Science.gov

Sample records for 50-year time period

  1. Influence of climatic conditions on production of Stipa-Bouteloua prairie over a 50-year period

    SciTech Connect

    Smoliak, S.

    1986-03-01

    Range forage yields obtained over a 50-year period at the Research Substation near Manyberries in southeastern Alberta were analyzed in relation to several climatic factors. The basic variables were precipitation, pan evaporation, temperature, hours of sunlight, and wind velocity. The precipitation from April through July was highly correlated with range forage production and this relationship could be utilized to predict the annual forage production by 1 August each year. A slightly better correlation was obtained when range forage production was related to the total of the previous September plus the current April through July precipitation. Pan evaporation totals, mean temperature, and hours of sunlight were negatively correlated with forage production, while wind velocity during the growing season showed a low relationship to forage production. Stepwise regression analysis showed that the inclusion of May and June mean temperatures with June and July precipitation accounted for 63% of the variation in range forage production. The predicted forage yield would be useful in making management decisions or adjustments, especially during drought periods, while the long-term forage yield data can be utilized in range forage models or in validating their effectiveness.

  2. Long-term variation analysis of a tropical river's annual streamflow regime over a 50-year period

    NASA Astrophysics Data System (ADS)

    Seyam, Mohammed; Othman, Faridah

    2015-07-01

    Studying the long-term changes of streamflow is an important tool for enhancing water resource and river system planning, design, and management. The aim of this work is to identify the long-term variations in annual streamflow regime over a 50-year period from 1961 to 2010 in the Selangor River, which is one of the main tropical rivers in Malaysia. Initially, the data underwent preliminary independence, normality, and homogeneity testing using the Pearson correlation coefficient and Shapiro-Wilk and Pettitt's tests, respectively. The work includes a study and analysis of the changes through nine variables describing the annual streamflow and variations in the yearly duration of high and low streamflows. The analyses were conducted via two time scales: yearly and sub-periodic. The sub-periods were obtained by segmenting the 50 years into seven sub-periods by two techniques, namely the change-point test and direct method. Even though analysis revealed nearly negligible changes in mean annual flow over the study period, the maximum annual flow generally increased while the minimum annual flow significantly decreased with respect to time. It was also observed that the variables describing the dispersion in streamflow continually increased with respect to time. An obvious increase was detected in the yearly duration of danger level of streamflow, a slight increase was noted in the yearly duration of warning and alert levels, and a slight decrease in the yearly duration of low streamflow was found. The perceived changes validate the existence of long-term changes in annual streamflow regime, which increase the probability of floods and droughts occurring in future. In light of the results, attention should be drawn to developing water resource management and flood protection plans in order to avert the harmful effects potentially resulting from the expected changes in annual streamflow regime.

  3. An analysis of the sequence variability of meningococcal fHbp, NadA and NHBA over a 50-year period in the Netherlands.

    PubMed

    Bambini, Stefania; Piet, Jurgen; Muzzi, Alessandro; Keijzers, Wendy; Comandi, Sara; De Tora, Lisa; Pizza, Mariagrazia; Rappuoli, Rino; van de Beek, Diederik; van der Ende, Arie; Comanducci, Maurizio

    2013-01-01

    Studies of meningococcal evolution and genetic population structure, including the long-term stability of non-random associations between variants of surface proteins, are essential for vaccine development. We analyzed the sequence variability of factor H-binding protein (fHbp), Neisserial Heparin-Binding Antigen (NHBA) and Neisseria adhesin A (NadA), three major antigens in the multicomponent meningococcal serogroup B vaccine 4CMenB. A panel of invasive isolates collected in the Netherlands over a period of 50 years was used. To our knowledge, this strain collection covers the longest time period of any collection available worldwide. Long-term persistence of several antigen sub/variants and of non-overlapping antigen sub/variant combinations was observed. Our data suggest that certain antigen sub/variants including those used in 4CMenB are conserved over time and promoted by selection. PMID:23717687

  4. A Perspective on the Intended Science Curriculum in Iceland and its `Transformation' over a Period of 50 Years

    NASA Astrophysics Data System (ADS)

    Thorolfsson, Meyvant; Finnbogason, Gunnar E.; Macdonald, Allyson

    2012-11-01

    In recent decades, a consensus has emerged among educators and scientists that all compulsory school students need good science education. The debate about its purpose and nature as a school subject in an emerging information society has not been as conclusive. To further understand this, it helps to examine how the science curriculum has transformed and what forces have shaped it as a core curricular area over time. This article sheds light on the transformation of the science curriculum for compulsory schools in Iceland in force from 1960 to 2010. Using criteria based on curriculum ideologies regarding the function of learners, instructors and subject matter in the learning process and the orientation of content and product versus process and development, it offers findings from content analysis of the intended science curriculum. The official curriculum was studied and conceptualised as it has evolved over time. The curriculum developers appear to have been striving for a compromise between conflicting views, resulting in what the authors of this article conceive as a 'kaleidoscopic quilt' of ideas over the period studied.

  5. 50 years of JETP Letters

    NASA Astrophysics Data System (ADS)

    Pastukhov, V. P.

    2015-04-01

    This paper briefly traces the 50-year history of the journal Pis'ma v Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki (JETP Letters), whose first issue was published on 1 April 1965. The journal is intended for a wide circle of physicists-readers as a fast publication channel for short communications on new results from research of the highest significance and highest priority in all areas of experimental and theoretical physics. Today, the journal celebrates numerous important contributions to the development of physics both in Russia and worldwide. Over a historically short period, JETP Letters developed into a highly authoritative and influential source for physicists engaged in a wide range of fields. Due to the wise and well-timed editorial policy, the journal continues to retain its leadership position, despite the difficulties the entire science periodical literature - and indeed the whole of science - is currently experiencing in Russia.

  6. ISME Celebrates 50 Years

    ERIC Educational Resources Information Center

    Teaching Music, 2004

    2004-01-01

    When members of the International Society for Music Education (ISME) met in Tenerife, Canary Islands, Spain in July for the 26th ISME World Conference, the gathering was an opportunity to share music from around the world, and to attend music education workshops. It was also an opportunity for its members to look back on the rich 50-year history…

  7. Glacier Shrinkage In The East Pamir Plateau In China During The Last 50 Years As Revealed By Two Times' Inventories

    NASA Astrophysics Data System (ADS)

    Wang, N.; Liu, S.; Xu, J.; Guo, W.

    2013-05-01

    The east Pamir Plateau located in China is the source area of the Kaxigar River, one of the tributary of the Tarim River in southern Xinjiang and a vital river to the social and economic development of Kaxigar City. Glaciers in the region play an important role as for the melting water nourishment and seasonal and decadal regulation to the runoff of the Kaxigar River. Early results indicate that glaciers in the region were in a slight retreat during the early 1960s and 2001 with area reduction by 6.2%. To understand their most recent dynamics of glaciers in the region, we have compiled a new inventory of these glaciers based on Landsat TM/ETM+ images acquired in 2009 without clouds and snow cover in the glacierized mountains. At the same time, we have updated the first glacier inventory by digitizing glacier outlines from topographical maps with modification and verification mostly based on aerial photographs. Our results indicate the total glacier area of 2564km2 in 1962 has become decreased to 2038km2 in 2009, 20.5% smaller than their original total. Small glaciers have experienced higher area reduction rate than that of large glaciers, the 11188 glaciers smaller than 10km2 have lost 27.8% of the total area while those 48 glaciers larger than 10km2 have decreased by 11.3% in area. However, there are 7 glaciers of which 6 glaciers with debris cover showing an advancing trend during the same period with average advance by 470m during 1963 and 2009. Compared with early observation, glacier retreat in the region seems accelerated which may be attributed to regional climate warming.

  8. 50-year return-period wet-snow load estimation based on weather station data for overhead line design in France

    NASA Astrophysics Data System (ADS)

    Ducloux, H.; Nygaard, B. E.

    2014-11-01

    Historically, as far as wet-snow loads were concerned, overhead line design was often based on experience or long-term applications with positive results. New standard like CENELEC EN 580341-1 (2012) take into account characteristic loads, i.e. 50-year return-period loads, for the overhead line design. This article proposes a method to estimate characteristic wet-snow loads based on meteorological data recorded at weather stations. The model used to calculate those loads is mainly inspired by a recent article written by Nygaard et al. (2013a) in which a new parameterization is proposed for the classical cylindrical wet-snow accretion model, as described in ISO 12494 standard (2001), annex C. After a complete description of the model and its parameterization adapted to French wet-snow events, the statistical issues are examined. Then, the model is used with the meteorological data of 87 weather stations in order to calculate wet-snow loads whose relevance has been positively tested according to real damages recorded in a complete wet-snow event database. At last, the characteristic loads of those 87 stations have been determined according to all the loads generated by the model and processed by a peak-over-threshold (POT) method. A practical method to determine the 90% confidence intervals of those characteristic values is given. As it is demonstrated that there is only one value of the ice class (IC) masses proposed by ISO 12494 in each confidence interval, characteristic loads can be easily expressed in terms of ICs. That method shows that ICs ranging from R1 (0.5 kg m-1) to R5 (5 kg m-1) could be used for overhead line design in France.

  9. Discovering Astronomy 50 Years Ago

    NASA Astrophysics Data System (ADS)

    Mouradian, Z.

    2008-09-01

    Three years after graduating in astronomy from Bucharest University, I was finally recruited by the Bucharest Observatory to participate in the International Geophysical Year. I joined the Observatory as the third fellow of the Solar Department. There, I became an expert in satellite affairs thanks to a TV broadcast shot. I was in charge of adjusting the newly received solar instruments and contributed to the international campaign, including the solar patrol. Since it was absolutely impossible for me to start a thesis at that time, I moved to France and started a new career in the Solar Department of Paris-Meudon Observatory. My experience at the Bucharest Observatory was fundamental to the rest of my work over the following 50 years. My cooperation with the Bucharest Observatory increased after 1992 and still continues today.

  10. Effect of arm position and foot placement on the five times sit-to-stand test completion times of female adults older than 50 years of age

    PubMed Central

    Ng, Shamay S.M.; Kwong, Patrick W.H.; Chau, Michael S.P.; Luk, Isaac C.Y.; Wan, Sam S.; Fong, Shirley S.M.

    2015-01-01

    The five times-sit-to stand test (FTSTS) is a clinical test which is commonly used to assessed the functional muscle strength of the lower limbs of older adults. The aim of this study was to examine the effect of different arm positions and foot placements on the FTSTS completion times of older female adults. [Subjects and Methods] Twenty-nine healthy female subjects, aged 63.1±5.3 years participated in this cross-sectional study. The times required to complete the FTSTS with 3 different arm positions (hands on thighs, arms crossed over chest, and an augmented arm position with the arms extended forward) and 2 foot placements (neutral and posterior) were recorded. The interaction effect and main effect of arm positions and foot placements were examined using a 3 (arm position) × 2 (foot placement) two-way repeated measures analysis of variance (ANOVA). [Results] There was no interaction effect among the 3 arm positions in the 2 foot placements. A significant main effect was identified for foot placement, but not arm position. Posterior foot placement led to a shorter FTSTS time compared to that of normal foot placement. [Conclusion] With the same arm position, FTSTS completion times with posterior foot placement tended to be shorter. Therefore, the standard foot placement should be used for FTSTS administration. PMID:26180314

  11. 50 years of snow stratigraphy observations

    NASA Astrophysics Data System (ADS)

    Johansson, C.; Pohjola, V.; Jonasson, C.; Challagan, T. V.

    2012-04-01

    With start in autumn 1961 the Abisko Scientific Research Station (ASRS) located in the Swedish sub Arctic has performed snow stratigraphy observations, resulting in a unique 50 year long time series of data. The data set contains grain size, snow layer hardness, grain compactness and snow layer dryness, observed every second week during the winter season. In general snow and snow cover are important factors for the global radiation budget, and the earth's climate. On a more local scale the layered snowpack creates a relatively mild microclimate for Arctic plants and animals, and it also determines the water content of the snowpack (snow water equivalent) important for e.g. hydrological applications. Analysis of the snow stratigraphy data, divided into three consecutive time periods, show that there has been a change in the last time period. The variable most affected is the snow layer hardness, which shows an increase in hardness of the snowpack. The number of observations with a very hard snow layer/ice at ground level increased three-fold between the first two time periods and the last time period. The thickness of the bottom layer in the snowpack is also highly affected. There has been a 60% increase in layers thinner than 10 cm in the last time period, resulting in a mean reduction in the thickness of the bottom layer from 14 cm to 11 cm. Hence the living conditions for plants and animals at the ground surface have been highly changed. The changes in the snowpack are correlated to an increased mean winter air temperature. Thus, continued increasing, or temperatures within the same ranges as in the last time period, is likely to create harder snow condition in the future. These changes are likely to affect animals that live under the snow such as lemmings and voles or animals that graze sub-Arctic vegetation in winter (e.g. reindeer that would potentially require increased supplementary feeding that incurs financial costs to Sami reindeer herders). Any decrease

  12. 50 years of fusion research

    NASA Astrophysics Data System (ADS)

    Meade, Dale

    2010-01-01

    Fusion energy research began in the early 1950s as scientists worked to harness the awesome power of the atom for peaceful purposes. There was early optimism for a quick solution for fusion energy as there had been for fission. However, this was soon tempered by reality as the difficulty of producing and confining fusion fuel at temperatures of 100 million °C in the laboratory was appreciated. Fusion research has followed two main paths—inertial confinement fusion and magnetic confinement fusion. Over the past 50 years, there has been remarkable progress with both approaches, and now each has a solid technical foundation that has led to the construction of major facilities that are aimed at demonstrating fusion energy producing plasmas.

  13. 50 years of Global Seismic Observations

    NASA Astrophysics Data System (ADS)

    Anderson, K. R.; Butler, R.; Berger, J.; Davis, P.; Derr, J.; Gee, L.; Hutt, C. R.; Leith, W. S.; Park, J. J.

    2007-12-01

    Seismological recordings have been made on Earth for hundreds of years in some form or another, however, global monitoring of earthquakes only began in the 1890's when John Milne created 40 seismic observatories to measure the waves from these events. Shortly after the International Geophysical Year (IGY), a concerted effort was made to establish and maintain a more modern standardized seismic network on the global scale. In the early 1960's, the World-Wide Standardized Seismograph Network (WWSSN) was established through funding from the Advanced Research Projects Agency (ARPA) and was installed and maintained by the USGS's Albuquerque Seismological Laboratory (then a part of the US Coast and Geodetic Survey). This network of identical seismic instruments consisted of 120 stations in 60 countries. Although the network was motivated by nuclear test monitoring, the WWSSN facilitated numerous advances in observational seismology. From the IGY to the present, the network has been upgraded (High-Gain Long-Period Seismograph Network, Seismic Research Observatories, Digital WWSSN, Global Telemetered Seismograph Network, etc.) and expanded (International Deployment of Accelerometers, US National Seismic Network, China Digital Seismograph Network, Joint Seismic Project, etc.), bringing the modern day Global Seismographic Network (GSN) to a current state of approximately 150 stations. The GSN consists of state-of-the-art very broadband seismic transducers, continuous power and communications, and ancillary sensors including geodetic, geomagnetic, microbarographic, meteorological and other related instrumentation. Beyond the GSN, the system of global network observatories includes contributions from other international partners (e.g., GEOSCOPE, GEOFON, MEDNET, F-Net, CTBTO), forming an even larger backbone of permanent seismological observatories as a part of the International Federation of Digital Seismograph Networks. 50 years of seismic network operations have provided

  14. New times of minimum and a period study for GO Cygni

    NASA Technical Reports Server (NTRS)

    Hall, Douglas S.; Louth, Howard

    1990-01-01

    Times of minimum derived from photometry obtained in 1963, 1967, 1978, and 1979 are presented. With these and previously published times, the period is studied. A constant period increase (quadratic ephemeris) represents most of the times but there was a period decrease in 1934 and possibly in 1984. A 50-year magnetic cycle is discussed.

  15. Child protection: a 50-year perspective.

    PubMed

    Skellern, Catherine Yvette

    2015-01-01

    It has been 50 years since Kempe et al. published 'The Battered Child Syndrome', describing harm from inflicted injury mechanisms derived from parents and care givers. Since then, there has emerged a rapidly expanding literature on paediatric forensic medicine and child protection, which has offered new insights into injury mechanisms, informed us of the sequelae of abuse and neglect, aided diagnosis and guided clinical practice in the treatment and management of children who become involved in the child protection system. Through the scrutiny of government inquiries and at times uncomfortable media exposure, there have been improvements in child protection and forensic practices resulting in recognition of need for specialised forensic training, improved funding, development of resources and development of professional standards that support accountable, objective, safe and robust practice. From the perspective of an Australian child protection paediatrician, this paper chronicles some of the most significant and at times controversial research in the last 50 years in child protection that have played a key role in shaping our current understanding of child abuse and neglect. PMID:25534472

  16. 50 years of holographic interferometry

    NASA Astrophysics Data System (ADS)

    Stetson, Karl A.

    2015-01-01

    Fifty years ago, Robert L. Powell and I discovered holographic interferometry while working at the Radar Laboratory of the University of Michigan's Institute of Science and Technology. I have worked in this field for this entire time span, watched it grow from an unexplored technology to become a widespread industrial testing method, and I have contributed to these developments. In this paper, I will trace my history in this field from our discovery to my involvement in its theory and applications. I will conclude with a discussion of digital holography, which is currently replacing photographic holography for most research and industrial applications.

  17. Looking back 50 years in hospital administration.

    PubMed

    Graham, Ross; Sibbald, Shannon L

    2012-01-01

    Healthcare policy and hospital administration are dynamic and growing fields, oriented toward shaping the future. In an effort to understand where these fields have come from, as well as some of the re-occuring challenges faced, we conducted a retrospective analysis. Our research identified progress and major accomplishments, as well as issues that continue to challenge the field in five key areas: (1) the evolution of nursing, (2) funding and legislation, (3) hospital design, construction and technology, (4) patient care and infection control and (5) leadership. To explore these areas, a thematic content review was conducted on the 12 inaugural issues of Hospital Administration in Canada, a hospital administration periodical from 1962. All written content was reviewed, coded and categorized into major themes that represented the major hospital administration topics of 50 years ago. In this article, five prominent themes are explored and further illustrated using key stories and milestones from 1962. PMID:23107901

  18. Incorporating Spectra Into Periodic Timing

    NASA Astrophysics Data System (ADS)

    Connors, Alanna; Hong, J.; Protopapas, P.; Kashyap, V.

    2011-09-01

    The Chandra surveys have resulted in a wealth of data on low-luminosity X-ray sources (Lx 1030-34 erg/s) of Galactic scales beyond the local solar neighborhood. Many of these are compact binaries, in particular, cataclysmic variables, often identified by their periodic X-ray variability and spectra. Hong et al. (2009, 2011) have used energy quantiles (Hong, Schlegel & Grindlay, 2004) as a fast, robust indicator of spectral hardness and absorption of the X-ray sources. Energy quantiles also enable a simple but effective illustration of spectral changes with phase in these periodic systems: e.g. absorption by the accreting material is understood to drive the periodic light-curves. An interesting question is how to best make use of the information encapsulated in the periodic change in energy spectrum, along with the periodic change in intensity, especially for cases of ambiguous period determination? And, how to do it computationally efficiently? A first approach is to do the period search in intensity, as is standard; and then use a criterion of spectral variation to verify possible periods. Huijse, Zegers & Protopapas (2011) recently demonstrated a powerful period estimation technique using information potential and correntropy embedded in the light curve. Similar quantities based on energies (or energy quantiles) of X-ray photons can serve as criteria of spectral variation. A different approach treats the spectrum variations and intensity variations completely independently, searching through period-space in each, and then combining the results. A more general method would include both at the same time, looking for statistically significant variations above what is expected for a constant (in intensity and spectrum).

  19. Celebrating 50 Years of Laser

    SciTech Connect

    Rebel, Heinigerd

    2010-11-24

    When thinking of an innovation that has truly changed our world, it is the laser. Right after discovery back in 1960, it is immediately propelled to a public star. People loved the mystery around this new kind of light. It was soon recognized as a symbol of our entry into the future: The Laser Age has started. Newspapers speculated about ''death rays'' as new weapons. It did not take long time until it appeared in Science fiction movies. However reality was much more beneficial and even more diverse. This device has managed to exceed the wildest predictions of the early laser pioneers when it comes to its applications. Today lasers are not a weird scientist's toy, but are commonly used in our everyday life.Of course, nothing of that was foreseen in the early 1950s. Important fundamentals of lasers have been laid already in 1917 by Albert Einstein, introducing the Einstein coefficient of stimulated emission, and subsequent experimental work by Rudolf Ladenburg, Willis Lamb, Alfred Kastler and others.

  20. Celebrating 50 Years of Laser

    NASA Astrophysics Data System (ADS)

    Rebel, Heinigerd

    2010-11-01

    When thinking of an innovation that has truly changed our world, it is the laser. Right after discovery back in 1960, it is immediately propelled to a public star. People loved the mystery around this new kind of light. It was soon recognized as a symbol of our entry into the future: The Laser Age has started. Newspapers speculated about ``death rays'' as new weapons. It did not take long time until it appeared in Science fiction movies. However reality was much more beneficial and even more diverse. This device has managed to exceed the wildest predictions of the early laser pioneers when it comes to its applications. Today lasers are not a weird scientist's toy, but are commonly used in our everyday life. Of course, nothing of that was foreseen in the early 1950s. Important fundamentals of lasers have been laid already in 1917 by Albert Einstein, introducing the Einstein coefficient of stimulated emission, and subsequent experimental work by Rudolf Ladenburg, Willis Lamb, Alfred Kastler and others.

  1. Marshall Space Flight Center: 50 Years, 50 Seconds

    NASA Video Gallery

    Talk about time flying! Take a look at this super-fast review of highlights from the past 50 years at the Marshall Center. This year, Marshall is celebrating its 50th anniversary, highlighting its ...

  2. 43 CFR 10010.45 - Time periods.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Time periods. 10010.45 Section 10010.45... Environmental Impact Statements § 10010.45 Time periods. (a) The minimum review period for a draft EIS will be... proposed reductions in time periods or any extensions of time periods proposed by those agencies....

  3. 43 CFR 10010.45 - Time periods.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Time periods. 10010.45 Section 10010.45... Environmental Impact Statements § 10010.45 Time periods. (a) The minimum review period for a draft EIS will be... proposed reductions in time periods or any extensions of time periods proposed by those agencies....

  4. 43 CFR 10010.45 - Time periods.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Time periods. 10010.45 Section 10010.45... Environmental Impact Statements § 10010.45 Time periods. (a) The minimum review period for a draft EIS will be... proposed reductions in time periods or any extensions of time periods proposed by those agencies....

  5. 43 CFR 10010.45 - Time periods.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Time periods. 10010.45 Section 10010.45... Environmental Impact Statements § 10010.45 Time periods. (a) The minimum review period for a draft EIS will be... proposed reductions in time periods or any extensions of time periods proposed by those agencies....

  6. 50 years of membership in AGU recognized

    NASA Astrophysics Data System (ADS)

    Recently, 14 AGU members who joined the Union in 1937 received their recognition pins for 50 years of membership in the Union. They join the distinguished ranks of the 50- year AGU members, who are listed below by the year that they joined:1937 A.B. Bryan, Leonard B. Corwin, Tate Dalrymple, Richard H. Fleming, Harry L. Frauenthal, Konrad B. Krauskopf, J. Stuart Meyers, Brian O'Brien, Joseph F. Poland, Edward J. Rutter, Noel H. Stearn, John P. Tully, Victor Vacquier, G.H. Westby, and Harvey O. Westby.

  7. Ned Greenberg: 50 Years and Counting | Poster

    Cancer.gov

    By Ashley DeVine, Staff Writer Can you imagine working for the same company for 50 years? Nathaniel “Ned” Greenberg has accomplished just that, having recently received his 50-year service award from NIH, and he has no immediate plans for retirement. “I don’t look upon my job as a chore, it’s more of an avocation than a vocation,” said Greenberg, a chemist in the Biological Testing Branch (BTB), under Branch Chief Melinda Hollingshead, DVM, Ph.D. “I am lucky that I found something that I enjoy doing.”

  8. The Business Schools: 50 Years on

    ERIC Educational Resources Information Center

    Clarke, Thomas

    2008-01-01

    Purpose: This paper aims to offer a critique of the development of university business schools over the last 50 years and provide a perspective on the occasion of the 50th anniversary of the publication of the journal Education + Training. Design/methodology/approach: The approach is critical and reflexive, reviewing the historical growth of…

  9. 50 years of mass balance observations at Vernagtferner, Eastern Alps

    NASA Astrophysics Data System (ADS)

    Braun, Ludwig; Mayer, Christoph

    2016-04-01

    The determination and monitoring of the seasonal and annual glacier mass balances of Vernagtferner, Austria, started in 1964 by the Commission of Glaciology, Bavarian Academy of Sciences. Detailed and continuous climate- and runoff measurements complement this mass balance series since 1974. Vernagtferner attracted the attention of scientists since the beginning of the 17th century due to its rapid advances and the resulting glacier lake outburst floods in the Ötztal valley. This is one reason for the first photogrammetric survey in 1889, which was followed by frequent topographic surveys, adding up to more than ten digital elevation models of the glacier until today. By including the known maximum glacier extent at the end of the Little Ice Age in 1845, the geodetic glacier volume balances cover a time span of almost 170 years. The 50 years of glacier mass balance and 40 years of water balance in the drainage basin are therefore embedded in a considerably longer period of glacier evolution, allowing an interpretation within an extended frame of climatology and ice dynamics. The direct mass balance observations cover not only the period of alpine-wide strong glacier mass loss since the beginning of the 1990s. The data also contain the last period of glacier advances between 1970 and 1990. The combination of the observed surface mass exchange and the determined periodic volumetric changes allows a detailed analysis of the dynamic reaction of the glacier over the period of half a century. The accompanying meteorological observations are the basis for relating these reactions to the climatic changes during this period. Vernagtferner is therefore one of the few glaciers in the world, where a very detailed glacier-climate reaction was observed for many decades and can be realistically reconstructed back to the end of the Little Ice Age.

  10. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Time periods. 58.21 Section 58.21...: Environmental Review Procedures § 58.21 Time periods. All time periods in this part shall be counted in calendar days. The first day of a time period begins at 12:01 a.m. local time on the day following...

  11. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Time periods. 58.21 Section 58.21...: Environmental Review Procedures § 58.21 Time periods. All time periods in this part shall be counted in calendar days. The first day of a time period begins at 12:01 a.m. local time on the day following...

  12. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 1 2014-04-01 2014-04-01 false Time periods. 58.21 Section 58.21...: Environmental Review Procedures § 58.21 Time periods. All time periods in this part shall be counted in calendar days. The first day of a time period begins at 12:01 a.m. local time on the day following...

  13. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 1 2012-04-01 2012-04-01 false Time periods. 58.21 Section 58.21...: Environmental Review Procedures § 58.21 Time periods. All time periods in this part shall be counted in calendar days. The first day of a time period begins at 12:01 a.m. local time on the day following...

  14. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 1 2013-04-01 2013-04-01 false Time periods. 58.21 Section 58.21...: Environmental Review Procedures § 58.21 Time periods. All time periods in this part shall be counted in calendar days. The first day of a time period begins at 12:01 a.m. local time on the day following...

  15. Paediatric infectious diseases: the last 50 years.

    PubMed

    Starr, Mike

    2015-01-01

    Many advances and challenges have occurred in the field of paediatric infectious diseases during the past 50 years. It is impossible to cover all of these in a short review, but a few highlights and lowlights will be covered. These include virtual disappearance of some infectious diseases, emergence of new ones, infections in the immunocompromised, antimicrobial resistance, development of new and improved antimicrobials, improved diagnostic tests and the Human Microbiome Project. PMID:25557805

  16. The Kerr Metric: 50 Years Later

    NASA Astrophysics Data System (ADS)

    Teukolsky, Saul

    2015-04-01

    I will describe the events leading up to the discovery of the Kerr metric in 1963 and the enormous impact the discovery has had in the subsequent 50 years. The talk will emphasize the ``miraculous'' nature of the solution, both as a simple analytic formula describing the most general rotating black hole, and as having unexpected mathematical properties that make many calculations tractable. Supported in part by NSF Grants PHY-1306125 and No. AST-1333129 at Cornell University, and by a grant from the Sherman Fairchild Foundation.

  17. 50 years of radiation research: medicine.

    PubMed

    Phillips, Theodore L

    2002-10-01

    The advances brought about by research in radiation medicine over the past 50 years are presented. The era began with the atomic explosions in Hiroshima and Nagasaki and the establishment of the Atomic Bomb Casualty Commission to understand what damage was caused by exposure of a large population to radiation. A better understanding of the effects of whole-body exposure led to the development of whole-body radiation treatment techniques and to bone marrow transplantation in the treatment of leukemias. The field of diagnostic imaging was revolutionized by a series of inventions that included angiography, mammography, computed tomography, magnetic resonance imaging, magnetic resonance spectroscopy, and ultrasound imaging. The field of nuclear medicine came of age through new man-made radionuclides and the invention of scanning and imaging techniques including positron emission tomography. Radiotherapy, a minor sideline of radiology, developed into radiation oncology, an extremely important component of modern cancer therapy. The advances in clinical radiotherapy were made possible by discoveries and inventions in physics and engineering and by insights and discoveries in radiobiology. The result of the last 50 years of progress is a very powerful set of clinical tools. PMID:12236808

  18. Ceremony celebrates 50 years of rocket launches

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Ceremony celebrates 50 years of rocket launches PL00C-10364.12 At the 50th anniversary ceremony celebrating the first rocket launch from pad 3 on what is now Cape Canaveral Air Force Station, Norris Gray waves to the audience. Gray was part of the team who successfully launched the first rocket, known as Bumper 8. The ceremony was hosted by the Air Force Space & Missile Museum Foundation, Inc. , and included launch of a Bumper 8 model rocket, presentation of a Bumper Award to Florida Sen. George Kirkpatrick by the National Space Club; plus remarks by Sen. Kirkpatrick, KSC's Center Director Roy Bridges, and the Commander of the 45th Space Wing, Brig. Gen. Donald Pettit. Also attending the ceremony were other members of the original Bumper 8 team. A reception followed at Hangar C. Since 1950 there have been a total of 3,245 launches from Cape Canaveral.

  19. [Medical research ethics 50 years after Nuremberg].

    PubMed

    Ruyter, K W

    1997-12-10

    50 years ago, in Nuremberg, 23 German doctors were accused of crimes against humanity. The anniversary is a solemn reminder of the dark origins of medical research ethics. Many researchers today believe that the medical experiments carried out under Hitler "vaccinated" postwar researchers against abuse. A review of the practices of postwar research shows that the "vaccination" had limited effect and that there is no reason to believe that the events which took place under Hitler were unique and will never happen again. After the war various measures were introduced to protect research subjects: informed consent, self regulation and independent research ethics committees. The measures have undoubtedly limited the abuse of subjects substantially. Nevertheless, in the Armed Forces, where abuse has been most rampant after the war, informed consent is not always practised and independent review is seldom carried out. With the support of grant institutions, journals and industry the protection of research subjects can be improved. It is recommended that medical faculties arrange an annual commemoration of the victims of medical research in order to raise consciousness and awareness among teachers and students. PMID:9456583

  20. Proportional mortality of 50 years and above

    PubMed Central

    Swaroop, S.; Uemura, K.

    1957-01-01

    In 1954 the United Nations Committee of Experts on International Definition and Measurement of Standards and Levels of Living suggested that for the measurement of levels of living quantifiable or potentially quantifiable components should be considered separately. An attempt is made in the present paper to evolve a single, comprehensive numerical indicator to quantify the component “health, including demographic conditions”. The use of an objective statistical technique as a guide in the selection of such an indicator is suggested. From the application of this technique, it is concluded that the percentage of deaths at the ages 50 years and over to total deaths (proportional mortality) affords a fairly suitable yardstick by which broad inter-country comparisons may be made. This indicator has the advantages of simplicity of calculation, comprehensiveness, availability of data, possibility of international comparability despite the varying quality of basic statistical information, sensitivity for the purpose of inter-country comparisons, and validity for studying levels and trends. PMID:13500159

  1. How Sensitively Timed Are Sensitive Periods?

    ERIC Educational Resources Information Center

    Zener, Rita Schaefer

    2003-01-01

    Reviews Maria Montessori's view of sensitive periods and examines the kinds of help needed from adults: an open mind, specific help from a prepared learning environment, and challenges presented at the right time. Stresses the universality of sensitive periods and their connection to brain development. Focuses on the unconscious nature and…

  2. Launchers - The first 50-year cycle

    NASA Astrophysics Data System (ADS)

    Pardoe, G. K. C.

    1986-11-01

    An assessment is made of the development history of spacecraft launch vehicles to the present date, with attention to mission economics and the criteria of profitability. Three technological generations are postulated: that dominated by expendable launch vehicles, lasting from 1957 to the introduction of the Space Shuttle; the Space Shuttle period of semireusable launch vehicles; and the soon-to-be-inaugurated era of fully reusable launchers which are expected to begin operations around the year 2000.

  3. Instability of time-periodic flows

    NASA Technical Reports Server (NTRS)

    Hall, P.

    1985-01-01

    The instabilities of some spatially and/or time-periodic flows are discussed, in particular, flows with curved streamlines which can support Taylor-Gortler vortices are described in detail. The simplest flow where this type of instability can occur is that due to the torsional oscillations of an infinitely long circular cylinder. For more complicated spatially varying time-periodic flows, a similar type of instability can occur and is spatially localized near the most unstable positions. When nonlinear effects are considered it is found that the instability modifies the steady streaming boundary layer induced by the oscillatory motion. It is shown that a rapidly rotating cylinder in a uniform flow is susceptible to a related type of instability; the appropriate stability equations are shown to be identical to those which govern the instability of a boussinesq fluid of Prandtl number unity heated time periodically from below.

  4. Comparison of 50-year and 70-year internal-dose-conversion factors

    SciTech Connect

    Ryan, M.T.; Dunning, D.E. Jr.

    1981-03-01

    The 50-year inhalation and ingestion dose commitments associated with an acute intake (of a radionuclide) of 3.7 x 10/sup 4/ Bq (1 ..mu..Ci) in one day were compared with the corresponding dose commitments calculated for a 70-year integration period resulting from a chronic intake of the same amount at a rate of 101 Bq/d (0.00274 ..mu..Ci/d) for one year. These values, known as dose conversion factors, estimate the dose accumulated during a given period of time following a unit of intake of a radionuclide. It was demonstrated that the acute intake of 3.7 x 10/sup 4/ Bq in one day and the chronic intake of 101 Bq/d for one year (a total intake of 3.7 x 10/sup 4/ Bq) result in essentially the same dose commitment for a relatively long integration period. Therefore, the comparison of 50-year acute dose conversion factors and 70-year chronic dose conversion factors is essentially only a measure of the additional dose accumulated in the 50 to 70 year period. It was found that for radionuclides with atomic mass less than 200 the percent difference in the 70-year and 50-year dose conversion factors was essentially zero in most cases. Differences of approximately 5 to 50% were obtained for dose conversion factors for most alpha emitters with atomic masses of greater than 200. Comparisons were made on the basis of both organ dose equivalent and effective dose equivalent. The implications and significance of these results are discussed.

  5. A New Minority 50 Years after "Brown"

    ERIC Educational Resources Information Center

    Hardy, Lawrence

    2004-01-01

    Legal segregation might be dead, but many metropolitan schools remain overwhelmingly black and poor--a result of years of white flight from central cities and recent court decisions accelerating a return to neighborhood schools. At the same time, the bourgeoning Hispanic population is finding itself in increasingly segregated schools across the…

  6. The First 50 Years of Konkoly Observatory

    NASA Astrophysics Data System (ADS)

    Balazs, Lajos G.; Vargha, Magda; Zsoldos, Endre

    The second half of the 19th century experienced a revolution in astronomy. It coincided with a new start of professional astronomy in Hungary through the work of Miklós Konkoly Thege (1842-1916) who is considered as a pioneer of current astrophysical activity in our country. He played an outstanding role in organizing scientific life and institutions, too. He started observations in his newly founded Observatory at Ógyalla in 1871. Sunspots were regularly observed in the observatory from 1872. In 1874 Konkoly began regular spectroscopic observations of comets and emphasized the importance of parallel laboratory works. An important field of Konkoly's astronomical activity was the observation of surface patterns of planets, particularly that of Jupiter and Mars. Spectroscopic observations of stars were also a significant part of the activity of Ógyalla Observatory. In the last period of the Konkoly era (starting in 1899) stellar photometry became the main field of research. At the end of WW I the institute was moved to Budapest Ógyalla and started a new life based on a completely new infrastructure: “... all era are followed by a new one, with its new tasks, in which the scope of activity changes correspondingly, in which enthusiasm is mostly manifested. It was different in the forties when our nation found itself following the word of the founder of our Academy, it was different in the fifties and sixties when we have to defend our nation against foreign aggression, and it became different since the sixties when, our existence being guarantied, we also have to make an effort, beside strengthening it, to get as distinguished a position among the civilized nations as possible.”

  7. Plague reappearance in Algeria after 50 years, 2003.

    PubMed

    Bertherat, Eric; Bekhoucha, Souad; Chougrani, Saada; Razik, Fathia; Duchemin, Jean B; Houti, Leila; Deharib, Larbi; Fayolle, Corinne; Makrerougrass, Banaouda; Dali-Yahia, Radia; Bellal, Ramdan; Belhabri, Leila; Chaieb, Amina; Tikhomirov, Evgueni; Carniel, Elisabeth

    2007-10-01

    An outbreak of plague occurred in the region of Oran, Algeria, from June to July 2003. Algeria had not reported this disease for >50 years. Eighteen bubonic cases were identified, and Yersinia pestis was isolated from 6 patients. Except for the index case-patient, all patients recovered. Targeted chemoprophylaxis, sanitation, and vector control played a crucial role in controlling the outbreak. Epidemiologic and biomolecular findings strongly suggested the existence of a local animal reservoir during this period, but its origin (resurgence or re-importation) could not be determined. This sudden and unexpected reemergence of plague, close to an important commercial seaport, is a textbook illustration of a public health event of international importance. It also demonstrates that the danger of plague reoccurrence is not limited to the currently indexed natural foci. PMID:18257987

  8. Plague Reappearance in Algeria after 50 Years, 2003

    PubMed Central

    Bekhoucha, Souad; Chougrani, Saada; Razik, Fathia; Duchemin, Jean B.; Houti, Leila; Deharib, Larbi; Fayolle, Corinne; Makrerougrass, Banaouda; Dali-Yahia, Radia; Bellal, Ramdan; Belhabri, Leila; Chaieb, Amina; Tikhomirov, Evgueni; Carniel, Elisabeth

    2007-01-01

    An outbreak of plague occurred in the region of Oran, Algeria, from June to July 2003. Algeria had not reported this disease for >50 years. Eighteen bubonic cases were identified, and Yersinia pestis was isolated from 6 patients. Except for the index case-patient, all patients recovered. Targeted chemoprophylaxis, sanitation, and vector control played a crucial role in controlling the outbreak. Epidemiologic and biomolecular findings strongly suggested the existence of a local animal reservoir during this period, but its origin (resurgence or re-importation) could not be determined. This sudden and unexpected reemergence of plague, close to an important commercial seaport, is a textbook illustration of a public health event of international importance. It also demonstrates that the danger of plague reoccurrence is not limited to the currently indexed natural foci. PMID:18257987

  9. Pennsylvanian time scales and cycle periods

    SciTech Connect

    deV. Klein, G. )

    1990-05-01

    Geochronological results from central Europe indicate that the duration of Pennsylvanian time is only 19 m.y., compared to the Harland et al. and Palmer estimates of 34 m.y. Prior calculations of Pennsylvanian cycle periods from the midcontinent of North America suggesting a fit with Milankovitch orbital parameters may well be in errors; as a consequence, other mechanisms for possible eustatic sea-level changes represented in those cycles are needed. Calculation of cycle periods of 100 ka or less lack precision in stratigraphic intervals representing ages characterized by error margins of millions of years. Thus, cycle periods may be less reliable as an indicator of global process than previously considered, particularly in rocks of Paleozoic and early and middle Mesozoic age.

  10. Oscillator Phase Noise: A 50-Year Review.

    PubMed

    Leeson, David B

    2016-08-01

    Fifty years ago emerging requirements in oscillator applications led to the 1964 IEEE-NASA Symposium on Short-term Frequency Stability. Following that, IEEE Technical Committee 14.7 was established to unify time- and frequency-domain definitions of frequency stability. I had the good fortune to participate and contribute as a member of the symposium program committee and the IEEE committee. This paper is a personal retrospective of events that are said to have shaped our field: the 1964 Symposium, the 1966 Proc. IEEE special issue on frequency stability we edited (with comments on my oscillator-model paper), and our 1971 paper, "Characterization of Frequency Stability," written as a basis for IEEE STD 1139. PMID:27164585

  11. Food transitions in last 50 years and related environmental implications

    NASA Astrophysics Data System (ADS)

    Pradhan, P.; Reusser, D. E.; Kropp, J. P.

    2012-04-01

    Food production is an important driver for global change processes such as land use change and green-house-gas emissions. We analyzed a global, long term data set on food consumption per country to identify typical patterns of diets for the last 50 years. From changes in these patterns, we derived food transitions on a global scale. Subsequently we assessed the environmental consequences from green-house-gas (GHG) emission and anthropogenic inputs. More specifically, we applied Self Organizing Maps (SOM) to identify the dietary patterns based on supply of 12 food groups from FAOSTAT dataset for a period 1961-2007. Using the data on energy output/input ratio for crop production and agricultural emission, we estimated fossil energy and GHG emission associated with the diets. We found 16 typical consumption patterns consisting of high, moderate, low and lowest calorie supply with varied food compositions. The high calorie diets are associated with a higher supply of cereals, animal-products, vegetable-oils and sugar-sweeteners featuring a total supply greater than 2800 kcal/cap/day. During the last 50 years, we observed food transitions from lower calories diets to higher calories diets. On the one hand, food transition towards affluent diet, sometime with shortcuts, occurred in developing countries. On the other hand, developed countries increased consumption of fruits and vegetables. Some of the developing countries are also stagnated in the low consumption level during the last 50 years. The high calorie diets also embed higher fossil energy (1800-3500 kcal/cap/day) and are associated with higher GHG emissions (3.7-6.1 kg CO2 eq/cap/day). However, their non-CO2 GHG emission intensities per kilo calorie of food are relatively low. Changes in dietary patterns are a part of the global change processes. Identification of past transitions is way to predict possible future transitions. This in turn supports policy processes and negotiations in the fields of climate

  12. Analysis of the time scales in time periodic Darcy flows

    NASA Astrophysics Data System (ADS)

    Zhu, T.; Waluga, C.; Wohlmuth, B.; Manhart, M.

    2014-12-01

    We investigate unsteady flow in a porous medium under time - periodic (sinusoidal) pressure gradient. DNS were performed to benchmark the analytical solution of the unsteady Darcy equation with two different expressions of the time scale : one given by a consistent volume averaging of the Navier - Stokes equation [1] with a steady state closure for the flow resistance term, another given by volume averaging of the kinetic energy equation [2] with a closure for the dissipation rate . For small and medium frequencies, the analytical solutions with the time scale obtained by the energy approach compare well with the DNS results in terms of amplitude and phase lag. For large frequencies (f > 100 [Hz]) we observe a slightly smaller damping of the amplitude. This study supports the use of the unsteady form of Darcy's equation with constant coefficients to solve time - periodic Darcy flows at low and medium frequencies. Our DNS simulations, however, indicate that the time scale predicted by the VANS approach together with a steady - state closure for the flow resistance term is too small. The one obtained by the energy approach matches the DNS results well. At large frequencies, the amplitudes deviate slightly from the analytical solution of the unsteady Darcy equation. Note that at those high frequencies, the flow amplitudes remain below 1% of those of steady state flow. This result indicates that unsteady porous media flow can approximately be described by the unsteady Darcy equation with constant coefficients for a large range of frequencies, provided, the proper time scale has been found.

  13. AIDS in adults 50 years of age and over: characteristics, trends and spatial distribution of the risk1

    PubMed Central

    Nogueira, Jordana de Almeida; Silva, Antônia Oliveira; de Sá, Laísa Ribeiro; de Almeida, Sandra Aparecida; Monroe, Aline Aparecida; Villa, Tereza Cristina Scatena

    2014-01-01

    Objective to analyze the sociodemographic characteristics, epidemic trend and spatial distribution of the risk of AIDS in adults 50 years of age and over. Method population-based, ecological study, that used secondary data from the Notifiable Disease Information System (Sinan/AIDS) of Paraíba state from the period January 2000 to December 2010. Results during the study period, 307 cases of AIDS were reported among people 50 years of age or over. There was a predominance of males (205/66, 8%), mixed race, and low education levels. The municipalities with populations above 100 thousand inhabitants reported 58.5% of the cases. There was a progressive increase in cases among women; an increasing trend in the incidence (positive linear correlation); and an advance in the geographical spread of the disease, with expansion to the coastal region and to the interior of the state, reaching municipalities with populations below 30 thousand inhabitants. In some locations the risk of disease was 100 times greater than the relative risk for the state. Conclusion aging, with the feminization and interiorization of the epidemic in adults 50 years of age and over, confirms the need for the induction of affirmative policies targeted toward this age group. PMID:25029044

  14. Has adult sleep duration declined over the last 50+ years?

    PubMed

    Youngstedt, Shawn D; Goff, Eric E; Reynolds, Alexandria M; Kripke, Daniel F; Irwin, Michael R; Bootzin, Richard R; Khan, Nidha; Jean-Louis, Girardin

    2016-08-01

    The common assumption that population sleep duration has declined in the past few decades has not been supported by recent reviews, which have been limited to self-reported data. The aim of this review was to assess whether there has been a reduction in objectively recorded sleep duration over the last 50+ years. The literature was searched for studies published from 1960 to 2013, which assessed objective sleep duration (total sleep time (TST)) in healthy normal-sleeping adults. The search found 168 studies that met inclusion criteria, with 257 data points representing 6052 individuals ages 18-88 y. Data were assessed by comparing the regression lines of age vs. TST in studies conducted between 1960 and 1989 vs. 1990-2013. Weighted regression analyses assessed the association of year of study with age-adjusted TST across all data points. Regression analyses also assessed the association of year of study with TST separately for 10-y age categories (e.g., ages 18-27 y), and separately for polysomnographic and actigraphic data, and for studies involving a fixed sleep schedule and participants' customary sleep schedules. Analyses revealed no significant association of sleep duration with study year. The results are consistent with recent reviews of subjective data, which have challenged the notion of a modern epidemic of insufficient sleep. PMID:26478985

  15. A Dynamic Earth: 50 Years of Observations from Space

    NASA Technical Reports Server (NTRS)

    Evans, Cynthia A.

    2013-01-01

    Observations of the surface of the Earth began more than a half century ago with the earliest space missions. The global geopolitical environment at the beginning of the space age fueled advances in rocketry and human exploration, but also advances in remote sensing. At the same time that space-based Earth Observations were developing, global investments in infrastructure that were initiated after World War II accelerated large projects such as the construction of highways, the expansion of cities and suburbs, the damming of rivers, and the growth of big agriculture. These developments have transformed the Earth s surface at unprecedented rates. Today, we have a remarkable library of 50 years of observations of the Earth taken by satellite-based sensors and astronauts, and these images and observations provide insight into the workings of the Earth as a system. In addition, these observations record the footprints of human activities around the world, and illustrate how our activities contribute to the changing face of the Earth. Starting with the iconic "Blue Marble" image of the whole Earth taken by Apollo astronauts, we will review a timeline of observations of our planet as viewed from space.

  16. Approved Antiviral Drugs over the Past 50 Years.

    PubMed

    De Clercq, Erik; Li, Guangdi

    2016-07-01

    Since the first antiviral drug, idoxuridine, was approved in 1963, 90 antiviral drugs categorized into 13 functional groups have been formally approved for the treatment of the following 9 human infectious diseases: (i) HIV infections (protease inhibitors, integrase inhibitors, entry inhibitors, nucleoside reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors, and acyclic nucleoside phosphonate analogues), (ii) hepatitis B virus (HBV) infections (lamivudine, interferons, nucleoside analogues, and acyclic nucleoside phosphonate analogues), (iii) hepatitis C virus (HCV) infections (ribavirin, interferons, NS3/4A protease inhibitors, NS5A inhibitors, and NS5B polymerase inhibitors), (iv) herpesvirus infections (5-substituted 2'-deoxyuridine analogues, entry inhibitors, nucleoside analogues, pyrophosphate analogues, and acyclic guanosine analogues), (v) influenza virus infections (ribavirin, matrix 2 protein inhibitors, RNA polymerase inhibitors, and neuraminidase inhibitors), (vi) human cytomegalovirus infections (acyclic guanosine analogues, acyclic nucleoside phosphonate analogues, pyrophosphate analogues, and oligonucleotides), (vii) varicella-zoster virus infections (acyclic guanosine analogues, nucleoside analogues, 5-substituted 2'-deoxyuridine analogues, and antibodies), (viii) respiratory syncytial virus infections (ribavirin and antibodies), and (ix) external anogenital warts caused by human papillomavirus infections (imiquimod, sinecatechins, and podofilox). Here, we present for the first time a comprehensive overview of antiviral drugs approved over the past 50 years, shedding light on the development of effective antiviral treatments against current and emerging infectious diseases worldwide. PMID:27281742

  17. Biogeochemical control of marine productivity in the Mediterranean Sea during the last 50 years

    PubMed Central

    Macias, Diego; Garcia-Gorriz, Elisa; Piroddi, Chiara; Stips, Adolf

    2014-01-01

    The temporal dynamics of biogeochemical variables derived from a coupled 3-D model of the Mediterranean Sea are evaluated for the last 50 years (1960–2010) against independent data on fisheries catch per unit effort (CPUE) for the same time period. Concordant patterns are found in the time series of all of the biological variables (from the model and from fisheries statistics), with low values at the beginning of the series, a later increase, with maximum levels reached at the end of the 1990s, and a posterior stabilization. Spectral analysis of the annual biological time series reveals coincident low-frequency signals in all of them. The first, more energetic signal peaks around the year 2000, while the second, less energetic signal peaks near 1982. Almost identical low-frequency signals are found in the nutrient loads of the rivers and in the integrated nutrient levels in the surface marine ecosystem. Nitrate concentration shows a maximum level in 1998, with a later stabilization to present-day values, coincident with the first low-frequency signal found in the biological series. Phosphate shows maximum concentrations around 1982 and a posterior sharp decline, in concordance with the second low-frequency signal observed in the biological series. That result seems to indicate that the control of marine productivity (plankton to fish) in the Mediterranean is principally mediated through bottom-up processes that could be traced back to the characteristics of riverine discharges. The high sensitivity of CPUE time series to environmental conditions might be another indicator of the overexploitation of this marine ecosystem. Key Points Biogeochemical evolution of the Mediterranean over the past 50 years River nutrient loads drive primary and secondary productions Strong link between low trophic levels and fisheries PMID:26180286

  18. Modified Methodology for Projecting Coastal Louisiana Land Changes over the Next 50 Years

    USGS Publications Warehouse

    Hartley, Steve B.

    2009-01-01

    The coastal Louisiana landscape is continually undergoing geomorphologic changes (in particular, land loss); however, after the 2005 hurricane season, the changes were intensified because of Hurricanes Katrina and Rita. The amount of land loss caused by the 2005 hurricane season was 42 percent (562 km2) of the total land loss (1,329 km2) that was projected for the next 50 years in the Louisiana Coastal Area (LCA), Louisiana Ecosystem Restoration Study. The purpose of this study is to provide information on potential changes to coastal Louisiana by using a revised LCA study methodology. In the revised methodology, we used classified Landsat TM satellite imagery from 1990, 2001, 2004, and 2006 to calculate the 'background' or ambient land-water change rates but divided the Louisiana coastal area differently on the basis of (1) geographic regions ('subprovinces') and (2) specific homogeneous habitat types. Defining polygons by subprovinces (1, Pontchartrain Basin; 2, Barataria Basin; 3, Vermilion/Terrebonne Basins; and 4, the Chenier Plain area) allows for a specific erosion rate to be applied to that area. Further subdividing the provinces by habitat type allows for specific erosion rates for a particular vegetation type to be applied. Our modified methodology resulted in 24 polygons rather than the 183 that were used in the LCA study; further, actively managed areas and the CWPPRA areas were not masked out and dealt with separately as in the LCA study. This revised methodology assumes that erosion rates for habitat types by subprovince are under the influence of similar environmental conditions (sediment depletion, subsidence, and saltwater intrusion). Background change rate for three time periods (1990-2001, 1990-2004, and 1990-2006) were calculated by taking the difference in water or land among each time period and dividing it by the time interval. This calculation gives an annual change rate for each polygon per time period. Change rates for each time period

  19. Tritium in Australian precipitation: A 50 year record

    NASA Astrophysics Data System (ADS)

    Tadros, Carol V.; Hughes, Catherine E.; Crawford, Jagoda; Hollins, Suzanne E.; Chisari, Robert

    2014-05-01

    Tritium in precipitation has been measured in Australia over the past 50 years, as an essential research tool in hydro-climate studies, and to contribute to the Global Network for Isotopes in Precipitation (GNIP). Tritium, a component of the water molecule (HTO), is the only true age tracer for waters. The elevated level of tritium in the environment as a result of last century’s atmospheric thermonuclear testing delivers the benefit of tracing groundwater systems over a 100 year timeframe. The concentration of tritium in Australian precipitation reached a maximum of 160 Tritium Units (TU) in 1963, during one of the most intense periods of nuclear weapons testing. From 1963 to present we observe a rapid drop in the concentration of tritium, more than expected from natural decay, and this can be attributed to the wash out of tritium into the oceans and groundwater. Spikes in the tritium level are superimposed over this general trend; the first around 1969, with levels ranging from 39.4 to 84.4 TU was due to French atmospheric weapon testing, and again in 1990, levels peaked between 6.6 and 12.9 TU, which is attributed to tritium leaking from underground tests in the French Pacific. Since 1990 the levels of tritium have declined globally and regionally. Currently the levels of tritium in Australia are stabilising to around 2-3 TU increasing with latitude across the continent, suggesting that today the tritium in precipitation is predominantly natural. The spatial distribution of tritium is presented and found to be dominated by the annual stratosphere-troposphere exchange in combination with latitude and continental effects. A precipitation amount effect is also observed for inland sites.

  20. Morphological changes of Gumara River channel over 50 years, upper Blue Nile basin, Ethiopia

    NASA Astrophysics Data System (ADS)

    Abate, Mengiste; Nyssen, Jan; Steenhuis, Tammo S.; Moges, Michael M.; Tilahun, Seifu A.; Enku, Temesgen; Adgo, Enyew

    2015-06-01

    In response to anthropogenic disturbances, alluvial rivers adjust their geometry. The alluvial river channels in the upper Blue Nile basin have been disturbed by human-induced factors since a longtime. This paper examines channel adjustment along a 38-km stretch of the Gumara River which drains towards Lake Tana and then to the Blue Nile. Over a 50 years period, agriculture developed rapidly in the catchment and flooding of the alluvial plain has become more frequent in recent times. The objectives of this study were to document the changes in channel planform and cross-section of the Gumara River and to investigate whether the changes could have contributed to the frequent flooding or vice versa. Two sets of aerial photographs (1957 and 1980) were scanned, and then orthorectified. Recent channel planform information was extracted from SPOT images of 2006 and Google Earth. Channel planform and bed morphology (vertical changes) were determined for these nearly 50 years period. The vertical changes were determined based on aggradation along a permanent structure, historic information on river cross-sections at a hydrological gauging station, and field observations. The results indicate that the lower reach of Gumara near its mouth has undergone major planform changes. A delta with approx. 1.12 km2 of emerged land was created between 1957 and 1980 and an additional 1 km2 of land has been added between 1980 and 2006. The sinuosity of the river changed only slightly: negatively (-1.1% i.e. meandering decreased) for the period from 1957 to 1980 and positively (+3.0%) for the period 1980-2006. Comparison of cross-sections at the hydrological gauging station showed that the deepest point in the river bed aggraded by 2.91 m for the period 1963-2009. The importance of sediment deposition in the stream and on its banks is related to land degradation in the upper catchment, and to artificial rising of Lake Tana level that creates a backwater effect and sediment deposition in

  1. Time periodic solution to the compressible Euler equations with damping in a periodic domain

    NASA Astrophysics Data System (ADS)

    Tan, Zhong; Xu, Qiuju; Wang, Huaqiao

    2016-07-01

    In this paper, we consider the existence and uniqueness of a time periodic solution to the three-dimensional compressible damped Euler equations in a periodic domain. By adapting a regularized approximation scheme and applying the topological degree theory, we establish the existence of the time periodic solution under some smallness and structure assumptions imposed on a time periodic force. And based on energy estimates, the uniqueness of the periodic solution is proved.

  2. My 50 years of research in particle physics.

    PubMed

    Sugawara, Hirotaka

    2010-01-01

    Some of my work of the last 50 years in the field of theoretical particle physics is described with particular emphasis on the motivation, the process of investigation, relationship to the work of others, and its impact. My judgment is unavoidably subjective, although I do present the comments of other researchers as much as possible. PMID:20431257

  3. My 50 years of research in particle physics

    PubMed Central

    Sugawara, Hirotaka

    2010-01-01

    Some of my work of the last 50 years in the field of theoretical particle physics is described with particular emphasis on the motivation, the process of investigation, relationship to the work of others, and its impact. My judgment is unavoidably subjective, although I do present the comments of other researchers as much as possible. PMID:20431257

  4. 7 CFR 1.603 - How are time periods computed?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false How are time periods computed? 1.603 Section 1.603 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Conditions in FERC Hydropower Licenses General Provisions § 1.603 How are time periods computed? (a) General. Time periods are...

  5. 7 CFR 1.603 - How are time periods computed?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false How are time periods computed? 1.603 Section 1.603 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Conditions in FERC Hydropower Licenses General Provisions § 1.603 How are time periods computed? (a) General. Time periods are...

  6. 7 CFR 1.603 - How are time periods computed?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 1 2012-01-01 2012-01-01 false How are time periods computed? 1.603 Section 1.603 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Conditions in FERC Hydropower Licenses General Provisions § 1.603 How are time periods computed? (a) General. Time periods are...

  7. 7 CFR 1.603 - How are time periods computed?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false How are time periods computed? 1.603 Section 1.603 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Conditions in FERC Hydropower Licenses General Provisions § 1.603 How are time periods computed? (a) General. Time periods are...

  8. 7 CFR 1.603 - How are time periods computed?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false How are time periods computed? 1.603 Section 1.603 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Conditions in FERC Hydropower Licenses General Provisions § 1.603 How are time periods computed? (a) General. Time periods are...

  9. Fire and Deforestation Dynamics in South America over the Past 50 Years

    NASA Astrophysics Data System (ADS)

    van Marle, M.; Field, R. D.; van der Werf, G.

    2015-12-01

    Fires play an important role in the Earth system and are one of the major sources of greenhouse gases and aerosols. Satellites have been key to understand their spatial and temporal variability in space and time, but the most frequently used satellite datasets start only in 1995. There are still large uncertainties about the frequency and intensity of fires in the pre-satellite time period, especially in regions with active deforestation, which may have changed dramatically in intensity in the past decades influencing fire dynamics. We used two datasets to extend the record of fires and deforestation in the Amazon region back in time: 1) annual forest loss rates starting in 1990 derived from Vegetation Optical Depth (VOD), which is a satellite-based vegetation product that can be used as proxy for forest loss, and 2) horizontal visibility as proxy for fire emissions, reported by weather stations and airports in the Amazon, which started around 1940, and having widespread coverage since 1973. We show that these datasets overlap with fire emission estimates from the Global Fire Emissions Database (GFED) enabling us to estimate fire emissions over the last 50 years. We will discuss how fires have varied over time in this region with globally significant emissions, how droughts have influenced fire activity and deforestation rates, and what the impact is of land-use change caused by fire on emissions in the Amazon region.

  10. An opportune life: 50 years in human cytogenetics.

    PubMed

    Jacobs, Patricia A

    2014-01-01

    This article is one person's view of human cytogenetics over the past 50 years. The flowering of human cytogenetics led the way to the establishment of clinical genetics as one of the most important developments in medicine in the twentieth century. The article is written from the viewpoint of a scientist who never tired of analyzing the images of dividing cells on the light microscope and interpreting the wealth of information contained in them. PMID:25184528

  11. On almost periodic solutions of logistic delay differential equations with almost periodic time dependence

    NASA Astrophysics Data System (ADS)

    Yuan, Rong

    2007-06-01

    In this paper, we study almost periodic logistic delay differential equations. The existence and module of almost periodic solutions are investigated. In particular, we extend some results of Seifert in [G. Seifert, Almost periodic solutions of certain differential equations with piecewise constant delays and almost periodic time dependence, J. Differential Equations 164 (2000) 451-458].

  12. Contact time periods in immunological synapse

    NASA Astrophysics Data System (ADS)

    Bush, Daniel R.; Chattopadhyay, Amit K.

    2014-10-01

    This paper resolves the long standing debate as to the proper time scale <τ> of the onset of the immunological synapse bond, the noncovalent chemical bond defining the immune pathways involving T cells and antigen presenting cells. Results from our model calculations show <τ> to be of the order of seconds instead of minutes. Close to the linearly stable regime, we show that in between the two critical spatial thresholds defined by the integrin:ligand pair (Δ2˜ 40-45 nm) and the T-cell receptor TCR:peptide-major-histocompatibility-complex pMHC bond (Δ1˜ 14-15 nm), <τ> grows monotonically with increasing coreceptor bond length separation δ (= Δ2-Δ1˜ 26-30 nm) while <τ> decays with Δ1 for fixed Δ2. The nonuniversal δ-dependent power-law structure of the probability density function further explains why only the TCR:pMHC bond is a likely candidate to form a stable synapse.

  13. 36 CFR 218.10 - Objection time periods and process.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Objection time periods and... Objection time periods and process. (a) Time to file an objection. Written objections, including any... of objectors to ensure that their objection is received in a timely manner. (b) Computation of...

  14. Student Instruction Should Be Distributed over Long Time Periods

    ERIC Educational Resources Information Center

    Rohrer, Doug

    2015-01-01

    In many academic courses, students encounter a particular fact or concept many times over a period of a few weeks and then do not see it again during the remainder of the course. Are these brief instructional periods sufficient, or should the same amount of instruction be distributed over longer periods of time? This question was the focus of…

  15. Dynamo Sensitivity in Solar Analogs with 50 Years of Ca II H & K Activity

    NASA Astrophysics Data System (ADS)

    Egeland, Ricky; Soon, Willie H.; Baliunas, Sallie L.; Hall, Jeffrey C.; Pevtsov, Alexei A.; Henry, Gregory W.

    2016-05-01

    The Sun has a steady 11-year cycle in magnetic activity most well-known by the rising and falling in the occurrence of dark sunspots on the solar disk in visible bandpasses. The 11-year cycle is also manifest in the variations of emission in the Ca II H & K line cores, due to non-thermal (i.e. magnetic) heating in the lower chromosphere. The large variation in Ca II H & K emission allows for study of the patterns of long-term variability in other stars thanks to synoptic monitoring with the Mount Wilson Observatory HK photometers (1966-2003) and Lowell Observatory Solar-Stellar Spectrograph (1994-present). Overlapping measurements for a set of 27 nearby solar-analog (spectral types G0-G5) stars were used to calibrate the two instruments and construct time series of magnetic activity up to 50 years in length. Precise properties of fundamental importance to the dynamo are available from Hipparcos, the Geneva-Copenhagen Survey, and CHARA interferometry. Using these long time series and measurements of fundamental properties, we do a comparative study of stellar "twins" to explore the sensitivity of the stellar dynamo to small changes to structure, rotation, and composition. We also compare this sample to the Sun and find hints that the regular periodic variability of the solar cycle may be rare among its nearest neighbors in parameter space.

  16. 36 CFR 219.56 - Objection time periods and process.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Objection time periods and process. 219.56 Section 219.56 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE PLANNING Pre-Decisional Administrative Review Process § 219.56 Objection time periods and process. (a) Time to file an objection. For a...

  17. 36 CFR 219.56 - Objection time periods and process.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Objection time periods and... AGRICULTURE PLANNING Pre-Decisional Administrative Review Process § 219.56 Objection time periods and process. (a) Time to file an objection. For a new plan, plan amendment, or plan revision for which...

  18. 36 CFR 219.56 - Objection time periods and process.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Objection time periods and... AGRICULTURE PLANNING Pre-Decisional Administrative Review Process § 219.56 Objection time periods and process. (a) Time to file an objection. For a new plan, plan amendment, or plan revision for which...

  19. Canadian medical education: 50 years of innovation and leadership.

    PubMed

    Dauphinee, W D

    1993-05-01

    Over the past 50 years, many Canadian medical educators have pursued ideas and visions, as individuals in the 1950s and 1960s and later in partnership with various national bodies. Relations between universities and national medical organizations have been productive in dealing with issues of postgraduate education and clinical assessment, in particular. From 1970 to 1990, strong education offices and formally trained educators led to many successes in the areas of research in cognition, continuing medical education and clinical assessment. Canadian medical education has now achieved international recognition for its work in all aspects of the continuum of the physician's education through vision, initiative and cooperation. PMID:8477386

  20. Flavor Physics and Nagoya --- The Past 50 Years

    NASA Astrophysics Data System (ADS)

    Sanda, A. I.

    In this talk, I briefly review how Nagoya physics has contributed tothe development of flavor physics over the past 50 years. It began with the introduction of Sakata model back in 1956, and recently it contributed to the discovery of CP violation in 2000. Along the way Kobayashi and Maskawa completed the standard model by introducing the KM ansatz for CP violation. We shall also describe two discoveries by Nagoya emulsion group made before 1990: (1) the first evidence for the charm quark; (2) discovery of the D(0) and D(+) mesons.

  1. Toward the second 50 years of Water Resources Research

    NASA Astrophysics Data System (ADS)

    Rajaram, H.

    2014-12-01

    Since the first issue in 1965, 49 volumes and 464 issues of Water Resources Research (WRR) have been published, including more than 13,800 contributions that received more than 380,000 citations. WRR has always maintained a forward-looking vision, providing an interdisciplinary platform to nurture the initiation and development of numerous sub-disciplines and research themes in hydrology, water resources, and earth sciences and over the last 50 years. This vision, supported in no small measure by a dedicated community of researchers who submitted their best research to WRR, have helped the journal maintain its international leadership in this field. As we enter the second 50 years of WRR, new trends in scientific publishing, open access publication and web-based discussion forums, pose challenges (and opportunities) for sustaining WRR's leadership role. In this presentation, we will present the vision of the present editorial board for the future of WRR, and discuss several steps we are undertaking to adapt the journal to modern trends in communicating scientific research. This includes the introduction of new article types, such as the forthcoming "Debates on Water Resources", targeted special sections, and efforts to improve the timeliness of the review process. We humbly stand on the shoulders of the thirty-four dedicated previous editors of WRR, and remain open to receiving suggestions from the AGU hydrologic community.

  2. [50 years of hepatology - from therapeutic nihilism to targeted therapies].

    PubMed

    Manns, Michael P

    2013-04-01

    Over the past 50 years significant progress has been made in the whole field of hepatology. Part of this is translation of basic research (biochemistry, immunology, virology, molecular biology and others) into clinical hepatology. This enabled us to understand more about the pathogenesis of liver diseases and led to the discovery of the five major hepatotropic viruses, the identification of hepatocellular autoantigens, and to the development of specific therapies for chronic hepatitis B, C and D. In addition, the molecular basis of most genetic liver diseases has been identified. Significant progress was made in the development of medical therapies for various liver diseases with different underlying etiologies. Surgery significantly contributed to the progress in the management of liver diseases; examples are laparoscopic cholecystectomy and the development of liver transplantation. A multimodal therapeutic algorithm has been established for the therapy of hepatocelluar carcinoma (HCC); with Sorafenib "targeted therapy" has entered the area of HCC. The progress made over the last 50 years not only led to an aetiological differentiation of acute and chronic liver diseases but also to specific therapies based on the identification and understanding of the underlying etiology. PMID:23585265

  3. Mining approximate periodic pattern in hydrological time series

    NASA Astrophysics Data System (ADS)

    Zhu, Y. L.; Li, S. J.; Bao, N. N.; Wan, D. S.

    2012-04-01

    There is a lot of information about the hidden laws of nature evolution and the influences of human beings activities on the earth surface in long sequence of hydrological time series. Data mining technology can help find those hidden laws, such as flood frequency and abrupt change, which is useful for the decision support of hydrological prediction and flood control scheduling. The periodic nature of hydrological time series is important for trend forecasting of drought and flood and hydraulic engineering planning. In Hydrology, the full period analysis of hydrological time series has attracted a lot of attention, such as the discrete periodogram, simple partial wave method, Fourier analysis method, and maximum entropy spectral analysis method and wavelet analysis. In fact, the hydrological process is influenced both by deterministic factors and stochastic ones. For example, the tidal level is also affected by moon circling the Earth, in addition to the Earth revolution and its rotation. Hence, there is some kind of approximate period hidden in the hydrological time series, sometimes which is also called the cryptic period. Recently, partial period mining originated from the data mining domain can be a remedy for the traditional period analysis methods in hydrology, which has a loose request of the data integrity and continuity. They can find some partial period in the time series. This paper is focused on the partial period mining in the hydrological time series. Based on asynchronous periodic pattern and partial period mining with suffix tree, this paper proposes to mine multi-event asynchronous periodic pattern based on modified suffix tree representation and traversal, and invent a dynamic candidate period intervals adjusting method, which can avoids period omissions or waste of time and space. The experimental results on synthetic data and real water level data of the Yangtze River at Nanjing station indicate that this algorithm can discover hydrological

  4. 36 CFR 218.26 - Objection time periods.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROJECT-LEVEL PREDECISIONAL ADMINISTRATIVE REVIEW PROCESS Provisions Specific to Project-Level Proposals Not Authorized Under Healthy Forests Restoration Act § 218.26 Objection time periods. (a) Time to...

  5. 36 CFR 218.32 - Objection time periods.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROJECT-LEVEL PREDECISIONAL ADMINISTRATIVE REVIEW PROCESS Provisions Specific to Proposed Projects Authorized Under the Healthy Forests Restoration Act § 218.32 Objection time periods. (a) Time to file...

  6. 36 CFR 218.32 - Objection time periods.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROJECT-LEVEL PREDECISIONAL ADMINISTRATIVE REVIEW PROCESS Provisions Specific to Proposed Projects Authorized Under the Healthy Forests Restoration Act § 218.32 Objection time periods. (a) Time to file...

  7. 36 CFR 218.26 - Objection time periods.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROJECT-LEVEL PREDECISIONAL ADMINISTRATIVE REVIEW PROCESS Provisions Specific to Project-Level Proposals Not Authorized Under Healthy Forests Restoration Act § 218.26 Objection time periods. (a) Time to...

  8. Watershed-scale Evapotranspiration Changed Little over 50 years of Agricultural Land Abandonment in Southern Michigan

    NASA Astrophysics Data System (ADS)

    Hamilton, S. K.; Hussain, M. Z.; Lowrie, C. J.

    2015-12-01

    The difference between precipitation and stream discharge over annual periods provides an indication of the total water loss to evaporation and evapotranspiration. The response of evaporative water loss to land cover change affects groundwater recharge, stream flow, and lake levels. This study examined the watershed water balance for Augusta Creek, which drains a 95-km2 glacial landscape in southwestern Michigan covered by cropland, grassland, forest, and wetlands. The climate is humid and temperate; between 1964-2014 the water-year precipitation averaged 948 mm and ranged from 695-1386 mm with no temporal trend. Over the study period the percentage of land in agriculture has decreased to about a third of its original extent, with abandoned lands gradually transitioning from old fields to woody vegetation. Comparison of precipitation on the upland watershed to baseflow discharge (USGS data; baseflow estimation by WHAT model) across the 50-year record shows that total evaporative water loss averaged 563 + 103 mm and ranged from 385-897 mm, with no apparent trend over the record. The evaporative water loss accounts for a mean + s.d. of 59 + 6% of precipitation (range, 48-70%). Evaporative water loss was positively related to total precipitation (r2 = 0.74. These results are interpreted using a Budyko plot framework to facilitate comparison with other settings. This water balance approach to infer evaporative water loss compares well with direct measurements in the same watershed since 2009 using eddy covariance (grasslands and crops) and soil moisture monitoring by time-domain reflectometry (grasslands, crops, and forest). Thus the evaporative water loss, which is predominantly by evapotranspiration, has been remarkably similar across a period of changing land cover, leaving a relatively consistent proportion for groundwater recharge and streamflow.

  9. 50 years of screening in the Nordic countries: quantifying the effects on cervical cancer incidence

    PubMed Central

    Vaccarella, S; Franceschi, S; Engholm, G; Lönnberg, S; Khan, S; Bray, F

    2014-01-01

    Background: Nordic countries' data offer a unique possibility to evaluate the long-term benefit of cervical cancer screening in a context of increasing risk of human papillomavirus infection. Methods: Ad hoc-refined age-period-cohort models were applied to the last 50-year incidence data from Denmark, Finland, Norway and Sweden to project expected cervical cancer cases in a no-screening scenario. Results: In the absence of screening, projected incidence rates for 2006–2010 in Nordic countries would have been between 3 and 5 times higher than observed rates. Over 60 000 cases or between 41 and 49% of the expected cases of cervical cancer may have been prevented by the introduction of screening in the late 1960 s and early 1970 s. Conclusions: Our study suggests that screening programmes might have prevented a HPV-driven epidemic of cervical cancer in Nordic countries. According to extrapolations from cohort effects, cervical cancer incidence rates in the Nordic countries would have been otherwise comparable to the highest incidence rates currently detected in low-income countries. PMID:24992581

  10. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 2 2011-04-01 2011-04-01 false Time period. 158.21a Section 158.21a Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... While in Customs Custody § 158.21a Time period. An abatement or refund of duties shall be made in...

  11. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Time period. 158.21a Section 158.21a Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... While in Customs Custody § 158.21a Time period. An abatement or refund of duties shall be made in...

  12. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false How are time periods computed? 45.3 Section 45.3 Public Lands: Interior Office of the Secretary of the Interior CONDITIONS AND PRESCRIPTIONS IN FERC HYDROPOWER LICENSES General Provisions § 45.3 How are time periods computed? (a)...

  13. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false How are time periods computed? 45.3 Section 45.3 Public Lands: Interior Office of the Secretary of the Interior CONDITIONS AND PRESCRIPTIONS IN FERC HYDROPOWER LICENSES General Provisions § 45.3 How are time periods computed? (a)...

  14. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true How are time periods computed? 45.3 Section 45.3 Public Lands: Interior Office of the Secretary of the Interior CONDITIONS AND PRESCRIPTIONS IN FERC HYDROPOWER LICENSES General Provisions § 45.3 How are time periods computed? (a) General....

  15. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false How are time periods computed? 45.3 Section 45.3 Public Lands: Interior Office of the Secretary of the Interior CONDITIONS AND PRESCRIPTIONS IN FERC HYDROPOWER LICENSES General Provisions § 45.3 How are time periods computed? (a)...

  16. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false How are time periods computed? 45.3 Section 45.3 Public Lands: Interior Office of the Secretary of the Interior CONDITIONS AND PRESCRIPTIONS IN FERC HYDROPOWER LICENSES General Provisions § 45.3 How are time periods computed? (a)...

  17. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 2 2014-04-01 2014-04-01 false Time period. 158.21a Section 158.21a Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... While in Customs Custody § 158.21a Time period. An abatement or refund of duties shall be made in...

  18. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 2 2012-04-01 2012-04-01 false Time period. 158.21a Section 158.21a Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... While in Customs Custody § 158.21a Time period. An abatement or refund of duties shall be made in...

  19. The triple helix: 50 years later, the outcome

    PubMed Central

    Duca, Maria; Vekhoff, Pierre; Oussedik, Kahina; Halby, Ludovic; Arimondo, Paola B.

    2008-01-01

    Triplex-forming oligonucleotides constitute an interesting DNA sequence-specific tool that can be used to target cleaving or cross-linking agents, transcription factors or nucleases to a chosen site on the DNA. They are not only used as biotechnological tools but also to induce modifications on DNA with the aim to control gene expression, such as by site-directed mutagenesis or DNA recombination. Here, we report the state of art of the triplex-based anti-gene strategy 50 years after the discovery of such a structure, and we show the importance of the actual applications and the main challenges that we still have ahead of us. PMID:18676453

  20. 50 years of CP violation — What have we learned?

    SciTech Connect

    McKellar, Bruce H. J.

    2015-04-24

    Early after the discovery of CP violation, the explanation of how the Standard Model of particle physics could allow CP violation was quickly given, but it took many years for the original observation to be unequivocally explained on that basis. It was also proposed that this observation opened up the possibility that we could now explain the fact that the universe is made of matter. Remarkably, 50 years later we have no evidence in particle physics that there is any CP violation except that of the Kobayashi Maskawa mechanism of the standard model. Yet we fail completely to explain the baryon asymmetry of the Universe through that mechanism. After reviewing the main points in the history I describe the present experimental attempts to find CP violation beyond the standard model, and explain the theoretical attempts to explain the matter in the Universe.

  1. [Molecular bases of cellular senescence: Hayflick phenomenon 50 years later].

    PubMed

    Sosińska, Patrycja; Mikuła-Pietrasik, Justyna; Książek, Krzysztof

    2016-01-01

    Normal human somatic cells have strictly limited proliferative capacity and reach a state of senescence when it becomes exhausted. It is believed that senescence is a response to extensive and irreparable DNA injury, localized in telomeric and/or non-telomeric regions of the genome. Main cause of this damage is oxidative stress, increasing due to deteriorated function of mitochondria. Senescent cells accumulate in tissues during aging, which is causatively linked with the development of various pathologies in elderly individuals, including cancer. This paper, prepared exactly 50 years after Leonard Hayflick's discovery of the relationship between cellular senescence and organismal aging is aimed at presenting the current knowledge about molecular determinants of senescence, with particular emphasis paid to the role of oxidative stress, effectors of senescence at the level of cell cycle, markers of this phenomenon, and the effect of senescent cells on the development of certain age-related diseases. PMID:27117098

  2. Threshold dynamics of a time periodic reaction-diffusion epidemic model with latent period

    NASA Astrophysics Data System (ADS)

    Zhang, Liang; Wang, Zhi-Cheng; Zhao, Xiao-Qiang

    2015-05-01

    In this paper, we first propose a time-periodic reaction-diffusion epidemic model which incorporates simple demographic structure and the latent period of infectious disease. Then we introduce the basic reproduction number R0 for this model and prove that the sign of R0 - 1 determines the local stability of the disease-free periodic solution. By using the comparison arguments and persistence theory, we further show that the disease-free periodic solution is globally attractive if R0 < 1, while there is an endemic periodic solution and the disease is uniformly persistent if R0 > 1.

  3. Biogeochemical control of marine productivity in the Mediterranean Sea during the last 50 years

    NASA Astrophysics Data System (ADS)

    Macias, Diego; Garcia-Gorriz, Elisa; Piroddi, Chiara; Stips, Adolf

    2014-08-01

    The temporal dynamics of biogeochemical variables derived from a coupled 3-D model of the Mediterranean Sea are evaluated for the last 50 years (1960-2010) against independent data on fisheries catch per unit effort (CPUE) for the same time period. Concordant patterns are found in the time series of all of the biological variables (from the model and from fisheries statistics), with low values at the beginning of the series, a later increase, with maximum levels reached at the end of the 1990s, and a posterior stabilization. Spectral analysis of the annual biological time series reveals coincident low-frequency signals in all of them. The first, more energetic signal peaks around the year 2000, while the second, less energetic signal peaks near 1982. Almost identical low-frequency signals are found in the nutrient loads of the rivers and in the integrated nutrient levels in the surface marine ecosystem. Nitrate concentration shows a maximum level in 1998, with a later stabilization to present-day values, coincident with the first low-frequency signal found in the biological series. Phosphate shows maximum concentrations around 1982 and a posterior sharp decline, in concordance with the second low-frequency signal observed in the biological series. That result seems to indicate that the control of marine productivity (plankton to fish) in the Mediterranean is principally mediated through bottom-up processes that could be traced back to the characteristics of riverine discharges. The high sensitivity of CPUE time series to environmental conditions might be another indicator of the overexploitation of this marine ecosystem.

  4. Molecular Typing of Pathogenic Leptospira Serogroup Icterohaemorrhagiae Strains Circulating in China during the Past 50 Years

    PubMed Central

    Zhang, Cuicai; Yang, Huimian; Li, Xiuwen; Cao, Zhiqiang; Zhou, Haijian; Zeng, Linzi; Xu, Jianmin; Xu, Yinghua; Chang, Yung-Fu; Guo, Xiaokui; Zhu, Yongzhang; Jiang, Xiugao

    2015-01-01

    Background Leptospirosis is one of the most important neglected tropical infectious diseases worldwide. Icterohaemorrhagiae has been throughout recent history, and still is, the predominant serogroup of this pathogen in China. However, very little in detail is known about the serovars or genotypes of this serogroup. Methodology/Principal Findings In this study, 120 epidemic strains from five geographically diverse regions in China collected over a 50 year period (1958~2008), and 8 international reference strains characterized by 16S rRNA sequencing and MLST analysis. 115, 11 and 2 strains were identified as L. interrogans, L. borgpetersenii, and L. kirschneri, respectively. 17 different STs were identified including 69 ST1 strains, 18 ST17, 18 ST128, 9 ST143 and 2 ST209. The remaining 12 strains belonged to 12 different STs. eBURST analysis demonstrated that, among the clonal complexes isolated (CCs), CC1 accounted for 73.3% (88/120) strains representing three STs: ST1, ST128 and ST98. ST1 was the most likely ancestral strain of this CC, followed by singleton CC17 (17/120) and CC143 (11/120). Further analysis of adding 116 serogroup Icterohaemorrhagiae strains in the MLST database and studies previously described using global eBURST analysis and MST dendrogram revealed relatively similar ST clustering patterns with five main CCs and 8 singletons among these 244 strains. CC17 was found to be the most prevalent clone of pathogenic Leptospira circulating worldwide. This is the first time, to our knowledge, that ST1 and ST17 strains were distributed among 4 distinct serovars, indicating a highly complicated relationship between serovars and STs. Conclusions/Significance Our studies demonstrated a high level of genetic diversity in the serogroup Icterohaemorrhagiae strains. Distinct from ST17 or ST37 circulating elsewhere, ST1 included in CC1, has over the past 50 years or so, proven to be the most prevalent ST of pathogenic leptospires isolated in China. Moreover, the

  5. Local time dependences of oxygen ENA periodicities at Saturn

    NASA Astrophysics Data System (ADS)

    Carbary, J. F.; Mitchell, D. G.; Brandt, P. C.

    2014-08-01

    The periodicities of energetic neutral atoms (90-170 keV oxygens) at Saturn are determined by applying Lomb-Scargle periodogram analyses to energetic neutral atom (ENA) fluxes observed in eight local time sectors of the equatorial plane between 5 and 15 RS (1 RS = 60,268 km). The analyses come from four long intervals (>180 days each) of high-latitude viewing from 2007 to 2013 and represent an essentially global view of Saturn's periodicities. The periodograms display rich and complex structures in local time. Sectors near midnight generally exhibit the strongest periodicities (in terms of highest signal-to-noise ratios) and often show the dual or single periods of the Saturn kilometric radiation (SKR). Sectors near noon display single or multiple periodicities or none. Furthermore, dayside periods may be much shorter (~10.3 h) than SKR periods. Sectors near dawn or dusk display periodicities intermediate between midnight and noon or may show no periodicities whatsoever. These patterns of local time dependence do not remain constant from interval to interval.

  6. 50 years of computer simulation of the human thermoregulatory system.

    PubMed

    Hensley, Daniel W; Mark, Andrew E; Abella, Jayvee R; Netscher, George M; Wissler, Eugene H; Diller, Kenneth R

    2013-02-01

    This paper presents an updated and augmented version of the Wissler human thermoregulation model that has been developed continuously over the past 50 years. The existing Fortran code is translated into C with extensive embedded commentary. A graphical user interface (GUI) has been developed in Python to facilitate convenient user designation of input and output variables and formatting of data presentation. Use of the code with the GUI is described and demonstrated. New physiological elements were added to the model to represent the hands and feet, including the unique vascular structures adapted for heat transfer associated with glabrous skin. The heat transfer function and efficacy of glabrous skin is unique within the entire body based on the capacity for a very high rate of blood perfusion and the novel capability for dynamic regulation of blood flow. The model was applied to quantify the absolute and relative contributions of glabrous skin flow to thermoregulation for varying levels of blood perfusion. The model also was used to demonstrate how the unique features of glabrous skin blood flow may be recruited to implement thermal therapeutic procedures. We have developed proprietary methods to manipulate the control of glabrous skin blood flow in conjunction with therapeutic devices and simulated the effect of these methods with the model. PMID:23445051

  7. Conformational selection or induced fit? 50 years of debate resolved

    PubMed Central

    Edelstein, Stuart

    2011-01-01

    Exactly 50 years ago, biochemists raised the question of the mechanism of the conformational change that mediates “allosteric” interactions between regulatory sites and biologically active sites in regulatory/receptor proteins. Do the different conformations involved already exist spontaneously in the absence of the regulatory ligands (Monod-Wyman-Changeux), such that the complementary protein conformation would be selected to mediate signal transduction, or do particular ligands induce the receptor to adopt the conformation best suited to them (Koshland-Nemethy-Filmer—induced fit)? This is not just a central question for biophysics, it also has enormous importance for drug design. Recent advances in techniques have allowed detailed experimental and theoretical comparisons with the formal models of both scenarios. Also, it has been shown that mutated receptors can adopt constitutively active confirmations in the absence of ligand. There have also been demonstrations that the atomic resolution structures of the same protein are essentially the same whether ligand is bound or not. These and other advances in past decades have produced a situation where the vast majority of the data using different categories of regulatory proteins (including regulatory enzymes, ligand-gated ion channels, G protein-coupled receptors, and nuclear receptors) support the conformational selection scheme of signal transduction. PMID:21941598

  8. 50 years of space science (Jean Dominique Cassini Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Bonnet, Roger-Maurice

    2013-04-01

    The launch of Sputnik-1 triggered my fascination for space at the age of 20. The past 50 years have allowed me to study the Sun with sounding rockets and satellites, revealing the complexity of our star, contributing to the understanding of its physics, and offering surprising manifestations of its behavior and of its effects on Earth. Building instruments for space astronomy, managing teams of space scientists and engineers, led me to become the science director of the European space agency between 1983 and 2001 where I formulated and managed the Horizon 2000 program, which led Europe to occupy the front row of world space science. The Jean Dominique Cassini Medal Lecture offers me an opportunity, to describe the most spectacular achievements of this long-term plan and to outline some basic principles for reaching success, including the essential role of international cooperation with shared partnership. The Lecture also identifies key problems and controversial issues that space astronomy and exploration will face in the 21st century.

  9. 50 years of hurdles and hope in anxiolytic drug discovery

    PubMed Central

    Griebel, Guy; Holmes, Andrew

    2014-01-01

    Anxiety disorders are the most prevalent group of psychiatric diseases, and have high personal and societal costs. The search for novel pharmacological treatments for these conditions is driven by the growing medical need to improve on the effectiveness and the side effect profile of existing drugs. A huge volume of data has been generated by anxiolytic drug discovery studies, which has led to the progression of numerous new molecules into clinical trials. However, the clinical outcome of these efforts has been disappointing, as promising results with novel agents in rodent studies have very rarely translated into effectiveness in humans. Here, we analyse the major trends from preclinical studies over the past 50 years conducted in the search for new drugs beyond those that target the prototypical anxiety-associated GABA (γ-aminobutyric acid)–benzodiazepine system, which have focused most intensively on the serotonin, neuropeptide, glutamate and endocannabinoid systems. We highlight various key issues that may have hampered progress in the field, and offer recommendations for how anxiolytic drug discovery can be more effective in the future. PMID:23989795

  10. Aflatoxin: A 50-Year Odyssey of Mechanistic and Translational Toxicology

    PubMed Central

    Kensler, Thomas W.; Roebuck, Bill D.; Wogan, Gerald N.; Groopman, John D.

    2011-01-01

    Since their discovery 50 years ago, the aflatoxins have become recognized as ubiquitous contaminants of the human food supply throughout the economically developing world. The adverse toxicological consequences of these compounds in populations are quite varied because of a wide range of exposures leading to acute effects, including rapid death, and chronic outcomes such as hepatocellular carcinoma. Furthermore, emerging studies describe a variety of general adverse health effects associated with aflatoxin, such as impaired growth in children. Aflatoxin exposures have also been demonstrated to multiplicatively increase the risk of liver cancer in people chronically infected with hepatitis B virus (HBV) illustrating the deleterious impact that even low toxin levels in the diet can pose for human health. The public health impact of aflatoxin exposure is pervasive. Aflatoxin biomarkers of internal and biologically effective doses have been integral to the establishment of the etiologic role of this toxin in human disease through better estimates of exposure, expanded knowledge of the mechanisms of disease pathogenesis, and as tools for implementing and evaluating preventive interventions. PMID:20881231

  11. Backwards and Forwards: 50 years of the Education Group

    NASA Astrophysics Data System (ADS)

    2000-01-01

    by representatives from a number of equally prestigious universities. In one, the large physics lecture rooms were taken over by philosophy students, as smaller physics groups traipsed across to distant biology rooms. It was this kind of situation, plus the reduction in the level of technician support, that made demonstrations harder to organize. In the lively discussion that followed Professor Brown's talk there was strong support for his proposal that universities - with the help of the IoP and the Royal Society, say - should set up a national `demonstration bank' that could be tapped to provide portable, well-tried, well-resourced and well-rehearsed demonstrations. Envy was expressed for the bank of experiments and demonstrations available at school level, especially as presented by the Advancing Physics CD-ROM. Universities could also learn from the course designs exemplified by Advancing Physics and the York Salters Horners projects: a set of self-contained, coherent topics with clear end-points and built-in mathematics, with key concepts well-illustrated by relevant experiments. The final session was given by Ken Dobson, who had the onerous but luckily uncheckable task of talking about Physics education: the next 50 years! (organizer's emphasis). In less than 15 minutes he expressed his complete incompetence at carrying out such a task, but in spite of that went on to compare the current state of progress (leading to an unfortunate state of dystopia) with what he thought should happen (leading to a much happier state of utopia). The key differences were the current over-centralization, mechanistic and top-down direction of education based on a system-centred command-psychology, as compared with an organic, self-directed, learner-centred education. He called the first dystopian model the Rucsac Model : everything you needed for life had to be packed by the time you left school, and should serve you all your days. By contrast, he called the utopian future a

  12. Particle energization through time-periodic helical magnetic fields.

    PubMed

    Mitra, Dhrubaditya; Brandenburg, Axel; Dasgupta, Brahmananda; Niklasson, Eyvind; Ram, Abhay

    2014-04-01

    We solve for the motion of charged particles in a helical time-periodic ABC (Arnold-Beltrami-Childress) magnetic field. The magnetic field lines of a stationary ABC field with coefficients A=B=C=1 are chaotic, and we show that the motion of a charged particle in such a field is also chaotic at late times with positive Lyapunov exponent. We further show that in time-periodic ABC fields, the kinetic energy of a charged particle can increase indefinitely with time. At late times the mean kinetic energy grows as a power law in time with an exponent that approaches unity. For an initial distribution of particles, whose kinetic energy is uniformly distributed within some interval, the probability density function of kinetic energy is, at late times, close to a Gaussian but with steeper tails. PMID:24827325

  13. Instruction and Curriculum in Veterinary Medical Education: A 50-Year Perspective.

    PubMed

    Fletcher, Oscar J; Hooper, Billy E; Schoenfeld-Tacher, Regina

    2015-01-01

    Our knowledge of veterinary medicine has expanded greatly over the past 50 years. To keep pace with these changes and produce competent professionals ready to meet evolving societal needs, instruction within veterinary medical curricula has undergone a parallel evolution. The curriculum of 1966 has given way, shifting away from lecture-laboratory model with few visual aids to a program of active learning, significant increases in case- or problem-based activities, and applications of technology, including computers, that were unimaginable 50 years ago. Curricula in veterinary colleges no longer keep all students in lockstep or limit clinical experiences to the fourth year, and instead have moved towards core electives with clinical activities provided from year 1. Provided here are examples of change within veterinary medical education that, in the view of the authors, had positive impacts on the evolution of instruction and curriculum. These improvements in both how and what we teach are now being made at a more rapid pace than at any other time in history and are based on the work of many faculty and administrators over the past 50 years. PMID:26673214

  14. Geochemical Diversity of the Mantle: 50 Years of Acronyms

    NASA Astrophysics Data System (ADS)

    Hart, S. R.

    2014-12-01

    50 years ago, Gast, Tilton and Hedge demonstrated that the oceanic mantle is isotopically heterogeneous. 28 years ago, Zindler and Hart formalized the concept of geochemical mantle components, with an attendant, to some, odious, acronym soup. Work on a marriage of mantle geochemistry and dynamics continues unabated. We know unequivocally that the mantle is chemically heterogeneous; we do not know the scale lengths of these heterogeneities. We know unequivocally that these heterogeneities have persisted for eons (Gy); we do not know where they were formed or where they are stored. Through the kind auspices of the Plume Model, we plausibly have access to the whole mantle. The most accessible and well understood mantle reservoir is the upper depleted MORB mantle (DMM). Classically, this mantle was depleted by extraction of oceanic and continental crust from a "chondritic" bulk silicate Earth. In this post-Boyet and Carlson world, the complementary enriched reservoir may instead be hidden in the deepest mantle. In this case, DMM will become an endangered acronym. Hofmann and White (1982) argued that radiogenic Pb mantle (HIMU) is re-cycled ocean crust, and this is a comfortably viable model. It does require some ad hoc chemical manipulations during subduction. Given 2 Gy of aggregate mantle strains, the mafic component in HIMU may be of small length scale (< 50 m), possibly subsumed into the dominant peridotitic lithology. This mantle species is globally widespread. Enriched mantles (EM1 and EM2) almost certainly reflect recycling of enriched continental material. This was splendidly verified by Jackson et al (2007), with 87Sr/86Sr in Samoan EM2 lavas up to 0.721. The lithology and length scale of EM1 and EM2 is unconstrained. EM1 is globally present; EM2 is confined to the SW Pacific hotspots. FOZO is a work in progress; many would like to see it become extinct! The trace element signatures of HIMU and FOZO mantles have been constrained using melting models; in both

  15. Identifying multiple periodicities in sparse photon event time series

    NASA Astrophysics Data System (ADS)

    Koen, Chris

    2016-07-01

    The data considered are event times (e.g. photon arrival times, or the occurrence of sharp pulses). The source is multiperiodic, or the data could be multiperiodic because several unresolved sources contribute to the time series. Most events may be unobserved, either because the source is intermittent, or because some events are below the detection limit. The data may also be contaminated by spurious pulses. The problem considered is the determination of the periods in the data. A two-step procedure is proposed: in the first, a likely period is identified; in the second, events associated with this periodicity are removed from the time series. The steps are repeated until the remaining events do not exhibit any periodicity. A number of period-finding methods from the literature are reviewed, and a new maximum likelihood statistic is also introduced. It is shown that the latter is competitive compared to other techniques. The proposed methodology is tested on simulated data. Observations of two rotating radio transients are discussed, but contrary to claims in the literature, no evidence for multiperiodicity could be found.

  16. Identifying Multiple Periodicities in Sparse Photon Event Time Series

    NASA Astrophysics Data System (ADS)

    Koen, Chris

    2016-04-01

    The data considered are event times (e.g. photon arrival times, or the occurrence of sharp pulses). The source is multiperiodic, or the data could be multiperiodic because several unresolved sources contribute to the time series. Most events may be unobserved, either because the source is intermittent, or because some events are below the detection limit. The data may also be contaminated by spurious pulses. The problem considered is the determination of the periods in the data. A two-step procedure is proposed: in the first, a likely period is identified; in the second, events associated with this periodicity are removed from the time series. The steps are repeated until the remaining events do not exhibit any periodicity. A number of period-finding methods from the literature are reviewed, and a new maximum likelihood statistic is also introduced. It is shown that the latter is competitive compared to other techniques. The proposed methodology is tested on simulated data. Observations of two rotating radio transients are discussed, but contrary to claims in the literature, no evidence for multiperiodicity could be found.

  17. Optimal health insurance for multiple goods and time periods.

    PubMed

    Ellis, Randall P; Jiang, Shenyi; Manning, Willard G

    2015-05-01

    We examine the efficiency-based arguments for second-best optimal health insurance with multiple treatment goods and multiple time periods. Correlated shocks across health care goods and over time interact with complementarity and substitutability to affect optimal cost sharing. Health care goods that are substitutes or have positively correlated demand shocks should have lower optimal patient cost sharing. Positive serial correlations of demand shocks and uncompensated losses that are positively correlated with covered health services also reduce optimal cost sharing. Our results rationalize covering pharmaceuticals and outpatient spending more fully than is implied by static, one good, or one period models. PMID:25727031

  18. 26 CFR 301.7701(b)-4 - Residency time periods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... statement (described in paragraph (c)(3)(v)(C) of this section) to the individual's income tax return (Form... tax return for the election year, the alien individual may request an extension of time for filing the return until a reasonable period after he or she has satisfied such test, provided that the...

  19. 50 CFR 221.3 - How are time periods computed?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false How are time periods computed? 221.3 Section 221.3 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS PRESCRIPTIONS IN FERC HYDROPOWER LICENSES...

  20. 50 CFR 221.3 - How are time periods computed?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false How are time periods computed? 221.3 Section 221.3 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS PRESCRIPTIONS IN FERC HYDROPOWER LICENSES...

  1. 50 CFR 221.3 - How are time periods computed?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 10 2013-10-01 2013-10-01 false How are time periods computed? 221.3 Section 221.3 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS PRESCRIPTIONS IN FERC HYDROPOWER LICENSES...

  2. 50 CFR 221.3 - How are time periods computed?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 10 2014-10-01 2014-10-01 false How are time periods computed? 221.3 Section 221.3 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS PRESCRIPTIONS IN FERC HYDROPOWER LICENSES...

  3. 50 CFR 221.3 - How are time periods computed?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false How are time periods computed? 221.3 Section 221.3 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS PRESCRIPTIONS IN FERC HYDROPOWER LICENSES...

  4. 36 CFR 218.10 - Objection time periods and process.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Objection time periods and process. 218.10 Section 218.10 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE PREDECISIONAL ADMINISTRATIVE REVIEW PROCESSES Predecisional Administrative Review Process for Hazardous Fuel Reduction Projects Authorized...

  5. Physical Activity in High School during "Free-Time" Periods

    ERIC Educational Resources Information Center

    Silva, Pedro; Sousa, Michael; Sá, Carla; Ribeiro, José; Mota, Jorge

    2015-01-01

    The purpose of this study was to examine youth physical activity (PA) in free-time periods during high school days and their contribution to total PA. Differences in terms of sex, age, body mass index and school level were assessed in a sample of Portuguese adolescents. Participants totalled 213 (135 girls), aged 14.6 ± 1.7, from two different…

  6. Positive particle frequencies in some time-periodic universes

    NASA Astrophysics Data System (ADS)

    Droz-Vincent, Philippe

    1996-03-01

    We consider the Klein-Gordon equation in FRW-like universes which are periodic in a suitable scale of time. In a remarkable sector of solutions, the Floquet theory of differential equations allows for generalizing the notion of particle frequency. In this sense, the sesquilinear form associated with Gordon's current is positive definite when restricted to the sub-sector of positive frequencies.

  7. 36 CFR 218.10 - Objection time periods and process.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Objection time periods and process. 218.10 Section 218.10 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF... Hazardous Fuel Reduction Projects Authorized by the Healthy Forests Restoration Act of 2003 §...

  8. False periodicities in quasar time-domain surveys

    NASA Astrophysics Data System (ADS)

    Vaughan, S.; Uttley, P.; Markowitz, A. G.; Huppenkothen, D.; Middleton, M. J.; Alston, W. N.; Scargle, J. D.; Farr, W. M.

    2016-09-01

    There have recently been several reports of apparently periodic variations in the light curves of quasars, e.g. PG 1302-102 by Graham et al. Any quasar showing periodic oscillations in brightness would be a strong candidate to be a close binary supermassive black hole and, in turn, a candidate for gravitational wave studies. However, normal quasars - powered by accretion on to a single, supermassive black hole - usually show stochastic variability over a wide range of time-scales. It is therefore important to carefully assess the methods for identifying periodic candidates from among a population dominated by stochastic variability. Using a Bayesian analysis of the light curve of PG 1302-102, we find that a simple stochastic process is preferred over a sinusoidal variation. We then discuss some of the problems one encounters when searching for rare, strictly periodic signals among a large number of irregularly sampled, stochastic time series, and use simulations of quasar light curves to illustrate these points. From a few thousand simulations of steep spectrum (`red noise') stochastic processes, we find many simulations that display few-cycle periodicity like that seen in PG 1302-102. We emphasize the importance of calibrating the false positive rate when the number of targets in a search is very large.

  9. Time-periodic solutions of the Benjamin-Ono equation

    SciTech Connect

    Ambrose , D.M.; Wilkening, Jon

    2008-04-01

    We present a spectrally accurate numerical method for finding non-trivial time-periodic solutions of non-linear partial differential equations. The method is based on minimizing a functional (of the initial condition and the period) that is positive unless the solution is periodic, in which case it is zero. We solve an adjoint PDE to compute the gradient of this functional with respect to the initial condition. We include additional terms in the functional to specify the free parameters, which, in the case of the Benjamin-Ono equation, are the mean, a spatial phase, a temporal phase and the real part of one of the Fourier modes at t = 0. We use our method to study global paths of non-trivial time-periodic solutions connecting stationary and traveling waves of the Benjamin-Ono equation. As a starting guess for each path, we compute periodic solutions of the linearized problem by solving an infinite dimensional eigenvalue problem in closed form. We then use our numerical method to continue these solutions beyond the realm of linear theory until another traveling wave is reached (or until the solution blows up). By experimentation with data fitting, we identify the analytical form of the solutions on the path connecting the one-hump stationary solution to the two-hump traveling wave. We then derive exact formulas for these solutions by explicitly solving the system of ODE's governing the evolution of solitons using the ansatz suggested by the numerical simulations.

  10. [Historical sketch of modern pharmaceutical science and technology (Part 4). Post World War II 50 years].

    PubMed

    Yamakawa, K

    1995-01-01

    A short history of the pharmaceutical science and technology, postwar 50 years is divided into nine sections for the purpose of discussion. 1. Japan's postwar rehabilitation, Japanese pharmaceutical industries and newly developed pharmaceutical sciences and technologies. In 1945, the Japanese pharmaceutical industry was reconstructed. Production of penicillin was carried out with the strong support of the U.S. Occupation Forces. New sciences in pharmacy (biochemistry, biopharmacy, pharmacology, microbiology, physical chemistry, etc.) were introduced in this period. 2. Introduction age of foreign new drugs and technology (1951 to 1960s). Japan gained independence in 1951. Japanese pharmaceutical companies imported many new drugs and new pharmaceutical technologies from the U.S.A. and European countries in this period. Then, these companies were reconstruction rapidly. However, consequently Japanese pharmaceutical companies were formed as an imitation industry. 3. Rapid economic growth period for pharmaceutical companies (1956 to 1970s). In this period, many Japanese pharmaceutical companies grew rapidly at an annual rate of 15-20% over a period of 15 years, especially with regard to the production of active vitamin B1 analog drugs and some OTC (public health drugs). Some major companies made large profits, which were used to construct research facilities. 4. Problems for the harmful effects of medicines and its ethical responsibility. In the 1970s, many public toxic and harmful effects of medicines were caused, especially SMON's disease. In this time, many pharmaceutical companies changed to its security got development of ethical drugs. 5. Self development of new drugs and administration of pharmaceutical rules (1970s). During the 1970s, many pharmaceutical laws (GLP, GCP, GMP, GPMSP etc.) were enacted by the Ministry of Health and Welfare. In 1976, the Japanese Pharmaceutical Affairs Law was revised, which set forth standards regarding the efficacy and safety of

  11. Health and Safety Law over the Last 50 Years

    ERIC Educational Resources Information Center

    Whitcher, Ralph

    2013-01-01

    From a time when laws on health and safety applied only to some industries and much was unregulated, we have moved to a time when health and safety laws seem, if you believe some reports in the news, to pervade every aspect of working life with silly restrictions. This article looks at the development of the legislation from the 1960s and suggests…

  12. Periodicity detection method for small-sample time series datasets.

    PubMed

    Tominaga, Daisuke

    2010-01-01

    Time series of gene expression often exhibit periodic behavior under the influence of multiple signal pathways, and are represented by a model that incorporates multiple harmonics and noise. Most of these data, which are observed using DNA microarrays, consist of few sampling points in time, but most periodicity detection methods require a relatively large number of sampling points. We have previously developed a detection algorithm based on the discrete Fourier transform and Akaike's information criterion. Here we demonstrate the performance of the algorithm for small-sample time series data through a comparison with conventional and newly proposed periodicity detection methods based on a statistical analysis of the power of harmonics.We show that this method has higher sensitivity for data consisting of multiple harmonics, and is more robust against noise than other methods. Although "combinatorial explosion" occurs for large datasets, the computational time is not a problem for small-sample datasets. The MATLAB/GNU Octave script of the algorithm is available on the author's web site: http://www.cbrc.jp/%7Etominaga/piccolo/. PMID:21151841

  13. Finding unstable periodic orbits from chaotic time series

    NASA Astrophysics Data System (ADS)

    Buhl, Michael

    Contained within a chaotic attractor is an infinite number of unstable periodic orbits (UPOs). Although these orbits have zero measure, they form a skeleton of the dynamics. However, they are difficult to find from an observed time series. In this thesis I present several methods to find UPOs from measured time series. In Chapter 2 I look at data measured from the stomatogastric system of the California spiny lobster as an example to find unstable periodic orbits. With this time series I use two methods. The first creates a local linear model of the dynamics and finds the periodic orbits of the model, and the second applies a linear transform to the model such that unstable orbits are stable. In addition, in this chapter I describe methods of filtering and embedding the chaotic time series. In Chapter 3 I look at a more complicated model system where the dynamics are described by delay differential equations. Now the future state of the system depends on both the current state and the state a time tau earlier. This makes the phase space of the system infinite dimensional. I present a method for modeling systems such as this and finding UPOs in the infinite dimensional phase space. In Chapters 4 and 5 I describe a new method to find UPOs using symbolic dynamics. This has many advantages over the methods described in Chapter 2; more orbits can be found using a smaller time series---even in the presence of noise. First in Chapter 4 I describe how the phase space can be partitioned so that we can use symbolic dynamics. Then in Chapter 5 I describe how the UPOs can be found from the symbolic time series. Here, I model the symbolic dynamics with a Markov chain, represented by a graph, and then the symbolic UPOs are found from the graph. These symbolic cycles can then be localized back in phase space.

  14. Periodic, Quasi-periodic and Chaotic Dynamics in Simple Gene Elements with Time Delays

    PubMed Central

    Suzuki, Yoko; Lu, Mingyang; Ben-Jacob, Eshel; Onuchic, José N.

    2016-01-01

    Regulatory gene circuit motifs play crucial roles in performing and maintaining vital cellular functions. Frequently, theoretical studies of gene circuits focus on steady-state behaviors and do not include time delays. In this study, the inclusion of time delays is shown to entirely change the time-dependent dynamics for even the simplest possible circuits with one and two gene elements with self and cross regulations. These elements can give rise to rich behaviors including periodic, quasi-periodic, weak chaotic, strong chaotic and intermittent dynamics. We introduce a special power-spectrum-based method to characterize and discriminate these dynamical modes quantitatively. Our simulation results suggest that, while a single negative feedback loop of either one- or two-gene element can only have periodic dynamics, the elements with two positive/negative feedback loops are the minimalist elements to have chaotic dynamics. These elements typically have one negative feedback loop that generates oscillations, and another unit that allows frequent switches among multiple steady states or between oscillatory and non-oscillatory dynamics. Possible dynamical features of several simple one- and two-gene elements are presented in details. Discussion is presented for possible roles of the chaotic behavior in the robustness of cellular functions and diseases, for example, in the context of cancer. PMID:26876008

  15. Total hip arthroplasty in patients 50 years or less: do we improve activity profiles?

    PubMed

    Kuhn, Margaret; Harris-Hayes, Marcie; Steger-May, Karen; Pashos, Gail; Clohisy, John C

    2013-05-01

    The primary objective of this study was to use step activity monitoring to quantify activity changes after total hip arthroplasty in patients 50 years or less. Secondly, we investigated whether step activity measurements correlated with the Harris hip and UCLA scores. We prospectively analyzed 37 patients (age ≤ 50) treated with primary THA. Patient activity was recorded with a step activity monitor. Harris hip and UCLA scores were analyzed. Total daily stride counts increased by an average of 30.0%. Increases were noted in the percent of daily time spent at high, moderate and low activity. Increases in daily time spent at high activity moderately correlated with the UCLA activity score but did not correlate with the HHS. Both the UCLA score and the HHS did not correlate with mean daily strides. Following THA, patients ≤ 50 years of age increase their activity by taking more daily strides and improve their activity profile by spending more time at higher activity. Improvements in step activity moderately correlate with improvements in UCLA scores. PMID:23499406

  16. Time periodic perturbations and transport signatures in Floquet topological insulators

    NASA Astrophysics Data System (ADS)

    Farrell, Aaron; Pereg-Barnea, T.

    A Floquet topological insulator represents an out-of-equilibrium topological state. The topology of these systems emerges only when a time periodic perturbation is carefully applied. In time-periodic systems one can define quasi-energy states, which replace equilibrium stationary states (i.e. energy eigenstates). For appropriate time periodic potential strengths, a Floquet topological insulator exhibits edge localized quasi-energy states which lie in a gap of its quasi-energy spectrum. These edge states are a non-equilibrium analogue of the topologically protected edge-states in equilibrium topological insulators. In an equilibrium system such edge states lead to robust ``signature'' transport properties, e.g. a two-terminal conductivity of 2e2 / h . This talk will explore how these transport signatures translate to Floquet topological insulators. We will do this by developing and generalizing intuition borrowed from the field of photon-assited tunneling. We show that ultimately the signature transport properties of an equilibrium topological insulator do not directly hold in the out-of-equilibrium setting. This fact notwithstanding, we will provide an indirect way of retaining these transport signatures by using a so-called Floquet sum rule.

  17. Short time transient periodicities from Cyg X-1

    NASA Technical Reports Server (NTRS)

    Auriemma, G.; Cardini, D.; Costa, E.; Giovannelli, F.; Ranieri, M.

    1976-01-01

    The temporal behavior of three new events of modulated optical emission from Cyg X1, detected in July 1975, is presented. Short time periodicities in the optical band are investigated. Single photon pulses from the photomultiplier are recorded on magnetic tape together with a very accurate 1 kHz reference frequency. During playback of the tape, the reference signal gives a 1 ms timing to a scaler interfaced with a small processor and the number of photon per millisecond is recorded on a digital tape.

  18. Krylov-subspace acceleration of time periodic waveform relaxation

    SciTech Connect

    Lumsdaine, A.

    1994-12-31

    In this paper the author uses Krylov-subspace techniques to accelerate the convergence of waveform relaxation applied to solving systems of first order time periodic ordinary differential equations. He considers the problem in the frequency domain and presents frequency dependent waveform GMRES (FDWGMRES), a member of a new class of frequency dependent Krylov-subspace techniques. FDWGMRES exhibits many desirable properties, including finite termination independent of the number of timesteps and, for certain problems, a convergence rate which is bounded from above by the convergence rate of GMRES applied to the static matrix problem corresponding to the linear time-invariant ODE.

  19. 50 Years of C. Wright Mills and "The Sociological Imagination"

    ERIC Educational Resources Information Center

    Scanlan, Stephen J.; Grauerholz, Liz

    2009-01-01

    The core ideas and lessons of C. Wright Mills are most likely among the first perspectives to which students are exposed in sociology and are a foundation to the discipline. Although perhaps difficult to recall all of the specific details of the encounter, many of these students are likely to remember the first time that they were introduced to C.…

  20. The Original "Brown" Town after 50 Years: Desegregated, Not Integrated

    ERIC Educational Resources Information Center

    Cook, Glenn

    2004-01-01

    The story of Summerton and its schools is a footnote to history. On the surface, daily life in this small South Carolina town today is a far cry from a half century ago. At the same time, little seems to have changed--and many residents seem to prefer it that way. And with good reason, for the townspeople, especially whites, still cast a wary eye…

  1. Polio and Nobel prizes: looking back 50 years.

    PubMed

    Norrby, Erling; Prusiner, Stanley B

    2007-05-01

    In 1954, John Enders, Thomas Weller, and Frederick Robbins were awarded the Nobel Prize in Physiology or Medicine "for their discovery of the ability of poliomyelitis viruses to grow in cultures of various types of tissue."5370 This discovery provided for the first time opportunities to produce both inactivated and live polio vaccines. By searching previously sealed Nobel Committee archives, we were able to review the deliberations that led to the award. It appears that Sven Gard, who was Professor of Virus Research at the Karolinska Institute and an adjunct member of the Nobel Committee at the time, played a major role in the events leading to the awarding of the Prize. It appears that Gard persuaded the College of Teachers at the Institute to decide not to follow the recommendation by their Nobel Committee to give the Prize to Vincent du Vigneaud. Another peculiar feature of the 1954 Prize is that Weller and Robbins were included based on only two nominations submitted for the first time that year. In his speech at the Nobel Prize ceremony, Gard mentioned the importance of the discovery for the future production of vaccines, but emphasized the implications of this work for growing many different, medically important viruses. We can only speculate on why later nominations highlighting the contributions of scientists such as Jonas Salk, Hilary Koprowski, and Albert Sabin in the development of poliovirus vaccines have not been recognized by a Nobel Prize. PMID:17469121

  2. Scheduling real-time, periodic jobs using imprecise results

    NASA Technical Reports Server (NTRS)

    Liu, Jane W. S.; Lin, Kwei-Jay; Natarajan, Swaminathan

    1987-01-01

    A process is called a monotone process if the accuracy of its intermediate results is non-decreasing as more time is spent to obtain the result. The result produced by a monotone process upon its normal termination is the desired result; the error in this result is zero. External events such as timeouts or crashes may cause the process to terminate prematurely. If the intermediate result produced by the process upon its premature termination is saved and made available, the application may still find the result unusable and, hence, acceptable; such a result is said to be an imprecise one. The error in an imprecise result is nonzero. The problem of scheduling periodic jobs to meet deadlines on a system that provides the necessary programming language primitives and run-time support for processes to return imprecise results is discussed. This problem differs from the traditional scheduling problems since the scheduler may choose to terminate a task before it is completed, causing it to produce an acceptable but imprecise result. Consequently, the amounts of processor time assigned to tasks in a valid schedule can be less than the amounts of time required to complete the tasks. A meaningful formulation of this problem taking into account the quality of the overall result is discussed. Three algorithms for scheduling jobs for which the effects of errors in results produced in different periods are not cumulative are described, and their relative merits are evaluated.

  3. Patellar tendon or hamstring graft anterior cruciate ligament reconstructions in patients aged above 50 years

    PubMed Central

    Bali, Tarun; Nagraj, Raghu; Kumar, Malhar N; Chandy, Thomas

    2015-01-01

    Background: The treatment of anterior cruciate ligament (ACL) injury consists of arthroscopic ACL reconstruction with patellar tendon or hamstring graft. Satisfactory results have been reported so far in the younger age group. Dilemma arises regarding the suitability of ACL reconstruction in patients aged 50 years and above. This retrospective analyses the outcome of ACL reconstruction in patients aged 50 years and above. Materials and Methods: 55 patients aged 50 years and above presented to our institution with symptomatic ACL tear and were managed with arthroscopic reconstruction with patellar tendon/hamstring graft. 22 patients underwent ACL reconstruction with bone- patellar tendon-bone graft and the remaining 33 with a hamstring graft. Evaluation of functional outcome was performed using International Knee Documentation Committee (IKDC) and Lysholm scoring in the preoperative period, at the end of 1 year and at the final followup. Radiographic evaluation was performed using the Kellgren–Lawrence grading system. Results: The mean preoperative IKDC score was 39.7 ± 3.3. At the end of 1-year following the operation, the mean IKDC score was 73.6 ± 4.9 and at the final followup was 67.8 ± 7.7. The mean preoperative Lysholm score was 40.4 ± 10.3. At the end of 1-year following the intervention, the mean Lysholm score was 89.7 ± 2.1 and at final followup was 85.3 ± 2.5. Overall, 14 out of 42 patients who underwent radiographic assessment showed progression of osteoarthritis changes at the final followup after the intervention. Conclusion: In our study, there was a statistically significant improvement in the IKDC and Lysholm scores following the intervention. There was a slight deterioration in the scores at the final followup but the overall rate of satisfaction was still high and most of the patients were able to do their routine chores and light exercises suitable for their age group. Around one-third of patients show progression of radiographic changes

  4. Technology - The path to the next 50 years

    NASA Technical Reports Server (NTRS)

    Williams, D. P.; Sadin, S. R.

    1981-01-01

    The paper stresses the importance of committing time and resources to space technology based on the premise that an accurate appraisal of the impact of technology and other influences on the present state of aviation will facilitate the planning of space technology. The paper presents the technological advances in aviation since 1903 by dividing the era of aviation into four distinct segments and, by analogy, distinct phases are also seen in the evolution of space flight. One factor seen as limiting advances in space is cost. Processes in space must now be shown to be affordable; a demonstration of technological feasibility is no longer sufficient. For this reason, technology must focus on ensuring the affordability and utility of space processes. A commitment to making space affordable will yield the tools necessary to embark on future space ventures.

  5. The Swedish monitoring of surface waters: 50 years of adaptive monitoring.

    PubMed

    Fölster, Jens; Johnson, Richard K; Futter, Martyn N; Wilander, Anders

    2014-01-01

    For more than 50 years, scientific insights from surface water monitoring have supported Swedish evidence-based environmental management. Efforts to understand and control eutrophication in the 1960s led to construction of wastewater treatment plants with phosphorus retention, while acid rain research in the 1970s contributed to international legislation curbing emissions. By the 1990s, long-time series were being used to infer climate effects on surface water chemistry and biology. Monitoring data play a key role in implementing the EU Water Framework Directive and other legislation and have been used to show beneficial effects of agricultural management on Baltic Sea eutrophication. The Swedish experience demonstrates that well-designed and financially supported surface water monitoring can be used to understand and manage a range of stressors and societal concerns. Using scientifically sound adaptive monitoring principles to balance continuity and change has ensured long-time series and the capability to address new questions over time. PMID:25403966

  6. Mimicking Nonequilibrium Steady States with Time-Periodic Driving

    NASA Astrophysics Data System (ADS)

    Raz, Oren; Subasi, Yigit; Jarzynski, Christopher

    Under static conditions, a system satisfying detailed balance generically relaxes to an equilibrium state in which there are no currents: to generate persistent currents, either detailed balance must be broken or the system must be driven in a time-dependent manner. A stationary system that violates detailed balance evolves to a nonequilibrium steady state (NESS) characterized by fixed currents. Conversely, a system that satisfies instantaneous detailed balance but is driven by the time-periodic variation of external parameters - also known as a stochastic pump (SP) - reaches a periodic state with non-vanishing currents. In both cases, these currents are maintained at the cost of entropy production. Are these two paradigmatic scenarios effectively equivalent? For discrete-state systems we establish a mapping between NESS and SP. Given a NESS characterized by a particular set of stationary probabilities, currents and entropy production rates, we show how to construct a SP with exactly the same (time-averaged) values. The mapping works in the opposite direction as well. These results establish a proof of principle: they show that SP are able to mimic the behavior of NESS, and vice-versa, within the theoretical framework of discrete-state stochastic thermodynamics.

  7. Mimicking Nonequilibrium Steady States with Time-Periodic Driving

    NASA Astrophysics Data System (ADS)

    Raz, O.; Subaşı, Y.; Jarzynski, C.

    2016-04-01

    Under static conditions, a system satisfying detailed balance generically relaxes to an equilibrium state in which there are no currents. To generate persistent currents, either detailed balance must be broken or the system must be driven in a time-dependent manner. A stationary system that violates detailed balance evolves to a nonequilibrium steady state (NESS) characterized by fixed currents. Conversely, a system that satisfies instantaneous detailed balance but is driven by the time-periodic variation of external parameters—also known as a stochastic pump (SP)—reaches a periodic state with nonvanishing currents. In both cases, these currents are maintained at the cost of entropy production. Are these two paradigmatic scenarios effectively equivalent? For discrete-state systems, we establish a mapping between nonequilibrium stationary states and stochastic pumps. Given a NESS characterized by a particular set of stationary probabilities, currents, and entropy production rates, we show how to construct a SP with exactly the same (time-averaged) values. The mapping works in the opposite direction as well. These results establish a proof of principle: They show that stochastic pumps are able to mimic the behavior of nonequilibrium steady states, and vice versa, within the theoretical framework of discrete-state stochastic thermodynamics. Nonequilibrium steady states and stochastic pumps are often used to model, respectively, biomolecular motors driven by chemical reactions and artificial molecular machines steered by the variation of external, macroscopic parameters. Our results loosely suggest that anything a biomolecular machine can do, an artificial molecular machine can do equally well. We illustrate this principle by showing that kinetic proofreading, a NESS mechanism that explains the low error rates in biochemical reactions, can be effectively mimicked by a constrained periodic driving.

  8. (abstract) Short Time Period Variations in Jupiter's Synchrotron Radiation

    NASA Technical Reports Server (NTRS)

    Bolton, S. J.; Klein, M. J.; Gulkis, S.; Foster, R.; Heiles, C.; Pater, I. de

    1994-01-01

    The long term time variability of Jupiter's synchrotron radiation on yearly time scales has been established for some time. For many years, theorists have speculated about the effects variations in the solar wind, solar flux, Io, the Io torus, and Jupiter's magnetic field have on the ultra-relativistic electron population responsible for the emission. Early observational results suggested the additional possibility of a short term time variability, on timescales of days to weeks. In 1989 a program designed to investigate the existence of short term time variability using the 85 foot Hat Creek radio telescope operating at 1400 MHz was initiated. The availability of a dedicated telescope provided the opportunity, for the first time, to obtain numerous observations over the full Jupiter rotation period. These and future observations will enable two important studies, characterization and confirmation of possible short term variations, and the investigation of the stability of Jupiter's synchrotron emission beaming curve. Analysis of Hat Creek observations and early results from the Maryland Point Naval research Laboratory will be presented.

  9. A 50-Year Journey to Cure Childhood Acute Lymphoblastic Leukemia

    PubMed Central

    Pui, Ching-Hon; Evans, William E.

    2013-01-01

    The 50th anniversary of Seminars in Hematology coincides with the 50th of St. Jude Children’s Research Hospital, and both milestones are inexorably linked to studies contributing to the cure of childhood acute lymphoblastic leukemia (ALL). We thought it fitting, therefore, to mark these events by traveling back in time to point out some of the achievements, institutions, study groups and individuals that have made cure of childhood ALL a reality. In many instances, progress was driven by new ideas, while in others it was driven by new experimental tools that allowed more precise assessment of the biology of leukemic blasts and their utility in selecting therapy. We also discuss a number of contemporary advances that point the way to exciting future directions. Whatever pathways are taken, a clear challenge will be to use emerging genome-based or immunologic-based treatment options in ways that will enhance, rather than duplicate or compromise, recent gains in outcome with classic cytotoxic chemotherapy. The theme of this journey serves as a reminder of the chief ingredient of any research directed to a catastrophic disease such as ALL. It is the audacity of a small group of investigators who confronted a childhood cancer with the goal of cure, not palliation, as their mindset. PMID:23953334

  10. Reflections on leadership in healthcare: the past 50 years.

    PubMed

    Smith, Robert

    2012-01-01

    Leadership in the hospital sector has been characterized by a state of change since the early 1960s. Heavily influenced by the emergence of the principles of the Canadian health system, leadership at the time was shaped in many ways by the post-World War II construction boom. It was significantly impacted by the developing professional unions in the clinical professions and the resultant and conflicted labour relations of the 60s and 70s. The environment of leadership was in those days predominantely a transactional style, and was frequently confrontational. But the many leaders of Canada's hospitals were also characterized by a caring cadre of often-colourful personalities who challenged, debated and strove to ensure adequate funding and a harmony among the diverse clinical, community and political interests confronting their organizations. The major restructuring of an ever-more expensive health system has set the stage for substantial innovation and reform as the leaders in the system integrate new technologies, personalized pharmaceuticals, devolving scopes of practice and entrepreneurial opportunities related to incentive funding. The development of leadership competencies such as the Leaders for Life framework across the health workforce will be essential to successfully guide our health delivery system into the future. PMID:23107907

  11. How the World Survived the Population Bomb: Lessons From 50 Years of Extraordinary Demographic History

    PubMed Central

    Lam, David

    2012-01-01

    The world population will reach 7 billion in late 2011, a demographic milestone that is causing renewed attention to the challenges caused by population growth. This article looks at the last 50 years of demographic change, one of the most extraordinary periods in demographic history. During this period, world population grew at rates that have never been seen before and will almost surely never be seen again. There were many concerns about the potential impact of rapid population growth in the 1960s, including mass starvation in countries such as India, depletion of nonrenewable resources, and increased poverty in low-income countries. The actual experience was very different. World food production increased faster than world population in every decade since the 1960s, resource prices fell during most of the period, and poverty declined significantly in much of the developing world. The article considers the economic and demographic explanations for the surprising successes of this important period in demographic history. It also looks at regions that have been less successful, especially Africa, and at the lessons for dealing with the important challenges that still remain. PMID:22005884

  12. The Challenges and Achievements in 50 Years of Human Spaceflight

    NASA Astrophysics Data System (ADS)

    Hawley, Steven A.

    2012-01-01

    On April 12, 1961 the era of human spaceflight began with the orbital flight of Cosmonaut Yuri Gagarin. On May 5, 1961 The United States responded with the launch of Alan Shepard aboard Freedom 7 on the first flight of Project Mercury. The focus of the first 20 years of human spaceflight was developing the fundamental operational capabilities and technologies required for a human mission to the Moon. The Mercury and Gemini Projects demonstrated launch and entry guidance, on-orbit navigation, rendezvous, extravehicular activity, and flight durations equivalent to a round-trip to the Moon. Heroes of this epoch included flight directors Chris Kraft, Gene Kranz, and Glynn Lunney along with astronauts like John Young, Jim Lovell, Tom Stafford, and Neil Armstrong. The "Race to the Moon” was eventually won by the United States with the landing of Apollo 11 on July 20, 1969. The Apollo program was truncated at 11 missions and a new system, the Space Shuttle, was developed which became the focus of the subsequent 30 years. Although never able to meet the flight rate or cost promises made in the 1970s, the Shuttle nevertheless left a remarkable legacy of accomplishment. The Shuttle made possible the launch and servicing of the Hubble Space Telescope and diverse activities such as life science research and classified national security missions. The Shuttle launched more than half the mass ever put into orbit and its heavy-lift capability and large payload bay enabled the on-orbit construction of the International Space Station. The Shuttle also made possible spaceflight careers for scientists who were not military test pilots - people like me. In this talk I will review the early years of spaceflight and share my experiences, including two missions with HST, from the perspective of a five-time flown astronaut and a senior flight operations manager.

  13. Polymer dynamics in time-dependent periodic potentials

    NASA Astrophysics Data System (ADS)

    Kauttonen, Janne; Merikoski, Juha; Pulkkinen, Otto

    2008-06-01

    The dynamics of a discrete polymer in time-dependent external potentials is studied with the master equation approach. We consider both stochastic and deterministic switching mechanisms for the potential states and give the essential equations for computing the stationary-state properties of molecules with internal structure in time-dependent periodic potentials on a lattice. As an example, we consider standard and modified Rubinstein-Duke polymers and calculate their mean drift and effective diffusion coefficient in the two-state nonsymmetric flashing potential and symmetric traveling potential. Rich nonlinear behavior of these observables is found. By varying the polymer length, we find current inversions caused by the rebound effect that is only present for molecules with internal structure. These results depend strongly on the polymer type. We also notice increased transport coherence for longer polymers.

  14. Backwards and Forwards: 50 years of the Education Group

    NASA Astrophysics Data System (ADS)

    2000-01-01

    The Education Group of the Institute of Physics celebrated its 50th anniversary by dedicating its annual 16 - 19 Day to a conference entitled Post-16 Physics: Looking forward, learning from the past. This attracted an audience of 50 or so nostalgia-seekers on Saturday 13 November at the Portland Place HQ. Philip Britton (Chair of the Education Group) began the proceedings in his usual pawky way by challenging members to identify the year in which some hardy topics were first addressed. A key trend in titles was the movement from problem to challenge . He looked forward to the time when success was a keynote word. Few identified Physics in Industry with the year of the deepest recession of the Thatcher Era. Tim Akrill (Chief A-level Physics Examiner for Edexcel) reminded us that A-levels were just about as old as the Education Group before taking us on an informative and entertaining tour of Assessment and Examinations through the Ages . Things have indeed become more complex since the very first written examination of 6th century China, when the only question, set every year, was: `Write down everything you know'. In 1951 an A-level physics paper gave a choice of six out of twelve questions and appeared in an A5 booklet of perhaps as many as four pages. The satisfying thump of a kilogram mass of current Edexcel A-level physics papers resounded through the room as he dropped them on a table. In those innocent days all questions followed the DDC format: define, describe, calculate . `Question spotting' was an art (or science) assiduously developed by teachers, as Lees' Disk alternated with Searle's Bar with less than exciting regularity. Have standards fallen? He thought not. At Edexcel they still get about 4000 candidates getting the higher grades, a number that has stayed the same for some 20 years. He singled out Nuffield Advanced Physics as being responsible for the greatest innovations in exam style since, well, the Chinese really. Styles such as Practical

  15. Effects of 50-years unmanaged water resource in Southern Tuscany coastal plains (Italy)

    NASA Astrophysics Data System (ADS)

    Rossetto, R.; Debolini, M.; Galli, M. A.; Bonari, E.

    2012-04-01

    original 4 Mm3. Having a reduced access to water resources, most of the farms during the 90's moved to more efficient water uses (drip irrigation) to save crops from leaf burns or switched to less-water-demanding, but less profitable crops. As a consequence, less competitive areas in the production-distribution chain suffered aquifer' salinisation and were progressively abandoned. As far as drinking water supply, the area is facing water scarcity during the summer period; desalination plants are planned. In one of the plain the water utility pumps out salinised groundwater that is then desalinized with an obvious increase in energy consumption. Although water management needs have grown during the last 50 years and several studies outlined the importance of planning this resource, conflicts among stakeholders and political issues make such problems of difficult solution. Today large dam building seems to be quite unreliable both because of the construction time and the financial issues related. At the same time feasible projects, driven also by innovative and more profitable agricultural development, call for wastewater reuse and artificial aquifer recharge starting at least from pilot tests in priority areas.

  16. Langevin Dynamics with Space-Time Periodic Nonequilibrium Forcing

    NASA Astrophysics Data System (ADS)

    Joubaud, R.; Pavliotis, G. A.; Stoltz, G.

    2015-01-01

    We present results on the ballistic and diffusive behavior of the Langevin dynamics in a periodic potential that is driven away from equilibrium by a space-time periodic driving force, extending some of the results obtained by Collet and Martinez in (J Math Biol, 56(6):765-792 2008). In the hyperbolic scaling, a nontrivial average velocity can be observed even if the external forcing vanishes in average. More surprisingly, an average velocity in the direction opposite to the forcing may develop at the linear response level—a phenomenon called negative mobility. The diffusive limit of the non-equilibrium Langevin dynamics is also studied using the general methodology of central limit theorems for additive functionals of Markov processes. To apply this methodology, which is based on the study of appropriate Poisson equations, we extend recent results on pointwise estimates of the resolvent of the generator associated with the Langevin dynamics. Our theoretical results are illustrated by numerical simulations of a two-dimensional system.

  17. Desensitization to media violence over a short period of time.

    PubMed

    Fanti, Kostas A; Vanman, Eric; Henrich, Christopher C; Avraamides, Marios N

    2009-01-01

    This study investigated the desensitization to violence over a short period of time. Participants watched nine violent movie scenes and nine comedy scenes, and reported whether they enjoyed the violent or comedy scenes and whether they felt sympathetic toward the victim of violence. Using latent growth modeling, analyses were carried out to investigate how participants responded to the different scenes across time. The findings of this study suggested that repeated exposure to media violence reduces the psychological impact of media violence in the short term, therefore desensitizing viewers to media violence. As a result, viewers tended to feel less sympathetic toward the victims of violence and actually enjoy more the violence portrayed in the media. Additionally, desensitization to media violence was better represented by a curvilinear pattern, whereas desensitization to comedy scenes was better represented by a linear pattern. Finally, trait aggression was not related to the pattern of change over time, although significant effects were found for initial reports of enjoyment and sympathy. PMID:19172659

  18. Relaxation Characteristics of 828 DGEBA Epoxy Over Long Time Periods

    NASA Astrophysics Data System (ADS)

    Hoo, Jasmine; Reprogle, Riley C.; Wisler, Brian; Arechederra, Gabriel K.; McCoy, John D.; Kropka, Jamie M.; Long, Kevin N.

    The mechanical relaxation response in uniaxial compression of a diglycidyl ether of bisphenol-A epoxy was studied over long time periods. The epoxy, 828DEA, was Epon 828 cured with diethanolamine (DEA). A sample was compressed at constant strain rate and held at various strain levels for days to allow the sample to relax. The sample was then compressed further and held once more. The relaxation curves were fit with a stretched exponential function. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  19. Swimming and transport of bacteria in time-periodic flows

    NASA Astrophysics Data System (ADS)

    Winter, Rebecca; Patteson, Alison; Gagnon, David; Arratia, Paulo

    The transport of bacteria can be highly influenced by external flows in oceans, rivers, and intestinal tracts. This has implications in biological systems for the performance of major biological processes, such as biofilm formation. In this study, we experimentally investigate the aggregation and transport of swimming Vibrio cholerae bacteria in time-periodic flows. Bacteria are placed in a well-characterized flow, and bacterial concentrations are recorded for a range of Reynolds numbers (Re) that spans two orders of magnitude, from 0.1 to 10. It is generally found that bacteria deplete from regions of high deformation rate and accumulate near vortices. This phenomenon seems to be dictated by a combination of bacterial activity and background flow vorticity. R.W. supported by NSF-GRFP.

  20. The Last 50 Years: Mismeasurement and Mismanagement Are Impeding Scientific Research.

    PubMed

    Lawrence, Peter A

    2016-01-01

    In the last 50 years, there have been many changes to the substance, conduct, and style of research. Many of these changes have proved disastrous to the life of scientists and to science itself. As a consequence, the near-romantic spirit of adventure and exploration that inspired young scientists of my own and earlier generations has become tarnished. Now, many of us feel beleaguered by bureaucrats and by politicians: they affect our lives profoundly, apparently without an understanding of the way discoveries are made or of the nature of science itself. The core purposes of universities, teaching and research, are being eroded by excessive administration. The number and locations of our publications are counted up like beans and the outcomes are used to rank us, one against another; a process of evaluation that has recast the purposes of publication. Applying for grants takes far too much time from a young scientist's life. PMID:26970645

  1. The Last 50 Years: Mismeasurement and Mismanagement Are Impeding Scientific Research

    PubMed Central

    Lawrence, Peter A.

    2016-01-01

    In the last 50 years, there have been many changes to the substance, conduct, and style of research. Many of these changes have proved disastrous to the life of scientists and to science itself. As a consequence, the near-romantic spirit of adventure and exploration that inspired young scientists of my own and earlier generations has become tarnished. Now, many of us feel beleaguered by bureaucrats and by politicians: they affect our lives profoundly, apparently without an understanding of the way discoveries are made or of the nature of science itself. The core purposes of universities, teaching and research, are being eroded by excessive administration. The number and locations of our publications are counted up like beans and the outcomes are used to rank us, one against another; a process of evaluation that has recast the purposes of publication. Applying for grants takes far too much time from a young scientist's life. PMID:26970645

  2. The psychological impact of a catastrophic earthquake: a retrospective study 50 years after the event.

    PubMed

    Lazaratou, Helen; Paparrigopoulos, Thomas; Galanos, Gerassimos; Psarros, Constantinos; Dikeos, Dimitris; Soldatos, Constantin

    2008-04-01

    Aim of the present study was to retrospectively assess the impact of a catastrophic earthquake in a sample of 121 survivors, 50 years after the event. Mean age +/- SD of the responders was 72.2 +/- 6.1 years. The majority of the victims (78%) acknowledged a strong overall impact of the earthquake on their lives, and almost all of them had intense recollection of the event at its anniversary. The most frequent symptom during the 6 months after the earthquake was persistent remembering or "reliving" of the event; women had considerably more often recurrent dreams of the earthquake and distress than did men. Women and young adults at the time of the earthquake appear to be the most vulnerable groups regarding the psychological effects of the event. PMID:18414131

  3. A reflection on the first 50 years of Water Resources Research

    NASA Astrophysics Data System (ADS)

    Rajaram, Harihar; Bahr, Jean M.; Blöschl, Günter; Cai, Ximing; Scott Mackay, D.; Michalak, Anna M.; Montanari, Alberto; Sanchez-Villa, Xavier; Sander, Graham

    2015-10-01

    The year 2015 marks the 50th anniversary of Water Resources Research (WRR), which was founded in 1965. More than 15,000 papers have been published in WRR since its inception, and these papers have been cited more than 430,000 times. The history of hydrology and the water sciences are also reflected in WRR, which has served as a premier publication outlet and instigator of scientific growth over the last 50 years. The legacy of WRR provides a strong scientific foundation for the hydrology community to rise to the challenges of sustainable water resources management in a future where dramatic environmental change and increasing human population are expected to stress the world's water resources from local to global scales.

  4. 14 CFR 221.190 - Time for filing and computation of time periods.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Time for filing and computation of time periods. 221.190 Section 221.190 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.190...

  5. 14 CFR 221.190 - Time for filing and computation of time periods.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Time for filing and computation of time periods. 221.190 Section 221.190 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.190...

  6. 14 CFR 221.190 - Time for filing and computation of time periods.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Time for filing and computation of time periods. 221.190 Section 221.190 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.190...

  7. 14 CFR 221.190 - Time for filing and computation of time periods.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Time for filing and computation of time periods. 221.190 Section 221.190 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.190...

  8. 14 CFR 221.190 - Time for filing and computation of time periods.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Time for filing and computation of time periods. 221.190 Section 221.190 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.190...

  9. 43 CFR 3207.5 - What terms (time periods) apply to my lease?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... LEASING Lease Terms and Extensions § 3207.5 What terms (time periods) apply to my lease? Your lease may include a number of different time periods. Not every time period applies to every lease. These periods... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false What terms (time periods) apply to...

  10. Exploring the dynamics of agricultural climatic resource utilization of spring maize over the past 50 years in Northeast China

    NASA Astrophysics Data System (ADS)

    Zhao, Junfang; Guo, Jianping; Mu, Jia; Xu, Yanhong

    Exploring the dynamics of the utilization of agricultural climatic resources (i.e., environmental factors that affect crop productivity such as light, temperature, and water) can provide a theoretical basis for modifying agricultural practices and distributions of agricultural production in the future. Northeast China is one of the major agricultural production areas in China and also an obvious region of climatic warming. We were motivated to analyze the utilization dynamics of agricultural climatic resource during spring maize cultivation from 1961 to 2010 in Northeast China. To understand these dynamics, we used the daily data from 101 meteorological stations in Northeast China between 1961 and 2010. The demands on agricultural climatic resources in Northeast China imposed by the cultivation of spring maize were combined and agricultural climatic suitability theory was applied. The growth period of spring maize was further detailedly divided into four stages: germination to emergence, emergence to jointing, jointing to tasseling, and tasseling to maturity. The average resource utilization index was established to evaluate the effects. Over the past five decades, Northeast China experienced increases in daily average temperature of 0.246 °C every decade during the growing season (May-September). At the same time, strong fluctuating decreases were observed in average total precipitation of 8.936 mm every decade and an average sunshine hour of 0.122 h every decade. Significant temporal and spatial changes occurred in K from 1961 to 2010. The K showed decreasing trends in Liaoning province and increasing trends in Jilin and especially in Heilongjiang province, which increased by 0.11. Spatial differences were visible in different periods, and the most obvious increase was found in the period 2001-2010. The areas with high values of K shifted northeastward over the past 50 years, indicating more efficient use of agricultural climatic resources in Northeast China.

  11. Social Network Analysis of 50 Years of International Collaboration in the Research of Educational Technology

    ERIC Educational Resources Information Center

    Guo, Shesen; Zhang, Ganzhou; Guo, Yufei

    2016-01-01

    The definition of the field of educational technology has evolved over 50 years. New inventions and economic globalization increasingly facilitate people's communication for exchange of ideas and collaboration. This work attempts to describe international research collaboration in educational technology for the past 50 years. This article intends…

  12. Report of the Minnesota Department of Education Survey of School Buildings: 50 Years and Older.

    ERIC Educational Resources Information Center

    Minnesota State Dept. of Education, St. Paul.

    Findings of a study that determined the physical conditions of Minnesota's public school buildings 50 years and older are presented in this report. Data were obtained from a survey that was distributed to 367 school districts that have 614 buildings 50 years and older. Responses were received from 398 buildings in 242 school districts. Findings…

  13. Disease Burden Due to Herpes Zoster among Population Aged ≥50 Years Old in China: A Community Based Retrospective Survey

    PubMed Central

    Yin, Dapeng; Liu, Yanmin; Huang, Zhuoying; Xu, Jianfang; Ma, Yujie; Tu, Qiufeng; Li, Qi; Wang, Huaqing

    2016-01-01

    Objective To understand the disease burden due to Herpes Zoster (HZ) among people aged ≥50 years old in China and provide baseline data for future similar studies, and provide evidence for development of herpes zoster vaccination strategy. Methods Retrospective cohort study was conducted in 4 townships and one community. A questionnaire was used to collect information on incidence and cost of HZ among people aged ≥ 50 years old. Results The cumulative incidence rate was 22.6/1,000 among people aged ≥ 50 years old. The average annual incidence rate of HZ was 3.43/1,000 among people aged ≥ 50 years old in 2010–2012. Cumulative incidence and average annual incidence rate increased with age: the cumulative incidence of HZ among people aged ≥ 80 years old was 3.34 times of that among 50- years old (52.3/1000vs15.7/1,000); average annual incidence rate rises from 2.66/1,000 among 50- years old to 8.55/1,000 among 80- year old. Cumulative incidence and average annual incidence rate for females were higher than that for males (cumulative incidence, 26.5/1000vs18.7/1,000; annual incidence rate, 3.95/1000vs2.89/1,000). Cumulative incidence and average annual incidence rate in urban were higher than in rural (cumulative incidence, 39.5/1000vs 17.2/1,000; annual incidence rate, 7.65/1000vs2.06/1,000). The hospitalization rate of HZ was 4.53%. And with the increase of age, the rate has an increasing trend. HZ costs 945,709.5 RMB in total, corresponding to 840.6 RMB per patient with a median cost of 385 RMB (interquartile range 171.7–795.6). Factors associated with cost included the first onset year, area, whether hospitalized and whether sequelae left. Conclusion Incidence rate, complications, hospitalization rate and average cost of HZ increase with age. We recommend that the HZ vaccinations should target people aged ≥50 years old if Zoster vaccine is licensed in China. PMID:27055179

  14. Almost periodic dynamics for impulsive delay neural networks of a general type on almost periodic time scales

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Agarwal, Ravi P.

    2016-07-01

    In this paper, we improve the new concepts of almost periodic time scales addressed in 2014 to introduce the new concepts of piecewise almost periodic functions. Then we establish some first results for the existence and exponential stability of almost periodic solution for a general type of delay neural networks with impulsive effects. The approaches are based on contraction principle and Gronwall-Bellman's inequality. In addition, the numerical example and simulations are provided to illustrate our time scale methods are feasible and effective. The obtained results are more general and comprehensive than the results obtained on periodic time scales before.

  15. Alumina-alumina hip replacement in patients younger than 50 years old.

    PubMed

    Sedel, L; Nizard, R S; Kerboull, L; Witvoet, J

    1994-01-01

    From April 1977 to December 1990, 131 total hip arthroplasties were performed on 113 patients younger than 50 years of age (median, 41 years); 64 were men and 49 women. The majority were active people. Sixty-six hips had no previous operations, and 33 had at least one previous arthroplasty. The femoral component was a cemented collared titanium alloy stem, and alumina socket was cemented for 99 hips and press-fit for 32. The mean follow-up period was five years, with 32 hips followed for more than ten years. Revision arthroplasty was considered as a failure. Survivorship analysis depicted a 97.5% rate of survival at five years, an 89.4% rate at ten years, and an 86.2% at 11 years. Nine revisions were performed: one experienced a femoral head rupture after three years, one had bipolar loosening, one experienced femoral cystic formation, and six were revised for acetabular cup loosening, all from the cemented group. Two revisions occurred on the same patient. No stem revision was necessary before ten years. Only one of these revisions was required in patients aged 40 or younger (64 patients). Alumina-alumina friction is an extremely interesting phenomenon in young patients, and could be related to the low wear debris production. PMID:8118972

  16. Global nitrogen budgets in cereals: A 50-year assessment for maize, rice, and wheat production systems

    PubMed Central

    Ladha, J. K.; Tirol-Padre, A.; Reddy, C. K.; Cassman, K. G.; Verma, Sudhir; Powlson, D. S.; van Kessel, C.; de B. Richter, Daniel; Chakraborty, Debashis; Pathak, Himanshu

    2016-01-01

    Industrially produced N-fertilizer is essential to the production of cereals that supports current and projected human populations. We constructed a top-down global N budget for maize, rice, and wheat for a 50-year period (1961 to 2010). Cereals harvested a total of 1551 Tg of N, of which 48% was supplied through fertilizer-N and 4% came from net soil depletion. An estimated 48% (737 Tg) of crop N, equal to 29, 38, and 25 kg ha−1 yr−1 for maize, rice, and wheat, respectively, is contributed by sources other than fertilizer- or soil-N. Non-symbiotic N2 fixation appears to be the major source of this N, which is 370 Tg or 24% of total N in the crop, corresponding to 13, 22, and 13 kg ha−1 yr−1 for maize, rice, and wheat, respectively. Manure (217 Tg or 14%) and atmospheric deposition (96 Tg or 6%) are the other sources of N. Crop residues and seed contribute marginally. Our scaling-down approach to estimate the contribution of non-symbiotic N2 fixation is robust because it focuses on global quantities of N in sources and sinks that are easier to estimate, in contrast to estimating N losses per se, because losses are highly soil-, climate-, and crop-specific. PMID:26778035

  17. Convergence Time towards Periodic Orbits in Discrete Dynamical Systems

    PubMed Central

    San Martín, Jesús; Porter, Mason A.

    2014-01-01

    We investigate the convergence towards periodic orbits in discrete dynamical systems. We examine the probability that a randomly chosen point converges to a particular neighborhood of a periodic orbit in a fixed number of iterations, and we use linearized equations to examine the evolution near that neighborhood. The underlying idea is that points of stable periodic orbit are associated with intervals. We state and prove a theorem that details what regions of phase space are mapped into these intervals (once they are known) and how many iterations are required to get there. We also construct algorithms that allow our theoretical results to be implemented successfully in practice. PMID:24736594

  18. Convergence time towards periodic orbits in discrete dynamical systems.

    PubMed

    San Martín, Jesús; Porter, Mason A

    2014-01-01

    We investigate the convergence towards periodic orbits in discrete dynamical systems. We examine the probability that a randomly chosen point converges to a particular neighborhood of a periodic orbit in a fixed number of iterations, and we use linearized equations to examine the evolution near that neighborhood. The underlying idea is that points of stable periodic orbit are associated with intervals. We state and prove a theorem that details what regions of phase space are mapped into these intervals (once they are known) and how many iterations are required to get there. We also construct algorithms that allow our theoretical results to be implemented successfully in practice. PMID:24736594

  19. Attitudes to and experience of dental care among 50-year-olds in two Swedish counties.

    PubMed

    Unell, L; Söderfeldt, B; Halling, A; Birkhed, D

    1999-01-01

    The aim of this study was to investigate attitudes to and experiences of dental care in a population, born 1942. The following items were studied: opinions of general and oral health, attitudes to and experiences of dental care, dental care habits, experiences of latest visit to a dentist, tobacco habits and use of various dental hygiene articles. A cross-sectional mail questionnaire was sent in 1992 to all 50-year-olds in two Swedish counties, Orebro and Ostergotland, totally 8888 persons; the response rate was 71%. Of the population 89%, indicated good health. Satisfaction with dental care was high, 94%. 26% stated attendance to a dentist twice or more per year, and 64% at least once a year. As to expenses, 78% paid less than 1000 SEK the last year. Concerning the latest visit, 38% reported painless treatment, 37% no inconvenience, and 55% good care. The duration of the latest visit included on an average 27 min in travel time, 7 min in waiting time and 27 min in treatment time. Information about oral hygiene was given to 29% and about cost for treatment to 47% of the interviewed. There were 28% daily smokers. Snuff was daily used by 10% of the males. Toothbrushing twice a day with fluoride toothpaste seemed to be the standard oral hygiene procedure and was reported by 80% of the respondents. PMID:10431344

  20. Logic Model Checking of Time-Periodic Real-Time Systems

    NASA Technical Reports Server (NTRS)

    Florian, Mihai; Gamble, Ed; Holzmann, Gerard

    2012-01-01

    In this paper we report on the work we performed to extend the logic model checker SPIN with built-in support for the verification of periodic, real-time embedded software systems, as commonly used in aircraft, automobiles, and spacecraft. We first extended the SPIN verification algorithms to model priority based scheduling policies. Next, we added a library to support the modeling of periodic tasks. This library was used in a recent application of the SPIN model checker to verify the engine control software of an automobile, to study the feasibility of software triggers for unintended acceleration events.

  1. 50 years of the K-BKZ constitutive relation in polymer rheology and processing

    NASA Astrophysics Data System (ADS)

    Mitsoulis, E.

    2014-05-01

    The K-BKZ constitutive model is now 50 years old. The article reviews the connections of the model and its variants with continuum mechanics, presenting an up-to-date recap of research and major findings in the open literature. An historical perspective is given on developments in the last 50 years of the K-BKZ model and its use in rheology and polymer processing.

  2. 29 CFR 4000.43 - How do I compute a time period?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false How do I compute a time period? 4000.43 Section 4000.43..., ISSUANCE, COMPUTATION OF TIME, AND RECORD RETENTION Computation of Time § 4000.43 How do I compute a time period? (a) In general. If you are computing a time period to which this part applies, whether you...

  3. 29 CFR 4000.43 - How do I compute a time period?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 9 2011-07-01 2011-07-01 false How do I compute a time period? 4000.43 Section 4000.43..., ISSUANCE, COMPUTATION OF TIME, AND RECORD RETENTION Computation of Time § 4000.43 How do I compute a time period? (a) In general. If you are computing a time period to which this part applies, whether you...

  4. 29 CFR 4000.43 - How do I compute a time period?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 9 2012-07-01 2012-07-01 false How do I compute a time period? 4000.43 Section 4000.43..., ISSUANCE, COMPUTATION OF TIME, AND RECORD RETENTION Computation of Time § 4000.43 How do I compute a time period? (a) In general. If you are computing a time period to which this part applies, whether you...

  5. 29 CFR 4000.43 - How do I compute a time period?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 9 2014-07-01 2014-07-01 false How do I compute a time period? 4000.43 Section 4000.43..., ISSUANCE, COMPUTATION OF TIME, AND RECORD RETENTION Computation of Time § 4000.43 How do I compute a time period? (a) In general. If you are computing a time period to which this part applies, whether you...

  6. 29 CFR 4000.43 - How do I compute a time period?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 9 2013-07-01 2013-07-01 false How do I compute a time period? 4000.43 Section 4000.43..., ISSUANCE, COMPUTATION OF TIME, AND RECORD RETENTION Computation of Time § 4000.43 How do I compute a time period? (a) In general. If you are computing a time period to which this part applies, whether you...

  7. Burning invariant manifolds in time-periodic and time-aperiodic vortex flows

    NASA Astrophysics Data System (ADS)

    Gowen, Savannah; Solomon, Tom

    2014-11-01

    We present experiments that study reaction fronts in a flow composed of a single, translating vortex. The fronts are produced by the excitable Belousov-Zhabotinsky (BZ) chemical reaction, and the vortex flow is driven magnetohydrodynamically by a radial current in a thin fluid layer above a Nd-Fe-Bo magnet. The magnet is mounted on a pair of perpendicular translation stages, allowing for controlled, two-dimensional movement of the magnet and the resulting vortex. We study reaction fronts that pin to the vortex for time-independent flows (produced by moving the vortex with a constant velocity) and for time-periodic and time-aperiodic flows produced by oscillating the vortex laterally. The steady-state front shape is analyzed in terms of burning invariant manifolds (BIMs) that act as one-way barriers against any propagating reaction fronts. For time independent and time-periodic flows, the location of the BIMs are calculated numerically and are compared with experimental images of the pinned reaction fronts. We investigate extensions of this BIM approach for analyzing fronts in time-aperiodic flows. Supported by NSF Grants DMR-1004744, DMR-1361881 and PHY-1156964.

  8. Unsettled Times, Unsettled Prices: Periodical Price Survey 1997.

    ERIC Educational Resources Information Center

    Ketcham, Lee; Born, Kathleen

    1997-01-01

    Presents the results of the thirty-seventh annual periodical price survey conducted by "Library Journal". Highlights include canceling print subscriptions and electronic journals, cost trends by subject and by countries, prices for public and school libraries and for college and medium-sized university libraries, and budgeting for 1988. (LRW)

  9. Asymptotic stability on slow time scales from periodic systems

    SciTech Connect

    Persek, S.C.

    1981-08-01

    Asymptotic stability for a periodic system of ordinary differential equations with a small parameter is shown to follow from the stability of the corresponding iterated-average system. Applications are made to biological systems experiencing varying seasonal factors, to large scale dynamical systems that are principally irrotational and to nuclear reactor dynamics. 7 refs.

  10. Using travel times to simulate multi-dimensional bioreactive transport in time-periodic flows.

    PubMed

    Sanz-Prat, Alicia; Lu, Chuanhe; Finkel, Michael; Cirpka, Olaf A

    2016-04-01

    In travel-time models, the spatially explicit description of reactive transport is replaced by associating reactive-species concentrations with the travel time or groundwater age at all locations. These models have been shown adequate for reactive transport in river-bank filtration under steady-state flow conditions. Dynamic hydrological conditions, however, can lead to fluctuations of infiltration velocities, putting the validity of travel-time models into question. In transient flow, the local travel-time distributions change with time. We show that a modified version of travel-time based reactive transport models is valid if only the magnitude of the velocity fluctuates, whereas its spatial orientation remains constant. We simulate nonlinear, one-dimensional, bioreactive transport involving oxygen, nitrate, dissolved organic carbon, aerobic and denitrifying bacteria, considering periodic fluctuations of velocity. These fluctuations make the bioreactive system pulsate: The aerobic zone decreases at times of low velocity and increases at those of high velocity. For the case of diurnal fluctuations, the biomass concentrations cannot follow the hydrological fluctuations and a transition zone containing both aerobic and obligatory denitrifying bacteria is established, whereas a clear separation of the two types of bacteria prevails in the case of seasonal velocity fluctuations. We map the 1-D results to a heterogeneous, two-dimensional domain by means of the mean groundwater age for steady-state flow in both domains. The mapped results are compared to simulation results of spatially explicit, two-dimensional, advective-dispersive-bioreactive transport subject to the same relative fluctuations of velocity as in the one-dimensional model. The agreement between the mapped 1-D and the explicit 2-D results is excellent. We conclude that travel-time models of nonlinear bioreactive transport are adequate in systems of time-periodic flow if the flow direction does not change

  11. Using travel times to simulate multi-dimensional bioreactive transport in time-periodic flows

    NASA Astrophysics Data System (ADS)

    Sanz-Prat, Alicia; Lu, Chuanhe; Finkel, Michael; Cirpka, Olaf A.

    2016-04-01

    In travel-time models, the spatially explicit description of reactive transport is replaced by associating reactive-species concentrations with the travel time or groundwater age at all locations. These models have been shown adequate for reactive transport in river-bank filtration under steady-state flow conditions. Dynamic hydrological conditions, however, can lead to fluctuations of infiltration velocities, putting the validity of travel-time models into question. In transient flow, the local travel-time distributions change with time. We show that a modified version of travel-time based reactive transport models is valid if only the magnitude of the velocity fluctuates, whereas its spatial orientation remains constant. We simulate nonlinear, one-dimensional, bioreactive transport involving oxygen, nitrate, dissolved organic carbon, aerobic and denitrifying bacteria, considering periodic fluctuations of velocity. These fluctuations make the bioreactive system pulsate: The aerobic zone decreases at times of low velocity and increases at those of high velocity. For the case of diurnal fluctuations, the biomass concentrations cannot follow the hydrological fluctuations and a transition zone containing both aerobic and obligatory denitrifying bacteria is established, whereas a clear separation of the two types of bacteria prevails in the case of seasonal velocity fluctuations. We map the 1-D results to a heterogeneous, two-dimensional domain by means of the mean groundwater age for steady-state flow in both domains. The mapped results are compared to simulation results of spatially explicit, two-dimensional, advective-dispersive-bioreactive transport subject to the same relative fluctuations of velocity as in the one-dimensional model. The agreement between the mapped 1-D and the explicit 2-D results is excellent. We conclude that travel-time models of nonlinear bioreactive transport are adequate in systems of time-periodic flow if the flow direction does not change.

  12. Accurate frequency domain measurement of the best linear time-invariant approximation of linear time-periodic systems including the quantification of the time-periodic distortions

    NASA Astrophysics Data System (ADS)

    Louarroudi, E.; Pintelon, R.; Lataire, J.

    2014-10-01

    Time-periodic (TP) phenomena occurring, for instance, in wind turbines, helicopters, anisotropic shaft-bearing systems, and cardiovascular/respiratory systems, are often not addressed when classical frequency response function (FRF) measurements are performed. As the traditional FRF concept is based on the linear time-invariant (LTI) system theory, it is only approximately valid for systems with varying dynamics. Accordingly, the quantification of any deviation from this ideal LTI framework is more than welcome. The “measure of deviation” allows us to define the notion of the best LTI (BLTI) approximation, which yields the best - in mean square sense - LTI description of a linear time-periodic LTP system. By taking into consideration the TP effects, it is shown in this paper that the variability of the BLTI measurement can be reduced significantly compared with that of classical FRF estimators. From a single experiment, the proposed identification methods can handle (non-)linear time-periodic [(N)LTP] systems in open-loop with a quantification of (i) the noise and/or the NL distortions, (ii) the TP distortions and (iii) the transient (leakage) errors. Besides, a geometrical interpretation of the BLTI approximation is provided, leading to a framework called vector FRF analysis. The theory presented is supported by numerical simulations as well as real measurements mimicking the well-known mechanical Mathieu oscillator.

  13. Commentary on 50 years of research at the NBRL, Boston, Massachusetts.

    PubMed

    Valeri, C R; Giorgio, G R

    2016-02-01

    Research at the NBRL, Boston, MA over the past 50 years assessed the survival and function of RBC and platelets and the function of plasma clotting proteins. Liquid preserved RBC can be stored at 4 °C for only 2 weeks to maintain a 24-hour posttransfusion survival value of 75%, moderately impaired oxygen transport function after transfusion, exert a hemostatic effect, and increase the plasma volume. Liquid preserved platelets can be stored at room temperature with agitation for only 2 days to have acceptable in vivo survival 2 hours following transfusion, normal lifespan, and a hemostatic effect to reduce the bleeding time in thrombocytopenic patients. RBCs frozen with 40% W/V glycerol at -80 °C for at least 10 years, thawed, and deglycerolized in the Haemonetics ACP215 can be stored in Nutricel at 4 °C for 2 weeks with a 24-hour posttransfusion survival of 75%, moderately impaired oxygen transport function after transfusion, exert a hemostatic effect and increase the plasma volume. Leukoreduced single donor platelets treated with 6% DMSO, the supernatant DMSO removed prior to freezing at -80 °C for 2 years, thawed, and diluted with 0.9% NaCl or AB plasma have a bimodal population of platelets: one population has reduced in vivo survival, but increased hemostatic effect and the other has normal in vivo survival. AB plasma can be stored at -80 °C for at least 14 years, thawed, and stored at 4 °C for 24 hours with acceptable in vitro function of clotting proteins. The data reported by the NBRL, Boston, Mass. over the past 50 years and the 15-year experience by the Netherlands military now recommend that FDA, ARC, HHS and DOD should support the use of universal donor frozen group O Rh positive and group O Rh negative RBC, frozen group O platelets and frozen AB plasma from male donors. The frozen blood products will eliminate the severe adverse events of mortality and morbidity associated with the current FDA approved red blood cell products, platelet

  14. The changes of glaciers on northern Baikal ridges over 50 years using in-situ and remotely sensed observations

    NASA Astrophysics Data System (ADS)

    Ivanov, Egor; Alexander, Kitov

    2013-04-01

    All the glaciers lying over the Baikalsky and Barguzinsky ridges of Northern Baikal are small. They are located in hard-to-reach regions both for In-situ such and for remotely sensed observations. A researcher can reach glaciers only by using special alpine equipment. The deep ruggedness of hollows and the being of glaciers in the shade over a period of significant time prevent from remotely sensed observations. The Glaciers of Baikalsky ridge are not registered in the catalogue of the Eurasia glaciers since there are no data about the glaciers in the catalogue of the glaciers of USSR. In result of our expedition works and the analyzing of satellite photograph it was determined that the largest cirque glacier- Cherskogo sufficiently stable. Its retreat has been insignificantly in over 50 years - from 0.446 to 0.407 sq. km, id est on 8,7 %. The glaciers of Barguzinsky ridge are very poorly explored. IG SB RAS in 2011 year for the first time completed the expedition with the object of inventory of these ridge glaciers. This region is extremely difficult to approach. The space survey of ultrahigh resolution for the study area (0.5 m) was ordered before the start of the expedition. Also the accessible archive data of Landsat resolution by 15-30 meters have been received. The comparison of cartographical, distance and expedition data show essential retreat of most of glaciers and its degradation from cirque to slope glaciers. Discovered snow-glacial formations can be divided on 3 main groups: 1 -real glaciers; 2 - slope pendent glacier remains; 3 - permanent snow patches. The region is interesting because there practically are all the forms of little glaciations. In addition it can be observed not only glacier's degradation but their origins too. In the favorable year conditions the snow patches are increased with occupying of the basic of cirque bed and form the ice core and continue the formation of the cirque. The second group of glaciers has actually been reserved

  15. Non-labile silver species in biosolids remain stable throughout 50 years of weathering and ageing.

    PubMed

    Donner, E; Scheckel, K; Sekine, R; Popelka-Filcoff, R S; Bennett, J W; Brunetti, G; Naidu, R; McGrath, S P; Lombi, E

    2015-10-01

    Increasing commercial use of nanosilver has focussed attention on the fate of silver (Ag) in the wastewater release pathway. This paper reports the speciation and lability of Ag in archived, stockpiled, and contemporary biosolids from the UK, USA and Australia, and indicates that biosolids Ag concentrations have decreased significantly over recent decades. XANES revealed the importance of reduced-sulfur binding environments for Ag speciation in materials ranging from freshly produced sludge to biosolids weathered under ambient environmental conditions for more than 50 years. Isotopic dilution with (110 m)Ag showed that Ag was predominantly non-labile in both fresh and aged biosolids (13.7% mean lability), with E-values ranging from 0.3 to 60 mg/kg and 5 mM CaNO3 extractable Ag from 1.2 to 609 μg/kg (0.002-3.4% of the total Ag). This study indicates that at the time of soil application, biosolids Ag will be predominantly Ag-sulfides and characterised by low isotopic lability. PMID:26021819

  16. Incidence and Mortality after Distal Radius Fractures in Adults Aged 50 Years and Older in Korea

    PubMed Central

    2016-01-01

    The purpose of this study was to assess the incidence and mortality of distal radius fracture among patients 50 years of age and older with diagnosis code (ICD10; S52.5, S52.6) and treatment code using a nationwide claims database from 2008 to 2012. All patients were followed using patient identification code to identify deaths. Standardized mortality ratios (SMRs) of distal radius fracture were calculated based on age and gender-specific rates in the entire Korean population. The number of distal radius fractures increased by 54.2% over the 5-year study (48,145 in 2008 and 74,240 in 2012). The incidence of distal radius fracture increased from 367.4/100,000 in 2008 to 474.1/100,000 in 2012. The cumulative mortality rate over the first 12 months after distal radius fracture was decreased from 2.0% (968/48,145) in 2008 to 1.4% (1,045/74,240) in 2012. The mean year mortality over 5 years in men (2.6%, 1,279/50,128) over the first 12 months was 1.7-times higher than in women (1.5%, 3,952/257,045). The mean of SMR of distal radius fracture at 1 year post-fracture was 1.45 in men and 1.17 in women. This study using a nationwide database demonstrates that the distal radius fractures are increasing with a decreasing mortality in Korea. PMID:27051250

  17. Substantial glacier mass loss in the Tien Shan over the past 50 years

    NASA Astrophysics Data System (ADS)

    Farinotti, Daniel; Longuevergne, Laurent; Moholdt, Geir; Duethmann, Doris; Mölg, Thomas; Bolch, Tobias; Vorogushyn, Sergiy; Güntner, Andreas

    2015-09-01

    Populations in Central Asia are heavily dependent on snow and glacier melt for their water supplies. Changes to the glaciers in the main mountain range in this region, the Tien Shan, have been reported over the past decade. However, reconstructions over longer, multi-decadal timescales and the mechanisms underlying these variations--both required for reliable future projections--are not well constrained. Here we use three ensembles of independent approaches based on satellite gravimetry, laser altimetry, and glaciological modelling to estimate the total glacier mass change in the Tien Shan. Results from the three approaches agree well, and allow us to reconstruct a consistent time series of annual mass changes for the past 50 years at the resolution of individual glaciers. We detect marked spatial and temporal variability in mass changes. We estimate the overall decrease in total glacier area and mass from 1961 to 2012 to be 18 +/- 6% and 27 +/- 15%, respectively. These values correspond to a total area loss of 2,960 +/- 1,030 km2, and an average glacier mass-change rate of -5.4 +/- 2.8 Gt yr-1. We suggest that the decline is driven primarily by summer melt and, possibly, linked to the combined effects of general climatic warming and circulation variability over the north Atlantic and north Pacific.

  18. Aging in Prader-Willi syndrome: twelve persons over the age of 50 years.

    PubMed

    Sinnema, Margje; Schrander-Stumpel, Constance T R M; Maaskant, Marian A; Boer, Harm; Curfs, Leopold M G

    2012-06-01

    The life expectancy of persons with Prader-Willi syndrome (PWS) has increased in recent years. Because of the paucity of reports on older persons with PWS, the natural history, the onset, and type of age-related problems are poorly understood. Twelve persons with a genetically confirmed diagnosis of PWS aged over 50 years are described (4 deletion; 8 mUPD). Data on physical, behavioral, psychiatric, and aging characteristics were collected through semi-structured interviews with the individuals with PWS and their main carers. Cardiovascular diseases, diabetes, dermatological, and orthopedic problems were common physical complaints in older people with PWS. Functioning in activities of daily living, psychological functioning, physical functions, and care dependence were substantially worse in the older age group (50+) compared to the control group (18-49 years). Seven out of eight persons with mUPD had a history of psychiatric illness. Behavioral problems were observed in the older age group. Given the combination of age-related physical morbidity, physical appearance, behavioral and psychiatric problems, and functional decline in our cohort, we hypothesize that premature aging occurs in PWS. The care for older people with PWS requires a lifespan approach that recognizes the presence, progression, and consequences of specific morbidity. Special medical surveillance of people with PWS from 40 years onwards would ensure that intervention and support is offered with respect to specific areas of decline at the earliest possible time. PMID:22585395

  19. Air pollution in the last 50 years - From local to global

    NASA Astrophysics Data System (ADS)

    Fenger, Jes

    Air pollution in the industrialised world has in the last 50 years undergone drastic changes. Until after World War II the most important urban compound was sulphur dioxide combined with soot from the use of fossil fuels in heat and power production. When that problem was partly solved by cleaner fuels, higher stacks and flue gas cleaning in urban areas, the growing traffic gave rise to nitrogen oxides and volatile organic compounds and in some areas photochemical air pollution, which may be abated by catalytic converters. Lately the interest has centred on small particles and more exotic organic compounds that can be detected with new sophisticated analytical techniques. Simultaneously with the development in compounds, the time and geographical scale of interest have increased. First to transboundary air pollution, which in decades and on continents can degrade ecosystems, later to the depletion of the ozone layer and especially to the increasing greenhouse effect with climate change that will change the conditions for nature and mankind on the entire globe. The possibilities to study these large scale phenomena have been greatly enhanced by the development of electronic computers that can handle large data sets and calculate various scenarios. All these processes take place in the thin layer of gases around the Earth, the atmosphere. Although the abatement is often restricted to a single aspect, they are often connected and should when possible be treated as whole.

  20. 50 Years of Electronic Check Out and Launch Systems at Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Starr, Stanley O.

    2007-01-01

    When NASA was created in 1958 one of the elements incorporated into this new agency was the Army Ballistic Missile Agency (ABMA) in Huntsville, AL and its subordinate Missile Firing Laboratory (MFL) in Cape Canaveral. Under NASA, the MFL became the Launch Operations Directorate of the George C. Marshall Space Flight Center in Huntsville, but expanding operations in the build up to Apollo dictated that it be given the status of a full fledged Center in July, 1 962[ 1]. The next year it was renamed the John F. Kennedy Space Center (KS C) after the president whose vision transformed its first decade of operation. The ABMA was under the technical leadership of Dr. Werner Von Braun. The MEL was run by his deputy Dr. Kurt Debus, an electrical engineer whose experience in the field began in the early days of V-2 testing in war time Germany. In 1952 a group led by Debus arrived in Cape Canaveral to begin test launches of the new Redstone missile [2]. During the 50's, The MFL built several launch complexes and tested the Redstone, Jupiter and Jupiter C missiles. This small experienced team of engineers and technicians formed the seed from which has grown the KSC team of today. This article briefly reviews the evolution of the KSC electronic technologies for integration, check-out and launch of space vehicles and payloads during NASA's first 50 years.

  1. Estimating return periods of extreme values from relatively short time series of winds

    NASA Astrophysics Data System (ADS)

    Jonasson, Kristjan; Agustsson, Halfdan; Rognvaldsson, Olafur; Arfeuille, Gilles

    2013-04-01

    An important factor for determining the prospect of individual wind farm sites is the frequency of extreme winds at hub height. Here, extreme winds are defined as the value of the highest 10 minutes averaged wind speed with a 50 year return period, i.e. annual exceeding probability of 2% (Rodrigo, 2010). A frequently applied method to estimate winds in the lowest few hundred meters above ground is to extrapolate observed 10-meter winds logarithmically to higher altitudes. Recent study by Drechsel et al. (2012) showed however that this methodology is not as accurate as interpolating simulated results from the global ECMWF numerical weather prediction (NWP) model to the desired height. Observations of persistent low level jets near Colima in SW-Mexico also show that the logarithmic approach can give highly inaccurate results for some regions (Arfeuille et al., 2012). To address these shortcomings of limited, and/or poorly representative, observations and extrapolations of winds one can use NWP models to dynamically scale down relatively coarse resolution atmospheric analysis. In the case of limited computing resources one has typically to make a compromise between spatial resolution and the duration of the simulated period, both of which can limit the quality of the wind farm siting. A common method to estimate maximum winds is to fit an extreme value distribution (e.g. Gumbel, gev or Pareto) to the maximum values of each year of available data, or the tail of these values. If data are only available for a short period, e.g. 10 or 15 years, then this will give a rather inaccurate estimate. It is possible to deal with this problem by utilizing monthly or weekly maxima, but this introduces new problems: seasonal variation, autocorrelation of neighboring values, and increased discrepancy between data and fitted distribution. We introduce a new method to estimate return periods of extreme values of winds at hub height from relatively short time series of winds, simulated

  2. Incidence, Morbidity and Mortality in Patients Older than 50 Years with Second Hip Fracture in a Jeju Cohort Study

    PubMed Central

    Park, Yong-Geun; Jang, Sunmee

    2014-01-01

    Purpose Although the incidence of a second hip fracture is relatively well described, mortality and morbidity after a second hip fracture are seldom evaluated. The purpose of this study was to determine the incidence, morbidity, and mid-term mortality of a second hip fracture and evaluate the cause of death after a second hip fracture. Materials and Methods Information on patients older than 50 years, who sustained a subsequent hip fracture, were obtained from the records of eight Jeju Island hospitals between 2002 and 2011 to calculate the incidence, morbidity, and mortality of hip fractures in this age group. All patients were followed a minimum of 2 years. A systemic search for death certificates at the National Statistical Office was conducted for patients who were lost to follow-up. Results Of 2,055 hip fractures (419 men and 1,636 women), 98 were second hip fractures (13 men and 85 women) during the study period. The mean ages of the patients at the time of the first and second fractures were 78.8 and 80.8 years, respectively. The incidence of a subsequent hip fracture among the first hip fracture was 4.8%. Mean mortality rates at 6 months, 1 year, 2 years, and 5 years were 10.5%, 15.2%, 23.5%, and 42.0% respectively. Cumulative mortality after the second hip fracture at the 5 years follow-up was 41.8%. Conclusion Our results demonstrate that a secondary fracture prevention program is necessary to prevent second hip fractures in elderly patients.

  3. Evidence of bottom-up control of marine productivity in the Mediterranean Sea during the last 50 years

    NASA Astrophysics Data System (ADS)

    Macías, Diego; Garcia-Gorriz, Elisa; Piroddi, Chiara; Stips, Adolf

    2014-05-01

    The temporal dynamics of biogeochemical variables derived from a coupled 3D hydrodynamic-biogeochemical model of the entire Mediterranean Sea is evaluated during the last 50 years (1960 - 2010). Realistic atmospheric forcing and river discharge are used to force the dynamics of the coupled model system. The time evolutions of primary and secondary productions in the entire basin are assessed against available independent data on fisheries yields and catches per unit effort for the same time period. Concordant patterns are found in the time-series of all biological variables (from the model and from fisheries statistics), with low values at the beginning of the series, a later increase with maximum values reached at the end of the 1990's and a posterior stabilization or a small decline. Spectral analysis of the annual biological time-series reveals coincident low-frequency signals in all of them; the first, more energetic signal, peaks at 2000 while the second one (less energetic) presents maximum values at around 1982. Almost identical low-frequency signals are found in the nutrient loads of the main rivers of the basin and in the integrated (0-100 meters) mean nutrient concentrations in the marine ecosystem. Nitrate concentration shows an increasing trend up to 1998 with a later stabilization or a slight decline to present day values. This nitrate evolution seems to be driving the first low-frequency signal found in the biological time series. Phosphate, on the other hand, shows maximum concentrations around 1982 and a posterior sharp decline. This nutrient seems to be responsible for the second low-frequency signal observed in the biological time-series. Our analysis shows that the control of marine productivity (from plankton to fish) in the Mediterranean basin seem to be principally mediated through bottom-up processes that could be traced back to the characteristics of riverine discharges. Other types of control could not be excluded from our analysis (e

  4. Mortality in relation to smoking: 50 years' observations on male British doctors

    PubMed Central

    Doll, Richard; Peto, Richard; Boreham, Jillian; Sutherland, Isabelle

    2004-01-01

    Objective To compare the hazards of cigarette smoking in men who formed their habits at different periods, and the extent of the reduction in risk when cigarette smoking is stopped at different ages. Design Prospective study that has continued from 1951 to 2001. Setting United Kingdom. Participants 34 439 male British doctors. Information about their smoking habits was obtained in 1951, and periodically thereafter; cause specific mortality was monitored for 50 years. Main outcome measures Overall mortality by smoking habit, considering separately men born in different periods. Results The excess mortality associated with smoking chiefly involved vascular, neoplastic, and respiratory diseases that can be caused by smoking. Men born in 1900-1930 who smoked only cigarettes and continued smoking died on average about 10 years younger than lifelong non-smokers. Cessation at age 60, 50, 40, or 30 years gained, respectively, about 3, 6, 9, or 10 years of life expectancy. The excess mortality associated with cigarette smoking was less for men born in the 19th century and was greatest for men born in the 1920s. The cigarette smoker versus non-smoker probabilities of dying in middle age (35-69) were 42% ν 24% (a twofold death rate ratio) for those born in 1900-1909, but were 43% ν 15% (a threefold death rate ratio) for those born in the 1920s. At older ages, the cigarette smoker versus non-smoker probabilities of surviving from age 70 to 90 were 10% ν 12% at the death rates of the 1950s (that is, among men born around the 1870s) but were 7% ν 33% (again a threefold death rate ratio) at the death rates of the 1990s (that is, among men born around the 1910s). Conclusion A substantial progressive decrease in the mortality rates among non-smokers over the past half century (due to prevention and improved treatment of disease) has been wholly outweighed, among cigarette smokers, by a progressive increase in the smoker ν non-smoker death rate ratio due to earlier and more

  5. Southern Alpine floods of the last 50 years recorded in the sediment record from Lago Maggiore

    NASA Astrophysics Data System (ADS)

    Kämpf, L.; Brauer, A.; Guilizzoni, P.; Lami, A.

    2009-04-01

    The frequency of extreme floods is increasingly discussed under meteorological and anthropogenic forcing aspects because of their potentially disastrous consequences. Existing hydrological and meteorological instrumental data are, however, limited to rather short time scales. Records of natural geoarchives like lacustrine sediments, in contrast, reach much further back in time and reflect climate changes and environmental processes. In particular, extreme floods give an imprint to lake sediment records. The sediment loaded stream enters the lake water and eventually is deposited as a detrital layer. Here we present a multicore study from Pallanza Basin in the western part of Lago Maggiore. Major detrital layers are triggered mainly by flooding events of the Toce River. Through microfacies analyses of petrographic thin-sections and high-resolution element scanning techniques several detrital layers have been identified and correlated to historical flood events of the last 50 years. For this time interval fifteen flood event layers have been identified in the sediment record. Their thicknesses range from 0.5 to more than 15 mm. Noticeable is a rise of flooding events in the 1970s, which might be related to a change in atmospheric circulation patterns as documented in the NAO index. Comparison of these detrital layers in different cores allowed reconstructing their spatial distribution within the Pallanza Basin. Two detrital layers are clearly not related to regional floods but were generated by local slope failure or debris flows. This work is combined with studies of biological remains and pigment analyses, proving evidence of historical changes in the trophic state, pollution and climate history of the lake. Overall a comprehensive reconstruction of anthropogenic and climatic changes to Lake Maggiore for the last five decades is shown.

  6. Discovering the 50 Years of Solar System Exploration: Sharing Your Science with the Public

    NASA Astrophysics Data System (ADS)

    Buxner, Sanlyn; Dalton, H.; Shipp, S.; Shupla, C.; Halligan, E.; Boonstra, D.; Wessen, A.; Baerg, G.; Davis, P.; Burdick, A.; Zimmerman Brachman, R.

    2012-10-01

    The Year of the Solar System (YSS) offers ways for scientists to bring NASA’s science discoveries to their audiences! YSS and the continuing salute to the 50-year history of solar system exploration provide an integrated picture of our new understanding of the solar system for educators and the general public. During the last five decades, NASA has launched a variety of robotic spacecraft to study our solar system. Over that time, our understanding of planets has been revolutionized, as has the technology that has made these discoveries possible.Looking forward, the numerous ongoing and future robotic missions are returning new discoveries of our solar system at an unprecedented rate. YSS combines the discoveries of past NASA planetary missions with the most recent findings of the ongoing missions and connects them to related topics based on the big questions of planetary science, including solar system formation, volcanism, ice, and possible life elsewhere. Planetary scientists are encouraged to get involved in YSS in a variety of ways: - Give a talk at a local museum, planetarium, library, or school to share YSS and your research - Partner with a local educational institution to organize a night sky viewing or mission milestone community event - Work with a classroom teacher to explore one of the topics with students - Connect with a planetary science E/PO professional to identify ways to participate, like creating podcasts,vodcasts, or contributing to monthly topics - Share your ideas for events and activities with the planetaryE/PO community to identify partners and pathways for distribution - And more! Promotional and educational materials, updates, a calendar of activities, and a space to share experiences are available at NASA’s Solar System website: http://solarsystem.nasa.gov/yss. This is an exciting time in planetary sciences as we learn about New Worlds and make New Discoveries!

  7. Sequential Imaging of Earth by Astronauts: 50 Years of Global Change

    NASA Technical Reports Server (NTRS)

    Evans, Cynthia A.

    2009-01-01

    For nearly 50 years, astronauts have collected sequential imagery of the Earth. In fact, the collection of astronaut photography comprises one of the earliest sets of data (1961 to present) available to scientists to study the regional context of the Earth s surface and how it changes. While today s availability of global high resolution satellite imagery enables anyone with an internet connection to examine specific features on the Earth s surface with a regional context, historical satellite imagery adds another dimension (time) that provides researchers and students insight about the features and processes of a region. For example, one of the geographic areas with the longest length of record contained within the astronaut photography database is the lower Nile River. The database contains images that document the flooding of Lake Nasser (an analog to today s flooding behind China s Three Gorges Dam), the changing levels of Lake Nasser s water with multiyear cycles of flood and drought, the recent flooding and drying of the Toshka Lakes, as well as urban growth, changes in agriculture and coastal subsidence. The imagery database allows investigations using different time scales (hours to decades) and spatial scales (resolutions and fields of view) as variables. To continue the imagery collection, the astronauts on the International Space Station are trained to understand basic the Earth Sciences and look for and photograph major events such as tropical storms, landslides, and volcanic eruptions, and document landscapes undergoing change (e.g., coastal systems, cities, changing forest cover). We present examples of selected sequences of astronaut imagery that illustrate the interdependence of geological processes, climate cycles, human geography and development, and prompt additional questions about the underlying elements of change.

  8. The nature of species interactions shifts profoundly between time periods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species interactions change through time, for example ontogenetically, successionally, and evolutionarily. They also change as environmental conditions change, both within years (seasonally) and between years (year effects). The former are relatively well-studied, but the latter have received less a...

  9. Load Balancing Using Time Series Analysis for Soft Real Time Systems with Statistically Periodic Loads

    NASA Technical Reports Server (NTRS)

    Hailperin, Max

    1993-01-01

    This thesis provides design and analysis of techniques for global load balancing on ensemble architectures running soft-real-time object-oriented applications with statistically periodic loads. It focuses on estimating the instantaneous average load over all the processing elements. The major contribution is the use of explicit stochastic process models for both the loading and the averaging itself. These models are exploited via statistical time-series analysis and Bayesian inference to provide improved average load estimates, and thus to facilitate global load balancing. This thesis explains the distributed algorithms used and provides some optimality results. It also describes the algorithms' implementation and gives performance results from simulation. These results show that our techniques allow more accurate estimation of the global system load ing, resulting in fewer object migration than local methods. Our method is shown to provide superior performance, relative not only to static load-balancing schemes but also to many adaptive methods.

  10. 19 CFR 351.204 - Time periods and persons examined; voluntary respondents; exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 3 2011-04-01 2011-04-01 false Time periods and persons examined; voluntary... § 351.204 Time periods and persons examined; voluntary respondents; exclusions. (a) Introduction. Because the Act does not specify the precise period of time that the Secretary should examine in...

  11. 20 CFR 261.10 - Increase in future benefits where time period for reopening has expired.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Increase in future benefits where time period... where time period for reopening has expired. If, after the time period for reopening under § 261.2(b) of this part has expired, new evidence is furnished showing a different date of birth or new evidence...

  12. 12 CFR 390.102 - How does the FDIC compute time periods under this subpart?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 5 2014-01-01 2014-01-01 false How does the FDIC compute time periods under... Application Processing Procedures § 390.102 How does the FDIC compute time periods under this subpart? In computing time periods under this subpart, the FDIC does not include the day of the act or event...

  13. 12 CFR 390.102 - How does the FDIC compute time periods under this subpart?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false How does the FDIC compute time periods under... Application Processing Procedures § 390.102 How does the FDIC compute time periods under this subpart? In computing time periods under this subpart, the FDIC does not include the day of the act or event...

  14. 12 CFR 116.10 - How does the OCC compute time periods under this part?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false How does the OCC compute time periods under... TREASURY APPLICATION PROCESSING PROCEDURES § 116.10 How does the OCC compute time periods under this part? In computing time periods under this part, the OCC does not include the day of the act or event...

  15. 12 CFR 116.10 - How does the OCC compute time periods under this part?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 1 2014-01-01 2014-01-01 false How does the OCC compute time periods under... TREASURY APPLICATION PROCESSING PROCEDURES § 116.10 How does the OCC compute time periods under this part? In computing time periods under this part, the OCC does not include the day of the act or event...

  16. 12 CFR 390.102 - How does the FDIC compute time periods under this subpart?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 5 2012-01-01 2012-01-01 false How does the FDIC compute time periods under... Application Processing Procedures § 390.102 How does the FDIC compute time periods under this subpart? In computing time periods under this subpart, the FDIC does not include the day of the act or event...

  17. 12 CFR 116.10 - How does the OCC compute time periods under this part?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 1 2013-01-01 2013-01-01 false How does the OCC compute time periods under... TREASURY APPLICATION PROCESSING PROCEDURES § 116.10 How does the OCC compute time periods under this part? In computing time periods under this part, the OCC does not include the day of the act or event...

  18. Estimation of Maximum Likelihood of the Unextendable Dead Time Period in a Flow of Physical Events

    NASA Astrophysics Data System (ADS)

    Gortsev, A. M.; Solov'ev, A. A.

    2016-03-01

    A flow of physical events (photons, electrons, etc.) is studied. One of the mathematical models of such flows is the MAP-flow of events. The flow circulates under conditions of the unextendable dead time period, when the dead time period is unknown. The dead time period is estimated by the method of maximum likelihood from observations of arrival instants of events.

  19. Significant warming of continental West Antarctica in the last 50 years

    NASA Astrophysics Data System (ADS)

    Steig, E. J.; Schneider, D. P.

    2008-12-01

    We use statistical climate field reconstruction techniques to determine monthly temperature anomalies for the near-surface of the Antarctic ice sheet since 1957. Two independent data sets are used to provide estimates of the spatial covariance patterns of temperature: automatic weather stations and thermal infrared satellite observations. Quality-controlled data from occupied instrumental weather stations are used to determine the amplitude of changes in those covariance patterns through time. We use a modified principal component analyses technique (Steig et al., in review, Nature) to optimize the combination of spatial and temporal information. Verification statistics obtained from subsets of the data demonstrate the resulting reconstructions represent improvements relative to climatological mean values. We find that significant warming has occurred over most of continental West Antarctica. This is an area much larger than previously reported; most studies have concluded that warming is limited to the Antarctic Peninsula. An updated version of the recent temperature reconstruction of Monaghan et al. (2008, JGR) independently confirms our results. Warming in continental West Antarctica in the last 50 years exceeds 0.1 °C/decade, and is strongest in Spring. A possible explanation is an increase in storms in the Amundsen-Bellinghausen sea, resulting in enhanced warm air fluxes to the continent. Increased storminess in this sector is associated with the positive phase of the zonal wave-3 pattern, which independent observations suggest has increased since the 1970s (Raphael, GRL, 2004). The substantial negative sea ice anomalies in the Amundsen-Bellinghausen sea may also play a role. Our results suggest that changes in the wave-3 pattern dominates over (possibly anthropogenic) changes in the Southern Annular Mode in explaining recent Antarctic temperature variability.

  20. The integration of science and politics to clean up 50 years in the nuclear sandbox

    SciTech Connect

    Lyons, C.E.; Holeman, T.

    1999-07-01

    The Cold War was fought between world superpowers for approximately 40 years from the end of the second World War until the end of the 1980s. During that time, the US government devoted billions of dollars to the development and production of nuclear weapons. Now the Cold War is over and the US is left with numerous nuclear weapons factories, stockpiles of nuclear materials, and mountains of waste to decontaminate and decommission. In the heat of the Cold War, little or no thought was given to how the facilities building bombs would be dismantled. Far too little attention was paid to the potential human health and environmental impact of the weapons production. Now, dozens of communities across the country face the problems this negligence created. In many cases, the location, extent, and characteristics of the waste and contamination are unknown, due to negligence or due to intentional hiding of waste and associated problems. Water supplies are contaminated and threatened; air quality is degraded and threatened; workers and residents risk contamination and health impacts; entire communities risk disaster from potential nuclear catastrophe. The US government, in the form of the US Department of Energy (DOE), now accepts responsibility for creating and cleaning up the mess. But it is the local communities, the home towns of the bomb factories and laboratories, that carry a significant share of the burden of inventing the science and politics required to clean up 50 years in the nuclear sandbox. The purpose of this paper is to evaluate the role of the local community in addressing the cleanup of the US nuclear weapons complex. Local governments do not own nor are responsible for the environmental aftermath, but remain the perpetual neighbor to the facility, the hometown of workers, and long-term caretaker of the off-site impacts of the on-site contamination and health risks.

  1. Celebrating 50 Years of Reflective Practice: Versions of Creative Problem Solving

    ERIC Educational Resources Information Center

    Isaksen, Scott G.; Treffinger, Donald J.

    2004-01-01

    The original work of Alex Osborn making the creative process more explicit, and the following 50 years of research and development on creative problem solving, have made an important and wide-spread contribution to those interested in the deliberate development of creative talent. This article provided a summary of the many versions of creative…

  2. The "Global" Formulation of Thermodynamics and the First Law: 50 Years On

    ERIC Educational Resources Information Center

    Gislason, Eric A.; Craig, Norman C.

    2011-01-01

    Nearly 50 years ago, Henry Bent published his groundbreaking article in this "Journal" introducing the "global" formulation of thermodynamics. In the following years, the global formulation was elaborated by Bent and by one of the present authors. The global formulation of the first law focuses on conservation of energy and the recognition that…

  3. The School Health Education Study + 50 Years: Scholars' Reflections on Its Impact and Legacy

    ERIC Educational Resources Information Center

    McDermott, Robert J.; Mayer, Alyssa B.

    2011-01-01

    Background: Launched 50 years ago, the School Health Education Study (SHES) examined the health education offerings in 135 public school systems, in 38 states, and over 1100 elementary schools and 350 secondary schools. In its second year, knowledge surveys were administered to students in grades 6, 9 and 12 at many of these schools. Analysis of…

  4. 1958-2008: 50 Years of Youth Fitness Tests in the United States

    ERIC Educational Resources Information Center

    Morrow, James R., Jr.; Zhu, Weimo; Franks, B. Don; Meredith, Marilu D.; Spain, Christine

    2009-01-01

    The AAHPER Youth Fitness Test, the first U.S. national fitness test, was published 50 years ago. The seminal work of Krause and Hirschland influenced the fitness world and continues to do so today. Important youth fitness test initiatives in the last half century are summarized. Key elements leading to continued interest in youth fitness testing…

  5. Keeping on Keeping on: OCR and Complaints of Racial Discrimination 50 Years after "Brown"

    ERIC Educational Resources Information Center

    Pollock, Mica

    2005-01-01

    This article, written by a former civil rights investigator in the U.S. Department of Education's Office for Civil Rights (OCR), contends that ordinary Americans advocating for equal educational opportunity for students of color might enlist OCR more actively and knowingly to help secure racial equality of opportunity 50 years after "Brown." Now a…

  6. Comprehension of a Colon Cancer Pamphlet among American Adults at Least 50 Years of Age

    ERIC Educational Resources Information Center

    Liu, Chiung-ju

    2010-01-01

    Objective: The purpose of this study was to identify determinants of comprehension of an educational pamphlet on colon cancer, by adults at least 50 years of age living in the United States. Design: Data were analysed from the "2003 National Assessment of Adult Literacy" survey. The survey was designed to assess functional English literacy, which…

  7. Male and Female Photographic Representation in 50 Years of "Music Educators Journal"

    ERIC Educational Resources Information Center

    Kruse, Adam J.; Giebelhausen, Robin; Shouldice, Heather N.; Ramsey, Andrea L.

    2015-01-01

    Considering the potential for stereotypes to shape professional expectations, the four researchers in this study investigated photographic representation of adult men and women in implied positions of authority in 50 years (1962-2011) of issues of "Music Educators Journal" ("MEJ"). Data included every photograph (N = 7,288) of…

  8. Controlling mixing and segregation in time periodic granular flows

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Tathagata

    Segregation is a major problem for many solids processing industries. Differences in particle size or density can lead to flow-induced segregation. In the present work, we employ the discrete element method (DEM)---one type of particle dynamics (PD) technique---to investigate the mixing and segregation of granular material in some prototypical solid handling devices, such as a rotating drum and chute. In DEM, one calculates the trajectories of individual particles based on Newton's laws of motion by employing suitable contact force models and a collision detection algorithm. Recently, it has been suggested that segregation in particle mixers can be thwarted if the particle flow is inverted at a rate above a critical forcing frequency. Further, it has been hypothesized that, for a rotating drum, the effectiveness of this technique can be linked to the probability distribution of the number of times a particle passes through the flowing layer per rotation of the drum. In the first portion of this work, various configurations of solid mixers are numerically and experimentally studied to investigate the conditions for improved mixing in light of these hypotheses. Besides rotating drums, many studies of granular flow have focused on gravity driven chute flows owing to its practical importance in granular transportation and to the fact that the relative simplicity of this type of flow allows for development and testing of new theories. In this part of the work, we observe the deposition behavior of both mono-sized and polydisperse dry granular materials in an inclined chute flow. The effects of different parameters such as chute angle, particle size, falling height and charge amount on the mass fraction distribution of granular materials after deposition are investigated. The simulation results obtained using DEM are compared with the experimental findings and a high degree of agreement is observed. Tuning of the underlying contact force parameters allows the achievement

  9. Taylor dispersion in the presence of time-periodic convection phenomena. Part I. Local-space periodicity

    NASA Astrophysics Data System (ADS)

    Shapiro, M.; Brenner, H.

    1990-10-01

    Generalized Taylor dispersion theory is herein extended to circumstances for which the transport of dissolved or suspended chemically reactive (as well as inert) solutes is affected by carrier-solvent flow fields and/or external forces that are time periodic in both their global and local microscale spaces (and possess commensurate frequencies). The local-space- and time-averaged solute transport process is characterized by three time-independent, but frequency-dependent microscale phenomenological coefficients—K¯*, Ū*, and cf6D*, representing the mean chemical reaction rate, velocity vector, and dispersivity dyadic of the solute, respectively. These macroscale transport coefficients are expressed in terms of time-periodic eigenfunctions and corresponding eigenvalues using a recently developed solution scheme. This scheme permits the analysis of phenomena involving time-periodic transport coefficients on a par with that for the classical case of time-independent microscale phenomenological coefficients. The analysis generalizes to time-periodic local-space phenomena a previous treatment, in which only the global-space coefficients were allowed to vary periodically with time. This greatly enlarges the scope of potential applications of the analysis. In addition to the time-averaged phenomenological coefficients K¯*, Ū*, and CF6D*, comparable instantaneous coefficients are defined governing the local-space-averaged instantaneous solute concentration. In contrast with their time-averaged counterparts, K¯*, Ū*, and CF6D*, the latter instantaneous transport coefficients are shown to depend upon the initial solute distribution within the local space. Because of coupling between the local- and global-space transport processes in oscillatory flows and/or oscillatory external force fields, all harmonics of the resulting global-space solute velocity field contribute to the mean convective solute transport. This phenomenon may result, for example, in zero solvent

  10. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Duty period limitations and rest time requirements. 135.273 Section 135.273 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Crewmember Flight Time and Duty Period Limitations and Rest Requirements § 135.273 Duty period...

  11. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Duty period limitations and rest time requirements. 135.273 Section 135.273 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Crewmember Flight Time and Duty Period Limitations and Rest Requirements § 135.273 Duty period...

  12. CD4 count at presentation for HIV care in the United States and Canada: Are those over 50 years more likely to have a delayed presentation?

    PubMed Central

    2010-01-01

    We assessed CD4 count at initial presentation for HIV care among ≥50-year-olds from 1997-2007 in 13 US and Canadian clinical cohorts and compared to <50-year-olds. 44,491 HIV-infected individuals in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) were included in our study. Trends in mean CD4 count (measured as cells/mm3) and 95% confidence intervals ([,]) were determined using linear regression stratified by age category and adjusted for gender, race/ethnicity, HIV transmission risk and cohort. From 1997-2007, the proportion of individuals presenting for HIV care who were ≥50-years-old increased from 17% to 27% (p-value < 0.01). The median CD4 count among ≥50 year-olds was consistently lower than younger adults. The interaction of age group and calendar year was significant (p-value <0.01) with both age groups experiencing modest annual improvements over time (< 50-year-olds: 5 [4 , 6] cells/mm3; ≥50-year-olds: 7 [5 , 9] cells/mm3), after adjusting for sex, race/ethnicity, HIV transmission risk group and cohort; however, increases in the two groups were similar after 2000. A greater proportion of older individuals had an AIDS-defining diagnosis at, or within three months prior to, first presentation for HIV care compared to younger individuals (13% vs. 10%, respectively). Due to the increasing proportion, consistently lower CD4 counts, and more advanced HIV disease in adults ≥50-year-old at first presentation for HIV care, renewed HIV testing efforts are needed. PMID:21159161

  13. A post audit and inverse modeling in reactive transport: 50 years of artificial recharge in the Amsterdam Water Supply Dunes

    NASA Astrophysics Data System (ADS)

    Karlsen, R. H.; Smits, F. J. C.; Stuyfzand, P. J.; Olsthoorn, T. N.; van Breukelen, B. M.

    2012-08-01

    SummaryThis article describes the post audit and inverse modeling of a 1-D forward reactive transport model. The model simulates the changes in water quality following artificial recharge of pre-treated water from the river Rhine in the Amsterdam Water Supply Dunes using the PHREEQC-2 numerical code. One observation dataset is used for model calibration, and another dataset for validation of model predictions. The total simulation time of the model is 50 years, from 1957 to 2007, with recharge composition varying on a monthly basis and the post audit is performed 26 years after the former model simulation period. The post audit revealed that the original model could reasonably predict conservative transport and kinetic redox reactions (oxygen and nitrate reduction coupled to the oxidation of soil organic carbon), but showed discrepancies in the simulation of cation exchange. Conceptualizations of the former model were inadequate to accurately simulate water quality changes controlled by cation exchange, especially concerning the breakthrough of potassium and magnesium fronts. Changes in conceptualization and model design, including the addition of five flow paths, to a total of six, and the use of parameter estimation software (PEST), resulted in a better model to measurement fit and system representation. No unique parameter set could be found for the model, primarily due to high parameter correlations, and an assessment of the predictive error was made using a calibration constrained Monte-Carlo method, and evaluated against field observations. The predictive error was found to be low for Na+ and Ca2+, except for greater travel times, while the K+ and Mg2+ error was restricted to the exchange fronts at some of the flow paths. Optimized cation exchange coefficients were relatively high, especially for potassium, but still within the observed range in literature. The exchange coefficient for potassium agrees with strong fixation on illite, a main clay mineral in

  14. Load Balancing Using Time Series Analysis for Soft Real Time Systems with Statistically Periodic Loads

    NASA Technical Reports Server (NTRS)

    Hailperin, M.

    1993-01-01

    This thesis provides design and analysis of techniques for global load balancing on ensemble architectures running soft-real-time object-oriented applications with statistically periodic loads. It focuses on estimating the instantaneous average load over all the processing elements. The major contribution is the use of explicit stochastic process models for both the loading and the averaging itself. These models are exploited via statistical time-series analysis and Bayesian inference to provide improved average load estimates, and thus to facilitate global load balancing. This thesis explains the distributed algorithms used and provides some optimality results. It also describes the algorithms' implementation and gives performance results from simulation. These results show that the authors' techniques allow more accurate estimation of the global system loading, resulting in fewer object migrations than local methods. The authors' method is shown to provide superior performance, relative not only to static load-balancing schemes but also to many adaptive load-balancing methods. Results from a preliminary analysis of another system and from simulation with a synthetic load provide some evidence of more general applicability.

  15. Optical Sciences Center/College of Optical Sciences: 50 years of excellence

    NASA Astrophysics Data System (ADS)

    Wyant, James C.

    2014-09-01

    Aden B. Meinel established the University of Arizona Optical Sciences Center, now known as the College of Optical Sciences, in 1964 to fulfill a national need for more highly trained engineers and physicists in the optical sciences. Throughout its 50-year history, OSC has grown and evolved in response to industrial demand. It now includes a worldclass faculty and an international student body, and its academic programs offer more than 100 graduate and undergraduate courses, an ABET-accredited undergraduate optical sciences and engineering degree program, and outstanding M.S. and Ph.D. graduate programs with extensive distance learning options. Its graduates are in great demand and are employed by national and international governments, businesses and universities. This paper will describe the formation of OSC and its 50 years of excellence.

  16. Space optics contributions by the College of Optical Sciences over the past 50 years

    NASA Astrophysics Data System (ADS)

    Breckinridge, James B.; Smith, Peter

    2014-10-01

    We present a review of the contributions by students, staff, faculty and alumni to the Nation's space program over the past 50 years. The balloon polariscope led the way to future space optics missions. The missions Pioneer Venus (large probe solar flux radiometer), Pioneer 10/11 (imaging photopolarimeter) to Jupiter and Saturn, Hubble Space Telescope (HST), and next generation large aperture space telescopes are discussed.

  17. 20 CFR 404.996 - Increase in future benefits where time period for reopening expires.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Increase in future benefits where time period for reopening expires. 404.996 Section 404.996 Employees' Benefits SOCIAL SECURITY ADMINISTRATION... § 404.996 Increase in future benefits where time period for reopening expires. If, after the time...

  18. 20 CFR 404.996 - Increase in future benefits where time period for reopening expires.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Increase in future benefits where time period for reopening expires. 404.996 Section 404.996 Employees' Benefits SOCIAL SECURITY ADMINISTRATION... § 404.996 Increase in future benefits where time period for reopening expires. If, after the time...

  19. 20 CFR 404.996 - Increase in future benefits where time period for reopening expires.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Increase in future benefits where time period for reopening expires. 404.996 Section 404.996 Employees' Benefits SOCIAL SECURITY ADMINISTRATION... § 404.996 Increase in future benefits where time period for reopening expires. If, after the time...

  20. 20 CFR 404.996 - Increase in future benefits where time period for reopening expires.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Increase in future benefits where time period for reopening expires. 404.996 Section 404.996 Employees' Benefits SOCIAL SECURITY ADMINISTRATION... § 404.996 Increase in future benefits where time period for reopening expires. If, after the time...

  1. The distributions of Chinese yak breeds in response to climate change over the past 50 years.

    PubMed

    Wu, Jianguo

    2016-07-01

    The effects of prior climate change on yak breed distributions are uncertain. Here, we measured changes in the distributions of 12 yak breeds over the past 50 years in China and examined whether the changes could be attributed to climate change. Long-term records of yak breed distribution, grey relational analysis, fuzzy sets classification techniques and attribution methods were used. Over the past 50 years, the distributions of several yak breeds have changed in multiple directions, mainly shifting northward or westward, and most of these changes are related to the thermal index. Driven by climate change over the past years, the suitable range and the distribution centers of certain yak breeds have changed with fluctuation and have mainly shifted northward, eastward or southward. The consistency of observed versus predicted changes in distribution boundaries or distribution centers is higher for certain yak breeds. Changes in the eastern distribution boundary of two yak breeds over the past 50 years can be attributed to climate change. PMID:26470629

  2. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... time, using Coordinated Universal Time or local time, that begins at midnight and ends 24 hours later... calculated using either Coordinated Universal Time or local time to reflect the total elapsed time. Flight... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Duty period limitations and rest...

  3. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... time, using Coordinated Universal Time or local time, that begins at midnight and ends 24 hours later... calculated using either Coordinated Universal Time or local time to reflect the total elapsed time. Flight... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Duty period limitations and rest...

  4. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... time, using Coordinated Universal Time or local time, that begins at midnight and ends 24 hours later... calculated using either Coordinated Universal Time or local time to reflect the total elapsed time. Flight... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Duty period limitations and rest...

  5. [The historical aspect: the first 10 years of the Danish Medicines Agency--and the 50 years that came before].

    PubMed

    Overø, Jens

    2008-01-01

    In 1997, the office for administration regarding medicines and pharmacies was separated from the Danish Board of Health and organised as the Danish Medicines Agency (Laegemiddelstyrelsen). This Agency celebrated its 10 years anniversary by publishing a book, "Staten og laegemidlerne" (The state and the medicines), describing various aspects of the official control of medicines. The book chapters focus mainly on the latest 25-50 years, because the earlier periods from the 16th century and onwards have been thoroughly described previously, whereas more recent developments are more sparsely discussed in the literature. The present article emphasises the importance of keeping knowledge of the historical development alive. Many aspects of present day regulation only make sense with knowledge of what came before. PMID:18548943

  6. 19 CFR 351.204 - Time periods and persons examined; voluntary respondents; exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... § 351.204 Time periods and persons examined; voluntary respondents; exclusions. (a) Introduction... fiscal quarters (or, in an investigation involving merchandise imported from a nonmarket economy...

  7. Structure and dating errors in the geologic time scale and periodicity in mass extinctions

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.

    1989-01-01

    Structure in the geologic time scale reflects a partly paleontological origin. As a result, ages of Cenozoic and Mesozoic stage boundaries exhibit a weak 28-Myr periodicity that is similar to the strong 26-Myr periodicity detected in mass extinctions of marine life by Raup and Sepkoski. Radiometric dating errors in the geologic time scale, to which the mass extinctions are stratigraphically tied, do not necessarily lessen the likelihood of a significant periodicity in mass extinctions, but do spread the acceptable values of the period over the range 25-27 Myr for the Harland et al. time scale or 25-30 Myr for the DNAG time scale. If the Odin time scale is adopted, acceptable periods fall between 24 and 33 Myr, but are not robust against dating errors. Some indirect evidence from independently-dated flood-basalt volcanic horizons tends to favor the Odin time scale.

  8. Dynamics of phase slips in systems with time-periodic modulation

    NASA Astrophysics Data System (ADS)

    Gandhi, Punit; Knobloch, Edgar; Beaume, Cédric

    2015-12-01

    The Adler equation with time-periodic frequency modulation is studied. A series of resonances between the period of the frequency modulation and the time scale for the generation of a phase slip is identified. The resulting parameter space structure is determined using a combination of numerical continuation, time simulations, and asymptotic methods. Regions with an integer number of phase slips per period are separated by regions with noninteger numbers of phase slips and include canard trajectories that drift along unstable equilibria. Both high- and low-frequency modulation is considered. An adiabatic description of the low-frequency modulation regime is found to be accurate over a large range of modulation periods.

  9. 17 CFR 260.7a-24 - Words relating to periods of time in the past.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Words relating to periods of time in the past. 260.7a-24 Section 260.7a-24 Commodity and Securities Exchanges SECURITIES AND... Requirements As to Contents § 260.7a-24 Words relating to periods of time in the past. Unless the...

  10. 17 CFR 260.7a-24 - Words relating to periods of time in the past.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Words relating to periods of time in the past. 260.7a-24 Section 260.7a-24 Commodity and Securities Exchanges SECURITIES AND... Requirements As to Contents § 260.7a-24 Words relating to periods of time in the past. Unless the...

  11. 47 CFR 54.724 - Time periods for Commission approval of Administrator decisions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Time periods for Commission approval of...) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Review of Decisions Issued by the Administrator § 54.724 Time periods for Commission approval of Administrator decisions. (a) The Wireline...

  12. 47 CFR 54.724 - Time periods for Commission approval of Administrator decisions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Time periods for Commission approval of...) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Review of Decisions Issued by the Administrator § 54.724 Time periods for Commission approval of Administrator decisions. (a) The Wireline...

  13. 47 CFR 54.724 - Time periods for Commission approval of Administrator decisions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Time periods for Commission approval of...) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Review of Decisions Issued by the Administrator § 54.724 Time periods for Commission approval of Administrator decisions. (a) The Wireline...

  14. 47 CFR 54.724 - Time periods for Commission approval of Administrator decisions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Time periods for Commission approval of Administrator decisions. 54.724 Section 54.724 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Review of Decisions Issued by the Administrator § 54.724 Time periods for...

  15. 47 CFR 54.724 - Time periods for Commission approval of Administrator decisions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Time periods for Commission approval of...) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Review of Decisions Issued by the Administrator § 54.724 Time periods for Commission approval of Administrator decisions. (a) The Wireline...

  16. 12 CFR 516.10 - How does OTS compute time periods under this part?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 5 2011-01-01 2011-01-01 false How does OTS compute time periods under this part? 516.10 Section 516.10 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY APPLICATION PROCESSING PROCEDURES § 516.10 How does OTS compute time periods under this part? In...

  17. 12 CFR 516.10 - How does OTS compute time periods under this part?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false How does OTS compute time periods under this part? 516.10 Section 516.10 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY APPLICATION PROCESSING PROCEDURES § 516.10 How does OTS compute time periods under this part? In...

  18. 12 CFR 516.10 - How does OTS compute time periods under this part?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 6 2013-01-01 2012-01-01 true How does OTS compute time periods under this part? 516.10 Section 516.10 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY APPLICATION PROCESSING PROCEDURES § 516.10 How does OTS compute time periods under this part? In...

  19. 12 CFR 516.10 - How does OTS compute time periods under this part?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 6 2014-01-01 2012-01-01 true How does OTS compute time periods under this part? 516.10 Section 516.10 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY APPLICATION PROCESSING PROCEDURES § 516.10 How does OTS compute time periods under this part? In...

  20. 12 CFR 516.10 - How does OTS compute time periods under this part?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 6 2012-01-01 2012-01-01 false How does OTS compute time periods under this part? 516.10 Section 516.10 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY APPLICATION PROCESSING PROCEDURES § 516.10 How does OTS compute time periods under this part? In...

  1. 17 CFR 260.7a-24 - Words relating to periods of time in the past.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Words relating to periods of time in the past. 260.7a-24 Section 260.7a-24 Commodity and Securities Exchanges SECURITIES AND... Requirements As to Contents § 260.7a-24 Words relating to periods of time in the past. Unless the...

  2. 17 CFR 260.7a-24 - Words relating to periods of time in the past.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Words relating to periods of time in the past. 260.7a-24 Section 260.7a-24 Commodity and Securities Exchanges SECURITIES AND... Requirements As to Contents § 260.7a-24 Words relating to periods of time in the past. Unless the...

  3. 26 CFR 1.676(b)-1 - Powers exercisable only after a period of time.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Powers exercisable only after a period of time...)-1 Powers exercisable only after a period of time. Section 676(b) provides an exception to the general rule of section 676(a) when the exercise of a power can only affect the beneficial enjoyment...

  4. Formation of the 50-Year Element 94 from Deuteron Bombardment of U{sup 238}

    DOE R&D Accomplishments Database

    Kennedy, J. W.; Perlman, M. L.; Segre, E.; Wahl, A. C.

    1942-06-01

    It has been shown by bombardment with deuterons of a sample of U{sup 238}, greatly depleted in U{sup 235} and U{sup 234}, that the 50-year 94 activity and 2.0 day 93 activity are formed in approximately the same yield as with the natural mixture of uranium isotopes. The activities are thus shown to arise from the U{sup 238} nucleus, and from considerations of the energy of the compound nucleus (U{sup 238} + d).

  5. Rapid eye movement sleep behavior disorder in adults younger than 50 years of age.

    PubMed

    Ju, Yo-El S

    2013-08-01

    Rapid eye movement (REM) sleep behavior disorder (RBD) occurring prior to age 50 is termed early-onset RBD. Early-onset RBD comprises a substantial minority of cases, and demonstrates the differences in demographics, comorbidities, and clinical considerations from previously described typical RBD with onset >50years. The world literature on RBD is reviewed with specific focus on features that distinguish early-onset RBD, including more gender parity, increased proportion of idiopathic cases, increased proportion of cases associated with narcolepsy, parasomnia overlap disorder, antidepressants, and possibly autoimmune disorders, and clinical presentation. PMID:23347910

  6. 50 years of helium liquefaction at the MIT Cryogenic Engineering Laboratory

    NASA Astrophysics Data System (ADS)

    Smith, Joseph L.

    2002-05-01

    The evolution of the helium liquefaction facility of the MIT Cryogenic Engineering Laboratory and the history of its operation over the last 50 years are described. Professor Samuel C. Collins created the liquid-helium facility based on his earlier developments. The chronology of the laboratory helium liquefiers is given with a brief description of each one. The current facility based on the Model 2000 liquefier is described and operating experience is given. The reasons for the very high availability of the liquefaction system are developed.

  7. Heel pain due to psoriatic arthritis in a 50 year old recreational male athlete: case report

    PubMed Central

    Yedon, Dominique Forand; Howitt, Scott

    2011-01-01

    Heel pain is a common presentation in a sports injury practice, with a list of common differentials including achilles tendinopathy and retrocalcaneal bursitis. However, seronegative arthritis can also cause enthesopathies that produce heel pain and should be considered in a differential diagnosis list. In this case, a 50 year old recreationally active male presented with non-traumatic insidious heel pain and without history of any skin conditions or any other symptoms of seronegative spondyloarthritis. Clinical suspicion led to laboratory testing and radiographs/bone scan which yielded the diagnosis of psoriatic arthritis. PMID:22131565

  8. A Perspective on the Intended Science Curriculum in Iceland and Its "Transformation" over a Period of 50 Years

    ERIC Educational Resources Information Center

    Thorolfsson, Meyvant; Finnbogason, Gunnar E.; Macdonald, Allyson

    2012-01-01

    In recent decades, a consensus has emerged among educators and scientists that all compulsory school students need good science education. The debate about its purpose and nature as a school subject in an emerging information society has not been as conclusive. To further understand this, it helps to examine how the science curriculum has…

  9. Predicting fire activity in the US over the next 50 years using new IPCC climate projections

    NASA Astrophysics Data System (ADS)

    Wang, D.; Morton, D. C.; Collatz, G. J.

    2012-12-01

    Fire is an integral part of the Earth system with both direct and indirect effects on terrestrial ecosystems, the atmosphere, and human societies (Bowman et al. 2009). Climate conditions regulate fire activities through a variety of ways, e.g., influencing the conditions for ignition and fire spread, changing vegetation growth and decay and thus the accumulation of fuels for combustion (Arora and Boer 2005). Our recent study disclosed the burned area (BA) in US is strongly correlated with potential evaporation (PE), a measurement of climatic dryness derived from National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR) climate data (Morton et al. 2012). The correlation varies spatially and temporally. With regard to fire of peak fire seasons, Northwestern US, Great Plains and Alaska have the strongest BA/PE relationship. Using the recently released the Global Fire Emissions Database (GFED) Version 3 (van der Werf et al. 2010), we showed increasing BA in the last decade in most of NCA regions. Longer time series of Monitoring Trends in Burn Severity (MTBS) (Eidenshink et al. 2007) data showed the increasing trends occurred in all NCA regions from 1984 to 2010. This relationship between BA and PE provides us the basis to predict the future fire activities in the projected climate conditions. In this study, we build spatially explicit predictors using the historic PE/BA relationship. PE from 2011 to 2060 is calculated from the Coupled Model Intercomparison Project Phase 5 (CMIP5) data and the historic PE/BA relationship is then used to estimate BA. This study examines the spatial pattern and temporal dynamics of the future US fires driven by new climate predictions for the next 50 years. Reference: Arora, V.K., & Boer, G.J. (2005). Fire as an interactive component of dynamic vegetation models. Journal of Geophysical Research-Biogeosciences, 110 Bowman, D.M.J.S., Balch, J.K., Artaxo, P., Bond, W.J., Carlson, J.M., Cochrane, M.A., D

  10. PREFACE: 50 years in science: Alejandro Szanto de Toledo (2045-2015)

    NASA Astrophysics Data System (ADS)

    2015-07-01

    During the XXXVII RTFNB 2014, we had the pleasure to organize a tribute to Professor Alejandro Szanto de Toledo to commemorate his 50 years of dedication to nuclear physics. Named ''Alexfest'', it gathered friends and very prominent physicists from around the world that came to Brazil specially to render a tribute to Alex, as many friends and colleagues called him. During the whole afternoon, the invited speakers presented some of the physics topics and important contributions that Alex gave to the field of nuclear physics during his five decades of intense work. Alex is the responsible for several landmarks in the Brazilian nuclear science, especially in the Institute of Physics of the University of Sao Paulo (IFUSP), where he spent almost his entire career. He started his professional life in the IFUSP Van de Graaf Laboratory, under Oscar Sala's supervision as an undergraduate student. His talent allowed him to give significant contributions to the machine operation since the beginning of his internship in the laboratory. He soon became the responsible for the development, construction and implementation of an ion source for the new Pelletron accelerator, project coordinated by Oscar Sala as well. This was a huge responsibility for a young master degree student. His PhD thesis was about nuclear fusion, a topic that he mastered during his career. His international reputation allowed him to become a visiting researcher at several laboratories in the US, France, Japan, Russia and Germany. Not satisfied with the challenges that his career was imposing to him, Alex pioneered the creation of a high-energy nuclear physics group in Brazil, becoming member of the STAR (Solenoidal Tracker At Rhic) collaboration in 1995, one of the two major experiments of the RHIC accelerator (Relativistic heavy Ion Collider), located in the Brookhaven National Laboratory, USA. Later on, in 2006, he also led his group to become part of the LHC (Large Hadron Collider) experiment ALICE (A

  11. [Progress in and outcomes of neonatal surgery over the past 50 years].

    PubMed

    Taguchi, Tomoaki; Nagata, Kouji; Kinoshita, Yoshiaki; Esumi, Genshiro

    2014-11-01

    The Japanese Society of Pediatric Surgeons has performed a nationwide survey of neonatal surgery every 5 years during the 50 years since its foundation. The number of neonatal surgical cases has increased 5-fold during those 50 years, while the mortality rate has decreased from 60% to 15% for the main life-threatening diseases (such as esophageal atresia, diaphragmatic hernia, omphalocele, and gastroschisis). Currently, most neonatal patients who undergo surgery for severe cardiac or chromosomal anomalies survive. Therefore, pediatric surgeons are aware of the need for cosmetic considerations. Endoscopic surgical procedures and incisions using natural skin creases have been developed to achieve good cosmetic results and improve patients' quality of life. On the other hand, severe life-threatening neonatal surgical cases are still seen, such as patients with diaphragmatic hernia accompanied by severe pulmonary hypoplasia, huge sacrococcygeal teratomas, and neonatal intestinal perforation. Fetal intervention or early delivery should be considered to improve survival. Appropriate initial treatment strategies for intestinal perforation in very low birth-weight infants are needed. PMID:25702509

  12. Dietary patterns and risk of hip fractures in postmenopausal women and men over 50 years

    PubMed Central

    Fung, Teresa T.; Feskanich, Diane

    2016-01-01

    Purpose We examined the association between predominant dietary patterns and risk of hip fractures in postmenopausal women and men over 50 years. Methods We used data from 74,540 women in the Nurses’ Health Study followed between 1980 and 2010, and 35,451 men from the Health Professionals Follow-up Study followed between 1986 and 2012 for this analysis. Health and lifestyle information was assessed every two years. Diet was assessed approximately every four years with a food frequency questionnaire. Two major dietary patterns were previously derived using principal component analysis. The Prudent pattern is characterized by higher intakes of fruits, vegetables, whole grains, and poultry, and the Western pattern is characterized by higher intakes of red and processed meats, sweets, and refined grains. We computed relative risks (RR) for hip fracture by dietary pattern scores using Cox proportional hazards models, adjusting for potential confounders. Results During follow-up, there were 1891 hip fractures in women and 596 in men. No association was observed between the Prudent or Western pattern and risk of hip fractures in either men or women. We also did not find an association among lean (BMI<25) or overweight (BMI >=25) individuals or among those with higher or lower levels of physical activity. Conclusion Neither the Prudent nor the Western dietary pattern was associated with risk of hip fractures in postmenopausal women or men over 50 years of age. PMID:25731807

  13. Influence of allowable interruption period on estimates of accelerometer wear time and sedentary time in older adults

    PubMed Central

    Mailey, Emily L.; Gothe, Neha P.; Wójcicki, Thomas R.; Szabo, Amanda N.; Olson, Erin A.; Mullen, Sean P.; Fanning, Jason T.; Motl, Robert W.; McAuley, Edward

    2013-01-01

    The criteria one uses to reduce accelerometer data can profoundly influence the interpretation of research outcomes. The purpose of this study was to examine the influence of three different interruption periods (i.e., 20, 30, and 60 minutes) on the amount of data retained for analyses and estimates of sedentary time among older adults. Older adults (N=311; Mage=71.1) wore an accelerometer for seven days and reported wear time on an accelerometer log. Accelerometer data were downloaded and scored using 20, 30, and 60-minute interruption periods. Estimates of wear time derived using each interruption period were compared to self-reported wear time, and descriptive statistics were used to compare estimates of sedentary time. Results showed a longer interruption period (i.e., 60 minutes) yields the largest sample size and the closest approximation of self-reported wear time. A short interruption period (i.e., 20 minutes) is likely to underestimate sedentary time among older adults. PMID:23752299

  14. Existence of time-periodic weak solutions to the stochastic Navier-Stokes equations around a moving body

    SciTech Connect

    Chen, Feng E-mail: hanyc@jlu.edu.cn; Han, Yuecai E-mail: hanyc@jlu.edu.cn

    2013-12-15

    The existence of time-periodic stochastic motions of an incompressible fluid is obtained. Here the fluid is subject to a time-periodic body force and an additional time-periodic stochastic force that is produced by a rigid body moves periodically stochastically with the same period in the fluid.

  15. 40 CFR 93.162 - Emissions beyond the time period covered by the SIP.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... covered by the SIP. 93.162 Section 93.162 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 93.162 Emissions beyond the time period covered by the SIP. If a Federal action would result in total... period covered by the SIP, the Federal agency can: (a) Demonstrate conformity with the last...

  16. NHEXAS PHASE I REGION 5 STUDY--TIME-ACTIVITY DIARY QUESTIONNAIRE DATA (ALL MONITORING PERIODS)

    EPA Science Inventory

    This data set includes responses for 249 participants with a total of 428 time-activity diaries. Some participants were studied for more than one monitoring period. The Time Diary and Activity Questionnaire was used for collecting data on detailed (daily) time and location inform...

  17. Cardiomyopathy Induced by Pulmonary Sequestration in a 50-Year-Old Man

    PubMed Central

    Chatelain, Shaun; Comp, Robert A.; Grace, R. Randal

    2015-01-01

    A 50-year-old black man presented at the emergency department with midsternal, nonradiating chest pressure and chronic dyspnea on exertion. Four years before the current admission, he had been diagnosed with nonischemic cardiomyopathy at another facility. After our complete evaluation, we suspected that his symptoms arose from left-to-left shunting in association with pulmonary sequestration, a congenital malformation. Our preliminary diagnosis of secondary dilated cardiomyopathy was confirmed by normalization of the patient's ventricular size and function after lobectomy. To our knowledge, this patient is the oldest on record to present with cardiomyopathy consequent to pulmonary sequestration. His case is highly unusual because of his age and the rapid resolution of his symptoms after lobectomy. We believe that pulmonary sequestration should be included in the differential diagnosis of dilated cardiomyopathy. PMID:25873803

  18. [The 50-year-old women or older: preventive actions to the HIV infection].

    PubMed

    Rodrigues, Daniela Angelo de Lima; Praça, Neide de Souza

    2010-06-01

    The present study is a qualitative research which aimed to verify the adoption of preventive measures on the transmission of HIV in 50-year-old women or older, who lived in poor communities and were assisted by the Family Health Program in São Paulo, Brazil. Medical Anthropology has been adopted as a theoretical reference, as well as the Discourse of the Collective Individual for data analysis. Thirteen women were interviewed and three discourses were presented: prevention appreciation, invisibility of HIV/AIDS and the rejection of the use of condom. The analysis showed that the group did not realize the risk of contamination through sexual intercourse due to their trust in the partner's loyalty. The casual use of condoms was taken into consideration just out of curiosity. The preventive actions adopted need more scientific support. The results point out the necessity of planning and implementing interventions which are culturally based and directed to the studied segment. PMID:21500513

  19. A review of 50 years of aerodynamic research with NACA/NASA

    NASA Technical Reports Server (NTRS)

    Spearman, M. Leroy

    1994-01-01

    Continuous improvements in flight systems have occurred over the past 50 years due, in part, to continuous improvements in aerodynamic research techniques and capabilities. This paper traces that research from the first-hand perspective of the author who, beginning in 1944, has taken part in the NACA/NASA aerodynamic research effort through studies in low-speed wind tunnels, high-speed subsonic tunnels, transonic tunnels, supersonic tunnels, and hypersonic tunnels. New problems were found as systems advanced from low-speed propeller-driven designs to more sophisticated high-speed jet- and rocket-propelled designs. The paper reviews some of these problems and reflects on some of the solutions that have been developed in the course of various aerodynamic research programs in the past. Some of the factors, both technical and nontechnical, that have influenced the aerodynamic design, research, and development of various flight systems will be mentioned.

  20. Association of American Veterinary Medical Colleges (AAVMC): 50 Years of History and Service.

    PubMed

    Maccabe, Andrew T; Crawford, Lester; Heider, Lawrence E; Hooper, Billy; Mann, Curt J; Pappaioanou, Marguerite

    2015-01-01

    The mission of the Association of American Veterinary Medical Colleges (AAVMC) is to advance the quality of academic veterinary medicine. Founded in 1966 by the 18 US colleges of veterinary medicine and 3 Canadian colleges of veterinary medicine then in existence, the AAVMC is celebrating 50 years of public service. Initially, the AAVMC comprised the Council of Deans, the Council of Educators, and the Council of Chairs. In 1984, the tri-cameral structure was abandoned and a new governing structure with a board of directors was created. In 1997, the AAVMC was incorporated in Washington, DC and a common application service was created. Matters such as workforce issues and the cost of veterinary medical education have persisted for decades. The AAVMC is a champion of diversity in the veterinary profession and a strong advocate for One Health. The AAVMC has adopted a global perspective as more international colleges of veterinary medicine have earned COE accreditation and become members. PMID:26673207

  1. Microstructure of 50 year old SCK CEN BR1 research reactor fuel

    SciTech Connect

    Leenaers, A.; Berghe, S. van den

    2008-07-15

    The BR1 research reactor at SCK CEN, Mol (Belgium) has a graphite core matrix loaded with fuel rods consisting of a natural uranium slug in an aluminum cladding. Fabrication reports show the application of a so-called AlSi bonding layer and an U(Al,Si){sub 3} anti-diffusion layer on the natural uranium fuel slug to limit the interaction between the uranium fuel and aluminum cladding. The BR1 reactor is in operation since 1956 and still contains its original fuel rods. After more than 50 years irradiation at low temperature, the integrity of some of the fuel rods is investigated. The microstructure of the fuel, bonding and anti-diffusion layer and cladding is analysed using optical microscopy (OM), scanning electron microscopy (SEM) and electron microprobe analysis (EPMA). (author)

  2. Transient reactive papulotranslucent acrokeratoderma in a 50-year-old woman: case report and review of the literature.

    PubMed

    Adişen, Esra; Karaca, Fulya; Gürer, Mehmet Ali

    2008-01-01

    A 50-year-old woman who presented with intermittent symmetric edema and wrinkling of the palms after soaking in water was found to have transient reactive papulotranslucent acrokeratoderma (TRPA). This is the oldest patient ever reported to have this condition. The patient was advised to avoid water exposure as much as possible and to wear gloves. Topical treatment with 5% salicylic acid in Vaseline also provided some relief. TRPA presents with translucent, white, confluent papules that become evident on the palms after 3-5 minutes' exposure to water (the so-called 'hand-in-the-bucket' sign) and resolve within a short time after drying. It is a rare disorder with fewer than 40 cases having been reported in the world literature. The disease is seen mostly in female patients, with ages ranging from 6 to 44 years prior to our case in a 50-year-old woman. The most common histologic findings are hyperkeratosis and dilated eccrine ostia. The etiopathogenesis of the disease remains unknown but a transitory structural or functional alteration of components of the stratum corneum or aberration of the sweat duct have been considered. TRPA has been reported in patients with cystic fibrosis and more recently, in patients taking selective cyclo-oxygenase-2 inhibitors. Therefore, the pathogenesis of the condition appears to be related to increased water absorption as a result of an increased epidermal sodium level. Treatment with barrier creams such as hydrophilic petrolatum, glycerin emollients, 5-20% salicylic acid in Vaseline, 10% urea cream, and 12% ammonium lactate cream have been reported. Cases with associated hyperhidrosis respond well to aluminum chloride-containing products. PMID:18973409

  3. [Active management of the third stage of labour (AMTSL) - the end of a 50 years-dogma?].

    PubMed

    Rath, W

    2013-10-01

    Post-partum haemorrhage (PPH) is the leading cause of maternal mortality worldwide. Since more than 50 years AMTSL has been proposed for the prevention of PPH and is still recommended in current guidelines. The 3 key components of AMTSL are the prophylactic administration of oxytocin, clamping and cutting of the umbilical cord immediately after delivery of the baby and controlled cord traction. AMTSL has proven to reduce the rate of severe PPH by 70%. Despite of the long tradition of AMTSL it is still unclear, which of the 3 components significantly contributes to the reduction in PPH. Cochrane analyses and a recent metaanalysis gave strong evidence, that prophylactic oxytocin administration reduces the risk of PPH significantly, however, the optimal dose and mode of application is still a matter of debate.Until a little while ago no randomized controlled studies exist regarding the significance of controlled cord traction and the time of cord clamping in AMTSL. A randomized WHO trial 2012 and the 2013 published TRACOR (Traction of the CORd)-trial from France could clearly demonstrate that controlled cord traction is not associated with a significant reduction in postpartum blood loss and in the risk of severe PPH. A Cochrane analysis 2008 and a recent randomized trial from Sweden came to the conclusion, that there are no significant -differences between early (< 15 s) and delayed (> 1-3 min) cord clamping in the reduction of PPH and severe PPH. Uterine massage after delivery of the placenta, placental cord drainage and umbilical vein injection of uterotonics after delivery of the baby as part of AMTSL are not evidence-based methods. It has taken 50 years since AMTSL was first described for it to become clear that prophylactic oxytocin is the most important and the only evidence-based component of AMTSL. Future guidelines and textbooks should consider these new -findings. PMID:24170442

  4. Existence and exponential stability of positive almost periodic solution for Nicholson's blowflies models on time scales.

    PubMed

    Li, Yongkun; Li, Bing

    2016-01-01

    In this paper, we first give a new definition of almost periodic time scales, two new definitions of almost periodic functions on time scales and investigate some basic properties of them. Then, as an application, by using a fixed point theorem in Banach space and the time scale calculus theory, we obtain some sufficient conditions for the existence and exponential stability of positive almost periodic solutions for a class of Nicholson's blowflies models on time scales. Finally, we present an illustrative example to show the effectiveness of obtained results. Our results show that under a simple condition the continuous-time Nicholson's blowflies model and its discrete-time analogue have the same dynamical behaviors. PMID:27468397

  5. Stabilization Wedges and the Management of Global Carbon for the next 50 years

    ScienceCinema

    Socolow, Robert [Princeton University, Princeton, New Jersey, United States

    2009-09-01

    More than 40 years after receiving a Ph.D. in physics, I am still working on problems where conservation laws matter. In particular, for the problems I work on now, the conservation of the carbon atom matters. I will tell the saga of an annual flow of 8 billion tons of carbon associated with the global extraction of fossil fuels from underground. Until recently, it was taken for granted that virtually all of this carbon will move within weeks through engines of various kinds and then into the atmosphere. For compelling environmental reasons, I and many others are challenging this complacent view, asking whether the carbon might wisely be directed elsewhere. To frame this and similar discussions, Steve Pacala and I introduced the 'stabilization wedge' in 2004 as a useful unit for discussing climate stabilization. Updating the definition, a wedge is the reduction of CO2 emissions by one billion tons of carbon per year in 2057, achieved by any strategy generated as a result of deliberate attention to global carbon. Each strategy uses already commercialized technology, generally at much larger scale than today. Implementing seven wedges should enable the world to achieve the interim goal of emitting no more CO2 globally in 2057 than today. This would place humanity, approximately, on a path to stabilizing CO2 at less than double the pre-industrial concentration, and it would put those at the helm in the following 50 years in a position to drive CO2 emissions to a net of zero in the following 50 years. Arguably, the tasks of the two half-centuries are comparably difficult.

  6. Benthic foraminiferal assemblages in Osaka Bay, southwestern Japan: Faunal changes over the last 50 years

    USGS Publications Warehouse

    Tsujimoto, Akira; Nomura, Ritsuo; Yasuhara, Moriaki; Yoshikawa, Shusaku

    2006-01-01

    Live benthic foraminiferal assemblages from surface sediment in Osaka Bay collected in 1999 were analyzed to characterize the distribution of the modern foraminiferal assemblages. Foraminiferal assemblages were compared with those of previous studies to document environmental changes in Osaka Bay over the past 50 years. Sixty-one species of foraminifera belonging to 37 genera were recognized from the 1999 surface sediment samples. An agglutinated assemblage containing Trochammina hadai and Eggerella advena is dominant in the inner part of the bay and is related to eutrophication. The foraminiferal assemblage in areas deeper than about 20 m is composed of Eggerella advena, Ammonia beccarii forma A, and Pseudorotalia gaimardii. This assemblage may be influenced by the large clockwise Okinose Circulation Current which extends throughout the western bay. Foraminiferal assemblages in Osaka Bay have changed dramatically during the last 50 years. The Trochammina hadai-Eggerella advena assemblage became established in the inner part of the bay, reflecting eutrophication that progressed from the 1960s through the 1970s. This assemblage became dominant in 1983, and typically dominated the inner part of the bay. From 1983 to 1999, however, the abundance of taxa belonging to this assemblage decreased greatly following implementation of 1973 Osaka City bylaws that restricted wastewater discharge. Changes in benthic assemblages such as the decrease of Ammonia beccarii forma A and increase of Eggerella advena have occurred in response to decreased incidence of red tides, and floral change in the species that cause these tides. The results of this study demonstrate that the abundance and distribution of benthic foraminifers in Osaka Bay are intimately related to environmental changes related to the urbanization of coastal areas. ?? by the Palaeontological Society of Japan.

  7. Noninvasive assessment of cardiomyopathy in normotensive diabetic patients between 20 and 50 years old

    SciTech Connect

    Bouchard, A.; Sanz, N.; Botvinick, E.H.; Phillips, N.; Heilbron, D.; Byrd, B.F. 3d.; Karam, J.H.; Schiller, N.B. )

    1989-08-01

    To further the understanding of diabetic heart disease, we tested the hypothesis that an asymptomatic group of normotensive diabetic patients between 20 and 50 years old had a restrictive cardiomyopathy independent of clinically significant coronary artery disease. Quantitative two-dimensional echocardiography and stress myocardial perfusion scintigraphy were performed to detect and characterize the cardiac abnormalities in this study group comprising 88 patients with rigorously classified diabetes and 65 volunteer control subjects. Diabetic patients were shown to have a mildly reduced left ventricular end-diastolic volume index: 50.1 +/- 8.2 and 52.1 +/- 14.7 mL/m2 for patients with type I and type II diabetes, respectively, versus 58.9 +/- 11.7 mL/m2 for control subjects. The left ventricular diastolic filling was also impaired in diabetic patients as reflected by a lower atrial emptying index: 0.73 +/- 0.24 and 0.76 +/- 0.3 for type I and type II diabetics, respectively, compared with 1.14 +/- 0.24 for control subjects. Exercise tolerance was normal in subjects with type I diabetes and slightly reduced in subjects with type II diabetes. Only one patient developed regional ischemia on thallium exercise testing. Using a comprehensive, noninvasive approach, we have shown that asymptomatic normotensive patients with type I or type II diabetes who were between 20 and 50 years old had a restrictive cardiomyopathy characterized by mildly reduced left ventricular end-diastolic volume and altered left ventricular compliance independent of critical coronary artery disease.

  8. Stabilization Wedges and the Management of Global Carbon for the next 50 years

    SciTech Connect

    Socolow, Robert

    2007-04-18

    More than 40 years after receiving a Ph.D. in physics, I am still working on problems where conservation laws matter. In particular, for the problems I work on now, the conservation of the carbon atom matters. I will tell the saga of an annual flow of 8 billion tons of carbon associated with the global extraction of fossil fuels from underground. Until recently, it was taken for granted that virtually all of this carbon will move within weeks through engines of various kinds and then into the atmosphere. For compelling environmental reasons, I and many others are challenging this complacent view, asking whether the carbon might wisely be directed elsewhere. To frame this and similar discussions, Steve Pacala and I introduced the 'stabilization wedge' in 2004 as a useful unit for discussing climate stabilization. Updating the definition, a wedge is the reduction of CO2 emissions by one billion tons of carbon per year in 2057, achieved by any strategy generated as a result of deliberate attention to global carbon. Each strategy uses already commercialized technology, generally at much larger scale than today. Implementing seven wedges should enable the world to achieve the interim goal of emitting no more CO2 globally in 2057 than today. This would place humanity, approximately, on a path to stabilizing CO2 at less than double the pre-industrial concentration, and it would put those at the helm in the following 50 years in a position to drive CO2 emissions to a net of zero in the following 50 years. Arguably, the tasks of the two half-centuries are comparably difficult.

  9. Stabilization Wedges and the Management of Global Carbon for the Next 50 Years

    SciTech Connect

    Socolow, Robert

    2007-04-18

    More than 40 years after receiving a Ph.D. in physics, I am still working on problems where conservation laws matter. In particular, for the problems I work on now, the conservation of the carbon atom matters. I will tell the saga of an annual flow of 8 billion tons of carbon associated with the global extraction of fossil fuels from underground. Until recently, it was taken for granted that virtually all of this carbon will move within weeks through engines of various kinds and then into the atmosphere. For compelling environmental reasons, I and many others are challenging this complacent view, asking whether the carbon might wisely be directed elsewhere. To frame this and similar discussions, Steve Pacala and I introduced the 'stabilization wedge' in 2004 as a useful unit for discussing climate stabilization. Updating the definition, a wedge is the reduction of CO2 emissions by one billion tons of carbon per year in 2057, achieved by any strategy generated as a result of deliberate attention to global carbon. Each strategy uses already commercialized technology, generally at much larger scale than today. Implementing seven wedges should enable the world to achieve the interim goal of emitting no more CO2 globally in 2057 than today. This would place humanity, approximately, on a path to stabilizing CO2 at less than double the pre-industrial concentration, and it would put those at the helm in the following 50 years in a position to drive CO2 emissions to a net of zero in the following 50 years. Arguably, the tasks of the two half-centuries are comparably difficult.

  10. An infinite branching hierarchy of time-periodic solutions of the Benjamin-Ono equation

    SciTech Connect

    Wilkening, Jon

    2008-07-01

    We present a new representation of solutions of the Benjamin-Ono equation that are periodic in space and time. Up to an additive constant and a Galilean transformation, each of these solutions is a previously known, multi-periodic solution; however, the new representation unifies the subset of such solutions with a fixed spatial period and a continuously varying temporal period into a single network of smooth manifolds connected together by an infinite hierarchy of bifurcations. Our representation explicitly describes the evolution of the Fourier modes of the solution as well as the particle trajectories in a meromorphic representation of these solutions; therefore, we have also solved the problem of finding periodic solutions of the ordinary differential equation governing these particles, including a description of a bifurcation mechanism for adding or removing particles without destroying periodicity. We illustrate the types of bifurcation that occur with several examples, including degenerate bifurcations not predicted by linearization about traveling waves.

  11. A statistical model for the timing of earthquakes and volcanic eruptions influenced by periodic processes

    NASA Astrophysics Data System (ADS)

    Jupp, Tim E.; Pyle, David M.; Mason, Ben G.; Dade, W. Brian

    2004-02-01

    Evidence of nonuniformity in the rate of seismicity and volcanicity has been sought on a variety of timescales ranging from ˜12.4 hours (tidal) to 103-104 years (climatic), but the results are mixed. Here, we propose a simple conceptual model for the influence of periodic processes on the frequency of geophysical "failure events" such as earthquakes and volcanic eruptions. In our model a failure event occurs at a "failure time" tF = tI + tR which is controlled by an "initiation event" at the "initiation time" tI and by the "response time" of the system tR. We treat each of the initiation time, the response time, and the failure time as random variables. In physical terms, we define the initiation time to be the time at which a "load function" exceeds a "strength function," and we imagine that the response time tR corresponds to a physical process such as crack propagation or the movement of magma. Assuming that the magnitude and frequency of the periodic process are known, we calculate the statistical distribution of the initiation times on the assumption that the load and strength functions are otherwise linear in time. This allows the distribution of the failure times to be calculated if the distribution of the response times is known also. The quantitative predictions of this simple theory are compared with some examples of observed periodicity in seismic and volcanic activity at tidal and annual timescales.

  12. Time periodic spatial disorder in a complex Ginzburg{endash}Landau equation

    SciTech Connect

    Bazhenov, M.; Rabinovich, M.; Rubchinsky, L.

    1996-06-01

    The phenomenon of time-periodic evolution of spatial chaos (1) is investigated in the frame of a one and two-dimensional complex Ginzburg{endash}Landau equation. It is found that there exists a region of the parameters at which a disordered spatial distribution of the field behaves periodically in time; the boundaries of this region are determined. A system of ordinary differential equations describing spatial disorder is derived. The effect of the size of the system on the shape and period of oscillations is investigated. It is established that in a two-dimensional case the regime of time periodic spatial disorder arises only in the narrow band and the critical width of the band is estimated. The phenomenon investigated in this paper indicates that a family of limit cycles with finite basins may exist in the functional phase space of complex Ginzburg{endash}Landau equation in finite regions of the parameters. {copyright} {ital 1996 American Institute of Physics.}

  13. Dynamics of phase slips in systems with time-periodic modulation.

    PubMed

    Gandhi, Punit; Knobloch, Edgar; Beaume, Cédric

    2015-12-01

    The Adler equation with time-periodic frequency modulation is studied. A series of resonances between the period of the frequency modulation and the time scale for the generation of a phase slip is identified. The resulting parameter space structure is determined using a combination of numerical continuation, time simulations, and asymptotic methods. Regions with an integer number of phase slips per period are separated by regions with noninteger numbers of phase slips and include canard trajectories that drift along unstable equilibria. Both high- and low-frequency modulation is considered. An adiabatic description of the low-frequency modulation regime is found to be accurate over a large range of modulation periods. PMID:26764781

  14. Frequency domain system identification of helicopter rotor dynamics incorporating models with time periodic coefficients

    NASA Astrophysics Data System (ADS)

    Hwang, Sunghwan

    1997-08-01

    One of the most prominent features of helicopter rotor dynamics in forward flight is the periodic coefficients in the equations of motion introduced by the rotor rotation. The frequency response characteristics of such a linear time periodic system exhibits sideband behavior, which is not the case for linear time invariant systems. Therefore, a frequency domain identification methodology for linear systems with time periodic coefficients was developed, because the linear time invariant theory cannot account for sideband behavior. The modulated complex Fourier series was introduced to eliminate the smearing effect of Fourier series expansions of exponentially modulated periodic signals. A system identification theory was then developed using modulated complex Fourier series expansion. Correlation and spectral density functions were derived using the modulated complex Fourier series expansion for linear time periodic systems. Expressions of the identified harmonic transfer function were then formulated using the spectral density functions both with and without additive noise processes at input and/or output. A procedure was developed to identify parameters of a model to match the frequency response characteristics between measured and estimated harmonic transfer functions by minimizing an objective function defined in terms of the trace of the squared frequency response error matrix. Feasibility was demonstrated by the identification of the harmonic transfer function and parameters for helicopter rigid blade flapping dynamics in forward flight. This technique is envisioned to satisfy the needs of system identification in the rotating frame, especially in the context of individual blade control. The technique was applied to the coupled flap-lag-inflow dynamics of a rigid blade excited by an active pitch link. The linear time periodic technique results were compared with the linear time invariant technique results. Also, the effect of noise processes and initial

  15. Estimating least-developed countries' vulnerability to climate-related extreme events over the next 50 years.

    PubMed

    Patt, Anthony G; Tadross, Mark; Nussbaumer, Patrick; Asante, Kwabena; Metzger, Marc; Rafael, Jose; Goujon, Anne; Brundrit, Geoff

    2010-01-26

    When will least developed countries be most vulnerable to climate change, given the influence of projected socio-economic development? The question is important, not least because current levels of international assistance to support adaptation lag more than an order of magnitude below what analysts estimate to be needed, and scaling up support could take many years. In this paper, we examine this question using an empirically derived model of human losses to climate-related extreme events, as an indicator of vulnerability and the need for adaptation assistance. We develop a set of 50-year scenarios for these losses in one country, Mozambique, using high-resolution climate projections, and then extend the results to a sample of 23 least-developed countries. Our approach takes into account both potential changes in countries' exposure to climatic extreme events, and socio-economic development trends that influence countries' own adaptive capacities. Our results suggest that the effects of socio-economic development trends may begin to offset rising climate exposure in the second quarter of the century, and that it is in the period between now and then that vulnerability will rise most quickly. This implies an urgency to the need for international assistance to finance adaptation. PMID:20080585

  16. Estimating least-developed countries’ vulnerability to climate-related extreme events over the next 50 years

    PubMed Central

    Patt, Anthony G.; Tadross, Mark; Nussbaumer, Patrick; Asante, Kwabena; Metzger, Marc; Rafael, Jose; Goujon, Anne; Brundrit, Geoff

    2010-01-01

    When will least developed countries be most vulnerable to climate change, given the influence of projected socio-economic development? The question is important, not least because current levels of international assistance to support adaptation lag more than an order of magnitude below what analysts estimate to be needed, and scaling up support could take many years. In this paper, we examine this question using an empirically derived model of human losses to climate-related extreme events, as an indicator of vulnerability and the need for adaptation assistance. We develop a set of 50-year scenarios for these losses in one country, Mozambique, using high-resolution climate projections, and then extend the results to a sample of 23 least-developed countries. Our approach takes into account both potential changes in countries’ exposure to climatic extreme events, and socio-economic development trends that influence countries’ own adaptive capacities. Our results suggest that the effects of socio-economic development trends may begin to offset rising climate exposure in the second quarter of the century, and that it is in the period between now and then that vulnerability will rise most quickly. This implies an urgency to the need for international assistance to finance adaptation. PMID:20080585

  17. A framework for periodic outlier pattern detection in time-series sequences.

    PubMed

    Rasheed, Faraz; Alhajj, Reda

    2014-05-01

    Periodic pattern detection in time-ordered sequences is an important data mining task, which discovers in the time series all patterns that exhibit temporal regularities. Periodic pattern mining has a large number of applications in real life; it helps understanding the regular trend of the data along time, and enables the forecast and prediction of future events. An interesting related and vital problem that has not received enough attention is to discover outlier periodic patterns in a time series. Outlier patterns are defined as those which are different from the rest of the patterns; outliers are not noise. While noise does not belong to the data and it is mostly eliminated by preprocessing, outliers are actual instances in the data but have exceptional characteristics compared with the majority of the other instances. Outliers are unusual patterns that rarely occur, and, thus, have lesser support (frequency of appearance) in the data. Outlier patterns may hint toward discrepancy in the data such as fraudulent transactions, network intrusion, change in customer behavior, recession in the economy, epidemic and disease biomarkers, severe weather conditions like tornados, etc. We argue that detecting the periodicity of outlier patterns might be more important in many sequences than the periodicity of regular, more frequent patterns. In this paper, we present a robust and time efficient suffix tree-based algorithm capable of detecting the periodicity of outlier patterns in a time series by giving more significance to less frequent yet periodic patterns. Several experiments have been conducted using both real and synthetic data; all aspects of the proposed approach are compared with the existing algorithm InfoMiner; the reported results demonstrate the effectiveness and applicability of the proposed approach. PMID:23757597

  18. Finding hidden periodic signals in time series - an application to stock prices

    NASA Astrophysics Data System (ADS)

    O'Shea, Michael

    2014-03-01

    Data in the form of time series appear in many areas of science. In cases where the periodicity is apparent and the only other contribution to the time series is stochastic in origin, the data can be `folded' to improve signal to noise and this has been done for light curves of variable stars with the folding resulting in a cleaner light curve signal. Stock index prices versus time are classic examples of time series. Repeating patterns have been claimed by many workers and include unusually large returns on small-cap stocks during the month of January, and small returns on the Dow Jones Industrial average (DJIA) in the months June through September compared to the rest of the year. Such observations imply that these prices have a periodic component. We investigate this for the DJIA. If such a component exists it is hidden in a large non-periodic variation and a large stochastic variation. We show how to extract this periodic component and for the first time reveal its yearly (averaged) shape. This periodic component leads directly to the `Sell in May and buy at Halloween' adage. We also drill down and show that this yearly variation emerges from approximately half of the underlying stocks making up the DJIA index.

  19. Rank One Strange Attractors in Periodically Kicked Predator-Prey System with Time-Delay

    NASA Astrophysics Data System (ADS)

    Yang, Wenjie; Lin, Yiping; Dai, Yunxian; Zhao, Huitao

    2016-06-01

    This paper is devoted to the study of the problem of rank one strange attractor in a periodically kicked predator-prey system with time-delay. Our discussion is based on the theory of rank one maps formulated by Wang and Young. Firstly, we develop the rank one chaotic theory to delayed systems. It is shown that strange attractors occur when the delayed system undergoes a Hopf bifurcation and encounters an external periodic force. Then we use the theory to the periodically kicked predator-prey system with delay, deriving the conditions for Hopf bifurcation and rank one chaos along with the results of numerical simulations.

  20. A Recurrence Time versus Orbital Period Relation for the Z Camelopardalis Stars

    NASA Astrophysics Data System (ADS)

    Shafter, Allen W.; Cannizzo, John K.; Waagen, Elizabeth O.

    2005-09-01

    We examine AAVSO (American Association of Variable Star Observers) light curves of 16 Z Camelopardalis systems with measured orbital periods, with particular focus on intervals away from standstill. During these times, most of the systems display a sawtooth-like outburst behavior, with quiescent intervals comparable to the outburst durations. We report the discovery of a linear relation between the characteristic outburst period and orbital period for these systems, which is given by =62.0(+/-7.7)Porb(days)+2.41(+/-1.87).

  1. Case Records of the Massachusetts General Hospital. Case 30-2015: A 50-Year-Old Man with Cardiogenic Shock.

    PubMed

    Wheeler, Thurman M; Baker, Joshua N; Chad, David A; Zilinski, Jodi L; Verzosa, Stacey; Mordes, Daniel A

    2015-09-24

    A 50-year-old man with a history of cardiomyopathy and progressive muscle weakness was admitted with cardiogenic shock. Electroencephalography showed total suppression of cerebral activity; ventilator support was withdrawn, and he died. An autopsy was performed. PMID:26398074

  2. Curly tail: a 50-year history of the mouse spina bifida model.

    PubMed

    van Straaten, H W; Copp, A J

    2001-04-01

    This paper reviews 50 years of progress towards understanding the aetiology and pathogenesis of neural tube defects (NTD) in the curly tail (ct) mutant mouse. More than 45 papers have been published on various aspects of curly tail with the result that it is now the best understood mouse model of NTD pathogenesis. The failure of closure of the spinal neural tube, which leads to spina bifida in this mouse, has been traced back to a tissue-specific defect of cell proliferation in the tail bud of the E9.5 embryo. This cell proliferation defect results in a growth imbalance in the caudal region that generates ventral curvature of the body axis. Neurulation movements are opposed, leading to delayed neuropore closure and spina bifida, or tail defects. It is interesting to reflect that these advances have been achieved in the absence of information on the nature of the ct gene product, which remains unidentified. In addition to the principal ct gene, which maps to distal Chromosome 4, the curly tail phenotype is influenced by several modifier genes and by environmental factors. NTD in curly tail are resistant to folic acid, as is thought to be the case in 30% of human NTD, whereas they can be prevented by myo-inositol. These and other features of NTD in this system bear striking similarities to the situation in humans, making curly tail a model for understanding a sub-type folic acid-resistant human NTD. PMID:11396850

  3. Earth Observations from Space: The First 50 Years of Scientific Achievements

    NASA Astrophysics Data System (ADS)

    Minster, B.; Campbell, J. W.; Dozier, J.; Fleming, J. R.; Gille, J. C.; Hartmann, D. L.; Jezek, K.; Kidder, S.; Ramankutty, N.; Thompson, A.; Ustin, S. L.; Yoder, J.; Probst, L.; Mengelt, C.

    2007-12-01

    Observing the Earth from space over the last five decades has fundamentally transformed the way people view our home planet. The image of the "blue marble" is taken for granted now, but it was revolutionary when it was first taken in 1972 by the crew on Apollo 17. Since then, the capability to look at Earth from space has grown increasingly sophisticated and evolved from simple photographs to quantitative measurements of Earth properties such as temperature, atmospheric gases, and exact elevation of land and ocean. Consequently, every new method of imaging the Earth from space has resulted in scientific accomplishments that have enabled new discoveries, transformed the field, refined scientific understanding, opened new avenues of research, or provided important societal benefits by improving the predictability of Earth system processes. This National Research Council (NRC) study highlights selected scientific achievements made possible by the first 50 years of Earth satellite observations by space-faring nations. It follows on a recent report from the NRC entitled "Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond" (NRC 2007), also referred to as the "decadal study."

  4. Earth Observations from Space: The First 50 Years of Scientific Achievements

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Observing Earth from space over the past 50 years has fundamentally transformed the way people view our home planet. The image of the "blue marble" is taken for granted now, but it was revolutionary when taken in 1972 by the crew on Apollo 17. Since then the capability to look at Earth from space has grown increasingly sophisticated and has evolved from simple photographs to quantitative measurements of Earth properties such as temperature, concentrations of atmospheric trace gases, and the exact elevation of land and ocean. Imaging Earth from space has resulted in major scientific accomplishments; these observations have led to new discoveries, transformed the Earth sciences, opened new avenues of research, and provided important societal benefits by improving the predictability of Earth system processes. This report highlights the scientific achievements made possible by the first five decades of Earth satellite observations by space-faring nations. It follows on a recent report from the National Research Council (NRC) entitled Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, also referred to as the "decadal survey." Recognizing the increasing need for space observations, the decadal survey identifies future directions and priorities for Earth observations from space. This companion report was requested by the National Aeronautics and Space Administration (NASA) to highlight, through selected examples, important past contributions of Earth observations from space to our current understanding of the planet.

  5. Occupational Exposure to Hydrazine and Subsequent Risk of Lung Cancer: 50-Year Follow-Up

    PubMed Central

    Morris, Joan K.; Wald, Nicholas J.; Springett, Anna L.

    2015-01-01

    Purpose Hydrazine is carcinogenic in animals, but there is inadequate evidence to determine if it is carcinogenic in humans. This study aimed to evaluate the association between hydrazine exposure and the risk of lung cancer. Methods The cause specific mortality rates of a cohort of 427 men who were employed at an English factory that produced hydrazine between 1945 and 1971 were compared with national mortality rates. Results By the end of December 2012 205 deaths had occurred. For men in the highest exposure category with greater than two years exposure and after more than ten years since first exposure the relative risks compared with national rates were: 0.85 (95% CI: 0.18–2.48) for lung cancer, 0.61 (95% CI: 0.07–2.21) for cancers of the digestive system, and 0.44 (95% CI: 0.05–1.57) for other cancers. Conclusions After 50 years of follow up, the results provide no evidence of an increased risk of death from lung cancer or death from any other cause. PMID:26394402

  6. 50 Years of renal physiology from one man and the perfused tubule: Maurice B. Burg.

    PubMed

    Hamilton, Kirk L; Moore, Antoni B

    2016-08-01

    Technical advancements in research techniques in science are made in slow increments. Even so, large advances from insight and hard work of an individual with a single technique can have astonishing ramifications. Here, we examine the impact of Dr. Maurice B. Burg and the isolated perfused renal tubule technique and celebrate the 50th anniversary of the publication by Dr. Burg and his colleagues of their landmark paper in the American Journal of Physiology in 1966. In this study, we have taken a scientific visualization approach to study the scientific contributions of Dr. Burg and the isolated perfused tubule preparation as determining research impact by the number of research students, postdoctoral fellows, visiting scientists, and national and international collaborators. Additionally, we have examined the research collaborations (first and second generation scientists), established the migrational visualization of the first generation scientists who worked directly with Dr. Burg, quantified the metrics indices, identified and quantified the network of coauthorship of the first generation scientists with their second generation links, and determined the citations analyses of outputs of Dr. Burg and/or his first generation collaborators as coauthors. We also review the major advances in kidney physiology that have been made with the isolated perfused tubule technique. Finally, we are all waiting for the discoveries that the isolated perfused preparation technique will bring during the next 50 years. PMID:27122544

  7. Applications of mass spectrometry in drug metabolism: 50 years of progress.

    PubMed

    Wen, Bo; Zhu, Mingshe

    2015-02-01

    Mass spectrometry plays a pivotal role in drug metabolism studies, which are an integral part of drug discovery and development nowadays. Metabolite identification has become critical to understanding the metabolic fate of drug candidates and to aid lead optimization with improved metabolic stability, toxicology and efficacy profiles. Ever since the introduction of atmospheric ionization techniques in the early 1990s, liquid chromatography coupled with mass spectrometry (LC/MS) has secured a central role as the predominant analytical platform for metabolite identification as LC and MS technologies continually advanced. In this review, we discuss the evolution of both MS technology and its applications over the past 50 years to meet the increasing demand of drug metabolism studies. These advances include ionization sources, mass analyzers, a wide range of MS acquisition strategies and data mining tools that have substantially accelerated the metabolite identification process and changed the overall drug metabolism landscape. Exemplary applications for characterization and identification of both small-molecule xenobiotics and biological macromolecules are described. In addition, this review discusses novel MS technologies and applications, including xenobiotic metabolomics that hold additional promise for advancing drug metabolism research, and offers thoughts on remaining challenges in studying the metabolism and disposition of drugs and other xenobiotics. PMID:25639893

  8. Influenza Vaccine-Induced CNS Demyelination in a 50-Year-Old Male

    PubMed Central

    Sacheli, Aaron; Bauer, Raymond

    2014-01-01

    Patient: Male, 50 Final Diagnosis: Acute post-vaccination CNS demyelinating disorder Symptoms: Blurred vision • hemiparesis • hemiplegia • hypertonia • itching • paresthesia Medication: — Clinical Procedure: MRI Specialty: Neurology Objective: Rare disease Background: There are several categories of primary inflammatory demyelinating disorders, which comprise clinically similar neurologic sequelae. Of interest, clinically isolated syndrome (CIS) and acute disseminated encephalomyelitis (ADEM) are 2 demyelinating conditions of the central nervous system (CNS), whose clinical similarity pose a significant challenge to definitive diagnosis. Yet, both remain important clinical considerations in patients with neurologic signs and symptoms in the context of recent vaccination. Case Report: We report a case of a 50-year-old Caucasian male with a course of progressive, focal, neurologic deficits within 24 h after receiving the influenza vaccine. Subsequent work-up revealed the possibility of an acute central nervous system (CNS) demyelinating episode secondary to the influenza vaccine, best described as either CIS or ADEM. Conclusions: Case reports of CNS demyelination following vaccinations have been previously noted, most often occurring in the context of recent influenza vaccination. This report serves to document a case of CNS demyelination occurring 24 h after influenza vaccination in a middle-aged patient, and will describe some salient features regarding the differential diagnosis of CIS and ADEM, as well as their potential management. PMID:25175754

  9. Thoracic outlet syndrome: a 50-year experience at Baylor University Medical Center

    PubMed Central

    Kourlis, Harry

    2007-01-01

    During the past 5 decades, the recognition and management of thoracic outlet syndrome (TOS) have evolved. This article elucidates these changes and improvements in the diagnosis and management of TOS at Baylor University Medical Center. The most remarkable change over the past 50 years is the use of nerve conduction velocity to diagnose and monitor patients with nerve compression. Recognition that procedures such as breast implantation and median sternotomy may produce TOS has been revealing. Prompt thrombolysis followed by surgical venous decompression for Paget-Schroetter syndrome has markedly improved results compared with the conservative anticoagulation approach; thrombolysis and prompt first rib resection is the optimal treatment for most patients with Paget-Schroetter syndrome. Complete first rib extirpation at the initial procedure markedly reduces the incidence of recurrent neurologic symptoms or the need for a second procedure. Chest pain or pseudoangina can be caused by TOS. Dorsal sympathectomy is helpful for patients with sympathetic maintained pain syndrome or causalgia and patients with recurrent TOS symptoms who need a second procedure. PMID:17431445

  10. Unilateral lower limb lymphedema resulting from a heart surgery performed 50 years prior

    PubMed Central

    Onoda, Satoshi; Miura, Yuki; Sugiyama, Narushi

    2015-01-01

    Introduction Lymphedema is classified into two main types: secondary lymphedema accompanied by lymph node excision surgery or radiotherapy; and idiopathic lymphedema. Here we experienced a very rare case of lymphatic edema resulting from cardiac surgery that the patient underwent 50 years previously. Presentation of case A 62-year-old woman experienced progressive unilateral lower leg lymphedema for recent years. After undergoing cardiac surgery at another hospital at the age of 12 years, she gradually developed left lower leg edema. The cause of the edema was unclear and it remained untreated. Her edema symptoms gradually worsened in recent years, so she consulted the plastic surgery division of our hospital. Discusssion Perhaps the lymphatic structures of affected individuals differ prior to disease onset. If the mechanism of lymphatic edema outbreak is elucidated, patients needing conservative and surgical therapy might be more easily identified. Knowing the outbreak mechanism of lymphatic edema would definitely ease the investigation of an unconventional case like this one. Conservative treatments for lymphedema, such as self-massage and compression therapy using garments, were immediately started. With these treatments, the leg volume and edema symptoms reduced. Conclusion The research on the cause of this case may be important step for elucidating the source of secondary lymphatic edema. PMID:26719996

  11. Ceremony at CCAS to kick off year-long celebration of 50 years of space launches

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Cape Canaveral Air Station's (CCAS) Complex 3/4, officials held a ceremony kicking off a year-long series of events commemorating 50 years of launches from the Space Coast that began with the Bumper rockets. At right, Norris Gray, a Bumper Program veteran, unveils a street sign that will be used to mark the road leading to the launch complex from which Bumper was launched. Seen on the stage are, left to right, Lt. Col. Randall K. Horn (at the podium), Commander, CCAS; Congressman David Weldon, 15th Congressional District of the State of Florida; Lieutenant Governor of the State of Florida Frank T. Brogan; Center Director Roy D. Bridges; and Executive Director Edward F. Gormel, Joint Performance Management Office. Also present (but not seen) is Brig. Gen. Donald P. Pettit, Commander, 45th Space Wing. After six Bumper launches at White Sands Proving Grounds, N.M., and a failed Bumper 7, a successful Bumper 8 lifted off July 24, 1950, from Complex 3/4 to conduct aerodynamic investigations around Mach 7 at relatively low altitudes. The kick-off event also inaugurated a student art contest to design a commemorative etching. The winning artwork will be permanently displayed on a 24-inch black granite square in the U.S. space Walk hall of Fame in Titusville, Fla.

  12. Orthogonal electrocardiogram, apex cardiogram, and atrial sound in normotensive and hypertensive 50-year-old men.

    PubMed Central

    Wikstrand, J; Berglund, G; Wilhelmsen, L; Wallentin, I

    1976-01-01

    The prevalence of signs of heart involvement was studied non-invasively in a group of untreated hypertensives (n=35) and a reference group (n=73), all derived from a random population sample of 50-year-old men. Signs of left ventricular hypertrophy were studied by means of orthogonal electrocardiography and conventional electrocardiography. Signs of decreased distensibility of the left ventricle were studied by apex cardiography and registration of atrial sounds. Left ventricular hypertrophy among hypertensives was significantly more common according to orthogonal electrocardiography (33%) than according to conventional electrocardiography (9%), indicating that the former may be a better method for detection of left ventricular hypertrophy than the latter. In the hypertension group the amplitude of the R wave in lead X on orthogonal electrocardiography was positively correlated to casual diastolic blood pressure (r=0-40) and to diastolic blood pressure after one hour's rest (r=0-65). The degree of pressure load leading to left ventricular hypertrophy seems to be better reflected by resting than by casual blood pressure. There was no hypertensive subject with both signs of left ventricular hypertrophy on orthogonal electrocardiography and either an a/H ratio over 15 per cent or an abnormal atrial sound, indicating two different forms of cardiac involvement as the result of hypertension. Casual blood pressures became normal during rest in hypertensives with a/H ratio over 15 per cent on apex cardiography or abnormal atrial sound, not in hypertensives with signs of left ventricular hypertrophy on orthogonal electrocardiography. PMID:135571

  13. How far we have come in the last 50 years in smoking attitudes and actions.

    PubMed

    Burns, David

    2014-02-01

    Dramatic changes in smoking behavior and attitudes about smoking have occurred over the 50-year interval since the release of the 1964 smoking and health report to the Surgeon General. Between 1965 and 2011, adult prevalence of cigarette smoking fell from 51.9 to 21.6% among men and from 33.9 to 16.5% among women, with an increasing fraction of smokers who do not smoke every day. Federal taxes have increased from $0.08 in 1965 to $1.01, with even larger increases in many state taxes. Workplace restrictions on smoking have increased from only 3% of workers protected by workplace smoking bans in 1986 (e.g., those working in fireworks factories) to more than 70% of workers being protected in 1999. Equally dramatic changes have occurred in restrictions on smoking in the home. The evaporation of the remaining societal support for smoking may be an important part of the "end game" for cigarette smoking in the United States. PMID:24575990

  14. The Demoiselle of X-Inactivation: 50 Years Old and As Trendy and Mesmerising As Ever

    PubMed Central

    Morey, Céline; Avner, Philip

    2011-01-01

    In humans, sexual dimorphism is associated with the presence of two X chromosomes in the female, whereas males possess only one X and a small and largely degenerate Y chromosome. How do men cope with having only a single X chromosome given that virtually all other chromosomal monosomies are lethal? Ironically, or even typically many might say, women and more generally female mammals contribute most to the job by shutting down one of their two X chromosomes at random. This phenomenon, called X-inactivation, was originally described some 50 years ago by Mary Lyon and has captivated an increasing number of scientists ever since. The fascination arose in part from the realisation that the inactive X corresponded to a dense heterochromatin mass called the “Barr body” whose number varied with the number of Xs within the nucleus and from the many intellectual questions that this raised: How does the cell count the X chromosomes in the nucleus and inactivate all Xs except one? What kind of molecular mechanisms are able to trigger such a profound, chromosome-wide metamorphosis? When is X-inactivation initiated? How is it transmitted to daughter cells and how is it reset during gametogenesis? This review retraces some of the crucial findings, which have led to our current understanding of a biological process that was initially considered as an exception completely distinct from conventional regulatory systems but is now viewed as a paradigm “par excellence” for epigenetic regulation. PMID:21811421

  15. The Axon Initial Segment, 50Years Later: A Nexus for Neuronal Organization and Function.

    PubMed

    Leterrier, Christophe

    2016-01-01

    The axon initial segment is a highly specialized neuronal compartment, identified almost 50years ago by the pioneers of electron microscopy. Located in the first 50μm of the axon, it contains unique cytoskeletal features and concentrates a repertoire of specific scaffold and membrane proteins that assembles just after axon determination. The axon initial segment (AIS) supports two crucial physiological functions of the mature neuron: first, it generates and shapes the action potential. Second, it separates the cell body from the axon, preserving the molecular identity of each compartment. In addition to a diffusion barrier restricting membrane proteins and lipids exchange, an intracellular filter has been proposed that could selectively exclude somatodendritic vesicles and recruit axonal cargoes. Finally, the AIS scaffold is capable of morphological plasticity during development or in response to network activity. These changes directly impact the neuron excitability, allowing an adaptive and homeostatic response. These plastic electrogenic properties, as well as the regulation of protein transport to and from the axon, may have important implications in several neuropathological contexts where the AIS structure is altered. Fifty years after its first characterization, the AIS thus emerges as a nexus for both neuronal organization and physiology. PMID:26781833

  16. Effects of Growth Hormone Administration on Muscle Strength in Men over 50 Years Old

    PubMed Central

    Tavares, A. B. W.; Micmacher, E.; Biesek, S.; Assumpção, R.; Redorat, R.; Veloso, U.; Vaisman, M.; Farinatti, P. T. V.; Conceição, F.

    2013-01-01

    Growth hormone (GH) use has been speculated to improve physical capacity in subjects without GH deficiency (GHD) through stimulation of collagen synthesis in the tendon and skeletal muscle, which leads to better exercise training and increased muscle strength. In this context, the use of GH in healthy elderly should be an option for increasing muscle strength. Our aim was to evaluate the effect of GH therapy on muscle strength in healthy men over 50 years old. Fourteen healthy men aged 50–70 years were evaluated at baseline for body composition and muscle strength (evaluated by leg press and bench press exercises, which focus primarily on quadriceps—lower body part and pectoralis major—upper body part—muscles, resp.). Subjects were randomised into 2 groups: GH therapy (7 subjects) and placebo (7 subjects) and reevaluated after 6 months of therapy. Thirteen subjects completed the study (6 subjects in the placebo group and 7 subjects in the GH group). Subjects of both groups were not different at baseline. After 6 months of therapy, muscle strength in the bench press responsive muscles did not increase in both groups and showed a statistically significant increase in the leg press responsive muscles in the GH group. Our study demonstrated an increase in muscle strength in the lower body part after GH therapy in healthy men. This finding must be considered and tested in frail older populations, whose physical incapacity is primarily caused by proximal muscle weakness. The trial was registered with NCT01853566. PMID:24382963

  17. Physiological status of broiler chicks at pulling time and the relationship to duration of holding period.

    PubMed

    Tong, Q; Demmers, T; Romanini, C E B; Bergoug, H; Roulston, N; Exadaktylos, V; Bahr, C; Berckmans, D; Guinebretière, M; Eterradossi, N; Garain, P; McGonnell, I M

    2015-07-01

    Newly hatched chicks may be held longer than 48 h and experience long periods of fasting in commercial hatcheries. Limited information is known about the physiological status of chicks in such situations, due to the difficulty of precisely recording time of hatch. This study investigated the effect of the time from hatch to pulling (holding period) on physiological measures/parameters in 109 broiler chicks. Fertile Ross 308 eggs were incubated in a custom built small-scale incubator. The individual hatching time of each focal chick was determined using eggshell temperature monitoring. At 'pulling' (512 h of incubation time), the quality of focal chicks was assessed using the chick scoring method and physiological parameters were measured including BW, organ (heart, liver and stomach) weights, blood values and plasma corticosterone level. The time from hatch to pulling varied from 7.58 to 44.97 h. Egg weight at setting was significantly correlated with chick BW and weight of organs at pulling, but had no effect on chick quality, blood values and plasma corticosterone. Relative BW at pulling was negatively associated with the duration of holding period (P=0.002). However, there was a positive correlation between relative stomach weight and the duration of the holding period (P<0.001). As the holding period duration increased, there was a trend that blood partial pressure of oxygen, haematocrit and haemoglobin also increased, and blood partial pressure of carbon dioxide, total carbon dioxide and bicarbonate decreased (P<0.05). A wide range of plasma corticosterone was observed from chicks that had experienced different durations of holding period. We conclude that shortening the hatch window and minimising the number of chicks that experience a long holding period before pulling may improve chick quality and physiological status, which may be due to unfavourable environmental conditions that include feed and water deprivation. PMID:25711527

  18. Plan form changes of Gumara River channel over 50 years (Upper Blue Nile basin, Ethiopia)

    NASA Astrophysics Data System (ADS)

    Abate, Mengiste; Nyssen, Jan; Mehari, Michael

    2014-05-01

    Channel plan form changes were investigated along the 65 km long Gumara River in Lake Tana basin (Ethiopia) by overlaying information from aerial photographs and SPOT imagery. Two sets of aerial photographs (1957 and 1980) were scanned, and then orthorectified in ENVI 4.2 environment. Recent channel plan form information was extracted from SPOT images of 2006. ERDAS 2010 and ArcGIS 10.1 tools were used for the data preparation and analysis. The information on river plan form changes spans from 1957 to 2006 (49 years), during which time the Gumara catchment has been subjected to changes in land use/cover and increasing water abstraction, which may have affected its hydrogeomorphology. The results indicated that the lower reach of Gumara at its mouth has undergone major plan form changes. A delta of 1.12 km² was created between 1957 and 1980 and additional 1.00 km² land has been created between 1980 and 2006. The sinuosity of the plan form changed only slightly through the study period: 1.78 in 1957, 1.76 in 1980, and 1.81 in 2006. Comparison of cross sections at the hydrological gauging station showed that the river bed aggraded in the order of 1.5 m to 2.5 m for the period 1963-2009. The trend analysis of stream flow of Gumara River versus rainfall in the catchment also indicated that the bed level of the Gumara river at its gauging station has risen. From field observations, the impact of direct human interventions was identified. The building of artificial levees along the river banks has contributed to huge deposition in the river bed. At locations where intensive irrigation takes place in the floodplain, seepage water through the banks created river bank failure and modifications in plan form. The unstable segments of the river reach were identified and will be further analysed.

  19. 50 years a biomedical engineer remembering a long and fascinating journey

    PubMed Central

    2012-01-01

    Looking back at one point of life appears as a nice exercise to round out and summarize. However, the objective should not be simply to tell a story; it must transmit a message to the young. To start with, two concepts are useful: Respect for others begins when you learn to laugh at yourself and, taken from an old saying, I did not want to be poor ... but money wouldn't make me rich. After elementary and high schools, during times of turmoil, I describe my engineering school years at the University of Buenos Aires and a working experience in an international telecommunications company. Significant events taught me a concept, rooted in another motto: Isn't this house nice? It is my house, and I love it very much. In 1960, I began my activities in the USA. A couple of bad decisions resulted in significant events for me teaching me an important truth: "Beware of golden promises; time is the most precious asset". Finally, in 1972, settled down in Tucumán until retirement in 2001, a long period of productive activity came about, not without difficulties and also stained by a dark political interval. Crises seem to characterize our generations in Argentina. Non-the-less, there were some real accomplishments: an undergraduate program in BME and a National BME Society (SABI) plus an archive of specialized published material. After spending time following retirement in Peru and Italy, my current activity came as unexpected dessert at the University of Buenos Aires, with a small research group, so offering the opportunity of transmitting what I still have available. PMID:22208504

  20. 50 years a biomedical engineer remembering a long and fascinating journey.

    PubMed

    Valentinuzzi, Max E

    2012-01-01

    Looking back at one point of life appears as a nice exercise to round out and summarize. However, the objective should not be simply to tell a story; it must transmit a message to the young. To start with, two concepts are useful: Respect for others begins when you learn to laugh at yourself and, taken from an old saying, I did not want to be poor ... but money wouldn't make me rich. After elementary and high schools, during times of turmoil, I describe my engineering school years at the University of Buenos Aires and a working experience in an international telecommunications company. Significant events taught me a concept, rooted in another motto: Isn't this house nice? It is my house, and I love it very much. In 1960, I began my activities in the USA. A couple of bad decisions resulted in significant events for me teaching me an important truth: "Beware of golden promises; time is the most precious asset". Finally, in 1972, settled down in Tucumán until retirement in 2001, a long period of productive activity came about, not without difficulties and also stained by a dark political interval. Crises seem to characterize our generations in Argentina. Non-the-less, there were some real accomplishments: an undergraduate program in BME and a National BME Society (SABI) plus an archive of specialized published material. After spending time following retirement in Peru and Italy, my current activity came as unexpected dessert at the University of Buenos Aires, with a small research group, so offering the opportunity of transmitting what I still have available. PMID:22208504

  1. A New Framework For Helicopter Vibration Suppression; Time-Periodic System Identification and Controller Design

    NASA Astrophysics Data System (ADS)

    Ulker, Fatma Demet

    In forward flight, helicopter rotor blades function within a highly complex aerodynamic environment that includes both near-blade and far-blade aerodynamic phenomena. These aerodynamic phenomena cause fluctuating aerodynamic loads on the rotor blades. These loads when coupled with the dynamic characteristics and elastic motion of the blade create excessive amount of vibration. These vibrations degrade helicopter performance, passenger comfort and contributes to high cost maintenance problems. In an effort to suppress helicopter vibration, recent studies have developed active control strategies using active pitch links, flaps, twist actuation and higher harmonic control of the swash plate. In active helicopter vibration control, designing a controller in a computationally efficient way requires accurate reduced-order models of complex helicopter aeroelasticity. In previous studies, controllers were designed using aeroelastic models that were obtained by coupling independently reduced aerodynamic and structural dynamic models. Unfortunately, these controllers could not satisfy stability and performance criteria when implemented in high-fidelity computer simulations or real-time experiments. In this thesis, we present a novel approach that provides accurate time-periodic reduced-order models and time-periodic H2 and H infinity controllers that satisfy the stability and performance criteria. Computational efficiency and the necessity of using the approach were validated by implementing an actively controlled flap strategy. In this proposed approach, the reduced-order models were directly identified from high-fidelity coupled aeroelastic analysis by using the time-periodic subspace identification method. Time-periodic H2 and Hinfinity controllers that update the control actuation at every time step were designed. The control synthesis problem was solved using Linear Matrix Inequality and periodic Riccati Equation based formulations, for which an in-house periodic

  2. Identification of periods of clear sky irradiance in time series of GHI measurements

    DOE PAGESBeta

    Reno, Matthew J.; Hansen, Clifford W.

    2016-01-18

    In this study, we present a simple algorithm for identifying periods of time with broadband global horizontal irradiance (GHI) similar to that occurring during clear sky conditions from a time series of GHI measurements. Other available methods to identify these periods do so by identifying periods with clear sky conditions using additional measurements, such as direct or diffuse irradiance. Our algorithm compares characteristics of the time series of measured GHI with the output of a clear sky model without requiring additional measurements. We validate our algorithm using data from several locations by comparing our results with those obtained from amore » clear sky detection algorithm, and with satellite and ground-based sky imagery.« less

  3. Periodic trim solutions with hp-version finite elements in time

    NASA Technical Reports Server (NTRS)

    Peters, David A.; Hou, Lin-Jun

    1990-01-01

    Finite elements in time as an alternative strategy for rotorcraft trim problems are studied. The research treats linear flap and linearized flap-lag response both for quasi-trim and trim cases. The connection between Fourier series analysis and hp-finite elements for periodic a problem is also examined. It is proved that Fourier series is a special case of space-time finite elements in which one element is used with a strong displacement formulation. Comparisons are made with respect to accuracy among Fourier analysis, displacement methods, and mixed methods over a variety parameters. The hp trade-off is studied for the periodic trim problem to provide an optimum step size and order of polynomial for a given error criteria. It is found that finite elements in time can outperform Fourier analysis for periodic problems, and for some given error criteria. The mixed method provides better results than does the displacement method.

  4. People's preference patterns for gains/losses in multiple time period situations.

    PubMed

    Chang, Shin-Shin; Chang, Jung-Hua

    2013-10-01

    Little research to date has been devoted to investigating whether people treat time differently from money when facing multiple gains or losses. This study tested the hypothesis that because time is characterized by perishability, fixed supply, and infungibility, people with strong motivation to obtain a long period of uninterrupted discretionary time would strive to trim the time needed for non-discretionary activities or to combine several non-discretionary activities. As a result, people prefer integration over segregation of multiple time losses or gains, which is not consistent with the prediction based on hedonic editing theory or the renewable resource model. This proposition is supported by results from four experiments. PMID:24597454

  5. The political economy of maize production and poverty reduction in Zambia: analysis of the last 50 years.

    PubMed

    Hanjra, Munir A; Culas, Richard J

    2011-01-01

    Poverty and food security are endemic issues in much of sub-Saharan Africa. To eradicate extreme poverty and hunger in the region remains a key Millennium Development Goal. Many African governments have pursued economic reforms and agricultural policy interventions in order to accelerate economic growth that reduces poverty faster. Agricultural policy regimes in Zambia in the last 50 years (1964–2008) are examined here to better understand their likely impact on food security and poverty, with an emphasis on the political economy of maize subsidy policies. The empirical work draws on secondary sources and an evaluation of farm household data from three villages in the Kasama District of Zambia from 1986/87 and 1992/93 to estimate a two-period econometric model to examine the impact on household welfare in a pre- and post-reform period. The analysis shows that past interventions had mixed effects on enhancing the production of food crops such as maize. While such reforms were politically popular, it did not necessarily translate into household-level productivity or welfare gains in the short term. The political economy of reforms needs to respond to the inherent diversity among the poor rural and urban households. The potential of agriculture to generate a more pro-poor growth process depends on the creation of new market opportunities that most benefit the rural poor. The state should encourage private sector investments for addressing infrastructure constraints to improve market access and accelerate more pro-poor growth through renewed investments in agriculture, rural infrastructure, gender inclusion, smarter subsidies and regional food trade. However, the financing of such investments poses significant challenges. There is a need to address impediments to the effective participation of public private investors to generate more effective poverty reduction and hunger eradication programmes. This article also explores the opportunities for new public

  6. Adaptive time-delayed stabilization of steady states and periodic orbits.

    PubMed

    Selivanov, Anton; Lehnert, Judith; Fradkov, Alexander; Schöll, Eckehard

    2015-01-01

    We derive adaptive time-delayed feedback controllers that stabilize fixed points and periodic orbits. First, we develop an adaptive controller for stabilization of a steady state by applying the speed-gradient method to an appropriate goal function and prove global asymptotic stability of the resulting system. For an example we show that the advantage of the adaptive controller over the nonadaptive one is in a smaller controller gain. Second, we propose adaptive time-delayed algorithms for stabilization of periodic orbits. Their efficiency is confirmed by local stability analysis. Numerical examples demonstrate the applicability of the proposed controllers. PMID:25679681

  7. A Time-Delayed Mathematical Model for Tumor Growth with the Effect of a Periodic Therapy

    PubMed Central

    Xu, Shihe; Wei, Xiangqing; Zhang, Fangwei

    2016-01-01

    A time-delayed mathematical model for tumor growth with the effect of periodic therapy is studied. The establishment of the model is based on the reaction-diffusion dynamics and mass conservation law and is considered with a time delay in cell proliferation process. Sufficient conditions for the global stability of tumor free equilibrium are given. We also prove that if external concentration of nutrients is large the tumor will not disappear and the conditions under which there exist periodic solutions to the model are also determined. Results are illustrated by computer simulations. PMID:27274763

  8. Adaptive time-delayed stabilization of steady states and periodic orbits

    NASA Astrophysics Data System (ADS)

    Selivanov, Anton; Lehnert, Judith; Fradkov, Alexander; Schöll, Eckehard

    2015-01-01

    We derive adaptive time-delayed feedback controllers that stabilize fixed points and periodic orbits. First, we develop an adaptive controller for stabilization of a steady state by applying the speed-gradient method to an appropriate goal function and prove global asymptotic stability of the resulting system. For an example we show that the advantage of the adaptive controller over the nonadaptive one is in a smaller controller gain. Second, we propose adaptive time-delayed algorithms for stabilization of periodic orbits. Their efficiency is confirmed by local stability analysis. Numerical examples demonstrate the applicability of the proposed controllers.

  9. A Time-Delayed Mathematical Model for Tumor Growth with the Effect of a Periodic Therapy.

    PubMed

    Xu, Shihe; Wei, Xiangqing; Zhang, Fangwei

    2016-01-01

    A time-delayed mathematical model for tumor growth with the effect of periodic therapy is studied. The establishment of the model is based on the reaction-diffusion dynamics and mass conservation law and is considered with a time delay in cell proliferation process. Sufficient conditions for the global stability of tumor free equilibrium are given. We also prove that if external concentration of nutrients is large the tumor will not disappear and the conditions under which there exist periodic solutions to the model are also determined. Results are illustrated by computer simulations. PMID:27274763

  10. Developmental critical windows and sensitive periods as three-dimensional constructs in time and space.

    PubMed

    Burggren, Warren W; Mueller, Casey A

    2015-01-01

    A critical window (sensitive period) represents a period during development when an organism's phenotype is responsive to intrinsic or extrinsic (environmental) factors. Such windows represent a form of developmental phenotypic plasticity and result from the interaction between genotype and environment. Critical windows have typically been defined as comprising discrete periods in development with a distinct starting time and end time, as identified by experiments following an on and an off protocol. Yet in reality, periods of responsiveness during development are likely more ambiguous that depicted. Our goal is to extend the concept of the developmental critical window by introducing a three-dimensional construct in which time during development, dose of the stressor applied, and the resultant phenotypic modification can be utilized to more realistically define a critical window. Using the example of survival of the brine shrimp (Artemia franciscana) during exposure to different salinity levels during development, we illustrate that it is not just stressor dose or exposure time but the interaction of these two factors that results in the measured phenotypic change, which itself may vary within a critical window. We additionally discuss a systems approach to critical windows, in which the components of a developing system--whether they be molecular, physiological, or morphological--may show differing responses with respect to time and dose. Thus, the plasticity of each component may contribute to a broader overall system response. PMID:25730265

  11. [50 years of total hip prosthesis--a tribute to Prof. Sir John Charnley].

    PubMed

    Mikić, Zelimir Dj; Lesić, Aleksandar R

    2013-01-01

    November 2012 marked the 50th anniversary of the first implantation of a successful and long-lived hip endoprosthesis, which was performed by Prof Sir John Charnley in the "Centre for Hip Surgery" at a small country place in the north-west England. John Charnley (1911-1982) finished medical school at the Victoria University of Manchester in 1935, and than started training in orthopaedics at the Manchester Royal Infirmary, and completed it after the Second World War, in which he served as a volunteer. After that he continued working in the same hospital, and, apart from that he worked as a lecturer at the University of Manchester, and from 1949 as a visiting surgeon in the Wrightington Hospital. In 1958 Charnley decided to put his efforts into the development of hip replacement research and surgery, and initiated the foundation of the "Centre for Hip Surgery" with Biomechanical laboratory in the Wrightington Hospital in 1960, where the intesive basic and clinical research started, and becuase of that Charnley in 1962 left Manchester and moved with a full time practice at the Wrightington Hospital. That period of research time was not easy, there were many "trial and tribulations", but, owing to the tenacity and inventive mind of Charnley, in 1962 a new prosthesis consisting of a cemented metal stem with a 22 mm head articulating with a cemented polyethilene acetabular component, and with a low frictional torque was designed. The first such prosthesis, which later produced excellent long-term results, was implanted on November 22nd, 1962, and today, when we look back over a distance of fifty years, we can conclude that that day could be considered as a beginning of a modem aloarthroplastic surgery, and certainly as one of the greatest orthopaedic advance in the whole of the 20th century; and all that was initiated and promoted by Prof. Sir John Charnley. PMID:24669557

  12. Spatiotemporal variations of precipitation extremes of China during the past 50 years (1960-2009)

    NASA Astrophysics Data System (ADS)

    Chi, Xiaoxiao; Yin, Zhan'e.; Wang, Xuan; Sun, Yuke

    2016-05-01

    Extreme weather events have become more frequent and intense under global warming in recent years, which has attracted much attention of scholars at home and abroad. In this paper, we used data sets of daily precipitation recorded at 499 meteorological stations to analyze the temporal and spatial variations of precipitation extremes in China over the past 50 years (1960-2009). Through the comparison of detrended fluctuation analysis (DFA) and the percentile method, DFA was selected to define the thresholds of precipitation extremes in China. Temporal variations of extreme precipitation amount, frequency, and intensity were analyzed in four major regions: Northwest China, the Qinghai-Tibet region, North China, and South China. Spatial distributions were obtained by the Kriging interpolation method, and then, we examined the varying tendencies of extreme precipitation amount, frequency, and intensity by the Mann-Kendall test. The results show that increasing trends are dominant for all indices over China; extreme precipitation amount and frequency appear to have risen since 1970-1979, but there are some regional differences. The Qinghai-Tibet region and South China have an ascending trend, and Northwest China maintains balance while North China has a descending trend. The amount and intensity of precipitation extremes are decreasing from southeastern coastal areas to northwestern inlands, and the frequency of precipitation extremes is randomly distributed. However, they are all high in the Sichuan Basin, the middle and lower Yangtze River, and the southern part of South China. Trends of most stations are statistically insignificant, but the percentage of stations with a significant increased trend in the Qinghai-Tibet region is larger than that of other regions.

  13. 50 years of DNA ‘Breathing’: Reflections on Old and New Approaches

    PubMed Central

    von Hippel, Peter H.; Johnson, Neil P.; Marcus, Andrew H.

    2015-01-01

    Summary The coding sequences for genes, and much other regulatory information involved in genome expression, are located ‘inside’ the DNA duplex. Thus the ‘macromolecular machines’ that read-out this information from the base sequence of the DNA must somehow access the DNA ‘interior’. Double-stranded (ds) DNA is a highly structured and cooperatively stabilized system at physiological temperatures, but is also only marginally stable and undergoes a cooperative ‘melting phase transition’ at temperatures not far above physiological. Furthermore, due to its length and heterogeneous sequence, with AT-rich segments being less stable than GC-rich segments, the DNA genome ‘melts’ in a multistate fashion. Therefore the DNA genome must also manifest thermally driven structural (‘breathing’) fluctuations at physiological temperatures that should reflect the heterogeneity of the dsDNA stability near the melting temperature. Thus many of the breathing fluctuations of dsDNA are likely also to be sequence dependent, and could well contain information that should be ‘readable’ and useable by regulatory proteins and protein complexes in site-specific binding reactions involving dsDNA ‘opening’. Our laboratory has been involved in studying the breathing fluctuations of duplex DNA for about 50 years. In this ‘Reflections’ article we present a relatively chronological overview of these studies, starting with the use of simple chemical probes (such as hydrogen exchange, formaldehyde and simple DNA ‘melting’ proteins) to examine the local stability of the dsDNA structure, and culminating in sophisticated spectroscopic approaches that can be used to monitor the breathing-dependent interactions of regulatory complexes with their duplex DNA targets in ‘real time’. PMID:23840028

  14. The Charles F. Prentice Award Lecture 2014: A 50-Year Research Journey: Giants and Great Collaborators.

    PubMed

    Holden, Brien A

    2015-07-01

    This article, an edited version of the 2014 Charles F. Prentice Medal presentation, recounts my 50-year journey in research, from graduation in 1965 to PhD to 2015. The most important lessons I have learned are that great people, "Giants" as I call them, are generous of spirit, creative, insightful, sharing, and caring, and second, that collaboration is really the only way to do what I want to get done. I have been very fortunate to have worked with many outstanding people. As someone said to me at the Prentice Medal presentation, "I don't like you very much but the people you work with are wonderful."My journey started with a PhD investigation into seeing if orthokeratology could control myopia at the City University London in 1966. It then moved to Australia where all aspects of contact lenses were researched to try to make contact lenses safer and more effective by understanding the cornea and anterior eye systems. That journey has now turned to making contact lenses the best they can be to slow the progress of myopia. An extremely high proportion of people who are involved with global eye care initiatives and ambitious projects to develop treatments and interventions for the major vision problems impacting the world are a joy to work with. Evidence-based systems for delivering vision to the more than 600 million people globally that are blind or vision impaired because of uncorrected refractive error have involved amazing people and collaborations. This article pays tribute to the generosity and humanity of my family and the Giants in and outside the field, and many more not so well known, and the people I work with, who have punctuated and greatly enriched this journey and made many of the scientific advances documented here possible. PMID:26002010

  15. Age at Menarche: 50-Year Socioeconomic Trends Among US-Born Black and White Women

    PubMed Central

    Kiang, Mathew V.; Kosheleva, Anna; Waterman, Pamela D.; Chen, Jarvis T.; Beckfield, Jason

    2015-01-01

    Objectives. We investigated 50-year US trends in age at menarche by socioeconomic position (SEP) and race/ethnicity because data are scant and contradictory. Methods. We analyzed data by income and education for US-born non-Hispanic Black and White women aged 25 to 74 years in the National Health Examination Survey (NHES) I (1959–1962), National Health Examination and Nutrition Surveys (NHANES) I–III (1971–1994), and NHANES 1999–2008. Results. In NHES I, average age at menarche among White women in the 20th (lowest) versus 80th (highest) income percentiles was 0.26 years higher (95% confidence interval [CI] = −0.09, 0.61), but by NHANES 2005–2008 it had reversed and was −0.33 years lower (95% CI = −0.54, −0.11); no socioeconomic gradients occurred among Black women. The proportion with onset at younger than 11 years increased only among women with low SEP, among Blacks and Whites (P for trend < .05), and high rates of change occurred solely among Black women (all SEP strata) and low-income White women who underwent menarche before 1960. Conclusions. Trends in US age at menarche vary by SEP and race/ethnicity in ways that pose challenges to several leading clinical, public health, and social explanations for early age at menarche and that underscore why analyses must jointly include data on race/ethnicity and socioeconomic position. Future research is needed to explain these trends. PMID:25033121

  16. Neighbourhood socioeconomic status and coronary heart disease in individuals between 40 and 50 years

    PubMed Central

    Carlsson, Axel C; Li, Xinjun; Holzmann, Martin J; Wändell, Per; Gasevic, Danijela; Sundquist, Jan; Sundquist, Kristina

    2016-01-01

    Objective The incidence of myocardial infarction (MI) has decreased in general but not among younger middle-aged adults. We performed a cohort study of the association between neighbourhood socioeconomic status (SES) at the age of 40 and risk of MI before the age of 50 years. Methods All individuals in Sweden were included in the year of their 40th birthday, if it occurred between 1998 and 2010. National registers were used to categorise neighbourhood SES into high, middle and low, and to retrieve information on incident MI and coronary heart disease (CHD). Cox regression models, adjusted for marital status, education level, immigrant status and region of residence, provided an estimate of the HRs and 95% CIs for MI or CHD. Results Out of 587 933 men and 563 719 women, incident MI occurred in 2877 (0.48%) men and 932 (0.17%) women; and CHD occurred in 4400 (0.74%) men and 1756 (0.31%) women during a mean follow-up of 5.5 years. Using individuals living in middle-SES neighbourhoods as referents, living in high-SES neighbourhoods was associated with lower risk of MI in both sexes (HR (95% CI): men: 0.72 (0.64 to 0.82), women: 0.66 (0.53 to 0.81)); living in low-SES neighbourhoods was associated with a higher risk of MI (HR (95% CI): men: 1.31 (1.20 to 1.44), women: 1.28 (1.08 to 1.50)). Similar risk estimates for CHD were found. Conclusions The results of our study suggest an increased risk of MI and CHD among residents from low-SES neighbourhoods and a lower risk in those from high-SES neighbourhoods compared with residents in middle-SES neighbourhoods. PMID:26864672

  17. Modeling laser-induced periodic surface structures: Finite-difference time-domain feedback simulations

    SciTech Connect

    Skolski, J. Z. P. Vincenc Obona, J.; Römer, G. R. B. E.; Huis in 't Veld, A. J.

    2014-03-14

    A model predicting the formation of laser-induced periodic surface structures (LIPSSs) is presented. That is, the finite-difference time domain method is used to study the interaction of electromagnetic fields with rough surfaces. In this approach, the rough surface is modified by “ablation after each laser pulse,” according to the absorbed energy profile, in order to account for inter-pulse feedback mechanisms. LIPSSs with a periodicity significantly smaller than the laser wavelength are found to “grow” either parallel or orthogonal to the laser polarization. The change in orientation and periodicity follow from the model. LIPSSs with a periodicity larger than the wavelength of the laser radiation and complex superimposed LIPSS patterns are also predicted by the model.

  18. Natural convection in an enclosure under time periodic heating: An experimental study

    SciTech Connect

    Antohe, B.V.; Lage, J.L.

    1996-12-31

    The effect of the heating period on the heat transfer across a water filled rectangular enclosure is examined experimentally. The enclosure is designed such that periodic heat by Joule effect is delivered at one wall while the opposite wall is maintained at an approximately constant temperature. All other surfaces are insulated. Several heating power levels are chosen with equivalent time averaged heat-flux based Rayleigh number varying from 2.5 {times} 10{sup 8} to 1.0 {times} 10{sup 9}. The heating period varies from 32 seconds to 1600 seconds. For the highest Rayleigh number, Ra = 1.0 {times} 10{sup 9}, the oscillatory heating process leads to a cycle averaged heat transfer coefficient 20 percent higher than obtained with steady averaged-heat flux heating. Results, presented in terms of temperature time series, phase-plane portrait, and time evolution of cooling and heating wall temperatures, indicate that for low heating frequencies the heat transfer across the enclosure is hindered, with the time averaged heat transfer coefficient decreasing by as much as 13 percent of the equivalent steady heating value. A plausible explanation for the phenomenon is offered and discussed. The instantaneous and cycle averaged heat transfer coefficients, and the corresponding Nusselt numbers, are also presented for various heating frequencies.

  19. Relaxation Time of Artificial Periodic Irregularities of the Ionospheric Plasma and Diffusion in the Inhomogeneous Atmosphere

    NASA Astrophysics Data System (ADS)

    Grigor'ev, G. I.; Bakhmet'eva, N. V.; Tolmacheva, A. V.; Kalinina, E. E.

    2013-09-01

    We consider diffusion of the ionospheric-plasma irregularities as applied to the problem of experimental determination of the lower-ionosphere parameters by artificial periodic irregularities of the electron number density. A rigorous solution to the problem of diffusion of one-dimensional plasma irregularities in a weakly ionized medium, whose diffusion coefficient exponentially decreases with the altitude, is obtained. The Green's function for this problem is found. Three parameters are taken into account in the solution, namely, the size of the region occupied by the irregularities, the size of the irregularities, and a typical spatial scale of the e-fold decrease in the diffusion coefficient. Theoretical relaxation times of the irregularities as functions of these parameters are analyzed. Calculated relaxation times are compared with the times measured in the observation of the artificial periodic irregularities created by the SURA facility. Calculated relaxation times of these irregularities are in good agreement with the observed values.

  20. A Gaussian Process Based Online Change Detection Algorithm for Monitoring Periodic Time Series

    SciTech Connect

    Chandola, Varun; Vatsavai, Raju

    2011-01-01

    Online time series change detection is a critical component of many monitoring systems, such as space and air-borne remote sensing instruments, cardiac monitors, and network traffic profilers, which continuously analyze observations recorded by sensors. Data collected by such sensors typically has a periodic (seasonal) component. Most existing time series change detection methods are not directly applicable to handle such data, either because they are not designed to handle periodic time series or because they cannot operate in an online mode. We propose an online change detection algorithm which can handle periodic time series. The algorithm uses a Gaussian process based non-parametric time series prediction model and monitors the difference between the predictions and actual observations within a statistically principled control chart framework to identify changes. A key challenge in using Gaussian process in an online mode is the need to solve a large system of equations involving the associated covariance matrix which grows with every time step. The proposed algorithm exploits the special structure of the covariance matrix and can analyze a time series of length T in O(T^2) time while maintaining a O(T) memory footprint, compared to O(T^4) time and O(T^2) memory requirement of standard matrix manipulation methods. We experimentally demonstrate the superiority of the proposed algorithm over several existing time series change detection algorithms on a set of synthetic and real time series. Finally, we illustrate the effectiveness of the proposed algorithm for identifying land use land cover changes using Normalized Difference Vegetation Index (NDVI) data collected for an agricultural region in Iowa state, USA. Our algorithm is able to detect different types of changes in a NDVI validation data set (with ~80% accuracy) which occur due to crop type changes as well as disruptive changes (e.g., natural disasters).

  1. Thinking inside the Block Schedule: Strategies for Teaching in Extended Periods of Time.

    ERIC Educational Resources Information Center

    Robbins, Pam; Gregory, Gayle; Herndon, Lynne E.

    This book provides an array of strategies that can help teachers, administrators, and staff-development personnel as they plan, develop, and deliver content within extended periods of instructional time. It emphasizes the importance of teachers and administrators working together to improve instruction and contends that staff development remains…

  2. 20 CFR 261.10 - Increase in future benefits where time period for reopening has expired.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Increase in future benefits where time period for reopening has expired. 261.10 Section 261.10 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT ADMINISTRATIVE FINALITY § 261.10 Increase in future...

  3. 9 CFR 201.217 - Reasonable period of time to remedy a breach of contract.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Reasonable period of time to remedy a breach of contract. 201.217 Section 201.217 Animals and Animal Products GRAIN INSPECTION, PACKERS AND... contract or agreement where food safety or animal welfare is concerned. These criteria, include, but...

  4. 9 CFR 201.217 - Reasonable period of time to remedy a breach of contract.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Reasonable period of time to remedy a breach of contract. 201.217 Section 201.217 Animals and Animal Products GRAIN INSPECTION, PACKERS AND... contract or agreement where food safety or animal welfare is concerned. These criteria, include, but...

  5. 9 CFR 201.217 - Reasonable period of time to remedy a breach of contract.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Reasonable period of time to remedy a breach of contract. 201.217 Section 201.217 Animals and Animal Products GRAIN INSPECTION, PACKERS AND... contract or agreement where food safety or animal welfare is concerned. These criteria, include, but...

  6. The Role of Thermal Properties in Periodic Time-Varying Phenomena

    ERIC Educational Resources Information Center

    Marin, E.

    2007-01-01

    The role played by physical parameters governing the transport of heat in periodical time-varying phenomena within solids is discussed. Starting with a brief look at the conduction heat transport mechanism, the equations governing heat conduction under static, stationary and non-stationary conditions, and the physical parameters involved, are…

  7. Asymptotic bounds for the time-periodic solutions to the singularly perturbed ordinary differential equations.

    PubMed

    Amiraliyev, Gabil M; Ucar, Aysenur

    2013-01-01

    The periodical in time problem for singularly perturbed second order linear ordinary differential equation is considered. The boundary layer behavior of the solution and its first and second derivatives have been established. An example supporting the theoretical analysis is presented. PMID:24369452

  8. Forum Page Letters in the "Straits Times" of Singapore during Relatively Free and Restricted Press Periods.

    ERIC Educational Resources Information Center

    Ramaprasad, Jyotika; Ong, James

    In order to identify the scope or limits of the practice of development journalism, a study examined the content of the Forum page in the "Straits Times" of Singapore during relatively free (1979-1980) and restricted (1986-1987) press periods. The study had two major objectives: (1) to study the nature of the Forum page (a readers' letter page in…

  9. 41 CFR 105-8.150-3 - Time period for compliance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false Time period for compliance. 105-8.150-3 Section 105-8.150-3 Public Contracts and Property Management Federal Property Management Regulations System (Continued) GENERAL SERVICES ADMINISTRATION 8-ENFORCEMENT OF...

  10. 41 CFR 105-8.150-3 - Time period for compliance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Time period for compliance. 105-8.150-3 Section 105-8.150-3 Public Contracts and Property Management Federal Property Management Regulations System (Continued) GENERAL SERVICES ADMINISTRATION 8-ENFORCEMENT OF...

  11. 41 CFR 105-8.150-3 - Time period for compliance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Time period for compliance. 105-8.150-3 Section 105-8.150-3 Public Contracts and Property Management Federal Property Management Regulations System (Continued) GENERAL SERVICES ADMINISTRATION 8-ENFORCEMENT OF...

  12. 41 CFR 105-8.150-3 - Time period for compliance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false Time period for compliance. 105-8.150-3 Section 105-8.150-3 Public Contracts and Property Management Federal Property Management Regulations System (Continued) GENERAL SERVICES ADMINISTRATION 8-ENFORCEMENT OF...

  13. 20 CFR 261.10 - Increase in future benefits where time period for reopening has expired.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Increase in future benefits where time period for reopening has expired. 261.10 Section 261.10 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT ADMINISTRATIVE FINALITY § 261.10 Increase in future...

  14. Determination of the Conservation Time of Periodicals for Optimal Shelf Maintenance of a Library.

    ERIC Educational Resources Information Center

    Miyamoto, Sadaaki; Nakayama, Kazuhiko

    1981-01-01

    Presents a method based on a constrained optimization technique that determines the time of removal of scientific periodicals from the shelf of a library. A geometrical interpretation of the theoretical result is given, and a numerical example illustrates how the technique is applicable to real bibliographic data. (FM)

  15. 45 CFR 96.14 - Time period for obligation and expenditure of grant funds.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 1 2011-10-01 2011-10-01 false Time period for obligation and expenditure of grant funds. 96.14 Section 96.14 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL... first allotted shall remain available for obligation during the succeeding fiscal year for all...

  16. 45 CFR 96.14 - Time period for obligation and expenditure of grant funds.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Time period for obligation and expenditure of grant funds. 96.14 Section 96.14 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL... first allotted shall remain available for obligation during the succeeding fiscal year for all...

  17. 42 CFR 87.7 - For what period of time will grants be awarded?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false For what period of time will grants be awarded? 87.7 Section 87.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY...

  18. 42 CFR 87.7 - For what period of time will grants be awarded?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false For what period of time will grants be awarded? 87.7 Section 87.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY...

  19. Identifying the Critical Time Period for Information Extraction when Recognizing Sequences of Play

    ERIC Educational Resources Information Center

    North, Jamie S.; Williams, A. Mark

    2008-01-01

    The authors attempted to determine the critical time period for information extraction when recognizing play sequences in soccer. Although efforts have been made to identify the perceptual information underpinning such decisions, no researchers have attempted to determine "when" this information may be extracted from the display. The authors…

  20. 45 CFR 96.14 - Time period for obligation and expenditure of grant funds.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 1 2012-10-01 2012-10-01 false Time period for obligation and expenditure of grant funds. 96.14 Section 96.14 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL... first allotted shall remain available for obligation during the succeeding fiscal year for all...

  1. A Comparison of Terminally Ill Persons at Various Time Periods to Death.

    ERIC Educational Resources Information Center

    Baugher, Robert J.; And Others

    1990-01-01

    Examined responses of 1,110 terminally ill persons with cancer at varying time periods prior to death. Disengagement and Objective Self-Awareness theories, which suggest that people nearing death would increase desire to separate from others, were not supported. Found few differences in responses of persons further from, or closer to, death.…

  2. 42 CFR 87.7 - For what period of time will grants be awarded?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY AND... awards will be of such factors as the grantee's progress and management practices, and the availability... 42 Public Health 1 2011-10-01 2011-10-01 false For what period of time will grants be awarded?...

  3. Practitioners' Perceptions of the Soccer Extra-Time Period: Implications for Future Research.

    PubMed

    Harper, Liam D; Fothergill, Melissa; West, Daniel J; Stevenson, Emma; Russell, Mark

    2016-01-01

    Qualitative research investigating soccer practitioners' perceptions can allow researchers to create practical research investigations. The extra-time period of soccer is understudied compared to other areas of soccer research. Using an open-ended online survey containing eleven main and nine sub questions, we gathered the perceptions of extra-time from 46 soccer practitioners, all working for different professional soccer clubs. Questions related to current practices, views on extra-time regulations, and ideas for future research. Using inductive content analysis, the following general dimensions were identified: 'importance of extra-time', 'rule changes', 'efficacy of extra-time hydro-nutritional provision', 'nutritional timing', 'future research directions', 'preparatory modulations' and 'recovery'. The majority of practitioners (63%) either agreed or strongly agreed that extra-time is an important period for determining success in knockout football match-play. When asked if a fourth substitution should be permitted in extra-time, 67% agreed. The use of hydro-nutritional strategies prior to extra-time was predominately considered important or very important. However; only 41% of practitioners felt that it was the most important time point for the use of nutritional products. A similar number of practitioners account (50%) and do not (50%) account for the potential of extra-time when training and preparing players and 89% of practitioners stated that extra-time influences recovery practices following matches. In the five minute break prior to extra-time, the following practices (in order of priority) were advocated to players: hydration, energy provision, massage, and tactical preparations. Additionally, 87% of practitioners advocate a particular nutritional supplementation strategy prior to extra-time. In order of importance, practitioners see the following as future research areas: nutritional interventions, fatigue responses, acute injury risk, recovery

  4. Mid-to long-term results of revision total hip replacement in patients aged 50 years or younger.

    PubMed

    Lee, P T H; Lakstein, D L; Lozano, B; Safir, O; Backstein, J; Gross, A E

    2014-08-01

    Revision total hip replacement (THR) for young patients is challenging because of technical complexity and the potential need for subsequent further revisions. We have assessed the survivorship, functional outcome and complications of this procedure in patients aged < 50 years through a large longitudinal series with consistent treatment algorithms. Of 132 consecutive patients (181 hips) who underwent revision THR, 102 patients (151 hips) with a mean age of 43 years (22 to 50) were reviewed at a mean follow-up of 11 years (2 to 26) post-operatively. We attempted to restore bone stock with allograft where indicated. Using further revision for any reason as an end point, the survival of the acetabular component was 71% (sd 4) and 54% (sd 7) at ten- and 20 years. The survival of the femoral component was 80% (sd 4) and 62% (sd 6) at ten- and 20 years. Complications included 11 dislocations (6.1%), ten periprosthetic fractures (5.5%), two deep infections (1.1%), four sciatic nerve palsies (2.2%; three resolved without intervention, one improved after exploration and freeing from adhesions) and one vascular injury (0.6%). The mean modified Harris Hip Score was 41 (10 to 82) pre-operatively, 77 (39 to 93) one year post-operatively and 77 (38 to 93) at the latest review. This overall perspective on the mid- to long-term results is valuable when advising young patients on the prospects of revision surgery at the time of primary replacement. PMID:25086120

  5. Nematode diversity, abundance and community structure 50 years after the formation of the volcanic island of Surtsey

    NASA Astrophysics Data System (ADS)

    Ilieva-Makulec, K.; Bjarnadottir, B.; Sigurdsson, B. D.

    2014-10-01

    The soil nematode fauna can give important insights into soil development and other habitat changes that occur during primary succession. We investigated the generic composition, density, distribution and community structure of nematodes 50 years after the formation of a pristine volcanic island, Surtsey, Iceland. Part of the island has received additional nutrient inputs from seagulls breeding there since 1985, while the reminder has been much less affected and is at present found at a different successional sere. In total, 25 genera of nematodes were identified, of which 14 were reported on Surtsey for the first time. Nematode communities were more diverse in the more infertile area outside the gull colony, where 24 genera were found, compared to 18 inside. The trophic structure of the nematode communities showed relatively higher abundance of fungal feeders in the infertile areas, but relatively more bacterial- and plant-feeders inside the colony. Nematode abundance in surface soil was, however, significantly higher within the gull colony, with 16.7 ind. cm-2 compared to 3.6 ind. cm-2 outside. A multivariate analysis indicated that the nematode abundance and distribution on Surtsey were most strongly related to the soil C : N ratio, soil acidity, plant cover and biomass, soil temperature and soil depth.

  6. Time Periods of Unusual Density Behavior Observed by GRACE and CHAMP

    NASA Astrophysics Data System (ADS)

    McLaughlin, C. A.; Fattig, E.; Mysore Krishna, D.; Locke, T.; Mehta, P. M.

    2011-12-01

    Time periods of low cross correlation between precision orbit ephemeris (POE) derived density and accelerometer density for CHAMP and GRACE are examined. In particular, the cross correlation for GRACE dropped from typical values near 0.9 to much lower values and then returned to typical over the time period of late October to late December of 2005. This time period includes a maneuver where GRACE-A and GRACE-B swapped positions. However, the drop in cross correlation begins and reaches its low point before the maneuvers begin. In addition, the densities were found using GRACE-A, but GRACE-B did most of the maneuvering. The time period is characterized by high frequency variations in accelerometer density of the same magnitude as the daylight to eclipse variations over the course of an orbit. However, the daylight to eclipse variations are particularly small during this time period because the orbit plane is near the terminator. Additionally, the difference between the accelerometer and POE derived densities are not unusually large during this time period. This implies the variations are not unusual, just more significant when the orbit plane is near terminator. Cyclical variations in correlation of the POE derived densities with accelerometer derived densities are seen for both GRACE and CHAMP, but the magnitude of the variations are much larger for GRACE, possibly because of the higher altitude of GRACE. The cycles seem to be phased so that low correlations occur with low beta angle when the orbit plane is near the terminator. The low correlation is possibly caused by the lower amplitude of the daylight to eclipse signal making higher frequency variations relatively more important. However, another possible explanation is terminator waves in density that propagate to the thermosphere from lower in the atmosphere. These waves have been observed in CHAMP accelerometer data and global circulation model simulations. Further investigation is needed to see if the

  7. Determination of Optimum Period between Inspections for Distribution System based on Availability Accounting Uncertainties in Inspection Time and Repair Time

    NASA Astrophysics Data System (ADS)

    Tiwary, A.; Arya, R.; Choube, S. C.; Arya, L. D.

    2012-06-01

    This paper describes a technique for determination of optimum duration between inspections for each distributor segment of a distribution system. The optimum period between inspections is decided based on maximization of availability of the distribution system. The view point presented is that after inspection a minor maintenance is carried out which may otherwise cause failure of the system in future, for example, trimming of tree branches, arcing and damages of jumper connections and to avoid breakdown of insulators. Such stray causes may have small failure rates in total but periodic inspection and maintenance will increase the availability. Exponential failure law has been assumed. Inspection time and repair time, if required after inspection, have been assumed to be normally distributed. Two-membered evolution strategy has been used for optimization. The algorithm has been implemented on a sample radial distribution system.

  8. Reliability of Fitness Tests Using Methods and Time Periods Common in Sport and Occupational Management

    PubMed Central

    Burnstein, Bryan D.; Steele, Russell J.; Shrier, Ian

    2011-01-01

    Context: Fitness testing is used frequently in many areas of physical activity, but the reliability of these measurements under real-world, practical conditions is unknown. Objective: To evaluate the reliability of specific fitness tests using the methods and time periods used in the context of real-world sport and occupational management. Design: Cohort study. Setting: Eighteen different Cirque du Soleil shows. Patients or Other Participants: Cirque du Soleil physical performers who completed 4 consecutive tests (6-month intervals) and were free of injury or illness at each session (n = 238 of 701 physical performers). Intervention(s): Performers completed 6 fitness tests on each assessment date: dynamic balance, Harvard step test, handgrip, vertical jump, pull-ups, and 60-second jump test. Main Outcome Measure(s): We calculated the intraclass coefficient (ICC) and limits of agreement between baseline and each time point and the ICC over all 4 time points combined. Results: Reliability was acceptable (ICC > 0.6) over an 18-month time period for all pairwise comparisons and all time points together for the handgrip, vertical jump, and pull-up assessments. The Harvard step test and 60-second jump test had poor reliability (ICC < 0.6) between baseline and other time points. When we excluded the baseline data and calculated the ICC for 6-month, 12-month, and 18-month time points, both the Harvard step test and 60-second jump test demonstrated acceptable reliability. Dynamic balance was unreliable in all contexts. Limit-of-agreement analysis demonstrated considerable intraindividual variability for some tests and a learning effect by administrators on others. Conclusions: Five of the 6 tests in this battery had acceptable reliability over an 18-month time frame, but the values for certain individuals may vary considerably from time to time for some tests. Specific tests may require a learning period for administrators. PMID:22488138

  9. Comparison of weight loss outcomes 1 year after sleeve gastrectomy and Roux-en-Y gastric bypass in patients aged above 50 years

    PubMed Central

    Praveenraj, Palanivelu; Gomes, Rachel M; Kumar, Saravana; Perumal, Sivalingam; Senthilnathan, Palanisamy; Parthasarathi, Ramakrishnan; Rajapandian, Subbiah; Palanivelu, Chinnusamy

    2016-01-01

    INTRODUCTION: Safe, effective weight loss with resolution of comorbidities has been convincingly demonstrated with bariatric surgery in the aged obese. They, however, lose less weight than younger individuals. It is not known if degree of weight loss is influenced by the choice of bariatric procedure. The aim of this study was to compare the degree of weight loss between laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB) in patients above the age of 50 years at 1 year after surgery. MATERIALS AND METHODS: A retrospective analysis was performed of all patients more than 50 years of age who underwent LSG or LRYGB between February 2012 and July 2013 with at least 1 year of follow-up. Data evaluated at 1 year included age, sex, weight, body mass index (BMI), mean operative time, percentage of weight loss and excess weight loss, resolution/remission of diabetes, morbidity and mortality. RESULTS: Of a total of 86 patients, 54 underwent LSG and 32 underwent LRYGB. The mean percentage of excess weight loss at the end of 1 year was 60.19 ± 17.45 % after LSG and 82.76 ± 34.26 % after LRYGB (P = 0.021). One patient developed a sleeve leak after LSG, and 2 developed iron deficiency anaemia after LRYGB. The remission/improvement in diabetes mellitus and biochemistry was similar. CONCLUSION: LRYGB may offer better results than LSG in terms of weight loss in patients over 50 years of age. PMID:27279392

  10. Time-space Variability of Weekly to Monthly Period Equatorial Waves in the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Durland, T.; Farrar, J. T.

    2015-12-01

    Data from satellite altimetry are used to characterize wavelike variability in the tropical Pacific Ocean at periods of days to two months. This period band is of interest because the space-time scales of oceanic equatorial waves at these frequencies have historically made adequate observation of the variability difficult. These waves have zonal scales that are very large (exceeding 3000 km) and meridional scales that are relatively short (~100 km), making in situ measurements difficult, and the short temporal scales pose challenges for observation with satellite altimeters because the wave periods are short compared to orbit repeat periods. As a result, there has been relatively little progress since the early 1980s in characterizing and understanding these equatorial inertia-gravity and mixed Rossby-gravity waves. In this analysis, we seek to exploit the long zonal length scales of these high-frequency equatorial waves in an analysis of satellite scatterometer and altimeter data to shed new light on the properties and dynamics of these waves. At periods of 2-14 days, there is clear evidence for the presence of several basin-scale equatorial wave modes, including mixed Rossby-gravity waves and inertia-gravity waves associated with baroclinic modes one and two. Here, we focus on equatorial Kelvin waves and mixed Rossby-gravity waves forced in the western Pacific, and examine their variability in time and space and their relation to wind.

  11. Recurrence times and periodicities in 4U 1608-52 as observed by Vela 5B

    NASA Technical Reports Server (NTRS)

    Lochner, James C.; Roussel-Dupre, Diane

    1994-01-01

    We report on the Vela 5B 10 year history of the soft X-ray transient 4U 1608-52, and on the characteristics of its soft X-ray outbursts. The Vela 5B satellite observed the four known outbursts in 1975, 1977, and 1979, and four new outbursts in 1970 and 1971, altering the recurrence pattern of outbursts from this source. One of the 1970 outbursts is symmetric in its intensity profile, while the two outbursts in 1971 have short exponential profiles separated by 80 days. Despite suggestive recurrence periods of approximately 85 and approximately 150 days evident in the time intervals between the outbursts, there is no single statistically significant recurrence time on which the outbursts recur consistently. In the 1970 symmetric event, there is evidence for a period of either 4.10 or 5.19 days. Drawing upon the analogy with SU Ursa Majoris dwarf novae, we suggest that the short period is orbital and any longer period would be associated with a precession period of the accretion disk.

  12. Overview of patient dosimetry in diagnostic radiology in the USA for the past 50 years

    SciTech Connect

    Huda, Walter; Nickoloff, Edward L.; Boone, John M.

    2008-12-15

    This review covers the role of medical physics in addressing issues directly related to patient dosimetry in radiography, fluoroscopy, mammography, and CT. The sections on radiography and fluoroscopy radiation doses review the changes that have occurred during the last 50 to 60 years. A number of technological improvements have contributed to both a significant reduction in patient and staff radiation doses and improvements to the image quality during this period of time. There has been a transition from film-screen radiography with hand dip film processing to electronic digital imaging utilizing CR and DR. Similarly, fluoroscopy has progressed by directly viewing image intensifiers in darkened rooms to modern flat panel image receptor systems utilizing pulsed radiation, automated variable filtration, and digitally processed images. Mammography is one of the most highly optimized imaging procedures performed, because it is a repetitive screening procedure that results in annual radiation exposure. Mammography is also the only imaging procedure in the United States in which the radiation dose is regulated by the federal government. Consequently, many medical physicists have studied the dosimetry associated with screen-film and digital mammography. In this review, a brief history of mammography dose assessment by medical physicists is discussed. CT was introduced into clinical practice in the early 1970s, and has grown into one of the most important modalities available for diagnostic imaging. CT dose quantities and measurement techniques are described, and values of radiation dose for different types of scanner are presented. Organ and effective doses to adult patients are surveyed from the earliest single slice scanners, to the latest versions that include up to two x-ray tubes and can incorporate as many as 256 detector channels. An overview is provided of doses received by pediatric patients undergoing CT examinations, as well as methods, and results, of studies

  13. The Varying Light Curve and Timings of the Ultrashort-period Contact Binary KIC 9532219

    NASA Astrophysics Data System (ADS)

    Lee, Jae Woo; Hong, Kyeongsoo; Koo, Jae-Rim; Park, Jang-Ho

    2016-03-01

    KIC 9532219 is a W UMa-type eclipsing binary with an orbital period of 0.1981549 days that is below the short-period limit (˜0.22 days) of the period distribution for contact binaries. The Kepler light curve of the system exhibits striking changes in both eclipse depths and light maxima. Applying third-body and spot effects, the light-curve synthesis indicates that the eclipsing pair is currently in a marginal contact stage with a mass ratio of q = 1.20, an orbital inclination of i = 66.°0, a temperature difference of T1-T2 = 172 K, and a third light of l3 = 75.9%. To understand the light variations with time, we divided up the light curve into 312 segments and analyzed them separately. The results reveal that variation of eclipse depth is primarily caused by changing amounts of contamination due to the nearby star KIC 9532228 between the Kepler Quarters and that the variable O’Connell effect originates from the starspot activity on the less massive primary component. Based on our light-curve timings, a period study of KIC 9532219 indicates that the orbital period has varied as a combination of a downward parabola and a light-travel-time (LTT) effect due to a third body, which has a period of 1196 days and a minimum mass of 0.0892 M⊙ in an orbit of eccentricity 0.150. The parabolic variation could be a small part of a second LTT orbit due to a fourth component in a wider orbit, instead of either mass transfer or angular momentum loss.

  14. Building on 50 Years of Systems Engineering Experience for a New Era of Space Exploration

    NASA Technical Reports Server (NTRS)

    Dumbacher, Daniel L.; Lyles, Garry M.; McConnaughey, Paul K.

    2008-01-01

    Over the past 50 years, the National Aeronautics and Space Administration (NASA) has delivered space transportation solutions for America's complex missions, ranging from scientific payloads that expand knowledge, such as the Hubble Space Telescope, to astronauts and lunar rovers destined for voyages to the Moon. Currently, the venerable Space Shuttle, which has been in service since 1981, provides the United States (US) capability for both crew and heavy cargo to low-Earth orbit to construct the International Space Station, before the Shuttle is retired in 2010. In the next decade, NASA will replace this system with a duo of launch vehicles: the Ares I crew launch vehicle and the Ares V cargo launch vehicle. The goals for this new system include increased safety and reliability coupled with lower operations costs that promote sustainable space exploration for decades to come. The Ares I will loft the Orion crew exploration vehicle, while the heavy-lift Ares V will carry the Altair lunar lander, as well as the equipment and supplies needed to construct a lunar outpost for a new generation of human and robotic space pioneers. NASA's Marshall Space Flight Center manages the Shuttle's propulsion elements and is managing the design and development of the Ares rockets, along with a host of other engineering assignments in the field of scientific space exploration. Specifically, the Marshall Center's Engineering Directorate houses the skilled workforce and unique facilities needed to build capable systems upon the foundation laid by the Mercury, Gemini, Apollo, and Shuttle programs. This paper will provide details of the in-house systems engineering and vehicle integration work now being performed for the Ares I and planned for the Ares V. It will give an overview of the Ares I system-level testing activities, such as the ground vibration testing that will be conducted in the Marshall Center's Dynamic Test Stand to verify the integrated vehicle stack's structural

  15. Evidence for water cycle changes during past 50 years in Tibetan Plateau: Review and synthesis

    NASA Astrophysics Data System (ADS)

    Zhang, Y.

    2010-12-01

    The Tibetan Plateau, the largest geomorphologic unit on the Eurasian continent, and highest plateau in the world, exhibits “Asian water tower” A large amount of water is stored in the world’s highest and largest plateau, the Tibetan Plateau, in the forms of glaciers, snowpacks, lakes, and rivers. It is vital to understand whether the supply to these water resources has been experiencing any changes during recent global warming. Climate warming on the plateau in past decades has been suggested by meteorological observation and ice core records. The average annual and winter temperatures on the plateau rose about 0.16o and 0.32 o C per decade, respectively, from 1955 to 1996. The climatic warming trend seems more evident on the plateau than globally during the past 50 years. In response to the warming, one of the more important questions in hydrology is: if the climate warms in the future, will there be an intensification of the water cycle and, if so, what are evidence have been cached by current framework? There is considerable interest in this question because an intensification of the water cycle may lead to changes in water-resource availability, an increase in the frequency and intensity of droughts, and an amplification of warming through the water vapor feedback. Empirical evidence for ongoing intensification of the water cycle would provide additional support for the theoretical framework that links intensification with warming. There are 75 metrological observatories and 16 hydrological stations located on the Tibetan Plateau, comprising the Tibetan Autonomous Region, Qinghai Province, and parts of Sichuan and Gansu provinces, widely ranging from southern to northern part of the plateau. These data can be approximately regarded as natural flow data because the human water use is very small in quantity and can thus be ignored in these gauged catchments, These data were widely used in estimation of variation of runoff and evaporation. Various satellite

  16. Relationship between microbial diversity and chemical contamination along a 50-year-old sediment core

    NASA Astrophysics Data System (ADS)

    Berthe, T.; Petit, F.; Boust, D.; Lesueur, P.; Roose-Amsaleg, C.; Cécillon, S.; Kaci-Benaicha, A.

    2013-12-01

    The purpose of this study was to evaluate the potential use of sediment microbial diversity (community structure) as an indicator of the impact of anthropogenic activities within an estuarine ecosystem. The diversity of microbial communities was investigated along a 5-m-long sediment core collected in an anthropized European estuary (Seine, France), giving an evolution of trace metal, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) concentrations over the last 50 years. An increase of trace metal and PCB concentrations are observed with depth, with an enrichment of these contaminants in the 1970s. The concentration profiles of light, intermediate and heavy PAHs showed distinct peaks, but the highest total PAH concentration was also detected in the sediment from the 1970s. We first investigated the bacterial community resistant to cobalt, zinc and cadmium by analyzing the diversity of the czcA gene encoding an RND efflux pump (Heavy Metal Efflux-RND) in 5-year and 33-year-old sediment samples displaying contrasted concentrations in these trace metals. The diversity of the czcA gene was reduced in the 33-year-old and more contaminated sediments suggesting a selection of resistant bacterial species. A molecular fingerprinting method (DGGE) was used to study the evolution of total microbial (Bacteria and Archaea) community structures for samples selected along the sediment core. A correlation is observed between the bacterial community structures, the sediment age, the trace metal and PAH concentrations. The metabolically active and total microbial communities were further characterized by a microarray approach (Phylochips) in sediment samples selected according to the DGGE results. Bacterial diversity was found dominated by Proteobacteria, Actinobacteria, and Firmicutes in all analyzed samples. Diversity of phylotypes corresponds to changes in PAH and trace metal concentrations in sediment, suggesting that chemical contaminants have

  17. The Astrophysical r-Process 50 Years after B{sup 2}FH

    SciTech Connect

    Kratz, K.-L.; Pfeiffer, B.; Farouqi, K.; Mashonkina, L. I.

    2008-01-24

    Since the historical papers by Burbidge et al. and Cameron 50 years ago, it is generally accepted that half of the chemical elements above Fe are formed in explosive stellar scenarios by a rapid neutron-capture process (the classical ''r-process''). Already from their essential ideas, it became clear that a correct modelling of this nucleosynthesis process requires both, the knowledge of various nuclear properties very far from stability and a detailed description of the astrophysical environments. However, it took about three decades, until in 1986 the first experimental nuclear-physics data on the neutron-magic r-isotopes {sup 80}Zn and {sup 130}Cd could be obtained, which act as key ''waiting points'' in the respective A{approx_equal}80 and 130 peaks of the Solar-System (SS) r-abundances (N{sub r,{center_dot}}). Since then, using steadily improved nuclear data, we have optimized our r-process calculations to reproduce the present observables of the isotopic N{sub r,{center_dot}} ''residuals'', as well as the more recent elemental abundances in ultra-metal-poor, r-process-enriched halo stars. Concerning the latter observations, we support the basic idea about two different types of r-processes. Based on our many years' experience with the site-independent ''waiting-point approach'', we recently have extended our studies to fully dynamical network calculations for the most likely astrophysical r-process scenario, i.e. the high-entropy wind (HEW) of core-collapse type II supernovae (SN II). Again, an excellent reproduction of all observables for the ''main'' r-process has been achieved. However, a major difference is the nucleosynthesis origin of the lighter heavy elements in the 29{<=}Z{<=}45 mass region. Here, the HEW model predicts-instead of a ''weak'' neutron-capture r-process component-a primary rapid charged-particle process. This may explain the recent observations of a non-correlation of these elements with the heavier ''main'' r-process elements.

  18. EDITORIAL: International Conference on Finite Fermionic Systems: Nilsson Model 50 Years

    NASA Astrophysics Data System (ADS)

    2006-06-01

    In 1955 Sven Gösta Nilsson published the paper `Binding States of Individual Nucleons in Strongly Deformed Nuclei'. This eminent work has been crucial for the understanding of the structure of deformed atomic nuclei. Moreover, the so-called Nilsson model has been widely used for the description of other types of finite systems of fermions such as quantum dots and cold fermionic atoms. During one week in June 2005 we celebrated in Lund the 50th anniversary of the Nilsson model with the International Conference on Finite Fermionic Systems - Nilsson Model 50 Years. With the historical view in mind, the conference focused on present and future problems in nuclear structure physics as well as on the physics of other types of finite Fermi systems. As a background to the recent developments Nobel Laureate Ben Mottelson presented a recollection of early applications and achievements of the Nilsson model in the first talk of the conference, including a personal view of Sven Gösta Nilsson. We are particularly pleased that this contribution could be included in these proceedings. The scientific programme was structured according to the following subjects: Shell structure and deformations The heaviest elements and beyond Nuclei far from stability Pairing correlations Nuclear spectroscopy: large deformations Nuclear spectroscopy: rotational states Order and chaos Cold fermionic atoms Quantum dots Many new and interesting results were presented in the 15 invited talks, 30 oral contributions, and in the 33 papers of the poster sessions. The present volume of Physica Scripta contains most of the talks, as well as the short contributions of the posters. We thank the speakers and all participants who actively contributed to give this memorable conference a very high scientific level in the presented contributions, as well as in numerous discussions inside and outside the sessions. We also thank the international advisory committee for their invaluable work in helping us setting up

  19. Perceived weight discrimination in England: a population-based study of adults aged ⩾50 years

    PubMed Central

    Jackson, S E; Steptoe, A; Beeken, R J; Croker, H; Wardle, J

    2015-01-01

    Background: Despite a wealth of experimental studies on weight bias, little is known about weight discrimination at the population level. This study examined the prevalence and socio-demographic correlates of perceived weight discrimination in a large population-based sample of older adults. Methods: Data were from 5307 adults in the English Longitudinal Study of Ageing; a population-based cohort of men and women aged ⩾50 years. Weight discrimination was reported for five domains (less respect/courtesy; treated as less clever; poorer treatment in medical settings; poorer service in restaurants/stores; threatened/harassed) at wave 5 (2010–2011). Height and weight were measured at wave 4 (2008–2009). We used logistic regression to test the odds of weight discrimination in relation to weight status, age, sex, wealth, education and marital status. Results: Perceived weight discrimination in any domain was reported by 4.6% of participants, ranging from 0.8% in the normal-weight participants through 0.9, 6.7, 24.2 and 35.1% in individuals who were overweight or met criteria for class I, II and III obesity. Overall, and in each situation, odds of perceived weight discrimination were higher in younger and less wealthy individuals. There was no interaction between weight status and any socio-demographic variable. Relative to normal-weight participants, odds ratios for any perceived weight discrimination were 1.13 (95% confidence interval 0.53–2.40) in those who were overweight, 8.86 (4.65–16.88) in those with class I obesity, 35.06 (18.30–67.16) in class II obese and 56.43 (27.72–114.87) in class III obese. Conclusions: Our results indicate that rates of perceived weight discrimination are comparatively low in individuals who are overweight or have class I obesity, but for those with class II/III obesity, >10% had experienced discrimination in each domain, and >20% had been treated with less respect or courtesy. These findings have implications for public

  20. Effects of thinning intensities on transpiration and productivity of 50-year-old Pinus koraeinsis stands

    NASA Astrophysics Data System (ADS)

    Park, Juhan; Kim, Taekyu; Moon, Minkyu; Cho, Sungsik; Ryu, Daun; Kim, Hyun Seok

    2015-04-01

    This study investigated the effects of thinning intensities on stand transpiration and productivity of 50-year-old Korean pine forests for two years. Forest thinning, which removes some fraction of trees from stand, is widely conducted for reducing competition between remaining trees, improving tree productivity, reducing the risk of natural fire, and thus maintaining healthy forest. Forest thinning alters the microclimatic conditions such as radiation distribution within canopy, vapor pressure deficit, and amount of available soil water. These changes influence on the tree water use, and related productivity. Thinning was conducted on March, 2012 with two intensities (Control, Light-thinning (20%), and Heavy-thinning (40% of tree density)). Transpiration was estimated from sap flux density, which was measured with Granier-type thermal dissipation sensors. Tree diameter growth was measured with dendrometer, and converted to tree productivity using allometric equations developed specifically in our study sites. The climatic conditions showed little differences between two years. During the first growing season after thinning, stand transpiration was ca. 20% and 42% lower on light-thinning and heavy-thinning stand, respectively, even though sap flux density were higher in thinned stand. The difference in stand transpiration among treatments showed seasonal trends, so it was larger on summer when soil moisture was abundant due to monsoon, but was diminished on spring and autumn when soil moisture was limited. Tree-level productivity increased ca. 8% and 21% on light-thinning and heavy thinning stand, respectively. However, stand net primary production was ca. 20% lower on light-thinning stand, and ca. 31% on heavy-thinning stand. As a result, water use efficiency increased only in heavy-thinning stand. During the second growing season after thinning, stand transpiration was ca. 19% lower on light-thinning stand, and ca. 37% lower on heavy-thinning stand. The reduction

  1. Effects of thinning intensities on transpiration and productivity of 50-year-old Pinus koraeinsis stands

    NASA Astrophysics Data System (ADS)

    Park, J.; Kim, T.; Cho, S.; Ryu, D.; Moon, M.; Kim, H. S.

    2015-12-01

    This study investigated the effects of thinning intensities on stand transpiration and productivity of 50-year-old Korean pine forests for three years. Forest thinning, which remove some fraction of trees from stand, alters the microclimatic conditions such as radiation distribution within canopy, vapor pressure deficit, and amount of available soil water. These changes influence on the tree water use, and related tree growth. Thinning was conducted on March, 2012 with two intensities (Control, Light-thinning, and Heavy-thinning). Transpiration was estimated from sap flux density, which was measured with Granier-type thermal dissipation sensors. Tree diameter growth was measured with dendrometer, and converted to tree productivity using allometric equations developed specifically in our study sites.The climatic conditions showed remarkable differences among three years. In 2012, total precipitation was highest but spring was dry. 2013 was normal year with frequent rain events. In contrast, 2014 was hot and extremely dry. Stand transpiration was initially decreased ca. 20% and 42% on light-thinning and heavy-thinning stand, respectively. In second year, it gradually recovered in both thinning intensities, and was 19% and 37% lower on light-thinning and heavy-thinning stand, respectively. However, the recovery trends were different between two thinning intensities. Transpiration of heavy-thinning stand was recovered slowly than that of light thinning stand. In 2014, heavy-thinning stand transpired ca. 5% more than control plot in early growing season, but severe drought had negative effects that caused reduction of stand transpiration in thinned stand on late growing season. The tree-level productivity was increased initially ca. 24% and 28% on light-thinning and heavy-thinning stand, respectively. During the following growing seasons, this thinning-induced enhancement of productivity was diminished in light-thinning stand (21% in 2013 and 20% in 2014), but was

  2. Long Distance Bicycle Riding Causes Prostate-Specific Antigen to Increase in Men Aged 50 Years and Over

    PubMed Central

    Mejak, Sandra L.; Bayliss, Julianne; Hanks, Shayne D.

    2013-01-01

    Objectives To investigate whether bicycle riding alters total prostate-specific antigen (tPSA) serum concentrations in healthy older men. Methods 129 male participants, ranging in age from 50 to 71 years (mean 55 years), rode in a recreational group bicycle ride of between 55 and 160 kilometers. Blood samples for tPSA analysis were drawn within 60 minutes before starting, and within 5 minutes after completing the ride. The pre-cycling and post-cycling tPSA values were log transformed for normality and compared using paired t-tests. Linear regression was used to assess the relationship between changes in tPSA with age and distance cycled. Results Bicycle riding caused tPSA to increase by an average of 9.5% (95% CI = 6.1–12.9; p<0.001) or 0.23 ng/ml. The number of participants with an elevated tPSA (using the standard PSA normal range cut-off of 4.0 ng/ml) increased from two pre-cycle to six post-cycle (or from five to eight when using age-based normal ranges). Univariate linear regression analysis revealed that the change in tPSA was positively correlated with age and the distance cycled. Conclusions Cycling causes an average 9.5% increase in tPSA, in healthy male cyclists ≥50 years old, when measured within 5 minutes post cycling. We considered the increase clinically significant as the number of participants with an elevated PSA, according to established cut-offs, increased post-ride. Based on the research published to date, the authors suggest a 24–48 hour period of abstinence from cycling and ejaculation before a PSA test, to avoid spurious results. PMID:23418500

  3. Estimating the incubation period of raccoon rabies: a time-space clustering approach.

    PubMed

    Tinline, Rowland; Rosatte, Rick; MacInnes, Charles

    2002-11-29

    We used a time-space clustering approach to estimate the incubation period of raccoon rabies in the wild using data from the 1999-2001 invasion of raccoon rabies into eastern Ontario from northern New York State. The time differences and geographical distances between all possible pairs of rabies cases were computed, classified and assembled into a time-space matrix. The rows of that matrix represented differences in cases in weeks and the columns represent distances between cases in kilometers and the values in the cells of the matrix represent the counts of cases at specific time and distance intervals. There was a significant cluster of pairs 5 weeks apart with apparent harmonics at additional 5-week intervals. These results are explained by assuming the incubation period of raccoon rabies had a mode of 5 weeks. The time clusters appeared consistently at distance intervals of 5 km. We discuss the possibility that the spatial intervals were influenced by the 5 km radius of the point infection control depopulation process used in 1999 and the 10-15 km radial areas used in 2000. With the practical limits of those radii, there was an intensive effort to eliminate raccoons. Our procedure is easy to implement and provides an estimate of the shape of the distribution of incubation periods for raccoon rabies. PMID:12419602

  4. Periodic modulation in pulse arrival times from young pulsars: a renewed case for neutron star precession

    NASA Astrophysics Data System (ADS)

    Kerr, M.; Hobbs, G.; Johnston, S.; Shannon, R. M.

    2016-01-01

    In a search for periodic variation in the arrival times of pulses from 151 young, energetic pulsars, we have identified seven cases of modulation consistent with one or two harmonics of a single fundamental with time-scale 0.5-1.5 yr. We use simulations to show that these modulations are statistically significant and of high quality (sinusoidal) even when contaminated by the strong stochastic timing noise common to young pulsars. Although planetary companions could induce such modulation, the large implied masses and 2:1 mean motion resonances challenge such an explanation. Instead, the modulation is likely to be intrinsic to the pulsar, arising from quasi-periodic switching between stable magnetospheric states, and we propose that precession of the neutron star may regulate this switching.

  5. Periodic trim solutions with HP-version finite elements in time

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Finite Element in Time has been proven to be a powerful alternative solving strategy for the rotor craft trim problem. Additionally, Finite Element Method in Time has been developed in various versions like time-marching framework, Galerkin framework, Rayleigh-Ritz framework, and mixed formulation. Recently, this method was applied to the rotorcraft trim problem to obtain linearized solutions. The rotorcraft trim problem consists of trying to find a period solution for period-coefficient, differential equations subject to side constraints where certain force and momentum balance equations are forced to be equal to zero. There are free (or trim) parameters that are chosen to meet these side constraints. This project aims at expanding the application, in terms of the rotorcraft trim problem, from a linearized solution to nonlinear solution.

  6. Association of intrinsic circadian period with morningness-eveningness, usual wake time, and circadian phase

    NASA Technical Reports Server (NTRS)

    Duffy, J. F.; Rimmer, D. W.; Czeisler, C. A.

    2001-01-01

    The biological basis of preferences for morning or evening activity patterns ("early birds" and "night owls") has been hypothesized but has remained elusive. The authors reported that, compared with evening types, the circadian pacemaker of morning types was entrained to an earlier hour with respect to both clock time and wake time. The present study explores a chronobiological mechanism by which the biological clock of morning types may be set to an earlier hour. Intrinsic period, a fundamental property of the circadian system, was measured in a month-long inpatient study. A subset of participants also had their circadian phase assessed. Participants completed a morningness-eveningness questionnaire before study. Circadian period was correlated with morningness-eveningness, circadian phase, and wake time, demonstrating that a fundamental property of the circadian pacemaker is correlated with the behavioral trait of morningness-eveningness.

  7. Sex difference in the near-24-hour intrinsic period of the human circadian timing system

    PubMed Central

    Duffy, Jeanne F.; Cain, Sean W.; Chang, Anne-Marie; Phillips, Andrew J. K.; Münch, Mirjam Y.; Gronfier, Claude; Wyatt, James K.; Dijk, Derk-Jan; Czeisler, Charles A.

    2011-01-01

    The circadian rhythms of melatonin and body temperature are set to an earlier hour in women than in men, even when the women and men maintain nearly identical and consistent bedtimes and wake times. Moreover, women tend to wake up earlier than men and exhibit a greater preference for morning activities than men. Although the neurobiological mechanism underlying this sex difference in circadian alignment is unknown, multiple studies in nonhuman animals have demonstrated a sex difference in circadian period that could account for such a difference in circadian alignment between women and men. Whether a sex difference in intrinsic circadian period in humans underlies the difference in circadian alignment between men and women is unknown. We analyzed precise estimates of intrinsic circadian period collected from 157 individuals (52 women, 105 men; aged 18–74 y) studied in a month-long inpatient protocol designed to minimize confounding influences on circadian period estimation. Overall, the average intrinsic period of the melatonin and temperature rhythms in this population was very close to 24 h [24.15 ± 0.2 h (24 h 9 min ± 12 min)]. We further found that the intrinsic circadian period was significantly shorter in women [24.09 ± 0.2 h (24 h 5 min ± 12 min)] than in men [24.19 ± 0.2 h (24 h 11 min ± 12 min); P < 0.01] and that a significantly greater proportion of women have intrinsic circadian periods shorter than 24.0 h (35% vs. 14%; P < 0.01). The shorter average intrinsic circadian period observed in women may have implications for understanding sex differences in habitual sleep duration and insomnia prevalence. PMID:21536890

  8. A General Approach to Time Periodic Incompressible Viscous Fluid Flow Problems

    NASA Astrophysics Data System (ADS)

    Geissert, Matthias; Hieber, Matthias; Nguyen, Thieu Huy

    2016-06-01

    This article develops a general approach to time periodic incompressible fluid flow problems and semilinear evolution equations. It yields, on the one hand, a unified approach to various classical problems in incompressible fluid flow and, on the other hand, gives new results for periodic solutions to the Navier-Stokes-Oseen flow, the Navier-Stokes flow past rotating obstacles, and, in the geophysical setting, for Ornstein-Uhlenbeck and various diffusion equations with rough coefficients. The method is based on a combination of interpolation and topological arguments, as well as on the smoothing properties of the linearized equation.

  9. Time Periodic Solutions to the One-Dimensional Nonlinear Wave Equation

    NASA Astrophysics Data System (ADS)

    Ji, Shuguan; Li, Yong

    2011-02-01

    This paper is concerned with the time periodic solutions to the one-dimensional nonlinear wave equation with either variable or constant coefficients. By adjusting the basis of L 2 function space, we can circumvent the difficulties caused by η u = 0 and obtain the existence of a weak periodic solution, which was posed as an open problem by Baubu and Pavel in (Trans Am Math Soc 349:2035-2048, 1997). Finally, an application to the forced Sine-Gordon equation is presented to illustrate the utility of this technique.

  10. Plasticity of the Intrinsic Period of the Human Circadian Timing System

    PubMed Central

    Scheer, Frank A.J.L.; Wright, Kenneth P.; Kronauer, Richard E.; Czeisler, Charles A.

    2007-01-01

    Human expeditions to Mars will require adaptation to the 24.65-h Martian solar day-night cycle (sol), which is outside the range of entrainment of the human circadian pacemaker under lighting intensities to which astronauts are typically exposed. Failure to entrain the circadian time-keeping system to the desired rest-activity cycle disturbs sleep and impairs cognitive function. Furthermore, differences between the intrinsic circadian period and Earth's 24-h light-dark cycle underlie human circadian rhythm sleep disorders, such as advanced sleep phase disorder and non-24-hour sleep-wake disorders. Therefore, first, we tested whether exposure to a model-based lighting regimen would entrain the human circadian pacemaker at a normal phase angle to the 24.65-h Martian sol and to the 23.5-h day length often required of astronauts during short duration space exploration. Second, we tested here whether such prior entrainment to non-24-h light-dark cycles would lead to subsequent modification of the intrinsic period of the human circadian timing system. Here we show that exposure to moderately bright light (∼450 lux; ∼1.2 W/m2) for the second or first half of the scheduled wake episode is effective for entraining individuals to the 24.65-h Martian sol and a 23.5-h day length, respectively. Estimations of the circadian periods of plasma melatonin, plasma cortisol, and core body temperature rhythms collected under forced desynchrony protocols revealed that the intrinsic circadian period of the human circadian pacemaker was significantly longer following entrainment to the Martian sol as compared to following entrainment to the 23.5-h day. The latter finding of after-effects of entrainment reveals for the first time plasticity of the period of the human circadian timing system. Both findings have important implications for the treatment of circadian rhythm sleep disorders and human space exploration. PMID:17684566

  11. Geologic Exploration of the Planets: A Personal Retrospective of the First 50 years

    NASA Astrophysics Data System (ADS)

    Carr, M. H.

    2013-12-01

    The modern era of exploration of planets and satellites beyond the Earth-Moon system began on 14 December 1962 when the Mariner 2 spacecraft flew by Venus. Since that time roughly 80 spacecraft have successfully visited other planets and their satellites. In 1962 we knew nothing of the geology of the non-terrestrial planets and satellites; they were just variously shaded discs and dots. Most of us entering the new field of planetary geology at the time did so in anticipation of the Apollo lunar landings. I was hired by Gene Shoemaker to work on lunar issues and to participate in the lunar geologic mapping program that he had initiated at the USGS. Lunar studies led naturally to planetary studies but none of us could have anticipated the geologic variety that exists within the Solar System as exemplified by the coronae of Venus, the canyons of Mars, the volcanoes of Io, the ice tectonics of Europa and Ganymede, the geysers of Enceladus and the methane-carved valleys of Titan. Although Mars appeared lunar-like in the first close-up images from the Mariner 4 (1965) and Mariners 6 and 7 (1969) fly-bys, the Mariner 9 (1971) orbiter soon revealed Mars' geologic variety. Planning imaging for Mariner 9 was challenging; aids were primitive and we essentially had a blank sheet to fill. By 1971, the Viking Project with its main objective to land on Mars and search for signs of life was well underway. In 1969 I was appointed leader of the Viking Orbiter imaging team. The main function of the cameras was to ensure that the landing sites were safe before landing. In 1976 when we acquired the first close-up images of the pre-chosen landing sites they were greeted with elation and horror, elation because of their quality, horror because of the roughness of the terrain that had seemed so smooth in the Mariner 9 images. There followed an intense period of searching for safer sites and ultimately the two landers did land safely. The search for life then followed with hopes soaring as

  12. Medium Resolution Global Earth Observations with Landsat: Looking 35 Years Back and 50 Years Forward

    NASA Astrophysics Data System (ADS)

    Williams, D. L.; Irons, J. R.; Goward, S. N.

    2007-12-01

    The modern era of global medium resolution satellite remote sensing was inaugurated 35 years ago, in July 1972, with the launch of the first Landsat satellite carrying the Multispectral Scanner (MSS) sensor. Ten years after that first launch, Landsat 4 carried a much-improved sensor aloft, the Thematic Mapper. The TM provided better spatial resolution (30 m versus 79 m) than the MSS, as well as additional spectral bands in the mid- infrared (IR) and thermal IR regions. Roughly another decade later, in April 1999, the Enhanced Thematic Mapper Plus (ETM+) instrument was placed in orbit on Landsat 7. The ETM+ provided a new 15 m panchromatic band and a much-improved thermal band resolution (60 m versus 120 m). Through a combination of planning and good luck, the various Landsat missions have delivered a continuous set of calibrated, multispectral images of the Earth's surface spanning this entire 35-year time period. This imagery database has been used in agricultural evaluations, forest management inventories, geological surveys, water resource estimates, coastal zone appraisals, and a host of other applications to meet the needs of a very broad user community, including business, government, science, education, national security, and now -- even the casual observer -- as Landsat imagery provides the skeletal backbone of Google Earth. Landsat established the U.S. as the world leader in terrestrial remote sensing, contributed significantly to the understanding of the Earth's environment, spawned revolutionary uses of space-based data by the commercial value-added industry, and encouraged a new generation of commercial satellites that provide regional, high-resolution spatial images. In spite of the overall success of the Landsat series of satellites, the first 35 years of the Landsat legacy have been extremely challenging as the push to embrace new technologies was often questioned by those who simply wanted to maintain whatever the current capability was at that

  13. Dealing with periodical loads and harmonics in operational modal analysis using time-varying transmissibility functions

    NASA Astrophysics Data System (ADS)

    Weijtjens, Wout; Lataire, John; Devriendt, Christof; Guillaume, Patrick

    2014-12-01

    Periodical loads, such as waves and rotating machinery, form a problem for operational modal analysis (OMA). In OMA only the vibrations of a structure of interest are measured and little to nothing is known about the loads causing these vibrations. Therefore, it is often assumed that all dynamics in the measured data are linked to the system of interest. Periodical loads defy this assumption as their periodical behavior is often visible within the measured vibrations. As a consequence most OMA techniques falsely associate the dynamics of the periodical load with the system of interest. Without additional information about the load, one is not able to correctly differentiate between structural dynamics and the dynamics of the load. In several applications, e.g. turbines and helicopters, it was observed that because of periodical loads one was unable to correctly identify one or multiple modes. Transmissibility based OMA (TOMA) is a completely different approach to OMA. By using transmissibility functions to estimate the structural dynamics of the system of interest, all influence of the load-spectrum can be eliminated. TOMA therefore allows to identify the modal parameters without being influenced by the presence of periodical loads, such as harmonics. One of the difficulties of TOMA is that the analyst is required to find two independent datasets, each associated with a different loading condition of the system of interest. This poses a dilemma for TOMA; how can an analyst identify two different loading conditions when little is known about the loads on the system? This paper tackles that problem by assuming that the loading conditions vary continuously over time, e.g. the changing wind directions. From this assumption TOMA is developed into a time-varying framework. This development allows TOMA to not only cope with the continuously changing loading conditions. The time-varying framework also enables the identification of the modal parameters from a single dataset

  14. Stability and attractivity of periodic solutions of parabolic systems with time delays

    NASA Astrophysics Data System (ADS)

    Pao, C. V.

    2005-04-01

    This paper is concerned with the existence, stability, and global attractivity of time-periodic solutions for a class of coupled parabolic equations in a bounded domain. The problem under consideration includes coupled system of parabolic and ordinary differential equations, and time delays may appear in the nonlinear reaction functions. Our approach to the problem is by the method of upper and lower solutions and its associated monotone iterations. The existence of time-periodic solutions is for a class of locally Lipschitz continuous reaction functions without any quasimonotone requirement using Schauder fixed point theorem, while the stability and attractivity analysis is for quasimonotone nondecreasing and mixed quasimonotone reaction functions using the monotone iterative scheme. The results for the general system are applied to the standard parabolic equations without time delay and to the corresponding ordinary differential system. Applications are also given to three Lotka-Volterra reaction diffusion model problems, and in each problem a sufficient condition on the reaction rates is obtained to ensure the stability and global attractivity of positive periodic solutions.

  15. Primate enamel evinces long period biological timing and regulation of life history.

    PubMed

    Bromage, Timothy G; Hogg, Russell T; Lacruz, Rodrigo S; Hou, Chen

    2012-07-21

    The factor(s) regulating the combination of traits that define the overall life history matrix of mammalian species, comprising attributes such as brain and body weight, age at sexual maturity, lifespan and others, remains a complete mystery. The principal objectives of the present research are (1) to provide evidence for a key variable effecting life history integration and (2) to provide a model for how one would go about investigating the metabolic mechanisms responsible for this rhythm. We suggest here that a biological rhythm with a period greater than the circadian rhythm is responsible for observed variation in primate life history. Evidence for this rhythm derives from studies of tooth enamel formation. Enamel contains an enigmatic periodicity in its microstructure called the striae of Retzius, which develops at species specific intervals in units of whole days. We refer to this enamel rhythm as the repeat interval (RI). For primates, we identify statistically significant relationships between RI and all common life history traits. Importantly, RI also correlates with basal and specific metabolic rates. With the exception of estrous cyclicity, all relationships share a dependence upon body mass. This dependence on body mass informs us that some aspect of metabolism is responsible for periodic energy allocations at RI timescales, regulating cell proliferation rates and growth, thus controlling the pace, patterning, and co-variation of life history traits. Estrous cyclicity relates to the long period rhythm in a body mass-independent manner. The mass-dependency and -independency of life history relationships with RI periodicity align with hypothalamic-mediated neurosecretory anterior and posterior pituitary outputs. We term this period the Havers-Halberg Oscillation (HHO), in reference to Clopton Havers, a 17th Century hard tissue anatomist, and Franz Halberg, a long-time explorer of long-period rhythms. We propose a mathematical model that may help elucidate

  16. Time domain spectral method and its application on antenna array and PCB trace with periodic roughness

    NASA Astrophysics Data System (ADS)

    Wang, Minshen

    The primary interest of the electromagnetic behavior of a periodic structure is in its near field and far field. However, it is still numerically difficult to analyze either one in the time domain. The primary goal of this dissertation is to develop corresponding time domain technique to analyze two topics. The first one is to evaluate the far field of a realistic, large antenna array using an efficient method. The second one is to evaluate the propagation characteristic of a commercially available printed circuit board (PCB) with intentional roughness. Both of which are hot topics in the antenna and signal integrity (SI) society respectively; however, none of them have ever been solved in the time domain. To efficiently evaluate the far field pattern of a realistically large antenna array, the spectral domain method and the reciprocity theorem are implemented in the finite difference time domain (FDTD) technique to avoid the simulation of the near field. By taking advantage of the periodic boundary condition (PBC), the proposed method demonstrates its capability to speed up far field evaluation from hours to minutes. Good agreement of the results is provided for various cases: circular antenna array, arbitrary feeding array, and highly directional leaky wave antenna, etc. Periodic structure modeling with finite sized feedings is developed by the array scanning method (ASM) implemented in the FDTD technique. The minimally coupled electric and magnetic co-mingled antenna array is evaluated by the method. Moreover, a commercially available PCB with very small roughness is modeled by the ASM-FDTD and the propagation characteristic is evaluated. Both are evaluated by time domain method for the first time. Efficiency in terms of memory and computing time is shown for this method and parallelization in the future is proposed.

  17. Spin-dependent tunneling time in periodic diluted-magnetic-semiconductor/nonmagnetic-barrier superlattices

    NASA Astrophysics Data System (ADS)

    Yang, Ping-Fan; Guo, Yong

    2016-02-01

    We investigate the tunneling time (dwell time) in periodic diluted-magnetic-semiconductor/nonmagnetic-barrier (DMS/NB) superlattices subjected to an external magnetic field. It is found that spin-dependent resonant bands form in the spectra of dwell time, which can be effectively manipulated by not only the external magnetic field but also the geometric parameters of the system. Moreover, an intuitive semiclassical delay is defined to illustrate the behavior of the dwell time, and the former one is shown to be the result of "smoothing out" the latter one. We also find that the dwell time in diluted-magnetic-semiconductor/semiconductor superlattices behaves surprisingly different from the DMS/NB case, especially for spin-down electrons.

  18. Computation of symmetric, time-periodic solutions of the vortex sheet with surface tension

    PubMed Central

    Ambrose, David M.; Wilkening, Jon

    2010-01-01

    A numerical method is introduced for the computation of time-periodic vortex sheets with surface tension separating two immiscible, irrotational, two-dimensional ideal fluids of equal density. The approach is based on minimizing a nonlinear functional of the initial conditions and supposed period that is positive unless the solution is periodic, in which case it is zero. An adjoint-based optimal control technique is used to efficiently compute the gradient of this functional. Special care is required to handle singular integrals in the adjoint formulation. Starting with a solution of the linearized problem about the flat rest state, a family of smooth, symmetric breathers is found that, at quarter-period time intervals, alternately pass through a flat state of maximal kinetic energy, and a rest state in which all the energy is stored as potential energy in the interface. In some cases, the interface overturns before returning to the initial, flat configuration. It is found that the bifurcation diagram describing these solutions contains several disjoint curves separated by near-bifurcation events. PMID:20133691

  19. First-Passage and Residence Times in a Periodically Driven Integrate-and-Fire Model

    NASA Astrophysics Data System (ADS)

    Talkner, Peter; Schindler, Michael; Hänggi, Peter

    2004-03-01

    The stochastic integrate-and-fire model presents a simple description of the spiking behavior of neurons.In this model a neuron ``fires'' if an Ornstein-Uhlenbeck process crosses a prescribed threshold. After the firing the process is assumed to be in a refractory state, and from there it is put back into its initial, active state.This process can be characterized by the distribution of the first passage times of the threshold and by the residence times in the active states.We determined the distributions of these times for the integrate-and-fire model for short refractory times in the presence of a periodic signal.This is done by numerical solutions both of the respective Langevin equation and the equivalent Fokker-Planck equation. The results are compared with an approximate analytic theory. If the period of the signal is large compared to the relaxation time of the Ornstein-Uhlenbeck process and if the threshold is higher than a few times the noise strength we find theory and numerics to be in excellent agreement.

  20. Tracing temperature in a nanometer size region in a picosecond time period.

    PubMed

    Nakajima, Kaoru; Kitayama, Takumi; Hayashi, Hiroaki; Matsuda, Makoto; Sataka, Masao; Tsujimoto, Masahiko; Toulemonde, Marcel; Bouffard, Serge; Kimura, Kenji

    2015-01-01

    Irradiation of materials with either swift heavy ions or slow highly charged ions leads to ultrafast heating on a timescale of several picosecond in a region of several nanometer. This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies. These nanostructures are believed to be formed when the local temperature rises beyond the melting or boiling point of the material. Conventional techniques, however, are not applicable to measure temperature in such a localized region in a short time period. Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position. The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model. PMID:26293488

  1. Is the use of underwater polarized light by fish restricted to crepuscular time periods?

    PubMed

    Novales Flamarique, I; Hawryshyn, C W

    1997-04-01

    We measured the spectral distributions of the underwater total and polarized light fields in the upper photic zone of meso-eutrophic waters (i.e., blue-green waters containing medium to high chlorophyll a concentrations). Per cent polarization levels during the day were always lower than 40%, but at crepuscular times these values could increase to 67%. A corresponding change occurred in the spectral distribution, with proportionately more shorter wavelength photons contributing to the total spectrum during crepuscular periods. Electrophysiological recordings from the optic nerve of rainbow trout subjected to light stimuli of varying polarization percentages show that the animal's threshold for detecting polarized light is between 63 and 72%. These physiological findings suggest that the use of water-induced polarized light cues by rainbow trout and similar percomorph fish should be restricted to crepuscular time periods. PMID:9196717

  2. Tracing temperature in a nanometer size region in a picosecond time period

    NASA Astrophysics Data System (ADS)

    Nakajima, Kaoru; Kitayama, Takumi; Hayashi, Hiroaki; Matsuda, Makoto; Sataka, Masao; Tsujimoto, Masahiko; Toulemonde, Marcel; Bouffard, Serge; Kimura, Kenji

    2015-08-01

    Irradiation of materials with either swift heavy ions or slow highly charged ions leads to ultrafast heating on a timescale of several picosecond in a region of several nanometer. This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies. These nanostructures are believed to be formed when the local temperature rises beyond the melting or boiling point of the material. Conventional techniques, however, are not applicable to measure temperature in such a localized region in a short time period. Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position. The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model.

  3. Tracing temperature in a nanometer size region in a picosecond time period

    PubMed Central

    Nakajima, Kaoru; Kitayama, Takumi; Hayashi, Hiroaki; Matsuda, Makoto; Sataka, Masao; Tsujimoto, Masahiko; Toulemonde, Marcel; Bouffard, Serge; Kimura, Kenji

    2015-01-01

    Irradiation of materials with either swift heavy ions or slow highly charged ions leads to ultrafast heating on a timescale of several picosecond in a region of several nanometer. This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies. These nanostructures are believed to be formed when the local temperature rises beyond the melting or boiling point of the material. Conventional techniques, however, are not applicable to measure temperature in such a localized region in a short time period. Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position. The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model. PMID:26293488

  4. Periodic solutions of a nonautonomous predator-prey system with stage structure and time delays

    NASA Astrophysics Data System (ADS)

    Xu, Rui; Wang, Zhiqiang

    2006-11-01

    A nonautonomous Lotka-Volterra type predator-prey model with stage structure and time delays is investigated. It is assumed in the model that the individuals in each species may belong to one of two classes: the immatures and the matures, the age to maturity is presented by a time delay, and that the immature predators do not feed on prey and do not have the ability to reproduce. By some comparison arguments we first discuss the permanence of the model. By using the continuation theorem of coincidence degree theory, sufficient conditions are derived for the existence of positive periodic solutions to the model. By means of a suitable Lyapunov functional, sufficient conditions are obtained for the uniqueness and global stability of the positive periodic solutions to the model.

  5. Time functions of deep earthquakes from broadband and short-period stacks

    USGS Publications Warehouse

    Houston, H.; Benz, H.M.; Vidale, J.E.

    1998-01-01

    To constrain dynamic source properties of deep earthquakes, we have systematically constructed broadband time functions of deep earthquakes by stacking and scaling teleseismic P waves from U.S. National Seismic Network, TERRAscope, and Berkeley Digital Seismic Network broadband stations. We examined 42 earthquakes with depths from 100 to 660 km that occurred between July 1, 1992 and July 31, 1995. To directly compare time functions, or to group them by size, depth, or region, it is essential to scale them to remove the effect of moment, which varies by more than 3 orders of magnitude for these events. For each event we also computed short-period stacks of P waves recorded by west coast regional arrays. The comparison of broadband with short-period stacks yields a considerable advantage, enabling more reliable measurement of event duration. A more accurate estimate of the duration better constrains the scaling procedure to remove the effect of moment, producing scaled time functions with both correct timing and amplitude. We find only subtle differences in the broadband time-function shape with moment, indicating successful scaling and minimal effects of attenuation at the periods considered here. The average shape of the envelopes of the short-period stacks is very similar to the average broadband time function. The main variations seen with depth are (1) a mild decrease in duration with increasing depth, (2) greater asymmetry in the time functions of intermediate events compared to deep ones, and (3) unexpected complexity and late moment release for events between 350 and 550 km, with seven of the eight events in that depth interval displaying markedly more complicated time functions with more moment release late in the rupture than most events above or below. The first two results are broadly consistent with our previous studies, while the third is reported here for the first time. The greater complexity between 350 and 550 km suggests greater heterogeneity in

  6. Sobolev type equations of time-fractional order with periodical boundary conditions

    NASA Astrophysics Data System (ADS)

    Plekhanova, Marina

    2016-08-01

    The existence of a unique local solution for a class of time-fractional Sobolev type partial differential equations endowed by the Cauchy initial conditions and periodical with respect to every spatial variable boundary conditions on a parallelepiped is proved. General results are applied to study of the unique solvability for the initial boundary value problem to Benjamin-Bona-Mahony-Burgers and Allair partial differential equations.

  7. Conditions for Recurrence of a Flow of Physical Events with Unextendable Dead Time Period

    NASA Astrophysics Data System (ADS)

    Nezhel'skaya, L. A.

    2016-04-01

    A flow of physical events (photons, electrons, etc.) is studied. One of the mathematical models of such flows is the modulated MAP flow of events circulating under conditions of unextendable dead time period. The explicit form of the probability density of interarrival interval of the flow is presented together with the explicit form of the joint probability density of two adjacent intervals in the observed flow. The conditions for recurrence of the observable flow of events are presented.

  8. Thermal characteristics of time-periodic electroosmotic flow in a circular microchannel

    NASA Astrophysics Data System (ADS)

    Moghadam, Ali Jabari

    2015-10-01

    A theoretical analysis is performed to explore the thermal characteristics of electroosmotic flow in a circular microchannel under an alternating electric field. An analytical approach is presented to solve energy equation, and then, the exact solution of temperature profiles is obtained by using the Green's function method. This study reveals that the temperature field repeats itself for each half-period. Frequency has a strong influence on the thermal behavior of the flow field. For small values of the dimensionless frequency (small channel size, large kinematic viscosity, or small frequency), the advection mechanism is dominant in the whole domain and the resultant heating (Joule heating and wall heat flux) can be transferred by the complete flow field in the axial direction; while, the middle portion of the flow field at high dimensionless frequencies does not have sufficient time to transfer heat by advection, and the bulk fluid temperature, especially in heating, may consequently become greater than the wall temperature. In a particular instance of cooling mode, a constant surface temperature case is temporarily occurred in which the axial temperature gradient will be zero. For relatively high frequencies, the unsteady bulk fluid temperature in some radial positions at some moments may be equal to the wall temperature; hence instantaneous cylindrical surfaces with zero radial heat flux may occur over a period of time. Depending on the value and sign of the thermal scale ratio, the quasi-steady-state Nusselt number (time-averaged at one period) approaches a specific value as the electrokinetic radius becomes infinity.

  9. Enhancement in dentin collagen’s biological stability after proanthocyanidins treatment in clinically relevant time periods

    PubMed Central

    Liu, Yi; Chen, Mingsheng; Yao, Xiaomei; Xu, Changqi; Zhang, Ying; Wang, Yong

    2013-01-01

    Objective To investigate whether proanthocyanidins (PA) is capable of improving dentin collagen’s biological stability through cross-linking within time periods that are clinically relevant. Materials and methods Demineralized dentin collagen slabs were treated with 3.75 wt% PA solution for 10 s, 1 min, 30 min, 60 min, 120 min, 360 min, and 720 min, respectively. The resultant cross-linked collagen samples were subject to digestion with 0.1% collagenase at 37 °C for 2 h, 6 h, 12 h, 24 h, 36 h, and 48 h. The percentage of weight loss after digestion was calculated to evaluate PA-treated collagen’s resistance toward enzymatic degradation. Fourier-Transformed Infrared (FTIR) spectroscopy was used to probe evidences of PA-collagen interactions after various periods of PA treatment. Results The collagenase digestion assay suggests that PA treatment as short as 10 s can enhance collagen’s resistance toward enzymatic challenge. The FTIR spectroscopy further verifies that PA is indeed incorporated into collagen regardless of treatment time, possibly via a mechanism involving the chemical interactions between PA and collagen. Significance This study confirmed that PA can effectively cross-link collagen and improve its biological stability in time periods as short as 10 s. The use of PA as a priming agent is therefore clinically feasible and is a promising approach to improving the durability of current dentin bonding systems. PMID:23434233

  10. Time-frequency manifold correlation matching for periodic fault identification in rotating machines

    NASA Astrophysics Data System (ADS)

    He, Qingbo; Wang, Xiangxiang

    2013-05-01

    For rotating machines, the localized faults of key components generally represent as periodic transient impulses in vibration signals. The existence of background noise will corrupt transient impulses in practice, and will thus increase the difficulty to identify specific faults. This paper combines the concepts of time-frequency manifold (TFM) and image template matching, and proposes a novel TFM correlation matching method to enhance identification of the periodic faults. This method is to conduct correlation matching of a vibration signal in the time-frequency domain by using the TFM with a short duration as a template. By this method, the time-frequency distribution (TFD) of a vibration signal is firstly achieved by the Smoothed Pseudo-Wigner-Ville distribution (SPWVD) method. Then the TFM template is learned to do correlation matching with the TFD of the analyzed signal. Finally, the ridge is extracted from the correlation matching image and the ridge coefficients are analyzed for periodic fault identification. The proposed method takes advantages of the TFM in noise suppression and template matching in object enhancement, and can enhance the fault impulses of interest in a unified scale. The novel method is verified to be superior to traditional enveloping method with providing smoother and clearer fault impulse component via applications to gearbox fault detection and bearing defect identification.

  11. An approach to identify time consistent model parameters: sub-period calibration

    NASA Astrophysics Data System (ADS)

    Gharari, S.; Hrachowitz, M.; Fenicia, F.; Savenije, H. H. G.

    2013-01-01

    Conceptual hydrological models rely on calibration for the identification of their parameters. As these models are typically designed to reflect real catchment processes, a key objective of an appropriate calibration strategy is the determination of parameter sets that reflect a "realistic" model behavior. Previous studies have shown that parameter estimates for different calibration periods can be significantly different. This questions model transposability in time, which is one of the key conditions for the set-up of a "realistic" model. This paper presents a new approach that selects parameter sets that provide a consistent model performance in time. The approach consists of testing model performance in different periods, and selecting parameter sets that are as close as possible to the optimum of each individual sub-period. While aiding model calibration, the approach is also useful as a diagnostic tool, illustrating tradeoffs in the identification of time-consistent parameter sets. The approach is applied to a case study in Luxembourg using the HyMod hydrological model as an example.

  12. Periodic Time-Domain Nonlocal Nonreflecting Boundary Conditions for Duct Acoustics

    NASA Technical Reports Server (NTRS)

    Watson, Willie R.; Zorumski, William E.

    1996-01-01

    Periodic time-domain boundary conditions are formulated for direct numerical simulation of acoustic waves in ducts without flow. Well-developed frequency-domain boundary conditions are transformed into the time domain. The formulation is presented here in one space dimension and time; however, this formulation has an advantage in that its extension to variable-area, higher dimensional, and acoustically treated ducts is rigorous and straightforward. The boundary condition simulates a nonreflecting wave field in an infinite uniform duct and is implemented by impulse-response operators that are applied at the boundary of the computational domain. These operators are generated by convolution integrals of the corresponding frequency-domain operators. The acoustic solution is obtained by advancing the Euler equations to a periodic state with the MacCormack scheme. The MacCormack scheme utilizes the boundary condition to limit the computational space and preserve the radiation boundary condition. The success of the boundary condition is attributed to the fact that it is nonreflecting to periodic acoustic waves. In addition, transient waves can pass rapidly out of the solution domain. The boundary condition is tested for a pure tone and a multitone source in a linear setting. The effects of various initial conditions are assessed. Computational solutions with the boundary condition are consistent with the known solutions for nonreflecting wave fields in an infinite uniform duct.

  13. Time-varying singular value decomposition for periodic transient identification in bearing fault diagnosis

    NASA Astrophysics Data System (ADS)

    Zhang, Shangbin; Lu, Siliang; He, Qingbo; Kong, Fanrang

    2016-09-01

    For rotating machines, the defective faults of bearings generally are represented as periodic transient impulses in acquired signals. The extraction of transient features from signals has been a key issue for fault diagnosis. However, the background noise reduces identification performance of periodic faults in practice. This paper proposes a time-varying singular value decomposition (TSVD) method to enhance the identification of periodic faults. The proposed method is inspired by the sliding window method. By applying singular value decomposition (SVD) to the signal under a sliding window, we can obtain a time-varying singular value matrix (TSVM). Each column in the TSVM is occupied by the singular values of the corresponding sliding window, and each row represents the intrinsic structure of the raw signal, namely time-singular-value-sequence (TSVS). Theoretical and experimental analyses show that the frequency of TSVS is exactly twice that of the corresponding intrinsic structure. Moreover, the signal-to-noise ratio (SNR) of TSVS is improved significantly in comparison with the raw signal. The proposed method takes advantages of the TSVS in noise suppression and feature extraction to enhance fault frequency for diagnosis. The effectiveness of the TSVD is verified by means of simulation studies and applications to diagnosis of bearing faults. Results indicate that the proposed method is superior to traditional methods for bearing fault diagnosis.

  14. 50 years of monitoring of the ozone layer in the Czech Republic - results and challenges

    NASA Astrophysics Data System (ADS)

    Vanicek, Karel; Skrivankova, Pavla; Metelka, Ladislav; Stanek, Martin

    2010-05-01

    Long-term observations of total ozone (TOZ) and vertical ozone profiles, the basic parameters of the ozone layer, have been performed at the Solar and Ozone Observatory (SOO) Hradec Kralove and at the Aerological Department (AD) Praha of the Czech Hydrometeorological Institute (CHMI) since 1961 and 1992 respectively. The Dobson and Brewer spectrophotometers regularly calibrated towards the international references and electro-chemical ECC ozone sondes are used for the measurements. The observations contribute to the global GAW and NDACC ozone monitoring systems. Up to now analyses of the data give the basic findings given bellow and documented in the presentation. Some of them have important implication to the international ozone monitoring infrastructure, as well. - The decrease of TOZ by about 5-7 % in the winter-spring months towards the pre ozone-hole period have occurred since the mid eighties. This is in good agreement by the magnitude and time with depletion of the ozone layer due to chemical destruction of ozone in the NH mid-latitudes. - Significant depletion 3-5 % of TOZ has been identified also in the summer season since the early nineties. As this can not be attributed to the man-made chemical processes a change in the UT/LS dynamics over Central Europe is the most probable reason. - Aerological measurements taken at AD show that the summer reduction of TOZ very well coincides with a change of UT/LS temperature that persists for about two decades over the Czech territory. Therefore it has a long-term character that can be regarded as a climate shift in UT/LS and need to be further investigated. - 15 years of unique simultaneous Dobson/Brewer observations of TOZ performed at SOO show systematic seasonal deviations between both data sets that exceed instrumental accuracy of measurements. The differences are mostly caused by different wavelengths and their ozone absorption coefficients used by both instruments. As the Brewer observations are being

  15. Variation of the Earth tide-seismicity compliance parameter the last 50 years for the seismic area of Evoikos, Greece

    NASA Astrophysics Data System (ADS)

    Contadakis, Michael E.; Arabelos, Demetrious N.; Vergos, George; Spatalas, Spyrous

    2015-04-01

    The results of the analysis of the last 50 years earthquakes series in seismic active areas of Greece, i.e. the areas (a) of the Mygdonian Basin(Contadakis et al. 2007), (b) of the Ionian Islands (Contadakis et al. 2012 ) and (c) of the Hellenic Arc (Vergos et al. 2012 ), indicate that the monthly variation of the frequencies of earthquake occurrence is in accordance with the period of the tidal lunar monthly and semi-monthly (Mm and Mf) variations. The same happens with the corresponding daily variations of the frequencies of earthquake occurrence with the diurnal luni-solar (K1, O1) and semidiurnal lunar (M2) and solar (S2) tidal variations. In addition the confidence level for the identification of such period accordance between earthquakes occurrence frequency and tidal periods varies with seismic activity, i.e. the higher confidence level corresponds to periods with stronger seismic activity. These results are in favor of a tidal triggering process on earthquakes when the stress in the focal area is near the critical level. Based on these results, we consider the confidence level of earthquake frequency of occurrence - tidal period accordance, p, as an index of tectonic stress criticality for earthquake occurrence. A test on posterior of this idea, (i.e. the value of the confidence level index, p, indicate the fault matureness) in the case of the recent seismic activity at Fthiotida, was positive (Contadakis et al 2014). In this paper we present the results of a second test by the occasion of the recent seismic activity of Central Evoikos. The results also are positive. We suggest that this compliance parameter may be used as an additional element for the seismic risk assessment. References Cadicheanu, N., van Ruymbeke, M and Zhu P.,2007:Tidal triggering evidence of intermediate depth earthquakes in Vrancea zone(Romania), NHESS 7,733-740. Contadakis, M. E., Arabelos, D. N., Spatalas, S., 2009, Evidence for tidal triggering on the shallow earthquakes of the

  16. Spacecraft stability and control using new techniques for periodic and time-delayed systems

    NASA Astrophysics Data System (ADS)

    NAzari, Morad

    This dissertation addresses various problems in spacecraft stability and control using specialized theoretical and numerical techniques for time-periodic and time-delayed systems. First, the effects of energy dissipation are considered in the dual-spin spacecraft, where the damper masses in the platform (?) and the rotor (?) cause energy loss in the system. Floquet theory is employed to obtain stability charts for different relative spin rates of the subsystem [special characters omitted] with respect to the subsystem [special characters omitted]. Further, the stability and bifurcation of delayed feedback spin stabilization of a rigid spacecraft is investigated. The spin is stabilized about the principal axis of the intermediate moment of inertia using a simple delayed feedback control law. In particular, linear stability is analyzed via the exponential-polynomial characteristic equations and then the method of multiple scales is used to obtain the normal form of the Hopf bifurcation. Next, the dynamics of a rigid spacecraft with nonlinear delayed multi-actuator feedback control are studied, where a nonlinear feedback controller using an inverse dynamics approach is sought for the controlled system to have the desired linear delayed closed-loop dynamics (CLD). Later, three linear state feedback control strategies based on Chebyshev spectral collocation and the Lyapunov Floquet transformation (LFT) are explored for regulation control of linear periodic time delayed systems. First , a delayed feedback control law with discrete delay is implemented and the stability of the closed-loop response is investigated in the parameter space of available control gains using infinite-dimensional Floquet theory. Second, the delay differential equation (DDE) is discretized into a large set of ordinary differential equations (ODEs) using the Chebyshev spectral continuous time approximation (CSCTA) and delayed feedback with distributed delay is applied. The third strategy involves

  17. Quasiequilibrium directed hopping in a time-dependent two-well periodic potential

    NASA Astrophysics Data System (ADS)

    Rozenbaum, V. M.; Shapochkina, I. V.

    2011-11-01

    We consider the directed motion of a Brownian particle in a two-well periodic potential with time-varying barriers and wells described by arbitrary periodic functions of time, v(t) and u(t), alternating with the period τ. In the framework of the low-temperature kinetic approach, we obtain explicit formulas for the probabilities of finding the particle in potential wells, average velocity of directed motion, input energy Pin and useful work Pout against additionally introduced stationary load force f. These formulas are considerably simplified by the assumption of the quasiequilibrium regime of motion corresponding to small values of u(t) and f. It is shown that depending on the same or opposite parity of the functions v(t) and u(t) with respect to time reversal, the motion direction of a Brownian particle is retained or reversed under the reversal of the direction of movement along the (v-u) loop in the phase space of the functions v(t) and u(t), and the nondiagonal kinetic coefficients are mutually symmetric or antisymmetric. In the adiabatic limit τ→∞, the average velocity is proportional to τ-1 in two cases: (i) the above loop has a nonzero area, (ii) the functions v(t) and u(t) are proportional to each other (zero loop area) and include intervals of fast changes with small durations τ0 on the period τ of their variations. In both of these cases, the efficiency of energy conversion, η=Pout/Pin, tends to unity at large variations of the barriers v(t). In the second case, the deviation of η from unity can be split into two contributions: The former decreases exponentially with increasing amplitude v0 of v(t), while the latter is a small nonadiabatic correction proportional to v0-3/2. It is the nonadiabatic correction that limits high efficiencies at large variations of barriers.

  18. Infrared Time Lags for the Periodic Quasar PG 1302-102

    NASA Astrophysics Data System (ADS)

    Jun, Hyunsung D.; Stern, Daniel; Graham, Matthew J.; Djorgovski, S. G.; Mainzer, Amy; Cutri, Roc M.; Drake, Andrew J.; Mahabal, Ashish A.

    2015-11-01

    The optical light curve of the quasar PG 1302-102 at z=0.278 shows a strong, smooth 5.2 year periodic signal, detectable over a period of ∼20 years. Although the interpretation of this phenomenon is still uncertain, the most plausible mechanisms involve a binary system of two supermassive black holes with a subparsec separation. At this close separation, the nuclear black holes in PG 1302-102 will likely merge within ∼ {10}5 years due to gravitational wave emission alone. Here, we report the rest-frame near-infrared time lags for PG 1302-102. Compiling data from WISE and Akari, we confirm that the periodic behavior reported in the optical light curve from Graham et al. is reproduced at infrared wavelengths, with best-fit observed-frame 3.4 and 4.6 μ {{m}} time lags of (2219 ± 153, 2408 ± 148) days for a near face-on orientation of the torus, or (4103 ± 153, 4292 ± 148) days for an inclined system with relativistic Doppler boosting in effect. The periodicity in the infrared light curves and the light-travel time of the accretion disk photons to reach the dust glowing regions support that a source within the accretion disk is responsible for the optical variability of PG 1302-102, echoed at the farther out dusty regions. The implied distance of this dusty, assumed toroidal region is ∼1.5 pc for a near face-on geometry or ∼1.1 pc for the relativistic Doppler-boosted case.

  19. Timing Studies of X Persei and the Discovery of Its Transient Quasi-periodic Oscillation Feature

    NASA Technical Reports Server (NTRS)

    Acuner, Z.; Inam,S. C.; Sahiner, S.; Serim, M. M.; Baykal, A.; Swank, J.

    2014-01-01

    We present a timing analysis of X Persei (X Per) using observations made between 1998 and 2010 with the Proportional Counter Array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE) and with the INTEGRAL Soft Gamma-Ray Imager (ISGRI). All pulse arrival times obtained from the RXTE-PCA observations are phase-connected and a timing solution is obtained using these arrival times. We update the long-term pulse frequency history of the source by measuring its pulse frequencies using RXTE-PCA and ISGRI data. From the RXTEPCA data, the relation between the frequency derivative and X-ray flux suggests accretion via the companion's stellar wind. However, the detection of a transient quasi-periodic oscillation feature, peaking at approximately 0.2 Hz, suggests the existence of an accretion disc. We find that doublebreak models fit the average power spectra well, which suggests that the source has at least two different accretion flow components dominating the overall flow. From the power spectrum of frequency derivatives, we measure a power-law index of approximately - 1, which implies that, on short time-scales, disc accretion dominates over noise, while on time-scales longer than the viscous time-scales, the noise dominates. From pulse profiles, we find a correlation between the pulse fraction and the count rate of the source.

  20. Escape rate for a quantum particle moving in a time-periodic rapidly oscillating potential: a time-independent approach.

    PubMed

    Shit, Anindita; Chattopadhyay, Sudip; Chaudhuri, Jyotipratim Ray

    2012-05-01

    We explore, in the quantum regime, the stochastic dynamics of a time-periodic, rapidly oscillating potential (having a characteristic frequency of ω) within the framework of a time-dependent system-reservoir Hamiltonian. We invoke the idea of a quantum gauge transformation in light of the standard Floquet theorem in an attempt to construct a Langevin equation (bearing a time-independent effective potential) by employing a systematic perturbative expansion in powers of ω^{-1} using the natural time-scale separation. The time-independent effective potential (corrected to ω^{-2} in leading order) that acts on the slow motion of the driven particle can be employed for trapping. We proceed further to evaluate the rate of escape of the driven particle from the metastable state in the high-temperature limit. We also envisage a resonance phenomena, a true hallmark of the system-reservoir quantization. This development would thus serve as a model template to investigate the trapping mechanism, as well as an appropriate analog to understand the dynamics of a fluctuation-induced escape process from the trap. PMID:23004698

  1. Transfer-matrix approach for finite-difference time-domain simulation of periodic structures.

    PubMed

    Deinega, Alexei; Belousov, Sergei; Valuev, Ilya

    2013-11-01

    Optical properties of periodic structures can be calculated using the transfer-matrix approach, which establishes a relation between amplitudes of the wave incident on a structure with transmitted or reflected waves. The transfer matrix can be used to obtain transmittance and reflectance spectra of finite periodic structures as well as eigenmodes of infinite structures. Traditionally, calculation of the transfer matrix is performed in the frequency domain and involves linear algebra. In this work, we present a technique for calculation of the transfer matrix using the finite-difference time-domain (FDTD) method and show the way of its implementation in FDTD code. To illustrate the performance of our technique we calculate the transmittance spectra for opal photonic crystal slabs consisting of multiple layers of spherical scatterers. Our technique can be used for photonic band structure calculations. It can also be combined with existing FDTD methods for the analysis of periodic structures at an oblique incidence, as well as for modeling point sources in a periodic environment. PMID:24329377

  2. Practitioners' Perceptions of the Soccer Extra-Time Period: Implications for Future Research

    PubMed Central

    Harper, Liam D.; Fothergill, Melissa; West, Daniel J.; Stevenson, Emma; Russell, Mark

    2016-01-01

    Qualitative research investigating soccer practitioners’ perceptions can allow researchers to create practical research investigations. The extra-time period of soccer is understudied compared to other areas of soccer research. Using an open-ended online survey containing eleven main and nine sub questions, we gathered the perceptions of extra-time from 46 soccer practitioners, all working for different professional soccer clubs. Questions related to current practices, views on extra-time regulations, and ideas for future research. Using inductive content analysis, the following general dimensions were identified: ‘importance of extra-time’, ‘rule changes’, ‘efficacy of extra-time hydro-nutritional provision’, ‘nutritional timing’, ‘future research directions’, ‘preparatory modulations’ and ‘recovery’. The majority of practitioners (63%) either agreed or strongly agreed that extra-time is an important period for determining success in knockout football match-play. When asked if a fourth substitution should be permitted in extra-time, 67% agreed. The use of hydro-nutritional strategies prior to extra-time was predominately considered important or very important. However; only 41% of practitioners felt that it was the most important time point for the use of nutritional products. A similar number of practitioners account (50%) and do not (50%) account for the potential of extra-time when training and preparing players and 89% of practitioners stated that extra-time influences recovery practices following matches. In the five minute break prior to extra-time, the following practices (in order of priority) were advocated to players: hydration, energy provision, massage, and tactical preparations. Additionally, 87% of practitioners advocate a particular nutritional supplementation strategy prior to extra-time. In order of importance, practitioners see the following as future research areas: nutritional interventions, fatigue responses

  3. Simple Cognitive and Behavioural Changes Resulting from Improved Physical Fitness in Persons over 50 Years of Age.

    ERIC Educational Resources Information Center

    Stacey, C.; And Others

    1985-01-01

    Evaluates the effects of exercise on simple cognitive performance and on psychological well-being in persons over 50 years of age. It also assesses the relationship between a set of subject variables and dropout from fitness programs. Results suggest that the beneficial effects of exercise may extend to cognitive and personality processes.…

  4. Implementing principles of the integrated control concept 50 years later – current challenges in IPM for arthropod pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 1959 publication of the article ‘The Integrated Control Concept’ by Stern and colleagues established a new philosophical framework for pest management that eventually provided a foundation for IPM to develop. Considered within the context of pest control approaches 50 years ago, the integrated ...

  5. Concentration of hydrogen ions in several calcium hydroxide pastes over different periods of time.

    PubMed

    Vianna, Morgana Eli; Zilio, Danila M; Ferraz, Caio Cezar Randi; Zaia, Alexandre Augusto; de Souza-Filho, Francisco José; Gomes, Brenda Paula Figueiredo de Almeida

    2009-01-01

    The purpose of this in vitro study was to measure the concentration of hydrogen ions (pH) of calcium hydroxide [(Ca(OH)2] pastes combined with different vehicles over 7 periods of time. The Ca(OH)2 was manipulated with the following vehicles: i: sterile water; ii: iodoform plus sterile water; iii: local anesthetics (Lydocaine 2% with 1: 100,000 epinephrine); iv: polyethyleneglycol; v: glycerin; vi: 2.0% chlorhexidine gel; vii: camphorated paramonochlorophenol (CMCP); viii: (CMCP) + glycerin; and ix: polyethyleneglycol plus CMCP. The pastes were made on a glass plate to toothpaste consistency and the pH was measured at the following times: 5 min, 1, 24, 48 h; 7, 14 and 28 days. The data were statistically analyzed (Kruskal-Wallis at p<0.05). At 5 min, 1 and 24 h, the pH of all tested pastes ranged from 13.05 to 11.16. At 48 h and 7 days the pH of all tested pastes ranged from 11.66 to 8.92. At 14 and 28 days almost all pastes had pH means lower than 10. In conclusion, the mean pH of all tested calcium hydroxide pastes decreased with the time. Pastes made with aqueous vehicles (especially with sterile water), followed by oily vehicles (especially with CMCP + glycerin), held the highest pH means over the periods of time tested. PMID:20126906

  6. Dynamics of rock glaciers and debris-covered glaciers in the Central Chilean Andes over the last 50 years

    NASA Astrophysics Data System (ADS)

    Bodin, Xavier; Brenning, Alexander; Rojas Marchini, Fernanda

    2010-05-01

    In the semiarid Central Andes of Chile at 33.5°S., mountain permafrost is widely present above 3500-4000 m asl, especially in the form of rock glaciers, which often coexist with glaciers and debris-covered glaciers. This peculiar configuration of the cryosphere involves complex and poorly known responses of its components to climate change. Our study area in the Laguna Negra catchment is part of a watershed that provides up to two-thirds of the drinking water supplies to Chile's capital Santiago (5.5 million inhabitants) during the dry summer months. The 35 km² watershed contains 2.3 km² of uncovered glaciers, 0.9 km² of debris-covered glacier area and 4.3 km² of rock glaciers, and hosts the longest series of glacier mass balance measurement in Chile (Echaurren Norte glacier). Using orthorectified aerial photographs of 1956 and 1996 and a high resolution satellite image of 2008, we mapped the geometric changes that affected the glacier and the debris-covered glacier of the Punta Negra sub-catchment during the last 50 years. Surface displacements and volume changes were estimated based on 1956 and 1996 digital elevation models (DEMs), and the total loss of water equivalent in the catchment was quantified. At a shorter time scale, rock glaciers and a debris-covered glacier are being monitored since 2004, providing insights into their kinematics and near-surface thermal regime. The orthophotos reveal a 44.7% reduction of the uncovered glacier area between 1955 and 1996, and only small surface changes between 1996 and 2008. The volume reduction of both uncovered and debris-covered glaciers is estimated at at least 3.9 million m3 water equivalent between 1955 and 1996. The second noticeable change is the growth of the thermokarst areas on the debris-covered glacier, with the formation of new and the widening and deepening of existing melt-out depressions between 1955 and 2008. The thermal monitoring revealed that, in 2003/04, the mean annual ground surface

  7. Performance of ROB's near real-time ionospheric product during normal and disturbed space weather periods.

    NASA Astrophysics Data System (ADS)

    Bergeot, Nicolas; Chevalier, Jean-Marie; Bruyninx, Carine

    2015-04-01

    Several agencies are routinely monitoring the vertical Total Electron Content (vTEC) using GNSS data. Derived maps are available with different latencies, area extents, and grid/time resolutions. However, no high-resolution maps are publically available over Europe in near real-time. In this frame, the Royal Observatory of Belgium (ROB) developed the ROB-IONO software which takes advantage of the dense EUREF Permanent GNSS Network (EPN) to monitor the ionosphere. The main ROB products consist of ionospheric vTEC maps over Europe and their variability estimated in near real-time every 15 min on 0.5° x 0.5° grids using GPS observations. The maps are available online with a latency of ~3 min in the IONEX format at ftp://gnss.oma.be and as interactive web pages at www.gnss.be. During normal ionospheric activity, the ROB-TEC maps show a good agreement with widely used post-processed global products from IGS, CODE and ESA, with mean differences of 1.3 ± 0.9, 0.6 ± 0.7 and 0.4 ± 1.6 TECu respectively for the period 2012 to mid-2013. For a disturbed period, such as the 2003 Halloween ionospheric storm, the mean differences with IGS, CODE and ESA maps are respectively 0.9 ± 2.2, 0.1 ± 2.0 and 0.6 ± 6.8 TECu, with maximum differences (>38 TECu) occurring during the major phase of the storm. These differences are due to the lower resolution of global products in time and space compared to the ROB-TEC maps. A description of two recent events, on March 17, 2013 and February 27, 2014 highlights the capability of the method adopted to detect in near real-time abnormal ionospheric behaviour over Europe. The potential of the variability maps as an indicator of rapid ionospheric variations during the 15 min of observations is also highlighted. More than 30 ionospheric events associated with Space weather were detected during the period 2012-2014. The ionospheric perturbations are associated with Coronal Mass Ejections (CMEs, ~70% of the time), active geomagnetic conditions

  8. Dynamic effective properties of heterogeneous geological formations with spherical inclusions under periodic time variations

    NASA Astrophysics Data System (ADS)

    Rabinovich, A.; Dagan, G.; Miloh, T.

    2013-04-01

    In unsteady groundwater flow (or similar processes of heat/electrical conduction), the heterogeneous medium structure is characterized by two random properties, the conductivity K and the specific storativity S. The average head field ⟨H ⟩and the associated effective properties Kef, Sef are determined for a layer with a periodic head drop between boundaries, such that H is periodic in time, and a medium made up of a matrix with a dilute concentration of spherical inclusions. In the common quasi-steady approximation, Kef is equal to the classical steady solution while Sef = SA, the arithmetic mean. We derive expressions for the frequency dependent Kef, Sef, which are generally complex, i.e., dynamic. The main result is the delineation of the ranges of the parameters: dimensionless frequency (ω) and contrasts of conductivity (κ) and storativity (s) between the matrix and the inclusions, for which dynamic effects are significant.

  9. Ultrafast time dynamics studies of periodic lattices with free electron laser radiation

    SciTech Connect

    Quevedo, W.; Busse, G.; Hallmann, J.; More, R.; Petri, M.; Rajkovic, I.; Krasniqi, F.; Rudenko, A.; Tschentscher, T.; Stojanovic, N.; Duesterer, S.; Treusch, R.; Tolkiehn, M.; Techert, S.

    2012-11-01

    It has been proposed that radiation from free electron laser (FEL) at Hamburg (FLASH) can be used for ultrafast time-resolved x-ray diffraction experiments based on the near-infrared (NIR) pump/FEL probe scheme. Here, investigation probing the ultrafast structural dynamics of periodic nano-crystalline organic matter (silver behenate) with such a scheme is reported. Excitation with a femtosecond NIR laser leads to an ultrafast lattice modification which time evolution has been studied through the scattering of vacuum ultraviolet FEL pulses. The found effect last for 6 ps and underpins the possibility for studying nanoperiodic dynamics down to the FEL source time resolution. Furthermore, the possibility of extending the use of silver behenate (AgBh) as a wavelength and temporal calibration tool for experiments with soft x-ray/FEL sources is suggested.

  10. Evaluation of indoor air composition time variation in air-tight occupied spaces during night periods

    NASA Astrophysics Data System (ADS)

    Markov, Detelin

    2012-11-01

    This paper presents an easy-to-understand procedure for prediction of indoor air composition time variation in air-tight occupied spaces during the night periods. The mathematical model is based on the assumptions for homogeneity and perfect mixing of the indoor air, the ideal gas model for non-reacting gas mixtures, mass conservation equations for the entire system and for each species, a model for prediction of basal metabolic rate of humans as well as a model for prediction of O2 consumption rate and both CO2 and H2O generation rates by breathing. Time variation of indoor air composition is predicted at constant indoor air temperature for three scenarios based on the analytical solution of the mathematical model. The results achieved reveal both the most probable scenario for indoor air time variation in air-tight occupied spaces as well as the cause for morning tiredness after having a sleep in a modern energy efficient space.

  11. Time-headway distribution for periodic totally asymmetric exclusion process with various updates

    NASA Astrophysics Data System (ADS)

    Hrabák, P.; Krbálek, M.

    2016-03-01

    The totally asymmetric exclusion process (TASEP) with periodic boundaries is considered as traffic flow model. The large-L approximation of the stationary state is used for the derivation of the time-headway distribution (an important microscopic characteristic of traffic flow) for the model with generalized update (genTASEP) in both, forward- and backward-sequential representations. The usually used updates, fully-parallel and regular forward- and backward-sequential, are analyzed as special cases of the genTASEP. It is shown that only for those cases, the time-headway distribution is determined by the flow regardless to the density. The qualitative comparison of the results with traffic data demonstrates that the genTASEP with backward order and attractive interaction evinces similar properties of time-headway distribution as the real traffic sample.

  12. Timing and periodicity of paraglacial rock-slope failures in the Scottish Highlands

    NASA Astrophysics Data System (ADS)

    Ballantyne, Colin K.; Stone, John O.

    2013-03-01

    Many formerly-glaciated mountains exhibit a high density of postglacial rock-slope failures (RSFs) in the form of rockslides, rock avalanches or deep-seated gravitational slope deformations. Such RSFs are often termed 'paraglacial' as they reflect pre-conditioning by glaciation and deglaciation. The temporal pattern of paraglacial RSFs is unknown. We employ 47 cosmogenic isotope exposure ages obtained for 17 catastrophic RSFs in the Scottish Highlands to test models of changes in RSF frequency since deglaciation. Our results show that RSF activity spans almost the entire postglacial period from ~ 17 ka until ~ 1.5 ka, and that the periodicity of sampled postglacial RSFs is statistically indistinguishable from a pattern of uniform periodicity (~ 1 ka- 1). Our data do not conform to proposed models of declining RSF frequency with time elapsed since deglaciation, but suggest that the temporal distribution of postglacial RSFs is best described by a combination of rapid response (enhanced RSF frequency during or immediately after deglaciation) followed by approximately constant periodicity. Our findings are consistent with near-surface fracturing of rock when glacially-induced confining stresses are removed, causing some failures during or immediately after deglaciation and reducing other slopes to critical conditional stability so that failure is triggered by progressive rock-mass weakening or by transient triggering mechanisms. Neither permafrost degradation (thaw of ice in joints) nor seismic activity offers a general explanation for triggering Scottish RSFs, but could be contributory in some cases. The quasi-constant periodicity inferred for Holocene RSFs implies that the probability of RSFs in this seismically-quiescent intraplate area has not changed in the past ~ 10 ka, and that further (though infrequent) catastrophic RSFs are likely to occur in the future.

  13. Time-Periodic Solutions of Driven-Damped Trimer Granular Crystals

    DOE PAGESBeta

    Charalampidis, E. G.; Li, F.; Chong, C.; Yang, J.; Kevrekidis, P. G.

    2015-01-01

    We consider time-periodic structures of granular crystals consisting of alternate chrome steel (S) and tungsten carbide (W) spherical particles where each unit cell follows the pattern of a 2 : 1 trimer: S-W-S. The configuration at the left boundary is driven by a harmonic in-time actuation with given amplitude and frequency while the right one is a fixed wall. Similar to the case of a dimer chain, the combination of dissipation, driving of the boundary, and intrinsic nonlinearity leads to complex dynamics. For fixed driving frequencies in each of the spectral gaps, we find that the nonlinear surface modes and the statesmore » dictated by the linear drive collide in a saddle-node bifurcation as the driving amplitude is increased, beyond which the dynamics of the system becomes chaotic. While the bifurcation structure is similar for solutions within the first and second gap, those in the first gap appear to be less robust. We also conduct a continuation in driving frequency, where it is apparent that the nonlinearity of the system results in a complex bifurcation diagram, involving an intricate set of loops of branches, especially within the spectral gap. The theoretical findings are qualitatively corroborated by the experimental full-field visualization of the time-periodic structures.« less

  14. A Statistical Analysis of 50 Years of Daily Solar Wind Velocity Data

    NASA Astrophysics Data System (ADS)

    LI, K. J.; ZHANNG, J.; FENG, W.

    2016-05-01

    Daily mean value of solar wind velocity measured by various spacecraft near the Earth’s orbit from 1963 November 27 to 2013 December 31 given by OMNIWeb is utilized to investigate its characteristics through statistical analyses. The percent probability distribution of solar wind velocity can be described well by the Γ distribution function with the most probable velocity to be 373 {km} {{{s}}}-1. It is found that solar wind could be statistically classified into three groups: (1) the low-velocity wind, v\\lt 450 {km} {{{s}}}-1, which positively responds to, and in the cycle phase lags, the solar activity cycle; (2) the high-velocity wind, 450≤slant v\\lt 725 {km} {{{s}}}-1, which negatively responds to, and in the cycle phase leads, the solar activity cycle, but in a short timescale (one-rotation-period) lags the solar activity cycle; and (3) the extreme-high-velocity wind, v≥slant 725 {km} {{{s}}}-1, which positively responds to, and in cycle phase leads, the solar activity cycle. A period of about 27 days is determined for solar wind in the first two groups, so that solar wind in the groups is modulated by the solar rotation and related with solar long-life magnetic structures. Solar wind of extreme high velocity appears mainly at the descending phases of the solar cycles.

  15. Hydromagnetic natural convection flow between vertical parallel plates with time-periodic boundary conditions

    NASA Astrophysics Data System (ADS)

    Adesanya, S. O.; Oluwadare, E. O.; Falade, J. A.; Makinde, O. D.

    2015-12-01

    In this paper, the free convective flow of magnetohydrodynamic fluid through a channel with time periodic boundary condition is investigated by taking the effects of Joule dissipation into consideration. Based on simplifying assumptions, the coupled governing equations are reduced to a set of nonlinear boundary valued problem. Approximate solutions are obtained by using semi-analytical Adomian decomposition method. The effect of pertinent parameters on the fluid velocity, temperature distribution, Nusselt number and skin friction are presented graphically and discussed. The result of the computation shows that an increase in the magnetic field intensity has significant influence on the fluid flow.

  16. The Cluster Science Archive: from Time Period to Physics Based Search

    NASA Astrophysics Data System (ADS)

    Masson, A.; Escoubet, C. P.; Laakso, H. E.; Perry, C. H.

    2015-12-01

    Since 2000, the Cluster spacecraft relay the most detailed information on how the solar wind affects our geospace in three dimensions. Science output from Cluster is a leap forward in our knowledge of space plasma physics: the science behind space weather. It has been key in improving the modeling of the magnetosphere and understanding its various physical processes. Cluster data have enabled the publication of more than 2000 refereed papers and counting. This substantial scientific return is often attributed to the online availability of the Cluster data archive, now called the Cluster Science Archive (CSA). It is being developed by the ESAC Science Data Center (ESDC) team and maintained alongside other science ESA archives at ESAC (ESA Space Astronomy Center, Madrid, Spain). CSA is a public archive, which contains the entire set of Cluster high-resolution data, and other related products in a standard format and with a complete set of metadata. Since May 2015, it also contains data from the CNSA/ESA Double Star mission (2003-2008), a mission operated in conjunction with Cluster. The total amount of data format now exceeds 100 TB. Accessing CSA requires to be registered to enable user profiles and CSA accounts more than 1,500 users. CSA provides unique tools for visualizing its data including - on-demand particle distribution functions visualization - fast data browsing with more than 15TB of pre-generated plots - inventory plots It also offers command line capabilities (e.g. data access via Matlab or IDL softwares, data streaming). Despite its reliability, users can only request data for a specific time period while scientists often focus on specific regions or data signatures. For these reasons, a data-mining tool is being developed to do just that. It offers an interface to select data based not only on a time period but on various criteria including: key physical parameters, regions of space and spacecraft constellation geometry. The output of this tool is a

  17. Geometric tools for solving the FDI problem for linear periodic discrete-time systems

    NASA Astrophysics Data System (ADS)

    Longhi, Sauro; Monteriù, Andrea

    2013-07-01

    This paper studies the problem of detecting and isolating faults in linear periodic discrete-time systems. The aim is to design an observer-based residual generator where each residual is sensitive to one fault, whilst remaining insensitive to the other faults that can affect the system. Making use of the geometric tools, and in particular of the outer observable subspace notion, the Fault Detection and Isolation (FDI) problem is formulated and necessary and solvability conditions are given. An algorithmic procedure is described to determine the solution of the FDI problem.

  18. Thermomagnetic convection in a ferrofluid layer exposed to a time-periodic magnetic field

    NASA Astrophysics Data System (ADS)

    Matura, P.; Lücke, M.

    2009-08-01

    We have investigated the influence of a time-periodic and spatially homogeneous magnetic field on the linear stability properties and on the nonlinear response of a ferrofluid layer heated from below and from above. A competition between stabilizing thermal and viscous diffusion and destabilizing buoyancy and Kelvin forces occurs. Floquet theory is used to determine the stability boundaries of the motionless conductive state for a harmonic and subharmonic response. Full numerical simulations with a finite difference method were made to obtain nonlinear convective states. The effect of low- and high-frequency modulation on the stability boundaries as well as on the nonlinear oscillations that may occur is investigated.

  19. Time series modelling of increased soil temperature anomalies during long period

    NASA Astrophysics Data System (ADS)

    Shirvani, Amin; Moradi, Farzad; Moosavi, Ali Akbar

    2015-10-01

    Soil temperature just beneath the soil surface is highly dynamic and has a direct impact on plant seed germination and is probably the most distinct and recognisable factor governing emergence. Autoregressive integrated moving average as a stochastic model was developed to predict the weekly soil temperature anomalies at 10 cm depth, one of the most important soil parameters. The weekly soil temperature anomalies for the periods of January1986-December 2011 and January 2012-December 2013 were taken into consideration to construct and test autoregressive integrated moving average models. The proposed model autoregressive integrated moving average (2,1,1) had a minimum value of Akaike information criterion and its estimated coefficients were different from zero at 5% significance level. The prediction of the weekly soil temperature anomalies during the test period using this proposed model indicated a high correlation coefficient between the observed and predicted data - that was 0.99 for lead time 1 week. Linear trend analysis indicated that the soil temperature anomalies warmed up significantly by 1.8°C during the period of 1986-2011.

  20. Periodic boundary conditions for long-time nonequilibrium molecular dynamics simulations of incompressible flows

    NASA Astrophysics Data System (ADS)

    Dobson, Matthew

    2014-11-01

    This work presents a generalization of the Kraynik-Reinelt (KR) boundary conditions for nonequilibrium molecular dynamics simulations. In the simulation of steady, homogeneous flows with periodic boundary conditions, the simulation box deforms with the flow, and it is possible for image particles to become arbitrarily close, causing a breakdown in the simulation. The KR boundary conditions avoid this problem for planar elongational flow and general planar mixed flow [T. A. Hunt, S. Bernardi, and B. D. Todd, J. Chem. Phys. 133, 154116 (2010)] through careful choice of the initial simulation box and by periodically remapping the simulation box in a way that conserves image locations. In this work, the ideas are extended to a large class of three-dimensional flows by using multiple remappings for the simulation box. The simulation box geometry is no longer time-periodic (which was shown to be impossible for uniaxial and biaxial stretching flows in the original work by Kraynik and Reinelt [Int. J. Multiphase Flow 18, 1045 (1992)]. The presented algorithm applies to all flows with nondefective flow matrices, and in particular, to uniaxial and biaxial flows.

  1. Symbolic dynamics of pulse transit time and heart period in children with upper airway obstruction.

    PubMed

    Baumert, Mathias; Kohler, Mark; Pamula, Yvonne; Immanuel, Sarah A

    2015-08-01

    Upper airway obstruction (UAO) is a relatively common condition during childhood that is characterized by periods of partial or complete upper airway closure, resulting in restless sleep. It has also been suggested that UAO triggers early cardiovascular changes that may predispose to an increased risk of developing cardiovascular diseases later in life. The aim of this study was to assess the temporal dynamics of heart period (HP) and pulse transit time (PTT) during quite, event-free periods of sleep in children with UAO (n = 40) and matched healthy controls. The dynamics of HP and PTT were symbolized based on the sextiles of their distribution and words of length three were formed and classified into four types based on their patterns. Joint symbolic dynamics represent the concomitant occurrence of words in HP and PTT. Children with UAO showed a significantly increased frequency in word types of monotonously increasing and decreasing HP and PTT as well as joint dynamics across all stages of sleep. The dynamics of HP showed a marked sleep stage dependence, while PTT dynamics appeared to be relatively unaffected. In conclusion, cardiovascular dynamics are altered in children with UAO during scored event-free sleep, indicative of frequent bursts in sympathetic nervous system activity, possibly reflecting subcortical arousal responses to brief and subtle increases in UAO. PMID:26736629

  2. Lucid dreaming incidence: A quality effects meta-analysis of 50years of research.

    PubMed

    Saunders, David T; Roe, Chris A; Smith, Graham; Clegg, Helen

    2016-07-01

    We report a quality effects meta-analysis on studies from the period 1966-2016 measuring either (a) lucid dreaming prevalence (one or more lucid dreams in a lifetime); (b) frequent lucid dreaming (one or more lucid dreams in a month) or both. A quality effects meta-analysis allows for the minimisation of the influence of study methodological quality on overall model estimates. Following sensitivity analysis, a heterogeneous lucid dreaming prevalence data set of 34 studies yielded a mean estimate of 55%, 95% C. I. [49%, 62%] for which moderator analysis showed no systematic bias for suspected sources of variability. A heterogeneous lucid dreaming frequency data set of 25 studies yielded a mean estimate of 23%, 95% C. I. [20%, 25%], moderator analysis revealed no suspected sources of variability. These findings are consistent with earlier estimates of lucid dreaming prevalence and frequent lucid dreaming in the population but are based on more robust evidence. PMID:27337287

  3. [50 years WATL (Scientific Working Group for the Therapy of Lung Diseases)].

    PubMed

    Wirtz, H; Kropp, R; Behr, J; Costabel, U; Bonnet, R; Schönfeld, N; Prasse, A; Kardos, P; Seehausen, V; Loddenkemper, R

    2014-03-01

    On the occasion of the 50th anniversary of the Scientific Working Group for the Therapy of Lung Diseases (WATL) the history is described from its foundation to the present situation. Research topics during this long period are specified and the studies are briefly outlined. In the beginning, WATL was engaged mainly in studies on tuberculosis, later on, the spectrum of WATL was broadened considerably to diseases like sarcoidosis, pulmonary Langerhans' cell histiocytosis, pulmonary emphysema due to α1-antitrypsin deficiency, chronic obstructive bronchitis and bronchial asthma as well as nontuberculous mycobacterioses. Finally, realising that the methodological capabilities of WATL were not sufficient to conduct large trials in classical lung diseases considering current requirements, WATL has begun to acquire competence in rare lung diseases such as lymphangioleiomyomatosis and alveolar proteinosis. In addition, WATL is dedicated to educative aims by organising conferences on topics which are not part of main stream respiratory medicine. PMID:24595854

  4. Respiratory rate: measurement of variability over time and accuracy at different counting periods.

    PubMed Central

    Simoes, E A; Roark, R; Berman, S; Esler, L L; Murphy, J

    1991-01-01

    The respiratory rates/minute of 97 children were monitored every 10-15 minutes over one hour, by an observer and by pneumogram, at which times two 30 second and one 60 second counts were obtained. The children were under 5 years of age with lower respiratory tract infections (n = 20), upper respiratory tract infections (n = 34), or controls without acute respiratory infection (n = 43). The difference between respiratory rate count determined simultaneously by observation and pneumogram in relation to their mean count was analysed for the 60 second counting period, 30 plus 30 second period, and the 30 second period doubled. The mean difference for the 60 second period was 1.79, for the 30 plus 30 second period 1.42, and for the 30 second period doubled 1.72. The variability between respiratory rate counts determined by observation and pneumogram was significantly lower in counts obtained when the subject was sleeping and higher when agitated compared with obtaining a count when the subject was awake and calm or feeding. The variability was also significantly lower in subjects with lower respiratory tract infections compared with those with upper respiratory tract infections and control subjects without respiratory symptoms. In the same patient, over the one hour, 50% of the 60 second counts varied by up to 14 breaths/minute and 75% by up to 21 breaths/minute. The least variability was seen in children with a lower respiratory tract infection, who tended to maintain their rapid breathing in contrast to those with an upper respiratory tract infection and controls without respiratory symptoms. About 10% of initial 30 second counts, 12% of 60 second, and 16% of initial and repeat 30 second attempts to obtain accurate counts failed. Failures occurred more frequently in children <2 months of age and those agitated. The data from this study suggest that one minute's counting either at a stretch or in two blocks of 30 second intervals is better than counting the respiratory

  5. Time-dependent Mott transition in the periodic Anderson model with nonlocal hybridization

    NASA Astrophysics Data System (ADS)

    Hofmann, Felix; Potthoff, Michael

    2016-08-01

    The time-dependent Mott transition in a periodic Anderson model with off-site, nearest-neighbor hybridization is studied within the framework of nonequilibrium self-energy functional theory. Using the two-site dynamical-impurity approximation, we compute the real-time dynamics of the optimal variational parameter and of different observables initiated by sudden quenches of the Hubbard-U and identify the critical interaction. The time-dependent transition is orbital selective, i.e., in the final state, reached in the long-time limit after the quench to the critical interaction, the Mott gap opens in the spectral function of the localized orbitals only. We discuss the dependence of the critical interaction and of the final-state effective temperature on the hybridization strength and point out the various similarities between the nonequilibrium and the equilibrium Mott transition. It is shown that these can also be smoothly connected to each other by increasing the duration of a U-ramp from a sudden quench to a quasi-static process. The physics found for the model with off-site hybridization is compared with the dynamical Mott transition in the single-orbital Hubbard model and with the dynamical crossover found for the real-time dynamics of the conventional Anderson lattice with on-site hybridization.

  6. Tracking rhythmicity in nonstationary quasi-periodic biomedical signals using adaptive time-varying covariance.

    PubMed

    Li, Dan; Jung, Ranu

    2002-07-01

    A time-varying covariance method for detecting and quantifying the evolution of rhythmicity (frequency) in persistently varying quasi-periodic nonstationary signals is presented. The basic method, evaluated using chirp signals, utilizes a shifting window of fixed length. A substantial reduction in estimation bias and variability are obtained by utilizing an adaptive window whose length is dependent on past frequency estimates. The adaptive window yields estimates that are comparable in accuracy to those obtained using high-resolution time-frequency representation but with lower computation requirements and the potential for on-line application. Finally, an example of the application of the method for analyzing a neural recording is also illustrated. PMID:11931864

  7. Spectral factorization in periodically time-varying systems and application to navigation problems.

    NASA Technical Reports Server (NTRS)

    Nishimura, T.

    1972-01-01

    Spectral factorization has been used previously to derive the steady-state solution of Kalman filtering equations without iteration for constant coefficient systems. The present work extends the spectral factorization algorithm to time-varying systems having periodic coefficient matrices for cases of both discrete and continuous systems. Time-consuming, expensive iterations of sequential covariance equations are not required to reach the final solution since this is an algebraic algorithm employing existing eigenvalue, eigenvector subroutines. The computer program incorporating the algorithm is suitable for sensitivity studies in formulating navigation and guidance strategies of low-thrust interplanetary missions. The determination of an optimum tracking pattern from an earth station is examined as an example.

  8. Nonlinear time-periodic models of the longitudinal flight dynamics of desert locusts Schistocerca gregaria

    PubMed Central

    Taylor, Graham K; Żbikowski, Rafał

    2005-01-01

    Previous studies of insect flight control have been statistical in approach, simply correlating wing kinematics with body kinematics or force production. Kinematics and forces are linked by Newtonian mechanics, so adopting a dynamics-based approach is necessary if we are to place the study of insect flight on its proper physical footing. Here we develop semi-empirical models of the longitudinal flight dynamics of desert locusts Schistocerca gregaria. We use instantaneous force–moment measurements from individual locusts to parametrize the nonlinear rigid body equations of motion. Since the instantaneous forces are approximately periodic, we represent them using Fourier series, which are embedded in the equations of motion to give a nonlinear time-periodic (NLTP) model. This is a proper mathematical generalization of an earlier linear-time invariant (LTI) model of locust flight dynamics, developed using previously published time-averaged versions of the instantaneous force recordings. We perform various numerical simulations, within the fitted range of the model, and across the range of body angles used by free-flying locusts, to explore the likely behaviour of the locusts upon release from the tether. Solutions of the NLTP models are compared with solutions of the nonlinear time-invariant (NLTI) models to which they reduce when the periodic terms are dropped. Both sets of models are unstable and therefore fail to explain locust flight stability fully. Nevertheless, whereas the measured forces include statistically significant harmonic content up to about the eighth harmonic, the simulated flight trajectories display no harmonic content above the fundamental forcing frequency. Hence, manoeuvre control in locusts will not directly reflect subtle changes in the higher harmonics of the wing beat, but must operate on a coarser time-scale. A state-space analysis of the NLTP models reveals orbital trajectories that are impossible to capture in the LTI and NLTI models

  9. Journal of Biological Education: A Personal Reflection on Its First 50 Years

    ERIC Educational Resources Information Center

    Reiss, Michael J.

    2016-01-01

    In this commentary, Michael Reiss describes his time with the "Journal of Biology Education" ("JBE") dating back to 1984 when the journal published his first article (Reiss 1984). Over the years, Reiss has authored 31 "JBE" pieces (excluding reviews) including one in honor of the journal's 25th anniversary (Reiss…

  10. Family Diversity in 50 Years of Storybook Images of Family Life.

    ERIC Educational Resources Information Center

    Rodman, Nancy M.; Hildreth, Gladys J.

    2002-01-01

    Content analysis of a sample of 100 picture storybooks about family life published 1943-1993 reveals no significant differences in the frequency of appearance of different family types or ethnicities over time. Dominant images remained the nuclear (63%) and Caucasian (67%) family. (Contains 37 references.) (SK)

  11. Changes in cotton gin energy use over the past 50 years

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The public is concerned about environmental quality and energy sustainability. Cotton producers, gin owners and plant managers are concerned about rising energy prices. Both have an interest in current cotton gin energy consumption, and may also be interested in how it has changed over time. Informa...

  12. Teaching of astrophysics at the University of Bucharest, Romania, in the last 50 years

    NASA Astrophysics Data System (ADS)

    Rusu, Mircea; Stavinschi, Magda

    2007-03-01

    In the University of Bucharest, by tradition, Astronomy was developed within the Department of Mechanics dominated by outstanding mathematicians. From this reason, for a long time, Astronomy was sustained mainly in the Faculty of Mathematics. Some lectures were given in the Faculty of Physics, too. After 1990, the astrophysics became a systematic course at the Faculty of Physics, and gradually the number of topics studied increased. In a relatively short time, reasonably good results were obtained, being now involved in many international cooperations in astrophysics, giving master degree in astrophysics to the Romanian students. During this time the Faculty of Physics of Bucharest University was and still is involved in many European programs, like TEMPUS and ERASMUS/SOCRATES (with: France, Germany, Italy, Greece) and with other countries, as USA or Australia, on specific fields of astrophysics. The Faculty organized for the first time the observation of a total solar eclipse (TSE 1999), when it hosted the 24-th ISYA Summer School. We would like to emphasize here the main aspects of those activities, and their perspectives for the next future.

  13. Period-independent novel circadian oscillators revealed by timed exercise and palatable meals

    PubMed Central

    Flôres, Danilo E. F. L.; Bettilyon, Crystal N.; Yamazaki, Shin

    2016-01-01

    The mammalian circadian system is a hierarchical network of oscillators organized to optimally coordinate behavior and physiology with daily environmental cycles. The suprachiasmatic nucleus (SCN) of the hypothalamus is at the top of this hierarchy, synchronizing to the environmental light-dark cycle, and coordinates the phases of peripheral clocks. The Period genes are critical components of the molecular timekeeping mechanism of these clocks. Circadian clocks are disabled in Period1/2/3 triple mutant mice, resulting in arrhythmic behavior in constant conditions. We uncovered rhythmic behavior in this mutant by simply exposing the mice to timed access to a palatable meal or running wheel. The emergent circadian behavior rhythms free-ran for many cycles under constant conditions without cyclic environmental cues. Together, these data demonstrate that the palatable meal-inducible circadian oscillator (PICO) and wheel-inducible circadian oscillator (WICO) are generated by non-canonical circadian clocks. Entrainment of these novel oscillators by palatable snacks and timed exercise could become novel therapeutics for human conditions caused by disruptions of the circadian clocks. PMID:26904978

  14. Period-independent novel circadian oscillators revealed by timed exercise and palatable meals.

    PubMed

    Flôres, Danilo E F L; Bettilyon, Crystal N; Yamazaki, Shin

    2016-01-01

    The mammalian circadian system is a hierarchical network of oscillators organized to optimally coordinate behavior and physiology with daily environmental cycles. The suprachiasmatic nucleus (SCN) of the hypothalamus is at the top of this hierarchy, synchronizing to the environmental light-dark cycle, and coordinates the phases of peripheral clocks. The Period genes are critical components of the molecular timekeeping mechanism of these clocks. Circadian clocks are disabled in Period1/2/3 triple mutant mice, resulting in arrhythmic behavior in constant conditions. We uncovered rhythmic behavior in this mutant by simply exposing the mice to timed access to a palatable meal or running wheel. The emergent circadian behavior rhythms free-ran for many cycles under constant conditions without cyclic environmental cues. Together, these data demonstrate that the palatable meal-inducible circadian oscillator (PICO) and wheel-inducible circadian oscillator (WICO) are generated by non-canonical circadian clocks. Entrainment of these novel oscillators by palatable snacks and timed exercise could become novel therapeutics for human conditions caused by disruptions of the circadian clocks. PMID:26904978

  15. Short- and long-term forecast for chaotic and random systems (50 years after Lorenz's paper)

    NASA Astrophysics Data System (ADS)

    Bunimovich, Leonid A.

    2014-09-01

    We briefly review a history of the impact of the famous 1963 paper by E Lorenz on hydrodynamics, physics and mathematics communities on both sides of the iron curtain. This paper was an attempt to apply the ideas and methods of dynamical systems theory to the problem of weather forecast. Its major discovery was the phenomenon of chaos in dissipative dynamical systems which makes such forecasts rather problematic, if at all possible. In this connection we present some recent results which demonstrate that both a short-term and a long-term forecast are actually possible for the most chaotic dynamical (as well as for the most random, like IID and Markov chain) systems. Moreover, there is a sharp transition between the time interval where one may use a short-term forecast and the times where a long-term forecast is applicable. Finally we discuss how these findings could be incorporated into the forecast strategy outlined in the Lorenz's paper.

  16. Elucidating the Linkage Between Changes in Land Use, Atmospheric Mineral Dust Loading, and Precipitation in Central Asia During the Past 50-years

    NASA Astrophysics Data System (ADS)

    Sokolik, I. N.; Tatarskii, V. V.; Razuvaev, V. N.; Knight, R. W.; Enloe, J. G.

    2004-12-01

    It is believed that both land-use/land cover changes and atmospheric mineral dust are among the main factors controlling the precipitation and hydrological cycle. Over the past 50-years Central Asia has been undergoing major human-induced land-use changes that altered the geographical area and intensity of dust sources. Desiccation of the Aral Sea and conversion of the steppe in Kazakhstan to the agriculture fields are just a few examples of occurred land-use changes. Interactions of precipitation with land use changes and atmospheric dust can occur at a variety of scales through a poorly understood series of feedback mechanisms. This study addresses this issue by performing a detailed analysis of empirical data at a variety of spatial and temporal scales. The 50-year daily precipitation observations reported from ground-based stations in Central Asia were analyzed to 1) determine the changes in the precipitation distribution and trends and 2) elucidate the potential linkages between precipitation trends and land use and dust loading changes. Utilizing several statistical techniques, we analyzed the precipitation time series for the individual stations as well as for a subset of the stations considering different time-averaging. Several criteria were used to group the stations to separate those affected by dust transport and/or by same types of land-use changes. The consistency between observed precipitation trends and those predicted by the models will be discussed.

  17. Can changes in the distribution of lizard species over the past 50 years be attributed to climate change?

    NASA Astrophysics Data System (ADS)

    Wu, Jianguo

    2015-07-01

    We analyzed changes in the distributions of nine lizard species in China over the past 50 years and identified whether these changes could be attributed to climate change. Long-term records of lizard distributions, grey relational analysis, fuzzy set classification techniques, and attribution methods were used. The distribution of nearly half of the lizard species primarily shifted northward, westward, or eastward since the 1970s, and most changes were related to the thermal index. In response to climate change over the past 50 years, the distribution boundary and center of some species have mainly shifted northward, westward, or eastward, with some irregular shifting during the process. The observed and predicted changes in distribution were highly consistent for some lizard species. The changes in the northern and eastern distribution limits of nearly half of the lizard species and the western limits and distribution centers of several species can be attributed to climate change.

  18. Can changes in the distribution of lizard species over the past 50 years be attributed to climate change?

    NASA Astrophysics Data System (ADS)

    Wu, Jianguo

    2016-08-01

    We analyzed changes in the distributions of nine lizard species in China over the past 50 years and identified whether these changes could be attributed to climate change. Long-term records of lizard distributions, grey relational analysis, fuzzy set classification techniques, and attribution methods were used. The distribution of nearly half of the lizard species primarily shifted northward, westward, or eastward since the 1970s, and most changes were related to the thermal index. In response to climate change over the past 50 years, the distribution boundary and center of some species have mainly shifted northward, westward, or eastward, with some irregular shifting during the process. The observed and predicted changes in distribution were highly consistent for some lizard species. The changes in the northern and eastern distribution limits of nearly half of the lizard species and the western limits and distribution centers of several species can be attributed to climate change.

  19. Humid tropical rain forest has expanded into eucalypt forest and savanna over the last 50 years

    PubMed Central

    Tng, David Y P; Murphy, Brett P; Weber, Ellen; Sanders, Gregor; Williamson, Grant J; Kemp, Jeanette; Bowman, David M J S

    2012-01-01

    Tropical rain forest expansion and savanna woody vegetation thickening appear to be a global trend, but there remains uncertainty about whether there is a common set of global drivers. Using geographic information techniques, we analyzed aerial photography of five areas in the humid tropics of northeastern Queensland, Australia, taken in the 1950s and 2008, to determine if changes in rain forest extent match those reported for the Australian monsoon tropics using similar techniques. Mapping of the 1950s aerial photography showed that of the combined study area (64,430 ha), 63% was classified as eucalypt forests/woodland and 37% as rain forest. Our mapping revealed that although most boundaries remained stable, there was a net increase of 732 ha of the original rain forest area over the study period, and negligible conversion of rain forest to eucalypt forest/woodland. Statistical modeling, controlling for spatial autocorrelation, indicated distance from preexisting rain forest as the strongest determinant of rain forest expansion. Margin extension had a mean rate across the five sites of 0.6 m per decade. Expansion was greater in tall open forest types but also occurred in shorter, more flammable woodland vegetation types. No correlations were detected with other local variables (aspect, elevation, geology, topography, drainage). Using a geographically weighted mean rate of rain forest margin extension across the whole region, we predict that over 25% of tall open forest (a forest type of high conservation significance) would still remain after 2000 years of rain forest expansion. This slow replacement is due to the convoluted nature of the rain forest boundary and the irregular shape of the tall open forest patches. Our analyses point to the increased concentration of atmospheric CO2 as the most likely global driver of indiscriminate rain forest expansion occurring in northeastern Australia, by increasing tree growth and thereby overriding the effects of fire

  20. Patient Perspectives on Online Health Information and Communication With Doctors: A Qualitative Study of Patients 50 Years Old and Over

    PubMed Central

    2015-01-01

    Background As health care systems around the world shift toward models that emphasize self-care management, there is increasing pressure for patients to obtain health information online. It is critical that patients are able to identify potential problems with using the Internet to diagnose and treat a health issue and that they feel comfortable communicating with their doctor about the health information they acquire from the Internet. Objective Our aim was to examine patient-identified (1) problems with using the Internet to identify and treat a health issue, (2) barriers to communication with a doctor about online health information seeking, and (3) facilitators of communication with a doctor about patient searches for health information on the Internet. Methods For this qualitative exploratory study, semistructured interviews were conducted with a sample of 56 adults age 50 years old and over. General concerns regarding use of the Internet to diagnose and treat a health issue were examined separately for participants based on whether they had ever discussed health information obtained through the Internet with a doctor. Discussions about barriers to and facilitators of communication about patient searches for health information on the Internet with a doctor were analyzed using thematic analysis. Results Six higher-level general concerns emerged: (1) limitations in own ability, (2) credibility/limitations of online information, (3) anxiety, (4) time consumption, (5) conflict, and (6) non-physical harm. The most prevalent concern raised by participants who communicated with a doctor about their online health information seeking related to the credibility or limitations in online information. Participants who had never communicated with a doctor about their online health information seeking most commonly reported concerns about non-physical harm. Four barriers to communication emerged: (1) concerns about embarrassment, (2) concerns that the doctor doesn’t want

  1. The Rebirth of the Russian Space Program: 50 Years After Sputnik, New Frontiers

    NASA Astrophysics Data System (ADS)

    Watkins, Nick

    2008-07-01

    Every morning, I pass by a large poster in my stairwell of Soviet cosmonaut Yuri Gagarin, who in 1961 became the first person to orbit the Earth. On the poster, which my brother found in Central Asia, Gagarin's helmeted head merges into the curve of the Earth. The poster is a powerful reminder of a time when the Soviet space program was the envy of the world, and when it would have seemed to many people quite likely that by 2008 Soviet cosmonauts would be working on the Moon or be on their way to Mars.

  2. An observational study of comorbidity and healthcare utilisation among HIV-positive patients aged 50 years and over.

    PubMed

    Patel, Roshani; Moore, Thomas; Cooper, Vanessa; McArdle, Conor; Perry, Nicky; Cheek, Elizabeth; Gainsborough, Nicola; Fisher, Martin

    2016-07-01

    The number of HIV-positive people aged ≥50 years is rising each year. We measured the prevalence of non-infectious illnesses and their risk factors and described healthcare use in this UK population. A cross-sectional, observational study was conducted at an outpatient HIV specialist clinic in south east England. Patients age ≥50 years were invited to complete questionnaires measuring demographics, non-infectious illnesses, medication use, lifestyle and healthcare utilisation. The response rate was 67%. Of 299 participants, 84% reported ≥1 comorbid condition and 61% reported ≥2 (multimorbidity). Most commonly reported were high cholesterol, sexual dysfunction, hypertension and depression. In multivariate analyses, age, number of years HIV-positive and duration of antiretroviral therapy remained significant predictors of comorbidity when controlling for lifestyle factors (exercise, smoking and use of recreational drugs and alcohol). Use of non-HIV healthcare services was associated with increasing comorbidity, a longer duration of HIV and recreational drug use. The majority of HIV-patients aged ≥50 years reported multiple comorbidities and this was associated with polypharmacy and increased use of non-HIV services. Further research examining the quality, safety and patient experience of healthcare is needed to inform development of services to optimally meet the needs of older HIV-positive patients. PMID:26068965

  3. Detecting and Attributing the Effects of Climate Change on the Distributions of Snake Species Over the Past 50 Years

    NASA Astrophysics Data System (ADS)

    Wu, Jianguo

    2016-01-01

    It is unclear whether the distributions of snakes have changed in association with climate change over the past years. We detected the distribution changes of snakes over the past 50 years and determined whether the changes could be attributed to recent climate change in China. Long-term records of the distribution of nine snake species in China, grey relationship analysis, fuzzy sets classification techniques, the consistency index, and attributed methods were used. Over the past 50 years, the distributions of snake species have changed in multiple directions, primarily shifting northwards, and most of the changes were related to the thermal index. Driven by climatic factors over the past 50 years, the distribution boundary and distribution centers of some species changed with the fluctuations. The observed and predicted changes in distribution were highly consistent for some snake species. The changes in the northern limits of distributions of nearly half of the species, as well as the southern and eastern limits, and the distribution centers of some snake species can be attributed to climate change.

  4. Enhanced Transport of Passive Tracers In A Time Periodic Two-dimensional Flow

    NASA Astrophysics Data System (ADS)

    Boffetta, G.; Cencini, M.; Espa, S.; Musacchio, S.

    , investigating systems in which the second condition is violated is much more inter- esting. With this purpose, some experiments have shown how superdiffusion arises in a two-dimensional quasi-geostrophic (planetary-type) flow, where particles can jump for very long time in the same direction performing a Levy flight (Castiglione et al., 2001 ). Moreover, two recent papers (Vulpiani, 1998; Solomon, 2001) show how, also in very simple two-dimensional, time and space periodic cellular flows,anomalous diffusive behaviours can appear. In this paper we present an experimental study of transport in an electromagnetically forced time periodic two-dimensional flow. The flow is generated by applying an electromagnetic forcing on a thin layer of an elec- trolyte solution and reveals in a square grid of alternating vortices. Time dependence can be easily obtained by changing the time dependence of the electric fields. In par- ticular, considering certain values of the imposed oscillation frequencies, particles can display very long jump. Particle Tracking Velocimetry (PTV) is used to measure the flow field. This technique is the most suitable for studying dispersion phenomena in a Lagrangian framework allowing the direct evaluation of particle displacements and related quantities (Cenedese, Querzoli; 2000). Moreover, due to the characteristics of the analyzed flow and to the improvement of the tracking procedure, we have been able to track a great number of particles for time intervals greater than the charac- teristic time-scales of the flow. In order to characterize the time correlations we will evaluate the so-called jumps probabilities with memory which represent the probabil- ities to jump in a given direction conditioned to having experienced jumps in the same direction at previous times. Such statistics will revealed very useful and suitable for detecting the onset of the aforementioned correlations. 2

  5. Evolution of illustrations in anatomy: a study from the classical period in Europe to modern times.

    PubMed

    Ghosh, Sanjib Kumar

    2015-01-01

    Illustrations constitute an essential element of learning anatomy in modern times. However it required a significant evolutionary process spread over centuries, for illustrations to achieve the present status in the subject of anatomy. This review article attempts to outline the evolutionary process by highlighting on the works of esteemed anatomists in a chronological manner. Available literature suggests that illustrations were not used in anatomy during the classical period when the subject was dominated by the descriptive text of Galen. Guido da Vigevano was first to use illustrations in anatomy during the Late Middle Ages and this concept developed further during the Renaissance period when Andreas Vesalius pioneered in illustrations becoming an indispensable tool in conveying anatomical details. Toward later stages of the Renaissance period, Fabricius ab Aquapendente endeavored to restrict dramatization of anatomical illustrations which was a prevalent trend in early Renaissance. During the 18th century, anatomical artwork was characterized by the individual styles of prominent anatomists leading to suppression of anatomical details. In the 19th century, Henry Gray used illustrations in his anatomical masterpiece that focused on depicting anatomical structures and were free from any artistic style. From early part of the 20th century medical images and photographs started to complement traditional handmade anatomical illustrations. Computer technology and advanced software systems played a key role in the evolution of anatomical illustrations during the late 20th century resulting in new generation 3D image datasets that are being used in the 21st century in innovative formats for teaching and learning anatomy. PMID:25053471

  6. The first 50 years: A review of the Department of Energy domestic safeguards and security program

    SciTech Connect

    Desmond, W.J.; Zack, N.R.; Tape, J.W.

    1997-12-01

    World War II not only brought the United States rapidly into the nuclear age, but it also brought a new term, {open_quotes}safeguards.{close_quotes} By that time, physical security was an already established activity that dealt with the protection of possessions such as property, vehicles, and other valuables. A secret nuclear project under a stadium at the University of Chicago would add a new dimension to physical security. Similarly, a community known only by its post office box at a location 27 miles from Santa Fe, New Mexico (PO Box 1663) would initiate new programs to protect information and technology while their programs changed the science and warfare around the world. The Manhattan Project and what was to become the Los Alamos Scientific Laboratory (now Los Alamos National Laboratory) would extend the applications of physical security and, soon to be implemented, safeguards to produce important technical advances for the protection, accounting, control, and nonproliferation of fissile nuclear materials. Security for nuclear materials and weapons information began as a foremost consideration with the start of the nuclear programs in the early 1940s. In the 1960s, the Atoms for Peace Program promoted the peaceful use of nuclear energy and made the US a supplier of nuclear materials and peaceful-use nuclear technology to other states. This program also changed the focus on nuclear materials from that of worldwide control to inspection by an independent agency, the proposed International Atomic Energy Agency. At this same time the nuclear weapons states increased from three to five. Other nations worked to obtain a nuclear weapons capability, resulting in increasing concerns about nuclear proliferation.

  7. Periodic coupling strength-dependent multiple coherence resonance by time delay in Newman-Watts neuronal networks.

    PubMed

    Wu, Yanan; Gong, Yubing; Xu, Bo

    2013-12-01

    Recently, multiple coherence resonance induced by time delay has been observed in neuronal networks with constant coupling strength. In this paper, by employing Newman-Watts Hodgkin-Huxley neuron networks with time-periodic coupling strength, we study how the temporal coherence of spiking behavior and coherence resonance by time delay change when the frequency of periodic coupling strength is varied. It is found that delay induced coherence resonance is dependent on periodic coupling strength and increases when the frequency of periodic coupling strength increases. Periodic coupling strength can also induce multiple coherence resonance, and the coherence resonance occurs when the frequency of periodic coupling strength is approximately multiple of the spiking frequency. These results show that for periodic coupling strength time delay can more frequently optimize the temporal coherence of spiking activity, and periodic coupling strength can repetitively optimize the temporal coherence of spiking activity as well. Frequency locking may be the mechanism for multiple coherence resonance induced by periodic coupling strength. These findings imply that periodic coupling strength is more efficient for enhancing the temporal coherence of spiking activity of neuronal networks, and thus it could play a more important role in improving the time precision of information processing and transmission in neural networks. PMID:24060612

  8. Stochastic extinction of tumor cells due to synchronization effect through time periodic treatment in a tumor-immune interaction model

    NASA Astrophysics Data System (ADS)

    Aisu, Ryota; Horita, Takehiko

    The response to a time periodic treatment of the immunotherapy in a stochastic model of tumor-immune interaction is numerically investigated. Due to the effect of synchronization among the intrinsic oscillation and the treatment, an enhanced extinction of the tumor cells is observed. It suggests that compared with the static treatment, by controlling the period of the treatment, the time periodic treatment could be an effective way of treatment leading to tumor extinction.

  9. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  10. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  11. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  12. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  13. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  14. 45 CFR 2526.40 - What is the time period during which an individual may use an education award?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false What is the time period during which an individual may use an education award? 2526.40 Section 2526.40 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE ELIGIBILITY FOR AN EDUCATION AWARD § 2526.40 What is the time period during which...

  15. 41 CFR 302-8.203 - What is the authorized time period for extended storage of my HHG?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... time period for extended storage of my HHG? 302-8.203 Section 302-8.203 Public Contracts and Property Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 8... Continental United States (OCONUS) § 302-8.203 What is the authorized time period for extended storage of...

  16. Sustained and transient attentional processes modulate neural predictors of memory encoding in consecutive time periods

    PubMed Central

    Padovani, Tullia; Koenig, Thomas; Eckstein, Doris; Perrig, Walter J

    2013-01-01

    Memory formation is commonly thought to rely on brain activity following an event. Yet, recent research has shown that even brain activity previous to an event can predict later recollection (subsequent memory effect, SME). In order to investigate the attentional sources of the SME, event-related potentials (ERPs) elicited by task cues preceding target words were recorded in a switched task paradigm that was followed by a surprise recognition test. Stay trials, that is, those with the same task as the previous trial, were contrasted with switch trials, which included a task switch compared to the previous trial. The underlying assumption was that sustained attention would be dominant in stay trials and that transient attentional reconfiguration processes would be dominant in switch trials. To determine the SME, local and global statistics of scalp electric fields were used to identify differences between subsequently remembered and forgotten items. Results showed that the SME in stay trials occurred in a time window from 2 to 1 sec before target onset, whereas the SME in switch trials occurred subsequently, in a time window from 1 to 0 sec before target onset. Both SMEs showed a frontal negativity resembling the topography of previously reported effects, which suggests that sustained and transient attentional processes contribute to the prestimulus SME in consecutive time periods. PMID:24381815

  17. A General Time-Periodic Driving Approach to Realize Topological Phases in Cold Atomic Systems

    PubMed Central

    Yan, Zhongbo; Li, Bo; Yang, Xiaosen; Wan, Shaolong

    2015-01-01

    For time-reversal symmetric cold atomic insulating systems, it is found that the usual driving approach based on electromagnetic field used in solid state systems loses its power to drive them from trivial regimes to topological regimes if the driven systems still hold time-reversal symmetry (TRS). For such systems, we point out that simply varying the optical lattice potential periodically provides a general and effective way to drive them into topological regimes without breaking their symmetries. Based on this approach, we find that the time-reversal symmetric Kane-Mele model can be effectively driven from the trivial phase to topological phases named as Floquet Quantum Spin Hall insulator. Due to the existence of two gaps in the Floquet system, this novel state of matter can stably host one or two pair of gapless helical states on the same boundary, which suggests this state is not a simple analog of the Quantum Spin Hall insulator. This new driving approach to a system without TRS is also investigated. PMID:26541611

  18. Dynamical generalized Hurst exponent as a tool to monitor unstable periods in financial time series

    NASA Astrophysics Data System (ADS)

    Morales, Raffaello; Di Matteo, T.; Gramatica, Ruggero; Aste, Tomaso

    2012-06-01

    We investigate the use of the Hurst exponent, dynamically computed over a weighted moving time-window, to evaluate the level of stability/instability of financial firms. Financial firms bailed-out as a consequence of the 2007-2008 credit crisis show a neat increase with time of the generalized Hurst exponent in the period preceding the unfolding of the crisis. Conversely, firms belonging to other market sectors, which suffered the least throughout the crisis, show opposite behaviors. We find that the multifractality of the bailed-out firms increase at the crisis suggesting that the multi fractal properties of the time series are changing. These findings suggest the possibility of using the scaling behavior as a tool to track the level of stability of a firm. In this paper, we introduce a method to compute the generalized Hurst exponent which assigns larger weights to more recent events with respect to older ones. In this way large fluctuations in the remote past are less likely to influence the recent past. We also investigate the scaling associated with the tails of the log-returns distributions and compare this scaling with the scaling associated with the Hurst exponent, observing that the processes underlying the price dynamics of these firms are truly multi-scaling.

  19. Sustained and transient attentional processes modulate neural predictors of memory encoding in consecutive time periods.

    PubMed

    Padovani, Tullia; Koenig, Thomas; Eckstein, Doris; Perrig, Walter J

    2013-07-01

    Memory formation is commonly thought to rely on brain activity following an event. Yet, recent research has shown that even brain activity previous to an event can predict later recollection (subsequent memory effect, SME). In order to investigate the attentional sources of the SME, event-related potentials (ERPs) elicited by task cues preceding target words were recorded in a switched task paradigm that was followed by a surprise recognition test. Stay trials, that is, those with the same task as the previous trial, were contrasted with switch trials, which included a task switch compared to the previous trial. The underlying assumption was that sustained attention would be dominant in stay trials and that transient attentional reconfiguration processes would be dominant in switch trials. To determine the SME, local and global statistics of scalp electric fields were used to identify differences between subsequently remembered and forgotten items. Results showed that the SME in stay trials occurred in a time window from 2 to 1 sec before target onset, whereas the SME in switch trials occurred subsequently, in a time window from 1 to 0 sec before target onset. Both SMEs showed a frontal negativity resembling the topography of previously reported effects, which suggests that sustained and transient attentional processes contribute to the prestimulus SME in consecutive time periods. PMID:24381815

  20. Multi Band Insar Analysis of Subsidence Development Based on the Long Period Time Series

    NASA Astrophysics Data System (ADS)

    Çomut, F. C.; Ustun, A.; Lazecky, M.; Aref, M. M.

    2015-12-01

    The SAR Interferometry (InSAR) application has shown great potential in monitoring of land terrain changes and in detection of land deformations such as subsidence. Longer time analysis can lead to understand longer trends and changes. Using different bands of SAR satellite (C- from ERS 1-2 and Envisat, L- from ALOS) over the study area, we achieve knowledge of movements in long-term and evaluation of its dynamic changes within observed period of time. Results from InSAR processing fit with the position changes in vertical direction based on GPS network established over the basin as an effective geodetic network. Time series (StaMPS PS+SB) of several points over Çumra County in eastern part of Konya City show a general trend of the deformation that is expected to be approximately between -13 to -17 mm/year. Northern part of Karaman is affected by faster subsidence, borders of the subsidence trough were identified from Envisat. Presenting InSAR results together with GIS information about locations and time of occurrence of sudden subsidence, urban/industrial growth in time and climate changes helps in better understanding of the situation. This way, the impact of natural and man-made changes will be shown for urban planning thanks to InSAR and GIS comparisons with hydrogeological modeling. In this study we present results of differential and multitemporal InSAR series using different bands and GIS conjunction associated with seasonal and temporal groundwater level changes in Konya Closed Basin.

  1. On the periodicity of symbolic observations of piecewise smooth discrete-time systems

    NASA Technical Reports Server (NTRS)

    Ramadge, Peter J.

    1990-01-01

    A study is made of the behavior of discrete-time systems composed of a set of smooth transition maps coupled by a quantized feedback function. The feedback function partitions the state space into disjoint regions and assigns a smooth transition function to each region. The main result is that under a constraint on the norm of the derivative of the transition maps, a bounded state trajectory with limit points in the interior of the switching regions leads to a region index sequence that is eventually periodic. Under these assumptions, it is shown that eventually the feedback function is determined by a finite state automaton. A similar result is proved in the case of finite state dynamic feedback.

  2. Removing tidal-period variations from time-series data using low-pass digital filters

    USGS Publications Warehouse

    Walters, Roy A.; Heston, Cynthia

    1982-01-01

    Several low-pass, digital filters are examined for their ability to remove tidal Period Variations from a time-series of water surface elevation for San Francisco Bay. The most efficient filter is the one which is applied to the Fourier coefficients of the transformed data, and the filtered data recovered through an inverse transform. The ability of the filters to remove the tidal components increased in the following order: 1) cosine-Lanczos filter, 2) cosine-Lanczos squared filter; 3) Godin filter; and 4) a transform fitter. The Godin fitter is not sufficiently sharp to prevent severe attenuation of 2–3 day variations in surface elevation resulting from weather events.

  3. Controllability discrepancy and irreducibility/reducibility of Floquet factorisations in linear continuous-time periodic systems

    NASA Astrophysics Data System (ADS)

    Zhou, Jun; Lu, Xinbiao; Qian, Huimin

    2016-09-01

    The paper reports interesting but unnoticed facts about irreducibility (resp., reducibility) of Flouqet factorisations and their harmonic implication in term of controllability in finite-dimensional linear continuous-time periodic (FDLCP) systems. Reducibility and irreducibility are attributed to matrix logarithm algorithms during computing Floquet factorisations in FDLCP systems, which are a pair of essential features but remain unnoticed in the Floquet theory so far. The study reveals that reducible Floquet factorisations may bring in harmonic waves variance into the Fourier analysis of FDLCP systems that in turn may alter our interpretation of controllability when the Floquet factors are used separately during controllability testing; namely, controllability interpretation discrepancy (or simply, controllability discrepancy) may occur and must be examined whenever reducible Floquet factorisations are involved. On the contrary, when irreducible Floquet factorisations are employed, controllability interpretation discrepancy can be avoided. Examples are included to illustrate such observations.

  4. Intercomparison of UT1 measurements during the MERIT campaign period. [Universal Time

    NASA Technical Reports Server (NTRS)

    Spieth, M. A.; Eubanks, T. M.; Steppe, J. A.

    1986-01-01

    Universal time (UT1) measurements obtained using VLBI, lunar laser ranging (LLR), and BIH optical astronomy are compared. The JPL Kalman filter for the earth rotation and the polar motion is utilized to smooth one data set or combine data sets for intercomparison. The differences between raw UT1 data and independently smoothed data are employed to assess the accuracy of the measured series and the sufficiency of the error budget. Systematic errors in periodic signatures and length of day estimates are analyzed. The data reveal that the techniques of LLR and VLBI agree to within their formal errors. It is determined that the residual error for the LLR is too large and the residual error estimated for the BIH data is too small.

  5. Efficiency, Power and Period of a model quantum heat engine working in a finite time

    NASA Astrophysics Data System (ADS)

    Bekele, Mulugeta; Dima, Tolasa A.; Alemye, Mekuannent; Chegeno, Warga

    We take a spin-half quantum particle undergoing Carnot type cyclic process in a finite time assisted by two heat reservoirs and an external magnetic field. We find that the power of the heat engine is maximum at a particular period of the cyclic process and efficiency at the maximum power is at least half of the Carnot efficiency. We further apply the Omega-criterion for a figure of merit representing a compromise between useful power and lost power determining the corresponding efficiency for the optimization criterion to be at least three fourth of the Carnot efficiency. The authers are thankful to the International Science programme, IPS, Uppsala, Sweden for their support to our research lab.

  6. Network news coverage of obesity in two time periods: an analysis of issues, sources, and frames.

    PubMed

    Gearhart, Sherice; Craig, Clay; Steed, Chaille

    2012-01-01

    Obesity is an epidemic plaguing American society. The current study adds to a growing body of framing research as it examines the portrayal of obesity on television network news in two 5-year time periods, 1995-1999 and 2005-2009. Through content analysis of TV news transcripts from three networks (ABC, NBC, and CBS), this study analyzed episodic-thematic frames, issues, and sources. Results revealed the amount of obesity-related news coverage increased along with thematically framed stories. The use of politicians, affected others, supporters, and others as sources increased, but experts and those struggling with obesity remained primary sources. Changes in the proportion of issues discussed revealed significant decreases in the discussion of genetic causes and personal stories. Results reflect the societal impact of obesity and indicate the ways in which obesity is perceived by the public through network news. Findings provide insight for media advocacy opportunities and contribute to research on framing and obesity. PMID:22236324

  7. 50 years of mass spectrometry at Firmenich: a continuing love story.

    PubMed

    Frérot, Eric; Wünsche, Laurent

    2014-01-01

    Mass spectrometry (MS) has been intensively used in the field of flavor and fragrance since its beginning in the 1950s, and it remains an essential technique for current and future research in this field. After a short historical section on the introduction and development of MS at Firmenich, this work reviews the main applications of MS-based techniques published by Firmenich researchers over the past 5 years. It exemplifies the use of gas chromatography (GC)-MS for the discovery of new odorant - hence volatile - molecules in a broad range of natural products, such as fruits, meats, and vegetables. Non-volatile compounds play a major role in taste attributes and are also possible precursors of odorant molecules. Their identification by liquid chromatography (LC)-MS in the context of malodor generation from sweat is a typical example of such a relationship. With their high selectivity and sensitivity, GC-MS and LC-MS instruments are used in the fields of flavor and fragrance not only for identification, but also as unique tools for the accurate quantitation of compounds in complex matrices. This is particularly important for regulatory analyses such as dosage of potential allergens in perfumes and for the development of delivery systems. Finally, because of the rapid response time of MS, the kinetics of processes such as the release of flavors in the mouth during food consumption can be monitored by direct sampling into the mass spectrometer. PMID:24801848

  8. [Gregorio Marañón, a pioneer of endocrinology, 50 years after his death].

    PubMed

    Zarate, Arturo

    2011-01-01

    Gregorio Maranon born and dead in Madrid (1887-1960), was a Spanish physician, scientist, historian, philosopher, humanist, and writer, considered one of the most brilliant Spanish intellectuals of the 20th century. He was also a Republican and fought the Primo de Rivera dictatorship, though later expressed his disagreement with communism. Maranon participated closely with the process of exile of Alfonso XIII. From a very early age he learned several foreign languages and was an avid reader, hence he became in contact with the intellectual circles of the time and cultivated a close friendship with Perez Galdos, Menendez-Pelayo, Ortega y Gasset, Pio Baroja, Unamuno, Lerroux among several outstanding and eminent figures of the famous Generation of 14. In Medical School he had great teachers such as Santiago Ramon y Cajal, and later he specialized in endocrinology and became professor of the specialty in the Complutense University in Madrid, moreover he founded the Institute of Medical Pathology and the Department of Experimental Endocrinology, henceforth he contributed to establish the relationship between endocrinology and psychology. At the beginning of the instauration of the Republic, Maranon became a member of the constituent assembly and the parliament, but soon became disillusioned of communism and left Spain before the initiation of the Civil War, remaining in France until 1942 when he returned to Spain to reestablish his private practice, and soon the medical teaching at the hospital which now bears his name. Late work about history, poetry was elaborated at his Toledo Cigarral de Menores. PMID:21527976

  9. Evolution of stickleback in 50 years on earthquake-uplifted islands.

    PubMed

    Lescak, Emily A; Bassham, Susan L; Catchen, Julian; Gelmond, Ofer; Sherbick, Mary L; von Hippel, Frank A; Cresko, William A

    2015-12-29

    How rapidly can animal populations in the wild evolve when faced with sudden environmental shifts? Uplift during the 1964 Great Alaska Earthquake abruptly created freshwater ponds on multiple islands in Prince William Sound and the Gulf of Alaska. In the short time since the earthquake, the phenotypes of resident freshwater threespine stickleback fish on at least three of these islands have changed dramatically from their oceanic ancestors. To test the hypothesis that these freshwater populations were derived from oceanic ancestors only 50 y ago, we generated over 130,000 single-nucleotide polymorphism genotypes from more than 1,000 individuals using restriction site-associated DNA sequencing (RAD-seq). Population genomic analyses of these data support the hypothesis of recent and repeated, independent colonization of freshwater habitats by oceanic ancestors. We find evidence of recurrent gene flow between oceanic and freshwater ecotypes where they co-occur. Our data implicate natural selection in phenotypic diversification and support the hypothesis that the metapopulation organization of this species helps maintain a large pool of genetic variation that can be redeployed rapidly when oceanic stickleback colonize freshwater environments. We find that the freshwater populations, despite population genetic analyses clearly supporting their young age, have diverged phenotypically from oceanic ancestors to nearly the same extent as populations that were likely founded thousands of years ago. Our results support the intriguing hypothesis that most stickleback evolution in fresh water occurs within the first few decades after invasion of a novel environment. PMID:26668399

  10. Evolution of stickleback in 50 years on earthquake-uplifted islands

    PubMed Central

    Lescak, Emily A.; Bassham, Susan L.; Catchen, Julian; Gelmond, Ofer; Sherbick, Mary L.; von Hippel, Frank A.

    2015-01-01

    How rapidly can animal populations in the wild evolve when faced with sudden environmental shifts? Uplift during the 1964 Great Alaska Earthquake abruptly created freshwater ponds on multiple islands in Prince William Sound and the Gulf of Alaska. In the short time since the earthquake, the phenotypes of resident freshwater threespine stickleback fish on at least three of these islands have changed dramatically from their oceanic ancestors. To test the hypothesis that these freshwater populations were derived from oceanic ancestors only 50 y ago, we generated over 130,000 single-nucleotide polymorphism genotypes from more than 1,000 individuals using restriction site-associated DNA sequencing (RAD-seq). Population genomic analyses of these data support the hypothesis of recent and repeated, independent colonization of freshwater habitats by oceanic ancestors. We find evidence of recurrent gene flow between oceanic and freshwater ecotypes where they co-occur. Our data implicate natural selection in phenotypic diversification and support the hypothesis that the metapopulation organization of this species helps maintain a large pool of genetic variation that can be redeployed rapidly when oceanic stickleback colonize freshwater environments. We find that the freshwater populations, despite population genetic analyses clearly supporting their young age, have diverged phenotypically from oceanic ancestors to nearly the same extent as populations that were likely founded thousands of years ago. Our results support the intriguing hypothesis that most stickleback evolution in fresh water occurs within the first few decades after invasion of a novel environment. PMID:26668399

  11. Low-thrust roundtrip trajectories to Mars with one-synodic-period repeat time

    NASA Astrophysics Data System (ADS)

    Okutsu, Masataka; Landau, Damon F.; Rogers, Blake A.; Longuski, James M.

    2015-05-01

    Cycler trajectories-both ballistic and powered-are reported in the literature in which there are two-vehicle, three-vehicle, and four-vehicle cases. Such trajectories permit the installation of cycler vehicles which provide safe and comfortable living conditions for human space travel between Earth and Mars during every synodic opportunity. The question the present paper answers is a logical, obvious one: Does a single-vehicle, one-synodic-period cycler exist? The answer is yes: such a trajectory can be flown-but only with a high-power electric propulsion system. In our example, it is found that "stopover" trajectories that spend 30 days in orbit about Earth and 30 days about Mars, and return astronauts to Earth in one synodic period require a 90-t power generator with a power level of 11 MWe. Fortuitously, and in lieu of using chemical propulsion, the high power level of the electric propulsion system would also be effective in hauling the cargo payload via a spiral trajectory about the Earth. But because one synodic period is not enough for the cycler vehicle to fly both the interplanetary trajectories and the Earth-spiral trajectories, we suggest developing two nuclear power generators, which could alternate flying the interplanetary trajectories and the Earth-spiral trajectories. Once these power generators are launched and begin operating in space, the mass requirement in seven subsequent missions (over a period of 15 years beginning in 2022) would be modest at 250-300 metric tons to low-Earth orbit per mission. Thus two cargo launches of NASA's Space Launch System and one crew launch of the Falcon Heavy, for example, would be adequate to maintain support for each consecutive mission. Although we propose developing two sets of electric propulsion systems to account for the Earth-spiral phases, only one vehicle is flown on a heliocentric trajectory at any given time. Thus, our low-thrust stopover cycler with zero encounter velocities falls into a category of a

  12. Spectral analysis of radial Dirac operators in the Kerr-Newman metric and its applications to time-periodic solutions

    NASA Astrophysics Data System (ADS)

    Winklmeier, Monika; Yamada, Osanobu

    2006-10-01

    We investigate the existence of time-periodic solutions of the Dirac equation in the Kerr-Newman background metric. To this end, the solutions are expanded in a Fourier series with respect to the time variable t, and the Chandrasekhar separation ansatz is applied so that the question of existence of a time-periodic solution is reduced to the solvability of a certain coupled system of ordinary differential equations. First, we prove the already known result that there are no time-periodic solutions in the nonextreme case. Then, it is shown that in the extreme case for fixed black hole data there is a sequence of particle masses (mN)NɛN for which a time-periodic solution of the Dirac equation does exist. The period of the solution depends only on the data of the black hole described by the Kerr-Newman metric.

  13. Govindjee at 80: more than 50 years of free energy for photosynthesis.

    PubMed

    Eaton-Rye, Julian J

    2013-10-01

    We provide here a glimpse of Govindjee and his pioneering contributions on the two light reactions and the two pigment systems, particularly on the water-plastoquinone oxido-reductase, Photosystem II. His focus has been on excitation energy transfer; primary photochemistry, and the role of bicarbonate in electron and proton transfer. His major tools have been kinetics and spectroscopy (absorption and fluorescence), and he has provided an understanding of both thermoluminescence and delayed light emission in plants and algae. He pioneered the use of lifetime of fluorescence measurements to study the phenomenon of photoprotection in plants and algae. He, however, is both a generalist and a specialist all at the same time. He communicates very effectively his passion for photosynthesis to the novice as well as professionals. He has been a prolific author, outstanding lecturer and an editor par excellence. He is the founder not only of the Historical Corner of Photosynthesis Research, but of the highly valued Series Advances in Photosynthesis and Respiration Including Bioenergy and Related Processes. He reaches out to young people by distributing Z-scheme posters, presenting Awards of books, and through tri-annual articles on "Photosynthesis Web Resources". At home, at the University of Illinois at Urbana-Champaign, he has established student Awards for Excellence in Biological Sciences. On behalf of all his former graduate students and associates, I wish him a Happy 80th birthday. I have included here several tributes to Govindjee by his well-wishers. These write-ups express the high regard the photosynthesis community holds for "Gov" and illuminate the different facets of his life and associations. PMID:24113923

  14. Plutonium: The first 50 years. United States plutonium production, acquisition, and utilization from 1944 through 1994

    SciTech Connect

    1996-02-01

    The report contains important newly declassified information regarding the US production, acquisition, and removals of plutonium. This new information, when combined with previously declassified data, has allowed the DOE to issue, for the first time, a truly comprehensive report on the total DOE plutonium inventory. At the December 7, 1993, Openness Press Conference, the DOE declassified the plutonium inventories at eight locations totaling 33.5 metric tons (MT). This report declassifies the remainder of the DOE plutonium inventory. Newly declassified in this report is the quantity of plutonium at the Pantex Site, near Amarillo, Texas, and in the US nuclear weapons stockpile of 66.1 MT, which, when added to the previously released inventory of 33.5 MT, yields a total plutonium inventory of 99.5 MT. This report will document the sources which built up the plutonium inventory as well as the transactions which have removed plutonium from that inventory. This report identifies four sources that add plutonium to the DOE/DoD inventory, and seven types of transactions which remove plutonium from the DOE/DoD inventory. This report also discusses the nuclear material control and accountability system which records all nuclear material transactions, compares records with inventory and calculates material balances, and analyzes differences to verify that nuclear materials are in quantities as reported. The DOE believes that this report will aid in discussions in plutonium storage, safety, and security with stakeholders as well as encourage other nations to declassify and release similar data. These data will also be available for formulating policies with respect to disposition of excess nuclear materials. The information in this report is based on the evaluation of available records. The information contained in this report may be updated or revised in the future should additional or more detailed data become available.

  15. The Living Filter: Monitoring Nitrate Accumulation after 50 Years of Wastewater Irrigation

    NASA Astrophysics Data System (ADS)

    Hagedorn, J.

    2015-12-01

    As global freshwater sources decline due to environmental contamination and a growing population, more sustainable wastewater renovation techniques will need to be applied to ensure freshwater for future generations. One such example of a sustainable solution is called the Living Filter, located on the campus of Pennsylvania State University. For fifty years, Pennsylvania State University has sprayed treated wastewater onto agricultural fields and forest ecosystems, leaving natural processes to further filter the wastewater. This cyclical process is deemed sustainable because the freshwater is recycled, providing drinking water to an increasing university population and nutrients to agricultural crops, without causing major environmental catastrophes such as fish kills, eutrophication or groundwater contamination. At first glance this project seems sustainable and effective, but for how long can this setup continue without nutrient overloading and environmental contamination? To be truly declared sustainable, the hopeful answer to this question is indefinitely. Using a combination of soil core and monitoring tools, ecosystem indicators such as soil nutrient capacities, moisture levels, and soil characteristics were measured. Comparing data from the initial system installation to present data collected from soil cores showed how ecosystems changed over time. Results revealed that nitrate concentrations were elevated through the profile in all land use types, but the concentrations were below EPA threshold. Soil characteristic analysis including particle size distribution, soil elemental composition, and texture yielded inconclusive results regarding which factors control the nitrate accumulation most significantly. The nitrate depth profile findings suggest that spray irrigation at the Living Filter under the current rates of application has not caused the ultimate stage of nitrogen saturation in the spray irrigation site. Variations in land use present interesting

  16. Atoms for Peace After 50 Years: The New Challenges and Opportunities

    DOE R&D Accomplishments Database

    2003-12-01

    This report draws on a series of international workshops held to mark the fiftieth anniversary of President Dwight D. Eisenhower's Atoms for Peace address before the United Nations General Assembly. A half-century after President Eisenhower's landmark speech, the world is vastly different, but mankind still faces the challenge he identified--gaining the benefits of nuclear technology in a way that limits the risks to security. Fifty years after Eisenhower declared that the people of the world should be "armed with the significant facts of today's existence," the consequences of his bold vision should be evaluated to provide a foundation upon which to shape the next fifty years. Policy and technology communities cannot escape the legacy of a half-century of nuclear technology expansion. At the same time, citizens need to consider the future role of military and civilian nuclear technology in a global strategy to meet the challenges of the twenty-first century. The new century brought with it a set of contradictions regarding nuclear technology. Nuclear knowledge, technology, materials, and facilities have spread around the world, but control and management of the nuclear genie have not kept pace. The Cold War is over, but not the threat from weapons of mass destruction, including the prospect that nuclear, chemical, or biological weapons may get into the hands of terrorists. Nevertheless, mankind continues to explore the frontiers of technology, including nuclear technology. Public concern about nuclear safety and security--exacerbated by accidents, nuclear weapon proliferation, and terrorism--confronts major growth in applications of nuclear technology in nuclear power, medicine, agriculture, and industry. While some developed countries have essentially stopped civilian nuclear-power expansion, mainly for economic reasons, several developing states--notably China and India--plan increases in the nuclear generation of electricity. Ironically, while governments still

  17. Atoms for Peace After 50 Years: The New Challenges and Opportunities

    SciTech Connect

    Schock, R N

    2003-11-12

    This report draws on a series of international workshops held to mark the fiftieth anniversary of President Dwight D. Eisenhower's Atoms for Peace address before the United Nations General Assembly. A half-century after President Eisenhower's landmark speech, the world is vastly different, but mankind still faces the challenge he identified--gaining the benefits of nuclear technology in a way that limits the risks to security. Fifty years after Eisenhower declared that the people of the world should be ''armed with the significant facts of today's existence,'' the consequences of his bold vision should be evaluated to provide a foundation upon which to shape the next fifty years. Policy and technology communities cannot escape the legacy of a half-century of nuclear technology expansion. At the same time, citizens need to consider the future role of military and civilian nuclear technology in a global strategy to meet the challenges of the twenty-first century. The new century brought with it a set of contradictions regarding nuclear technology. Nuclear knowledge, technology, materials, and facilities have spread around the world, but control and management of the nuclear genie have not kept pace. The Cold War is over, but not the threat from weapons of mass destruction, including the prospect that nuclear, chemical, or biological weapons may get into the hands of terrorists. Nevertheless, mankind continues to explore the frontiers of technology, including nuclear technology. Public concern about nuclear safety and security--exacerbated by accidents, nuclear weapon proliferation, and terrorism--confronts major growth in applications of nuclear technology in nuclear power, medicine, agriculture, and industry. While some developed countries have essentially stopped civilian nuclear-power expansion, mainly for economic reasons, several developing states--notably China and India--plan increases in the nuclear generation of electricity. Ironically, while governments

  18. Time periods of GSR particles deposition after discharge-final results.

    PubMed

    Fojtásek, Lubor; Kmjec, Tomás

    2005-10-29

    The elemental objects of the research study are: determination of time periods corresponding to gunshot residue particles (GSR) deposition after the shot from selected pistols and a revolver, and evaluation of the deposited particles number. For several shooting experiments were used a pistol CZ model 85, caliber 9 mm Luger with common ammunition 9 mm Luger FMJ Sellier & Bellot, a pistol CZ model 70, caliber 7.65 mm Browning (32 ACP) with common 7.65 mm Browning FMJ Sellier & Bellot ammunition and a revolver S&W Modell 60, barell length 2-1/8'', cal. .38 Special with common Sellier&Bellot (FMJ) ammunition. The results of the study have indicated the behavior of GSR particles deposited after a single discharge. The overall time interval of GSR particles deposition and the number of deposited particles with the above mentioned arms and ammunition were established. The results can potentially be used for clarifying the situation at crime scenes and for subsequent interpretation of GSR evidential value in caseworks. PMID:16139100

  19. The timing of vortex shedding in a cylinder wake imposed by periodic inflow perturbations

    NASA Astrophysics Data System (ADS)

    Konstantinidis, E.; Balabani, S.; Yianneskis, M.

    2005-10-01

    The interaction of vortex shedding from a circular cylinder with an inflow which has low-amplitude periodic velocity oscillations (perturbations) superimposed upon it, was investigated experimentally by means of particle image velocimetry. The experiments were made at three perturbation frequencies across the lock-on range in which the vortex shedding frequency is synchronized with the subharmonic of the imposed frequency. The basic wake pattern in this range is antisymmetric vortex shedding, i.e. the familiar 2S mode. The timing of vortex shedding is defined with respect to the cross-flow oscillation of the wake which is found to play a critical role. Quantitative analysis of the phase-referenced patterns of vorticity distribution in the wake shows that a vortex is actually shed from the cylinder when the cross-flow oscillation of the wake is strongest, marked by a sudden drop in the computed vortex strength. At the middle of the lock-on range, shedding occurs near the minimum inflow velocity in the cycle or, equivalently, during the forward stroke of a cylinder oscillating in-line with the flow. It is argued that the imposed timing of vortex shedding relative to the cylinder motion induces a negative excitation from the fluid, which might explain why the in-line response of a freely vibrating cylinder exhibits two positive excitation regions separated by the lock-on region found in forced oscillations.

  20. Estimating interevent time distributions from finite observation periods in communication networks

    NASA Astrophysics Data System (ADS)

    Kivelä, Mikko; Porter, Mason A.

    2015-11-01

    A diverse variety of processes—including recurrent disease episodes, neuron firing, and communication patterns among humans—can be described using interevent time (IET) distributions. Many such processes are ongoing, although event sequences are only available during a finite observation window. Because the observation time window is more likely to begin or end during long IETs than during short ones, the analysis of such data is susceptible to a bias induced by the finite observation period. In this paper, we illustrate how this length bias is born and how it can be corrected without assuming any particular shape for the IET distribution. To do this, we model event sequences using stationary renewal processes, and we formulate simple heuristics for determining the severity of the bias. To illustrate our results, we focus on the example of empirical communication networks, which are temporal networks that are constructed from communication events. The IET distributions of such systems guide efforts to build models of human behavior, and the variance of IETs is very important for estimating the spreading rate of information in networks of temporal interactions. We analyze several well-known data sets from the literature, and we find that the resulting bias can lead to systematic underestimates of the variance in the IET distributions and that correcting for the bias can lead to qualitatively different results for the tails of the IET distributions.