Using GRACE Satellite Gravimetry for Assessing Large-Scale Hydrologic Extremes

Directory of Open Access Journals (Sweden)

Alexander Y. Sun

2017-12-01

Full Text Available Global assessment of the spatiotemporal variability in terrestrial total water storage anomalies (TWSA in response to hydrologic extremes is critical for water resources management. Using TWSA derived from the gravity recovery and climate experiment (GRACE satellites, this study systematically assessed the skill of the TWSA-climatology (TC approach and breakpoint (BP detection method for identifying large-scale hydrologic extremes. The TC approach calculates standardized anomalies by using the mean and standard deviation of the GRACE TWSA corresponding to each month. In the BP detection method, the empirical mode decomposition (EMD is first applied to identify the mean return period of TWSA extremes, and then a statistical procedure is used to identify the actual occurrence times of abrupt changes (i.e., BPs in TWSA. Both detection methods were demonstrated on basin-averaged TWSA time series for the world’s 35 largest river basins. A nonlinear event coincidence analysis measure was applied to cross-examine abrupt changes detected by these methods with those detected by the Standardized Precipitation Index (SPI. Results show that our EMD-assisted BP procedure is a promising tool for identifying hydrologic extremes using GRACE TWSA data. Abrupt changes detected by the BP method coincide well with those of the SPI anomalies and with documented hydrologic extreme events. Event timings obtained by the TC method were ambiguous for a number of river basins studied, probably because the GRACE data length is too short to derive long-term climatology at this time. The BP approach demonstrates a robust wet-dry anomaly detection capability, which will be important for applications with the upcoming GRACE Follow-On mission.

Report from the 2nd Workshop on Extremely Large Databases

Directory of Open Access Journals (Sweden)

Jacek Becla

2009-03-01

Full Text Available The complexity and sophistication of large scale analytics in science and industry have advanced dramatically in recent years. Analysts are struggling to use complex techniques such as time series analysis and classification algorithms because their familiar, powerful tools are not scalable and cannot effectively use scalable database systems. The 2nd Extremely Large Databases (XLDB workshop was organized to understand these issues, examine their implications, and brainstorm possible solutions. The design of a new open source science database, SciDB that emerged from the first workshop in this series was also debated. This paper is the final report of the discussions and activities at this workshop.

Large-Scale Atmospheric Circulation Patterns Associated with Temperature Extremes as a Basis for Model Evaluation: Methodological Overview and Results

Science.gov (United States)

Loikith, P. C.; Broccoli, A. J.; Waliser, D. E.; Lintner, B. R.; Neelin, J. D.

2015-12-01

Anomalous large-scale circulation patterns often play a key role in the occurrence of temperature extremes. For example, large-scale circulation can drive horizontal temperature advection or influence local processes that lead to extreme temperatures, such as by inhibiting moderating sea breezes, promoting downslope adiabatic warming, and affecting the development of cloud cover. Additionally, large-scale circulation can influence the shape of temperature distribution tails, with important implications for the magnitude of future changes in extremes. As a result of the prominent role these patterns play in the occurrence and character of extremes, the way in which temperature extremes change in the future will be highly influenced by if and how these patterns change. It is therefore critical to identify and understand the key patterns associated with extremes at local to regional scales in the current climate and to use this foundation as a target for climate model validation. This presentation provides an overview of recent and ongoing work aimed at developing and applying novel approaches to identifying and describing the large-scale circulation patterns associated with temperature extremes in observations and using this foundation to evaluate state-of-the-art global and regional climate models. Emphasis is given to anomalies in sea level pressure and 500 hPa geopotential height over North America using several methods to identify circulation patterns, including self-organizing maps and composite analysis. Overall, evaluation results suggest that models are able to reproduce observed patterns associated with temperature extremes with reasonable fidelity in many cases. Model skill is often highest when and where synoptic-scale processes are the dominant mechanisms for extremes, and lower where sub-grid scale processes (such as those related to topography) are important. Where model skill in reproducing these patterns is high, it can be inferred that extremes are

Report from the 6th Workshop on Extremely Large Databases

Directory of Open Access Journals (Sweden)

Daniel Liwei Wang

2013-05-01

Full Text Available Petascale data management and analysis remain one of the main unresolved challenges in today's computing. The 6th Extremely Large Databases workshop was convened alongside the XLDB conference to discuss the challenges in the health care, biology, and natural resources communities. The role of cloud computing, the dominance of file-based solutions in science applications, in-situ and predictive analysis, and commercial software use in academic environments were discussed in depth as well. This paper summarizes the discussions of this workshop.

Extreme temperatures and out-of-hospital coronary deaths in six large Chinese cities.

Science.gov (United States)

Chen, Renjie; Li, Tiantian; Cai, Jing; Yan, Meilin; Zhao, Zhuohui; Kan, Haidong

2014-12-01

The seasonal trend of out-of-hospital coronary death (OHCD) and sudden cardiac death has been observed, but whether extreme temperature serves as a risk factor is rarely investigated. We therefore aimed to evaluate the impact of extreme temperatures on OHCDs in China. We obtained death records of 126,925 OHCDs from six large Chinese cities (Harbin, Beijing, Tianjin, Nanjing, Shanghai and Guangzhou) during the period 2009-2011. The short-term associations between extreme temperature and OHCDs were analysed with time-series methods in each city, using generalised additive Poisson regression models. We specified distributed lag non-linear models in studying the delayed effects of extreme temperature. We then applied Bayesian hierarchical models to combine the city-specific effect estimates. The associations between extreme temperature and OHCDs were almost U-shaped or J-shaped. The pooled relative risks (RRs) of extreme cold temperatures over the lags 0-14 days comparing the 1st and 25th centile temperatures were 1.49 (95% posterior interval (PI) 1.26-1.76); the pooled RRs of extreme hot temperatures comparing the 99th and 75th centile temperatures were 1.53 (95% PI 1.27-1.84) for OHCDs. The RRs of extreme temperature on OHCD were higher if the patients with coronary heart disease were old, male and less educated. This multicity epidemiological study suggested that both extreme cold and hot temperatures posed significant risks on OHCDs, and might have important public health implications for the prevention of OHCD or sudden cardiac death. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Extremely large breast abscess in a breastfeeding mother.

Science.gov (United States)

Martic, Krešimir; Vasilj, Oliver

2012-11-01

Puerperal mastitis often occurs in younger primiparous women. Most cases occur between 3 and 8 weeks postpartum. If mastitis results in the formation of a breast abscess, surgical drainage or needle aspiration is most commonly performed. We report a case of an extremely large breast abscess in a primiparous 20-year-old woman, which presented 6 weeks postpartum. Surgical incision and evacuation of 2 liters of exudate were performed, and intravenous antibiotics therapy was administered. On the sixth day after incision, we secondarily closed the wound. Examination after 3 months showed symmetrical breasts with a small scar in the incision area of the right breast. A high degree of suspicion and adequate diagnostic procedures are essential to avoid delay in the treatment of mastitis and breast abscess and thereby prevent unnecessary surgical treatment.

Extreme value statistics and thermodynamics of earthquakes. Large earthquakes

Energy Technology Data Exchange (ETDEWEB)

Lavenda, B. [Camerino Univ., Camerino, MC (Italy); Cipollone, E. [ENEA, Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy). National Centre for Research on Thermodynamics

2000-06-01

A compound Poisson process is used to derive a new shape parameter which can be used to discriminate between large earthquakes and aftershocks sequences. Sample exceedance distributions of large earthquakes are fitted to the Pareto tail and the actual distribution of the maximum to the Frechet distribution, while the sample distribution of aftershocks are fitted to a Beta distribution and the distribution of the minimum to the Weibull distribution for the smallest value. The transition between initial sample distributions and asymptotic extreme value distributions show that self-similar power laws are transformed into non scaling exponential distributions so that neither self-similarity nor the Gutenberg-Richter law can be considered universal. The energy-magnitude transformation converts the Frechet distribution into the Gumbel distribution, originally proposed by Epstein and Lomnitz, and not the Gompertz distribution as in the Lomnitz-Adler and Lomnitz generalization of the Gutenberg-Richter law. Numerical comparison is made with the Lomnitz-Adler and Lomnitz analysis using the same catalogue of Chinese earthquakes. An analogy is drawn between large earthquakes and high energy particle physics. A generalized equation of state is used to transform the Gamma density into the order-statistic Frechet distribution. Earthquake temperature and volume are determined as functions of the energy. Large insurance claims based on the Pareto distribution, which does not have a right endpoint, show why there cannot be a maximum earthquake energy.

Extreme value statistics and thermodynamics of earthquakes: large earthquakes

Directory of Open Access Journals (Sweden)

B. H. Lavenda

2000-06-01

Full Text Available A compound Poisson process is used to derive a new shape parameter which can be used to discriminate between large earthquakes and aftershock sequences. Sample exceedance distributions of large earthquakes are fitted to the Pareto tail and the actual distribution of the maximum to the Fréchet distribution, while the sample distribution of aftershocks are fitted to a Beta distribution and the distribution of the minimum to the Weibull distribution for the smallest value. The transition between initial sample distributions and asymptotic extreme value distributions shows that self-similar power laws are transformed into nonscaling exponential distributions so that neither self-similarity nor the Gutenberg-Richter law can be considered universal. The energy-magnitude transformation converts the Fréchet distribution into the Gumbel distribution, originally proposed by Epstein and Lomnitz, and not the Gompertz distribution as in the Lomnitz-Adler and Lomnitz generalization of the Gutenberg-Richter law. Numerical comparison is made with the Lomnitz-Adler and Lomnitz analysis using the same Catalogue of Chinese Earthquakes. An analogy is drawn between large earthquakes and high energy particle physics. A generalized equation of state is used to transform the Gamma density into the order-statistic Fréchet distribution. Earthquaketemperature and volume are determined as functions of the energy. Large insurance claims based on the Pareto distribution, which does not have a right endpoint, show why there cannot be a maximum earthquake energy.

[Parallel virtual reality visualization of extreme large medical datasets].

Science.gov (United States)

Tang, Min

2010-04-01

On the basis of a brief description of grid computing, the essence and critical techniques of parallel visualization of extreme large medical datasets are discussed in connection with Intranet and common-configuration computers of hospitals. In this paper are introduced several kernel techniques, including the hardware structure, software framework, load balance and virtual reality visualization. The Maximum Intensity Projection algorithm is realized in parallel using common PC cluster. In virtual reality world, three-dimensional models can be rotated, zoomed, translated and cut interactively and conveniently through the control panel built on virtual reality modeling language (VRML). Experimental results demonstrate that this method provides promising and real-time results for playing the role in of a good assistant in making clinical diagnosis.

Electric-field-induced extremely large change in resistance in graphene ferromagnets

Science.gov (United States)

Song, Yu

2018-01-01

A colossal magnetoresistance (˜100×10^3% ) and an extremely large magnetoresistance (˜1×10^6% ) have been previously explored in manganite perovskites and Dirac materials, respectively. However, the requirement of an extremely strong magnetic field (and an extremely low temperature) makes them not applicable for realistic devices. In this work, we propose a device that can generate even larger changes in resistance in a zero-magnetic field and at a high temperature. The device is composed of graphene under two strips of yttrium iron garnet (YIG), where two gate voltages are applied to cancel the heavy charge doping in the YIG-induced half-metallic ferromagnets. By calculations using the Landauer-Büttiker formalism, we demonstrate that, when a proper gate voltage is applied on the free ferromagnet, changes in resistance up to 305×10^6% (16×10^3% ) can be achieved at the liquid helium (nitrogen) temperature and in a zero magnetic field. We attribute such a remarkable effect to a gate-induced full-polarization reversal in the free ferromagnet, which results in a metal-state to insulator-state transition in the device. We also find that the proposed effect can be realized in devices using other magnetic insulators, such as EuO and EuS. Our work should be helpful for developing a realistic switching device that is energy saving and CMOS-technology compatible.

Large Extremity Peripheral Nerve Repair

Science.gov (United States)

2016-12-01

LM, de Crombrugghe B. Some recent advances in the chemistry and biology of trans- forming growth factor-beta. J Cell Biol 1987;105:1039e45. 12. Hao Y...SUPPLEMENTARY NOTES 14. ABSTRACT In current war trauma, 20-30% of all extremity injuries and >80% of penetrating injuries being associated with peripheral nerve...through both axonal advance and in revascularization of the graft following placement. We are confident that this technology may allow us to

The potential of the ILC for discovering new particles

Energy Technology Data Exchange (ETDEWEB)

Fujii, Keisuke [High Energy Accelerator Research Organization (KEK), Ibaraki (Japan); Grojean, Christophe [DESY, Hamburg (Germany); Humboldt-Univ., Berlin (Germany). Inst. fuer Physik; ICREA, Barcelona (Spain); Peskin, Michael E. [Stanford Univ., Menlo Park, CA (United States). SLAC; Collaboration: LCC Physics Working Group; and others

2017-02-15

This paper addresses the question of whether the International Linear Collider has the capability of discovering new particles that have not already been discovered at the CERN Large Hadron Collider. We summarize the various paths to discovery offered by the ILC, and discuss them in the context of three different scenarios: 1. LHC does not discover any new particles, 2. LHC discovers some new low mass states and 3. LHC discovers new heavy particles. We will show that in each case, ILC plays a critical role in discovery of new phenomena and in pushing forward the frontiers of high-energy physics as well as our understanding of the universe in a manner which is highly complementary to that of LHC. For the busy reader, a two-page executive summary is provided at the beginning of the document.

The potential of the ILC for discovering new particles

International Nuclear Information System (INIS)

Fujii, Keisuke; Grojean, Christophe; Peskin, Michael E.

2017-02-01

This paper addresses the question of whether the International Linear Collider has the capability of discovering new particles that have not already been discovered at the CERN Large Hadron Collider. We summarize the various paths to discovery offered by the ILC, and discuss them in the context of three different scenarios: 1. LHC does not discover any new particles, 2. LHC discovers some new low mass states and 3. LHC discovers new heavy particles. We will show that in each case, ILC plays a critical role in discovery of new phenomena and in pushing forward the frontiers of high-energy physics as well as our understanding of the universe in a manner which is highly complementary to that of LHC. For the busy reader, a two-page executive summary is provided at the beginning of the document.

Contribution of large-scale circulation anomalies to changes in extreme precipitation frequency in the United States

International Nuclear Information System (INIS)

Yu, Lejiang; Zhong, Shiyuan; Pei, Lisi; Bian, Xindi; Heilman, Warren E

2016-01-01

The mean global climate has warmed as a result of the increasing emission of greenhouse gases induced by human activities. This warming is considered the main reason for the increasing number of extreme precipitation events in the US. While much attention has been given to extreme precipitation events occurring over several days, which are usually responsible for severe flooding over a large region, little is known about how extreme precipitation events that cause flash flooding and occur at sub-daily time scales have changed over time. Here we use the observed hourly precipitation from the North American Land Data Assimilation System Phase 2 forcing datasets to determine trends in the frequency of extreme precipitation events of short (1 h, 3 h, 6 h, 12 h and 24 h) duration for the period 1979–2013. The results indicate an increasing trend in the central and eastern US. Over most of the western US, especially the Southwest and the Intermountain West, the trends are generally negative. These trends can be largely explained by the interdecadal variability of the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation (AMO), with the AMO making a greater contribution to the trends in both warm and cold seasons. (letter)

Extremely large magnetoresistance in few-layer graphene/boron-nitride heterostructures.

Science.gov (United States)

Gopinadhan, Kalon; Shin, Young Jun; Jalil, Rashid; Venkatesan, Thirumalai; Geim, Andre K; Castro Neto, Antonio H; Yang, Hyunsoo

2015-09-21

Understanding magnetoresistance, the change in electrical resistance under an external magnetic field, at the atomic level is of great interest both fundamentally and technologically. Graphene and other two-dimensional layered materials provide an unprecedented opportunity to explore magnetoresistance at its nascent stage of structural formation. Here we report an extremely large local magnetoresistance of ∼2,000% at 400 K and a non-local magnetoresistance of >90,000% in an applied magnetic field of 9 T at 300 K in few-layer graphene/boron-nitride heterostructures. The local magnetoresistance is understood to arise from large differential transport parameters, such as the carrier mobility, across various layers of few-layer graphene upon a normal magnetic field, whereas the non-local magnetoresistance is due to the magnetic field induced Ettingshausen-Nernst effect. Non-local magnetoresistance suggests the possibility of a graphene-based gate tunable thermal switch. In addition, our results demonstrate that graphene heterostructures may be promising for magnetic field sensing applications.

Coupled large-eddy simulation and morphodynamics of a large-scale river under extreme flood conditions

Science.gov (United States)

Khosronejad, Ali; Sotiropoulos, Fotis; Stony Brook University Team

2016-11-01

We present a coupled flow and morphodynamic simulations of extreme flooding in 3 km long and 300 m wide reach of the Mississippi River in Minnesota, which includes three islands and hydraulic structures. We employ the large-eddy simulation (LES) and bed-morphodynamic modules of the VFS-Geophysics model to investigate the flow and bed evolution of the river during a 500 year flood. The coupling of the two modules is carried out via a fluid-structure interaction approach using a nested domain approach to enhance the resolution of bridge scour predictions. The geometrical data of the river, islands and structures are obtained from LiDAR, sub-aqueous sonar and in-situ surveying to construct a digital map of the river bathymetry. Our simulation results for the bed evolution of the river reveal complex sediment dynamics near the hydraulic structures. The numerically captured scour depth near some of the structures reach a maximum of about 10 m. The data-driven simulation strategy we present in this work exemplifies a practical simulation-based-engineering-approach to investigate the resilience of infrastructures to extreme flood events in intricate field-scale riverine systems. This work was funded by a Grant from Minnesota Dept. of Transportation.

Forcings and feedbacks on convection in the 2010 Pakistan flood: Modeling extreme precipitation with interactive large-scale ascent

Science.gov (United States)

Nie, Ji; Shaevitz, Daniel A.; Sobel, Adam H.

2016-09-01

Extratropical extreme precipitation events are usually associated with large-scale flow disturbances, strong ascent, and large latent heat release. The causal relationships between these factors are often not obvious, however, the roles of different physical processes in producing the extreme precipitation event can be difficult to disentangle. Here we examine the large-scale forcings and convective heating feedback in the precipitation events, which caused the 2010 Pakistan flood within the Column Quasi-Geostrophic framework. A cloud-revolving model (CRM) is forced with large-scale forcings (other than large-scale vertical motion) computed from the quasi-geostrophic omega equation using input data from a reanalysis data set, and the large-scale vertical motion is diagnosed interactively with the simulated convection. Numerical results show that the positive feedback of convective heating to large-scale dynamics is essential in amplifying the precipitation intensity to the observed values. Orographic lifting is the most important dynamic forcing in both events, while differential potential vorticity advection also contributes to the triggering of the first event. Horizontal moisture advection modulates the extreme events mainly by setting the environmental humidity, which modulates the amplitude of the convection's response to the dynamic forcings. When the CRM is replaced by either a single-column model (SCM) with parameterized convection or a dry model with a reduced effective static stability, the model results show substantial discrepancies compared with reanalysis data. The reasons for these discrepancies are examined, and the implications for global models and theoretical models are discussed.

High-z X-ray Obscured Quasars in Galaxies with Extreme Mid-IR/Optical Colors

Science.gov (United States)

Piconcelli, E.; Lanzuisi, G.; Fiore, F.; Feruglio, C.; Vignali, C.; Salvato, M.; Grappioni, C.

2009-05-01

Extreme Optical/Mid-IR color cuts have been used to uncover a population of dust-enshrouded, mid-IR luminous galaxies at high redshifts. Several lines of evidence point towards the presence of an heavily absorbed, possibly Compton-thick quasar at the heart of these systems. Nonetheless, the X-ray spectral properties of these intriguing sources still remain largely unexplored. Here we present an X-ray spectroscopic study of a large sample of 44 extreme dust-obscured galaxies (EDOGs) with F24 μm/FR>2000 and F24 μm>1.3 mJy selected from a 6 deg2 region in the SWIRE fields. The application of our selection criteria to a wide area survey has been capable of unveiling a population of X-ray luminous, absorbed z>1 quasars which is mostly missed in the traditional optical/X-ray surveys performed so far. Advances in the understanding of the X-ray properties of these recently-discovered sources by Simbol-X observations will be also discussed.

Wind and wave extremes over the world oceans from very large ensembles

Science.gov (United States)

Breivik, Øyvind; Aarnes, Ole Johan; Abdalla, Saleh; Bidlot, Jean-Raymond; Janssen, Peter A. E. M.

2014-07-01

Global return values of marine wind speed and significant wave height are estimated from very large aggregates of archived ensemble forecasts at +240 h lead time. Long lead time ensures that the forecasts represent independent draws from the model climate. Compared with ERA-Interim, a reanalysis, the ensemble yields higher return estimates for both wind speed and significant wave height. Confidence intervals are much tighter due to the large size of the data set. The period (9 years) is short enough to be considered stationary even with climate change. Furthermore, the ensemble is large enough for nonparametric 100 year return estimates to be made from order statistics. These direct return estimates compare well with extreme value estimates outside areas with tropical cyclones. Like any method employing modeled fields, it is sensitive to tail biases in the numerical model, but we find that the biases are moderate outside areas with tropical cyclones.

Parallel multiple instance learning for extremely large histopathology image analysis.

Science.gov (United States)

Xu, Yan; Li, Yeshu; Shen, Zhengyang; Wu, Ziwei; Gao, Teng; Fan, Yubo; Lai, Maode; Chang, Eric I-Chao

2017-08-03

Histopathology images are critical for medical diagnosis, e.g., cancer and its treatment. A standard histopathology slice can be easily scanned at a high resolution of, say, 200,000×200,000 pixels. These high resolution images can make most existing imaging processing tools infeasible or less effective when operated on a single machine with limited memory, disk space and computing power. In this paper, we propose an algorithm tackling this new emerging "big data" problem utilizing parallel computing on High-Performance-Computing (HPC) clusters. Experimental results on a large-scale data set (1318 images at a scale of 10 billion pixels each) demonstrate the efficiency and effectiveness of the proposed algorithm for low-latency real-time applications. The framework proposed an effective and efficient system for extremely large histopathology image analysis. It is based on the multiple instance learning formulation for weakly-supervised learning for image classification, segmentation and clustering. When a max-margin concept is adopted for different clusters, we obtain further improvement in clustering performance.

Discovering Technicolor

DEFF Research Database (Denmark)

R. Andersen, J.; Antipin, O.; Azuelos, G.

2011-01-01

We provide a pedagogical introduction to extensions of the Standard Model in which the Higgs is composite. These extensions are known as models of dynamical electroweak symmetry breaking or, in brief, Technicolor. Material covered includes: motivations for Technicolor, the construction of underly...... the relevant experimental benchmarks for Vanilla, Running, Walking, and Custodial Technicolor, and a natural fourth family of leptons, by laying out the framework to discover these models at the Large Hadron Collider....... of underlying gauge theories leading to minimal models of Technicolor, the comparison with electroweak precision data, the low energy effective theory, the spectrum of the states common to most of the Technicolor models, the decays of the composite particles and the experimental signals at the Large Hadron...... Collider. The level of the presentation is aimed at readers familiar with the Standard Model but who have little or no prior exposure to Technicolor. Several extensions of the Standard Model featuring a composite Higgs can be reduced to the effective Lagrangian introduced in the text. We establish...

A Large-Scale Multi-Hop Localization Algorithm Based on Regularized Extreme Learning for Wireless Networks.

Science.gov (United States)

Zheng, Wei; Yan, Xiaoyong; Zhao, Wei; Qian, Chengshan

2017-12-20

A novel large-scale multi-hop localization algorithm based on regularized extreme learning is proposed in this paper. The large-scale multi-hop localization problem is formulated as a learning problem. Unlike other similar localization algorithms, the proposed algorithm overcomes the shortcoming of the traditional algorithms which are only applicable to an isotropic network, therefore has a strong adaptability to the complex deployment environment. The proposed algorithm is composed of three stages: data acquisition, modeling and location estimation. In data acquisition stage, the training information between nodes of the given network is collected. In modeling stage, the model among the hop-counts and the physical distances between nodes is constructed using regularized extreme learning. In location estimation stage, each node finds its specific location in a distributed manner. Theoretical analysis and several experiments show that the proposed algorithm can adapt to the different topological environments with low computational cost. Furthermore, high accuracy can be achieved by this method without setting complex parameters.

Extremely large magnetoresistance and electronic structure of TmSb

Science.gov (United States)

Wang, Yi-Yan; Zhang, Hongyun; Lu, Xiao-Qin; Sun, Lin-Lin; Xu, Sheng; Lu, Zhong-Yi; Liu, Kai; Zhou, Shuyun; Xia, Tian-Long

2018-02-01

We report the magnetotransport properties and the electronic structure of TmSb. TmSb exhibits extremely large transverse magnetoresistance and Shubnikov-de Haas (SdH) oscillation at low temperature and high magnetic field. Interestingly, the split of Fermi surfaces induced by the nonsymmetric spin-orbit interaction has been observed from SdH oscillation. The analysis of the angle-dependent SdH oscillation illustrates the contribution of each Fermi surface to the conductivity. The electronic structure revealed by angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations demonstrates a gap at the X point and the absence of band inversion. Combined with the trivial Berry phase extracted from SdH oscillation and the nearly equal concentrations of electron and hole from Hall measurements, it is suggested that TmSb is a topologically trivial semimetal and the observed XMR originates from the electron-hole compensation and high mobility.

Distant Galaxy Clusters Hosting Extreme Central Galaxies

Science.gov (United States)

McDonald, Michael

2014-09-01

The recently-discovered Phoenix cluster harbors the most star-forming central cluster galaxy of any cluster in the known Universe, by nearly a factor of 10. This extreme system appears to be fulfilling early cooling flow predictions, although the lack of similar systems makes any interpretation difficult. In an attempt to find other "Phoenix-like" clusters, we have cross-correlated archival all-sky surveys (in which Phoenix was detected) and isolated 4 similarly-extreme systems which are also coincident in position and redshift with an overdensity of red galaxies. We propose here to obtain Chandra observations of these extreme, Phoenix-like systems, in order to confirm them as relaxed, rapidly-cooling galaxy clusters.

Transumbilical single-site laparoscopy takes the advantage of ultraminilaparotomy in managing an extremely large ovarian cyst

Directory of Open Access Journals (Sweden)

Hsuan Su

2012-11-01

Conclusion: This application not only provides both advantages of ultraminilaparotomy and laparoscopy but it also overcomes the limitations of both approaches. Therefore, it is the surgical approach of choice for a patient bearing an extremely large ovarian cystic tumor.

An extremely bright gamma-ray pulsar in the Large Magellanic Cloud.

Science.gov (United States)

2015-11-13

Pulsars are rapidly spinning, highly magnetized neutron stars, created in the gravitational collapse of massive stars. We report the detection of pulsed giga-electron volt gamma rays from the young pulsar PSR J0540-6919 in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. This is the first gamma-ray pulsar detected in another galaxy. It has the most luminous pulsed gamma-ray emission yet observed, exceeding the Crab pulsar's by a factor of 20. PSR J0540-6919 presents an extreme test case for understanding the structure and evolution of neutron star magnetospheres. Copyright © 2015, American Association for the Advancement of Science.

Spatial extreme value analysis to project extremes of large-scale indicators for severe weather.

Science.gov (United States)

Gilleland, Eric; Brown, Barbara G; Ammann, Caspar M

2013-09-01

Concurrently high values of the maximum potential wind speed of updrafts ( W max ) and 0-6 km wind shear (Shear) have been found to represent conducive environments for severe weather, which subsequently provides a way to study severe weather in future climates. Here, we employ a model for the product of these variables (WmSh) from the National Center for Atmospheric Research/United States National Center for Environmental Prediction reanalysis over North America conditioned on their having extreme energy in the spatial field in order to project the predominant spatial patterns of WmSh. The approach is based on the Heffernan and Tawn conditional extreme value model. Results suggest that this technique estimates the spatial behavior of WmSh well, which allows for exploring possible changes in the patterns over time. While the model enables a method for inferring the uncertainty in the patterns, such analysis is difficult with the currently available inference approach. A variation of the method is also explored to investigate how this type of model might be used to qualitatively understand how the spatial patterns of WmSh correspond to extreme river flow events. A case study for river flows from three rivers in northwestern Tennessee is studied, and it is found that advection of WmSh from the Gulf of Mexico prevails while elsewhere, WmSh is generally very low during such extreme events. © 2013 The Authors. Environmetrics published by JohnWiley & Sons, Ltd.

High resolution spectroscopy of six new extreme helium stars

Science.gov (United States)

Heber, U.; Jones, G.; Drilling, J. S.

1986-01-01

High resolution spectra of six newly discovered extreme helium stars are presented. LSS 5121 is shown to be a spectroscopical twin of the hot extreme helium star HD 160641. A preliminary LTE analysis of LSS 3184 yielded an effective temperature of 22,000 K and a surface gravity of log g = 3.2. Four stars form a new subgroup, classified by sharp-lined He I spectra and pronounced O II spectra, and it is conjectured that these lie close to the Eddington limit. The whole group of extreme helium stars apparently is inhomogeneous with respect to luminosity to mass ratio and chemical composition.

Extreme weather events in southern Germany - Climatological risk and development of a large-scale identification procedure

Science.gov (United States)

Matthies, A.; Leckebusch, G. C.; Rohlfing, G.; Ulbrich, U.

2009-04-01

Extreme weather events such as thunderstorms, hail and heavy rain or snowfall can pose a threat to human life and to considerable tangible assets. Yet there is a lack of knowledge about present day climatological risk and its economic effects, and its changes due to rising greenhouse gas concentrations. Therefore, parts of economy particularly sensitve to extreme weather events such as insurance companies and airports require regional risk-analyses, early warning and prediction systems to cope with such events. Such an attempt is made for southern Germany, in close cooperation with stakeholders. Comparing ERA40 and station data with impact records of Munich Re and Munich Airport, the 90th percentile was found to be a suitable threshold for extreme impact relevant precipitation events. Different methods for the classification of causing synoptic situations have been tested on ERA40 reanalyses. An objective scheme for the classification of Lamb's circulation weather types (CWT's) has proved to be most suitable for correct classification of the large-scale flow conditions. Certain CWT's have been turned out to be prone to heavy precipitation or on the other side to have a very low risk of such events. Other large-scale parameters are tested in connection with CWT's to find out a combination that has the highest skill to identify extreme precipitation events in climate model data (ECHAM5 and CLM). For example vorticity advection in 700 hPa shows good results, but assumes knowledge of regional orographic particularities. Therefore ongoing work is focused on additional testing of parameters that indicate deviations of a basic state of the atmosphere like the Eady Growth Rate or the newly developed Dynamic State Index. Evaluation results will be used to estimate the skill of the regional climate model CLM concerning the simulation of frequency and intensity of the extreme weather events. Data of the A1B scenario (2000-2050) will be examined for a possible climate change

A large, benign prostatic cyst presented with an extremely high serum prostate-specific antigen level.

Science.gov (United States)

Chen, Han-Kuang; Pemberton, Richard

2016-01-08

We report a case of a patient who presented with an extremely high serum prostate specific antigen (PSA) level and underwent radical prostatectomy for presumed prostate cancer. Surprisingly, the whole mount prostatectomy specimen showed only small volume, organ-confined prostate adenocarcinoma and a large, benign intraprostatic cyst, which was thought to be responsible for the PSA elevation. 2016 BMJ Publishing Group Ltd.

Development of an Evaluation Methodology for Loss of Large Area induced from extreme events

International Nuclear Information System (INIS)

Kim, Sok Chul; Park, Jong Seuk; Kim, Byung Soon; Jang, Dong Ju; Lee, Seung Woo

2015-01-01

USNRC announced several regulatory requirements and guidance documents regarding the event of loss of large area including 10CFR 50.54(hh), Regulatory Guide 1.214 and SRP 19.4. In Korea, consideration of loss of large area has been limitedly taken into account for newly constructing NPPs as voluntary based. In general, it is hardly possible to find available information on methodology and key assumptions for the assessment of LOLA due to 'need to know based approach'. Urgent needs exists for developing country specific regulatory requirements, guidance and evaluation methodology by themselves with the consideration of their own geographical and nuclear safety and security environments. Currently, Korea Hydro and Nuclear Power Company (KHNP) has developed an Extended Damage Mitigation Guideline (EDMG) for APR1400 under contract with foreign consulting company. The submittal guidance NEI 06-12 related to B.5.b Phase 2 and 3 focused on unit-wise mitigation strategy instead of site level mitigation or response strategy. Phase 1 mitigating strategy and guideline for LOLA (Loss of Large Area) provides emphasis on site level arrangement including cooperative networking outside organizations and agile command and control system. Korea Institute of Nuclear Safety has carried out a pilot in-house research project to develop the methodology and guideline for evaluation of LOLA since 2014. This paper introduces the summary of major results and outcomes of the aforementioned research project. After Fukushima Dai-Ichi accident, the awareness on countering the event of loss of large area induced from extreme man-made hazards or extreme beyond design basis external event. Urgent need exists to develop regulatory guidance for coping with this undesirable situation, which has been out of consideration at existing nuclear safety regulatory framework due to the expectation of rare possibility of occurrence

Neutron Star Astronomy in the era of the European Extremely Large Telescope

International Nuclear Information System (INIS)

Mignani, Roberto P.

2011-01-01

About 25 isolated neutron stars (INSs) are now detected in the optical domain, mainly thanks to the HST and to VLT-class telescopes. The European Extremely Large Telescope(E-ELT) will yield ∼100 new identifications, many of which from the follow-up of SKA, IXO, and Fermi observations. Moreover, the E-ELT will allow to carry out, on a much larger sample, INS observations which still challenge VLT-class telescopes, enabling studies on the structure and composition of the NS interior, of its atmosphere and magnetosphere, as well as to search for debris discs. In this contribution, I outline future perspectives for NS optical astronomy with the E-ELT.

Contribution of large-scale midlatitude disturbances to hourly precipitation extremes in the United States

Science.gov (United States)

Barbero, Renaud; Abatzoglou, John T.; Fowler, Hayley J.

2018-02-01

Midlatitude synoptic weather regimes account for a substantial portion of annual precipitation accumulation as well as multi-day precipitation extremes across parts of the United States (US). However, little attention has been devoted to understanding how synoptic-scale patterns contribute to hourly precipitation extremes. A majority of 1-h annual maximum precipitation (AMP) across the western US were found to be linked to two coherent midlatitude synoptic patterns: disturbances propagating along the jet stream, and cutoff upper-level lows. The influence of these two patterns on 1-h AMP varies geographically. Over 95% of 1-h AMP along the western coastal US were coincident with progressive midlatitude waves embedded within the jet stream, while over 30% of 1-h AMP across the interior western US were coincident with cutoff lows. Between 30-60% of 1-h AMP were coincident with the jet stream across the Ohio River Valley and southeastern US, whereas a a majority of 1-h AMP over the rest of central and eastern US were not found to be associated with either midlatitude synoptic features. Composite analyses for 1-h AMP days coincident to cutoff lows and jet stream show that an anomalous moisture flux and upper-level dynamics are responsible for initiating instability and setting up an environment conducive to 1-h AMP events. While hourly precipitation extremes are generally thought to be purely convective in nature, this study shows that large-scale dynamics and baroclinic disturbances may also contribute to precipitation extremes on sub-daily timescales.

Computational discovery of extremal microstructure families

Science.gov (United States)

Chen, Desai; Skouras, Mélina; Zhu, Bo; Matusik, Wojciech

2018-01-01

Modern fabrication techniques, such as additive manufacturing, can be used to create materials with complex custom internal structures. These engineered materials exhibit a much broader range of bulk properties than their base materials and are typically referred to as metamaterials or microstructures. Although metamaterials with extraordinary properties have many applications, designing them is very difficult and is generally done by hand. We propose a computational approach to discover families of microstructures with extremal macroscale properties automatically. Using efficient simulation and sampling techniques, we compute the space of mechanical properties covered by physically realizable microstructures. Our system then clusters microstructures with common topologies into families. Parameterized templates are eventually extracted from families to generate new microstructure designs. We demonstrate these capabilities on the computational design of mechanical metamaterials and present five auxetic microstructure families with extremal elastic material properties. Our study opens the way for the completely automated discovery of extremal microstructures across multiple domains of physics, including applications reliant on thermal, electrical, and magnetic properties. PMID:29376124

Einstein@Home discovers a radio-quiet gamma-ray millisecond pulsar.

Science.gov (United States)

Clark, Colin J; Pletsch, Holger J; Wu, Jason; Guillemot, Lucas; Kerr, Matthew; Johnson, Tyrel J; Camilo, Fernando; Salvetti, David; Allen, Bruce; Anderson, David; Aulbert, Carsten; Beer, Christian; Bock, Oliver; Cuéllar, Andres; Eggenstein, Heinz-Bernd; Fehrmann, Henning; Kramer, Michael; Kwang, Shawn A; Machenschalk, Bernd; Nieder, Lars; Ackermann, Markus; Ajello, Marco; Baldini, Luca; Ballet, Jean; Barbiellini, Guido; Bastieri, Denis; Bellazzini, Ronaldo; Bissaldi, Elisabetta; Blandford, Roger D; Bloom, Elliott D; Bonino, Raffaella; Bottacini, Eugenio; Brandt, Terri J; Bregeon, Johan; Bruel, Philippe; Buehler, Rolf; Burnett, Toby H; Buson, Sara; Cameron, Rob A; Caputo, Regina; Caraveo, Patrizia A; Cavazzuti, Elisabetta; Cecchi, Claudia; Charles, Eric; Chekhtman, Alexandre; Ciprini, Stefano; Cominsky, Lynn R; Costantin, Denise; Cutini, Sara; D'Ammando, Filippo; De Luca, Andrea; Desiante, Rachele; Di Venere, Leonardo; Di Mauro, Mattia; Di Lalla, Niccolò; Digel, Seth W; Favuzzi, Cecilia; Ferrara, Elizabeth C; Franckowiak, Anna; Fukazawa, Yasushi; Funk, Stefan; Fusco, Piergiorgio; Gargano, Fabio; Gasparrini, Dario; Giglietto, Nico; Giordano, Francesco; Giroletti, Marcello; Gomez-Vargas, Germán A; Green, David; Grenier, Isabelle A; Guiriec, Sylvain; Harding, Alice K; Hewitt, John W; Horan, Deirdre; Jóhannesson, Guðlaugur; Kensei, Shiki; Kuss, Michael; La Mura, Giovanni; Larsson, Stefan; Latronico, Luca; Li, Jian; Longo, Francesco; Loparco, Francesco; Lovellette, Michael N; Lubrano, Pasquale; Magill, Jeffrey D; Maldera, Simone; Manfreda, Alberto; Mazziotta, Mario N; McEnery, Julie E; Michelson, Peter F; Mirabal, Nestor; Mitthumsiri, Warit; Mizuno, Tsunefumi; Monzani, Maria Elena; Morselli, Aldo; Moskalenko, Igor V; Nuss, Eric; Ohsugi, Takashi; Omodei, Nicola; Orienti, Monica; Orlando, Elena; Palatiello, Michele; Paliya, Vaidehi S; de Palma, Francesco; Paneque, David; Perkins, Jeremy S; Persic, Massimo; Pesce-Rollins, Melissa; Porter, Troy A; Principe, Giacomo; Rainò, Silvia; Rando, Riccardo; Ray, Paul S; Razzano, Massimiliano; Reimer, Anita; Reimer, Olaf; Romani, Roger W; Saz Parkinson, Pablo M; Sgrò, Carmelo; Siskind, Eric J; Smith, David A; Spada, Francesca; Spandre, Gloria; Spinelli, Paolo; Thayer, Jana B; Thompson, David J; Torres, Diego F; Troja, Eleonora; Vianello, Giacomo; Wood, Kent; Wood, Matthew

2018-02-01

Millisecond pulsars (MSPs) are old neutron stars that spin hundreds of times per second and appear to pulsate as their emission beams cross our line of sight. To date, radio pulsations have been detected from all rotation-powered MSPs. In an attempt to discover radio-quiet gamma-ray MSPs, we used the aggregated power from the computers of tens of thousands of volunteers participating in the Einstein@Home distributed computing project to search for pulsations from unidentified gamma-ray sources in Fermi Large Area Telescope data. This survey discovered two isolated MSPs, one of which is the only known rotation-powered MSP to remain undetected in radio observations. These gamma-ray MSPs were discovered in completely blind searches without prior constraints from other observations, raising hopes for detecting MSPs from a predicted Galactic bulge population.

BAL QSOs and Extreme UFOs: The Eddington Connection

Science.gov (United States)

Zubovas, Kastytis; King, Andrew

2013-05-01

We suggest a common physical origin connecting the fast, highly ionized winds (UFOs) seen in nearby active galactic nuclei (AGNs), and the slower and less ionized winds of broad absorption line (BAL) QSOs. The primary difference is the mass-loss rate in the wind, which is ultimately determined by the rate at which mass is fed toward the central supermassive black hole (SMBH) on large scales. This is below the Eddington accretion rate in most UFOs, and slightly super-Eddington in extreme UFOs such as PG1211+143, but ranges up to ~10-50 times this in BAL QSOs. For UFOs this implies black hole accretion rates and wind mass-loss rates which are at most comparable to Eddington, giving fast, highly ionized winds. In contrast, BAL QSO black holes have mildly super-Eddington accretion rates, and drive winds whose mass-loss rates are significantly super-Eddington, and so are slower and less ionized. This picture correctly predicts the velocities and ionization states of the observed winds, including the recently discovered one in SDSS J1106+1939. We suggest that luminous AGNs may evolve through a sequence from BAL QSO through LoBAL to UFO-producing Seyfert or quasar as their Eddington factors drop during the decay of a bright accretion event. LoBALs correspond to a short-lived stage in which the AGN radiation pressure largely evacuates the ionization cone, but before the large-scale accretion rate has dropped to the Eddington value. We show that sub-Eddington wind rates would produce an M-σ relation lying above that observed. We conclude that significant SMBH mass growth must occur in super-Eddington phases, either as BAL QSOs, extreme UFOs, or obscured from direct observation.

BAL QSOs AND EXTREME UFOs: THE EDDINGTON CONNECTION

International Nuclear Information System (INIS)

Zubovas, Kastytis; King, Andrew

2013-01-01

We suggest a common physical origin connecting the fast, highly ionized winds (UFOs) seen in nearby active galactic nuclei (AGNs), and the slower and less ionized winds of broad absorption line (BAL) QSOs. The primary difference is the mass-loss rate in the wind, which is ultimately determined by the rate at which mass is fed toward the central supermassive black hole (SMBH) on large scales. This is below the Eddington accretion rate in most UFOs, and slightly super-Eddington in extreme UFOs such as PG1211+143, but ranges up to ∼10-50 times this in BAL QSOs. For UFOs this implies black hole accretion rates and wind mass-loss rates which are at most comparable to Eddington, giving fast, highly ionized winds. In contrast, BAL QSO black holes have mildly super-Eddington accretion rates, and drive winds whose mass-loss rates are significantly super-Eddington, and so are slower and less ionized. This picture correctly predicts the velocities and ionization states of the observed winds, including the recently discovered one in SDSS J1106+1939. We suggest that luminous AGNs may evolve through a sequence from BAL QSO through LoBAL to UFO-producing Seyfert or quasar as their Eddington factors drop during the decay of a bright accretion event. LoBALs correspond to a short-lived stage in which the AGN radiation pressure largely evacuates the ionization cone, but before the large-scale accretion rate has dropped to the Eddington value. We show that sub-Eddington wind rates would produce an M-σ relation lying above that observed. We conclude that significant SMBH mass growth must occur in super-Eddington phases, either as BAL QSOs, extreme UFOs, or obscured from direct observation.

BAL QSOs AND EXTREME UFOs: THE EDDINGTON CONNECTION

Energy Technology Data Exchange (ETDEWEB)

Zubovas, Kastytis; King, Andrew, E-mail: kastytis.zubovas@ftmc.lt [Theoretical Astrophysics Group, University of Leicester, Leicester LE1 7RH (United Kingdom)

2013-05-20

We suggest a common physical origin connecting the fast, highly ionized winds (UFOs) seen in nearby active galactic nuclei (AGNs), and the slower and less ionized winds of broad absorption line (BAL) QSOs. The primary difference is the mass-loss rate in the wind, which is ultimately determined by the rate at which mass is fed toward the central supermassive black hole (SMBH) on large scales. This is below the Eddington accretion rate in most UFOs, and slightly super-Eddington in extreme UFOs such as PG1211+143, but ranges up to {approx}10-50 times this in BAL QSOs. For UFOs this implies black hole accretion rates and wind mass-loss rates which are at most comparable to Eddington, giving fast, highly ionized winds. In contrast, BAL QSO black holes have mildly super-Eddington accretion rates, and drive winds whose mass-loss rates are significantly super-Eddington, and so are slower and less ionized. This picture correctly predicts the velocities and ionization states of the observed winds, including the recently discovered one in SDSS J1106+1939. We suggest that luminous AGNs may evolve through a sequence from BAL QSO through LoBAL to UFO-producing Seyfert or quasar as their Eddington factors drop during the decay of a bright accretion event. LoBALs correspond to a short-lived stage in which the AGN radiation pressure largely evacuates the ionization cone, but before the large-scale accretion rate has dropped to the Eddington value. We show that sub-Eddington wind rates would produce an M-{sigma} relation lying above that observed. We conclude that significant SMBH mass growth must occur in super-Eddington phases, either as BAL QSOs, extreme UFOs, or obscured from direct observation.

Einstein@Home discovers a radio-quiet gamma-ray millisecond pulsar

Science.gov (United States)

Clark, Colin J.; Pletsch, Holger J.; Wu, Jason; Guillemot, Lucas; Kerr, Matthew; Johnson, Tyrel J.; Camilo, Fernando; Salvetti, David; Allen, Bruce; Anderson, David; Aulbert, Carsten; Beer, Christian; Bock, Oliver; Cuéllar, Andres; Eggenstein, Heinz-Bernd; Fehrmann, Henning; Kramer, Michael; Kwang, Shawn A.; Machenschalk, Bernd; Nieder, Lars; Ackermann, Markus; Ajello, Marco; Baldini, Luca; Ballet, Jean; Barbiellini, Guido; Bastieri, Denis; Bellazzini, Ronaldo; Bissaldi, Elisabetta; Blandford, Roger D.; Bloom, Elliott D.; Bonino, Raffaella; Bottacini, Eugenio; Brandt, Terri J.; Bregeon, Johan; Bruel, Philippe; Buehler, Rolf; Burnett, Toby H.; Buson, Sara; Cameron, Rob A.; Caputo, Regina; Caraveo, Patrizia A.; Cavazzuti, Elisabetta; Cecchi, Claudia; Charles, Eric; Chekhtman, Alexandre; Ciprini, Stefano; Cominsky, Lynn R.; Costantin, Denise; Cutini, Sara; D’Ammando, Filippo; De Luca, Andrea; Desiante, Rachele; Di Venere, Leonardo; Di Mauro, Mattia; Di Lalla, Niccolò; Digel, Seth W.; Favuzzi, Cecilia; Ferrara, Elizabeth C.; Franckowiak, Anna; Fukazawa, Yasushi; Funk, Stefan; Fusco, Piergiorgio; Gargano, Fabio; Gasparrini, Dario; Giglietto, Nico; Giordano, Francesco; Giroletti, Marcello; Gomez-Vargas, Germán A.; Green, David; Grenier, Isabelle A.; Guiriec, Sylvain; Harding, Alice K.; Hewitt, John W.; Horan, Deirdre; Jóhannesson, Guðlaugur; Kensei, Shiki; Kuss, Michael; La Mura, Giovanni; Larsson, Stefan; Latronico, Luca; Li, Jian; Longo, Francesco; Loparco, Francesco; Lovellette, Michael N.; Lubrano, Pasquale; Magill, Jeffrey D.; Maldera, Simone; Manfreda, Alberto; Mazziotta, Mario N.; McEnery, Julie E.; Michelson, Peter F.; Mirabal, Nestor; Mitthumsiri, Warit; Mizuno, Tsunefumi; Monzani, Maria Elena; Morselli, Aldo; Moskalenko, Igor V.; Nuss, Eric; Ohsugi, Takashi; Omodei, Nicola; Orienti, Monica; Orlando, Elena; Palatiello, Michele; Paliya, Vaidehi S.; de Palma, Francesco; Paneque, David; Perkins, Jeremy S.; Persic, Massimo; Pesce-Rollins, Melissa; Porter, Troy A.; Principe, Giacomo; Rainò, Silvia; Rando, Riccardo; Ray, Paul S.; Razzano, Massimiliano; Reimer, Anita; Reimer, Olaf; Romani, Roger W.; Saz Parkinson, Pablo M.; Sgrò, Carmelo; Siskind, Eric J.; Smith, David A.; Spada, Francesca; Spandre, Gloria; Spinelli, Paolo; Thayer, Jana B.; Thompson, David J.; Torres, Diego F.; Troja, Eleonora; Vianello, Giacomo; Wood, Kent; Wood, Matthew

2018-01-01

Millisecond pulsars (MSPs) are old neutron stars that spin hundreds of times per second and appear to pulsate as their emission beams cross our line of sight. To date, radio pulsations have been detected from all rotation-powered MSPs. In an attempt to discover radio-quiet gamma-ray MSPs, we used the aggregated power from the computers of tens of thousands of volunteers participating in the Einstein@Home distributed computing project to search for pulsations from unidentified gamma-ray sources in Fermi Large Area Telescope data. This survey discovered two isolated MSPs, one of which is the only known rotation-powered MSP to remain undetected in radio observations. These gamma-ray MSPs were discovered in completely blind searches without prior constraints from other observations, raising hopes for detecting MSPs from a predicted Galactic bulge population. PMID:29503868

PALFA Discovers Neutron Stars on a Collision Course

Science.gov (United States)

Kohler, Susanna

2018-03-01

Got any plans in 46 million years? If not, you should keep an eye out for PSR J1946+2052 around that time this upcoming merger of two neutron stars promises to be an exciting show!Survey SuccessAverage profile for PSR J1946+2052 at 1.43 GHz from a 2 hr observation from the Arecibo Observatory. [Stovall et al. 2018]It seems like we just wrote about the dearth of known double-neutron-star systems, and about how new surveys are doing their best to find more of these compact binaries. Observing these systems improves our knowledge of how pairs of evolved stars behave before they eventually spiral in, merge, and emit gravitational waves that detectors like the Laser Interferometer Gravitational-wave Observatory might observe.Todays study, led by Kevin Stovall (National Radio Astronomy Observatory), goes to show that these surveys are doing a great job so far! Yet another double-neutron-star binary, PSR J1946+2052, has now been discovered as part of the Arecibo L-Band Feed Array pulsar (PALFA) survey. This one is especially unique due to the incredible speed with which these neutron stars orbit each other and their correspondingly (relatively!) short timescale for merger.An Extreme ExampleThe PALFA survey, conducted with the enormous 305-meter radio dish at Arecibo, has thus far resulted in the discovery of 180 pulsars including two double-neutron-star systems. The most recent discovery by Stovall and collaborators brings that number up to three, for a grand total of 16 binary-neutron-star systems (confirmed and unconfirmed) known to date.The 305-m Arecibo Radio Telescope, built into the landscape at Arecibo, Puerto Rico. [NOAO/AURA/NSF/H. Schweiker/WIYN]The newest binary in this collection, PSR J1946+2052, exhibits a pulsar with a 17-millisecond spin period thatwhips around its compact companion at a terrifying rate: the binary period is just 1.88 hours. Follow-up observations with the Jansky Very Large Array and other telescopes allowed the team to identify the binarys

A Green Bank Telescope Survey of Large Galactic H II Regions

Science.gov (United States)

Anderson, L. D.; Armentrout, W. P.; Luisi, Matteo; Bania, T. M.; Balser, Dana S.; Wenger, Trey V.

2018-02-01

As part of our ongoing H II Region Discovery Survey (HRDS), we report the Green Bank Telescope detection of 148 new angularly large Galactic H II regions in radio recombination line (RRL) emission. Our targets are located at a declination of δ > -45^\\circ , which corresponds to 266^\\circ > {\\ell }> -20^\\circ at b=0^\\circ . All sources were selected from the Wide-field Infrared Survey Explorer Catalog of Galactic H II Regions, and have infrared angular diameters ≥slant 260\\prime\\prime . The Galactic distribution of these “large” H II regions is similar to that of the previously known sample of Galactic H II regions. The large H II region RRL line width and peak line intensity distributions are skewed toward lower values, compared with that of previous HRDS surveys. We discover seven sources with extremely narrow RRLs 100 {pc}, making them some of the physically largest known H II regions in the Galaxy. This survey completes the HRDS H II region census in the Northern sky, where we have discovered 887 H II regions and more than doubled the size of the previously known census of Galactic H II regions.

Extremely Large Magnetoresistance at Low Magnetic Field by Coupling the Nonlinear Transport Effect and the Anomalous Hall Effect.

Science.gov (United States)

Luo, Zhaochu; Xiong, Chengyue; Zhang, Xu; Guo, Zhen-Gang; Cai, Jianwang; Zhang, Xiaozhong

2016-04-13

The anomalous Hall effect of a magnetic material is coupled to the nonlinear transport effect of a semiconductor material in a simple structure to achieve a large geometric magnetoresistance (MR) based on a diode-assisted mechanism. An extremely large MR (>10(4) %) at low magnetic fields (1 mT) is observed at room temperature. This MR device shows potential for use as a logic gate for the four basic Boolean logic operations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Low-mass Stars with Extreme Mid-Infrared Excesses: Potential Signatures of Planetary Collisions

Science.gov (United States)

Theissen, Christopher; West, Andrew

2018-01-01

I investigate the occurrence of extreme mid-infrared (MIR) excesses, a tracer of large amounts of dust orbiting stars, in low-mass stellar systems. Extreme MIR excesses, defined as an excess IR luminosity greater than 1% of the stellar luminosity (LIR/L* ≥ 0.01), have previously only been observed around a small number of solar-mass (M⊙) stars. The origin of this excess has been hypothesized to be massive amounts of orbiting dust, created by collisions between terrestrial planets or large planetesimals. Until recently, there was a dearth of low-mass (M* ≤ 0.6M⊙) stars exhibiting extreme MIR excesses, even though low-mass stars are ubiquitous (~70% of all stars), and known to host multiple terrestrial planets (≥ 3 planets per star).I combine the spectroscopic sample of low-mass stars from the Sloan Digital Sky Survey (SDSS) Data Release 7 (70,841 stars) with MIR photometry from the Wide-field Infrared Survey Explorer (WISE), to locate stars exhibiting extreme MIR excesses. I find the occurrence frequency of low-mass field stars (stars with ages ≥ 1 Gyr) exhibiting extreme MIR excesses is much larger than that for higher-mass field stars (0.41 ± 0.03% versus 0.00067 ± 0.00033%, respectively).In addition, I build a larger sample of low-mass stars based on stellar colors and proper motions using SDSS, WISE, and the Two-Micron All-Sky Survey (8,735,004 stars). I also build a galactic model to simulate stellar counts and kinematics to estimate the number of stars missing from my sample. I perform a larger, more complete study of low-mass stars exhibiting extreme MIR excesses, and find a lower occurrence frequency (0.020 ± 0.001%) than found in the spectroscopic sample but that is still orders of magnitude larger than that for higher-mass stars. I find a slight trend for redder stars (lower-mass stars) to exhibit a higher occurrence frequency of extreme MIR excesses, as well as a lower frequency with increased stellar age. These samples probe important

Morel-Lavallee Lesion in the Upper Extremity.

Science.gov (United States)

Cochran, Grant K; Hanna, Kathryn H

2017-01-01

Background: The Morel-Lavallee lesion (MLL) is a closed internal degloving injury that results from shearing of the skin and subcutaneous tissue from the underlying fascia. Disruption of the perforating blood vessels and lymphatics results in a lesion filled with serosanguinous fluid and necrotized fat. MLLs are most commonly described in association with pelvic and lower extremity trauma, and there are limited reports of these lesions in other locations. Methods: This case report describes a 58-year-old male referred from his primary care physician with a soft tissue mass in the upper arm. Careful history discovered prior trauma with extensive bruising and MRI revealed a large encapsulated mass consistent with MLL. Results: An open debridement with excision of pseudocapsule was performed. Meticulous closure over a drain was performed and the patient healed without complication or recurrence. Intra-operative cultures were negative and pathology was consistent with MLL. Conclusion: MLL should always be considered in the setting of previous trauma regardless the location. In the chronic setting an open approach with excision of pseudocapsule can have an acceptable result.

Investigating NARCCAP Precipitation Extremes via Bivariate Extreme Value Theory (Invited)

Science.gov (United States)

Weller, G. B.; Cooley, D. S.; Sain, S. R.; Bukovsky, M. S.; Mearns, L. O.

2013-12-01

We introduce methodology from statistical extreme value theory to examine the ability of reanalysis-drive regional climate models to simulate past daily precipitation extremes. Going beyond a comparison of summary statistics such as 20-year return values, we study whether the most extreme precipitation events produced by climate model simulations exhibit correspondence to the most extreme events seen in observational records. The extent of this correspondence is formulated via the statistical concept of tail dependence. We examine several case studies of extreme precipitation events simulated by the six models of the North American Regional Climate Change Assessment Program (NARCCAP) driven by NCEP reanalysis. It is found that the NARCCAP models generally reproduce daily winter precipitation extremes along the Pacific coast quite well; in contrast, simulation of past daily summer precipitation extremes in a central US region is poor. Some differences in the strength of extremal correspondence are seen in the central region between models which employ spectral nudging and those which do not. We demonstrate how these techniques may be used to draw a link between extreme precipitation events and large-scale atmospheric drivers, as well as to downscale extreme precipitation simulated by a future run of a regional climate model. Specifically, we examine potential future changes in the nature of extreme precipitation along the Pacific coast produced by the pineapple express (PE) phenomenon. A link between extreme precipitation events and a "PE Index" derived from North Pacific sea-surface pressure fields is found. This link is used to study PE-influenced extreme precipitation produced by a future-scenario climate model run.

Prototype of a laser guide star wavefront sensor for the Extremely Large Telescope

Science.gov (United States)

Patti, M.; Lombini, M.; Schreiber, L.; Bregoli, G.; Arcidiacono, C.; Cosentino, G.; Diolaiti, E.; Foppiani, I.

2018-06-01

The new class of large telescopes, like the future Extremely Large Telescope (ELT), are designed to work with a laser guide star (LGS) tuned to a resonance of atmospheric sodium atoms. This wavefront sensing technique presents complex issues when applied to big telescopes for many reasons, mainly linked to the finite distance of the LGS, the launching angle, tip-tilt indetermination and focus anisoplanatism. The implementation of a laboratory prototype for the LGS wavefront sensor (WFS) at the beginning of the phase study of MAORY (Multi-conjugate Adaptive Optics Relay) for ELT first light has been indispensable in investigating specific mitigation strategies for the LGS WFS issues. This paper presents the test results of the LGS WFS prototype under different working conditions. The accuracy within which the LGS images are generated on the Shack-Hartmann WFS has been cross-checked with the MAORY simulation code. The experiments show the effect of noise on centroiding precision, the impact of LGS image truncation on wavefront sensing accuracy as well as the temporal evolution of the sodium density profile and LGS image under-sampling.

Development of a Large-Format Science-Grade CMOS Active Pixel Sensor, for Extreme Ultra Violet Spectroscopy and Imaging in Space Science

National Research Council Canada - National Science Library

Waltham, N. R; Prydderch, M; Mapson-Menard, H; Morrissey, Q; Turchetta, R; Pool, P; Harris, A

2005-01-01

We describe our programme to develop a large-format science-grade CMOS active pixel sensor for future space science missions, and in particular an extreme ultra-violet spectrograph for solar physics...

Rain Characteristics and Large-Scale Environments of Precipitation Objects with Extreme Rain Volumes from TRMM Observations

Science.gov (United States)

Zhou, Yaping; Lau, William K M.; Liu, Chuntao

2013-01-01

This study adopts a "precipitation object" approach by using 14 years of Tropical Rainfall Measuring Mission (TRMM) Precipitation Feature (PF) and National Centers for Environmental Prediction (NCEP) reanalysis data to study rainfall structure and environmental factors associated with extreme heavy rain events. Characteristics of instantaneous extreme volumetric PFs are examined and compared to those of intermediate and small systems. It is found that instantaneous PFs exhibit a much wider scale range compared to the daily gridded precipitation accumulation range. The top 1% of the rainiest PFs contribute over 55% of total rainfall and have 2 orders of rain volume magnitude greater than those of the median PFs. We find a threshold near the top 10% beyond which the PFs grow exponentially into larger, deeper, and colder rain systems. NCEP reanalyses show that midlevel relative humidity and total precipitable water increase steadily with increasingly larger PFs, along with a rapid increase of 500 hPa upward vertical velocity beyond the top 10%. This provides the necessary moisture convergence to amplify and sustain the extreme events. The rapid increase in vertical motion is associated with the release of convective available potential energy (CAPE) in mature systems, as is evident in the increase in CAPE of PFs up to 10% and the subsequent dropoff. The study illustrates distinct stages in the development of an extreme rainfall event including: (1) a systematic buildup in large-scale temperature and moisture, (2) a rapid change in rain structure, (3) explosive growth of the PF size, and (4) a release of CAPE before the demise of the event.

Statistical Model of Extreme Shear

DEFF Research Database (Denmark)

Larsen, Gunner Chr.; Hansen, Kurt Schaldemose

2004-01-01

In order to continue cost-optimisation of modern large wind turbines, it is important to continously increase the knowledge on wind field parameters relevant to design loads. This paper presents a general statistical model that offers site-specific prediction of the probability density function...... by a model that, on a statistically consistent basis, describe the most likely spatial shape of an extreme wind shear event. Predictions from the model have been compared with results from an extreme value data analysis, based on a large number of high-sampled full-scale time series measurements...... are consistent, given the inevitabel uncertainties associated with model as well as with the extreme value data analysis. Keywords: Statistical model, extreme wind conditions, statistical analysis, turbulence, wind loading, statistical analysis, turbulence, wind loading, wind shear, wind turbines....

Magnetars: Challenging the Extremes of Nature

Science.gov (United States)

Kouveliotou, Chryssa

2011-01-01

Magnetars are magnetically powered rotating neutron stars with extreme magnetic fields (over 10(exp 14) Gauss). They are discovered and emit predominantly in the X- and gamma-rays. Very few sources (roughly 15) have been found since their discovery in 1987. NASA s Fermi Observatory was launched June 11, 2009; the Fermi Gamma Ray Burst Monitor (GBM) began normal operations on July 14, about a month after launch, when the trigger algorithms were enabled. Since then, we recorded emission from four magnetar sources; of these, only one was an old magnetar: SGR 1806+20. The other three detections were two brand new sources, SGR J0501+4516, discovered with Swift and extensively monitored with both Swift and GBM, SGR J0418+5729, discovered with GBM and the Interplanetary Network (IPN), and SGR J1550-5418, a source originally classified as an Anomalous X-ray Pulsar (AXP 1E1547.0-5408). In my talk I will give a short history of the discovery of magnetars and describe how this, once relatively esoteric field, has emerged as a link between several astrophysical areas including Gamma-Ray Bursts. Finally, I will describe the properties of these sources and the current status of our knowledge of the magnetar population and birth rate.

Optimization with Extremal Dynamics

International Nuclear Information System (INIS)

Boettcher, Stefan; Percus, Allon G.

2001-01-01

We explore a new general-purpose heuristic for finding high-quality solutions to hard discrete optimization problems. The method, called extremal optimization, is inspired by self-organized criticality, a concept introduced to describe emergent complexity in physical systems. Extremal optimization successively updates extremely undesirable variables of a single suboptimal solution, assigning them new, random values. Large fluctuations ensue, efficiently exploring many local optima. We use extremal optimization to elucidate the phase transition in the 3-coloring problem, and we provide independent confirmation of previously reported extrapolations for the ground-state energy of ±J spin glasses in d=3 and 4

A New Population of High-z, Dusty Lyman-alpha Emitters and Blobs Discovered by WISE: Feedback Caught in the Act?

Science.gov (United States)

Bridge, Carrie R.; Blain, Andrew; Borys, Colin J. K.; Petty, Sara; Benford, Dominic; Eisenhardt, Peter; Farrah, Duncan; Griffith, Roger, L.; Jarrett, Tom; Lonsdale, Carol;

MRI induced second-degree burn in a patient with extremely large uterine leiomyomas: A case report

International Nuclear Information System (INIS)

Lee, Chul Min; Kang, Bo Kyeong; Song, Soon Young; Koh, Byung Hee; Choi, Joong Sub; Lee, Won Moo

2015-01-01

Burns and thermal injuries related with magnetic resonance imaging (MRI) are rare. Previous literature indicates that medical devices with cable, cosmetics or tattoo are known as risk factors for burns and thermal injuries. However, there is no report of MRI-related burns in Korea. Herein, we reported a case of deep second degree burn after MRI in a 38-year-old female patient with multiple uterine leiomyomas including some that were large and degenerated. The large uterine leiomyoma-induced protruded anterior abdominal wall in direct contact with the body coil during MRI was suspected as the cause of injury, by retrospective analysis. Therefore, awareness of MRI related thermal injury is necessary to prevent this hazard, together with extreme care during MRI

MRI induced second-degree burn in a patient with extremely large uterine leiomyomas: A case report

Energy Technology Data Exchange (ETDEWEB)

Lee, Chul Min; Kang, Bo Kyeong; Song, Soon Young; Koh, Byung Hee; Choi, Joong Sub; Lee, Won Moo [Hanyang University Medical Center, Hanyang University College of Medicine, Seoul (Korea, Republic of)

2015-12-15

Burns and thermal injuries related with magnetic resonance imaging (MRI) are rare. Previous literature indicates that medical devices with cable, cosmetics or tattoo are known as risk factors for burns and thermal injuries. However, there is no report of MRI-related burns in Korea. Herein, we reported a case of deep second degree burn after MRI in a 38-year-old female patient with multiple uterine leiomyomas including some that were large and degenerated. The large uterine leiomyoma-induced protruded anterior abdominal wall in direct contact with the body coil during MRI was suspected as the cause of injury, by retrospective analysis. Therefore, awareness of MRI related thermal injury is necessary to prevent this hazard, together with extreme care during MRI.

Caught in the act: discovering secreted proteins from fungi and oomycetes in action

DEFF Research Database (Denmark)

Roth, Doris; Grell, Morten Nedergaard; Jensen, Annette Bruun

Host-microbe relationships largely rely on secreted proteins like enzymes, virulence factors and antimicrobial peptides. To discover proteins secreted by microbe and host during the interaction with each other, we produced dual-organism cDNA libraries from three different fungus- or oomycete-infe......, by applying a similar strategy with a fungus-only library. As a result, we will show that our approach is widely applicable and allows us to deepen the understanding a variety of different host-microbe systems.......Host-microbe relationships largely rely on secreted proteins like enzymes, virulence factors and antimicrobial peptides. To discover proteins secreted by microbe and host during the interaction with each other, we produced dual-organism cDNA libraries from three different fungus- or oomycete...

THE MOST LUMINOUS GALAXIES DISCOVERED BY WISE

Energy Technology Data Exchange (ETDEWEB)

Tsai, Chao-Wei; Eisenhardt, Peter R. M.; Stern, Daniel; Moustakas, Leonidas A. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States); Wu, Jingwen; Wright, Edward L. [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095-1547 (United States); Assef, Roberto J. [Núcleo de Astronomía de la Facultad deIngeniería, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago (Chile); Blain, Andrew W. [Department of Physics and Astronomy, University of Leicester, 1 University Road, Leicester, LE1 7RH (United Kingdom); Bridge, Carrie R.; Sayers, Jack [Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Benford, Dominic J.; Leisawitz, David T. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Cutri, Roc M.; Masci, Frank J.; Yan, Lin [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Griffith, Roger L. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Jarrett, Thomas H. [Astronomy Department, University of Cape Town, Private Bag X3, Rondebosch 7701 (South Africa); Lonsdale, Carol J. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Petty, Sara M. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Stanford, S. Adam, E-mail: Chao-Wei.Tsai@jpl.nasa.gov [Department of Physics, University of California Davis, One Shields Avenue, Davis, CA 95616 (United States); and others

2015-06-01

We present 20 Wide-field Infrared Survey Explorer (WISE)-selected galaxies with bolometric luminosities L{sub bol} > 10{sup 14} L{sub ☉}, including five with infrared luminosities L{sub IR} ≡ L{sub (rest} {sub 8–1000} {sub μm)} > 10{sup 14} L{sub ☉}. These “extremely luminous infrared galaxies,” or ELIRGs, were discovered using the “W1W2-dropout” selection criteria which requires marginal or non-detections at 3.4 and 4.6 μm (W1 and W2, respectively) but strong detections at 12 and 22 μm in the WISE survey. Their spectral energy distributions are dominated by emission at rest-frame 4–10 μm, suggesting that hot dust with T{sub d} ∼ 450 K is responsible for the high luminosities. These galaxies are likely powered by highly obscured active galactic nuclei (AGNs), and there is no evidence suggesting these systems are beamed or lensed. We compare this WISE-selected sample with 116 optically selected quasars that reach the same L{sub bol} level, corresponding to the most luminous unobscured quasars in the literature. We find that the rest-frame 5.8 and 7.8 μm luminosities of the WISE-selected ELIRGs can be 30%–80% higher than that of the unobscured quasars. The existence of AGNs with L{sub bol} > 10{sup 14} L{sub ☉} at z > 3 suggests that these supermassive black holes are born with large mass, or have very rapid mass assembly. For black hole seed masses ∼10{sup 3} M{sub ☉}, either sustained super-Eddington accretion is needed, or the radiative efficiency must be <15%, implying a black hole with slow spin, possibly due to chaotic accretion.

A decade of weather extremes

NARCIS (Netherlands)

Coumou, Dim; Rahmstorf, Stefan

The ostensibly large number of recent extreme weather events has triggered intensive discussions, both in- and outside the scientific community, on whether they are related to global warming. Here, we review the evidence and argue that for some types of extreme - notably heatwaves, but also

Evaluating the ClimEx Single Model Large Ensemble in Comparison with EURO-CORDEX Results of Seasonal Means and Extreme Precipitation Indicators

Science.gov (United States)

von Trentini, F.; Schmid, F. J.; Braun, M.; Brisette, F.; Frigon, A.; Leduc, M.; Martel, J. L.; Willkofer, F.; Wood, R. R.; Ludwig, R.

2017-12-01

Meteorological extreme events seem to become more frequent in the present and future, and a seperation of natural climate variability and a clear climate change effect on these extreme events gains more and more interest. Since there is only one realisation of historical events, natural variability in terms of very long timeseries for a robust statistical analysis is not possible with observation data. A new single model large ensemble (SMLE), developed for the ClimEx project (Climate change and hydrological extreme events - risks and perspectives for water management in Bavaria and Québec) is supposed to overcome this lack of data by downscaling 50 members of the CanESM2 (RCP 8.5) with the Canadian CRCM5 regional model (using the EURO-CORDEX grid specifications) for timeseries of 1950-2099 each, resulting in 7500 years of simulated climate. This allows for a better probabilistic analysis of rare and extreme events than any preceding dataset. Besides seasonal sums, several extreme indicators like R95pTOT, RX5day and others are calculated for the ClimEx ensemble and several EURO-CORDEX runs. This enables us to investigate the interaction between natural variability (as it appears in the CanESM2-CRCM5 members) and a climate change signal of those members for past, present and future conditions. Adding the EURO-CORDEX results to this, we can also assess the role of internal model variability (or natural variability) in climate change simulations. A first comparison shows similar magnitudes of variability of climate change signals between the ClimEx large ensemble and the CORDEX runs for some indicators, while for most indicators the spread of the SMLE is smaller than the spread of different CORDEX models.

Extreme Temperature Regimes during the Cool Season and their Associated Large-Scale Circulations

Science.gov (United States)

Xie, Z.

2015-12-01

In the cool season (November-March), extreme temperature events (ETEs) always hit the continental United States (US) and provide significant societal impacts. According to the anomalous amplitudes of the surface air temperature (SAT), there are two typical types of ETEs, e.g. cold waves (CWs) and warm waves (WWs). This study used cluster analysis to categorize both CWs and WWs into four distinct regimes respectively and investigated their associated large-scale circulations on intra-seasonal time scale. Most of the CW regimes have large areal impact over the continental US. However, the distribution of cold SAT anomalies varies apparently in four regimes. In the sea level, the four CW regimes are characterized by anomalous high pressure over North America (near and to west of cold anomaly) with different extension and orientation. As a result, anomalous northerlies along east flank of anomalous high pressure convey cold air into the continental US. To the middle troposphere, the leading two groups feature large-scale and zonally-elongated circulation anomaly pattern, while the other two regimes exhibit synoptic wavetrain pattern with meridionally elongated features. As for the WW regimes, there are some patterns symmetry and anti-symmetry with respect to CW regimes. The WW regimes are characterized by anomalous low pressure and southerlies wind over North America. The first and fourth groups are affected by remote forcing emanating from North Pacific, while the others appear mainly locally forced.

When least is best how mathematicians discovered many clever ways to make things as small (or as large) as possible

CERN Document Server

Nahin, Paul J

2003-01-01

What is the best way to photograph a speeding bullet? Why does light move through glass in the least amount of time possible? How can lost hikers find their way out of a forest? What will rainbows look like in the future? Why do soap bubbles have a shape that gives them the least area? By combining the mathematical history of extrema with contemporary examples, Paul J. Nahin answers these intriguing questions and more in this engaging and witty volume. He shows how life often works at the extremes--with values becoming as small (or as large) as possible--and how mathematicians over the centuri

SHIELD: The Star Formation Law in Extremely Low-mass Galaxies

Science.gov (United States)

Teich, Yaron; McNichols, Andrew; Cannon, John M.; SHIELD Team

2016-01-01

The "Survey of HI in Extremely Low-mass Dwarfs" (SHIELD) is a multiwavelength, legacy-class observational study of 12 low-mass dwarf galaxies discovered in Arecibo Legacy Fast ALFA (ALFALFA) survey data products. Here we analyze the relationships between HI and star formation in these systems using multi-configuration, high spatial (~300 pc) and spectral (0.82 - 2.46 km s-1 ch-1) resolution HI observations from the Karl G. Jansky Very Large Array, Hα imaging from the WIYN 3.5m telescope, and archival GALEX far-ultraviolet imaging. We compare the locations and intensities of star formation with the properties of the neutral ISM. We quantify the degree of local co-spatiality between star forming regions and regions of high HI column densities using the Kennicutt-Schmidt (K-S) relation. The values of the K-S index N vary considerably from system to system; because no single galaxy is representative of the sample, we instead focus on the narratives of the individual galaxies and their complex distribution of gaseous and stellar components. At the extremely faint end of the HI mass function, these systems are dominated by stochastic fluctuations in their interstellar media, which governs whether or not they show signs of recent star formation.Support for this work was provided by NSF grant AST-1211683 to JMC at Macalester College.

Modeling, Forecasting and Mitigating Extreme Earthquakes

Science.gov (United States)

Ismail-Zadeh, A.; Le Mouel, J.; Soloviev, A.

2012-12-01

Recent earthquake disasters highlighted the importance of multi- and trans-disciplinary studies of earthquake risk. A major component of earthquake disaster risk analysis is hazards research, which should cover not only a traditional assessment of ground shaking, but also studies of geodetic, paleoseismic, geomagnetic, hydrological, deep drilling and other geophysical and geological observations together with comprehensive modeling of earthquakes and forecasting extreme events. Extreme earthquakes (large magnitude and rare events) are manifestations of complex behavior of the lithosphere structured as a hierarchical system of blocks of different sizes. Understanding of physics and dynamics of the extreme events comes from observations, measurements and modeling. A quantitative approach to simulate earthquakes in models of fault dynamics will be presented. The models reproduce basic features of the observed seismicity (e.g., the frequency-magnitude relationship, clustering of earthquakes, occurrence of extreme seismic events). They provide a link between geodynamic processes and seismicity, allow studying extreme events, influence of fault network properties on seismic patterns and seismic cycles, and assist, in a broader sense, in earthquake forecast modeling. Some aspects of predictability of large earthquakes (how well can large earthquakes be predicted today?) will be also discussed along with possibilities in mitigation of earthquake disasters (e.g., on 'inverse' forensic investigations of earthquake disasters).

On the evolutionary status and pulsations of the recently discovered blue large-amplitude pulsators (BLAPs)

Science.gov (United States)

Romero, Alejandra D.; Córsico, A. H.; Althaus, L. G.; Pelisoli, I.; Kepler, S. O.

2018-06-01

The blue large-amplitude pulsators (BLAPs) constitute a new class of pulsating stars. They are hot stars with effective temperatures of ˜30 000 K and surface gravities of log g ˜ 4.9, that pulsate with periods in the range 20-40 min. Until now, their origin and evolutionary state, as well as the nature of their pulsations, were not been unveiled. In this paper, we propose that the BLAPs are the hot counterpart of the already known pulsating pre-extremely low mass (pre-ELM) white dwarf (WD) stars, that are He-core low-mass stars resulting from interacting binary evolution. Using fully evolutionary sequences, we show that the BLAPs are well represented by pre-ELM WD models with high effective temperature and stellar masses ˜0.34 M⊙. From the analysis of their pulsational properties, we find that the observed variabilities can be explained by high-order non-radial g-mode pulsations or, in the case of the shortest periods, also by low-order radial modes, including the fundamental radial mode. The theoretical modes with periods in the observed range are unstable due to the κ mechanism associated with the Z-bump in the opacity at log T ˜ 5.25.

Statistical Model of Extreme Shear

DEFF Research Database (Denmark)

Hansen, Kurt Schaldemose; Larsen, Gunner Chr.

2005-01-01

In order to continue cost-optimisation of modern large wind turbines, it is important to continuously increase the knowledge of wind field parameters relevant to design loads. This paper presents a general statistical model that offers site-specific prediction of the probability density function...... by a model that, on a statistically consistent basis, describes the most likely spatial shape of an extreme wind shear event. Predictions from the model have been compared with results from an extreme value data analysis, based on a large number of full-scale measurements recorded with a high sampling rate...

Discovering Hands - México

OpenAIRE

Salamanca Cárdenas, Daniela; Castelblanco Domínguez, Junio Andrés; Aguilar Ardila, Laura Andrea

2016-01-01

El modelo de Discovering Hands ha sido reconocido internacionalmente como un proyecto innovador que se ha expandido por diferentes países del mundo, como Austria, y se ha empezado a estudiar la propuesta en países como República Checa, India y Colombia. (Discovering Hands, 2016). Esto se debe a que no solo mejora el tratamiento de cáncer de mama, sino que también reduce los costos totales de tratamiento de la enfermedad y aumenta la fuerza laborar de los países donde esté presente. Al represe...

Extreme-value dependence: An application to exchange rate markets

Science.gov (United States)

Fernandez, Viviana

2007-04-01

Extreme value theory (EVT) focuses on modeling the tail behavior of a loss distribution using only extreme values rather than the whole data set. For a sample of 10 countries with dirty/free float regimes, we investigate whether paired currencies exhibit a pattern of asymptotic dependence. That is, whether an extremely large appreciation or depreciation in the nominal exchange rate of one country might transmit to another. In general, after controlling for volatility clustering and inertia in returns, we do not find evidence of extreme-value dependence between paired exchange rates. However, for asymptotic-independent paired returns, we find that tail dependency of exchange rates is stronger under large appreciations than under large depreciations.

Large Extremity Peripheral Nerve Repair

Science.gov (United States)

2016-12-01

These antimicrobial peptides are implicated in the resistance of epithelial surfaces to microbial colonisation and have been shown to be upregulated...be equivalent to standard autograft repair in rodent models. Outcomes have now been validated in a large animal (swine) model with 5 cm ulnar nerve...Goals of the Project Task 1– Determine mechanical properties, seal strength and resistance to biodegradation of candidate photochemical nerve wrap

Superior radiation-resistant nanoengineered austenitic 304L stainless steel for applications in extreme radiation environments.

Science.gov (United States)

Sun, C; Zheng, S; Wei, C C; Wu, Y; Shao, L; Yang, Y; Hartwig, K T; Maloy, S A; Zinkle, S J; Allen, T R; Wang, H; Zhang, X

2015-01-15

Nuclear energy provides more than 10% of electrical power internationally, and the increasing engagement of nuclear energy is essential to meet the rapid worldwide increase in energy demand. A paramount challenge in the development of advanced nuclear reactors is the discovery of advanced structural materials that can endure extreme environments, such as severe neutron irradiation damage at high temperatures. It has been known for decades that high dose radiation can introduce significant void swelling accompanied by precipitation in austenitic stainless steel (SS). Here we report, however, that through nanoengineering, ultra-fine grained (UFG) 304 L SS with an average grain size of ~100 nm, can withstand Fe ion irradiation at 500 °C to 80 displacements-per-atom (dpa) with moderate grain coarsening. Compared to coarse grained (CG) counterparts, swelling resistance of UFG SS is improved by nearly an order of magnitude and swelling rate is reduced by a factor of 5. M(23)C(6) precipitates, abundant in irradiated CG SS, are largely absent in UFG SS. This study provides a nanoengineering approach to design and discover radiation tolerant metallic materials for applications in extreme radiation environments.

Prospecting direction and favourable target areas for exploration of large and super-large uranium deposits in China

International Nuclear Information System (INIS)

Liu Xingzhong

1993-01-01

A host of large uranium deposits have been successively discovered abroad by means of geological exploration, metallogenetic model studies and the application of new geophysical and geochemical methods since 1970's. Thorough undertaking geological research relevant to prospecting for super large uranium deposits have attracted great attention of the worldwide geological circle. The important task for the vast numbers of uranium geological workers is to make an afford to discover more numerous large and super large uranium deposits in China. The author comprehensively analyses the regional geological setting and geological metallogenetic conditions for the super large uranium deposits in the world. Comparative studies have been undertaken and the prospecting direction and favourable target areas for the exploration of super large uranium deposits in China have been proposed

Changes in daily climate extremes in China and their connection to the large scale atmospheric circulation during 1961-2003

Energy Technology Data Exchange (ETDEWEB)

You, Qinglong [Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Laboratory of Tibetan Environment Changes and Land Surface Processes, Beijing (China); Friedrich-Schiller University Jena, Department of Geoinformatics, Jena (Germany); Graduate University of Chinese Academy of Sciences, Beijing (China); Kang, Shichang [Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Laboratory of Tibetan Environment Changes and Land Surface Processes, Beijing (China); State Key Laboratory of Cryospheric Science, Chinese Academy of Sciences, Lanzhou (China); Aguilar, Enric [Universitat Rovirai Virgili de Tarragona, Climate Change Research Group, Geography Unit, Tarragona (Spain); Pepin, Nick [University of Portsmouth, Department of Geography, Portsmouth (United Kingdom); Fluegel, Wolfgang-Albert [Friedrich-Schiller University Jena, Department of Geoinformatics, Jena (Germany); Yan, Yuping [National Climate Center, Beijing (China); Xu, Yanwei; Huang, Jie [Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Laboratory of Tibetan Environment Changes and Land Surface Processes, Beijing (China); Graduate University of Chinese Academy of Sciences, Beijing (China); Zhang, Yongjun [Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Laboratory of Tibetan Environment Changes and Land Surface Processes, Beijing (China)

2011-06-15

negative magnitudes. This is inconsistent with changes of water vapor flux calculated from NCEP/NCAR reanalysis. Large scale atmospheric circulation changes derived from NCEP/NCAR reanalysis grids show that a strengthening anticyclonic circulation, increasing geopotential height and rapid warming over the Eurasian continent have contributed to the changes in climate extremes in China. (orig.)

Decision Tree Approach to Discovering Fraud in Leasing Agreements

OpenAIRE

Horvat Ivan; Pejić Bach Mirjana; Merkač Skok Marjana

2014-01-01

Background: Fraud attempts create large losses for financing subjects in modern economies. At the same time, leasing agreements have become more and more popular as a means of financing objects such as machinery and vehicles, but are more vulnerable to fraud attempts. Objectives: The goal of the paper is to estimate the usability of the data mining approach in discovering fraud in leasing agreements. Methods/Approach: Real-world data from one Croatian leasing firm was used for creating tow mo...

Did the ancient egyptians discover Algol?

Science.gov (United States)

Jetsu, L.; Porceddu, S.; Porceddu, S.; Lyytinen, J.; Kajatkari, P.; Markkanen, T.; Toivari-Viitala, J.

2013-02-01

Fabritius discovered the first variable star, Mira, in 1596. Holwarda determined the 11 months period of Mira in 1638. Montanari discovered the next variable star, Algol, in 1669. Its period, 2.867 days, was determined by Goodricke (178). Algol was associated with demon-like creatures, "Gorgon" in ancient Greek and "ghoul" in ancient Arab mythology. This indicates that its variability was discovered much before 1669 (Wilk 1996), but this mythological evidence is ambiguous (Davis 1975). For thousands of years, the Ancient Egyptian Scribes (AES) observed stars for timekeeping in a region, where there are nearly 300 clear nights a year. We discovered a significant periodicity of 2.850 days in their calendar for lucky and unlucky days dated to 1224 BC, "the Cairo Calendar". Several astrophysical and astronomical tests supported our conclusion that this was the period of Algol three millennia ago. The "ghoulish habits" of Algol could explain this 0.017 days period increase (Battersby 2012).

Large Scale Influences on Summertime Extreme Precipitation in the Northeastern United States

Science.gov (United States)

Collow, Allison B. Marquardt; Bosilovich, Michael G.; Koster, Randal Dean

2016-01-01

Observations indicate that over the last few decades there has been a statistically significant increase in precipitation in the northeastern United States and that this can be attributed to an increase in precipitation associated with extreme precipitation events. Here a state-of-the-art atmospheric reanalysis is used to examine such events in detail. Daily extreme precipitation events defined at the 75th and 95th percentile from gridded gauge observations are identified for a selected region within the Northeast. Atmospheric variables from the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), are then composited during these events to illustrate the time evolution of associated synoptic structures, with a focus on vertically integrated water vapor fluxes, sea level pressure, and 500-hectopascal heights. Anomalies of these fields move into the region from the northwest, with stronger anomalies present in the 95th percentile case. Although previous studies show tropical cyclones are responsible for the most intense extreme precipitation events, only 10 percent of the events in this study are caused by tropical cyclones. On the other hand, extreme events resulting from cutoff low pressure systems have increased. The time period of the study was divided in half to determine how the mean composite has changed over time. An arc of lower sea level pressure along the East Coast and a change in the vertical profile of equivalent potential temperature suggest a possible increase in the frequency or intensity of synoptic-scale baroclinic disturbances.

Systematic Serendipity: A Method to Discover the Anomalous

Science.gov (United States)

Giles, Daniel; Walkowicz, Lucianne

2018-01-01

One of the challenges in the era of big data astronomical surveys is identifying anomalous data, data that exhibits as-of-yet unobserved behavior. These data may result from systematic errors, extreme (or rare) forms of known phenomena, or, most interestingly, truly novel phenomena that has historically required a trained eye and often fortuitous circumstance to identify. We describe a method that uses machine clustering techniques to discover anomalous data in Kepler lightcurves, as a step towards systematizing the detection of novel phenomena in the era of LSST. As a proof of concept, we apply our anomaly detection method to Kepler data including Boyajian's Star (KIC 8462852). We examine quarters 4, 8, 11, and 16 of the Kepler data which contain Boyajian’s Star acting normally (quarters 4 and 11) and anomalously (quarters 8 and 16). We demonstrate that our method is capable of identifying Boyajian’s Star’s anomalous behavior in quarters of interest, and we further identify other anomalous light curves that exhibit a range of interesting variability.

D Webgis and Visualization Issues for Architectures and Large Sites

Science.gov (United States)

De Amicis, R.; Conti, G.; Girardi, G.; Andreolli, M.

2011-09-01

Traditionally, within the field of archaeology and, more generally, within the cultural heritage domain, Geographical Information Systems (GIS) have been mostly used as support to cataloguing activities, essentially operating as gateways to large geo-referenced archives of specialised cultural heritage information. Additionally GIS have proved to be essential to help cultural heritage institutions improve management of their historical information, providing the means for detection of otherwise hard-to-discover spatial patterns, supporting with computation tools necessary to perform spatial clustering, proximity and orientation analysis. This paper presents a platform developed to answer to both the aforementioned issues, by allowing geo-referenced cataloguing of multi-media resources of cultural relevance as well as access, in a user-friendly manner, through an interactive 3D geobrowser which operates as single point of access to the available digital repositories. The solution has been showcased in the context of "Festival dell'economia" (the Fair of Economics) a major event recently occurred in Trento, Italy and it has allowed visitors of the event to interactively access an extremely large repository of information, as well as their metadata, available across the area of the Autonomous Province of Trento, in Italy. Within the event, an extremely large repository was made accessible, via the network, through web-services, from a 3D interactive geobrowser developed by the authors. The 3D scene was enriched with a number of Points of Interest (POIs) linking to information available within various databases. The software package was deployed with a complex hardware set-up composed of a large composite panoramic screen covering a horizontal field of view of 240 degrees.

Legacies from extreme drought increase ecosystem sensitivity to future extremes

Science.gov (United States)

Smith, M. D.; Knapp, A.; Hoover, D. L.; Avolio, M. L.; Felton, A. J.; Wilcox, K. R.

2016-12-01

Climate extremes, such as drought, are increasing in frequency and intensity, and the ecological consequences of these extreme events can be substantial and widespread. Although there is still much to be learned about how ecosystems will respond to an intensification of drought, even less is known about the factors that determine post-drought recovery of ecosystem function. Such knowledge is particularly important because post-drought recovery periods can be protracted depending on the extent to which key plant populations, community structure and biogeochemical processes are affected. These drought legacies may alter ecosystem function for many years post-drought and may impact future sensitivity to climate extremes. We experimentally imposed two extreme growing season droughts in a central US grassland to assess the impacts of repeated droughts on ecosystem resistance (response) and resilience (recovery). We found that this grassland was not resistant to the first extreme drought due to reduced productivity and differential sensitivity of the co-dominant C4 grass (Andropogon gerardii) and C3 forb (Solidago canadensis) species. This differential sensitivity led to a reordering of species abundances within the plant community. Yet, despite this large shift in plant community composition, which persisted post-drought, the grassland was highly resilient post-drought, due to increased abundance of the dominant C4 grass. Because of this shift to increased C4 grass dominance, we expected that previously-droughted grassland would be more resistant to a second extreme drought. However, contrary to these expectations, previously droughted grassland was more sensitive to drought than grassland that had not experienced drought. Thus, our result suggest that legacies of drought (shift in community composition) may increase ecosystem sensitivity to future extreme events.

Discovering the Solar System

Science.gov (United States)

Jones, Barrie W.

1999-04-01

Discovering the Solar System Barrie W. Jones The Open University, Milton Keynes, UK Discovering the Solar System is a comprehensive, up-to-date account of the Solar System and of the ways in which the various bodies have been investigated and modelled. The approach is thematic, with sequences of chapters on the interiors of planetary bodies, on their surfaces, and on their atmospheres. Within each sequence there is a chapter on general principles and processes followed by one or two chapters on specific bodies. There is also an introductory chapter, a chapter on the origin of the Solar System, and a chapter on asteroids, comets and meteorites. Liberally illustrated with diagrams, black and white photographs and colour plates, Discovering the Solar System also features: * tables of essential data * question and answers within the text * end of section review questions with answers and comments Discovering the Solar System is essential reading for all undergraduate students for whom astronomy or planetary science are components of their degrees, and for those at a more advanced level approaching the subject for the first time. It will also be of great interest to non-specialists with a keen interest in astronomy. A small amount of scientific knowledge is assumed plus familiarity with basic algebra and graphs. There is no calculus. Praise for this book includes: ".certainly qualifies as an authoritative text. The author clearly has an encyclopedic knowledge of the subject." Meteorics and Planetary Science ".liberally doused with relevant graphs, tables, and black and white figures of good quality." EOS, Transactions of the American Geophysical Union ".one of the best books on the Solar System I have seen. The general accuracy and quality of the content is excellent." Journal of the British Astronomical Association

Pancreatic sarcoidosis discovered during Whipple procedure.

Science.gov (United States)

Cook, Jonathan; Spees, Tanner; Telefus, Phillip; Ranaudo, Jeffrey M; Carryl, Stephen; Xiao, Philip

2013-04-04

Pancreatic sarcoidosis is a rare variant of systemic sarcoidosis, with cases described in literature as recently as January 2010. We present here a case of pancreatic involvement with non-caseating granulomas discovered on laparotomy in a patient with a preoperative diagnosis of pancreatic carcinoma. Computer tomography scan without contrast revealed a well-marginated smooth-shaped tumor in the head of the pancreas morphologically consistent with malignancy. During Whipple procedure, the mass was found to be a large lymph node that contained numerous non-caseating granulomas. Radiologically and clinically, non-caseating granulomas of the pancreas are often misdiagnosed as malignant tumor. Special attention given to this differential diagnosis by surgeons, pathologists and clinicians can avoid misdiagnosis and unnecessary treatment. Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author 2013.

Influence of a Large Pillar on the Optimum Roadway Position in an Extremely Close Coal Seam

Directory of Open Access Journals (Sweden)

Li Yang

2016-01-01

Full Text Available Based on the mining practice in an extremely close coal seam, theoretical analysis was conducted on the vertical stress distribution of the floor strata under a large coal pillar. The vertical stress distribution regulation of a No. 5 coal seam was revealed. To obtain the optimum position of the roadway that bears the supporting pressure of a large coal pillar, numerical modeling was applied to analyze the relation among the stress distribution of the roadway surrounding the rock that bears the supporting pressure of a large coal pillar, the plastic zone distribution of the roadway surrounding the rock, the surrounding rock deformation, and the roadway layout position. The theoretical calculation results of the stress value, stress variation rate, and influencing range of the stress influencing angle showed that the reasonable malposition of the No. 5 coal seam roadway was an inner malposition of 4 m. The mining practice showed the following: the layout of No. 25301 panel belt roadway at the position of the inner malposition of 4 m was reasonable, the roadway support performance was favourable without deformation, and ground pressure was not obvious. The research achievement of this study is the provision of a reference for roadway layouts under similar conditions.

A Unique Sample of Extreme-BCG Clusters at 0.2 < z < 0.5

Science.gov (United States)

Garmire, Gordon

2017-09-01

The recently-discovered Phoenix cluster harbors the most extreme BCG in the known universe. Despite the cluster's high mass and X-ray luminosity, it was consistently identified by surveys as an isolated AGN, due to the bright central point source and the compact cool core. Armed with hindsight, we have undertaken an all-sky survey based on archival X-ray, OIR, and radio data to identify other similarly-extreme systems that were likewise missed. A pilot study demonstrated that this strategy works, leading to the discovery of a new, massive cluster at z 0.2 which was missed by previous X-ray surveys due to the presence of a bright central QSO. We propose here to observe 6 new clusters from our complete northern-sky survey, which harbor some of the most extreme central galaxies known.

A Fast SVD-Hidden-nodes based Extreme Learning Machine for Large-Scale Data Analytics.

Science.gov (United States)

Deng, Wan-Yu; Bai, Zuo; Huang, Guang-Bin; Zheng, Qing-Hua

2016-05-01

Big dimensional data is a growing trend that is emerging in many real world contexts, extending from web mining, gene expression analysis, protein-protein interaction to high-frequency financial data. Nowadays, there is a growing consensus that the increasing dimensionality poses impeding effects on the performances of classifiers, which is termed as the "peaking phenomenon" in the field of machine intelligence. To address the issue, dimensionality reduction is commonly employed as a preprocessing step on the Big dimensional data before building the classifiers. In this paper, we propose an Extreme Learning Machine (ELM) approach for large-scale data analytic. In contrast to existing approaches, we embed hidden nodes that are designed using singular value decomposition (SVD) into the classical ELM. These SVD nodes in the hidden layer are shown to capture the underlying characteristics of the Big dimensional data well, exhibiting excellent generalization performances. The drawback of using SVD on the entire dataset, however, is the high computational complexity involved. To address this, a fast divide and conquer approximation scheme is introduced to maintain computational tractability on high volume data. The resultant algorithm proposed is labeled here as Fast Singular Value Decomposition-Hidden-nodes based Extreme Learning Machine or FSVD-H-ELM in short. In FSVD-H-ELM, instead of identifying the SVD hidden nodes directly from the entire dataset, SVD hidden nodes are derived from multiple random subsets of data sampled from the original dataset. Comprehensive experiments and comparisons are conducted to assess the FSVD-H-ELM against other state-of-the-art algorithms. The results obtained demonstrated the superior generalization performance and efficiency of the FSVD-H-ELM. Copyright © 2016 Elsevier Ltd. All rights reserved.

Extremely large nonsaturating magnetoresistance and ultrahigh mobility due to topological surface states in the metallic Bi2Te3 topological insulator

Science.gov (United States)

Shrestha, K.; Chou, M.; Graf, D.; Yang, H. D.; Lorenz, B.; Chu, C. W.

2017-05-01

Weak antilocalization (WAL) effects in Bi2Te3 single crystals have been investigated at high and low bulk charge-carrier concentrations. At low charge-carrier density the WAL curves scale with the normal component of the magnetic field, demonstrating the dominance of topological surface states in magnetoconductivity. At high charge-carrier density the WAL curves scale with neither the applied field nor its normal component, implying a mixture of bulk and surface conduction. WAL due to topological surface states shows no dependence on the nature (electrons or holes) of the bulk charge carriers. The observations of an extremely large nonsaturating magnetoresistance and ultrahigh mobility in the samples with lower carrier density further support the presence of surface states. The physical parameters characterizing the WAL effects are calculated using the Hikami-Larkin-Nagaoka formula. At high charge-carrier concentrations, there is a greater number of conduction channels and a decrease in the phase coherence length compared to low charge-carrier concentrations. The extremely large magnetoresistance and high mobility of topological insulators have great technological value and can be exploited in magnetoelectric sensors and memory devices.

An Efficient Pipeline Wavefront Phase Recovery for the CAFADIS Camera for Extremely Large Telescopes

Directory of Open Access Journals (Sweden)

Eduardo Magdaleno

2009-12-01

Full Text Available In this paper we show a fast, specialized hardware implementation of the wavefront phase recovery algorithm using the CAFADIS camera. The CAFADIS camera is a new plenoptic sensor patented by the Universidad de La Laguna (Canary Islands, Spain: international patent PCT/ES2007/000046 (WIPO publication number WO/2007/082975. It can simultaneously measure the wavefront phase and the distance to the light source in a real-time process. The pipeline algorithm is implemented using Field Programmable Gate Arrays (FPGA. These devices present architecture capable of handling the sensor output stream using a massively parallel approach and they are efficient enough to resolve several Adaptive Optics (AO problems in Extremely Large Telescopes (ELTs in terms of processing time requirements. The FPGA implementation of the wavefront phase recovery algorithm using the CAFADIS camera is based on the very fast computation of two dimensional fast Fourier Transforms (FFTs. Thus we have carried out a comparison between our very novel FPGA 2D-FFTa and other implementations.

Discovering Sentinel Rules for Business Intelligence

Science.gov (United States)

Middelfart, Morten; Pedersen, Torben Bach

This paper proposes the concept of sentinel rules for multi-dimensional data that warns users when measure data concerning the external environment changes. For instance, a surge in negative blogging about a company could trigger a sentinel rule warning that revenue will decrease within two months, so a new course of action can be taken. Hereby, we expand the window of opportunity for organizations and facilitate successful navigation even though the world behaves chaotically. Since sentinel rules are at the schema level as opposed to the data level, and operate on data changes as opposed to absolute data values, we are able to discover strong and useful sentinel rules that would otherwise be hidden when using sequential pattern mining or correlation techniques. We present a method for sentinel rule discovery and an implementation of this method that scales linearly on large data volumes.

An ensemble heterogeneous classification methodology for discovering health-related knowledge in social media messages.

Science.gov (United States)

Tuarob, Suppawong; Tucker, Conrad S; Salathe, Marcel; Ram, Nilam

2014-06-01

The role of social media as a source of timely and massive information has become more apparent since the era of Web 2.0.Multiple studies illustrated the use of information in social media to discover biomedical and health-related knowledge.Most methods proposed in the literature employ traditional document classification techniques that represent a document as a bag of words.These techniques work well when documents are rich in text and conform to standard English; however, they are not optimal for social media data where sparsity and noise are norms.This paper aims to address the limitations posed by the traditional bag-of-word based methods and propose to use heterogeneous features in combination with ensemble machine learning techniques to discover health-related information, which could prove to be useful to multiple biomedical applications, especially those needing to discover health-related knowledge in large scale social media data.Furthermore, the proposed methodology could be generalized to discover different types of information in various kinds of textual data. Social media data is characterized by an abundance of short social-oriented messages that do not conform to standard languages, both grammatically and syntactically.The problem of discovering health-related knowledge in social media data streams is then transformed into a text classification problem, where a text is identified as positive if it is health-related and negative otherwise.We first identify the limitations of the traditional methods which train machines with N-gram word features, then propose to overcome such limitations by utilizing the collaboration of machine learning based classifiers, each of which is trained to learn a semantically different aspect of the data.The parameter analysis for tuning each classifier is also reported. Three data sets are used in this research.The first data set comprises of approximately 5000 hand-labeled tweets, and is used for cross validation of the

Discovering workflow nets using integer linear programming

NARCIS (Netherlands)

van Zelst, S.J.; van Dongen, B.F.; van der Aalst, W.M.P.; Verbeek, H.M.W.

Process mining is concerned with the analysis, understanding and improvement of business processes. Process discovery, i.e. discovering a process model based on an event log, is considered the most challenging process mining task. State-of-the-art process discovery algorithms only discover local

Discovering Diabetes Complications: an Ontology Based Model.

Science.gov (United States)

Daghistani, Tahani; Shammari, Riyad Al; Razzak, Muhammad Imran

2015-12-01

Diabetes is a serious disease that spread in the world dramatically. The diabetes patient has an average of risk to experience complications. Take advantage of recorded information to build ontology as information technology solution will help to predict patients who have average of risk level with certain complication. It is helpful to search and present patient's history regarding different risk factors. Discovering diabetes complications could be useful to prevent or delay the complications. We designed ontology based model, using adult diabetes patients' data, to discover the rules of diabetes with its complications in disease to disease relationship. Various rules between different risk factors of diabetes Patients and certain complications generated. Furthermore, new complications (diseases) might be discovered as new finding of this study, discovering diabetes complications could be useful to prevent or delay the complications. The system can identify the patients who are suffering from certain risk factors such as high body mass index (obesity) and starting controlling and maintaining plan.

Climate impacts on extreme energy consumption of different types of buildings.

Science.gov (United States)

Li, Mingcai; Shi, Jun; Guo, Jun; Cao, Jingfu; Niu, Jide; Xiong, Mingming

2015-01-01

Exploring changes of building energy consumption and its relationships with climate can provide basis for energy-saving and carbon emission reduction. Heating and cooling energy consumption of different types of buildings during 1981-2010 in Tianjin city, was simulated by using TRNSYS software. Daily or hourly extreme energy consumption was determined by percentile methods, and the climate impact on extreme energy consumption was analyzed. The results showed that days of extreme heating consumption showed apparent decrease during the recent 30 years for residential and large venue buildings, whereas days of extreme cooling consumption increased in large venue building. No significant variations were found for the days of extreme energy consumption for commercial building, although a decreasing trend in extreme heating energy consumption. Daily extreme energy consumption for large venue building had no relationship with climate parameters, whereas extreme energy consumption for commercial and residential buildings was related to various climate parameters. Further multiple regression analysis suggested heating energy consumption for commercial building was affected by maximum temperature, dry bulb temperature, solar radiation and minimum temperature, which together can explain 71.5 % of the variation of the daily extreme heating energy consumption. The daily extreme cooling energy consumption for commercial building was only related to the wet bulb temperature (R2= 0.382). The daily extreme heating energy consumption for residential building was affected by 4 climate parameters, but the dry bulb temperature had the main impact. The impacts of climate on hourly extreme heating energy consumption has a 1-3 hour delay in all three types of buildings, but no delay was found in the impacts of climate on hourly extreme cooling energy consumption for the selected buildings.

Early studies reported extreme findings with large variability: a meta-epidemiologic study in the field of endocrinology.

Science.gov (United States)

Wang, Zhen; Alahdab, Fares; Almasri, Jehad; Haydour, Qusay; Mohammed, Khaled; Abu Dabrh, Abd Moain; Prokop, Larry J; Alfarkh, Wedad; Lakis, Sumaya; Montori, Victor M; Murad, Mohammad Hassan

2016-04-01

To evaluate the presence of extreme findings and fluctuation in effect size in endocrinology. We systematically identified all meta-analyses published in 2014 in the field of endocrinology. Within each meta-analysis, the effect size of the primary binary outcome was compared across studies according to their order of publication. We pooled studies using the DerSimonian and Laird random-effects method. Heterogeneity was evaluated using the I(2) and tau(2). Twelve percent of the included 100 meta-analyses reported the largest effect size in the very first published study. The largest effect size occurred in the first 2 earliest studies in 31% of meta-analyses. When the effect size was the largest in the first published study, it was three times larger than the final pooled effect (ratio of rates, 3.26; 95% confidence interval: 1.80, 5.90). The largest heterogeneity measured by I(2) was observed in 18% of the included meta-analyses when combining the first 2 studies or 17% when combing the first 3 studies. In endocrinology, early studies reported extreme findings with large variability. This behavior of the evidence needs to be taken into account when used to formulate clinical policies. Copyright © 2016 Elsevier Inc. All rights reserved.

Polygenic determinants in extremes of high-density lipoprotein cholesterol.

Science.gov (United States)

Dron, Jacqueline S; Wang, Jian; Low-Kam, Cécile; Khetarpal, Sumeet A; Robinson, John F; McIntyre, Adam D; Ban, Matthew R; Cao, Henian; Rhainds, David; Dubé, Marie-Pierre; Rader, Daniel J; Lettre, Guillaume; Tardif, Jean-Claude; Hegele, Robert A

2017-11-01

HDL cholesterol (HDL-C) remains a superior biochemical predictor of CVD risk, but its genetic basis is incompletely defined. In patients with extreme HDL-C concentrations, we concurrently evaluated the contributions of multiple large- and small-effect genetic variants. In a discovery cohort of 255 unrelated lipid clinic patients with extreme HDL-C levels, we used a targeted next-generation sequencing panel to evaluate rare variants in known HDL metabolism genes, simultaneously with common variants bundled into a polygenic trait score. Two additional cohorts were used for validation and included 1,746 individuals from the Montréal Heart Institute Biobank and 1,048 individuals from the University of Pennsylvania. Findings were consistent between cohorts: we found rare heterozygous large-effect variants in 18.7% and 10.9% of low- and high-HDL-C patients, respectively. We also found common variant accumulation, indicated by extreme polygenic trait scores, in an additional 12.8% and 19.3% of overall cases of low- and high-HDL-C extremes, respectively. Thus, the genetic basis of extreme HDL-C concentrations encountered clinically is frequently polygenic, with contributions from both rare large-effect and common small-effect variants. Multiple types of genetic variants should be considered as contributing factors in patients with extreme dyslipidemia. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

Extreme hydrometeorological events in the Peruvian Central Andes during austral summer and their relationship with the large-scale circulation

Science.gov (United States)

Sulca, Juan C.

In this Master's dissertation, atmospheric circulation patterns associated with extreme hydrometeorological events in the Mantaro Basin, Peruvian Central Andes, and their teleconnections during the austral summer (December-January-February-March) are addressed. Extreme rainfall events in the Mantaro basin are related to variations of the large-scale circulation as indicated by the changing strength of the Bolivian High-Nordeste Low (BH-NL) system. Dry (wet) spells are associated with a weakening (strengthening) of the BH-NL system and reduced (enhanced) influx of moist air from the lowlands to the east due to strengthened westerly (easterly) wind anomalies at mid- and upper-tropospheric levels. At the same time extreme rainfall events of the opposite sign occur over northeastern Brazil (NEB) due to enhanced (inhibited) convective activity in conjunction with a strengthened (weakened) Nordeste Low. Cold episodes in the Mantaro Basin are grouped in three types: weak, strong and extraordinary cold episodes. Weak and strong cold episodes in the MB are mainly associated with a weakening of the BH-NL system due to tropical-extratropical interactions. Both types of cold episodes are associated with westerly wind anomalies at mid- and upper-tropospheric levels aloft the Peruvian Central Andes, which inhibit the influx of humid air masses from the lowlands to the east and hence limit the potential for development of convective cloud cover. The resulting clear sky conditions cause nighttime temperatures to drop, leading to cold extremes below the 10-percentile. Extraordinary cold episodes in the MB are associated with cold and dry polar air advection at all tropospheric levels toward the central Peruvian Andes. Therefore, weak and strong cold episodes in the MB appear to be caused by radiative cooling associated with reduced cloudiness, rather than cold air advection, while the latter plays an important role for extraordinary cold episodes only.

Discovering Wavelets

CERN Document Server

Aboufadel, Edward

1999-01-01

An accessible and practical introduction to wavelets. With applications in image processing, audio restoration, seismology, and elsewhere, wavelets have been the subject of growing excitement and interest over the past several years. Unfortunately, most books on wavelets are accessible primarily to research mathematicians. Discovering Wavelets presents basic and advanced concepts of wavelets in a way that is accessible to anyone with only a fundamental knowledge of linear algebra. The basic concepts of wavelet theory are introduced in the context of an explanation of how the FBI uses wavelets

Analysis of farmers’ adaptation to weather extremes in West African Sudan Savanna

Directory of Open Access Journals (Sweden)

David Boansi

2017-06-01

Full Text Available There have been recent incidences of weather extremes in the West African Sudan Savanna and farmers have responded through implementation of relevant adaptation strategies. For a deeper insight into farmers’ adaptation to climatic shocks, this study documents farmers’ perception of recent changes in the local climate, and identifies factors that influence the number and choice of strategies implemented. Interdependencies among strategies are explored and joint and marginal probabilities of adoption estimated. Upper East Ghana and Southwest Burkina Faso are used as the case study regions. These regions were selected due to extreme reliance of inhabitants on agriculture for sustenance, and their recent exposure to weather extremes. Through estimation of a Poisson regression and multivariate probit model to identify the major factors that influence the number and choice of strategies adopted, we discover that, limited access to credit, markets, and extension services, smaller cropland area, and low level of mechanization could impede effective adaptation to weather extremes. To enhance farmers’ adaptive capacity, policy makers and various stakeholders need to contribute towards improving farmers’ access to credit, markets, and extension services, and implement measures to promote mechanization.

Climate impacts on extreme energy consumption of different types of buildings.

Directory of Open Access Journals (Sweden)

Mingcai Li

Full Text Available Exploring changes of building energy consumption and its relationships with climate can provide basis for energy-saving and carbon emission reduction. Heating and cooling energy consumption of different types of buildings during 1981-2010 in Tianjin city, was simulated by using TRNSYS software. Daily or hourly extreme energy consumption was determined by percentile methods, and the climate impact on extreme energy consumption was analyzed. The results showed that days of extreme heating consumption showed apparent decrease during the recent 30 years for residential and large venue buildings, whereas days of extreme cooling consumption increased in large venue building. No significant variations were found for the days of extreme energy consumption for commercial building, although a decreasing trend in extreme heating energy consumption. Daily extreme energy consumption for large venue building had no relationship with climate parameters, whereas extreme energy consumption for commercial and residential buildings was related to various climate parameters. Further multiple regression analysis suggested heating energy consumption for commercial building was affected by maximum temperature, dry bulb temperature, solar radiation and minimum temperature, which together can explain 71.5 % of the variation of the daily extreme heating energy consumption. The daily extreme cooling energy consumption for commercial building was only related to the wet bulb temperature (R2= 0.382. The daily extreme heating energy consumption for residential building was affected by 4 climate parameters, but the dry bulb temperature had the main impact. The impacts of climate on hourly extreme heating energy consumption has a 1-3 hour delay in all three types of buildings, but no delay was found in the impacts of climate on hourly extreme cooling energy consumption for the selected buildings.

Polygenic determinants in extremes of high-density lipoprotein cholesterol[S

Science.gov (United States)

Dron, Jacqueline S.; Wang, Jian; Low-Kam, Cécile; Khetarpal, Sumeet A.; Robinson, John F.; McIntyre, Adam D.; Ban, Matthew R.; Cao, Henian; Rhainds, David; Dubé, Marie-Pierre; Rader, Daniel J.; Lettre, Guillaume; Tardif, Jean-Claude

2017-01-01

HDL cholesterol (HDL-C) remains a superior biochemical predictor of CVD risk, but its genetic basis is incompletely defined. In patients with extreme HDL-C concentrations, we concurrently evaluated the contributions of multiple large- and small-effect genetic variants. In a discovery cohort of 255 unrelated lipid clinic patients with extreme HDL-C levels, we used a targeted next-generation sequencing panel to evaluate rare variants in known HDL metabolism genes, simultaneously with common variants bundled into a polygenic trait score. Two additional cohorts were used for validation and included 1,746 individuals from the Montréal Heart Institute Biobank and 1,048 individuals from the University of Pennsylvania. Findings were consistent between cohorts: we found rare heterozygous large-effect variants in 18.7% and 10.9% of low- and high-HDL-C patients, respectively. We also found common variant accumulation, indicated by extreme polygenic trait scores, in an additional 12.8% and 19.3% of overall cases of low- and high-HDL-C extremes, respectively. Thus, the genetic basis of extreme HDL-C concentrations encountered clinically is frequently polygenic, with contributions from both rare large-effect and common small-effect variants. Multiple types of genetic variants should be considered as contributing factors in patients with extreme dyslipidemia. PMID:28870971

Radiography Capabilities for Matter-Radiation Interactions in Extremes

Energy Technology Data Exchange (ETDEWEB)

Walstrom, Peter Lowell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Garnett, Robert William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chapman, Catherine A. B [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Salazar, Harry Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Otoole, Joseph Alfred [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Barber, Ronald L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gomez, Tony Simon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-04-28

The Matter-Radiation Interactions in Extremes (MaRIE) experimental facility will be used to discover and design the advanced materials needed to meet 21st century national security and energy security challenges. This new facility will provide the new tools scientists need to develop next-generation materials that will perform predictably and on-demand for currently unattainable lifetimes in extreme environments. The MaRIE facility is based on upgrades to the existing LANSCE 800-MeV proton linac and a new 12-GeV electron linac and associated X-ray FEL to provide simultaneous multiple probe beams, and new experimental areas. In addition to the high-energy photon probe beam, both electron and proton radiography capabilities will be available at the MaRIE facility. Recently, detailed radiography system studies have been performed to develop conceptual layouts of high-magnification electron and proton radiography systems that can meet the experimental requirements for the expected first experiments to be performed at the facility. A description of the radiography systems, their performance requirements, and a proposed facility layout are presented.

Lithium-rich very metal-poor stars discovered with LAMOST and Subaru

Science.gov (United States)

Aoki, Wako; Li, Haining; Matsuno, Tadafumi; Kumar, Yerra Bharat; Shi, Jianrong; Suda, Takuma; Zhao, Gang

2018-04-01

Lithium is a unique element that is produced in the Big Bang nucleosynthesis but is destroyed by nuclear reactions inside stars. As a result, almost constant lithium abundance is found in unevolved main-sequence metal-poor stars, although the value is systematically lower than that expected from the standard Big Bang nucleosynthesis models, whereas lithium abundances of red giants are more than one order of magnitudes lower than those of unevolved stars. There are, however, a small fraction of metal-poor stars that show extremely high lithium abundances, which is not explained by standard stellar evolution models. We have discovered 12 new very metal-poor stars that have enhancement of lithium by more than 10 times compared with typical metal-poor stars at similar evolutionary stages by the large-scale spectroscopic survey with LAMOST and the follow-up high-resolution spectroscopy with the Subaru Telescope. The sample shows a wide distribution of evolutionary stages from subgiants to red giants with the metallicity of -3.3 <[Fe/H]< -1.6. The chemical abundance ratios of other elements have been obtained by our spectroscopic study, and an estimate of the binary frequency by radial velocity monitoring is ongoing. The observational results provide new constraints on the scenarios to explain lithium-rich metal-poor stars, such as extra mixing during the evolution along the red giant branch, mass-transfer from a companion AGB star, and engulfment of planet-like objects. These explanations are very unlikely for at least some of lithium-rich objects in our sample, suggesting a new mechanism that enhances lithium during the low-mass star evolution.

Mesothelioma With a Large Prevascular Lymph Node: N1 Involvement or Something Different?

Science.gov (United States)

Berzenji, Lawek; Van Schil, Paul E; Snoeckx, Annemie; Hertoghs, Marjan; Carp, Laurens

2018-05-01

A 64-year-old man presented with a large amount of right-sided pleural fluid on imaging, together with calcified pleural plaques and an enlarged nodular structure in the prevascular mediastinum, presumably an enlarged lymph node. Pleural biopsies were obtained during video-assisted thoracoscopic surgery to exclude malignancy. Histopathology showed an epithelial malignant pleural mesothelioma. Induction chemotherapy with cisplatin and pemetrexed was administered followed by an extended pleurectomy and decortication with systematic nodal dissection. Histopathology confirmed the diagnosis of a ypT3N0M0 (stage IB) mesothelioma, and an unexpected thymoma type B2 (stage II) was discovered in the prevascular nodule. Simultaneous occurrence of a mesothelioma and thymoma is extremely rare. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

ROSAT Discovers Unique, Distant Cluster of Galaxies

Science.gov (United States)

1995-06-01

Brightest X-ray Cluster Acts as Strong Gravitational Lens Based on exciting new data obtained with the ROSAT X-ray satellite and a ground-based telescope at the ESO La Silla Observatory, a team of European astronomers [2] has just discovered a very distant cluster of galaxies with unique properties. It emits the strongest X-ray emission of any cluster ever observed by ROSAT and is accompanied by two extraordinarily luminous arcs that represent the gravitationally deflected images of even more distant objects. The combination of these unusual characteristics makes this cluster, now known as RXJ1347.5-1145, a most interesting object for further cosmological studies. DISCOVERY AND FOLLOW-UP OBSERVATIONS This strange cluster of galaxies was discovered during the All Sky Survey with the ROSAT X-ray satellite as a moderately intense X-ray source in the constellation of Virgo. It could not be identified with any already known object and additional ground-based observations were therefore soon after performed with the Max-Planck-Society/ESO 2.2-metre telescope at the La Silla observatory in Chile. These observations took place within a large--scale redshift survey of X-ray clusters of galaxies detected by the ROSAT All Sky Survey, a so-called ``ESO Key Programme'' led by astronomers from the Max-Planck-Institut fur Extraterrestrische Physik and the Osservatorio Astronomico di Brera. The main aim of this programme is to identify cluster X-ray sources, to determine the distance to the X-ray emitting clusters and to investigate their overall properties. These observations permitted to measure the redshift of the RXJ1347.5-1145 cluster as z = 0.45, i.e. it moves away from us with a velocity (about 106,000 km/sec) equal to about one-third of the velocity of light. This is an effect of the general expansion of the universe and it allows to determine the distance as about 5,000 million light-years (assuming a Hubble constant of 75 km/sec/Mpc). In other words, we see these

Heavy Tail Behavior of Rainfall Extremes across Germany

Science.gov (United States)

Castellarin, A.; Kreibich, H.; Vorogushyn, S.; Merz, B.

2017-12-01

Distributions are termed heavy-tailed if extreme values are more likely than would be predicted by probability distributions that have exponential asymptotic behavior. Heavy-tail behavior often leads to surprise, because historical observations can be a poor guide for the future. Heavy-tail behavior seems to be widespread for hydro-meteorological extremes, such as extreme rainfall and flood events. To date there have been only vague hints to explain under which conditions these extremes show heavy-tail behavior. We use an observational data set consisting of 11 climate variables at 1440 stations across Germany. This homogenized, gap-free data set covers 110 years (1901-2010) at daily resolution. We estimate the upper tail behavior, including its uncertainty interval, of daily precipitation extremes for the 1,440 stations at the annual and seasonal time scales. Different tail indicators are tested, including the shape parameter of the Generalized Extreme Value distribution, the upper tail ratio and the obesity index. In a further step, we explore to which extent the tail behavior can be explained by geographical and climate factors. A large number of characteristics is derived, such as station elevation, degree of continentality, aridity, measures for quantifying the variability of humidity and wind velocity, or event-triggering large-scale atmospheric situation. The link between the upper tail behavior and these characteristics is investigated via data mining methods capable of detecting non-linear relationships in large data sets. This exceptionally rich observational data set, in terms of number of stations, length of time series and number of explaining variables, allows insights into the upper tail behavior which is rarely possible given the typical observational data sets available.

Irradiated large segment allografts in limb saving surgery for extremity tumor - Philippine experience

International Nuclear Information System (INIS)

Wang, E.H.M.; Agcaoili, N.; Turqueza, M.S.

1999-01-01

Limb saving surgery has only recently become an option in the Phillipines. This has given a better comprehension of oncologic principles and from the refinement of bone-reconstruction procedures. Foremost among the latter is the use of large segment bone allografts. Large-segment allografts (LSA) are available from the Tissue and Bone Bank of the University of the Philippines (UP). After harvest, these bones are processed at the Bank, radiation-sterilized at the Philippine Nuclear Research Institute, and then stored in a -80 degree C deep freezer. We present our 4-year experience (Jan 93 - Dec 96) with LSA for limb saving surgery in musculoskeletal tumors. All patients included had: (1) malignant or aggressive extremity tumors; (2) surgery performed by the UP - Musculoskeletal Tumor Unit (UP-MUST Unit); (3) reconstructions utilizing irradiated large-segment allografts from the UP Tissue and Bone Bank; and (4) follow-up of at least one year or until death. Tumors included osteosarcoma (6) giant cell tumors (11), and metastatic lesions (3). Age ranged from 16-64 years old; 13 males and 7 females. Bones involved were the femur (12) tibia (5) and humerus (3). Average defect length was 15 cm and surgeries performed were intercalary replacement (5), resection arthrodesis (11), hemicondylar allograft (3), and allograft-prosthesis-composite (1). Follow-up ranged was from 17- 60 months or until death. Fifteen (1 5) were alive with NED (no evidence of disease), 3 were dead (2 of disease 1 of other causes), and 2 were AWED (alive with evidence of disease). Functional evaluation using the criteria of the International Society of Limb Salvage (ISOLS) was performed on 18 patients. This averaged 27.5 out of 30 points (92%) for 15 patients. Many having returned to their previous work and recreation. The 3 failures were due to infections in 2 cases (both of whom opted for amputations but who have not been fit with prostheses), and a fracture (secondary to a fall) in one case. Limb

Modulation of extreme temperatures in Europe under extreme values of the North Atlantic Oscillation Index.

Science.gov (United States)

Beniston, Martin

2018-03-10

This paper reports on the influence that extreme values in the tails of the North Atlantic Oscillation (NAO) Index probability density function (PDF) can exert on temperatures in Europe. When the NAO Index enters into its lowest (10% quantile or less) and highest (90% quantile or higher) modes, European temperatures often exhibit large negative or positive departures from their mean values, respectively. Analyses of the joint quantiles of the Index and temperatures (i.e., the simultaneous exceedance of particular quantile thresholds by the two variables) show that temperatures enter into the upper or lower tails of their PDF when the NAO Index also enters into its extreme tails, more often that could be expected from random statistics. Studies of this nature help further our understanding of the manner by which mechanisms of decadal-scale climate variability can influence extremes of temperature-and thus perhaps improve the forecasting of extreme temperatures in weather and climate models. © 2018 New York Academy of Sciences.

Extreme Conditions Modeling Workshop Report

Energy Technology Data Exchange (ETDEWEB)

Coe, R. G.; Neary, V. S.; Lawson, M. J.; Yu, Y.; Weber, J.

2014-07-01

Sandia National Laboratories (SNL) and the National Renewable Energy Laboratory (NREL) hosted the Wave Energy Converter (WEC) Extreme Conditions Modeling (ECM) Workshop in Albuquerque, NM on May 13th-14th, 2014. The objective of the workshop was to review the current state of knowledge on how to model WECs in extreme conditions (e.g. hurricanes and other large storms) and to suggest how U.S. Department of Energy (DOE) and national laboratory resources could be used to improve ECM methods for the benefit of the wave energy industry.

A single pH fluorescent probe for biosensing and imaging of extreme acidity and extreme alkalinity.

Science.gov (United States)

Chao, Jian-Bin; Wang, Hui-Juan; Zhang, Yong-Bin; Li, Zhi-Qing; Liu, Yu-Hong; Huo, Fang-Jun; Yin, Cai-Xia; Shi, Ya-Wei; Wang, Juan-Juan

2017-07-04

A simple tailor-made pH fluorescent probe 2-benzothiazole (N-ethylcarbazole-3-yl) hydrazone (Probe) is facilely synthesized by the condensation reaction of 2-hydrazinobenzothiazole with N-ethylcarbazole-3-formaldehyde, which is a useful fluorescent probe for monitoring extremely acidic and alkaline pH, quantitatively. The pH titrations indicate that Probe displays a remarkable emission enhancement with a pK a of 2.73 and responds linearly to minor pH fluctuations within the extremely acidic range of 2.21-3.30. Interestingly, Probe also exhibits strong pH-dependent characteristics with pK a 11.28 and linear response to extreme-alkalinity range of 10.41-12.43. In addition, Probe shows a large Stokes shift of 84 nm under extremely acidic and alkaline conditions, high selectivity, excellent sensitivity, good water-solubility and fine stability, all of which are favorable for intracellular pH imaging. The probe is further successfully applied to image extremely acidic and alkaline pH values fluctuations in E. coli cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Spatial dependence of extreme rainfall

Science.gov (United States)

Radi, Noor Fadhilah Ahmad; Zakaria, Roslinazairimah; Satari, Siti Zanariah; Azman, Muhammad Az-zuhri

2017-05-01

This study aims to model the spatial extreme daily rainfall process using the max-stable model. The max-stable model is used to capture the dependence structure of spatial properties of extreme rainfall. Three models from max-stable are considered namely Smith, Schlather and Brown-Resnick models. The methods are applied on 12 selected rainfall stations in Kelantan, Malaysia. Most of the extreme rainfall data occur during wet season from October to December of 1971 to 2012. This period is chosen to assure the available data is enough to satisfy the assumption of stationarity. The dependence parameters including the range and smoothness, are estimated using composite likelihood approach. Then, the bootstrap approach is applied to generate synthetic extreme rainfall data for all models using the estimated dependence parameters. The goodness of fit between the observed extreme rainfall and the synthetic data is assessed using the composite likelihood information criterion (CLIC). Results show that Schlather model is the best followed by Brown-Resnick and Smith models based on the smallest CLIC's value. Thus, the max-stable model is suitable to be used to model extreme rainfall in Kelantan. The study on spatial dependence in extreme rainfall modelling is important to reduce the uncertainties of the point estimates for the tail index. If the spatial dependency is estimated individually, the uncertainties will be large. Furthermore, in the case of joint return level is of interest, taking into accounts the spatial dependence properties will improve the estimation process.

Portfolio optimization for heavy-tailed assets: Extreme Risk Index vs. Markowitz

OpenAIRE

Mainik, Georg; Mitov, Georgi; Rüschendorf, Ludger

2015-01-01

Using daily returns of the S&P 500 stocks from 2001 to 2011, we perform a backtesting study of the portfolio optimization strategy based on the extreme risk index (ERI). This method uses multivariate extreme value theory to minimize the probability of large portfolio losses. With more than 400 stocks to choose from, our study seems to be the first application of extreme value techniques in portfolio management on a large scale. The primary aim of our investigation is the potential of ERI in p...

Preconditioned iterations to calculate extreme eigenvalues

Energy Technology Data Exchange (ETDEWEB)

Brand, C.W.; Petrova, S. [Institut fuer Angewandte Mathematik, Leoben (Austria)

1994-12-31

Common iterative algorithms to calculate a few extreme eigenvalues of a large, sparse matrix are Lanczos methods or power iterations. They converge at a rate proportional to the separation of the extreme eigenvalues from the rest of the spectrum. Appropriate preconditioning improves the separation of the eigenvalues. Davidson`s method and its generalizations exploit this fact. The authors examine a preconditioned iteration that resembles a truncated version of Davidson`s method with a different preconditioning strategy.

Extreme physics take a quantum leap... to the edge of science

CERN Document Server

Basher, Simon

2013-01-01

In Basher's totally hip and quirky style, readers are introduced to the amazing research that is revolutionizing physics! From the pioneering experiments taking place in the Hadron Collider to NASAs deep-space exploration, "Basher Science: Extreme Physics "highlights the realm of miniscule things that was discovered in the early 1900s by scientists who were on the hunt for teeny-tiny parts of matter, the bits from which all larger things are made. This wild, uncertain world is bursting with crazy characters you're about to meet-youre gonna love them!

Large-Scale Skin Resurfacing of the Upper Extremity in Pediatric Patients Using a Pre-Expanded Intercostal Artery Perforator Flap.

Science.gov (United States)

Wei, Jiao; Herrler, Tanja; Gu, Bin; Yang, Mei; Li, Qingfeng; Dai, Chuanchang; Xie, Feng

2018-05-01

The repair of extensive upper limb skin lesions in pediatric patients is extremely challenging due to substantial limitations of flap size and donor-site morbidity. We aimed to create an oversize preexpanded flap based on intercostal artery perforators for large-scale resurfacing of the upper extremity in children. Between March 2013 and August 2016, 11 patients underwent reconstructive treatment for extensive skin lesions in the upper extremity using a preexpanded intercostal artery perforator flap. Preoperatively, 2 to 4 candidate perforators were selected as potential pedicle vessels based on duplex ultrasound examination. After tissue expander implantation in the thoracodorsal area, regular saline injections were performed until the expanded flap was sufficient in size. Then, a pedicled flap was formed to resurface the skin lesion of the upper limb. The pedicles were transected 3 weeks after flap transfer. Flap survival, complications, and long-term outcome were evaluated. The average time of tissue expansion was 133 days with a mean final volume of 1713 mL. The thoracoabdominal flaps were based on 2 to 6 pedicles and used to resurface a mean skin defect area of 238 cm ranging from 180 to 357 cm. In all cases, primary donor-site closure was achieved. Marginal necrosis was seen in 5 cases. The reconstructed limbs showed satisfactory outcome in both aesthetic and functional aspects. The preexpanded intercostal artery perforator flap enables 1-block repair of extensive upper limb skin lesions. Due to limited donor-site morbidity and a pedicled technique, this resurfacing approach represents a useful tool especially in pediatric patients.

Extreme value theory and statistics for heavy tail data

NARCIS (Netherlands)

S. Caserta; C.G. de Vries (Casper)

2003-01-01

textabstractA scientific way of looking beyond the worst-case return is to employ statistical extreme value methods. Extreme Value Theory (EVT) shows that the probability on very large losses is eventually governed by a simple function, regardless the specific distribution that underlies the return

Medicinal benefits of marine invertebrates: sources for discovering natural drug candidates.

Science.gov (United States)

De Zoysa, Mahanama

2012-01-01

Marine invertebrates are one of the major groups of organisms, which could be diversified under the major taxonomic groups of Porifera, Cnidaria, Mollusca, Arthropoda, Echinodermata, and many other minor phyla. To date, range of medicinal benefits and a significant number of marine natural products (MNPs) have been discovered from marine invertebrates. Seafood diet from edible marine invertebrates such as mollusks and crustaceans has been linked with various medicinal benefits to improve human health. Among marine invertebrates, spongers from phylum Porifera is the most dominant group responsible for discovering large number of MNPs, which have been used as template to develop therapeutic drugs. MNPs isolated from invertebrates have shown wide range of therapeutic properties including antimicrobial, antioxidant, antihypertensive, anticoagulant, anticancer, anti-inflammatory, wound healing and immune modulator, and other medicinal effects. Therefore, marine invertebrates are rich sources of chemical diversity and health benefits for developing drug candidates, cosmetics, nutritional supplements, and molecular probes that can be supported to increase the healthy life span of human. Copyright © 2012 Elsevier Inc. All rights reserved.

Extreme climate in China. Facts, simulation and projection

Energy Technology Data Exchange (ETDEWEB)

Wang, Hui-Jun; Sun, Jian-Qi; Chen, Huo-Po; Zhu, Ya-Li; Zhang, Ying; Jiang, Da-Bang; Lang, Xian-Mei; Fan, Ke; Yu, En-Tao [Chinese Academy of Sciences, Beijing (China). Inst. of Atmospheric Physics; Yang, Song [NOAA Climate Prediction Center, Camp Springs, MD (United States)

2012-06-15

In this paper, studies on extreme climate in China including extreme temperature and precipitation, dust weather activity, tropical cyclone activity, intense snowfall and cold surge activity, floods, and droughts are reviewed based on the peer-reviewed publications in recent decades. The review is focused first on the climatological features, variability, and trends in the past half century and then on simulations and projections based on global and regional climate models. As the annual mean surface air temperature (SAT) increased throughout China, heat wave intensity and frequency overall increased in the past half century, with a large rate after the 1980s. The daily or yearly minimum SAT increased more significantly than the mean or maximum SAT. The long-term change in precipitation is predominantly characterized by the so-called southern flood and northern drought pattern in eastern China and by the overall increase over Northwest China. The interdecadal variation of monsoon, represented by the monsoon weakening in the end of 1970s, is largely responsible for this change in mean precipitation. Precipitation-related extreme events (e.g., heavy rainfall and intense snowfall) have become more frequent and intense generally over China in the recent years, with large spatial features. Dust weather activity, however, has become less frequent over northern China in the recent years, as result of weakened cold surge activity, reinforced precipitation, and improved vegetation condition. State-of-the-art climate models are capable of reproducing some features of the mean climate and extreme climate events. However, discrepancies among models in simulating and projecting the mean and extreme climate are also demonstrated by many recent studies. Regional models with higher resolutions often perform better than global models. To predict and project climate variations and extremes, many new approaches and schemes based on dynamical models, statistical methods, or their

Seasonal temperature extremes in Potsdam

Science.gov (United States)

Kundzewicz, Zbigniew; Huang, Shaochun

2010-12-01

The awareness of global warming is well established and results from the observations made on thousands of stations. This paper complements the large-scale results by examining a long time-series of high-quality temperature data from the Secular Meteorological Station in Potsdam, where observation records over the last 117 years, i.e., from January 1893 are available. Tendencies of change in seasonal temperature-related climate extremes are demonstrated. "Cold" extremes have become less frequent and less severe than in the past, while "warm" extremes have become more frequent and more severe. Moreover, the interval of the occurrence of frost has been decreasing, while the interval of the occurrence of hot days has been increasing. However, many changes are not statistically significant, since the variability of temperature indices at the Potsdam station has been very strong.

Attribution of extreme rainfall from Hurricane Harvey, August 2017

NARCIS (Netherlands)

Van Oldenborgh, Geert Jan; Van Der Wiel, Karin; Sebastian, A.G.; Singh, Roop; Arrighi, Julie; Otto, Friederike; Haustein, Karsten; Li, Sihan; Vecchi, Gabriel; Cullen, Heidi

2017-01-01

During August 25-30, 2017, Hurricane Harvey stalled over Texas and caused extreme precipitation, particularly over Houston and the surrounding area on August 26-28. This resulted in extensive flooding with over 80 fatalities and large economic costs. It was an extremely rare event: the return

THE SYNTHETIC-OVERSAMPLING METHOD: USING PHOTOMETRIC COLORS TO DISCOVER EXTREMELY METAL-POOR STARS

Energy Technology Data Exchange (ETDEWEB)

Miller, A. A., E-mail: amiller@astro.caltech.edu [Jet Propulsion Laboratory, 4800 Oak Grove Drive, MS 169-506, Pasadena, CA 91109 (United States)

2015-09-20

Extremely metal-poor (EMP) stars ([Fe/H] ≤ −3.0 dex) provide a unique window into understanding the first generation of stars and early chemical enrichment of the universe. EMP stars are exceptionally rare, however, and the relatively small number of confirmed discoveries limits our ability to exploit these near-field probes of the first ∼500 Myr after the Big Bang. Here, a new method to photometrically estimate [Fe/H] from only broadband photometric colors is presented. I show that the method, which utilizes machine-learning algorithms and a training set of ∼170,000 stars with spectroscopically measured [Fe/H], produces a typical scatter of ∼0.29 dex. This performance is similar to what is achievable via low-resolution spectroscopy, and outperforms other photometric techniques, while also being more general. I further show that a slight alteration to the model, wherein synthetic EMP stars are added to the training set, yields the robust identification of EMP candidates. In particular, this synthetic-oversampling method recovers ∼20% of the EMP stars in the training set, at a precision of ∼0.05. Furthermore, ∼65% of the false positives from the model are very metal-poor stars ([Fe/H] ≤ −2.0 dex). The synthetic-oversampling method is biased toward the discovery of warm (∼F-type) stars, a consequence of the targeting bias from the Sloan Digital Sky Survey/Sloan Extension for Galactic Understanding survey. This EMP selection method represents a significant improvement over alternative broadband optical selection techniques. The models are applied to >12 million stars, with an expected yield of ∼600 new EMP stars, which promises to open new avenues for exploring the early universe.

Tools and strategies for discovering novel enzymes and metabolic pathways

Directory of Open Access Journals (Sweden)

John A. Gerlt

2016-12-01

Full Text Available The number of entries in the sequence databases continues to increase exponentially – the UniProt database is increasing with a doubling time of ∼4 years (2% increase/month. Approximately 50% of the entries have uncertain, unknown, or incorrect function annotations because these are made by automated methods based on sequence homology. If the potential in complete genome sequences is to be realized, strategies and tools must be developed to facilitate experimental assignment of functions to uncharacterized proteins discovered in genome projects. The Enzyme Function Initiative (EFI; previously supported by U54GM093342 from the National Institutes of Health, now supported by P01GM118303 developed web tools for visualizing and analyzing (1 sequence and function space in protein families (EFI-EST and (2 genome neighbourhoods in microbial and fungal genomes (EFI-GNT to assist the design of experimental strategies for discovering the in vitro activities and in vivo metabolic functions of uncharacterized enzymes. The EFI developed an experimental platform for large-scale production of the solute binding proteins (SBPs for ABC, TRAP, and TCT transport systems and their screening with a physical ligand library to identify the identities of the ligands for these transport systems. Because the genes that encode transport systems are often co-located with the genes that encode the catabolic pathways for the transported solutes, the identity of the SBP ligand together with the EFI-EST and EFI-GNT web tools can be used to discover new enzyme functions and new metabolic pathways. This approach is demonstrated with the characterization of a novel pathway for ethanolamine catabolism.

Extreme Dependence in Asset Markets Around the Globe

NARCIS (Netherlands)

T.D. Markwat (Thijs)

2011-01-01

textabstractThe dependence between large stock returns is higher than the dependence between small to moderate stock returns. This is defined as extreme dependence, and it is particularly observed for large negative returns. Therefore, diversification gains calculated from the overall dependence

Discovering a Light Scalar or Pseudoscalar at The Large Hadron Collider

DEFF Research Database (Denmark)

Frandsen, Mads Toudal; Sannino, Francesco

2012-01-01

The allowed standard model Higgs mass range has been reduced to a region between 114 and 130 GeV or above 500 GeV, at the 99% confidence level, since the Large Hadron Collider (LHC) program started. Furthermore some of the experiments at Tevatron and LHC observe excesses that could arise from...

Utilizing NASA DISCOVER-AQ Data to Examine Spatial Gradients in Complex Emission Environments

Science.gov (United States)

Buzanowicz, M. E.; Moore, W.; Crawford, J. H.; Schroeder, J.

2017-12-01

Although many regulations have been enacted with the goal of improving air quality, many parts of the US are still classified as `non-attainment areas' because they frequently violate federal air quality standards. Adequately monitoring the spatial distribution of pollutants both within and outside of non-attainment areas has been an ongoing challenge for regulators. Observations of near-surface pollution from space-based platforms would provide an unprecedented view of the spatial distribution of pollution, but this goal has not yet been realized due to fundamental limitations of satellites, specifically because the footprint size of satellite measurements may not be sufficiently small enough to capture true gradients in pollution, and rather represents an average over a large area. NASA's DISCOVER-AQ was a multi-year field campaign aimed at improving our understanding of the role that remote sensing, including satellite-based remote sensing, could play in air quality monitoring systems. DISCOVER-AQ data will be utilized to create a metric to examine spatial gradients and how satellites can capture those gradients in areas with complex emission environments. Examining horizontal variability within a vertical column is critical to understanding mixing within the atmosphere. Aircraft spirals conducted during DISCOVER-AQ were divided into octants, and averages of a given a species were calculated, with certain points receiving a flag. These flags were determined by calculating gradients between subsequent octants. Initial calculations have shown that over areas with large point source emissions, such as Platteville and Denver-La Casa in Colorado, and Essex, Maryland, satellite retrievals may not adequately capture spatial variability in the atmosphere, thus complicating satellite inversion techniques and limiting our ability to understand human exposure on sub-grid scales. Further calculations at other locations and for other trace gases are necessary to determine

Flood protection diversification to reduce probabilities of extreme losses.

Science.gov (United States)

Zhou, Qian; Lambert, James H; Karvetski, Christopher W; Keisler, Jeffrey M; Linkov, Igor

2012-11-01

Recent catastrophic losses because of floods require developing resilient approaches to flood risk protection. This article assesses how diversification of a system of coastal protections might decrease the probabilities of extreme flood losses. The study compares the performance of portfolios each consisting of four types of flood protection assets in a large region of dike rings. A parametric analysis suggests conditions in which diversifications of the types of included flood protection assets decrease extreme flood losses. Increased return periods of extreme losses are associated with portfolios where the asset types have low correlations of economic risk. The effort highlights the importance of understanding correlations across asset types in planning for large-scale flood protection. It allows explicit integration of climate change scenarios in developing flood mitigation strategy. © 2012 Society for Risk Analysis.

Extreme Weather and Climate: Workshop Report

Science.gov (United States)

Sobel, Adam; Camargo, Suzana; Debucquoy, Wim; Deodatis, George; Gerrard, Michael; Hall, Timothy; Hallman, Robert; Keenan, Jesse; Lall, Upmanu; Levy, Marc;

UBVRc Ic ANALYSIS OF THE RECENTLY DISCOVERED TOTALLY ECLIPSING EXTREME MASS RATIO BINARY V1853 ORIONIS, AND A STATISTICAL LOOK AT 25 OTHER EXTREME MASS RATIO SOLAR-TYPE CONTACT BINARIES

International Nuclear Information System (INIS)

Samec, R. G.; Labadorf, C. M.; Hawkins, N. C.; Faulkner, D. R.; Van Hamme, W.

2011-01-01

We present precision CCD light curves, a period study, photometrically derived standard magnitudes, and a five-color simultaneous Wilson code solution of the totally eclipsing, yet shallow amplitude (A v ∼ 0.4 mag) eclipsing, binary V1853 Orionis. It is determined to be an extreme mass ratio, q = 0.20, W-type W UMa overcontact binary. From our standard star observations, we find that the variable is a late-type F spectral-type dwarf, with a secondary component of about 0.24 solar masses (stellar type M5V). Its long eclipse duration (41 minutes) as compared to its period, 0.383 days, attests to the small relative size of the secondary. Furthermore, it has reached a Roche lobe fill-out of ∼50% of its outer critical lobe as it approaches its final stages of binary star evolution, that of a fast spinning single star. Finally, a summary of about 25 extreme mass ratio solar-type binaries is given.

Contribution of large-scale circulation anomalies to changes in extreme precipitation frequency in the United States

Science.gov (United States)

Lejiang Yu; Shiyuan Zhong; Lisi Pei; Xindi (Randy) Bian; Warren E. Heilman

2016-01-01

The mean global climate has warmed as a result of the increasing emission of greenhouse gases induced by human activities. This warming is considered the main reason for the increasing number of extreme precipitation events in the US. While much attention has been given to extreme precipitation events occurring over several days, which are usually responsible for...

Extremely low temperature properties of epoxy GFRP

International Nuclear Information System (INIS)

Kadotani, Kenzo; Nagai, Matao; Aki, Fumitake.

1983-01-01

The examination of fiber-reinforced plastics, that is, plastics such as epoxy, polyester and polyimide reinforced with high strength fibers such as glass, carbon, boron and steel, for extremely low temperature use began from the fuel tanks of rockets. Therafter, the trial manufacture of superconducting generators and extremely low temperature transformers and the manufacture of superconducting magnets for nuclear fusion experimental setups became active, and high performance FRPs have been adopted, of which the extremely low temperature properties have been sufficiently grasped. Recently, the cryostats made of FRPs have been developed, fully utilizing such features of FRPs as high strength, high rigidity, non-magnetic material, insulation, low heat conductivity, light weight and the freedom of molding. In this paper, the mechanical properties at extremely low temperature of the plastic composite materials used as insulators and structural materials for extremely low temperature superconducting equipment is outlined, and in particular, glass fiber-reinforced epoxy laminates are described somewhat in detail. The fracture strain of GFRP at extremely low temperature is about 1.3 times as large as that at room temperature, but at extremely low temperature, clear cracking occurred at 40% of the fracture strain. The linear thermal contraction of GFRP showed remarkable anisotropy. (Kako, I.)

Spitzer SAGE-Spec: Near infrared spectroscopy, dust shells, and cool envelopes in extreme Large Magellanic Cloud asymptotic giant branch stars

Energy Technology Data Exchange (ETDEWEB)

Blum, R. D. [NOAO, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Srinivasan, S.; Kemper, F.; Ling, B. [Academia Sinica, Institute of Astronomy and Astrophysics, 11F of Astronomy-Mathematics Building, NTU/AS, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Volk, K. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2014-11-01

K-band spectra are presented for a sample of 39 Spitzer Infrared Spectrograph (IRS) SAGE-Spec sources in the Large Magellanic Cloud. The spectra exhibit characteristics in very good agreement with their positions in the near-infrared—Spitzer color-magnitude diagrams and their properties as deduced from the Spitzer IRS spectra. Specifically, the near-infrared spectra show strong atomic and molecular features representative of oxygen-rich and carbon-rich asymptotic giant branch stars, respectively. A small subset of stars was chosen from the luminous and red extreme ''tip'' of the color-magnitude diagram. These objects have properties consistent with dusty envelopes but also cool, carbon-rich ''stellar'' cores. Modest amounts of dust mass loss combine with the stellar spectral energy distribution to make these objects appear extreme in their near-infrared and mid-infrared colors. One object in our sample, HV 915, a known post-asymptotic giant branch star of the RV Tau type, exhibits CO 2.3 μm band head emission consistent with previous work that demonstrates that the object has a circumstellar disk.

Spitzer SAGE-Spec: Near infrared spectroscopy, dust shells, and cool envelopes in extreme Large Magellanic Cloud asymptotic giant branch stars

International Nuclear Information System (INIS)

Blum, R. D.; Srinivasan, S.; Kemper, F.; Ling, B.; Volk, K.

2014-01-01

K-band spectra are presented for a sample of 39 Spitzer Infrared Spectrograph (IRS) SAGE-Spec sources in the Large Magellanic Cloud. The spectra exhibit characteristics in very good agreement with their positions in the near-infrared—Spitzer color-magnitude diagrams and their properties as deduced from the Spitzer IRS spectra. Specifically, the near-infrared spectra show strong atomic and molecular features representative of oxygen-rich and carbon-rich asymptotic giant branch stars, respectively. A small subset of stars was chosen from the luminous and red extreme ''tip'' of the color-magnitude diagram. These objects have properties consistent with dusty envelopes but also cool, carbon-rich ''stellar'' cores. Modest amounts of dust mass loss combine with the stellar spectral energy distribution to make these objects appear extreme in their near-infrared and mid-infrared colors. One object in our sample, HV 915, a known post-asymptotic giant branch star of the RV Tau type, exhibits CO 2.3 μm band head emission consistent with previous work that demonstrates that the object has a circumstellar disk.

Time series analysis of diverse extreme phenomena: universal features

Science.gov (United States)

Eftaxias, K.; Balasis, G.

2012-04-01

The field of study of complex systems holds that the dynamics of complex systems are founded on universal principles that may used to describe a great variety of scientific and technological approaches of different types of natural, artificial, and social systems. We suggest that earthquake, epileptic seizures, solar flares, and magnetic storms dynamics can be analyzed within similar mathematical frameworks. A central property of aforementioned extreme events generation is the occurrence of coherent large-scale collective behavior with very rich structure, resulting from repeated nonlinear interactions among the corresponding constituents. Consequently, we apply the Tsallis nonextensive statistical mechanics as it proves an appropriate framework in order to investigate universal principles of their generation. First, we examine the data in terms of Tsallis entropy aiming to discover common "pathological" symptoms of transition to a significant shock. By monitoring the temporal evolution of the degree of organization in time series we observe similar distinctive features revealing significant reduction of complexity during their emergence. Second, a model for earthquake dynamics coming from a nonextensive Tsallis formalism, starting from first principles, has been recently introduced. This approach leads to an energy distribution function (Gutenberg-Richter type law) for the magnitude distribution of earthquakes, providing an excellent fit to seismicities generated in various large geographic areas usually identified as seismic regions. We show that this function is able to describe the energy distribution (with similar non-extensive q-parameter) of solar flares, magnetic storms, epileptic and earthquake shocks. The above mentioned evidence of a universal statistical behavior suggests the possibility of a common approach for studying space weather, earthquakes and epileptic seizures.

Extreme Networks' 10-Gigabit Ethernet enables

CERN Multimedia

2002-01-01

" Extreme Networks, Inc.'s 10-Gigabit switching platform enabled researchers to transfer one Terabyte of information from Vancouver to Geneva across a single network hop, the world's first large-scale, end-to-end transfer of its kind" (1/2 page).

Fake Superpotential for Large and Small Extremal Black Holes

CERN Document Server

Andrianopoli, L; Ferrara, S; Trigiante, M

2010-01-01

We consider the fist order, gradient-flow, description of the scalar fields coupled to spherically symmetric, asymptotically flat black holes in extended supergravities. Using the identification of the fake superpotential with Hamilton's characteristic function we clarify some of its general properties, showing in particular (besides reviewing the issue of its duality invariance) that W has the properties of a Liapunov's function, which implies that its extrema (associated with the horizon of extremal black holes) are asymptotically stable equilibrium points of the corresponding first order dynamical system (in the sense of Liapunov). Moreover, we show that the fake superpotential W has, along the entire radial flow, the same flat directions which exist at the attractor point. This allows to study properties of the ADM mass also for small black holes where in fact W has no critical points at finite distance in moduli space. In particular the W function for small non-BPS black holes can always be computed anal...

DeBi: Discovering Differentially Expressed Biclusters using a Frequent Itemset Approach

Directory of Open Access Journals (Sweden)

Vingron Martin

2011-06-01

Full Text Available Abstract Background The analysis of massive high throughput data via clustering algorithms is very important for elucidating gene functions in biological systems. However, traditional clustering methods have several drawbacks. Biclustering overcomes these limitations by grouping genes and samples simultaneously. It discovers subsets of genes that are co-expressed in certain samples. Recent studies showed that biclustering has a great potential in detecting marker genes that are associated with certain tissues or diseases. Several biclustering algorithms have been proposed. However, it is still a challenge to find biclusters that are significant based on biological validation measures. Besides that, there is a need for a biclustering algorithm that is capable of analyzing very large datasets in reasonable time. Results Here we present a fast biclustering algorithm called DeBi (Differentially Expressed BIclusters. The algorithm is based on a well known data mining approach called frequent itemset. It discovers maximum size homogeneous biclusters in which each gene is strongly associated with a subset of samples. We evaluate the performance of DeBi on a yeast dataset, on synthetic datasets and on human datasets. Conclusions We demonstrate that the DeBi algorithm provides functionally more coherent gene sets compared to standard clustering or biclustering algorithms using biological validation measures such as Gene Ontology term and Transcription Factor Binding Site enrichment. We show that DeBi is a computationally efficient and powerful tool in analyzing large datasets. The method is also applicable on multiple gene expression datasets coming from different labs or platforms.

Extreme weather: Subtropical floods and tropical cyclones

Science.gov (United States)

Shaevitz, Daniel A.

Extreme weather events have a large effect on society. As such, it is important to understand these events and to project how they may change in a future, warmer climate. The aim of this thesis is to develop a deeper understanding of two types of extreme weather events: subtropical floods and tropical cyclones (TCs). In the subtropics, the latitude is high enough that quasi-geostrophic dynamics are at least qualitatively relevant, while low enough that moisture may be abundant and convection strong. Extratropical extreme precipitation events are usually associated with large-scale flow disturbances, strong ascent, and large latent heat release. In the first part of this thesis, I examine the possible triggering of convection by the large-scale dynamics and investigate the coupling between the two. Specifically two examples of extreme precipitation events in the subtropics are analyzed, the 2010 and 2014 floods of India and Pakistan and the 2015 flood of Texas and Oklahoma. I invert the quasi-geostrophic omega equation to decompose the large-scale vertical motion profile to components due to synoptic forcing and diabatic heating. Additionally, I present model results from within the Column Quasi-Geostrophic framework. A single column model and cloud-revolving model are forced with the large-scale forcings (other than large-scale vertical motion) computed from the quasi-geostrophic omega equation with input data from a reanalysis data set, and the large-scale vertical motion is diagnosed interactively with the simulated convection. It is found that convection was triggered primarily by mechanically forced orographic ascent over the Himalayas during the India/Pakistan flood and by upper-level Potential Vorticity disturbances during the Texas/Oklahoma flood. Furthermore, a climate attribution analysis was conducted for the Texas/Oklahoma flood and it is found that anthropogenic climate change was responsible for a small amount of rainfall during the event but the

Discovering genes underlying QTL

Energy Technology Data Exchange (ETDEWEB)

Vanavichit, Apichart [Kasetsart University, Kamphaengsaen, Nakorn Pathom (Thailand)

2002-02-01

A map-based approach has allowed scientists to discover few genes at a time. In addition, the reproductive barrier between cultivated rice and wild relatives has prevented us from utilizing the germ plasm by a map-based approach. Most genetic traits important to agriculture or human diseases are manifested as observable, quantitative phenotypes called Quantitative Trait Loci (QTL). In many instances, the complexity of the phenotype/genotype interaction and the general lack of clearly identifiable gene products render the direct molecular cloning approach ineffective, thus additional strategies like genome mapping are required to identify the QTL in question. Genome mapping requires no prior knowledge of the gene function, but utilizes statistical methods to identify the most likely gene location. To completely characterize genes of interest, the initially mapped region of a gene location will have to be narrowed down to a size that is suitable for cloning and sequencing. Strategies for gene identification within the critical region have to be applied after the sequencing of a potentially large clone or set of clones that contains this gene(s). Tremendous success of positional cloning has been shown for cloning many genes responsible for human diseases, including cystic fibrosis and muscular dystrophy as well as plant disease resistance genes. Genome and QTL mapping, positional cloning: the pre-genomics era, comparative approaches to gene identification, and positional cloning: the genomics era are discussed in the report. (M. Suetake)

Extreme scattering events towards two young pulsars

Science.gov (United States)

Kerr, M.; Coles, W. A.; Ward, C. A.; Johnston, S.; Tuntsov, A. V.; Shannon, R. M.

2018-03-01

We have measured the scintillation properties of 151 young, energetic pulsars with the Parkes radio telescope and have identified two extreme scattering events (ESEs). Towards PSR J1057-5226, we discovered a 3 yr span of strengthened scattering during which the variability in flux density and the scintillation bandwidth decreased markedly. The transverse size of the scattering region is ˜23 au, and strong flux density enhancement before and after the ESE may arise from refractive focusing. Long observations reveal scintillation arcs characteristic of interference between rays scattered at large angles, and the clearest arcs appear during the ESE. The arcs suggest scattering by a screen 100-200 pc from the Earth, perhaps ionized filamentary structure associated with the boundary of the local bubble(s). Towards PSR J1740-3015, we observed a `double dip' in the measured flux density similar to ESEs observed towards compact extragalactic radio sources. The observed shape is consistent with that produced by a many-au scale diverging plasma lens with electron density ˜500 cm-3. The continuing ESE is at least 1500 d long, making it the longest detected event to date. These detections, with materially different observational signatures, indicate that well-calibrated pulsar monitoring is a keen tool for ESE detection and interstellar medium (ISM) diagnostics. They illustrate the strong role au-scale non-Kolmogorov density fluctuations and the local ISM structure play in such events and are key to understanding both their intrinsic physics and their impact on other phenomena, particularly fast radio bursts.

Predictability and possible earlier awareness of extreme precipitation across Europe

Science.gov (United States)

Lavers, David; Pappenberger, Florian; Richardson, David; Zsoter, Ervin

2017-04-01

Extreme hydrological events can cause large socioeconomic damages in Europe. In winter, a large proportion of these flood episodes are associated with atmospheric rivers, a region of intense water vapour transport within the warm sector of extratropical cyclones. When preparing for such extreme events, forecasts of precipitation from numerical weather prediction models or river discharge forecasts from hydrological models are generally used. Given the strong link between water vapour transport (integrated vapour transport IVT) and heavy precipitation, it is possible that IVT could be used to warn of extreme events. Furthermore, as IVT is located in extratropical cyclones, it is hypothesized to be a more predictable variable due to its link with synoptic-scale atmospheric dynamics. In this research, we firstly provide an overview of the predictability of IVT and precipitation forecasts, and secondly introduce and evaluate the ECMWF Extreme Forecast Index (EFI) for IVT. The EFI is a tool that has been developed to evaluate how ensemble forecasts differ from the model climate, thus revealing the extremeness of the forecast. The ability of the IVT EFI to capture extreme precipitation across Europe during winter 2013/14, 2014/15, and 2015/16 is presented. The results show that the IVT EFI is more capable than the precipitation EFI of identifying extreme precipitation in forecast week 2 during forecasts initialized in a positive North Atlantic Oscillation (NAO) phase. However, the precipitation EFI is superior during the negative NAO phase and at shorter lead times. An IVT EFI example is shown for storm Desmond in December 2015 highlighting its potential to identify upcoming hydrometeorological extremes.

Extreme fluxes in solar energetic particle events: Methodological and physical limitations

International Nuclear Information System (INIS)

Miroshnichenko, L.I.; Nymmik, R.A.

2014-01-01

In this study, all available data on the largest solar proton events (SPEs), or extreme solar energetic particle (SEP) events, for the period from 1561 up to now are analyzed. Under consideration are the observational, methodological and physical problems of energy-spectrum presentation for SEP fluxes (fluences) near the Earth's orbit. Special attention is paid to the study of the distribution function for extreme fluences of SEPs by their sizes. The authors present advances in at least three aspects: 1) a form of the distribution function that was previously obtained from the data for three cycles of solar activity has been completely confirmed by the data for 41 solar cycles; 2) early estimates of extremely large fluences in the past have been critically revised, and their values were found to be overestimated; and 3) extremely large SEP fluxes are shown to obey a probabilistic distribution, so the concept of an “upper limit flux” does not carry any strict physical sense although it serves as an important empirical restriction. SEP fluxes may only be characterized by the relative probabilities of their appearance, and there is a sharp break in the spectrum in the range of large fluences (or low probabilities). It is emphasized that modern observational data and methods of investigation do not allow, for the present, the precise resolution of the problem of the spectrum break or the estimation of the maximum potentialities of solar accelerator(s). This limitation considerably restricts the extrapolation of the obtained results to the past and future for application to the epochs with different levels of solar activity. - Highlights: • All available data on the largest solar proton events (SPEs) are analyzed. • Distribution function obtained for 3 last cycles is confirmed for 41 solar cycles. • Estimates of extremely large fluences in the past are found to be overestimated. • Extremely large SEP fluxes are shown to obey a probabilistic distribution. �

A Generalized Framework for Non-Stationary Extreme Value Analysis

Science.gov (United States)

Ragno, E.; Cheng, L.; Sadegh, M.; AghaKouchak, A.

2017-12-01

Empirical trends in climate variables including precipitation, temperature, snow-water equivalent at regional to continental scales are evidence of changes in climate over time. The evolving climate conditions and human activity-related factors such as urbanization and population growth can exert further changes in weather and climate extremes. As a result, the scientific community faces an increasing demand for updated appraisal of the time-varying climate extremes. The purpose of this study is to offer a robust and flexible statistical tool for non-stationary extreme value analysis which can better characterize the severity and likelihood of extreme climatic variables. This is critical to ensure a more resilient environment in a changing climate. Following the positive feedback on the first version of Non-Stationary Extreme Value Analysis (NEVA) Toolbox by Cheng at al. 2014, we present an improved version, i.e. NEVA2.0. The upgraded version herein builds upon a newly-developed hybrid evolution Markov Chain Monte Carlo (MCMC) approach for numerical parameters estimation and uncertainty assessment. This addition leads to a more robust uncertainty estimates of return levels, return periods, and risks of climatic extremes under both stationary and non-stationary assumptions. Moreover, NEVA2.0 is flexible in incorporating any user-specified covariate other than the default time-covariate (e.g., CO2 emissions, large scale climatic oscillation patterns). The new feature will allow users to examine non-stationarity of extremes induced by physical conditions that underlie the extreme events (e.g. antecedent soil moisture deficit, large-scale climatic teleconnections, urbanization). In addition, the new version offers an option to generate stationary and/or non-stationary rainfall Intensity - Duration - Frequency (IDF) curves that are widely used for risk assessment and infrastructure design. Finally, a Graphical User Interface (GUI) of the package is provided, making NEVA

Characteristics of tropical cyclone extreme precipitation and its preliminary causes in Southeast China

Science.gov (United States)

Qiu, Wenyu; Ren, Fumin; Wu, Liguang; Chen, Lianshou; Ding, Chenchen

2018-03-01

Extreme precipitation induced by a tropical cyclone (TC) is of great concern to Southeast China. Regional characteristics of daily TC-induced extreme precipitation (TCEP) between 1958 and 2016 and the associated preliminary causes over Southeast China (Zhejiang, Fujian, and Shanghai) were examined by applying the objective synoptic analysis technique, TC track similarity area index, daily precipitation observations, and reanalysis data. The intensity and frequency of high-intensity TCEP (≥ 100, ≥ 200, ≥ 300 mm) have had an increasing trend over recent decades. Most of TCEP occurs from July to September, with frequency peaks in August for TCEP at all intensity levels, apart from the frequency for TCEP ≥ 300 mm that peaks in September. Regions with high frequency and large TCEP (R-HFLTs) (relatively high frequency for TCEP ≥ 100 mm) were concentrated along the coastline of the southern coastal Fujian (Southern R-HFLT), the regions from northern coastal Fujian to southernmost coastal Zhejiang (Central R-HFLT), and central coastal Zhejiang (Northern R-HFLT), decreasing from the coastline to inland. The Central R-HFLT region had the highest TCEP intensity and frequency for TCEP ≥ 100 mm compared with the other R-HFLTs. Further analysis showed that the special terrain of Southeast China matched the spatial distribution of TCEP, which highlights the significance of the topography of Southeast China. To discover other factors responsible for the heavy TCEP, we compared two TC groups that influence Central R-HFLT. Under a more northerly direction and slow movement combined with the unique terrain, TCs with stronger vortex circulation generated heavier TCEP during landfall in Central R-HFLT. Heavy TCEP occurred with easterly and southeasterly winds interacting with terrain over the eastern coast for Central R-HFLT. Although large changes in the internal and external environment were sensitive to the observed TCEP intensity, the interaction between TC circulation

Economics of extreme weather events: Terminology and regional impact models

OpenAIRE

Jahn, Malte

2015-01-01

Impacts of extreme weather events are relevant for regional (in the sense of subnational) economies and in particular cities in many aspects. Cities are the cores of economic activity and the amount of people and assets endangered by extreme weather events is large, even under the current climate. A changing climate with changing extreme weather patterns and the process of urbanization will make the whole issue even more relevant in the future. In this paper, definitions and terminology in th...

Comparison of the Effects of Walking with and without Nordic Pole on Upper Extremity and Lower Extremity Muscle Activation.

Science.gov (United States)

Shim, Je-Myung; Kwon, Hae-Yeon; Kim, Ha-Roo; Kim, Bo-In; Jung, Ju-Hyeon

2013-12-01

[Purpose] The aim of this study was to assess the effect of Nordic pole walking on the electromyographic activities of upper extremity and lower extremity muscles. [Subjects and Methods] The subjects were randomly divided into two groups as follows: without Nordic pole walking group (n=13) and with Nordic pole walking group (n=13). The EMG data were collected by measurement while the subjects walking on a treadmill for 30 minutes by measuring from one heel strike to the next. [Results] Both the average values and maximum values of the muscle activity of the upper extremity increased in both the group that used Nordic poles and the group that did not use Nordic poles, and the values showed statistically significant differences. There was an increase in the average value for muscle activity of the latissimus dorsi, but the difference was not statistically significant, although there was a statistically significant increase in its maximum value. The average and maximum values for muscle activity of the lower extremity did not show large differences in either group, and the values did not show any statistically significant differences. [Conclusion] The use of Nordic poles by increased muscle activity of the upper extremity compared with regular walking but did not affect the lower extremity.

New background quasars in the vicinity of the Andromeda Galaxy discovered with the Guoshoujing Telescope (LAMOST)

International Nuclear Information System (INIS)

Huo Zhiying; Liu Xiaowei; Yuan Haibo; Zhang Huihua; Zhang Huawei; Zhao Yongheng; Chen Jianjun; Bai Zhongrui; Zhang Haotong; Yan Hongliang; Ren Juanjuan; Sun Shiwei; GarcIa-Benito, Ruben; Xiang Maosheng; Zhang Yong; Li Yeping; Lu Qishuai; Wang You; Ni Jijun; Wang Hai

2010-01-01

We present preliminary analyses of spectra of quasar candidates in two Guoshoujing Telescope (GSJT, formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope - LAMOST) test fields near M 31 where one is close to the optical center of the disk and the other is towards the northeastern outskirts of the halo, obtained during the early stage of the GSJT commissioning in the last season of 2009. Both fields contain background low-redshift quasar candidates selected from the SDSS photometry. In total, 14 new quasars with redshifts up to 2 and i magnitudes between 16.7 and 19.2, are discovered, including 7 within the 2.5 0 central region of M 31. We briefly discuss the potential applications of these newly discovered bright quasars. (editor's recommendation)

Extreme Conditions Modeling Workshop Report

Energy Technology Data Exchange (ETDEWEB)

Coe, Ryan Geoffrey [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Neary, Vincent Sinclair [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Lawon, Michael J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Lab. (NREL), Golden, CO (United States); Weber, Jochem [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2014-07-01

Sandia National Laboratories (SNL) and the National Renewable Energy Laboratory (NREL) hosted the Wave Energy Converter (WEC) Extreme Conditions Modeling (ECM) Workshop in Albuquerque, New Mexico on May 13–14, 2014. The objective of the workshop was to review the current state of knowledge on how to numerically and experimentally model WECs in extreme conditions (e.g. large ocean storms) and to suggest how national laboratory resources could be used to improve ECM methods for the benefit of the wave energy industry. More than 30 U.S. and European WEC experts from industry, academia, and national research institutes attended the workshop, which consisted of presentations from W EC developers, invited keynote presentations from subject matter experts, breakout sessions, and a final plenary session .

Attribution of climate extreme events

Science.gov (United States)

Trenberth, Kevin E.; Fasullo, John T.; Shepherd, Theodore G.

2015-08-01

There is a tremendous desire to attribute causes to weather and climate events that is often challenging from a physical standpoint. Headlines attributing an event solely to either human-induced climate change or natural variability can be misleading when both are invariably in play. The conventional attribution framework struggles with dynamically driven extremes because of the small signal-to-noise ratios and often uncertain nature of the forced changes. Here, we suggest that a different framing is desirable, which asks why such extremes unfold the way they do. Specifically, we suggest that it is more useful to regard the extreme circulation regime or weather event as being largely unaffected by climate change, and question whether known changes in the climate system's thermodynamic state affected the impact of the particular event. Some examples briefly illustrated include 'snowmaggedon' in February 2010, superstorm Sandy in October 2012 and supertyphoon Haiyan in November 2013, and, in more detail, the Boulder floods of September 2013, all of which were influenced by high sea surface temperatures that had a discernible human component.

A NEW CLASS OF NASCENT ECLIPSING BINARIES WITH EXTREME MASS RATIOS

Energy Technology Data Exchange (ETDEWEB)

Moe, Maxwell; Stefano, Rosanne Di, E-mail: mmoe@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-10, Cambridge, MA 02138 (United States)

2015-03-10

Early B-type main-sequence (MS) stars (M {sub 1} ≈ 5-16 M {sub ☉}) with closely orbiting low-mass stellar companions (q = M {sub 2}/M {sub 1} < 0.25) can evolve to produce Type Ia supernovae, low-mass X-ray binaries, and millisecond pulsars. However, the formation mechanism and intrinsic frequency of such close extreme mass-ratio binaries have been debated, especially considering none have hitherto been detected. Utilizing observations of the Large Magellanic Cloud galaxy conducted by the Optical Gravitational Lensing Experiment, we have discovered a new class of eclipsing binaries in which a luminous B-type MS star irradiates a closely orbiting low-mass pre-MS companion that has not yet fully formed. The primordial pre-MS companions have large radii and discernibly reflect much of the light they intercept from the B-type MS primaries (ΔI {sub refl} ≈ 0.02-0.14 mag). For the 18 definitive MS + pre-MS eclipsing binaries in our sample with good model fits to the observed light-curves, we measure short orbital periods P = 3.0-8.5 days, young ages τ ≈ 0.6-8 Myr, and small secondary masses M {sub 2} ≈ 0.8-2.4 M {sub ☉} (q ≈ 0.07-0.36). The majority of these nascent eclipsing binaries are still associated with stellar nurseries, e.g., the system with the deepest eclipse ΔI {sub 1} = 2.8 mag and youngest age τ = 0.6 ± 0.4 Myr is embedded in the bright H II region 30 Doradus. After correcting for selection effects, we find that (2.0 ± 0.6)% of B-type MS stars have companions with short orbital periods P = 3.0-8.5 days and extreme mass ratios q ≈ 0.06-0.25. This is ≈10 times greater than that observed for solar-type MS primaries. We discuss how these new eclipsing binaries provide invaluable insights, diagnostics, and challenges for the formation and evolution of stars, binaries, and H II regions.

Cardiovascular consequences of extreme prematurity: the EPICure study.

Science.gov (United States)

McEniery, Carmel M; Bolton, Charlotte E; Fawke, Joseph; Hennessy, Enid; Stocks, Janet; Wilkinson, Ian B; Cockcroft, John R; Marlow, Neil

2011-07-01

The long-term consequences of extreme prematurity are becoming increasingly important, given recent improvements in neonatal intensive care. The aim of the current study was to examine the cardiovascular consequences of extreme prematurity in 11-year-olds born at or before 25 completed weeks of gestation. Age and sex-matched classmates were recruited as controls. Information concerning perinatal and maternal history was collected, and current anthropometric characteristics were measured in 219 children born extremely preterm and 153 classmates. A subset of the extremely preterm children (n = 68) and classmates (n = 90) then underwent detailed haemodynamic investigations, including measurement of supine blood pressure (BP), aortic pulse wave velocity (aPWV, a measure of aortic stiffness) and augmentation index (AIx, a measure of arterial pressure wave reflections). Seated brachial systolic and diastolic BP were not different between extremely preterm children and classmates (P = 0.3 for both), although there was a small, significant elevation in supine mean and diastolic BP in the extremely preterm children (P prematurity is associated with altered arterial haemodynamics in children, not evident from the examination of brachial BP alone. Moreover, the smaller, preresistance and resistance vessels rather than large elastic arteries appear to be most affected. Children born extremely preterm may be at increased future cardiovascular risk.

ECMWF Extreme Forecast Index for water vapor transport: A forecast tool for atmospheric rivers and extreme precipitation

Science.gov (United States)

Lavers, David A.; Pappenberger, Florian; Richardson, David S.; Zsoter, Ervin

2016-11-01

In winter, heavy precipitation and floods along the west coasts of midlatitude continents are largely caused by intense water vapor transport (integrated vapor transport (IVT)) within the atmospheric river of extratropical cyclones. This study builds on previous findings that showed that forecasts of IVT have higher predictability than precipitation, by applying and evaluating the European Centre for Medium-Range Weather Forecasts Extreme Forecast Index (EFI) for IVT in ensemble forecasts during three winters across Europe. We show that the IVT EFI is more able (than the precipitation EFI) to capture extreme precipitation in forecast week 2 during forecasts initialized in a positive North Atlantic Oscillation (NAO) phase; conversely, the precipitation EFI is better during the negative NAO phase and at shorter leads. An IVT EFI example for storm Desmond in December 2015 highlights its potential to identify upcoming hydrometeorological extremes, which may prove useful to the user and forecasting communities.

Decision mining revisited - Discovering overlapping rules

NARCIS (Netherlands)

Mannhardt, Felix; De Leoni, Massimiliano; Reijers, Hajo A.; Van Der Aalst, Wil M P

2016-01-01

Decision mining enriches process models with rules underlying decisions in processes using historical process execution data. Choices between multiple activities are specified through rules defined over process data. Existing decision mining methods focus on discovering mutually-exclusive rules,

Decision Mining Revisited - Discovering Overlapping Rules

NARCIS (Netherlands)

Mannhardt, F.; De Leoni, M.; Reijers, H.A.; van der Aalst, W.M.P.; Nurcan, S.; Soffer, P.; Bajec, M.; Eder, J.

2016-01-01

Decision mining enriches process models with rules underlying decisions in processes using historical process execution data. Choices between multiple activities are specified through rules defined over process data. Existing decision mining methods focus on discovering mutually-exclusive rules,

Disaster Risks Reduction for Extreme Natural Hazards

Science.gov (United States)

Plag, H.; Jules-Plag, S.

2013-12-01

Mega disasters associated with extreme natural hazards have the potential to escalate the global sustainability crisis and put us close to the boundaries of the safe operating space for humanity. Floods and droughts are major threats that potentially could reach planetary extent, particularly through secondary economic and social impacts. Earthquakes and tsunamis frequently cause disasters that eventually could exceed the immediate coping capacity of the global economy, particularly since we have built mega cities in hazardous areas that are now ready to be harvested by natural hazards. Unfortunately, the more we learn to cope with the relatively frequent hazards (50 to 100 years events), the less we are worried about the low-probability, high-impact events (a few hundred and more years events). As a consequence, threats from the 500 years flood, drought, volcano eruption are not appropriately accounted for in disaster risk reduction (DRR) discussions. Extreme geohazards have occurred regularly throughout the past, but mostly did not cause major disasters because exposure of human assets to hazards was much lower in the past. The most extreme events that occurred during the last 2,000 years would today cause unparalleled damage on a global scale and could worsen the sustainability crisis. Simulation of these extreme hazards under present conditions can help to assess the disaster risk. Recent extreme earthquakes have illustrated the destruction they can inflict, both directly and indirectly through tsunamis. Large volcano eruptions have the potential to impact climate, anthropogenic infrastructure and resource supplies on global scale. During the last 2,000 years several large volcano eruptions occurred, which under today's conditions are associated with extreme disaster risk. The comparison of earthquakes and volcano eruptions indicates that large volcano eruptions are the low-probability geohazards with potentially the highest impact on our civilization

Science case and requirements for the MOSAIC concept for a multi-object spectrograph for the European extremely large telescope

International Nuclear Information System (INIS)

Evans, C.J.; Puech, M.; Bonifacio, P.; Hammer, F.; Jagourel, P.; Caffau, E.; Disseau, K.; Flores, H.; Huertas-Company, M.; Mei, S.; Aussel, H.

2014-01-01

Over the past 18 months we have revisited the science requirements for a multi-object spectrograph (MOS) for the European Extremely Large Telescope (E-ELT). These efforts span the full range of E-ELT science and include input from a broad cross-section of astronomers across the ESO partner countries. In this contribution we summarise the key cases relating to studies of high-redshift galaxies, galaxy evolution, and stellar populations, with a more expansive presentation of a new case relating to detection of exoplanets in stellar clusters. A general requirement is the need for two observational modes to best exploit the large (=40 arcmin 2 ) patrol field of the E-ELT. The first mode ('high multiplex') requires integrated-light (or coarsely resolved) optical/near-IR spectroscopy of ≥100 objects simultaneously. The second ('high definition'), enabled by wide-field adaptive optics, requires spatially-resolved, near-IR of ≥10 objects/sub-fields. Within the context of the conceptual study for an ELT-MOS called MOSAIC, we summarise the top level requirements from each case and introduce the next steps in the design process. (authors)

Jellyfish: the origin and distribution of extreme ram-pressure stripping events in massive galaxy clusters

Science.gov (United States)

McPartland, Conor; Ebeling, Harald; Roediger, Elke; Blumenthal, Kelly

2016-01-01

We investigate the observational signatures and physical origin of ram-pressure stripping (RPS) in 63 massive galaxy clusters at z = 0.3-0.7, based on images obtained with the Hubble Space Telescope. Using a training set of a dozen `jellyfish' galaxies identified earlier in the same imaging data, we define morphological criteria to select 211 additional, less obvious cases of RPS. Spectroscopic follow-up observations of 124 candidates so far confirmed 53 as cluster members. For the brightest and most favourably aligned systems, we visually derive estimates of the projected direction of motion based on the orientation of apparent compression shocks and debris trails. Our findings suggest that the onset of these events occurs primarily at large distances from the cluster core (>400 kpc), and that the trajectories of the affected galaxies feature high-impact parameters. Simple models show that such trajectories are highly improbable for galaxy infall along filaments but common for infall at high velocities, even after observational biases are accounted for, provided the duration of the resulting RPS events is ≲500 Myr. We thus tentatively conclude that extreme RPS events are preferentially triggered by cluster mergers, an interpretation that is supported by the disturbed dynamical state of many of the host clusters. This hypothesis implies that extreme RPS might occur also near the cores of merging poor clusters or even merging groups of galaxies. Finally, we present nine additional `jellyfish" galaxies at z > 0.3 discovered by us, thereby doubling the number of such systems known at intermediate redshift.

Survival of extremely low-birth-weight infants

African Journals Online (AJOL)

Survival of extremely low-birth-weight (ELBW) infants in a resource-limited public hospital setting is still low in South. Africa. is study aimed ... Mortality as a result of prematurity is the major contributor to .... reported from a large cohort study that.

What happens at the horizon(s) of an extreme black hole?

International Nuclear Information System (INIS)

Murata, Keiju; Reall, Harvey S; Tanahashi, Norihiro

2013-01-01

A massless scalar field exhibits an instability at the event horizon of an extreme black hole. We study numerically the nonlinear evolution of this instability for spherically symmetric perturbations of an extreme Reissner–Nordstrom (RN) black hole. We find that generically the endpoint of the instability is a non-extreme RN solution. However, there exist fine-tuned initial perturbations for which the instability never decays. In this case, the perturbed spacetime describes a time-dependent extreme black hole. Such solutions settle down to extreme RN outside, but not on, the event horizon. The event horizon remains smooth but certain observers who cross it at late time experience large gradients there. Our results indicate that these dynamical extreme black holes admit a C 1 extension across an inner (Cauchy) horizon. (paper)

Astronomers Discover Six-Image Gravitational Lens

Science.gov (United States)

2001-08-01

An international team of astronomers has used the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope and NASA's Hubble Space Telescope (HST) to discover the first gravitational lens in which the single image of a very distant galaxy has been split into six different images. The unique configuration is produced by the gravitational effect of three galaxies along the line of sight between the more-distant galaxy and Earth. Optical and Radio Images of Gravitational Lens "This is the first gravitational lens with more than four images of the background object that is produced by a small group of galaxies rather than a large cluster of galaxies," said David Rusin, who just received his Ph.D. from the University of Pennsylvania. "Such systems are expected to be extremely rare, so this discovery is an important stepping stone. Because this is an intermediate case between gravitational lenses produced by single galaxies and lenses produced by large clusters of galaxies, it will give us insights we can't get from other types of lenses," Rusin added. The gravitational lens, called CLASS B1359+154, consists of a galaxy more than 11 billion light-years away in the constellation Bootes, with a trio of galaxies more than 7 billion light-years away along the same line of sight. The more-distant galaxy shows signs that it contains a massive black hole at its core and also has regions in which new stars are forming. The gravitational effect of the intervening galaxies has caused the light and radio waves from the single, more-distant galaxy to be "bent" to form six images as seen from Earth. Four of these images appear outside the triangle formed by the three intermediate galaxies and two appear inside that triangle. "This lens system is a very interesting case to study because it is more complicated than lenses produced by single galaxies, and yet simpler than lenses produced by clusters of numerous galaxies," said Chris Kochanek of the Harvard

Attribution of extreme rainfall from Hurricane Harvey, August 2017

Science.gov (United States)

van Oldenborgh, Geert Jan; van der Wiel, Karin; Sebastian, Antonia; Singh, Roop; Arrighi, Julie; Otto, Friederike; Haustein, Karsten; Li, Sihan; Vecchi, Gabriel; Cullen, Heidi

2017-12-01

During August 25-30, 2017, Hurricane Harvey stalled over Texas and caused extreme precipitation, particularly over Houston and the surrounding area on August 26-28. This resulted in extensive flooding with over 80 fatalities and large economic costs. It was an extremely rare event: the return period of the highest observed three-day precipitation amount, 1043.4 mm 3dy-1 at Baytown, is more than 9000 years (97.5% one-sided confidence interval) and return periods exceeded 1000 yr (750 mm 3dy-1) over a large area in the current climate. Observations since 1880 over the region show a clear positive trend in the intensity of extreme precipitation of between 12% and 22%, roughly two times the increase of the moisture holding capacity of the atmosphere expected for 1 °C warming according to the Clausius-Clapeyron (CC) relation. This would indicate that the moisture flux was increased by both the moisture content and stronger winds or updrafts driven by the heat of condensation of the moisture. We also analysed extreme rainfall in the Houston area in three ensembles of 25 km resolution models. The first also shows 2 × CC scaling, the second 1 × CC scaling and the third did not have a realistic representation of extreme rainfall on the Gulf Coast. Extrapolating these results to the 2017 event, we conclude that global warming made the precipitation about 15% (8%-19%) more intense, or equivalently made such an event three (1.5-5) times more likely. This analysis makes clear that extreme rainfall events along the Gulf Coast are on the rise. And while fortifying Houston to fully withstand the impact of an event as extreme as Hurricane Harvey may not be economically feasible, it is critical that information regarding the increasing risk of extreme rainfall events in general should be part of the discussion about future improvements to Houston’s flood protection system.

Extreme value analysis of air pollution data and their comparison between two large urban regions of South America

Directory of Open Access Journals (Sweden)

Leila Droprinchinski Martins

2017-12-01

Full Text Available Sixteen years of hourly atmospheric pollutant data (1996–2011 in the Metropolitan Area of São Paulo (MASP, and seven years (2005–2011 of data measured in the Metropolitan Area of Rio de Janeiro (MARJ, were analyzed in order to study the extreme pollution events and their return period. In addition, the objective was to compare the air quality between the two largest Brazilian urban areas and provide information for decision makers, government agencies and civil society. Generalized Extreme Value (GEV and Generalized Pareto Distribution (GPD were applied to investigate the behavior of pollutants in these two regions. Although GEV and GPD are different approaches, they presented similar results. The probability of higher concentrations for CO, NO, NO2, PM10 and PM2.5 was more frequent during the winter, and O3 episodes occur most frequently during summer in the MASP. On the other hand, there is no seasonally defined behavior in MARJ for pollutants, with O3 presenting the shortest return period for high concentrations. In general, Ibirapuera and Campos Elísios stations present the highest probabilities of extreme events with high concentrations in MASP and MARJ, respectively. When the regions are compared, MASP presented higher probabilities of extreme events for all analyzed pollutants, except for NO; while O3 and PM2.5 are those with most frequent probabilities of presenting extreme episodes, in comparison other pollutants. Keywords: Air pollutants, Extreme events, Megacities, Ozone, Particulate matter

The prevalence of resonances among large-a transneptunian objects

Science.gov (United States)

Gladman, Brett; Volk, Kathryn; Van Laerhoven, Christa

2018-04-01

The detached population consists of transneptunian objects (TNOs) with large semi-major axes and sufficiently high perihelia (roughly q>38 au, but there is no simple cut). However, what constitutes 'large semi-major axis' has been, and continues to be, unclear. Once beyond the apehlia of the classical Kuiper Belt (which extends out to about 60 au), objects with semimajor axes from a=60-150 au can be detached, but there are a reasonable number of objects in this range known to be in mean-motion resonances with Neptune. Beyond a=150 au, however, it is a widely-held belief that resonances become `unimportant', and that a q>38 au cut (or sometimes q>50 au) with a>150 au isolates a set of large semimajor axis detached objects. However, once semimajor axes become this large, the orbit determination of the object discovered near perihelion becomes a much harder task then for low-a TNOs. Because small velocity differences near the perihelion of large-a orbits cause large changes the fitted orbital in semimajor axis, extremely good and long baseline astrometry is required to reduce the semimajor axis uncertainty to be smaller than the few tenths of an astronomical unit widths of mean motion resonances. By carefully analyzing the astrometric data of all known large semimajor axis objects, we show that a very large fraction of the objects are in fact likely in high-order mean-motion resonances with Neptune. This prevealence for actually being resonant with Neptune would imply that hypothesized planets are problematic as they would remove the detached objects from these resonances. Instead, we favor a view in which the large-a population is the surviving remnant of a massive early scattering disk, whose surviving members are sculpted mostly by diffusive gravitational interactions with the four giant planets over the last four gigayears, but whose initial emplacement mechanism (in particular: perihelion lifting mechanism) is still unclear but of critical importance to the early

Anders Breivik: Extreme Beliefs Mistaken for Psychosis.

Science.gov (United States)

Rahman, Tahir; Resnick, Phillip J; Harry, Bruce

2016-03-01

The case of Anders Breivik, who committed mass murder in Norway in 2011, stirred controversy among forensic mental health experts. His bizarrely composed compendium and references to himself as the "Knights Templar" raised concerns that he had a psychotic mental illness. Beliefs such as Mr. Breivik's that precede odd, unusual, or extremely violent behavior present a unique challenge to the forensic evaluator, who sometimes struggles to understand those beliefs. Psychotic disorder frequently is invoked to characterize odd, unusual, or extreme beliefs, with a classification that has evolved over time. However, the important concept of overvalued idea, largely ignored in American psychiatry, may better characterize these beliefs in some cases. We discuss the definitions of delusion and overvalued ideas in the context of Anders Breivik's rigidly held extreme beliefs. We also review the British definition of overvalued idea and discuss McHugh's construct, to introduce the term "extreme overvalued belief" as an aid in sharpening the forensic evaluator's conceptualization of these and similar beliefs. © 2016 American Academy of Psychiatry and the Law.

Projecting changes in regional temperature and precipitation extremes in the United States

OpenAIRE

Justin T. Schoof; Scott M. Robeson

2016-01-01

Regional and local climate extremes, and their impacts, result from the multifaceted interplay between large-scale climate forcing, local environmental factors (physiography), and societal vulnerability. In this paper, we review historical and projected changes in temperature and precipitation extremes in the United States, with a focus on strengths and weaknesses of (1) commonly used definitions for extremes such as thresholds and percentiles, (2) statistical approaches to quantifying change...

Exome sequencing for gene discovery in lethal fetal disorders--harnessing the value of extreme phenotypes.

Science.gov (United States)

Filges, Isabel; Friedman, Jan M

2015-10-01

Massively parallel sequencing has revolutionized our understanding of Mendelian disorders, and many novel genes have been discovered to cause disease phenotypes when mutant. At the same time, next-generation sequencing approaches have enabled non-invasive prenatal testing of free fetal DNA in maternal blood. However, little attention has been paid to using whole exome and genome sequencing strategies for gene identification in fetal disorders that are lethal in utero, because they can appear to be sporadic and Mendelian inheritance may be missed. We present challenges and advantages of applying next-generation sequencing approaches to gene discovery in fetal malformation phenotypes and review recent successful discovery approaches. We discuss the implication and significance of recessive inheritance and cross-species phenotyping in fetal lethal conditions. Whole exome sequencing can be used in individual families with undiagnosed lethal congenital anomaly syndromes to discover causal mutations, provided that prior to data analysis, the fetal phenotype can be correlated to a particular developmental pathway in embryogenesis. Cross-species phenotyping allows providing further evidence for causality of discovered variants in genes involved in those extremely rare phenotypes and will increase our knowledge about normal and abnormal human developmental processes. Ultimately, families will benefit from the option of early prenatal diagnosis. © 2014 John Wiley & Sons, Ltd.

Characterization and prediction of extreme events in turbulence

Science.gov (United States)

Fonda, Enrico; Iyer, Kartik P.; Sreenivasan, Katepalli R.

2017-11-01

Extreme events in Nature such as tornadoes, large floods and strong earthquakes are rare but can have devastating consequences. The predictability of these events is very limited at present. Extreme events in turbulence are the very large events in small scales that are intermittent in character. We examine events in energy dissipation rate and enstrophy which are several tens to hundreds to thousands of times the mean value. To this end we use our DNS database of homogeneous and isotropic turbulence with Taylor Reynolds numbers spanning a decade, computed with different small scale resolutions and different box sizes, and study the predictability of these events using machine learning. We start with an aggressive data augmentation to virtually increase the number of these rare events by two orders of magnitude and train a deep convolutional neural network to predict their occurrence in an independent data set. The goal of the work is to explore whether extreme events can be predicted with greater assurance than can be done by conventional methods (e.g., D.A. Donzis & K.R. Sreenivasan, J. Fluid Mech. 647, 13-26, 2010).

A radial velocity survey of extremely hydrogen-deficient stars

International Nuclear Information System (INIS)

Jeffery, C.S.; Kiel Univ.; Drilling, J.S.; Heber, U.

1987-01-01

A radial velocity survey of hot extremely hydrogen-deficient stars has been carried out in order to search for possible binaries. The survey found three stars to have large velocity variations. Of these, two are known hydrogen-deficient binaries and one, HDE 320156 (= LSS 4300), is a suspected binary. HDE 320156 (= LSS 4300) is therefore confirmed to be a single-lined spectroscopic hydrogen-deficient binary. The hydrogen-deficient binary stars all show weak C-lines. The remaining stars in the sample are C-strong extreme-helium (EHe) stars and did not show large-amplitude velocity variations. Small-amplitude radial velocity variations known to be present amongst the EHe stars are largely undetected. Evidence for variability is, however, present in the known variable V2076 Oph (HD 160641) and in LS IV - 1 0 2 with amplitudes between 10 and 20 km s -1 . (author)

Changes in extreme events and the potential impacts on human health.

Science.gov (United States)

Bell, Jesse E; Brown, Claudia Langford; Conlon, Kathryn; Herring, Stephanie; Kunkel, Kenneth E; Lawrimore, Jay; Luber, George; Schreck, Carl; Smith, Adam; Uejio, Christopher

2018-04-01

Extreme weather and climate-related events affect human health by causing death, injury, and illness, as well as having large socioeconomic impacts. Climate change has caused changes in extreme event frequency, intensity, and geographic distribution, and will continue to be a driver for change in the future. Some of these events include heat waves, droughts, wildfires, dust storms, flooding rains, coastal flooding, storm surges, and hurricanes. The pathways connecting extreme events to health outcomes and economic losses can be diverse and complex. The difficulty in predicting these relationships comes from the local societal and environmental factors that affect disease burden. More information is needed about the impacts of climate change on public health and economies to effectively plan for and adapt to climate change. This paper describes some of the ways extreme events are changing and provides examples of the potential impacts on human health and infrastructure. It also identifies key research gaps to be addressed to improve the resilience of public health to extreme events in the future. Extreme weather and climate events affect human health by causing death, injury, and illness, as well as having large socioeconomic impacts. Climate change has caused changes in extreme event frequency, intensity, and geographic distribution, and will continue to be a driver for change in the future. Some of these events include heat waves, droughts, wildfires, flooding rains, coastal flooding, surges, and hurricanes. The pathways connecting extreme events to health outcomes and economic losses can be diverse and complex. The difficulty in predicting these relationships comes from the local societal and environmental factors that affect disease burden.

Did Viking discover life on Mars?

Science.gov (United States)

Klein, H. P.

1999-01-01

A major argument in the claim that life had been discovered during the Viking mission to Mars is that the results obtained in the Labeled Release (LR) experiment are analogous to those observed with terrestrial microorganisms. This assertion is critically examined and found to be implausible.

The discovered preference hypothesis - an empirical test

DEFF Research Database (Denmark)

Lundhede, Thomas; Ladenburg, Jacob; Olsen, Søren Bøye

Using stated preference methods for valuation of non-market goods is known to be vulnerable to a range of biases. Some authors claim that these so-called anomalies in effect render the methods useless for the purpose. However, the Discovered Preference Hypothesis, as put forth by Plott [31], offers...... an nterpretation and explanation of biases which entails that the stated preference methods need not to be completely written off. In this paper we conduct a test for the validity and relevance of the DPH interpretation of biases. In a choice experiment concerning preferences for protection of Danish nature areas...... as respondents evaluate more and more choice sets. This finding supports the Discovered Preference Hypothesis interpretation and explanation of starting point bias....

Changes in Extreme Events and the Potential Impacts on National Security

Science.gov (United States)

Bell, J.

2017-12-01

Extreme weather and climate events affect human health by causing death, injury, and illness, as well as having large socio-economic impacts. Climate change has caused changes in extreme event frequency, intensity and geographic distribution, and will continue to be a driver for changes in the future. Some of the extreme events that have already changed are heat waves, droughts, wildfires, flooding rains, coastal flooding, storm surge, and hurricanes. The pathways connecting extreme events to health outcomes and economic losses can be diverse and complex. The difficulty in predicting these relationships comes from the local intricacies of societal and environmental factors that influences the level of exposure. The goal of this presentation is to discuss the national security implications of changes in extreme weather events and demonstrate how changes in extremes can lead to a host cascading issues. To illustrate this point, this presentation will provide examples of the various pathways that extreme events can increase disease burden and cause economic stress.

GRAMI: Generalized Frequent Subgraph Mining in Large Graphs

KAUST Repository

El Saeedy, Mohammed El Sayed

2011-07-24

Mining frequent subgraphs is an important operation on graphs. Most existing work assumes a database of many small graphs, but modern applications, such as social networks, citation graphs or protein-protein interaction in bioinformatics, are modeled as a single large graph. Interesting interactions in such applications may be transitive (e.g., friend of a friend). Existing methods, however, search for frequent isomorphic (i.e., exact match) subgraphs and cannot discover many useful patterns. In this paper we propose GRAMI, a framework that generalizes frequent subgraph mining in a large single graph. GRAMI discovers frequent patterns. A pattern is a graph where edges are generalized to distance-constrained paths. Depending on the definition of the distance function, many instantiations of the framework are possible. Both directed and undirected graphs, as well as multiple labels per vertex, are supported. We developed an efficient implementation of the framework that models the frequency resolution phase as a constraint satisfaction problem, in order to avoid the costly enumeration of all instances of each pattern in the graph. We also implemented CGRAMI, a version that supports structural and semantic constraints; and AGRAMI, an approximate version that supports very large graphs. Our experiments on real data demonstrate that our framework is up to 3 orders of magnitude faster and discovers more interesting patterns than existing approaches.

Hydrogen at extreme pressures (Review Article)

International Nuclear Information System (INIS)

Goncharov, Alexander F.; Howie, Ross T.; Gregoryanz Eugene

2013-01-01

Here we review recent experimental and theoretical studies of hydrogen approaching metallization regime. Experimental techniques have made great advances over the last several years making it possible to reach previously unachievable conditions of pressure and temperature and to probe hydrogen at these conditions. Theoretical methods have also greatly improved; exemplified through the prediction of new structural and ordered quantum states. Recently, a new solid phase of hydrogen, phase IV, has been discovered in a high-pressure high-temperature domain. This phase is quite unusual structurally and chemically as it represents an intermediate state between common molecular and monatomic configurations. Moreover, it shows remarkable fluxional characteristics related to its quantum nature, which makes it unique among the solid phases, even of light elements. However, phase IV shows the presence of a band gap and exhibits distinct phonon and libron characteristic of classical solids. The quantum behavior of hydrogen in the limit of very high pressure remains an open question. Prospects of studying hydrogen at more extreme conditions by static and combined static-dynamic methods are also presented.

Extreme Simplification and Rendering of Point Sets using Algebraic Multigrid

NARCIS (Netherlands)

Reniers, Dennie; Telea, Alexandru

2005-01-01

We present a novel approach for extreme simplification of point set models in the context of real-time rendering. Point sets are often rendered using simple point primitives, such as oriented discs. However efficient, simple primitives are less effective in approximating large surface areas. A large

On causality of extreme events

Directory of Open Access Journals (Sweden)

Massimiliano Zanin

2016-06-01

Full Text Available Multiple metrics have been developed to detect causality relations between data describing the elements constituting complex systems, all of them considering their evolution through time. Here we propose a metric able to detect causality within static data sets, by analysing how extreme events in one element correspond to the appearance of extreme events in a second one. The metric is able to detect non-linear causalities; to analyse both cross-sectional and longitudinal data sets; and to discriminate between real causalities and correlations caused by confounding factors. We validate the metric through synthetic data, dynamical and chaotic systems, and data representing the human brain activity in a cognitive task. We further show how the proposed metric is able to outperform classical causality metrics, provided non-linear relationships are present and large enough data sets are available.

VARIABILITY OF THE INFRARED EXCESS OF EXTREME DEBRIS DISKS

International Nuclear Information System (INIS)

Meng, Huan Y. A.; Rieke, George H.; Su, Kate Y. L.; Rujopakarn, Wiphu; Ivanov, Valentin D.; Vanzi, Leonardo

2012-01-01

Debris disks with extremely large infrared excesses (fractional luminosities >10 –2 ) are rare. Those with ages between 30 and 130 Myr are of interest because their evolution has progressed well beyond that of protoplanetary disks (which dissipate with a timescale of order 3 Myr), yet they represent a period when dynamical models suggest that terrestrial planet building may still be progressing through large, violent collisions that could yield large amounts of debris and large infrared excesses. For example, our Moon was formed through a violent collision of two large protoplanets during this age range. We report two disks around the solar-like stars ID8 and HD 23514 in this age range where the 24 μm infrared excesses vary on timescales of a few years, even though the stars are not variable in the optical. Variations this rapid are difficult to understand if the debris is produced by collisional cascades, as it is for most debris disks. It is possible that the debris in these two systems arises in part from condensates from silicate-rich vapor produced in a series of violent collisions among relatively large bodies. If their evolution is rapid, the rate of detection of extreme excesses would indicate that major collisions may be relatively common in this age range.

Statistical Entropy of Four-Dimensional Extremal Black Holes

International Nuclear Information System (INIS)

Maldacena, J.M.; Strominger, A.

1996-01-01

String theory is used to count microstates of four-dimensional extremal black holes in compactifications with N=4 and N=8 supersymmetry. The result agrees for large charges with the Bekenstein-Hawking entropy. copyright 1996 The American Physical Society

Vectorlike Leptons at the Large Hadron Collider

Energy Technology Data Exchange (ETDEWEB)

Kumar, Nilanjana [Northern Illinois U.; Martin, Stephen P. [Fermilab

2015-12-22

We study the prospects for excluding or discovering vectorlike leptons using multilepton events at the LHC. We consider models in which the vectorlike leptons decay to tau leptons. If the vectorlike leptons are weak isosinglets, then discovery in multilepton states is found to be extremely challenging. For the case that the vectorlike leptons are weak isodoublet, we argue that there may be an opportunity for exclusion for masses up to about 275 GeV by direct searches with existing LHC data at sqrt{s}=8 TeV. We also discuss prospects for exclusion or discovery at the LHC with future sqrt{s}=13 TeV data.

From Drought to Flood: Biological Responses of Large River Salmonids and Emergent Management Challenges Under California's Extreme Hydroclimatic Variability

Science.gov (United States)

Anderson, C.

2017-12-01

California's hydroclimatic regime is characterized by extreme interannual variability including periodic, multi-year droughts and winter flooding sequences. Statewide, water years 2012-2016 were characterized by extreme drought followed by likely one of the wettest years on record in water year 2017. Similar drought-flood patterns have occurred multiple times both in the contemporary empirical record and reconstructed climate records. Both the extreme magnitude and rapid succession of these hydroclimatic periods pose difficult challenges for water managers and regulatory agencies responsible for providing instream flows to protect and recover threatened and endangered fish species. Principal among these riverine fish species are federally listed winter-run and spring-run Chinook salmon (Oncorhynchus tshawytscha), Central Valley steelhead (Oncorhynchus mykiss), and the pelagic species Delta smelt (Hypomesus transpacificus). Poor instream conditions from 2012-2016 resulted in extremely low abundance estimates and poor overall fish health, and while fish monitoring results from water year 2017 are too preliminary to draw substantive conclusions, early indicators show continued downward population trends despite the historically wet conditions. This poster evaluates California's hydroclimatic conditions over the past decade and quantifies resultant impacts of the 2012-2016 drought and the extremely wet 2017 water year to both adult escapement and juvenile production estimates in California's major inland salmon rivers over that same time span. We will also examine local, state, and federal regulatory actions both in response to the extreme hydroclimatic variability and in preparation for future drought-flood sequences.

Properties of Extreme Precipitation and Their Uncertainties in 3-year GPM Precipitation Radar Data

Science.gov (United States)

Liu, N.; Liu, C.

2017-12-01

Extreme high precipitation rates are often related to flash floods and have devastating impacts on human society and the environments. To better understand these rare events, 3-year Precipitation Features (PFs) are defined by grouping the contiguous areas with nonzero near-surface precipitation derived using Global Precipitation Measurement (GPM) Ku band Precipitation Radar (KuPR). The properties of PFs with extreme precipitation rates greater than 20, 50, 100 mm/hr, such as the geographical distribution, volumetric precipitation contribution, seasonal and diurnal variations, are examined. In addition to the large seasonal and regional variations, the rare extreme precipitation rates often have a larger contribution to the local total precipitation. Extreme precipitation rates occur more often over land than over ocean. The challenges in the retrieval of extreme precipitation might be from the attenuation correction and large uncertainties in the Z-R relationships from near-surface radar reflectivity to precipitation rates. These potential uncertainties are examined by using collocated ground based radar reflectivity and precipitation retrievals.

Prediction of Human Activity by Discovering Temporal Sequence Patterns.

Science.gov (United States)

Li, Kang; Fu, Yun

2014-08-01

Early prediction of ongoing human activity has become more valuable in a large variety of time-critical applications. To build an effective representation for prediction, human activities can be characterized by a complex temporal composition of constituent simple actions and interacting objects. Different from early detection on short-duration simple actions, we propose a novel framework for long -duration complex activity prediction by discovering three key aspects of activity: Causality, Context-cue, and Predictability. The major contributions of our work include: (1) a general framework is proposed to systematically address the problem of complex activity prediction by mining temporal sequence patterns; (2) probabilistic suffix tree (PST) is introduced to model causal relationships between constituent actions, where both large and small order Markov dependencies between action units are captured; (3) the context-cue, especially interactive objects information, is modeled through sequential pattern mining (SPM), where a series of action and object co-occurrence are encoded as a complex symbolic sequence; (4) we also present a predictive accumulative function (PAF) to depict the predictability of each kind of activity. The effectiveness of our approach is evaluated on two experimental scenarios with two data sets for each: action-only prediction and context-aware prediction. Our method achieves superior performance for predicting global activity classes and local action units.

Can doubly strange dibaryon resonances be discovered at RHIC?

International Nuclear Information System (INIS)

Paganis, S. D.; Hoffmann, G. W.; Ray, R. L.; Tang, J.-L.; Udagawa, T.; Longacre, R. S.

2000-01-01

The baryon-baryon continuum invariant mass spectrum generated from relativistic nucleus + nucleus collision data may reveal the existence of doubly strange dibaryons not stable against strong decay if they lie within a few MeV of threshold. Furthermore, since the dominant component of these states is a superposition of two color-octet clusters which can be produced intermediately in a color-deconfined quark-gluon plasma (QGP), an enhanced production of dibaryon resonances could be a signal of QGP formation. A total of eight, doubly strange dibaryon states are considered for experimental search using the STAR detector (solenoidal tracker at RHIC) at the new Relativistic Heavy Ion Collider (RHIC). These states may decay to ΛΛ and/or pΞ - , depending on the resonance energy. STAR's large acceptance, precision tracking and vertex reconstruction capabilities, and large data volume capacity, make it an ideal instrument to use for such a search. Detector performance and analysis sensitivity are studied as a function of resonance production rate and width for one particular dibaryon which can directly strong decay to pΞ - , but not ΛΛ. Results indicate that such resonances may be discovered using STAR if the resonance production rates are comparable to coalescence model predictions for dibaryon bound states. (c) 2000 The American Physical Society

Survival in extreme environments – on the current knowledge of adaptations in tardigrades

DEFF Research Database (Denmark)

Møbjerg, Nadja; Halberg, Kenneth Agerlin; Jørgensen, Aslak

2011-01-01

of mechanisms explaining this phenomenon is lacking. Importantly, recent research has shown that tardigrades even in their active states may be extremely tolerant to environmental stress, handling extreme levels of ionizing radiation, large fluctuation in external salinity and avoiding freezing by supercooling...

The structure and large-scale organization of extreme cold waves over the conterminous United States

Science.gov (United States)

Xie, Zuowei; Black, Robert X.; Deng, Yi

2017-12-01

Extreme cold waves (ECWs) occurring over the conterminous United States (US) are studied through a systematic identification and documentation of their local synoptic structures, associated large-scale meteorological patterns (LMPs), and forcing mechanisms external to the US. Focusing on the boreal cool season (November-March) for 1950‒2005, a hierarchical cluster analysis identifies three ECW patterns, respectively characterized by cold surface air temperature anomalies over the upper midwest (UM), northwestern (NW), and southeastern (SE) US. Locally, ECWs are synoptically organized by anomalous high pressure and northerly flow. At larger scales, the UM LMP features a zonal dipole in the mid-tropospheric height field over North America, while the NW and SE LMPs each include a zonal wave train extending from the North Pacific across North America into the North Atlantic. The Community Climate System Model version 4 (CCSM4) in general simulates the three ECW patterns quite well and successfully reproduces the observed enhancements in the frequency of their associated LMPs. La Niña and the cool phase of the Pacific Decadal Oscillation (PDO) favor the occurrence of NW ECWs, while the warm PDO phase, low Arctic sea ice extent and high Eurasian snow cover extent (SCE) are associated with elevated SE-ECW frequency. Additionally, high Eurasian SCE is linked to increases in the occurrence likelihood of UM ECWs.

The problem of defining contemporary right-wing extremism in political theory

Directory of Open Access Journals (Sweden)

Đorić Marija

2016-01-01

Full Text Available The subject matter of research in this paper is theoretical controversy related to the definition of right-wing extremism. Given the fact that extremism is a variable, amorphous and insufficiently researched phenomenon, largely conditioned by time, space, political and cultural differences, there is a great confusion in the field of political science when defining right-wing extremism. The problem of researching right-wing extremism is additionally complicated by various terms that are being used in the contemporary literature as its synonyms, such as right-wing radicalism, neo-Fascism, ultra-radicalism, etc. In order to provide the most valid theoretical determination of right-wing extremism, the author provides a detailed analysis of all the components constituting this phenomenon and examines their causality. In the political praxis, the term extremism is extensively abused, which additionally complicates its determination. Videlicet, politicians often use term 'extremist' in order to discredit their political opponents. While during the French revolution aristocracy saw the bourgeoisie as extremists, the members of the working class later stated that the bourgeoisie were extremists. The problem lies in the fact that, in politics, extremists are not only the ones who use violence as modus operandi; indeed, it is also used by political opponents who do not belong to the extreme political option. Another aggravating factor in defining right-wing extremism is that many administrative and academic definitions do not make a clear distinction between extremism and related phenomena, such as terrorism, radicalism and populism. Extremism is most often equaled with terrorism, which gives rise to another problem in defining this phenomenon. The relation between extremism and terrorism is the relation of general and specific. Namely, every act of terrorism is concurrently considered to be an act of extremism, but not vice versa, given the fact that

Nuclear structure at high-spin and large-deformation

International Nuclear Information System (INIS)

Shimizu, Yoshifumi R.

2000-01-01

Atomic nucleus is a finite quantal system and shows various marvelous features. One of the purposes of the nuclear structure study is to understand such features from a microscopic viewpoint of nuclear many-body problem. Recently, it is becoming possible to explore nuclear states under 'extreme conditions', which are far different from the usual ground states of stable nuclei, and new aspects of such unstable nuclei attract our interests. In this lecture, I would like to discuss the nuclear structure in the limit of rapid rotation, or the extreme states with very large angular momenta, which became accessible by recent advent of large arrays of gamma-ray detecting system; these devices are extremely useful to measure coincident multiple γ-rays following heavy-ion fusion reactions. Including such experimental aspects as how to detect the nuclear rotational states, I review physics of high-spin states starting from the elementary subjects of nuclear structure study. In would like also to discuss the extreme states with very large nuclear deformation, which are easily realized in rapidly rotating nuclei. (author)

FIRST PHOTOMETRIC INVESTIGATION OF THE NEWLY DISCOVERED W UMa-TYPE BINARY STAR MR Com

Energy Technology Data Exchange (ETDEWEB)

Qian, S.-B.; Liu, N.-P.; Liao, W.-P.; He, J.-J.; Liu, L.; Zhu, L.-Y.; Wang, J.-J.; Zhao, E.-G., E-mail: qsb@ynao.ac.cn [Yunnan Observatories, Chinese Academy of Sciences (CAS), P.O. Box 110, 650011 Kunming (China)

2013-08-01

By analyzing multi-color light curves of the newly discovered W UMa-type binary, MR Com, we discovered that it is a shallow-contact binary with a degree of contact factor of f = 10.0% {+-} 2.1%. Photometric solutions reveal that MR Com is a W-type system with a mass ratio of q = 3.9 where the less massive component is about 90 K hotter than the more massive one. By investigating all of the available times of minimum light, we found that the general trend of the Observed-Calculated (O - C) curve shows a downward parabolic variation while it undergoes a cyclic variation with a small amplitude of 0.0031 days and a period of 10.1 yr. The downward parabolic change corresponds to a long-term decrease in the orbital period at a rate of P-dot = -5.3 x 10{sup -7} days yr{sup -1} that may be caused by a combination of a mass transfer and an angular momentum loss (AML) via magnetic braking. Among the 16 shallow-contact systems with a decreasing orbital period, MR Com has the lowest mass ratio (e.g., 1/q = 0.26). The shallow-contact configuration, the low-mass ratio, and the long-term period decrease all suggest that systems similar to MR Com are on the AML-controlled stage of the evolutionary scheme proposed by Qian. They will oscillate around a critical mass ratio and evolve into a deep contact with a higher mass ratio. The small-amplitude cyclic change in the O - C curve was analyzed for the light-travel time effect via the presence of an extremely cool stellar companion.

Early neurodevelopmental outcomes of extremely preterm infants.

Science.gov (United States)

Rogers, Elizabeth E; Hintz, Susan R

2016-12-01

Infants born at extreme preterm gestation are at risk for both death and disability. Although rates of survival have improved for this population, and some evidence suggests a trend toward decreased neuromotor impairment over the past decades, a significant improvement in overall early neurodevelopmental outcome has not yet been realized. This review will examine the rates and types of neurodevelopmental impairment seen after extremely preterm birth, including neurosensory, motor, cognitive, and behavioral outcomes. We focus on early outcomes in the first 18-36 months of life, as the majority of large neonatal studies examining neurodevelopmental outcomes stop at this age. However, this early age is clearly just a first glimpse into lifetime outcomes; the neurodevelopmental effects of extreme prematurity may last through school age, adolescence, and beyond. Importantly, prematurity appears to be an independent risk factor for adverse development, but this population demonstrates considerable variability in the types and severity of impairments. Understanding both the nature and prevalence of neurodevelopmental impairment among extremely preterm infants is important because it can lead to targeted interventions that in turn may lead to improved outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

Understanding extreme sea levels for coastal impact and adaptation analysis

Science.gov (United States)

Wahl, T.; Haigh, I. D.; Nicholls, R. J.; Arns, A.; Hinkel, J.; Dangendorf, S.; Slangen, A.

2016-12-01

Coastal impact and adaptation assessments require detailed knowledge on extreme sea levels, because increasing damage due to extreme events, such as storm surges and tropical cyclones, is one of the major consequences of sea level rise and climate change. In fact, the IPCC has highlighted in its AR4 report that "societal impacts of sea level change primarily occur via the extreme levels rather than as a direct consequence of mean sea level changes". Over the last few decades, substantial research efforts have been directed towards improved understanding of past and future mean sea level; different scenarios were developed with process-based or semi-empirical models and used for coastal impact assessments at various spatial scales to guide coastal management and adaptation efforts. The uncertainties in future sea level rise are typically accounted for by analyzing the impacts associated with a range of scenarios leading to a vertical displacement of the distribution of extreme sea-levels. And indeed most regional and global studies find little or no evidence for changes in storminess with climate change, although there is still low confidence in the results. However, and much more importantly, there is still a limited understanding of present-day extreme sea-levels which is largely ignored in most impact and adaptation analyses. The two key uncertainties stem from: (1) numerical models that are used to generate long time series of extreme sea-levels. The bias of these models varies spatially and can reach values much larger than the expected sea level rise; but it can be accounted for in most regions making use of in-situ measurements; (2) Statistical models used for determining present-day extreme sea-level exceedance probabilities. There is no universally accepted approach to obtain such values for flood risk assessments and while substantial research has explored inter-model uncertainties for mean sea level, we explore here, for the first time, inter

Mandelbrot's Extremism

NARCIS (Netherlands)

Beirlant, J.; Schoutens, W.; Segers, J.J.J.

2004-01-01

In the sixties Mandelbrot already showed that extreme price swings are more likely than some of us think or incorporate in our models.A modern toolbox for analyzing such rare events can be found in the field of extreme value theory.At the core of extreme value theory lies the modelling of maxima

Kinematic and neuromuscular relationships between lower extremity clinical movement assessments.

Science.gov (United States)

Mauntel, Timothy C; Cram, Tyler R; Frank, Barnett S; Begalle, Rebecca L; Norcross, Marc F; Blackburn, J Troy; Padua, Darin A

2018-06-01

Lower extremity injuries have immediate and long-term consequences. Lower extremity movement assessments can assist with identifying individuals at greater injury risk and guide injury prevention interventions. Movement assessments identify similar movement characteristics and evidence suggests large magnitude kinematic relationships exist between movement patterns observed across assessments; however, the magnitude of the relationships for electromyographic (EMG) measures across movement assessments remains largely unknown. This study examined relationships between lower extremity kinematic and EMG measures during jump landings and single leg squats. Lower extremity three-dimensional kinematic and EMG data were sampled from healthy adults (males = 20, females = 20) during the movement assessments. Pearson correlations examined the relationships of the kinematic and EMG measures and paired samples t-tests compared mean kinematic and EMG measures between the assessments. Overall, significant moderate correlations were observed for lower extremity kinematic (r avg  = 0.41, r range  = 0.10-0.61) and EMG (r avg  = 0.47, r range  = 0.32-0.80) measures across assessments. Kinematic and EMG measures were greater during the jump landings. Jump landings and single leg squats place different demands on the body and necessitate different kinematic and EMG patterns, such that these measures are not highly correlated between assessments. Clinicians should, therefore, use multiple assessments to identify aberrant movement and neuromuscular control patterns so that comprehensive interventions can be implemented.

Design of a prototype position actuator for the primary mirror segments of the European Extremely Large Telescope

Science.gov (United States)

Jiménez, A.; Morante, E.; Viera, T.; Núñez, M.; Reyes, M.

2010-07-01

European Extremely Large Telescope (E-ELT) based in 984 primary mirror segments achieving required optical performance; they must position relatively to adjacent segments with relative nanometer accuracy. CESA designed M1 Position Actuators (PACT) to comply with demanding performance requirements of EELT. Three PACT are located under each segment controlling three out of the plane degrees of freedom (tip, tilt, piston). To achieve a high linear accuracy in long operational displacements, PACT uses two stages in series. First stage based on Voice Coil Actuator (VCA) to achieve high accuracies in very short travel ranges, while second stage based on Brushless DC Motor (BLDC) provides large stroke ranges and allows positioning the first stage closer to the demanded position. A BLDC motor is used achieving a continuous smoothly movement compared to sudden jumps of a stepper. A gear box attached to the motor allows a high reduction of power consumption and provides a great challenge for sizing. PACT space envelope was reduced by means of two flat springs fixed to VCA. Its main characteristic is a low linear axial stiffness. To achieve best performance for PACT, sensors have been included in both stages. A rotary encoder is included in BLDC stage to close position/velocity control loop. An incremental optical encoder measures PACT travel range with relative nanometer accuracy and used to close the position loop of the whole actuator movement. For this purpose, four different optical sensors with different gratings will be evaluated. Control strategy show different internal closed loops that work together to achieve required performance.

Combinations of large-scale circulation anomalies conducive to precipitation extremes in the Czech Republic

Czech Academy of Sciences Publication Activity Database

Kašpar, Marek; Müller, Miloslav

2014-01-01

Roč. 138, March 2014 (2014), s. 205-212 ISSN 0169-8095 R&D Projects: GA ČR(CZ) GAP209/11/1990 Institutional support: RVO:68378289 Keywords : precipitation extreme * synoptic-scale cause * re-analysis * circulation anomaly Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 2.844, year: 2014 http://www.sciencedirect.com/science/article/pii/S0169809513003372

Non-Gaussian statistics of extreme events in stimulated Raman scattering: The role of coherent memory and source noise

Science.gov (United States)

Monfared, Yashar E.; Ponomarenko, Sergey A.

2017-10-01

We explore theoretically and numerically extreme event excitation in stimulated Raman scattering in gases. We consider gas-filled hollow-core photonic crystal fibers as a particular system realization. We show that moderate amplitude pump fluctuations obeying Gaussian statistics lead to the emergence of heavy-tailed non-Gaussian statistics as coherent seed Stokes pulses are amplified on propagation along the fiber. We reveal the crucial role that coherent memory effects play in causing non-Gaussian statistics of the system. We discover that extreme events can occur even at the initial stage of stimulated Raman scattering when one can neglect energy depletion of an intense, strongly fluctuating Gaussian pump source. Our analytical results in the undepleted pump approximation explicitly illustrate power-law probability density generation as the input pump noise is transferred to the output Stokes pulses.

Pushing the Envelope of Extreme Space Weather

Science.gov (United States)

Pesnell, W. D.

2014-12-01

Extreme Space Weather events are large solar flares or geomagnetic storms, which can cost billions of dollars to recover from. We have few examples of such events; the Carrington Event (the solar superstorm) is one of the few that had superlatives in three categories: size of solar flare, drop in Dst, and amplitude of aa. Kepler observations show that stars similar to the Sun can have flares releasing millions of times more energy than an X-class flare. These flares and the accompanying coronal mass ejections could strongly affect the atmosphere surrounding a planet. What level of solar activity would be necessary to strongly affect the atmosphere of the Earth? Can we map out the envelope of space weather along the evolution of the Sun? What would space weather look like if the Sun stopped producing a magnetic field? To what extreme should Space Weather go? These are the extremes of Space Weather explored in this talk.

A case series of clinically undiagnosed hematopoietic neoplasms discovered at autopsy.

Science.gov (United States)

Podduturi, Varsha; Guileyardo, Joseph M; Soto, Luis R; Krause, John R

2015-06-01

In the United States, autopsy rates have diminished to less than 5% during the last half of the 20th century and the beginning of the 21st century for a multitude of reasons. Many believe this results in unrecognized malignancies that could have explained a patient's death. We describe six deaths in which hematopoietic neoplasms were identified at autopsy but were not diagnosed clinically. The six undiagnosed hematopoietic malignancy cases discovered at autopsy include four men and two women ranging from 50 to 78 years of age. One patient was African American and five patients were white, all with multiple comorbidities. The tumors included diffuse large B-cell lymphoma, activated B-cell type, intravascular large B-cell lymphoma, ALK-negative anaplastic large cell lymphoma arising in a setting of human immunodeficiency virus, and a myeloid sarcoma. These cases illustrate the importance of the traditional postmortem examination in not only confirming clinical diagnoses but also identifying previously unknown diagnoses. Hematologic malignancies may present with nonspecific clinical manifestations, and this series of cases also emphasizes the necessity for widening the differential diagnosis in patients with unexplained lactic acidosis and hepatic failure to include hematopoietic malignancies since prompt treatment may be lifesaving. Copyright© by the American Society for Clinical Pathology.

Discovering English with the Sketch Engine

Science.gov (United States)

Thomas, James

2014-01-01

"Discovering English with the Sketch Engine" is the title of a new book (Thomas, 2014) which introduces the use of corpora in language study, teaching, writing and translating. It focuses on using the Sketch Engine to identify patterns of normal usage in many aspects of English ranging from morphology to discourse and pragmatics. This…

What if Fleming had not discovered penicillin?

Science.gov (United States)

Alharbi, Sulaiman Ali; Wainwright, Milton; Alahmadi, Tahani Awad; Salleeh, Hashim Bin; Faden, Asmaa A; Chinnathambi, Arunachalam

2014-09-01

What would have happened had Alexander Fleming not discovered penicillin in 1928? Perhaps the obvious answer is that, someone else would have discovered penicillin during 1930s and the Oxford group, would still have purified it sometime in the early 1940s. Here, however, in this counterfactual account of the penicillin story, it is argued that without Fleming, penicillin might still be undiscovered and the antibiotic age would never have dawned. As a result, many of the recent developments in medicine, such as organ transplantation, might have been delayed or, at best, made more hazardous. Penicillin might have come onto the scene a few years later but, had Fleming overlooked the discovery, it seems certain that penicillin would not have saved countless Allied lives, during and after D-Day. Instead of having enjoyed fifty and more years of the antibiotic age, it is argued here, that we would have had to rely upon highly developed sulphonamides, so-called "supasulfas", and other chemically-derived antibacterial drugs. Indeed, it might be the case that, even well into this new millennium, the antibiotic age has yet to dawn, and medicine is still waiting for someone to chance upon penicillin. Here we discuss what might have happened had Fleming not discovered penicillin and come to the conclusion that the medical armoury available today would have been far different and might have relied solely upon highly developed varieties of sulphonamides or similar, synthetic, non-antibiotic antibacterial agents.

The Universe for all to discover

Science.gov (United States)

Ortiz-Gil, A.; Ballesteros, F.; Espinós, H.; Fernández-Soto, A.; Lanzara, M.; Moya, M. J.; Navarro, J.

2015-05-01

In the title of this paper, we have changed the slogan of the International Year of Astronomy, ``The Universe yours to discover" to ``The Universe for all to discover" in order to emphasize the need to think about broader audiences when we plan astronomical activities at school or during outreach events. The strategy we propose follows what is known as the Universal Design for Learning (UDL). UDL allows to reach to the general public as well as to audiences which might be regarded as ``special" because they have some disability. It has been shown that everybody has a preferred style of learning (some remember better what they see, others what they hear or what they touch) and therefore, everybody is more or less able under the different styles of learning. Through this talk I am going to outline some of the principles of the UDL that can be applied in the teaching and communication of Astronomy, along with an example of its implementation in the project ``A Touch of the Universe".

Discovering context-aware conditional functional dependencies

Institute of Scientific and Technical Information of China (English)

Yuefeng DU; Derong SHEN; Tiezheng NIE; Yue KOU; Ge YU

2017-01-01

Conditional functional dependencies(CFDs) are important techniques for data consistency.However,CFDs are limited to 1) provide the reasonable values for consistency repairing and 2) detect potential errors.This paper presents context-aware conditional functional dependencies(CCFDs) which contribute to provide reasonable values and detect potential errors.Especially,we focus on automatically discovering minimal CCFDs.In this paper,we present context relativity to measure the relationship of CFDs.The overlap of the related CFDs can provide reasonable values which result in more accuracy consistency repairing,and some related CFDs are combined into CCFDs.Moreover,we prove that discovering minimal CCFDs is NP-complete and we design the precise method and the heuristic method.We also present the dominating value to facilitate the process in both the precise method and the heuristic method.Additionally,the context relativity of the CFDs affects the cleaning results.We will give an approximate threshold of context relativity according to data distribution for suggestion.The repairing results are approved more accuracy,even evidenced by our empirical evaluation.

A knowledge-based integrated approach for discovering and repairing declare maps

NARCIS (Netherlands)

Maggi, F.M.; Jagadeesh Chandra Bose, R.P.; Aalst, van der W.M.P.; Salinesi, C.; Norrie, M.C.; Pastor, O.

2013-01-01

Process mining techniques can be used to discover process models from event data. Often the resulting models are complex due to the variability of the underlying process. Therefore, we aim at discovering declarative process models that can deal with such variability. However, for real-life event

Detecting impacts of extreme events with ecological in situ monitoring networks

Directory of Open Access Journals (Sweden)

M. D. Mahecha

2017-09-01

Full Text Available Extreme hydrometeorological conditions typically impact ecophysiological processes on land. Satellite-based observations of the terrestrial biosphere provide an important reference for detecting and describing the spatiotemporal development of such events. However, in-depth investigations of ecological processes during extreme events require additional in situ observations. The question is whether the density of existing ecological in situ networks is sufficient for analysing the impact of extreme events, and what are expected event detection rates of ecological in situ networks of a given size. To assess these issues, we build a baseline of extreme reductions in the fraction of absorbed photosynthetically active radiation (FAPAR, identified by a new event detection method tailored to identify extremes of regional relevance. We then investigate the event detection success rates of hypothetical networks of varying sizes. Our results show that large extremes can be reliably detected with relatively small networks, but also reveal a linear decay of detection probabilities towards smaller extreme events in log–log space. For instance, networks with  ≈  100 randomly placed sites in Europe yield a  ≥  90 % chance of detecting the eight largest (typically very large extreme events; but only a  ≥  50 % chance of capturing the 39 largest events. These findings are consistent with probability-theoretic considerations, but the slopes of the decay rates deviate due to temporal autocorrelation and the exact implementation of the extreme event detection algorithm. Using the examples of AmeriFlux and NEON, we then investigate to what degree ecological in situ networks can capture extreme events of a given size. Consistent with our theoretical considerations, we find that today's systematically designed networks (i.e. NEON reliably detect the largest extremes, but that the extreme event detection rates are not higher than would

Decision Mining Revisited – Discovering Overlapping Rules

NARCIS (Netherlands)

Mannhardt, F.; de Leoni, M.; Reijers, H.A.; van der Aalst, W.M.P.

2016-01-01

Decision mining enriches process models with rules underlying decisions in processes using historical process execution data. Choices between multiple activities are specified through rules defined over process data. Existing decision mining methods focus on discovering mutually-exclusive rules,

Transpressive mantle uplift at large offset oceanic transform faults

Science.gov (United States)

Maia, M.; Briais, A.; Brunelli, D.; Ligi, M.; Sichel, S. E.; Campos, T.

2017-12-01

Large-offset transform faults deform due to changes in plate motions and local processes. At the St. Paul transform, in the Equatorial Atlantic, a large body of ultramafic rocks composed of variably serpentinized and mylonitized peridotites is presently being tectonically uplifted. We recently discovered that the origin of the regional mantle uplift is linked to long-standing compressive stresses along the transform fault (1). A positive flower structure, mainly made of mylonitized mantle rocks, can be recognized on the 200 km large push-up ridge. Compressive earthquakes mechanisms reveal seismically active thrust faults on the southern flank of the ridge . The regional transpressive stress field affects a large portion of the ridge segment south of the transform, as revealed by the presence of faults and dykes striking obliquely to the direction of the central ridge axis. A smaller thrust, affecting recent sediments, was mapped south of this segment, suggesting a regional active compressive stress field. The transpressive stress field is interpreted to derive from the propagation of the Mid-Atlantic Ridge (MAR) segment into the transform domain as a response to the enhanced melt supply at the ridge axis. The propagation forced the migration and segmentation of the transform fault southward and the formation of restraining step-overs. The process started after a counterclockwise change in plate motion at 11 Ma initially resulting in extensive stress of the transform domain. A flexural transverse ridge formed in response. Shortly after plate reorganization, the MAR segment started to propagate southwards due to the interaction of the ridge and the Sierra Leone thermal anomaly. 1- Maia et al., 2016. Extreme mantle uplift and exhumation along a transpressive transform fault Nat. Geo. doi:10.1038/ngeo2759

How extreme is extreme hourly precipitation?

Science.gov (United States)

Papalexiou, Simon Michael; Dialynas, Yannis G.; Pappas, Christoforos

2016-04-01

The importance of accurate representation of precipitation at fine time scales (e.g., hourly), directly associated with flash flood events, is crucial in hydrological design and prediction. The upper part of a probability distribution, known as the distribution tail, determines the behavior of extreme events. In general, and loosely speaking, tails can be categorized in two families: the subexponential and the hyperexponential family, with the first generating more intense and more frequent extremes compared to the latter. In past studies, the focus has been mainly on daily precipitation, with the Gamma distribution being the most popular model. Here, we investigate the behaviour of tails of hourly precipitation by comparing the upper part of empirical distributions of thousands of records with three general types of tails corresponding to the Pareto, Lognormal, and Weibull distributions. Specifically, we use thousands of hourly rainfall records from all over the USA. The analysis indicates that heavier-tailed distributions describe better the observed hourly rainfall extremes in comparison to lighter tails. Traditional representations of the marginal distribution of hourly rainfall may significantly deviate from observed behaviours of extremes, with direct implications on hydroclimatic variables modelling and engineering design.

Attribution of extreme rainfall from Hurricane Harvey, August 2017

OpenAIRE

Van Oldenborgh, Geert Jan; Van Der Wiel, Karin; Sebastian, A.G.; Singh, Roop; Arrighi, Julie; Otto, Friederike; Haustein, Karsten; Li, Sihan; Vecchi, Gabriel; Cullen, Heidi

2017-01-01

During August 25-30, 2017, Hurricane Harvey stalled over Texas and caused extreme precipitation, particularly over Houston and the surrounding area on August 26-28. This resulted in extensive flooding with over 80 fatalities and large economic costs. It was an extremely rare event: the return period of the highest observed three-day precipitation amount, 1043.4 mm 3dy-1 at Baytown, is more than 9000 years (97.5% one-sided confidence interval) and return periods exceeded 1000 yr (750 mm 3dy-1)...

Single-step ethanol production from lignocellulose using novel extremely thermophilic bacteria.

Science.gov (United States)

Svetlitchnyi, Vitali A; Kensch, Oliver; Falkenhan, Doris A; Korseska, Svenja G; Lippert, Nadine; Prinz, Melanie; Sassi, Jamaleddine; Schickor, Anke; Curvers, Simon

2013-02-28

Consolidated bioprocessing (CBP) of lignocellulosic biomass to ethanol using thermophilic bacteria provides a promising solution for efficient lignocellulose conversion without the need for additional cellulolytic enzymes. Most studies on the thermophilic CBP concentrate on co-cultivation of the thermophilic cellulolytic bacterium Clostridium thermocellum with non-cellulolytic thermophilic anaerobes at temperatures of 55°C-60°C. We have specifically screened for cellulolytic bacteria growing at temperatures >70°C to enable direct conversion of lignocellulosic materials into ethanol. Seven new strains of extremely thermophilic anaerobic cellulolytic bacteria of the genus Caldicellulosiruptor and eight new strains of extremely thermophilic xylanolytic/saccharolytic bacteria of the genus Thermoanaerobacter isolated from environmental samples exhibited fast growth at 72°C, extensive lignocellulose degradation and high yield ethanol production on cellulose and pretreated lignocellulosic biomass. Monocultures of Caldicellulosiruptor strains degraded up to 89-97% of the cellulose and hemicellulose polymers in pretreated biomass and produced up to 72 mM ethanol on cellulose without addition of exogenous enzymes. In dual co-cultures of Caldicellulosiruptor strains with Thermoanaerobacter strains the ethanol concentrations rose 2- to 8.2-fold compared to cellulolytic monocultures. A co-culture of Caldicellulosiruptor DIB 087C and Thermoanaerobacter DIB 097X was particularly effective in the conversion of cellulose to ethanol, ethanol comprising 34.8 mol% of the total organic products. In contrast, a co-culture of Caldicellulosiruptor saccharolyticus DSM 8903 and Thermoanaerobacter mathranii subsp. mathranii DSM 11426 produced only low amounts of ethanol. The newly discovered Caldicellulosiruptor sp. strain DIB 004C was capable of producing unexpectedly large amounts of ethanol from lignocellulose in fermentors. The established co-cultures of new Caldicellulosiruptor

Clinical application of lower extremity CTA and lower extremity perfusion CT as a method of diagnostic for lower extremity atherosclerotic obliterans

Energy Technology Data Exchange (ETDEWEB)

Moon, Il Bong; Dong, Kyung Rae [Dept. Radiological Technology, Gwangju Health University, Gwangju (Korea, Republic of); Goo, Eun Hoe [Dept. Radiological Science, Cheongju University, Cheongju (Korea, Republic of)

2016-11-15

The purpose of this study was to assess clinical application of lower extremity CTA and lower extremity perfusion CT as a method of diagnostic for lower extremity atherosclerotic obliterans. From January to July 2016, 30 patients (mean age, 68) were studied with lower extremity CTA and lower extremity perfusion CT. 128 channel multi-detector row CT scans were acquired with a CT scanner (SOMATOM Definition Flash, Siemens medical solution, Germany) of lower extremity perfusion CT and lower extremity CTA. Acquired images were reconstructed with 3D workstation (Leonardo, Siemens, Germany). Site of lower extremity arterial occlusive and stenosis lesions were detected superficial femoral artery 36.6%, popliteal artery 23.4%, external iliac artery 16.7%, common femoral artery 13.3%, peroneal artery 10%. The mean total DLP comparison of lower extremity perfusion CT and lower extremity CTA, 650 mGy-cm and 675 mGy-cm, respectively. Lower extremity perfusion CT and lower extremity CTA were realized that were never be two examination that were exactly the same legions. Future through the development of lower extremity perfusion CT soft ware programs suggest possible clinical applications.

Saturated Overburden Scattering and the Multiscatter Frontier: Discovering Dark Matter at the Planck Mass and Beyond

OpenAIRE

Bramante, Joseph; Broerman, Benjamin; Lang, Rafael F.; Raj, Nirmal

2018-01-01

We show that underground experiments like LUX/LZ, PandaX-II, XENON, and PICO could discover dark matter up to the Planck mass and beyond, with new searches for dark matter that scatters multiple times in these detectors. This opens up significant discovery potential via re-analysis of existing and future data. We also identify a new effect which substantially enhances experimental sensitivity to large dark matter scattering cross-sections: while passing through atmospheric or solid overburden...

Thermodynamics of extremal rotating thin shells in an extremal BTZ spacetime and the extremal black hole entropy

Science.gov (United States)

Lemos, José P. S.; Minamitsuji, Masato; Zaslavskii, Oleg B.

2017-02-01

In a (2 +1 )-dimensional spacetime with a negative cosmological constant, the thermodynamics and the entropy of an extremal rotating thin shell, i.e., an extremal rotating ring, are investigated. The outer and inner regions with respect to the shell are taken to be the Bañados-Teitelbom-Zanelli (BTZ) spacetime and the vacuum ground state anti-de Sitter spacetime, respectively. By applying the first law of thermodynamics to the extremal thin shell, one shows that the entropy of the shell is an arbitrary well-behaved function of the gravitational area A+ alone, S =S (A+). When the thin shell approaches its own gravitational radius r+ and turns into an extremal rotating BTZ black hole, it is found that the entropy of the spacetime remains such a function of A+, both when the local temperature of the shell at the gravitational radius is zero and nonzero. It is thus vindicated by this analysis that extremal black holes, here extremal BTZ black holes, have different properties from the corresponding nonextremal black holes, which have a definite entropy, the Bekenstein-Hawking entropy S (A+)=A/+4G , where G is the gravitational constant. It is argued that for extremal black holes, in particular for extremal BTZ black holes, one should set 0 ≤S (A+)≤A/+4G;i.e., the extremal black hole entropy has values in between zero and the maximum Bekenstein-Hawking entropy A/+4 G . Thus, rather than having just two entropies for extremal black holes, as previous results have debated, namely, 0 and A/+4 G , it is shown here that extremal black holes, in particular extremal BTZ black holes, may have a continuous range of entropies, limited by precisely those two entropies. Surely, the entropy that a particular extremal black hole picks must depend on past processes, notably on how it was formed. A remarkable relation between the third law of thermodynamics and the impossibility for a massive body to reach the velocity of light is also found. In addition, in the procedure, it

Discovering Science through Art-Based Activities

Science.gov (United States)

Alberts, Rebecca

2010-01-01

Art and science are intrinsically linked; the essence of art and science is discovery. Both artists and scientists work in a systematic but creative way--knowledge and understanding are built up through pieces of art or a series of labs. In the classroom, integrating science and visual art can provide students with the latitude to think, discover,…

Inclined Zenith Aurora over Kyoto on 17 September 1770: Graphical Evidence of Extreme Magnetic Storm

Science.gov (United States)

Kataoka, Ryuho; Iwahashi, Kiyomi

2017-10-01

Red auroras were observed in Japan during an extreme magnetic storm that occurred on 17 September 1770. We show new evidence that the red aurora extended toward the zenith of Kyoto around midnight. The basic appearance of the historical painting of the red aurora is geometrically reproduced based on the inclination of the local magnetic field and a detailed description in a newly discovered diary. The presence of the inclined zenith aurora over Kyoto suggests that the intensity of the September 1770 magnetic storm is comparable to, or slightly larger than that of the September 1859 Carrington storm.

Operational early warning platform for extreme meteorological events

Science.gov (United States)

Mühr, Bernhard; Kunz, Michael

2015-04-01

Operational early warning platform for extreme meteorological events Most natural disasters are related to extreme weather events (e.g. typhoons); weather conditions, however, are also highly relevant for humanitarian and disaster relief operations during and after other natural disaster like earthquakes. The internet service "Wettergefahren-Frühwarnung" (WF) provides various information on extreme weather events, especially when these events are associated with a high potential for large damage. The main focus of the platform is on Central Europe, but major events are also monitored worldwide on a daily routine. WF provides high-resolution forecast maps for many weather parameters which allow detailed and reliable predictions about weather conditions during the next days in the affected areas. The WF service became operational in February 2004 and is part of the Center for Disaster Management and Risk Reduction Technology (CEDIM) since 2007. At the end of 2011, CEDIM embarked a new type of interdisciplinary disaster research termed as forensic disaster analysis (FDA) in near real time. In case of an imminent extreme weather event WF plays an important role in CEDIM's FDA group. It provides early and precise information which are always available and updated several times during a day and gives advice and assists with articles and reports on extreme events.

Soft tissue masses of extremities: MR findings

Energy Technology Data Exchange (ETDEWEB)

Son, Seok Hyun; Yang, Seoung Oh; Choi, Jong Chul; Park, Byeong Ho; Lee, Ki Nam; Choi, Sun Seob; Chung, Duck Hwan [Dong-A University College of Medicine, Pusan (Korea, Republic of)

1993-11-15

To evaluate MR findings of soft tissue masses in extremities and to find the helpful findings of distinguish benignity from malignancy, 28 soft tissue masses (22 benign and 6 malignant) in extremities were reviewed. TI-weighted, proton density, T2-weighted and Gd-DTPA enhanced images were obtained. MR images allowed a specific diagnosis in large number of benign masses, such as hemangioma(8/9), lipoma(2/2), angiolipoma(1/1), epidermoid cyst(2/2), myositis ossificans(1/1), synovial chondromatosis(1/1) and pigmented villonodular synovitis(1/2). Specific diagnosis was difficult in the rest of the masses including malignancy. However, inhomogeneous signal intensities with necrosis and inhomogeneous enhancement may suggest malignant masses.

Distance correlation methods for discovering associations in large astrophysical databases

International Nuclear Information System (INIS)

Martínez-Gómez, Elizabeth; Richards, Mercedes T.; Richards, Donald St. P.

2014-01-01

High-dimensional, large-sample astrophysical databases of galaxy clusters, such as the Chandra Deep Field South COMBO-17 database, provide measurements on many variables for thousands of galaxies and a range of redshifts. Current understanding of galaxy formation and evolution rests sensitively on relationships between different astrophysical variables; hence an ability to detect and verify associations or correlations between variables is important in astrophysical research. In this paper, we apply a recently defined statistical measure called the distance correlation coefficient, which can be used to identify new associations and correlations between astrophysical variables. The distance correlation coefficient applies to variables of any dimension, can be used to determine smaller sets of variables that provide equivalent astrophysical information, is zero only when variables are independent, and is capable of detecting nonlinear associations that are undetectable by the classical Pearson correlation coefficient. Hence, the distance correlation coefficient provides more information than the Pearson coefficient. We analyze numerous pairs of variables in the COMBO-17 database with the distance correlation method and with the maximal information coefficient. We show that the Pearson coefficient can be estimated with higher accuracy from the corresponding distance correlation coefficient than from the maximal information coefficient. For given values of the Pearson coefficient, the distance correlation method has a greater ability than the maximal information coefficient to resolve astrophysical data into highly concentrated horseshoe- or V-shapes, which enhances classification and pattern identification. These results are observed over a range of redshifts beyond the local universe and for galaxies from elliptical to spiral.

Possible origin of Saturn's newly discovered outer ring

International Nuclear Information System (INIS)

Moehlmann, D.

1986-01-01

Within a planetogonic model the self-gravitationally caused formation of pre-planetary and pre-satellite rings from an earlier thin disk is reported. The theoretically derived orbital radii of these rings are compared with the orbital levels in the planetary system and the satellite systems of Jupiter, Saturn and Uranus. From this comparison it is concluded that at the radial position of Saturn's newly discovered outer ring an early pre-satellite ring of more or less evolved satellites could have existed. These satellites should have been disturbed in their evolution by the gravitation of the neighbouring massive satellite Titan. The comparison also may indicate similarities between the asteroidal belt and the newly discovered outer ring of Saturn

Neoadjuvant Interdigitated Chemoradiotherapy Using Mesna, Doxorubicin, and Ifosfamide for Large, High-grade, Soft Tissue Sarcomas of the Extremity: Improved Efficacy and Reduced Toxicity.

Science.gov (United States)

Chowdhary, Mudit; Sen, Neilayan; Jeans, Elizabeth B; Miller, Luke; Batus, Marta; Gitelis, Steven; Wang, Dian; Abrams, Ross A

2018-05-18

Patients with large, high-grade extremity soft tissue sarcoma (STS) are at high risk for both local and distant recurrence. RTOG 95-14, using a regimen of neoadjuvant interdigitated chemoradiotherapy with mesna, doxorubicin, ifosfamide, and dacarbazine followed by surgery and 3 cycles of adjuvant mesna, doxorubicin, ifosfamide, and dacarbazine, demonstrated high rates of disease control at the cost of significant toxicity (83% grade 4, 5% grade 5). As such, this regimen has not been widely adopted. Herein, we report our institutional outcomes utilizing a modified interdigitated chemoradiotherapy regimen, without dacarbazine, and current radiotherapy planning and delivery techniques for high-risk STS. Adults with large (≥5 cm; median, 12.9 cm), grade 3 extremity STS who were prospectively treated as part of our institutional standard of care from 2008 to 2016 are included. Neoadjuvant chemoradiotherapy consisted of 3 cycles of mesna, doxorubicin, and ifosfamide (MAI) and 44 Gy (22 Gy in 11 fractions between cycles of MAI) after which patients underwent surgical resection and received 3 additional cycles of MAI. Twenty-six patients received the MAI treatment protocol. At a median follow-up of 47.3 months, 23 (88.5%) patients are still alive. Three year locoregional recurrence-free survival, disease-free survival, and overall survival are 95.0%, 64.0%, and 95.0%, respectively. There have been no therapy-related deaths or secondary malignancies. The nonhematologic grade 4 toxicity rate was 7.7%. Neoadjuvant interdigitated MAI radiotherapy followed by resection and 3 cycles of adjuvant MAI has resulted in acceptable and manageable toxicity and highly favorable survival in patients at greatest risk for treatment failure.

Extreme phenophase delays and their relationship with natural forcings in Beijing over the past 260 years

Science.gov (United States)

Liu, Yang; Zhang, Mingqing; Fang, Xiuqi

2018-03-01

By merging reconstructed phenological series from published articles and observations of China Phenology Observation Network (CPON), the first blooming date of Amygdalus davidiana (FBA) in Beijing between 1741 and 2000 is reconstructed. The Butterworth method is used to remove the multi-year variations for generating the phenological series of annual variations in the first blooming date of A. davidiana. The extreme delay years in the phenological series are identified using the percentage threshold method. The characteristics of the extreme delays and the correspondence of these events with natural forcings are analysed. The main results are as follows. In annual phenological series, the extreme delays appeared in single year as main feature, only A.D.1800-1801, 1816-1817 and 1983-1984 were the events of two consecutively extreme years. Approximately 85% of the extreme delays occurred during 1-2 years after the large volcanic eruptions (VEI ≥ 4) in the eastern rim or the western rim of the Pacific Ocean, as the same proportion of the extreme delays followed El Niño events. About 73% years of the extreme delays fall in the valleys of sunspot cycles or the Dalton minimum period in the year or the previous year. According to the certainty factor (CF), the large eruptions have the greatest influence to the extreme delays; sunspot activity is the second, and ENSO is the last one. The extreme phenological delayed year is most likely to occur after a large eruption, which particularly occurs during El Niño year and its previous several years were in the descending portion or valley of sunspot phase.

Extreme value distributions

CERN Document Server

Ahsanullah, Mohammad

2016-01-01

The aim of the book is to give a through account of the basic theory of extreme value distributions. The book cover a wide range of materials available to date. The central ideas and results of extreme value distributions are presented. The book rwill be useful o applied statisticians as well statisticians interrested to work in the area of extreme value distributions.vmonograph presents the central ideas and results of extreme value distributions.The monograph gives self-contained of theory and applications of extreme value distributions.

Discovering the African freshwater "torpedo": legendary Ethiopia, religious controversies, and a catfish capable of reanimating dead fish.

Science.gov (United States)

Piccolino, Marco; Finger, Stanley; Barbara, Jean-Gaël

2011-07-01

The electric catfishes of African rivers and lakes, once depicted on Egyptian tomb art, have been largely overlooked in histories and reviews of electric fish biology and animal electricity. This article examines how Westerners, especially Dominican and Jesuit missionaries, discovered them in Ethiopia and other parts of Africa at the beginning of the seventeenth century. What transpired took place against the backdrop of tales involving the Bible, Prester John's mythical empire, and imaginary animals with fabulous powers. In effect, how they were found is related to attempts to convert Ethiopian Christians to true Catholicism, hopes of discovering great riches, and opportunities to trade, and not with the efforts of skilled natural philosophers to document and conduct experiments on the wildlife of this continent. Nevertheless, the early descriptions by Europeans circulated, and during the next century these catfishes began to be used in experiments that helped to make animal electricity a reality.

Eukaryotic evolutionary transitions are associated with extreme codon bias in functionally-related proteins.

Directory of Open Access Journals (Sweden)

Nicholas J Hudson

Full Text Available Codon bias in the genome of an organism influences its phenome by changing the speed and efficiency of mRNA translation and hence protein abundance. We hypothesized that differences in codon bias, either between-species differences in orthologous genes, or within-species differences between genes, may play an evolutionary role. To explore this hypothesis, we compared the genome-wide codon bias in six species that occupy vital positions in the Eukaryotic Tree of Life. We acquired the entire protein coding sequences for these organisms, computed the codon bias for all genes in each organism and explored the output for relationships between codon bias and protein function, both within- and between-lineages. We discovered five notable coordinated patterns, with extreme codon bias most pronounced in traits considered highly characteristic of a given lineage. Firstly, the Homo sapiens genome had stronger codon bias for DNA-binding transcription factors than the Saccharomyces cerevisiae genome, whereas the opposite was true for ribosomal proteins--perhaps underscoring transcriptional regulation in the origin of complexity. Secondly, both mammalian species examined possessed extreme codon bias in genes relating to hair--a tissue unique to mammals. Thirdly, Arabidopsis thaliana showed extreme codon bias in genes implicated in cell wall formation and chloroplast function--which are unique to plants. Fourthly, Gallus gallus possessed strong codon bias in a subset of genes encoding mitochondrial proteins--perhaps reflecting the enhanced bioenergetic efficiency in birds that co-evolved with flight. And lastly, the G. gallus genome had extreme codon bias for the Ciliary Neurotrophic Factor--which may help to explain their spontaneous recovery from deafness. We propose that extreme codon bias in groups of genes that encode functionally related proteins has a pathway-level energetic explanation.

Discovering Phonemes of Bidayuh

Directory of Open Access Journals (Sweden)

Jecky Misieng

2012-07-01

Full Text Available There are generally three views of the notion of a phoneme. The structuralist view of the phoneme focuses on this language phenomenon as a phonetic reality. In discovering phonemes of a language, phonologists who hold this view will look for minimal contrasting pairs as a way to determine contrasting sounds of that language. They will also look for allophones or two sounds of the same phoneme which may appear in complementary distribution. This paper will discuss the possible application of the structuralist approach to analyzing the phonemes of a dialect of Bidayuh, one of the Malayo-Polynesian languages spoken in the northern region of Borneo.

Astronomers Discover Fastest-Spinning Pulsar

Science.gov (United States)

2006-01-01

Astronomers using the National Science Foundation's Robert C. Byrd Green Bank Telescope have discovered the fastest-spinning neutron star ever found, a 20-mile-diameter superdense pulsar whirling faster than the blades of a kitchen blender. Their work yields important new information about the nature of one of the most exotic forms of matter known in the Universe. Pulsar Graphic Pulsars Are Spinning Neutron Stars CREDIT: Bill Saxton, NRAO/AUI/NSF (Click on image for larger version) "We believe that the matter in neutron stars is denser than an atomic nucleus, but it is unclear by how much. Our observations of such a rapidly rotating star set a hard upper limit on its size, and hence on how dense the star can be.," said Jason Hessels, a graduate student at McGill University in Montreal. Hessels and his colleagues presented their findings to the American Astronomical Society's meeting in Washington, DC. Pulsars are spinning neutron stars that sling "lighthouse beams" of radio waves or light around as they spin. A neutron star is what is left after a massive star explodes at the end of its "normal" life. With no nuclear fuel left to produce energy to offset the stellar remnant's weight, its material is compressed to extreme densities. The pressure squeezes together most of its protons and electrons to form neutrons; hence, the name "neutron star." "Neutron stars are incredible laboratories for learning about the physics of the fundamental particles of nature, and this pulsar has given us an important new limit," explained Scott Ransom, an astronomer at the National Radio Astronomy Observatory and one of Hessels' collaborators on this work. The scientists discovered the pulsar, named PSR J1748-2446ad, in a globular cluster of stars called Terzan 5, located some 28,000 light-years from Earth in the constellation Sagittarius. The newly-discovered pulsar is spinning 716 times per second, or at 716 Hertz (Hz), readily beating the previous record of 642 Hz from a pulsar

The waviness of the extratropical jet and daily weather extremes

Science.gov (United States)

Röthlisberger, Matthias; Martius, Olivia; Pfahl, Stephan

2016-04-01

In recent years the Northern Hemisphere mid-latitudes have experienced a large number of weather extremes with substantial socio-economic impact, such as the European and Russian heat waves in 2003 and 2010, severe winter floods in the United Kingdom in 2013/2014 and devastating winter storms such as Lothar (1999) and Xynthia (2010) in Central Europe. These have triggered an engaged debate within the scientific community on the role of human induced climate change in the occurrence of such extremes. A key element of this debate is the hypothesis that the waviness of the extratropical jet is linked to the occurrence of weather extremes, with a wavier jet stream favouring more extremes. Previous work on this topic is expanded in this study by analyzing the linkage between a regional measure of jet waviness and daily temperature, precipitation and wind gust extremes. We show that indeed such a linkage exists in many regions of the world, however this waviness-extremes linkage varies spatially in strength and sign. Locally, it is strong only where the relevant weather systems, in which the extremes occur, are affected by the jet waviness. Its sign depends on how the frequency of occurrence of the relevant weather systems is correlated with the occurrence of high and low jet waviness. These results go beyond previous studies by noting that also a decrease in waviness could be associated with an enhanced number of some weather extremes, especially wind gust and precipitation extremes over western Europe.

Two Newly Discovered Plants in Taiwan

OpenAIRE

Tian-Chuan Hsu; Jia-Jung Lin; Shih-Wen Chung

2009-01-01

Two herbs are newly discovered in Taiwan. Limnophila fragrans (G. Forst.) Seem. (Scrophulariaceae), native in SE Asia, is recognized from southern lowlands. Anagallis minima (L.) E. H. L. Krause (Primulaceae), native in N America and Europe, was found from northern mountainous region at low altitudes. In this study, descriptions, line drawings, color photos and a distribution map of the two species are provided.

Current concepts in repair of extremity venous injury.

Science.gov (United States)

Williams, Timothy K; Clouse, W Darrin

2016-04-01

Extremity venous injury management remains controversial. The purpose of this communication is to offer perspective as well as experiential and technical insight into extremity venous injury repair. Available literature is reviewed and discussed. Historical context is provided. Indication, the decision process for repair, including technical conduct, is delineated. In particular, the authors' experiences in both civilian and wartime injury are used for perspective. Extremity venous injury repair was championed within data from the Vietnam Vascular Registry. However, patterns of extremity venous injury differ between combat and civilian settings. Since Vietnam, civilian descriptive series opine the benefits and potential complications associated with both venous injury repair and ligation. These surround extremity edema, chronic venous insufficiency, thromboembolism, and limb loss. Whereas no clear superiority in either approach has been identified to date, there appears to be no increased risk of pulmonary embolism or chronic venous changes with repair. Newer data from the wars in Iraq and Afghanistan and meta-analysis have reinforced this and also have suggested limb salvage benefit for extremity venous repair in combined arterial and venous injuries in modern settings. The patient's physiologic state and associated injury drive five triage categories suggesting vein injury management. Vein repair thrombosis occurs in a significant proportion, yet many recanalize and possibly have a positive impact on limb venous return. Further, early decompression favors reduced blood loss, acute edema, and inflammation, supporting collateral development. Large soft tissue injury minimizing collateral capacity increases the importance of repair. Constructs of repair are varied with modest differences in patency. Venous shunting is feasible, but specific roles remain nebulous. An aggressive posture toward extremity venous injury repair seems justified today because of the likely

Discovering Land Cover Web Map Services from the Deep Web with JavaScript Invocation Rules

Directory of Open Access Journals (Sweden)

Dongyang Hou

2016-06-01

-based approach. This result shows that the proposed crawler has the ability to discover WMSs hidden in JavaScript code. The second experiment uses 4842 seed URLs updated daily. The crawler found a total of 17,874 available WMSs, of which 11,901 were LCWMSs. Our approach discovered a greater number of services than those found using previous approaches. It indicates that the proposed crawler has a large advantage in discovering LCWMSs from the surface web and from JavaScript code. Furthermore, a simple case study demonstrates that the designed LCWMS search engine represents an important step towards realizing land cover information integration for global mapping and monitoring purposes.

Extreme Nonlinear Optics An Introduction

CERN Document Server

Wegener, Martin

2005-01-01

Following the birth of the laser in 1960, the field of "nonlinear optics" rapidly emerged. Today, laser intensities and pulse durations are readily available, for which the concepts and approximations of traditional nonlinear optics no longer apply. In this regime of "extreme nonlinear optics," a large variety of novel and unusual effects arise, for example frequency doubling in inversion symmetric materials or high-harmonic generation in gases, which can lead to attosecond electromagnetic pulses or pulse trains. Other examples of "extreme nonlinear optics" cover diverse areas such as solid-state physics, atomic physics, relativistic free electrons in a vacuum and even the vacuum itself. This book starts with an introduction to the field based primarily on extensions of two famous textbook examples, namely the Lorentz oscillator model and the Drude model. Here the level of sophistication should be accessible to any undergraduate physics student. Many graphical illustrations and examples are given. The followi...

Challenges in service mining : record, check, discover

NARCIS (Netherlands)

Aalst, van der W.M.P.; Daniel, F.; Dolog, P.; Li, Q.

2013-01-01

Process mining aims to discover, monitor and improve real processes by extracting knowledge from event logs abundantly available in today’s information systems. Although process mining has been applied in hundreds of organizations and process mining techniques have been embedded in a variety of

AN EXTREME ANALOGUE OF ϵ AURIGAE: AN M-GIANT ECLIPSED EVERY 69 YEARS BY A LARGE OPAQUE DISK SURROUNDING A SMALL HOT SOURCE

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, Joseph E.; Stassun, Keivan G.; Lund, Michael B.; Conroy, Kyle E. [Department of Physics and Astronomy, Vanderbilt University, 6301 Stevenson Center, Nashville, TN 37235 (United States); Siverd, Robert J. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Santa Barbara, CA 93117 (United States); Pepper, Joshua [Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, PA 18015 (United States); Tang, Sumin [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kafka, Stella [American Association of Variable Star Observers, 49 Bay State Road, Cambridge, MA 02138 (United States); Gaudi, B. Scott; Stevens, Daniel J.; Kochanek, Christopher S. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Beatty, Thomas G. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Shappee, Benjamin J. [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

2016-05-01

We present TYC 2505-672-1 as a newly discovered and remarkable eclipsing system comprising an M-type red giant that undergoes a ∼3.45 year long, near-total eclipse (depth of ∼4.5 mag) with a very long period of ∼69.1 years. TYC 2505-672-1 is now the longest-period eclipsing binary system yet discovered, more than twice as long as that of the currently longest-period system, ϵ Aurigae. We show from analysis of the light curve including both our own data and historical data spanning more than 120 years and from modeling of the spectral energy distribution, both before and during eclipse, that the red giant primary is orbited by a moderately hot source ( T {sub eff} ≈ 8000 K) that is itself surrounded by an extended, opaque circumstellar disk. From the measured ratio of luminosities, the radius of the hot companion must be in the range of 0.1–0.5 R {sub ⊙} (depending on the assumed radius of the red giant primary), which is an order of magnitude smaller than that for a main sequence A star and 1–2 orders of magnitude larger than that for a white dwarf. The companion is therefore most likely a “stripped red giant” subdwarf-B type star destined to become a He white dwarf. It is, however, somewhat cooler than most sdB stars, implying a very low mass for this “pre-He-WD” star. The opaque disk surrounding this hot source may be a remnant of the stripping of its former hydrogen envelope. However, it is puzzling how this object became stripped, given that it is at present so distant (orbital semimajor axis of ∼24 au) from the current red giant primary star. Extrapolating from our calculated ephemeris, the next eclipse should begin in early UT 2080 April and end in mid UT 2083 September (eclipse center UT 2081 December 24). In the meantime, radial velocity observations would establish the masses of the components, and high-cadence UV observations could potentially reveal oscillations of the hot companion that would further constrain its evolutionary

Extreme morphologies of mantis shrimp larvae

OpenAIRE

Haug, Carolin; Ahyong, Shane T.; Wiethase, Joris H.; Olesen, Jørgen; Haug, Joachim T.

2016-01-01

ABSTRACT Larvae of stomatopods (mantis shrimps) are generally categorized into four larval types: antizoea, pseudozoea (both representing early larval stages), alima and erichthus (the latter two representing later larval stages). These categories, however, do not reflect the existing morphological diversity of stomatopod larvae, which is largely unstudied. We describe here four previously unknown larval types with extreme morphologies. All specimens were found in the collections of the Zoolo...

The Magic of Mathematics Discovering the Spell of Mathematics

CERN Document Server

Pappas, Theoni

2011-01-01

Delves into the world of ideas, explores the spell mathematics casts on our lives, and helps you discover mathematics where you least expect it. Be spellbound by the mathematical designs found in nature. Learn how knots may untie the mysteries of life. Be mesmerized by the computer revolution. Discover how the hidden forces of mathematics hold architectural structures together connect your telephone calls help airplanes get off the ground solve the mysteries of the living cell. See how some artists use a mathematical palette in their works and how many writers draw upon the wealth of its ideas

Large-Scale Constraint-Based Pattern Mining

Science.gov (United States)

Zhu, Feida

2009-01-01

We studied the problem of constraint-based pattern mining for three different data formats, item-set, sequence and graph, and focused on mining patterns of large sizes. Colossal patterns in each data formats are studied to discover pruning properties that are useful for direct mining of these patterns. For item-set data, we observed robustness of…

MAD about the Large Magellanic Cloud Preparing for the era of Extremely Large Telescopes

NARCIS (Netherlands)

Fiorentino, G.; Tolstoy, E.; Diolaiti, E.; Valenti, E.; Cignoni, M.; Mackey, A. D.

We present J, H, K-s photometry from the the Multi conjugate Adaptive optics Demonstrator (MAD), a visitor instrument at the VLT, of a resolved stellar population in a small crowded field in the bar of the Large Magellanic Cloud near the globular cluster NGC 1928. In a total exposure time of 6, 36

Towards constraining extreme temperature projections of the CMIP5 ensemble

Science.gov (United States)

Vogel, Martha-Marie; Orth, René; Isabelle Seneviratne, Sonia

2016-04-01

The frequency and intensity of heat waves is expected to change in future in response to global warming. Given the severe impacts of heat waves on ecosystems and society it is important to understand how and where they will intensify. Projections of extreme hot temperatures in the IPCC AR5 model ensemble show large uncertainties for projected changes of extreme temperatures in particular in Central Europe. In this region land-atmosphere coupling can contribute substantially to the development of heat waves. This coupling is also subject to change in future, while model projections display considerable spread. In this work we link projections of changes in extreme temperatures and of changes in land-atmosphere interactions with a particular focus on Central Europe. Uncertainties in projected extreme temperatures can be partly explained by different projected changes of the interplay between latent heat and temperature as well as soil moisture. Given the considerable uncertainty in land-atmosphere coupling representation already in the current climate, we furthermore employ observational data sets to constrain the model ensemble, and consequently the extreme temperature projections.

Large field radiotherapy

International Nuclear Information System (INIS)

Vanasek, J.; Chvojka, Z.; Zouhar, M.

1984-01-01

Calculations may prove that irradiation procedures, commonly used in radiotherapy and represented by large-capacity irradiation techniques, do not exceed certain limits of integral doses with favourable radiobiological action on the organism. On the other hand integral doses in supralethal whole-body irradiation, used in the therapy of acute leukemia, represent radiobiological values which without extreme and exceptional further interventions and teamwork are not compatible with life, and the radiotherapeutist cannot use such high doses without the backing of a large team. (author)

Extremely Preterm Birth

Science.gov (United States)

... Events Advocacy For Patients About ACOG Extremely Preterm Birth Home For Patients Search FAQs Extremely Preterm Birth ... Spanish FAQ173, June 2016 PDF Format Extremely Preterm Birth Pregnancy When is a baby considered “preterm” or “ ...

Life at extreme conditions: neutron scattering studies of biological molecules suggest that evolution selected dynamics

International Nuclear Information System (INIS)

Zaccai, Joseph Giuseppe

2008-01-01

The short review concentrates on recent work performed at the neutrons in biology laboratories of the Institut Laue Langevin and Institut de Biologie Structurale in Grenoble. Extremophile organisms have been discovered that require extreme conditions of temperature, pressure or solvent environment for survival. The existence of such organisms poses a significant challenge in understanding the physical chemistry of their proteins, in view of the great sensitivity of protein structure and stability to the aqueous environment and to external conditions in general. Results of neutron scattering measurements on the dynamics of proteins from extremophile organisms, in vitro as well as in vivo, indicated remarkably how adaptation to extreme conditions involves forces and fluctuation amplitudes that have been selected specifically, suggesting that evolutionary macromolecular selection proceeded via dynamics. The experiments were performed on a halophilic protein, and membrane adapted to high salt, a thermophilic enzyme adapted to high temperature and its mesophilic (adapted to 37 degC) homologue; and in vivo for psychrophilic, mesophilic, thermophilic and hyperthermophilic bacteria, adapted respectively to temperatures of 4 degC, 37 degC, 75 degC and 85 degC. Further work demonstrated the existence of a water component of exceptionally low mobility in an extreme halophile from the Dead Sea, which is not present in mesophile bacterial cells. (author)

The Biological Effect of Extremely Low Frequency Electromagnetic Fields and Vibrations on Barley Seed Hydration and Germination

Directory of Open Access Journals (Sweden)

Armine Amyan

2004-01-01

Full Text Available The changes of wet and dry weights and germination of barley seed in different periods of its swelling in nontreated (control, extremely low frequency electromagnetic fields (ELF EMF –treated, and extremely low frequency vibrations (ELFV–treated cold (4°C and warm (20°C distilled water (DW were studied. The metabolic-dependent seed hydration, dry weight dissolving, germination, and water binding in seed were modulated by preliminary EMF- and ELFV-treated DW. Frequency “windows” for the effect of EMF and ELFV on seed hydration, solubility, water binding in seed, and germination were discovered. These “windows” were different for EMF and ELFV, as well as in various phases of seed swelling. It is suggested that EMF-induced water structure modification has a different biological effect on the process of seed hydration, solubility, water binding in seed, and germination compared to ELFV.

Two Newly Discovered Plants in Taiwan

Directory of Open Access Journals (Sweden)

Tian-Chuan Hsu

2009-11-01

Full Text Available Two herbs are newly discovered in Taiwan. Limnophila fragrans (G. Forst. Seem. (Scrophulariaceae, native in SE Asia, is recognized from southern lowlands. Anagallis minima (L. E. H. L. Krause (Primulaceae, native in N America and Europe, was found from northern mountainous region at low altitudes. In this study, descriptions, line drawings, color photos and a distribution map of the two species are provided.

Prospect for extreme field science

Energy Technology Data Exchange (ETDEWEB)

Tajima, T. [Ludwig Maximilian Univ. and Max Planck Institute for Quantum Optics, Garching (Germany); Japan Atomic Energy Agency, Kyoto and KEK, Tsukuba (Japan)

2009-11-15

The kind of laser extreme light infrastructure (ELI) provides will usher in a class of experiments we have only dreamed of for years. The characteristics that ELI brings in include: the highest intensity ever, large fluence, and relatively high repetition rate. A personal view of the author on the prospect of harnessing this unprecedented opportunity for advancing science of extreme fields is presented. The first characteristic of ELI, its intensity, will allow us to access, as many have stressed already, extreme fields that hover around the Schwinger field or at the very least the neighboring fields in which vacuum begins to behave as a nonlinear medium. In this sense, we are seriously probing the 'material' property of vacuum and thus the property that theory of relativity itself described and will entail. We will probe both special theory and general theory of relativity in regimes that have been never tested so far. We may see a glimpse into the reach of relativity or even its breakdown in some extreme regimes. We will learn Einstein and may even go beyond Einstein, if our journey is led. Laser-driven acceleration both by the laser field itself and by the wakefield that is triggered in a plasma is huge. Energies, if not luminosity, we can access, may be unprecedented going far beyond TeV. The nice thing about ELI is that it has relatively high repetition rate and average fluence as compared with other extreme lasers. This high fluence can be a key element that leads to applications to high energy physics, such as gamma-gamma collider driver experiment, and some gamma ray experiments that may be relevant in the frontier of photo-nuclear physics, and atomic energy applications. Needless to say, high fluence is one of most important features that industrial and medical applications may need. If we are lucky, we may see a door opens at the frontier of novel physics that may not be available by any other means. (authors)

PENERAPAN GLOBAL EXTREME PROGRAMMING PADA SISTEM INFORMASI WORKSHOP, SEMINAR DAN PELATIHAN DI LEMBAGA EDUKASI

Directory of Open Access Journals (Sweden)

Baginda Oloan Lubis

2016-09-01

Full Text Available Abstract Institutions of education as one of the service agencies workshops, seminars and training with information systems that are still manual at the time of printing id cards, the manufacture of attendance, printing certificates and report generation often had difficulty in searching data and other impacts arising from manual systems. Therefore the design of information systems or desktop based application creation is a solution to provide convenience to the user in the process of data processing, data retrieval to preparing reports. Model systems development workshops, seminars and training used in the design of information systems workshops, seminars and training using a model of Agile Software Development, which was discovered and developed by Robert Cecil Martin with process models Global Extreme Programming, namely the development of XP (Extreme Programming Life Cycle. While the tools used by the UML (Unifed Modeling Language and ERD (Entity Relationship Diagram. Hopefully, by the design of this system will allow a user who uses the id card printing, manufacture of attendance, certificate printing and reporting each end of the activity.

Historical and projected trends in temperature and precipitation extremes in Australia in observations and CMIP5

OpenAIRE

Alexander, Lisa V.; Arblaster, Julie M.

2017-01-01

This study expands previous work on climate extremes in Australia by investigating the simulation of a large number of extremes indices in the CMIP5 multi-model dataset and comparing them to multiple observational datasets over a century of observed data using consistent methods. We calculate 24 indices representing extremes of temperature and precipitation from 1911 to 2010 over Australia and show that there have been significant observed trends in temperature extremes associated with warmin...

Large-strain time-temperature equivalence in high density polyethylene for prediction of extreme deformation and damage

Directory of Open Access Journals (Sweden)

Gray G.T.

2012-08-01

Full Text Available Time-temperature equivalence is a widely recognized property of many time-dependent material systems, where there is a clear predictive link relating the deformation response at a nominal temperature and a high strain-rate to an equivalent response at a depressed temperature and nominal strain-rate. It has been found that high-density polyethylene (HDPE obeys a linear empirical formulation relating test temperature and strain-rate. This observation was extended to continuous stress-strain curves, such that material response measured in a load frame at large strains and low strain-rates (at depressed temperatures could be translated into a temperature-dependent response at high strain-rates and validated against Taylor impact results. Time-temperature equivalence was used in conjuction with jump-rate compression tests to investigate isothermal response at high strain-rate while exluding adiabatic heating. The validated constitutive response was then applied to the analysis of Dynamic-Tensile-Extrusion of HDPE, a tensile analog to Taylor impact developed at LANL. The Dyn-Ten-Ext test results and FEA found that HDPE deformed smoothly after exiting the die, and after substantial drawing appeared to undergo a pressure-dependent shear damage mechanism at intermediate velocities, while it fragmented at high velocities. Dynamic-Tensile-Extrusion, properly coupled with a validated constitutive model, can successfully probe extreme tensile deformation and damage of polymers.

Prevention through policy: Urban macroplastic leakages to the marine environment during extreme rainfall events

OpenAIRE

Axelsson, Charles; van Sebille, Erik

2017-01-01

The leakage of large plastic litter (macroplastics) into the ocean is a major environmental problem. A significant fraction of this leakage originates from coastal cities, particularly during extreme rainfall events. As coastal cities continue to grow, finding ways to reduce this macroplastic leakage is extremely pertinent. Here, we explore why and how coastal cities can reduce macroplastic leakages during extreme rainfall events. Using nine global cities as a basis, we establish that while c...

Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts

Science.gov (United States)

Frank, Dorothea; Reichstein, Markus; Bahn, Michael; Thonicke, Kirsten; Frank, David; Mahecha, Miguel D; Smith, Pete; van der Velde, Marijn; Vicca, Sara; Babst, Flurin; Beer, Christian; Buchmann, Nina; Canadell, Josep G; Ciais, Philippe; Cramer, Wolfgang; Ibrom, Andreas; Miglietta, Franco; Poulter, Ben; Rammig, Anja; Seneviratne, Sonia I; Walz, Ariane; Wattenbach, Martin; Zavala, Miguel A; Zscheischler, Jakob

2015-01-01

Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global

A Systematic Mid-Infrared Survey of A Sample of Tidal Disruption Events Discovered by ZTF

Science.gov (United States)

Yan, Lin; Van, Sjoert; Kulkarni, Shri; Kasliwal, Mansi; Gezari, Suvi; Cenko, Brad; Blagorodnova, Nadia; Hung, Tiara

2017-12-01

Zwicky Transient Facility (ZTF) saw its first light (press release on Nov 14, 2017) and is currently in the commissioning phase. The science operation is scheduled to start on Feb 1, 2018. Based on the data from Palomar Transient Factory (PTF), ZTF is expected to discover 30 new tidal disruption events (TDE) in the centers of galaxies containing supermassive blackholes. TDEs are rare transient events, and have only been discovered in recent years by large area transient surveys. Observations of optically discovered TDEs appear to show common characteristics, including blackbody temperatures of a few 10,000K, derived bolometric peak luminosities of several 10^43 - 10^44 erg/s, and photospheric radius of 10^15 - 10^16 cm. These properties are in conflict with the classic TDE model predictions, which suggest an order of magnitude higher temperature and peak luminosity. One proposed explanation is the possible existence of a reprocessing gas layer which absorbs X-ray, UV/optical photons and produces a cooler spectral energy distribution (SED). So far, there are only two published mid-IR light curves of TDEs, each with two epochal data. To solve this mystery, we require higher cadence Spitzer observations of a sample of uniformly selected TDEs. Next year is the only opportunity to obtain the critical observations because Spitzer is expected to operate only to March 2019. We request 24.1 hours of Spitzer time to observe 7 ZTF TDEs. This will produce a unique legacy dataset for many future studies of physics of TDEs.

Extreme environment electronics

CERN Document Server

Cressler, John D

2012-01-01

Unfriendly to conventional electronic devices, circuits, and systems, extreme environments represent a serious challenge to designers and mission architects. The first truly comprehensive guide to this specialized field, Extreme Environment Electronics explains the essential aspects of designing and using devices, circuits, and electronic systems intended to operate in extreme environments, including across wide temperature ranges and in radiation-intense scenarios such as space. The Definitive Guide to Extreme Environment Electronics Featuring contributions by some of the world's foremost exp

Life in the salinity gradient: Discovering mechanisms behind a new biodiversity pattern

Science.gov (United States)

Telesh, Irena; Schubert, Hendrik; Skarlato, Sergei

2013-12-01

A recently discovered paradoxical maximum of planktonic protistan species in the salinity gradient of the Baltic Sea revealed an inverse trend of species number/salinity relation in comparison to the previously accepted species-minimum model for macrozoobenthos. Here, we review long-term data on organisms of different size classes and ecological groups to show that eukaryotic and prokaryotic microbes in plankton demonstrate a maximum species richness in the challenging zone of the critical salinity 5-8, where the large-bodied bottom dwellers (macrozoobenthos, macroalgae and aquatic higher plants) experience large-scale salinity stress which leads to an impoverished diversity. We propose a new conceptual model to explain why the diversity of small, fast-developing, rapidly evolving unicellular plankton organisms benefits from relative vacancy of brackish-water ecological niches and impaired competitiveness therein. The ecotone theory, Hutchinson's Ecological Niche Concept, species-area relationships and the Intermediate Disturbance Hypothesis are considered as a theoretical framework for understanding extinctions, speciation and variations in the evolution rates of different aquatic species in ecosystems with the pronounced salinity gradient.

Large mass hierarchies from strongly-coupled dynamics

Energy Technology Data Exchange (ETDEWEB)

Athenodorou, Andreas [Department of Physics, University of Cyprus,B.O. Box 20537, 1678 Nicosia (Cyprus); Bennett, Ed [Department of Physics, College of Science, Swansea University,Singleton Park, Swansea SA2 8PP (United Kingdom); Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI),Nagoya University,Furo, Chikusa, Nagoya 464-8602 (Japan); Bergner, Georg [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics,University of Bern,Sidlerstrasse 5, CH-3012 Bern (Switzerland); Elander, Daniel [National Institute for Theoretical Physics, School of Physics andMandelstam Institute for Theoretical Physics, University of the Witwatersrand,1 Jan Smuts Avenue, Johannesburg, Wits 2050 (South Africa); Lin, C.-J. David [Institute of Physics, National Chiao-Tung University,1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan (China); CNRS, Aix Marseille Université, Université de Toulon, Centre de Physique Théorique,UMR 7332, F-13288 Marseille (France); Lucini, Biagio; Piai, Maurizio [Department of Physics, College of Science, Swansea University,Singleton Park, Swansea SA2 8PP (United Kingdom)

2016-06-20

Besides the Higgs particle discovered in 2012, with mass 125 GeV, recent LHC data show tentative signals for new resonances in diboson as well as diphoton searches at high center-of-mass energies (2 TeV and 750 GeV, respectively). If these signals are confirmed (or other new resonances are discovered at the TeV scale), the large hierarchies between masses of new bosons require a dynamical explanation. Motivated by these tentative signals of new physics, we investigate the theoretical possibility that large hierarchies in the masses of glueballs could arise dynamically in new strongly-coupled gauge theories extending the standard model of particle physics. We study lattice data on non-Abelian gauge theories in the (near-)conformal regime as well as a simple toy model in the context of gauge/gravity dualities. We focus our attention on the ratio R between the mass of the lightest spin-2 and spin-0 resonances, that for technical reasons is a particularly convenient and clean observable to study. For models in which (non-perturbative) large anomalous dimensions arise dynamically, we show indications that this mass ratio can be large, with R>5. Moreover, our results suggest that R might be related to universal properties of the IR fixed point. Our findings provide an interesting step towards understanding large mass ratios in the non-perturbative regime of quantum field theories with (near) IR conformal behaviour.

Discovering approximate-associated sequence patterns for protein-DNA interactions

KAUST Repository

Chan, Tak Ming

2010-12-30

Motivation: The bindings between transcription factors (TFs) and transcription factor binding sites (TFBSs) are fundamental protein-DNA interactions in transcriptional regulation. Extensive efforts have been made to better understand the protein-DNA interactions. Recent mining on exact TF-TFBS-associated sequence patterns (rules) has shown great potentials and achieved very promising results. However, exact rules cannot handle variations in real data, resulting in limited informative rules. In this article, we generalize the exact rules to approximate ones for both TFs and TFBSs, which are essential for biological variations. Results: A progressive approach is proposed to address the approximation to alleviate the computational requirements. Firstly, similar TFBSs are grouped from the available TF-TFBS data (TRANSFAC database). Secondly, approximate and highly conserved binding cores are discovered from TF sequences corresponding to each TFBS group. A customized algorithm is developed for the specific objective. We discover the approximate TF-TFBS rules by associating the grouped TFBS consensuses and TF cores. The rules discovered are evaluated by matching (verifying with) the actual protein-DNA binding pairs from Protein Data Bank (PDB) 3D structures. The approximate results exhibit many more verified rules and up to 300% better verification ratios than the exact ones. The customized algorithm achieves over 73% better verification ratios than traditional methods. Approximate rules (64-79%) are shown statistically significant. Detailed variation analysis and conservation verification on NCBI records demonstrate that the approximate rules reveal both the flexible and specific protein-DNA interactions accurately. The approximate TF-TFBS rules discovered show great generalized capability of exploring more informative binding rules. © The Author 2010. Published by Oxford University Press. All rights reserved.

Investigation of the relationship between hurricane waves and extreme runup

Science.gov (United States)

Thompson, D. M.; Stockdon, H. F.

2006-12-01

In addition to storm surge, the elevation of wave-induced runup plays a significant role in forcing geomorphic change during extreme storms. Empirical formulations for extreme runup, defined as the 2% exceedence level, are dependent on some measure of significant offshore wave height. Accurate prediction of extreme runup, particularly during hurricanes when wave heights are large, depends on selecting the most appropriate measure of wave height that provides energy to the nearshore system. Using measurements from deep-water wave buoys results in an overprediction of runup elevation. Under storm forcing these large waves dissipate across the shelf through friction, whitecapping and depth-limited breaking before reaching the beach and forcing swash processes. The use of a local, shallow water wave height has been shown to provide a more accurate estimate of extreme runup elevation (Stockdon, et. al. 2006); however, a specific definition of this local wave height has yet to be defined. Using observations of nearshore waves from the U.S. Army Corps of Engineers' Field Research Facility (FRF) in Duck, NC during Hurricane Isabel, the most relevant measure of wave height for use in empirical runup parameterizations was examined. Spatial and temporal variability of the hurricane wave field, which made landfall on September 18, 2003, were modeled using SWAN. Comparisons with wave data from FRF gages and deep-water buoys operated by NOAA's National Data Buoy Center were used for model calibration. Various measures of local wave height (breaking, dissipation-based, etc.) were extracted from the model domain and used as input to the runup parameterizations. Video based observations of runup collected at the FRF during the storm were used to ground truth modeled values. Assessment of the most appropriate measure of wave height can be extended over a large area through comparisons to observations of storm- induced geomorphic change.

Sea Extremes: Integrated impact assessment in coastal climate adaptation

DEFF Research Database (Denmark)

Sørensen, Carlo Sass; Knudsen, Per; Broge, Niels

2016-01-01

protection measures, topography, and infrastructure to provide a more complete picture of the water-related impact from climate change at an exposed coastal location. Results show that future sea extremes evaluated from extreme value statistics may, indeed, have a large impact. The integrated effects from......We investigate effects of sea level rise and a change in precipitation pattern on coastal flooding hazards. Historic and present in situ and satellite data of water and groundwater levels, precipitation, vertical ground motion, geology,and geotechnical soil properties are combined with flood...... research advances and projections for the future are updated....

Exome sequencing in schizophrenic patients with high levels of homozygosity identifies novel and extremely rare mutations in the GABA/glutamatergic pathways.

Directory of Open Access Journals (Sweden)

Edoardo Giacopuzzi

Full Text Available Inbreeding is a known risk factor for recessive Mendelian diseases and previous studies have suggested that it could also play a role in complex disorders, such as psychiatric diseases. Recent inbreeding results in the presence of long runs of homozygosity (ROHs along the genome, which are also defined as autozygosity regions. Genetic variants in these regions have two alleles that are identical by descent, thus increasing the odds of bearing rare recessive deleterious mutations due to a homozygous state. A recent study showed a suggestive enrichment of long ROHs in schizophrenic patients, suggesting that recent inbreeding could play a role in the disease. To better understand the impact of autozygosity on schizophrenia risk, we selected, from a cohort of 180 Italian patients, seven subjects with extremely high numbers of large ROHs that were likely due to recent inbreeding and characterized the mutational landscape within their ROHs using Whole Exome Sequencing and, gene set enrichment analysis. We identified a significant overlap (17%; empirical p-value = 0.0171 between genes inside ROHs affected by low frequency functional homozygous variants (107 genes and the group of most promising candidate genes mutated in schizophrenia. Moreover, in four patients, we identified novel and extremely rare damaging mutations in the genes involved in neurodevelopment (MEGF8 and in GABA/glutamatergic synaptic transmission (GAD1, FMN1, ANO2. These results provide insights into the contribution of rare recessive mutations and inbreeding as risk factors for schizophrenia. ROHs that are likely due to recent inbreeding harbor a combination of predisposing low-frequency variants and extremely rare variants that have a high impact on pivotal biological pathways implicated in the disease. In addition, this study confirms that focusing on patients with high levels of homozygosity could be a useful prioritization strategy for discovering new high-impact mutations in

Exome sequencing in schizophrenic patients with high levels of homozygosity identifies novel and extremely rare mutations in the GABA/glutamatergic pathways.

Science.gov (United States)

Giacopuzzi, Edoardo; Gennarelli, Massimo; Minelli, Alessandra; Gardella, Rita; Valsecchi, Paolo; Traversa, Michele; Bonvicini, Cristian; Vita, Antonio; Sacchetti, Emilio; Magri, Chiara

2017-01-01

Inbreeding is a known risk factor for recessive Mendelian diseases and previous studies have suggested that it could also play a role in complex disorders, such as psychiatric diseases. Recent inbreeding results in the presence of long runs of homozygosity (ROHs) along the genome, which are also defined as autozygosity regions. Genetic variants in these regions have two alleles that are identical by descent, thus increasing the odds of bearing rare recessive deleterious mutations due to a homozygous state. A recent study showed a suggestive enrichment of long ROHs in schizophrenic patients, suggesting that recent inbreeding could play a role in the disease. To better understand the impact of autozygosity on schizophrenia risk, we selected, from a cohort of 180 Italian patients, seven subjects with extremely high numbers of large ROHs that were likely due to recent inbreeding and characterized the mutational landscape within their ROHs using Whole Exome Sequencing and, gene set enrichment analysis. We identified a significant overlap (17%; empirical p-value = 0.0171) between genes inside ROHs affected by low frequency functional homozygous variants (107 genes) and the group of most promising candidate genes mutated in schizophrenia. Moreover, in four patients, we identified novel and extremely rare damaging mutations in the genes involved in neurodevelopment (MEGF8) and in GABA/glutamatergic synaptic transmission (GAD1, FMN1, ANO2). These results provide insights into the contribution of rare recessive mutations and inbreeding as risk factors for schizophrenia. ROHs that are likely due to recent inbreeding harbor a combination of predisposing low-frequency variants and extremely rare variants that have a high impact on pivotal biological pathways implicated in the disease. In addition, this study confirms that focusing on patients with high levels of homozygosity could be a useful prioritization strategy for discovering new high-impact mutations in genetically

MICRO-STRUCTURAL INVESTIGATION OF SOME ARTIFACTS DISCOVERED AT POROLISSUM

Directory of Open Access Journals (Sweden)

MUNTEANU Mihai

2014-09-01

Full Text Available the paper presents the investigation of two fragments of roman bronze artefacts, discovered during archaeological works performed at Porolissum, an important military and economical point on the northern limes of Dacia Province. One of the analyzed fragments (Mi1 was taken from a consistent fragment of a Roman bronze statue, while the second (Mi2 was among a lot of small metal pieces, discovered in the same investigated area. Using highly sophisticated micro-structural analysing techniques – X-Ray diffraction, the paper investigates the possibility that the Mi2 fragment may have belonged to the same statue from which the sample Mi1 was taken

Drivers and seasonal predictability of extreme wind speeds in the ECMWF System 4 and a statistical model

Science.gov (United States)

Walz, M. A.; Donat, M.; Leckebusch, G. C.

2017-12-01

As extreme wind speeds are responsible for large socio-economic losses in Europe, a skillful prediction would be of great benefit for disaster prevention as well as for the actuarial community. Here we evaluate patterns of large-scale atmospheric variability and the seasonal predictability of extreme wind speeds (e.g. >95th percentile) in the European domain in the dynamical seasonal forecast system ECMWF System 4, and compare to the predictability based on a statistical prediction model. The dominant patterns of atmospheric variability show distinct differences between reanalysis and ECMWF System 4, with most patterns in System 4 extended downstream in comparison to ERA-Interim. The dissimilar manifestations of the patterns within the two models lead to substantially different drivers associated with the occurrence of extreme winds in the respective model. While the ECMWF System 4 is shown to provide some predictive power over Scandinavia and the eastern Atlantic, only very few grid cells in the European domain have significant correlations for extreme wind speeds in System 4 compared to ERA-Interim. In contrast, a statistical model predicts extreme wind speeds during boreal winter in better agreement with the observations. Our results suggest that System 4 does not seem to capture the potential predictability of extreme winds that exists in the real world, and therefore fails to provide reliable seasonal predictions for lead months 2-4. This is likely related to the unrealistic representation of large-scale patterns of atmospheric variability. Hence our study points to potential improvements of dynamical prediction skill by improving the simulation of large-scale atmospheric dynamics.

Causes of Glacier Melt Extremes in the Alps Since 1949

Science.gov (United States)

Thibert, E.; Dkengne Sielenou, P.; Vionnet, V.; Eckert, N.; Vincent, C.

2018-01-01

Recent record-breaking glacier melt values are attributable to peculiar extreme events and long-term warming trends that shift averages upward. Analyzing one of the world's longest mass balance series with extreme value statistics, we show that detrending melt anomalies makes it possible to disentangle these effects, leading to a fairer evaluation of the return period of melt extreme values such as 2003, and to characterize them by a more realistic bounded behavior. Using surface energy balance simulations, we show that three independent drivers control melt: global radiation, latent heat, and the amount of snow at the beginning of the melting season. Extremes are governed by large deviations in global radiation combined with sensible heat. Long-term trends are driven by the lengthening of melt duration due to earlier and longer-lasting melting of ice along with melt intensification caused by trends in long-wave irradiance and latent heat due to higher air moisture.

Decision Tree Approach to Discovering Fraud in Leasing Agreements

Directory of Open Access Journals (Sweden)

Horvat Ivan

2014-09-01

Full Text Available Background: Fraud attempts create large losses for financing subjects in modern economies. At the same time, leasing agreements have become more and more popular as a means of financing objects such as machinery and vehicles, but are more vulnerable to fraud attempts. Objectives: The goal of the paper is to estimate the usability of the data mining approach in discovering fraud in leasing agreements. Methods/Approach: Real-world data from one Croatian leasing firm was used for creating tow models for fraud detection in leasing. The decision tree method was used for creating a classification model, and the CHAID algorithm was deployed. Results: The decision tree model has indicated that the object of the leasing agreement had the strongest impact on the probability of fraud. Conclusions: In order to enhance the probability of the developed model, it would be necessary to develop software that would enable automated, quick and transparent retrieval of data from the system, processing according to the rules and displaying the results in multiple categories.

Extreme-Scale De Novo Genome Assembly

Energy Technology Data Exchange (ETDEWEB)

Georganas, Evangelos [Intel Corporation, Santa Clara, CA (United States); Hofmeyr, Steven [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Genome Inst.; Egan, Rob [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Computational Research Division; Buluc, Aydin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Genome Inst.; Oliker, Leonid [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Genome Inst.; Rokhsar, Daniel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Computational Research Division; Yelick, Katherine [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Genome Inst.

2017-09-26

De novo whole genome assembly reconstructs genomic sequence from short, overlapping, and potentially erroneous DNA segments and is one of the most important computations in modern genomics. This work presents HipMER, a high-quality end-to-end de novo assembler designed for extreme scale analysis, via efficient parallelization of the Meraculous code. Genome assembly software has many components, each of which stresses different components of a computer system. This chapter explains the computational challenges involved in each step of the HipMer pipeline, the key distributed data structures, and communication costs in detail. We present performance results of assembling the human genome and the large hexaploid wheat genome on large supercomputers up to tens of thousands of cores.

Long-term statistics of extreme tsunami height at Crescent City

Science.gov (United States)

Dong, Sheng; Zhai, Jinjin; Tao, Shanshan

2017-06-01

Historically, Crescent City is one of the most vulnerable communities impacted by tsunamis along the west coast of the United States, largely attributed to its offshore geography. Trans-ocean tsunamis usually produce large wave runup at Crescent Harbor resulting in catastrophic damages, property loss and human death. How to determine the return values of tsunami height using relatively short-term observation data is of great significance to assess the tsunami hazards and improve engineering design along the coast of Crescent City. In the present study, the extreme tsunami heights observed along the coast of Crescent City from 1938 to 2015 are fitted using six different probabilistic distributions, namely, the Gumbel distribution, the Weibull distribution, the maximum entropy distribution, the lognormal distribution, the generalized extreme value distribution and the generalized Pareto distribution. The maximum likelihood method is applied to estimate the parameters of all above distributions. Both Kolmogorov-Smirnov test and root mean square error method are utilized for goodness-of-fit test and the better fitting distribution is selected. Assuming that the occurrence frequency of tsunami in each year follows the Poisson distribution, the Poisson compound extreme value distribution can be used to fit the annual maximum tsunami amplitude, and then the point and interval estimations of return tsunami heights are calculated for structural design. The results show that the Poisson compound extreme value distribution fits tsunami heights very well and is suitable to determine the return tsunami heights for coastal disaster prevention.

A strategy to discover new organizers identifies a putative heart organizer.

Science.gov (United States)

Anderson, Claire; Khan, Mohsin A F; Wong, Frances; Solovieva, Tatiana; Oliveira, Nidia M M; Baldock, Richard A; Tickle, Cheryll; Burt, Dave W; Stern, Claudio D

2016-08-25

Organizers are regions of the embryo that can both induce new fates and impart pattern on other regions. So far, surprisingly few organizers have been discovered, considering the number of patterned tissue types generated during development. This may be because their discovery has relied on transplantation and ablation experiments. Here we describe a new approach, using chick embryos, to discover organizers based on a common gene expression signature, and use it to uncover the anterior intestinal portal (AIP) endoderm as a putative heart organizer. We show that the AIP can induce cardiac identity from non-cardiac mesoderm and that it can pattern this by specifying ventricular and suppressing atrial regional identity. We also uncover some of the signals responsible. The method holds promise as a tool to discover other novel organizers acting during development.

Discovering Alaska's Salmon: A Children's Activity Book.

Science.gov (United States)

Devaney, Laurel

This children's activity book helps students discover Alaska's salmon. Information is provided about salmon and where they live. The salmon life cycle and food chains are also discussed. Different kinds of salmon such as Chum Salmon, Chinook Salmon, Coho Salmon, Sockeye Salmon, and Pink Salmon are introduced, and various activities on salmon are…

On a New Technique for Discovering Variable Stars

Directory of Open Access Journals (Sweden)

Mironov A. V.

2003-12-01

Full Text Available A technique for discovering variable stars based on the calculation of the correlation coefficients is proposed. Applications of the technique are shown on the results of numerical experiments and on the Hipparcos photometric data.

Dominant Large-Scale Atmospheric Circulation Systems for the Extreme Precipitation over the Western Sichuan Basin in Summer 2013

Directory of Open Access Journals (Sweden)

Yamin Hu

2015-01-01

Full Text Available The western Sichuan Basin (WSB is a rainstorm center influenced by complicated factors such as topography and circulation. Based on multivariable empirical orthogonal function technique for extreme precipitation processes (EPP in WSB in 2013, this study reveals the dominant circulation patterns. Results indicate that the leading modes are characterized by “Saddle” and “Sandwich” structures, respectively. In one mode, a TC from the South China Sea (SCS converts into the inverted trough and steers warm moist airflow northward into the WSB. At the same time, WPSH extends westward over the Yangtze River and conveys a southeasterly warm humid flow. In the other case, WPSH is pushed westward by TC in the Western Pacific and then merges with an anomalous anticyclone over SCS. The anomalous anticyclone and WPSH form a conjunction belt and convey the warm moist southwesterly airflow to meet with the cold flow over the WSB. The configurations of WPSH and TC in the tropic and the blocking and trough in the midhigh latitudes play important roles during the EPPs over the WSB. The persistence of EPPs depends on the long-lived large-scale circulation configuration steady over the suitable positions.

Teaching Large Sections of a Business Communication Course: A Multicase Study

Science.gov (United States)

Wright, Carol

2017-01-01

The purpose of this research is to examine specific examples of how business communication courses are delivered in large, face-to-face university classes to discover implications of these large courses. This case study reviewed four classes from two different midsized universities whose classes range from 48 to 300 students. Findings suggest…

Rainfall Variability and the Recent Climate Extremes in Nigeria ...

African Journals Online (AJOL)

Recently, large and extended weather and climate extremes were recorded in different parts of the country, causing significant socio-economic impacts. Weather patterns affecting the country are driven by the northward and southward movement of the Inter-Tropical Discontinuity (ITD) as well as developments within the ...

Temperature extremes reduce seagrass growth and induce mortality

International Nuclear Information System (INIS)

Collier, C.J.; Waycott, M.

2014-01-01

Highlights: • Temperature extremes occur during low tide in shallow seagrass meadows. • The effects of temperature extremes were tested experimentally at 35 °C, 40 °C and 43 °C. • 40 °C was a critical threshold with a large impact on growth and mortality. • At 43 °C there was complete mortality after 2–3 days. • Lower light conditions (e.g. poor water quality) led to a greater negative impact. - Abstract: Extreme heating (up to 43 °C measured from five-year temperature records) occurs in shallow coastal seagrass meadows of the Great Barrier Reef at low tide. We measured effective quantum yield (ϕ PSII ), growth, senescence and mortality in four tropical seagrasses to experimental short-duration (2.5 h) spikes in water temperature to 35 °C, 40 °C and 43 °C, for 6 days followed by one day at ambient temperature. Increasing temperature to 35 °C had positive effects on ϕ PSII (the magnitude varied between days and was highly correlated with PPFD), with no effects on growth or mortality. 40 °C represented a critical threshold as there were strong species differences and there was a large impact on growth and mortality. At 43 °C there was complete mortality after 2–3 days. These findings indicate that increasing duration (more days in a row) of thermal events above 40 °C is likely to affect the ecological function of tropical seagrass meadows

Accelerating Large Data Analysis By Exploiting Regularities

Science.gov (United States)

Moran, Patrick J.; Ellsworth, David

2003-01-01

We present techniques for discovering and exploiting regularity in large curvilinear data sets. The data can be based on a single mesh or a mesh composed of multiple submeshes (also known as zones). Multi-zone data are typical to Computational Fluid Dynamics (CFD) simulations. Regularities include axis-aligned rectilinear and cylindrical meshes as well as cases where one zone is equivalent to a rigid-body transformation of another. Our algorithms can also discover rigid-body motion of meshes in time-series data. Next, we describe a data model where we can utilize the results from the discovery process in order to accelerate large data visualizations. Where possible, we replace general curvilinear zones with rectilinear or cylindrical zones. In rigid-body motion cases we replace a time-series of meshes with a transformed mesh object where a reference mesh is dynamically transformed based on a given time value in order to satisfy geometry requests, on demand. The data model enables us to make these substitutions and dynamic transformations transparently with respect to the visualization algorithms. We present results with large data sets where we combine our mesh replacement and transformation techniques with out-of-core paging in order to achieve significant speed-ups in analysis.

How to Discover the Rogers–Ramanujan Identities

Indian Academy of Sciences (India)

IAS Admin

The purpose of this article is to introduce you to the. Rogers–Ramanujan identities, by discussing an approach to discover them. When you see that they appear from a very simple generalization of the simplest possible in- finite continued fraction, that in turn is related to the celebrated Fibonacci sequence, perhaps you may ...

Rapid adaptation of microalgae to bodies of water with extreme pollution from uranium mining: An explanation of how mesophilic organisms can rapidly colonise extremely toxic environments

Energy Technology Data Exchange (ETDEWEB)

García-Balboa, C.; Baselga-Cervera, B. [Genetica, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid (Spain); García-Sanchez, A.; Igual, J.M. [Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA-CSIC), PO Box 257, 37071 Salamanca (Spain); Lopez-Rodas, V. [Genetica, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid (Spain); Costas, E., E-mail: ecostas@vet.ucm.es [Genetica, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid (Spain)

2013-11-15

Highlights: •Some microalgae species survive to extreme environments in ponds of residual waters from uranium mining. •Adaptation of microalgae to U arose very fast. •Spontaneous mutations that confer large adaptive value were able to produce the adaptation to residual waters of U mining. •Adaptation to more extreme waters of U mining is only possible after the recombination subsequent to sexual mating. •Resistant microalgae bio-adsorbs uranium to the cell wall and internalises uranium inside the cytoplasm. -- Abstract: Extreme environments may support communities of microalgae living at the limits of their tolerance. It is usually assumed that these extreme environments are inhabited by extremophile species. However, global anthropogenic environmental changes are generating new extreme environments, such as mining-effluent pools of residual waters from uranium mining with high U levels, acidity and radioactivity in Salamanca (Spain). Certain microalgal species have rapidly adapted to these extreme waters (uranium mining in this area began in 1960). Experiments have demonstrated that physiological acclimatisation would be unable to achieve adaptation. In contrast, rapid genetic adaptation was observed in waters ostensibly lethal to microalgae by means of rare spontaneous mutations that occurred prior to the exposure to effluent waters from uranium mining. However, adaptation to the most extreme conditions was only possible after recombination through sexual mating because adaptation requires more than one mutation. Microalgae living in extreme environments could be the descendants of pre-selective mutants that confer significant adaptive value to extreme contamination. These “lucky mutants” could allow for the evolutionary rescue of populations faced with rapid environmental change.

Rapid adaptation of microalgae to bodies of water with extreme pollution from uranium mining: An explanation of how mesophilic organisms can rapidly colonise extremely toxic environments

International Nuclear Information System (INIS)

García-Balboa, C.; Baselga-Cervera, B.; García-Sanchez, A.; Igual, J.M.; Lopez-Rodas, V.; Costas, E.

2013-01-01

Highlights: •Some microalgae species survive to extreme environments in ponds of residual waters from uranium mining. •Adaptation of microalgae to U arose very fast. •Spontaneous mutations that confer large adaptive value were able to produce the adaptation to residual waters of U mining. •Adaptation to more extreme waters of U mining is only possible after the recombination subsequent to sexual mating. •Resistant microalgae bio-adsorbs uranium to the cell wall and internalises uranium inside the cytoplasm. -- Abstract: Extreme environments may support communities of microalgae living at the limits of their tolerance. It is usually assumed that these extreme environments are inhabited by extremophile species. However, global anthropogenic environmental changes are generating new extreme environments, such as mining-effluent pools of residual waters from uranium mining with high U levels, acidity and radioactivity in Salamanca (Spain). Certain microalgal species have rapidly adapted to these extreme waters (uranium mining in this area began in 1960). Experiments have demonstrated that physiological acclimatisation would be unable to achieve adaptation. In contrast, rapid genetic adaptation was observed in waters ostensibly lethal to microalgae by means of rare spontaneous mutations that occurred prior to the exposure to effluent waters from uranium mining. However, adaptation to the most extreme conditions was only possible after recombination through sexual mating because adaptation requires more than one mutation. Microalgae living in extreme environments could be the descendants of pre-selective mutants that confer significant adaptive value to extreme contamination. These “lucky mutants” could allow for the evolutionary rescue of populations faced with rapid environmental change

Extreme cosmos

CERN Document Server

Gaensler, Bryan

2011-01-01

The universe is all about extremes. Space has a temperature 270°C below freezing. Stars die in catastrophic supernova explosions a billion times brighter than the Sun. A black hole can generate 10 million trillion volts of electricity. And hypergiants are stars 2 billion kilometres across, larger than the orbit of Jupiter. Extreme Cosmos provides a stunning new view of the way the Universe works, seen through the lens of extremes: the fastest, hottest, heaviest, brightest, oldest, densest and even the loudest. This is an astronomy book that not only offers amazing facts and figures but also re

GLIESE 581D IS THE FIRST DISCOVERED TERRESTRIAL-MASS EXOPLANET IN THE HABITABLE ZONE

International Nuclear Information System (INIS)

Wordsworth, Robin D.; Forget, Francois; Millour, Ehouarn; Charnay, Benjamin; Madeleine, Jean-Baptiste; Selsis, Franck

2011-01-01

It has been suggested that the recently discovered exoplanet GJ581d might be able to support liquid water due to its relatively low mass and orbital distance. However, GJ581d receives 35% less stellar energy than Mars and is probably locked in tidal resonance, with extremely low insolation at the poles and possibly a permanent night side. Under such conditions, it is unknown whether any habitable climate on the planet would be able to withstand global glaciation and/or atmospheric collapse. Here we present three-dimensional climate simulations which demonstrate that GJ581d will have a stable atmosphere and surface liquid water for a wide range of plausible cases, making it the first confirmed super-Earth (exoplanet of 2-10 Earth masses) in the habitable zone. We find that atmospheres with over 10 bar CO 2 and varying amounts of background gas (e.g., N 2 ) yield global mean temperatures above 0 0 C for both land and ocean-covered surfaces. Based on the emitted IR radiation calculated by the model, we propose observational tests that will allow these cases to be distinguished from other possible scenarios in the future.

Discovering frequently recurring movement sequences in team-sport athlete spatiotemporal data.

Science.gov (United States)

Sweeting, Alice J; Aughey, Robert J; Cormack, Stuart J; Morgan, Stuart

2017-12-01

Athlete external load is typically analysed from predetermined movement thresholds. The combination of movement sequences and differences in these movements between playing positions is also currently unknown. This study developed a method to discover the frequently recurring movement sequences across playing position during matches. The external load of 12 international female netball athletes was collected by a local positioning system during four national-level matches. Velocity, acceleration and angular velocity were calculated from positional (X, Y) data, clustered via one-dimensional k-means and assigned a unique alphabetic label. Combinations of velocity, acceleration and angular velocity movement were compared using the Levenshtein distance and similarities computed by the longest common substring problem. The contribution of each movement sequence, according to playing position and relative to the wider data set, was then calculated via the Minkowski distance. A total of 10 frequently recurring combinations of movement were discovered, regardless of playing position. Only the wing attack, goal attack and goal defence playing positions are closely related. We developed a technique to discover the movement sequences, according to playing position, performed by elite netballers. This methodology can be extended to discover the frequently recurring movements within other team sports and across levels of competition.

Extremal black hole/CFT correspondence in (gauged) supergravities

International Nuclear Information System (INIS)

Chow, David D. K.; Cvetic, M.; Lue, H.; Pope, C. N.

2009-01-01

We extend the investigation of the recently proposed Kerr/conformal field theory correspondence to large classes of rotating black hole solutions in gauged and ungauged supergravities. The correspondence, proposed originally for four-dimensional Kerr black holes, asserts that the quantum states in the near-horizon region of an extremal rotating black hole are holographically dual to a two-dimensional chiral theory whose Virasoro algebra arises as an asymptotic symmetry of the near-horizon geometry. In fact, in dimension D there are [(D-1)/2] commuting Virasoro algebras. We consider a general canonical class of near-horizon geometries in arbitrary dimension D, and show that in any such metric the [(D-1)/2] central charges each imply, via the Cardy formula, a microscopic entropy that agrees with the Bekenstein-Hawking entropy of the associated extremal black hole. In the remainder of the paper we show for most of the known rotating black hole solutions of gauged supergravity, and for the ungauged supergravity solutions with four charges in D=4 and three charges in D=5, that their extremal near-horizon geometries indeed lie within the canonical form. This establishes that, in all these examples, the microscopic entropies of the dual conformal field theories agree with the Bekenstein-Hawking entropies of the extremal rotating black holes.

Norovirus Genetic Diversity – from within patient viral evolution to global distribution : Genetische diversiteit van norovirus – van virale evolutie binnen patiënten tot wereldwijde verspreiding

NARCIS (Netherlands)

J. van Beek (Janko)

2018-01-01

textabstractNoroviruses belong to the family of Caliciviridae and cause acute gastroenteritis. The genetic diversity within the genus Norovirus is extremely large and novel genotypes, recombinants within and between genotypes, and antigenic drift variants are regularly discovered. The distribution

Arctic daily temperature and precipitation extremes: Observed and simulated physical behavior

Science.gov (United States)

Glisan, Justin Michael

Simulations using a six-member ensemble of Pan-Arctic WRF (PAW) were produced on two Arctic domains with 50-km resolution to analyze precipitation and temperature extremes for various periods. The first study used a domain developed for the Regional Arctic Climate Model (RACM). Initial simulations revealed deep atmospheric circulation biases over the northern Pacific Ocean, manifested in pressure, geopotential height, and temperature fields. Possible remedies to correct these large biases, such as modifying the physical domain or using different initial/boundary conditions, were unsuccessful. Spectral (interior) nudging was introduced as a way of constraining the model to be more consistent with observed behavior. However, such control over numerical model behavior raises concerns over how much nudging may affect unforced variability and extremes. Strong nudging may reduce or filter out extreme events, since the nudging pushes the model toward a relatively smooth, large-scale state. The question then becomes---what is the minimum spectral nudging needed to correct biases while not limiting the simulation of extreme events? To determine this, we use varying degrees of spectral nudging, using WRF's standard nudging as a reference point during January and July 2007. Results suggest that there is a marked lack of sensitivity to varying degrees of nudging. Moreover, given that nudging is an artificial forcing applied in the model, an important outcome of this work is that nudging strength apparently can be considerably smaller than WRF's standard strength and still produce reliable simulations. In the remaining studies, we used the same PAW setup to analyze daily precipitation extremes simulated over a 19-year period on the CORDEX Arctic domain for winter and summer. We defined these seasons as the three-month period leading up to and including the climatological sea ice maximum and minimum, respectively. Analysis focused on four North American regions defined using

GraMi: Generalized Frequent Pattern Mining in a Single Large Graph

KAUST Repository

Saeedy, Mohammed El

2011-11-01

Mining frequent subgraphs is an important operation on graphs. Most existing work assumes a database of many small graphs, but modern applications, such as social networks, citation graphs or protein-protein interaction in bioinformatics, are modeled as a single large graph. Interesting interactions in such applications may be transitive (e.g., friend of a friend). Existing methods, however, search for frequent isomorphic (i.e., exact match) subgraphs and cannot discover many useful patterns. In this paper the authors propose GRAMI, a framework that generalizes frequent subgraph mining in a large single graph. GRAMI discovers frequent patterns. A pattern is a graph where edges are generalized to distance-constrained paths. Depending on the definition of the distance function, many instantiations of the framework are possible. Both directed and undirected graphs, as well as multiple labels per vertex, are supported. The authors developed an efficient implementation of the framework that models the frequency resolution phase as a constraint satisfaction problem, in order to avoid the costly enumeration of all instances of each pattern in the graph. The authors also implemented CGRAMI, a version that supports structural and semantic constraints; and AGRAMI, an approximate version that supports very large graphs. The experiments on real data demonstrate that the authors framework is up to 3 orders of magnitude faster and discovers more interesting patterns than existing approaches.

A new screening method for discovering antibacterial agents from ...

African Journals Online (AJOL)

A new screening method for discovering antibacterial agents from filamentous fungi. ... African Journal of Biotechnology ... Keywords: Drug-resistant bacterial pathogens, novel antibiotics; screening method, filamentous fungi products ...

Further outlooks: extremely uncomfortable; Die weiteren Aussichten: extrem ungemuetlich

Energy Technology Data Exchange (ETDEWEB)

Resenhoeft, T.

2006-07-01

Climate is changing extremely in the last decades. Scientists dealing with extreme weather, should not only stare at computer simulations. They have also to turn towards psyche, seriously personal experiences, knowing statistics, relativise supposed sensational reports and last not least collecting more data. (GL)

The National Extreme Events Data and Research Center (NEED)

Science.gov (United States)

Gulledge, J.; Kaiser, D. P.; Wilbanks, T. J.; Boden, T.; Devarakonda, R.

2014-12-01

The Climate Change Science Institute at Oak Ridge National Laboratory (ORNL) is establishing the National Extreme Events Data and Research Center (NEED), with the goal of transforming how the United States studies and prepares for extreme weather events in the context of a changing climate. NEED will encourage the myriad, distributed extreme events research communities to move toward the adoption of common practices and will develop a new database compiling global historical data on weather- and climate-related extreme events (e.g., heat waves, droughts, hurricanes, etc.) and related information about impacts, costs, recovery, and available research. Currently, extreme event information is not easy to access and is largely incompatible and inconsistent across web sites. NEED's database development will take into account differences in time frames, spatial scales, treatments of uncertainty, and other parameters and variables, and leverage informatics tools developed at ORNL (i.e., the Metadata Editor [1] and Mercury [2]) to generate standardized, robust documentation for each database along with a web-searchable catalog. In addition, NEED will facilitate convergence on commonly accepted definitions and standards for extreme events data and will enable integrated analyses of coupled threats, such as hurricanes/sea-level rise/flooding and droughts/wildfires. Our goal and vision is that NEED will become the premiere integrated resource for the general study of extreme events. References: [1] Devarakonda, Ranjeet, et al. "OME: Tool for generating and managing metadata to handle BigData." Big Data (Big Data), 2014 IEEE International Conference on. IEEE, 2014. [2] Devarakonda, Ranjeet, et al. "Mercury: reusable metadata management, data discovery and access system." Earth Science Informatics 3.1-2 (2010): 87-94.

Extreme morphologies of mantis shrimp larvae

Directory of Open Access Journals (Sweden)

Carolin Haug

Full Text Available ABSTRACT Larvae of stomatopods (mantis shrimps are generally categorized into four larval types: antizoea, pseudozoea (both representing early larval stages, alima and erichthus (the latter two representing later larval stages. These categories, however, do not reflect the existing morphological diversity of stomatopod larvae, which is largely unstudied. We describe here four previously unknown larval types with extreme morphologies. All specimens were found in the collections of the Zoological Museum, University of Copenhagen and were collected during the Danish Dana Expedition round the world 1928-30. These new larval types all represent erichthus-type larvae, especially differing in their shield morphologies. The shield morphology ranges from almost spherical to rather disc-like, with sometimes extremely elongated spines, but only a general systematic assignment of the larvae was possible. Further investigations of these larvae are crucial to understand their life habits and ecological impact, especially as stomatopod and other crustacean larvae might have a much more important position in the marine ecosystems than their corresponding adults.

Comparison and Evolution of Extreme Rainfall-Induced Landslides in Taiwan

Directory of Open Access Journals (Sweden)

Chunhung WU

2017-11-01

Full Text Available This study analyzed the characteristics of, and locations prone to, extreme rainfall-induced landslides in three watersheds in Taiwan, as well as the long-term evolution of landslides in the Laonong River watershed (LRW, based on multiannual landslide inventories during 2003–2014. Extreme rainfall-induced landslides were centralized beside sinuous or meandering reaches, especially those with large sediment deposition. Landslide-prone strata during extreme rainfall events were sandstone and siltstone. Large-scale landslides were likely to occur when the maximum 6-h accumulated rainfall exceeded 420 mm. All of the large-scale landslides induced by short-duration and high-intensity rainfall developed from historical small-scale landslides beside the sinuous or meandering reaches or in the source area of rivers. However, most of the large-scale landslides induced by long-duration and high-intensity rainfall were new but were still located beside sinuous or meandering reaches or near the source. The frequency density of landslides under long-duration and high-intensity rainfall was larger by one order than those under short-duration rainfall, and the β values in the landslide frequency density-area analysis ranged from 1.22 to 1.348. The number of downslope landslides was three times larger than those of midslope and upslope landslides. The extreme rainfall-induced landslides occurred in the erosion gullies upstream of the watersheds, whereas those beside rivers were downstream. Analysis of the long-term evolution of landslides in the LRW showed that the geological setting, sinuousness of reaches, and sediment yield volume determined their location and evolution. Small-scale landslides constituted 71.9–96.2% of the total cases from 2003 to 2014, and were more easily induced after Typhoon Morakot (2009. The frequency density of landslides after Morakot was greater by one order than before, with 61% to 68% of total landslides located in the

Extreme Events in China under Climate Change: Uncertainty and related impacts (CSSP-FOREX)

Science.gov (United States)

Leckebusch, Gregor C.; Befort, Daniel J.; Hodges, Kevin I.

2016-04-01

Suitable adaptation strategies or the timely initiation of related mitigation efforts in East Asia will strongly depend on robust and comprehensive information about future near-term as well as long-term potential changes in the climate system. Therefore, understanding the driving mechanisms associated with the East Asian climate is of major importance. The FOREX project (Fostering Regional Decision Making by the Assessment of Uncertainties of Future Regional Extremes and their Linkage to Global Climate System Variability for China and East Asia) focuses on the investigation of extreme wind and rainfall related events over Eastern Asia and their possible future changes. Here, analyses focus on the link between local extreme events and their driving weather systems. This includes the coupling between local rainfall extremes and tropical cyclones, the Meiyu frontal system, extra-tropical teleconnections and monsoonal activity. Furthermore, the relation between these driving weather systems and large-scale variability modes, e.g. NAO, PDO, ENSO is analysed. Thus, beside analysing future changes of local extreme events, the temporal variability of their driving weather systems and related large-scale variability modes will be assessed in current CMIP5 global model simulations to obtain more robust results. Beyond an overview of FOREX itself, first results regarding the link between local extremes and their steering weather systems based on observational and reanalysis data are shown. Special focus is laid on the contribution of monsoonal activity, tropical cyclones and the Meiyu frontal system on the inter-annual variability of the East Asian summer rainfall.

Evaluation of extreme temperature events in northern Spain based on process control charts

Science.gov (United States)

Villeta, M.; Valencia, J. L.; Saá, A.; Tarquis, A. M.

2018-02-01

Extreme climate events have recently attracted the attention of a growing number of researchers because these events impose a large cost on agriculture and associated insurance planning. This study focuses on extreme temperature events and proposes a new method for their evaluation based on statistical process control tools, which are unusual in climate studies. A series of minimum and maximum daily temperatures for 12 geographical areas of a Spanish region between 1931 and 2009 were evaluated by applying statistical process control charts to statistically test whether evidence existed for an increase or a decrease of extreme temperature events. Specification limits were determined for each geographical area and used to define four types of extreme anomalies: lower and upper extremes for the minimum and maximum anomalies. A new binomial Markov extended process that considers the autocorrelation between extreme temperature events was generated for each geographical area and extreme anomaly type to establish the attribute control charts for the annual fraction of extreme days and to monitor the occurrence of annual extreme days. This method was used to assess the significance of changes and trends of extreme temperature events in the analysed region. The results demonstrate the effectiveness of an attribute control chart for evaluating extreme temperature events. For example, the evaluation of extreme maximum temperature events using the proposed statistical process control charts was consistent with the evidence of an increase in maximum temperatures during the last decades of the last century.

(When and where) Do extreme climate events trigger extreme ecosystem responses? - Development and initial results of a holistic analysis framework

Science.gov (United States)

Hauber, Eva K.; Donner, Reik V.

2015-04-01

In the context of ongoing climate change, extremes are likely to increase in magnitude and frequency. One of the most important consequences of these changes is that the associated ecological risks and impacts are potentially rising as well. In order to better anticipate and understand these impacts, it therefore becomes more and more crucial to understand the general connection between climate extremes and the response and functionality of ecosystems. Among other region of the world, Europe presents an excellent test case for studies concerning the interaction between climate and biosphere, since it lies in the transition region between cold polar and warm tropical air masses and thus covers a great variety of different climatic zones and associated terrestrial ecosystems. The large temperature differences across the continent make this region particularly interesting for investigating the effects of climate change on biosphere-climate interactions. However, previously used methods for defining an extreme event typically disregard the necessity of taking seasonality as well as seasonal variance appropriately into account. Furthermore, most studies have focused on the impacts of individual extreme events instead of considering a whole inventory of extremes with their respective spatio-temporal extents. In order to overcome the aforementioned research gaps, this work introduces a new approach to studying climate-biosphere interactions associated with extreme events, which comprises three consecutive steps: (1) Since Europe exhibits climatic conditions characterized by marked seasonality, a novel method is developed to define extreme events taking into account the seasonality in all quantiles of the probability distribution of the respective variable of interest. This is achieved by considering kernel density estimates individually for each observation date during the year, including the properly weighted information from adjacent dates. By this procedure, we obtain

Null infinity and extremal horizons in AdS-CFT

International Nuclear Information System (INIS)

Hickling, Andrew; Wiseman, Toby; Lucietti, James

2015-01-01

We consider AdS gravity duals to CFT on background spacetimes with a null infinity. Null infinity on the conformal boundary may extend to an extremal horizon in the bulk. For example it does so for Poincaré–AdS, although does not for planar Schwarzschild–AdS. If null infinity does extend into an extremal horizon in the bulk, we show that the bulk near-horizon geometry is determined by the geometry of the boundary null infinity. Hence the ‘infra-red’ geometry of the bulk is fixed by the large scale behaviour of the CFT spacetime. In addition the boundary stress tensor must have a particular decay at null infinity. As an application, we argue that for CFT on asymptotically flat backgrounds, any static bulk dual containing an extremal horizon extending from the boundary null infinity, must have the near-horizon geometry of Poincaré–AdS. We also discuss a class of boundary null infinity that cannot extend to a bulk extremal horizon, although we give evidence that they can extend to an analogous null surface in the bulk which possesses an associated scale-invariant ‘near-geometry’. (paper)

Asymmetric author-topic model for knowledge discovering of big data in toxicogenomics.

Science.gov (United States)

Chung, Ming-Hua; Wang, Yuping; Tang, Hailin; Zou, Wen; Basinger, John; Xu, Xiaowei; Tong, Weida

2015-01-01

The advancement of high-throughput screening technologies facilitates the generation of massive amount of biological data, a big data phenomena in biomedical science. Yet, researchers still heavily rely on keyword search and/or literature review to navigate the databases and analyses are often done in rather small-scale. As a result, the rich information of a database has not been fully utilized, particularly for the information embedded in the interactive nature between data points that are largely ignored and buried. For the past 10 years, probabilistic topic modeling has been recognized as an effective machine learning algorithm to annotate the hidden thematic structure of massive collection of documents. The analogy between text corpus and large-scale genomic data enables the application of text mining tools, like probabilistic topic models, to explore hidden patterns of genomic data and to the extension of altered biological functions. In this paper, we developed a generalized probabilistic topic model to analyze a toxicogenomics dataset that consists of a large number of gene expression data from the rat livers treated with drugs in multiple dose and time-points. We discovered the hidden patterns in gene expression associated with the effect of doses and time-points of treatment. Finally, we illustrated the ability of our model to identify the evidence of potential reduction of animal use.

Asymmetric author-topic model for knowledge discovering of big data in toxicogenomics

Directory of Open Access Journals (Sweden)

Ming-Hua eChung

2015-04-01

Full Text Available The advancement of high-throughput screening technologies facilitates the generation of massive amount of biological data, a big data phenomena in biomedical science. Yet, researchers still heavily rely on keyword search and/or literature review to navigate the databases and analyses are often done in rather small-scale. As a result, the rich information of a database has not been fully utilized, particularly for the information embedded in the interactive nature between data points that are largely ignored and buried. For the past ten years, probabilistic topic modeling has been recognized as an effective machine learning algorithm to annotate the hidden thematic structure of massive collection of documents. The analogy between text corpus and large-scale genomic data enables the application of text mining tools, like probabilistic topic models, to explore hidden patterns of genomic data and to the extension of altered biological functions. In this paper, we developed a generalized probabilistic topic model to analyze a toxicogenomics dataset that consists of a large number of gene expression data from the rat livers treated with drugs in multiple dose and time-points. We discovered the hidden patterns in gene expression associated with the effect of doses and time-points of treatment. Finally, we illustrated the ability of our model to identify the evidence of potential reduction of animal use.

Modeling spatial processes with unknown extremal dependence class

KAUST Repository

Huser, Raphaël G.

2017-03-17

Many environmental processes exhibit weakening spatial dependence as events become more extreme. Well-known limiting models, such as max-stable or generalized Pareto processes, cannot capture this, which can lead to a preference for models that exhibit a property known as asymptotic independence. However, weakening dependence does not automatically imply asymptotic independence, and whether the process is truly asymptotically (in)dependent is usually far from clear. The distinction is key as it can have a large impact upon extrapolation, i.e., the estimated probabilities of events more extreme than those observed. In this work, we present a single spatial model that is able to capture both dependence classes in a parsimonious manner, and with a smooth transition between the two cases. The model covers a wide range of possibilities from asymptotic independence through to complete dependence, and permits weakening dependence of extremes even under asymptotic dependence. Censored likelihood-based inference for the implied copula is feasible in moderate dimensions due to closed-form margins. The model is applied to oceanographic datasets with ambiguous true limiting dependence structure.

Discover the Cosmos - Bringing Cutting Edge Science to Schools across Europe

Science.gov (United States)

Doran, Rosa

2015-03-01

The fast growing number of science data repositories is opening enormous possibilities to scientists all over the world. The emergence of citizen science projects is engaging in science discovery a large number of citizens globally. Astronomical research is now a possibility to anyone having a computer and some form of data access. This opens a very interesting and strategic possibility to engage large audiences in the making and understanding of science. On another perspective it would be only natural to imagine that soon enough data mining will be an active part of the academic path of university or even secondary schools students. The possibility is very exciting but the road not very promising. Even in the most developed nations, where all schools are equipped with modern ICT facilities the use of such possibilities is still a very rare episode. The Galileo Teacher Training Program GTTP, a legacy of IYA2009, is participating in some of the most emblematic projects funded by the European Commission and targeting modern tools, resources and methodologies for science teaching. One of this projects is Discover the Cosmos which is aiming to target this issue by empowering educators with the necessary skills to embark on this innovative path: teaching science while doing science.

Scientists discover planetary system similar to our own

CERN Multimedia

2003-01-01

'An international team of scientists has discovered a planet and star that may share the same relationship as Jupiter and our Sun, the closest comparison that researchers have found since they began their search for extra-solar planets nearly a decade ago' (1 page).

Prevalence of lower extremity venous duplication

Directory of Open Access Journals (Sweden)

Simpson William

2010-01-01

Full Text Available Purpose: This retrospective study was performed to determine the prevalence of lower extremity venous duplication using duplex ultrasound in the patient population of a large urban medical center. Materials and Methods: The reports of all lower extremity venous ultrasound examinations performed at our institution between January 1, 2002 and December 31, 2002 were reviewed. Ultrasound examinations that were performed for purposes other than the detection of lower extremity deep vein thrombosis were excluded. The prevalence of duplication and its specific location were recorded. In addition, the prevalence of thrombus and its specific location were also recorded. Results: A total of 3118 exams were performed in 2664 patients. Of the 2664 patients, 2311 had only one examination performed during the study period; 353 patients had more than one examination performed. We found that 10.1% of patients (270/2664 had at least one venous segment duplicated and 5.4% of patients (143/2664 had a thrombus in at least one venous segment. There was a statistically significant difference in the prevalence of both duplication and thrombus with a change in venous segment. Only 0.4% of patients (11/2664 had thrombus within a duplicated segment. Of those who had more than one examination performed, 15.3% (54/353 had the same venous segment(s seen on one examination but not another. Conclusion: Lower extremity venous duplication is a frequent anatomic variant that is seen in 10.1% of patients, but it may not be as common as is generally believed. It can result in a false negative result for deep vein thrombosis.

Overview of the biology of extreme events

Science.gov (United States)

Gutschick, V. P.; Bassirirad, H.

2008-12-01

Extreme events have, variously, meteorological origins as in heat waves or precipitation extremes, or biological origins as in pest and disease eruptions (or tectonic, earth-orbital, or impact-body origins). Despite growing recognition that these events are changing in frequency and intensity, a universal model of ecological responses to these events is slow to emerge. Extreme events, negative and positive, contrast with normal events in terms of their effects on the physiology, ecology, and evolution of organisms, hence also on water, carbon, and nutrient cycles. They structure biogeographic ranges and biomes, almost surely more than mean values often used to define biogeography. They are challenging to study for obvious reasons of field-readiness but also because they are defined by sequences of driving variables such as temperature, not point events. As sequences, their statistics (return times, for example) are challenging to develop, as also from the involvement of multiple environmental variables. These statistics are not captured well by climate models. They are expected to change with climate and land-use change but our predictive capacity is currently limited. A number of tools for description and analysis of extreme events are available, if not widely applied to date. Extremes for organisms are defined by their fitness effects on those organisms, and are specific to genotypes, making them major agents of natural selection. There is evidence that effects of extreme events may be concentrated in an extended recovery phase. We review selected events covering ranges of time and magnitude, from Snowball Earth to leaf functional loss in weather events. A number of events, such as the 2003 European heat wave, evidence effects on water and carbon cycles over large regions. Rising CO2 is the recent extreme of note, for its climatic effects and consequences for growing seasons, transpiration, etc., but also directly in its action as a substrate of photosynthesis

Scientists discover how deadly fungal microbes enter host cells

OpenAIRE

Whyte, Barry James

2010-01-01

A research team led by scientists at the Virginia Bioinformatics Institute at Virginia Tech has discovered a fundamental entry mechanism that allows dangerous fungal microbes to infect plants and cause disease.

New options for vascularized bone reconstruction in the upper extremity.

Science.gov (United States)

Houdek, Matthew T; Wagner, Eric R; Wyles, Cody C; Nanos, George P; Moran, Steven L

2015-02-01

Originally described in the 1970s, vascularized bone grafting has become a critical component in the treatment of bony defects and non-unions. Although well established in the lower extremity, recent years have seen many novel techniques described to treat a variety of challenging upper extremity pathologies. Here the authors review the use of different techniques of vascularized bone grafts for the upper extremity bone pathologies. The vascularized fibula remains the gold standard for the treatment of large bone defects of the humerus and forearm, while also playing a role in carpal reconstruction; however, two other important options for larger defects include the vascularized scapula graft and the Capanna technique. Smaller upper extremity bone defects and non-unions can be treated with the medial femoral condyle (MFC) free flap or a vascularized rib transfer. In carpal non-unions, both pedicled distal radius flaps and free MFC flaps are viable options. Finally, in skeletally immature patients, vascularized fibular head epiphyseal transfer can provide growth potential in addition to skeletal reconstruction.

The genesis of the newly discovered giant Wuben magmatic Fe-Ti oxide deposit in the Emeishan Large Igneous Province: a product of the late-stage redistribution and sorting of crystal slurries

Science.gov (United States)

Bai, Zhong-Jie; Zhong, Hong; Zhu, Wei-Guang; Hu, Wen-Jun; Chen, Cai-Jie

2018-04-01

A giant Fe-Ti oxide deposit hosted by the Wuben mafic intrusion has recently been discovered in the Pan-Xi area of the Emeishan Large Igneous Province (ELIP). The evolved compositions of the gangue minerals within the Fe-Ti oxide ores indicate that they formed during later stages of magma differentiation than those within the neighboring Panzhihua intrusion or other ore-bearing intrusions in this area. The rocks from the Wuben intrusion and MZb of the Panzhihua intrusion contain compositionally similar silicate minerals and have similar titanomagnetite/ilmenite ratios, suggesting that the former is related to and probably connected to the latter by subsurface magmatic conduits. This indicates that unconsolidated minerals that formed in the MZb flowed as crystal slurries into the Wuben magma chamber during the later stages of evolution of the parental magma. The later secondary enrichment of Fe-Ti oxides by mechanical redistribution and the sorting of crystals as a result of density and size differences generated the Wuben massive Fe-Ti oxide bodies. The ilmenite was commonly saturated in the magma at late stage of differentiation in the ELIP, thereby the associated deposit contains much higher contents of ilmenite. This indicates that future exploration for Fe-Ti oxide mineralization in the ELIP should not merely focus on the lower parts of large layered intrusions but should also include nearby relatively small intrusions or even the upper parts of large intrusions, especially as ilmenite-enriched Fe-Ti oxide deposits may have greater economic value than ilmenite-poor deposits.

Multifractal Conceptualisation of Hydro-Meteorological Extremes

Science.gov (United States)

Tchiguirinskaia, I.; Schertzer, D.; Lovejoy, S.

2009-04-01

Hydrology and more generally sciences involved in water resources management, technological or operational developments face a fundamental difficulty: the extreme variability of hydro-meteorological fields. It clearly appears today that this variability is a function of the observation scale and yield hydro-meteorological hazards. Throughout the world, the development of multifractal theory offers new techniques for handling such non-classical variability over wide ranges of time and space scales. The resulting stochastic simulations with a very limited number of parameters well reproduce the long range dependencies and the clustering of rainfall extremes often yielding fat tailed (i.e., an algebraic type) probability distributions. The goal of this work was to investigate the ability of using very short or incomplete data records for reliable statistical predictions of the extremes. In particular we discuss how to evaluate the uncertainty in the empirical or semi-analytical multifractal outcomes. We consider three main aspects of the evaluation, such as the scaling adequacy, the multifractal parameter estimation error and the quantile estimation error. We first use the multiplicative cascade model to generate long series of multifractal data. The simulated samples had to cover the range of the universal multifractal parameters widely available in the scientific literature for the rainfall and river discharges. Using these long multifractal series and their sub-samples, we defined a metric for parameter estimation error. Then using the sets of estimated parameters, we obtained the quantile values for a range of excedance probabilities from 5% to 0.01%. Plotting the error bars on a quantile plot enable an approximation of confidence intervals that would be particularly important for the predictions of multifractal extremes. We finally illustrate the efficiency of such concept on its application to a large database (more than 16000 selected stations over USA and

An influence of extremal edges on boundary extension.

Science.gov (United States)

Hale, Ralph G; Brown, James M; McDunn, Benjamin A; Siddiqui, Aisha P

2015-08-01

Studies have shown that people consistently remember seeing more of a studied scene than was physically present (e.g., Intraub & Richardson Journal of Experimental Psychology: Learning, Memory, and Cognition, 15, 179-187, 1989). This scene memory error, known as boundary extension, has been suggested to occur due to an observer's failure to differentiate between the contributing sources of information, including the sensory input, amodal continuation beyond the view boundaries, and contextual associations with the main objects and depicted scene locations (Intraub, 2010). Here, "scenes" made of abstract shapes on random-dot backgrounds, previously shown to elicit boundary extension (McDunn, Siddiqui, & Brown Psychonomic Bulletin & Review, 21, 370-375, 2014), were compared with versions made with extremal edges (Palmer & Ghose Psychological Science, 19, 77-84, 2008) added to their borders, in order to examine how boundary extension is influenced when amodal continuation at the borders' view boundaries is manipulated in this way. Extremal edges were expected to reduce boundary extension as compared to the same scenes without them, because extremal edge boundaries explicitly indicate an image's end (i.e., they do not continue past the view boundary). A large and a small difference (16 % and 40 %) between the close and wide-angle views shown during the experiment were tested to examine the effects of both boundary extension and normalization with and without extremal edges. Images without extremal edges elicited typical boundary extension for the 16 % size change condition, whereas the 40 % condition showed signs of normalization. With extremal edges, a reduced amount of boundary extension occurred for the 16 % condition, and only normalization was found for the 40 % condition. Our findings support and highlight the importance of amodal continuation at the view boundaries as a component of boundary extension.

The Importance of Studying Past Extreme Floods to Prepare for Uncertain Future Extremes

Science.gov (United States)

Burges, S. J.

2016-12-01

Hoyt and Langbein, 1955 in their book `Floods' wrote: " ..meteorologic and hydrologic conditions will combine to produce superfloods of unprecedented magnitude. We have every reason to believe that in most rivers past floods may not be an accurate measure of ultimate flood potentialities. It is this superflood with which we are always most concerned". I provide several examples to offer some historical perspective on assessing extreme floods. In one example, flooding in the Miami Valley, OH in 1913 claimed 350 lives. The engineering and socio-economic challenges facing the Morgan Engineering Co in how to mitigate against future flood damage and loss of life when limited information was available provide guidance about ways to face an uncertain hydroclimate future, particularly one of a changed climate. A second example forces us to examine mixed flood populations and illustrates the huge uncertainty in assigning flood magnitude and exceedance probability to extreme floods in such cases. There is large uncertainty in flood frequency estimates; knowledge of the total flood hydrograph, not the peak flood flow rate alone, is what is needed for hazard mitigation assessment or design. Some challenges in estimating the complete flood hydrograph in an uncertain future climate, including demands on hydrologic models and their inputs, are addressed.

Effects of Extreme Events on Arsenic Cycling in Salt Marshes

Science.gov (United States)

Northrup, Kristy; Capooci, Margaret; Seyfferth, Angelia L.

2018-03-01

Extreme events such as storm surges, intense precipitation, and supermoons cause anomalous and large fluctuations in water level in tidal salt marshes, which impacts the sediment biogeochemistry that dictates arsenic (As) cycling. In addition to changes in water level, which impacts soil redox potential, these extreme events may also change salinity due to freshwater inputs from precipitation or saltwater inputs due to surge. It is currently unknown how As mobility in tidal salt marshes will be impacted by extreme events, as fluctuations in salinity and redox potential may act synergistically to mobilize As. To investigate impacts of extreme events on As cycling in tidal salt marshes, we conducted a combined laboratory and field investigation. We monitored pore water and soil samples before, during, and after two extreme events: a supermoon lunar eclipse followed by a storm surge and precipitation induced by Hurricane Joaquin in fall 2015 at the St. Jones Reserve in Dover, Delaware, a representative tidal salt marsh in the Mid-Atlantic United States. We also conducted soil incubations of marsh sediments in batch and in flow-through experiments in which redox potential and/or salinity were manipulated. Field investigations showed that pore water As was inversely proportional to redox potential. During the extreme events, a distinct pulse of As was observed in the pore water with maximum salinity. Combined field and laboratory investigations revealed that this As pulse is likely due to rapid changes in salinity. These results have implications for As mobility in the face of extreme weather variability.

Top quark discovered

International Nuclear Information System (INIS)

Anon.

1995-01-01

Nine months after a careful announcement of tentative evidence for the long-awaited sixth 'top' quark, physicists from the CDF and DO experiments at Fermilab's Tevatron proton-antiproton collider declared on 2 March that they had finally discovered the top quark. Last year (June 1994, page 1), the CDF experiment at the Tevatron reported a dozen candidate top events. These, said CDF, had all the characteristics expected of top, but the difficulties of extracting the tiny signal from a trillion proton-antiproton collisions made them shy of claiming a discovery. For its part, the companion DO Tevatron experiment reported a few similar events but were even more guarded about their interpretation as top quarks. Just after these hesitant announcements, performance at the Tevatron improved dramatically last summer. After the commissioning of a new linear accelerator and a magnet realignment, the machine reached a new world record proton-antiproton collision luminosity of 1.28 x 10 31 per sq cm per s, ten times that originally planned. Data began to pour in at an unprecedented rate and the data sample grew to six trillion collisions. Luminosity has subsequently climbed to 1.7 x 10 31 . The top quark is the final letter in the alphabet of Standard Model particles. According to this picture, all matter is composed of six stronglyinteracting subnuclear particles, the quarks, and six weakly interacting particles, the leptons. Both sextets are neatly arranged as three pairs in order of increasing mass. The fifth quark, the 'beauty' or 'b' quark, was also discovered at Fermilab, back in 1977. Since then physicists have been eagerly waiting for the top to turn up, but have been frustrated by its heaviness - the top is some 40 times the mass of its 'beautiful' partner. Not only is the top quark the heaviest by far, but it is the only quark which has been actively hunted. After the quarry was glimpsed last year, the net has now been

The New HARSHAW Extremity Dosimeters for Gamma and Beta Ray Monitoring

International Nuclear Information System (INIS)

Fellinger, J.; Majewski, M.; Rotunda, J.; Tawi, R.

1997-01-01

Large personnel dosimetry services providing extremity monitoring with finger rings based on thermoluminescent detectors have long been looking for a practical method for automated reading including automated identification of the detectors.All existing methods are at least not very suitable for medical applications, particularly for surgery, due to the fact that cold sterilization is usually impossible.Bicron radiation Measurement Products developed in co-operation with the Austrian Research Centre Seibersdorf a new finger ring dosimeter DXT-RAD as a fast and economic solution for fully automated evaluation of extremity dosemeters. (authors)

[New population curves in spanish extremely preterm neonates].

Science.gov (United States)

García-Muñoz Rodrigo, F; García-Alix Pérez, A; Figueras Aloy, J; Saavedra Santana, P

2014-08-01

Most anthropometric reference data for extremely preterm infants used in Spain are outdated and based on non-Spanish populations, or are derived from small hospital-based samples that failed to include neonates of borderline viability. To develop gender-specific, population-based curves for birth weight, length, and head circumference in extremely preterm Caucasian infants, using a large contemporary sample size of Spanish singletons. Anthropometric data from neonates ≤ 28 weeks of gestational age were collected between January 2002 and December 2010 using the Spanish database SEN1500. Gestational age was estimated according to obstetric data (early pregnancy ultrasound). The data were analyzed with the SPSS.20 package, and centile tables were created for males and females using the Cole and Green LMS method. This study presents the first population-based growth curves for extremely preterm infants, including those of borderline viability, in Spain. A sexual dimorphism is evident for all of the studied parameters, starting at early gestation. These new gender-specific and population-based data could be useful for the improvement of growth assessments of extremely preterm infants in our country, for the development of epidemiological studies, for the evaluation of temporal trends, and for clinical or public health interventions seeking to optimize fetal growth. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

Fast Ss-Ilm a Computationally Efficient Algorithm to Discover Socially Important Locations

Science.gov (United States)

Dokuz, A. S.; Celik, M.

2017-11-01

Socially important locations are places which are frequently visited by social media users in their social media lifetime. Discovering socially important locations provide several valuable information about user behaviours on social media networking sites. However, discovering socially important locations are challenging due to data volume and dimensions, spatial and temporal calculations, location sparseness in social media datasets, and inefficiency of current algorithms. In the literature, several studies are conducted to discover important locations, however, the proposed approaches do not work in computationally efficient manner. In this study, we propose Fast SS-ILM algorithm by modifying the algorithm of SS-ILM to mine socially important locations efficiently. Experimental results show that proposed Fast SS-ILM algorithm decreases execution time of socially important locations discovery process up to 20 %.

FAST SS-ILM: A COMPUTATIONALLY EFFICIENT ALGORITHM TO DISCOVER SOCIALLY IMPORTANT LOCATIONS

Directory of Open Access Journals (Sweden)

A. S. Dokuz

2017-11-01

Full Text Available Socially important locations are places which are frequently visited by social media users in their social media lifetime. Discovering socially important locations provide several valuable information about user behaviours on social media networking sites. However, discovering socially important locations are challenging due to data volume and dimensions, spatial and temporal calculations, location sparseness in social media datasets, and inefficiency of current algorithms. In the literature, several studies are conducted to discover important locations, however, the proposed approaches do not work in computationally efficient manner. In this study, we propose Fast SS-ILM algorithm by modifying the algorithm of SS-ILM to mine socially important locations efficiently. Experimental results show that proposed Fast SS-ILM algorithm decreases execution time of socially important locations discovery process up to 20 %.

Earth's portfolio of extreme sediment transport events

Science.gov (United States)

Korup, Oliver

2012-05-01

Quantitative estimates of sediment flux and the global cycling of sediments from hillslopes to rivers, estuaries, deltas, continental shelves, and deep-sea basins have a long research tradition. In this context, extremely large and commensurately rare sediment transport events have so far eluded a systematic analysis. To start filling this knowledge gap I review some of the highest reported sediment yields in mountain rivers impacted by volcanic eruptions, earthquake- and storm-triggered landslide episodes, and catastrophic dam breaks. Extreme specific yields, defined here as those exceeding the 95th percentile of compiled data, are ~ 104 t km- 2 yr- 1 if averaged over 1 yr. These extreme yields vary by eight orders of magnitude, but systematically decay with reference intervals from minutes to millennia such that yields vary by three orders of magnitude for a given reference interval. Sediment delivery from natural dam breaks and pyroclastic eruptions dominate these yields for a given reference interval. Even if averaged over 102-103 yr, the contribution of individual disturbances may remain elevated above corresponding catchment denudation rates. I further estimate rates of sediment (re-)mobilisation by individual giant terrestrial and submarine mass movements. Less than 50 postglacial submarine mass movements have involved an equivalent of ~ 10% of the contemporary annual global flux of fluvial sediment to Earth's oceans, while mobilisation rates by individual events rival the decadal-scale sediment discharge from tectonically active orogens such as Taiwan or New Zealand. Sediment flushing associated with catastrophic natural dam breaks is non-stationary and shows a distinct kink at the last glacial-interglacial transition, owing to the drainage of very large late Pleistocene ice-marginal lakes. Besides emphasising the contribution of high-magnitude and low-frequency events to the global sediment cascade, these findings stress the importance of sediment storage

Starlight detectives how astronomers, inventors, and eccentrics discovered the modern universe

CERN Document Server

Hirshfeld, Alan

2014-01-01

NBC News “Top Science and Tech Books of the Year" selectionScientific American/FSG “Favorite Science Books of the Year" selectionNature.com “Top Reads of the Year" selectionKirkus Reviews “Best Books of the Year" selectionDiscover magazine “Top 5 Summer Read"“A masterful balance of science, history and rich narrative." —Discover magazine“Hirshfeld tells this climactic discovery of the expanding universe with great verve and sweep, as befits a story whose scope, characters and import leave

The Burmese python genome reveals the molecular basis for extreme adaptation in snakes.

Science.gov (United States)

Castoe, Todd A; de Koning, A P Jason; Hall, Kathryn T; Card, Daren C; Schield, Drew R; Fujita, Matthew K; Ruggiero, Robert P; Degner, Jack F; Daza, Juan M; Gu, Wanjun; Reyes-Velasco, Jacobo; Shaney, Kyle J; Castoe, Jill M; Fox, Samuel E; Poole, Alex W; Polanco, Daniel; Dobry, Jason; Vandewege, Michael W; Li, Qing; Schott, Ryan K; Kapusta, Aurélie; Minx, Patrick; Feschotte, Cédric; Uetz, Peter; Ray, David A; Hoffmann, Federico G; Bogden, Robert; Smith, Eric N; Chang, Belinda S W; Vonk, Freek J; Casewell, Nicholas R; Henkel, Christiaan V; Richardson, Michael K; Mackessy, Stephen P; Bronikowski, Anne M; Bronikowsi, Anne M; Yandell, Mark; Warren, Wesley C; Secor, Stephen M; Pollock, David D

2013-12-17

Snakes possess many extreme morphological and physiological adaptations. Identification of the molecular basis of these traits can provide novel understanding for vertebrate biology and medicine. Here, we study snake biology using the genome sequence of the Burmese python (Python molurus bivittatus), a model of extreme physiological and metabolic adaptation. We compare the python and king cobra genomes along with genomic samples from other snakes and perform transcriptome analysis to gain insights into the extreme phenotypes of the python. We discovered rapid and massive transcriptional responses in multiple organ systems that occur on feeding and coordinate major changes in organ size and function. Intriguingly, the homologs of these genes in humans are associated with metabolism, development, and pathology. We also found that many snake metabolic genes have undergone positive selection, which together with the rapid evolution of mitochondrial proteins, provides evidence for extensive adaptive redesign of snake metabolic pathways. Additional evidence for molecular adaptation and gene family expansions and contractions is associated with major physiological and phenotypic adaptations in snakes; genes involved are related to cell cycle, development, lungs, eyes, heart, intestine, and skeletal structure, including GRB2-associated binding protein 1, SSH, WNT16, and bone morphogenetic protein 7. Finally, changes in repetitive DNA content, guanine-cytosine isochore structure, and nucleotide substitution rates indicate major shifts in the structure and evolution of snake genomes compared with other amniotes. Phenotypic and physiological novelty in snakes seems to be driven by system-wide coordination of protein adaptation, gene expression, and changes in the structure of the genome.

Projections of Future Precipitation Extremes Over Europe: A Multimodel Assessment of Climate Simulations

Science.gov (United States)

Rajczak, Jan; Schär, Christoph

2017-10-01

Projections of precipitation and its extremes over the European continent are analyzed in an extensive multimodel ensemble of 12 and 50 km resolution EURO-CORDEX Regional Climate Models (RCMs) forced by RCP2.6, RCP4.5, and RCP8.5 (Representative Concentration Pathway) aerosol and greenhouse gas emission scenarios. A systematic intercomparison with ENSEMBLES RCMs is carried out, such that in total information is provided for an unprecedentedly large data set of 100 RCM simulations. An evaluation finds very reasonable skill for the EURO-CORDEX models in simulating temporal and geographical variations of (mean and heavy) precipitation at both horizontal resolutions. Heavy and extreme precipitation events are projected to intensify across most of Europe throughout the whole year. All considered models agree on a distinct intensification of extremes by often more than +20% in winter and fall and over central and northern Europe. A reduction of rainy days and mean precipitation in summer is simulated by a large majority of models in the Mediterranean area, but intermodel spread between the simulations is large. In central Europe and France during summer, models project decreases in precipitation but more intense heavy and extreme rainfalls. Comparison to previous RCM projections from ENSEMBLES reveals consistency but slight differences in summer, where reductions in southern European precipitation are not as pronounced as previously projected. The projected changes of the European hydrological cycle may have substantial impact on environmental and anthropogenic systems. In particular, the simulations indicate a rising probability of summertime drought in southern Europe and more frequent and intense heavy rainfall across all of Europe.

Asymmetrical Responses of Ecosystem Processes to Positive Versus Negative Precipitation Extremes: a Replicated Regression Experimental Approach

Science.gov (United States)

Felton, A. J.; Smith, M. D.

2016-12-01

Heightened climatic variability due to atmospheric warming is forecast to increase the frequency and severity of climate extremes. In particular, changes to interannual variability in precipitation, characterized by increases in extreme wet and dry years, are likely to impact virtually all terrestrial ecosystem processes. However, to date experimental approaches have yet to explicitly test how ecosystem processes respond to multiple levels of climatic extremity, limiting our understanding of how ecosystems will respond to forecast increases in the magnitude of climate extremes. Here we report the results of a replicated regression experimental approach, in which we imposed 9 and 11 levels of growing season precipitation amount and extremity in mesic grassland during 2015 and 2016, respectively. Each level corresponded to a specific percentile of the long-term record, which produced a large gradient of soil moisture conditions that ranged from extreme wet to extreme dry. In both 2015 and 2016, asymptotic responses to water availability were observed for soil respiration. This asymmetry was driven in part by transitions between soil moisture versus temperature constraints on respiration as conditions became increasingly dry versus increasingly wet. In 2015, aboveground net primary production (ANPP) exhibited asymmetric responses to precipitation that largely mirrored those of soil respiration. In total, our results suggest that in this mesic ecosystem, these two carbon cycle processes were more sensitive to extreme drought than to extreme wet years. Future work will assess ANPP responses for 2016, soil nutrient supply and physiological responses of the dominant plant species. Future efforts are needed to compare our findings across a diverse array of ecosystem types, and in particular how the timing and magnitude of precipitation events may modify the response of ecosystem processes to increasing magnitudes of precipitation extremes.

Adaptive Large Neighbourhood Search

DEFF Research Database (Denmark)

Røpke, Stefan

Large neighborhood search is a metaheuristic that has gained popularity in recent years. The heuristic repeatedly moves from solution to solution by first partially destroying the solution and then repairing it. The best solution observed during this search is presented as the final solution....... This tutorial introduces the large neighborhood search metaheuristic and the variant adaptive large neighborhood search that dynamically tunes parameters of the heuristic while it is running. Both heuristics belong to a broader class of heuristics that are searching a solution space using very large...... neighborhoods. The tutorial also present applications of the adaptive large neighborhood search, mostly related to vehicle routing problems for which the heuristic has been extremely successful. We discuss how the heuristic can be parallelized and thereby take advantage of modern desktop computers...

Discrete and structurally unique proteins (tāpirins) mediate attachment of extremely thermophilic Caldicellulosiruptor species to cellulose.

Science.gov (United States)

Blumer-Schuette, Sara E; Alahuhta, Markus; Conway, Jonathan M; Lee, Laura L; Zurawski, Jeffrey V; Giannone, Richard J; Hettich, Robert L; Lunin, Vladimir V; Himmel, Michael E; Kelly, Robert M

2015-04-24

A variety of catalytic and noncatalytic protein domains are deployed by select microorganisms to deconstruct lignocellulose. These extracellular proteins are used to attach to, modify, and hydrolyze the complex polysaccharides present in plant cell walls. Cellulolytic enzymes, often containing carbohydrate-binding modules, are key to this process; however, these enzymes are not solely responsible for attachment. Few mechanisms of attachment have been discovered among bacteria that do not form large polypeptide structures, called cellulosomes, to deconstruct biomass. In this study, bioinformatics and proteomics analyses identified unique, discrete, hypothetical proteins ("tāpirins," origin from Māori: to join), not directly associated with cellulases, that mediate attachment to cellulose by species in the noncellulosomal, extremely thermophilic bacterial genus Caldicellulosiruptor. Two tāpirin genes are located directly downstream of a type IV pilus operon in strongly cellulolytic members of the genus, whereas homologs are absent from the weakly cellulolytic Caldicellulosiruptor species. Based on their amino acid sequence, tāpirins are specific to these extreme thermophiles. Tāpirins are also unusual in that they share no detectable protein domain signatures with known polysaccharide-binding proteins. Adsorption isotherm and trans vivo analyses demonstrated the carbohydrate-binding module-like affinity of the tāpirins for cellulose. Crystallization of a cellulose-binding truncation from one tāpirin indicated that these proteins form a long β-helix core with a shielded hydrophobic face. Furthermore, they are structurally unique and define a new class of polysaccharide adhesins. Strongly cellulolytic Caldicellulosiruptor species employ tāpirins to complement substrate-binding proteins from the ATP-binding cassette transporters and multidomain extracellular and S-layer-associated glycoside hydrolases to process the carbohydrate content of lignocellulose. �

Statistical techniques for modeling extreme price dynamics in the energy market

International Nuclear Information System (INIS)

Mbugua, L N; Mwita, P N

2013-01-01

Extreme events have large impact throughout the span of engineering, science and economics. This is because extreme events often lead to failure and losses due to the nature unobservable of extra ordinary occurrences. In this context this paper focuses on appropriate statistical methods relating to a combination of quantile regression approach and extreme value theory to model the excesses. This plays a vital role in risk management. Locally, nonparametric quantile regression is used, a method that is flexible and best suited when one knows little about the functional forms of the object being estimated. The conditions are derived in order to estimate the extreme value distribution function. The threshold model of extreme values is used to circumvent the lack of adequate observation problem at the tail of the distribution function. The application of a selection of these techniques is demonstrated on the volatile fuel market. The results indicate that the method used can extract maximum possible reliable information from the data. The key attraction of this method is that it offers a set of ready made approaches to the most difficult problem of risk modeling.

Atomic and electronic structures of an extremely fragile liquid.

Science.gov (United States)

Kohara, Shinji; Akola, Jaakko; Patrikeev, Leonid; Ropo, Matti; Ohara, Koji; Itou, Masayoshi; Fujiwara, Akihiko; Yahiro, Jumpei; Okada, Junpei T; Ishikawa, Takehiko; Mizuno, Akitoshi; Masuno, Atsunobu; Watanabe, Yasuhiro; Usuki, Takeshi

2014-12-18

The structure of high-temperature liquids is an important topic for understanding the fragility of liquids. Here we report the structure of a high-temperature non-glass-forming oxide liquid, ZrO2, at an atomistic and electronic level. The Bhatia-Thornton number-number structure factor of ZrO2 does not show a first sharp diffraction peak. The atomic structure comprises ZrO5, ZrO6 and ZrO7 polyhedra with a significant contribution of edge sharing of oxygen in addition to corner sharing. The variety of large oxygen coordination and polyhedral connections with short Zr-O bond lifetimes, induced by the relatively large ionic radius of zirconium, disturbs the evolution of intermediate-range ordering, which leads to a reduced electronic band gap and increased delocalization in the ionic Zr-O bonding. The details of the chemical bonding explain the extremely low viscosity of the liquid and the absence of a first sharp diffraction peak, and indicate that liquid ZrO2 is an extremely fragile liquid.

Methodological Considerations in Estimation of Phenotype Heritability Using Genome-Wide SNP Data, Illustrated by an Analysis of the Heritability of Height in a Large Sample of African Ancestry Adults.

Directory of Open Access Journals (Sweden)

Fang Chen

Full Text Available Height has an extremely polygenic pattern of inheritance. Genome-wide association studies (GWAS have revealed hundreds of common variants that are associated with human height at genome-wide levels of significance. However, only a small fraction of phenotypic variation can be explained by the aggregate of these common variants. In a large study of African-American men and women (n = 14,419, we genotyped and analyzed 966,578 autosomal SNPs across the entire genome using a linear mixed model variance components approach implemented in the program GCTA (Yang et al Nat Genet 2010, and estimated an additive heritability of 44.7% (se: 3.7% for this phenotype in a sample of evidently unrelated individuals. While this estimated value is similar to that given by Yang et al in their analyses, we remain concerned about two related issues: (1 whether in the complete absence of hidden relatedness, variance components methods have adequate power to estimate heritability when a very large number of SNPs are used in the analysis; and (2 whether estimation of heritability may be biased, in real studies, by low levels of residual hidden relatedness. We addressed the first question in a semi-analytic fashion by directly simulating the distribution of the score statistic for a test of zero heritability with and without low levels of relatedness. The second question was addressed by a very careful comparison of the behavior of estimated heritability for both observed (self-reported height and simulated phenotypes compared to imputation R2 as a function of the number of SNPs used in the analysis. These simulations help to address the important question about whether today's GWAS SNPs will remain useful for imputing causal variants that are discovered using very large sample sizes in future studies of height, or whether the causal variants themselves will need to be genotyped de novo in order to build a prediction model that ultimately captures a large fraction of the

Transcript profiling of cytokinin action in Arabidopsis roots and shoots discovers largely similar but also organ-specific responses

Directory of Open Access Journals (Sweden)

Brenner Wolfram G

2012-07-01

Full Text Available Abstract Background The plant hormone cytokinin regulates growth and development of roots and shoots in opposite ways. In shoots it is a positive growth regulator whereas it inhibits growth in roots. It may be assumed that organ-specific regulation of gene expression is involved in these differential activities, but little is known about it. To get more insight into the transcriptional events triggered by cytokinin in roots and shoots, we studied genome-wide gene expression in cytokinin-treated and cytokinin-deficient roots and shoots. Results It was found by principal component analysis of the transcriptomic data that the immediate-early response to a cytokinin stimulus differs from the later response, and that the transcriptome of cytokinin-deficient plants is different from both the early and the late cytokinin induction response. A higher cytokinin status in the roots activated the expression of numerous genes normally expressed predominantly in the shoot, while a lower cytokinin status in the shoot reduced the expression of genes normally more active in the shoot to a more root-like level. This shift predominantly affected nuclear genes encoding plastid proteins. An organ-specific regulation was assigned to a number of genes previously known to react to a cytokinin signal, including root-specificity for the cytokinin hydroxylase gene CYP735A2 and shoot specificity for the cell cycle regulator gene CDKA;1. Numerous cytokinin-regulated genes were newly discovered or confirmed, including the meristem regulator genes SHEPHERD and CLAVATA1, auxin-related genes (IAA7, IAA13, AXR1, PIN2, PID, several genes involved in brassinosteroid (CYP710A1, CYP710A2, DIM/DWF and flavonol (MYB12, CHS, FLS1 synthesis, various transporter genes (e.g. HKT1, numerous members of the AP2/ERF transcription factor gene family, genes involved in light signalling (PhyA, COP1, SPA1, and more than 80 ribosomal genes. However, contrasting with the fundamental difference of

Exascale Co-design for Modeling Materials in Extreme Environments

Energy Technology Data Exchange (ETDEWEB)

Germann, Timothy C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-07-08

Computational materials science has provided great insight into the response of materials under extreme conditions that are difficult to probe experimentally. For example, shock-induced plasticity and phase transformation processes in single-crystal and nanocrystalline metals have been widely studied via large-scale molecular dynamics simulations, and many of these predictions are beginning to be tested at advanced 4th generation light sources such as the Advanced Photon Source (APS) and Linac Coherent Light Source (LCLS). I will describe our simulation predictions and their recent verification at LCLS, outstanding challenges in modeling the response of materials to extreme mechanical and radiation environments, and our efforts to tackle these as part of the multi-institutional, multi-disciplinary Exascale Co-design Center for Materials in Extreme Environments (ExMatEx). ExMatEx has initiated an early and deep collaboration between domain (computational materials) scientists, applied mathematicians, computer scientists, and hardware architects, in order to establish the relationships between algorithms, software stacks, and architectures needed to enable exascale-ready materials science application codes within the next decade. We anticipate that we will be able to exploit hierarchical, heterogeneous architectures to achieve more realistic large-scale simulations with adaptive physics refinement, and are using tractable application scale-bridging proxy application testbeds to assess new approaches and requirements. Such current scale-bridging strategies accumulate (or recompute) a distributed response database from fine-scale calculations, in a top-down rather than bottom-up multiscale approach.

Newly Discovered Ebola Virus Associated with Hemorrhagic Fever Outbreak in Uganda

Science.gov (United States)

Towner, Jonathan S.; Sealy, Tara K.; Khristova, Marina L.; Albariño, César G.; Conlan, Sean; Reeder, Serena A.; Quan, Phenix-Lan; Lipkin, W. Ian; Downing, Robert; Tappero, Jordan W.; Okware, Samuel; Lutwama, Julius; Bakamutumaho, Barnabas; Kayiwa, John; Comer, James A.; Rollin, Pierre E.; Ksiazek, Thomas G.; Nichol, Stuart T.

2008-01-01

Over the past 30 years, Zaire and Sudan ebolaviruses have been responsible for large hemorrhagic fever (HF) outbreaks with case fatalities ranging from 53% to 90%, while a third species, Côte d'Ivoire ebolavirus, caused a single non-fatal HF case. In November 2007, HF cases were reported in Bundibugyo District, Western Uganda. Laboratory investigation of the initial 29 suspect-case blood specimens by classic methods (antigen capture, IgM and IgG ELISA) and a recently developed random-primed pyrosequencing approach quickly identified this to be an Ebola HF outbreak associated with a newly discovered ebolavirus species (Bundibugyo ebolavirus) distantly related to the Côte d'Ivoire ebolavirus found in western Africa. Due to the sequence divergence of this new virus relative to all previously recognized ebolaviruses, these findings have important implications for design of future diagnostic assays to monitor Ebola HF disease in humans and animals, and ongoing efforts to develop effective antivirals and vaccines. PMID:19023410

Global patterns of NDVI-indicated vegetation extremes and their sensitivity to climate extremes

International Nuclear Information System (INIS)

Liu Guo; Liu Hongyan; Yin Yi

2013-01-01

Extremes in climate have significant impacts on ecosystems and are expected to increase under future climate change. Extremes in vegetation could capture such impacts and indicate the vulnerability of ecosystems, but currently have not received a global long-term assessment. In this study, a robust method has been developed to detect significant extremes (low values) in biweekly time series of global normalized difference vegetation index (NDVI) from 1982 to 2006 and thus to acquire a global pattern of vegetation extreme frequency. This pattern coincides with vegetation vulnerability patterns suggested by earlier studies using different methods over different time spans, indicating a consistent mechanism of regulation. Vegetation extremes were found to aggregate in Amazonia and in the semi-arid and semi-humid regions in low and middle latitudes, while they seldom occurred in high latitudes. Among the environmental variables studied, extreme low precipitation has the highest slope against extreme vegetation. For the eight biomes analyzed, these slopes are highest in temperate broadleaf forest and temperate grassland, suggesting a higher sensitivity in these environments. The results presented here contradict the hypothesis that vegetation in water-limited semi-arid and semi-humid regions might be adapted to drought and suggest that vegetation in these regions (especially temperate broadleaf forest and temperate grassland) is highly prone to vegetation extreme events under more severe precipitation extremes. It is also suggested here that more attention be paid to precipitation-induced vegetation changes than to temperature-induced events. (letter)

Evaluating sub-seasonal skill in probabilistic forecasts of Atmospheric Rivers and associated extreme events

Science.gov (United States)

Subramanian, A. C.; Lavers, D.; Matsueda, M.; Shukla, S.; Cayan, D. R.; Ralph, M.

2017-12-01

Atmospheric rivers (ARs) - elongated plumes of intense moisture transport - are a primary source of hydrological extremes, water resources and impactful weather along the West Coast of North America and Europe. There is strong demand in the water management, societal infrastructure and humanitarian sectors for reliable sub-seasonal forecasts, particularly of extreme events, such as floods and droughts so that actions to mitigate disastrous impacts can be taken with sufficient lead-time. Many recent studies have shown that ARs in the Pacific and the Atlantic are modulated by large-scale modes of climate variability. Leveraging the improved understanding of how these large-scale climate modes modulate the ARs in these two basins, we use the state-of-the-art multi-model forecast systems such as the North American Multi-Model Ensemble (NMME) and the Subseasonal-to-Seasonal (S2S) database to help inform and assess the probabilistic prediction of ARs and related extreme weather events over the North American and European West Coasts. We will present results from evaluating probabilistic forecasts of extreme precipitation and AR activity at the sub-seasonal scale. In particular, results from the comparison of two winters (2015-16 and 2016-17) will be shown, winters which defied canonical El Niño teleconnection patterns over North America and Europe. We further extend this study to analyze probabilistic forecast skill of AR events in these two basins and the variability in forecast skill during certain regimes of large-scale climate modes.

A New Family of Consistent and Asymptotically-Normal Estimators for the Extremal Index

Directory of Open Access Journals (Sweden)

Jose Olmo

2015-08-01

Full Text Available The extremal index (θ is the key parameter for extending extreme value theory results from i.i.d. to stationary sequences. One important property of this parameter is that its inverse determines the degree of clustering in the extremes. This article introduces a novel interpretation of the extremal index as a limiting probability characterized by two Poisson processes and a simple family of estimators derived from this new characterization. Unlike most estimators for θ in the literature, this estimator is consistent, asymptotically normal and very stable across partitions of the sample. Further, we show in an extensive simulation study that this estimator outperforms in finite samples the logs, blocks and runs estimation methods. Finally, we apply this new estimator to test for clustering of extremes in monthly time series of unemployment growth and inflation rates and conclude that runs of large unemployment rates are more prolonged than periods of high inflation.

Patterns and singular features of extreme fluctuational paths of a periodically driven system

International Nuclear Information System (INIS)

Chen, Zhen; Liu, Xianbin

2016-01-01

Large fluctuations of an overdamped periodically driven oscillating system are investigated theoretically and numerically in the limit of weak noise. Optimal paths fluctuating to certain point are given by statistical analysis using the concept of prehistory probability distribution. The validity of statistical results is verified by solutions of boundary value problem. Optimal paths are found to change topologically when terminating points lie at opposite side of a switching line. Patterns of extreme paths are plotted through a proper parameterization of Lagrangian manifold having complicated structures. Several extreme paths to the same point are obtained by multiple solutions of boundary value solutions. Actions along various extreme paths are calculated and associated analysis is performed in relation to the singular features of the patterns. - Highlights: • Both extreme and optimal paths are obtained by various methods. • Boundary value problems are solved to ensure the validity of statistical results. • Topological structure of Lagrangian manifold is considered. • Singularities of the pattern of extreme paths are studied.

Extreme seismicity and disaster risks: Hazard versus vulnerability (Invited)

Science.gov (United States)

Ismail-Zadeh, A.

2013-12-01

Although the extreme nature of earthquakes has been known for millennia due to the resultant devastation from many of them, the vulnerability of our civilization to extreme seismic events is still growing. It is partly because of the increase in the number of high-risk objects and clustering of populations and infrastructure in the areas prone to seismic hazards. Today an earthquake may affect several hundreds thousand lives and cause significant damage up to hundred billion dollars; it can trigger an ecological catastrophe if occurs in close vicinity to a nuclear power plant. Two types of extreme natural events can be distinguished: (i) large magnitude low probability events, and (ii) the events leading to disasters. Although the first-type events may affect earthquake-prone countries directly or indirectly (as tsunamis, landslides etc.), the second-type events occur mainly in economically less-developed countries where the vulnerability is high and the resilience is low. Although earthquake hazards cannot be reduced, vulnerability to extreme events can be diminished by monitoring human systems and by relevant laws preventing an increase in vulnerability. Significant new knowledge should be gained on extreme seismicity through observations, monitoring, analysis, modeling, comprehensive hazard assessment, prediction, and interpretations to assist in disaster risk analysis. The advanced disaster risk communication skill should be developed to link scientists, emergency management authorities, and the public. Natural, social, economic, and political reasons leading to disasters due to earthquakes will be discussed.

Transcriptome and network changes in climbers at extreme altitudes.

Directory of Open Access Journals (Sweden)

Fang Chen

Full Text Available Extreme altitude can induce a range of cellular and systemic responses. Although it is known that hypoxia underlies the major changes and that the physiological responses include hemodynamic changes and erythropoiesis, the molecular mechanisms and signaling pathways mediating such changes are largely unknown. To obtain a more complete picture of the transcriptional regulatory landscape and networks involved in extreme altitude response, we followed four climbers on an expedition up Mount Xixiabangma (8,012 m, and collected blood samples at four stages during the climb for mRNA and miRNA expression assays. By analyzing dynamic changes of gene networks in response to extreme altitudes, we uncovered a highly modular network with 7 modules of various functions that changed in response to extreme altitudes. The erythrocyte differentiation module is the most prominently up-regulated, reflecting increased erythrocyte differentiation from hematopoietic stem cells, probably at the expense of differentiation into other cell lineages. These changes are accompanied by coordinated down-regulation of general translation. Network topology and flow analyses also uncovered regulators known to modulate hypoxia responses and erythrocyte development, as well as unknown regulators, such as the OCT4 gene, an important regulator in stem cells and assumed to only function in stem cells. We predicted computationally and validated experimentally that increased OCT4 expression at extreme altitude can directly elevate the expression of hemoglobin genes. Our approach established a new framework for analyzing the transcriptional regulatory network from a very limited number of samples.

Early warnings of extreme winds using the ECMWF Extreme Forecast Index

OpenAIRE

Petroliagis, Thomas I.; Pinson, Pierre

2014-01-01

The European FP7 SafeWind Project aims at developing research towards a European vision of wind power forecasting, which requires advanced meteorological support concerning extreme wind events. This study is focused mainly on early warnings of extreme winds in the early medium-range. Three synoptic stations (airports) of North Germany (Bremen, Hamburg and Hannover) were considered for the construction of time series of daily maximum wind speeds. All daily wind extremes were found to be linked...

Discovering beaten paths in collaborative ontology-engineering projects using Markov chains.

Science.gov (United States)

Walk, Simon; Singer, Philipp; Strohmaier, Markus; Tudorache, Tania; Musen, Mark A; Noy, Natalya F

2014-10-01

Biomedical taxonomies, thesauri and ontologies in the form of the International Classification of Diseases as a taxonomy or the National Cancer Institute Thesaurus as an OWL-based ontology, play a critical role in acquiring, representing and processing information about human health. With increasing adoption and relevance, biomedical ontologies have also significantly increased in size. For example, the 11th revision of the International Classification of Diseases, which is currently under active development by the World Health Organization contains nearly 50,000 classes representing a vast variety of different diseases and causes of death. This evolution in terms of size was accompanied by an evolution in the way ontologies are engineered. Because no single individual has the expertise to develop such large-scale ontologies, ontology-engineering projects have evolved from small-scale efforts involving just a few domain experts to large-scale projects that require effective collaboration between dozens or even hundreds of experts, practitioners and other stakeholders. Understanding the way these different stakeholders collaborate will enable us to improve editing environments that support such collaborations. In this paper, we uncover how large ontology-engineering projects, such as the International Classification of Diseases in its 11th revision, unfold by analyzing usage logs of five different biomedical ontology-engineering projects of varying sizes and scopes using Markov chains. We discover intriguing interaction patterns (e.g., which properties users frequently change after specific given ones) that suggest that large collaborative ontology-engineering projects are governed by a few general principles that determine and drive development. From our analysis, we identify commonalities and differences between different projects that have implications for project managers, ontology editors, developers and contributors working on collaborative ontology

Discovering Beaten Paths in Collaborative Ontology-Engineering Projects using Markov Chains

Science.gov (United States)

Walk, Simon; Singer, Philipp; Strohmaier, Markus; Tudorache, Tania; Musen, Mark A.; Noy, Natalya F.

2014-01-01

Biomedical taxonomies, thesauri and ontologies in the form of the International Classification of Diseases as a taxonomy or the National Cancer Institute Thesaurus as an OWL-based ontology, play a critical role in acquiring, representing and processing information about human health. With increasing adoption and relevance, biomedical ontologies have also significantly increased in size. For example, the 11th revision of the International Classification of Diseases, which is currently under active development by the World Health Organization contains nearly 50, 000 classes representing a vast variety of different diseases and causes of death. This evolution in terms of size was accompanied by an evolution in the way ontologies are engineered. Because no single individual has the expertise to develop such large-scale ontologies, ontology-engineering projects have evolved from small-scale efforts involving just a few domain experts to large-scale projects that require effective collaboration between dozens or even hundreds of experts, practitioners and other stakeholders. Understanding the way these different stakeholders collaborate will enable us to improve editing environments that support such collaborations. In this paper, we uncover how large ontology-engineering projects, such as the International Classification of Diseases in its 11th revision, unfold by analyzing usage logs of five different biomedical ontology-engineering projects of varying sizes and scopes using Markov chains. We discover intriguing interaction patterns (e.g., which properties users frequently change after specific given ones) that suggest that large collaborative ontology-engineering projects are governed by a few general principles that determine and drive development. From our analysis, we identify commonalities and differences between different projects that have implications for project managers, ontology editors, developers and contributors working on collaborative ontology

The large sample size fallacy.

Science.gov (United States)

Lantz, Björn

2013-06-01

Significance in the statistical sense has little to do with significance in the common practical sense. Statistical significance is a necessary but not a sufficient condition for practical significance. Hence, results that are extremely statistically significant may be highly nonsignificant in practice. The degree of practical significance is generally determined by the size of the observed effect, not the p-value. The results of studies based on large samples are often characterized by extreme statistical significance despite small or even trivial effect sizes. Interpreting such results as significant in practice without further analysis is referred to as the large sample size fallacy in this article. The aim of this article is to explore the relevance of the large sample size fallacy in contemporary nursing research. Relatively few nursing articles display explicit measures of observed effect sizes or include a qualitative discussion of observed effect sizes. Statistical significance is often treated as an end in itself. Effect sizes should generally be calculated and presented along with p-values for statistically significant results, and observed effect sizes should be discussed qualitatively through direct and explicit comparisons with the effects in related literature. © 2012 Nordic College of Caring Science.

Re-discovering indigenous knowledge – Ulwazi Lwemveli for ...

African Journals Online (AJOL)

Therefore, the imperative to re-discover and re-store IK cannot be underestimated since building on this knowledge is particularly effective in helping to reach those living in rural communities. This knowledge is often the main asset they control, and certainly one with which they are more familiar. The case studies discussed ...

Evaluation of precipitation extremes over the Asian domain: observation and modelling studies

Science.gov (United States)

Kim, In-Won; Oh, Jaiho; Woo, Sumin; Kripalani, R. H.

2018-04-01

In this study, a comparison in the precipitation extremes as exhibited by the seven reference datasets is made to ascertain whether the inferences based on these datasets agree or they differ. These seven datasets, roughly grouped in three categories i.e. rain-gauge based (APHRODITE, CPC-UNI), satellite-based (TRMM, GPCP1DD) and reanalysis based (ERA-Interim, MERRA, and JRA55), having a common data period 1998-2007 are considered. Focus is to examine precipitation extremes in the summer monsoon rainfall over South Asia, East Asia and Southeast Asia. Measures of extreme precipitation include the percentile thresholds, frequency of extreme precipitation events and other quantities. Results reveal that the differences in displaying extremes among the datasets are small over South Asia and East Asia but large differences among the datasets are displayed over the Southeast Asian region including the maritime continent. Furthermore, precipitation data appear to be more consistent over East Asia among the seven datasets. Decadal trends in extreme precipitation are consistent with known results over South and East Asia. No trends in extreme precipitation events are exhibited over Southeast Asia. Outputs of the Coupled Model Intercomparison Project Phase 5 (CMIP5) simulation data are categorized as high, medium and low-resolution models. The regions displaying maximum intensity of extreme precipitation appear to be dependent on model resolution. High-resolution models simulate maximum intensity of extreme precipitation over the Indian sub-continent, medium-resolution models over northeast India and South China and the low-resolution models over Bangladesh, Myanmar and Thailand. In summary, there are differences in displaying extreme precipitation statistics among the seven datasets considered here and among the 29 CMIP5 model data outputs.

Developing Large Web Applications

CERN Document Server

Loudon, Kyle

2010-01-01

How do you create a mission-critical site that provides exceptional performance while remaining flexible, adaptable, and reliable 24/7? Written by the manager of a UI group at Yahoo!, Developing Large Web Applications offers practical steps for building rock-solid applications that remain effective even as you add features, functions, and users. You'll learn how to develop large web applications with the extreme precision required for other types of software. Avoid common coding and maintenance headaches as small websites add more pages, more code, and more programmersGet comprehensive soluti

Discovering disease-associated genes in weighted protein-protein interaction networks

Science.gov (United States)

Cui, Ying; Cai, Meng; Stanley, H. Eugene

2018-04-01

Although there have been many network-based attempts to discover disease-associated genes, most of them have not taken edge weight - which quantifies their relative strength - into consideration. We use connection weights in a protein-protein interaction (PPI) network to locate disease-related genes. We analyze the topological properties of both weighted and unweighted PPI networks and design an improved random forest classifier to distinguish disease genes from non-disease genes. We use a cross-validation test to confirm that weighted networks are better able to discover disease-associated genes than unweighted networks, which indicates that including link weight in the analysis of network properties provides a better model of complex genotype-phenotype associations.

Friction and Lubrication of Large Tilting-Pad Thrust Bearings

Directory of Open Access Journals (Sweden)

Michał Wasilczuk

2015-04-01

Full Text Available Fluid film bearings have been extensively used in the industry because of their unbeatable durability and extremely low friction coefficient, despite a very low coefficient of friction dissipation of energy being noticeable, especially in large bearings. Lubricating systems of large tilting pad thrust bearings utilized in large, vertical shaft hydrogenerators are presented in this paper. A large amount of heat is generated due to viscous shearing of the lubricant large tilting pad thrust bearings, and this requires systems for forced cooling of the lubricant. In the dominant bath lubrication systems, cooling is realized by internal coolers or external cooling systems, with the latter showing some important advantages at the cost of complexity and also, potentially, lower reliability. Substantial losses in the bearings, reaching 1 MW in extreme cases, are a good motivation for the research and development aimed at reducing them. Some possible methods and their potential efficiency, along with some effects already documented, are also described in the paper.

Genetic background of extreme violent behavior.

Science.gov (United States)

Tiihonen, J; Rautiainen, M-R; Ollila, H M; Repo-Tiihonen, E; Virkkunen, M; Palotie, A; Pietiläinen, O; Kristiansson, K; Joukamaa, M; Lauerma, H; Saarela, J; Tyni, S; Vartiainen, H; Paananen, J; Goldman, D; Paunio, T

2015-06-01

In developed countries, the majority of all violent crime is committed by a small group of antisocial recidivistic offenders, but no genes have been shown to contribute to recidivistic violent offending or severe violent behavior, such as homicide. Our results, from two independent cohorts of Finnish prisoners, revealed that a monoamine oxidase A (MAOA) low-activity genotype (contributing to low dopamine turnover rate) as well as the CDH13 gene (coding for neuronal membrane adhesion protein) are associated with extremely violent behavior (at least 10 committed homicides, attempted homicides or batteries). No substantial signal was observed for either MAOA or CDH13 among non-violent offenders, indicating that findings were specific for violent offending, and not largely attributable to substance abuse or antisocial personality disorder. These results indicate both low monoamine metabolism and neuronal membrane dysfunction as plausible factors in the etiology of extreme criminal violent behavior, and imply that at least about 5-10% of all severe violent crime in Finland is attributable to the aforementioned MAOA and CDH13 genotypes.

Extreme meteorological conditions

International Nuclear Information System (INIS)

Altinger de Schwarzkopf, M.L.

1983-01-01

Different meteorological variables which may reach significant extreme values, such as the windspeed and, in particular, its occurrence through tornadoes and hurricanes that necesarily incide and wich must be taken into account at the time of nuclear power plants' installation, are analyzed. For this kind of study, it is necessary to determine the basic phenomenum of design. Two criteria are applied to define the basic values of design for extreme meteorological variables. The first one determines the expected extreme value: it is obtained from analyzing the recurence of the phenomenum in a convened period of time, wich may be generally of 50 years. The second one determines the extreme value of low probability, taking into account the nuclear power plant's operating life -f.ex. 25 years- and considering, during said lapse, the occurrence probabilities of extreme meteorological phenomena. The values may be determined either by the deterministic method, which is based on the acknowledgement of the fundamental physical characteristics of the phenomena or by the probabilistic method, that aims to the analysis of historical statistical data. Brief comments are made on the subject in relation to the Argentine Republic area. (R.J.S.) [es

Spontaneous De-Icing Phenomena on Extremely Cold Surfaces

Science.gov (United States)

Song, Dong; Choi, Chang-Hwan

2017-11-01

Freezing of droplets on cold surfaces is universal phenomenon, while the mechanisms are still inadequately understood. Here we report spontaneous de-icing phenomena of an impacting droplet which occur on extreme cold surfaces. When a droplet impacts on cold surfaces lower than -80°, it takes more than two times longer for the droplet to freeze than the ones at -50°. Moreover, the frozen droplet below -80° breaks up into several large parts spontaneously in the end. When a droplet impacts on the extreme cold surfaces, evaporation and condensation occur immediately as the droplet approaches the substrate. A thick layer of frost forms between the droplet and substrate, decreasing the contact area of the droplet with substrate. It leads to impede the heat transfer and hence extends the freezing time significantly. On the extremely cold substrate, the droplet freezes from the center to the edge area, in contrast to a typical case freezing from the bottom to the top. This novel from-center-to-edge freezing process changes the internal tension of the frozen droplet and results in the instantaneous breakup and release eventually, which can be taken advantage of for effective deicing mechanisms.

STATISTICAL STUDY OF STRONG AND EXTREME GEOMAGNETIC DISTURBANCES AND SOLAR CYCLE CHARACTERISTICS

International Nuclear Information System (INIS)

Kilpua, E. K. J.; Olspert, N.; Grigorievskiy, A.; Käpylä, M. J.; Tanskanen, E. I.; Pelt, J.; Miyahara, H.; Kataoka, R.; Liu, Y. D.

2015-01-01

We study the relation between strong and extreme geomagnetic storms and solar cycle characteristics. The analysis uses an extensive geomagnetic index AA data set spanning over 150 yr complemented by the Kakioka magnetometer recordings. We apply Pearson correlation statistics and estimate the significance of the correlation with a bootstrapping technique. We show that the correlation between the storm occurrence and the strength of the solar cycle decreases from a clear positive correlation with increasing storm magnitude toward a negligible relationship. Hence, the quieter Sun can also launch superstorms that may lead to significant societal and economic impact. Our results show that while weaker storms occur most frequently in the declining phase, the stronger storms have the tendency to occur near solar maximum. Our analysis suggests that the most extreme solar eruptions do not have a direct connection between the solar large-scale dynamo-generated magnetic field, but are rather associated with smaller-scale dynamo and resulting turbulent magnetic fields. The phase distributions of sunspots and storms becoming increasingly in phase with increasing storm strength, on the other hand, may indicate that the extreme storms are related to the toroidal component of the solar large-scale field

STATISTICAL STUDY OF STRONG AND EXTREME GEOMAGNETIC DISTURBANCES AND SOLAR CYCLE CHARACTERISTICS

Energy Technology Data Exchange (ETDEWEB)

Kilpua, E. K. J. [Department of Physics, University Helsinki (Finland); Olspert, N.; Grigorievskiy, A.; Käpylä, M. J.; Tanskanen, E. I.; Pelt, J. [ReSoLVE Centre of Excellence, Department of Computer Science, P.O. Box 15400, FI-00076 Aalto Univeristy (Finland); Miyahara, H. [Musashino Art University, 1-736 Ogawa-cho, Kodaira-shi, Tokyo 187-8505 (Japan); Kataoka, R. [National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518 (Japan); Liu, Y. D. [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China)

2015-06-20

We study the relation between strong and extreme geomagnetic storms and solar cycle characteristics. The analysis uses an extensive geomagnetic index AA data set spanning over 150 yr complemented by the Kakioka magnetometer recordings. We apply Pearson correlation statistics and estimate the significance of the correlation with a bootstrapping technique. We show that the correlation between the storm occurrence and the strength of the solar cycle decreases from a clear positive correlation with increasing storm magnitude toward a negligible relationship. Hence, the quieter Sun can also launch superstorms that may lead to significant societal and economic impact. Our results show that while weaker storms occur most frequently in the declining phase, the stronger storms have the tendency to occur near solar maximum. Our analysis suggests that the most extreme solar eruptions do not have a direct connection between the solar large-scale dynamo-generated magnetic field, but are rather associated with smaller-scale dynamo and resulting turbulent magnetic fields. The phase distributions of sunspots and storms becoming increasingly in phase with increasing storm strength, on the other hand, may indicate that the extreme storms are related to the toroidal component of the solar large-scale field.

Complex active regions as the main source of extreme and large solar proton events

Science.gov (United States)

Ishkov, V. N.

2013-12-01

A study of solar proton sources indicated that solar flare events responsible for ≥2000 pfu proton fluxes mostly occur in complex active regions (CARs), i.e., in transition structures between active regions and activity complexes. Different classes of similar structures and their relation to solar proton events (SPEs) and evolution, depending on the origination conditions, are considered. Arguments in favor of the fact that sunspot groups with extreme dimensions are CARs are presented. An analysis of the flare activity in a CAR resulted in the detection of "physical" boundaries, which separate magnetic structures of the same polarity and are responsible for the independent development of each structure.

Rival framings: A framework for discovering how problem formulation uncertainties shape risk management trade-offs in water resources systems

Science.gov (United States)

Quinn, J. D.; Reed, P. M.; Giuliani, M.; Castelletti, A.

2017-08-01

Managing water resources systems requires coordinated operation of system infrastructure to mitigate the impacts of hydrologic extremes while balancing conflicting multisectoral demands. Traditionally, recommended management strategies are derived by optimizing system operations under a single problem framing that is assumed to accurately represent the system objectives, tacitly ignoring the myriad of effects that could arise from simplifications and mathematical assumptions made when formulating the problem. This study illustrates the benefits of a rival framings framework in which analysts instead interrogate multiple competing hypotheses of how complex water management problems should be formulated. Analyzing rival framings helps discover unintended consequences resulting from inherent biases of alternative problem formulations. We illustrate this on the monsoonal Red River basin in Vietnam by optimizing operations of the system's four largest reservoirs under several different multiobjective problem framings. In each rival framing, we specify different quantitative representations of the system's objectives related to hydropower production, agricultural water supply, and flood protection of the capital city of Hanoi. We find that some formulations result in counterintuitive behavior. In particular, policies designed to minimize expected flood damages inadvertently increase the risk of catastrophic flood events in favor of hydropower production, while min-max objectives commonly used in robust optimization provide poor representations of system tradeoffs due to their instability. This study highlights the importance of carefully formulating and evaluating alternative mathematical abstractions of stakeholder objectives describing the multisectoral water demands and risks associated with hydrologic extremes.

Large, non-saturating magnetoresistance in WTe2.

Science.gov (United States)

Ali, Mazhar N; Xiong, Jun; Flynn, Steven; Tao, Jing; Gibson, Quinn D; Schoop, Leslie M; Liang, Tian; Haldolaarachchige, Neel; Hirschberger, Max; Ong, N P; Cava, R J

2014-10-09

Magnetoresistance is the change in a material's electrical resistance in response to an applied magnetic field. Materials with large magnetoresistance have found use as magnetic sensors, in magnetic memory, and in hard drives at room temperature, and their rarity has motivated many fundamental studies in materials physics at low temperatures. Here we report the observation of an extremely large positive magnetoresistance at low temperatures in the non-magnetic layered transition-metal dichalcogenide WTe2: 452,700 per cent at 4.5 kelvins in a magnetic field of 14.7 teslas, and 13 million per cent at 0.53 kelvins in a magnetic field of 60 teslas. In contrast with other materials, there is no saturation of the magnetoresistance value even at very high applied fields. Determination of the origin and consequences of this effect, and the fabrication of thin films, nanostructures and devices based on the extremely large positive magnetoresistance of WTe2, will represent a significant new direction in the study of magnetoresistivity.

Climate Change and Hydrological Extreme Events - Risks and Perspectives for Water Management in Bavaria and Québec

Science.gov (United States)

Ludwig, R.

2017-12-01

There is as yet no confirmed knowledge whether and how climate change contributes to the magnitude and frequency of hydrological extreme events and how regional water management could adapt to the corresponding risks. The ClimEx project (2015-2019) investigates the effects of climate change on the meteorological and hydrological extreme events and their implications for water management in Bavaria and Québec. High Performance Computing is employed to enable the complex simulations in a hydro-climatological model processing chain, resulting in a unique high-resolution and transient (1950-2100) dataset of climatological and meteorological forcing and hydrological response: (1) The climate module has developed a large ensemble of high resolution data (12km) of the CRCM5 RCM for Central Europe and North-Eastern North America, downscaled from 50 members of the CanESM2 GCM. The dataset is complemented by all available data from the Euro-CORDEX project to account for the assessment of both natural climate variability and climate change. The large ensemble with several thousand model years provides the potential to catch rare extreme events and thus improves the process understanding of extreme events with return periods of 1000+ years. (2) The hydrology module comprises process-based and spatially explicit model setups (e.g. WaSiM) for all major catchments in Bavaria and Southern Québec in high temporal (3h) and spatial (500m) resolution. The simulations form the basis for in depth analysis of hydrological extreme events based on the inputs from the large climate model dataset. The specific data situation enables to establish a new method for `virtual perfect prediction', which assesses climate change impacts on flood risk and water resources management by identifying patterns in the data which reveal preferential triggers of hydrological extreme events. The presentation will highlight first results from the analysis of the large scale ClimEx model ensemble, showing the

Hydrological impacts of precipitation extremes in the Huaihe River Basin, China.

Science.gov (United States)

Yang, Mangen; Chen, Xing; Cheng, Chad Shouquan

2016-01-01

Precipitation extremes play a key role in flooding risks over the Huaihe River Basin, which is important to understand their hydrological impacts. Based on observed daily precipitation and streamflow data from 1958 to 2009, eight precipitation indices and three streamflow indices were calculated for the study of hydrological impacts of precipitation extremes. The results indicate that the wet condition intensified in the summer wet season and the drought condition was getting worse in the autumn dry season in the later years of the past 50 years. The river basin had experienced higher heavy rainfall-related flooding risks in summer and more severe drought in autumn in the later of the period. The extreme precipitation events or consecutive heavy rain day events led to the substantial increases in streamflow extremes, which are the main causes of frequent floods in the Huaihe River Basin. The large inter-annual variation of precipitation anomalies in the upper and central Huaihe River Basin are the major contributor for the regional frequent floods and droughts.

Stochastic generation of multi-site daily precipitation focusing on extreme events

Directory of Open Access Journals (Sweden)

G. Evin

2018-01-01

Full Text Available Many multi-site stochastic models have been proposed for the generation of daily precipitation, but they generally focus on the reproduction of low to high precipitation amounts at the stations concerned. This paper proposes significant extensions to the multi-site daily precipitation model introduced by Wilks, with the aim of reproducing the statistical features of extremely rare events (in terms of frequency and magnitude at different temporal and spatial scales. In particular, the first extended version integrates heavy-tailed distributions, spatial tail dependence, and temporal dependence in order to obtain a robust and appropriate representation of the most extreme precipitation fields. A second version enhances the first version using a disaggregation method. The performance of these models is compared at different temporal and spatial scales on a large region covering approximately half of Switzerland. While daily extremes are adequately reproduced at the stations by all models, including the benchmark Wilks version, extreme precipitation amounts at larger temporal scales (e.g., 3-day amounts are clearly underestimated when temporal dependence is ignored.

Extreme winter warming events more negatively impact small rather than large soil fauna: shift in community composition explained by traits not taxa.

NARCIS (Netherlands)

Bokhorst, S.F.; Phoenix, G.K.; Bjerke, J.W.; Callaghan, T.V.; Huyer-Brugman, F.A.; Berg, M.P.

2012-01-01

Extreme weather events can have negative impacts on species survival and community structure when surpassing lethal thresholds. Extreme winter warming events in the Arctic rapidly melt snow and expose ecosystems to unseasonably warm air (2-10 °C for 2-14 days), but returning to cold winter climate

Early warnings of extreme winds using the ECMWF Extreme Forecast Index

DEFF Research Database (Denmark)

Petroliagis, Thomas I.; Pinson, Pierre

2014-01-01

The European FP7 SafeWind Project aims at developing research towards a European vision of wind power forecasting, which requires advanced meteorological support concerning extreme wind events. This study is focused mainly on early warnings of extreme winds in the early medium-range. Three synoptic...... regimes. Overall, it becomes clear that the first indications of an extreme wind event might come from the ECMWF deterministic and/or probabilistic components capturing very intense weather systems (possible windstorms) in the medium term. For early warnings, all available EPS Extreme Forecast Index (EFI......) formulations were used, by linking daily maximum wind speeds to EFI values for different forecast horizons. From all possible EFI schemes deployed for issuing early warnings, the highest skill was found for the Gust Factor formulation (EFI-10FGI). Using EFI-10FGI, the corresponding 99% threshold could provide...

Rural livelihoods and household adaptation to extreme flooding in the Okavango Delta, Botswana

Science.gov (United States)

Motsholapheko, M. R.; Kgathi, D. L.; Vanderpost, C.

Adaptation to flooding is now widely adopted as an appropriate policy option since flood mitigation measures largely exceed the capability of most developing countries. In wetlands, such as the Okavango Delta, adaptation is more appropriate as these systems serve as natural flood control mechanisms. The Okavango Delta system is subject to annual variability in flooding with extreme floods resulting in adverse impacts on rural livelihoods. This study therefore seeks to improve the general understanding of rural household livelihood adaptation to extreme flooding in the Okavango Delta. Specific objectives are: (1) to assess household access to forms of capital necessary for enhanced capacity to adapt, (2) to assess the impacts of extreme flooding on household livelihoods, and (3) to identify and assess household livelihood responses to extreme flooding. The study uses the sustainable livelihood and the socio-ecological frameworks to analyse the livelihood patterns and resilience to extreme flooding. Results from a survey of 623 households in five villages, key informant interviews, focus group discussions and review of literature, indicate that access to natural capital was generally high, but low for financial, physical, human and social capital. Households mainly relied on farm-based livelihood activities, some non-farm activities, limited rural trade and public transfers. In 2004 and 2009, extreme flooding resulted in livelihood disruptions in the study areas. The main impacts included crop damage, household displacement, destruction of household property, livestock drowning and mud-trapping, the destruction of public infrastructure and disruption of services. The main household coping strategies were labour switching to other livelihood activities, temporary relocation to less affected areas, use of canoes for early harvesting or evacuation and government assistance, particularly for the most vulnerable households. Household adaptive strategies included

Erosion during extreme flood events dominates Holocene canyon evolution in northeast Iceland.

Science.gov (United States)

Baynes, Edwin R C; Attal, Mikaël; Niedermann, Samuel; Kirstein, Linda A; Dugmore, Andrew J; Naylor, Mark

2015-02-24

Extreme flood events have the potential to cause catastrophic landscape change in short periods of time (10(0) to 10(3) h). However, their impacts are rarely considered in studies of long-term landscape evolution (>10(3) y), because the mechanisms of erosion during such floods are poorly constrained. Here we use topographic analysis and cosmogenic (3)He surface exposure dating of fluvially sculpted surfaces to determine the impact of extreme flood events within the Jökulsárgljúfur canyon (northeast Iceland) and to constrain the mechanisms of bedrock erosion during these events. Surface exposure ages allow identification of three periods of intense canyon cutting about 9 ka ago, 5 ka ago, and 2 ka ago during which multiple large knickpoints retreated large distances (>2 km). During these events, a threshold flow depth was exceeded, leading to the toppling and transportation of basalt lava columns. Despite continuing and comparatively large-scale (500 m(3)/s) discharge of sediment-rich glacial meltwater, there is no evidence for a transition to an abrasion-dominated erosion regime since the last erosive event because the vertical knickpoints have not diffused over time. We provide a model for the evolution of the Jökulsárgljúfur canyon through the reconstruction of the river profile and canyon morphology at different stages over the last 9 ka and highlight the dominant role played by extreme flood events in the shaping of this landscape during the Holocene.

Extreme interplanetary rotational discontinuities at 1 AU

Science.gov (United States)

Lepping, R. P.; Wu, C.-C.

2005-11-01

This study is concerned with the identification and description of a special subset of four Wind interplanetary rotational discontinuities (from an earlier study of 134 directional discontinuities by Lepping et al. (2003)) with some "extreme" characteristics, in the sense that every case has (1) an almost planar current sheet surface, (2) a very large discontinuity angle (ω), (3) at least moderately strong normal field components (>0.8 nT), and (4) the overall set has a very broad range of transition layer thicknesses, with one being as thick as 50 RE and another at the other extreme being 1.6 RE, most being much thicker than are usually studied. Each example has a well-determined surface normal (n) according to minimum variance analysis and corroborated via time delay checking of the discontinuity with observations at IMP 8 by employing the local surface planarity. From the variance analyses, most of these cases had unusually large ratios of intermediate-to-minimum eigenvalues (λI/λmin), being on average 32 for three cases (with a fourth being much larger), indicating compact current sheet transition zones, another (the fifth) extreme property. For many years there has been a controversy as to the relative distribution of rotational (RDs) to tangential discontinuities (TDs) in the solar wind at 1 AU (and elsewhere, such as between the Sun and Earth), even to the point where some authors have suggested that RDs with large ∣Bn∣s are probably not generated or, if generated, are unstable and therefore very rare. Some of this disagreement apparently has been due to the different selection criteria used, e.g., some allowed eigenvalue ratios (λI/λmin) to be almost an order of magnitude lower than 32 in estimating n, usually introducing unacceptable error in n and therefore also in ∣Bn∣. However, we suggest that RDs may not be so rare at 1 AU, but good quality cases (where ∣Bn∣ confidently exceeds the error in ∣Bn∣) appear to be uncommon, and further

32 CFR 644.533 - Contamination discovered after return of land to owner, or sale.

Science.gov (United States)

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Contamination discovered after return of land to owner, or sale. 644.533 Section 644.533 National Defense Department of Defense (Continued) DEPARTMENT OF... Other Contamination from Proposed Excess Land and Improvements § 644.533 Contamination discovered after...

Extremely high wall-shear stress events in a turbulent boundary layer

Science.gov (United States)

Pan, Chong; Kwon, Yongseok

2018-04-01

The present work studies the fluctuating characteristics of the streamwise wall-shear stress in a DNS of a turbulent boundary layer at Re τ =1500 from a structural view. The two-dimensional field of the fluctuating friction velocity u‧ τ (x,z) is decomposed into the large- and small-scale components via a recently proposed scale separation algorithm, Quasi-bivariate Variational Mode Decomposition (QB-VMD). Both components are found to be dominated by streak-like structures, which can be regarded as the wall signature of the inner-layer streaks and the outer-layer LSMs, respectively. Extreme positive/negative wall-shear stress fluctuation events are detected in the large-scale component. The former’s occurrence frequency is nearly one order of magnitude higher than the latter; therefore, they contribute a significant portion of the long tail of the wall-shear stress distribution. Both two-point correlations and conditional averages show that these extreme positive wall-shear stress events are embedded in the large-scale positive u‧ τ streaks. They seem to be formed by near-wall ‘splatting’ process, which are related to strong finger-like sweeping (Q4) events originated from the outer-layer positive LSMs.

SDSS J013127.34–032100.1: A NEWLY DISCOVERED RADIO-LOUD QUASAR AT z = 5.18 WITH EXTREMELY HIGH LUMINOSITY

Energy Technology Data Exchange (ETDEWEB)

Yi, Wei-Min; Bai, Jin-Ming; Zhang, Ju-jia; Wang, Fang; Wang, Jian-Guo; Fan, Yu-Feng; Chang, Liang; Wang, Chuan-Jun; Lun, Bao-Li [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Wang, Feige; Wu, Xue-Bing; Yang, Jinyi; Ho, Luis C.; Zuo, Wenwen; Yang, Qian; Ai, Yanli [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Fan, Xiaohui [Steward Observatory, University of Arizona, Tucson, AZ 85721-0065 (United States); Brandt, William N. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Kim, Minjin [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Wang, Ran [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); and others

2014-11-10

Very few of the z > 5 quasars discovered to date have been radio-loud, with radio-to-optical flux ratios (radio-loudness parameters) higher than 10. Here we report the discovery of an optically luminous radio-loud quasar, SDSS J013127.34–032100.1 (J0131–0321 in short), at z = 5.18 ± 0.01 using the Lijiang 2.4 m and Magellan telescopes. J0131–0321 has a spectral energy distribution consistent with that of radio-loud quasars. With an i-band magnitude of 18.47 and a radio flux density of 33 mJy, its radio-loudness parameter is ∼100. The optical and near-infrared spectra taken by Magellan enable us to estimate its bolometric luminosity to be L {sub bol} ∼ 1.1 × 10{sup 48} erg s{sup –1}, approximately 4.5 times greater than that of the most distant quasar known to date. The black hole mass of J0131–0321 is estimated to be 2.7 × 10{sup 9} M {sub ☉}, with an uncertainty up to 0.4 dex. Detailed physical properties of this high-redshift, radio-loud, potentially super-Eddington quasar can be probed in the future with more dedicated and intensive follow-up observations using multi-wavelength facilities.

Strontium-90 Error Discovered in Subcontract Laboratory Spreadsheet. Topical Report

International Nuclear Information System (INIS)

Brown, D.D.; Nagel, A.S.

1999-07-01

West Valley Demonstration Project health physicists and environment scientists discovered a series of errors in a subcontractor's spreadsheet being used to reduce data as part of their strontium-90 analytical process

Discovering More Accurate Frequent Web Usage Patterns

OpenAIRE

Bayir, Murat Ali; Toroslu, Ismail Hakki; Cosar, Ahmet; Fidan, Guven

2008-01-01

Web usage mining is a type of web mining, which exploits data mining techniques to discover valuable information from navigation behavior of World Wide Web users. As in classical data mining, data preparation and pattern discovery are the main issues in web usage mining. The first phase of web usage mining is the data processing phase, which includes the session reconstruction operation from server logs. Session reconstruction success directly affects the quality of the frequent patterns disc...

Extreme precipitation response to climate perturbations in an atmospheric mesoscale model

NARCIS (Netherlands)

Attema, J.J.; Loriaux, J.M.; Lenderink, G.

2014-01-01

Observations of extreme (sub) hourly precipitation at midlatitudes show a large dependency on the dew point temperature often close to 14% per degree—2 times the dependency of the specific humidity on dew point temperature which is given by the Clausius–Clapeyron (CC) relation. By simulating a

Introducing the refined gravity hypothesis of extreme sexual size dimorphism

Directory of Open Access Journals (Sweden)

Corcobado Guadalupe

2010-08-01

Full Text Available Abstract Background Explanations for the evolution of female-biased, extreme Sexual Size Dimorphism (SSD, which has puzzled researchers since Darwin, are still controversial. Here we propose an extension of the Gravity Hypothesis (i.e., the GH, which postulates a climbing advantage for small males that in conjunction with the fecundity hypothesis appears to have the most general power to explain the evolution of SSD in spiders so far. In this "Bridging GH" we propose that bridging locomotion (i.e., walking upside-down under own-made silk bridges may be behind the evolution of extreme SSD. A biomechanical model shows that there is a physical constraint for large spiders to bridge. This should lead to a trade-off between other traits and dispersal in which bridging would favor smaller sizes and other selective forces (e.g. fecundity selection in females would favor larger sizes. If bridging allows faster dispersal, small males would have a selective advantage by enjoying more mating opportunities. We predicted that both large males and females would show a lower propensity to bridge, and that SSD would be negatively correlated with sexual dimorphism in bridging propensity. To test these hypotheses we experimentally induced bridging in males and females of 13 species of spiders belonging to the two clades in which bridging locomotion has evolved independently and in which most of the cases of extreme SSD in spiders are found. Results We found that 1 as the degree of SSD increased and females became larger, females tended to bridge less relative to males, and that 2 smaller males and females show a higher propensity to bridge. Conclusions Physical constraints make bridging inefficient for large spiders. Thus, in species where bridging is a very common mode of locomotion, small males, by being more efficient at bridging, will be competitively superior and enjoy more mating opportunities. This "Bridging GH" helps to solve the controversial question of

Mean versus extreme climate in the Mediterranean region and its sensitivity to future global warming conditions

Energy Technology Data Exchange (ETDEWEB)

Paeth, H.; Hense, A. [Meteorological Inst., Univ. Bonn (Germany)

2005-06-01

The Mediterranean region (MTR) has been supposed to be very sensitive to changes in land surface and atmospheric greenhouse-gas (GHG) concentrations. Particularly, an intensification of climate extremes may be associated with severe socio-economic implications. Here, we present an analysis of climate mean and extreme conditions in this subtropical area based on regional climate model experiments, simulating the present-day and possible future climate. The analysis of extreme values (EVs) is based on the assumption that the extremes of daily precipitation and near-surface temperature are well fitted by the Generalized Pareto distribution (GPD). Return values of extreme daily events are determined using the method of L-moments. Particular emphasis is laid on the evaluation of the return values with respect to the uncertainty range of the estimate as derived from a Monte Carlo sampling approach. During the most recent 25 years the MTR has become dryer in spring but more humid especially in the western part in autumn and winter. At the same time, the whole region has been subject to a substantial warming. The strongest rainfall extremes are simulated in autumn over the Mediterranean Sea around Italy. Temperature extremes are most pronounced over the land masses, especially over northern Africa. Given the large uncertainty of the EV estimate, only 1-year return values are further analysed. During recent decades, statistically significant changes in extremes are only found for temperature. Future climate conditions may come along with a decrease in mean and extreme precipitation during the cold season, whereas an intensification of the hydrological cycle is predicted in summer and autumn. Temperature is predominantly affected over the Iberian Peninsula and the eastern part of the MTR. In many grid boxes, the signals are blurred out due to the large amount of uncertainty in the EV estimate. Thus, a careful analysis is required when making inferences about the future

Characterisation of extreme winter precipitation in Mediterranean coastal sites and associated anomalous atmospheric circulation patterns

Science.gov (United States)

Toreti, A.; Xoplaki, E.; Maraun, D.; Kuglitsch, F. G.; Wanner, H.; Luterbacher, J.

2010-05-01

We present an analysis of daily extreme precipitation events for the extended winter season (October-March) at 20 Mediterranean coastal sites covering the period 1950-2006. The heavy tailed behaviour of precipitation extremes and estimated return levels, including associated uncertainties, are derived applying a procedure based on the Generalized Pareto Distribution, in combination with recently developed methods. Precipitation extremes have an important contribution to make seasonal totals (approximately 60% for all series). Three stations (one in the western Mediterranean and the others in the eastern basin) have a 5-year return level above 100 mm, while the lowest value (estimated for two Italian series) is equal to 58 mm. As for the 50-year return level, an Italian station (Genoa) has the highest value of 264 mm, while the other values range from 82 to 200 mm. Furthermore, six series (from stations located in France, Italy, Greece, and Cyprus) show a significant negative tendency in the probability of observing an extreme event. The relationship between extreme precipitation events and the large scale atmospheric circulation at the upper, mid and low troposphere is investigated by using NCEP/NCAR reanalysis data. A 2-step classification procedure identifies three significant anomaly patterns both for the western-central and eastern part of the Mediterranean basin. In the western Mediterranean, the anomalous southwesterly surface to mid-tropospheric flow is connected with enhanced moisture transport from the Atlantic. During ≥5-year return level events, the subtropical jet stream axis is aligned with the African coastline and interacts with the eddy-driven jet stream. This is connected with enhanced large scale ascending motions, instability and leads to the development of severe precipitation events. For the eastern Mediterranean extreme precipitation events, the identified anomaly patterns suggest warm air advection connected with anomalous ascent motions

Characterisation of extreme winter precipitation in Mediterranean coastal sites and associated anomalous atmospheric circulation patterns

Directory of Open Access Journals (Sweden)

A. Toreti

2010-05-01

Full Text Available We present an analysis of daily extreme precipitation events for the extended winter season (October–March at 20 Mediterranean coastal sites covering the period 1950–2006. The heavy tailed behaviour of precipitation extremes and estimated return levels, including associated uncertainties, are derived applying a procedure based on the Generalized Pareto Distribution, in combination with recently developed methods. Precipitation extremes have an important contribution to make seasonal totals (approximately 60% for all series. Three stations (one in the western Mediterranean and the others in the eastern basin have a 5-year return level above 100 mm, while the lowest value (estimated for two Italian series is equal to 58 mm. As for the 50-year return level, an Italian station (Genoa has the highest value of 264 mm, while the other values range from 82 to 200 mm. Furthermore, six series (from stations located in France, Italy, Greece, and Cyprus show a significant negative tendency in the probability of observing an extreme event. The relationship between extreme precipitation events and the large scale atmospheric circulation at the upper, mid and low troposphere is investigated by using NCEP/NCAR reanalysis data. A 2-step classification procedure identifies three significant anomaly patterns both for the western-central and eastern part of the Mediterranean basin. In the western Mediterranean, the anomalous southwesterly surface to mid-tropospheric flow is connected with enhanced moisture transport from the Atlantic. During ≥5-year return level events, the subtropical jet stream axis is aligned with the African coastline and interacts with the eddy-driven jet stream. This is connected with enhanced large scale ascending motions, instability and leads to the development of severe precipitation events. For the eastern Mediterranean extreme precipitation events, the identified anomaly patterns suggest warm air advection connected with anomalous

Intra-seasonal risk of agriculturally-relevant weather extremes in West African Sudan Savanna

Science.gov (United States)

Boansi, David; Tambo, Justice A.; Müller, Marc

2018-01-01

Using household survey data and historical daily climate data for 29 communities across Upper East Ghana and Southwest Burkina Faso, we document climatic conditions deemed major threat to farming in the West African Sudan Savanna and assess risks posed by such conditions over the period 1997-2014. Based on farmers' perception, it is found that drought, low rainfall, intense precipitation, flooding, erratic rainfall pattern, extremely high temperatures, delayed rains, and early cessation of rains are the major threats farmers face. Using first-order Markov chain model and relevant indices for monitoring weather extremes, it is discovered that climatic risk is a general inherent attribute of the rainy season in the study area. Due to recent changes in onset of rains and length of the rainy season, some farmers have either resorted to early planting of drought-hardy crops, late planting of drought-sensitive crops, or spreading of planting across the first 3 months of the season to moderate harm. Each of these planting decisions however has some risk implications. The months of May, June, and October are found to be more susceptible to relatively longer duration of dry and hot spells, while July, August, and September are found to be more susceptible to intense precipitation and flooding. To moderate harm from anticipated weather extremes, farmers need to adjust their cropping calendar, adopt appropriate crop varieties, and implement soil and water management practices. For policy makers and other stakeholders, we recommend the supply of timely and accurate weather forecasts to guide farmers in their seasonal cropping decisions and investment in/installation of low cost irrigation facilities to enhance the practice of supplemental irrigation.

Increasing occurrence of cold and warm extremes during the recent global warming slowdown.

Science.gov (United States)

Johnson, Nathaniel C; Xie, Shang-Ping; Kosaka, Yu; Li, Xichen

2018-04-30

The recent levelling of global mean temperatures after the late 1990s, the so-called global warming hiatus or slowdown, ignited a surge of scientific interest into natural global mean surface temperature variability, observed temperature biases, and climate communication, but many questions remain about how these findings relate to variations in more societally relevant temperature extremes. Here we show that both summertime warm and wintertime cold extreme occurrences increased over land during the so-called hiatus period, and that these increases occurred for distinct reasons. The increase in cold extremes is associated with an atmospheric circulation pattern resembling the warm Arctic-cold continents pattern, whereas the increase in warm extremes is tied to a pattern of sea surface temperatures resembling the Atlantic Multidecadal Oscillation. These findings indicate that large-scale factors responsible for the most societally relevant temperature variations over continents are distinct from those of global mean surface temperature.

Prediction of extreme floods in the Central Andes by means of Complex Networks

Science.gov (United States)

Boers, Niklas; Bookhagen, Bodo; Barbosa, Henrique; Marwan, Norbert; Kurths, Jürgen; Marengo, Jose

2014-05-01

Based on a non-linear synchronisation measure and complex network theory, we present a novel framework for the prediction of extreme events of spatially embedded, interrelated time series. This method is general in the sense that it can be applied to any type of spatially sampled time series with significant interrelations, ranging from climate observables to biological or stock market data. In this presentation, we apply our method to extreme rainfall in South America and show how this leads to the prediction of more than 60% (90% during El Niño conditions) of extreme rainfall events in the eastern Central Andes of Bolivia and northern Argentina, with only 1% false alarms. From paleoclimatic to decadal time scales, the Central Andes continue to be subject to pronounced changes in climatic conditions. In particular, our and past work shows that frequency as well as magnitudes of extreme rainfall events have increased significantly during past decades, calling for a better understanding of the involved climatic mechanisms. Due to their large spatial extend and occurrence at high elevations, these extreme events often lead to severe floods and landslides with disastrous socioeconomic impacts. They regularly affect tens of thousands of people and produce estimated costs of the order of several hundred million USD. Alongside with the societal value of predicting natural hazards, our study provides insights into the responsible climatic features and suggests interactions between Rossby waves in polar regions and large scale (sub-)tropical moisture transport as a driver of subseasonal variability of the South American monsoon system. Predictable extreme events result from the propagation of extreme rainfall from the region of Buenos Aires towards the Central Andes given characteristic atmospheric conditions. Our results indicate that the role of frontal systems originating from Rossby waves in polar latitudes is much more dominant for controlling extreme rainfall in

Operational experience of extreme wind penetrations

Energy Technology Data Exchange (ETDEWEB)

Estanqueiro, Ana [INETI/LNEG - National Laboratory for Energy and Geology, Lisbon (Portugal); Mateus, Carlos B. [Instituto de Meteorologia, Lisboa (Portugal); Pestana, Rui [Redes Energeticas Nacionais (REN), Lisboa (Portugal)

2010-07-01

This paper reports the operational experience from the Portuguese Power System during the 2009/2010 winter months when record wind penerations were observed: the instantaneous wind power penetration peaked at 70% of consumption during no-load periods and the wind energy accounted for more than 50% of the energy consumed for a large period. The regulation measures taken by the TSO are presented in the paper, together with the additional reserves operated for added system security. Information on the overall power system behavior under such extreme long-term wind power penetrations will also be addressed. (org.)

Observed increase in extreme daily rainfall in the French Mediterranean

Science.gov (United States)

Ribes, Aurélien; Thao, Soulivanh; Vautard, Robert; Dubuisson, Brigitte; Somot, Samuel; Colin, Jeanne; Planton, Serge; Soubeyroux, Jean-Michel

2018-04-01

We examine long-term trends in the historical record of extreme precipitation events occurring over the French Mediterranean area. Extreme events are considered in terms of their intensity, frequency, extent and precipitated volume. Changes in intensity are analysed via an original statistical approach where the annual maximum rainfall amounts observed at each measurement station are aggregated into a univariate time-series according to their dependence. The mean intensity increase is significant and estimated at + 22% (+ 7 to + 39% at the 90% confidence level) over the 1961-2015 period. Given the observed warming over the considered area, this increase is consistent with a rate of about one to three times that implied by the Clausius-Clapeyron relationship. Changes in frequency and other spatial features are investigated through a Generalised Linear Model. Changes in frequency for events exceeding high thresholds (about 200 mm in 1 day) are found to be significant, typically near a doubling of the frequency, but with large uncertainties in this change ratio. The area affected by severe events and the water volume precipitated during those events also exhibit significant trends, with an increase by a factor of about 4 for a 200 mm threshold, again with large uncertainties. All diagnoses consistently point toward an intensification of the most extreme events over the last decades. We argue that it is difficult to explain the diagnosed trends without invoking the human influence on climate.

Neuromuscular consequences of an extreme mountain ultra-marathon.

Directory of Open Access Journals (Sweden)

Guillaume Y Millet

Full Text Available We investigated the physiological consequences of one of the most extreme exercises realized by humans in race conditions: a 166-km mountain ultra-marathon (MUM with 9500 m of positive and negative elevation change. For this purpose, (i the fatigue induced by the MUM and (ii the recovery processes over two weeks were assessed. Evaluation of neuromuscular function (NMF and blood markers of muscle damage and inflammation were performed before and immediately following (n = 22, and 2, 5, 9 and 16 days after the MUM (n = 11 in experienced ultra-marathon runners. Large maximal voluntary contraction decreases occurred after MUM (-35% [95% CI: -28 to -42%] and -39% [95% CI: -32 to -46%] for KE and PF, respectively, with alteration of maximal voluntary activation, mainly for KE (-19% [95% CI: -7 to -32%]. Significant modifications in markers of muscle damage and inflammation were observed after the MUM as suggested by the large changes in creatine kinase (from 144 ± 94 to 13,633 ± 12,626 UI L(-1, myoglobin (from 32 ± 22 to 1,432 ± 1,209 µg L(-1, and C-Reactive Protein (from <2.0 to 37.7 ± 26.5 mg L(-1. Moderate to large reductions in maximal compound muscle action potential amplitude, high-frequency doublet force, and low frequency fatigue (index of excitation-contraction coupling alteration were also observed for both muscle groups. Sixteen days after MUM, NMF had returned to initial values, with most of the recovery process occurring within 9 days of the race. These findings suggest that the large alterations in NMF after an ultra-marathon race are multi-factorial, including failure of excitation-contraction coupling, which has never been described after prolonged running. It is also concluded that as early as two weeks after such an extreme running exercise, maximal force capacities have returned to baseline.

The Use of a Performance Assessment for Identifying Gifted Lebanese Students: Is DISCOVER Effective?

Science.gov (United States)

Sarouphim, Ketty M.

2009-01-01

The purpose of this study was to investigate the effectiveness of DISCOVER, a performance- based assessment in identifying gifted Lebanese students. The sample consisted of 248 students (121 boys, 127 girls) from Grades 3-5 at two private schools in Beirut, Lebanon. Students were administered DISCOVER and the Raven Standard Progressive Matrices…

Ideologies and Discourses: Extreme Narratives in Extreme Metal Music

Directory of Open Access Journals (Sweden)

Bojana Radovanović

2016-10-01

Full Text Available Historically speaking, metal music has always been about provoking a strong reaction. Depending on the characteristics of different sub-genres, one can focus on the sound, technique, visual appearance, and furthermore, the ideologies and ideas that are the foundation for each of the sub-genres. Although the majority of the metal community rejects accusations of being racially intolerant, some ideologies of extreme sub-genres (such as black metal are in fact formed around the ideas of self-conscious elitism expressed through interest in pagan mythology, racism, Nazism and fascism. There has been much interest in the Nazi era within the extreme metal scene thus influencing other sub-genres and artists. The aim of this paper is to examine various appearances of extreme narratives such as Nazism and racism in  different sub-genres of metal, bearing in mind variations dependent on geographical, political, and other factors.

Medical and psychosocial implications of adolescent extreme obesity - acceptance and effects of structured care, short: Youth with Extreme Obesity Study (YES).

Science.gov (United States)

Wabitsch, Martin; Moss, Anja; Reinehr, Thomas; Wiegand, Susanna; Kiess, Wieland; Scherag, André; Holl, Reinhard; Holle, Rolf; Hebebrand, Johannes

2013-08-29

Prevalence rates of overweight and obesity have increased in German children and adolescents in the last three decades. Adolescents with extreme obesity represent a distinct risk group. On the basis of data obtained by the German Child and Youth Survey (KiGGS) and the German district military offices we estimate that the group of extremely obese adolescents (BMI ≥ 35 kg/m2) currently encompasses approximately 200.000 adolescents aged 14 to 21 yrs. Conventional approaches focusing on weight reduction have largely proven futile for them. In addition, only a small percentage of adolescents with extreme obesity seek actively treatment for obesity while contributing disproportionately strong to health care costs. Because of somatic and psychiatric co-morbidities and social problems adolescents with extreme obesity require special attention within the medical care system. We have initiated the project "Medical and psychosocial implications of adolescents with extreme obesity--acceptance and effects of structured care, short: 'Youths with Extreme Obesity Study (YES)'", which aims at improving the medical care and social support structures for youths with extreme obesity in Germany. We focus on identification of these subjects (baseline examination) and their acceptance of diagnostic and subsequent treatment procedures. In a randomized controlled trial (RCT) we will investigate the effectiveness of a low key group intervention not focusing on weight loss but aimed at the provision of obesity related information, alleviation of social isolation, school and vocational integration and improvement of self-esteem in comparison to a control group treated in a conventional way with focus on weight loss. Interested individuals who fulfill current recommended criteria for weight loss surgery will be provided with a structured preparation and follow-up programs. All subjects will be monitored within a long-term observational study to elucidate medical and psychosocial outcomes

Extremal surface barriers

International Nuclear Information System (INIS)

Engelhardt, Netta; Wall, Aron C.

2014-01-01

We present a generic condition for Lorentzian manifolds to have a barrier that limits the reach of boundary-anchored extremal surfaces of arbitrary dimension. We show that any surface with nonpositive extrinsic curvature is a barrier, in the sense that extremal surfaces cannot be continuously deformed past it. Furthermore, the outermost barrier surface has nonnegative extrinsic curvature. Under certain conditions, we show that the existence of trapped surfaces implies a barrier, and conversely. In the context of AdS/CFT, these barriers imply that it is impossible to reconstruct the entire bulk using extremal surfaces. We comment on the implications for the firewall controversy

Climate change impact assessment of extreme precipitation on urban flash floods – case study, Aarhus, Denmark

DEFF Research Database (Denmark)

Madsen, Henrik; Sunyer Pinya, Maria Antonia; Rosbjerg, Dan

projections for estimation of changes in extreme rainfall characteristics. Climate model projections from 20 regional climate models (RCM) from the ENSEMBLES data archive were used in the analysis. Two different estimation methods were applied, using, respectively, a direct estimation of the changes...... in the extreme value statistics of the RCM data, and application of a stochastic weather generator fitted to the changes in rainfall characteristics from the RCM data. The results show a large variability in the projected changes in extreme precipitation between the different RCMs and the two estimation methods...

Screening individual hybridomas by microengraving to discover monoclonal antibodies

Science.gov (United States)

Ogunniyi, Adebola O; Story, Craig M; Papa, Eliseo; Guillen, Eduardo; Love, J Christopher

2014-01-01

The demand for monoclonal antibodies (mAbs) in biomedical research is significant, but the current methodologies used to discover them are both lengthy and costly. Consequently, the diversity of antibodies available for any particular antigen remains limited. Microengraving is a soft lithographic technique that provides a rapid and efficient alternative for discovering new mAbs. This protocol describes how to use microengraving to screen mouse hybridomas to establish new cell lines producing unique mAbs. Single cells from a polyclonal population are isolated into an array of microscale wells (~105 cells per screen). The array is then used to print a protein microarray, where each element contains the antibodies captured from individual wells. The antibodies on the microarray are screened with antigens of interest, and mapped to the corresponding cells, which are then recovered from their microwells by micromanipulation. Screening and retrieval require approximately 1–3 d (9–12 d including the steps for preparing arrays of microwells). PMID:19528952

Genomic DNA Enrichment Using Sequence Capture Microarrays: a Novel Approach to Discover Sequence Nucleotide Polymorphisms (SNP) in Brassica napus L

Science.gov (United States)

Clarke, Wayne E.; Parkin, Isobel A.; Gajardo, Humberto A.; Gerhardt, Daniel J.; Higgins, Erin; Sidebottom, Christine; Sharpe, Andrew G.; Snowdon, Rod J.; Federico, Maria L.; Iniguez-Luy, Federico L.

2013-01-01

Targeted genomic selection methodologies, or sequence capture, allow for DNA enrichment and large-scale resequencing and characterization of natural genetic variation in species with complex genomes, such as rapeseed canola (Brassica napus L., AACC, 2n=38). The main goal of this project was to combine sequence capture with next generation sequencing (NGS) to discover single nucleotide polymorphisms (SNPs) in specific areas of the B. napus genome historically associated (via quantitative trait loci –QTL– analysis) to traits of agronomical and nutritional importance. A 2.1 million feature sequence capture platform was designed to interrogate DNA sequence variation across 47 specific genomic regions, representing 51.2 Mb of the Brassica A and C genomes, in ten diverse rapeseed genotypes. All ten genotypes were sequenced using the 454 Life Sciences chemistry and to assess the effect of increased sequence depth, two genotypes were also sequenced using Illumina HiSeq chemistry. As a result, 589,367 potentially useful SNPs were identified. Analysis of sequence coverage indicated a four-fold increased representation of target regions, with 57% of the filtered SNPs falling within these regions. Sixty percent of discovered SNPs corresponded to transitions while 40% were transversions. Interestingly, fifty eight percent of the SNPs were found in genic regions while 42% were found in intergenic regions. Further, a high percentage of genic SNPs was found in exons (65% and 64% for the A and C genomes, respectively). Two different genotyping assays were used to validate the discovered SNPs. Validation rates ranged from 61.5% to 84% of tested SNPs, underpinning the effectiveness of this SNP discovery approach. Most importantly, the discovered SNPs were associated with agronomically important regions of the B. napus genome generating a novel data resource for research and breeding this crop species. PMID:24312619

Discovering the secrets of the Olifants sediments

CSIR Research Space (South Africa)

Petersen, C

2012-07-01

Full Text Available is an important component of an aquatic ecosystem in that it provides habitat, feed- ing and spawning areas for aquatic fauna such as fish and benthic Discovering the secrets of THE OLIFANTS SEDIMENTS The polluted Upper Olifants River, in Mpumalanga, has... the distribution of bed material sizes. This allows for the determination ? Top right: The Koffie- spruit, a tributary of the Upper Olifants River. Middle right: Bank erosion was evident throughout the Koffiespruit study reach. This section of river...

Metagenomic approach for discovering new pathogens in infection disease outbreaks

Directory of Open Access Journals (Sweden)

Emanuela Giombini

2011-09-01

Full Text Available Viruses represent the most abundant biological components on earth.They can be found in every environment, from deep layers of oceans to animal bodies.Although several viruses have been isolated and sequenced, in each environment there are millions of different types of viruses that have not been identified yet.The advent of nextgeneration sequencing technologies with their high throughput capabilities make possible to study in a single experiment all the community of microorganisms present in a particular sample “microbioma”.They made more feasible the application of the metagenomic approach, by which it is also possible to discover and identify new pathogens, that may pose a threat to public health.This paper summarizes the most recent applications of nextgeneration sequencing to discover new viral pathogens during the occurrence of infection disease outbreaks.

Deformation mechanisms in a coal mine roadway in extremely swelling soft rock.

Science.gov (United States)

Li, Qinghai; Shi, Weiping; Yang, Renshu

2016-01-01

The problem of roadway support in swelling soft rock was one of the challenging problems during mining. For most geological conditions, combinations of two or more supporting approaches could meet the requirements of most roadways; however, in extremely swelling soft rock, combined approaches even could not control large deformations. The purpose of this work was to probe the roadway deformation mechanisms in extremely swelling soft rock. Based on the main return air-way in a coal mine, deformation monitoring and geomechanical analysis were conducted, as well as plastic zone mechanical model was analysed. Results indicated that this soft rock was potentially very swelling. When the ground stress acted alone, the support strength needed in situ was not too large and combined supporting approaches could meet this requirement; however, when this potential released, the roadway would undergo permanent deformation. When the loose zone reached 3 m within surrounding rock, remote stress p ∞ and supporting stress P presented a linear relationship. Namely, the greater the swelling stress, the more difficult it would be in roadway supporting. So in this extremely swelling soft rock, a better way to control roadway deformation was to control the releasing of surrounding rock's swelling potential.

The Spy VI child : A newly discovered Neandertal infant

NARCIS (Netherlands)

Crevecoeur, Isabelle; Bayle, Priscilla; Rougier, Helene; Maureille, Bruno; Higham, Thomas; van der Plicht, Johannes; De Clerck, Nora; Semal, Patrick

2010-01-01

Spy cave (Jemeppe-sur-Sambre Belgium) is reputed for the two adult Neandertal individuals discovered in situ in 1886 Recent reassessment of the Spy collections has allowed direct radiocarbon dating of these individuals The sorting of all of the faunal collections has also led to the discovery of the

Regional frequency analysis of extreme rainfall in Belgium based on radar estimates

Directory of Open Access Journals (Sweden)

E. Goudenhoofdt

2017-10-01

Full Text Available In Belgium, only rain gauge time series have been used so far to study extreme rainfall at a given location. In this paper, the potential of a 12-year quantitative precipitation estimation (QPE from a single weather radar is evaluated. For the period 2005–2016, 1 and 24 h rainfall extremes from automatic rain gauges and collocated radar estimates are compared. The peak intensities are fitted to the exponential distribution using regression in Q-Q plots with a threshold rank which minimises the mean squared error. A basic radar product used as reference exhibits unrealistic high extremes and is not suitable for extreme value analysis. For 24 h rainfall extremes, which occur partly in winter, the radar-based QPE needs a bias correction. A few missing events are caused by the wind drift associated with convective cells and strong radar signal attenuation. Differences between radar and gauge rainfall values are caused by spatial and temporal sampling, gauge underestimations and radar errors. Nonetheless the fit to the QPE data is within the confidence interval of the gauge fit, which remains large due to the short study period. A regional frequency analysis for 1 h duration is performed at the locations of four gauges with 1965–2008 records using the spatially independent QPE data in a circle of 20 km. The confidence interval of the radar fit, which is small due to the sample size, contains the gauge fit for the two closest stations from the radar. In Brussels, the radar extremes are significantly higher than the gauge rainfall extremes, but similar to those observed by an automatic gauge during the same period. The extreme statistics exhibit slight variations related to topography. The radar-based extreme value analysis can be extended to other durations.

Emergency repair of upper extremity large soft tissue and vascular injuries with flow-through anterolateral thigh free flaps.

Science.gov (United States)

Zhan, Yi; Fu, Guo; Zhou, Xiang; He, Bo; Yan, Li-Wei; Zhu, Qing-Tang; Gu, Li-Qiang; Liu, Xiao-Lin; Qi, Jian

2017-12-01

Complex extremity trauma commonly involves both soft tissue and vascular injuries. Traditional two-stage surgical repair may delay rehabilitation and functional recovery, as well as increase the risk of infections. We report a single-stage reconstructive surgical method that repairs soft tissue defects and vascular injuries with flow-through free flaps to improve functional outcomes. Between March 2010 and December 2016 in our hospital, 5 patients with severe upper extremity trauma received single-stage reconstructive surgery, in which a flow-through anterolateral thigh free flap was applied to repair soft tissue defects and vascular injuries simultaneously. Cases of injured artery were reconstructed with the distal trunk of the descending branch of the lateral circumflex femoral artery. A segment of adjacent vein was used if there was a second artery injury. Patients were followed to evaluate their functional recoveries, and received computed tomography angiography examinations to assess peripheral circulation. Two patients had post-operative thumb necrosis; one required amputation, and the other was healed after debridement and abdominal pedicle flap repair. The other 3 patients had no major complications (infection, necrosis) to the recipient or donor sites after surgery. All the patients had achieved satisfactory functional recovery by the end of the follow-up period. Computed tomography angiography showed adequate circulation in the peripheral vessels. The success of these cases shows that one-step reconstructive surgery with flow-through anterolateral thigh free flaps can be a safe and effective treatment option for patients with complex upper extremity trauma with soft tissue defects and vascular injuries. Copyright © 2017. Published by Elsevier Ltd.

New twists to QCD at large-N

International Nuclear Information System (INIS)

Klinkhamer, F.R.

1984-01-01

The recently discovered reduced models of Quantum Chromodynamics in the limit of a large number (N) of colors are discussed, in particular the version that employs appropriate Z(N) twists. Some preliminary numerical data are presented, together with some new analytic results (saddle-points). This may be of some help for understanding the mechanism of confinement, which presumably is the same for all N. Also, the reduced chiral model in two dimensions is discussed

Active Luminous Blue Variables in the Large Magellanic Cloud

Energy Technology Data Exchange (ETDEWEB)

Walborn, Nolan R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Gamen, Roberto C.; Lajús, Eduardo Fernández [Instituto de Astrofísica de La Plata, CONICET–UNLP and Facultad de Ciencias Astronómicas y Geofísicas, UNLP, Paseo del Bosque s/n, La Plata (Argentina); Morrell, Nidia I. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Barbá, Rodolfo H. [Departamento de Física y Astronomía, Universidad de La Serena, Cisternas 1200 Norte, La Serena (Chile); Angeloni, Rodolfo, E-mail: walborn@stsci.edu, E-mail: rgamen@fcaglp.unlp.edu.ar, E-mail: eflajus@fcaglp.unlp.edu.ar, E-mail: nmorrell@lco.cl, E-mail: rbarba@dfuls.cl, E-mail: rangelon@gemini.edu [Gemini Observatory, Colina El Pino, Casilla 603, La Serena (Chile)

2017-07-01

We present extensive spectroscopic and photometric monitoring of two famous and currently highly active luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC), together with more limited coverage of three further, lesser known members of the class. R127 was discovered as an Ofpe/WN9 star in the 1970s but entered a classical LBV outburst in or about 1980 that is still in progress, thus enlightening us about the minimum state of such objects. R71 is currently the most luminous star in the LMC and continues to provide surprises, such as the appearance of [Ca ii] emission lines, as its spectral type becomes unprecedentedly late. Most recently, R71 has developed inverse P Cyg profiles in many metal lines. The other objects are as follows: HDE 269582, now a “second R127” that has been followed from Ofpe/WN9 to A type in its current outburst; HDE 269216, which changed from late B in 2014 to AF in 2016, its first observed outburst; and R143 in the 30 Doradus outskirts. The light curves and spectroscopic transformations are correlated in remarkable detail and their extreme reproducibility is emphasized, both for a given object and among all of them. It is now believed that some LBVs proceed directly to core collapse. One of these unstable LMC objects may thus oblige in the near future, teaching us even more about the final stages of massive stellar evolution.

Active Luminous Blue Variables in the Large Magellanic Cloud

Science.gov (United States)

Walborn, Nolan R.; Gamen, Roberto C.; Morrell, Nidia I.; Barbá, Rodolfo H.; Fernández Lajús, Eduardo; Angeloni, Rodolfo

2017-07-01

We present extensive spectroscopic and photometric monitoring of two famous and currently highly active luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC), together with more limited coverage of three further, lesser known members of the class. R127 was discovered as an Ofpe/WN9 star in the 1970s but entered a classical LBV outburst in or about 1980 that is still in progress, thus enlightening us about the minimum state of such objects. R71 is currently the most luminous star in the LMC and continues to provide surprises, such as the appearance of [Ca II] emission lines, as its spectral type becomes unprecedentedly late. Most recently, R71 has developed inverse P Cyg profiles in many metal lines. The other objects are as follows: HDE 269582, now a “second R127” that has been followed from Ofpe/WN9 to A type in its current outburst; HDE 269216, which changed from late B in 2014 to AF in 2016, its first observed outburst; and R143 in the 30 Doradus outskirts. The light curves and spectroscopic transformations are correlated in remarkable detail and their extreme reproducibility is emphasized, both for a given object and among all of them. It is now believed that some LBVs proceed directly to core collapse. One of these unstable LMC objects may thus oblige in the near future, teaching us even more about the final stages of massive stellar evolution.

Active Luminous Blue Variables in the Large Magellanic Cloud

International Nuclear Information System (INIS)

Walborn, Nolan R.; Gamen, Roberto C.; Lajús, Eduardo Fernández; Morrell, Nidia I.; Barbá, Rodolfo H.; Angeloni, Rodolfo

2017-01-01

We present extensive spectroscopic and photometric monitoring of two famous and currently highly active luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC), together with more limited coverage of three further, lesser known members of the class. R127 was discovered as an Ofpe/WN9 star in the 1970s but entered a classical LBV outburst in or about 1980 that is still in progress, thus enlightening us about the minimum state of such objects. R71 is currently the most luminous star in the LMC and continues to provide surprises, such as the appearance of [Ca ii] emission lines, as its spectral type becomes unprecedentedly late. Most recently, R71 has developed inverse P Cyg profiles in many metal lines. The other objects are as follows: HDE 269582, now a “second R127” that has been followed from Ofpe/WN9 to A type in its current outburst; HDE 269216, which changed from late B in 2014 to AF in 2016, its first observed outburst; and R143 in the 30 Doradus outskirts. The light curves and spectroscopic transformations are correlated in remarkable detail and their extreme reproducibility is emphasized, both for a given object and among all of them. It is now believed that some LBVs proceed directly to core collapse. One of these unstable LMC objects may thus oblige in the near future, teaching us even more about the final stages of massive stellar evolution.

Catheter-directed thrombolysis of below-knee deep venous thrombosis of the lower extremities

Energy Technology Data Exchange (ETDEWEB)

Roh, Byung Suk; Sohn, Young Jun; Heo, Eun A; Cho, Hyun Sun; Park, Seong Hoon; Lee, Young Hwan [Wonkwang University Hospital, Iksan (Korea, Republic of)

2008-02-15

To evaluate the technical feasibility and clinical efficacy of the use of local thrombolysis for below-knee deep vein thrombosis (DVT). From a population of 41 patients with a lower extremity DVT, the prospective clinical trial included 11 patients (7 female, 4 male, average age 61.4 years) treated with catheter-directed thrombolysis with urokinase for below-knee DVT. After removal of the proximal ilofemoral DVT, additional interventional procedures to remove the residual thrombosis and restore the venous flow from the below-knee vein were performed in cases of continuous occlusion of venous flow from the popliteal and tibial veins. Under ultrasound (US) guidance, catheter-directed thrombolysis with urokinase was performed through the ipsilateral popliteal vein. After administration of oral anticoagulation therapy, CT and venography were performed to identify patency and the presence of a recurrent thrombosis. Successful removal of the thrombus and restoration of venous flow were achieved in all of the patients (100%). Restoration of flow with a residual thrombus occurred in one case. Focal venous stenosis was discovered in four cases. The duration of urokinase infusion was 1-4 days (average 2.36 days), which was considered long. For 15.2 months, the venous lumen of all cases was preserved without a recurrent thrombosis. Catheter-directed thrombolysis is an effective procedure for recanalization of below-knee DVT in patients with a lower extremity DVT.

Catheter-directed thrombolysis of below-knee deep venous thrombosis of the lower extremities

International Nuclear Information System (INIS)

Roh, Byung Suk; Sohn, Young Jun; Heo, Eun A; Cho, Hyun Sun; Park, Seong Hoon; Lee, Young Hwan

2008-01-01

To evaluate the technical feasibility and clinical efficacy of the use of local thrombolysis for below-knee deep vein thrombosis (DVT). From a population of 41 patients with a lower extremity DVT, the prospective clinical trial included 11 patients (7 female, 4 male, average age 61.4 years) treated with catheter-directed thrombolysis with urokinase for below-knee DVT. After removal of the proximal ilofemoral DVT, additional interventional procedures to remove the residual thrombosis and restore the venous flow from the below-knee vein were performed in cases of continuous occlusion of venous flow from the popliteal and tibial veins. Under ultrasound (US) guidance, catheter-directed thrombolysis with urokinase was performed through the ipsilateral popliteal vein. After administration of oral anticoagulation therapy, CT and venography were performed to identify patency and the presence of a recurrent thrombosis. Successful removal of the thrombus and restoration of venous flow were achieved in all of the patients (100%). Restoration of flow with a residual thrombus occurred in one case. Focal venous stenosis was discovered in four cases. The duration of urokinase infusion was 1-4 days (average 2.36 days), which was considered long. For 15.2 months, the venous lumen of all cases was preserved without a recurrent thrombosis. Catheter-directed thrombolysis is an effective procedure for recanalization of below-knee DVT in patients with a lower extremity DVT

Genomic Selection Using Extreme Phenotypes and Pre-Selection of SNPs in Large Yellow Croaker (Larimichthys crocea).

Science.gov (United States)

Dong, Linsong; Xiao, Shijun; Chen, Junwei; Wan, Liang; Wang, Zhiyong

2016-10-01

Genomic selection (GS) is an effective method to improve predictive accuracies of genetic values. However, high cost in genotyping will limit the application of this technology in some species. Therefore, it is necessary to find some methods to reduce the genotyping costs in genomic selection. Large yellow croaker is one of the most commercially important marine fish species in southeast China and Eastern Asia. In this study, genotyping-by-sequencing was used to construct the libraries for the NGS sequencing and find 29,748 SNPs in the genome. Two traits, eviscerated weight (EW) and the ratio between eviscerated weight and whole body weight (REW), were chosen to study. Two strategies to reduce the costs were proposed as follows: selecting extreme phenotypes (EP) for genotyping in reference population or pre-selecting SNPs to construct low-density marker panels in candidates. Three methods of pre-selection of SNPs, i.e., pre-selecting SNPs by absolute effects (SE), by single marker analysis (SMA), and by fixed intervals of sequence number (EL), were studied. The results showed that using EP was a feasible method to save the genotyping costs in reference population. Heritability did not seem to have obvious influences on the predictive abilities estimated by EP. Using SMA was the most feasible method to save the genotyping costs in candidates. In addition, the combination of EP and SMA in genomic selection also showed good results, especially for trait of REW. We also described how to apply the new methods in genomic selection and compared the genotyping costs before and after using the new methods. Our study may not only offer a reference for aquatic genomic breeding but also offer a reference for genomic prediction in other species including livestock and plants, etc.

Carbon isotope ratios of organic matter in Bering Sea settling particles. Extremely high remineralization of organic carbon derived from diatoms

International Nuclear Information System (INIS)

Yasuda, Saki; Akagi, Tasuku; Naraoka, Hiroshi; Kitajima, Fumio; Takahashi, Kozo

2016-01-01

The carbon isotope ratios of organic carbon in settling particles collected in the highly-diatom-productive Bering Sea were determined. Wet decomposition was employed to oxidize relatively fresh organic matter. The amount of unoxidised organic carbon in the residue following wet decomposition was negligible. The δ 13 C of organic carbon in the settling particles showed a clear relationship against SiO 2 /CaCO 3 ratio of settling particles: approximately -26‰ and -19‰ at lower and higher SiO 2 /CaCO 3 ratios, respectively. The δ 13 C values were largely interpreted in terms of mixing of two major plankton sources. Both δ 13 C and compositional data can be explained consistently only by assuming that more than 98% of diatomaceous organic matter decays and that organic matter derived from carbonate-shelled plankton may remain much less remineralized. A greater amount of diatom-derived organic matter is discovered to be trapped with the increase of SiO 2 /CaCO 3 ratio of the settling particles. The ratio of organic carbon to inorganic carbon, known as the rain ratio, therefore, tends to increase proportionally with the SiO 2 /CaCO 3 ratio under an extremely diatom-productive condition. (author)

Changes in precipitation extremes projected by a 20-km mesh global atmospheric model

Directory of Open Access Journals (Sweden)

Akio Kitoh

2016-03-01

Full Text Available High-resolution modeling is necessary to project weather and climate extremes and their future changes under global warming. A global high-resolution atmospheric general circulation model with grid size about 20 km is able to reproduce climate fields as well as regional-scale phenomena such as monsoonal rainfall, tropical and extratropical cyclones, and heavy precipitation. This 20-km mesh model is applied to project future changes in weather and climate extremes at the end of the 21st century with four different spatial patterns in sea surface temperature (SST changes: one with the mean SST changes by the 28 models of the Coupled Model Intercomparison Project Phase 5 (CMIP5 under the Representative Concentration Pathways (RCP-8.5 scenario, and the other three obtained from a cluster analysis, in which tropical SST anomalies derived from the 28 CMIP5 models were grouped. Here we focus on future changes in regional precipitation and its extremes. Various precipitation indices averaged over the Twenty-two regional land domains are calculated. Heavy precipitation indices (maximum 5-day precipitation total and maximum 1-day precipitation total increase in all regional domains, even where mean precipitation decrease (Southern Africa, South Europe/Mediterranean, Central America. South Asia is the domain of the largest extreme precipitation increase. In some domains, different SST patterns result in large precipitation changes, possibly related to changes in large-scale circulations in the tropical Pacific.

Yes, Aboriginal Australians can and did discover the variability of Betelgeuse

Science.gov (United States)

Schaefer, Bradley E.

2018-04-01

Recently, a widely publicized claim has been made that the Aboriginal Australians discovered the variability of the red star Betelgeuse in the modern Orion, plus the variability of two other prominent red stars: Aldebaran and Antares. This result has excited the usual healthy skepticism, with questions about whether any untrained peoples can discover the variability and whether such a discovery is likely to be placed into lore and transmitted for long periods of time. Here, I am offering an independent evaluation, based on broad experience with naked-eye sky viewing and astro-history. I find that it is easy for inexperienced observers to detect the variability of Betelgeuse over its range in brightness from V = 0.0 to V = 1.3, for example in noticing from season-to-season that the star varies from significantly brighter than Procyon to being greatly fainter than Procyon. Further, indigenous peoples in the Southern Hemisphere inevitably kept watch on the prominent red star, so it is inevitable that the variability of Betelgeuse was discovered many times over during the last 65 millennia. The processes of placing this discovery into a cultural context (in this case, put into morality stories) and the faithful transmission for many millennia is confidently known for the Aboriginal Australians in particular. So this shows that the whole claim for a changing Betelgeuse in the Aboriginal Australian lore is both plausible and likely. Given that the discovery and transmission is easily possible, the real proof is that the Aboriginal lore gives an unambiguous statement that these stars do indeed vary in brightness, as collected by many ethnographers over a century ago from many Aboriginal groups. So I strongly conclude that the Aboriginal Australians could and did discover the variability of Betelgeuse, Aldebaran, and Antares.

Probing the extreme wind confinement of the most magnetic O star with COS spectroscopy

Science.gov (United States)

Petit, Veronique

2014-10-01

We propose to obtain phase-resolved UV spectroscopy of the recently discovered magnetic O star NGC 1624-2, which has the strongest magnetic field ever detected in a O-star, by an order of magnitude. We will use the strength and variability of the UV resonance line profiles to diagnose the density, velocity, and ionization structure of NGC 1624-2's enormous magnetosphere that results from entrapment of its stellar wind by its strong, nearly dipolar magnetic field. With this gigantic magnetosphere, NGC 1624-2 represents a new regime of extreme wind confinement that will constrain models of magnetized winds and their surface mass flux properties. A detailed understanding of such winds is necessary to study the rotational braking history of magnetic O-stars, which can shed new light on the fundamental origin of magnetism in massive, hot stars.

The dichotomous response of flood and storm extremes to rising global temperatures

Science.gov (United States)

Sharma, A.; Wasko, C.

2017-12-01

Rising temperature have resulted in increases in short-duration rainfall extremes across the world. Additionally it has been shown (doi:10.1038/ngeo2456) that storms will intensify, causing derived flood peaks to rise even more. This leads us to speculate that flood peaks will increase as a result, complying with the storyline presented in past IPCC reports. This talk, however, shows that changes in flood extremes are much more complex. Using global data on extreme flow events, the study conclusively shows that while the very extreme floods may be rising as a result of storm intensification, the more frequent flood events are decreasing in magnitude. The study argues that changes in the magnitude of floods are a function of changes in storm patterns and as well as pre-storm or antecedent conditions. It goes on to show that while changes in storms dominate for the most extreme events and over smaller, more urbanised catchments, changes in pre-storm conditions are the driving factor in modulating flood peaks in large rural catchments. The study concludes by providing recommendations on how future flood design should proceed, arguing that current practices (or using a design storm to estimate floods) are flawed and need changing.

Sexual dimorphism in epigenomicresponses of stem cells to extreme fetal growth

Science.gov (United States)

Delahaye, Fabien; Wijetunga, N. Ari; Heo, Hye J.; Tozour, Jessica N.; Zhao, Yong Mei; Greally, John M.; Einstein, Francine H.

2014-01-01

Extreme fetal growth is associated with increased susceptibility to a range of adult diseases through an unknown mechanism of cellular memory. We tested whether heritable epigenetic processes in long-lived CD34+ hematopoietic stem/progenitor cells (HSPCs) showed evidence for re-programming associated with the extremes of fetal growth. Here we show that both fetal growth restriction and over-growth are associated with global shifts towards DNA hypermethylation, targeting cis-regulatory elements in proximity to genes involved in glucose homeostasis and stem cell function. We find a sexually dimorphic response; intrauterine growth restriction (IUGR) is associated with substantially greater epigenetic dysregulation in males, whereas large for gestational age (LGA) growth predominantly affects females. The findings are consistent with extreme fetal growth interacting with variable fetal susceptibility to influence cellular aging and metabolic characteristics through epigenetic mechanisms, potentially generating biomarkers that could identify infants at higher risk for chronic disease later in life. PMID:25300954

Suction is kid's play: extremely fast suction in newborn seahorses

Science.gov (United States)

Van Wassenbergh, Sam; Roos, Gert; Genbrugge, Annelies; Leysen, Heleen; Aerts, Peter; Adriaens, Dominique; Herrel, Anthony

2009-01-01

Ongoing anatomical development typically results in a gradual maturation of the feeding movements from larval to adult fishes. Adult seahorses are known to capture prey by rotating their long-snouted head extremely quickly towards prey, followed by powerful suction. This type of suction is powered by elastic recoil and requires very precise coordination of the movements of the associated feeding structures, making it an all-or-none phenomenon. Here, we show that newborn Hippocampus reidi are able to successfully feed using an extremely rapid and powerful snout rotation combined with a high-volume suction, surpassing that observed in adult seahorses. An inverse dynamic analysis shows that an elastic recoil mechanism is also used to power head rotation in newborn H. reidi. This illustrates how extreme levels of performance in highly complex musculoskeletal systems can be present at birth given a delayed birth and rapid development of functionally important structures. The fact that the head skeleton of newborn seahorses is still largely cartilaginous may not be problematic because the hydrodynamic stress on the rotating snout appeared considerably lower than in adult syngnathids. PMID:19324657

EXTREMELY METAL-POOR GALAXIES: THE ENVIRONMENT

Energy Technology Data Exchange (ETDEWEB)

Filho, M. E. [Universidad de Las Palmas de Gran Canaria–Universidad de La Laguna, CIE Canarias: Tri-Continental Atlantic Campus, Canary Islands (Spain); Almeida, J. Sánchez; Muñoz-Tuñón, C. [Instituto Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Nuza, S. E.; Kitaura, F.; Heß, S., E-mail: mfilho@astro.up.pt [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany)

2015-04-01

We have analyzed bibliographical observational data and theoretical predictions, in order to probe the environment in which extremely metal-poor dwarf galaxies (XMPs) reside. We have assessed the H i component and its relation to the optical galaxy, the cosmic web type (voids, sheets, filaments and knots), the overdensity parameter and analyzed the nearest galaxy neighbors. The aim is to understand the role of interactions and cosmological accretion flows in the XMP observational properties, particularly the triggering and feeding of the star formation. We find that XMPs behave similarly to Blue Compact Dwarfs; they preferably populate low-density environments in the local universe: ∼60% occupy underdense regions, and ∼75% reside in voids and sheets. This is more extreme than the distribution of irregular galaxies, and in contrast to those regions preferred by elliptical galaxies (knots and filaments). We further find results consistent with previous observations; while the environment does determine the fraction of a certain galaxy type, it does not determine the overall observational properties. With the exception of five documented cases (four sources with companions and one recent merger), XMPs do not generally show signatures of major mergers and interactions; we find only one XMP with a companion galaxy within a distance of 100 kpc, and the H i gas in XMPs is typically well-behaved, demonstrating asymmetries mostly in the outskirts. We conclude that metal-poor accretion flows may be driving the XMP evolution. Such cosmological accretion could explain all the major XMP observational properties: isolation, lack of interaction/merger signatures, asymmetric optical morphology, large amounts of unsettled, metal-poor H i gas, metallicity inhomogeneities, and large specific star formation.

Multi-level programming paradigm for extreme computing

International Nuclear Information System (INIS)

Petiton, S.; Sato, M.; Emad, N.; Calvin, C.; Tsuji, M.; Dandouna, M.

2013-01-01

In order to propose a framework and programming paradigms for post peta-scale computing, on the road to exa-scale computing and beyond, we introduced new languages, associated with a hierarchical multi-level programming paradigm, allowing scientific end-users and developers to program highly hierarchical architectures designed for extreme computing. In this paper, we explain the interest of such hierarchical multi-level programming paradigm for extreme computing and its well adaptation to several large computational science applications, such as for linear algebra solvers used for reactor core physic. We describe the YML language and framework allowing describing graphs of parallel components, which may be developed using PGAS-like language such as XMP, scheduled and computed on supercomputers. Then, we propose experimentations on supercomputers (such as the 'K' and 'Hooper' ones) of the hybrid method MERAM (Multiple Explicitly Restarted Arnoldi Method) as a case study for iterative methods manipulating sparse matrices, and the block Gauss-Jordan method as a case study for direct method manipulating dense matrices. We conclude proposing evolutions for this programming paradigm. (authors)

An Extreme Protocluster of Luminous Dusty Starbursts in the Early Universe

Science.gov (United States)

Oteo, I.; Ivison, R. J.; Dunne, L.; Manilla-Robles, A.; Maddox, S.; Lewis, A. J. R.; de Zotti, G.; Bremer, M.; Clements, D. L.; Cooray, A.; Dannerbauer, H.; Eales, S.; Greenslade, J.; Omont, A.; Perez–Fournón, I.; Riechers, D.; Scott, D.; van der Werf, P.; Weiss, A.; Zhang, Z.-Y.

2018-03-01

We report the identification of an extreme protocluster of galaxies in the early universe whose core (nicknamed Distant Red Core, DRC, because of its very red color in Herschel SPIRE bands) is formed by at least 10 dusty star-forming galaxies (DSFGs), spectroscopically confirmed to lie at {z}spec}=4.002 via detection of [C I](1–0), 12CO(6–5), 12CO(4–3), 12CO(2–1), and {{{H}}}2{{O}}({2}11{--}{2}02) emission lines with ALMA and ATCA. These DSFGs are distributed over a 260 {kpc}× 310 {kpc} region and have a collective obscured star formation rate (SFR) of ∼ 6500 {M}ȯ {yr}}-1, considerably higher than those seen before in any protocluster at z≳ 4. Most of the star formation is taking place in luminous DSFGs since no Lyα emitters are detected in the protocluster core, apart from a Lyα blob located next to one of the DRC components, extending over 60 {kpc}. The total obscured SFR of the protocluster could rise to {SFR}∼ {{14,400}} {M}ȯ {yr}}-1 if all the members of an overdensity of bright DSFGs discovered around DRC in a wide-field Large APEX BOlometer CAmera 870 μm image are part of the same structure. [C I](1–0) emission reveals that DRC has a total molecular gas mass of at least {M}{{{H}}2}∼ 6.6× {10}11 {M}ȯ , and its total halo mass could be as high as ∼ 4.4× {10}13 {M}ȯ , indicating that it is the likely progenitor of a cluster at least as massive as Coma at z = 0.

Statistics of Extremes

KAUST Repository

Davison, Anthony C.

2015-04-10

Statistics of extremes concerns inference for rare events. Often the events have never yet been observed, and their probabilities must therefore be estimated by extrapolation of tail models fitted to available data. Because data concerning the event of interest may be very limited, efficient methods of inference play an important role. This article reviews this domain, emphasizing current research topics. We first sketch the classical theory of extremes for maxima and threshold exceedances of stationary series. We then review multivariate theory, distinguishing asymptotic independence and dependence models, followed by a description of models for spatial and spatiotemporal extreme events. Finally, we discuss inference and describe two applications. Animations illustrate some of the main ideas. © 2015 by Annual Reviews. All rights reserved.

The selective dynamical downscaling method for extreme-wind atlases

DEFF Research Database (Denmark)

Larsén, Xiaoli Guo; Badger, Jake; Hahmann, Andrea N.

2012-01-01

A selective dynamical downscaling method is developed to obtain extreme-wind atlases for large areas. The method is general, efficient and flexible. The method consists of three steps: (i) identifying storm episodes for a particular area, (ii) downscaling of the storms using mesoscale modelling...... and (iii) post-processing. The post-processing generalizes the winds from the mesoscale modelling to standard conditions, i.e. 10-m height over a homogeneous surface with roughness length of 5 cm. The generalized winds are then used to calculate the 50-year wind using the annual maximum method for each...... mesoscale grid point. The generalization of the mesoscale winds through the post-processing provides a framework for data validation and for applying further the mesoscale extreme winds at specific places using microscale modelling. The results are compared with measurements from two areas with different...

Moving in extreme environments: what's extreme and who decides?

Science.gov (United States)

Cotter, James David; Tipton, Michael J

2014-01-01

Humans work, rest and play in immensely varied extreme environments. The term 'extreme' typically refers to insufficiency or excess of one or more stressors, such as thermal energy or gravity. Individuals' behavioural and physiological capacity to endure and enjoy such environments varies immensely. Adverse effects of acute exposure to these environments are readily identifiable (e.g. heat stroke or bone fracture), whereas adverse effects of chronic exposure (e.g. stress fractures or osteoporosis) may be as important but much less discernable. Modern societies have increasingly sought to protect people from such stressors and, in that way, minimise their adverse effects. Regulations are thus established, and advice is provided on what is 'acceptable' exposure. Examples include work/rest cycles in the heat, hydration regimes, rates of ascent to and duration of stay at altitude and diving depth. While usually valuable and well intentioned, it is important to realise the breadth and importance of limitations associated with such guidelines. Regulations and advisories leave less room for self-determination, learning and perhaps adaptation. Regulations based on stress (e.g. work/rest cycles relative to WBGT) are more practical but less direct than those based on strain (e.g. core temperature), but even the latter can be substantively limited (e.g. by lack of criterion validation and allowance for behavioural regulation in the research on which they are based). Extreme Physiology & Medicine is publishing a series of reviews aimed at critically examining the issues involved with self- versus regulation-controlled human movement acutely and chronically in extreme environments. These papers, arising from a research symposium in 2013, are about the impact of people engaging in such environments and the effect of rules and guidelines on their safety, enjoyment, autonomy and productivity. The reviews will cover occupational heat stress, sporting heat stress, hydration, diving

[Large vessel vasculitides].

Science.gov (United States)

Morović-Vergles, Jadranka; Puksić, Silva; Gracanin, Ana Gudelj

2013-01-01

Large vessel vasculitis includes Giant cell arteritis and Takayasu arteritis. Giant cell arteritis is the most common form of vasculitis affect patients aged 50 years or over. The diagnosis should be considered in older patients who present with new onset of headache, visual disturbance, polymyalgia rheumatica and/or fever unknown cause. Glucocorticoides remain the cornerstone of therapy. Takayasu arteritis is a chronic panarteritis of the aorta ant its major branches presenting commonly in young ages. Although all large arteries can be affected, the aorta, subclavian and carotid arteries are most commonly involved. The most common symptoms included upper extremity claudication, hypertension, pain over the carotid arteries (carotidynia), dizziness and visual disturbances. Early diagnosis and treatment has improved the outcome in patients with TA.

Comparison of different statistical methods for estimation of extreme sea levels with wave set-up contribution

Science.gov (United States)

Kergadallan, Xavier; Bernardara, Pietro; Benoit, Michel; Andreewsky, Marc; Weiss, Jérôme

2013-04-01

Estimating the probability of occurrence of extreme sea levels is a central issue for the protection of the coast. Return periods of sea level with wave set-up contribution are estimated here in one site : Cherbourg in France in the English Channel. The methodology follows two steps : the first one is computation of joint probability of simultaneous wave height and still sea level, the second one is interpretation of that joint probabilities to assess a sea level for a given return period. Two different approaches were evaluated to compute joint probability of simultaneous wave height and still sea level : the first one is multivariate extreme values distributions of logistic type in which all components of the variables become large simultaneously, the second one is conditional approach for multivariate extreme values in which only one component of the variables have to be large. Two different methods were applied to estimate sea level with wave set-up contribution for a given return period : Monte-Carlo simulation in which estimation is more accurate but needs higher calculation time and classical ocean engineering design contours of type inverse-FORM in which the method is simpler and allows more complex estimation of wave setup part (wave propagation to the coast for example). We compare results from the two different approaches with the two different methods. To be able to use both Monte-Carlo simulation and design contours methods, wave setup is estimated with an simple empirical formula. We show advantages of the conditional approach compared to the multivariate extreme values approach when extreme sea-level occurs when either surge or wave height is large. We discuss the validity of the ocean engineering design contours method which is an alternative when computation of sea levels is too complex to use Monte-Carlo simulation method.

Climate Extreme Events over Northern Eurasia in Changing Climate

Science.gov (United States)

Bulygina, O.; Korshunova, N. N.; Razuvaev, V. N.; Groisman, P. Y.

2014-12-01

During the period of widespread instrumental observations in Northern Eurasia, the annual surface air temperature has increased by 1.5°C. Close to the north in the Arctic Ocean, the late summer sea ice extent has decreased by 40% providing a near-infinite source of water vapor for the dry Arctic atmosphere in the early cold season months. The contemporary sea ice changes are especially visible in the Eastern Hemisphere All these factors affect the change extreme events. Daily and sub-daily data of 940 stations to analyze variations in the space time distribution of extreme temperatures, precipitation, and wind over Russia were used. Changing in number of days with thaw over Russia was described. The total seasonal numbers of days, when daily surface air temperatures (wind, precipitation) were found to be above (below) selected thresholds, were used as indices of climate extremes. Changing in difference between maximum and minimum temperature (DTR) may produce a variety of effects on biological systems. All values falling within the intervals ranged from the lowest percentile to the 5th percentile and from the 95th percentile to the highest percentile for the time period of interest were considered as daily extremes. The number of days, N, when daily temperatures (wind, precipitation, DTR) were within the above mentioned intervals, was determined for the seasons of each year. Linear trends in the number of days were calculated for each station and for quasi-homogeneous climatic regions. Regional analysis of extreme events was carried out using quasi-homogeneous climatic regions. Maps (climatology, trends) are presented mostly for visualization purposes. Differences in regional characteristics of extreme events are accounted for over a large extent of the Russian territory and variety of its physical and geographical conditions. The number of days with maximum temperatures higher than the 95% percentile has increased in most of Russia and decreased in Siberia in

Ensemble-based evaluation of extreme water levels for the eastern Baltic Sea

Science.gov (United States)

Eelsalu, Maris; Soomere, Tarmo

2016-04-01

The risks and damages associated with coastal flooding that are naturally associated with an increase in the magnitude of extreme storm surges are one of the largest concerns of countries with extensive low-lying nearshore areas. The relevant risks are even more contrast for semi-enclosed water bodies such as the Baltic Sea where subtidal (weekly-scale) variations in the water volume of the sea substantially contribute to the water level and lead to large spreading of projections of future extreme water levels. We explore the options for using large ensembles of projections to more reliably evaluate return periods of extreme water levels. Single projections of the ensemble are constructed by means of fitting several sets of block maxima with various extreme value distributions. The ensemble is based on two simulated data sets produced in the Swedish Meteorological and Hydrological Institute. A hindcast by the Rossby Centre Ocean model is sampled with a resolution of 6 h and a similar hindcast by the circulation model NEMO with a resolution of 1 h. As the annual maxima of water levels in the Baltic Sea are not always uncorrelated, we employ maxima for calendar years and for stormy seasons. As the shape parameter of the Generalised Extreme Value distribution changes its sign and substantially varies in magnitude along the eastern coast of the Baltic Sea, the use of a single distribution for the entire coast is inappropriate. The ensemble involves projections based on the Generalised Extreme Value, Gumbel and Weibull distributions. The parameters of these distributions are evaluated using three different ways: maximum likelihood method and method of moments based on both biased and unbiased estimates. The total number of projections in the ensemble is 40. As some of the resulting estimates contain limited additional information, the members of pairs of projections that are highly correlated are assigned weights 0.6. A comparison of the ensemble-based projection of

Climate change impacts on extreme events in the United States: an uncertainty analysis

Science.gov (United States)

Extreme weather and climate events, such as heat waves, droughts and severe precipitation events, have substantial impacts on ecosystems and the economy. However, future climate simulations display large uncertainty in mean changes. As a result, the uncertainty in future changes ...

Public perceptions of climate change and extreme weather events

Science.gov (United States)

Bruine de Bruin, W.; Dessai, S.; Morgan, G.; Taylor, A.; Wong-Parodi, G.

2013-12-01

Climate experts face a serious communication challenge. Public debate about climate change continues, even though at the same time people seem to complain about extreme weather events becoming increasingly common. As compared to the abstract concept of ';climate change,' (changes in) extreme weather events are indeed easier to perceive, more vivid, and personally relevant. Public perception research in different countries has suggested that people commonly expect that climate change will lead to increases in temperature, and that unseasonably warm weather is likely to be interpreted as evidence of climate change. However, relatively little is known about whether public concerns about climate change may also be driven by changes in other types of extreme weather events, such as exceptional amounts of precipitation or flooding. We therefore examined how perceptions of and personal experiences with changes in these specific weather events are related to public concerns about climate change. In this presentation, we will discuss findings from two large public perception surveys conducted in flood-prone Pittsburgh, Pennsylvania (US) and with a national sample in the UK, where extreme flooding has recently occurred across the country. Participants completed questions about their perceptions of and experiences with specific extreme weather events, and their beliefs about climate change. We then conducted linear regressions to predict individual differences in climate-change beliefs, using perceptions of and experiences with specific extreme weather events as predictors, while controlling for demographic characteristics. The US study found that people (a) perceive flood chances to be increasing over the decades, (b) believe climate change to play a role in increases in future flood chances, and (c) would interpret future increases in flooding as evidence for climate change. The UK study found that (a) UK residents are more likely to perceive increases in ';wet' events such

Nuclear fission discovered fifty years ago

International Nuclear Information System (INIS)

Weis, M.

1988-01-01

Fifty years ago, Otto Hahn, Lise Meitner and Fritz Strassmann discovered the process of nuclear fission which, more than other scientific discoveries to date, profoundly has changed the world and continues to influence our life significantly: This discovery made the up to then incontestable physicists' view of the atom as an inseparable whole suddenly shatter to pieces. It has brought about the invaluable advantages of a peaceful utilization of nuclear energy, and at the same time put scientists in the position to build the most terrible weapon ever, threatening mankind and earth with complete destruction. All this certainly is reason enough to recall the scientists, their work and the spirit of the time. (orig.) [de

Discovering network behind infectious disease outbreak

Science.gov (United States)

Maeno, Yoshiharu

2010-11-01

Stochasticity and spatial heterogeneity are of great interest recently in studying the spread of an infectious disease. The presented method solves an inverse problem to discover the effectively decisive topology of a heterogeneous network and reveal the transmission parameters which govern the stochastic spreads over the network from a dataset on an infectious disease outbreak in the early growth phase. Populations in a combination of epidemiological compartment models and a meta-population network model are described by stochastic differential equations. Probability density functions are derived from the equations and used for the maximal likelihood estimation of the topology and parameters. The method is tested with computationally synthesized datasets and the WHO dataset on the SARS outbreak.

Learning Faster by Discovering and Exploiting Object Similarities

Directory of Open Access Journals (Sweden)

Tadej Janež

2013-03-01

Full Text Available In this paper we explore the question: “Is it possible to speed up the learning process of an autonomous agent by performing experiments in a more complex environment (i.e., an environment with a greater number of different objects?” To this end, we use a simple robotic domain, where the robot has to learn a qualitative model predicting the change in the robot's distance to an object. To quantify the environment's complexity, we defined cardinal complexity as the number of objects in the robot's world, and behavioural complexity as the number of objects' distinct behaviours. We propose Error reduction merging (ERM, a new learning method that automatically discovers similarities in the structure of the agent's environment. ERM identifies different types of objects solely from the data measured and merges the observations of objects that behave in the same or similar way in order to speed up the agent's learning. We performed a series of experiments in worlds of increasing complexity. The results in our simple domain indicate that ERM was capable of discovering structural similarities in the data which indeed made the learning faster, clearly superior to conventional learning. This observed trend occurred with various machine learning algorithms used inside the ERM method.

Discovering objects in a blood recipient information system.

Science.gov (United States)

Qiu, D; Junghans, G; Marquardt, K; Kroll, H; Mueller-Eckhardt, C; Dudeck, J

1995-01-01

Application of object-oriented (OO) methodologies has been generally considered as a solution to the problem of improving the software development process and managing the so-called software crisis. Among them, object-oriented analysis (OOA) is the most essential and is a vital prerequisite for the successful use of other OO methodologies. Though there are already a good deal of OOA methods published, the most important aspect common to all these methods: discovering objects classes truly relevant to the given problem domain, has remained a subject to be intensively researched. In this paper, using the successful development of a blood recipient information system as an example, we present our approach which is based on the conceptual framework of responsibility-driven OOA. In the discussion, we also suggest that it may be inadequate to simply attribute the software crisis to the waterfall model of the software development life-cycle. We are convinced that the real causes for the failure of some software and information systems should be sought in the methodologies used in some crucial phases of the software development process. Furthermore, a software system can also fail if object classes essential to the problem domain are not discovered, implemented and visualized, so that the real-world situation cannot be faithfully traced by it.

Development of an Evaluation Methodology for Loss of Large Area Induced from Extreme Events with Malicious Origin

International Nuclear Information System (INIS)

Kim, S.C.; Park, J.S.; Chang, D.J.; Kim, D.H.; Lee, S.W.; Lee, Y.J.; Kim, H.W.

2016-01-01

Event of loss of large area (LOLA) induced from extreme external event at multi-units nuclear installation has been emerged a new challenges in the realm of nuclear safety and regulation after Fukushima Dai-Ichi accident. The relevant information and experience on evaluation methodology and regulatory requirements are rarely available and negative to share due to the security sensitivity. Most of countries has been prepared their own regulatory requirements and methodologies to evaluate impact of LOLA at nuclear power plant. In Korea, newly amended the Nuclear Safety Acts requires to assess LOLA in terms of EDMG (Extended Damage Mitigation Guideline). Korea Institute of Nuclear Safety (KINS) has performed a pilot research project to develop the methodology and regulatory review guidance on LOLA at multi-units nuclear power plant since 2014. Through this research, we proposed a methodology to identify the strategies for preventive and mitigation of the consequences of LOLA utilizing PSA techniques or its results. The proposed methodology is comprised of 8 steps including policy consideration, threat evaluation, identification of damage path sets, SSCs capacity evaluation and identification of mitigation measures and strategies. The consequence of LOLA due to malevolent aircraft crash may significantly susceptible with analysis assumptions including type of aircraft, amount of residual fuel, and hittable angle and so on, which cannot be shared overtly. This paper introduces a evaluation methodology for LOLA using PSA technique and its results. Also we provide a case study to evaluate hittable access angle using flight simulator for two types of air crafts and to identify potential path sets leading to core damage by affected SSCs within damaged area.(author).

Ashes to ashes: Large Fraxinus germplasm collections and their fates

Science.gov (United States)

Kim C. Steiner; Paul. Lupo

2010-01-01

As the emerald ash borer (EAB) threatens the survival of our ash species, measures should be taken to preserve their genetic variability in the event that we discover a way to restore populations destroyed by the beetle. As it happens, large germplasm collections exist for our most important and widely distributed eastern species of the genus, white ash (...

Final Report for Project. Quark matter under extreme conditions

Energy Technology Data Exchange (ETDEWEB)

Incera, Vivian [Univ. of Texas, El Paso, TX (United States); Ferrer, Efrain [Univ. of Texas, El Paso, TX (United States)

2015-12-31

The results obtained in the two years of the grant have served to shine new light on several important questions about the phases of quantum chromodynamics (QCD) under extreme conditions that include quark matter at high density, as well quark-gluon plasma at high temperatures, both in the presence of strong magnetic fields. The interest in including an external magnetic field on these studies is motivated by the generation of large magnetic fields in off-central heavy-ion collisions and by their common presence in astrophysical compact objects, the two scenarios where the physics of quark matter becomes relevant. The tasks carried out in this DOE project led us, among other things, to discover the first connection between the physics of very dense quark matter and novel materials as for instance topological insulators and Weyl semimetals; they allowed us to find a physical explanation for and a solution to a standing puzzle in the apparent effect of a magnetic field on the critical temperature of the QCD chiral transition; and they led us to establish by the first time that the core of the observed two-solar-mass neutron stars could be made up of quark matter in certain inhomogeneous chiral phases in a magnetic field and that this was consistent with current astrophysical observations. A major goal established by the Nuclear Science Advisory committee in its most recent report “Reaching for the Horizon” has been “to truly understand how nuclei and strongly interacting matter in all its forms behave and can predict their behavior in new settings.” The results found in this DOE project have all contributed to address this goal, and thus they are important for advancing fundamental knowledge in the area of nuclear physics and for enhancing our understanding of the role of strong magnetic fields in the two settings where they are most relevant, neutron stars and heavy-ion collisions.

Final Report for Project. Quark matter under extreme conditions

International Nuclear Information System (INIS)

Incera, Vivian; Ferrer, Efrain

2015-01-01

The results obtained in the two years of the grant have served to shine new light on several important questions about the phases of quantum chromodynamics (QCD) under extreme conditions that include quark matter at high density, as well quark-gluon plasma at high temperatures, both in the presence of strong magnetic fields. The interest in including an external magnetic field on these studies is motivated by the generation of large magnetic fields in off-central heavy-ion collisions and by their common presence in astrophysical compact objects, the two scenarios where the physics of quark matter becomes relevant. The tasks carried out in this DOE project led us, among other things, to discover the first connection between the physics of very dense quark matter and novel materials as for instance topological insulators and Weyl semimetals; they allowed us to find a physical explanation for and a solution to a standing puzzle in the apparent effect of a magnetic field on the critical temperature of the QCD chiral transition; and they led us to establish by the first time that the core of the observed two-solar-mass neutron stars could be made up of quark matter in certain inhomogeneous chiral phases in a magnetic field and that this was consistent with current astrophysical observations. A major goal established by the Nuclear Science Advisory committee in its most recent report 'Reaching for the Horizon' has been 'to truly understand how nuclei and strongly interacting matter in all its forms behave and can predict their behavior in new settings.' The results found in this DOE project have all contributed to address this goal, and thus they are important for advancing fundamental knowledge in the area of nuclear physics and for enhancing our understanding of the role of strong magnetic fields in the two settings where they are most relevant, neutron stars and heavy-ion collisions.

Evaluation of trends in high temperature extremes in north-western Europe in regional climate models

International Nuclear Information System (INIS)

Min, E; Hazeleger, W; Van Oldenborgh, G J; Sterl, A

2013-01-01

Projections of future changes in weather extremes on the regional and local scale depend on a realistic representation of trends in extremes in regional climate models (RCMs). We have tested this assumption for moderate high temperature extremes (the annual maximum of the daily maximum 2 m temperature, T ann.max ). Linear trends in T ann.max from historical runs of 14 RCMs driven by atmospheric reanalysis data are compared with trends in gridded station data. The ensemble of RCMs significantly underestimates the observed trends over most of the north-western European land surface. Individual models do not fare much better, with even the best performing models underestimating observed trends over large areas. We argue that the inability of RCMs to reproduce observed trends is probably not due to errors in large-scale circulation. There is also no significant correlation between the RCM T ann.max trends and trends in radiation or Bowen ratio. We conclude that care should be taken when using RCM data for adaptation decisions. (letter)

ISLSCP II IGBP DISCover and SiB Land Cover, 1992-1993

Data.gov (United States)

National Aeronautics and Space Administration — This data set describes the geographic distributions of 17 classes of land cover based on the International Geosphere-Biosphere DISCover land cover legend (Loveland...

Evolution caused by extreme events.

Science.gov (United States)

Grant, Peter R; Grant, B Rosemary; Huey, Raymond B; Johnson, Marc T J; Knoll, Andrew H; Schmitt, Johanna

2017-06-19

Extreme events can be a major driver of evolutionary change over geological and contemporary timescales. Outstanding examples are evolutionary diversification following mass extinctions caused by extreme volcanism or asteroid impact. The evolution of organisms in contemporary time is typically viewed as a gradual and incremental process that results from genetic change, environmental perturbation or both. However, contemporary environments occasionally experience strong perturbations such as heat waves, floods, hurricanes, droughts and pest outbreaks. These extreme events set up strong selection pressures on organisms, and are small-scale analogues of the dramatic changes documented in the fossil record. Because extreme events are rare, almost by definition, they are difficult to study. So far most attention has been given to their ecological rather than to their evolutionary consequences. We review several case studies of contemporary evolution in response to two types of extreme environmental perturbations, episodic (pulse) or prolonged (press). Evolution is most likely to occur when extreme events alter community composition. We encourage investigators to be prepared for evolutionary change in response to rare events during long-term field studies.This article is part of the themed issue 'Behavioural, ecological and evolutionary responses to extreme climatic events'. © 2017 The Author(s).

Experiments on extreme states of matter towards HIF at FAIR

International Nuclear Information System (INIS)

Sharkov, B.; Varentsov, D.

2013-01-01

The Facility for Antiproton and Ion Research in Europe (FAIR) will provide worldwide unique accelerator and experimental facilities allowing for a large variety of unprecedented frontier research in extreme state of matter physics and applied science. Indeed, it is the largest basic research project on the roadmap of the European Strategy Forum of Research Infrastructures (ESFRI), and it is cornerstone of the European Research Area. FAIR offers to scientists from the whole world an abundance of outstanding research opportunities, broader in scope than any other contemporary large-scale facility worldwide. More than 2500 scientists are involved in setting up and exploiting the FAIR facility. They will push the frontiers of our knowledge in plasma, nuclear, atomic, hadron and applied physics far ahead, with important implications also for other fields in science such as cosmology, astro and particle physics, and technology. It includes 14 initial experiments, which form the four scientific pillars of FAIR. The main thrust of intense heavy ion and laser beam-matter interaction research focuses on the structure and evolution of extreme state of matter on both a microscopic and on a cosmic scale. (authors)

Temporal and spatial scaling impacts on extreme precipitation

Science.gov (United States)

Eggert, B.; Berg, P.; Haerter, J. O.; Jacob, D.; Moseley, C.

2015-01-01

Both in the current climate and in the light of climate change, understanding of the causes and risk of precipitation extremes is essential for protection of human life and adequate design of infrastructure. Precipitation extreme events depend qualitatively on the temporal and spatial scales at which they are measured, in part due to the distinct types of rain formation processes that dominate extremes at different scales. To capture these differences, we first filter large datasets of high-resolution radar measurements over Germany (5 min temporally and 1 km spatially) using synoptic cloud observations, to distinguish convective and stratiform rain events. In a second step, for each precipitation type, the observed data are aggregated over a sequence of time intervals and spatial areas. The resulting matrix allows a detailed investigation of the resolutions at which convective or stratiform events are expected to contribute most to the extremes. We analyze where the statistics of the two types differ and discuss at which resolutions transitions occur between dominance of either of the two precipitation types. We characterize the scales at which the convective or stratiform events will dominate the statistics. For both types, we further develop a mapping between pairs of spatially and temporally aggregated statistics. The resulting curve is relevant when deciding on data resolutions where statistical information in space and time is balanced. Our study may hence also serve as a practical guide for modelers, and for planning the space-time layout of measurement campaigns. We also describe a mapping between different pairs of resolutions, possibly relevant when working with mismatched model and observational resolutions, such as in statistical bias correction.

Climate extremes drive changes in functional community structure.

Science.gov (United States)

Boucek, Ross E; Rehage, Jennifer S

2014-06-01

The response of communities to climate extremes can be quite variable. Much of this variation has been attributed to differences in community-specific functional trait diversity, as well as community composition. Yet, few if any studies have explicitly tested the response of the functional trait structure of communities following climate extremes (CEs). Recently in South Florida, two independent, but sequential potential CEs took place, a 2010 cold front, followed by a 2011 drought, both of which had profound impacts on a subtropical estuarine fish community. These CEs provided an opportunity to test whether the structure of South Florida fish communities following each extreme was a result of species-specific differences in functional traits. From historical temperature (1927-2012) and freshwater inflows records into the estuary (1955-2012), we determined that the cold front was a statistically extreme disturbance, while the drought was not, but rather a decadal rare disturbance. The two disturbances predictably affected different parts of functional community structure and thus different component species. The cold front virtually eliminated tropical species, including large-bodied snook, mojarra species, nonnative cichlids, and striped mullet, while having little affect on temperate fishes. Likewise, the drought severely impacted freshwater fishes including Florida gar, bowfin, and two centrarchids, with little effect on euryhaline species. Our findings illustrate the ability of this approach to predict and detect both the filtering effects of different types of disturbances and the implications of the resulting changes in community structure. Further, we highlight the value of this approach to developing predictive frameworks for better understanding community responses to global change. © 2014 John Wiley & Sons Ltd.

Discovering and explaining work-family strategies of parents in Luxembourg

NARCIS (Netherlands)

Zhelyazkova, Nevena

2014-01-01

The presented analysis discovers and explains typical patterns of work-family reconciliation for parents who had a child in the same period (2003) and in the same country (Luxembourg), thus facing the same macroeconomic and institutional conditions. Work-family trajectories are reconstructed as

Advanced Cell Classifier: User-Friendly Machine-Learning-Based Software for Discovering Phenotypes in High-Content Imaging Data.

Science.gov (United States)

Piccinini, Filippo; Balassa, Tamas; Szkalisity, Abel; Molnar, Csaba; Paavolainen, Lassi; Kujala, Kaisa; Buzas, Krisztina; Sarazova, Marie; Pietiainen, Vilja; Kutay, Ulrike; Smith, Kevin; Horvath, Peter

2017-06-28

High-content, imaging-based screens now routinely generate data on a scale that precludes manual verification and interrogation. Software applying machine learning has become an essential tool to automate analysis, but these methods require annotated examples to learn from. Efficiently exploring large datasets to find relevant examples remains a challenging bottleneck. Here, we present Advanced Cell Classifier (ACC), a graphical software package for phenotypic analysis that addresses these difficulties. ACC applies machine-learning and image-analysis methods to high-content data generated by large-scale, cell-based experiments. It features methods to mine microscopic image data, discover new phenotypes, and improve recognition performance. We demonstrate that these features substantially expedite the training process, successfully uncover rare phenotypes, and improve the accuracy of the analysis. ACC is extensively documented, designed to be user-friendly for researchers without machine-learning expertise, and distributed as a free open-source tool at www.cellclassifier.org. Copyright © 2017 Elsevier Inc. All rights reserved.

Exploring societal solidarity in the context of extreme prematurity.

Science.gov (United States)

Hendriks, Manya J; Bucher, Hans Ulrich; Klein, Sabine D; Streuli, Jürg C; Baumann-Hölzle, Ruth; Fauchère, Jean-Claude

2017-03-21

Extreme prematurity can result in long-term disabilities. Its impact on society is often not taken into account and deemed controversial. Our study examined attitudes of the Swiss population regarding extreme prematurity and people's perspectives regarding the question of solidarity with disabled people. We conducted a nationwide representative anonymous telephone survey with 1210 Swiss residents aged 18 years or older. We asked how people estimate their own personal solidarity, the solidarity of their social environment and the solidarity across the country with disabled persons. Spearman's correlation calculations were used to assess if a correlation exists between solidarity and setting financial limits to intensive care and between solidarity and withholding neonatal intensive care. According to 36.0% of the respondents intensive medical care should not be withheld from extremely preterm infants, even if their chances for an acceptable quality of life were poor. For 28.8%, intensive care should be withheld from these infants, and 26.9% held an intermediate position depending on the situation. A total of 31.5% were against setting a financial limit to treatment of extremely preterm newborns with an uncertain future quality of life, 34.2% were in favour and 26.9% were deliberating. A majority (88.8%) considered their solidarity toward disabled people as substantial; the solidarity of their personal environment and of the society at large was estimated as high by 79.1% and 48.6%, respectively. The Swiss population expressed a high level of solidarity which may alleviate some pressure on parents and health care providers in the decision-making process in neonatal intensive care units. In addition, there was no relationship between solidarity and people's willingness to pay for the care or withholding treatment of extremely preterm babies.

Domain Decomposition for Computing Extremely Low Frequency Induced Current in the Human Body

OpenAIRE

Perrussel , Ronan; Voyer , Damien; Nicolas , Laurent; Scorretti , Riccardo; Burais , Noël

2011-01-01

International audience; Computation of electromagnetic fields in high resolution computational phantoms requires solving large linear systems. We present an application of Schwarz preconditioners with Krylov subspace methods for computing extremely low frequency induced fields in a phantom issued from the Visible Human.

Glowing Hot Transiting Exoplanet Discovered

Science.gov (United States)

2003-04-01

VLT Spectra Indicate Shortest-Known-Period Planet Orbiting OGLE-TR-3 Summary More than 100 exoplanets in orbit around stars other than the Sun have been found so far. But while their orbital periods and distances from their central stars are well known, their true masses cannot be determined with certainty, only lower limits. This fundamental limitation is inherent in the common observational method to discover exoplanets - the measurements of small and regular changes in the central star's velocity, caused by the planet's gravitational pull as it orbits the star. However, in two cases so far, it has been found that the exoplanet's orbit happens to be positioned in such a way that the planet moves in front of the stellar disk, as seen from the Earth. This "transit" event causes a small and temporary dip in the star's brightness, as the planet covers a small part of its surface, which can be observed. The additional knowledge of the spatial orientation of the planetary orbit then permits a direct determination of the planet's true mass. Now, a group of German astronomers [1] have found a third star in which a planet, somewhat larger than Jupiter, but only half as massive, moves in front of the central star every 28.5 hours . The crucial observation of this solar-type star, designated OGLE-TR-3 [2] was made with the high-dispersion UVES spectrograph on the Very Large Telescope (VLT) at the ESO Paranal Observatory (Chile). It is the exoplanet with the shortest period found so far and it is very close to the star, only 3.5 million km away. The hemisphere that faces the star must be extremely hot, about 2000 °C and the planet is obviously losing its atmosphere at high rate . PR Photo 10a/03 : The star OGLE-TR-3 . PR Photo 10b/03 : VLT UVES spectrum of OGLE-TR-3. PR Photo 10c/03 : Relation between stellar brightness and velocity (diagram). PR Photo 10d/03 : Observed velocity variation of OGLE-TR-3. PR Photo 10e/03 : Observed brightness variation of OGLE-TR-3. The search

Assessment of extreme value distributions for maximum temperature in the Mediterranean area

Science.gov (United States)

Beck, Alexander; Hertig, Elke; Jacobeit, Jucundus

2015-04-01

Extreme maximum temperatures highly affect the natural as well as the societal environment Heat stress has great effects on flora, fauna and humans and culminates in heat related morbidity and mortality. Agriculture and different industries are severely affected by extreme air temperatures. Even more under climate change conditions, it is necessary to detect potential hazards which arise from changes in the distributional parameters of extreme values, and this is especially relevant for the Mediterranean region which is characterized as a climate change hot spot. Therefore statistical approaches are developed to estimate these parameters with a focus on non-stationarities emerging in the relationship between regional climate variables and their large-scale predictors like sea level pressure, geopotential heights, atmospheric temperatures and relative humidity. Gridded maximum temperature data from the daily E-OBS dataset (Haylock et al., 2008) with a spatial resolution of 0.25° x 0.25° from January 1950 until December 2012 are the predictands for the present analyses. A s-mode principal component analysis (PCA) has been performed in order to reduce data dimension and to retain different regions of similar maximum temperature variability. The grid box with the highest PC-loading represents the corresponding principal component. A central part of the analyses is the model development for temperature extremes under the use of extreme value statistics. A combined model is derived consisting of a Generalized Pareto Distribution (GPD) model and a quantile regression (QR) model which determines the GPD location parameters. The QR model as well as the scale parameters of the GPD model are conditioned by various large-scale predictor variables. In order to account for potential non-stationarities in the predictors-temperature relationships, a special calibration and validation scheme is applied, respectively. Haylock, M. R., N. Hofstra, A. M. G. Klein Tank, E. J. Klok, P

Newly Discovered Items of the Zoomorphic Style from the Left Bank of the Lower Dniester

Directory of Open Access Journals (Sweden)

Sinika Vitalij S.

2017-09-01

Full Text Available The article presents an overview of items corresponding to the Scythian zoomorphic style discovered at barbaric and ancient sites of the Northwestern Black Sea Region, and a publication of two new findings. They were discovered on the left bank of the Lower Dniester. The first item discovered at Parkany-II settlement is a fragment of a bronze horse plaque (its lower part crafted in the shape of a "rooster"-hippocampus. The other artifact discovered near Tokmazeya village also represents a horse plaque with an image of a cat predator's head. Presently, there are no counterparts of the images on these findings in the Northwestern Black Sea Region, which is the westmost periphery of the Scythian steppe culture. These fragments of horse apparel broaden our knowledge of the Scythian "bestiary" in the region. Besides, apart from the other items of material culture, the published findings confirm the presence of Scythian population at settlement sites, which contradicts the generally accepted opinion on the exclusively nomadic cattle breeding lifestyle of the Scythians in 5th –4th centuries B.C.

Prevention through policy: Urban macroplastic leakages to the marine environment during extreme rainfall events.

Science.gov (United States)

Axelsson, Charles; van Sebille, Erik

2017-11-15

The leakage of large plastic litter (macroplastics) into the ocean is a major environmental problem. A significant fraction of this leakage originates from coastal cities, particularly during extreme rainfall events. As coastal cities continue to grow, finding ways to reduce this macroplastic leakage is extremely pertinent. Here, we explore why and how coastal cities can reduce macroplastic leakages during extreme rainfall events. Using nine global cities as a basis, we establish that while cities actively create policies that reduce plastic leakages, more needs to be done. Nonetheless, these policies are economically, socially and environmentally cobeneficial to the city environment. While the lack of political engagement and economic concerns limit these policies, lacking social motivation and engagement is the largest limitation towards implementing policy. We recommend cities to incentivize citizen and municipal engagement with responsible usage of plastics, cleaning the environment and preparing for future extreme rainfall events. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

US NSF: scientists discover planetary system similar to our own

CERN Multimedia

2003-01-01

An international team of scientists has discovered a planet and star that may share the same relationship as Jupiter and our Sun, the closest comparison that researchers have found since they began their search for extra-solar planets nearly a decade ago (1 page).

Likelihood estimators for multivariate extremes

KAUST Repository

Huser, Raphaë l; Davison, Anthony C.; Genton, Marc G.

2015-01-01

The main approach to inference for multivariate extremes consists in approximating the joint upper tail of the observations by a parametric family arising in the limit for extreme events. The latter may be expressed in terms of componentwise maxima, high threshold exceedances or point processes, yielding different but related asymptotic characterizations and estimators. The present paper clarifies the connections between the main likelihood estimators, and assesses their practical performance. We investigate their ability to estimate the extremal dependence structure and to predict future extremes, using exact calculations and simulation, in the case of the logistic model.

Likelihood estimators for multivariate extremes

KAUST Repository

Huser, Raphaël

2015-11-17

The main approach to inference for multivariate extremes consists in approximating the joint upper tail of the observations by a parametric family arising in the limit for extreme events. The latter may be expressed in terms of componentwise maxima, high threshold exceedances or point processes, yielding different but related asymptotic characterizations and estimators. The present paper clarifies the connections between the main likelihood estimators, and assesses their practical performance. We investigate their ability to estimate the extremal dependence structure and to predict future extremes, using exact calculations and simulation, in the case of the logistic model.

The Influence of the Madden-Julian Oscillation (mjo) on Extreme Rainfall Over the Central and Southern Peruvian Andes

Science.gov (United States)

Heidinger, H.; Jones, C.; Carvalho, L. V.

2015-12-01

Extreme rainfall is important for the Andean region because of the large contribution of these events to the seasonal totals and consequent impacts on water resources for agriculture, water consumption, industry and hydropower generation, as well as the occurrence of floods and landslides. Over Central and Southern Peruvian Andes (CSPA), rainfall exceeding the 90th percentile contributed between 44 to 100% to the total Nov-Mar 1979-2010 rainfall. Additionally, precipitation from a large majority of stations in the CSPA exhibits statistically significant spectral peaks on intraseasonal time-scales (20 to 70 days). The Madden-Julian Oscillation (MJO) is the most important intraseasonal mode of atmospheric circulation and moist convection in the tropics and the occurrence of extreme weather events worldwide. Mechanisms explaining the relationships between the MJO and precipitation in the Peruvian Andes have not been properly described yet. The present study examines the relationships between the activity and phases of the MJO and the occurrence of extreme rainfall over the CSPA. We found that the frequency of extreme rainfall events increase in the CSPA when the MJO is active. MJO phases 5, 6 and 7 contribute to the overall occurrence of extreme rainfall events over the CSPA. However, how the MJO phases modulate extreme rainfall depends on the location of the stations. For instance, extreme precipitation (above the 90th percentile) in stations in the Amazon basin are slightly more sensitive to phases 2, 3 and 4; the frequency of extremes in stations in the Pacific basin increases in phases 5, 6 and 7 whereas phase 2, 3 and 7 modulates extreme precipitation in stations in the Titicaca basin. Greater variability among stations is observed when using the 95th and 99th percentiles to identify extremes. Among the main mechanisms that explain the increase in extreme rainfall events in the Peruvian Andes is the intensification of the easterly moisture flux anomalies, which

Hydroclimatic Extremes and Cholera Dynamics in the 21st Century

Science.gov (United States)

Akanda, A. S.; Jutla, A. S.; Islam, S.

2012-12-01

Cholera, an acute water-borne diarrheal illness, has reemerged as a significant health threat across much of the developing world. Despite major advances in the ecological and the microbiological understanding of the causative agent, V. cholerae, the role of the underlying climatic and environmental processes in propagating transmission is not adequately understood. Recent findings suggest a more prominent role of hydroclimatic extremes - droughts and floods - on the unique dual cholera peaks in the Bengal Delta region of South Asia, the native homeland of cholera. Increasing water scarcity and abundance, and coastal sea-level rise, influenced by changing climate patterns and large-scale climatic phenomena, is likely to adversely impact cholera transmission in South Asia. We focus on understanding how associated changes in macro-scale conditions in this region will impact micro-scale processes related to cholera in coming decades. We use the PRECIS Regional Climate Model over the Ganges-Brahmaputra-Meghna (GBM) basin region to simulate detailed high resolution projections of climate patterns for the 21st century. Precipitation outputs are analyzed for the 1980-2040 period to identify the trends and changes in hydroclimatic extremes and potential impacts on cholera dynamics over the next three decades (2010-2040), in relation to the cholera surveillance operations over the past three decades (1980-2010). We find that an increased number of extreme precipitation events with prolonged dry periods in the Ganges basin region will likely adversely affect dry season cholera outbreaks. Increased monsoon precipitation volumes in the Brahmaputra basin catchments are likely to cause record floods and subsequently trigger large epidemics in downstream areas. Our results provide new insight by identifying the changes in the two distinctly different, pre and post monsoon, cholera transmission mechanisms related to large-scale climatic controls that prevail in the region. A

Classifying Returns as Extreme

DEFF Research Database (Denmark)

Christiansen, Charlotte

2014-01-01

I consider extreme returns for the stock and bond markets of 14 EU countries using two classification schemes: One, the univariate classification scheme from the previous literature that classifies extreme returns for each market separately, and two, a novel multivariate classification scheme tha...

Medical and psychosocial implications of adolescent extreme obesity – acceptance and effects of structured care, short: Youth with Extreme Obesity Study (YES)

Science.gov (United States)

2013-01-01

Background Prevalence rates of overweight and obesity have increased in German children and adolescents in the last three decades. Adolescents with extreme obesity represent a distinct risk group. On the basis of data obtained by the German Child and Youth Survey (KiGGS) and the German district military offices we estimate that the group of extremely obese adolescents (BMI ≥ 35 kg/m2) currently encompasses approximately 200.000 adolescents aged 14 to 21 yrs. Conventional approaches focusing on weight reduction have largely proven futile for them. In addition, only a small percentage of adolescents with extreme obesity seek actively treatment for obesity while contributing disproportionately strong to health care costs. Because of somatic and psychiatric co-morbidities and social problems adolescents with extreme obesity require special attention within the medical care system. We have initiated the project “Medical and psychosocial implications of adolescents with extreme obesity - acceptance and effects of structured care, short: ‘Youths with Extreme Obesity Study (YES)’”, which aims at improving the medical care and social support structures for youths with extreme obesity in Germany. Methods/Design We focus on identification of these subjects (baseline examination) and their acceptance of diagnostic and subsequent treatment procedures. In a randomized controlled trial (RCT) we will investigate the effectiveness of a low key group intervention not focusing on weight loss but aimed at the provision of obesity related information, alleviation of social isolation, school and vocational integration and improvement of self-esteem in comparison to a control group treated in a conventional way with focus on weight loss. Interested individuals who fulfill current recommended criteria for weight loss surgery will be provided with a structured preparation and follow-up programs. All subjects will be monitored within a long-term observational study to

21st Century Changes in Precipitation Extremes Based on Resolved Atmospheric Patterns

Science.gov (United States)

Gao, X.; Schlosser, C. A.; O'Gorman, P. A.; Monier, E.

2014-12-01

Global warming is expected to alter the frequency and/or magnitude of extreme precipitation events. Such changes could have substantial ecological, economic, and sociological consequences. However, climate models in general do not correctly reproduce the frequency distribution of precipitation, especially at the regional scale. In this study, a validated analogue method is employed to diagnose the potential future shifts in the probability of extreme precipitation over the United States under global warming. The method is based on the use of the resolved large-scale meteorological conditions (i.e. flow features, moisture supply) to detect the occurrence of extreme precipitation. The CMIP5 multi-model projections have been compiled for two radiative forcing scenarios (Representative Concentration Pathways 4.5 and 8.5). We further analyze the accompanying circulation features and their changes that may be responsible for shifts in extreme precipitation in response to changed climate. The application of such analogue method to detect other types of hazard events, i.e. landslides is also explored. The results from this study may guide hazardous weather watches and help society develop adaptive strategies for preventing catastrophic losses.

Frontier of plasma physics. 'Research network on non-equilibrium and extreme state plasmas'

International Nuclear Information System (INIS)

Itoh, Sanae-I.; Fujisawa, Akihide; Kodama, Ryosuke; Sato, Motoyasu; Tanaka, Kazuo A.; Hatakeyama, Rikizo; Itoh, Kimitaka

2011-01-01

Plasma physics and fusion science have been applied to a wide variety of plasmas such as nuclear fusion plasmas, high-energy-density plasmas, processing plasmas and nanobio- plasmas. They are pioneering science and technology frontiers such as new energy sources and new functional materials. A large project 'research network on non-equilibrium and extreme state plasmas' is being proposed to reassess individual plasma researches from a common view of the non-equilibrium extreme plasma and to promote collaboration among plasma researchers all over the country. In the present review, recent collaborative works related to this project are being introduced. (T.I.)

Richest Planetary System Discovered - Up to seven planets orbiting a Sun-like star

Science.gov (United States)

2010-08-01

seven planets orbiting HD 10180: probing the architecture of low-mass planetary systems" by C. Lovis et al.). The team is composed of C. Lovis, D. Ségransan, M. Mayor, S. Udry, F. Pepe, and D. Queloz (Observatoire de Genève, Université de Genève, Switzerland), W. Benz (Universität Bern, Switzerland), F. Bouchy (Institut d'Astrophysique de Paris, France), C. Mordasini (Max-Planck-Institut für Astronomie, Heidelberg, Germany), N. C. Santos (Universidade do Porto, Portugal), J. Laskar (Observatoire de Paris, France), A. Correia (Universidade de Aveiro, Portugal), and J.-L. Bertaux (Université Versailles Saint-Quentin, France) and G. Lo Curto (ESO). ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and VISTA, the world's largest survey telescope. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".

iPTF17cw: An Engine-driven Supernova Candidate Discovered Independent of a Gamma-Ray Trigger

International Nuclear Information System (INIS)

Corsi, A.; Palliyaguru, N. T.; Cenko, S. B.; Singer, L. P.; Kutyrev, A.; Kasliwal, M. M.; Kulkarni, S. R.; Blagorodnova, N.; Kupfer, T.; Vedantham, H.; Quimby, R.; Frail, D. A.; Goldstein, A. M.; Connaughton, V.; Perley, D. A.; Copperwheat, C. M.; Piascik, A. S.; Steele, I. A.; Fremling, C.; Taddia, F.

2017-01-01

We present the discovery, classification, and radio-to-X-ray follow-up observations of iPTF17cw, a broad-lined (BL) type Ic supernova (SN) discovered by the intermediate Palomar Transient Factory (iPTF). Although it is unrelated to the gravitational wave trigger, this SN was discovered as a happy by-product of the extensive observational campaign dedicated to the follow-up of Advanced LIGO event GW 170104. The spectroscopic properties and inferred peak bolometric luminosity of iPTF17cw are most similar to the gamma-ray-burst (GRB)-associated SN, SN 1998bw, while the shape of the r -band light curve is most similar to that of the relativistic SN, SN 2009bb. Karl G. Jansky Very Large Array (VLA) observations of the iPTF17cw field reveal a radio counterpart ≈10 times less luminous than SN 1998bw, and with a peak radio luminosity comparable to that of SN 2006aj/GRB 060218 and SN 2010bh/GRB 100316D. Our radio observations of iPTF17cw imply a relativistically expanding outflow. However, further late-time observations with the VLA in its most extended configuration are needed to confirm fading of the iPTF17cw radio counterpart at all frequencies. X-ray observations carried out with Chandra reveal the presence of an X-ray counterpart with a luminosity similar to that of SN 2010bh/GRB 100316D. Searching the Fermi catalog for possible γ -rays reveals that GRB 161228B is spatially and temporally compatible with iPTF17cw. The similarity to SN 1998bw and SN 2009bb, the radio and X-ray detections, and the potential association with GRB 161228B all point to iPTF17cw being a new candidate member of the rare sample of optically discovered engine-driven BL-Ic SNe associated with relativistic ejecta.

iPTF17cw: An Engine-driven Supernova Candidate Discovered Independent of a Gamma-Ray Trigger

Energy Technology Data Exchange (ETDEWEB)

Corsi, A.; Palliyaguru, N. T. [Department of Physics and Astronomy, Texas Tech University, Box 1051, Lubbock, TX 79409-1051 (United States); Cenko, S. B.; Singer, L. P.; Kutyrev, A. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kasliwal, M. M.; Kulkarni, S. R.; Blagorodnova, N.; Kupfer, T.; Vedantham, H. [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Quimby, R. [Department of Astronomy/Mount Laguna Observatory, San Diego State University, San Diego, CA 92182 (United States); Frail, D. A. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Goldstein, A. M.; Connaughton, V. [Universities Space Research Association, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Perley, D. A.; Copperwheat, C. M.; Piascik, A. S.; Steele, I. A. [Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool, L3 5RF (United Kingdom); Fremling, C.; Taddia, F., E-mail: alessandra.corsi@ttu.edu [Oskar Klein Centre, Department of Astronomy, Stockholm University, Albanova University Centre, SE-106 91 Stockholm (Sweden); and others

2017-09-20

We present the discovery, classification, and radio-to-X-ray follow-up observations of iPTF17cw, a broad-lined (BL) type Ic supernova (SN) discovered by the intermediate Palomar Transient Factory (iPTF). Although it is unrelated to the gravitational wave trigger, this SN was discovered as a happy by-product of the extensive observational campaign dedicated to the follow-up of Advanced LIGO event GW 170104. The spectroscopic properties and inferred peak bolometric luminosity of iPTF17cw are most similar to the gamma-ray-burst (GRB)-associated SN, SN 1998bw, while the shape of the r -band light curve is most similar to that of the relativistic SN, SN 2009bb. Karl G. Jansky Very Large Array (VLA) observations of the iPTF17cw field reveal a radio counterpart ≈10 times less luminous than SN 1998bw, and with a peak radio luminosity comparable to that of SN 2006aj/GRB 060218 and SN 2010bh/GRB 100316D. Our radio observations of iPTF17cw imply a relativistically expanding outflow. However, further late-time observations with the VLA in its most extended configuration are needed to confirm fading of the iPTF17cw radio counterpart at all frequencies. X-ray observations carried out with Chandra reveal the presence of an X-ray counterpart with a luminosity similar to that of SN 2010bh/GRB 100316D. Searching the Fermi catalog for possible γ -rays reveals that GRB 161228B is spatially and temporally compatible with iPTF17cw. The similarity to SN 1998bw and SN 2009bb, the radio and X-ray detections, and the potential association with GRB 161228B all point to iPTF17cw being a new candidate member of the rare sample of optically discovered engine-driven BL-Ic SNe associated with relativistic ejecta.

Inter-comparison of statistical downscaling methods for projection of extreme precipitation in Europe

DEFF Research Database (Denmark)

Sunyer Pinya, Maria Antonia; Hundecha, Y.; Lawrence, D.

2015-01-01

Information on extreme precipitation for future climate is needed to assess the changes in the frequency and intensity of flooding. The primary source of information in climate change impact studies is climate model projections. However, due to the coarse resolution and biases of these models......), three are bias correction (BC) methods, and one is a perfect prognosis method. The eight methods are used to downscale precipitation output from 15 regional climate models (RCMs) from the ENSEMBLES project for 11 catchments in Europe. The overall results point to an increase in extreme precipitation...... that at least 30% and up to approximately half of the total variance is derived from the SDMs. This study illustrates the large variability in the expected changes in extreme precipitation and highlights the need for considering an ensemble of both SDMs and climate models. Recommendations are provided...

Large wood recruitment processes and transported volumes in Swiss mountain streams during the extreme flood of August 2005

Science.gov (United States)

Steeb, Nicolas; Rickenmann, Dieter; Badoux, Alexandre; Rickli, Christian; Waldner, Peter

2017-02-01

The extreme flood event that occurred in August 2005 was the most costly (documented) natural hazard event in the history of Switzerland. The flood was accompanied by the mobilization of > 69,000 m3 of large wood (LW) throughout the affected area. As recognized afterward, wood played an important role in exacerbating the damages, mainly because of log jams at bridges and weirs. The present study aimed at assessing the risk posed by wood in various catchments by investigating the amount and spatial variability of recruited and transported LW. Data regarding LW quantities were obtained by field surveys, remote sensing techniques (LiDAR), and GIS analysis and was subsequently translated into a conceptual model of wood transport mass balance. Detailed wood budgets and transport diagrams were established for four study catchments of Swiss mountain streams, showing the spatial variability of LW recruitment and deposition. Despite some uncertainties with regard to parameter assumptions, the sum of reconstructed wood input and observed deposition volumes agree reasonably well. Mass wasting such as landslides and debris flows were the dominant recruitment processes in headwater streams. In contrast, LW recruitment from lateral bank erosion became significant in the lower part of mountain streams where the catchment reached a size of about 100 km2. According to our analysis, 88% of the reconstructed total wood input was fresh, i.e., coming from living trees that were recruited from adjacent areas during the event. This implies an average deadwood contribution of 12%, most of which was estimated to have been in-channel deadwood entrained during the flood event.

Neuromuscular Consequences of an Extreme Mountain Ultra-Marathon

Science.gov (United States)

Millet, Guillaume Y.; Tomazin, Katja; Verges, Samuel; Vincent, Christopher; Bonnefoy, Régis; Boisson, Renée-Claude; Gergelé, Laurent; Féasson, Léonard; Martin, Vincent

2011-01-01

We investigated the physiological consequences of one of the most extreme exercises realized by humans in race conditions: a 166-km mountain ultra-marathon (MUM) with 9500 m of positive and negative elevation change. For this purpose, (i) the fatigue induced by the MUM and (ii) the recovery processes over two weeks were assessed. Evaluation of neuromuscular function (NMF) and blood markers of muscle damage and inflammation were performed before and immediately following (n = 22), and 2, 5, 9 and 16 days after the MUM (n = 11) in experienced ultra-marathon runners. Large maximal voluntary contraction decreases occurred after MUM (−35% [95% CI: −28 to −42%] and −39% [95% CI: −32 to −46%] for KE and PF, respectively), with alteration of maximal voluntary activation, mainly for KE (−19% [95% CI: −7 to −32%]). Significant modifications in markers of muscle damage and inflammation were observed after the MUM as suggested by the large changes in creatine kinase (from 144±94 to 13,633±12,626 UI L−1), myoglobin (from 32±22 to 1,432±1,209 µg L−1), and C-Reactive Protein (from <2.0 to 37.7±26.5 mg L−1). Moderate to large reductions in maximal compound muscle action potential amplitude, high-frequency doublet force, and low frequency fatigue (index of excitation-contraction coupling alteration) were also observed for both muscle groups. Sixteen days after MUM, NMF had returned to initial values, with most of the recovery process occurring within 9 days of the race. These findings suggest that the large alterations in NMF after an ultra-marathon race are multi-factorial, including failure of excitation-contraction coupling, which has never been described after prolonged running. It is also concluded that as early as two weeks after such an extreme running exercise, maximal force capacities have returned to baseline. PMID:21364944

Probabilistic analysis of extreme wind events

Energy Technology Data Exchange (ETDEWEB)

Chaviaropoulos, P.K. [Center for Renewable Energy Sources (CRES), Pikermi Attikis (Greece)

1997-12-31

A vital task in wind engineering and meterology is to understand, measure, analyse and forecast extreme wind conditions, due to their significant effects on human activities and installations like buildings, bridges or wind turbines. The latest version of the IEC standard (1996) pays particular attention to the extreme wind events that have to be taken into account when designing or certifying a wind generator. Actually, the extreme wind events within a 50 year period are those which determine the ``static`` design of most of the wind turbine components. The extremes which are important for the safety of wind generators are those associated with the so-called ``survival wind speed``, the extreme operating gusts and the extreme wind direction changes. A probabilistic approach for the analysis of these events is proposed in this paper. Emphasis is put on establishing the relation between extreme values and physically meaningful ``site calibration`` parameters, like probability distribution of the annual wind speed, turbulence intensity and power spectra properties. (Author)

Influence of the control system on wind turbine loads during power production in extreme turbulence: Structural reliability

DEFF Research Database (Denmark)

Abdallah, Imad; Natarajan, Anand; Sørensen, John Dalsgaard

2016-01-01

structural reliability are assessed when the extreme turbulence model is uncertain. The structural reliability is assessed for the wind turbine when three configurations of an industrial grade load alleviation control system of increasing complexity and performance are used. The load alleviation features......The wind energy industry is continuously researching better computational models of wind inflow and turbulence to predict extreme loading (the nature of randomness) and their corresponding probability of occurrence. Sophisticated load alleviation control systems are increasingly being designed...... and deployed to specifically reduce the adverse effects of extreme load events resulting in lighter structures. The main objective herein is to show that despite large uncertainty in the extreme turbulence models, advanced load alleviation control systems yield both a reduction in magnitude and scatter...

TOLNet ozone lidar intercomparison during the discover-aq and frappé campaigns

Science.gov (United States)

Newchurch, Michael J.; Alvarez, Raul J.; Berkoff, Timothy A.; Carrion, William; DeYoung, Russell J.; Ganoe, Rene; Gronoff, Guillaume; Kirgis, Guillaume; Kuang, Shi; Langford, Andy O.; Leblanc, Thierry; McGee, Thomas J.; Pliutau, Denis; Senff, Christoph; Sullivan, John T.; Sumnicht, Grant; Twigg, Laurence W.; Wang, Lihua

2018-04-01

The Tropospheric Ozone Lidar Network (TOLNet) is a unique network of lidar systems that measure atmospheric profiles of ozone and aerosols, to contribute to air-quality studies, atmospheric modeling, and satellite validation efforts. The accurate characterization of these lidars is of critical interest, and is necessary to determine cross-instrument calibration uniformity. From July to August 2014, three lidars, the TROPospheric OZone (TROPOZ) lidar, the Tunable Optical Profiler for Aerosol and oZone (TOPAZ) lidar, and the Langley Mobile Ozone Lidar (LMOL), of TOLNet participated in the "Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality" (DISCOVER-AQ) mission and the "Front Range Air Pollution and Photochemistry Éxperiment" (FRAPPÉ) to measure sub-hourly ozone variations from near the surface to the top of the troposphere. Although large differences occur at few individual altitudes in the near field and far field range, the TOLNet lidars agree with each other within ±4%. These results indicate excellent measurement accuracy for the TOLNet lidars that is suitable for use in air-quality and ozone modeling efforts.

A novel tree-based algorithm to discover seismic patterns in earthquake catalogs

Science.gov (United States)

Florido, E.; Asencio-Cortés, G.; Aznarte, J. L.; Rubio-Escudero, C.; Martínez-Álvarez, F.

2018-06-01

A novel methodology is introduced in this research study to detect seismic precursors. Based on an existing approach, the new methodology searches for patterns in the historical data. Such patterns may contain statistical or soil dynamics information. It improves the original version in several aspects. First, new seismicity indicators have been used to characterize earthquakes. Second, a machine learning clustering algorithm has been applied in a very flexible way, thus allowing the discovery of new data groupings. Third, a novel search strategy is proposed in order to obtain non-overlapped patterns. And, fourth, arbitrary lengths of patterns are searched for, thus discovering long and short-term behaviors that may influence in the occurrence of medium-large earthquakes. The methodology has been applied to seven different datasets, from three different regions, namely the Iberian Peninsula, Chile and Japan. Reported results show a remarkable improvement with respect to the former version, in terms of all evaluated quality measures. In particular, the number of false positives has decreased and the positive predictive values increased, both of them in a very remarkable manner.

Discovering Multidimensional Structure in Relational Data

DEFF Research Database (Denmark)

Jensen, Mikael Rune; Holmgren, Thomas; Pedersen, Torben Bach

2004-01-01

On-Line Analytical Processing (OLAP) systems based on multidimensional databases are essential elements of decision support. However, most existing data is stored in “ordinary” relational OLTP databases, i.e., data has to be (re-) modeled as multidimensional cubes before the advantages of OLAP to...... algorithms for discovering multidimensional schemas from relational databases. The algorithms take a wide range of available metadata into account in the discovery process, including functional and inclusion dependencies, and key and cardinality information....... tools are available. In this paper we present an approach for the automatic construction of multidimensional OLAP database schemas from existing relational OLTP databases, enabling easy OLAP design and analysis for most existing data sources. This is achieved through a set of practical and effective...

Discovering the Library with Google Earth

Directory of Open Access Journals (Sweden)

Michaela Brenner

2008-06-01

Full Text Available Libraries need to provide attractive and exciting discovery tools to draw patrons to the valuable resources in their catalogs. The authors conducted a pilot project to explore the free version of Google Earth as such a discover tool for Portland State Library’s digital collection of urban planning documents. They created eye-catching placemarks with links to parts of this collection, as well as to other pertinent materials like books, images, and historical background information. The detailed how-to-do part of this article is preceded by a discussion about discovery of library materials and followed by possible applications of this Google Earth project.

Extreme groundwater levels caused by extreme weather conditions - the highest ever measured groundwater levels in Middle Germany and their management

Science.gov (United States)

Reinstorf, F.; Kramer, S.; Koch, T.; Pfützner, B.

2017-12-01

Extreme weather conditions during the years 2009 - 2011 in combination with changes in the regional water management led to maximum groundwater levels in large areas of Germany in 2011. This resulted in extensive water logging, with problems especially in urban areas near rivers, where water logging produced huge problems for buildings and infrastructure. The acute situation still exists in many areas and requires the development of solution concepts. Taken the example of the Elbe-Saale-Region in the Federal State of Saxony-Anhalt, were a pilot research project was carried out, the analytical situation, the development of a management tool and the implementation of a groundwater management concept are shown. The central tool is a coupled water budget - groundwater flow model. In combination with sophisticated multi-scale parameter estimation, a high-resolution groundwater level simulation was carried out. A decision support process with an intensive stakeholder interaction combined with high-resolution simulations enables the development of a management concept for extreme groundwater situations in consideration of sustainable and environmentally sound solutions mainly on the base of passive measures.

Precipitation extremes and their relation to climatic indices in the Pacific Northwest USA

Science.gov (United States)

Zarekarizi, Mahkameh; Rana, Arun; Moradkhani, Hamid

2018-06-01

There has been focus on the influence of climate indices on precipitation extremes in the literature. Current study presents the evaluation of the precipitation-based extremes in Columbia River Basin (CRB) in the Pacific Northwest USA. We first analyzed the precipitation-based extremes using statistically (ten GCMs) and dynamically downscaled (three GCMs) past and future climate projections. Seven precipitation-based indices that help inform about the flood duration/intensity are used. These indices help in attaining first-hand information on spatial and temporal scales for different service sectors including energy, agriculture, forestry etc. Evaluation of these indices is first performed in historical period (1971-2000) followed by analysis of their relation to large scale tele-connections. Further we mapped these indices over the area to evaluate the spatial variation of past and future extremes in downscaled and observational data. The analysis shows that high values of extreme indices are clustered in either western or northern parts of the basin for historical period whereas the northern part is experiencing higher degree of change in the indices for future scenario. The focus is also on evaluating the relation of these extreme indices to climate tele-connections in historical period to understand their relationship with extremes over CRB. Various climate indices are evaluated for their relationship using Principal Component Analysis (PCA) and Singular Value Decomposition (SVD). Results indicated that, out of 13 climate tele-connections used in the study, CRB is being most affected inversely by East Pacific (EP), Western Pacific (WP), East Atlantic (EA) and North Atlaentic Oscillation (NAO).

Stationary and non-stationary extreme value modeling of extreme temperature in Malaysia

Science.gov (United States)

Hasan, Husna; Salleh, Nur Hanim Mohd; Kassim, Suraiya

2014-09-01

Extreme annual temperature of eighteen stations in Malaysia is fitted to the Generalized Extreme Value distribution. Stationary and non-stationary models with trend are considered for each station and the Likelihood Ratio test is used to determine the best-fitting model. Results show that three out of eighteen stations i.e. Bayan Lepas, Labuan and Subang favor a model which is linear in the location parameter. A hierarchical cluster analysis is employed to investigate the existence of similar behavior among the stations. Three distinct clusters are found in which one of them consists of the stations that favor the non-stationary model. T-year estimated return levels of the extreme temperature are provided based on the chosen models.

Cultural diversity in heart failure management: findings from the DISCOVER study (Part 2).

Science.gov (United States)

Davidson, Patricia M; Macdonald, Peter; Moser, Debra K; Ang, Esther; Paull, Glenn; Choucair, Sam; Daly, John; Gholizadeh, Leila; Dracup, Kathleen

2007-01-01

Self-management is a critical dimension in managing chronic conditions, particularly in heart failure (HF). Knowledge, attitudes and beliefs, relating to both illness and wellness, are strongly influenced by culture and ethnicity, impacting upon an individual's capacity to engage in self-care behaviours. Effective management of HF is largely dependent on facilitation of culturally informed, self-care behaviours to increase adherence to both pharmacological and non-pharmacological strategies. The Understanding the cultural experiences of individuals with chronic heart failure (CHF) in South East Health (DISCOVER) study is an exploratory, observational study investigating health patterns, information needs and the adjustment process for overseas-born people with HF living in Australia. An integrative literature review was augmented by qualitative data derived from key informant interviews, focus groups and individual interviews. A key finding of this study is that culture provides an important context to aid interpretations of attitudes, values, beliefs and behaviours, not only in illness but in health. While individual differences in attitudes and beliefs were observed among participants, common themes and issues were identified across cultural groups. Data from the DISCOVER study revealed the primacy of family and kinship ties. These relationships were important in making decisions about treatment choices and care plans. Participants also revealed the critical role of the 'family doctor' in assisting people and their families in brokering the health care system. In this study, heart disease was considered to be a significant condition but cancer was the condition that people both feared and dreaded the most, despite the high mortality rates of HF. This sample reported that religious and traditional beliefs became more important as people aged and considered their mortality. As HF is predominately a condition of ageing, the information derived from this study will

On Extreme Value Statistics: maximum likelihood; portfolio optimization; extremal rainfall; internet auctions

NARCIS (Netherlands)

C. Zhou (Chen)

2008-01-01

textabstractIn the 18th century, statisticians sometimes worked as consultants to gamblers. In order to answer questions like "If a fair coin is flipped 100 times, what is the probability of getting 60 or more heads?", Abraham de Moivre discovered the so-called "normal curve". Independently,

Computational data sciences for assessment and prediction of climate extremes

Science.gov (United States)

Ganguly, A. R.

2011-12-01

Climate extremes may be defined inclusively as severe weather events or large shifts in global or regional weather patterns which may be caused or exacerbated by natural climate variability or climate change. This area of research arguably represents one of the largest knowledge-gaps in climate science which is relevant for informing resource managers and policy makers. While physics-based climate models are essential in view of non-stationary and nonlinear dynamical processes, their current pace of uncertainty reduction may not be adequate for urgent stakeholder needs. The structure of the models may in some cases preclude reduction of uncertainty for critical processes at scales or for the extremes of interest. On the other hand, methods based on complex networks, extreme value statistics, machine learning, and space-time data mining, have demonstrated significant promise to improve scientific understanding and generate enhanced predictions. When combined with conceptual process understanding at multiple spatiotemporal scales and designed to handle massive data, interdisciplinary data science methods and algorithms may complement or supplement physics-based models. Specific examples from the prior literature and our ongoing work suggests how data-guided improvements may be possible, for example, in the context of ocean meteorology, climate oscillators, teleconnections, and atmospheric process understanding, which in turn can improve projections of regional climate, precipitation extremes and tropical cyclones in an useful and interpretable fashion. A community-wide effort is motivated to develop and adapt computational data science tools for translating climate model simulations to information relevant for adaptation and policy, as well as for improving our scientific understanding of climate extremes from both observed and model-simulated data.

Reoperations following combat-related upper-extremity amputations.

Science.gov (United States)

Tintle, Scott M; Baechler, Martin F; Nanos, George P; Forsberg, Jonathan A; Potter, Benjamin K

2012-08-15

Amputation revision rates following major upper-extremity amputations have not been previously reported in a large cohort of patients. We hypothesized that the revision rates following major upper-extremity amputation were higher than the existing literature would suggest, and that surgical treatment of complications and persistent symptoms would lead to improved outcomes. We performed a retrospective analysis of a consecutive series of ninety-six combat-wounded personnel who had sustained a total of 100 major upper-extremity amputations in Operation Iraqi Freedom and Operation Enduring Freedom. Prerevision and postrevision outcome measures, including prosthesis use and type, the presence of phantom and residual limb pain, pain medication use, and return to active military duty, were identified for all patients. All amputations resulted from high-energy trauma, with 87% occurring secondary to a blast injury. Forty-two residual limbs (42%) underwent a total of 103 repeat surgical interventions. As compared with patients with all other levels of amputation, those with a transradial amputation were 4.7 (95% confidence interval [CI]: 1.75 to 12.46) times more likely to have phantom limb pain and 2.8 (95% CI: 1.04 to 7.39) times more likely to require neuropathic pain medications. In the group of patients who underwent revision surgery, regular prosthesis use increased from 19% before the revision to 87% after it (p < 0.0001). In our cohort, revision amputation to address surgical complications and persistently symptomatic residual limbs improved the patient's overall acceptance of the prosthesis and led to outcomes equivalent to those following amputations that did not require revision.

A note on extreme sets

Directory of Open Access Journals (Sweden)

Radosław Cymer

2017-10-01

Full Text Available In decomposition theory, extreme sets have been studied extensively due to its connection to perfect matchings in a graph. In this paper, we first define extreme sets with respect to degree-matchings and next investigate some of their properties. In particular, we prove the generalized Decomposition Theorem and give a characterization for the set of all extreme vertices in a graph.

Peculiarities of the propagation of multidimensional extremely short optical pulses in germanene

Energy Technology Data Exchange (ETDEWEB)

Zhukov, Alexander V., E-mail: alex_zhukov@sutd.edu.sg [Singapore University of Technology and Design, 8 Somapah Road, 487372 Singapore (Singapore); Bouffanais, Roland [Singapore University of Technology and Design, 8 Somapah Road, 487372 Singapore (Singapore); Konobeeva, Natalia N. [Volgograd State University, 400062 Volgograd (Russian Federation); Belonenko, Mikhail B. [Laboratory of Nanotechnology, Volgograd Institute of Business, 400048 Volgograd (Russian Federation); Volgograd State University, 400062 Volgograd (Russian Federation)

2016-09-07

Highlights: • Established dynamics of ultra-short pulses in germanene. • Studied balance between dispersive and nonlinear effects in germanene. • Spin–orbit interaction effect onto pulse propagation. - Abstract: In this Letter, we study the propagation characteristics of both two-dimensional and three-dimensional extremely short optical pulses in germanene. A distinguishing feature of germanene—in comparison with other graphene-like structures—is the presence of a significant spin–orbit interaction. The account of this interaction has a significant impact on the evolution of extremely short pulses in such systems. Specifically, extremely short optical pulses, consisting of two electric field oscillations, cause the appearance of a tail associated with the excitation of nonlinear waves. Due to the large spin–orbit interaction in germanene, this tail behind the main pulse is much smaller in germanene-based samples as compared to graphene-based ones, thereby making germanene a preferred material for the stable propagation of pulses along the sample.

Extremal dyonic black holes in D=4 Gauss-Bonnet gravity

International Nuclear Information System (INIS)

Chen, C.-M.; Gal'tsov, Dmitri V.; Orlov, Dmitry G.

2008-01-01

We investigate extremal dyon black holes in the Einstein-Maxwell-dilaton theory with higher curvature corrections in the form of the Gauss-Bonnet density coupled to the dilaton. In the same theory without the Gauss-Bonnet term the extremal dyon solutions exist only for discrete values of the dilaton coupling constant a. We show that the Gauss-Bonnet term acts as a dyon hair tonic enlarging the allowed values of a to continuous domains in the plane (a,q m ) where q m is the magnetic charge. In the limit of the vanishing curvature coupling (a large magnetic charge) the dyon solutions obtained tend to the Reissner-Nordstroem solution but not to the extremal dyons of the Einstein-Maxwell-dilaton theory. Both solutions have the same dependence of the horizon radius in terms of charges. The entropy of new dyonic black holes interpolates between the Bekenstein-Hawking value in the limit of the large magnetic charge (equivalent to the vanishing Gauss-Bonnet coupling) and twice this value for the vanishing magnetic charge. Although an expression for the entropy can be obtained analytically using purely local near-horizon solutions, its interpretation as the black hole entropy is legitimate only once the global black hole solution is known to exist, and we obtain numerically the corresponding conditions on the parameters. Thus, a purely local analysis is insufficient to fully understand the entropy of the curvature-corrected black holes. We also find dyon solutions which are not asymptotically flat, but approach the linear dilaton background at infinity. They describe magnetic black holes on the electric linear dilaton background.

Extreme Programming: Maestro Style

Science.gov (United States)

Norris, Jeffrey; Fox, Jason; Rabe, Kenneth; Shu, I-Hsiang; Powell, Mark

2009-01-01

"Extreme Programming: Maestro Style" is the name of a computer programming methodology that has evolved as a custom version of a methodology, called extreme programming that has been practiced in the software industry since the late 1990s. The name of this version reflects its origin in the work of the Maestro team at NASA's Jet Propulsion Laboratory that develops software for Mars exploration missions. Extreme programming is oriented toward agile development of software resting on values of simplicity, communication, testing, and aggressiveness. Extreme programming involves use of methods of rapidly building and disseminating institutional knowledge among members of a computer-programming team to give all the members a shared view that matches the view of the customers for whom the software system is to be developed. Extreme programming includes frequent planning by programmers in collaboration with customers, continually examining and rewriting code in striving for the simplest workable software designs, a system metaphor (basically, an abstraction of the system that provides easy-to-remember software-naming conventions and insight into the architecture of the system), programmers working in pairs, adherence to a set of coding standards, collaboration of customers and programmers, frequent verbal communication, frequent releases of software in small increments of development, repeated testing of the developmental software by both programmers and customers, and continuous interaction between the team and the customers. The environment in which the Maestro team works requires the team to quickly adapt to changing needs of its customers. In addition, the team cannot afford to accept unnecessary development risk. Extreme programming enables the Maestro team to remain agile and provide high-quality software and service to its customers. However, several factors in the Maestro environment have made it necessary to modify some of the conventional extreme

Thymolipoma combined with hyperthyroidism discovered by neurological symptoms.

Science.gov (United States)

Takahashi, Hidenobu; Harada, Masahiko; Kimura, Masakazu; Kato, Harubumi

2007-04-01

Thymolipomas are rare slow-growing mediastinal thymic neoplasms. Most cases are asymptomatic and are sometimes discovered as a huge mass on chest x-ray films. A few cases have been discovered during examinations for other diseases. We report the second case of thymolipoma combined with hyperthyroidism in the English language literature. Neurological symptoms suddenly appeared in a 45-year-old woman. Central nervous system disorder was suggested but no significant abnormalities were found on brain MR nor were there any neurological signs. Several months later, neurological and systemic examinations on admission revealed hyperthyroidism and an anterior mediastinal tumor, 9.0x5.0x3.0 cm in size on chest CT films. Despite treatment of hyperthyroidism by medication, her neurological symptoms remained. Neurologists recommended resection of the mediastinal tumor. Malignancy could not be ruled out because of the irregularity of the tumor appearance on contrast-enhanced chest CT. Furthermore, the tumor appeared to be attached to the ascending aorta, so cytological and/or pathological diagnosis by CT-guided needle biopsy before operation were contraindicated. Extended thymectomy was performed in May 2005. The pathological diagnosis was benign thymolipoma consisting of mature fatty tissue and thymic tissue structures with Hassall's corpuscles. Her neurological symptoms seemed slightly but not markedly improved. The relationship between thymolipoma and hyperthyroidism is still unknown.

Extremity exposure in nuclear medicine: Preliminary results of a European study

International Nuclear Information System (INIS)

Merce, M. S.; Ruiz, N.; Barth, I.; Carnicer, A.; Donadille, L.; Ferrari, P.; Fulop, M.; Ginjaume, M.; Gualdrini, G.; Krim, S.; Mariotti, F.; Ortega, X.; Rimpler, A.; Vanhavere, F.; Baechler, S.

2011-01-01

The Work Package 4 of the ORAMED project, a collaborative project (2008-11) supported by the European Commission within its seventh Framework Programme, is concerned with the optimisation of the extremity dosimetry of medical staff in nuclear medicine. To evaluate the extremity doses and dose distributions across the hands of medical staff working in nuclear medicine departments, an extensive measurement programme has been started in 32 nuclear medicine departments in Europe. This was done using a standard protocol recording all relevant information for radiation exposure, i.e. radiation protection devices and tools. This study shows the preliminary results obtained for this measurement campaign. For diagnostic purposes, the two most-used radionuclides were considered: 99m Tc) and 18 F. For therapeutic treatments, Zevalin R and DOTATOC (both labelled with 90 Y) were chosen. Large variations of doses were observed across the hands depending on different parameters. Furthermore, this study highlights the importance of the positioning of the extremity dosemeter for a correct estimate of the maximum skin doses. (authors)

Discovering and Exploring State-based Models for Multi-perspective Processes

NARCIS (Netherlands)

van Eck, M.L.; Sidorova, N.; van der Aalst, W.M.P.; La Rosa, M.; Loos, P.; Pastor, O.

2016-01-01

Process mining provides fact-based insights into process behaviour captured in event data. In this work we aim to discover models for processes where different facets, or perspectives, of the process can be identified. Instead of focussing on the events or activities that are executed in the context

Extremely deformable structures

CERN Document Server

2015-01-01

Recently, a new research stimulus has derived from the observation that soft structures, such as biological systems, but also rubber and gel, may work in a post critical regime, where elastic elements are subject to extreme deformations, though still exhibiting excellent mechanical performances. This is the realm of ‘extreme mechanics’, to which this book is addressed. The possibility of exploiting highly deformable structures opens new and unexpected technological possibilities. In particular, the challenge is the design of deformable and bi-stable mechanisms which can reach superior mechanical performances and can have a strong impact on several high-tech applications, including stretchable electronics, nanotube serpentines, deployable structures for aerospace engineering, cable deployment in the ocean, but also sensors and flexible actuators and vibration absorbers. Readers are introduced to a variety of interrelated topics involving the mechanics of extremely deformable structures, with emphasis on ...

Are rheumatoid arthritis patients discernible from other early arthritis patients using 1.5T extremity magnetic resonance imaging? a large cross-sectional study.

Science.gov (United States)

Stomp, Wouter; Krabben, Annemarie; van der Heijde, Désirée; Huizinga, Tom W J; Bloem, Johan L; van der Helm-van Mil, Annette H M; Reijnierse, Monique

2014-08-01

Magnetic resonance imaging (MRI) is increasingly used in rheumatoid arthritis (RA) research. A European League Against Rheumatism (EULAR) task force recently suggested that MRI can improve the certainty of RA diagnosis. Because this recommendation may reflect a tendency to use MRI in daily practice, thorough studies on the value of MRI are required. Thus far no large studies have evaluated the accuracy of MRI to differentiate early RA from other patients with early arthritis. We performed a large cross-sectional study to determine whether patients who are clinically classified with RA differ in MRI features compared to patients with other diagnoses. In our study, 179 patients presenting with early arthritis (median symptom duration 15.4 weeks) underwent 1.5T extremity MRI of unilateral wrist, metacarpophalangeal, and metatarsophalangeal joints according to our arthritis protocol, the foot without contrast. Images were scored according to OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Scoring (RAMRIS) by 2 independent readers. Tenosynovitis was also assessed. The main outcome was fulfilling the 1987 American College of Rheumatology (ACR) criteria for RA. Test characteristics and areas under the receiver-operator-characteristic curves (AUC) were evaluated. In subanalyses, the 2010 ACR/EULAR criteria were used as outcome, and analyses were stratified for anticitrullinated protein antibodies (ACPA). The ACR 1987 criteria were fulfilled in 43 patients (24.0%). Patients with RA had higher scores for synovitis, tenosynovitis, and bone marrow edema (BME) than patients without RA (p arthritis patients.

Lower extremity finite element model for crash simulation