in the history of modern evolutionary thinking; Charles Darwin’s visit to this volcanic archipelago in 1835 unfolded unprecedented scientific interest in what today is a matchless World Heritage. PMID:26925190

  8. Cyanobacterial evolution during the Precambrian

    NASA Astrophysics Data System (ADS)

    Schirrmeister, Bettina E.; Sanchez-Baracaldo, Patricia; Wacey, David

    2016-07-01

    Life on Earth has existed for at least 3.5 billion years. Yet, relatively little is known of its evolution during the first two billion years, due to the scarceness and generally poor preservation of fossilized biological material. Cyanobacteria, formerly known as blue green algae were among the first crown Eubacteria to evolve and for more than 2.5 billion years they have strongly influenced Earth's biosphere. Being the only organism where oxygenic photosynthesis has originated, they have oxygenated Earth's atmosphere and hydrosphere, triggered the evolution of plants -being ancestral to chloroplasts- and enabled the evolution of complex life based on aerobic respiration. Having such a strong impact on early life, one might expect that the evolutionary success of this group may also have triggered further biosphere changes during early Earth history. However, very little is known about the early evolution of this phylum and ongoing debates about cyanobacterial fossils, biomarkers and molecular clock analyses highlight the difficulties in this field of research. Although phylogenomic analyses have provided promising glimpses into the early evolution of cyanobacteria, estimated divergence ages are often very uncertain, because of vague and insufficient tree-calibrations. Results of molecular clock analyses are intrinsically tied to these prior calibration points, hence improving calibrations will enable more precise divergence time estimations. Here we provide a review of previously described Precambrian microfossils, biomarkers and geochemical markers that inform upon the early evolution of cyanobacteria. Future research in micropalaeontology will require novel analyses and imaging techniques to improve taxonomic affiliation of many Precambrian microfossils. Consequently, a better understanding of early cyanobacterial evolution will not only allow for a more specific calibration of cyanobacterial and eubacterial phylogenies, but also provide new dates for the tree

  9. Musical emotions: Functions, origins, evolution

    NASA Astrophysics Data System (ADS)

    Perlovsky, Leonid

    2010-03-01

    Theories of music origins and the role of musical emotions in the mind are reviewed. Most existing theories contradict each other, and cannot explain mechanisms or roles of musical emotions in workings of the mind, nor evolutionary reasons for music origins. Music seems to be an enigma. Nevertheless, a synthesis of cognitive science and mathematical models of the mind has been proposed describing a fundamental role of music in the functioning and evolution of the mind, consciousness, and cultures. The review considers ancient theories of music as well as contemporary theories advanced by leading authors in this field. It addresses one hypothesis that promises to unify the field and proposes a theory of musical origin based on a fundamental role of music in cognition and evolution of consciousness and culture. We consider a split in the vocalizations of proto-humans into two types: one less emotional and more concretely-semantic, evolving into language, and the other preserving emotional connections along with semantic ambiguity, evolving into music. The proposed hypothesis departs from other theories in considering specific mechanisms of the mind-brain, which required the evolution of music parallel with the evolution of cultures and languages. Arguments are reviewed that the evolution of language toward becoming the semantically powerful tool of today required emancipation from emotional encumbrances. The opposite, no less powerful mechanisms required a compensatory evolution of music toward more differentiated and refined emotionality. The need for refined music in the process of cultural evolution is grounded in fundamental mechanisms of the mind. This is why today's human mind and cultures cannot exist without today's music. The reviewed hypothesis gives a basis for future analysis of why different evolutionary paths of languages were paralleled by different evolutionary paths of music. Approaches toward experimental verification of this hypothesis in

  10. Musical emotions: functions, origins, evolution.

    PubMed

    Perlovsky, Leonid

    2010-03-01

    Theories of music origins and the role of musical emotions in the mind are reviewed. Most existing theories contradict each other, and cannot explain mechanisms or roles of musical emotions in workings of the mind, nor evolutionary reasons for music origins. Music seems to be an enigma. Nevertheless, a synthesis of cognitive science and mathematical models of the mind has been proposed describing a fundamental role of music in the functioning and evolution of the mind, consciousness, and cultures. The review considers ancient theories of music as well as contemporary theories advanced by leading authors in this field. It addresses one hypothesis that promises to unify the field and proposes a theory of musical origin based on a fundamental role of music in cognition and evolution of consciousness and culture. We consider a split in the vocalizations of proto-humans into two types: one less emotional and more concretely-semantic, evolving into language, and the other preserving emotional connections along with semantic ambiguity, evolving into music. The proposed hypothesis departs from other theories in considering specific mechanisms of the mind-brain, which required the evolution of music parallel with the evolution of cultures and languages. Arguments are reviewed that the evolution of language toward becoming the semantically powerful tool of today required emancipation from emotional encumbrances. The opposite, no less powerful mechanisms required a compensatory evolution of music toward more differentiated and refined emotionality. The need for refined music in the process of cultural evolution is grounded in fundamental mechanisms of the mind. This is why today's human mind and cultures cannot exist without today's music. The reviewed hypothesis gives a basis for future analysis of why different evolutionary paths of languages were paralleled by different evolutionary paths of music. Approaches toward experimental verification of this hypothesis in

  11. JPSS CGS Evolution

    NASA Astrophysics Data System (ADS)

    Miller, S. W.; Grant, K. D.; Jamilkowski, M. L.

    2012-12-01

    Space Communications and Navigation (SCaN, which includes the Earth Observing System [EOS]), Metop for the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), Coriolis/WindSat for the DoD, as well as research activities of the National Science Foundation (NSF). The CGS architecture is evolving over the next few years for several key reasons: 1. "Operationalizing" Suomi NPP, which had originally been intended as a risk reduction mission 2. Leveraging lessons learned to date in multi-mission support 3. Taking advantage of newer, more reliable and efficient technologies 4. Satisfying new requirements and constraints due to the continually evolving budgetary environment Three key aspects of the CGS architecture are being prototyped as part of the path to improve operations in the 2015 timeframe. First, the front end architecture for mission data transport is being re-architected to improve reliability and address the incorporation of new ground stations. Second, the IDPS is undergoing a decoupling process to enhance its flexibility and modularity for supporting an array of potential new missions beyond those listed above. Finally, a solution for complete situational awareness across the CGS is being developed, to facilitate quicker and more efficient identification and resolution of system anomalies. This paper discusses the evolution of the CGS architecture to address these future mission needs.

  12. [Ribosomal RNA Evolution

    NASA Technical Reports Server (NTRS)

    1997-01-01

    It is generally believed that an RNA World existed at an early stage in the history of life. During this early period, RNA molecules are seen to be potentially involved in both catalysis and the storage of genetic information. Translation presents several interrelated themes of inquiry for exobiology. First, it is essential, for understanding the very origin of life, how peptides and eventually proteins might have come to be made on the early Earth in a template directed manner. Second, it is necessary to understand how a machinery of similar complexity to that found in the ribosomes of modern organisms came to exist by the time of the last common ancestor (as detected by 16S rRNA sequence studies). Third, the ribosomal RNAs themselves likely had a very early origin and studies of their history may be very informative about the nature of the RNA World. Moreover, studies of these RNAs will contribute to a better understanding of the potential roles of RNA in early evolution.During the past year we have ave conducted a comparative study of four completely sequenced bacterial genoames. We have focused initially on conservation of gene order. The second component of the project continues to build on the model system for studying the validity of variant 5S rRNA sequences in the vicinity of the modern Vibrio proteolyticus 5S rRNA that we established earlier. This system has made it possible to conduct a detailed and extensive analysis of a local portion of the sequence space. These core methods have been used to construct numerous mutants during the last several years. Although it has been a secondary focus, this work has continued over the last year such that we now have in excess of 125 V. proteolyticus derived constructs which have been made and characterized. We have also continued high resolution NMR work on RNA oligomers originally initiated by G. Kenneth Smith who was funded by a NASA Graduate Student Researcher's Fellowship Award until May of 1996. Mr. Smith

  13. Stellar Evolution and Social Evolution: A Study in Parallel Processes

    NASA Astrophysics Data System (ADS)

    Carneiro, Robert L.

    From the beginning of anthropology, social evolution has been one of its major interests. However, in recent years the study of this process has languished. Accordingly, those anthropologists who still consider social evolution to be of central importance to their discipline, and who continue to pursue it, find their endeavor bolstered when parallel instances of evolutionary reconstructions can be demonstrated in other fields. Stellar evolution has long been a prime interest to astronomers, and their progress in deciphering its course has been truly remarkable. In examining astronomers' reconstructions of stellar evolution, I have been struck by a number of similarities between ways stars and societies have evolved. The parallels actually begin with the method used by both disciplines, namely, the comparative method. In astronomy, the method involves plotting stars on a Hertzsprung-Russell Diagram, and interpreting, diachonically, the pattern made by essentially synchronic data used for plotting. The comparative method is particularly appropriate when one is studying a process that cannot be observed over its full range in the life of any single individual, be it a star or a society. Parallels also occur in that stars and societies have each followed distinctive stages in their evolution. These stages are, in both cases, sometimes unlinear and sometimes multilinear. Moreover, the distinction drawn by anthropologists between a pristine and a secondary state (which depends on whether state so represented is the first such occurrence in an area, or was a later development derivative from earlier states) finds its astronomical parallel in the relationship existing between Population II and Population I stars. These and other similarities between stellar and social evolution will be cited and discussed.

  14. Genetic Constraints on Protein Evolution

    PubMed Central

    Camps, Manel; Herman, Asael; Loh, Ern; Loeb, Lawrence A.

    2013-01-01

    Evolution requires the generation and optimization of new traits (“adaptation”) and involves the selection of mutations that improve cellular function. These mutations were assumed to arise by selection of neutral mutations present at all times in the population. Here we review recent evidence that indicates that deleterious mutations are more frequent in the population than previously recognized and these mutations play a significant role in protein evolution through continuous positive selection. Positively selected mutations include adaptive mutations, i.e. mutations that directly affect enzymatic function, and compensatory mutations, which suppress the pleiotropic effects of adaptive mutations. Compensatory mutations are by far the most frequent of the two and would allow potentially adaptive but deleterious mutations to persist long enough in the population to be positively selected during episodes of adaptation. Compensatory mutations are, by definition, context-dependent and thus constrain the paths available for evolution. This provides a mechanistic basis for the examples of highly constrained evolutionary landscapes and parallel evolution reported in natural and experimental populations. The present review article describes these recent advances in the field of protein evolution and discusses their implications for understanding the genetic basis of disease and for protein engineering in vitro. PMID:17917869

  15. Experimental evolution meets marine phytoplankton.

    PubMed

    Reusch, Thorsten B H; Boyd, Philip W

    2013-07-01

    Our perspective highlights potentially important links between disparate fields-biological oceanography, climate change research, and experimental evolutionary biology. We focus on one important functional group-photoautotrophic microbes (phytoplankton), which are responsible for ∼50% of global primary productivity. Global climate change currently results in the simultaneous change of several conditions such as warming, acidification, and nutrient supply. It thus has the potential to dramatically change phytoplankton physiology, community composition, and may result in adaptive evolution. Although their large population sizes, standing genetic variation, and rapid turnover time should promote swift evolutionary change, oceanographers have focussed on describing patterns of present day physiological differentiation rather than measure potential adaptation in evolution experiments, the only direct way to address whether and at which rate phytoplankton species will adapt to environmental change. Important open questions are (1) is adaptation limited by existing genetic variation or fundamental constraints? (2) Will complex ecological settings such as gradual versus abrupt environmental change influence adaptation processes? (3) How will increasing environmental variability affect the evolution of phenotypic plasticity patterns? Because marine phytoplankton species display rapid acclimation capacity (phenotypic buffering), a systematic study of reaction norms renders them particularly interesting to the evolutionary biology research community. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  16. Experimental evolution in biofilm populations

    PubMed Central

    Steenackers, Hans P.; Parijs, Ilse; Foster, Kevin R.; Vanderleyden, Jozef

    2016-01-01

    Biofilms are a major form of microbial life in which cells form dense surface associated communities that can persist for many generations. The long-life of biofilm communities means that they can be strongly shaped by evolutionary processes. Here, we review the experimental study of evolution in biofilm communities. We first provide an overview of the different experimental models used to study biofilm evolution and their associated advantages and disadvantages. We then illustrate the vast amount of diversification observed during biofilm evolution, and we discuss (i) potential ecological and evolutionary processes behind the observed diversification, (ii) recent insights into the genetics of adaptive diversification, (iii) the striking degree of parallelism between evolution experiments and real-life biofilms and (iv) potential consequences of diversification. In the second part, we discuss the insights provided by evolution experiments in how biofilm growth and structure can promote cooperative phenotypes. Overall, our analysis points to an important role of biofilm diversification and cooperation in bacterial survival and productivity. Deeper understanding of both processes is of key importance to design improved antimicrobial strategies and diagnostic techniques. PMID:26895713

  17. Genetic constraints on protein evolution.

    PubMed

    Camps, Manel; Herman, Asael; Loh, Ern; Loeb, Lawrence A

    2007-01-01

    Evolution requires the generation and optimization of new traits ("adaptation") and involves the selection of mutations that improve cellular function. These mutations were assumed to arise by selection of neutral mutations present at all times in the population. Here we review recent evidence that indicates that deleterious mutations are more frequent in the population than previously recognized and that these mutations play a significant role in protein evolution through continuous positive selection. Positively selected mutations include adaptive mutations, i.e. mutations that directly affect enzymatic function, and compensatory mutations, which suppress the pleiotropic effects of adaptive mutations. Compensatory mutations are by far the most frequent of the two and would allow potentially adaptive but deleterious mutations to persist long enough in the population to be positively selected during episodes of adaptation. Compensatory mutations are, by definition, context-dependent and thus constrain the paths available for evolution. This provides a mechanistic basis for the examples of highly constrained evolutionary landscapes and parallel evolution reported in natural and experimental populations. The present review article describes these recent advances in the field of protein evolution and discusses their implications for understanding the genetic basis of disease and for protein engineering in vitro.

  18. Oxygen and Early Animal Evolution

    NASA Astrophysics Data System (ADS)

    Xiao, S.

    2012-12-01

    It is often hypothesized that the rise of animals was triggered by an increase in O2 levels in the atmosphere and oceans. However, this hypothesis is remarkably difficult to test, because the timing of animal divergences is poorly resolved, the physiology of early animals is often unknown, estimates of past pO2 levels come with large error bars, and causal relationships between oxygenation and animal evolution are difficult to establish. Nonetheless, existing phylogenetic, paleontological, and geochemical data indicate that the evolution of macroscopic animals and motile macrometazoans with energetically expensive lifestyles may be temporally coupled with ocean oxygenation events in the Ediacaran Period. Thus, it is plausible that ocean oxygenation may have been a limiting factor in the early evolution of macroscopic, complex, and metabolically aggressive animals (particularly bilaterian animals). However, ocean oxygenation and animal evolution were likely engaged in two-way interactions: Ediacaran oxygenation may have initially lifted a physiological barrier for the evolution of animal size, motility, and active lifestyles, but subsequent animal diversification in the Paleozoic may have also changed oceanic redox structures. Viewed in a broader context, the early evolutionary history of animals was contingent upon a series of events, including genetic preparation (developmental genetics), environmental facilitation (oceanic oxygenation), and ecological escalation (Cambrian explosion), but the rise of animals to ecological importance also had important geobiological impacts on oceanic redox structures, sedimentary fabrics, and global geochemical cycles.

  19. Teaching evolution: challenging religious preconceptions.

    PubMed

    Lovely, Eric C; Kondrick, Linda C

    2008-08-01

    Teaching college students about the nature of science should not be a controversial exercise. College students are expected to distinguish between astronomy and astrology, chemistry and alchemy, evolution and creationism. In practice, however, the conflict between creationism and the nature of science may create controversy in the classroom, even walkouts, when the subject of evolution is raised. The authors have grappled with the meaning of such behaviors. They surveyed 538 students in a public, liberal arts college. Pre/post course surveys were analyzed to track changes in student responses to questions that were either consistent or inconsistent with the Theory of Evolution after a semester of instruction in a college biology or zoology course in which evolution was taught. Many students who were initially undecided about issues regarding evolution had shifted in their viewpoints by the end of the course. It was found that more education about the evidence for and the mechanics of evolutionary processes did not necessarily move students toward a scientific viewpoint. The authors also discovered a "wedge" effect among students who were undecided about questions pertaining to human ancestry at the beginning of the course. About half of these students shifted to a scientific viewpoint at the end of the course; the other half shifted toward agreement with statements consistent with creationism.

  20. Evolution in Littorina: ecology matters

    NASA Astrophysics Data System (ADS)

    Johannesson, Kerstin

    2003-03-01

    Organisms of marine rocky shores are exposed to physical stress from abiotic factors, such as temperature, salinity and wave action. These factors vary over compressed temporal and spatial scales, producing an exceedingly heterogeneous habitat with steep gradients of selection, and it seems likely that this has a strong influence on the evolution of populations of rocky shore organisms. With the periwinkles (genus Littorina) as a model group, I review strategies for coping with small-scale heterogeneous environments and what implications these strategies have on the evolution of these species. Some species of Littorina have long-lived pelagic larvae and sites of various habitats are thus recruited from a common gene pool. This largely prevents local adaptation but minor adjustments are possible through a plastic phenotype. Other species of the genus are directly developing with no larval dispersal and among these there is evidence of strong local adaptation forming distinct ecotypes in contrasting habitats by parallel evolution. In at least one of the directly developing species ( L. saxatilis) divergent selection among ecotypes has resulted in partial reproductive barriers that further impede gene flow among ecotypes. Furthermore, convergent evolution among species has produced superficially similar morphs in different habitats. Ecotype formation, ecological reproductive barriers and convergence among species all indicate that ecological processes are critical for evolution of Littorina species.

  1. Evolution of rapid nerve conduction.

    PubMed

    Castelfranco, Ann M; Hartline, Daniel K

    2016-06-15

    Rapid conduction of nerve impulses is a priority for organisms needing to react quickly to events in their environment. While myelin may be viewed as the crowning innovation bringing about rapid conduction, the evolution of rapid communication mechanisms, including those refined and enhanced in the evolution of myelin, has much deeper roots. In this review, a sequence is traced starting with diffusional communication, followed by transport-facilitated communication, the rise of electrical signaling modalities, the invention of voltage-gated channels and "all-or-none" impulses, the emergence of elongate nerve axons specialized for communication and their fine-tuning to enhance impulse conduction speeds. Finally within the evolution of myelin itself, several innovations have arisen and have been interactively refined for speed enhancement, including the addition and sealing of layers, their limitation by space availability, and the optimization of key parameters: channel density, lengths of exposed nodes and lengths of internodes. We finish by suggesting several design principles that appear to govern the evolution of rapid conduction. This article is part of a Special Issue entitled SI: Myelin Evolution. Copyright © 2016. Published by Elsevier B.V.

  2. A new paradigma on the plant evolution: from a natural evolution to an artificial evolution?

    PubMed

    Bennici, Andrea

    2005-01-01

    After evidencing the great importance of plants for animals and humans in consequence of the photosynthesis, several considerations on plant evolution are made. One of the peculiar characteristics of the plant is the sessile property, due especially to the cell wall. This factor, principally, strengthened by the photosynthetic process, determined the particular developmental pattern of the plant, which is characterized by the continuous formation of new organs. The plant immobility, although negative for its survival, has been, in great part, overcome by the acquisition of the capacity of adaptation (plasticity) to the environmental stresses and changes, and the establishment of more adapted genotypes. This capacity to react to the external signals induced Trewavas to speak of "plant intelligence". The plant movement incapacity and the evolution of the sexual reproduction system were strongly correlated. In this context, the evolution of the flower in the Angiosperms has been particularly important to allow the male gamete to fertilize the immobile female gamete. Moreover, the formation of fruit and seed greatly improved the dispersal and conservation of the progeny in the environment. With the flower, mechanisms to favour the outcrossing among different individuals appeared, which are essential to increase the genetic variability and, then, the plant evolution itself. Although the Angiosperms seem highly evolved, the plant evolution is not surely finished, because many reported morpho-physiological processes may be still considered susceptible of further improvement. In the last years the relationships among humans, plants and environment are becoming closer and closer. This is due to the use of the DNA recombinant techniques with the aim to modify artificially plant characters. Therefore, the risk of a plant evolution strongly directed towards practical or commercial objectives, or "an artificial evolution", may be hypothesized.

  3. The evolution of tuberculosis virulence.

    PubMed

    Basu, Sanjay; Galvani, Alison P

    2009-07-01

    The evolution of Mycobacterium tuberculosis presents several challenges for public health. HIV and resistance to antimycobacterial medications have evolutionary implications for how Mycobacterium tuberculosis will evolve, as these factors influence the host environment and transmission dynamics of tuberculosis strains. We present an evolutionary invasion analysis of tuberculosis that characterizes the direction of tuberculosis evolution in the context of different natural and human-driven selective pressures, including changes in tuberculosis treatment and HIV prevalence. We find that the evolution of tuberculosis virulence can be affected by treatment success rates, the relative transmissibility of emerging strains, the rate of reactivation from latency among hosts, and the life expectancy of hosts. We find that the virulence of tuberculosis strains may also increase as a consequence of rising HIV prevalence, requiring faster case detection strategies in areas where the epidemics of HIV and tuberculosis collide.

  4. Evolution of the Space Shuttle

    NASA Astrophysics Data System (ADS)

    Nease, Ardell

    1993-02-01

    This paper initially examines the Space Shuttle's past and future role in the exploration and exploitation of space and then discusses the evolution of the Space Shuttle as a cost effective design solution to the nation's and the world's space requirements. The argument for Shuttle evolution is presented and a cost effective approach to evolving the Space Shuttle into tomorrow's Space Transportation System is described. Near term upgrades can increase safety and reliability, avoid obsolescence, reduce operations costs, and increase performance; they can be followed by the long term block changes that incorporate new technologies and make the Space Shuttle dramatically more useful and cost effective to operate. The balance between continued Shuttle System life vs replacement system development and production is placed in the perspective of mission needs, technological leverage, and fiscal reality. The paper concludes that the evolution of the Space Shuttle is the most cost effective solution to the nation's space transportation needs for more than thirty years.

  5. Biological evolution and statistical physics

    NASA Astrophysics Data System (ADS)

    Drossel, Barbara

    2001-03-01

    This review is an introduction to theoretical models and mathematical calculations for biological evolution, aimed at physicists. The methods in the field are naturally very similar to those used in statistical physics, although the majority of publications have appeared in biology journals. The review has three parts, which can be read independently. The first part deals with evolution in fitness landscapes and includes Fisher's theorem, adaptive walks, quasispecies models, effects of finite population sizes, and neutral evolution. The second part studies models of coevolution, including evolutionary game theory, kin selection, group selection, sexual selection, speciation, and coevolution of hosts and parasites. The third part discusses models for networks of interacting species and their extinction avalanches. Throughout the review, attention is paid to giving the necessary biological information, and to pointing out the assumptions underlying the models, and their limits of validity.

  6. Evolution of the Cosmic Web

    NASA Astrophysics Data System (ADS)

    Einasto, J.

    2017-07-01

    In the evolution of the cosmic web dark energy plays an important role. To understand the role of dark energy we investigate the evolution of superclusters in four cosmological models: standard model SCDM, conventional model LCDM, open model OCDM, and a hyper-dark-energy model HCDM. Numerical simulations of the evolution are performed in a box of size 1024 Mpc/h. Model superclusters are compared with superclusters found for Sloan Digital Sky Survey (SDSS). Superclusters are searched using density fields. LCDM superclusters have properties, very close to properties of observed SDSS superclusters. Standard model SCDM has about 2 times more superclusters than other models, but SCDM superclusters are smaller and have lower luminosities. Superclusters as principal structural elements of the cosmic web are present at all cosmological epochs.

  7. Functional evolution of nuclear structure

    PubMed Central

    Dawson, Scott C.

    2011-01-01

    The evolution of the nucleus, the defining feature of eukaryotic cells, was long shrouded in speculation and mystery. There is now strong evidence that nuclear pore complexes (NPCs) and nuclear membranes coevolved with the endomembrane system, and that the last eukaryotic common ancestor (LECA) had fully functional NPCs. Recent studies have identified many components of the nuclear envelope in living Opisthokonts, the eukaryotic supergroup that includes fungi and metazoan animals. These components include diverse chromatin-binding membrane proteins, and membrane proteins with adhesive lumenal domains that may have contributed to the evolution of nuclear membrane architecture. Further discoveries about the nucleoskeleton suggest that the evolution of nuclear structure was tightly coupled to genome partitioning during mitosis. PMID:22006947

  8. Extinction events can accelerate evolution.

    PubMed

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific in the long term.

  9. Cryogenian evolution of stigmasteroid biosynthesis

    PubMed Central

    Hoshino, Yosuke; Poshibaeva, Aleksandra; Meredith, William; Snape, Colin; Poshibaev, Vladimir; Versteegh, Gerard J. M.; Kuznetsov, Nikolay; Leider, Arne; van Maldegem, Lennart; Neumann, Mareike; Naeher, Sebastian; Moczydłowska, Małgorzata; Brocks, Jochen J.; Jarrett, Amber J. M.; Tang, Qing; Xiao, Shuhai; McKirdy, David; Das, Supriyo Kumar; Alvaro, José Javier; Sansjofre, Pierre; Hallmann, Christian

    2017-01-01

    Sedimentary hydrocarbon remnants of eukaryotic C26–C30 sterols can be used to reconstruct early algal evolution. Enhanced C29 sterol abundances provide algal cell membranes a density advantage in large temperature fluctuations. Here, we combined a literature review with new analyses to generate a comprehensive inventory of unambiguously syngenetic steranes in Neoproterozoic rocks. Our results show that the capacity for C29 24-ethyl-sterol biosynthesis emerged in the Cryogenian, that is, between 720 and 635 million years ago during the Neoproterozoic Snowball Earth glaciations, which were an evolutionary stimulant, not a bottleneck. This biochemical innovation heralded the rise of green algae to global dominance of marine ecosystems and highlights the environmental drivers for the evolution of sterol biosynthesis. The Cryogenian emergence of C29 sterol biosynthesis places a benchmark for verifying older sterane signatures and sets a new framework for our understanding of early algal evolution. PMID:28948220

  10. Reconstructing the evolution of mind.

    PubMed

    Povinelli, D J

    1993-05-01

    Since Darwin, the idea of intellectual continuity has gripped comparative psychology. Psychological evolution has been viewed as the accumulation of gradual changes over time, resulting in an unbroken chain of mental capacities throughout the diversity of life. Some researchers have even maintained that no fundamental psychological differences exist among species. An alternative model argues that a rather profound new psychology related to mental state attribution may have evolved recently in the primate order. The author explores recent experimental research from chimpanzees, rhesus monkeys, and children that is consistent with this second model of psychological evolution. Drawing on the fields of developmental, comparative, and social psychology, as well as evolutionary and developmental biology, the author outlines a research agenda aimed at reconstructing the evolution of metacognition.

  11. Extinction Events Can Accelerate Evolution

    PubMed Central

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific in the long term. PMID:26266804

  12. Experimental evolution of Bacillus subtilis.

    PubMed

    Zeigler, Daniel R; Nicholson, Wayne L

    2017-09-01

    The endospore-forming bacteria have persisted on earth perhaps 3Ga, leveraging the flexibility of their distinctive lifestyle to adapt to a remarkably wide range of environments. This process of adaptation can be investigated through the simple but powerful technique of laboratory evolution. Evolved strains can be analyzed by whole genome sequencing and an array of omics technologies. The intensively studied, genetically tractable endospore-former, Bacillus subtilis, is an ideal subject for laboratory evolution experiments. Here, we describe the use of the B. subtilis model system to study the adaptation of these bacteria to reduced and stringent selection for endospore formation, as well as to novel environmental challenges of low atmospheric pressure, high ultraviolet radiation, and unfavourable growth temperatures. In combination with other approaches, including comparative genomics and environmental field work, laboratory evolution may help elucidate how these bacteria have so successfully adapted to life on earth, and perhaps beyond. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  13. Complexity of ruminant masticatory evolution.

    PubMed

    Fraser, Danielle; Rybczynski, Natalia

    2014-10-01

    The evolution of robust jaws, hypsodont teeth, and large chewing muscles among grazing ruminants is a quintessential example of putative morphological adaptation. However, the degree of correlated evolution (i.e., to what extent the grazer feeding apparatus represents an evolutionary module), especially of soft and hard tissues, remains poorly understood. Recent generation of large datasets and phylogenetic information has made testing hypotheses of correlated evolution possible. We, therefore, test for correlated evolution among various traits of the ruminant masticatory apparatus including tooth crown height, jaw robustness, chewing muscle size, and characters of the molar occlusal surfaces, using phylogenetic and nonphylogenetic comparative methods as well as phylogenetic evolutionary model selection. We find that the large masseter muscles of grazing ruminants evolved with the inclusion of grass in the diet, an increase in the proportion of occlusal enamel bands oriented parallel to the chewing stroke, and possibly hypsodonty. We suggest that the masseter evolved under two evolutionary regimes: i) selection for higher masticatory forces during chewing and ii) flattening of the tooth profile, which resulted in reduced tooth guidance and, thus, a requirement for more chewing muscle activity during each chewing stroke, in agreement with previous research. The linear jaw metrics (depth of the mandibular angle, mandibular angle width, and length of the superficial masseteric scar) all show correlated evolution with hypsodonty and the proportion of enamel bands oriented parallel to the chewing stroke. We suggest that changes in the shape of the mandible represent the combined effects of selection for a reorientation of the chewing stroke, so as to emphasize horizontal translation of the teeth, and accommodation of high-crowned teeth. Our analyses show that the ruminant feeding apparatus is an evolutionary mosaic with its various components showing both correlated and

  14. Language Evolution: A Changing Perspective.

    PubMed

    Corballis, Michael C

    2017-04-01

    From ancient times, religion and philosophy have regarded language as a faculty bestowed uniquely and suddenly on our own species, primarily as a mode of thought with communication as a byproduct. This view persists among some scientists and linguists and is counter to the theory of evolution, which implies that the evolution of complex structures is incremental. I argue here that language derives from mental processes with gradual evolutionary trajectories, including the generative capacities to travel mentally in time and space and into the minds of others. What may be distinctive in humans is the means to communicate these mental experiences along with knowledge gained from them.

  15. Origins and Evolution of Life

    NASA Astrophysics Data System (ADS)

    Gargaud, Muriel; López-García, Purificación; Martin, Hervé

    2011-01-01

    Part I. What Is Life?: 1. Problems raised by a definition of life M. Morange; 2. Some remarks about uses of cosmological anthropic 'principles' D. Lambert; 3. Minimal cell: the biologist point of view C. Brochier-Armanet; 4. Minimal cell: the computer scientist point of view H. Bersini; 5. Origins of life: computing and simulation approaches B. Billoud; Part II. Astronomical and Geophysical Context of the Emergence of Life: 6. Organic molecules in interstellar medium C. Ceccarelli and C. Cernicharo; 7. Cosmochemical evolution and the origin of life: insights from meteorites S. Pizzarello; 8. Astronomical constraints on the emergence of life M. Gounelle and T. Montmerle; 9. Formation of habitable planets J. Chambers; 10. The concept of galactic habitable zone N. Prantzos; 11. The young Sun and its influence on planetary atmospheres M. Güdel and J. Kasting; 12. Climates of the Earth G. Ramstein; Part III. Role of Water in the Emergence of Life: 13. Liquid water: a necessary condition to all forms of life K. Bartik, G. Bruylants, E. Locci and J. Reisse; 14. The role of water in the formation and evolution of planets T. Encrenaz; 15. Water on Mars J. P. Bibring; Part IV. From Non-Living Systems to Life: 16. Energetic constraints on prebiotic pathways: application to the emergence of translation R. Pascal and L. Boiteau; 17. Comparative genomics and early cell evolution A. Lazcano; 18. Origin and evolution of metabolisms J. Peretó; Part V. Mechanisms for Life Evolution: 19. Molecular phylogeny: inferring the patterns of evolution E. Douzery; 20. Horizontal gene transfer: mechanisms and evolutionary consequences D. Moreira; 21. The role of symbiosis in eukaryotic evolution A. Latorre, A. Durbán, A. Moya and J. Peretó; Part VI. Life in Extreme Conditions: 22. Life in extreme conditions: Deinococcus radiodurans, an organism able to survive prolonged desiccation and high doses of ionising radiation S. Sommer and M. Toueille; 23. Molecular effects of UV and ionizing

  16. Computational optimization and biological evolution.

    PubMed

    Goryanin, Igor

    2010-10-01

    Modelling and optimization principles become a key concept in many biological areas, especially in biochemistry. Definitions of objective function, fitness and co-evolution, although they differ between biology and mathematics, are similar in a general sense. Although successful in fitting models to experimental data, and some biochemical predictions, optimization and evolutionary computations should be developed further to make more accurate real-life predictions, and deal not only with one organism in isolation, but also with communities of symbiotic and competing organisms. One of the future goals will be to explain and predict evolution not only for organisms in shake flasks or fermenters, but for real competitive multispecies environments.

  17. Phenomenological implementations of TMD evolution

    SciTech Connect

    Boglione, Mariaelena; Gonzalez Hernandez, Jose Osvaldo; Melis, Stefano; Prokudin, Alexey

    2015-03-01

    Although the theoretical set-up of TMD evolution appears to be well established, its phenomenological implementations still require special attention, particularly as far as the interplay between perturbative and non-perturbative contributions is concerned. These issues have been extensively studied in Drell-Yan processes, where they seem to be reasonably under control. Instead, applying the same prescriptions and methodologies to Semi-Inclusive Deep Inelastic (SIDIS) processes is, at present, far from obvious. Some of the controversies related to the applications of TMD Evolution to SIDIS processes will be discussed with practical examples, exploring different kinematical configurations of SIDIS experiments.

  18. Evolution in an acidifying ocean.

    PubMed

    Sunday, Jennifer M; Calosi, Piero; Dupont, Sam; Munday, Philip L; Stillman, Jonathon H; Reusch, Thorsten B H

    2014-02-01

    Ocean acidification poses a global threat to biodiversity, yet species might have the capacity to adapt through evolutionary change. Here we summarize tools available to determine species' capacity for evolutionary adaptation to future ocean change and review the progress made to date with respect to ocean acidification. We focus on two key approaches: measuring standing genetic variation within populations and experimental evolution. We highlight benefits and challenges of each approach and recommend future research directions for understanding the modulating role of evolution in a changing ocean.

  19. Dynamical Evolution of Stellar Systems

    NASA Astrophysics Data System (ADS)

    Baumgardt, H.

    2016-11-01

    Dynamical simulations have become a powerful tool to study the evolution of star clusters due to hardware and software progresses in recent years. Here, I review the state of the art of N-body and other simulation techniques and show what we have learned from these simulations about the dynamical evolution of star clusters. Special attention is given to the results on the lifetimes of star clusters as a function of their environment, the internal changes of the mass functions, the influence of primordial gas expulsion on the ratio of first to second generation stars in globular clusters, and the possible presence of intermediate-mass black holes in star clusters.

  20. Evolution of vertebrate colour vision.

    PubMed

    Jacobs, Gerald H; Rowe, Mickey P

    2004-07-01

    Recent years have witnessed a growing interest in learning how colour vision has evolved. This trend has been fuelled by an enhanced understanding of the nature and extent of colour vision among contemporary species, by a deeper understanding of the paleontological record and by the application of new tools from molecular biology. This review provides an assessment of the progress in understanding the evolution of vertebrate colour vision. In so doing, we offer accounts of the evolution of three classes of mechanism important for colour vision--photopigment opsins, oil droplets and retinal organisation--and then examine details of how colour vision has evolved among mammals and, more specifically, among primates.