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Sample records for include frequency distribution

  1. Allele frequency distribution of 1691G >A F5 (which confers Factor V Leiden) across Europe, including Slavic populations.

    Science.gov (United States)

    Clark, Jeremy S C; Adler, Grażyna; Salkic, Nermin N; Ciechanowicz, Andrzej

    2013-11-01

    The allele 1691A F5, conferring Factor V Leiden, is a common risk factor in venous thromboembolism. The frequency distribution for this allele in Western Europe has been well documented; but here data from Central, Eastern and South-Eastern Europe has been included. In order to assess the significance of the collated data, a chi-squared test was applied, and Tukey tests and z-tests with Bonferroni correction were compared. A distribution with a North-Southeast band of high frequency of the 1691A F5 allele was discovered with a pocket including some Southern Slavic populations with low frequency. European countries/regions can be arbitrarily delimited into low (group 1, <2.8 %, mean 1.9 % 1691A F5 allele) or high (group 2, ≥2.8 %, mean 4.0 %) frequency groups, with many significant differences between groups, but only one intra-group difference (the Tukey test is suggested to be superior to the z-tests). In Europe a North-Southeast band of 1691A F5 high frequency has been found, clarified by inclusion of data from Central, Eastern and South-Eastern Europe, which surrounds a pocket of low frequency in the Balkans which could possibly be explained by Slavic migration. There seem to be no indications of variation in environmental selection due to geographical location.

  2. Robust Unit Commitment Including Frequency Stability Constraints

    Directory of Open Access Journals (Sweden)

    Felipe Pérez-Illanes

    2016-11-01

    Full Text Available An increased use of variable generation technologies such as wind power and photovoltaic generation can have important effects on system frequency performance during normal operation as well as contingencies. The main reasons are the operational principles and inherent characteristics of these power plants like operation at maximum power point and no inertial response during power system imbalances. This has led to new challenges for Transmission System Operators in terms of ensuring system security during contingencies. In this context, this paper proposes a Robust Unit Commitment including a set of additional frequency stability constraints. To do this, a simplified dynamic model of the initial system frequency response is used in combination with historical frequency nadir data during contingencies. The proposed approach is especially suitable for power systems with cost-based economic dispatch like those in most Latin American countries. The study is done considering the Northern Interconnected System of Chile, a 50-Hz medium size isolated power system. The results obtained were validated by means of dynamic simulations of different system contingencies.

  3. Global Multihazard Frequency and Distribution

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Multihazard Frequency and Distribution is a 2.5 minute grid presenting a simple multihazard index based solely on summated single-hazard decile values. The...

  4. NASA/DOD Aerospace Knowledge Diffusion Research Project. Report 10: Summary report to phase 3 academic library respondents including frequency distributions

    Science.gov (United States)

    Pinelli, Thomas E.; Kennedy, John M.; White, Terry F.

    1991-01-01

    Phase 3 of a 4 part study was undertaken to study the use of scientific and technical information (STI) in the academic aerospace community. Phase 3 of this project used three questionnaires that were sent to three groups (i.e., faculty, librarians, and students) in the academic aerospace community. Specific attention was paid to the types of STI used and the methods in which academic users acquire STI. The responses of the academic libraries are focussed on herein. Demographic information on academic aerospace libraries is provided. Data regarding NASA interaction with academic aerospace libraries is also included, as is the survey instrument.

  5. High frequency power distribution system

    Science.gov (United States)

    Patel, Mikund R.

    1986-01-01

    The objective of this project was to provide the technology of high frequency, high power transmission lines to the 100 kW power range at 20 kHz frequency. In addition to the necessary design studies, a 150 m long, 600 V, 60 A transmission line was built, tested and delivered for full vacuum tests. The configuration analysis on five alternative configurations resulted in the final selection of the three parallel Litz straps configuration, which gave a virtually concentric design in the electromagnetic sense. Low inductance, low EMI and flexibility in handling are the key features of this configuration. The final design was made after a parametric study to minimize the losses, weight and inductance. The construction of the cable was completed with no major difficulties. The R,L,C parameters measured on the cable agreed well with the calculated values. The corona tests on insulation samples showed a safety factor of 3.

  6. Nonlinear Progressive Collapse Analysis Including Distributed Plasticity

    Directory of Open Access Journals (Sweden)

    Mohamed Osama Ahmed

    2016-01-01

    Full Text Available This paper demonstrates the effect of incorporating distributed plasticity in nonlinear analytical models used to assess the potential for progressive collapse of steel framed regular building structures. Emphasis on this paper is on the deformation response under the notionally removed column, in a typical Alternate Path (AP method. The AP method employed in this paper is based on the provisions of the Unified Facilities Criteria – Design of Buildings to Resist Progressive Collapse, developed and updated by the U.S. Department of Defense [1]. The AP method is often used for to assess the potential for progressive collapse of building structures that fall under Occupancy Category III or IV. A case study steel building is used to examine the effect of incorporating distributed plasticity, where moment frames were used on perimeter as well as the interior of the three dimensional structural system. It is concluded that the use of moment resisting frames within the structural system will enhance resistance to progressive collapse through ductile deformation response and that it is conserative to ignore the effects of distributed plasticity in determining peak displacement response under the notionally removed column.

  7. Global Volcano Hazard Frequency and Distribution

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Volcano Hazard Frequency and Distribution is a 2.5 minute gridded data set based upon the National Geophysical Data Center (NGDC) Volcano Database spanning...

  8. Global Earthquake Hazard Frequency and Distribution

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Earthquake Hazard Frequency and Distribution is a 2.5 by 2.5 minute global utilizing Advanced National Seismic System (ANSS) Earthquake Catalog data of actual...

  9. Global Drought Hazard Frequency and Distribution

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Drought Hazard Frequency and Distribution is a 2.5 minute grid based upon the International Research Institute for Climate Prediction's (IRI) Weighted Anomaly...

  10. Global Earthquake Hazard Frequency and Distribution

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Earthquake Hazard Frequency and Distribution is a 2.5 minute grid utilizing Advanced National Seismic System (ANSS) Earthquake Catalog data of actual...

  11. Global Flood Hazard Frequency and Distribution

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Flood Hazard Frequency and Distribution is a 2.5 minute grid derived from a global listing of extreme flood events between 1985 and 2003 (poor or missing data...

  12. Global Cyclone Hazard Frequency and Distribution

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Cyclone Hazard Frequency and Distribution is a 2.5 minute grid based on more than 1,600 storm tracks for the period 1 January 1980 through 31 December 2000...

  13. Reliability assessment of distribution power systems including distributed generations

    International Nuclear Information System (INIS)

    Megdiche, M.

    2004-12-01

    Nowadays, power systems have reached a good level of reliability. Nevertheless, considering the modifications induced by the connections of small independent producers to distribution networks, there's a need to assess the reliability of these new systems. Distribution networks present several functional characteristics, highlighted by the qualitative study of the failures, as dispersed loads at several places, variable topology and some electrotechnical phenomena which must be taken into account to model the events that can occur. The adopted reliability calculations method is Monte Carlo simulations, the probabilistic method most powerful and most flexible to model complex operating of the distribution system. We devoted a first part on the case of a 20 kV feeder to which a cogeneration unit is connected. The method was applied to a software of stochastic Petri nets simulations. Then a second part related to the study of a low voltage power system supplied by dispersed generations. Here, the complexity of the events required to code the method in an environment of programming allowing the use of power system calculations (load flow, short-circuit, load shedding, management of units powers) in order to analyse the system state for each new event. (author)

  14. Global Cyclone Hazard Frequency and Distribution

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Cyclone Hazard Frequency and Distribution is a 2.5 by 2.5 minute grid based on more than 1,600 storm tracks for the period 1 January 1980 through 31 December...

  15. Inverter design for high frequency power distribution

    Science.gov (United States)

    King, R. J.

    1985-01-01

    A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

  16. Asymptotic Time Averages and Frequency Distributions

    Directory of Open Access Journals (Sweden)

    Muhammad El-Taha

    2016-01-01

    Full Text Available Consider an arbitrary nonnegative deterministic process (in a stochastic setting {X(t,  t≥0} is a fixed realization, i.e., sample-path of the underlying stochastic process with state space S=(-∞,∞. Using a sample-path approach, we give necessary and sufficient conditions for the long-run time average of a measurable function of process to be equal to the expectation taken with respect to the same measurable function of its long-run frequency distribution. The results are further extended to allow unrestricted parameter (time space. Examples are provided to show that our condition is not superfluous and that it is weaker than uniform integrability. The case of discrete-time processes is also considered. The relationship to previously known sufficient conditions, usually given in stochastic settings, will also be discussed. Our approach is applied to regenerative processes and an extension of a well-known result is given. For researchers interested in sample-path analysis, our results will give them the choice to work with the time average of a process or its frequency distribution function and go back and forth between the two under a mild condition.

  17. Stochastic subspace system identification using multivariate time-frequency distributions

    Science.gov (United States)

    Chang, Chia-Ming; Huang, Shieh-Kung

    2017-04-01

    Structural health monitoring assesses structural integrity by processing the measured responses of structures. One particular group in the structural health monitoring research is to conduct the operational modal analysis and then to extract the dynamic characteristics of structures from vibrational responses. These characteristics include natural frequencies, damping ratios, and mode shapes. Deviations in these characteristics represent the changes in structural properties and also imply possible damage to structures. In this study, a new stochastic system identification is developed using multivariate time-frequency distributions. These time-frequency distributions are derived from the short-time Fourier transform and subsequently yield a time-frequency matrix by stacking them with respect to time. As the derivation in the data-driven stochastic subspace system identification, the future time-frequency matrix is projected onto the past time-frequency matrix. By exploiting the singular value decomposition, the system and measurement matrices of a stochastic state-space representation are derived. Consequently, the dynamic characteristics of a structure are obtained. As compared to the time-domain stochastic subspace system identification, the proposed method utilizes the past and future matrices with a lower dimension in projection. A spectral magnitude envelope can be applied to the time-frequency matrix to highlight the major frequency components as well as to eliminate the components with less influence. To validate the proposed method, a numerical example is developed. This method is also applied to experimental data in order to evaluate its effectiveness. As a result, performance of the proposed method is superior to the time-domain stochastic subspace system identification.

  18. Seasonally adjusted birth frequencies follow the Poisson distribution.

    Science.gov (United States)

    Barra, Mathias; Lindstrøm, Jonas C; Adams, Samantha S; Augestad, Liv A

    2015-12-15

    Variations in birth frequencies have an impact on activity planning in maternity wards. Previous studies of this phenomenon have commonly included elective births. A Danish study of spontaneous births found that birth frequencies were well modelled by a Poisson process. Somewhat unexpectedly, there were also weekly variations in the frequency of spontaneous births. Another study claimed that birth frequencies follow the Benford distribution. Our objective was to test these results. We analysed 50,017 spontaneous births at Akershus University Hospital in the period 1999-2014. To investigate the Poisson distribution of these births, we plotted their variance over a sliding average. We specified various Poisson regression models, with the number of births on a given day as the outcome variable. The explanatory variables included various combinations of years, months, days of the week and the digit sum of the date. The relationship between the variance and the average fits well with an underlying Poisson process. A Benford distribution was disproved by a goodness-of-fit test (p variables is significantly improved (p variable. Altogether 7.5% more children are born on Tuesdays than on Sundays. The digit sum of the date is non-significant as an explanatory variable (p = 0.23), nor does it increase the explained variance. INERPRETATION: Spontaneous births are well modelled by a time-dependent Poisson process when monthly and day-of-the-week variation is included. The frequency is highest in summer towards June and July, Friday and Tuesday stand out as particularly busy days, and the activity level is at its lowest during weekends.

  19. Zipfian Frequency Distributions Facilitate Word Segmentation in Context

    Science.gov (United States)

    Kurumada, Chigusa; Meylan, Stephan C.; Frank, Michael C.

    2013-01-01

    Word frequencies in natural language follow a highly skewed Zipfian distribution, but the consequences of this distribution for language acquisition are only beginning to be understood. Typically, learning experiments that are meant to simulate language acquisition use uniform word frequency distributions. We examine the effects of Zipfian…

  20. 21 CFR 179.30 - Radiofrequency radiation for the heating of food, including microwave frequencies.

    Science.gov (United States)

    2010-04-01

    ..., including microwave frequencies. 179.30 Section 179.30 Food and Drugs FOOD AND DRUG ADMINISTRATION... for the heating of food, including microwave frequencies. Radiofrequency radiation, including microwave frequencies, may be safely used for heating food under the following conditions: (a) The radiation...

  1. Blockwise Frequency Domain Active Noise Controller Over Distributed Networks

    Directory of Open Access Journals (Sweden)

    Christian Antoñanzas

    2016-04-01

    Full Text Available This work presents a practical active noise control system composed of distributed and collaborative acoustic nodes. To this end, experimental tests have been carried out in a listening room with acoustic nodes equipped with loudspeakers and microphones. The communication among the nodes is simulated by software. We have considered a distributed algorithm based on the Filtered-x Least Mean Square (FxLMS method that introduces collaboration between nodes following an incremental strategy. For improving the processing efficiency in practical scenarios where data acquisition systems work by blocks of samples, the frequency-domain partitioned block technique has been used. Implementation aspects such as computational complexity, processing time of the network and convergence of the algorithm have been analyzed. Experimental results show that, without constraints in the network communications, the proposed distributed algorithm achieves the same performance as the centralized version. The performance of the proposed algorithm over a network with a given communication delay is also included.

  2. Comparative frequency and allelic distribution of ABO and Rh (D ...

    African Journals Online (AJOL)

    Background: Allelic distribution of major blood groups (ABO and rhesus) has not been defined in Bangladeshi population. Determinants of blood group frequency in this region have not been studied properly. Aim: To determine ABO and rhesus blood group frequency and allelic distribution in a multiethnic area of ...

  3. Comparative frequency and allelic distribution of ABO and Rh (D ...

    African Journals Online (AJOL)

    Gourab Dewan

    2015-02-18

    Feb 18, 2015 ... Abstract Background: Allelic distribution of major blood groups (ABO and rhesus) has not been defined in Bangladeshi population. Determinants of blood group frequency in this region have not been studied properly. Aim: To determine ABO and rhesus blood group frequency and allelic distribution in a.

  4. Single Frequency Network Based Distributed Passive Radar Technology

    Directory of Open Access Journals (Sweden)

    Wan Xian-rong

    2015-01-01

    Full Text Available The research and application of passive radar are heading from single transmitter-receiver pair to multiple transmitter-receiver pairs. As an important class of the illuminators of opportunity, most of modern digital broadcasting and television systems work on Single Frequency Network (SFN, which intrinsically determines that the passive radar based on such illuminators must be distributed and networked. In consideration of the remarkable working and processing mode of passive radar under SFN configuration, this paper proposes the concept of SFN-based Distributed Passive Radar (SDPR. The main characteristics and key problems of SDPR are first described. Then several potential solutions are discussed for part of the key technologies. The feasibility of SDPR is demonstrated by preliminary experimental results. Finally, the concept of four network convergence that includes the broadcast based passive radar network is conceived, and its application prospects are discussed.

  5. Hygroscopicity frequency distributions of secondary organic aerosols

    Science.gov (United States)

    Suda, S. R.; Petters, M. D.; Matsunaga, A.; Sullivan, R. C.; Ziemann, P. J.; Kreidenweis, S. M.

    2012-02-01

    Secondary organic compounds are an important component of ambient aerosol and potentially lower the supersaturation that is required for individual particles to serve as cloud condensation nuclei (CCN). Secondary organic aerosol (SOA) formed from the oxidation of a single precursor can be composed of many different compounds and their overall CCN efficiency has been reported for many different SOA systems. An aerosol's CCN efficiency can be described by a single hygroscopicity parameter, κ. However, this κ comprises an unknown distribution of underlying κ-values resulting from each individual compound in the SOA mixture. Here we report on a new technique for characterizing this distribution ofκ. Precursor hydrocarbons were oxidized in an environmental chamber to form SOA, which was collected on filters and extracted using ethyl acetate. Extracts were then fractionated by reversed-phase high-performance liquid chromatography using gradient elution with acetonitrile and water. The eluate was atomized, the solvent was removed by evaporation, and the residual aerosol particles were analyzed as a function of retention time using scanning flow CCN analysis. Kappa-values generally decreased with component retention time, consistent with expected decreasing polarity. Averaged SOAκ-values reconstructed by integrating over the chromatogram agreed well with values measured for SOA sampled directly from the environmental chamber, suggesting thatκfor SOA represents the volume-weighted average of the constituent compounds'κ-values. We anticipate that our measured hygroscopicity distributions will serve as validation points for mechanistic models that seek to predict the generation and evolution of organic aerosol composition and properties in the atmosphere.

  6. The frequency characteristics of medium voltage distribution system impedances

    Directory of Open Access Journals (Sweden)

    Liviu Emil Petrean

    2009-10-01

    Full Text Available In this paper we present the frequency characteristics of impedances involved in the electrical equivalent circuit of a large medium voltage distribution system. These impedances influence harmonics distortions propagation occurring due to the nonsinusoidal loads. We analyse the case of a 10 kV large urban distribution system which supplies industrial, commercial and residential customers. The influence of various parameters of the distribution network on the frequency characteristics are presented, in order to assess the interaction of harmonic distortion and distribution system network.

  7. Recurrent frequency-size distribution of characteristic events

    Directory of Open Access Journals (Sweden)

    S. G. Abaimov

    2009-04-01

    Full Text Available Statistical frequency-size (frequency-magnitude properties of earthquake occurrence play an important role in seismic hazard assessments. The behavior of earthquakes is represented by two different statistics: interoccurrent behavior in a region and recurrent behavior at a given point on a fault (or at a given fault. The interoccurrent frequency-size behavior has been investigated by many authors and generally obeys the power-law Gutenberg-Richter distribution to a good approximation. It is expected that the recurrent frequency-size behavior should obey different statistics. However, this problem has received little attention because historic earthquake sequences do not contain enough events to reconstruct the necessary statistics. To overcome this lack of data, this paper investigates the recurrent frequency-size behavior for several problems. First, the sequences of creep events on a creeping section of the San Andreas fault are investigated. The applicability of the Brownian passage-time, lognormal, and Weibull distributions to the recurrent frequency-size statistics of slip events is tested and the Weibull distribution is found to be the best-fit distribution. To verify this result the behaviors of numerical slider-block and sand-pile models are investigated and the Weibull distribution is confirmed as the applicable distribution for these models as well. Exponents β of the best-fit Weibull distributions for the observed creep event sequences and for the slider-block model are found to have similar values ranging from 1.6 to 2.2 with the corresponding aperiodicities CV of the applied distribution ranging from 0.47 to 0.64. We also note similarities between recurrent time-interval statistics and recurrent frequency-size statistics.

  8. Word frequencies: A comparison of Pareto type distributions

    Science.gov (United States)

    Wiegand, Martin; Nadarajah, Saralees; Si, Yuancheng

    2018-03-01

    Mehri and Jamaati (2017) [18] used Zipf's law to model word frequencies in Holy Bible translations for one hundred live languages. We compare the fit of Zipf's law to a number of Pareto type distributions. The latter distributions are shown to provide the best fit, as judged by a number of comparative plots and error measures. The fit of Zipf's law appears generally poor.

  9. Biofilms from a Brazilian water distribution system include filamentous fungi.

    Science.gov (United States)

    Siqueira, V M; Oliveira, H M B; Santos, C; Paterson, R R M; Gusmão, N B; Lima, N

    2013-03-01

    Filamentous fungi in drinking water can block water pipes, can cause organoleptic biodeterioration, and are a source of pathogens. There are increasing reports of the involvement of the organisms in biofilms. This present study describes a sampling device that can be inserted directly into pipes within water distribution systems, allowing biofilm formation in situ. Calcofluor White M2R staining and fluorescent in situ hybridization with morphological analyses using epifluorescent microscopy were used to analyse biofilms for filamentous fungi, permitting direct observation of the fungi. DAPI (4',6-diamidino-2-phenylindole) was applied to detect bacteria. Filamentous fungi were detected in biofilms after 6 months on coupons exposed to raw water, decanted water and at the entrance of the water distribution system. Algae, yeast, and bacteria were also observed. The role of filamentous fungi requires further investigations.

  10. Highly flexible distributions to fit multiple frequency financial returns

    Science.gov (United States)

    BenSaïda, Ahmed; Slim, Skander

    2016-01-01

    Financial data are usually studied via low flexible distributions, independently of the frequency of the data, due to their simplicity and analytical tractability. In this paper we analyze two highly flexible five-parameter distributions into fitting financial returns, these are the skewed generalized t (SGT) and the generalized hyperbolic (GH). Applications carried on two exchange rates (Euro-Dollar and Dollar-Yen), and two indexes (S&P 500 and Nikkei 225) over four frequencies: weekly, daily, 30-min and 5-min, confirm the superiority of the SGT and GH in approximating the distribution of a given data at a remarkable precision. Moreover, as we move from higher to lower frequency, the distribution's overall shape does indeed change radically, and the estimated parameters refute the tendency to normality, which calls into question the aggregational Gaussianity's stylized fact.

  11. LPI Radar Waveform Recognition Based on Time-Frequency Distribution

    Directory of Open Access Journals (Sweden)

    Ming Zhang

    2016-10-01

    Full Text Available In this paper, an automatic radar waveform recognition system in a high noise environment is proposed. Signal waveform recognition techniques are widely applied in the field of cognitive radio, spectrum management and radar applications, etc. We devise a system to classify the modulating signals widely used in low probability of intercept (LPI radar detection systems. The radar signals are divided into eight types of classifications, including linear frequency modulation (LFM, BPSK (Barker code modulation, Costas codes and polyphase codes (comprising Frank, P1, P2, P3 and P4. The classifier is Elman neural network (ENN, and it is a supervised classification based on features extracted from the system. Through the techniques of image filtering, image opening operation, skeleton extraction, principal component analysis (PCA, image binarization algorithm and Pseudo–Zernike moments, etc., the features are extracted from the Choi–Williams time-frequency distribution (CWD image of the received data. In order to reduce the redundant features and simplify calculation, the features selection algorithm based on mutual information between classes and features vectors are applied. The superiority of the proposed classification system is demonstrated by the simulations and analysis. Simulation results show that the overall ratio of successful recognition (RSR is 94.7% at signal-to-noise ratio (SNR of −2 dB.

  12. Correcting length-frequency distributions for imperfect detection

    Science.gov (United States)

    Breton, André R.; Hawkins, John A.; Winkelman, Dana L.

    2013-01-01

    Sampling gear selects for specific sizes of fish, which may bias length-frequency distributions that are commonly used to assess population size structure, recruitment patterns, growth, and survival. To properly correct for sampling biases caused by gear and other sources, length-frequency distributions need to be corrected for imperfect detection. We describe a method for adjusting length-frequency distributions when capture and recapture probabilities are a function of fish length, temporal variation, and capture history. The method is applied to a study involving the removal of Smallmouth Bass Micropterus dolomieu by boat electrofishing from a 38.6-km reach on the Yampa River, Colorado. Smallmouth Bass longer than 100 mm were marked and released alive from 2005 to 2010 on one or more electrofishing passes and removed on all other passes from the population. Using the Huggins mark–recapture model, we detected a significant effect of fish total length, previous capture history (behavior), year, pass, year×behavior, and year×pass on capture and recapture probabilities. We demonstrate how to partition the Huggins estimate of abundance into length frequencies to correct for these effects. Uncorrected length frequencies of fish removed from Little Yampa Canyon were negatively biased in every year by as much as 88% relative to mark–recapture estimates for the smallest length-class in our analysis (100–110 mm). Bias declined but remained high even for adult length-classes (≥200 mm). The pattern of bias across length-classes was variable across years. The percentage of unadjusted counts that were below the lower 95% confidence interval from our adjusted length-frequency estimates were 95, 89, 84, 78, 81, and 92% from 2005 to 2010, respectively. Length-frequency distributions are widely used in fisheries science and management. Our simple method for correcting length-frequency estimates for imperfect detection could be widely applied when mark–recapture data

  13. A Novel Frequency Communication Technology in Power Distribution Communication Network

    Directory of Open Access Journals (Sweden)

    Li Ying-Jun

    2017-01-01

    Full Text Available With the expansion of the power terminal access network scale, the main road corridor resources, branch line cable Laying difficulties has become an important factor restricting the construction of the network. In this paper, we focus on the frequency communication technology in power distribution communication network, and design a novel technology in communication mode, error correcting coding and data transfer frame format. We also discuss the influence of voltage phase difference on power frequency communication. Meanwhile, we present the application scenario Electricity information collection, electricity remote control and other power business in smart grid with the novel frequency communication technology.

  14. Optimizing Power–Frequency Droop Characteristics of Distributed Energy Resources

    Energy Technology Data Exchange (ETDEWEB)

    Guggilam, Swaroop S.; Zhao, Changhong; Dall Anese, Emiliano; Chen, Yu Christine; Dhople, Sairaj V.

    2018-05-01

    This paper outlines a procedure to design power-frequency droop slopes for distributed energy resources (DERs) installed in distribution networks to optimally participate in primary frequency response. In particular, the droop slopes are engineered such that DERs respond in proportion to their power ratings and they are not unfairly penalized in power provisioning based on their location in the distribution network. The main contribution of our approach is that a guaranteed level of frequency regulation can be guaranteed at the feeder head, while ensuring that the outputs of individual DERs conform to some well-defined notion of fairness. The approach we adopt leverages an optimization-based perspective and suitable linearizations of the power-flow equations to embed notions of fairness and information regarding the physics of the power flows within the distribution network into the droop slopes. Time-domain simulations from a differential algebraic equation model of the 39-bus New England test-case system augmented with three instances of the IEEE 37-node distribution-network with frequency-sensitive DERs are provided to validate our approach.

  15. 75 FR 16513 - B&C Corporation, JR Engineering Division, Including B&C Distribution Center, Including On-Site...

    Science.gov (United States)

    2010-04-01

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-70, 975A] B&C Corporation, JR Engineering Division, Including B&C Distribution Center, Including On-Site Leased Workers From B&C Services... October 2, 2009, applicable to workers of B&C Corporation, JR Engineering Division, including on-site...

  16. Incoherent Optical Frequency Domain Reflectometry for Distributed Thermal Sensing

    DEFF Research Database (Denmark)

    Karamehmedovic, Emir

    2006-01-01

    This thesis reports the main results from an investigation of a fibre-optic distributed temperature sensor based on spontaneous Raman scattering. The technique used for spatial resolving is the incoherent optical frequency domain reflectometry, where a pump laser is sine modulated with a stepwise...

  17. Distribution and frequency of phenylthiocarbamide (PTC) taster and ...

    African Journals Online (AJOL)

    There is limited information on population genetics of the Nigerian population as regards taste perception. This study investigated the distribution and frequency of taster (T) and non-taster (t) alleles in the Nigerian population using phenylthiocarbamide [(PTC), % composition = 30 mcg/strip] taste strips. Overall, a total of ...

  18. The frequency-independent control method for distributed generation systems

    DEFF Research Database (Denmark)

    Naderi, Siamak; Pouresmaeil, Edris; Gao, Wenzhong David

    2012-01-01

    In this paper a novel frequency-independent control method suitable for distributed generation (DG) is presented. This strategy is derived based on the . abc/. αβ transformation and . abc/. dq transformation of the ac system variables. The active and reactive currents injected by the DG...

  19. Length Frequency Distribution And Sex Ratio Of Macrobrachium ...

    African Journals Online (AJOL)

    Length frequency distribution and sex ratio of Macrobrachium macrobrachion sampled by cane traps in the Lagos –Lekki lagoon system were estimated from May 2002 to April 2004. The total number of size classes for the first and second year for both male and female ranged from 10 – 12. The length range was 3 to 14cm ...

  20. The Incidence and Topographic Distribution of Sutures Including Wormian Bones in Human Skulls.

    Science.gov (United States)

    Cirpan, Sibel; Aksu, Funda; Mas, Nuket

    2015-07-01

    The Wormian Bones are accessory bones located within the cranial sutures and fontanelles. The present article examines the incidence of Wormian Bones and compares the number and topographic distribution between the sutures including Wormian Bones in skulls of West Anatolian Population. One hundred fifty crania were examined. The parameters evaluated in the present study were as follows: the rate of skulls including Wormian Bones; the topographic distribution and frequencies of the sutures including Wormian Bones; the number of these sutures for each skull; the name and number of sutures that were bilaterally and symmetrically located on the right and left side of skull (paired sutures) and which coincidentally had Wormian Bones for each skull; the differences of frequencies between the paired sutures including Wormian Bones. The rate of skulls including Wormian Bones was determined as 59.3%. The maximum and minimum numbers of sutures, including Wormian Bones, were 6 in 1 skull and 1 in each of 30 skulls, respectively. The maximum and minimum rates of sutures that had Wormian Bones were found in left lambdoid 40.7% and right occipitomastoid 1.3% sutures, respectively. There was only a significant difference between the rate of right and left squamous sutures (P = 0.04). Forty-five skulls were including 55 pairs of bilaterally and symmetrically located sutures that coincidentally had Wormian Bones in each pair. Each of 35 skulls had 1 pair of sutures including Wormian Bones and each of 10 skulls had 2 pairs. In the present study, the rate of Wormian Bones was determined as 59.3% in West Anatolian Population. This incidence rate is considerably lower than the other reports, and it may be as a result of racial variations. These divergent bones were more frequently found in left lambdoid sutures (40.7%) and less frequently in right occipitomastoid sutures (1.3%). This study may guide the investigators dealing with the neurosurgery, orthopedy, radiology, anatomy, and

  1. Influences on flood frequency distributions in Irish river catchments

    Directory of Open Access Journals (Sweden)

    S. Ahilan

    2012-04-01

    Full Text Available This study explores influences on flood frequency distributions in Irish rivers. A Generalised Extreme Value (GEV type I distribution is recommended in Ireland for estimating flood quantiles in a single site flood frequency analysis. This paper presents the findings of an investigation that identified the GEV statistical distributions that best fit the annual maximum (AM data series extracted from 172 gauging stations of 126 rivers in Ireland. Analysis of these data was undertaken to explore hydraulic and hydro-geological factors that influence flood frequency distributions. A hierarchical approach of increasing statistical power that used probability plots, moment and L-moment diagrams, the Hosking goodness of fit algorithm and a modified Anderson-Darling (A-D statistical test was followed to determine whether a type I, type II or type III distribution was valid. Results of the Hosking et al. method indicated that of the 143 stations with flow records exceeding 25 yr, data for 95 (67% was best represented by GEV type I distributions and a further 9 (6% and 39 (27% stations followed type II and type III distributions respectively. Type I, type II and type III distributions were determined for 83 (58%, 16 (11% and 34 (24% stations respectively using the modified A-D method (data from 10 stations was not represented by GEV family distributions. The influence of karst terrain on these flood frequency distributions was assessed by incorporating results on an Arc-GIS platform showing karst features and using Monte Carlo simulations to assess the significance of the number and clustering of the observed distributions. Floodplain effects were identified by using two-sample t-tests to identify statistical correlations between the distributions and catchment properties that are indicative of strong floodplain activity. The data reveals that type I distributions are spatially well represented throughout the country. While also well represented throughout

  2. Derived flood frequency distributions considering individual event hydrograph shapes

    Science.gov (United States)

    Hassini, Sonia; Guo, Yiping

    2017-04-01

    Derived in this paper is the frequency distribution of the peak discharge rate of a random runoff event from a small urban catchment. The derivation follows the derived probability distribution procedure and incorporates a catchment rainfall-runoff model with approximating shapes for individual runoff event hydrographs. In the past, only simple triangular runoff event hydrograph shapes were used, in this study approximating runoff event hydrograph shapes better representing all the possibilities are considered. The resulting closed-form mathematical equations are converted to the commonly required flood frequency distributions for use in urban stormwater management studies. The analytically determined peak discharge rates of different return periods for a wide range of hypothetical catchment conditions were compared to those determined from design storm modeling. The newly derived equations generated results that are closer to those from design storm modeling and provide a better alternative for use in urban stormwater management studies.

  3. Some consequences of including low frequencies in the evaluation of floor impact sound

    DEFF Research Database (Denmark)

    Rindel, Jens Holger; Rasmussen, Birgit

    1996-01-01

    A method for including frequencies down to 50 Hz in the evaluation of floor impact sound has become available with the new version of ISO 717-2. In addition to the single number quantity for rating the impact sound insulation, a new spectrum adaptation term has been defined. The method has been...... studied by the Acoustics Group of the Nordic Committee on Building Regulations. The new method has been applied to a large number of recent measuring results from the Nordic countries. It was found that the spectrum adaptation term for the extended frequency range depends on the type of floor construction...

  4. Cross-Language Distributions of High Frequency and Phonetically Similar Cognates

    Science.gov (United States)

    Schepens, Job; Dijkstra, Ton; Grootjen, Franc; van Heuven, Walter J. B.

    2013-01-01

    The coinciding form and meaning similarity of cognates, e.g. ‘flamme’ (French), ‘Flamme’ (German), ‘vlam’ (Dutch), meaning ‘flame’ in English, facilitates learning of additional languages. The cross-language frequency and similarity distributions of cognates vary according to evolutionary change and language contact. We compare frequency and orthographic (O), phonetic (P), and semantic similarity of cognates, automatically identified in semi-complete lexicons of six widely spoken languages. Comparisons of P and O similarity reveal inconsistent mappings in language pairs with deep orthographies. The frequency distributions show that cognate frequency is reduced in less closely related language pairs as compared to more closely related languages (e.g., French-English vs. German-English). These frequency and similarity patterns may support a better understanding of cognate processing in natural and experimental settings. The automatically identified cognates are available in the supplementary materials, including the frequency and similarity measurements. PMID:23675449

  5. Frequency and distribution of Notch mutations in tumor cell lines

    International Nuclear Information System (INIS)

    Mutvei, Anders Peter; Fredlund, Erik; Lendahl, Urban

    2015-01-01

    Deregulated Notch signaling is linked to a variety of tumors and it is therefore important to learn more about the frequency and distribution of Notch mutations in a tumor context. In this report, we use data from the recently developed Cancer Cell Line Encyclopedia to assess the frequency and distribution of Notch mutations in a large panel of cancer cell lines in silico. Our results show that the mutation frequency of Notch receptor and ligand genes is at par with that for established oncogenes and higher than for a set of house-keeping genes. Mutations were found across all four Notch receptor genes, but with notable differences between protein domains, mutations were for example more prevalent in the regions encoding the LNR and PEST domains in the Notch intracellular domain. Furthermore, an in silico estimation of functional impact showed that deleterious mutations cluster to the ligand-binding and the intracellular domains of NOTCH1. For most cell line groups, the mutation frequency of Notch genes is higher than in associated primary tumors. Our results shed new light on the spectrum of Notch mutations after in vitro culturing of tumor cells. The higher mutation frequency in tumor cell lines indicates that Notch mutations are associated with a growth advantage in vitro, and thus may be considered to be driver mutations in a tumor cell line context. The online version of this article (doi:10.1186/s12885-015-1278-x) contains supplementary material, which is available to authorized users

  6. Simple method of generating and distributing frequency-entangled qudits

    Science.gov (United States)

    Jin, Rui-Bo; Shimizu, Ryosuke; Fujiwara, Mikio; Takeoka, Masahiro; Wakabayashi, Ryota; Yamashita, Taro; Miki, Shigehito; Terai, Hirotaka; Gerrits, Thomas; Sasaki, Masahide

    2016-11-01

    High-dimensional, frequency-entangled photonic quantum bits (qudits for d-dimension) are promising resources for quantum information processing in an optical fiber network and can also be used to improve channel capacity and security for quantum communication. However, up to now, it is still challenging to prepare high-dimensional frequency-entangled qudits in experiments, due to technical limitations. Here we propose and experimentally implement a novel method for a simple generation of frequency-entangled qudts with d\\gt 10 without the use of any spectral filters or cavities. The generated state is distributed over 15 km in total length. This scheme combines the technique of spectral engineering of biphotons generated by spontaneous parametric down-conversion and the technique of spectrally resolved Hong-Ou-Mandel interference. Our frequency-entangled qudits will enable quantum cryptographic experiments with enhanced performances. This distribution of distinct entangled frequency modes may also be useful for improved metrology, quantum remote synchronization, as well as for fundamental test of stronger violation of local realism.

  7. Distributed Control of Nonlinear Aircraft Structures Including Aerodynamic and Temperature Interactions

    National Research Council Canada - National Science Library

    Tzou, H

    2004-01-01

    .... Distributed sensing/actuation, thermoelectromechanical/control equations and boundary conditions including elastic, temperature, and piezoelectric couplings are derived and applied to distributed...

  8. Performance Comparison of Time-Frequency Distributions for Estimation of Instantaneous Frequency of Heart Rate Variability Signals

    Directory of Open Access Journals (Sweden)

    Nabeel Ali Khan

    2017-02-01

    Full Text Available The instantaneous frequency (IF of a non-stationary signal is usually estimated from a time-frequency distribution (TFD. The IF of heart rate variability (HRV is an important parameter because the power in a frequency band around the IF can be used for the interpretation and analysis of the respiratory rate but also for a more accurate analysis of heart rate (HR signals. In this study, we compare the performance of five states of the art kernel-based time-frequency distributions (TFDs in terms of their ability to accurately estimate the IF of HR signals. The selected TFDs include three widely used fixed kernel methods: the modified B distribution, the S-method and the spectrogram; and two adaptive kernel methods: the adaptive optimal kernel TFD and the recently developed adaptive directional TFD. The IF of the respiratory signal, which is usually easier to estimate as the respiratory signal is a mono-component with small amplitude variations with time, is used as a reference to examine the accuracy of the HRV IF estimates. Experimental results indicate that the most reliable estimates are obtained using the adaptive directional TFD in comparison to other commonly used methods such as the adaptive optimal kernel TFD and the modified B distribution.

  9. Frequency distribution function of stellar flares in the Orion association

    International Nuclear Information System (INIS)

    Parsamian, E.S.

    1981-01-01

    The temporal distributions of flare stars in the Orion association and the numbers of stars with different flare frequencies are determined by means of Ambartsumian's (1978) method, which uses the chronology of discovery of 'first' flares and the chronology of confirmations, i.e., the temporal distributions of 'repeated' flares. It is shown that flare stars with high flare frequency (not greater than 1000 hours) in the Pleiades are basically stars of low luminosity with M(U) not less than 13m. Two independent methods of determining the number of flare stars in the aggregates confirm that there are about 1.5 times more flare stars in the Orion association than in the Pleiades

  10. Frequency distributions: from the sun to the earth

    Directory of Open Access Journals (Sweden)

    N. B. Crosby

    2011-11-01

    Full Text Available The space environment is forever changing on all spatial and temporal scales. Energy releases are observed in numerous dynamic phenomena (e.g. solar flares, coronal mass ejections, solar energetic particle events where measurements provide signatures of the dynamics. Parameters (e.g. peak count rate, total energy released, etc. describing these phenomena are found to have frequency size distributions that follow power-law behavior. Natural phenomena on Earth, such as earthquakes and landslides, display similar power-law behavior. This suggests an underlying universality in nature and poses the question of whether the distribution of energy is the same for all these phenomena. Frequency distributions provide constraints for models that aim to simulate the physics and statistics observed in the individual phenomenon. The concept of self-organized criticality (SOC, also known as the "avalanche concept", was introduced by Bak et al. (1987, 1988, to characterize the behavior of dissipative systems that contain a large number of elements interacting over a short range. The systems evolve to a critical state in which a minor event starts a chain reaction that can affect any number of elements in the system. It is found that frequency distributions of the output parameters from the chain reaction taken over a period of time can be represented by power-laws. During the last decades SOC has been debated from all angles. New SOC models, as well as non-SOC models have been proposed to explain the power-law behavior that is observed. Furthermore, since Bak's pioneering work in 1987, people have searched for signatures of SOC everywhere. This paper will review how SOC behavior has become one way of interpreting the power-law behavior observed in natural occurring phenomenon in the Sun down to the Earth.

  11. Frequency distributions in population genetics parallel those in statistical physics

    Science.gov (United States)

    Higgs, Paul G.

    1995-01-01

    A class of problems from statistical physics is discussed that is shown to be identical to a class of problems in population genetics. The mathematical treatment of these problems has arisen independently in the two subjects. The important results of both literatures are presented here, together with cross references. In each case there is a stochastic process generating a set of variables xi that satisfy tsumixi=1. For example, the xi may represent the weights of valleys in a spin glass, the sizes of attractors in dynamical systems, the frequency of different alleles in a population, or the sizes of different families in a genealogical tree. The frequency distributions f(x) of the valleys or alleles are calculated, together with the distribution Π(Y) of the quantity Y=tsumix2i. The distribution Π(Y) can be written as a sum of universal functions Πk(Y) that are independent of the parameters of the problem. It is shown that the rather abstract concepts in the physical models are directly related to observables that are experimentally measurable in biology.

  12. Distributive estimation of frequency selective channels for massive MIMO systems

    KAUST Repository

    Zaib, Alam

    2015-12-28

    We consider frequency selective channel estimation in the uplink of massive MIMO-OFDM systems, where our major concern is complexity. A low complexity distributed LMMSE algorithm is proposed that attains near optimal channel impulse response (CIR) estimates from noisy observations at receive antenna array. In proposed method, every antenna estimates the CIRs of its neighborhood followed by recursive sharing of estimates with immediate neighbors. At each step, every antenna calculates the weighted average of shared estimates which converges to near optimal LMMSE solution. The simulation results validate the near optimal performance of proposed algorithm in terms of mean square error (MSE). © 2015 EURASIP.

  13. Killer whale (Orcinus orca) whistles from the western South Atlantic Ocean include high frequency signals.

    Science.gov (United States)

    Andriolo, Artur; Reis, Sarah S; Amorim, Thiago O S; Sucunza, Federico; de Castro, Franciele R; Maia, Ygor Geyer; Zerbini, Alexandre N; Bortolotto, Guilherme A; Dalla Rosa, Luciano

    2015-09-01

    Acoustic parameters of killer whale (Orcinus orca) whistles were described for the western South Atlantic Ocean and highlight the occurrence of high frequency whistles. Killer whale signals were recorded on December of 2012, when a pod of four individuals was observed harassing a group of sperm whales. The high frequency whistles were highly stereotyped and were modulated mostly at ultrasonic frequencies. Compared to other contour types, the high frequency whistles are characterized by higher bandwidths, shorter durations, fewer harmonics, and higher sweep rates. The results add to the knowledge of vocal behavior of this species.

  14. A frequency domain linearized Navier-Stokes method including acoustic damping by eddy viscosity using RANS

    Science.gov (United States)

    Holmberg, Andreas; Kierkegaard, Axel; Weng, Chenyang

    2015-06-01

    In this paper, a method for including damping of acoustic energy in regions of strong turbulence is derived for a linearized Navier-Stokes method in the frequency domain. The proposed method is validated and analyzed in 2D only, although the formulation is fully presented in 3D. The result is applied in a study of the linear interaction between the acoustic and the hydrodynamic field in a 2D T-junction, subject to grazing flow at Mach 0.1. Part of the acoustic energy at the upstream edge of the junction is shed as harmonically oscillating disturbances, which are conveyed across the shear layer over the junction, where they interact with the acoustic field. As the acoustic waves travel in regions of strong shear, there is a need to include the interaction between the background turbulence and the acoustic field. For this purpose, the oscillation of the background turbulence Reynold's stress, due to the acoustic field, is modeled using an eddy Newtonian model assumption. The time averaged flow is first solved for using RANS along with a k-ε turbulence model. The spatially varying turbulent eddy viscosity is then added to the spatially invariant kinematic viscosity in the acoustic set of equations. The response of the 2D T-junction to an incident acoustic field is analyzed via a plane wave scattering matrix model, and the result is compared to experimental data for a T-junction of rectangular ducts. A strong improvement in the agreement between calculation and experimental data is found when the modification proposed in this paper is implemented. Discrepancies remaining are likely due to inaccuracies in the selected turbulence model, which is known to produce large errors e.g. for flows with significant rotation, which the grazing flow across the T-junction certainly is. A natural next step is therefore to test the proposed methodology together with more sophisticated turbulence models.

  15. Landslide scaling and magnitude-frequency distribution (Invited)

    Science.gov (United States)

    Stark, C. P.; Guzzetti, F.

    2009-12-01

    Landslide-driven erosion is controlled by the scale and frequency of slope failures and by the consequent fluxes of debris off the hillslopes. Here I focus on the magnitude-frequency part of the process and develop a theory of initial slope failure and debris mobilization that reproduces the heavy-tailed distributions (PDFs) observed for landslide source areas and volumes. Landslide rupture propagation is treated as a quasi-static, non-inertial process of simplified elastoplastic deformation with strain weakening; debris runout is not considered. The model tracks the stochastically evolving imbalance of frictional, cohesive, and body forces across a failing slope, and uses safety-factor concepts to convert the evolving imbalance into a series of incremental rupture growth or arrest probabilities. A single rupture is simulated with a sequence of weighted ``coin tosses'' with weights set by the growth probabilities. Slope failure treated in this stochastic way is a survival process that generates asymptotically power-law-tail PDFs of area and volume for rock and debris slides; predicted scaling exponents are consistent with analyses of landslide inventories. The primary control on the shape of the model PDFs is the relative importance of cohesion over friction in setting slope stability: the scaling of smaller, shallower failures, and the size of the most common landslide volumes, are the result of the low cohesion of soil and regolith, whereas the negative power-law tail scaling for larger failures is tied to the greater cohesion of bedrock. The debris budget may be dominated by small or large landslides depending on the scaling of both the PDF and of the depth-length relation. I will present new model results that confirm the hypothesis that depth-length scaling is linear. Model PDF of landslide volumes.

  16. High-speed ac motor including the function of a magnetic frequency tripler

    OpenAIRE

    Yamada, Sotoshi; Takeuchi, A.; Sudani, T.; Bessho, Kazuo

    1986-01-01

    The new electric motor is the magnetic combination of a magnetic frequency multiplier and a AC motor which share the common magnetic yoke. The motor operates near the synchronous speed (10,800 rpm) by applied the single-phase commercial source at 60 Hz. The new machine is called “high-speed hybrid AC motor” because the combination of a motor and a frequency converter. This paper describes the structure and the operating characteristics of the new motor.

  17. Under-Frequency Load Shedding Technique Considering Event-Based for an Islanded Distribution Network

    Directory of Open Access Journals (Sweden)

    Hasmaini Mohamad

    2016-06-01

    Full Text Available One of the biggest challenge for an islanding operation is to sustain the frequency stability. A large power imbalance following islanding would cause under-frequency, hence an appropriate control is required to shed certain amount of load. The main objective of this research is to develop an adaptive under-frequency load shedding (UFLS technique for an islanding system. The technique is designed considering an event-based which includes the moment system is islanded and a tripping of any DG unit during islanding operation. A disturbance magnitude is calculated to determine the amount of load to be shed. The technique is modeled by using PSCAD simulation tool. A simulation studies on a distribution network with mini hydro generation is carried out to evaluate the UFLS model. It is performed under different load condition: peak and base load. Results show that the load shedding technique have successfully shed certain amount of load and stabilized the system frequency.

  18. Electromagnetic field nonuniformities in large area, high-frequency capacitive plasma reactors, including electrode asymmetry effects

    International Nuclear Information System (INIS)

    Sansonnens, L; Howling, A A; Hollenstein, Ch

    2006-01-01

    Electromagnetic wave propagation effects can give rise to important limitations for processing uniformity in large area, radio-frequency (rf) capacitive plasma reactors. The electromagnetic wavefield solution is derived for a capacitive, high-frequency, cylindrical reactor with symmetric or asymmetric electrode areas containing a uniform plasma slab. It is shown that only two distinct electromagnetic modes are necessary and sufficient to determine the electromagnetic fields everywhere within the reactor except close to the sidewalls. The first mode gives rise to the interelectrode rf voltage standing wave effect associated with high frequencies in large area reactors, and the second mode gives rise to the telegraph effect associated with asymmetric electrode areas, which necessitates the redistribution of rf current along the plasma to maintain rf current continuity. This work gives a unified treatment of both effects which have previously been studied separately, experimentally and theoretically, in the literature. The equivalent circuit of each mode is also derived from its respective dispersion relation. Examples of this electromagnetic wavefield solution show that both modes can cause nonuniformity of the plasma rf potential, depending on the reactor geometry, excitation frequency and plasma permittivity and sheath width, which has consequences for large-area plasma processing

  19. Impact of protection settings of the distributed generation frequency under 1MW in the national electric system

    International Nuclear Information System (INIS)

    Alpizar Chavarria, Oscar

    2013-01-01

    A literature review is conducted to understand the distributed generation, the reason for the introduction into modern power systems and other distributed generation technologies based on renewable energies that have been installed around the country. The frequency protections of distributed generation equipment under 1MW are studied according to international standards like IEEE-1547 and specifications of equipment manufacturers. The influence of the recommended international standards settings are investigated for systems of distributed generation, the performance in frequency that have presented under some frequency perturbation, as well as the influence that can have on the national and regional electrical system, with different amounts of technologies included in the national system. The recommended settings are evaluated through simulations in PSSE program in the context of the behavior of the frequency in the national electric system [es

  20. Dynamic Response to Pedestrian Loads with Statistical Frequency Distribution

    DEFF Research Database (Denmark)

    Krenk, Steen

    2012-01-01

    on the magnitude of the resulting response. A frequency representation of vertical pedestrian load is developed, and a compact explicit formula is developed for the magnitude of the resulting response, in terms of the damping ratio of the structure, the bandwidth of the pedestrian load, and the mean footfall...... frequency. The accuracy of the formula is verified by a statistical moment analysis using the Lyapunov equations....

  1. Allozyme frequency distribution patterns at two gene loci of the ...

    African Journals Online (AJOL)

    Allele frequencies for PGM1*-1, PGM2*-1 and FH1*-1 were highest in the deciduous forest zone. The alleles PGM1*-2, PGM2*-2 and FH1*-2 were highest in the Guinea savanna zone, while the highest frequencies for alleles PGM1*-3, PGM2*-3, PGM2*-4 and FH1*-3 occurred in the Sudan savanna zone. Alleles PGM2*-3 ...

  2. Distributed Secondary Voltage and Frequency Control for Islanded Microgrids with Uncertain Communication Links

    DEFF Research Database (Denmark)

    Lu, Xiaoqing; Yu, Xinghuo; Lai, Jingang

    2017-01-01

    intermittently in a low-bandwidth communication manner. This way, the communication costs are greatly reduced, and some sufficient conditions on the system stability and robustness to the uncertainties are also derived by using the tools of Lyapunov stability theory, algebraic graph theory, and matrix inequality......This paper presents a robust distributed secondary control (DSC) scheme for inverter-based microgrids (MGs) in a distribution sparse network with uncertain communication links. By using the iterative learning mechanics, two discrete-time DSC controllers are designed, which enable all distributed...... theory. The proposed controllers are implemented on local DERs, and thus no central controller is required. Moreover, the desired control objective can also be guaranteed even if all DERs are subject to internal uncertainties and external noises including initial voltage and/or frequency resetting errors...

  3. Benefits of time-frequency coding for quantum key distribution

    Science.gov (United States)

    Rödiger, J.; Perlot, N.; Benson, O.; Freund, R.

    2017-09-01

    Quantum key distribution (QKD), the first applicable quantum technology, is able to distribute a secret key to two parties. This key can then be used as a one-time-pad for absolutely secure communication. The first QKD protocol was the polarization based BB84 protocol proposed in [1]. Since then many QKD protocols have been proposed and investigated [2, 3].

  4. Statistical Tests for Frequency Distribution of Mean Gravity Anomalies

    African Journals Online (AJOL)

    The hypothesis that a very large number of lOx 10mean gravity anomalies are normally distributed has been rejected at 5% Significance level based on the X2 and the unit normal deviate tests. However, the 50 equal area mean anomalies derived from the lOx 10data, have been found to be normally distributed at the same ...

  5. Frequency participation by using virtual inertia in wind turbines including energy storage

    DEFF Research Database (Denmark)

    Xiao, Zhao xia; Huang, Yu; Guerrero, Josep M.

    2017-01-01

    (WT) and battery unit (BU). A central controller forecasts wind speed and determines system operation states to be sent to the local controllers. These local controllers include MPPT, virtual inertia, and pitch control for the WT; and power control loops for the BU. The proposed approach achieve...

  6. Microwave frequency electromagnetic fields (EMFs) produce widespread neuropsychiatric effects including depression.

    Science.gov (United States)

    Pall, Martin L

    2016-09-01

    Non-thermal microwave/lower frequency electromagnetic fields (EMFs) act via voltage-gated calcium channel (VGCC) activation. Calcium channel blockers block EMF effects and several types of additional evidence confirm this mechanism. Low intensity microwave EMFs have been proposed to produce neuropsychiatric effects, sometimes called microwave syndrome, and the focus of this review is whether these are indeed well documented and consistent with the known mechanism(s) of action of such EMFs. VGCCs occur in very high densities throughout the nervous system and have near universal roles in release of neurotransmitters and neuroendocrine hormones. Soviet and Western literature shows that much of the impact of non-thermal microwave exposures in experimental animals occurs in the brain and peripheral nervous system, such that nervous system histology and function show diverse and substantial changes. These may be generated through roles of VGCC activation, producing excessive neurotransmitter/neuroendocrine release as well as oxidative/nitrosative stress and other responses. Excessive VGCC activity has been shown from genetic polymorphism studies to have roles in producing neuropsychiatric changes in humans. Two U.S. government reports from the 1970s to 1980s provide evidence for many neuropsychiatric effects of non-thermal microwave EMFs, based on occupational exposure studies. 18 more recent epidemiological studies, provide substantial evidence that microwave EMFs from cell/mobile phone base stations, excessive cell/mobile phone usage and from wireless smart meters can each produce similar patterns of neuropsychiatric effects, with several of these studies showing clear dose-response relationships. Lesser evidence from 6 additional studies suggests that short wave, radio station, occupational and digital TV antenna exposures may produce similar neuropsychiatric effects. Among the more commonly reported changes are sleep disturbance/insomnia, headache, depression

  7. Entropy-based derivation of generalized distributions for hydrometeorological frequency analysis

    Science.gov (United States)

    Chen, Lu; Singh, Vijay P.

    2018-02-01

    Frequency analysis of hydrometeorological and hydrological extremes is needed for the design of hydraulic and civil infrastructure facilities as well as water resources management. A multitude of distributions have been employed for frequency analysis of these extremes. However, no single distribution has been accepted as a global standard. Employing the entropy theory, this study derived five generalized distributions for frequency analysis that used different kinds of information encoded as constraints. These distributions were the generalized gamma (GG), the generalized beta distribution of the second kind (GB2), and the Halphen type A distribution (Hal-A), Halphen type B distribution (Hal-B) and Halphen type inverse B distribution (Hal-IB), among which the GG and GB2 distribution were previously derived by Papalexiou and Koutsoyiannis (2012) and the Halphen family was first derived using entropy theory in this paper. The entropy theory allowed to estimate parameters of the distributions in terms of the constraints used for their derivation. The distributions were tested using extreme daily and hourly rainfall data. Results show that the root mean square error (RMSE) values were very small, which indicated that the five generalized distributions fitted the extreme rainfall data well. Among them, according to the Akaike information criterion (AIC) values, generally the GB2 and Halphen family gave a better fit. Therefore, those general distributions are one of the best choices for frequency analysis. The entropy-based derivation led to a new way for frequency analysis of hydrometeorological extremes.

  8. Frequency distribution 0f ABO, RH blood groups and blood ...

    African Journals Online (AJOL)

    One hundred and fifty students (150) were randomly selected from the Department of Cell Biology and Genetics of University of Lagos, Akoka, Nigeria for ABO, RH blood groups and 6 haemoglobin genotypes studies. Blood group O was the highest with the percentage frequency of 55.3%, followed by blood group A (25.3%) ...

  9. Tuningless Load Frequency Control Through Active Engagement of Distributed Resources

    DEFF Research Database (Denmark)

    Prostejovsky, Alexander; Marinelli, Mattia; Rezkalla, Michel M.N.

    2017-01-01

    The increasing share of volatile and inverter-based energy sources render electric power grids increasingly susceptible to disturbances. Established Load Frequency Control (LFC) schemes are rigid and require careful tuning, making them unsuitable for dynamically changing environments. In this paper...

  10. ABO and Rh (D group distribution and gene frequency; the first multicentric study in India

    Directory of Open Access Journals (Sweden)

    Amit Agrawal

    2014-01-01

    Full Text Available Background and Objectives: The study was undertaken with the objective to provide data on the ABO and Rh(D blood group distribution and gene frequency across India. Materials and Methods: A total of 10,000 healthy blood donors donating in blood banks situated in five different geographical regions of the country (North, South, East and Center were included in the study. ABO and Rh (D grouping was performed on all these samples. Data on the frequency of ABO and Rh(D blood groups was reported in simple numbers and percentages. Results: The study showed that O was the most common blood group (37.12% in the country closely followed by B at 32.26%, followed by A at 22.88% while AB was the least prevalent group at 7.74%. 94.61% of the donor population was Rh positive and the rest were Rh negative. Regional variations were observed in the distribution. Using the maximum likelihood method, the frequencies of the I A , I B and I O alleles were calculated and tested according to the Hardy Weinberg law of Equilibrium. The calculated gene frequencies are 0.1653 for I A (p, 0.2254 for I B (q and 0.6093 for I O (r. In Indian Population, O (r records the highest value followed by B (q and A (p; O > B > A. Conclusion: The study provides information about the relative distribution of various alleles in the Indian population both on a pan-India basis as well as region-wise. This vital information may be helpful in planning for future health challenges, particularly planning with regards to blood transfusion services.

  11. Cystic fibrosis in Jews: frequency and mutation distribution.

    Science.gov (United States)

    Kerem, B; Chiba-Falek, O; Kerem, E

    1997-01-01

    The incidence of cystic fibrosis and the frequency of disease causing mutations varies among different ethnic groups and geographical regions around the world. The Jewish population is comprised of two major ethnic groups. Ashkenazi and Non-Ashkenazi. The latter is further classified according to country of origin. An extreme variability in the disease frequency (from 1:2400-1:39,000) was found among the different Jewish ethnic groups. In the entire Jewish CF population, only 12 mutations were identified that altogether enable the identification of 91% of the CF chromosomes. However, in each Jewish ethnic group, the disease is caused by a different repertoire of a small number of mutations. In several ethnic groups, there is a major CFTR mutation that accounts for at least 48% of the CF chromosomes. High proportion of the CF chromosomes can be identified in Ashkenazi Jews (95%), Jews originating from Tunisia (100%), Libya (91%), Turkey (90%), and Georgia (88%). High frequencies of CFTR mutations were found among infertile males with CBAVD who might not have additional CF clinical characteristics. Of the Jewish males with CBAVD, 77% carried at least one CFTR mutation. The 5T mutation is the major mutation in Jewish CBAVD affecteds accounting for 32% of the chromosomes among Ashkenazi Jews and 36% among the non-Ashkenazi Jews. Five additional CFTR mutations, W1282X (12%), delta F508 (9%), N1303K (3%), D1152H, (5%)), and R117H (1%) were identified among Ashkenazi Jews with CBAVD. Only two mutations, delta F508 and R117H, were found among non-Ashkenazi males with CBAVD. An increased frequency of the 5T allele was also found among Jewish patients with atypical CF presentation, 18% in Ashkenazi, and 10% in non-Ashkenazi Jews. In summary, we present the required information for genetic counseling of Jewish families with typical and atypical CF and for carrier screening of healthy Jewish individuals.

  12. Frequency and distribution studies of asymmetrical versus symmetrical chromosome aberrations

    International Nuclear Information System (INIS)

    Savage, J.R.K.; Papworth, D.G.

    1982-01-01

    Two aspects of the relationship between Asymmetrical (A) and Symmetrical (S) radiation-induced chromosomal aberrations are considered in this paper. (1) Are A and S truly alternative modes of lesion interaction. Relative frequencies for chromatid-type and chromosome-type are examined, and new lymphocyte data using banding is used to look at this, and also for parallelism in chromosome participation of the two forms for various aberration categories. All the tests applied suggest that A and S are alternative interaction modes. (2) The long-term survival characteristics of A and S are discussed, and the differences in expected frequencies of derived S per surviving cell from chromosome-type and chromatid-types are stressed. Since many in vivo tissues have varying mixtures of potential chromatid and chromosome aberration-bearing target cells, ultimate cell survival and derived S frequencies may differ between tissues for the same absorbed dose. An Appendix gives Relative Corrected Lengths (RCL) for chromosomes of the human karyotype which should be used when testing the various exchange aberration categories for random chromosome participation. (orig.)

  13. Topology Optimization of Distributed Mass Dampers for Low-frequency Vibration Suppression

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard; Lazarov, Boyan Stefanov

    2007-01-01

    In this paper the method of topology optimization is used to find optimized parameter distributions for a multiple mass damper system with the purpose of minimizing the low-frequency steady-state response of a carrier structure. An effective density model that describes the steady-state effect...... of the dampers is derived based on a continuous approximation of the damper distribution. The dampers are optimized with respect to the point-wise distribution of mass ratio, natural frequency, and damping ratio....

  14. Randomized algorithms for tracking distributed count, frequencies, and ranks

    DEFF Research Database (Denmark)

    Zengfeng, Huang; Ke, Yi; Zhang, Qin

    2012-01-01

    We show that randomization can lead to significant improvements for a few fundamental problems in distributed tracking. Our basis is the count-tracking problem, where there are k players, each holding a counter ni that gets incremented over time, and the goal is to track an ∑-approximation of the...

  15. statistical tests for frequency distribution of mean gravity anomalies

    African Journals Online (AJOL)

    ES Obe

    1980-03-01

    Mar 1, 1980 ... ABSTRACT. The hypothesis that a very large number of lOx 10mean gravity anomalies are normally distributed has been rejected at 5%. Significance level based on the X2 and the unit normal deviate tests. However, the 50 equal area mean anomalies derived from the lOx 10data, have been found to be ...

  16. Comparative Study on the Selection Criteria for Fitting Flood Frequency Distribution Models with Emphasis on Upper-Tail Behavior

    Directory of Open Access Journals (Sweden)

    Xiaohong Chen

    2017-05-01

    Full Text Available The upper tail of a flood frequency distribution is always specifically concerned with flood control. However, different model selection criteria often give different optimal distributions when the focus is on the upper tail of distribution. With emphasis on the upper-tail behavior, five distribution selection criteria including two hypothesis tests and three information-based criteria are evaluated in selecting the best fitted distribution from eight widely used distributions by using datasets from Thames River, Wabash River, Beijiang River and Huai River. The performance of the five selection criteria is verified by using a composite criterion with focus on upper tail events. This paper demonstrated an approach for optimally selecting suitable flood frequency distributions. Results illustrate that (1 there are different selections of frequency distributions in the four rivers by using hypothesis tests and information-based criteria approaches. Hypothesis tests are more likely to choose complex, parametric models, and information-based criteria prefer to choose simple, effective models. Different selection criteria have no particular tendency toward the tail of the distribution; (2 The information-based criteria perform better than hypothesis tests in most cases when the focus is on the goodness of predictions of the extreme upper tail events. The distributions selected by information-based criteria are more likely to be close to true values than the distributions selected by hypothesis test methods in the upper tail of the frequency curve; (3 The proposed composite criterion not only can select the optimal distribution, but also can evaluate the error of estimated value, which often plays an important role in the risk assessment and engineering design. In order to decide on a particular distribution to fit the high flow, it would be better to use the composite criterion.

  17. Distribution of forensic marker allelic frequencies in Pernambuco, Northestern Brazil.

    Science.gov (United States)

    Santos, S M; Souza, C A; Rabelo, K C N; Souza, P R E; Moura, R R; Oliveira, T C; Crovella, S

    2015-04-30

    Pernambuco is one of the 27 federal units of Brazil, ranking seventh in the number of inhabitants. We examined the allele frequencies of 13 short tandem repeat loci (CFS1PO, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, FGA, TH01, vWA, and TPOX), the minimum recommended by the Federal Bureau of Investigation and commonly used in forensic genetics laboratories in Brazil, in a sample of 609 unrelated individuals from all geographic regions of Pernambuco. The allele frequencies ranged from 5 to 47.2%. No significant differences for any loci analyzed were observed compared with other publications in other various regions of Brazil. Most of the markers observed were in Hardy-Weinberg equilibrium. The occurrence of the allele 47.2 (locus FGA) and alleles 35.1 and 39 (locus D21S11), also described in a single study of the Brazilian population, was observed. The other forensic parameters analyzed (matching probability, power of discrimination, polymorphic information content, paternity exclusion, complement factor I, observed heterozygosity, expected heterozygosity) indicated that the studied markers are very informative for human forensic identification purposes in the Pernambuco population.

  18. High-Frequency ac Power-Distribution System

    Science.gov (United States)

    Hansen, Irving G.; Mildice, James

    1987-01-01

    Loads managed automatically under cycle-by-cycle control. 440-V rms, 20-kHz ac power system developed. System flexible, versatile, and "transparent" to user equipment, while maintaining high efficiency and low weight. Electrical source, from dc to 2,200-Hz ac converted to 440-V rms, 20-kHz, single-phase ac. Power distributed through low-inductance cables. Output power either dc or variable ac. Energy transferred per cycle reduced by factor of 50. Number of parts reduced by factor of about 5 and power loss reduced by two-thirds. Factors result in increased reliability and reduced costs. Used in any power-distribution system requiring high efficiency, high reliability, low weight, and flexibility to handle variety of sources and loads.

  19. HYPOCENTER DISTRIBUTION OF LOW FREQUENCY EVENT AT PAPANDAYAN VOLCANO

    Directory of Open Access Journals (Sweden)

    Muhammad Mifta Hasan

    2016-10-01

    Full Text Available Papandayan volcano is a stratovolcano with irregular cone-shaped has eight craters around the peak. The most active crater in Papandayan is a Mas crater. Distribution of relocated event calculated using Geiger Adaptive Damping Algorithm (GAD shows that the epicenter of the event centered below Mas crater with maximum rms 0.114. While depth of the hypocenter range between 0-2 km and 5-6 km due to activity of steam and gas.

  20. Distributed Optical Fiber Sensors Based on Optical Frequency Domain Reflectometry: A review.

    Science.gov (United States)

    Ding, Zhenyang; Wang, Chenhuan; Liu, Kun; Jiang, Junfeng; Yang, Di; Pan, Guanyi; Pu, Zelin; Liu, Tiegen

    2018-04-03

    Distributed optical fiber sensors (DOFS) offer unprecedented features, the most unique one of which is the ability of monitoring variations of the physical and chemical parameters with spatial continuity along the fiber. Among all these distributed sensing techniques, optical frequency domain reflectometry (OFDR) has been given tremendous attention because of its high spatial resolution and large dynamic range. In addition, DOFS based on OFDR have been used to sense many parameters. In this review, we will survey the key technologies for improving sensing range, spatial resolution and sensing performance in DOFS based on OFDR. We also introduce the sensing mechanisms and the applications of DOFS based on OFDR including strain, stress, vibration, temperature, 3D shape, flow, refractive index, magnetic field, radiation, gas and so on.

  1. The Watts-Strogatz network model developed by including degree distribution: theory and computer simulation

    International Nuclear Information System (INIS)

    Chen, Y W; Zhang, L F; Huang, J P

    2007-01-01

    By using theoretical analysis and computer simulations, we develop the Watts-Strogatz network model by including degree distribution, in an attempt to improve the comparison between characteristic path lengths and clustering coefficients predicted by the original Watts-Strogatz network model and those of the real networks with the small-world property. Good agreement between the predictions of the theoretical analysis and those of the computer simulations has been shown. It is found that the developed Watts-Strogatz network model can fit the real small-world networks more satisfactorily. Some other interesting results are also reported by adjusting the parameters in a model degree-distribution function. The developed Watts-Strogatz network model is expected to help in the future analysis of various social problems as well as financial markets with the small-world property

  2. Frequency distribution of foraminifera off Trivandrum, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Kutty, M.K.; Panikkar, B.M.

    abundant form is Ammonia beccarii (Linne) tepida and other species include Operculina ammonoides, Nonion asterizans and Hanzawaia concentrica. Comparison of the fauna of the Trivandrum area with that of Cochin Region, Kerala, India shows 14 common species...

  3. Damage Detection Based on Cross-Term Extraction from Bilinear Time-Frequency Distributions

    Directory of Open Access Journals (Sweden)

    Ma Yuchao

    2014-01-01

    Full Text Available Abundant damage information is implicated in the bilinear time-frequency distribution of structural dynamic signals, which could provide effective support for structural damage identification. Signal time-frequency analysis methods are reviewed, and the characters of linear time-frequency distribution and bilinear time-frequency distribution typically represented by the Wigner-Ville distribution are compared. The existence of the cross-term and its application in structural damage detection are demonstrated. A method of extracting the dominant term is proposed, which combines the short-time Fourier spectrum and Wigner-Ville distribution; then two-dimensional time-frequency transformation matrix is constructed and the complete cross-term is extracted finally. The distribution character of which could be applied to the structural damage identification. Through theoretical analysis, model experiment and numerical simulation of the girder structure, the change rate of cross-term amplitude is validated to identify the damage location and degree. The effectiveness of the cross-term of bilinear time-frequency distribution for damage detection is confirmed and the analytical method of damage identification used in structural engineering is available.

  4. Frequency distributions of helminths of wolves in Kazakhstan.

    Science.gov (United States)

    Abdybekova, A M; Torgerson, P R

    2012-03-23

    Between 2001 and 2008 a total of 41 wolves (Canis lupus) were necropsied in southern Kazakhstan and their intestinal parasite fauna evaluated. Of these animals 8 (19.5%) were infected with Echinococcus granulosus, 15 (36%) with Taenia spp, 13 (31.7%) with Dypilidium caninum, 5 (12.2%) with Mesocestoides lineatus, 15 (36.6%) with Toxocara canis, 16 (39%) with Toxascaris leonina, 8 (19.5%) with Trichuris vulpis, 9 (22%) with Macracanthorhynchus catulinus and 1 (2.4%) with Moniliformis moniliformis. All parasites had an aggregated distribution which followed a zero inflated or hurdle model. Although a small convenience sample of wolves, the results indicate a high prevalence of infection with E. granulosus. The mean abundance (1275 E. granulosus per wolf) was high with individual infected wolves carrying intensities of several thousand parasites. As wolves are common in Kazakhstan they may act as an important host in the transmission of this zoonotic parasite. The wolves were sampled from an area of Kazakhstan where there is a high prevalence of hydatid cysts in livestock and where echinococcosis has been observed in wild ungulates. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Distribution and frequency of wildfire in California riparian ecosystems

    Science.gov (United States)

    Bendix, Jacob; Commons, Michael G.

    2017-07-01

    Although wildfire has been recognized as having important ecological impacts on California’s riparian environments, understanding of its occurrence is largely anecdotal, based on studies of fire impacts in scattered locations. In this paper we use data for 21 years of wildfires to examine the distribution, seasonality and climatic context of riparian wildfire across the state. We used the Monitoring Trends in Burn Severity and LANDFIRE databases to identify fires that had burned in areas classified as having riparian vegetation, and matched those fires with the Fire and Resource Assessment Program database to determine the date of occurrence of each. From 1990 through 2010, an average of 1197 ha of riparian vegetation burned per year, which extrapolates to a fire return interval of 843 years. The statewide totals are misleading, however, because there is substantial geographic variance in the occurrence of riparian fire. In southern California ecoregions, extrapolated return intervals are as low as 74 years, contrasting with the Basin and Range ecoregions, where return intervals exceed 1000 years. Moreover, there is substantial geographic variation in the season of riparian fire, and in the relationship between fire occurrence and climatic variables. Both the widespread occurrence of riparian fire and its spatial variability are potentially important for management of critical riparian habitat.

  6. Repeatability of food frequency assessment tools in relation to the number of items and response categories included.

    Science.gov (United States)

    Bountziouka, Vassiliki; Bathrellou, Eirini; Zazpe, Itziar; Ezquer, Leyre; Martínez-González, Miguel-Angel; Panagiotakos, Demosthenes B

    2012-12-01

    Accuracy of measurement is a cornerstone of research in order to make robust conclusions about the research hypothesis. To examine whether the number of items (questions) and the number of consumption responses (the coding used to measure the frequency of consumption) included in nutritional assessment tools influence their repeatability. During 2009, 400 participants (250 from Greece, mean age 37 +/- 13 years, 34% males, and 150 from Spain, mean age 39 +/- 17 years, 41% males) completed a diet index with 11 items and binary (yes/ no) responses, a diet index with 11 items and 6-scale responses, and 36-item and 76-item food frequency questionnaires (FFQs) with 6-scale responses. The participants completed these tools twice, with 15 days between the two administrations of the tools. The Spearman-Brown coefficient (r(sb)), Kendall's tau coefficients, and the Bland-Altman method were applied to answer the research hypothesis. The highest repeatability coefficient was observed for the diet index with 11 items and binary (yes/no) responses (r(sb) = 0.948, p tools (p > .23), whereas these three tools had significantly higher repeatability coefficients than the 76-item FFQ (p = .002). Subgroup analyses by sex, education, smoking, and clinical status confirmed these results. Repeatability was found for all food frequency assessment tools used, irrespective of the number of items or the number of responses included.

  7. Distributed Optimization Design of Continuous-Time Multiagent Systems With Unknown-Frequency Disturbances.

    Science.gov (United States)

    Wang, Xinghu; Hong, Yiguang; Yi, Peng; Ji, Haibo; Kang, Yu

    2017-05-24

    In this paper, a distributed optimization problem is studied for continuous-time multiagent systems with unknown-frequency disturbances. A distributed gradient-based control is proposed for the agents to achieve the optimal consensus with estimating unknown frequencies and rejecting the bounded disturbance in the semi-global sense. Based on convex optimization analysis and adaptive internal model approach, the exact optimization solution can be obtained for the multiagent system disturbed by exogenous disturbances with uncertain parameters.

  8. Secondary Frequency and Voltage Control of Islanded Microgrids via Distributed Averaging

    DEFF Research Database (Denmark)

    W. Simpson-Porco, John; Shafiee, Qobad; Dorfler, Florian

    2015-01-01

    actions. The frequency controller rapidly regulates the microgrid frequency to its nominal value while maintaining active power sharing among the distributed generators. Tuning of the voltage controller provides a simple and intuitive trade-off between the conflicting goals of voltage regulation...

  9. Highly stable microwave carrier generation using a dual-frequency distributed feedback laser

    NARCIS (Netherlands)

    Khan, M.R.H.; Bernhardi, Edward; Marpaung, D.A.I.; Burla, M.; de Ridder, R.M.; Worhoff, Kerstin; Pollnau, Markus; Roeloffzen, C.G.H.

    2012-01-01

    Photonic generation of microwave carriers by using a dual-frequency distributed feedback waveguide laser in ytterbium-doped aluminum oxide is demonstrated. A highperformance optical frequency locked loop is implemented to stabilize the microwave carrier. This approach results in a microwave

  10. Daris, a low-frequency distributed aperture array for radio astronomy in space

    NARCIS (Netherlands)

    Boonstra, A.J.; Saks, N.; Bentum, Marinus Jan; van 't Klooster, K.; Falcke, H.

    2010-01-01

    DARIS (Distributed Aperture Array for Radio Astronomy in Space) is a radio astronomy space mission concept aimed at observing the low-frequency radio sky in the range 1-10 MHz. Because of the Earth's ionospheric disturbances and opaqueness, this frequency range can only be observed from space. The

  11. Optimal fuzzy logic-based PID controller for load-frequency control including superconducting magnetic energy storage units

    International Nuclear Information System (INIS)

    Pothiya, Saravuth; Ngamroo, Issarachai

    2008-01-01

    This paper proposes a new optimal fuzzy logic-based-proportional-integral-derivative (FLPID) controller for load frequency control (LFC) including superconducting magnetic energy storage (SMES) units. Conventionally, the membership functions and control rules of fuzzy logic control are obtained by trial and error method or experiences of designers. To overcome this problem, the multiple tabu search (MTS) algorithm is applied to simultaneously tune PID gains, membership functions and control rules of FLPID controller to minimize frequency deviations of the system against load disturbances. The MTS algorithm introduces additional techniques for improvement of search process such as initialization, adaptive search, multiple searches, crossover and restarting process. Simulation results explicitly show that the performance of the optimum FLPID controller is superior to the conventional PID controller and the non-optimum FLPID controller in terms of the overshoot, settling time and robustness against variations of system parameters

  12. Distribution and abundance of submerged macrophytes, including Myriophyllum spicatum L. (Angiospermae), in a reactor cooling reservoir

    International Nuclear Information System (INIS)

    Grace, J.B.; Tilly, L.J.

    1974-01-01

    The distribution of aquatic macrophytes, including Myriophyllum spicatum L., in a reactor cooling reservoir was analyzed by biomass removal. Samples were collected by use of a corer from hot, warm, and cold stations at progressive distances from a thermal effluent. Standing crop was doubled at the warm station as compared to the cold station due to the enhancement of Myriophyllum spicatum L. However, M. spicatum was least abundant at the hot station where Najas guadalupensis (Spreng.) Morong. predominated. Possible causes for the restriction of M. spicatum from the hot station are given. Maximum rooting depth of vegetation was reduced near the effluent apparently due to a combination of decreased light penetration and a higher photosynthesis-respiration compensation level at higher temperatures. (U.S.)

  13. The Influence of Orthographic Neighborhood Density and Word Frequency on Visual Word Recognition: Insights from RT Distributional Analyses

    Directory of Open Access Journals (Sweden)

    Stephen Wee Hun eLim

    2016-03-01

    Full Text Available The effects of orthographic neighborhood density and word frequency in visual word recognition were investigated using distributional analyses of response latencies in visual lexical decision. Main effects of density and frequency were observed in mean latencies. Distributional analyses, in addition, revealed a density x frequency interaction: for low-frequency words, density effects were mediated predominantly by distributional shifting whereas for high-frequency words, density effects were absent except at the slower RTs, implicating distributional skewing. The present findings suggest that density effects in low-frequency words reflect processes involved in early lexical access, while the effects observed in high-frequency words reflect late postlexical checking processes.

  14. Distribution function of frequency of stellar flares in the Orion association

    International Nuclear Information System (INIS)

    Parsamyan, Eh.S.

    1980-01-01

    Using the chronology of discoveries of new flares and the chronology of confirmation i.e. the time distribution of second flares (Ambartsumian's method), the distribution function of frequency of flares on stars in the Orion association is obtained. A number of stars having different frequencies is also found. It is shown that flare stars with high flare frequency (ν -1 13sup(m). The quantities of flare stars in aggregates determined by two independent methods show that the number of flare stars in Orion association is about 1.5 times greater than in the Pleiades cluster [ru

  15. Frequency distribution of the reduced unit cells of centred lattices from the Protein Data Bank.

    Science.gov (United States)

    Swaminathan, Kunchithapadam

    2012-03-01

    In crystallography, a centred conventional lattice unit cell has its corresponding reduced primitive unit cell. This study presents the frequency distribution of the reduced unit cells of all centred lattice entries of the Protein Data Bank (as of 23 August 2011) in four unit-cell-dimension-based groups and seven interaxial-angle-based subgroups. This frequency distribution is an added layer of support during space-group assignment in new crystals. In addition, some interesting patterns of distribution are discussed as well as how some reduced unit cells could be wrongly accepted as primitive lattices in a different crystal system.

  16. Body Size Diversity and Frequency Distributions of Neotropical Cichlid Fishes (Cichliformes: Cichlidae: Cichlinae)

    OpenAIRE

    Steele, Sarah E.; López-Fernández, Hernán

    2014-01-01

    Body size is an important correlate of life history, ecology and distribution of species. Despite this, very little is known about body size evolution in fishes, particularly freshwater fishes of the Neotropics where species and body size diversity are relatively high. Phylogenetic history and body size data were used to explore body size frequency distributions in Neotropical cichlids, a broadly distributed and ecologically diverse group of fishes that is highly representative of body size d...

  17. Spatial distribution of soil-transmitted helminths, including Strongyloides stercoralis, among children in Zanzibar

    Directory of Open Access Journals (Sweden)

    Stefanie Knopp

    2008-11-01

    Full Text Available A programme periodically distributing anthelminthic drugs to school-aged children for the control of soiltransmitted helminthiasis was launched in Zanzibar in the early 1990s. We investigated the spatial distribution of soiltransmitted helminth infections, including Strongyloides stercoralis, in 336 children from six districts in Unguja, Zanzibar, in 2007. One stool sample per child was examined with the Kato-Katz, Koga agar plate and Baermann methods. The point prevalence of the different helminth infections was compared to the geological characteristics of the study sites. The observed prevalences for Trichuris trichiura, Ascaris lumbricoides, hookworm and S. stercoralis were 35.5%, 12.2%, 11.9% and 2.2%, respectively, with considerable spatial heterogeneity. Whilst T. trichiura and hookworm infections were found in all six districts, no A. lumbricoides infections were recorded in the urban setting and only a low prevalence (2.2% was observed in the South district. S. stercoralis infections were found in four districts with the highest prevalence (4.0% in the West district. The prevalence of infection with any soil-transmitted helminth was highest in the North A district (69.6% and lowest in the urban setting (22.4%. A. lumbricoides, hookworm and, with the exception of the North B district, S. stercoralis infections were observed to be more prevalent in the settings north of Zanzibar Town, which are characterized by alluvial clayey soils, moist forest regions and a higher precipitation. After a decade of large-scale administration of anthelminthic drugs, the prevalence of soil-transmitted helminth infections across Unguja is still considerable. Hence, additional measures, such as improving access to adequate sanitation and clean water and continued health education, are warranted to successfully control soil-transmitted helminthiasis in Zanzibar.

  18. Towards evenly distributed grazing patterns: including social context in sheep management strategies

    Directory of Open Access Journals (Sweden)

    Agustina di Virgilio

    2016-06-01

    Full Text Available Background. A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals’ foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals’ space use patterns, our aim was to explore the potential effects of including animals’ social context into management strategies using domestic sheep grazing in rangelands as case study. Methods. We used GPS data from 19 Merino sheep (approximately 10% of the flock grazing on three different paddocks (with sizes from 80 to 1000 Ha during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets, age, body condition and time since release on habitat selection patterns. Results. We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females used more intensively the most preferred areas and low-ranked (i.e., yearlings used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour. Discussion. Although homogenization and segregation of

  19. Ultra-stable long distance optical frequency distribution using the Internet fiber network.

    Science.gov (United States)

    Lopez, Olivier; Haboucha, Adil; Chanteau, Bruno; Chardonnet, Christian; Amy-Klein, Anne; Santarelli, Giorgio

    2012-10-08

    We report an optical link of 540 km for ultrastable frequency distribution over the Internet fiber network. The stable frequency optical signal is processed enabling uninterrupted propagation on both directions. The robustness and the performance of the link are enhanced by a cost effective fully automated optoelectronic station. This device is able to coherently regenerate the return optical signal with a heterodyne optical phase locking of a low noise laser diode. Moreover the incoming signal polarization variation are tracked and processed in order to maintain beat note amplitudes within the operation range. Stable fibered optical interferometer enables optical detection of the link round trip phase signal. The phase-noise compensated link shows a fractional frequency instability in 10 Hz bandwidth of 5 × 10(-15) at one second measurement time and 2 × 10(-19) at 30,000 s. This work is a significant step towards a sustainable wide area ultrastable optical frequency distribution and comparison network.

  20. Application of Choi—Williams Reduced Interference Time Frequency Distribution to Machinery Diagnostics

    Directory of Open Access Journals (Sweden)

    Howard A. Gaberson

    1995-01-01

    Full Text Available This article discusses time frequency analysis of machinery diagnostic vibration signals. The short time Fourier transform, the Wigner, and the Choi–Williams distributions are explained and illustrated with test cases. Examples of Choi—Williams analyses of machinery vibration signals are presented. The analyses detect discontinuities in the signals and their timing, amplitude and frequency modulation, and the presence of different components in a vibration signal.

  1. MHC allele frequency distributions under parasite-driven selection: A simulation model

    Directory of Open Access Journals (Sweden)

    Radwan Jacek

    2010-10-01

    Full Text Available Abstract Background The extreme polymorphism that is observed in major histocompatibility complex (MHC genes, which code for proteins involved in recognition of non-self oligopeptides, is thought to result from a pressure exerted by parasites because parasite antigens are more likely to be recognized by MHC heterozygotes (heterozygote advantage and/or by rare MHC alleles (negative frequency-dependent selection. The Ewens-Watterson test (EW is often used to detect selection acting on MHC genes over the recent history of a population. EW is based on the expectation that allele frequencies under balancing selection should be more even than under neutrality. We used computer simulations to investigate whether this expectation holds for selection exerted by parasites on host MHC genes under conditions of heterozygote advantage and negative frequency-dependent selection acting either simultaneously or separately. Results In agreement with simple models of symmetrical overdominance, we found that heterozygote advantage acting alone in populations does, indeed, result in more even allele frequency distributions than expected under neutrality, and this is easily detectable by EW. However, under negative frequency-dependent selection, or under the joint action of negative frequency-dependent selection and heterozygote advantage, distributions of allele frequencies were less predictable: the majority of distributions were indistinguishable from neutral expectations, while the remaining runs resulted in either more even or more skewed distributions than under neutrality. Conclusions Our results indicate that, as long as negative frequency-dependent selection is an important force maintaining MHC variation, the EW test has limited utility in detecting selection acting on these genes.

  2. Nonstationary Frequency Analysis of Extreme Floods Using the Time-varying Two-component Mixture Distributions

    Science.gov (United States)

    Yan, L.; Xiong, L.; Liu, D.; Hu, T.; Xu, C. Y.

    2016-12-01

    The basic IID assumption of the traditional flood frequency analysis has been challenged by nonstationarity. The most popular practice for analyzing nonstationarity of flood series is to use a fixed single-type probability distribution incorporated with the time-varying moments. However, the type of probability distribution could be both complex because of distinct flood populations and time-varying under changing environments. To allow the investigation of this complex nature, the time-varying two-component mixture distributions (TTMD) method is proposed in this study by considering the time variations of not only the moments of its component distributions but also the weighting coefficients. Having identified the existence of mixed flood populations based on circular statistics, the proposed TTMD was applied to model the annual maximum flood series (AMFS) of two stations in the Weihe River basin (WRB), with the model parameters calibrated by the meta-heuristic maximum likelihood (MHML) method. The performance of TTMD was evaluated by different diagnostic plots and indexes and compared with stationary single-type distributions, stationary mixture distributions and time-varying single-type distributions. The results highlighted the advantages of using TTMD models and physically-based covariates in nonstationary flood frequency analysis. Besides, the optimal TTMD models were considered to be capable of settling the issue of nonstationarity and capturing the mixed flood populations satisfactorily. It is concluded that the TTMD model is a good alternative in the nonstationary frequency analysis and can be applied to other regions with mixed flood populations.

  3. Finite Time Control for Fractional Order Nonlinear Hydroturbine Governing System via Frequency Distributed Model

    Directory of Open Access Journals (Sweden)

    Bin Wang

    2016-01-01

    Full Text Available This paper studies the application of frequency distributed model for finite time control of a fractional order nonlinear hydroturbine governing system (HGS. Firstly, the mathematical model of HGS with external random disturbances is introduced. Secondly, a novel terminal sliding surface is proposed and its stability to origin is proved based on the frequency distributed model and Lyapunov stability theory. Furthermore, based on finite time stability and sliding mode control theory, a robust control law to ensure the occurrence of the sliding motion in a finite time is designed for stabilization of the fractional order HGS. Finally, simulation results show the effectiveness and robustness of the proposed scheme.

  4. Dependence of exponents on text length versus finite-size scaling for word-frequency distributions

    Science.gov (United States)

    Corral, Álvaro; Font-Clos, Francesc

    2017-08-01

    Some authors have recently argued that a finite-size scaling law for the text-length dependence of word-frequency distributions cannot be conceptually valid. Here we give solid quantitative evidence for the validity of this scaling law, using both careful statistical tests and analytical arguments based on the generalized central-limit theorem applied to the moments of the distribution (and obtaining a novel derivation of Heaps' law as a by-product). We also find that the picture of word-frequency distributions with power-law exponents that decrease with text length [X. Yan and P. Minnhagen, Physica A 444, 828 (2016), 10.1016/j.physa.2015.10.082] does not stand with rigorous statistical analysis. Instead, we show that the distributions are perfectly described by power-law tails with stable exponents, whose values are close to 2, in agreement with the classical Zipf's law. Some misconceptions about scaling are also clarified.

  5. On the Frequency Distribution of Neutral Particles from Low-Energy Strong Interactions

    Directory of Open Access Journals (Sweden)

    Federico Colecchia

    2017-01-01

    Full Text Available The rejection of the contamination, or background, from low-energy strong interactions at hadron collider experiments is a topic that has received significant attention in the field of particle physics. This article builds on a particle-level view of collision events, in line with recently proposed subtraction methods. While conventional techniques in the field usually concentrate on probability distributions, our study is, to our knowledge, the first attempt at estimating the frequency distribution of background particles across the kinematic space inside individual collision events. In fact, while the probability distribution can generally be estimated given a model of low-energy strong interactions, the corresponding frequency distribution inside a single event typically deviates from the average and cannot be predicted a priori. We present preliminary results in this direction and establish a connection between our technique and the particle weighting methods that have been the subject of recent investigation at the Large Hadron Collider.

  6. Designing Better Graphs by Including Distributional Information and Integrating Words, Numbers, and Images

    Science.gov (United States)

    Lane, David M.; Sandor, Aniko

    2009-01-01

    Statistical graphs are commonly used in scientific publications. Unfortunately, graphs in psychology journals rarely portray distributional information beyond central tendency, and few graphs portray inferential statistics. Moreover, those that do portray inferential information generally do not portray it in a way that is useful for interpreting…

  7. GMLC Hawaii Regional Partnership: Distributed Inverter-Based Grid Frequency Support

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Austin; Hoke, Andy

    2017-05-04

    This presentation is part of a panel session at the IEEE ISGT conference on Grid Modernization Initiative projects. This segment of the panel session provides a brief overview of a Hawaii Regional Partnership project focusing grid frequency support from distributed resources on the fastest time scales.

  8. Frequency distribution of ABO and Rh (D) blood group alleles in ...

    African Journals Online (AJOL)

    Background: Frequency distribution of blood groups is important as it is used in modern medicine, genetic research, anthropology, and tracing ancestral relations of humans. The ABO and Rh blood groups are the most important blood groups despite the long list of several other blood groups discovered so far. Aim of the ...

  9. Single-frequency thulium-doped distributed-feedback fibre laser

    DEFF Research Database (Denmark)

    Agger, Søren; Povlsen, Jørn Hedegaard; Varming, Poul

    2004-01-01

    We have successfully demonstrated a single-frequency distributed-feedback (DFB) thulium-doped silica fiber laser emitting at a wavelength of 1735 nm. The laser cavity is less than 5 cm long and is formed by intracore UV-written Bragg gratings with a phase shift. The laser is pumped at 790 nm from...

  10. Study of the performance of collision short time approximation for neutron scattering using discrete frequency distribution

    International Nuclear Information System (INIS)

    D'Oliveira, A.B.; Amorim, E.S. do; Galvao, O.B.

    1981-03-01

    Double differential cross sections for thermal neutrons, based on incoherent approximation, using continum distribution as discrete frequency set are theoretically estimated, regarding two models previously done. The FASTT computer program is used in order to obtain a numerical estimation. (L.C.) [pt

  11. Time-Frequency Distribution of Music based on Sparse Wavelet Packet Representations

    DEFF Research Database (Denmark)

    Endelt, Line Ørtoft

    We introduce a new method for generating time-frequency distributions, which is particularly useful for the analysis of music signals. The method presented here is based on $\\ell1$ sparse representations of music signals in a redundant wavelet packet dictionary. The representations are found using...

  12. Real-Time Analysis of an Active Distribution Network - Coordinated Frequency Control for Islanding Operation

    DEFF Research Database (Denmark)

    Cha, Seung-Tae

    distribution networks makes it possible to operate the distribution networks independently which is called islanding operation. However, it is a challenge to ensure secure and reliable operation of the islanded system due to a num-ber of reasons, e.g. low inertia in the islanded system, intermittency of some...... be used as a benchmark model for smart grid testing purposes. In both cases, the simulation results are compared and pro-vided a desirable performance with very high degree of accuracy. Secondly, the simplified battery model is adopted and has been modeled in the RTDS in order to investigate the role...... of the BESS as a primary frequency regulator during island-ing transition. The effectiveness of proposed primary frequency control strategy is illus-trated by using two test cases (i.e. IEEE 9-bus and Bornholm). In both cases, the fre-quency regulation performance is highly improved without degrading...

  13. Real-Time Analysis of an Active Distribution Network - Coordinated Frequency Control for Islanding Operation

    DEFF Research Database (Denmark)

    Cha, Seung-Tae

    distribution networks makes it possible to operate the distribution networks independently which is called islanding operation. However, it is a challenge to ensure secure and reliable operation of the islanded system due to a num-ber of reasons, e.g. low inertia in the islanded system, intermittency of some...... of the DERs, etc. Particularly during islanding operation, with relatively few DG units, the frequency and voltage control of the islanded system is not straightforward. DG units, specially based on renewable energy sources (RESs), i.e. wind and solar, have an inter-mittent nature and intrinsic...... system (BESS) and two secondary frequency control scenarios with BESS and DG units. During the island-ing transition, the frequency is regulated by the fast-acting primary control of the BESS. The secondary control of the main management system (MMS) detects the status of the BESS and tries to return...

  14. Spatiotemporal variations in the b-value of earthquake magnitude-frequency distributions: Classification and causes

    Science.gov (United States)

    El-Isa, Z. H.; Eaton, David W.

    2014-03-01

    Interpretation of the b-value of earthquake frequency-magnitude distributions has received considerable attention in recent decades. This paper provides a comprehensive review of previous investigations of spatial and temporal variations in b-value, including their classification and possible causes. Based on least-squares regression of seismicity data compiled from the NEIC, IRIS and ISC catalogs, we find an average value of 1.02 ± 0.03 for the whole Earth and its two hemispheres, consistent with the general view that in seismically active regions the long-term average value is close to unity. Nevertheless, wide-ranging b-variations (0.3 ≤ b ≤ 2.5) have been reported in the literature. This variability has been interpreted to arise from one or more of the following factors: prevailing stress state, crustal heterogeneity, focal depth, pore pressure, geothermal gradient, tectonic setting, petrological/environmental/geophysical characteristics, clustering of events, incomplete catalog data, and/or method of calculation. Excluding the latter, all of these factors appear to be linked, directly or indirectly, with the effective state of stress. Although time-dependent changes in b-value are well documented, conflicting observations reveal either a precursory increase or decrease in b value before major earthquakes. Our compilation of published analyses suggests that statistically significant b-variations occur globally on various timescales, including annual, monthly and perhaps diurnal. Taken together, our review suggests that b-variations are most plausibly linked with changes in effective stress.

  15. Frequencies and ethnic distribution of ABO and Rh(D) blood groups in Mauritania: results of first nationwide study.

    Science.gov (United States)

    Hamed, C T; Bollahi, M A; Abdelhamid, I; Med Mahmoud, M A; Ba, B; Ghaber, S; Habti, N; Houmeida, A

    2012-04-01

    There is no data available on the ABO/Rh(D) frequencies in the Mauritanian population. We retrospectively analysed records of a 5-year database that contained ABO/Rh phenotype and ethnic origin of 10 116 volunteers giving blood at the national blood transfusion centre to derive the frequencies of ABO/Rh(D) groups in the Mauritanian population. The two race categories in the country and their sub-ethnic groups: the Moors (whites and black) and the black Africans (Pulhars, Soninkes and Wolof) were included in this study. Globally, group O had the highest frequency (49.10%) followed by A (28.28%), B (18.56%) and AB (4.05%). This order more common in North African populations was found in four of the five ethnic groups composing our population. Allele frequencies were, respectively, 70.20%, 17.74% and 12.04% giving the same order of O > A > B. We observed no significant variation in these frequencies between the different ethnic groups. Rhesus study showed that with a percentage of 94.23% Rh(D) positive is by far the most prevalent, while Rh(D) negative is present only in 5.77% of the total population. This frequency distribution supports the mixed-race composition of the Mauritanian population. © 2011 Blackwell Publishing Ltd.

  16. Maximum natural frequencies of polymer composite micro-beams by optimum distribution of carbon nanotubes

    International Nuclear Information System (INIS)

    Rokni, Hossein; Milani, Abbas S.; Seethaler, Rudolf J.

    2011-01-01

    Highlights: → Optimum distributions of MWCNTs within the polymer micro-beams are obtained. → Natural frequencies of nanocomposite beam enhance if its root portion is reinforced with CNTs. → Adding MWCNTs to pure polymer micro-beams has an insignificant effect on mode shapes. → Fundamental frequency value is improved by 12.6-15.9% for various boundary conditions. → New CNT dispersion equations are suggested based on the optimum CNT loading pattern. -- Abstract: Optimum distribution of multi-walled carbon nanotubes (MWCNTs) within a polymer composite micro-beam is sought to achieve its highest natural frequencies given a weight percent (wt.%) of MWCNTs. To this end, the micro-beam is divided into ten segments which are perfectly bonded to their neighbors. Each segment is made of low-viscosity, thermosetting polyester epoxy/amine resin LY-5052 and is reinforced by MWCNTs. A computer program, written in the Python programming language, is compiled with ABAQUS to generate a three-dimensional (3D) finite element (FE) model of the micro-beam and subsequently to evaluate an optimum CNT distribution under various vibration modes and boundary conditions. The influence of uniform and optimum MWCNT distributions on the natural frequencies, mode shapes and equivalent stiffness of the micro-beams is investigated and the results are compared with those of the pure polymer micro-beam. Subsequently, after acquiring the optimum distribution of the MWCNTs, two new CNT dispersion functions are proposed for maximizing fundamental frequencies of the clamped-free and clamped-clamped micro-beams. The results of the FE analysis reveal that the optimal reinforcement distribution pattern significantly depends on vibration mode shapes, particularly the micro-beam curvature under each mode. It is observed that fundamental frequencies of clamped-free, clamped-guided and clamped-clamped micro-beams are enhanced up to 15.9%, 13.1% and 12.6%, respectively, by choosing optimum MWCNT

  17. Acquisition of 3D temperature distributions in fluid flow using proton resonance frequency thermometry.

    Science.gov (United States)

    Buchenberg, Waltraud B; Wassermann, Florian; Grundmann, Sven; Jung, Bernd; Simpson, Robin

    2016-07-01

    Proton resonance frequency thermometry is well established for monitoring small temperature changes in tissue. Application of the technique to the measurement of complex temperature distributions within fluid flow is of great interest to the engineering community and could also have medical applications. This work presents an experimental approach to reliably measure three-dimensional (3D) temperature fields in fluid flow using proton resonance frequency thermometry. A velocity-compensated three-dimensional gradient echo sequence was used. A flexible pumping system was attached to an MR compatible double pipe heat exchanger. The temperature of two separate flow circuits could be adjusted to produce various three-dimensional spatial temperature distributions within the fluid flow. Validation was performed using MR compatible temperature probes in a uniformly heated flow. A comparative study was conducted with thermocouples in the presence of a spatially varying temperature distribution. In uniformly heated flow, temperature changes were accurately measured to within 0.5 K using proton resonance frequency thermometry, while spatially varying temperature changes measured with MR showed good qualitative agreement with pointwise measurements using thermocouples. Proton resonance frequency thermometry can be used in a variety of complex flow situations to address medical as well as engineering questions. This work makes it possible to gain new insights into fundamental heat transfer phenomena. Magn Reson Med 76:145-155, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  18. Spindle frequency activity in the sleep EEG: individual differences and topographic distribution.

    Science.gov (United States)

    Werth, E; Achermann, P; Dijk, D J; Borbély, A A

    1997-11-01

    The brain topography of EEG power spectra in the frequency range of sleep spindles was investigated in 34 sleep recordings from 20 healthy young men. Referential (F3-A2, C3-A2, P3-A2 and O1-A2) and bipolar derivations (F3-C3, C3-P3 and P3-O1) along the anteroposterior axis were used. Sleep spindles gave rise to a distinct peak in the EEG power spectrum. The distribution of the peak frequencies pooled over subjects and derivations showed a bimodal pattern with modes at 11.5 and 13.0 Hz, and a trough at 12.25 Hz. The large inter-subject variation in peak frequency (range: 1.25 Hz) contrasted with the small intra-subject variation between derivations, non-REM sleep episodes and different nights. In some individuals and/or some derivations, only a single spindle peak was present. The topographic distributions from referential and bipolar recordings showed differences. The power showed a declining trend over consecutive non-REM sleep episodes in the low range of spindle frequency activity and a rising trend in the high range. The functional and topographic heterogeneity of sleep spindles in conjunction with the intra-subject stability of their frequency are important characteristics for the analysis of sleep regulation on the basis of the EEG.

  19. Frequency distribution of Radium-226, Thorium-228 and Potassium-40 concentration in ploughed soils

    International Nuclear Information System (INIS)

    Drichko, V.F.; Krisyuk, B.E.; Travnikova, I.G.; Lisachenko, E.P.; Dubenskaya, M.A.

    1977-01-01

    The results of studying Ra-226, Th-228 and K-40 concentration distribution laws in podsol, chernozem and saline soils are considered. Radionuclide concentrations were determined by gamma-spectrometric method in the samples chosen from arable soil layer according to the generally accepted agrotechnical procedure. Measuring procedure is described. The results show that frequency distributions of radionuclide concentrations transform from asymmetric form in normal coordinates into symmetric form in logarithmic coordinates. The usage of the lognormal law to describe frequency concentration distributions is substantiated. The values of concentration distribution parameters are given. The analysis of the data obtained permits to establish that Ra-226 and Th-228 concentrations in soils distribute lognormally and K-40 concentrations - normally and lognormally. According to the degree of decreasing mean concentrations of Ra-226 and Th-228, soils lie in line: chernozems=chernozem salterns > podsols; and according to the degree of decreasing mean quadratic deviation - in line: podsols>chernozems=salterns. It is necessary to determine the value of mean quadratic deviation and distribution type for full characteristics of the studied soil radioactivity

  20. Regional parent flood frequency distributions in Europe – Part 2: Climate and scale controls

    Directory of Open Access Journals (Sweden)

    J. L. Salinas

    2014-11-01

    Full Text Available This study aims to better understand the effect of catchment scale and climate on the statistical properties of regional flood frequency distributions. A database of L-moment ratios of annual maximum series (AMS of peak discharges from Austria, Italy and Slovakia, involving a total of 813 catchments with more than 25 yr of record length is presented, together with mean annual precipitation (MAP and basin area as catchment descriptors surrogates of climate and scale controls. A purely data-based investigation performed on the database shows that the generalized extreme value (GEV distribution provides a better representation of the averaged sample L-moment ratios compared to the other distributions considered, for catchments with medium to higher values of MAP independently of catchment area, while the three-parameter lognormal distribution is probably a more appropriate choice for drier (lower MAP intermediate-sized catchments, which presented higher skewness values. Sample L-moment ratios do not follow systematically any of the theoretical two-parameter distributions. In particular, the averaged values of L-coefficient of skewness (L-Cs are always larger than Gumbel's fixed L-Cs. The results presented in this paper contribute to the progress in defining a set of "process-driven" pan-European flood frequency distributions and to assess possible effects of environmental change on its properties.

  1. Diversification Rates and the Evolution of Species Range Size Frequency Distribution

    Directory of Open Access Journals (Sweden)

    Silvia Castiglione

    2017-11-01

    Full Text Available The geographic range sizes frequency distribution (RFD within clades is typically right-skewed with untransformed data, and bell-shaped or slightly left-skewed under the log-transformation. This means that most species within clades occupy diminutive ranges, whereas just a few species are truly widespread. A number of ecological and evolutionary explanations have been proposed to account for this pattern. Among the latter, much attention has been given to the issue of how extinction and speciation probabilities influence RFD. Numerous accounts now convincingly demonstrate that extinction rate decreases with range size, both in living and extinct taxa. The relationship between range size and speciation rate, though, is much less obvious, with either small or large ranged species being proposed to originate more daughter taxa. Herein, we used a large fossil database including 21 animal clades and more than 80,000 fossil occurrences distributed over more than 400 million years of marine metazoans (exclusive of vertebrates evolution, to test the relationship between extinction rate, speciation rate, and range size. As expected, we found that extinction rate almost linearly decreases with range size. In contrast, speciation rate peaks at the large (but not the largest end of the range size spectrum. This is consistent with the peripheral isolation mode of allopatric speciation being the main mechanism of species origination. The huge variation in phylogeny, fossilization potential, time of fossilization, and the overarching effect of mass extinctions suggest caution must be posed at generalizing our results, as individual clades may deviate significantly from the general pattern.

  2. Distributed soil loss estimation system including ephemeral gully development and tillage erosion

    Directory of Open Access Journals (Sweden)

    D. A. N. Vieira

    2015-03-01

    Full Text Available A new modelling system is being developed to provide spatially-distributed runoff and soil erosion predictions for conservation planning that integrates the 2D grid-based variant of the Revised Universal Soil Loss Equation, version 2 model (RUSLER, the Ephemeral Gully Erosion Estimator (EphGEE, and the Tillage Erosion and Landscape Evolution Model (TELEM. Digital representations of the area of interest (field, farm or entire watershed are created using high-resolution topography and data retrieved from established databases of soil properties, climate, and agricultural operations. The system utilizes a library of processing tools (LibRaster to deduce surface drainage from topography, determine the location of potential ephemeral gullies, and subdivide the study area into catchments for calculations of runoff and sheet-and-rill erosion using RUSLER. EphGEE computes gully evolution based on local soil erodibility and flow and sediment transport conditions. Annual tillage-induced morphological changes are computed separately by TELEM.

  3. Frequency Distribution of Hearing Disorders Among the Student of Public Elementary School in Neishaboor

    Directory of Open Access Journals (Sweden)

    Dr. Mohammad Kamali

    2000-05-01

    Full Text Available Objectives: determining the frequency distribution of hearing disorders among the student of public elementary school by Otoscopy, Puretone Audiometry, Impedance Audiometiy and questionnaires. Methods and Materials: This study was carried out in a cross - sectional descriptive survey - on 1200 students (600 girls and 600 boys among the student of primary school of Neishabbor, academic year 1376-77 Results: 1- Otoscopy examination; abnormal conditions of external ear canal was found in 14.1% of cases; mostly impacted ceruman (13.6%; Abnormal conditions of tympanic membrane (0.4% and foreign body 0.16%. Abnormal conditions of external ear canal was statistically unmeaningful. (P V=0 .8 2- Impedance Audiometiy: 5. 75% Abnormal tympanograms were observed, mostly type C (3.15% 3- Pure Tone Audiometry: An overall 5.5% hearing loss was found in this population including 3% bilateral and 1.25% unilateral hearing loss. Only conductive hearing loss was found in this population (2.7% in right ear and 3.5% in left ear, PV=0.9. Hearing loss observed mostly in girls but the difference was slight. Family background showed no effects on the hearing disorders.9.8% of cases were in need of medical care and 0.3% were in need of rehabilitation services. Only 28.8% of parents, 36.3% of teachers and 40.9% of afflicted students were aware of the problem.

  4. Use of commercial vessels in survey augmentation: the size-frequency distribution

    Directory of Open Access Journals (Sweden)

    Eric N. Powell

    2006-09-01

    Full Text Available The trend towards use of commercial vessels to enhance survey data requires assessment of the advantages and limitations of various options for their use. One application is to augment information on size-frequency distributions obtained in multispecies trawl surveys where stratum boundaries and sampling density are not optimal for all species. Analysis focused on ten recreationally and commercially important species: bluefish, butterfish, Loligo squid, weakfish, summer flounder, winter flounder, silver hake (whiting, black sea bass, striped bass, and scup (porgy. The commercial vessel took 59 tows in the sampled domain south of Long Island, New York and the survey vessel 18. Black sea bass, Loligo squid, and summer flounder demonstrated an onshore-offshore gradient such that smaller fish were caught disproportionately inshore and larger fish offshore. Butterfish, silver hake, and weakfish were characterized by a southwest-northeast gradient such that larger fish were caught disproportionately northeast of the southwestern-most sector. All sizes of scup, striped bass, and bluefish were caught predominately inshore. Winter flounder were caught predominately offshore. The commercial vessel was characterized by an increased frequency of large catches for most species. Consequently, patchiness was assayed to be higher by the commercial vessel in nearly all cases. The size-frequency distribution obtained by the survey vessel for six of the ten species, bluefish, butterfish, Loligo squid, summer flounder, weakfish, and silver hake, could not be obtained by chance from the size-frequency distribution obtained by the commercial vessel. The difference in sample density did not significantly influence the size-frequency distribution. Of the six species characterized by significant differences in size-frequency distribution between boats, all but one was patchy at the population level and all had one or more size classes so characterized. Although the

  5. Maximum-likelihood methods for array processing based on time-frequency distributions

    Science.gov (United States)

    Zhang, Yimin; Mu, Weifeng; Amin, Moeness G.

    1999-11-01

    This paper proposes a novel time-frequency maximum likelihood (t-f ML) method for direction-of-arrival (DOA) estimation for non- stationary signals, and compares this method with conventional maximum likelihood DOA estimation techniques. Time-frequency distributions localize the signal power in the time-frequency domain, and as such enhance the effective SNR, leading to improved DOA estimation. The localization of signals with different t-f signatures permits the division of the time-frequency domain into smaller regions, each contains fewer signals than those incident on the array. The reduction of the number of signals within different time-frequency regions not only reduces the required number of sensors, but also decreases the computational load in multi- dimensional optimizations. Compared to the recently proposed time- frequency MUSIC (t-f MUSIC), the proposed t-f ML method can be applied in coherent environments, without the need to perform any type of preprocessing that is subject to both array geometry and array aperture.

  6. Development of a distributed polarization-OTDR to measure two vibrations with the same frequency

    Science.gov (United States)

    Pan, Yun; Wang, Feng; Wang, Xiangchuan; Zhang, Mingjiang; Zhou, Ling; Sun, Zhenqing; Zhang, Xuping

    2015-08-01

    A polarization optical time-domain reflectometer (POTDR) can distributedly measure the vibration of fiber by detecting the vibration induced polarization variation only with a polarization analyzer. It has great potential in the monitoring of the border intrusion, structural healthy, anti-stealing of pipeline and so on, because of its simple configuration, fast response speed and distributed measuring ability. However, it is difficult to distinguish two vibrations with the same frequency for POTDR because the signal induced by the first vibration would bury the other vibration induced signal. This paper proposes a simple method to resolve this problem in POTDR by analyzing the phase of the vibration induced signal. The effectiveness of this method in distinguishing two vibrations with the same frequency for POTDR is proved by simulation.

  7. The Distribution and Frequency of the Terms "Pride" and "Prejudice" in Jane Austen's Pride and Prejudice

    Directory of Open Access Journals (Sweden)

    Tanja Dromnes

    2009-03-01

    Full Text Available In this article we examine the title terms of Jane Austen's Pride and Prejudice (1813 with particular attention to their distribution and frequency in the text. Our method is to connect the statistical material gathered on frequency and distribution to a narratological analysis of the terms, with special emphasis on whether they occur within the focalization of the external narrator, or that of character-focalizers. In order to approach this task, we have availed ourselves of the narratological theories of Mieke Bal. We conclude that there is a differentiation among types of focalization in the novel that enhances the thematic structure of match-making. Although Jane Austen wrote and published her major works two centuries ago, they continue to fascinate literary scholars and general readers alike.

  8. Engineering Inertial and Primary-Frequency Response for Distributed Energy Resources: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Dall-Anese, Emiliano [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhao, Changhong [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Guggilam, Swaroop [University of Minnesota; Dhople, Sairaj V [University of Minnesota; Chen, Yu C [University of British Columbia; Zhao, Changhong [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-12-19

    We propose a framework to engineer synthetic-inertia and droop-control parameters for distributed energy resources (DERs) so that the system frequency in a network composed of DERs and synchronous generators conforms to prescribed transient and steady-state performance specifications. Our approach is grounded in a second-order lumped-parameter model that captures the dynamics of synchronous generators and frequency-responsive DERs endowed with inertial and droop control. A key feature of this reduced-order model is that its parameters can be related to those of the originating higher-order dynamical model. This allows one to systematically design the DER inertial and droop-control coefficients leveraging classical frequency-domain response characteristics of second-order systems. Time-domain simulations validate the accuracy of the model-reduction method and demonstrate how DER controllers can be designed to meet steady-state-regulation and transient-performance specifications.

  9. Power conversion distribution system using a resonant high-frequency AC link

    Science.gov (United States)

    Sood, P. K.; Lipo, T. A.

    1986-01-01

    Static power conversion systems based on a resonant high frequency (HF) link offers a significant reduction in the size and weight of the equipment over that achieved with conventional approaches, especially when multiple sources and loads are to be integrated. A faster system response and absence of audible noise are the other principal characteristics of such systems. A conversion configuration based on a HF link which is suitable for applications requiring distributed power is proposed.

  10. Differences in Crossover Frequency and Distribution among Three Sibling Species of Drosophila

    OpenAIRE

    True, J. R.; Mercer, J. M.; Laurie, C. C.

    1996-01-01

    Comparisons of the genetic and cytogenetic maps of three sibling species of Drosophila reveal marked differences in the frequency and cumulative distribution of crossovers during meiosis. The maps for two of these species, Drosophila melanogaster and D. simulans, have previously been described, while this report presents new map data for D. mauritiana, obtained using a set of P element markers. A genetic map covering nearly the entire genome was constructed by estimating the recombination fra...

  11. A two-component generalized extreme value distribution for precipitation frequency analysis

    Czech Academy of Sciences Publication Activity Database

    Rulfová, Zuzana; Buishand, A.; Roth, M.; Kyselý, Jan

    2016-01-01

    Roč. 534, March (2016), s. 659-668 ISSN 0022-1694 R&D Projects: GA ČR(CZ) GA14-18675S Institutional support: RVO:68378289 Keywords : precipitation extremes * two-component extreme value distribution * regional frequency analysis * convective precipitation * stratiform precipitation * Central Europe Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.483, year: 2016 http://www.sciencedirect.com/science/article/pii/S0022169416000500

  12. Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Kapińska, A. D.; Staveley-Smith, L.; Meurer, G. R.; For, B.-Q. [International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, 35 Stirling Hwy, WA 6009 (Australia); Crocker, R. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Bhandari, S.; Callingham, J. R.; Gaensler, B. M.; Hancock, P. J.; Lenc, E. [ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), Sydney NSW (Australia); Hurley-Walker, N.; Seymour, N. [International Centre for Radio Astronomy Research (ICRAR), Curtin University, Bentley, WA 6102 (Australia); Offringa, A. R. [Netherlands Institute for Radio Astronomy (ASTRON), P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Hanish, D. J. [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Ekers, R. D.; Bell, M. E. [CSIRO Astronomy and Space Science (CASS), P.O. Box 76, Epping, NSW 1710 (Australia); Dwarakanath, K. S. [Raman Research Institute, Bangalore 560080 (India); Hindson, L. [Centre of Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140 (New Zealand); McKinley, B., E-mail: anna.kapinska@uwa.edu.au [School of Physics, The University of Melbourne, Parkville, VIC 3010 (Australia); and others

    2017-03-20

    We present new radio continuum observations of NGC 253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC 253 between 76 MHz and 11 GHz. The spectrum is best described as a sum of a central starburst and extended emission. The central component, corresponding to the inner 500 pc of the starburst region of the galaxy, is best modeled as an internally free–free absorbed synchrotron plasma, with a turnover frequency around 230 MHz. The extended emission component of the spectrum of NGC 253 is best described as a synchrotron emission flattening at low radio frequencies. We find that 34% of the extended emission (outside the central starburst region) at 1 GHz becomes partially absorbed at low radio frequencies. Most of this flattening occurs in the western region of the southeast halo, and may be indicative of synchrotron self-absorption of shock-reaccelerated electrons or an intrinsic low-energy cutoff of the electron distribution. Furthermore, we detect the large-scale synchrotron radio halo of NGC 253 in our radio images. At 154–231 MHz the halo displays the well known X-shaped/horn-like structure, and extends out to ∼8 kpc in the z -direction (from the major axis).

  13. Meteorological context for fall experiments including distributions of water vapor, ozone, and carbon monoxide

    Science.gov (United States)

    Danielsen, Edwin F.; Gregory, Gerald L.; Sachse, Glen W.; Hill, G. F.; Gaines, Steven E.

    1987-01-01

    Meteorological contexts for the NASA GTE/CITE 1 fall 1983 flight series are presented and discussed. The large-scale wind, cold cloud, and moisture patterns are illustrated by composite diagrams based on the National Oceanic and Atmospheric Administration 700-, 500-, and 250-mbar analyses and the GOES-West broadband and 6.7-micron (water vapor) infrared photographs. Detailed flight path diagrams are included for seven maritime flights and one continental flight in the free troposphere and boundary layer. For three flights from Hickam Field, in Honolulu, HI, to the Intertropical Convergence Zone, vertical profiles of temperature, dew/frost point departures, wind velocity, and ozone, and carbon monoxide mixing ratios are also presented and discussed. Excellent agreement is demonstrated between the in situ and remote measurements. In particular, the predictive and diagnostic value of the 6.7-micron water vapor photographs is demonstrated.

  14. Frequency distribution of Echinococcus multilocularis and other helminths of foxes in Kyrgyzstan.

    Science.gov (United States)

    Ziadinov, I; Deplazes, P; Mathis, A; Mutunova, B; Abdykerimov, K; Nurgaziev, R; Torgerson, P R

    2010-08-04

    Echinococcosis is a major emerging zoonosis in central Asia. A study of the helminth fauna of foxes from Naryn Oblast in central Kyrgyzstan was undertaken to investigate the abundance of Echinococcus multilocularis in a district where a high prevalence of this parasite had previously been detected in dogs. A total of 151 foxes (Vulpes vulpes) were investigated in a necropsy study. Of these 96 (64%) were infected with E. multilocularis with a mean abundance of 8669 parasites per fox. This indicates that red foxes are a major definitive host of E. multilocularis in this country. This also demonstrates that the abundance and prevalence of E. multilocularis in the natural definitive host are likely to be high in geographical regions where there is a concomitant high prevalence in alternative definitive hosts such as dogs. In addition Mesocestoides spp., Dipylidium caninum, Taenia spp., Toxocara canis, Toxascaris leonina, Capillaria and Acanthocephala spp. were found in 99 (66%), 50 (33%), 48 (32%), 46 (30%), 9 (6%), 34 (23%) and 2 (1%) of foxes, respectively. The prevalence but not the abundance of E. multilocularis decreased with age. The abundance of D. caninum also decreased with age. The frequency distribution of E. multilocularis and Mesocestoides spp. followed a zero-inflated negative binomial distribution, whilst all other helminths had a negative binomial distribution. This demonstrates that the frequency distribution of positive counts and not just the frequency of zeros in the data set can determine if a zero-inflated or non-zero-inflated model is more appropriate. This is because the prevalences of E. multolocularis and Mesocestoides spp. were the highest (and hence had fewest zero counts) yet the parasite distribution nevertheless gave a better fit to the zero-inflated models. Copyright 2010 Elsevier B.V. All rights reserved.

  15. Investigation of electronic transport through a ladder-like graphene nanoribbon including random distributed impurities

    Science.gov (United States)

    Esmaili, Esmat; Mardaani, Mohammad; Rabani, Hassan

    2018-01-01

    The electronic transport of a ladder-like graphene nanoribbon which the on-site or hopping energies of a small part of it can be random is modeled by using the Green's function technique within the nearest neighbor tight-binding approach. We employ a unitary transformation in order to convert the Hamiltonian of the nanoribbon to the Hamiltonian of a tight-binding ladder-like network. In this case, the disturbed part of the system includes the second neighbor hopping interactions. While, the converted Hamiltonian of each ideal part is equivalent to the Hamiltonian of two periodic on-site chains. Therefore, we can insert the self-energies of the alternative on-site tight-binding chains to the inverse of the Green's function matrix of the ladder-like part. In this viewpoint, the conductance is constructed from two trans and cis contributions. The results show that increasing the disorder strength causes the increase and decrease of the conductance of the trans and cis contributions, respectively.

  16. Evaluation of low-frequency operational limit of proposed ITER low-field-side reflectometer waveguide run including miter bends

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guiding [Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy and Plasma Science and Technology Inst. (PSTI); Peebles, W. A. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy and Plasma Science and Technology Inst. (PSTI); Doyle, E. J. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy and Plasma Science and Technology Inst. (PSTI); Crocker, N. A. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy and Plasma Science and Technology Inst. (PSTI); Wannberg, C. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy and Plasma Science and Technology Inst. (PSTI); Lau, Cornwall H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hanson, Gregory R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Doane, John L. [General Atomics, San Diego, CA (United States)

    2017-10-19

    The present design concept for the ITER low-field-side reflectometer transmission line (TL) consists of an ~40 m long, 6.35 cm diameter helically corrugated waveguide (WG) together with ten 90° miter bends. This paper presents an evaluation of the TL performance at low frequencies (33-50 GHz) where the predicted HE11 mode ohmic and mode conversion losses start to increase significantly. Quasi-optical techniques were used to form a near Gaussian beam to efficiently couple radiation in this frequency range into the WG. We observed that the output beams from the guide remained linearly polarized with cross-polarization power levels of ~1.5%-3%. The polarization rotation due to the helical corrugations was in the range ~1°-3°. The radiated beam power profiles typically show excellent Gaussian propagation characteristics at distances >20 cm from the final exit aperture. The round trip propagation loss was found to be ~2.5 dB at 50 GHz and ~6.5 dB at 35 GHz, showing an inverse increase with frequency. This was consistent with updated calculations of miter bend and ohmic losses. At low frequencies (33-50 GHz), the mode purity remained very good at the exit of the waveguide, and the losses are perfectly acceptable for operation in ITER. Finally, the primary challenge may come from the future addition of a Gaussian telescope and other filter components within the corrugated guide, which will likely introduce additional perturbations to the beam profile and an increase in mode-conversion loss.

  17. Body size diversity and frequency distributions of Neotropical cichlid fishes (Cichliformes: Cichlidae: Cichlinae.

    Directory of Open Access Journals (Sweden)

    Sarah E Steele

    Full Text Available Body size is an important correlate of life history, ecology and distribution of species. Despite this, very little is known about body size evolution in fishes, particularly freshwater fishes of the Neotropics where species and body size diversity are relatively high. Phylogenetic history and body size data were used to explore body size frequency distributions in Neotropical cichlids, a broadly distributed and ecologically diverse group of fishes that is highly representative of body size diversity in Neotropical freshwater fishes. We test for divergence, phylogenetic autocorrelation and among-clade partitioning of body size space. Neotropical cichlids show low phylogenetic autocorrelation and divergence within and among taxonomic levels. Three distinct regions of body size space were identified from body size frequency distributions at various taxonomic levels corresponding to subclades of the most diverse tribe, Geophagini. These regions suggest that lineages may be evolving towards particular size optima that may be tied to specific ecological roles. The diversification of Geophagini appears to constrain the evolution of body size among other Neotropical cichlid lineages; non-Geophagini clades show lower species-richness in body size regions shared with Geophagini. Neotropical cichlid genera show less divergence and extreme body size than expected within and among tribes. Body size divergence among species may instead be present or linked to ecology at the community assembly scale.

  18. Oxide vapor distribution from a high-frequency sweep e-beam system

    Energy Technology Data Exchange (ETDEWEB)

    Chow, R.; Tassano, P.L.; Tsujimoto, N.

    1995-03-01

    Oxide vapor distributions have been determined as a function of operating parameters of a high frequency sweep e-beam source combined with a programmable sweep controller. We will show which parameters are significant, the parameters that yield the broadest oxide deposition distribution, and the procedure used to arrive at these conclusions. A design-of-experimental strategy was used with five operating parameters: evaporation rate, sweep speed, sweep pattern (pre-programmed), phase speed (azimuthal rotation of the pattern), profile (dwell time as a function of radial position). A design was chosen that would show which of the parameters and parameter pairs have a statistically significant effect on the vapor distribution. Witness flats were placed symmetrically across a 25 inches diameter platen. The stationary platen was centered 24 inches above the e-gun crucible. An oxide material was evaporated under 27 different conditions. Thickness measurements were made with a stylus profilometer. The information will enable users of the high frequency e-gun systems to optimally locate the source in a vacuum system and understand which parameters have a major effect on the vapor distribution.

  19. Modeling the distribution of ammonia across Europe including bi-directional surface–atmosphere exchange

    Directory of Open Access Journals (Sweden)

    R. J. Wichink Kruit

    2012-12-01

    Full Text Available A large shortcoming of current chemistry transport models (CTM for simulating the fate of ammonia in the atmosphere is the lack of a description of the bi-directional surface–atmosphere exchange. In this paper, results of an update of the surface–atmosphere exchange module DEPAC, i.e. DEPosition of Acidifying Compounds, in the chemistry transport model LOTOS-EUROS are discussed. It is shown that with the new description, which includes bi-directional surface–atmosphere exchange, the modeled ammonia concentrations increase almost everywhere, in particular in agricultural source areas. The reason is that by using a compensation point the ammonia lifetime and transport distance is increased. As a consequence, deposition of ammonia and ammonium decreases in agricultural source areas, while it increases in large nature areas and remote regions especially in southern Scandinavia. The inclusion of a compensation point for water reduces the dry deposition over sea and allows reproducing the observed marine background concentrations at coastal locations to a better extent. A comparison with measurements shows that the model results better represent the measured ammonia concentrations. The concentrations in nature areas are slightly overestimated, while the concentrations in agricultural source areas are still underestimated. Although the introduction of the compensation point improves the model performance, the modeling of ammonia remains challenging. Important aspects are emission patterns in space and time as well as a proper approach to deal with the high concentration gradients in relation to model resolution. In short, the inclusion of a bi-directional surface–atmosphere exchange is a significant step forward for modeling ammonia.

  20. Coastal waters monitoring data: frequency distributions of the principal water quality variables

    Directory of Open Access Journals (Sweden)

    Bianca DI LORENZO

    2006-08-01

    Full Text Available Examining the results of the Italian national programme of marine coastal monitoring, the old problem has arisen about the choice of the most appropriate procedures and methods to validate data and screen preliminary data. Therefore, statistical distributions of water quality parameters have been taken into consideration, in order to assign appropriate frequency distributions to all the routinely measured variables. Each sample distribution has been analysed and defined by a probability density function (p.d.f., by means of a powerful method of data analysis (Johnson 1949 that allows for the computation of statistical parameters of a wide variety of non-normal distributions. The resulting Johnson distributions are then classified depending on four fundamental categories of frequency distributions: normal, log-normal, bounded and unbounded. Theoretical aspects of the method are explained and discussed in an adequate way, so as to allow for practical applications. The shape and nature of these curves require further consideration, in order to understand the behaviour of water quality variables and to make comparison among different coastal zones. To this end, two coastal systems were considered in this work: the Emilia-Romagna coastal area of the NW Adriatic Sea and the Tuscany littoral of the Northern Tyrrhenian Sea. There are notable advantages to the adopted approach. First it offers the possibility to overcome severe constraints requested by the normality assumption, and avoids the troublesome search for the most appropriate transformation function (i.e. for ensuring normality. Second, it avoids searching for other kinds of theoretical distributions that are appropriate for the data. In our approach, the density functions are opportunely integrated, in such a way that, for whatever value assumed by a given variable, the corresponding expected percentage point value under the respective frequency curve, can be calculated, and vice versa. We

  1. An analysis of the temperature distribution in the pipe bending using high frequency induction heating

    International Nuclear Information System (INIS)

    Fukue, Hisayoshi; Mochizuki, Yoji; Nakamura, Harushige; Kobo, Hiroshi; Nitta, Tetsuo; Kawakami, Kiyoshi

    1986-01-01

    A pipe bending apparatus has recently been developed by applying high frequency induction heating. However, the smaller the radius of pipe bending, the greater becomes the reduction in wall thickness and the ovality of the pipe form. This makes it impossible to manufacture pipe bending which will meet the nuclear pipe design code. In order to solve this problem it is crucial to obtain a temperature distributions in a pipe which is moving. It is calculated by giving the following boundary conditions : distribution of the heat generation rate, and that of heat transfer of cooling water. In the process of analyzing these distributions, the following results were obtained. (1) The distribution of the heat generation rate is determined by the sink of energy flux of Poynting vectors. The coil efficiency thus calculated was sixty percent. This figure accords with the test data. (2) The distribution of heat transfer coefficient of cooling water is mainly determined by the rate of liquid film heat transfer, but departure from nucleate boiling and dryout has to be taken into consideration. (3) TRUMP CODE is modified so that the temperature distribution in moving pipes can be calculated by taking the boundary conditions into account. The calculated results were in accordance with the test data. (author)

  2. Magnitude-frequency characteristics and preparatory factors for spatial debris-slide distribution in the northern Faroe Islands

    DEFF Research Database (Denmark)

    Dahl, Mads-Peter Jakob; Jensen, Niels H.; Veihe, Anita

    2013-01-01

    the magnitude and frequency of their debris-slide origins as well as identifying which preparatory factors are responsible for the spatial debris-slide distribution in the landscape. For that purpose a debris-slide inventory was generated from aerial photo interpretation (API), fieldwork and anecdotal sources...... function analysis (DFA). Nine factors containing geological (lithology, dip), geomorphological (slope angle, altitude, aspect; plan and profile curvature) and land use (infield/outfield, sheep density) information were included in the multivariate analysis. Debris-slides larger than 100 m(2) with magnitude...

  3. Determining surface wave attenuation by modeling surface wave amplitudes including finite-frequency focusing and defocusing effects

    Science.gov (United States)

    Ma, Z.; Masters, G.

    2011-12-01

    We have developed a technique that uses cluster analysis method to efficiently measure Rayleigh wave phase and amplitude anomalies. Amplitude anomaly measurements have been made on the vertical components of all permanent stations recording LHZ data from IRIS. We currently consider earthquakes with Ms>5.5 between 1990 and 2004 and correct for source phase and magnitude according to the CMT. This technique leads to a large set of amplitude measurements at 7mHz, 10mHz, 15mHz and 20mHz. We discard data with erroneously large amplitude anomalies (|dlnA|>1) and inconsistent instrument responses and we only use earthquakes recorded by more than 30 stations. Out of about 250000 raw measurements for each frequency, about 140000 measurements are retained for inverting for attenuation structure. Similar to Dalton and Ekstrom (2006), phase and amplitude data are inverted together for phase velocity maps, attenuation maps, and source and receiver terms. However, we use the 2D finite frequency amplitude kernel of Zhou et al, (2004) to model the focusing-defocusing effects. Ray theory, which has been used to date, gives amplitude anomaly predictions which depend strongly on short wavelength structure and so are very sensitive to how phase velocity maps are smoothed. Our resulting attenuation maps show structures correlating well with surface tectonics, with high attenuation in regions of ridges, back-arc basins and western North America, and low attenuation in stable continental shields. The success of getting reasonable attenuation structures demonstrates the feasibility of applying 2D finite frequency amplitude kernel to real data.

  4. Frequency distribution of gastro esophageal reflux disease in inhalation injury: A historical cohort study

    Directory of Open Access Journals (Sweden)

    Ashraf Karbasi

    2015-01-01

    Full Text Available Background: There is no data on the prevalence and the association of gastro esophageal reflux disease (GERD with toxic fume inhalation. Therefore, we aimed to evaluate the frequency distribution of GERD symptoms among the individuals with mild respiratory disorder due to the past history of toxic fume exposure to sulfur mustard (SM. Materials and Methods: In a historical cohort study, subjects were randomly selected from 7000 patients in a database of all those who had a history of previous exposure to a single high dose of SM gas during war. The control group was randomly selected from adjacent neighbors of the patients, and two healthy male subjects were chosen per patient. In this study, we used the validated Persian translation of Mayo Gastroesophageal Reflux Questionnaire to assess the frequency distribution of reflux disease. Results: Relative frequency of GERD symptoms, was found to be significantly higher in the inhalation injury patients with an odds ratio of 8.30 (95% confidence interval [CI]: 4.73-14.55, and after adjustment for cigarette smoking, tea consumption, age, and body mass index, aspirin and chronic cough the odds ratio was found to be 4.41 (95% CI: 1.61-12.07. Conclusion: The most important finding of our study was the major GERD symptoms (heartburn and/or acid regurgitation once or more per week among the individuals with the past history of exposure to SM toxic gas is substantially higher (4.4-fold than normal populations.

  5. Research on Distributed PV Storage Virtual Synchronous Generator System and Its Static Frequency Characteristic Analysis

    Directory of Open Access Journals (Sweden)

    Xiangwu Yan

    2018-03-01

    Full Text Available The increasing penetration rate of grid connected renewable energy power generation reduces the primary frequency regulation capability of the system and poses a challenge to the security and stability of the power grid. In this paper, a distributed photovoltaic (PV storage virtual synchronous generator system is constructed, which realizes the external characteristics of synchronous generator/motor. For this kind of input/output bidirectional devices (e.g., renewable power generation/storage combined systems, pumped storage power stations, battery energy storage systems, and vehicle-to-grid electric vehicles, a synthesis analysis method for system power-frequency considering source-load static frequency characteristics (S-L analysis method is proposed in order to depict the system’s power balance dynamic adjustment process visually. Simultaneously, an inertia matching method is proposed to solve the problem of inertia matching in the power grid. Through the simulation experiment in MATLAB, the feasibility of the distributed PV storage synchronous virtual machine system is verified as well as the effectiveness of S-L analysis method and inertia matching method.

  6. Cired 2015 full paper: DISTRIBUTED AND COORDINATED DEMAND RESPONSE FOR THE SUPPLY OF FREQUENCY CONTAINMENT RESERVE (FCR)

    OpenAIRE

    LEBEL, Gaspard; KUYPERS, Karel; CAIRE, Raphaël; HADJSAID, Nouredine; BEDIOU, Stéphane; GLATIGNY, Alain

    2015-01-01

    The availability of frequency-controlled reserves is essential for any Utility to secure the power system in both interconnected and microgrid contexts. This paper presents a concept of coordinated Distributed Energy Resources (DER), load modulation willing to supply frequency-controlled reserves. These reserves, compliant with both Frequency Containment Reserves (FCR) and Under Frequency Load Shedding (UFLS) requirements, are provided through a structure of Virtual Power Plant (VPP). Physica...

  7. Using frequency maps to explore the distribution function of the Milky Way stellar halo

    Directory of Open Access Journals (Sweden)

    Valluri M.

    2012-02-01

    Full Text Available Resolved surveys of the Milky Way's stellar halo can obtain all 6 phase space coordinates of tens of thousands of individual stars, making it possible to compute their 3-dimensional orbits. When frequency mapping is applied to such orbits they also represent the underlying phase space distribution function since the orbits that the are drawn from 3. A frequency maps clearly separates out the major types of orbits that constitute the DF and their relative abundances. The structure of the frequency maps, especially the locations of resonant orbits, reflects the formation history and shape of the dark matter potential and its orientation relative to the disk. The application of frequency analysis to cosmological hydrodynamic simulations of disk galaxies shows that the orbital families occupied by halo stars and dark matter particles are very similar, implying that stellar halo orbits can be used to constrain the DF of the dark matter halo, possibly impacting the interpretation of results from direct dark matter detection experiments. An application of these methods to a sample of ~ 16,000 Milky Way halo and thick disk stars from the SDSS-SEGUE survey yields a frequency map with strong evidence for resonant trapping of halo stars by the Milky Way disk, in a manner predicted by controlled simulations in which the disk grows adiabatically. The application of frequency analysis methods to current and future phase space data for Milky Way halo stars will provide new insights into the formation history of the different components of the Galaxy and the DF of the halo.

  8. Estimation of target vibration spectra from laser radar backscatter using time-frequency distributions

    Science.gov (United States)

    Cole, Timothy D.; El-Dinary, Ashruf S.

    1993-10-01

    A time-frequency distribution (TFD) signal processor, developed at the Applied Physics Laboratory, is currently under evaluation using simulated signals and actual laser vibration sensor (LVS) data that we collected on various ship targets. Preliminary results for one instantaneous frequency (IF) estimator implementation, the smoothed cross Wigner-Ville Distribution (XWVD), indicate 8 to 10 dB demodulation (CNR) advantage compared to a digital FM limiter-discriminator. A second approach, using the unsmoothed XWVD TFD, demonstrated a 3-5 dB advantage. Regarding spectral estimation, we are investigating performance of our reduced interference distribution (RID) implementation through comparison with the short-time Fourier transform (STFT). From the LVS data processed, indications are that a significant increase in spectral and temporal resolution exists using our RID approach. Our processor also provided improved detectability over the STFT for transient signals and short-lived sinusoids. Significant correlation between accepted acoustic lines and LVS-derived vibration lines are indicated. Details are presented that describe our signal simulation, the LVS measurements, and signal processing implementations along with assumptions based on measured speckle-induced amplitude modulation.

  9. Vehicle-to-Grid Systems for Frequency Regulation in an Islanded Danish Distribution Network

    DEFF Research Database (Denmark)

    Pillai, Jayakrishnan Radhakrishna; Bak-Jensen, Birgitte

    2010-01-01

    vehicles could provide power system ancillary services in the form of power balancing reserves to support the large-scale integration of variable renewable energy sources like wind power. This paper investigates the dynamic frequency response of an islanded Danish distribution system operation with large...... amount of wind power supported by the Vehicle-to-grid systems. The power system simulations are analysed for scenarios with 48% and 65% of wind power penetration. The simulation results show that the V2G systems provide a faster and stable frequency control than the conventional generation units. V2G......Electric vehicles (EVs) have gained significant attention in the recent years due to their prospects in reducing greenhouse gas emissions benefitting the transportation sector directly and the electricity sector indirectly. Vehicle-to-grid (V2G) systems using the battery storages of electric...

  10. Short collision time approximation for neutron scattering using discrete frequency distributions

    International Nuclear Information System (INIS)

    Ryskamp, J.M.

    1980-01-01

    A completely general form for computing any scattering cross section based on the incoherent approximation without extending f(ω) to negative frequencies and without integrating over the complex plane is presented. A simple derivation of the short collision time approximation for discrete frequency distributions is also given. The approximation works well for large incident neutron energies when the duration of a collision is short compared with the natural periods of atomic motion. Single-differential scattering cross sections for light water as computed with the free proton and Nelkin scattering models at 561 0 K, and the short collision time approximation with T/sub eff/ = 1468 0 K, are shown for an incident neutron energy of 1.0 eV. 1 figure

  11. Ultrasound pressure distributions generated by high frequency transducers in large reactors.

    Science.gov (United States)

    Leong, Thomas; Coventry, Michael; Swiergon, Piotr; Knoerzer, Kai; Juliano, Pablo

    2015-11-01

    The performance of an ultrasound reactor chamber relies on the sound pressure level achieved throughout the system. The active volume of a high frequency ultrasound chamber can be determined by the sound pressure penetration and distribution provided by the transducers. This work evaluated the sound pressure levels and uniformity achieved in water by selected commercial scale high frequency plate transducers without and with reflector plates. Sound pressure produced by ultrasonic plate transducers vertically operating at frequencies of 400 kHz (120 W) and 2 MHz (128 W) was characterized with hydrophones in a 2 m long chamber and their effective operating distance across the chamber's vertical cross section was determined. The 2 MHz transducer produced the highest pressure amplitude near the transducer surface, with a sharp decline of approximately 40% of the sound pressure occurring in the range between 55 and 155 mm from the transducer. The placement of a reflector plate 500 mm from the surface of the transducer was shown to improve the sound pressure uniformity of 2 MHz ultrasound. Ultrasound at 400 kHz was found to penetrate the fluid up to 2 m without significant losses. Furthermore, 400 kHz ultrasound generated a more uniform sound pressure distribution regardless of the presence or absence of a reflector plate. The choice of the transducer distance to the opposite reactor wall therefore depends on the transducer plate frequency selected. Based on pressure measurements in water, large scale 400 kHz reactor designs can consider larger transducer distance to opposite wall and larger active cross-section, and therefore can reach higher volumes than when using 2 MHz transducer plates. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  12. Wind and wave frequency distributions for sites around the British Isles

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This report presents wind and wave frequency distributions and roses for forty sites around the British Isles. These have been produced using hindcast wind and wave time series data from the NEXT model, for the combined periods January 1977 to December 1979 and January 1989 to December 1994. The database has been subdivided into eight areas: Hebrides Shelf, seven grid points; West Shetland Shelf, four grid points; Northern North Sea, eight grid points; Central North Sea, eight grid points; Southern North Sea, six grid points; English Channel, two grid points; Celtic Sea, three grid points; Irish Sea, two grid points. (author)

  13. Colony size-frequency distribution of pocilloporid juvenile corals along a natural environmental gradient in the Red Sea

    KAUST Repository

    Lozano-Cortes, Diego

    2015-10-29

    Coral colony size-frequency distributions can be used to assess population responses to local environmental conditions and disturbances. In this study, we surveyed juvenile pocilloporids, herbivorous fish densities, and algal cover in the central and southern Saudi Arabian Red Sea. We sampled nine reefs with different disturbance histories along a north–south natural gradient of physicochemical conditions (higher salinity and wider temperature fluctuations in the north, and higher turbidity and productivity in the south). Since coral populations with negatively skewed size-frequency distributions have been associated with unfavorable environmental conditions, we expected to find more negative distributions in the southern Red Sea, where corals are potentially experiencing suboptimal conditions. Although juvenile coral and parrotfish densities differed significantly between the two regions, mean colony size and size-frequency distributions did not. Results suggest that pocilloporid colony size-frequency distribution may not be an accurate indicator of differences in biological or oceanographic conditions in the Red Sea.

  14. Higher moments method for generalized Pareto distribution in flood frequency analysis

    Science.gov (United States)

    Zhou, C. R.; Chen, Y. F.; Huang, Q.; Gu, S. H.

    2017-08-01

    The generalized Pareto distribution (GPD) has proven to be the ideal distribution in fitting with the peak over threshold series in flood frequency analysis. Several moments-based estimators are applied to estimating the parameters of GPD. Higher linear moments (LH moments) and higher probability weighted moments (HPWM) are the linear combinations of Probability Weighted Moments (PWM). In this study, the relationship between them will be explored. A series of statistical experiments and a case study are used to compare their performances. The results show that if the same PWM are used in LH moments and HPWM methods, the parameter estimated by these two methods is unbiased. Particularly, when the same PWM are used, the PWM method (or the HPWM method when the order equals 0) shows identical results in parameter estimation with the linear Moments (L-Moments) method. Additionally, this phenomenon is significant when r ≥ 1 that the same order PWM are used in HPWM and LH moments method.

  15. Distributed strain measurement in perfluorinated polymer optical fibres using optical frequency domain reflectometry

    International Nuclear Information System (INIS)

    Liehr, Sascha; Wendt, Mario; Krebber, Katerina

    2010-01-01

    We present the latest advances in distributed strain measurement in perfluorinated polymer optical fibres (POFs) using backscatter techniques. Compared to previously introduced poly(methyl methacrylate) POFs, the measurement length can be extended to more than 500 m at improved spatial resolution of a few centimetres. It is shown that strain in a perfluorinated POF can be measured up to 100%. In parallel to these investigations, the incoherent optical frequency domain reflectometry (OFDR) technique is introduced to detect strained fibre sections and to measure distributed length change along the fibre with sub-millimetre resolution by applying a cross-correlation algorithm to the backscatter signal. The overall superior performance of the OFDR technique compared to the optical time domain reflectometry in terms of accuracy, dynamic range, spatial resolution and measurement speed is presented. The proposed sensor system is a promising technique for use in structural health monitoring applications where the precise detection of high strain is required

  16. Improving Frequency Stability Based on Distributed Control of Multiple Load Aggregators

    DEFF Research Database (Denmark)

    Hu, Jianqiang; Cao, Jinde; Guerrero, Josep M.

    2017-01-01

    In the power demand side, responsive loads can provide fast regulation and ancillary services as reserve capacities in interconnected power systems. This paper presents a distributed pinning demand side control (DSC) strategy for coordinating multiple load aggregators, i.e., aggregated responsive...... with a small fraction of load aggregators. Moreover, a multi-step algorithm is proposed to determine the control gains in the DSC, which not only guarantees the stability of the close-loop system, but also restrains the plant disturbance. Furthermore, the distributed pinning DSC algorithm is integrated...... into the traditional centralized proportional-integral-based automatic generation control (AGC) framework, which has formed the coupled secondary frequency control structure. It has been shown that the total power mismatch in each control area is shared with both AGC units and load aggregators, and the system...

  17. Exact results for the Kuramoto model with a bimodal frequency distribution

    DEFF Research Database (Denmark)

    Martens, Erik Andreas; Barreto, E.; Strogatz, S. H.

    2009-01-01

    We analyze a large system of globally coupled phase oscillators whose natural frequencies are bimodally distributed. The dynamics of this system has been the subject of long-standing interest. In 1984 Kuramoto proposed several conjectures about its behavior; ten years later, Crawford obtained...... the first analytical results by means of a local center manifold calculation. Nevertheless, many questions have remained open, especially about the possibility of global bifurcations. Here we derive the system’s stability diagram for the special case where the bimodal distribution consists of two equally......, where all the oscillators are desynchronized; partial synchrony, where a macro- scopic group of phase-locked oscillators coexists with a sea of desynchronized ones; and a standing wave state, where two counter-rotating groups of phase-locked oscillators emerge. Analytical results are presented...

  18. Coordinated control of distributed energy resources to support load frequency control

    International Nuclear Information System (INIS)

    Ravikumar Pandi, V.; Al-Hinai, A.; Feliachi, Ali

    2015-01-01

    Highlights: • We aims to maintain feeder power flow by the coordination of DER units. • The error in feeder flow with respect to scheduled value is used by the controller. • The particle swarm optimization is employed to minimize the error in feeder flow. • Implemented on a transmission system along with 37 bus distribution feeder. • The results of proposed feeder control is analyzed with no feeder control scheme. - Abstract: The control of generating resources to follow the unscheduled load changes is considered to be an essential process in the power system in order to maintain the frequency of power supply. This load frequency control (LFC) problem has been given more importance in the recent smart grid environment because of the impact from high penetration of distributed energy resources (DER) installed at the distribution level. The renewable sources are highly intermittent in nature, so it is required to coordinate and control the DER units to maintain the feeder power flow at substation bus bar which is seen by transmission system operator during the LFC process. This paper aims to identify the impact of distributed generation and its control method to reduce the deviation of feeder power flow from the scheduled value in real time operation. The error in feeder power flow with respect to scheduled value is utilized by the PI controller to estimate the change in power reference of all DER units. The power output of DER units are maintained to reference values by the individual PI controllers. The particle swarm optimization algorithm is employed to minimize the error in feeder power flow by optimally tuning the gain values of all PI controllers. The proposed method is examined on a small transmission system along with the feeder of IEEE 37 bus distribution system with balanced loading condition. The complete system along with DER units is implemented in the MATLAB based stability package named Power Analysis Toolbox (PAT) for performing time domain

  19. Magnitude-frequency characteristics and preparatory factors for spatial debris-slide distribution in the northern Faroe Islands

    Science.gov (United States)

    Dahl, Mads-Peter J.; Mortensen, Lis E.; Jensen, Niels H.; Veihe, Anita

    2013-04-01

    The Faroe Islands in the North Atlantic Ocean are highly susceptible to debris-avalanches and debris-flows originating from debris-slide activity in shallow colluvial soils. To provide data for hazard and risk assessment of debris-avalanches and debris-flows, this study aims at quantifying the magnitude and frequency of their debris-slide origins as well as identifying which preparatory factors are responsible for the spatial debris-slide distribution in the landscape. For that purpose a debris-slide inventory was generated from aerial photo interpretation (API), fieldwork and anecdotal sources, covering a 159 km2 study area in the northern Faroe Islands. A magnitude-cumulative frequency (MCF) curve was derived to predict magnitude dependant debris-slide frequencies, while preparatory factors responsible for spatial debris-slide distribution were quantified through GIS-supported discriminant function analysis (DFA). Nine factors containing geological (lithology, dip), geomorphological (slope angle, altitude, aspect, plan and profile curvature) and land use (infield/outfield, sheep density) information were included in the multivariate analysis. Debris-slides larger than 100 m2 with magnitude expressed as topographic scar area can be predicted from the power-law function: Y = 936.26X- 1.277, r2 = 0.98 while a physical explanation is preferred for the roll-over pattern of smaller slope failures. The DFA is able to correctly classify app. 70% of the modeled terrain units into their pre-determined stable/unstable groups. Preparatory factors responsible for the spatial debris-slide distribution are aspect, slope angle, sheep density, plan curvature and altitude, while influence of the remaining factors is negligible.

  20. Hurricane frequency and landfall distribution for coastal wetlands of the Gulf coast, USA

    Science.gov (United States)

    Doyle, T.W.

    2009-01-01

    The regularity and severity of tropical storms are major determinants controlling ecosystem structure and succession for coastal ecosystems. Hurricane landfall rates vary greatly with high and low frequency for given coastal stretches of the southeastern United States. Site-specific meteorological data of hurricane wind speeds and direction, however, are only available for select populated cities of relatively sparse distribution and inland from the coast. A spatial simulation model of hurricane circulation, HURASIM, was applied to reconstruct chronologies of hurricane wind speeds and vectors for northern Gulf coast locations derived from historical tracking data of North Atlantic tropical storms dating back to 1851. Contrasts of storm frequencies showed that tropical storm incidence is nearly double for Florida coastal ecosystems than the westernmost stretches of Texas coastline. Finer-scale spatial simulations for the north-central Gulf coast exhibited sub-regional differences in storm strength and frequency with coastal position and latitude. The overall pattern of storm incidence in the Gulf basin indicates that the disturbance regime of coastal areas varies greatly along the coast, inland from the coast, and temporally over the period of record. Field and modeling studies of coastal ecosystems will benefit from this retrospective analysis of hurricane incidence and intensity both on a local or regional basis. ?? 2009 The Society of Wetland Scientists.

  1. Repeatability of food frequency assessment tools in relation to the number of items and response categories included

    OpenAIRE

    Bountziouka, V. (Vassiliki); Bathrellou, E. (Eirini); Zazpe, I. (Itziar); Ezquer, L. (Leyre); Martinez-Gonzalez, M.A. (Miguel Ángel); Panagiotakos, D.B. (Demosthenes B.)

    2012-01-01

    Background: Accuracy of a measurement is a cornerstone in research in order to make robust conclusions about the research hypothesis. Objective: To examine whether the number of items (questions) and the number of responses of consumption included in nutritional assessment tools influence their repeatability. Methods: During 2009, 400 participants (250 from Greece, 37±13 yrs, 34% males and 150 participants from Spain, 39±17 yrs, 41% males) completed a diet index with 11-items a...

  2. Joint accurate time and stable frequency distribution infrastructure sharing fiber footprint with research network

    Czech Academy of Sciences Publication Activity Database

    Vojtěch, J.; Šlapák, M.; Škoda, P.; Radil, J.; Havliš, O.; Altmann, M.; Münster, P.; Velč, R.; Kundrát, J.; Altmannová, L.; Vohnout, R.; Horváth, T.; Hůla, M.; Smotlacha, V.; Čížek, Martin; Pravdová, Lenka; Řeřucha, Šimon; Hrabina, Jan; Číp, Ondřej

    2017-01-01

    Roč. 56, č. 2 (2017), s. 1-7, č. článku 027101. ISSN 0091-3286 R&D Projects: GA ČR GB14-36681G Institutional support: RVO:68081731 Keywords : accurate time * stable frequency * wavelength division multiplexing * bidirectional reciprocal path * Sagnac effect Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.082, year: 2016

  3. NODC Standard Product: International ocean atlas Volume 4 - Atlas of temperature / salinity frequency distributions (2 disc set) (NCEI Accession 0101473)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This Atlas presents more than 80,000 plots of the empirical frequency distributions of temperature and salinity for each 5-degree square area of the North Atlantic...

  4. Spectral distribution of the efficiency of terahertz difference frequency generation upon collinear propagation of interacting waves in semiconductor crystals

    International Nuclear Information System (INIS)

    Orlov, Sergei N; Polivanov, Yurii N

    2007-01-01

    Dispersion phase matching curves and spectral distributions of the efficiency of difference frequency generation in the terahertz range are calculated for collinear propagation of interacting waves in zinc blende semiconductor crystals (ZnTe, CdTe, GaP, GaAs). The effect of the pump wavelength, the nonlinear crystal length and absorption in the terahertz range on the spectral distribution of the efficiency of difference frequency generation is analysed. (nonlinear optical phenomena)

  5. Surface-distributed low-frequency asynchronous stimulation delays fatigue of stimulated muscles.

    Science.gov (United States)

    Maneski, Lana Z Popović; Malešević, Nebojša M; Savić, Andrej M; Keller, Thierry; Popović, Dejan B

    2013-12-01

    One important reason why functional electrical stimulation (FES) has not gained widespread clinical use is the limitation imposed by rapid muscle fatigue due to non-physiological activation of the stimulated muscles. We aimed to show that asynchronous low-pulse-rate (LPR) electrical stimulation applied by multipad surface electrodes greatly postpones the occurrence of muscle fatigue compared with conventional stimulation (high pulse rate, HPR). We compared the produced force vs. time of the forearm muscles responsible for finger flexion in 2 stimulation protocols, LPR (fL = 10 Hz) and HPR (fH = 40 Hz). Surface-distributed low-frequency asynchronous stimulation (sDLFAS) doubles the time interval before the onset of fatigue (104 ± 80%) compared with conventional synchronous stimulation. Combining the performance of multipad electrodes (increased selectivity and facilitated positioning) with sDLFAS (decreased fatigue) can improve many FES applications in both the lower and upper extremities. Copyright © 2013 Wiley Periodicals, Inc.

  6. The frequency and distribution of high-velocity gas in the Galaxy

    Science.gov (United States)

    Nichols, Joy S.

    1995-01-01

    The purpose of this study was to estimate the frequency and distribution of high-velocity gas in the Galaxy using UV absorption line measurements from archival high-dispersion IUE spectra and to identify particularly interesting regions for future study. Approximately 500 spectra have been examined. The study began with the creation of a database of all 0 and B stars with b less than or = to 30 deg observed with IUE at high dispersion over its 18-year lifetime. The original database of 2500 unique objects was reduced to 1200 objects which had optimal exposures available. The next task was to determine the distances of these stars so the high-velocity structures could be mapped in the Galaxy. Spectroscopic distances were calculated for each star for which photometry was available. The photometry was acquired for each star using the SIMBAD database. Preference was given to the ubvy system where available; otherwise the UBV system was used.

  7. Discrete- and finite-bandwidth-frequency distributions in nonlinear stability applications

    Science.gov (United States)

    Kuehl, Joseph J.

    2017-02-01

    A new "wave packet" formulation of the parabolized stability equations method is presented. This method accounts for the influence of finite-bandwidth-frequency distributions on nonlinear stability calculations. The methodology is motivated by convolution integrals and is found to appropriately represent nonlinear energy transfer between primary modes and harmonics, in particular nonlinear feedback, via a "nonlinear coupling coefficient." It is found that traditional discrete mode formulations overestimate nonlinear feedback by approximately 70%. This results in smaller maximum disturbance amplitudes than those observed experimentally. The new formulation corrects this overestimation, accounts for the generation of side lobes responsible for spectral broadening, and results in disturbance representation more consistent with the experiment than traditional formulations. A Mach 6 flared-cone example is presented.

  8. LARGE SCALE DISTRIBUTED PARAMETER MODEL OF MAIN MAGNET SYSTEM AND FREQUENCY DECOMPOSITION ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    ZHANG,W.; MARNERIS, I.; SANDBERG, J.

    2007-06-25

    Large accelerator main magnet system consists of hundreds, even thousands, of dipole magnets. They are linked together under selected configurations to provide highly uniform dipole fields when powered. Distributed capacitance, insulation resistance, coil resistance, magnet inductance, and coupling inductance of upper and lower pancakes make each magnet a complex network. When all dipole magnets are chained together in a circle, they become a coupled pair of very high order complex ladder networks. In this study, a network of more than thousand inductive, capacitive or resistive elements are used to model an actual system. The circuit is a large-scale network. Its equivalent polynomial form has several hundred degrees. Analysis of this high order circuit and simulation of the response of any or all components is often computationally infeasible. We present methods to use frequency decomposition approach to effectively simulate and analyze magnet configuration and power supply topologies.

  9. How Old are Lunar Lobate Scarps? 1. Seismic Resetting of Crater Size-Frequency Distributions

    Science.gov (United States)

    Van Der Bogert, Carolyn H.; Clark, Jaclyn D.; Hiesinger, Harald; Banks, Maria E.; Watters, Thomas R.; Robinson, Mark S.

    2018-01-01

    Previous studies have estimated the ages of lunar lobate scarps, some of the youngest tectonic landforms on the Moon, based on the estimated life-times of their fresh morphologies and associated small graben, using crater degradation ages, or via buffered and traditional crater size-frequency distribution (CSFD) measurements. Here, we reexamine five scarps previously dated by Binder and Gunga (1985) with crater degradation ages to benchmark the evaluation of both the buffered and traditional CSFD approaches for determination of absolute model ages (AMAs) at scarps. Both CSFD methods yield similar ages for each individual scarp, indicating that fault activity not only can be measured on the scarp itself, but also in the surrounding terrain - an indication that tectonic activity causes surface renewal both adjacent to and even kilometers distant from scarps. Size-frequency variations in the regions surrounding the scarps are thus useful for studying the extent and severity of the ground motion caused by coseismic slip events during scarp formation. All age determination approaches continue to indicate that lunar lobate scarps were active in the late Copernican, with some scarps possibly experiencing activity within the last 100 Ma.

  10. Analysis and applications of a frequency selective surface via a random distribution method

    International Nuclear Information System (INIS)

    Xie Shao-Yi; Huang Jing-Jian; Yuan Nai-Chang; Liu Li-Guo

    2014-01-01

    A novel frequency selective surface (FSS) for reducing radar cross section (RCS) is proposed in this paper. This FSS is based on the random distribution method, so it can be called random surface. In this paper, the stacked patches serving as periodic elements are employed for RCS reduction. Previous work has demonstrated the efficiency by utilizing the microstrip patches, especially for the reflectarray. First, the relevant theory of the method is described. Then a sample of a three-layer variable-sized stacked patch random surface with a dimension of 260 mm×260 mm is simulated, fabricated, and measured in order to demonstrate the validity of the proposed design. For the normal incidence, the 8-dB RCS reduction can be achieved both by the simulation and the measurement in 8 GHz–13 GHz. The oblique incidence of 30° is also investigated, in which the 7-dB RCS reduction can be obtained in a frequency range of 8 GHz–14 GHz. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  11. Dew Frequency, Duration, Amount, and Distribution in Corn and Soybean During SMEX05

    Science.gov (United States)

    Kabela, E. D.; Hornbuckle, B. K.; Cosh, M. H.; Anderson, M. C.; Gleason, M. L.

    2008-12-01

    Dew affects the brightness temperature of vegetation and backscatter from vegetation at microwave wavelengths. Must this effect must be taken into account in order to avoid corrupting remotely-sensed observations of important ecosystem variables such as soil moisture? As a first step towards answering this question, we report the frequency and duration of dew events, the total amount of dew in the canopy, and the distribution of dew within the canopy for two different types of crop canopy, corn and soybean, during SMEX05, a twenty-one day field experiment conducted during June and July, 2005, in Iowa, USA. We observed dew to be present more than 50% of the time in both corn and soybean at common satellite overpass times of 1:30 and 6:00 CST. Dew was most likely to be present between 12:00 and 6:30 CST, and as late as 9:00 CST. Two different methods to scale the liquid water measured on single leaves to the entire vegetation canopy produced similar results, and we observed dew amounts that were comparable, and in some cases higher, than those that have been shown to affect the microwave brightness temperature and backscatter. The distribution of dew within the canopy among the top and bottom of a leaf and (for corn) the leaf collar may influence its effect on remotely-sensed measurements. We found that this distribution is different for light, moderate, and heavy dew events. A modeling approach will be necessary to estimate dew at larger spatial scales associated with satellite remote sensing. The Atmosphere-Land Exchange (ALEX) model, a land surface process model that accounts for both dewfall and distillation, produced estimates of dew amount and duration that were in agreement with manual observations and observations made with leaf wetness sensors.

  12. Tuning and optimization of the field distribution for 4-rod Radio Frequency Quadrupole linacs

    International Nuclear Information System (INIS)

    Schmidt, Janet Susan

    2014-01-01

    In this thesis, the tuning process of the 4-rod Radio Frequency Quadrupole has been analyzed and a theory for the prediction of the tuning plate's influence on the longitudinal voltage distribution was developed together with RF design options for the optimization of the fringe fields. The basic principles of the RFQ's particle dynamics and resonant behavior are introduced in the theory part of this thesis. All studies that are presented are based on the work on four RFQs of recent linac projects. These RFQs are described in one chapter. Here, the projects are introduced together with details about the RFQ parameters and performance. In the meantime two of these RFQs are in full operation at NSCL at MSU and FNAL. One is operating in the test phase of the MedAustron Cancer Therapy Center and the fourth one for LANL is about to be built. The longitudinal voltage distribution has been studied in detail with a focus on the influence of the RF design with tuning elements and parameters like the electrodes overlap or the distance between stems. The theory for simulation methods for the field flatness that were developed as part of this thesis, as well as its simulation with CST MWS have been analyzed and compared to measurements. The lumped circuit model has proven to predict results with an accuracy that can be used in the tuning process of 4-rod RFQs. Together with results from the tuning studies, the studies on the fringe fields of the 4-rod structure lead to a proposal for a 4-rod RFQ model with an improved field distribution in the transverse and longitudinal electric field.

  13. No effects of power line frequency extremely low frequency electromagnetic field exposure on selected neurobehavior tests of workers inspecting transformers and distribution line stations versus controls.

    Science.gov (United States)

    Li, Li; Xiong, De-fu; Liu, Jia-wen; Li, Zi-xin; Zeng, Guang-cheng; Li, Hua-liang

    2014-03-01

    We aimed to evaluate the interference of 50 Hz extremely low frequency electromagnetic field (ELF-EMF) occupational exposure on the neurobehavior tests of workers performing tour-inspection close to transformers and distribution power lines. Occupational short-term "spot" measurements were carried out. 310 inspection workers and 300 logistics staff were selected as exposure and control. The neurobehavior tests were performed through computer-based neurobehavior evaluation system, including mental arithmetic, curve coincide, simple visual reaction time, visual retention, auditory digit span and pursuit aiming. In 500 kV areas electric field intensity at 71.98% of total measured 590 spots were above 5 kV/m (national occupational standard), while in 220 kV areas electric field intensity at 15.69% of total 701 spots were above 5 kV/m. Magnetic field flux density at all the spots was below 1,000 μT (ICNIRP occupational standard). The neurobehavior score changes showed no statistical significance. Results of neurobehavior tests among different age, seniority groups showed no significant changes. Neurobehavior changes caused by daily repeated ELF-EMF exposure were not observed in the current study.

  14. Model of spur processes in aqueous radiation chemistry including spur overlap and a novel initial hydrated electron distribution

    International Nuclear Information System (INIS)

    Short, D.R.

    1980-01-01

    Results are presented from computer calculations based upon an improved diffusion-kinetic model of the spur which includes a novel initial distribution for the hydrated electron and an approximate mathematical treatment of the overlap of spurs in three dimensions. Experimental data for the decay of the hydrated electron and hydroxyl radical before one in electron-pulse-irradated, solute-free and air-free water are fit wihtin experimental uncertainty by adjustment of the initial spatial distributions of spur intermediates and the average energy deposited in the spur. Using the same values of these parameters, the hydrated electron decay is computed for times from 1 ps 10 μs after the radiatio pulse. The results of such calcuations for various conditions of pulse dose and concentrations of scavengers of individual primary chemical species in the spur are compared with corresponding experimental data obtained predominantly from water and aqueous solutions irradiated with 10 to 15 MeV electron pulses. Very good agreement between calculated and experimental hydrated electron decay in pure water is observed for the entire time range studied when a pulse dose of approximately 7900 rads is modeled, but the calcuated and experimental curves are observed to deviate for times greater than 10 ns nanoseconds when low pulse doses and low scavenger concentrations are considered. It is shown that this deviation is experimental and calculated hydrated electron decay cannot be explained by assuming the presence of a hydrated electron scavenging impurity nor by employing a distribution of nearest neighbor interspur distances to refine the overlap approximation

  15. Extended-bandwidth frequency sweeps of a distributed feedback laser using combined injection current and temperature modulation

    Science.gov (United States)

    Hefferman, Gerald; Chen, Zhen; Wei, Tao

    2017-07-01

    This article details the generation of an extended-bandwidth frequency sweep using a single, communication grade distributed feedback (DFB) laser. The frequency sweep is generated using a two-step technique. In the first step, injection current modulation is employed as a means of varying the output frequency of a DFB laser over a bandwidth of 99.26 GHz. A digital optical phase lock loop is used to lock the frequency sweep speed during current modulation, resulting in a linear frequency chirp. In the second step, the temperature of the DFB laser is modulated, resulting in a shifted starting laser output frequency. A laser frequency chirp is again generated beginning at this shifted starting frequency, resulting in a frequency-shifted spectrum relative to the first recorded data. This process is then repeated across a range of starting temperatures, resulting in a series of partially overlapping, frequency-shifted spectra. These spectra are then aligned using cross-correlation and combined using averaging to form a single, broadband spectrum with a total bandwidth of 510.9 GHz. In order to investigate the utility of this technique, experimental testing was performed in which the approach was used as the swept-frequency source of a coherent optical frequency domain reflectometry system. This system was used to interrogate an optical fiber containing a 20 point, 1-mm pitch length fiber Bragg grating, corresponding to a period of 100 GHz. Using this technique, both the periodicity of the grating in the frequency domain and the individual reflector elements of the structure in the time domain were resolved, demonstrating the technique's potential as a method of extending the sweeping bandwidth of semiconductor lasers for frequency-based sensing applications.

  16. [Frequency, nature and distribution of school sport injuries at different types of schools].

    Science.gov (United States)

    Greier, K; Riechelmann, H

    2012-12-01

    A high percentage of all sports injuries occur during school sports. It was analysed whether there are differences in frequency, nature and distribution of school sport injuries at two different types of schools. School sport injuries of all secondary modern schools (n = 106) and in lower classes of grammar Schools (n = 17) in the federal state of Tyrol, Austria, from the ten school years 2001/02 to 2010/11 were analysed. All physical injuries occurring during school sports and resulting in the consultation of a medical doctor and therefore being reported to the general accident department (Allgemeine Unfallversicherungsanstalt [AUVA]) were assessed. During the evaluation period an average number of 32,935 (±1584) school children attended the two types of schools in Tyrol per year. The average incidence of school sports injuries in this ten-year period in both types of schools was 36.4/1,000 (mean) with a standard deviation of 4.4/1,000 per school child per year. The incidence increased from 30.3 in the school year 2001/02 to 40.4 in the school year 2010/11 (r = 0.91; b = 1.34; p sport injuries at secondary modern schools (37.4 ± 4.9 per 1,000 school children per year) was higher than at the lower classes of grammar schools (32.9 ± 4.0 per 1,000 school children per year; relative risk 1.138; 95% CI = 1.09-1.19; p = 1.8 × 10-8). In addition, the sports injuries of the school year 2010/11 were analysed in detail and a comparison was made between the two types of schools. The distribution pattern of school sports injuries did not show any significant differences between both school types. At the secondary modern schools, as well as in the lower classes of grammar schools, injuries to the upper extremities prevailed (>50%). Ball sports were responsible for every second injury. Secondary modern school pupils had a significantly higher risk of suffering a school sports injury than pupils in the lower classes of grammar schools. The injury pattern did not show

  17. Frequency and Distribution of Tuberculosis Resistance-Associated Mutations between Mumbai, Moldova, and Eastern Cape.

    Science.gov (United States)

    Georghiou, S B; Seifert, M; Catanzaro, D; Garfein, R S; Valafar, F; Crudu, V; Rodrigues, C; Victor, T C; Catanzaro, A; Rodwell, T C

    2016-07-01

    Molecular diagnostic assays, with their ability to rapidly detect resistance-associated mutations in bacterial genes, are promising technologies to control the spread of drug-resistant tuberculosis (DR-TB). Sequencing assays provide detailed information for specific gene regions and can help diagnostic assay developers prioritize mutations for inclusion in their assays. We performed pyrosequencing of seven Mycobacterium tuberculosis gene regions (katG, inhA, ahpC, rpoB, gyrA, rrs, and eis) for 1,128 clinical specimens from India, Moldova, and South Africa. We determined the frequencies of each mutation among drug-resistant and -susceptible specimens based on phenotypic drug susceptibility testing results and examined mutation distributions by country. The most common mutation among isoniazid-resistant (INH(r)) specimens was the katG 315ACC mutation (87%). However, in the Eastern Cape, INH(r) specimens had a lower frequency of katG mutations (44%) and higher frequencies of inhA (47%) and ahpC (10%) promoter mutations. The most common mutation among rifampin-resistant (RIF(r)) specimens was the rpoB 531TTG mutation (80%). The mutation was common in RIF(r) specimens in Mumbai (83%) and Moldova (84%) but not the Eastern Cape (17%), where the 516GTC mutation appeared more frequently (57%). The most common mutation among fluoroquinolone-resistant specimens was the gyrA 94GGC mutation (44%). The rrs 1401G mutation was found in 84%, 84%, and 50% of amikacin-resistant, capreomycin-resistant, and kanamycin (KAN)-resistant (KAN(r)) specimens, respectively. The eis promoter mutation -12T was found in 26% of KAN(r) and 4% of KAN-susceptible (KAN(s)) specimens. Inclusion of the ahpC and eis promoter gene regions was critical for optimal test sensitivity for the detection of INH resistance in the Eastern Cape and KAN resistance in Moldova. (This study has been registered at ClinicalTrials.gov under registration number NCT02170441.). Copyright © 2016, American Society for

  18. Multimilling-Insert Wear Assessment Using Non-Linear Virtual Sensor, Time-Frequency Distribution and Neural Networks

    Science.gov (United States)

    James Li, C.; Tzeng, Tzong-Chyi

    2000-11-01

    The objective of this study is to establish a signal processing methodology that can infer the state of milling insert wear from translational vibration measured on the spindle housing of a milling machine. First, the tool wear signature in a translational vibration is accentuated by mapping the translational vibration into a torsional vibration using a previously identified non-linear relationship between the two, i.e. a virtual sensor. Second, a time-frequency distribution, i.e. a Choi-Williams distribution, is calculated from the torsional vibration. Third, scattering matrices and orthogonalisation are employed to identify the time-frequency components that are best correlated to the state of wear. Fourth, a neural network is trained to estimate the extent of wear from these critical time frequency components. The combination of the virtual sensor, time-frequency analysis and neural network is then validated with data obtained from real cutting tests.

  19. Frequency stabilization of distributed-feedback laser diodes at 1572 nm for lidar measurements of atmospheric carbon dioxide.

    Science.gov (United States)

    Numata, Kenji; Chen, Jeffrey R; Wu, Stewart T; Abshire, James B; Krainak, Michael A

    2011-03-01

    We demonstrate a wavelength-locked laser source that rapidly steps through six wavelengths distributed across a 1572.335 nm carbon dioxide (CO(2)) absorption line to allow precise measurements of atmospheric CO(2) absorption. A distributed-feedback laser diode (DFB-LD) was frequency-locked to the CO(2) line center by using a frequency modulation technique, limiting its peak-to-peak frequency drift to 0.3 MHz at 0.8 s averaging time over 72 hours. Four online DFB-LDs were then offset locked to this laser using phase-locked loops, retaining virtually the same absolute frequency stability. These online and two offline DFB-LDs were subsequently amplitude switched and combined. This produced a precise wavelength-stepped laser pulse train, to be amplified for CO(2) measurements. © 2011 Optical Society of America

  20. Winds from Luminous Late-Type Stars: II. Broadband Frequency Distribution of Alfven Waves

    Science.gov (United States)

    Airapetian, V.; Carpenter, K. G.; Ofman, L.

    2010-01-01

    We present the numerical simulations of winds from evolved giant stars using a fully non-linear, time dependent 2.5-dimensional magnetohydrodynamic (MHD) code. This study extends our previous fully non-linear MHD wind simulations to include a broadband frequency spectrum of Alfven waves that drive winds from red giant stars. We calculated four Alfven wind models that cover the whole range of Alfven wave frequency spectrum to characterize the role of freely propagated and reflected Alfven waves in the gravitationally stratified atmosphere of a late-type giant star. Our simulations demonstrate that, unlike linear Alfven wave-driven wind models, a stellar wind model based on plasma acceleration due to broadband non-linear Alfven waves, can consistently reproduce the wide range of observed radial velocity profiles of the winds, their terminal velocities and the observed mass loss rates. Comparison of the calculated mass loss rates with the empirically determined mass loss rate for alpha Tau suggests an anisotropic and time-dependent nature of stellar winds from evolved giants.

  1. Seasonal Variation and Frequency Distribution of Ectoparasites in Crossbreed Cattle in Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Maria do Socorro Ferraz da Costa

    2014-01-01

    Full Text Available The aims of this study were to evaluate the seasonal variation and frequency distribution of Rhipicephalus (Boophilus microplus, Haematobia irritans, and Dermatobia hominis on crossbred heifers under field conditions in the northeast of Minas Gerais state, southeastern Brazil. From November 2007 to September 2009 (23 months, 40 heifers aged 16.6±2.4 months were divided into groups A (1/4 Holstein × 3/4 Gir and B (1/2 Holstein × 1/2 Gir and had the monthly infestation estimated along with the climatic conditions. The mean maximum and minimum temperatures were 28.5 and 19°C, respectively. The ectoparasites were present on animals in all months of the year. The levels of ticks on the animals were low (3.0±0.2 ticks/animal, with the highest density in midwinter. The temperature was the climatic factor that most influenced the tick levels. The population of H. irritans (13.9±0.3 flies/animal and D. hominis (1.5±0.2 larvae/animal on heifers was more influenced by rainfall and exhibited two population peaks during the year. 1/2 Holstein heifers harbored significantly more H. irritans and D. hominis than 1/4 Holstein heifers. The results are discussed considering the most appropriate periods to apply ectoparasiticides and the genetic make-up of the animals.

  2. Seasonal Variation and Frequency Distribution of Ectoparasites in Crossbreed Cattle in Southeastern Brazil

    Science.gov (United States)

    Ferraz da Costa, Maria do Socorro; Guimarães, Marcos Pezzi; Lima, Walter dos Santos; Ferraz da Costa, Ana Julia; Facury Filho, Elias Jorge; Araujo, Ricardo Nascimento

    2014-01-01

    The aims of this study were to evaluate the seasonal variation and frequency distribution of Rhipicephalus (Boophilus) microplus, Haematobia irritans, and Dermatobia hominis on crossbred heifers under field conditions in the northeast of Minas Gerais state, southeastern Brazil. From November 2007 to September 2009 (23 months), 40 heifers aged 16.6 ± 2.4 months were divided into groups A (1/4 Holstein × 3/4 Gir) and B (1/2 Holstein × 1/2 Gir) and had the monthly infestation estimated along with the climatic conditions. The mean maximum and minimum temperatures were 28.5 and 19°C, respectively. The ectoparasites were present on animals in all months of the year. The levels of ticks on the animals were low (3.0 ± 0.2 ticks/animal), with the highest density in midwinter. The temperature was the climatic factor that most influenced the tick levels. The population of H. irritans (13.9 ± 0.3 flies/animal) and D. hominis (1.5 ± 0.2 larvae/animal) on heifers was more influenced by rainfall and exhibited two population peaks during the year. 1/2 Holstein heifers harbored significantly more H. irritans and D. hominis than 1/4 Holstein heifers. The results are discussed considering the most appropriate periods to apply ectoparasiticides and the genetic make-up of the animals. PMID:26464941

  3. High-frequency oscillations in distributed neural networks reveal the dynamics of human decision making

    Directory of Open Access Journals (Sweden)

    Adrian G Guggisberg

    2008-03-01

    Full Text Available We examine the relative timing of numerous brain regions involved in human decisions that are based on external criteria, learned information, personal preferences, or unconstrained internal considerations. Using magnetoencephalography (MEG and advanced signal analysis techniques, we were able to non-invasively reconstruct oscillations of distributed neural networks in the high-gamma frequency band (60–150 Hz. The time course of the observed neural activity suggested that two-alternative forced choice tasks are processed in four overlapping stages: processing of sensory input, option evaluation, intention formation, and action execution. Visual areas are activated fi rst, and show recurring activations throughout the entire decision process. The temporo-occipital junction and the intraparietal sulcus are active during evaluation of external values of the options, 250–500 ms after stimulus presentation. Simultaneously, personal preference is mediated by cortical midline structures. Subsequently, the posterior parietal and superior occipital cortices appear to encode intention, with different subregions being responsible for different types of choice. The cerebellum and inferior parietal cortex are recruited for internal generation of decisions and actions, when all options have the same value. Action execution was accompanied by activation peaks in the contralateral motor cortex. These results suggest that high-gamma oscillations as recorded by MEG allow a reliable reconstruction of decision processes with excellent spatiotemporal resolution.

  4. Can a one-layer optical skin model including melanin and inhomogeneously distributed blood explain spatially resolved diffuse reflectance spectra?

    Science.gov (United States)

    Karlsson, Hanna; Pettersson, Anders; Larsson, Marcus; Strömberg, Tomas

    2011-02-01

    Model based analysis of calibrated diffuse reflectance spectroscopy can be used for determining oxygenation and concentration of skin chromophores. This study aimed at assessing the effect of including melanin in addition to hemoglobin (Hb) as chromophores and compensating for inhomogeneously distributed blood (vessel packaging), in a single-layer skin model. Spectra from four humans were collected during different provocations using a twochannel fiber optic probe with source-detector separations 0.4 and 1.2 mm. Absolute calibrated spectra using data from either a single distance or both distances were analyzed using inverse Monte Carlo for light transport and Levenberg-Marquardt for non-linear fitting. The model fitting was excellent using a single distance. However, the estimated model failed to explain spectra from the other distance. The two-distance model did not fit the data well at either distance. Model fitting was significantly improved including melanin and vessel packaging. The most prominent effect when fitting data from the larger separation compared to the smaller separation was a different light scattering decay with wavelength, while the tissue fraction of Hb and saturation were similar. For modeling spectra at both distances, we propose using either a multi-layer skin model or a more advanced model for the scattering phase function.

  5. Performance testing of a high frequency link converter for Space Station power distribution system

    Science.gov (United States)

    Sul, S. K.; Alan, I.; Lipo, T. A.

    1989-01-01

    The testing of a brassboard version of a 20-kHz high-frequency ac voltage link prototype converter dynamics for Space Station application is presented. The converter is based on a three-phase six-pulse bridge concept. The testing includes details of the operation of the converter when it is driving an induction machine source/load. By adapting a field orientation controller (FOC) to the converter, four-quadrant operation of the induction machine from the converter has been achieved. Circuit modifications carried out to improve the performance of the converter are described. The performance of two 400-Hz induction machines powered by the converter with simple V/f regulation mode is reported. The testing and performance results for the converter utilizing the FOC, which provides the capability for rapid torque changes, speed reversal, and four-quadrant operation, are reported.

  6. Rock size-frequency distributions analysis at lunar landing sites based on remote sensing and in-situ imagery

    Science.gov (United States)

    Li, Bo; Ling, Zongcheng; Zhang, Jiang; Chen, Jian

    2017-10-01

    Rock populations can supply fundamental geological information about origin and evolution of a planet. In this paper, we used Lunar Reconnaissance Orbiter (LRO) narrow-angle camera (NAC) images to identify rocks at the lunar landing sites (including Chang'e 3 (CE-3), Apollo and Surveyor series). The diameter and area of each identified rock were measured to generate distributions of rock cumulative fractional area and size-frequency on a log-log plot. The two distributions both represented the same shallow slopes at smaller diameters followed by steeper slopes at larger diameters. A reasonable explanation for the lower slopes may be the resolution and space weathering effects. By excluding the smaller diameters, rock populations derived from NAC images showed approximately linear relationships and could be fitted well by power laws. In the last, the entire rock populations derived from both NAC and in-situ imagery could be described by one power function at the lunar landing sites except the CE-3 and Apollo 11 landing sites. This may be because that the process of a large rock breaking down to small rocks even fine particles can be modeled by fractal theories. Thus, rock populations on lunar surfaces can be extrapolated along the curves of rock populations derived from NAC images to smaller diameters. In the future, we can apply rock populations from remote sensing images to estimate the number of rocks with smaller diameters to select the appropriate landing sites for the CE-4 and CE-5 missions.

  7. A statistical approach to quantification of genetically modified organisms (GMO) using frequency distributions.

    Science.gov (United States)

    Gerdes, Lars; Busch, Ulrich; Pecoraro, Sven

    2014-12-14

    According to Regulation (EU) No 619/2011, trace amounts of non-authorised genetically modified organisms (GMO) in feed are tolerated within the EU if certain prerequisites are met. Tolerable traces must not exceed the so-called 'minimum required performance limit' (MRPL), which was defined according to the mentioned regulation to correspond to 0.1% mass fraction per ingredient. Therefore, not yet authorised GMO (and some GMO whose approvals have expired) have to be quantified at very low level following the qualitative detection in genomic DNA extracted from feed samples. As the results of quantitative analysis can imply severe legal and financial consequences for producers or distributors of feed, the quantification results need to be utterly reliable. We developed a statistical approach to investigate the experimental measurement variability within one 96-well PCR plate. This approach visualises the frequency distribution as zygosity-corrected relative content of genetically modified material resulting from different combinations of transgene and reference gene Cq values. One application of it is the simulation of the consequences of varying parameters on measurement results. Parameters could be for example replicate numbers or baseline and threshold settings, measurement results could be for example median (class) and relative standard deviation (RSD). All calculations can be done using the built-in functions of Excel without any need for programming. The developed Excel spreadsheets are available (see section 'Availability of supporting data' for details). In most cases, the combination of four PCR replicates for each of the two DNA isolations already resulted in a relative standard deviation of 15% or less. The aims of the study are scientifically based suggestions for minimisation of uncertainty of measurement especially in -but not limited to- the field of GMO quantification at low concentration levels. Four PCR replicates for each of the two DNA isolations

  8. Frequency distributions of Escherichia coli in the confectionery products offered in retail market in Isfahan

    Directory of Open Access Journals (Sweden)

    Rasoul Rezaei

    2016-06-01

    Full Text Available Introduction: Raw ingredients used in confectionary carry high risk of infection with Escherichia coli. Since confectionaries are offered in the market in quite varied forms and types and there is a great difference in the sanitary status of the confectionaries, this study aimed at evaluation of E.coli   frequency distribution in different types of confectionery products in Isfahan market. In addition, the effect of moisture content, products category and the sanitary level of the confectionaries as well as product types (Industrially or traditionally produced on the contamination level were studied. Materials and methods: A total of 200 samples were randomly collected from confectioneries in Isfahan city through simple random sampling method. Preparation and dilution procedures were conducted under sterile conditions. Samples were cultured on EMB agar medium. Later, some of the positive isolates were randomly selected and confirmed by TSI and IMVIC test. Data analysis was performed using descriptive indices. Also, one way ANOVA and LSD test or independent t test were applied to determine the statistically significant difference between the mean E.coli cell numbers in the categorized groups of sweets. Results: It was found that 19% of the total tested samples were contaminated with E.coli strains. The mean, median and maximum of contamination were (35±.5, (0 and (3.4 CFU/gr, respectively. Moisture content, products category and being traditionally or industrially produced have significant effects on the level of contamination; while, the sanitary status of the traditional confectionaries as graded in this study has no impact on the average E.coli cell count. Discussion and conclusion: Regarding the microbial quality, at least about 25% of the sweets in the market do not meet the national standards of confectionary products. Implementation of strict hygiene regulation in the traditional confectionaries is in need to provide the public with

  9. Determination of High-Frequency Current Distribution Using EMTP-Based Transmission Line Models with Resulting Radiated Electromagnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Mork, B; Nelson, R; Kirkendall, B; Stenvig, N

    2009-11-30

    Application of BPL technologies to existing overhead high-voltage power lines would benefit greatly from improved simulation tools capable of predicting performance - such as the electromagnetic fields radiated from such lines. Existing EMTP-based frequency-dependent line models are attractive since their parameters are derived from physical design dimensions which are easily obtained. However, to calculate the radiated electromagnetic fields, detailed current distributions need to be determined. This paper presents a method of using EMTP line models to determine the current distribution on the lines, as well as a technique for using these current distributions to determine the radiated electromagnetic fields.

  10. Meal Frequency and Nutrient Distribution: What is Ideal for Body Composition?

    OpenAIRE

    Ryan P Lowery

    2014-01-01

    This article explores the effects of meal frequency on protein synthesis, muscle mass and fat mass. Current research appears to indicate that manipulating meal frequency increases net protein balance and body composition when each meal provides an adequate supply of the amino acid leucine to optimize skeletal muscle anabolism. In contrast, research demonstrating no benefits to increased meal frequency generally employed small, inadequate boluses of protein per meal. The purpose of this paper ...

  11. Combined Deterministic and Stochastic Approach to Determine Spatial Distribution of Drought Frequency and Duration in the Great Hungarian Plain

    Science.gov (United States)

    Szabó, J. A.; Kuti, L.; Bakacsi, Zs.; Pásztor, L.; Tahy, Á.

    2009-04-01

    data for the multi-year simulation of SVAT processes. In order to test the elaborated methods, a sub-area of the full domain has been designated as a pilot area for this study. Considering our aims, major achievements with respect to the objectives have been accomplished for the pilot area within the scope of this work includes: - Harmonized 3D grid model to describe hydraulic properties of the unsaturated zone has been created (Pásztor, L. et al 2002 and 2005, Kuti, L. 2007); - The spatially distributed physically based distributed parameter SVAT model DIWA (DIstributed WAtershed) (Szabó, J.A., 2007) has been adapted; - The stochastic characteristics and parameters of the weather generator has been derived from measured data series; - Coupling the stochastic weather generator with the deterministic DIWA SVAT-type model also has been done. In this paper, the results of the coupled (deterministic - stochastic) model simulation based analysis of regional drought frequency and duration for a sub-area of the full domain of the Great Hungarian Plain will be reported. First the harmonized 3D grid model of the hydraulic properties of the unsaturated zone will be presented. Then a brief characterisation of the DIWA model will be given. The Markov chain based stochastic weather generator also will be presented. Finally, the results of multi-year drought frequency and duration analysis at the pilot area and conclusions will be discussed. Keywords: Drought frequency and duration analysis; multivariate analyses; recurrence analyses; extreme events; stochastic weather generator; spatially distributed SVAT model; 3D grid model of hydraulic properties of the unsaturated zone. References: Kuti, L. (2007): Agrogeological investigation of soil fertility limiting factors int he soil-parent roc-groundwater system in Hungary. In: Environment & Progress, Cluj-Napoca, nr. 10. pp. 131-145. Pásztor, L. - Szabó, J. - Bakacsi, Zs. (2002): GIS processing of large scale soil maps in Hungary

  12. Trophic interactions and distribution of some Squaliforme sharks, including new diet descriptions for Deania calcea and Squalus acanthias.

    Directory of Open Access Journals (Sweden)

    Matthew R Dunn

    Full Text Available Squaliforme sharks are a common but relatively vulnerable bycatch in many deep water fisheries. Eleven species of squaliforme shark are commonly caught at depths of 200-1200 m on Chatham Rise, New Zealand, and their diversity suggests they might occupy different niches. The diets of 133 Deania calcea and 295 Squalus acanthias were determined from examination of stomach contents. The diet of D. calcea was characterised by mesopelagic fishes, and S. acanthias by benthic to pelagic fishes, but was more adaptive and included likely scavenging. Multivariate analyses found the most important predictors of diet variability in S. acanthias were year, bottom temperature, longitude, and fish weight. The diet of the nine other commonly caught squaliforme sharks was reviewed, and the spatial and depth distribution of all species on Chatham Rise described from research bottom trawl survey catches. The eleven species had a variety of different diets, and depth and location preferences, consistent with niche separation to reduce interspecific competition. Four trophic groups were identified, characterised by: mesopelagic fishes and invertebrates (Centroselachus crepidater, D. calcea, and Etmopterus lucifer; mesopelagic and benthopelagic fishes and invertebrates (Centroscymnus owstoni, Etmopterus baxteri; demersal and benthic fishes (Centrophorus squamosus, Dalatias licha, Proscymnodon plunketi; and a generalist diet of fishes and invertebrates (S. acanthias. The trophic levels of the species in each of the four groups were estimated as 4.18-4.24, 4.20-4.23, 4.24-4.48, and 3.84 respectively. The diet of Oxynotus bruniensis and Squalus griffini are unknown. The different niches occupied by different species are likely to influence their vulnerability to bottom trawl fisheries. Some species may benefit from fisheries through an increased availability of scavenged prey.

  13. Influence of a distribution of deflecting-mode frequencies on the transient dynamics of cumulative beam breakup

    International Nuclear Information System (INIS)

    Bohn, C.L.; Delayen, J.R.

    1992-01-01

    A distribution of deflecting-mode frequencies in the constituent cavities of a linear accelerator can lead to Q-independent damping of cumulative beam breakup. A probability density for the deflecting-mode frequencies generates an effective transverse wake function. The effective wake function can be used to calculate the transient dynamics of cumulative beam breakup within the framework of a continuum approximation provided the transverse beam displacement changes little over the correlation length of the deflecting-mode frequencies as the beam moves down the linac. We adopt this approach to show that the damping induced by the effective wake function causes the rate of approach to the steady state to depend strongly on the operative probability density for the deflecting-mode frequencies

  14. Predicting species distribution and abundance responses to climate change: why it is essential to include biotic interactions across trophic levels

    NARCIS (Netherlands)

    Van der Putten, W.H.; Macel, M.; Visser, M.E.

    2010-01-01

    Current predictions on species responses to climate change strongly rely on projecting altered environmental conditions on species distributions. However, it is increasingly acknowledged that climate change also influences species interactions. We review and synthesize literature information on

  15. Frequency Distribution in Domestic Microwave Ovens and Its Influence on Heating Pattern.

    Science.gov (United States)

    Luan, Donglei; Wang, Yifen; Tang, Juming; Jain, Deepali

    2017-02-01

    In this study, snapshots of operating frequency profiles of domestic microwave ovens were collected to reveal the extent of microwave frequency variations under different operation conditions. A computer simulation model was developed based on the finite difference time domain method to analyze the influence of the shifting frequency on heating patterns of foods in a microwave oven. The results showed that the operating frequencies of empty and loaded domestic microwave ovens varied widely even among ovens of the same model purchased on the same date. Each microwave oven had its unique characteristic operating frequencies, which were also affected by the location and shape of the load. The simulated heating patterns of a gellan gel model food when heated on a rotary plate agreed well with the experimental results, which supported the reliability of the developed simulation model. Simulation indicated that the heating patterns of a stationary model food load changed with the varying operating frequency. However, the heating pattern of a rotary model food load was not sensitive to microwave frequencies due to the severe edge heating overshadowing the effects of the frequency variations. © 2016 Institute of Food Technologists®.

  16. Investigation of the type, frequency, and sex distribution of fistulas in Crohn's disease

    International Nuclear Information System (INIS)

    Kulke, H.; Kasper, H.; Auer, I.

    1987-01-01

    Various types of fistula development are described in a population of 206 patients with a pravious diagnosis of Crohn's disease. In addition, the frequency of occurence of Crohn's disease in a population and the frequency of Crohn's reoccurrence for a given patient is reported. Furthermore a subdivision of patients with respect to sex is possible. (orig.) [de

  17. Constancy, Distribution, and Frequency of Lepidoptera Defoliators of Eucalyptus grandis and Eucalyptus urophylla (Myrtaceae) in Four Brazilian Regions.

    Science.gov (United States)

    Ribeiro, G T; Zanuncio, J C; de S Tavares, W; de S Ramalho, F; Serrão, J E

    2016-12-01

    The growth of the Brazilian forest sector with monocultures favors the adaptation of Arthropoda pests. The Lepidoptera order includes major pests of Eucalyptus spp. (Myrtaceae). The aim of this work is to study the population constancy, distribution, and frequency of Lepidoptera primary pests of Eucalyptus spp. Lepidoptera pests in Eucalyptus spp. plantations were collected in Três Marias and Guanhães (state of Minas Gerais), Niquelândia (state of Goiás), and Monte Dourado (state of Pará), Brazil, for a period of 5 years, with light traps and captures, every 15 days, for every region. The number of primary pest species (12) has been similar in the four regions, and even with 1.5 to 2.4% of the total species collected, this group has shown a high frequency, especially in Três Marias, Niquelândia, and Monte Dourado, with 66.3, 54.2, and 40.0% of the individuals collected, respectively, for 5 years. The primary pest species have been constant and frequent in all the regions, with population peaks from February to September in Três Marias, February and May in Niquelândia, and from July to September in Monte Dourado. The highest population peaks of these species have been recorded when the Eucalyptus spp. plants are 3 to 6 years old. The Guanhães region is more stable and, therefore, has a lower possibility of outbreaks of the Lepidoptera primary pest species.

  18. Combined effects of food deprivation and food frequency on the amount and temporal distribution of schedule-induced drinking.

    Science.gov (United States)

    Castilla, José Luis; Pellón, Ricardo

    2013-11-01

    Under intermittent food schedules animals develop temporally organized behaviors throughout interfood intervals, with behaviors early in the intervals (interim) normally occurring in excess. Schedule-induced drinking (a prototype of interim, adjunctive behavior) is related to food deprivation and food frequency. This study investigated the interactions that resulted from combining different food-deprivation levels (70%, 80% or 90% free-feeding weights) with different food-occurrence frequencies (15-, 30- or 60-s interfood intervals) in a within-subjects design. Increases in food deprivation and food frequency generally led to increased licking, with greater differences due to food deprivation as interfood intervals became shorter. Distributions of licking were modestly shifted to later in the interfood interval as interfood intervals lengthened, a result that was most marked under 90% food deprivation, which also resulted in flatter distributions. It would therefore appear that food deprivation modulates the licking rate and the distribution of licking in different ways. Effects of food deprivation and food frequency are adequately explained by a theory of adjunctive behavior based on delayed food reinforcement, in contrast to alternative hypotheses. © Society for the Experimental Analysis of Behavior.

  19. Spatial distribution of cold-season lightning frequency in the coastal areas of the Sea of Japan

    Science.gov (United States)

    Tsurushima, Daiki; Sakaida, Kiyotaka; Honma, Noriyasu

    2017-12-01

    The coastal areas of the Sea of Japan are a well-known hotspot of winter lightning activity. This study distinguishes between three common types of winter lightning in that region (types A-C), based on their frequency distributions and the meteorological conditions under which they occur. Type A lightning occurs with high frequency in the Tohoku district. It is mainly caused by cold fronts that accompany cyclones passing north of the Japanese islands. Type B, which occurs most frequently in the coastal areas of the Hokuriku district, is mainly caused by topographically induced wind convergence and convective instability, both of which are associated with cyclones having multiple centers. Type C's lightning frequency distribution pattern is similar to that of type B, but its principal cause is a topographically induced wind convergence generated by cold air advection from the Siberian continent. Type A is most frequently observed from October to November, while types B and C tend to appear from November to January, consistent with seasonal changes in lightning frequency distribution in Japan's Tohoku and Hokuriku districts.

  20. Distributed Generation Integration in the Electric Grid: Energy Storage System for Frequency Control

    Directory of Open Access Journals (Sweden)

    Maurizio Delfanti

    2014-01-01

    Full Text Available During the last few years generation from renewable energy sources (RESs has grown considerably in European electrical networks. Transmission system operators are greatly concerned about the impact of RESs on the operational security and efficiency of their networks and more in general of the ENTSO-E interconnected system. Grid codes are to be revised in order to harmonise the rules regarding the connection of RES power plants. A main issue concerns frequency control: frequency is greatly affected by RESs intermittency and its deviations must be limited as much as possible in order to guarantee a suitable level of power quality. To improve frequency stability, in the future, Grid codes could extend frequency control requirements also to RES units, whereas today they are applied only to conventional power plants. Energy storage systems can be a possible solution to increase the flexibility and performance of RES power plants: they allow generators to modulate their power injections without wasting renewable energy. In this paper, the authors studied the suitability of extending frequency control to RES units integrating them with energy storage systems. In particular, the paper focuses on the impact of frequency control on the storage lifetime by analysing the power charge/discharge in response to real frequency oscillations.

  1. Generation of low-frequency drift pulse trains by direct modulation of a distributed-feedback laser array

    Science.gov (United States)

    Kuroda, Keiji; Yoshikuni, Yuzo

    2016-01-01

    We propose a simple method to generate low-frequency drift pulse trains by direct modulation of a laser diode system consisting of a distributed-feedback laser array and a semiconductor optical amplifier. We measure the temporal profiles, beat signals and spectra of pulses generated under three different sets of conditions. We found that low-frequency drift pulse trains are generated by application of a DC voltage to one of the laser diodes and a pulse voltage to the semiconductor optical amplifier.

  2. Coordinated Primary and Secondary Control with Frequency-Bus-Signaling for Distributed Generation and Storage in Islanded Microgrids

    DEFF Research Database (Denmark)

    Wu, Dan; Tang, Fen; Dragicevic, Tomislav

    2013-01-01

    In this paper, a distributed coordinated control scheme based on frequency-bus-signaling (FBS) method for a low-voltage AC three phase microgrid is proposed. The control scheme is composed by two levels. Firstly a primary local control which is different for the DGs and the ESS is proposed. The ESS...... control is implemented to restore the frequency deviation produced by the primary ESS controller while preserving the coordinated control performance. Real-time simulation results show the feasibility of the proposed approach by showing the operation of the microgrid in different scenarios....

  3. Tailoring electron energy distribution functions through energy confinement in dual radio-frequency driven atmospheric pressure plasmas

    Energy Technology Data Exchange (ETDEWEB)

    O' Neill, C.; Waskoenig, J. [Centre for Plasma Physics, School of Maths and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Gans, T. [Centre for Plasma Physics, School of Maths and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom)

    2012-10-08

    A multi-scale numerical model based on hydrodynamic equations with semi-kinetic treatment of electrons is used to investigate the influence of dual frequency excitation on the effective electron energy distribution function (EEDF) in a radio-frequency driven atmospheric pressure plasma. It is found that variations of power density, voltage ratio, and phase relationship provide separate control over the electron density and the mean electron energy. This is exploited to directly influence both the phase dependent and time averaged effective EEDF. This enables tailoring the EEDF for enhanced control of non-equilibrium plasma chemical kinetics at ambient pressure and temperature.

  4. Design and Quasi-Equilibrium Analysis of a Distributed Frequency-Restoration Controller for Inverter-Based Microgrids

    Energy Technology Data Exchange (ETDEWEB)

    Ainsworth, Nathan G [ORNL; Grijalva, Prof. Santiago [Georgia Institute of Technology, Atlanta

    2013-01-01

    This paper discusses a proposed frequency restoration controller which operates as an outer loop to frequency droop for voltage-source inverters. By quasi-equilibrium analysis, we show that the proposed controller is able to provide arbitrarily small steady-state frequency error while maintaing power sharing between inverters without need for communication or centralized control. We derive rate of convergence, discuss design considerations (including a fundamental trade-off that must be made in design), present a design procedure to meet a maximum frequency error requirement, and show simulation results verifying our analysis and design method. The proposed controller will allow flexible plug-and-play inverter-based networks to meet a specified maximum frequency error requirement.

  5. Controller design for flexible, distributed parameter mechanical arms via combined state space and frequency domain techniques

    Science.gov (United States)

    Book, W. J.; Majett, M.

    1982-01-01

    The potential benefits of the ability to control more flexible mechanical arms are discussed. A justification is made in terms of speed of movement. A new controller design procedure is then developed to provide this capability. It uses both a frequency domain representation and a state variable representation of the arm model. The frequency domain model is used to update the modal state variable model to insure decoupled states. The technique is applied to a simple example with encouraging results.

  6. Improving ecological risk assessment by including bioavailability into species sensitivity distributions: an example for plants exposed to nickel in soil

    NARCIS (Netherlands)

    Semenzin, E.; Temminghoff, E.J.M.; Marcomini, A.

    2007-01-01

    The variability of species sensitivity distribution (SSD) due to contaminant bioavailability in soil was explored by using nickel as metal of concern. SSDs of toxicity test results of Avena sativa L. originating from different soils and expressed as total content and available (0.01 M CaCl2)

  7. Including Remote Participants and Artifacts: Visual, Audio, and Tactile Modalities in an Ethnographic Study of Globally Distributed Engineers

    DEFF Research Database (Denmark)

    Bjørn, Pernille; Pederson, Thomas

    2011-01-01

    In this paper we study how globally distributed Danish and Indian engineers co-construct and reconfigure a shared socio-technical collaborative place for global collaborative interaction: War Room meetings. We investigate the empirical case of War Room meetings based on three modalities in which ...

  8. Computation of aquatic primary production: Extended formalism to include effect of angular and spectral distribution of light

    Digital Repository Service at National Institute of Oceanography (India)

    Sathyendranath, S.; Platt, T.

    and utilization by algal cells. Neglecting the effect of angular distribution on the light absorbed by phytoplankton can lead to underestimation of primary production. For the stations studied as examples, the minimum correction required is 5-l3% for daily, column-integrated...

  9. Innovation in globally distributed teams: the role of LMX, communication frequency, and member influence on team decisions.

    Science.gov (United States)

    Gajendran, Ravi S; Joshi, Aparna

    2012-11-01

    For globally distributed teams charged with innovation, member contributions to the team are crucial for effective performance. Prior research, however, suggests that members of globally distributed teams often feel isolated and excluded from their team's activities and decisions. How can leaders of such teams foster member inclusion in team decisions? Drawing on leader-member exchange (LMX) theory, we propose that for distributed teams, LMX and communication frequency jointly shape member influence on team decisions. Findings from a test of our hypotheses using data from 40 globally distributed teams suggest that LMX can enhance member influence on team decisions when it is sustained through frequent leader-member communication. This joint effect is strengthened as team dispersion increases. At the team level, member influence on team decisions has a positive effect on team innovation. (c) 2012 APA, all rights reserved.

  10. Analytical investigation of response of birefringent fiber Bragg grating sensors in distributed monitoring system based on optical frequency domain reflectometry

    Science.gov (United States)

    Wada, D.; Murayama, H.

    2014-01-01

    When Fiber Bragg gratings (FBGs) are used as strain sensors, both longitudinal and lateral strain can be applied uniformly or non-uniformly over the length of the FBGs. In order for the demodulation of such FBG signal, this paper investigates the response of birefringent FBGs which are monitored by distributed measurement system based on optical frequency domain reflectometry. A numerical model of the distributed measurement system is built based on piece-wise uniform approach, which considers polarization states of propagating lights. The numerical model simulates analytical response of birefringent FBGs especially when birefringence induces power fluctuations in the distributed spectra, which can be noise or new opportunity for sensitive monitoring of birefringence. Simulation results show the relationships between the power fluctuations and the polarization states of the propagating lights. Consequently, appropriate methods of polarization control for sensitive distributed birefringent FBG monitoring are discussed.

  11. FREQUENCY DISTRIBUTIONS OF 90SR AND 137CS CONCENTRATIONS IN AN ECOSYSTEM OF THE 'RED FOREST' AREA IN THE CHERNOBYL EXCLUSION ZONE

    Energy Technology Data Exchange (ETDEWEB)

    Farfan, E.; Jannik, T.; Caldwell, E.

    2011-10-01

    In the most highly contaminated region of the Chernobyl Exclusion Zone: the 'Red Forest' site, the accumulation of the major dose-affecting radionuclides ({sup 90}Sr and {sup 137}Cs) within the components of an ecological system encompassing 3,000 m{sup 2} were characterized. The sampled components included soils (top 0-10 cm depth), Molina caerulea (blue moor grass), Camponotus vagus (carpenter ants) and Pelobates fuscus (spade-footed toad). In a comparison among the components of this ecosystem, the {sup 90}Sr and {sup 137}Cs concentrations measured in 40 separate grids exhibited significant differences, while the frequency distribution of the values were close to a logarithmically normal leptokurtic distribution with a significant right-side skew. While it is important to identify localized areas of high contamination or 'hot spots,' including these values in the arithmetic mean may overestimate the exposure risk. In component sample sets that exhibited logarithmically normal distribution, the geometrical mean more accurately characterizes a site. Ideally, risk assessment is most confidently achieved when the arithmetic and geometrical means are most similar, meaning the distribution approaches normal. Through bioaccumulation, the highest concentrations of {sup 90}Sr and {sup 137}Cs were measured in the blue moor grass and spade-footed toad. These components also possessed distribution parameters that shifted toward a normal distribution.

  12. Low Frequency Electrostatic Waves in Weakly Inhomogeneous Magnetoplasma Modeled by Lorentzian (kappa) Distributions

    National Research Council Canada - National Science Library

    Basu, Bamandas

    2008-01-01

    Linear dispersion relations for electrostatic waves in spatially inhomogeneous, current-carrying anisotropic plasma, where the equilibrium particle velocity distributions are modeled by various Lorentzian (kappa...

  13. High frequency compressional wave speed and attenuation measurements in water-saturated granular media with unimodal and bimodal grain size distributions.

    Science.gov (United States)

    Yang, Haesang; Seong, Woojae

    2018-02-01

    Compressional wave speed and attenuation were measured for water-saturated granular media employing five kinds of glass beads having unimodal and bimodal grain size distributions. Glass beads with grain sizes ranging from 250 to 850  μm were used for the acoustic measurements at a frequency range from 350 kHz to 1.1 MHz, which includes the transition range where scattering and non-scattering losses co-exist. The compressional wave speed and attenuation data are presented as a function of frequency and grain size distribution. The compressional wave speed and attenuation data show a variety of frequency dependencies for varying grain size distribution. The observed acoustic properties are investigated for the volume ratio of larger and smaller sized grains in the mixed bimodal media. Also, the measured results are compared with the empirical multiple scattering formula as a function of Rayleigh parameter  kd (product of wavenumber in the water k and mean grain diameter of the glass beads d) using weighted mean grain size. The measured results are also discussed, focusing on the geophysical difference between unimodal and bimodal mixed grains.

  14. Comparison of minute distribution frequency for anesthesia start and end times from an anesthesia information management system and paper records.

    Science.gov (United States)

    Phelps, Michael; Latif, Asad; Thomsen, Robert; Slodzinski, Martin; Raghavan, Rahul; Paul, Sharon Leigh; Stonemetz, Jerry

    2017-08-01

    Use of an anesthesia information management system (AIMS) has been reported to improve accuracy of recorded information. We tested the hypothesis that analyzing the distribution of times charted on paper and computerized records could reveal possible rounding errors, and that this effect could be modulated by differences in the user interface for documenting certain event times with an AIMS. We compared the frequency distribution of start and end times for anesthesia cases completed with paper records and an AIMS. Paper anesthesia records had significantly more times ending with "0" and "5" compared to those from the AIMS (p < 0.001). For case start times, AIMS still exhibited end-digit preference, with times whose last digits had significantly higher frequencies of "0" and "5" than other integers. This effect, however, was attenuated compared to that for paper anesthesia records. For case end times, the distribution of minutes recorded with AIMS was almost evenly distributed, unlike those from paper records that still showed significant end-digit preference. The accuracy of anesthesia case start times and case end times, as inferred by statistical analysis of the distribution of the times, is enhanced with the use of an AIMS. Furthermore, the differences in AIMS user interface for documenting case start and case end times likely affects the degree of end-digit preference, and likely accuracy, of those times.

  15. Plasma Temperature Determination of Hydrogen Containing High-Frequency Electrodeless Lamps by Intensity Distribution Measurements of Hydrogen Molecular Band

    OpenAIRE

    Gavare, Zanda; Revalde, Gita; Skudra, Atis

    2010-01-01

    The goal of the present work was the investigation of the possibility to use intensity distribution of the Q-branch lines of the hydrogen Fulcher-α diagonal band (d3Πu−→a3∑g+ electronic transition; Q-branch with v=v′=2) to determine the temperature of hydrogen containing high-frequency electrodeless lamps (HFEDLs). The values of the rotational temperatures have been obtained from the relative intensity distributions for hydrogen-helium and hydrogen-argon HFEDLs depending on the applied curren...

  16. Frequency analysis for planned islanding operation in the Danish distribution system - Bornholm

    DEFF Research Database (Denmark)

    Chen, Yu; Xu, Zhao; Østergaard, Jacob

    2008-01-01

    The power system in the Danish island Bornholm is a distribution system with a high penetration of wind generation, which is representative for expected future power systems. During the period from 11th to 14th September 2007, the Distribution System Operator (DSO) Ostkraft in Bornholm conducted ...

  17. A Low-Order System Frequency Response Model for DFIG Distributed Wind Power Generation Systems Based on Small Signal Analysis

    Directory of Open Access Journals (Sweden)

    Rui Quan

    2017-05-01

    Full Text Available Integrating large amounts of wind power into power systems brings a large influence on the dynamic frequency response characteristic (DFRC. The traditional low-order system frequency response (SFR model is no longer applicable at the current time. Based on the small signal analysis theory, a set of novel low-order SFR models for doubly-fed induction generator (DFIG distributed wind power generation systems (DWPGS are derived under low, medium, and high wind speed conditions, respectively. Time-domain simulations have been conducted on PSCAD/EMTDC, and the novel SFR model is tested and evaluated on a real system. The simulation results from the novel model agree with those from the detailed model. The novel SFR model can also directly show the impact of the initial wind speed and auxiliary frequency controller (AFC parameters on DFRC, but not on the detailed model.

  18. Diversity, frequency, and geographic distribution of facultative bacterial endosymbionts in introduced aphid pests.

    Science.gov (United States)

    Sepúlveda, Daniela A; Zepeda-Paulo, Francisca; Ramírez, Claudio C; Lavandero, Blas; Figueroa, Christian C

    2017-06-01

    Facultative bacterial endosymbionts in insects have been under intense study during the last years. Endosymbionts can modify the insect's phenotype, conferring adaptive advantages under environmental stress. This seems particularly relevant for a group of worldwide agricultural aphid pests, because endosymbionts modify key fitness-related traits, including host plant use, protection against natural enemies and heat tolerance. Aimed to understand the role of facultative endosymbionts on the success of introduced aphid pests, the distribution and abundance of 5 facultative endosymbionts (Hamiltonella defensa, Regiella insecticola, Serratia symbiotica, Rickettsia and Spiroplasma) were studied and compared in 4 cereal aphids (Sitobion avenae, Diuraphis noxia, Metopolophium dirhodum and Schizaphis graminium) and in the pea aphid Acyrthosiphon pisum complex from 2 agroclimatic zones in Chile. Overall, infections with facultative endosymbionts exhibited a highly variable and characteristic pattern depending on the aphid species/host race and geographic zone, which could explain the success of aphid pest populations after their introduction. While S. symbiotica and H. defensa were the most frequent endosymbionts carried by the A. pisum pea-race and A. pisum alfalfa-race aphids, respectively, the most frequent facultative endosymbiont carried by all cereal aphids was R. insecticola. Interestingly, a highly variable composition of endosymbionts carried by S. avenae was also observed between agroclimatic zones, suggesting that endosymbionts are responding differentially to abiotic variables (temperature and precipitations). In addition, our findings constitute the first report of bacterial endosymbionts in cereal aphid species not screened before, and also the first report of aphid endosymbionts in Chile. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  19. Visual CRO display of pulse height distribution including discriminator setting for a single channel X-ray analyser

    International Nuclear Information System (INIS)

    Shaw, S.E.

    1979-01-01

    An outline for a simple pulse spectroscope which attaches to a standard laboratory CRO is presented. The peak amplitude voltage of each pulse from the linear amplifier of a single channel X-ray analyser is stored for the duration of one oscilloscope trace. For each amplifier pulse, input from the discriminator is tested and if these is coincidence of pulses the oscilloscope beam is blanked for approximately the first 2 cm of its traverse across the screen. Repetition of pulses forms a pulse height distribution with a rectangular dark area marking the position of the discriminator window. (author)

  20. Radio-frequency properties of stacked long Josephson junctions with nonuniform bias current distribution

    DEFF Research Database (Denmark)

    Filatrella, G; Pedersen, Niels Falsig

    1999-01-01

    We have numerically investigated the behavior of stacks of long Josephson junctions considering a nonuniform bias profile. In the presence of a microwave field the nonuniform bias, which favors the formation of fluxons, can give rise to a change of the sequence of radio-frequency induced steps...

  1. All-Optical Frequency Modulated High Pressure MEMS Sensor for Remote and Distributed Sensing

    DEFF Research Database (Denmark)

    Reck, Kasper; Thomsen, Erik Vilain; Hansen, Ole

    2011-01-01

    We present the design, fabrication and characterization of a new all-optical frequency modulated pressure sensor. Using the tangential strain in a circular membrane, a waveguide with an integrated nanoscale Bragg grating is strained longitudinally proportional to the applied pressure causing a sh...

  2. The frequency and distribution of recent landslides in three montane tropical regions of Puerto Rico

    Science.gov (United States)

    Matthew C. Larsen; Angel J. Torres-Sanchez

    1998-01-01

    Landslides are common in steep mountainous areas of Puerto Rico where mean annual rainfall and the frequency of intense storms are high. Each year, landslides cause extensive damage to property and occasionally result in loss of life. Average population density is high, 422 peoplerkm2, and is increasing. This increase in population density is accompanied by growing...

  3. A low-frequency distributed aperture array for radio astronomy in space

    NARCIS (Netherlands)

    Boonstra, A.J.; Saks, N.; Falcke, H.; Klein-Wolt, M.; Bentum, Marinus Jan; Rajan, R.T.; Rajan, Raj; Wijnholds, S.J.; Arts, M.; van 't Klooster, K.; Beliën, F.

    2010-01-01

    The frequency band below 30 MHz is one of the last unexplored bands in radio astronomy. This band is well suited for studying the early cosmos at high hydrogen redshifts, the so-called dark ages, extragalactic surveys, (extra) solar planetary bursts, and high energy particle physics. In addition,

  4. DARIS : a low-frequency distributed aperture array for radio astronomy in space

    NARCIS (Netherlands)

    Boonstra, A.J.; Saks, N.; Falcke, H.; Klein-Wolt, M.; Bentum, Marinus Jan; Rajan, R.T.; Rajan, Raj; Wijnholds, M.; Arts, M.; van 't Klooster, K.; Beliën, F.

    2010-01-01

    The frequency band below 30 MHz is one of the last unexplored bands in radio astronomy. This band is well suited for studying the early cosmos at high hydrogen redshifts, the so-called dark ages, extragalactic surveys, (extra) solar planetary bursts, and high energy particle physics. In addition,

  5. Root system topology and diameter distribution of species from habitats differing in inundation frequency

    NARCIS (Netherlands)

    Bouma, T.J.; Nielsen, K.F.; Van Hal, J.; Koutstaal, B.P.

    2001-01-01

    1. We compared the root systems of seven halophytic species that occur at different elevations on a salt marsh, in order to (i) test the hypothesis that variations in root system architecture reflect adaptation to inundation frequency or nitrogen limitation, and (ii) verify the theoretically

  6. Orbiting low frequency antennas for radio astronomy(OLFAR): Distributing signal processing

    NARCIS (Netherlands)

    Rajan, Raj; Rajan, R.T.; Budianu, A.; Engelen, Steven; van der Veen, Alle-Jan; Bentum, Marinus Jan; Boonstra, Albert Jan; Verhoeven, Chris

    2011-01-01

    Recently, new and interesting science drivers have emerged in the ultra low frequency range of 0.3-30 MHz ranging from the epoch of re-ionization, exo-planets, ultra-high energy cosmic rays and studies of the astronomical dark ages. However at these wavelengths, ground based observations are

  7. Improving ecological risk assessment by including bioavailability into species sensitivity distributions: An example for plants exposed to nickel in soil

    Energy Technology Data Exchange (ETDEWEB)

    Semenzin, Elena [Consorzio Venezia Ricerche, c/o VEGApark, Via della Liberta 5-12, 30175 Marghera-Venice (Italy)]. E-mail: semenzin.cvr@vegapark.ve.it; Temminghoff, Erwin J.M. [Wageningen University, Department of Environmental Science, Subdepartment of Soil Quality, PO Box 8005, 6700 EC Wageningen (Netherlands)]. E-mail: erwin.temminghoff@wur.nl; Marcomini, Antonio [Ca' Foscari University of Venice, Department of Environmental Sciences, Santa Marta - Dorsoduro 2137, 30121 Venice (Italy)]. E-mail: marcom@unive.it

    2007-07-15

    The variability of species sensitivity distribution (SSD) due to contaminant bioavailability in soil was explored by using nickel as metal of concern. SSDs of toxicity test results of Avena sativa L. originating from different soils and expressed as total content and available (0.01 M CaCl{sub 2}) extractable concentration were compared to SSDs for terrestrial plants derived from literature toxicity data. Also the 'free' nickel (Ni{sup 2+}) concentration was calculated and compared. The results demonstrated that SSDs based on total nickel content highly depend on the experimental conditions set up for toxicity testing (i.e. selected soil and pH value) and thus on metal bioavailability in soil, resulting in an unacceptable uncertainty for ecological risk estimation. The use in SSDs of plant toxicity data expressed as 0.01 M CaCl{sub 2} extractable metal strongly reduced the uncertainty in the SSD curve and thus can improve the ERA procedure remarkably by taking bioavailability into account. - The use of bioavailability toxicity data can improve species sensitivity distribution (SSD) curves and thus ecological risk assessment (ERA)

  8. Predicting species distribution and abundance responses to climate change: why it is essential to include biotic interactions across trophic levels.

    Science.gov (United States)

    Van der Putten, Wim H; Macel, Mirka; Visser, Marcel E

    2010-07-12

    Current predictions on species responses to climate change strongly rely on projecting altered environmental conditions on species distributions. However, it is increasingly acknowledged that climate change also influences species interactions. We review and synthesize literature information on biotic interactions and use it to argue that the abundance of species and the direction of selection during climate change vary depending on how their trophic interactions become disrupted. Plant abundance can be controlled by aboveground and belowground multitrophic level interactions with herbivores, pathogens, symbionts and their enemies. We discuss how these interactions may alter during climate change and the resulting species range shifts. We suggest conceptual analogies between species responses to climate warming and exotic species introduced in new ranges. There are also important differences: the herbivores, pathogens and mutualistic symbionts of range-expanding species and their enemies may co-migrate, and the continuous gene flow under climate warming can make adaptation in the expansion zone of range expanders different from that of cross-continental exotic species. We conclude that under climate change, results of altered species interactions may vary, ranging from species becoming rare to disproportionately abundant. Taking these possibilities into account will provide a new perspective on predicting species distribution under climate change.

  9. The contribution of local distribution substations and associated area distribution system to personal exposure to power frequency magnetic fields.

    Science.gov (United States)

    Grainger, P; Preece, A W

    2000-12-01

    A number of epidemiological studies has shown a significant correlation between wire coding, magnetic fields and childhood cancer, although a more recent study has not [McBride et al. (1999) Am. J. Epidemiol. 149 (9), 831-842]. In the UK there is currently no equivalent to wire-codes and there is some uncertainty about the extent to which the UK medium-voltage electricity distribution systems contribute to personal exposure and how this compares with US overhead supply systems. Studies on four different area types were carried out to measure magnetic field intensities from typical electricity supply utility substations and cabling in the vicinity of domestic housing. Typically at distances of two metres from the substations mean magnetic field intensities were 20 nano teslas (nT) or less, increasing to 0.98 microT or less at the closest public access point. The mean magnetic field exposure level sampled around the four main test areas varied between 0.012 and 0.27 microT increasing to 0.30-0.80 microT at road junctions.

  10. Low-frequency analog signal distribution on digital photonic networks by optical delta-sigma modulation

    Science.gov (United States)

    Kanno, Atsushi; Kawanishi, Tetsuya

    2013-12-01

    We propose a delta-sigma modulation scheme for low- and medium-frequency signal transmission in a digital photonic network system. A 10-Gb/s-class optical transceiver with a delta-sigma modulator utilized as a high-speed analog-to-digital converter (ADC) provides a binary optical signal. On the signal reception side, a low-cost and slow-speed photonic receiver directly converts the binary signal into an analog signal at frequencies from several hundreds of kilohertz several tens of megahertz. Further, by using a clock and data recovery circuit at the receiver to reduce jitters, the single-sideband phase noise of the generated signals can be significantly reduced.

  11. Parallelizing Serial Code for a Distributed Processing Environment with an Application to High Frequency Electromagnetic Scattering

    Science.gov (United States)

    1991-12-01

    build and are not always an accurate reproduction of the final design. Field measurements, on the other hand , can be expensive or extremely difficult to...on the other hand , can be quite pronounced at frequencies typically used by radars (2 - 16 GJlz). The only contribution from diffraction in a...corresponding element in the controlling variable as each) {contribution to the partial strenght is calculated) 6(Vi : 0 < i < vol-points :: D(V j : 0 < j

  12. Altered Frequency Distribution in the Electroencephalogram is Correlated to the Analgesic Effect of Remifentanil

    DEFF Research Database (Denmark)

    Graversen, Carina; Malver, Lasse P; Kurita, Geana P

    2015-01-01

    Opioids alter resting state brain oscillations by multiple and complex factors, which are still to be elucidated. To increase our knowledge, multi-channel electroencephalography (EEG) was subjected to multivariate pattern analysis (MVPA), to identify the most descriptive frequency bands and scalp...... remifentanil treatment. As the EEG alterations were correlated to the analgesic effect, the approach may prove to be a novel methodology for monitoring individual efficacy to opioids....

  13. Experimental and numerical assessment of low-frequency current distributions from UMTS and GSM mobile phones.

    Science.gov (United States)

    Gosselin, Marie-Christine; Kühn, Sven; Kuster, Niels

    2013-12-07

    The evaluation of the exposure from mobile communication devices requires consideration of electromagnetic fields (EMFs) over a broad frequency range from dc to GHz. Mobile phones in operation have prominent spectral components in the low-frequency (LF) and radio-frequency (RF) ranges. While the exposure to RF fields from mobile phones has been comprehensively assessed in the past, the LF fields have received much less attention. In this study, LF fields from mobile phones are assessed experimentally and numerically for the global system for mobile (GSM) and universal mobile telecommunications system (UMTS) communication systems and conclusions about the global (LF and RF) EMF exposure from both systems are drawn. From the measurements of the time-domain magnetic fields, it was found that the contribution from the audio signal at a normal speech level, i.e., -16 dBm0, is the same order of magnitude as the fields induced by the current bursts generated from the implementation of the GSM communication system at maximum RF output level. The B-field induced by currents in phones using the UMTS is two orders of magnitude lower than that induced by GSM. Knowing that the RF exposure from the UMTS is also two orders of magnitude lower than from GSM, it is now possible to state that there is an overall reduction of the exposure from this communication system.

  14. Experimental and numerical assessment of low-frequency current distributions from UMTS and GSM mobile phones

    International Nuclear Information System (INIS)

    Gosselin, Marie-Christine; Kühn, Sven; Kuster, Niels

    2013-01-01

    The evaluation of the exposure from mobile communication devices requires consideration of electromagnetic fields (EMFs) over a broad frequency range from dc to GHz. Mobile phones in operation have prominent spectral components in the low-frequency (LF) and radio-frequency (RF) ranges. While the exposure to RF fields from mobile phones has been comprehensively assessed in the past, the LF fields have received much less attention. In this study, LF fields from mobile phones are assessed experimentally and numerically for the global system for mobile (GSM) and universal mobile telecommunications system (UMTS) communication systems and conclusions about the global (LF and RF) EMF exposure from both systems are drawn. From the measurements of the time-domain magnetic fields, it was found that the contribution from the audio signal at a normal speech level, i.e., −16 dBm0, is the same order of magnitude as the fields induced by the current bursts generated from the implementation of the GSM communication system at maximum RF output level. The B-field induced by currents in phones using the UMTS is two orders of magnitude lower than that induced by GSM. Knowing that the RF exposure from the UMTS is also two orders of magnitude lower than from GSM, it is now possible to state that there is an overall reduction of the exposure from this communication system. (paper)

  15. Experimental and numerical assessment of low-frequency current distributions from UMTS and GSM mobile phones

    Science.gov (United States)

    Gosselin, Marie-Christine; Kühn, Sven; Kuster, Niels

    2013-12-01

    The evaluation of the exposure from mobile communication devices requires consideration of electromagnetic fields (EMFs) over a broad frequency range from dc to GHz. Mobile phones in operation have prominent spectral components in the low-frequency (LF) and radio-frequency (RF) ranges. While the exposure to RF fields from mobile phones has been comprehensively assessed in the past, the LF fields have received much less attention. In this study, LF fields from mobile phones are assessed experimentally and numerically for the global system for mobile (GSM) and universal mobile telecommunications system (UMTS) communication systems and conclusions about the global (LF and RF) EMF exposure from both systems are drawn. From the measurements of the time-domain magnetic fields, it was found that the contribution from the audio signal at a normal speech level, i.e., -16 dBm0, is the same order of magnitude as the fields induced by the current bursts generated from the implementation of the GSM communication system at maximum RF output level. The B-field induced by currents in phones using the UMTS is two orders of magnitude lower than that induced by GSM. Knowing that the RF exposure from the UMTS is also two orders of magnitude lower than from GSM, it is now possible to state that there is an overall reduction of the exposure from this communication system.

  16. Frequency Distribution of Hearing Disorders Among the Student of Public Elementary school in EslamAbad Gharb

    Directory of Open Access Journals (Sweden)

    Dr. Abdollah Mousavi

    2000-05-01

    Full Text Available Objects Determining the frequency distribution of hearing disorders among the student of public elementary school by Otoscopy, Puretone Audiometry, impedance Audiometry and questionnaires. Methods and Materials: This study was can-led out in a cross - sectional descriptive survey - on 1000 students (500 girls and 500 boys among the student of primary school of EslamAhad Gharh, academic year 1376-77 Results: 1- Otoscopy examination; abnormal conditions of external ear canal was found in 13.65% of cases; mostly impacted ceruman (13.3%. Abnormal conditions of external ear canal was more prevalent in girls than boys and the difference was statistically meaningful in the right (P V=0 .012 and left (PV=0.043 ear. Abnormal tympanic membrane was seen in 6.75% of cases; mostly retraction (295%. "n2- Impedance Audiometry: 11.05% abnormal tympanograms were observed, mostly type C (4.1%. 3- Pure Tone Audiometry: An overall 9.7% hearing loss was found in this population including 3.5% bilateral and 6.2% unilateral hearing loss. 4.15% of population suffered from SNHL observed mostly in boys and conductive. Hearing loss mostly in girls and the difference was statistically meaning in the left ear (PV=0.03. (l.e 0.6% were in need of rehabilitation services. Family background showed on effects on the hearing disorders. Only 11. 4% of parents, 13.4% of teachers and 14.4% of afflicted students were aware of the problem.

  17. The Impact Crater Size-Frequency Distribution on Pluto Follows a Truncated Pareto Distribution: Results from a First Data Set Based on the Recent New Horizons' Flyby

    Directory of Open Access Journals (Sweden)

    Zaninetti L.

    2016-01-01

    Full Text Available Recently it could be shown (Scholkmann, Prog. in Phys. , 2016, v. 12(1, 26-29 that the impact crater size-frequency distribution of Pluto (based on an analysis of first images obtained by the recent New Horizons’ flyby follows a power law (α =2.4926±0.3309 in the interval of diameter ( D values ranging from 3.75±1.14 km to the largest deter- mined value of 37.77 km. A reanalysis of this data set revealed that the whole crater SFD (i.e., with values in the interval of 1.2–37.7 km can be described by a truncated Pareto distribution.

  18. Voltage and frequency control in the Islanded portion of the CIGRE Low Voltage distribution network

    DEFF Research Database (Denmark)

    Mustafa, Ghullam; Bak, Claus Leth; Buriro, Ehsan Ali

    2017-01-01

    Islanding is a condition where a portion of the power network comprising of the loads and Distributed Generation units is isolated from the rest of the power grid and forms a Micro Grid. In this condition, it becomes essential for the islanded MG to operate in a stable and controlled manner by pr...

  19. 17 CFR 270.19b-1 - Frequency of distribution of capital gains.

    Science.gov (United States)

    2010-04-01

    ... trust may distribute capital gain dividends received from a “regulated investment company” within a reasonable time after receipt. (c) The provisions of this rule shall not apply to a unit investment trust (hereinafter referred to as the “Trust”) engaged exclusively in the business of investing in eligible trust...

  20. Poroviscoelastic finite element model including continuous fiber distribution for the simulation of nanoindentation tests on articular cartilage.

    Science.gov (United States)

    Taffetani, M; Griebel, M; Gastaldi, D; Klisch, S M; Vena, P

    2014-04-01

    Articular cartilage is a soft hydrated tissue that facilitates proper load transfer in diarthroidal joints. The mechanical properties of articular cartilage derive from its structural and hierarchical organization that, at the micrometric length scale, encompasses three main components: a network of insoluble collagen fibrils, negatively charged macromolecules and a porous extracellular matrix. In this work, a constituent-based constitutive model for the simulation of nanoindentation tests on articular cartilage is presented: it accounts for the multi-constituent, non-linear, porous, and viscous aspects of articular cartilage mechanics. In order to reproduce the articular cartilage response under different loading conditions, the model considers a continuous distribution of collagen fibril orientation, swelling, and depth-dependent mechanical properties. The model's parameters are obtained by fitting published experimental data for the time-dependent response in a stress relaxation unconfined compression test on adult bovine articular cartilage. Then, model validation is obtained by simulating three independent experimental tests: (i) the time-dependent response in a stress relaxation confined compression test, (ii) the drained response of a flat punch indentation test and (iii) the depth-dependence of effective Poisson's ratio in a unconfined compression test. Finally, the validated constitutive model has been used to simulate multiload spherical nanoindentation creep tests. Upon accounting for strain-dependent tissue permeability and intrinsic viscoelastic properties of the collagen network, the model accurately fits the drained and undrained curves and time-dependent creep response. The results show that depth-dependent tissue properties and glycosaminoglycan-induced tissue swelling should be accounted for when simulating indentation experiments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Frequency distribution of virulence factors in uropathogenic Escherichia coli isolated from Kermanshah in 2011-2012.

    Science.gov (United States)

    Mohajeri, Parviz; Khademi, Hosna; Ebrahimi, Roya; Farahani, Abbas; Rezaei, Mansour

    2014-07-01

    Uropathogenic Escherichia coli (UPEC) can cause urinary tract infection (UTI). To prevent urine flow lavage, UPEC has acquired several virulence factors called adhesins. These adhesins are expressed and controlled by different genes. This study was aimed to determine some of the most important genes that control virulence factors of UPEC (pyelonephritis associated pili [pap], S fimbrial adhesion [sfa] and A fimbrial adhesion [afa] genes), which code for adhesins and phenotypic factors. In total, 205 UPEC isolates from in- and out-patients with UTI were obtained. Polymerase chain reaction was used for gene amplification. One drop of bacterial suspension, one of red blood cells and one of peripheral blood smear were mixed for hemagglutination (HA). Formation of a clump was considered to be positive. Bacteria were grown on blood agar to determine hemolysis. Surface hydrophobicity was determined using the SAT test. Frequencies of pap, afa and sfa were 42 (20.5%), 17 (8.3%) and 44 (21.5%), respectively. Frequencies of HA, hemolysis and hydrophobicity were 138 (67.3%), 56 (27.3%) and 39 (19%), respectively. Among HA-positive bacteria, 103 (74.6%) were mannose resistant. Our results highlight higher frequency of HA than that of other virulence factors, indicating a crucial role of this virulence factor in UPEC. We concluded that major differences exist in the prevalence of virulence factors among different UPEC isolated from different countries. The association observed between pathogenicity and virulence factors may promote UPEC survival and growth within the urinary tract. Detecting these genes as the primary controllers of UPEC virulence factors may aid in better management of related infections.

  2. The neurotopography of written word production: an fMRI investigation of the distribution of sensitivity to length and frequency.

    Science.gov (United States)

    Rapp, Brenda; Dufor, Olivier

    2011-12-01

    This research is directed at charting the neurotopography of the component processes of the spelling system by using fMRI to identify the neural substrates that are sensitive to the factors of lexical frequency and word length. In spelling, word frequency effects index orthographic long-term memory whereas length effects, as measured by the number of letters, index orthographic working memory (grapheme buffering). Using the task of spelling to dictation in the scanner, we found a highly differentiated neural distribution of sensitivity to the factors of length and lexical frequency, with areas exhibiting sensitivity to length but not frequency and vice versa. In addition, a direct comparison with the results of a previous study [Rapp, B., & Lipka, K. The literate brain: The relationship between spelling and reading. Journal of Cognitive Neuroscience, 23, 1180-1197, 2011] that used a very different spelling task yielded a converging pattern of findings regarding the neural substrates of the central components of spelling. Also, with regard to relationship between reading and spelling, we replicated previous functional neuroimaging studies that have shown overlapping regions of activation in the left posterior inferior frontal gyrus and midfusiform gyrus for word reading and spelling.

  3. Experimental measurement of the electron energy distribution function in the radio frequency electron cyclotron resonance inductive discharge

    International Nuclear Information System (INIS)

    Chung, ChinWook; Kim, S.S.; Chang, H.Y.

    2004-01-01

    Recently, the existence of electron cyclotron resonance (ECR) in a weakly magnetized inductively coupled plasma (MICP) has been evidenced [ChinWook Chung et al., Phys. Rev. Lett. 80, 095002 (2002)]. The distinctive feature of the ECR effect in the MICP is efficacious heating of low-energy electrons. In the present paper, electron heating characteristics in the MICP have been investigated by observing electron energy distribution function dependencies on various external parameters such as gas pressure, driving frequency, and rf power (electron density). It is found that the ECR effect on electron heating becomes enhanced with decreasing pressure or increasing driving frequency. The ECR heating becomes weak at high rf power due to the electron-electron collisions

  4. Investigation of the interpolation method to improve the distributed strain measurement accuracy in optical frequency domain reflectometry systems.

    Science.gov (United States)

    Cui, Jiwen; Zhao, Shiyuan; Yang, Di; Ding, Zhenyang

    2018-02-20

    We use a spectrum interpolation technique to improve the distributed strain measurement accuracy in a Rayleigh-scatter-based optical frequency domain reflectometry sensing system. We demonstrate that strain accuracy is not limited by the "uncertainty principle" that exists in the time-frequency analysis. Different interpolation methods are investigated and used to improve the accuracy of peak position of the cross-correlation and, therefore, improve the accuracy of the strain. Interpolation implemented by padding zeros on one side of the windowed data in the spatial domain, before the inverse fast Fourier transform, is found to have the best accuracy. Using this method, the strain accuracy and resolution are both improved without decreasing the spatial resolution. The strain of 3 μϵ within the spatial resolution of 1 cm at the position of 21.4 m is distinguished, and the measurement uncertainty is 3.3 μϵ.

  5. Self-induced frequency scanning and distributed Bragg reflection in semiconductor lasers with phase-conjugate feedback

    Energy Technology Data Exchange (ETDEWEB)

    Cronin-Golomb; Yariv

    1986-07-01

    A GaA1As semiconductor laser with feedback from a barium titanate photorefractive ring passive phase-conjugate mirror can be made to perform repeating or nonrepeating frequency scans over a 10-nm range toward either the blue or the red. The direction of scanning and whether the scans repeat may be controlled by adjusting the overlap of the interaction beams in the crystal. This overlap region may be adjusted so that the diode frequency spectrum, originally occupying about 10 longitudinal modes, scans and narrows as the conjugate signal builds up, coming to rest often in one, but sometimes two or three, longitudinal modes as a result of self-generated distributed-feedback effects. Also reported similar effects caused by feedback from the total-internal-reflection passive phase-conjugate mirror. The alignment-control mechanism of the ring mirror is, however, not available in this case.

  6. Self-induced frequency scanning and distributed Bragg reflection in semiconductor lasers with phase-conjugate feedback

    Energy Technology Data Exchange (ETDEWEB)

    Cronin-Golomb, M.; Yariv, A.

    1986-07-01

    A GaAlAs semiconductor laser with feedback from a barium titanate photorefractive ring passive phase-conjugate mirror can be made to perform repeating or nonrepeating frequency scans over a 10-nm range toward either the blue or the red. The direction of scanning and whether the scans repeat may be controlled by adjusting the overlap of the interaction beams in the crystal. This overlap region may be adjusted so that the diode frequency spectrum, originally occupying about 10 longitudinal modes, scans and narrows as the conjugate signal builds up, coming to rest often in one, but sometimes two or three, longitudinal modes as a result of self-generated distributed-feedback effects. We also report similar effects caused by feedback from the total-internal-reflection passive phase-conjugate mirror. The alignment-control mechanism of the ring mirror is, however, not available in this case.

  7. Self-induced frequency scanning and distributed bragg reflection in semiconductor lasers with phase-conjugate feedback

    Science.gov (United States)

    Cronin-Golomb, Mark; Yariv, Amnon

    1986-07-01

    A GaAlAs semiconductor laser with feedback from a barium titanate photorefractive ring passive phase-conjugate mirror can be made to perform repeating or nonrepeating frequency scans over a 10-nm range toward either the blue or the red. The direction of scanning and whether the scans repeat may be controlled by adjusting the overlap of the interaction beams in the crystal. This overlap region may be adjusted so that the diode frequency spectrum, originally occupying about 10 longitudinal modes, scans and narrows as the conjugate signal builds up, coming to rest often in one, but sometimes two or three, longitudinal modes as a result of self-generated distributed-feedback effects. We also report similar effects caused by feedback from the total-internal-reflection passive phase-conjugate mirror. The alignment-control mechanism of the ring mirror is, however, not available in this case.

  8. I-BIEM calculations of the frequency dispersion and AC current distribution at disk and ring-disk electrodes

    Science.gov (United States)

    Cahan, Boris D.

    1991-01-01

    The Iterative Boundary Integral Equation Method (I-BIEM) has been applied to the problem of frequency dispersion at a disk electrode in a finite geometry. The I-BIEM permits the direct evaluation of the AC potential (a complex variable) using complex boundary conditions. The point spacing was made highly nonuniform, to give extremely high resolution in those regions where the variables change most rapidly, i.e., in the vicinity of the edge of the disk. Results are analyzed with respect to IR correction, equipotential surfaces, and reference electrode placement. The current distribution is also examined for a ring-disk configuration, with the ring and the disk at the same AC potential. It is shown that the apparent impedance of the disk is inductive at higher frequencies. The results are compared to analytic calculations from the literature, and usually agree to better than 0.001 percent.

  9. Rabi-Bloch oscillations in spatially distributed systems: Temporal dynamics and frequency spectra

    Science.gov (United States)

    Levie, Ilay; Kastner, Raphael; Slepyan, Gregory

    2017-10-01

    We consider one-dimensional chains of two-level quantum systems coupled via tunneling. The chain is driven by the superposition of dc and ac fields in the strong coupling regime. Based on the fundamental principles of electrodynamics and quantum theory, we have developed a generalized model of quantum dynamics for such interactions, free of rotating-wave approximation. The system of equations of motion was studied numerically. We analyzed the dynamics and spectra of the inversion density, dipole current density, and tunneling current density. In the case of resonant interaction with the ac component, the particle dynamics exhibits itself in the oscillatory regime, which may be interpreted as a combination of Rabi and Bloch oscillations with their strong mutual influence. Such scenario for an obliquely incident ac field dramatically differs from the individual picture of both types of oscillations due to the interactions. This effect is counterintuitive because of the existence of markedly different frequency ranges for such two types of oscillations. These dynamics manifest themselves in multiline spectra in different combinations of Rabi and Bloch frequencies. The effect is promising as a framework of a new type of spectroscopy in nanoelectronics and electrical control of nanodevices.

  10. Allele frequency distribution for 15 autosomal STR loci in Afridi Pathan population of Uttar Pradesh, India.

    Science.gov (United States)

    Noor, Sabahat; Ali, Shahnaz; Eaaswarkhanth, Muthukrishnan; Haque, Ikramul

    2009-11-01

    Allele frequencies of the 15 autosomal short tandem repeat (STR) loci D8S1179, D21S11, D7S820, CSF1PO D19S433, vWA, TPOX, D18S51, D3S1358, THO1, D13S317, D16S539, D2S1338, D5S818 and FGA were determined in Afridi Pathan population of Uttar Pradesh, India. All the 15 STR loci studied were found to be highly polymorphic with respect to observed heterozygosity values. Adherence to the expectations of the Hardy-Weinberg equilibrium (HWE) was confirmed for all the loci with an exception of TPOX and FGA. The allele 12 in CSF1PO was found to be most frequent. The power of discrimination was found to be high ranging from a minimum of 0.858 for the locus CSFIPO to maximum of 0.962 for the locus FGA, thereby facilitating the validation and efficiency of these STR markers in human identification. Population differentiation test between the studied and neighboring populations revealed significant differences at several loci suggesting the endogamous nature of the studied population. To the best of our knowledge, Afridi Pathan population has not been explored genetically for generating forensic data on STR markers. Therefore, STR allele frequency data of this unique population is a valuable contribution to the existing DNA database on Indian populations.

  11. Reconsidering the smart metering data collection frequency for distribution state estimation

    OpenAIRE

    Chen, Qipeng; Kaleshi, Dritan; Armour, Simon; Fan, Zhong

    2015-01-01

    The current UK Smart Metering Technical Specification requires smart meter readings to be collected once a day, primarily to support accurate billing without violating users' privacy. In this paper we consider the use of Smart Metering data for Distribution State Estimation (DSE), and compare the effectiveness of daily data collection strategy with a more frequent, half-hourly SM data collection strategy. We first assess the suitability of using the data for load forecasting at Low Voltage (L...

  12. Category effects on stimulus estimation: Shifting and skewed frequency distributions-A reexamination.

    Science.gov (United States)

    Duffy, Sean; Smith, John

    2017-10-18

    Duffy, Huttenlocher, Hedges, and Crawford (Psychonomic Bulletin & Review, 17(2), 224-230, 2010) report on experiments where participants estimate the lengths of lines. These studies were designed to test the category adjustment model (CAM), a Bayesian model of judgments. The authors report that their analysis provides evidence consistent with CAM: that there is a bias toward the running mean and not recent stimuli. We reexamine their data. First, we attempt to replicate their analysis, and we obtain different results. Second, we conduct a different statistical analysis. We find significant recency effects, and we identify several specifications where the running mean is not significantly related to judgment. Third, we conduct tests of auxiliary predictions of CAM. We do not find evidence that the bias toward the mean increases with exposure to the distribution. We also do not find that responses longer than the maximum of the distribution or shorter than the minimum become less likely with greater exposure to the distribution. Fourth, we produce a simulated dataset that is consistent with key features of CAM, and our methods correctly identify it as consistent with CAM. We conclude that the Duffy et al. (2010) dataset is not consistent with CAM. We also discuss how conventions in psychology do not sufficiently reduce the likelihood of these mistakes in future research. We hope that the methods that we employ will be used to evaluate other datasets.

  13. Frequency of legionella contamination in conditional & water distribution systems of Tehran hospitals

    Directory of Open Access Journals (Sweden)

    Davod Esmaieli

    2008-09-01

    Full Text Available Background: Legionella species are ubiquitous in natural aquatic environments, capable of existing in waters with varied temperatures, PH levels, and nutrient and oxygen contents. Of 49 known legionella species, 20 species have been linked to pneumonia in humans. Contamination by legionella has occurred in the distribution systems of many hospitals. Aerosol-generating systems such as faucets, showerheads, cooling towers, and nebulizers are responsible for their transmission from water to air. Methods: A total of 113 water samples were gathered from different wards of 32 hospitals in different geographical regions of Tehran city. These samples were concentrated by filtration, treated with the acid and temperature buffers, and isolated on a BCYE agar culture medium. Results: A total of 22 hospitals out of 33 (26.5% were contaminated by legionella species, and 30 samples (26.5% out of 113 were positive. Chlorine concentration and pH level of the water samples were 0.18-2.2 mg/l and 6.6-7.6, respectively. Conclusion: The high rate of waste water contamination in Tehran hospitals with Legionella indicates the resistance of this microorganism to chlorine and other disinfectants, or inadequate disinfection process, representing the insufficiency of the current decontamination of hospital water distribution system. Thus identifying legionella species and their controlling in water distribution system of hospitals is of great importance.

  14. Allele frequency distribution of D8S592 (STR) and PDGFA (VNTR) among five endogamous population groups of India.

    Science.gov (United States)

    Ahmad, Shazia; Seshadri, M

    2004-07-01

    Allele frequency distribution have been analyzed at D8S592 (short tandem repeat) and PDGFA (variable number of tandem repeat) among five distinct endogamous groups of India namely Ezhavas, Nayers, Arayas, Vishwakarma and Muslims. Muslims are religio-ethnic group while other populations mentioned above belong to distinct section of Hindu religion. All these populations are from Kollam district of Kerala in Southern India and speak Malayalam, an Indo-Dravidian language. A total of 228 for D8S592 and 212 for PDGFA loci, random, healthy individuals were analyzed.

  15. Observation and simulation of space-charge effects in a radio-frequency photoinjector using a transverse multibeamlet distribution

    Directory of Open Access Journals (Sweden)

    M. Rihaoui

    2009-12-01

    Full Text Available We report on an experimental study of space-charge effects in a radio-frequency (rf photoinjector. A 5 MeV electron bunch, consisting of a number of beamlets separated transversely, was generated in an rf photocathode gun and propagated in the succeeding drift space. The collective interaction of these beamlets was studied for different experimental conditions. The experiment allowed the exploration of space-charge effects and its comparison with 3D particle-in-cell simulations. Our observations also suggest the possible use of a multibeam configuration to tailor the transverse distribution of an electron beam.

  16. Using radio frequency and ultrasonic antennas for inspecting pin-type insulators on medium-voltage overhead distribution lines

    Directory of Open Access Journals (Sweden)

    Cícero Lefort Borges

    2013-05-01

    Full Text Available This paper summarises the activities undertaken when using antennas (ultrasound and radiofrequency for identifying insulators in pre-failure state by detecting the noise emitted by the distribution line and correlating this with these insulators (porcelain pin type dielectric breakdown. This has led to developing low-cost maintenance procedures and providing support and criteria for engineer-ing decisions regarding replacing these insulators. The technique used two detectors; a radio frequency detector was used in a first investigation of a particular distribution line, set to 40 MHz and installed on the roof of a moving vehicle. The ultrasound detector was used for inspecting (phases A, B, C each structure (pole selected. Atmospheric conditions had no influence on defining pre-failure insulators (pin type based on the noise detection technique. Pin type insulators emitting noise should be replaced since measurement was made from the ground and near the base of the post.

  17. Frequency distribution of zinc in leaves with and without zinc-deficiency symptoms, all collected from a single orange tree

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, A. (Univ. of Caifornia, Los Angeles); Alexander, G.V.; Kinnear, J.; Procopiou, J.; Haritou-Andriotaki, A.; Papanicolaou, X.

    1982-07-01

    Leaves with zinc-deficiency symptoms had a lower Zn concentration than corresponding leaves without symptoms and of the same age from the same orange (Citrus senensis L.) tree on sour orange (C. aurantium L.) rootstock grown in Rhodes, Greece. There was considerable overlap, however, with the frequency distribution of each group approximating a normal curve. But both kinds of leaves combined showed a more normal distribution. Some leaves with symptoms had higher zinc concentrations than some without symptoms. There was a threefold range in Zn concentration for each group of leaves. Zinc-deficient leaves had less phosphorus, calcium, and manganese and more iron, aluminum, silicon, and titanium (the so-called dust elements) than did leaves with no deficiency symptoms. Some of these elements gave normal curves for both Zn-deficient and non-Zn-deficient leaves.

  18. Use of critical pathway models and log-normal frequency distributions for siting nuclear facilities

    International Nuclear Information System (INIS)

    Waite, D.A.; Denham, D.H.

    1975-01-01

    The advantages and disadvantages of potential sites for nuclear facilities are evaluated through the use of environmental pathway and log-normal distribution analysis. Environmental considerations of nuclear facility siting are necessarily geared to the identification of media believed to be sifnificant in terms of dose to man or to be potential centres for long-term accumulation of contaminants. To aid in meeting the scope and purpose of this identification, an exposure pathway diagram must be developed. This type of diagram helps to locate pertinent environmental media, points of expected long-term contaminant accumulation, and points of population/contaminant interface for both radioactive and non-radioactive contaminants. Confirmation of facility siting conclusions drawn from pathway considerations must usually be derived from an investigatory environmental surveillance programme. Battelle's experience with environmental surveillance data interpretation using log-normal techniques indicates that this distribution has much to offer in the planning, execution and analysis phases of such a programme. How these basic principles apply to the actual siting of a nuclear facility is demonstrated for a centrifuge-type uranium enrichment facility as an example. A model facility is examined to the extent of available data in terms of potential contaminants and facility general environmental needs. A critical exposure pathway diagram is developed to the point of prescribing the characteristics of an optimum site for such a facility. Possible necessary deviations from climatic constraints are reviewed and reconciled with conclusions drawn from the exposure pathway analysis. Details of log-normal distribution analysis techniques are presented, with examples of environmental surveillance data to illustrate data manipulation techniques and interpretation procedures as they affect the investigatory environmental surveillance programme. Appropriate consideration is given these

  19. Palomar-Leiden minor planets - Proper elements, frequency distributions, belt boundaries, and family memberships

    Science.gov (United States)

    Williams, J. G.; Hierath, J. E.

    1987-01-01

    Tabulations are presented for the proper elements of 1227 higher accuracy orbits of faint minor planets encompassing earth and deep Mars crossers, Trojans, and Hildas. The distribution of the closest approach distance to Mars drops off sharply near zero, while that for Jupiter vanishes near 1.1 AU; it is suggested that Mars and Jupiter have caused these boundaries, so that the asteroid belt must have been larger early in the solar system's history. Some 3.5 percent of the sample, primarily shallow crossers, can impact Mars; the fortuitous alignments required for impact occur with near-simultaneity for these objects, so that they will episodically bombard Mars.

  20. In-plane modal frequencies and mode shapes of two stay cables interconnected by uniformly distributed cross-ties

    Science.gov (United States)

    Jing, Haiquan; He, Xuhui; Zou, Yunfeng; Wang, Hanfeng

    2018-03-01

    Stay cables are important load-bearing structural elements of cable-stayed bridges. Suppressing the large vibrations of the stay cables under the external excitations is of worldwide concern for the bridge engineers and researchers. Over the past decade, the use of crosstie has become one of the most practical and effective methods. Extensive research has led to a better understanding of the mechanics of cable networks, and the effects of different parameters, such as length ratio, mass-tension ratio, and segment ratio on the effectiveness of the crosstie have been investigated. In this study, uniformly distributed elastic crossties serve to replace the traditional single, or several cross-ties, aiming to delay "mode localization." A numerical method is developed by replacing the uniformly distributed, discrete elastic cross-tie model with an equivalent, continuously distributed, elastic cross-tie model in order to calculate the modal frequencies and mode shapes of the cable-crosstie system. The effectiveness of the proposed method is verified by comparing the elicited results with those obtained using the previous method. The uniformly distributed elastic cross-ties are shown to significantly delay "mode localization."

  1. High rhesus (Rh(D)) negative frequency and ethnic-group based ABO blood group distribution in Ethiopia.

    Science.gov (United States)

    Golassa, Lemu; Tsegaye, Arega; Erko, Berhanu; Mamo, Hassen

    2017-07-26

    Knowledge of the distribution of ABO-Rh(D) blood groups in a locality is vital for safe blood services. However, the distribution of these blood systems among Ethiopians in general is little explored. This study was, therefore, designed to determine the ABO-Rh(D) blood group distribution among patients attending Gambella hospital, southwestern Ethiopia. A cross-sectional study was conducted between November and December 2013 (N = 449). The patients were grouped into two broad categories. Those who originally moved from different parts of Ethiopia and currently residing in Gambella are named 'highlanders' (n = 211). The other group consisted of natives (Nilotics) to the locality (n = 238). ABO-Rh(D) blood groups were typed by agglutination, open-slide test method, using commercial antisera (Biotech laboratories Ltd, Ipswich, Suffolk, UK). Overall, majority of the participants (41.20%) had blood type 'O' followed by types 'A' (34.96%), 'B' (20.48%) and 'AB' (3.34%). However, blood type 'A' was the most frequent (44.07%) blood group among the 'highlanders' and 50.42% of Nilotic natives had type 'O'. The proportion of participants devoid of the Rh factor was 19.37%. While the ABO blood group distribution is similar to previous reports, the Rh(D) frequency is much higher than what was reported so far for Ethiopia and continental Africa.

  2. Assessment of landslide distribution map reliability in Niigata prefecture - Japan using frequency ratio approach

    Science.gov (United States)

    Rahardianto, Trias; Saputra, Aditya; Gomez, Christopher

    2017-07-01

    Research on landslide susceptibility has evolved rapidly over the few last decades thanks to the availability of large databases. Landslide research used to be focused on discreet events but the usage of large inventory dataset has become a central pillar of landslide susceptibility, hazard, and risk assessment. Indeed, extracting meaningful information from the large database is now at the forth of geoscientific research, following the big-data research trend. Indeed, the more comprehensive information of the past landslide available in a particular area is, the better the produced map will be, in order to support the effective decision making, planning, and engineering practice. The landslide inventory data which is freely accessible online gives an opportunity for many researchers and decision makers to prevent casualties and economic loss caused by future landslides. This data is advantageous especially for areas with poor landslide historical data. Since the construction criteria of landslide inventory map and its quality evaluation remain poorly defined, the assessment of open source landslide inventory map reliability is required. The present contribution aims to assess the reliability of open-source landslide inventory data based on the particular topographical setting of the observed area in Niigata prefecture, Japan. Geographic Information System (GIS) platform and statistical approach are applied to analyze the data. Frequency ratio method is utilized to model and assess the landslide map. The outcomes of the generated model showed unsatisfactory results with AUC value of 0.603 indicate the low prediction accuracy and unreliability of the model.

  3. Low Frequency Vibration Energy Harvester Using Spherical Permanent Magnet with Non-uniform Mass Distribution

    International Nuclear Information System (INIS)

    Choi, Y; Ju, S; Chae, S H; Jun, S; Park, S M; Lee, S; Ji, C-H; Lee, H W

    2013-01-01

    We present a non-resonant vibration energy harvesting device using springless spherical permanent magnet with non-uniform mass distribution as a proof mass. The magnet has its center-of-mass below the geometrical center, which generates a roly-poly-like motion in response to external vibrations. Two different types of magnet assemblies with different center-of-mass position have been fabricated and tested. Using the roly-poly-like magnets, proof-of-concept electromagnetic energy harvesters have been fabricated and tested. Moreover, effect of ferrofluid as a lubricant has been tested with the fabricated energy harvester. Maximum open-circuit voltage of 154.4mV and output power of 4.53μW have been obtained at 3g vibration at 12Hz with the fabricated device

  4. Global Frequency and Distribution of Lightning as Observed from Space by the Optical Transient Detector

    Science.gov (United States)

    Christian, Hugh J.; Blakeslee, Richard J.; Boccippio, Dennis J.; Boeck, William L.; Bucchler, Dennis E.; Driscoll, Kevin T.; Goodman, Steven J.; Hall, John M.; Koshak, William J.; Mach, Douglas M.; hide

    2002-01-01

    The Optical Transient Detector (OTD) is a space-based instrument specifically designed to detect and locate lightning discharges as it orbits the Earth. This instrument is a scientific payload on the MicroLab-1 satellite that was launched into a low-earth, 70 deg. inclination orbit in April 1995. Given the orbital trajectory of the satellite, most regions of the earth are observed by the OTD instrument more than 400 times during a one year period, and the average duration of each observation is 2 minutes. The OTD instrument optically detects lightning flashes that occur within its 1300x1300 sq km field-of-view during both day and night conditions. A statistical examination of OTD lightning data reveals that nearly 1.4 billion flashes occur annually over the entire earth. This annual flash count translates to an average of 44 +/- 5 lightning flashes (intracloud and cloud-to-ground combined) occurring around the globe every second, which is well below the traditional estimate of 100 flashes per second that was derived in 1925 from world thunder-day records. The range of uncertainty for the OTD global totals represents primarily the uncertainty (and variability) in the flash detection efficiency of the instrument. The OTD measurements have been used to construct lightning climatology maps that demonstrate the geographical and seasonal distribution of lightning activity for the globe. An analysis of this annual lightning distribution confirms that lightning occurs mainly over land areas, with an average land:ocean ratio of 10:1. A dominant Northern Hemisphere summer peak occurs in the annual cycle, and evidence is found for a tropically-driven semiannual cycle.

  5. Time-dependent electron kinetics in N[sub 2] and H[sub 2] for a wide range of the field frequency including electron-vibration superelastic collisions

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, J. (Centro de Electrodinamica da Universidade Tecnica de Lisboa, Instituto Superior Tecnico, 1096 Lisboa Codex (Portugal))

    1993-02-01

    Electron-energy distribution functions (EEDF), electron-transport parameters, and rate coefficients have been calculated by solving the time-dependent Boltzmann equation in weakly ionized plasmas in N[sub 2] and H[sub 2], for a wide range of the field frequency going from [omega][much lt][nu][sub [ital e

  6. Notes on distribution, conservation, and taxonomy OF birds from the Cape Verde Islands, including records of six species new to the archipelago

    NARCIS (Netherlands)

    Hazevoet, Cornelis J.

    1997-01-01

    Recent data on the distribution of birds in the Cape Verde Islands are presented, including records of six species new to the archipelago, viz. Pintail Anas acuta, Least Sandpiper Calidris minutilla, Snipe Gallinago gallinago, Red-rumped Swallow Hirundo daurica, African Sand Martin Riparia

  7. Age frequency distribution and revised stable isotope curves for New Zealand speleothems: palaeoclimatic implications

    Directory of Open Access Journals (Sweden)

    Williams Paul W.

    2010-07-01

    Full Text Available The occurrence of speleothems in New Zealand with reversed magnetism indicates that secondary calcite deposition in caves has occurred for more than 780 thousand years (ka. 394 uranium-series dates on 148 speleothems show that such deposition has taken place somewhere in the country with little interruption for more than 500 ka. A relative probability distribution of speleothem ages indicates that most growth occurred in mild, moist interglacial and interstadial intervals, a conclusion reinforced by comparing peaks and troughs in the distribution with time series curves of speleothem δ18O and δ13C values. The stable isotope time series were constructed using data from 15 speleothems from two different regions of the country. The greater the number of overlapping speleothem series (i.e. the greater the sample depth for any one region, the more confidence is justified in considering the stacked record to be representative of the region. Revising and extending earlier work, composite records are produced for central-west North Island (CWNI and north-west South Island (NWSI. Both demonstrate that over the last 15 ka the regions responded similarly to global climatic events, but that the North Island site was also influenced by the waxing and waning of regional subtropical marine influences that penetrated from the north but did not reach the higher latitudes of the South Island. Cooling marking the commencement of the last glacial maximum (LGM was evident from about 28 ka. There was a mid-LGM interstadial at 23-21.7 ka and Termination 1 occurred around 18.1 ka. The glacial-interglacial transition was marked by a series of negative excursions in δ18O that coincide with dated recessional moraines in South Island glaciers. A late glacial cooling event, the NZ Late Glacial Reversal, occurred from 13.4-11.2 ka and this was followed by an early Holocene optimum at 10.8 ka. Comparison of δ18O records from NWSI and EPICA DML ice-core shows climatic

  8. Frequency Distribution of Edentulous Posterior Mandibular Ridge Types using Cone Beam Computed Tomography in an Iranian Population

    Directory of Open Access Journals (Sweden)

    2016-07-01

    Full Text Available Introduction: The existing bone is regarded as an important criteria in dental implants. In this regard, the radiographic modality is of great significance in quantifying the remaining bone, and CBCT accurately represents height and width of the existing bone. Therefore, this study aimed to evaluate the frequency distribution of the edentulous posterior mandibular ridge types using cone beam computed tomography in an Iranian population. Methods: In this cross-sectional descriptive study, CBCT scans of 127 patients with full edentulous mandible with an average age of 61.15 were evaluated who referred to a radiology clinic in Tehran. The images were analyzed applying OnDemand3D application and bone height and width of each area were determined. To analyze the collected data, SPSS software (ver,17 was employed applying Fisher's exact test. Results: The ridges were classified in 4 different groups (A,B+,B-w,C-w. The frequency of ridge types A and B + in male and ridge types B-w and C-w in females were demonstrated to be higher. An increase in age led to a reduction in the frequency of type A and a rise in the frequency of type C-w. The mean bone height was higher in males in all areas. In addition, the mean bone width was higher in males in all areas except for the first molar area. Conclusions:  The study results indicated that as the age increases, the height of edentulous mandible reduces, while no significant relationship was detected between the bone width and aging. As a result, with aging the evolution of bone was held to be from type A to type C-W.

  9. Transient hepatic attenuation difference (THAD) in patients without neoplasm. Frequency, shape, distribution, and causes

    Energy Technology Data Exchange (ETDEWEB)

    Yamasaki, Michio; Furukawa, Akira; Murata, Kiyoshi; Morita, Rikushi [Shiga Univ. of Medical Science, Otsu (Japan)

    1999-03-01

    Transient hepatic attenuation difference (THAD) is a valuable finding in detecting hypervascular lesions. However, similar findings are also observed in patients even without known hepatic diseases. We elucidate the characteristic findings and the causes of THAD in patients without hepatic neoplasm in this article. Dual-phased contrast-enhanced CT studies performed in 450 patients were reviewed, and THAD was observed in 42 (9.3%). THAD was linear or wedge-shaped and was seen contiguous to the liver surface with a relatively obscure margin in 40 of the 42 cases. The most common cause of THAD was chronic cholecystitis followed by previous biliary surgery. THAD was also seen in 30 patients with no hepatic diseases in whom it had a tendency to locate around the gallbladder fossa or in the periphery of the liver particularly in the left lobe. The knowledge of the prevalence, shape, distribution and causes of THAD is essential for the evaluation of contrast-enhanced CT images obtained during the arterial phase. (author)

  10. Southern San Andreas Fault seismicity is consistent with the Gutenberg-Richter magnitude-frequency distribution

    Science.gov (United States)

    Page, Morgan T.; Felzer, Karen

    2015-01-01

    The magnitudes of any collection of earthquakes nucleating in a region are generally observed to follow the Gutenberg-Richter (G-R) distribution. On some major faults, however, paleoseismic rates are higher than a G-R extrapolation from the modern rate of small earthquakes would predict. This, along with other observations, led to formulation of the characteristic earthquake hypothesis, which holds that the rate of small to moderate earthquakes is permanently low on large faults relative to the large-earthquake rate (Wesnousky et al., 1983; Schwartz and Coppersmith, 1984). We examine the rate difference between recent small to moderate earthquakes on the southern San Andreas fault (SSAF) and the paleoseismic record, hypothesizing that the discrepancy can be explained as a rate change in time rather than a deviation from G-R statistics. We find that with reasonable assumptions, the rate changes necessary to bring the small and large earthquake rates into alignment agree with the size of rate changes seen in epidemic-type aftershock sequence (ETAS) modeling, where aftershock triggering of large earthquakes drives strong fluctuations in the seismicity rates for earthquakes of all magnitudes. The necessary rate changes are also comparable to rate changes observed for other faults worldwide. These results are consistent with paleoseismic observations of temporally clustered bursts of large earthquakes on the SSAF and the absence of M greater than or equal to 7 earthquakes on the SSAF since 1857.

  11. Use of Frequency Distribution Functions to Establish Safe Conditions in Relation to the Foodborne Pathogen Bacillus cereus

    Directory of Open Access Journals (Sweden)

    Begoña Delgado

    2005-01-01

    Full Text Available Minimal processing implementation greatly depends on a detailed knowledge of the effects of preservation factors and their combinations on the spoilage and foodborne pathogenic microorganisms. The effectiveness of mild preservation conditions will become increasingly dependent on a more stochastic approach linking microbial physiological factors with product preservation factors. In this study, the validity of frequency distributions to efficiently describe the inactivation and growth of Bacillus cereus in the presence of natural antimicrobials (essential oils has been studied. For this purpose, vegetative cells were exposed to 0.6 mM of thymol or cymene, obtaining survival curves that were best described by the distribution of Weibull, since a tailing effect was observed. B. cereus was also exposed in a growth medium to a low concentration (0.1 mM of both antimicrobials, separately or combined, and the lag times obtained were fitted to a normal distribution, which allowed a description of dispersion of the start of growth. This allowed a more efficient evaluation of the experimental data to establish safe processing conditions according to accurate parameters and their implementation in risk assessment.

  12. Modeling and distributed gain scheduling strategy for load frequency control in smart grids with communication topology changes.

    Science.gov (United States)

    Liu, Shichao; Liu, Xiaoping P; El Saddik, Abdulmotaleb

    2014-03-01

    In this paper, we investigate the modeling and distributed control problems for the load frequency control (LFC) in a smart grid. In contrast with existing works, we consider more practical and real scenarios, where the communication topology of the smart grid changes because of either link failures or packet losses. These topology changes are modeled as a time-varying communication topology matrix. By using this matrix, a new closed-loop power system model is proposed to integrate the communication topology changes into the dynamics of a physical power system. The globally asymptotical stability of this closed-loop power system is analyzed. A distributed gain scheduling LFC strategy is proposed to compensate for the potential degradation of dynamic performance (mean square errors of state vectors) of the power system under communication topology changes. In comparison to conventional centralized control approaches, the proposed method can improve the robustness of the smart grid to the variation of the communication network as well as to reduce computation load. Simulation results show that the proposed distributed gain scheduling approach is capable to improve the robustness of the smart grid to communication topology changes. © 2013 ISA. Published by ISA. All rights reserved.

  13. Plasma Temperature Determination of Hydrogen Containing High-Frequency Electrode less Lamps by Intensity Distribution Measurements of Hydrogen Molecular Band

    International Nuclear Information System (INIS)

    Gavare, Z.; Revalde, G.; Skudra, A.

    2011-01-01

    The goal of the present work was the investigation of the possibility to use intensity distribution of the Q-branch lines of the hydrogen Fulcher-a diagonal band (d3η u- a3Σg + electronic transition; Q-branch with ν=ν=2) to determine the temperature of hydrogen containing high-frequency electrode less lamps (HFEDLs). The values of the rotational temperatures have been obtained from the relative intensity distributions for hydrogen-helium and hydrogen-argon HFEDLs depending on the applied current. The results have been compared with the method of temperature derivation from Doppler profiles of He 667.8 nm and Ar 772.4 nm lines. The results of both methods are in good agreement, showing that the method of gas temperature determination from the intensity distribution in the hydrogen Fulcher-a (2-2)Q band can be used for the hydrogen containing HFEDLs. It was observed that the admixture of 10% hydrogen in the argon HFEDLs significantly reduces the gas temperature

  14. Application of Linear Quadratic Gaussian and Coefficient Diagram Techniques to Distributed Load Frequency Control of Power Systems

    Directory of Open Access Journals (Sweden)

    Tarek Hassan Mohamed

    2015-12-01

    Full Text Available This paper presented both the linear quadratic Gaussian technique (LQG and the coefficient diagram method (CDM as load frequency controllers in a multi-area power system to deal with the problem of variations in system parameters and load demand change. The full states of the system including the area frequency deviation have been estimated using the Kalman filter technique. The efficiency of the proposed control method has been checked using a digital simulation. Simulation results indicated that, with the proposed CDM + LQG technique, the system is robust in the face of parameter uncertainties and load disturbances. A comparison between the proposed technique and other schemes is carried out, confirming the superiority of the proposed CDM + LQG technique.

  15. Study on the performance of quantum key distribution scheme with the single photon frequency up-conversion detector

    Science.gov (United States)

    Shi, Lei; Luo, Jun Wen; Xue, Yang; Wei, Jiahua

    2017-10-01

    In order to improve the detection efficiency in QKD system, this paper has put forward a new quantum key distribution scheme based on the single photon frequency up-conversion detection technology and decoy-state BB84 protocol. A long wavelength pump light is adopted in single photon detector (SPD) to avoid the noise caused by spontaneous parametric down conversion (SPDC), thus an overall 28% detection efficiency is achieved which is five times of 4.5% in conventional InGaAs-based detectors. Moreover, the propagating distances has reached 90km and 150km with weak coherent pulse (WCP) and decoy weak coherent pulse (DWCP) respectively, which is 1.3 times and 1.05 times of the conventional InGaAs-based detectors of 70km and 140km.

  16. Semicircular canal dehiscence: Frequency and distribution on temporal bone CT and its relationship with the clinical outcomes

    International Nuclear Information System (INIS)

    Elmali, Muzaffer; Polat, Ahmet Veysel; Kucuk, Harun; Atmaca, Sinan; Aksoy, Ahmet

    2013-01-01

    Purpose: In this study, we aimed to investigate the frequency of SCD and its distribution and relationship with clinical outcomes on thin-section CT of the temporal bone. Materials and methods: Digital temporal bone CT images of 850 consecutive patients (1700 temporal bone CTs, 5100 SCs) who presented with a range of complaints such as vertigo, deafness, ear pain, fullness, and discharge between January 2008 and December 2011 were re-evaluated. Axial and oblique coronal reconstruction images of the temporal bone were made with a reconstruction thickness of 0.5 mm. Additionally, superior SC was evaluated in two perpendicular planes. Results: Out of 850 patients, 70 had completely normal temporal bone CT. Ninety-three patients had at least one SCD. In the temporal bone-based evaluation, 119 (26 bilateral, 67 unilateral) of 1700 temporal bones (7%) showed dehiscence. The SC-based evaluation revealed 125 SCD (2.5%) in 5100 SCs. The total number and rates of SCD were as follows: superior 103 (82.4%), posterior 13 (10.4%), and lateral nine (7.2%). Twenty of the 93 patients with SCD (21.5%) revealed no other findings on their temporal bone CTs. We determined a significant correlation between vestibular complaints, conductive hearing loss and SCD but there was no correlation between mixed, sensorineural hearing loss and SCD. Conclusion: We determined the frequency of SCD in 11% of patients and 7% of temporal bones. With regards to the distribution, the superior SC showed the highest dehiscence rate (82.4%). We found a significant correlation between vestibular symptoms, conductive hearing loss and SCD

  17. Semicircular canal dehiscence: Frequency and distribution on temporal bone CT and its relationship with the clinical outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Elmali, Muzaffer, E-mail: muzafel@yahoo.com.tr [Department of Radiology, Ondokuz Mayis University, Faculty of Medicine, Samsun (Turkey); Polat, Ahmet Veysel, E-mail: veyselp@hotmail.com [Department of Radiology, Ondokuz Mayis University, Faculty of Medicine, Samsun (Turkey); Kucuk, Harun, E-mail: hardrmd@yahoo.com [Department of Otorhinolaryngology, Ondokuz Mayis University, Faculty of Medicine, Samsun (Turkey); Atmaca, Sinan, E-mail: sinanatmaca@yahoo.com [Department of Otorhinolaryngology, Ondokuz Mayis University, Faculty of Medicine, Samsun (Turkey); Aksoy, Ahmet, E-mail: toxocara47@hotmail.com [Department of Otorhinolaryngology, Ondokuz Mayis University, Faculty of Medicine, Samsun (Turkey)

    2013-10-01

    Purpose: In this study, we aimed to investigate the frequency of SCD and its distribution and relationship with clinical outcomes on thin-section CT of the temporal bone. Materials and methods: Digital temporal bone CT images of 850 consecutive patients (1700 temporal bone CTs, 5100 SCs) who presented with a range of complaints such as vertigo, deafness, ear pain, fullness, and discharge between January 2008 and December 2011 were re-evaluated. Axial and oblique coronal reconstruction images of the temporal bone were made with a reconstruction thickness of 0.5 mm. Additionally, superior SC was evaluated in two perpendicular planes. Results: Out of 850 patients, 70 had completely normal temporal bone CT. Ninety-three patients had at least one SCD. In the temporal bone-based evaluation, 119 (26 bilateral, 67 unilateral) of 1700 temporal bones (7%) showed dehiscence. The SC-based evaluation revealed 125 SCD (2.5%) in 5100 SCs. The total number and rates of SCD were as follows: superior 103 (82.4%), posterior 13 (10.4%), and lateral nine (7.2%). Twenty of the 93 patients with SCD (21.5%) revealed no other findings on their temporal bone CTs. We determined a significant correlation between vestibular complaints, conductive hearing loss and SCD but there was no correlation between mixed, sensorineural hearing loss and SCD. Conclusion: We determined the frequency of SCD in 11% of patients and 7% of temporal bones. With regards to the distribution, the superior SC showed the highest dehiscence rate (82.4%). We found a significant correlation between vestibular symptoms, conductive hearing loss and SCD.

  18. Taxonomic key for the genera of Elmidae (Coleoptera, Byrrhoidea) occurring in Goiás State, Brazil, including new records and distributional notes

    OpenAIRE

    Barbosa, Felipe F.; Fernandes, André S.; Oliveira, Leandro G.

    2013-01-01

    A taxonomic key for the genera of Elmidae (Coleoptera, Byrrhoidea) occurring in Goiás State, Brazil, including new records and distributional notes. Despite their great diversity and high abundance in Neotropical aquatic environments, the fauna of Elmidae remains practically unknown in some areas and even entire biomes in this region. In this work we bring, for the first time, faunistic data for the Elmidae of central Brazil. The aim of this work was to inventory the Elmidae fauna in central,...

  19. Measuring the length distribution of self-assembled lipid nanotubes by orientation control with a high-frequency alternating current electric field in aqueous solutions.

    Science.gov (United States)

    Hirano, Ken; Aoyagi, Masaru; Ishido, Tomomi; Ooie, Toshihiko; Frusawa, Hiroshi; Asakawa, Masumi; Shimizu, Toshimi; Ishikawa, Mitsuru

    2009-02-15

    The present work addresses the length distribution of self-assembled lipid nanotubes (LNTs) by controlling the orientation of the LNTs using an alternating current (ac) electric field in aqueous solutions. The effect of the ac field on the orientation and rotation of individual LNTs was examined to evaluate the optimum orientation frequency by visualizing the individual LNTs in real time. By using the high-frequency ac field, we have successfully measured the length distribution for two different types of LNTs and have quantitatively analyzed the maximum occurrences of the length distribution as well as the extension of the longer length region.

  20. Frequency and spatial distribution of animal and object hoarder behavior in Curitiba, Paraná State, Brazil

    Directory of Open Access Journals (Sweden)

    Graziela Ribeiro da Cunha

    Full Text Available Abstract: This study aimed to establish the frequency and spatial distribution of animal and object hoarding in Curitiba (Paraná State, the eighth most populous city in Brazil. All hoarding complaints received by the City Secretaries of Health, Environment and Social Assistance between September 2013 and April 2015 were collected (n = 226 and suspicious cases were individually investigated. A total of 113/226 (50% of complaints were confirmed as hoarding cases, representing an overall ratio of 6.45 cases per 100,000 inhabitants in Curitiba, of which 48/113 (42.5% involved object hoarders, 41/113 (36.3% animal hoarders and 24/113 (21.2% both animal and object hoarders. A correlation of total identified cases with neighborhood population density and all population stratums analyzed (total, gender, age was significantly positive (p < 0.01, and with neighborhood mean monthly income (r = -0.2; p = 0.03 significantly negative. A spatial cluster of cases was found in the north of the city (OR = 8.57; p < 0.01. Hoarding cases were relatively frequent in Curitiba and were associated with population distribution patterns and inversely related to neighborhood income.

  1. Updating the geographical distribution and frequency of Aedes albopictus in Brazil with remarks regarding its range in the Americas

    Directory of Open Access Journals (Sweden)

    Roberta Gomes Carvalho/

    2014-09-01

    Full Text Available The geographical distribution of Aedes albopictus in Brazil was updated according to the data recorded across the country over the last eight years. Countrywide house indexes (HI for Ae. albopictus in urban and suburban areas were described for the first time using a sample of Brazilian municipalities. This mosquito is currently present in at least 59% of the Brazilian municipalities and in 24 of the 27 federal units (i.e., 26 states and the Federal District. In 34 Brazilian municipalities, the HI values for Ae. albopictus were higher than those recorded for Ae. aegypti, reaching figures as high as HI = 7.72 in the Southeast Region. Remarks regarding the current range of this mosquito species in the Americas are also presented. Nineteen American countries are currently infested and few mainland American countries have not confirmed the occurrence of Ae. albopictus. The large distribution and high frequency of Ae. albopictus in the Americas may become a critical factor in the spread of arboviruses like chikungunya in the new world.

  2. Effect of trophic level on the radiocesium frequency distribution in aquatic and terrestrial ecosystems at Chornobyl and nuclear sites in the United States

    International Nuclear Information System (INIS)

    Smith, Michael H.; Tsyusko-Omeltchenko, Olga; Oleksyk, Taras K.

    2003-01-01

    There are significant linear relationship between the standard deviation and the mean of radiocesium concentration for samples of soils, sediments, plants, and animals from Chornobyl and nuclear sites in the United States. The universal occurrence of this relationship in all types of samples suggests that a non-normal frequency distribution should be expected. The slopes of these relationships are similar for fish and mammals from the two regions of the world but those for plants are not. The slopes for plants are similar for aquatic and terrestrial ecosystems within each region. We hypothesize that there are relationships between the four moments of the frequency distribution of radiocesium (mean, variance, skewness, and kurtosis), and that these relationships are caused by the functional properties of the organisms and other characteristics of the ecosystem. The way in which radiocesium was distributed across the landscape does not seem to be a factor in determining the form of the frequency distribution. (author)

  3. Distribution of very low frequency earthquakes in the Nankai accretionary prism influenced by a subducting-ridge

    Science.gov (United States)

    Toh, Akiko; Obana, Koichiro; Araki, Eiichiro

    2018-01-01

    We investigated the distribution of very low frequency earthquakes (VLFEs) that occurred in the shallow accretionary prism of the eastern Nankai trough during one week of VLFE activity in October 2015. They were recorded very close from the sources by an array of broadband ocean bottom seismometers (BBOBSs) equipped in Dense Oceanfloor Network system for Earthquakes and Tsunamis 1 (DONET1). The locations of VLFEs estimated using a conventional envelope correlation method appeared to have a large scatter, likely due to effects of 3D structures near the seafloor and/or sources that the method could not handle properly. Therefore, we assessed their relative locations by introducing a hierarchal clustering analysis based on patterns of relative peak times of envelopes within the array measured for each VLFE. The results suggest that, in the northeastern side of the network, all the detected VLFEs occur 30-40 km landward of the trench axis, near the intersection of a splay fault with the seafloor. Some likely occurred along the splay fault. On the other hand, many VLFEs occur closer to the trench axis in the southwestern side, likely along the plate boundary, and the VLFE activity in the shallow splay fault appears less intense, compared to the northeastern side. Although this could be a snap-shot of activity that becomes more uniform over longer-term, the obtained distribution can be reasonably explained by the change in shear stresses and pore pressures caused by a subducting-ridge below the northeastern side of DONET1. The change in stress state along the strike of the plate boundary, inferred from the obtained VLFE distribution, should be an important indicator of the strain release pattern and localised variations in the tsunamigenic potential of this region.

  4. EPR spectroscopy of MRI-related Gd(III) complexes: simultaneous analysis of multiple frequency and temperature spectra, including static and transient crystal field effects.

    Science.gov (United States)

    Rast, S; Borel, A; Helm, L; Belorizky, E; Fries, P H; Merbach, A E

    2001-03-21

    For the first time, a very general theoretical method is proposed to interpret the full electron paramagnetic resonance (EPR) spectra at multiple temperatures and frequencies in the important case of S-state metal ions complexed in liquid solution. This method is illustrated by a careful analysis of the measured spectra of two Gd3+ (S = 7/2) complexes. It is shown that the electronic relaxation mechanisms at the origin of the EPR line shape arise from the combined effects of the modulation of the static crystal field by the random Brownian rotation of the complex and of the transient zero-field splitting. A detailed study of the static crystal field mechanism shows that, contrarily to the usual global models involving only second-order terms, the fourth and sixth order terms can play a non-negligible role. The obtained parameters are well interpreted in the framework of the physics of the various underlying relaxation processes. A better understanding of these mechanisms is highly valuable since they partly control the efficiency of paramagnetic metal ions in contrast agents for medical magnetic resonance imaging (MRI).

  5. Distribution of allelic and genotypic frequencies of IL1A, IL4, NFKB1 and PAR1 variants in Native American, African, European and Brazilian populations.

    Science.gov (United States)

    Amador, Marcos A T; Cavalcante, Giovanna C; Santos, Ney P C; Gusmão, Leonor; Guerreiro, João F; Ribeiro-dos-Santos, Ândrea; Santos, Sidney

    2016-02-16

    The inflammatory response plays a key role at different stages of cancer development. Allelic variants of the interleukin 1A (IL1A), interleukin 4 (IL4), nuclear factor kappa B1 (NFKB1) and protease-activated receptor 1 (PAR1) genes may influence not only the inflammatory response but also susceptibility to cancer development. Among major ethnic or continental groups, these polymorphic variants present different allelic frequencies. In admixed populations, such as the Brazilian population, data on distribution of these polymorphisms are limited. Here, we collected samples of cancer-free individuals from the north, northeast, midwest, south and southeast regions of Brazil and from the three main groups that gave rise to the Brazilian population: Native Americans from the Brazilian Amazon, Africans and Europeans. We describe the allelic distributions of four IL1A (rs3783553), IL4 (rs79071878), NFKB1 (rs28362491) and PAR1 (rs11267092) gene polymorphisms, which the literature describes as polymorphisms with a risk of cancer or worse prognosis for cancer. The genotypic distribution of the four polymorphisms was statistically distinct between Native Americans, Africans and Europeans. For the allelic frequency of these polymorphisms, the Native American population was the most distinct among the three parental populations, and it included the greatest number of alleles with a risk of cancer or worse prognosis for cancer. The PAR1 gene polymorphism allelic distribution was similar among all Brazilian regions. For the other three markers, the northern region population was statistically distinct from other Brazilian region populations. The IL1A, IL4, NFKB1 and PAR1 gene polymorphism allelic distributions are homogeneous among the regional Brazilian populations, except for the northern region, which significantly differs from the other four Brazilian regions. Among the parental populations, the Native American population exhibited a higher incidence of alleles with risk of

  6. Morphological Atherosclerosis Calcification Distribution (MACD) Index is a Strong Predictor of Cardio-Vascular Death and Include Predictive Power of BMD

    DEFF Research Database (Denmark)

    Christiansen, Claus; Karsdal, Morten; Ganz, Melanie

    Aortic calcification is a major risk factor for cardiovascular disease (CVD) related deaths. We investigated the relation between mortality and aspects of number, size, morphology and distribution of calcified plaques in the lumbar aorta and BMD of postmenopausal women. 308 women aged 48 to 76 were...... was significantly higher than AC24 and any single or multivariate metabolic/physical marker. BMD correlates with AC24 among CVD dead patients (p=0.03) unlike MACD (p=0.43). The recent MACD-index provides a unique combination of morphology and distribution of aortic calcifications, factors that in a combination...... increase the biological relevance of the index by emphasizing that smaller plaques with a spread elongated morphology have a larger growth potential and thereby subsequent rupture potential. It includes the predictive power of BMD unlike the AC24 index. Thereby, in the current cohort with a long term...

  7. High frequency of cutaneous manifestations including vitiligo and alopecia areata in a prospective cohort of patients with chronic graft-vs-host disease

    Science.gov (United States)

    Čeović, Romana; Desnica, Lana; Pulanić, Dražen; Serventi Seiwerth, Ranka; Ilić, Ivana; Grce, Magdalena; Mravak Stipetić, Marinka; Klepac Pulanić, Tajana; Bilić, Ervina; Bilić, Ernest; Milošević, Milan; Vrhovac, Radovan; Nemet, Damir; Pavletic, Steven Z

    2016-01-01

    Aim To determine the frequency and the characteristics of cutaneous manifestations, especially vitiligo and alopecia areata, in patients with chronic graft-vs-host disease (cGVHD). Methods 50 patients with cGVHD were prospectively enrolled in the observational study protocol and evaluated by an experienced dermatologist. The evaluation was focused on the clinical spectrum of skin and adnexal involvement, and the cutaneous GVHD score was determined according to National Institutes of Health (NIH) Consensus criteria. The presence of vitiligo, alopecia, xerosis, nail changes, and dyspigmentation was also assessed. Results Out of 50 cGVHD patients, 28 (56%) had skin involvement, and 27 of them (96%) had hypo and/or hyperpigmentations. 11 patients (39%) had a mild cutaneous NIH cGVHD score, 22% moderate, and 39% severe. 15 (30%) patients had nail changes and 10 (20%) had vitiligo or alopecia areata. Univariate analysis showed that patients with vitiligo/alopecia areata received more lines of prior systemic immunosuppressive therapy (P = 0.043), had lower Karnofsky performance status (P = 0.028), and had a higher B-cell number (P = 0.005), platelet count (P = 0.022), and total protein (P = 0.024). Vitiligo and alopecia areata were associated with higher NIH skin score (P = 0.001), higher intensity of immunosuppressive treatment (P = 0.020), and total body irradiation conditioning (P = 0.040). Multivariate regression model showed that patients with higher NIH skin scoring were 3.67 times more likely to have alopecia and/or vitiligo (odds ratio 3.67; 95% confidence interval 1.26-10.73), controlled for all other factors in the model (age at study entry, number of B-cells, platelet count, and global NIH score). Conclusion These data indicate that vitiligo and alopecia areata occur more frequently in cGVHD than previously reported. PMID:27374824

  8. End plate marrow changes in the asymptomatic lumbosacral spine: frequency, distribution and correlation with age and degenerative changes

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Christine B. [Department of Radiology, VA Healthcare System, 3350 La Jolla Village Drive, CA 92161, La Jolla (United States); Vande Berg, Bruno C.; Malghem, Jacques [Department of Radiology, Cliniques Universitaires St Luc Universite Catholique de Louvain, 10 av Hippocrate, 1200, Brussels (Belgium); Tavernier, Thierry [Service de Radiologie, Clinique de la Sauvegarde, Av David Ben Gourion, 69009, Lyon (France); Cotten, Anne [Service de Radiologie Osteoarticulaire, Hopital R Salengro, 59037, Lille Cedex (France); Laredo, Jean-Denis [Service de Radiologie Osteo-articulaire, Hopital Lariboisiere, 2 rue Ambroise Pare, 75475, Paris Cedex 10 (France); Vallee, Christian [Service d' imagerie medicale, Hopital Raymond Poincare, 104 Boulevard R.Poincare, 92380, Garches (France)

    2004-07-01

    To investigate the frequency and distribution of end plate marrow signal intensity changes in an asymptomatic population and to correlate these findings with patient age and degenerative findings in the spine. MR imaging studies of the lumbosacral (LS) spine in 59 asymptomatic subjects were retrospectively reviewed by 2 musculoskeletal radiologists to determine the presence and location of fat-like and edema-like marrow signal changes about the end plates of the L1-2 through L5-S1 levels. The presence of degenerative changes in the spine was recorded as was patient age. Descriptive statistics were utilized to determine the frequency and associations of end plate findings and degenerative changes in the spine. Interobserver variability was determined by a kappa score. Binomial probability was used to predict the prevalence of the end plate changes in a similar subject population. The Fisher exact test was performed to determine statistical significance of the relationship of end plate changes with degenerative changes in the spine, superior versus inferior location about the disc and age of the patient population. Focal fat-like signal intensity adjacent to the vertebral end-plate was noted in 15 out of 59 subjects by both readers, and involved 38 and 36 out of 590 end plates by readers 1 and 2, respectively. Focal edema-like signal intensity adjacent to the vertebral end plate was noted in 8 out of 59 subjects by both readers and involved 11 and 10 out of 590 end plates by readers 1 and 2, respectively. Either fat or edema signal intensity occurred most often at the anterior (p<.05) aspects of the mid-lumbar spine and was seen in an older sub-population of the study (p<.05). End plate marrow signal intensity changes are present in the lumbar spine of some asymptomatic subjects with a characteristic location along the spine and in vertebral end plates. (orig.)

  9. End plate marrow changes in the asymptomatic lumbosacral spine: frequency, distribution and correlation with age and degenerative changes

    International Nuclear Information System (INIS)

    Chung, Christine B.; Vande Berg, Bruno C.; Malghem, Jacques; Tavernier, Thierry; Cotten, Anne; Laredo, Jean-Denis; Vallee, Christian

    2004-01-01

    To investigate the frequency and distribution of end plate marrow signal intensity changes in an asymptomatic population and to correlate these findings with patient age and degenerative findings in the spine. MR imaging studies of the lumbosacral (LS) spine in 59 asymptomatic subjects were retrospectively reviewed by 2 musculoskeletal radiologists to determine the presence and location of fat-like and edema-like marrow signal changes about the end plates of the L1-2 through L5-S1 levels. The presence of degenerative changes in the spine was recorded as was patient age. Descriptive statistics were utilized to determine the frequency and associations of end plate findings and degenerative changes in the spine. Interobserver variability was determined by a kappa score. Binomial probability was used to predict the prevalence of the end plate changes in a similar subject population. The Fisher exact test was performed to determine statistical significance of the relationship of end plate changes with degenerative changes in the spine, superior versus inferior location about the disc and age of the patient population. Focal fat-like signal intensity adjacent to the vertebral end-plate was noted in 15 out of 59 subjects by both readers, and involved 38 and 36 out of 590 end plates by readers 1 and 2, respectively. Focal edema-like signal intensity adjacent to the vertebral end plate was noted in 8 out of 59 subjects by both readers and involved 11 and 10 out of 590 end plates by readers 1 and 2, respectively. Either fat or edema signal intensity occurred most often at the anterior (p<.05) aspects of the mid-lumbar spine and was seen in an older sub-population of the study (p<.05). End plate marrow signal intensity changes are present in the lumbar spine of some asymptomatic subjects with a characteristic location along the spine and in vertebral end plates. (orig.)

  10. Proline: the distribution, frequency, positioning, and common functional roles of proline and polyproline sequences in the human proteome.

    Directory of Open Access Journals (Sweden)

    Alexander A Morgan

    Full Text Available Proline is an anomalous amino acid. Its nitrogen atom is covalently locked within a ring, thus it is the only proteinogenic amino acid with a constrained phi angle. Sequences of three consecutive prolines can fold into polyproline helices, structures that join alpha helices and beta pleats as architectural motifs in protein configuration. Triproline helices are participants in protein-protein signaling interactions. Longer spans of repeat prolines also occur, containing as many as 27 consecutive proline residues. Little is known about the frequency, positioning, and functional significance of these proline sequences. Therefore we have undertaken a systematic bioinformatics study of proline residues in proteins. We analyzed the distribution and frequency of 687,434 proline residues among 18,666 human proteins, identifying single residues, dimers, trimers, and longer repeats. Proline accounts for 6.3% of the 10,882,808 protein amino acids. Of all proline residues, 4.4% are in trimers or longer spans. We detected patterns that influence function based on proline location, spacing, and concentration. We propose a classification based on proline-rich, polyproline-rich, and proline-poor status. Whereas singlet proline residues are often found in proteins that display recurring architectural patterns, trimers or longer proline sequences tend be associated with the absence of repetitive structural motifs. Spans of 6 or more are associated with DNA/RNA processing, actin, and developmental processes. We also suggest a role for proline in Kruppel-type zinc finger protein control of DNA expression, and in the nucleation and translocation of actin by the formin complex.

  11. Regolith thickness over Sinus Iridum: Results from morphology and size-frequency distribution of small impact craters

    Science.gov (United States)

    Fa, Wenzhe; Liu, Tiantian; Zhu, Meng-Hua; Haruyama, Junichi

    2014-08-01

    High-resolution optical images returned from recent lunar missions provide a new chance for estimation of lunar regolith thickness using morphology and the size-frequency distribution of small impact craters. In this study, regolith thickness over the Sinus Iridum region is estimated using Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Cameras (NACs) images. A revised relationship between crater geometry and regolith thickness is proposed based on old experimental data that takes into considering the effect of the illumination angle of the images. In total, 227 high-resolution LROC NAC images are used, and 378,556 impact craters with diameters from 4.2 to 249.8 m are counted, and their morphologies are identified. Our results show that 50% of the Sinus Iridum region has a regolith thickness between 5.1 and 10.7 m, and the mean and median regolith thicknesses are 8.5 and 8.0 m, respectively. There are substantial regional variations in the regolith thickness, with its median value varying from 2.6 to 12.0 m for most regions. Local variations of regolith thickness are found to be correlated with the lunar surface age: the older the surface, the greater the thickness. In addition, sporadically distributed impact ejecta and crater rays are associated with relatively larger regolith thickness, which might result from excavation and transport of materials during the formation of the secondaries of Copernican-aged craters. Our estimated regolith thickness can help with future analysis of Chang'E-3 lunar penetrating radar echoes and studies of the subsurface stratigraphic structure of the Moon.

  12. A Dataset for Three-Dimensional Distribution of 39 Elements Including Plant Nutrients and Other Metals and Metalloids in the Soils of a Forested Headwater Catchment.

    Science.gov (United States)

    Wu, B; Wiekenkamp, I; Sun, Y; Fisher, A S; Clough, R; Gottselig, N; Bogena, H; Pütz, T; Brüggemann, N; Vereecken, H; Bol, R

    2017-11-01

    Quantification and evaluation of elemental distribution in forested ecosystems are key requirements to understand element fluxes and their relationship with hydrological and biogeochemical processes in the system. However, datasets supporting such a study on the catchment scale are still limited. Here we provide a dataset comprising spatially highly resolved distributions of 39 elements in soil profiles of a small forested headwater catchment in western Germany () to gain a holistic picture of the state and fluxes of elements in the catchment. The elements include both plant nutrients and other metals and metalloids that were predominately derived from lithospheric or anthropogenic inputs, thereby allowing us to not only capture the nutrient status of the catchment but to also estimate the functional development of the ecosystem. Soil samples were collected at high lateral resolution (≤60 m), and element concentrations were determined vertically for four soil horizons (L/Of, Oh, A, B). From this, a three-dimensional view of the distribution of these elements could be established with high spatial resolution on the catchment scale in a temperate natural forested ecosystem. The dataset can be combined with other datasets and studies of the TERENO (Terrestrial Environmental Observatories) Data Discovery Portal () to reveal elemental fluxes, establish relations between elements and other soil properties, and/or as input for modeling elemental cycling in temperate forested ecosystems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  13. The distribution and frequency of blood lipid testing by sociodemographic status among adults in Auckland, New Zealand.

    Science.gov (United States)

    Exeter, Daniel J; Moss, Lauren; Zhao, Jinfeng; Kyle, Cam; Riddell, Tania; Jackson, Rod; Wells, Susan

    2015-09-01

    National cardiovascular disease (CVD) guidelines recommend that adults have cholesterol levels monitored regularly. However, little is known about the extent and equity of cholesterol testing in New Zealand. To investigate the distribution and frequency of blood lipid testing by sociodemographic status in Auckland, New Zealand. We anonymously linked five national health datasets (primary care enrolment, laboratory tests, pharmaceuticals, hospitalisations and mortality) to identify adults aged ≥25 years without CVD or diabetes who had their lipids tested in 2006-2010, by age, gender, ethnicity and area of residence and deprivation. Multivariate logistic regression was used to estimate the likelihood of testing associated with these factors. Of the 627 907 eligible adults, 66.3% had at least one test between 2006 and 2010. Annual testing increased from 24.7% in 2006 to 35.1% in 2010. Testing increased with age similarly for men and women. Indian people were 87% more likely than New Zealand European and Others (NZEO) to be tested, Pacific people 8% more likely, but rates for Maori were similar to NZEO. There was marked variation within the region, with residents of the most deprived areas less likely to be tested than residents in least deprived areas. Understanding differences within and between population groups supports the development of targeted strategies for better service utilisation. While lipid testing has increased, sociodemographic variations persist by place of residence, and deprivation. Of the high CVD risk populations, lipid testing for Maori and Pacific is not being conducted according to need.

  14. Assessing the boron nutritional status by analyzing its cummulative frequency distribution in the hair and whole blood.

    Science.gov (United States)

    Prejac, Juraj; Skalny, Andrey A; Grabeklis, Andrei R; Uzun, Suzana; Mimica, Ninoslav; Momčilović, Berislav

    2018-01-01

    Boron is a non-essential ubiquitous trace element in the human body. The aim of this study was to assess boron nutritional status by analyzing boron frequency distribution in the long-term biological indicator tissue of hair and the short-term biological indicator of whole blood. Hair samples were analyzed in 727 apparently healthy subjects (263 ♂ and 464 ♀) and the whole blood boron was analyzed in the random subsample of them (80 ♂ and 152 ♀). Samples were analyzed by the ICP-MS at the Center for Biotic Medicine, Moscow, Russia. The adequate reference range for hair boron concentration was (μg∙g -1 ) 0.771- 6.510 for men and distinctly lower 0.472-3.89 for women; there was no detectable difference in the whole blood boron for the adequate reference range between men (0.020-.078) and women (0019-0.062). Boron may play an essential role in the metabolism of the connective tissue of the biological bone matrix. Copyright © 2017. Published by Elsevier GmbH.

  15. Comparative analysis of HLA II allele and genotype frequency distribution in patients with type 1 diabetes mellitus and autoimmune thyroiditis

    Directory of Open Access Journals (Sweden)

    Ekaterina Aleksandrovna Repina

    2013-12-01

    Full Text Available Aim. To compare HLA II allele and genotype frequency distribution in type 1 diabetes mellitus (T1DM and autoimmune thyroiditis (AIT with that in isolated T1DM.Materials and Methods. A total of 92 T1DM patients were subdivided into two groups. The first group comprised 54 patients with established AIT comorbidity or elevation of anti-thyroid autoantibodies (ATA. Patients with isolated T1DM (ATA-negative formed the second group. HLA-genotyping was performed by multiprimer PCR set for the three following genes: DRB1, DQA1 and DQВ1.Results. Prevalence of alleles DRB1*01, *03(017, *04, *07, *11 and genotypes 01/03, 01/04, 03/04 tends to be higher among patients with AIT comorbidity. The comorbidity group was also characterized by the trend towards higher prevalence of “marker/marker” and “marker/non-marker” combinations favouring the former variant. Conversely, ATA-negative patients exhibited trend for higher prevalence of “non-marker/non-marker” combination.Conclusion. Statistically insignificant difference between HLA II alleles and genotypes in the two studied groups suggests that primary genetic factors are common in these two diseases. Plausibly, genes other than DRB1, DQA1 and DQВ1 determine the localization of the autoimmune process.

  16. Frequency, distribution and time trends of types of leisure-time physical activity in Brazil, 2006-2012.

    Science.gov (United States)

    de Sa, Thiago Herick; Garcia, Leandro Martin Totaro; Claro, Rafael Moreira

    2014-12-01

    To describe the frequency and the distribution of the main types of leisure time physical activity (LTPA) practiced by Brazilian adults in 2012 and to observe their time trends from 2006 to 2012. Cross-sectional data from the Brazilian surveillance system of risk and protective factors for non-transmissible chronic diseases from 2006 to 2012 (around 54,000 adults aged 18 years or older in all Brazilian State capitals interviewed yearly). Participants were asked whether they had practiced any type of exercise or sport in the last 3 months, and if so which type. Linear regression was used to identify trends of the five most cited LTPA. In 2012, walking was reported as the main LTPA (18.1 %), followed by strength training/gymnastics (11.2 %) and football (7.2 %). Time-trend analysis showed reduction in football (9.1-7.2 %; p = 0.004, β = -0.25, R(2) = 0.79) and increase in strength training/gymnastics (7.9-11.2 %; p = 0.02, β = 0.50, R(2) = 0.62) and running (1.7-3.1 %; p < 0.001, β = 0.22, R(2) = 0.93). Walking was the main type of LTPA. Patterns of LTPA types remained relatively stable over the last 7 years.

  17. Spatial and Temporal Analysis on the Distribution of Active Radio-Frequency Identification (RFID Tracking Accuracy with the Kriging Method

    Directory of Open Access Journals (Sweden)

    Xin Liu

    2014-10-01

    Full Text Available Radio frequency identification (RFID technology has already been applied in a number of areas to facilitate the tracking process. However, the insufficient tracking accuracy of RFID is one of the problems that impedes its wider application. Previous studies focus on examining the accuracy of discrete points RFID, thereby leaving the tracking accuracy of the areas between the observed points unpredictable. In this study, spatial and temporal analysis is applied to interpolate the continuous distribution of RFID tracking accuracy based on the Kriging method. An implementation trial has been conducted in the loading and docking area in front of a warehouse to validate this approach. The results show that the weak signal area can be easily identified by the approach developed in the study. The optimum distance between two RFID readers and the effect of the sudden removal of readers are also presented by analysing the spatial and temporal variation of RFID tracking accuracy. This study reveals the correlation between the testing time and the stability of RFID tracking accuracy. Experimental results show that the proposed approach can be used to assist the RFID system setup process to increase tracking accuracy.

  18. Spatial and temporal analysis on the distribution of active radio-frequency identification (RFID) tracking accuracy with the Kriging method.

    Science.gov (United States)

    Liu, Xin; Shannon, Jeremy; Voun, Howard; Truijens, Martijn; Chi, Hung-Lin; Wang, Xiangyu

    2014-10-29

    Radio frequency identification (RFID) technology has already been applied in a number of areas to facilitate the tracking process. However, the insufficient tracking accuracy of RFID is one of the problems that impedes its wider application. Previous studies focus on examining the accuracy of discrete points RFID, thereby leaving the tracking accuracy of the areas between the observed points unpredictable. In this study, spatial and temporal analysis is applied to interpolate the continuous distribution of RFID tracking accuracy based on the Kriging method. An implementation trial has been conducted in the loading and docking area in front of a warehouse to validate this approach. The results show that the weak signal area can be easily identified by the approach developed in the study. The optimum distance between two RFID readers and the effect of the sudden removal of readers are also presented by analysing the spatial and temporal variation of RFID tracking accuracy. This study reveals the correlation between the testing time and the stability of RFID tracking accuracy. Experimental results show that the proposed approach can be used to assist the RFID system setup process to increase tracking accuracy.

  19. Variation in size frequency distribution of coral populations under different fishing pressures in two contrasting locations in the Indian Ocean.

    Science.gov (United States)

    Grimsditch, G; Pisapia, C; Huck, M; Karisa, J; Obura, D; Sweet, M

    2017-10-01

    This study aimed to assess how the size-frequency distributions of coral genera varied between reefs under different fishing pressures in two contrasting Indian Ocean locations (the Maldives and East Africa). Using generalized linear mixed models, we were able to demonstrate that complex interactions occurred between coral genera, coral size class and fishing pressure. In both locations, we found Acropora coral species to be more abundant in non-fished compared to fished sites (a pattern which was consistent for nearly all the assessed size classes). Coral genera classified as 'stress tolerant' showed a contrasting pattern i.e. were higher in abundance in fished compared to non-fished sites. Site specific variations were also observed. For example, Maldivian reefs exhibited a significantly higher abundance in all size classes of 'competitive' corals compared to East Africa. This possibly indicates that East African reefs have already been subjected to higher levels of stress and are therefore less suitable environments for 'competitive' corals. This study also highlights the potential structure and composition of reefs under future degradation scenarios, for example with a loss of Acropora corals and an increase in dominance of 'stress tolerant' and 'generalist' coral genera. Copyright © 2017. Published by Elsevier Ltd.

  20. Effect of Topography Degradation on Crater Size-Frequency Distributions: Implications for Populations of Small Craters and Age Dating

    Science.gov (United States)

    Xie, Minggang; Zhu, Meng-Hua; Xiao, Zhiyong; Wu, Yunzhao; Xu, Aoao

    2017-10-01

    Whether or not background secondary craters dominate populations of small impact craters on terrestrial bodies is a half-century controversy. It has been suggested that small craters on some planetary bodies are dominated by background secondary craters based partly on the steepened slope of crater size-frequency distribution (CSFD) toward small diameters, such as the less than 1 km diameter crater population on the lunar mare. Here we show that topography degradation enlarges craters and increases CSFD slopes with time. When topography degradation is taken into account, for various-aged crater populations, the observed steep CSFD at small diameters is uniformly consistent with an originally shallower CSFD, whose slope is undifferentiated from the CSFD slope estimated from near-Earth objects and terrestrial bolides. The results show that the effect of topography degradation on CSFD is important in dating planetary surfaces, and the steepening of CSFD slopes is not necessarily caused by secondary cratering, but rather a natural consequence of topography degradation.

  1. Smart microgrid hierarchical frequency control ancillary service provision based on virtual inertia concept: An integrated demand response and droop controlled distributed generation framework

    International Nuclear Information System (INIS)

    Rezaei, Navid; Kalantar, Mohsen

    2015-01-01

    Highlights: • Detailed formulation of the microgrid static and dynamic securities based on droop control and virtual inertia concepts. • Constructing a novel objective function using frequency excursion and rate of change of frequency profiles. • Ensuring the microgrid security subject to the microgrid economic and environmental policies. • Coordinated management of demand response and droop controlled distributed generation resources. • Precise scheduling of day-ahead hierarchical frequency control ancillary services using a scenario based stochastic programming. - Abstract: Low inertia stack, high penetration levels of renewable energy source and great ratio of power deviations in a small power delivery system put microgrid frequency at risk of instability. On the basis of the close coupling between the microgrid frequency and system security requirements, procurement of adequate ancillary services from cost-effective and environmental friendly resources is a great challenge requests an efficient energy management system. Motivated by this need, this paper presents a novel energy management system that is aimed to coordinately manage the demand response and distributed generation resources. The proposed approach is carried out by constructing a hierarchical frequency control structure in which the frequency dependent control functions of the microgrid components are modeled comprehensively. On the basis of the derived modeling, both the static and dynamic frequency securities of an islanded microgrid are provided in primary and secondary control levels. Besides, to cope with the low inertia stack of islanded microgrids, novel virtual inertia concept is devised based on the precise modeling of droop controlled distributed generation resources. The proposed approach is applied to typical test microgrid. Energy and hierarchical reserve resource are scheduled precisely using a scenario-based stochastic programming methodology. Moreover, analyzing the

  2. Energy evolution of the moments of the hadron distribution in QCD jets including NNLL resummation and NLO running-coupling corrections

    CERN Document Server

    Perez-Ramos, Redamy

    2014-01-01

    The moments of the single inclusive momentum distribution of hadrons in QCD jets, are studied in the next-to-modified-leading-log approximation (NMLLA) including next-to-leading-order (NLO) corrections to the alpha_s strong coupling. The evolution equations are solved using a distorted Gaussian parametrisation, which successfully reproduces the spectrum of charged hadrons of jets measured in e+e- collisions. The energy dependencies of the maximum peak, multiplicity, width, kurtosis and skewness of the jet hadron distribution are computed analytically. Comparisons of all the existing jet data measured in e+e- collisions in the range sqrt(s)~2-200 GeV to the NMLLA+NLO* predictions allow one to extract a value of the QCD parameter Lambda_QCD, and associated two-loop coupling constant at the Z resonance alpha_s(m_Z^2)= 0.1195 +/- 0.0022, in excellent numerical agreement with the current world average obtained using other methods.

  3. Plio-Pleistocene extinctions and immigration credit reflected in the size-frequency distribution of Mediterranean marine bivalves

    Science.gov (United States)

    Nawrot, Rafal; Zuschin, Martin; Chattopadhyay, Devapriya

    2015-04-01

    Following the opening of the Suez Canal hundreds of Red Sea species have entered the Mediterranean Sea making it a global hot spot of marine bioinvasion. With the ongoing influx of the subtropical and tropical alien species and increasing sea surface temperatures, the Mediterranean biota is currently gaining a more tropical character and increasingly becoming a mixture of faunal stocks with different evolutionary histories. This susceptibility to invasion was suggested to reflect the presence of an empty ecological space left after decimation of incumbent warm-water fauna during Plio-Pleistocene climate fluctuations. As molluscs are among the most prolific immigrants, we test this hypothesis using data on taxonomic composition and body size of Pliocene Mediterranean bivalves derived from the literature sources and museum collections. The Pliocene inter-specific size-frequency distribution (SFD) is strikingly similar to the SFDs of the Recent Red Sea bivalve fauna, in spite of different biogeographic provenance and the absence of true reef ecosystems in the Pliocene of the Mediterranean region. In contrast, body-size patterns in both assemblages are significantly different from the present-day Mediterranean fauna characterized by smaller median and modal size. Our preliminary results suggest that the distinct shape of the modern Mediterranean SFD may reflect the selective nature of the late Piacenzian - Galesian (Late Pliocene - Early Pleistocene) extinctions pulses related to the onset of the Northern Hemisphere glaciations. These extinctions affected almost 40% of Pliocene species and were biased towards large-bodied taxa. They were not followed by re-immigration of warm-water species owing to the isolation from the tropical Atlantic biota by the cold upwelling along the NW coasts of Africa. The resulting invasion credit (sensu Jackson & Sax, 2010) is currently being paid by the Red Sea bivalves colonizing the Mediterranean Sea through the Suez Canal. Successful

  4. Taxonomic key for the genera of Elmidae (Coleoptera, Byrrhoidea occurring in Goiás State, Brazil, including new records and distributional notes

    Directory of Open Access Journals (Sweden)

    Felipe F. Barbosa

    2013-06-01

    Full Text Available A taxonomic key for the genera of Elmidae (Coleoptera, Byrrhoidea occurring in Goiás State, Brazil, including new records and distributional notes. Despite their great diversity and high abundance in Neotropical aquatic environments, the fauna of Elmidae remains practically unknown in some areas and even entire biomes in this region. In this work we bring, for the first time, faunistic data for the Elmidae of central Brazil. The aim of this work was to inventory the Elmidae fauna in central, southwestern and southeastern Goiás State, Brazil and to produce a taxonomic key, at genus level, for adults from the studied region. The taxonomic key presented herein offers means for the identification of all the 13 genera known to occur in Goiás, 11 of them being new records for the State. Moreover, the number of named species registered for Goiás increased from one to nine.

  5. Spatiotemporal distribution of low-frequency earthquakes in Southwest Japan: Evidence for fluid migration and magmatic activity

    Science.gov (United States)

    Yu, Zhiteng; Zhao, Dapeng; Niu, Xiongwei; Li, Jiabiao

    2018-01-01

    Low-frequency earthquakes (LFEs) in the lower crust and uppermost mantle are widely observed in Southwest Japan, and they occur not only along the subducting Philippine Sea (PHS) slab interface but also beneath active arc volcanoes. The volcanic LFEs are still not well understood because of their limited quantities and less reliable hypocenter locations. In this work, seismic tomography is used to determine detailed three-dimensional (3-D) P- and S-wave velocity (Vp and Vs) models of the crust and upper mantle beneath Southwest Japan, and then the obtained 3-D Vp and Vs models are used to relocate the volcanic LFEs precisely. The results show that the volcanic LFEs can be classified into two types: pipe-like and swarm-like LFEs, and both of them are located in or around zones of low-velocity and high-Poisson's ratio anomalies in the crust and uppermost mantle beneath the active volcanoes. The pipe-like LFEs may be related to the fluid migration from the lower crust or the uppermost mantle, whereas the swarm-like LFEs may be related to local magmatic activities or small magma chambers. The number of LFEs sometimes increases sharply before or after a nearby large crustal earthquake which may cause cracks and fluid migration. The spatiotemporal distribution of the LFEs may indicate the track of migrating fluids. As compared with the tectonic LFEs along the PHS slab interface, the volcanic LFEs are more sensitive to fluid migration and local magmatic activities. High pore pressures play an important role in triggering both types of LFEs in Southwest Japan.

  6. Detection of sputum by interpreting the time-frequency distribution of respiratory sound signal using image processing techniques.

    Science.gov (United States)

    Niu, Jinglong; Shi, Yan; Cai, Maolin; Cao, Zhixin; Wang, Dandan; Zhang, Zhaozhi; Zhang, Xiaohua Douglas

    2018-03-01

    Sputum in the trachea is hard to expectorate and detect directly for the patients who are unconscious, especially those in Intensive Care Unit. Medical staff should always check the condition of sputum in the trachea. This is time-consuming and the necessary skills are difficult to acquire. Currently, there are few automatic approaches to serve as alternatives to this manual approach. We develop an automatic approach to diagnose the condition of the sputum. Our approach utilizes a system involving a medical device and quantitative analytic methods. In this approach, the time-frequency distribution of respiratory sound signals, determined from the spectrum, is treated as an image. The sputum detection is performed by interpreting the patterns in the image through the procedure of preprocessing and feature extraction. In this study, 272 respiratory sound samples (145 sputum sound and 127 non-sputum sound samples) are collected from 12 patients. We apply the method of leave-one out cross-validation to the 12 patients to assess the performance of our approach. That is, out of the 12 patients, 11 are randomly selected and their sound samples are used to predict the sound samples in the remaining one patient. The results show that our automatic approach can classify the sputum condition at an accuracy rate of 83.5%. The matlab codes and examples of datasets explored in this work are available at Bioinformatics online. yesoyou@gmail.com or douglaszhang@umac.mo. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  7. Application of a frequency distribution method for determining instars of the beet armyworm (Lepidoptera: Noctuidae) from widths of cast head capsules

    Science.gov (United States)

    Y. Chen; S. J. Seybold

    2013-01-01

    Instar determination of field-collected insect larvae has generally been based on the analysis of head capsule width frequency distributions or bivariate plotting, but few studies have tested the validity of such methods. We used head capsules from exuviae of known instars of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae),...

  8. Associative memory storing an extensive number of patterns based on a network of oscillators with distributed natural frequencies in the presence of external white noise

    Science.gov (United States)

    Yoshioka, Masahiko; Shiino, Masatoshi

    2000-05-01

    We study associative memory based on temporal coding in which successful retrieval is realized as an entrainment in a network of simple phase oscillators with distributed natural frequencies under the influence of white noise. The memory patterns are assumed to be given by uniformly distributed random numbers on [0, 2π) so that the patterns encode the phase differences of the oscillators. To derive the macroscopic order parameter equations for the network with an extensive number of stored patterns, we introduce an effective transfer function by assuming a fixed-point equation of the form of the Thouless-Anderson-Palmer equation, which describes the time-averaged output as a function of the effective time-averaged local field. Properties of the networks associated with synchronization phenomena for a discrete symmetric natural frequency distribution with three frequency components are studied based on the order parameter equations, and are shown to be in good agreement with the results of numerical simulations. Two types of retrieval states are found to occur with respect to the degree of synchronization, when the size of the width of the natural frequency distribution is changed.

  9. A distributed model predictive control based load frequency control scheme for multi-area interconnected power system using discrete-time Laguerre functions.

    Science.gov (United States)

    Zheng, Yang; Zhou, Jianzhong; Xu, Yanhe; Zhang, Yuncheng; Qian, Zhongdong

    2017-05-01

    This paper proposes a distributed model predictive control based load frequency control (MPC-LFC) scheme to improve control performances in the frequency regulation of power system. In order to reduce the computational burden in the rolling optimization with a sufficiently large prediction horizon, the orthonormal Laguerre functions are utilized to approximate the predicted control trajectory. The closed-loop stability of the proposed MPC scheme is achieved by adding a terminal equality constraint to the online quadratic optimization and taking the cost function as the Lyapunov function. Furthermore, the treatments of some typical constraints in load frequency control have been studied based on the specific Laguerre-based formulations. Simulations have been conducted in two different interconnected power systems to validate the effectiveness of the proposed distributed MPC-LFC as well as its superiority over the comparative methods. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Nanostructures for very broadband or multi-frequency transition from wave beams to a subwavelength light distributions

    OpenAIRE

    Luukkonen, O.; Pniewski, J.; Simovski, C.

    2011-01-01

    In this paper we suggest and theoretically study a tapered plasmonic nanostructure which connects the incident wave beam with a subwavelength spatial region where the field is locally enhanced in a broad frequency range or for different operation frequencies. This spatial region has a frequency stable location near the contour of the tapered structure. This results from a special waveguide mode which can also exist in the tapered structure. We foresee many possible applications for our struct...

  11. SBRT of lung tumours: Monte Carlo simulation with PENELOPE of dose distributions including respiratory motion and comparison with different treatment planning systems

    Science.gov (United States)

    Panettieri, Vanessa; Wennberg, Berit; Gagliardi, Giovanna; Amor Duch, Maria; Ginjaume, Mercè; Lax, Ingmar

    2007-07-01

    The purpose of this work was to simulate with the Monte Carlo (MC) code PENELOPE the dose distribution in lung tumours including breathing motion in stereotactic body radiation therapy (SBRT). Two phantoms were modelled to simulate a pentagonal cross section with chestwall (unit density), lung (density 0.3 g cm-3) and two spherical tumours (unit density) of diameters respectively of 2 cm and 5 cm. The phase-space files (PSF) of four different SBRT field sizes of 6 MV from a Varian accelerator were calculated and used as beam sources to obtain both dose profiles and dose-volume histograms (DVHs) in different volumes of interest. Dose distributions were simulated for five beams impinging on the phantom. The simulations were conducted both for the static case and including the influence of respiratory motion. To reproduce the effect of breathing motion different simulations were performed keeping the beam fixed and displacing the phantom geometry in chosen positions in the cranial and caudal and left-right directions. The final result was obtained by combining the different position with two motion patterns. The MC results were compared with those obtained with three commercial treatment planning systems (TPSs), two based on the pencil beam (PB) algorithm, the TMS-HELAX (Nucletron, Sweden) and Eclipse (Varian Medical System, Palo Alto, CA), and one based on the collapsed cone algorithm (CC), Pinnacle3 (Philips). Some calculations were also carried out with the analytical anisotropic algorithm (AAA) in the Eclipse system. All calculations with the TPSs were performed without simulated breathing motion, according to clinical practice. In order to compare all the TPSs and MC an absolute dose calibration in Gy/MU was performed. The analysis shows that the dose (Gy/MU) in the central part of the gross tumour volume (GTV) is calculated for both tumour sizes with an accuracy of 2-3% with PB and CC algorithms, compared to MC. At the periphery of the GTV the TPSs overestimate

  12. Origin of discrepancies between crater size-frequency distributions of coeval lunar geologic units via target property contrasts

    Science.gov (United States)

    van der Bogert, C. H.; Hiesinger, H.; Dundas, C. M.; Krüger, T.; McEwen, A. S.; Zanetti, M.; Robinson, M. S.

    2017-12-01

    Recent work on dating Copernican-aged craters, using Lunar Reconnaissance Orbiter (LRO) Camera data, re-encountered a curious discrepancy in crater size-frequency distribution (CSFD) measurements that was observed, but not understood, during the Apollo era. For example, at Tycho, Copernicus, and Aristarchus craters, CSFDs of impact melt deposits give significantly younger relative and absolute model ages (AMAs) than impact ejecta blankets, although these two units formed during one impact event, and would ideally yield coeval ages at the resolution of the CSFD technique. We investigated the effects of contrasting target properties on CSFDs and their resultant relative and absolute model ages for coeval lunar impact melt and ejecta units. We counted craters with diameters through the transition from strength- to gravity-scaling on two large impact melt deposits at Tycho and King craters, and we used pi-group scaling calculations to model the effects of differing target properties on final crater diameters for five different theoretical lunar targets. The new CSFD for the large King Crater melt pond bridges the gap between the discrepant CSFDs within a single geologic unit. Thus, the observed trends in the impact melt CSFDs support the occurrence of target property effects, rather than self-secondary and/or field secondary contamination. The CSFDs generated from the pi-group scaling calculations show that targets with higher density and effective strength yield smaller crater diameters than weaker targets, such that the relative ages of the former are lower relative to the latter. Consequently, coeval impact melt and ejecta units will have discrepant apparent ages. Target property differences also affect the resulting slope of the CSFD, with stronger targets exhibiting shallower slopes, so that the final crater diameters may differ more greatly at smaller diameters. Besides their application to age dating, the CSFDs may provide additional information about the

  13. On the relation between activity-related frequency shifts and the sunspot distribution over the solar cycle 23

    Directory of Open Access Journals (Sweden)

    Santos Ângela R. G.

    2017-01-01

    Full Text Available The activity-related variations in the solar acoustic frequencies have been known for 30 years. However, the importance of the different contributions is still not well established. With this in mind, we developed an empirical model to estimate the spot-induced frequency shifts, which takes into account the sunspot properties, such as area and latitude. The comparison between the model frequency shifts obtained from the daily sunspot records and those observed suggests that the contribution from a stochastic component to the total frequency shifts is about 30%. The remaining 70% is related to a global, long-term variation. We also propose a new observable to investigate the short-and mid-term variations of the frequency shifts, which is insensitive to the long-term variations contained in the data. On the shortest time scales the variations in the frequency shifts are strongly correlated with the variations in the total area covered by sunspots. However, a significant loss of correlation is still found, which cannot be fully explained by ignoring the invisible side of the Sun when accounting for the total sunspot area. We also verify that the times when the frequency shifts and the sunspot areas do not vary in a similar way tend to coincide with the times of the maximum amplitude of the quasi-biennial variations found in the seismic data.

  14. Energy storage systems impact on the short-term frequency stability of distributed autonomous microgrids, an analysis using aggregate models

    DEFF Research Database (Denmark)

    Serban, Ioan; Teodorescu, Remus; Marinescu, Corneliu

    2013-01-01

    This study analyses the integration impact of battery energy storage systems (BESSs) on the short-term frequency control in autonomous microgrids (MGs). Short-term frequency stability relates with the primary or speed control level, as defined in the regulations of the classical grids. The focus...... with both inertial response and an adaptive droop characteristic during battery state-of-charge limitations. The conducted analysis is accomplished by adopting aggregated models for the involved control mechanisms. The developed model is analysed in frequency domain, whereas an experimental test bench...

  15. Analysis of Maneuvering Targets with Complex Motions by Two-Dimensional Product Modified Lv’s Distribution for Quadratic Frequency Modulation Signals

    Directory of Open Access Journals (Sweden)

    Fulong Jing

    2017-06-01

    Full Text Available For targets with complex motion, such as ships fluctuating with oceanic waves and high maneuvering airplanes, azimuth echo signals can be modeled as multicomponent quadratic frequency modulation (QFM signals after migration compensation and phase adjustment. For the QFM signal model, the chirp rate (CR and the quadratic chirp rate (QCR are two important physical quantities, which need to be estimated. For multicomponent QFM signals, the cross terms create a challenge for detection, which needs to be addressed. In this paper, by employing a novel multi-scale parametric symmetric self-correlation function (PSSF and modified scaled Fourier transform (mSFT, an effective parameter estimation algorithm is proposed—referred to as the Two-Dimensional product modified Lv’s distribution (2D-PMLVD—for QFM signals. The 2D-PMLVD is simple and can be easily implemented by using fast Fourier transform (FFT and complex multiplication. These measures are analyzed in the paper, including the principle, the cross term, anti-noise performance, and computational complexity. Compared to the other three representative methods, the 2D-PMLVD can achieve better anti-noise performance. The 2D-PMLVD, which is free of searching and has no identifiability problems, is more suitable for multicomponent situations. Through several simulations and analyses, the effectiveness of the proposed estimation algorithm is verified.

  16. Allele frequency distribution of CYP2C9 2 and CYP2C9 3 polymorphisms in six Mexican populations.

    Science.gov (United States)

    Castelán-Martínez, Osvaldo D; Hoyo-Vadillo, Carlos; Sandoval-García, Emmanuel; Sandoval-Ramírez, Lucila; González-Ibarra, Miriam; Solano-Solano, Gloria; Gómez-Díaz, Rita A; Parra, Esteban J; Cruz, Miguel; Valladares-Salgado, Adán

    2013-07-10

    Allele frequency differences of functional CYP2C9 polymorphisms are responsible for some of the variation in drug response observed in human populations. The most relevant CYP2C9 functional variants are CYP2C9*2 (rs1799853) and CYP2C9 3 (rs1057910). These polymorphisms show variation in allele frequencies among different population groups. The present study aimed to analyze these polymorphisms in 947 Mexican-Mestizo from Mexico City and 483 individuals from five indigenous Mexican populations: Nahua, Teenek, Tarahumara, Purepecha and Huichol. The CYP2C9*2 allele frequencies in the Mestizo, Nahua and Teenek populations were 0.051, 0.007 and 0.005, respectively. As for CYP2C9 3, the allelic frequencies in the Mestizo, Nahua and Teenek populations were 0.04, 0.005 and 0.005, respectively. The CYP2C9 2 and CYP2C9 3 alleles were not observed in the Tarahumara, Purepecha and Huichol populations. These findings are in agreement with previous studies reporting very low allele frequencies for these polymorphisms in American Indigenous populations. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Effects of flood frequency and duration on the allometry of community-level stem size-density distributions in a floodplain forest.

    Science.gov (United States)

    De Jager, Nathan R

    2012-09-01

    Consistent with the self-thinning law of plant population ecology, Niklas et al. in 2003 proposed that stem size-density distributions (SDDs) of multispecies forest communities should change in very predictable ways as a function of the effects of past disturbances on average tree size. To date, empirical tests of this hypothesis have not been pursued in floodplain settings. SDDs were constructed using tree stem-size and density data from forest plots positioned along a flood frequency and duration gradient in the Upper Mississippi River floodplain. As flooding (both frequency and duration) increased, several small tree species were eliminated from forest plots and the persistent species increased in their size. Consistent with the predictions of Niklas et al., these changes corresponded with overall decreases in stem density, increases in average stem size, and reductions in both the Y-intercept and slope terms of the community-level SDDs. This study adds to a growing list of examples suggesting that theories related to forest community composition and biomass must account for both the broader effects of disturbances as well as the underlying biochemical processes that regulate plant growth. Further study is needed to fully address the role different disturbance frequencies play in determining plant density, diversity, average size, and associated size\\frequency distributions.

  18. MULTI-FREQUENCY OSCILLATORY VENTILATION IN THE PREMATURE LUNG: EFFECTS ON GAS EXCHANGE, MECHANICS, AND VENTILATION DISTRIBUTION

    Science.gov (United States)

    Kaczka, David W.; Herrmann, Jacob; Zonneveld, C. Elroy; Tingay, David G.; Lavizzari, Anna; Noble, Peter B.; Pillow, J. Jane

    2015-01-01

    Background Despite the theoretical benefits of high-frequency oscillatory ventilation (HFOV) in preterm infants, systematic reviews of randomized clinical trials do not confirm improved outcomes. We hypothesized that oscillating a premature lung with multiple frequencies simultaneously would improve gas exchange compared to traditional single-frequency oscillatory ventilation (SFOV). The goal of this study was to develop a novel method for HFOV, termed ‘multi-frequency oscillatory ventilation’ (MFOV), which relies on a broadband flow waveform more suitable for the heterogeneous mechanics of the immature lung. Methods Thirteen intubated preterm lambs were randomized to either SFOV or MFOV for 1 hour, followed by crossover to the alternative regimen for 1 hour. The SFOV waveform consisted of a pure sinusoidal flow at 5 Hz, while the customized MFOV waveform consisted of a 5 Hz fundamental with additional energy at 10 and 15 Hz. Per standardized protocol, mean pressure at airway opening (P̅ao) and inspired O2 fraction were adjusted as needed, and root mean square of the delivered oscillatory volume waveform (Vrms) was adjusted 15-minute intervals. A ventilatory cost function for SFOV and MFOV was defined as VC=(Vrms2PaCO2)Wt−1, where Wt denotes body weight. Results Averaged over all time points, MFOV resulted in significantly lower VC (246.9±6.0 vs. 363.5±15.9 mL2 mmHg kg−1) and P̅ao (12.8±0.3 vs. 14.1±0.5 cmH2O) compared to SFOV, suggesting more efficient gas exchange and enhanced lung recruitment at lower mean airway pressures. Conclusions Oscillation with simultaneous multiple frequencies may be a more efficient ventilator modality in premature lungs compared to traditional single-frequency HFOV. PMID:26495977

  19. A Theoretical Study and Numerical Simulation of a Quasi-Distributed Sensor Based on the Low-Finesse Fabry-Perot Interferometer: Frequency-Division Multiplexing.

    Science.gov (United States)

    Guillen Bonilla, José Trinidad; Guillen Bonilla, Alex; Rodríguez Betancourtt, Verónica M; Guillen Bonilla, Héctor; Casillas Zamora, Antonio

    2017-04-14

    The application of the sensor optical fibers in the areas of scientific instrumentation and industrial instrumentation is very attractive due to its numerous advantages. In the industry of civil engineering for example, quasi-distributed sensors made with optical fiber are used for reliable strain and temperature measurements. Here, a quasi-distributed sensor in the frequency domain is discussed. The sensor consists of a series of low-finesse Fabry-Perot interferometers where each Fabry-Perot interferometer acts as a local sensor. Fabry-Perot interferometers are formed by pairs of identical low reflective Bragg gratings imprinted in a single mode fiber. All interferometer sensors have different cavity length, provoking frequency-domain multiplexing. The optical signal represents the superposition of all interference patterns which can be decomposed using the Fourier transform. The frequency spectrum was analyzed and sensor's properties were defined. Following that, a quasi-distributed sensor was numerically simulated. Our sensor simulation considers sensor properties, signal processing, noise system, and instrumentation. The numerical results show the behavior of resolution vs. signal-to-noise ratio. From our results, the Fabry-Perot sensor has high resolution and low resolution. Both resolutions are conceivable because the Fourier Domain Phase Analysis (FDPA) algorithm elaborates two evaluations of Bragg wavelength shift.

  20. Survey and analysis of microsatellites from transcript sequences in Phytophthora species: frequency, distribution, and potential as markers for the genus

    Directory of Open Access Journals (Sweden)

    Barreto Emiliano

    2006-09-01

    Full Text Available Abstract Background Members of the genus Phytophthora are notorious pathogens with world-wide distribution. The most devastating species include P. infestans, P. ramorum and P. sojae. In order to develop molecular methods for routinely characterizing their populations and to gain a better insight into the organization and evolution of their genomes, we used an in silico approach to survey and compare simple sequence repeats (SSRs in transcript sequences from these three species. We compared the occurrence, relative abundance, relative density and cross-species transferability of the SSRs in these oomycetes. Results The number of SSRs in oomycetes transcribed sequences is low and long SSRs are rare. The in silico transferability of SSRs among the Phytophthora species was analyzed for all sets generated, and primers were selected on the basis of similarity as possible candidates for transferability to other Phytophthora species. Sequences encoding putative pathogenicity factors from all three Phytophthora species were also surveyed for presence of SSRs. However, no correlation between gene function and SSR abundance was observed. The SSR survey results, and the primer pairs designed for all SSRs from the three species, were deposited in a public database. Conclusion In all cases the most common SSRs were trinucleotide repeat units with low repeat numbers. A proportion (7.5% of primers could be transferred with 90% similarity between at least two species of Phytophthora. This information represents a valuable source of molecular markers for use in population genetics, genetic mapping and strain fingerprinting studies of oomycetes, and illustrates how genomic databases can be exploited to generate data-mining filters for SSRs before experimental validation.

  1. Characteristics of Carrier Transport and Crystallographic Orientation Distribution of Transparent Conductive Al-Doped ZnO Polycrystalline Films Deposited by Radio-Frequency, Direct-Current, and Radio-Frequency-Superimposed Direct-Current Magnetron Sputtering.

    Science.gov (United States)

    Nomoto, Junichi; Inaba, Katsuhiko; Kobayashi, Shintaro; Watanabe, Takeshi; Makino, Hisao; Yamamoto, Tetsuya

    2017-08-09

    We investigated the characteristics of carrier transport and crystallographic orientation distribution in 500-nm-thick Al-doped ZnO (AZO) polycrystalline films to achieve high-Hall-mobility AZO films. The AZO films were deposited on glass substrates at 200 °C by direct-current, radio-frequency, or radio-frequency-superimposed direct-current magnetron sputtering at various power ratios. We used sintered AZO targets with an Al₂O₃ content of 2.0 wt. %. The analysis of the data obtained by X-ray diffraction, Hall-effect, and optical measurements of AZO films at various power ratios showed that the complex orientation texture depending on the growth process enhanced the contribution of grain boundary scattering to carrier transport and of carrier sinks on net carrier concentration, resulting in the reduction in the Hall mobility of polycrystalline AZO films.

  2. Experiences with non-intrusive monitoring of distribution transformers based on the on-line frequency response

    Directory of Open Access Journals (Sweden)

    Eduardo Gomez Luna

    2015-01-01

    Full Text Available The following article presents the results obtained in experiences that use the Impulse Frequency Response Analysis (IFRA method with a transformer in service. The IFRA method has been implemented in order to transform the transient signals to the frequency domain using Discrete Fourier Transform (DFT. However, it can be considered that the DFT is not the most suitable tool for this type of analysis, since, by definition, this tool is useful for processing stationary signals. Taking that into consideration, the analysis of transient signals could be hypothetically improved by using continuous wavelet transform (CWT, given their variable time/frequency resolution. The analysis of transient signals in Wavelet domain has improved the repeatability of the frequency response curves, as it has been ob-served in experimental results. The proposed on-line IFRA method, based on Wavelet transform, was validated under load and no-load conditions on a 150 kVA three-phase transformer 13200/225 Volts, in the Campus of the Universidad del Valle, Cali, Colombia.

  3. A Corpus-Based Lexical Study on Frequency and Distribution of Coxhead's Awl Word Families in Medical Research Articles (RAs)

    Science.gov (United States)

    Chen, Qi; Guang-Chun, Ge

    2007-01-01

    We conducted a lexical study on the word frequency and the text coverage of the 570 word families from Coxhead's Academic Word List (AWL) in medical research articles (RAs) based on a corpus of 50 medical RAs written in English with 190425 running words. By computer analysis, we found that the text coverage of the AWL words accounted for around…

  4. State updating of a distributed hydrological model with Ensemble Kalman Filtering: effects of updating frequency and observation network density on forecast accuracy

    Directory of Open Access Journals (Sweden)

    O. Rakovec

    2012-09-01

    Full Text Available This paper presents a study on the optimal setup for discharge assimilation within a spatially distributed hydrological model. The Ensemble Kalman filter (EnKF is employed to update the grid-based distributed states of such an hourly spatially distributed version of the HBV-96 model. By using a physically based model for the routing, the time delay and attenuation are modelled more realistically. The discharge and states at a given time step are assumed to be dependent on the previous time step only (Markov property.

    Synthetic and real world experiments are carried out for the Upper Ourthe (1600 km2, a relatively quickly responding catchment in the Belgian Ardennes. We assess the impact on the forecasted discharge of (1 various sets of the spatially distributed discharge gauges and (2 the filtering frequency. The results show that the hydrological forecast at the catchment outlet is improved by assimilating interior gauges. This augmentation of the observation vector improves the forecast more than increasing the updating frequency. In terms of the model states, the EnKF procedure is found to mainly change the pdfs of the two routing model storages, even when the uncertainty in the discharge simulations is smaller than the defined observation uncertainty.

  5. Spatial and Temporal Analysis on the Distribution of Active Radio-Frequency Identification (RFID) Tracking Accuracy with the Kriging Method

    OpenAIRE

    Liu, Xin; Shannon, Jeremy; Voun, Howard; Truijens, Martijn; Chi, Hung-Lin; Wang, Xiangyu

    2014-01-01

    Radio frequency identification (RFID) technology has already been applied in a number of areas to facilitate the tracking process. However, the insufficient tracking accuracy of RFID is one of the problems that impedes its wider application. Previous studies focus on examining the accuracy of discrete points RFID, thereby leaving the tracking accuracy of the areas between the observed points unpredictable. In this study, spatial and temporal analysis is applied to interpolate the continuous d...

  6. Evaluation of Distributive Frequency of Oral Contraceptive Pills Consumption in Women with Cerebrovascular Events Admitted in Farshchian Hospital of Hamadan between 1997-2007

    Directory of Open Access Journals (Sweden)

    Mehrdokht Mazdeh

    2011-06-01

    Full Text Available Background & Objectives: Although there is no prolonged time elapsed from propagation of oral contraceptive pills (OCP, case reports demonstrated occurrence of pulmonary embolism and cerebral infarction in women using these pills. Present study was done to specify distributive frequency of oral contraceptive pills consumption in women with cerebrovascular events admitted in Farshchian hospital of Hamadan between 1997 to 2007. Materials & Methods: Every woman with cerebrovascular events during years 1997-2007 who was admitted in Farshchian hospital of Hamadan and her dossier was present in archive of hospital, were carefully checked and those who hadn’t exclusion criteria, were include in this study, a total of 1587 of them with respect to their Characteristics such as type of cerebrovascular event, age, type of oral contraceptive pill and duration of pill use were extracted from patient dossier and registered in respective checklist. Results: 24.1% of patient used oral contraceptive pill and 76.9% of patients were non users. Mean age of OCP users and non users were 45 years. Mean duration of pill use among these patients was 33 months. In assessing type of vascular events, in the group OCP users 73.1% and non users 66.4% had ischemic stroke.Which was statistically significant. In the group OCP users 24.6% and non users 29.1% were hemorrhagic stroke.. Also in the group OCP users 2.3% and non users 4.5% were affected sagital sinuses thrombosis that showed no significant difference. Among OCP users 85% of the patients used OCP, LD and 15% of the patients OCP, HD. Conclusion: The present study showed, the ischemic stroke rate of the patients with OCP consumption were significantly more than those of non users.

  7. Magnitude-frequency and Spatial Distribution of Rockfalls in the White Canyon, British Columbia using Terrestrial LiDAR and Microseismic Monitoring Systems

    Science.gov (United States)

    van Veen, M.

    2015-12-01

    Transportation corridors built along natural slopes are subject to frequent rockfall hazards, which can disrupt service and cause damage to infrastructure. Many of these areas exist along the Fraser-Thompson corridor of the CN rail line in Southern British Columbia, particularly in the White Canyon area near Lytton. Here the rail track is situated between the 500 m high slopes and the river, for 2.4 km. The frequency-magnitude relationship between these events and the percentage of rockfalls making it to track level are important components of hazard assessment for these slopes. Traditional methods of collecting rockfall data in this area involve visual inspection by maintenance personnel, however this is an onerous task for such a large slope with frequent rockfall activity, and therefore the rockfall record for this area is often lacking data. Since 2012, high-resolution terrestrial LiDAR (Light detection and ranging) data has been collected for the White Canyon area and analysis of change from sequential LiDAR scans provides detailed data that can't be obtained from traditional rockfall databases, including the magnitude and spatial distribution of rockfall events. While the LiDAR change detection can be useful in identifying rockfall volumes and source zones, it can be difficult to determine the end location of each rockfall and the exact timing of events, as scan data is usually collected over a period of several months. Recently, a microseismic monitoring system has been deployed over a section of the railway track and data is available on time and location of impact at the track level, which permits assessment of the number of rockfalls traversing the whole slope down to track level. This, in combination with data on rockfall magnitudes and source zones obtained from the LiDAR change detection can provide useful information for management of tracks in these hazardous settings and also provides data for calibration of rockfall modelling.

  8. Preliminary survey on the distribution of medical equipment and frequency of diagnostic and therapeutic procedures in Brazil: a contribution to the UNSCEAR report

    International Nuclear Information System (INIS)

    Biazotto, Bruna; Taboza de Oliveira, Alexandre; Baptista de Freitas, Marcelo

    2008-01-01

    Information about Brazil published in the UNSCEAR 2000 report are still scarce when compared to others countries. In this study, a survey on the distribution of medical equipment (X-ray generators, ultrasound, CT and MRI scanners, nuclear medicine equipment and teletherapy and brachytherapy units) and frequency of diagnostic and therapeutic procedures at the various Brazilian States was carried out. The overall information was obtained from a national database supported by the Brazilian Ministry of Health through the Computer Science Department of the National Health System (SUS - Sistema Unico de Saude). The distribution of equipment and the annual frequency of each type of procedure were analyzed considering the five geographical regions that form the country and their respective population. Temporal and regional trends in the annual frequency of procedures for 2000-2007 were also summarized in this study. National annual frequencies for the total of all medical X-ray examinations (259.0 examinations per 1000 population) were evaluated. Some examples can be given from chest, mammography and CT examinations: 67.4, 30.2 and 7.2 per 1000 population, respectively. In addition, annual frequencies for other modalities of diagnostic imaging have also been estimated: 61.5, 1.6 and 1.4 per 1000 population for ultrasound, nuclear medicine and MRI procedures, respectively. A total of 38.7 therapeutic procedures per 1000 population (teletherapy and brachytherapy) are annually performed in the country. The health services localized in Brazil comprised a total number of 253.1 diagnostic imaging equipment per million population, without considering dental X-ray. Amongst them, X-ray equipment used in common radiological examinations (chest, skull, spine, etc.) stands for 39% (97.7 per million). As expected, a significant decrease in the offer of equipment is observed when technologically more sophisticated equipment is concerned: magnetic resonance (3.5 per million), gamma

  9. Distribution and frequency of Bru1, a major brown rust resistance gene, in the sugarcane world collection

    Science.gov (United States)

    Brown rust, caused by Puccinia melanocephala, is an important disease of sugarcane worldwide. Molecular markers for a major brown rust resistance gene, Bru1, were used to screen a total of 1,282 clones in the World Collection of Sugarcane and Related Grasses (WCSRG) to determine the distribution and...

  10. Comparative analysis of the frequency, distribution and population sizes of yeasts associated with canine seborrheic dermatitis and healthy skin.

    Science.gov (United States)

    Yurayart, Chompoonek; Chindamporn, Ariya; Suradhat, Sanipa; Tummaruk, Padet; Kajiwara, Susumu; Prapasarakul, Nuvee

    2011-03-24

    The purpose of this study was to investigate the diversity of yeast associated with the degree of canine seborrheic dermatitis (SD) by anatomical sites. Fifty-seven samples were divided as 17 healthy skin, 20 with primary seborrheic dermatitis (PSD), and 20 with secondary seborrheic dermatitis (SSD). Yeast isolation and characterization were carried out based on microscopical features and biochemical properties. DNA analysis at the internal transcribed spacer I of 26S rDNA region was utilized for species confirmation. Four species of yeast consisting Malassezia pachydermatis, Malassezia furfur, Candida parapsilosis and Candida tropicalis recovered from examined dogs. M. pachydermatis and C. parapsilosis were isolated from all dogs, but C. tropicalis and M. furfur were recovered from 3 healthy dogs and one diseased dog, respectively. The number of M. pachydermatis and C. parapsilosis in diseased dogs was higher than that of healthy specimens (P<0.01). High frequency and population size of C. parapsilosis were closely associated to PSD, while those of M. pachydermatis were associated with both PSD and SSD (P<0.01). C. parapsilosis were predominant at the perianal area. This study demonstrated the co-colonization of M. pachydermatis and C. parapsilosis in large amounts and frequency associated with stage of disease and anatomical site. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Plasminogen Activator Inhibitor-1 (PAI-1) gene 4G/5G alleles frequency distribution in the Lebanese population.

    Science.gov (United States)

    Shammaa, Dina M R; Sabbagh, Amira S; Taher, Ali T; Zaatari, Ghazi S; Mahfouz, Rami A R

    2008-09-01

    Plasminogen activator inhibitor-1 (PAI-1) is an inhibitor of fibrinolysis. Increased plasma PAI-1 levels play an essential role in the pathogenesis of cardiovascular risk and other diseases associated with thrombosis. The 4G/5G polymorphism of the PAI-1 promoter region has been extensively studied in different populations. We studied 160 healthy unrelated Lebanese individuals using a reverse hybridization PCR assay to detect the 5G/5G, 4G/5G and, 4G/4G genotypes of the PAI-1 gene and the frequencies of the 4G and 5G alleles. We found that 4G/5G genotype was the most prevalent (45.6%) followed by 5G/5G (36.9%) and 4G/4G (17.5%). The frequencies of the 4G and 5G alleles were calculated to be 0.403 and 0.597, respectively. Compared to other ethnic communities, the Lebanese population was found to harbour a relatively high prevalence of the rare 4G allele. This, in turn, may predispose this population to develop cardiovascular diseases and other thrombotic clinical conditions. This study aids to enhance our understanding of the genetic features of the Lebanese population.

  12. Disturbance frequency and vertical distribution of seeds affect long-term population dynamics: a mechanistic seed bank model.

    Science.gov (United States)

    Eager, Eric Alan; Haridas, Chirakkal V; Pilson, Diana; Rebarber, Richard; Tenhumberg, Brigitte

    2013-08-01

    Seed banks are critically important for disturbance specialist plants because seeds of these species germinate only in disturbed soil. Disturbance and seed depth affect the survival and germination probability of seeds in the seed bank, which in turn affect population dynamics. We develop a density-dependent stochastic integral projection model to evaluate the effect of stochastic soil disturbances on plant population dynamics with an emphasis on mimicking how disturbances vertically redistribute seeds within the seed bank. We perform a simulation analysis of the effect of the frequency and mean depth of disturbances on the population's quasi-extinction probability, as well as the long-term mean and variance of the total density of seeds in the seed bank. We show that increasing the frequency of disturbances increases the long-term viability of the population, but the relationship between the mean depth of disturbance and the long-term viability of the population are not necessarily monotonic for all parameter combinations. Specifically, an increase in the probability of disturbance increases the long-term viability of the total seed bank population. However, if the probability of disturbance is too low, a shallower mean depth of disturbance can increase long-term viability, a relationship that switches as the probability of disturbance increases. However, a shallow disturbance depth is beneficial only in scenarios with low survival in the seed bank.

  13. Asian population frequencies and haplotype distribution of killer cell immunoglobulin-like receptor (KIR) genes among Chinese, Malay, and Indian in Singapore.

    Science.gov (United States)

    Lee, Yi Chuan; Chan, Soh Ha; Ren, Ee Chee

    2008-11-01

    Killer cell immunoglobulin-like receptors (KIR) gene frequencies have been shown to be distinctly different between populations and contribute to functional variation in the immune response. We have investigated KIR gene frequencies in 370 individuals representing three Asian populations in Singapore and report here the distribution of 14 KIR genes (2DL1, 2DL2, 2DL3, 2DL4, 2DL5, 2DS1, 2DS2, 2DS3, 2DS4, 2DS5, 3DL1, 3DL2, 3DL3, 3DS1) with two pseudogenes (2DP1, 3DP1) among Singapore Chinese (n = 210); Singapore Malay (n = 80), and Singapore Indian (n = 80). Four framework genes (KIR3DL3, 3DP1, 2DL4, 3DL2) and a nonframework pseudogene 2DP1 were detected in all samples while KIR2DS2, 2DL2, 2DL5, and 2DS5 had the greatest significant variation across the three populations. Fifteen significant linkage patterns, consistent with associations between genes of A and B haplotypes, were observed. Eighty-four distinct KIR profiles were determined in our populations, 38 of which had not been described in other populations. KIR haplotype studies were performed using nine Singapore Chinese families comprising 34 individuals. All genotypes could be resolved into corresponding pairs of existing haplotypes with eight distinct KIR genotypes and eight different haplotypes. The haplotype A2 with frequency of 63.9% was dominant in Singapore Chinese, comparable to that reported in Korean and Chinese Han. The A haplotypes predominate in Singapore Chinese, with ratio of A to B haplotypes of approximately 3:1. Comparison with KIR frequencies in other populations showed that Singapore Chinese shared similar distributions with Chinese Han, Japanese, and Korean; Singapore Indian was found to be comparable with North Indian Hindus while Singapore Malay resembled the Thai.

  14. FREQUENCY AND DISTRIBUTION OF ABO & RH BLOOD GROUP IN BILASPUR DISTRICT OF CHHATTISGARH STATE : A STUDY FROM MEDICAL COLLEGE HOSPITAL

    Directory of Open Access Journals (Sweden)

    Bhanu Pratap

    2015-07-01

    Full Text Available BACKGROUND : Approximate 30 blood group systems have discovered and more than 400 erythrocytes antigens are identified. Blood group ABO and Rh are most important among all other blood group systems in transfusion service practices. The frequency of four major blood gr oup s namely A, B, O, AB with Rh Positive and Negative varies in different population of the world and differ also in region and race wise. MATERIAL AND METHOD : This 5 years retrospective study was conducted at Blood Bank of a Medical college Hospital of Bi laspur in Northern Chhattisgarh, catering the 1/3 population of state. Data were collected from the Blood Bank Grouping record from the period of January 2010 to December 2014. Blood group of blood donors and patients were determined by Monoclonal Anti Ser a by slide agglutinations tests. Rare case and difficult case were examined by test tube agglutination method and Matrix Gel System of Tulip. RESULT AND CONCLUSIO N: 31973 subjects were examined for blood group during observation period, Out of these 31092( 97.25% were male and 881 (2.75% were female. The frequency of blood group B in these populations was 11007 (34.42% (33.36% Rh Positive and 1.06% Rh Negative Followed by O were 10864 (33.97% (33.33% Rh Positive and 0.64% Rh Negative, A was 9113 (28.50 % (27.99 % Rh Positive and 0.51% Rh Negative and AB was 989 (3.11% (3.01% Rh Positive and 0.1% Rh Negative. Rhesus group Rh Positive were 31242 (97.7 % and Rh Negative were 731 (2.3 %.

  15. Ion energy distribution functions in inductively coupled radio-frequency discharges emdash Mixtures of Cl2/BCl3/Ar

    International Nuclear Information System (INIS)

    Nichols, C.A.; Woodworth, J.R.; Hamilton, T.W.

    1998-01-01

    We have used a gridded energy analyzer to measure positive ion energy distributions and fluxes at the grounded electrode of a high-density rf discharge. We present details of ion energies and fluxes in discharges containing mixtures of chlorine, boron trichloride and argon. These feedstock mixtures have been used extensively in the patterning of metal films for semiconductor interconnects. Our experiments were carried out in a Gaseous Electronics Conference Reference Cell which had been modified to produce inductively coupled discharges. The 15-cm-diam bottom electrode was grounded for these experiments. Stainless steel, anodized aluminum, and silicon were used as bottom electrode materials to understand the effects of various chamber boundary conditions on the ion energy parameters. In most cases, the ion energy distributions had a single peak, well separated from zero energy with a 1.0 endash 3.0 eV full width at half maximum. These peaks were typically centered at 12 endash 16 eV, with ion energy increasing as pressure decreased. Addition of BCl 3 to a Cl 2 discharge resulted in a reduction of total ion flux of more than a factor of 2, e.g., from 5 to 2.5 mA/cm 2 (20 mTorr, 200 W). The ion fluxes decreased with increasing pressures in BCl 3 /Cl 2 mixtures, while increasing with pressure in pure Cl 2 discharges. Addition of Ar to several mixtures of BCl 3 /Cl 2 changed the ion fluxes and mean ion energies by less than 15%. At high pressures or low inductive rf powers, the distributions can split into two overlapping peaks separated by as much as 8 eV. This splitting is indicative of capacitive coupling between the rf coil and the discharge. Insertion of a Faraday shield between the coil and the discharge removed most of the splitting. copyright 1998 American Vacuum Society. thinsp

  16. Effect of particle size frequency distribution of the substratum on the burrowing ability of Chiridota rigida (semper) (Echinodermata: holothuroidea)

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, J.M.; Murdoch, J.

    1977-01-01

    Chiridota rigida (Semper) burrows easily into well-sorted substrata, moving between particles in coarse substrata and pushing aside particles in fine substrata. Chiridota rigida does not burrow easily into poorly sorted substrata because spaces which can be penetrated are not available and because the particles cannot be moved as a result of increased stability of the substratum. In poorly sorted substrata, burrowing ability increases with increases in the proportion of fine particles. It would appear that the distribution and abundance of chiridota rigida and other chiridotids would be affected by the effect of the substratum on their ability to burrow.

  17. Distribution Of 15N Fertilizer Added To Sandy Soil Under Drip Irrigation System As Affected By Irrigation Frequencies

    International Nuclear Information System (INIS)

    GADALLA, A.M.; GALAL, Y.G.M.; EL-GENDY, R.W.; ISMAIL, M.M.; EL-DEGWY, S.M.; KASSAB, M.F.

    2009-01-01

    Neutron moisture meter and stable nitrogen isotope ( 15 N) were used to follow horizontal and vertical water movement and N-fertilizer added to soil before and after irrigation. The data indicated that soil moisture distribution and values of total hydraulic potential depend on soil moisture content. Characterization of nitrogen in soil for all sites around the emitter indicated spatial variability with different soil depths due to leaching and volatilization processes. Moreover, water movement and flow direction greatly were characterized by active evaporation depth which was 30 cm.

  18. State updating of a distributed hydrological model with Ensemble Kalman Filtering: Effects of updating frequency and observation network density on forecast accuracy

    Science.gov (United States)

    Rakovec, O.; Weerts, A.; Hazenberg, P.; Torfs, P.; Uijlenhoet, R.

    2012-12-01

    This paper presents a study on the optimal setup for discharge assimilation within a spatially distributed hydrological model (Rakovec et al., 2012a). The Ensemble Kalman filter (EnKF) is employed to update the grid-based distributed states of such an hourly spatially distributed version of the HBV-96 model. By using a physically based model for the routing, the time delay and attenuation are modelled more realistically. The discharge and states at a given time step are assumed to be dependent on the previous time step only (Markov property). Synthetic and real world experiments are carried out for the Upper Ourthe (1600 km2), a relatively quickly responding catchment in the Belgian Ardennes. The uncertain precipitation model forcings were obtained using a time-dependent multivariate spatial conditional simulation method (Rakovec et al., 2012b), which is further made conditional on preceding simulations. We assess the impact on the forecasted discharge of (1) various sets of the spatially distributed discharge gauges and (2) the filtering frequency. The results show that the hydrological forecast at the catchment outlet is improved by assimilating interior gauges. This augmentation of the observation vector improves the forecast more than increasing the updating frequency. In terms of the model states, the EnKF procedure is found to mainly change the pdfs of the two routing model storages, even when the uncertainty in the discharge simulations is smaller than the defined observation uncertainty. Rakovec, O., Weerts, A. H., Hazenberg, P., Torfs, P. J. J. F., and Uijlenhoet, R.: State updating of a distributed hydrological model with Ensemble Kalman Filtering: effects of updating frequency and observation network density on forecast accuracy, Hydrol. Earth Syst. Sci. Discuss., 9, 3961-3999, doi:10.5194/hessd-9-3961-2012, 2012a. Rakovec, O., Hazenberg, P., Torfs, P. J. J. F., Weerts, A. H., and Uijlenhoet, R.: Generating spatial precipitation ensembles: impact of

  19. Particle size distribution in soils and marine sediments by laser diffraction using Malvern Mastersizer 2000—method uncertainty including the effect of hydrogen peroxide pretreatment

    DEFF Research Database (Denmark)

    Callesen, Ingeborg; Keck, Hannes; Andersen, Thorbjørn Joest

    2018-01-01

    Purpose: Methods for particle size distribution (PSD) determination by laser diffraction are not standardized and differ between disciplines and sectors. The effect of H2O2 pretreatment before a sonication treatment in laser diffraction analysis of soils and marine sediments was examined on soils...... with less than 1% C and some marine sediments. Materials and methods: The method uncertainty for particle size analysis by the laser diffraction method using or not using H2O2 pretreatment followed by 2 min ultrasound and 1-mm sieving was determined for two soil samples and two aquatic sediments...... by analyzing ten replicates on a Malvern M2000 instrument. The carbon content was in the normal range for upland soils 0.1–0.9% C, but one of the aquatic sediment samples had a high carbon content (16.3% C) for which the H2O2 pretreatment was not feasible. Results and discussion: The effect of H2O2...

  20. New species of Endecous (Grylloidea, Phalangopsidae, Luzarinae) from the Iguaçu National Park (Brazil), including bioacoustics, cytogenetic and distribution data.

    Science.gov (United States)

    Souza-Dias, Pedro G B; Szinwelski, Neucir; Fianco, Marcos; Oliveira, Elliott Centeno DE; Mello, Francisco DE A G DE; Zefa, Edison

    2017-03-01

    In this study we describe two new species of cavicolous-straminicolous crickets for southern Brazil. Endecous chape n. sp. and E. naipi n. sp. are sympatric crickets that inhabit the Atlantic Semideciduous Forest of the Iguaçu National Park and adjacent areas. The descriptions were based on morphological characters, mainly from male genitalia and tegmina of adult males. Furthermore, we describe the chromosomes and the calling song of one of the new species, E. chape n. sp., presenting a discussion about the morphology of the phallic complex of Endecous and a distribution map for the species of the genus. The type-material is deposited in the Museu de Zoologia da Universidade de São Paulo (MZSP), and in the Coleção de Insetos do Departamento de Zoologia (Zoology Department Insect Collection), Universidade Estadual Paulista-UNESP-Botucatu campus.

  1. Estimating the power-law distribution of Earth electrical conductivity from low-frequency, controlled-source electromagnetic responses

    Science.gov (United States)

    Beskardes, G. D.; Weiss, C. J.; Everett, M. E.

    2017-02-01

    Electromagnetic responses reflect the interaction between applied electromagnetic fields and heterogeneous geoelectrical structures. Quantifying the relationship between multiscale electrical properties and the observed electromagnetic response is therefore important for meaningful geologic interpretation. We present here examples of near-surface electromagnetic responses whose spatial fluctuations appear on all length scales, are repeatable and fractally distributed, supporting the notion of a `rough geology' exhibiting multiscale hierarchical structure. Bounded by end member cases from homogenized isotropic and anisotropic media, we present numerical modelling results of the electromagnetic responses of textured and spatially correlated, stochastic geologic media, demonstrating that the electromagnetic response is a power law distribution, rather than a smooth response polluted with random, incoherent noise as commonly assumed. Our modelling results show that these electromagnetic responses due to spatially correlated geologic textures are examples of fractional Brownian motion. Furthermore, our results suggest that the fractal behaviour of the electromagnetic responses is correlated with degree of the spatial correlation, the contrasts in ground conductivity, and the preferred orientation of small-scale heterogeneity. In addition, the EM responses acquired across a fault zone comprising different lithological units and varying wavelengths of geologic heterogeneity also support our inferences from numerical modelling.

  2. Distribution and frequency of galls induced by Anisodiplosis waltheriae Maia (Diptera: Cecidomyiidae) on the invasive plant Waltheria indica L. (Sterculiaceae).

    Science.gov (United States)

    Almeida, Felipe V M; Santos, Jean C; Silveira, Fernando A O; Fernandes, Geraldo W

    2006-01-01

    The frequency of galls induced by Anisodiplosis waltheriae Maia, a recently described species, on Waltheria indica L. was studied. W indica is an invasive weed in regeneration areas of Atlantic Forest in southeastern Brazil. Plants were collected in May 2004 and above-ground biomass, main stem length, number of leaves, number of galls per leaf and leaf area of each individual were recorded. Nearly 90% of all plants and 25% of all leaves were attacked by the gall midge, with an average of 0.67 galls/leaf. Leaf area had a weak effect on gall abundance while the number of leaves had no effect on gall abundance. Only 31% of the variation in gall abundance was explained by plant biomass. Natural enemies killed one third of the sampled galls. Predation accounted for 22.9% of gall mortality, unknown factors killed 7.6%, microhymenopteran parasitoids killed 2.5% and fungi only 1%. Mortality factors were not influenced by leaf area or gall density.

  3. Frequency distribution of larval codling moth, Cydia pomonella L., aggregations on trees in Unmanaged apple orchards of the Pacific Northwest.

    Science.gov (United States)

    Jumean, Zaid; Wood, Charlene; Gries, Gerhard

    2009-10-01

    The codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), is a key pest of pome fruits in North America. After locating a pupation site, larvae spin a cocoon from which aggregation pheromone disseminates that attracts conspecific larvae. In two unmanaged apple orchards in Wenatchee and Yakima, Washington State, we systematically surveyed cracks and crevices of tree trunks for cocooning C. pomonella larvae. Aggregates of larvae were found significantly more often than solitary larvae. The number of cocooning larvae in aggregates (=group size) was inversely correlated with the frequency occurrence of that group size. Group size ranged between 2 and 20 cocoons. Height above ground had no effect on location of aggregates. In orchard 1, the cardinal direction of the tree trunk had no effect on location of aggregations, but in orchard 2, aggregations were located significantly most often on the south side of trunks. The mean ratio of males and females in aggregations was 1.08:1 and 1.04:1 in orchards 1 and 2, respectively. Moreover, the number of males in aggregates did not significantly differ from that of females. Our data support the conclusion that larvae seek pupation sites not by chance but in large part in response to pheromone signal and microhabitat cues. The probability of aggregates forming is likely proportional to the population density of C. pomonella.

  4. Distribution of feline AB blood types: a review of frequencies and its implications in the Iberian Peninsula.

    Science.gov (United States)

    Vieira, Sandrina M; Ferreira, Rui R F; de Matos, Augusto Jf; Cardoso, Inês M; Graça, Rita M C; Soares, Ana Rpb; Blasi-Brugué, Carles; Sánchez, Ignacio M; Gopegui, Rafael R

    2017-01-01

    The objective of this study was to document the prevalence of feline blood types in the Iberian Peninsula and to determine the potential risk of incompatibility-related transfusion reactions in unmatched transfusions and the potential risk of neonatal isoerythrolysis (NI) in kittens born to parents of unknown blood type. Blood samples were obtained from blood donors of the Animal Blood Bank (BSA-Banco de Sangue Animal). Blood typing was performed using a card method (RapidVet-H Feline Blood Typing; MDS). The studied population comprised 1070 purebred and non-purebred cats from Portugal and Spain aged between 1 and 8 years. Overall, frequencies of blood types A and B were 96.5% and 3.5%, respectively. No AB cats were found. Based on these data, the potential risks of NI and transfusion reactions in unmatched transfusions were calculated to be 6.8% and 2.8%, respectively. Unlike previous studies, no type AB cats were found in this study. Although the calculated potential risks of transfusion reaction in unmatched transfusions and neonatal isoerythrolysis were low, blood typing prior to blood transfusion and blood typing of cats for breeding purposes are highly recommended.

  5. Evaluate the frequency distribution of nonadhesive virulence factors in carbapenemase-producing Acinetobacter baumannii isolated from clinical samples in Kermanshah.

    Science.gov (United States)

    Mohajeri, Parviz; Sharbati, Saba; Farahani, Abbas; Rezaei, Zhaleh

    2016-01-01

    Acinetobacter baumannii which is a Gram-negative bacterium can cause several different infections. The appearance of carbapenemase-producing A. baumannii in recent years has made the treatment process more difficult. The identification of virulence factors (VFs), such as nonadhesives in A. baumannii, helps to fight against related infections. A total of 104 samples from teaching hospitals in Kermanshah, Iran, were collected during a 24 months period (2011-2013). Sample identification was first carried out by biochemical tests, and then their susceptibility to carbapenems was determined using the Kirby-Bauer method. For confirmation of carbapenemase-producing A. baumannii, polymerase chain reaction (PCR) was done for carbapenemase-encoding genes. In addition, the frequency of nonadhesive VFs in carbapenemase-producing isolates was determined by PCR. There were 50 isolates that were identified as carbapenemase-producing A. baumannii. The PCR results showed; 40 isolates (80%) for traT, 17 isolates (34%) for cvaC, and 8 isolates (16%) for iutA, and these encode serum resistance, colicin V and aerobactin, respectively. No significant correlation was observed between these three genes. The mechanism of A. baumannii virulence has always been in question. The role of VFs has also been recognized in other Gram-negative bacteria. According to the prevalence of traT, cvaC and iutA, as nonadhesive VFs, we can suggest that they could be the main mechanism of carbapenemase-producing A. baumannii pathogenesis.

  6. The role of human demographic history in determining the distribution and frequency of transferase-deficient galactosaemia mutations.

    LENUS (Irish Health Repository)

    Flanagan, J M

    2010-02-01

    Classical or transferase-deficient galactosaemia is an inherited metabolic disorder caused by mutation in the human Galactose-1-phosphate uridyl transferase (GALT) gene. Of some 170 causative mutations reported, fewer than 10% are observed in more than one geographic region or ethnic group. To better understand the population history of the common GALT mutations, we have established a haplotyping system for the GALT locus incorporating eight single nucleotide polymorphisms and three short tandem repeat markers. We analysed haplotypes associated with the three most frequent GALT gene mutations, Q188R, K285N and Duarte-2 (D2), and estimated their age. Haplotype diversity, in conjunction with measures of genetic diversity and of linkage disequilibrium, indicated that Q188R and K285N are European mutations. The Q188R mutation arose in central Europe within the last 20 000 years, with its observed east-west cline of increasing relative allele frequency possibly being due to population expansion during the re-colonization of Europe by Homo sapiens in the Mesolithic age. K285N was found to be a younger mutation that originated in Eastern Europe and is probably more geographically restricted as it arose after all major European population expansions. The D2 variant was found to be an ancient mutation that originated before the expansion of Homo sapiens out of Africa.

  7. Frequencies and distributions of sex chromosome abnormalities in females with the Turner phenotype: a long-term retrospective study in the southern region of Turkey

    Science.gov (United States)

    Tanrıverdi, Nilgün; Demirhan, Osman; Süleymanova, Dilara; Pazarbaşı, Ayfer

    2017-11-13

    Background/aim: The genetic background of Turner syndrome (TS) is highly variable. The correlation between genotype and phenotype is not yet well understood. The aim of this study was to describe the frequencies and distributions of Turner karyotypes and to discuss the phenotype/genotype relation in a very large group of individuals with TS. Materials and methods: The karyotype results of 248 female participants were evaluated retrospectively.Results: Of 248 females with the Turner phenotype, 14.5% had normal karyotypes and 85.5% had Turner karyotypes. About 72.2% of the abnormalities were numerical aberrations and 27.8% were structural aberrations. The most frequent karyotype was monosomy X, which was found in 135 females (63.7%), followed by 44 mosaics (21%), 40 isochromosomes of the long and short arms of chromosome X (19.1%), and 17 deletions of the short and long arms of chromosome X (8.0%). One case of Robertsonian translocation and one case of mosaic TS with marker chromosome were detected. Conclusion: This study shows the frequency and distribution of karyotypes in females with TS. There is great value to be gleaned from studies of females with TS in furthering our understanding of the atypical clinical features associated with TS. Studies involving genetic analyses will be necessary to examine gene expression profiles in girls with TS and identify potential candidate genes underlying the atypical clinical features associated with TS.

  8. Study Modules for Calculus-Based General Physics. [Includes Modules 35-37: Reflection and Refraction; Electric Fields and Potentials from Continuous Charge Distributions; and Maxwell's Predictions].

    Science.gov (United States)

    Fuller, Robert G., Ed.; And Others

    This is part of a series of 42 Calculus Based Physics (CBP) modules totaling about 1,000 pages. The modules include study guides, practice tests, and mastery tests for a full-year individualized course in calculus-based physics based on the Personalized System of Instruction (PSI). The units are not intended to be used without outside materials;…

  9. 17 CFR 240.15g-100 - Schedule 15G-Information to be included in the document distributed pursuant to 17 CFR 240.15g-2.

    Science.gov (United States)

    2010-04-01

    ... of investing in penny stocks. Please read it carefully before you agree to purchase or sell a penny... to accurately price. Investors in penny stock should be prepared for the possibility that they may... securities—including penny stocks—is available on the SEC's Web site at http://www.sec.gov/investor/pubs...

  10. Multicritical phase diagrams of the Blume-Emery-Griffiths model with repulsive biquadratic coupling including metastable phases: the pair approximation and the path probability method with pair distribution

    International Nuclear Information System (INIS)

    Keskin, Mustafa; Erdinc, Ahmet

    2004-01-01

    As a continuation of the previously published work, the pair approximation of the cluster variation method is applied to study the temperature dependences of the order parameters of the Blume-Emery-Griffiths model with repulsive biquadratic coupling on a body centered cubic lattice. We obtain metastable and unstable branches of the order parameters besides the stable branches and phase transitions of these branches are investigated extensively. We study the dynamics of the model by the path probability method with pair distribution in order to make sure that we find and define the metastable and unstable branches of the order parameters completely and correctly. We present the metastable phase diagram in addition to the equilibrium phase diagram and also the first-order phase transition line for the unstable branches of the quadrupole order parameter is superimposed on the phase diagrams. It is found that the metastable phase diagram and the first-order phase boundary for the unstable quadrupole order parameter always exist at the low temperatures which are consistent with experimental and theoretical works

  11. Distribution Frequency and Incidence of Seed-borne Pathogens of Some Cereals and Industrial Crops in Serbia

    Directory of Open Access Journals (Sweden)

    Jelena Lević

    2012-01-01

    Full Text Available A total of 41 species of fungi were isolated from seed samples of barley, maize, soybean,and sunflower collected at different locations in Serbia. The majority of detected speciesoccurred on barley (35 of 41 species or 87.8% comparing to soybean (17 of 41 species or41.5%, sunflower (16 of 41 species or 39.0% and maize (15 of 41 species or 36.9%. Speciesbelonging to genera Alternaria, Chaetomium, Epicoccum, Fusarium, Penicillium and Rhizopuswere present on seeds of all four plant species. Alternaria species were dominant on soybean,barley and sunflower seeds (85.7%, 84.7% and 76.9%. F. verticillioides and Penicilliumspp. were mainly isolated from maize seeds (100 and 92.3% respectively, while other specieswere isolated up to 38.5% (Chaetomium spp. and Rhizopus spp.. F. graminearum, F. proliferatum,F. poae and F. sporotrichioides were the most common Fusarium species isolatedfrom barley (51.1-93.3%, while on the soybean seeds F. oxysporum (71.4%, F. semitectum(57.1% and F. sporotrichioides (57.1% were prevalent. Frequency of Fusarium species onsunflower seeds varied from 7% (F. equiseti, F. graminearum, F. proliferatum and F. subglutinansto 15.4% (F. verticillioides. Statistically significant negative correlation (r = –0.678* wasdetermined for the incidence of F. graminearum and Alternaria spp., as well as, Fusarium spp.and Alternaria spp. (r = –0.614*, on barley seeds. The obtained results revealed that seedbornepathogens were present in most seed samples of important cereals and industrialcrops grown under different agroecological conditions in Serbia. Some of the identifiedfungi are potential producers of mycotoxins, thus their presence is important in termsof reduced food safety for humans and animals. Therefore, an early and accurate diagnosisand pathogen surveillance will provide time for the development and the applicationof disease strategies.

  12. Drone Use in Monioring Open Ocean Surface Debris, Including Paired Manta and Tucker Trawls for Relateing Sea State to Vertical Debris Distribution

    Science.gov (United States)

    Lattin, G.

    2016-02-01

    Monitoring debris at sea presents challenges not found in beach or riverine habitats, and is typically done with trawl nets of various apertures and mesh sizes, which limits the size of debris captured and the area surveyed. To partially overcome these limitations in monitoring floating debris, a Quadcopter drone with video transmitting and recording capabilities was deployed at the beginning and the end of manta trawl transects within the North Pacific Subtropical Gyre's eastern convergence zone. Subsurface tucker trawls at 10 meters were conducted at the same time as the manta trawls, in order to assess the effect of sea state on debris dispersal. Trawls were conducted on an 11 station grid used repeatedly since 1999. For drone observations, the operator and observer were stationed on the mother ship while two researchers collected observed debris using a rigid inflatable boat (RIB). The drone was flown to a distance of approximately 100 meters from the vessel in a zigzag or circular search pattern. Here we examine issues arising from drone deployment during the survey: 1) relation of area surveyed by drone to volume of water passing through trawl; 2) retrieval of drone-spotted and associated RIB spotted debris. 3) integrating post- flight image analysis into retrieved debris quantification; and 4) factors limiting drone effectiveness at sea. During the survey, debris too large for the manta trawl was spotted by the drone, and significant debris not observed using the drone was recovered by the RIB. The combination of drone sightings, RIB retrieval, and post flight image analysis leads to improved monitoring of debris at sea. We also examine the issue of the distribution of floating debris during sea states varying from 0-5 by comparing quantities from surface manta trawls to the tucker trawls at a nominal depth of 10 meters.

  13. Frequency and Distribution of Diarrhoeagenic Escherichia Coli Strains Isolated from Pediatric Patients with Diarrhoea in Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    Amela Dedeić-Ljubović

    2009-05-01

    the frequency and most common serotypes of DEC in Bosnia and Herzegovina. Additionally, it is the first report of cases with an O157:K- infection which progressed to HUS, a serious and potentially fatal illness.

  14. Spatial variation in the frequency-magnitude distribution of earthquakes under the tectonic framework in the Middle East

    Science.gov (United States)

    Mousavi, S. Mostafa

    2017-10-01

    Spatial variations of seismic energy released and b-value over the Middle East region are investigated based on a seismicity catalog from 1995 to 2007. The goal is to use these seismic parameters and based on other geodetic and geophysical observations, such as GPS measurements, strain rate model, fault distribution, focal mechanism, crustal model, Q model, and gravity measurements, etc., to uncover spatial patterns that seem anomalous. Areas of high energy released (cumulative) seem to correspond to the areas of relatively high b-values. Areas of high energy released and high b-values seem to correspond very well with the location of continental collision where earthquake activities are high. The divergent boundary between Arabia and African plates and subduction zone at Makran seem to correspond to low to moderate energy release. Northern Pamir, Azerbaijan-Caucasus, the lower part of Zagros Mountains, eastern Turkey, Owen Fracture Zone, Strait of Bob-el-Mandeb, and south of the Sulaiman Shear Zone seem to correspond to high cumulative energy-released, high strain rate, high b-values, and high fault density. While, the central and eastern Iran, southern Zagros, northern Pakistan, Gulf of Aden, Alborz, southwest of the Caspian Sea, western Caucasus and Kopeh-Dagh seem to correspond with lower b-values. The cross-section map for Hindu-Kush shows general decreasing of the b-values with depth, however, a region of high b-value is observed underneath Pamir at depths from 170 to 230 km. This anomaly region can be due to dehydration of Pamir crustal slab at depth.

  15. Effects of tree roots on shallow landslides distribution and frequency in the European Alps using a new physically-based discrete element model

    Science.gov (United States)

    Cohen, Denis; Schwarz, Massimiliano

    2017-04-01

    Shallow landslides are hillslope processes that play a key role in shaping landscapes in forested catchments. Shallow landslides are, in some regions, the dominant regulating mechanisms by which soil is delivered from the hillslopes to steep channels and fluvial systems. Several studies have highlighted the importance of roots to better understand mechanisms of root reinforcement and their contributions to the stabilization of hillslopes. In this context, the spatio-temporal distribution of root reinforcement has a major repercussion on the dynamic of sediment transport at the catchment scale and on the availability of productive soils. Here we present a new model for shallow slope stability calculations, SOSlope, that specifically considers the effects of root reinforcement on shallow landslide initiation. The model is a strain-step discrete element model that reproduces the self-organized redistribution of forces on a slope during rainfall-triggered shallow landslides. Tree roots govern tensile and compressive force redistribution and determine the stability of the slope, the timing, location, and dimension of the failure mass. We use SOSlope to quantify the role of protection forest in several localities in the European Alps, making use of detailed field measurements of root densities and root-size distribution, and root tensile and compressive strength for three species common in the Alps (spruce, fir, and beech) to compute landslide distributions and frequency during landslide-triggering rainfall events. We show the mechanisms by which tree roots impart reinforcement to slopes and offer protection against shallow landslides.

  16. High-throughput sequencing reveals microbial communities in drinking water treatment sludge from six geographically distributed plants, including potentially toxic cyanobacteria and pathogens.

    Science.gov (United States)

    Xu, Hangzhou; Pei, Haiyan; Jin, Yan; Ma, Chunxia; Wang, Yuting; Sun, Jiongming; Li, Hongmin

    2018-04-10

    The microbial community structures of drinking water treatment sludge (DWTS) generated for raw water (RW) from different locations and with different source types - including river water, lake water and reservoir water -were investigated using high-throughput sequencing. Because the unit operations in the six DWTPs were similar, community composition in fresh sludge may be determined by microbial community in the corresponding RW. Although Proteobacteria, Cyanobacteria, Bacteroidetes, Firmicutes, Verrucomicrobia, and Planctomycetes were the dominant phyla among the six DWTS samples, no single phylum exhibited similar abundance across all the samples, owing to differences in total phosphorus, chemical oxygen demand, Al, Fe, and chloride in RW. Three genera of potentially toxic cyanobacteria (Planktothrix, Microcystis and Cylindrospermopsis), and four potential pathogens (Escherichia coli, Bacteroides ovatus, Prevotella copri and Rickettsia) were found in sludge samples. Because proliferation of potentially toxic cyanobacteria and Rickettsia in RW was mainly affected by nutrients, while growth of Escherichia coli, Bacteroides ovatus and Prevotella copri in RW may be influenced by Fe, control of nutrients and Fe in RW is essential to decrease toxic cyanobacteria and pathogens in DWTS. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Personal measures of power-frequency magnetic field exposure among men from an infertility clinic: distribution, temporal variability and correlation with their female partners' exposure

    International Nuclear Information System (INIS)

    Lewis, Ryan C.; Hauser, Russ; Maynard, Andrew D.; Neitzel, Richard L.; Meeker, John D.; Wang, Lu; Kavet, Robert; Morey, Patricia; Ford, Jennifer B.

    2016-01-01

    Power-frequency magnetic field exposure science as it relates to men and couples have not been explored despite the advantage of this information in the design and interpretation of reproductive health epidemiology studies. This analysis examined the distribution and temporal variability of exposures in men, and the correlation of exposures within couples using data from a longitudinal study of 25 men and their female partners recruited from an infertility clinic. The average and 90. percentile demonstrated fair to good reproducibility, whereas the maximum showed poor reproducibility over repeated sampling days, each separated by a median of 4.6 weeks. Average magnetic field exposures were also strongly correlated within couples, suggesting that one partner's data could be used as a surrogate in the absence of data from the other for this metric. Environment was also an important effect modifier in these explored matters. These issues should be considered in future relevant epidemiology studies. (authors)

  18. Frequency and geographic distribution of gyrA and gyrB mutations associated with fluoroquinolone resistance in clinical Mycobacterium tuberculosis isolates: a systematic review.

    Science.gov (United States)

    Avalos, Elisea; Catanzaro, Donald; Catanzaro, Antonino; Ganiats, Theodore; Brodine, Stephanie; Alcaraz, John; Rodwell, Timothy

    2015-01-01

    The detection of mutations in the gyrA and gyrB genes in the Mycobacterium tuberculosis genome that have been demonstrated to confer phenotypic resistance to fluoroquinolones is the most promising technology for rapid diagnosis of fluoroquinolone resistance. In order to characterize the diversity and frequency of gyrA and gyrB mutations and to describe the global distribution of these mutations, we conducted a systematic review, from May 1996 to April 2013, of all published studies evaluating Mycobacterium tuberculosis mutations associated with resistance to fluoroquinolones. The overall goal of the study was to determine the potential utility and reliability of these mutations as diagnostic markers to detect phenotypic fluoroquinolone resistance in Mycobacterium tuberculosis and to describe their geographic distribution. Forty-six studies, covering four continents and 18 countries, provided mutation data for 3,846 unique clinical isolates with phenotypic resistance profiles to fluoroquinolones. The gyrA mutations occurring most frequently in fluoroquinolone-resistant isolates, ranged from 21-32% for D94G and 13-20% for A90V, by drug. Eighty seven percent of all strains that were phenotypically resistant to moxifloxacin and 83% of ofloxacin resistant isolates contained mutations in gyrA. Additionally we found that 83% and 80% of moxifloxacin and ofloxacin resistant strains respectively, were observed to have mutations in the gyrA codons interrogated by the existing MTBDRsl line probe assay. In China and Russia, 83% and 84% of fluoroquinolone resistant strains respectively, were observed to have gyrA mutations in the gene regions covered by the MTBDRsl assay. Molecular diagnostics, specifically the Genotype MTBDRsl assay, focusing on codons 88-94 should have moderate to high sensitivity in most countries. While we did observe geographic differences in the frequencies of single gyrA mutations across countries, molecular diagnostics based on detection of all gyr

  19. Warfarin maintenance dose in older patients: higher average dose and wider dose frequency distribution in patients of African ancestry than those of European ancestry.

    Science.gov (United States)

    Garwood, Candice L; Clemente, Jennifer L; Ibe, George N; Kandula, Vijay A; Curtis, Kristy D; Whittaker, Peter

    2010-06-15

    Studies report that warfarin doses required to maintain therapeutic anticoagulation decrease with age; however, these studies almost exclusively enrolled patients of European ancestry. Consequently, universal application of dosing paradigms based on such evidence may be confounded because ethnicity also influences dose. Therefore, we determined if warfarin dose decreased with age in Americans of African ancestry, if older African and European ancestry patients required different doses, and if their daily dose frequency distributions differed. Our chart review examined 170 patients of African ancestry and 49 patients of European ancestry cared for in our anticoagulation clinic. We calculated the average weekly dose required for each stable, anticoagulated patient to maintain an international normalized ratio of 2.0 to 3.0, determined dose averages for groups 80 years of age and plotted dose as a function of age. The maintenance dose in patients of African ancestry decreased with age (PAfrican ancestry required higher average weekly doses than patients of European ancestry: 33% higher in the 70- to 79-year-old group (38.2+/-1.9 vs. 28.8+/-1.7 mg; P=0.006) and 52% in the >80-year-old group (33.2+/-1.7 vs. 21.8+/-3.8 mg; P=0.011). Therefore, 43% of older patients of African ancestry required daily doses >5mg and hence would have been under-dosed using current starting-dose guidelines. The dose frequency distribution was wider for older patients of African ancestry compared to those of European ancestry (PAfrican ancestry indicate that strategies for initiating warfarin therapy based on studies of patients of European ancestry could result in insufficient anticoagulation and thereby potentially increase their thromboembolism risk. Copyright 2010 Elsevier Inc. All rights reserved.

  20. Frequency distribution of HLA alleles and haplotypes in Uyghur women with advanced squamous cell cervical cancer and relation to HPV status and clinical outcome.

    Science.gov (United States)

    Alifu, Mayinuer; Fan, Peiwen; Kuerban, Gulina; Yao, Xuan; Peng, Yanchun; Dong, Tao; Wang, Ruozheng

    2018-03-01

    This study aims to investigate the association of human leukocyte antigen (HLA) alleles and haplotypes in Uyghur women with advanced squamous cell cervical cancer (SCC). A total of 131 Uyghur patients with advanced SCC (IIb-IVa) and 91 healthy subjects from Xinjiang province were genotyped for HLA-I and II genes using Polymerase Chain Reaction Sequence Based Typing. The different frequencies of HLA alleles and haplotypes between patients and controls were compared and the correlations were analyzed between HLA distribution and HPV status and prognosis. (1) The frequencies of B*51:01, DRB1*07:01, DQB1*02:01, A*01:01-C*06:02, A*01:01-DRB1*07:01, C*06:02-DQB1*02:01, DRB1*07:01-DQB1*02:01 and C*06:02-DRB1*07:01-DQB1*02:01 in cancer group were higher than control group whereas the frequencies of B*44:02, B*58:01, C*05:01, DRB1*04:01, DRB1*12:01, DRB1*13:01, DQB1*02:02, DQB1*05:02, DRB1*03:01-DQB1*02:02 and DRB1*04:01-DQB1*03:02 in cancer group were lower than control group (P HLA alleles and its haplotypes play an important role. B*58:01 allele may act as an independent predictor for DSS.

  1. Contrasting subtropical PV intrusion frequency and their impact on tropospheric Ozone distribution over Pacific Ocean in El-Niño and La-Niña conditions.

    Science.gov (United States)

    Nath, Debashis; Chen, Wen; Graf, Hans-F; Lan, Xiaoqiang; Gong, Hainan

    2017-09-20

    Upper tropospheric equatorial westerly ducts over the Pacific Ocean are the preferred location for Rossby wave breaking events during boreal winter and spring. These subtropical wave breaking events lead to the intrusion of high PV (potential vorticity) air along the extra-tropical tropopause and transport ozone rich dry stratospheric air into the tropics. The intrusion frequency has strong interannual variability due to ENSO (El-Niño/Southern Oscillation), with more events under La-Niña and less under El-Niño conditions. This may result from stronger equatorial westerly ducts and subtropical jets during La-Niña and weaker during El-Niño. It was previously suggested that the interannual variability of the tropospheric ozone distribution over the central-eastern Pacific Ocean is mainly driven by convective activity related to ENSO and that the barotropic nature of the subtropical intrusions restricts the tracers within the UT. However, our analysis shows that tropospheric ozone concentration and subtropical intrusions account ~65% of the co- variability (below 5 km) in the outer tropical (10-25°N) central Pacific Ocean, particularly during La-Niña conditions. Additionally, we find a two-fold increase and westward shift in the intrusion frequency over the Pacific Ocean, due to the climate regime shift in SST pattern during 1997/98.

  2. A Multi-Band Body-Worn Distributed Radio-Frequency Exposure Meter: Design, On-Body Calibration and Study of Body Morphology

    Science.gov (United States)

    Thielens, Arno; Agneessens, Sam; Van Torre, Patrick; Van den Bossche, Matthias; Eeftens, Marloes; Huss, Anke; Vermeulen, Roel; de Seze, René; Mazet, Paul; Cardis, Elisabeth; Röösli, Martin; Martens, Luc; Joseph, Wout

    2018-01-01

    A multi-band Body-Worn Distributed exposure Meter (BWDM) calibrated for simultaneous measurement of the incident power density in 11 telecommunication frequency bands, is proposed. The BDWM consists of 22 textile antennas integrated in a garment and is calibrated on six human subjects in an anechoic chamber to assess its measurement uncertainty in terms of 68% confidence interval of the on-body antenna aperture. It is shown that by using multiple antennas in each frequency band, the uncertainty of the BWDM is 22 dB improved with respect to single nodes on the front and back of the torso and variations are decreased to maximum 8.8 dB. Moreover, deploying single antennas for different body morphologies results in a variation up to 9.3 dB, which is reduced to 3.6 dB using multiple antennas for six subjects with various body mass index values. The designed BWDM, has an improved uncertainty of up to 9.6 dB in comparison to commercially available personal exposure meters calibrated on body. As an application, an average incident power density in the range of 26.7–90.8 μW·m−2 is measured in Ghent, Belgium. The measurements show that commercial personal exposure meters underestimate the actual exposure by a factor of up to 20.6. PMID:29346280

  3. Frequency distribution of specific activities and radiological hazard assessment in surface beach sand samples collected in Bangsaen beach in Chonburi province, Thailand

    Science.gov (United States)

    Changkit, N.; Boonkrongcheep, R.; Youngchauy, U.; Polthum, S.; Kessaratikoon, P.

    2017-09-01

    The specific activities of natural radionuclides (40K, 226Ra and 232Th) in 50 surface beach sand samples collected from Bangsaen beach in Chonburi province in the easthern region of Thailand, were measured and evaluated. Experimental results were obtained by using a high-purity germanium (HPGe) detector and gamma spectrometry analysis system in the special laboratory at Thailand Institute of Nuclear Technology (Public Organization). The IAEA-SOIL-375 reference material was used to analyze the concentration of 40K, 226Ra and 232Th in all samples. It was found that the specific activities of 40K, 226Ra and 232Th were ranged from 510.85 - 771.35, 8.17 - 17.06 and 4.25 - 15.68 Bq/kg. Furthermore, frequency distribution of the specific activities were studied, analyzed and found to be the asymmetrical distribution by using a statistical computer program. Moreover, four radiological hazard indices for the investigated area were also calculated by using the median values of specific activities of 40K, 226Ra and 232Th. The results were also compared with the Office of Atoms for Peace (OAP) annual report data, Thailand and global radioactivity measurement and evaluations.

  4. Distributional Inference

    NARCIS (Netherlands)

    Kroese, A.H.; van der Meulen, E.A.; Poortema, Klaas; Schaafsma, W.

    1995-01-01

    The making of statistical inferences in distributional form is conceptionally complicated because the epistemic 'probabilities' assigned are mixtures of fact and fiction. In this respect they are essentially different from 'physical' or 'frequency-theoretic' probabilities. The distributional form is

  5. Multi-peaked distributions of kHz QPO frequencies in bright neutron star low-mass X-ray binaires

    NARCIS (Netherlands)

    Homan, J.; Belloni, T.; Méndez, R.M.

    2004-01-01

    We have analyzed all published frequencies, v1 and v2, of the twin kiloHertz quasi-periodic oscillations (kHz QPOs) in bright neutron star low-mass X-ray binaries. The two frequencies are well correlated but, contrary to recent suggestions, the frequency-frequency correlation is significantly

  6. Ozone and allergen exposure during postnatal development alters the frequency and airway distribution of CD25+ cells in infant rhesus monkeys

    International Nuclear Information System (INIS)

    Miller, Lisa A.; Gerriets, Joan E.; Tyler, Nancy K.; Abel, Kristina; Schelegle, Edward S.; Plopper, Charles G.; Hyde, Dallas M.

    2009-01-01

    The epidemiologic link between air pollutant exposure and asthma has been supported by experimental findings, but the mechanisms are not understood. In this study, we evaluated the impact of combined ozone and house dust mite (HDM) exposure on the immunophenotype of peripheral blood and airway lymphocytes from rhesus macaque monkeys during the postnatal period of development. Starting at 30 days of age, monkeys were exposed to 11 cycles of filtered air, ozone, HDM aerosol, or ozone + HDM aerosol. Each cycle consisted of ozone delivered at 0.5 ppm for 5 days (8 h/day), followed by 9 days of filtered air; animals received HDM aerosol during the last 3 days of each ozone exposure period. Between 2-3 months of age, animals co-exposed to ozone + HDM exhibited a decline in total circulating leukocyte numbers and increased total circulating lymphocyte frequency. At 3 months of age, blood CD4+/CD25+ lymphocytes were increased with ozone + HDM. At 6 months of age, CD4+/CD25+ and CD8+/CD25+ lymphocyte populations increased in both blood and lavage of ozone + HDM animals. Overall volume of CD25+ cells within airway mucosa increased with HDM exposure. Ozone did not have an additive effect on volume of mucosal CD25+ cells in HDM-exposed animals, but did alter the anatomical distribution of this cell type throughout the proximal and distal airways. We conclude that a window of postnatal development is sensitive to air pollutant and allergen exposure, resulting in immunomodulation of peripheral blood and airway lymphocyte frequency and trafficking

  7. Size-frequency distribution, growth, and mortality of snow crab (Chionoecetes opilio) and arctic lyre crab (Hyas coarctatus) in the chukchi sea from 2009 to 2013

    Science.gov (United States)

    Groß, Jasmin; Konar, Brenda; Brey, Thomas; Grebmeier, Jacqueline M.

    2017-10-01

    The snow crab Chionoecetes opilio and Arctic lyre crab Hyas coarctatus are prominent members of the Chukchi Sea epifaunal community. A better understanding of their life history will aid in determining their role in this ecosystem in light of the changing climate and resource development. In this study, the size frequency distribution, growth, and mortality of these two crab species was examined in 2009, 2010, 2012, and 2013 to determine temporal and spatial patterns within the eastern Chukchi Sea, and to identify potential environmental drivers of the observed patterns. Temporally, the mean size of both sexes of C. opilio and H. coarctatus decreased significantly from 2009 to 2013, with the number of rare maximum sized organisms decreasing significantly to near absence in the latter two study years. Spatially, the mean size of male and female crabs of both species showed a latitudinal trend, decreasing from south to north in the investigation area. Growth of both sexes of C. opilio and H. coarctatus was linear over the sampled size range, and mortality was highest in the latter two study years. Life history features of both species related to different environmental parameters in different years, ranging from temperature, the sediment carbon to nitrogen ratio of the organic content, and sediment grain size distribution. Likely explanations for the observed temporal and spatial variability are ontogenetic migrations of mature crabs to warmer areas possibly due to cooler water temperatures in the latter two study years, or interannual fluctuations, which have been reported for C. opilio populations in other areas where successful waves of recruitment were estimated to occur in eight year intervals. Further research is suggested to determine if the spatial and temporal patterns found in this study are part of the natural variability in this system or if they are an indication of long-term trends.

  8. Geomorphology and Geology of the Southwestern Margaritifer Sinus and Argyre Regions of Mars. Part 2: Crater Size-frequency Distribution Curves and Geomorphic Unit Ages

    Science.gov (United States)

    Parker, T. J.; Pieri, D. C.

    1985-01-01

    In assessing the relative ages of the geomorphic/geologic units, crater counts of the entire unit or nearly the entire unit were made and summed in order to get a more accurate value than obtainable by counts of isolated sections of each unit. Cumulative size-frequency counts show some interesting relationships. Most of the units show two distinct crater populations with a flattening out of the distribution curve at and below 10 km diameter craters. Above this crater size the curves for the different units diverge most notably. In general, the variance may reflect the relative ages of these units. At times, however, in the larger crater size range, these curves can overlap and cross on another. Also the error bars at these larger sizes are broader (and thus more suspect), since counts of larger craters show more scatter, whereas the unit areas remain constant. Occasional clusters of relatively large craters within a given unit, particularly one of limited areal extent, can affect the curve so that the unit might seem to be older than units which it overlies or cuts.

  9. Power-Law Scaling of the Impact Crater Size-Frequency Distribution on Pluto: A Preliminary Analysis Based on First Images from New Horizons' Flyby

    Directory of Open Access Journals (Sweden)

    Scholkmann F.

    2016-01-01

    Full Text Available The recent (14 th July 2015 flyby of NASA’s New Horizons spacecraft of the dwarf planet Pluto resulted in the first high-resolution images of the geological surface- features of Pluto. Since previous studies showed that the impact crater size-frequency distribution (SFD of different celestial objects of our solar system follows power-laws, the aim of the present analysis was to determine, for the first time, the power-law scaling behavior for Pluto’s crater SFD based on the first images available in mid-September 2015. The analysis was based on a high-resolution image covering parts of Pluto’s re- gions Sputnik Planum , Al-Idrisi Montes and Voyager Terra . 83 impact craters could be identified in these regions and their diameter ( D was determined. The analysis re- vealed that the crater diameter SFD shows a statistically significant power-law scaling ( α = 2.4926±0.3309 in the interval of D values ranging from 3.75±1.14 km to the largest determined D value in this data set of 37.77 km. The value obtained for the scaling coefficient α is similar to the coefficient determined for the power-law scaling of the crater SFDs from the other celestial objects in our solar system. Further analysis of Pluto’s crater SFD is warranted as soon as new images are received from the spacecraft.

  10. [Frequency and distribution of sleep problems and insomnia in the adult population in Germany: results of the German Health Interview and Examination Survey for Adults (DEGS1)].

    Science.gov (United States)

    Schlack, R; Hapke, U; Maske, U; Busch, M; Cohrs, S

    2013-05-01

    Sleep disturbances are associated with a variety of physical and mental health disorders and cause high direct and indirect economic costs. The aim of this study was to report the frequency and distribution of problems of sleep onset and maintaining sleep, sleep quality, effective sleep time, and the consumption of sleeping pills in the adult population in Germany. During the 4 weeks prior to the interview, about one third of the respondents reported potentially clinically relevant problems initiating or maintaining sleep; about one-fifth reported poor quality of sleep. When additionally considering impairments during the daytime such as daytime fatigue or exhaustion, a prevalence of 5.7 % for an insomnia syndrome was found. Women were twice as likely to be affected by insomnia-syndrome as men. Significant age differences were not seen. Persons with low socioeconomic status had an increased risk of insomnia (OR: 3.44) as did people residing in West Germany (OR: 1.53). Women with low socioeconomic status (OR: 4.12) and West German men (OR: 1.79) were more affected. The results illustrate the considerable public health relevance of insomnia-related sleep disturbances. An English full-text version of this article is available at SpringerLink as supplemental.

  11. Frequency reference in VSAT

    Science.gov (United States)

    Cheah, Jonathon Y. C.

    1994-02-01

    A low cost technique of frequency reference distribution within a VSAT network is discussed. This technique allows the use of a modestly frequency stable oscillator as the master frequency reference in the hub of a star-connected VSAT network. The need for extremely frequency stable OCXOs in VSATs is completely avoided. This technique was successfully incorporated in the early commercial VSAT networks. It contributes partially to the low cost nature of some of the VSAT networks available today.

  12. Coherent Frequency Reference System for the NASA Deep Space Network

    Science.gov (United States)

    Tucker, Blake C.; Lauf, John E.; Hamell, Robert L.; Gonzaler, Jorge, Jr.; Diener, William A.; Tjoelker, Robert L.

    2010-01-01

    The NASA Deep Space Network (DSN) requires state-of-the-art frequency references that are derived and distributed from very stable atomic frequency standards. A new Frequency Reference System (FRS) and Frequency Reference Distribution System (FRD) have been developed, which together replace the previous Coherent Reference Generator System (CRG). The FRS and FRD each provide new capabilities that significantly improve operability and reliability. The FRS allows for selection and switching between frequency standards, a flywheel capability (to avoid interruptions when switching frequency standards), and a frequency synthesis system (to generate standardized 5-, 10-, and 100-MHz reference signals). The FRS is powered by redundant, specially filtered, and sustainable power systems and includes a monitor and control capability for station operations to interact and control the frequency-standard selection process. The FRD receives the standardized 5-, 10-, and 100-MHz reference signals and distributes signals to distribution amplifiers in a fan out fashion to dozens of DSN users that require the highly stable reference signals. The FRD is also powered by redundant, specially filtered, and sustainable power systems. The new DSN Frequency Distribution System, which consists of the FRS and FRD systems described here, is central to all operational activities of the NASA DSN. The frequency generation and distribution system provides ultra-stable, coherent, and very low phase-noise references at 5, l0, and 100 MHz to between 60 and 100 separate users at each Deep Space Communications Complex.

  13. Boulder abundances and size-frequency distributions on Oxia Planum-Mars: Scientific implications for the 2020 ESA ExoMars rover

    Science.gov (United States)

    Pajola, Maurizio; Rossato, Sandro; Baratti, Emanuele; Pozzobon, Riccardo; Quantin, Cathy; Carter, John; Thollot, Patrick

    2017-11-01

    This paper presents the abundances and the size-frequency distributions (SFD) of boulders identified on a sector of the prime landing site for the ExoMars 2020 rover, in Oxia Planum region. By means of a HiRISE image, boulders ≥ 1.75 m across have been identified and subdivided according to the two main Oxia Planum geological units: the Noachian clay-rich formation (Nc), and the Amazonian volcanic deposit (Av). The spatial density of boulders ≥ 1.75 m over the entire study area is 6.75 × 10-4/m2, with a size-frequency that is best fit both with power-law and exponential-law curves with indices of -4.9 + 0.1/-0.2 and -1.29 + 0.04/-0.06 respectively. Significant differences were found by analysing separately the Av and Nc geological units. The data collected in the Av unit are well-fitted with a power-law curve with an index equal to -4.8 +/-0.2 and with an exponential-law curve with an index of -1.24 + 0.05,-0.06, whilst in the Nc unit such indices are -5.5 + 0.3/-0.4 and -1.70 + 0.09/-0.12 (power-law and exponential-law curve, respectively). The spatial density of boulders in the Av unit is 7.0 times larger than in the Nc one. This may be due primarily to the distinct mechanical properties of the two units that may result in a different production rate or preservation of the boulders. Secondly, the Av unit overlies the Nc unit, possibly resulting in more impacts and/or different weathering processes throughout the ages. This study provides a quantitative evaluation of the abundances of boulders ≥ 1.75 m across on Oxia Planum: it is therefore a reference for the ExoMars 2020 mission, both during the landing phase and the rover traverse to specific areas of interest. The landing ellipse presents much higher abundances of boulders ≥ 1.75 m than all previous Martian rover landing areas. This is particularly evident when the rougher Av unit is taken into account. Contrarily, the Nc unit shows a much more comparable value, but still slightly higher, to the Mars

  14. Radio frequency detection assembly and method for detecting radio frequencies

    Science.gov (United States)

    Cown, Steven H.; Derr, Kurt Warren

    2010-03-16

    A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

  15. Frequencies and ethnic distribution of ABO and RhD blood groups in China: a population-based cross-sectional study.

    Science.gov (United States)

    Liu, Jue; Zhang, Shikun; Wang, Qiaomei; Shen, Haiping; Zhang, Yiping; Liu, Min

    2017-12-03

    ABO and RhD blood groups are key factors affecting blood transfusion safety. The distribution of ABO and RhD blood groups varies globally, but limited data exist for ethnic distributions of these blood groups in Asian populations. We aimed to evaluate the distribution of ABO and RhD blood groups among Chinese ethnic groups. A population-based cross-sectional study. Data on ABO groups and ethnicities were obtained from the National Free Preconception Health Examination Project (NFPHEP) with participants from 220 counties of 31 provinces in China PARTICIPANTS: There were 3 832 034 participants aged 21-49 years who took part in the NFPHEP from January 2010 to December 2012 and were included in this study. The proportion of ABO and RhD blood groups among different ethnic groups was calculated. ABO and RhD blood distribution was significantly different among nine ethnic groups (Pgroups, the Yi group had more A phenotypes (34.0%), and the Manchu (33.7%) and Mongolian (33.3%) ethnic groups had more B phenotypes. The Zhuang group had the greatest proportion of O phenotypes (41.8%), followed by the Miao group (37.7%). AB phenotypes were more frequent in the Uygur ethnic group (10.6%) but lower in the Zhuang group (5.5%). Meanwhile, RhD negativity (RhD-) was greater in the Uygur group (3.3%) than in the Mongolian (0.3%) and Manchu ethnic groups (0.4%). O RhD- blood groups were more frequent in the Uygur group (0.8%) than in the other ethnic groups (0.1%-0.4%, Pblood phenotypes vary across different ethnic groups in China. The diversity in the distribution of the ABO and RhD blood groups in different ethnic groups should be considered when developing rational and evidence-based strategies for blood collection and management. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  16. Parsimonious nonstationary flood frequency analysis

    Science.gov (United States)

    Serago, Jake M.; Vogel, Richard M.

    2018-02-01

    There is now widespread awareness of the impact of anthropogenic influences on extreme floods (and droughts) and thus an increasing need for methods to account for such influences when estimating a frequency distribution. We introduce a parsimonious approach to nonstationary flood frequency analysis (NFFA) based on a bivariate regression equation which describes the relationship between annual maximum floods, x, and an exogenous variable which may explain the nonstationary behavior of x. The conditional mean, variance and skewness of both x and y = ln (x) are derived, and combined with numerous common probability distributions including the lognormal, generalized extreme value and log Pearson type III models, resulting in a very simple and general approach to NFFA. Our approach offers several advantages over existing approaches including: parsimony, ease of use, graphical display, prediction intervals, and opportunities for uncertainty analysis. We introduce nonstationary probability plots and document how such plots can be used to assess the improved goodness of fit associated with a NFFA.

  17. Time-dependent density functional theory (TD-DFT) coupled with reference interaction site model self-consistent field explicitly including spatial electron density distribution (RISM-SCF-SEDD)

    Science.gov (United States)

    Yokogawa, D.

    2016-09-01

    Theoretical approach to design bright bio-imaging molecules is one of the most progressing ones. However, because of the system size and computational accuracy, the number of theoretical studies is limited to our knowledge. To overcome the difficulties, we developed a new method based on reference interaction site model self-consistent field explicitly including spatial electron density distribution and time-dependent density functional theory. We applied it to the calculation of indole and 5-cyanoindole at ground and excited states in gas and solution phases. The changes in the optimized geometries were clearly explained with resonance structures and the Stokes shift was correctly reproduced.

  18. Grid Frequency Extreme Event Analysis and Modeling: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Florita, Anthony R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Clark, Kara [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gevorgian, Vahan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Folgueras, Maria [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wenger, Erin [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-01

    Sudden losses of generation or load can lead to instantaneous changes in electric grid frequency and voltage. Extreme frequency events pose a major threat to grid stability. As renewable energy sources supply power to grids in increasing proportions, it becomes increasingly important to examine when and why extreme events occur to prevent destabilization of the grid. To better understand frequency events, including extrema, historic data were analyzed to fit probability distribution functions to various frequency metrics. Results showed that a standard Cauchy distribution fit the difference between the frequency nadir and prefault frequency (f_(C-A)) metric well, a standard Cauchy distribution fit the settling frequency (f_B) metric well, and a standard normal distribution fit the difference between the settling frequency and frequency nadir (f_(B-C)) metric very well. Results were inconclusive for the frequency nadir (f_C) metric, meaning it likely has a more complex distribution than those tested. This probabilistic modeling should facilitate more realistic modeling of grid faults.

  19. Individual Differences in the Joint Effects of Semantic Priming and Word Frequency Revealed by RT Distributional Analyses: The Role of Lexical Integrity

    Science.gov (United States)

    Yap, Melvin J.; Tse, Chi-Shing; Balota, David A.

    2009-01-01

    Word frequency and semantic priming effects are among the most robust effects in visual word recognition, and it has been generally assumed that these two variables produce interactive effects in lexical decision performance, with larger priming effects for low-frequency targets. The results from four lexical decision experiments indicate that the…

  20. Conversion frequence

    International Nuclear Information System (INIS)

    Sauteret, C.

    1987-03-01

    The experimental evidence of short wavelength for laser inertial confinement has strongly increased the interest in high efficiency harmonic conversion of powerful Nd: glass lasers. This work describes our high power harmonic conversion experiments performed using the same laser apparatus for doubling, tripling the three high power 1064 nm P102, OCTAL and PHEBUS lasers. In addition to the understanding the physics of harmonic conversion, this work includes the basic concepts allows us to improve the technique such as non colinear schemes, to extend this method to other frequencies (fourth generation) and to predict some physical limits [fr

  1. Low-Frequency Observations of Galactic Supernova Remnants and the Distribution of Low-Density Ionized Gas in the Interstellar Medium

    National Research Council Canada - National Science Library

    Kassim, Namir E

    1989-01-01

    .... These observations are combined with other low-frequency data to derive free-free optical depths toward 47 SNRs and to constrain the physical properties of the ionized gas responsible for the absorption...

  2. Efficient methods for including quantum effects in Monte Carlo calculations of large systems: extension of the displaced points path integral method and other effective potential methods to calculate properties and distributions.

    Science.gov (United States)

    Mielke, Steven L; Dinpajooh, Mohammadhasan; Siepmann, J Ilja; Truhlar, Donald G

    2013-01-07

    We present a procedure to calculate ensemble averages, thermodynamic derivatives, and coordinate distributions by effective classical potential methods. In particular, we consider the displaced-points path integral (DPPI) method, which yields exact quantal partition functions and ensemble averages for a harmonic potential and approximate quantal ones for general potentials, and we discuss the implementation of the new procedure in two Monte Carlo simulation codes, one that uses uncorrelated samples to calculate absolute free energies, and another that employs Metropolis sampling to calculate relative free energies. The results of the new DPPI method are compared to those from accurate path integral calculations as well as to results of two other effective classical potential schemes for the case of an isolated water molecule. In addition to the partition function, we consider the heat capacity and expectation values of the energy, the potential energy, the bond angle, and the OH distance. We also consider coordinate distributions. The DPPI scheme performs best among the three effective potential schemes considered and achieves very good accuracy for all of the properties considered. A key advantage of the effective potential schemes is that they display much lower statistical sampling variances than those for accurate path integral calculations. The method presented here shows great promise for including quantum effects in calculations on large systems.

  3. Commutated inversor at low frequency for application of fuel cells in distributed generation; Inversor comutado em baixa frequencia para aplicacao de CaCs na geracao distribuida

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Geomar Machado; Pomilio, Jose Antenor; Vendrusculo, Edson A. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Eletrica e de Computacao], e-mail: antenor@dsce.fee.unicamp.br

    2004-07-01

    The connection of Fuel Cell Power Plants with the utility grid generally needs an electronic power converter for processing the locally generated power and injecting current into the system. Since the source provides a DC voltage, the converter must be able to produce a low-distortion, high-power factor AC current. This paper presents the results obtained with use of a three-phase and a single-phase inverter using low-frequency commutation. An auxiliary circuit is added to the inverter topologies in order to reduce the output voltage distortion, thus improving the current waveform. The main advantages of this approach are the minimization of the switching losses (i.e. high efficiency) and the elimination of the EMI (which avoids high-frequency filters necessary in high-frequency commutation inverters). (author)

  4. Molecular spectrum of KRAS, NRAS, BRAF, PIK3CA, TP53, and APC somatic gene mutations in Arab patients with colorectal cancer: determination of frequency and distribution pattern

    Science.gov (United States)

    Al-Shamsi, Humaid O.; Jones, Jeremy; Fahmawi, Yazan; Dahbour, Ibrahim; Tabash, Aziz; Abdel-Wahab, Reham; Abousamra, Ahmed O. S.; Shaw, Kenna R.; Xiao, Lianchun; Hassan, Manal M.; Kipp, Benjamin R.; Kopetz, Scott; Soliman, Amr S.; McWilliams, Robert R.; Wolff, Robert A.

    2016-01-01

    Background The frequency rates of mutations such as KRAS, NRAS, BRAF, and PIK3CA in colorectal cancer (CRC) differ among populations. The aim of this study was to assess mutation frequencies in the Arab population and determine their correlations with certain clinicopathological features. Methods Arab patients from the Arab Gulf region and a population of age- and sex-matched Western patients with CRC whose tumors were evaluated with next-generation sequencing (NGS) were identified and retrospectively reviewed. The mutation rates of KRAS, NRAS, BRAF, PIK3CA, TP53, and APC were recorded, along with clinicopathological features. Other somatic mutation and their rates were also identified. Fisher’s exact test was used to determine the association between mutation status and clinical features. Results A total of 198 cases were identified; 99 Arab patients and 99 Western patients. Fifty-two point seven percent of Arab patients had stage IV disease at initial presentation, 74.2% had left-sided tumors. Eighty-nine point two percent had tubular adenocarcinoma and 10.8% had mucinous adenocarcinoma. The prevalence rates of KRAS, NRAS, BRAF, PIK3CA, TP53, APC, SMAD, FBXW7 mutations in Arab population were 44.4%, 4%, 4%, 13.1%, 52.5%, 27.3%, 2% and 3% respectively. Compared to 48.4%, 4%, 4%, 12.1%, 47.5%, 24.2%, 11.1% and 0% respectively in matched Western population. Associations between these mutations and patient clinicopathological features were not statistically significant. Conclusions This is the first study to report comprehensive hotspot mutations using NGS in Arab patients with CRC. The frequency of KRAS, NRAS, BRAF, TP53, APC and PIK3CA mutations were similar to reported frequencies in Western population except SMAD4 that had a lower frequency and higher frequency of FBXW7 mutation. PMID:28078112

  5. Observation of Frequency Locked Coherent Transition Radiation

    CERN Document Server

    Marsh, Roark A; Temkin, Richard J

    2005-01-01

    Measurements of frequency locked, coherent transition radiation (CTR) were performed at the 17 GHz high-gradient accelerator facility built by Haimson Research Corporation at MIT PSFC. CTR produced from a metallic foil placed in the beam path was extracted through a window, and measured with a variety of detectors, including: diode, Helium cooled Si Bolometer, and double heterodyne receiver system. The angular energy distribution measured by the diode and bolometer are in agreement and consistent with calculations for a 15 MeV 200 mA 110 ns beam of 1 ps bunches. Heterodyne receiver measurements were able to show frequency locking, namely inter-bunch coherence at integer multiples of the accelerator RF frequency of 17.14 GHz. At the locked frequencies the power levels are enhanced by the number of bunches in a single beam pulse. The CTR was measured as a comb of locked frequencies up to 240 GHz, with a bandwidth of 50 MHz.

  6. Models of Emission-Line Profiles and Spectral Energy Distributions to Characterize the Multi-Frequency Properties of Active Galactic Nuclei

    Directory of Open Access Journals (Sweden)

    Giovanni La Mura

    2017-11-01

    Full Text Available The spectra of active galactic nuclei (AGNs are often characterized by a wealth of emission lines with different profiles and intensity ratios that lead to a complicated classification. Their electromagnetic radiation spans more than 10 orders of magnitude in frequency. In spite of the differences between various classes, the origin of their activity is attributed to a combination of emitting components, surrounding an accreting supermassive black hole (SMBH, in the unified model. Currently, the execution of sky surveys, with instruments operating at various frequencies, provides the possibility to detect and to investigate the properties of AGNs on very large statistical samples. As a result of the spectroscopic surveys that allow the investigation of many objects, we have the opportunity to place new constraints on the nature and evolution of AGNs. In this contribution, we present the results obtained by working on multi-frequency data, and we discuss their relations with the available optical spectra. We compare our findings with the AGN unified model predictions, and we present a revised technique to select AGNs of different types from other line-emitting objects. We discuss the multi-frequency properties in terms of the innermost structures of the sources.

  7. On the frequency distributions per unit area of the projected and etchable lengths of surface-intersecting fission tracks: influences of track revelation, observation and measurement

    CERN Document Server

    Jonckheere, R

    1999-01-01

    In addition to the statistical bounds discussed, thermal history analysis based on the projected and etchable length distributions of surface intersecting fission tracks is limited by systematic factors related to track revelation, observation and measurement. The effects of track revelation, in particular, distort these distributions in the length intervals of interest. An observation threshold poses a problem if it is described by a critical angle theta sub c , but not if it is described by other criteria proposed in the literature. Measurement imprecisions, predictably, blur the thermal history information contained in these distributions. Measurements of semi-confined tracks, added as a result of surface etching, are a more promising alternative to confined track length measurements for accessing the thermal history record in the fission track length distribution. On the other hand, measurements of the projected lengths of surface intersecting tracks offer the theoretical possibility of determining the tr...

  8. [Population density, age distribution and urbanisation as factors influencing the frequency of home visits--an analysis for Mecklenburg-West Pomerania].

    Science.gov (United States)

    Heymann, R; Weitmann, K; Weiss, S; Thierfelder, D; Flessa, S; Hoffmann, W

    2009-07-01

    This study examines and compares the frequency of home visits by general practitioners in regions with a lower population density and regions with a higher population density. The discussion centres on the hypothesis whether the number of home visits in rural and remote areas with a low population density is, in fact, higher than in urbanised areas with a higher population density. The average age of the population has been considered in both cases. The communities of Mecklenburg West-Pomerania were aggregated into postal code regions. The analysis is based on these postal code regions. The average frequency of home visits per 100 inhabitants/km2 has been calculated via a bivariate, linear regression model with the population density and the average age for the postal code region as independent variables. The results are based on billing data of the year 2006 as provided by the Association of Statutory Health Insurance Physicians of Mecklenburg-Western Pomerania. In a second step a variable which clustered the postal codes of urbanised areas was added to a multivariate model. The hypothesis of a negative correlation between the frequency of home visits and the population density of the areas examined cannot be confirmed for Mecklenburg-Western Pomerania. Following the dichotomisation of the postal code regions into sparsely and densely populated areas, only the very sparsely populated postal code regions (less than 100 inhabitants/km2) show a tendency towards a higher frequency of home visits. Overall, the frequency of home visits in sparsely populated postal code regions is 28.9% higher than in the densely populated postal code regions (more than 100 inhabitants/km2), although the number of general practitioners is approximately the same in both groups. In part this association seems to be confirmed by a positive correlation between the average age in the individual postal code regions and the number of home visits carried out in the area. As calculated on the

  9. Intelligent distributed control for nuclear power plants. Final (third annual) technical progress report, September 1991--June 1993 (September 1989--June 1993): Includes no-cost extension period from September 1992--June 1993

    Energy Technology Data Exchange (ETDEWEB)

    Klevans, E.H.

    1993-12-31

    This project was initiated in September 1989 as a three year project to develop and demonstrate Intelligent Distributed Control (IDC) for Nuclear Power Plants. There were two primary goals of this research project. The first goal was to combine diagnostics and control to achieve a highly automated power plant as described by M.A. Schultz. The second goal was to apply this research to develop a prototype demonstration on an actual power plant system, the EBR-2 steam plant. Described in this Final (Third Annual) Technical Progress Report is the accomplishment of the project`s final milestone, an in-plant intelligent control experiment conducted on April 1, 1993. The development of the experiment included: simulation validation, experiment formulation and final programming, procedure development and approval, and experimental results. Other third year developments summarized in this report are: (1) a theoretical foundation for Reconfigurable Hybrid Supervisory Control, (2) a steam plant diagnostic system, (3) control console design tools and (4) other advanced and intelligent control.

  10. Analysis of Maneuvering Targets with Complex Motions by Two-Dimensional Product Modified Lv?s Distribution for Quadratic Frequency Modulation Signals

    OpenAIRE

    Jing, Fulong; Jiao, Shuhong; Hou, Changbo; Si, Weijian; Wang, Yu

    2017-01-01

    For targets with complex motion, such as ships fluctuating with oceanic waves and high maneuvering airplanes, azimuth echo signals can be modeled as multicomponent quadratic frequency modulation (QFM) signals after migration compensation and phase adjustment. For the QFM signal model, the chirp rate (CR) and the quadratic chirp rate (QCR) are two important physical quantities, which need to be estimated. For multicomponent QFM signals, the cross terms create a challenge for detection, which n...

  11. Transmission system for distribution of video over long-haul optical point-to-point links using a microwave photonic filter in the frequency range of 0.01-10 GHz

    Science.gov (United States)

    Zaldívar Huerta, Ignacio E.; Pérez Montaña, Diego F.; Nava, Pablo Hernández; Juárez, Alejandro García; Asomoza, Jorge Rodríguez; Leal Cruz, Ana L.

    2013-12-01

    We experimentally demonstrate the use of an electro-optical transmission system for distribution of video over long-haul optical point-to-point links using a microwave photonic filter in the frequency range of 0.01-10 GHz. The frequency response of the microwave photonic filter consists of four band-pass windows centered at frequencies that can be tailored to the function of the spectral free range of the optical source, the chromatic dispersion parameter of the optical fiber used, as well as the length of the optical link. In particular, filtering effect is obtained by the interaction of an externally modulated multimode laser diode emitting at 1.5 μm associated to the length of a dispersive optical fiber. Filtered microwave signals are used as electrical carriers to transmit TV-signal over long-haul optical links point-to-point. Transmission of TV-signal coded on the microwave band-pass windows located at 4.62, 6.86, 4.0 and 6.0 GHz are achieved over optical links of 25.25 km and 28.25 km, respectively. Practical applications for this approach lie in the field of the FTTH access network for distribution of services as video, voice, and data.

  12. Demand as frequency controlled reserve

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z.; Togeby, M.; OEstergaard, J.

    2008-09-15

    Using demand as frequency controlled reserve (DFR) is an emerging technology which allow demand to participate actively in maintaining the system operation without reducing the energy service delivered to the customer and without need of user interaction. The basic premise is that traditional frequency controlled reserves from power plants and interconnections with neighbouring systems can be costly, slow and not fulfil the need for future power grids with a high share of wind power and fewer central power plants, and an intention to perform flexible operation such as is landing. Electricity demands, on the other hand, have advantages as frequency reserve including fast activation speed, smooth linear activation, low expected costs, and well-dispersed in the distribution grid. The main challenge of DFR is new methods for monitoring the available capacity. This project has investigated the technology of using electricity demands for providing frequency reserve to power systems. Within the project the potential and economy of DFR compatible loads in Denmark has been investigated, control logic has been designed, power system impact has been investigated, potential business models has been evaluated and an implementation strategy has been suggested. The tasks and goals of the project have been successfully accomplished based on which the conclusion and future recommendation are made. This project has developed the DFR technology that enables electricity demands to autonomously disconnect or reconnect to the grid in response to system frequency variations. The developed DFR technology is proved to be a promising technology from several perspectives. Technically, using DFR is feasible to provide reserves and enhance power system frequency control, while fulfilling technical requirements such as linear activation (or reconnection) according to frequency (or time). Environmentally, the DFR technology is pollution free in contrast to traditional reserves from generation

  13. Frequency standards

    CERN Document Server

    Riehle, Fritz

    2006-01-01

    Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

  14. Frequencies distribution of dihydrofolate reductase and dihydropteroate synthetase mutant alleles associated with sulfadoxine-pyrimethamine resistance in Plasmodium falciparum population from Hadhramout Governorate, Yemen.

    Science.gov (United States)

    Bamaga, Omar A A; Mahdy, Mohammed A K; Lim, Yvonne A L

    2015-12-22

    Malaria in Yemen is mainly caused by Plasmodium falciparum and 25% of the population is at high risk. Sulfadoxine-pyrimethamine (SP) had been used as monotherapy against P. falciparum. Emergence of chloroquine resistance led to the shift in anti-malarial treatment policy in Yemen to artemisinin-based combination therapy, that is artesunate (AS) plus SP as first-line therapy for uncomplicated malaria and artemether-lumefantrine as second-line treatment. This study aimed to screen mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes associated with SP resistance among P. falciparum population in Hadhramout governorate, Yemen. Genomic DNA was extracted from dried blood spots of 137 P. falciparum isolates collected from a community-based study. DNA was amplified using nested polymerase chain reaction (PCR) and subsequently sequenced for Pfdhfr and Pfdhps genes. Sequences were analysed for mutations in Pfdhfr gene codons 51, 59, 108, and 164 and in Pfdhps gene codons 436, 437, and 540. A total of 128 and 114 P. falciparum isolates were successfully sequenced for Pfdhfr and Pfdhps genes, respectively. Each Pfdhfr mutant allele (I51 and N108) in P. falciparum population had a frequency of 84%. Pfdhfr R59 mutant allele was detected in one isolate. Mutation at codon 437 (G437) in the Pfdhps gene was detected in 44.7% of falciparum malaria isolates. Frequencies of Pfdhfr double mutant genotype (I51C59N108I164) and Pfdhfr/Pfdhps triple mutant genotype (I51C59N108I164-S436G437K540) were 82.8 and 39.3%, respectively. One isolate harboured Pfdhfr triple mutant genotype (I51, R59, N108, I164) and Pfdhfr/Pfdhps quadruple mutant genotype (I51R59N108I164-S436G437K540). High frequencies of Pfdhfr and Pfdhps mutant alleles and genotypes in P. falciparum population in Hadhramout, Yemen, highlight the risk of developing resistance for SP, the partner drug of AS, which subsequently will expose the parasite to AS monotherapy increasing then the

  15. Impact of microbial distributions on food safety

    NARCIS (Netherlands)

    Bassett, J.; Jackson, T.; Jewell, K.; Jongenburger, I.; Zwietering, M.H.

    2010-01-01

    This document discusses mechanisms impacting on physical distributions of microorganisms in foods, characteristics and suitability of frequency distributions employed to model microbial distributions, and the impact of both physical and frequency distributions on illness risk and food safety

  16. Robust power system frequency control

    CERN Document Server

    Bevrani, Hassan

    2014-01-01

    This updated edition of the industry standard reference on power system frequency control provides practical, systematic and flexible algorithms for regulating load frequency, offering new solutions to the technical challenges introduced by the escalating role of distributed generation and renewable energy sources in smart electric grids. The author emphasizes the physical constraints and practical engineering issues related to frequency in a deregulated environment, while fostering a conceptual understanding of frequency regulation and robust control techniques. The resulting control strategi

  17. Impact factor distribution revisited

    Science.gov (United States)

    Huang, Ding-wei

    2017-09-01

    We explore the consistency of a new type of frequency distribution, where the corresponding rank distribution is Lavalette distribution. Empirical data of journal impact factors can be well described. This distribution is distinct from Poisson distribution and negative binomial distribution, which were suggested by previous study. By a log transformation, we obtain a bell-shaped distribution, which is then compared to Gaussian and catenary curves. Possible mechanisms behind the shape of impact factor distribution are suggested.

  18. Frequency Synthesiser

    NARCIS (Netherlands)

    Drago, Salvatore; Sebastiano, Fabio; Leenaerts, Dominicus M.W.; Breems, Lucien J.; Nauta, Bram

    2016-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  19. Frequency synthesiser

    NARCIS (Netherlands)

    Drago, S.; Sebastiano, Fabio; Leenaerts, Dominicus Martinus Wilhelmus; Breems, Lucien Johannes; Nauta, Bram

    2010-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  20. Electrothermal frequency reference

    NARCIS (Netherlands)

    Makinwa, K.A.A.; Kashmiri, S.M.

    2011-01-01

    An electrothermal frequency-locked loop (EFLL) circuit is described. This EFLL circuit includes an oscillator in a feedback loop. A drive circuit in the EFLL circuit generates a first signal having a fundamental frequency, and an electrothermal filter (ETF) in the EFLL circuit provides a second

  1. Signal frequency distribution and natural-time analyses from acoustic emission monitoring of an arched structure in the Castle of Racconigi

    Directory of Open Access Journals (Sweden)

    G. Niccolini

    2017-07-01

    Full Text Available The stability of an arch as a structural element in the thermal bath of King Charles Albert (Carlo Alberto in the Royal Castle of Racconigi (on the UNESCO World Heritage List since 1997 was assessed by the acoustic emission (AE monitoring technique with application of classical inversion methods to recorded AE data. First, damage source location by means of triangulation techniques and signal frequency analysis were carried out. Then, the recently introduced method of natural-time analysis was preliminarily applied to the AE time series in order to reveal a possible entrance point to a critical state of the monitored structural element. Finally, possible influence of the local seismic and microseismic activity on the stability of the monitored structure was investigated. The criterion for selecting relevant earthquakes was based on the estimation of the size of earthquake preparation zones. The presented results suggest the use of the AE technique as a tool for detecting both ongoing structural damage processes and microseismic activity during preparation stages of seismic events.

  2. Signal frequency distribution and natural-time analyses from acoustic emission monitoring of an arched structure in the Castle of Racconigi

    Science.gov (United States)

    Niccolini, Gianni; Manuello, Amedeo; Marchis, Elena; Carpinteri, Alberto

    2017-07-01

    The stability of an arch as a structural element in the thermal bath of King Charles Albert (Carlo Alberto) in the Royal Castle of Racconigi (on the UNESCO World Heritage List since 1997) was assessed by the acoustic emission (AE) monitoring technique with application of classical inversion methods to recorded AE data. First, damage source location by means of triangulation techniques and signal frequency analysis were carried out. Then, the recently introduced method of natural-time analysis was preliminarily applied to the AE time series in order to reveal a possible entrance point to a critical state of the monitored structural element. Finally, possible influence of the local seismic and microseismic activity on the stability of the monitored structure was investigated. The criterion for selecting relevant earthquakes was based on the estimation of the size of earthquake preparation zones. The presented results suggest the use of the AE technique as a tool for detecting both ongoing structural damage processes and microseismic activity during preparation stages of seismic events.

  3. Metamaterial for Radar Frequencies

    Science.gov (United States)

    2012-09-01

    capacitive coupling with adjacent patches, as shown in Figure 3. The via provides inductance to ground. Figure 3. (a) Planar LH distributed periodic...After [20]). The capacitance in the structure balances out the inductance present when the cylinder is placed in a square array. The metallic... RADAR FREQUENCIES by Szu Hau Tan September 2012 Thesis Advisor: David C. Jenn Second Reader: James Calusdian

  4. Waveform frequency notching

    Science.gov (United States)

    Doerry, Armin W.; Andrews, John

    2017-05-09

    The various technologies presented herein relate to incorporating one or more notches into a radar spectrum, whereby the notches relate to one or more frequencies for which no radar transmission is to occur. An instantaneous frequency is monitored and if the frequency is determined to be of a restricted frequency, then a radar signal can be modified. Modification can include replacing the signal with a signal having a different instantaneous amplitude, a different instantaneous phase, etc. The modification can occur in a WFS prior to a DAC, as well as prior to a sin ROM component and/or a cos ROM component. Further, the notch can be dithered to enable formation of a deep notch. The notch can also undergo signal transitioning to enable formation of a deep notch. The restricted frequencies can be stored in a LUT against which an instantaneous frequency can be compared.

  5. Distribution and Frequency of kdr Mutations within Anopheles gambiae s.l. Populations and First Report of the Ace.1G119S Mutation in Anopheles arabiensis from Burkina Faso (West Africa)

    Science.gov (United States)

    Dabiré, Roch K.; Namountougou, Moussa; Diabaté, Abdoulaye; Soma, Dieudonné D.; Bado, Joseph; Toé, Hyacinthe K.; Bass, Chris; Combary, Patrice

    2014-01-01

    An entomological survey was carried out at 15 sites dispersed throughout the three eco-climatic regions of Burkina Faso (West Africa) in order to assess the current distribution and frequency of mutations that confer resistance to insecticides in An. gambiae s.l. populations in the country. Both knockdown (kdr) resistance mutation variants (L1014F and L1014S), that confer resistance to pyrethroid insecticides, were identified concomitant with the ace-1 G119S mutation confirming the presence of multiple resistance mechanisms in the An. gambiae complex in Burkina Faso. Compared to the last survey, the frequency of the L1014F kdr mutation appears to have remained largely stable and relatively high in all species. In contrast, the distribution and frequency of the L1014S mutation has increased significantly in An. gambiae s.l. across much of the country. Furthermore we report, for the first time, the identification of the ace.1 G116S mutation in An. arabiensis populations collected at 8 sites. This mutation, which confers resistance to organophosphate and carbamate insecticides, has been reported previously only in the An. gambiae S and M molecular forms. This finding is significant as organophosphates and carbamates are used in indoor residual sprays (IRS) to control malaria vectors as complementary strategies to the use of pyrethroid impregnated bednets. The occurrence of the three target-site resistance mutations in both An. gambiae molecular forms and now An. arabiensis has significant implications for the control of malaria vector populations in Burkina Faso and for resistance management strategies based on the rotation of insecticides with different modes of action. PMID:25077792

  6. Water Distribution Lines, Includes water pipes (not connections to structures, fire hydrants and other features. Capture in Microstation and does not contain attribution. Has annotation and is converted to GIS semi-anually. Only available upon permission., Published in 2011, 1:2400 (1in=200ft) scale, Howard County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Water Distribution Lines dataset current as of 2011. Includes water pipes (not connections to structures, fire hydrants and other features. Capture in Microstation...

  7. Anti-interleukin-1 alpha autoantibodies in humans: Characterization, isotype distribution, and receptor-binding inhibition--higher frequency in Schnitzler's syndrome (urticaria and macroglobulinemia)

    Energy Technology Data Exchange (ETDEWEB)

    Saurat, J.H.; Schifferli, J.; Steiger, G.; Dayer, J.M.; Didierjean, L. (Department of Dermatology, University Hospital, Geneva (Switzerland))

    1991-08-01

    Since autoantibodies (Abs) to cytokines may modify their biologic activities, high-affinity binding factors for interleukin-1 alpha (IL-1 alpha BF) were characterized in human sera. IL-1 alpha BF was identified as IgG (1) by sucrose density-gradient centrifugation followed by immunodiffusion autoradiography, (2) by ligand-blotting method, (3) by ligand binding to affinity-immobilized serum IgG, and (4) by IgG affinity purification followed by sucrose density-gradient centrifugation. IL-1 alpha binding activity resided in the F(ab)2 fragment. The apparent equilibrium constant was in the range of IgG found after immunization with conventional antigens (i.e., 10(-9) to 10(-10) mol/L). Anti-IL-1 alpha IgG auto-Abs represented only an extremely small fraction of total IgG (less than 1/10(-5)). Some sera with IL-1 alpha BF and purified IgG thereof were able to inhibit by 96% to 98% the binding of human recombinant IL-1 alpha to its receptor on murine thymoma EL4-6.1 cells, whereas other sera did not. When 125I-labeled anti-IL-1 alpha IgG complexes were injected into rats, they prolonged the plasma half-life of 125I-labeled IL-1 alpha several fold and altered its tissue distribution. The predominant class was IgG (12/19), mainly IgG4 (9/19), but in five of the sera, anti-IL-1 alpha IgA was also detected. In a screening of 271 sera, IL-1 alpha BF was detected in 17/98 normal subjects and was not more frequent in several control groups of patients, except in patients with Schnitzler's syndrome (fever, chronic urticaria, bone pain, and monoclonal IgM paraprotein) (6/9; p less than 0.005). The pathologic significance of these auto-Abs remains to be determined.

  8. Pump apparatus including deconsolidator

    Energy Technology Data Exchange (ETDEWEB)

    Sonwane, Chandrashekhar; Saunders, Timothy; Fitzsimmons, Mark Andrew

    2014-10-07

    A pump apparatus includes a particulate pump that defines a passage that extends from an inlet to an outlet. A duct is in flow communication with the outlet. The duct includes a deconsolidator configured to fragment particle agglomerates received from the passage.

  9. Optical modulator including grapene

    Science.gov (United States)

    Liu, Ming; Yin, Xiaobo; Zhang, Xiang

    2016-06-07

    The present invention provides for a one or more layer graphene optical modulator. In a first exemplary embodiment the optical modulator includes an optical waveguide, a nanoscale oxide spacer adjacent to a working region of the waveguide, and a monolayer graphene sheet adjacent to the spacer. In a second exemplary embodiment, the optical modulator includes at least one pair of active media, where the pair includes an oxide spacer, a first monolayer graphene sheet adjacent to a first side of the spacer, and a second monolayer graphene sheet adjacent to a second side of the spacer, and at least one optical waveguide adjacent to the pair.

  10. Frequency and anatomical distribution of magnetic resonance imaging features in sacroiliac joints of young athletes: Exploring "background noise" towards a data-driven definition of sacroiliitis in early spondyloarthritis.

    Science.gov (United States)

    Weber, Ulrich; Jurik, Anne Grethe; Zejden, Anna; Larsen, Ejnar; Jørgensen, Steen Hylgaard; Rufibach, Kaspar; Schioldan, Christian; Schmidt-Olsen, Søren

    2018-02-12

    Low grade bone marrow edema (BME) was reported in the sacroiliac joints (SIJ) of 25% of healthy individuals and mechanical back pain patients, challenging the imaging discrimination from early spondyloarthritis (SpA). It is unknown whether stress injury in competition sports may trigger BME. We explored frequency and anatomical distribution of SIJ MRI lesions in recreational and elite athletes. After pre-test calibration, semicoronal SIJ MRI scans of 20 recreational runners (RR) before/after running and 22 elite ice-hockey players (IP) were assessed by 3 blinded readers for BME and structural lesions using an SIJ quadrant-based module. Scans of TNF-treated SpA patients served to mask readers. Readers recorded subjects meeting the ASAS definition for active sacroiliitis. Descriptive analysis comprised frequency of SIJ quadrants with BME/structural lesions and their distribution in 8 anatomical SIJ regions: upper/lower ilium and sacrum, subdivided in anterior/posterior slices, as concordantly recorded by ≥2/3 readers. The proportions in RR/IP fulfilling the ASAS definition concordantly by ≥2/3 readers were 30-35%/41%. The mean number (SD) of SIJ quadrants showing BME was 3.1 (4.2)/3.1 (4.5) in RR before/after running, and 3.6 (3.0) in IP. The posterior lower ilium was the single most affected SIJ region, followed by the anterior upper sacrum. Erosion was virtually absent. In recreational and elite athletes, BME showed on average in 3-4 SIJ quadrants, meeting the ASAS definition in 30%-41%. The posterior lower ilium was the single most affected SIJ region. These findings in athletes help refine data-driven thresholds for defining sacroiliitis in early SpA. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  11. Distribuição de frequência da chuva para região Centro-Sul do Ceará, Brasil Frequency distribution of rainfall for the South-Central region of Ceará, Brazil

    Directory of Open Access Journals (Sweden)

    Ítalo Nunes Silva

    2013-09-01

    Full Text Available Foram analisadas sete distribuições de probabilidade Exponencial, Gama, Log-normal, Normal, Weibull, Gumbel e Beta para a chuva mensal e anual na região Centro-Sul do Ceará, Brasil. Para verificação dos ajustes dos dados às funções densidade de probabilidade foi utilizado o teste não-paramétrico de Kolmogorov-Smirnov com nível de 5% de significância. Os dados de chuva foram obtidos da base de dados da SUDENE registrados durante o período de 1913 a 1989. Para a chuva total anual teve ajuste satisfatório dos dados às distribuições Gama, Gumbel, Normal e Weibull e não ocorreu ajuste às distribuições Exponencial, Log-normal e Beta. Recomenda-se o uso da distribuição Normal para estimar valores de chuva provável anual para a região, por ser um procedimento de fácil aplicação e também pelo bom desempenho nos testes. A distribuição de frequência Gumbel foi a que melhor representou os dados de chuva para o período mensal, com o maior número de ajustes no período chuvoso. No período seco os dados de chuva foram melhores representados pela distribuição Exponencial.Seven probability distributions were analysed: Exponential, Gamma, Log-Normal, Normal, Weibull, Gumbel and Beta, for monthly and annual rainfall in the south-central region of Ceará, Brazil. In order to verify the adjustments of the data to the probability density functions, the non-parametric Kolmogorov-Smirnov test was used with a 5% level of significance. The rainfall data were obtained from the database at SUDENE, recorded from 1913 to 1989. For the total annual rainfall, adjustment of the data to the Gamma, Gumbel, Normal and Weibull distributions was satisfactory, and there was no adjustment to the Exponential, Log-normal and Beta distributions. Use of Normal distribution is recommended to estimate the values of probable annual rainfall in the region, this being a procedure of easy application, performing well in the tests. The Gumbel frequency

  12. Primary Frequency Response with Aggregated DERs: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Guggilam, Swaroop S.; Dhople, Sairaj V.; Zhao, Changhong; Dall' Anese, Emiliano; Chen, Yu Christine

    2017-03-03

    Power networks have to withstand a variety of disturbances that affect system frequency, and the problem is compounded with the increasing integration of intermittent renewable generation. Following a large-signal generation or load disturbance, system frequency is arrested leveraging primary frequency control provided by governor action in synchronous generators. In this work, we propose a framework for distributed energy resources (DERs) deployed in distribution networks to provide (supplemental) primary frequency response. Particularly, we demonstrate how power-frequency droop slopes for individual DERs can be designed so that the distribution feeder presents a guaranteed frequency-regulation characteristic at the feeder head. Furthermore, the droop slopes are engineered such that injections of individual DERs conform to a well-defined fairness objective that does not penalize them for their location on the distribution feeder. Time-domain simulations for an illustrative network composed of a combined transmission network and distribution network with frequency-responsive DERs are provided to validate the approach.

  13. Multicritical phase diagrams of the ferromagnetic spin-3/2 Blume-Emery-Griffiths model with repulsive biquadratic coupling including metastable phases: The cluster variation method and the path probability method with the point distribution

    Energy Technology Data Exchange (ETDEWEB)

    Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)], E-mail: keskin@erciyes.edu.tr; Canko, Osman [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

    2008-01-15

    We study the thermal variations of the ferromagnetic spin-3/2 Blume-Emery-Griffiths (BEG) model with repulsive biquadratic coupling by using the lowest approximation of the cluster variation method (LACVM) in the absence and presence of the external magnetic field. We obtain metastable and unstable branches of the order parameters besides the stable branches and phase transitions of these branches are investigated extensively. The classification of the stable, metastable and unstable states is made by comparing the free energy values of these states. We also study the dynamics of the model by using the path probability method (PPM) with the point distribution in order to make sure that we find and define the metastable and unstable branches of the order parameters completely and correctly. We present the metastable phase diagrams in addition to the equilibrium phase diagrams in the (kT/J, K/J) and (kT/J, D/J) planes. It is found that the metastable phase diagrams always exist at the low temperatures, which are consistent with experimental and theoretical works.

  14. Multicritical phase diagrams of the ferromagnetic spin-3/2 Blume-Emery-Griffiths model with repulsive biquadratic coupling including metastable phases: The cluster variation method and the path probability method with the point distribution

    International Nuclear Information System (INIS)

    Keskin, Mustafa; Canko, Osman

    2008-01-01

    We study the thermal variations of the ferromagnetic spin-3/2 Blume-Emery-Griffiths (BEG) model with repulsive biquadratic coupling by using the lowest approximation of the cluster variation method (LACVM) in the absence and presence of the external magnetic field. We obtain metastable and unstable branches of the order parameters besides the stable branches and phase transitions of these branches are investigated extensively. The classification of the stable, metastable and unstable states is made by comparing the free energy values of these states. We also study the dynamics of the model by using the path probability method (PPM) with the point distribution in order to make sure that we find and define the metastable and unstable branches of the order parameters completely and correctly. We present the metastable phase diagrams in addition to the equilibrium phase diagrams in the (kT/J, K/J) and (kT/J, D/J) planes. It is found that the metastable phase diagrams always exist at the low temperatures, which are consistent with experimental and theoretical works

  15. Single frequency semiconductor lasers

    CERN Document Server

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui

    2017-01-01

    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  16. UBICACIÓN ÓPTIMA DE RECONECTADORES EN SISTEMAS DE DISTRIBUCIÓN PARA MINIMIZAR LA FRECUENCIA MEDIA DE INTERRUPCIÓN OPTIMAL LOCATION OF RECLOSERS IN DISTRIBUTION NETWORKS IN ORDER TO MINIMIZE THE AVERAGE INTERRUPTION FREQUENCY

    Directory of Open Access Journals (Sweden)

    Jerson Reyes S

    2009-08-01

    Full Text Available En este trabajo se presenta una metodología para minimizar la frecuencia de fallas en Sistemas de Distribución radiales considerando una carga uniformemente distribuida. Se utiliza una aproximación lineal para la ubicación de reconectadores. Este trabajo basa su estudio en la minimización del índice de Frecuencia Media de Interrupción por Potencia instalada, el cual es utilizado como parámetro de regulación y clasificación de las compañías distribuidoras chilenas, según la reglamentación eléctrica vigente. Se introduce además el concepto de Factor de Distancia entre línea Troncal y arranque, el cual puede ser utilizado como herramienta de discriminación para acotar el número de reconectadores a instalar en la línea troncal. Además permite discriminar en base a la data histórica de la línea, si un arranque cualquiera, debe ser evaluado económicamente, como un nuevo alimentador, de forma tal que el índice Frecuencia Media de Interrupción por Potencia instalada sea minimizado.This paper presents a framework for minimizing the average interruption frequency in radial Distribution Systems with uniformly distributed loads. Here, the position of the reclosers has been modeled using a linear approximation. The objective of this paper is to minimize the average interruption frequency per installed power. According to the current electric regulation in Chile, this index is the metric used to regulate and classify the performance of utilities. In the analysis a novel concept of Distance Factor between the main feeder and a branch feeder was introduced. This concept can be utilized as a theoretical limit for the number of switches to install on the main feeder. In addition, based upon the service history of the line, the distance factor determines if a certain line must be economically assessed like a new feeder so that the aforementioned performance index of average interruption frequency per installed power is minimized.

  17. Induction heating of gears - pulsing dual-frequency concept

    Directory of Open Access Journals (Sweden)

    R. Przyłucki

    2013-04-01

    Full Text Available The paper concerns analysis of gears hardening process. In order to obtain required temperature distribution several variations of single and combined frequencies for selected gear-wheel configurations were considered. The paper includes the calculation models and analysis of geometry and current intensity as well frequency influence on temperature distribution of the tooth surface. All calculations have been carried out by means of the use of Flux3D simulation program, which enables to provide, coupled electromagnetic and temperature fields analysis.

  18. Geographical distribution of bat flies (Diptera: Nycteribiidae and Streblidae), including two new records, Nycteribia allotopa and N. formosana, collected from bats (Chiroptera: Rhinolophidae and Vespertilionidae) in the Republic of Korea.

    Science.gov (United States)

    Kim, Heung Chul; Han, Sang Hoon; Dick, Carl W; Choi, Yong Gun; Chong, Sung Tae; Klein, Terry A; Rueda, Leopoldo M

    2012-12-01

    As part of the 65(th) Medical Brigade, U.S. Army, arthropod-borne disease surveillance program and in collaboration with the Korea National Institute of Biological Resources (NIBR), bats were captured from caves and abandoned mines in the Republic of Korea. A total of 39 adult bat flies including five species of Nycteribiidae [Penicillidia jenynsii, Nycteribia parvula, N. formosana, N. allotopa mikado, and an unidentified species of Nycteribia (N. cf. formosana)], and one species of Streblidae, Brachytarsina kanoi, were collected from bats belonging to two families, Rhinolophidae and Vespertilionidae. This is the first report of N. allotopa mikado and N. formosana from the Republic of Korea. © 2012 The Society for Vector Ecology.

  19. Organic-Carbon Sequestration in Soil/Sediment of the Mississippi River Deltaic Plain - Data; Landscape Distribution, Storage, and Inventory; Accumulation Rates; and Recent Loss, Including a Post-Katrina Preliminary Analysis (Chapter B)

    Science.gov (United States)

    Markewich, Helaine W.; Buell, Gary R.; Britsch, Louis D.; McGeehin, John P.; Robbins, John A.; Wrenn, John H.; Dillon, Douglas L.; Fries, Terry L.; Morehead, Nancy R.

    2007-01-01

    Soil/sediment of the Mississippi River deltaic plain (MRDP) in southeastern Louisiana is rich in organic carbon (OC). The MRDP contains about 2 percent of all OC in the surface meter of soil/sediment in the Mississippi River Basin (MRB). Environments within the MRDP differ in soil/sediment organic carbon (SOC) accumulation rate, storage, and inventory. The focus of this study was twofold: (1) develop a database for OC and bulk density for MRDP soil/sediment; and (2) estimate SOC storage, inventory, and accumulation rates for the dominant environments (brackish, intermediate, and fresh marsh; natural levee; distributary; backswamp; and swamp) in the MRDP. Comparative studies were conducted to determine which field and laboratory methods result in the most accurate and reproducible bulk-density values for each marsh environment. Sampling methods included push-core, vibracore, peat borer, and Hargis1 sampler. Bulk-density data for cores taken by the 'short push-core method' proved to be more internally consistent than data for samples collected by other methods. Laboratory methods to estimate OC concentration and inorganic-constituent concentration included mass spectrometry, coulometry, and loss-on-ignition. For the sampled MRDP environments, these methods were comparable. SOC storage was calculated for each core with adequate OC and bulk-density data. SOC inventory was calculated using core-specific data from this study and available published and unpublished pedon data linked to SSURGO2 map units. Sample age was estimated using isotopic cesium (137Cs), lead (210Pb), and carbon (14C), elemental Pb, palynomorphs, other stratigraphic markers, and written history. SOC accumulation rates were estimated for each core with adequate age data. Cesium-137 profiles for marsh soil/sediment are the least ambiguous. Levee and distributary 137Cs profiles show the effects of intermittent allochthonous input and/or sediment resuspension. Cesium-137 and 210Pb data gave the most

  20. Transport accident frequency data, their sources and their application in risk assessment

    International Nuclear Information System (INIS)

    Appleton, P.R.

    1988-08-01

    Base transport accident frequency data and sources of these data are presented. Both generic information and rates specific to particular routes or packages are included. Strong packages, such as those containing significant quantities of radioactive materials, will survive most of the accidents represented by these base frequencies without a containment breach. The association of severity probability distributions with a base frequency, and package and contents response, leading to the quantification of release frequency and magnitude, are often more important in risk assessment than the base frequency itself. This paper therefore also includes brief comments on techniques adopted to utilize the base frequencies. This paper reports an accident frequency data survey undertaken at the end of 1986. It has not been updated to take account of work published between January 1987 and the Report publication date. (author)

  1. Collision Frequency for Energy Transfer in Unimolecular Reactions.

    Science.gov (United States)

    Matsugi, Akira

    2018-03-01

    Pressure dependence of unimolecular reaction rates is governed by the energy transfer in collisions of reactants with bath gas molecules. Pressure-dependent rate constants can be theoretically determined by solving master equations for unimolecular reactions. In general, master equation formulations describe energy transfer processes using a collision frequency and a probability distribution model of the energy transferred per collision. The present study proposes a novel method for determining the collision frequency from the results of classical trajectory calculations. Classical trajectories for collisions of several polyatomic molecules (ethane, methane, tetrafluoromethane, and cyclohexane) with monatomic colliders (Ar, Kr, and Xe) were calculated on potential energy surfaces described by the third-order density-functional tight-binding method in combination with simple pairwise interaction potentials. Low-order (including non-integer-order) moments of the energy transferred in deactivating collisions were extracted from the trajectories and compared with those derived using some probability distribution models. The comparison demonstrates the inadequacy of the conventional Lennard-Jones collision model for representing the collision frequency and suggests a robust method for evaluating the collision frequency that is consistent with a given probability distribution model, such as the exponential-down model. The resulting collision frequencies for the exponential-down model are substantially higher than the Lennard-Jones collision frequencies and are close to the (hypothetical) capture rate constants for dispersion interactions. The practical adequacy of the exponential-down model is also briefly discussed.

  2. Design optimization of ideal non-imaging concentrators for solar collectors by use of yearly insolation model with frequency distribution; Dosu bunpu wo koryoshita nenkan nissha model ni yoru shunetsuyo riso hikessho shukoki no saitekika

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, A. [Tokyo University of Agriculture and Technology, Tokyo (Japan)

    1996-10-27

    Optimization was carried out for the 2D-CPC (compound parabolic concentrator) known as an ideal 2-dimensional non-imaging concentrator for its application to stationary solar heat concentrators. A non-imaging optical system is a system that has an angle for incident light called an acceptance angle, and is treated as an effective tool in the field of solar energy application. Analysis was conducted from the viewpoint of energy and exergy on the presumption of constant temperature operation. For the analysis of constant temperature heat concentration, it needs to be presumed that heat concentrators are in operation only in the presence of insolation that is more than a specified level (critical insolation). When the acceptance angle is fixed for optimization, energy efficiency does not have a peak with respect to the critical probability insolation intensity (in a probability model considering frequency distribution). On the other hand, for the optimization of exergy efficiency, the half-acceptance angle should be within a 35-40{degree} range (agreeing with the optimum angle cost-wise), and the critical probability insolation should be set at 250-300W/m{sup 2} (1/4 of the maximum insolation intensity). The obtained results are low in model dependency and are sufficiently reliable. 14 refs., 4 figs.

  3. Further Molecular Analysis of G6PD Deficiency Variants in Southern Vietnam and a Novel Variant Designated as G6PD Ho Chi Minh (173 A>G; 58 Asp>Gly): Frequency Distributions of Variants Compared with Those in Other Southeast Asian Countries.

    Science.gov (United States)

    Kawamoto, Fumihiko; Matsuoka, Hiroyuki; Pham, Nghiem Minh; Hayashi, Taeko; Kasahara, Yuichi; Dung, Nguyen The; Kido, Yasutoshi; Kanbe, Toshio; Tantular, Indah S

    2017-08-01

    We conducted a survey of glucose-6-phosphate dehydrogenase (G6PD) deficiency among newborn babies at Tu Du Hospital, Ho Chi Minh, southern Vietnam. A total of 90 deficient babies were detected, including 85 in the Kinh ethnic group, 4 Chinese, and 1 in the K'Ho minority group. In the Kinh ethnic group, G6PD variants such as G6PD Viangchan (n=32), Kaiping (n=11), Canton (n=8), Chinese-5 (n=7), Union (n=5) and Quing Yuan (n=4) were detected. A variant with silent mutations at 1311 C>T and IVS11 nt 93 T>C was also detected in 17 cases. A novel mutation (173 A>G) in exon 4 with a predicted amino acid change of 58 Asp>Gly was also found in a Kinh newborn girl and her father, and it was designated as G6PD Ho Chi Minh. These findings demonstrated that the Kinh ethnic group in southern Vietnam has 8 different G6PD variants, indicating that the members of this group have many ancestors in terms of G6PD variants from Southeast Asia, China, and Oceania. We compared the frequency distribution of G6PD variants in the Kinh population with those of other Southeast Asian populations, and the Kinh population's distribution was quite similar to that in the Thai population, but differed from it by the absence of G6PD Mahidol.

  4. [Statistical analysis on andrological patients. I. Frequencies].

    Science.gov (United States)

    Nebe, K H; Schirren, C

    1980-01-01

    According a collective of 1619 andrological patients of the year 1975 some statistical data were given: age distribution, frequencies, frequency of sexual intercourse, anticonception and relation to age, coitus frequency and relation to age, impotence and relation to age, previous andrological treatment.

  5. Characteristic frequencies of a non-Maxwellian plasma - A method for localizing the exact frequencies of magnetospheric intense natural waves near fpe

    International Nuclear Information System (INIS)

    Belmont, G.

    1981-01-01

    Intense natural waves are commonly observed onboard satellites in the outer earth's magnetosphere, inside a narrow frequency range, including the electron plasma and upper hybrid frequencies. In order to progress in the understanding of their emission processes, it is necessary to determine precisely the relationship which exists between their frequencies and the characteristic frequencies of the magnetospheric plasma. For this purpose, it is necessary to take into account the fact that some of these characteristic frequencies, which are provided by active sounding of the plasma, not only depend on the total density, but also on the shape of the distribution function (which has generally been assumed to be Maxwellian). A method providing a fine diagnosis of general non-Maxwellian plasmas is developed. This method of analysis of the experimental data is based on a theoretical study which points out the influence of the shape of the distribution function on the dispersion curves (for wave vectors perpendicular to the static magnetic field)

  6. Optical distribution of local oscillators in future telecommunication satellite payloads

    Science.gov (United States)

    Benazet, Benoît; Sotom, Michel; Maignan, Michel; Berthon, Jacques

    2017-11-01

    The distribution of high spectral purity reference signals over optical fibre in future telecommunication satellite payloads is presented. Several types of applications are considered, including the distribution of a reference frequency at 10 MHz (Ultra-Stable Reference Oscillator) as well as the distribution of a radiofrequency oscillator around 800 MHz (Master Local Oscillator). The results of both experimental and theoretical studies are reported. In order to meet phase noise requirements for the USRO distribution, the use of an optimised receiver circuit based on an optically synchronised oscillator is investigated. Finally, the optical distribution of microwave local oscillators at frequencies exceeding 20 GHz is described. Such a scheme paves the way to more advanced sub-systems involving optical frequency-mixing and optical transmission of microwave signals, with applications to multiple-beam active antennas.

  7. Variable frequency iteration MPPT for resonant power converters

    Science.gov (United States)

    Zhang, Qian; Bataresh, Issa; Chen, Lin

    2015-06-30

    A method of maximum power point tracking (MPPT) uses an MPPT algorithm to determine a switching frequency for a resonant power converter, including initializing by setting an initial boundary frequency range that is divided into initial frequency sub-ranges bounded by initial frequencies including an initial center frequency and first and second initial bounding frequencies. A first iteration includes measuring initial powers at the initial frequencies to determine a maximum power initial frequency that is used to set a first reduced frequency search range centered or bounded by the maximum power initial frequency including at least a first additional bounding frequency. A second iteration includes calculating first and second center frequencies by averaging adjacent frequent values in the first reduced frequency search range and measuring second power values at the first and second center frequencies. The switching frequency is determined from measured power values including the second power values.

  8. Differences in genotype and allele frequency distributions of polymorphic drug metabolizing enzymes CYP2C19 and CYP2D6 in mainland Chinese Mongolian, Hui and Han populations.

    Science.gov (United States)

    Yin, S-J; Ni, Y-B; Wang, S-M; Wang, X; Lou, Y-Q; Zhang, G-L

    2012-06-01

    Cytochrome P450 2C19 (CYP2C19) and CYP2D6 are important xenobiotic metabolic enzymes and both show considerable genetic variability between Orientals and Caucasians. There are known marked heterogeneity in susceptibility to various cancers and hypertension among Chinese Mongolian, Hui and Han ethnic groups, but the molecular mechanisms are unknown. Our objective was to investigate the patterns of distribution of CYP2C19 and CYP2D6 polymorphisms among healthy Chinese subjects to determine whether any observed inter-ethnic variability might be worth further investigation as possible contributors to the known differences in disease prevalence. Blood samples were collected from 454 unrelated Chinese healthy subjects (214 Han, 111 Hui, 129 Mongolian) for genotyping analysis. The single nucleotide polymorphisms (SNPs) CYP2C19*2 (681G>A in exon 5), CYP2C19*3 (636G>A in exon 4) and CYP2D6*10 (188C>T in exon 1) were determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Significantly higher frequencies of the CYP2C19 poor metabolic genotypes were observed in Chinese Han (18·7%), Chinese Hui (25·0%) and Chinese Mongolian (10·9%) subjects than has been reported for Caucasians (1·7-3·0%, P Hui (32·4%) and Han (29·7%) than in Chinese Mongolian (18·2%, P Hui ethnic groups than have been reported for Caucasians (11·1-16·3% and 0-0·2%, P Hui (40·6% and 30·7%) and Mongolian subjects (31·3% and 9·6%, both P Hui and Han populations. These differences may be important in explaining reported inter-ethnic differences in disease prevalence and response to drugs. © 2011 Blackwell Publishing Ltd.

  9. Frequency and Distribution of Single-Nucleotide Polymorphisms within mprF in Methicillin-Resistant Staphylococcus aureus Clinical Isolates and Their Role in Cross-Resistance to Daptomycin and Host Defense Antimicrobial Peptides.

    Science.gov (United States)

    Bayer, Arnold S; Mishra, Nagendra N; Chen, Liang; Kreiswirth, Barry N; Rubio, Aileen; Yang, Soo-Jin

    2015-08-01

    MprF is responsible for the lysinylation of phosphatidylglycerol (PG) to synthesize the positively charged phospholipid (PL) species, lysyl-PG (L-PG). It has been proposed that the single-nucleotide polymorphisms (SNPs) within the mprF open reading frame (ORF) are associated with a gain-in-function phenotype in terms of daptomycin resistance in Staphylococcus aureus. (Note that although the official term is daptomycin nonsusceptibility, we use the term daptomycin resistance in this paper for ease of presentation.) Using 22 daptomycin-susceptible (DAP(s))/daptomycin-resistant (DAP(r)) clinical methicillin-resistant S. aureus (MRSA) strain pairs, we assessed (i) the frequencies and distribution of putative mprF gain-in-function SNPs, (ii) the relationships of the SNPs to both daptomycin resistance and cross-resistance to the prototypical endovascular host defense peptide (HDP) thrombin-induced platelet microbicidal protein (tPMP), and (iii) the impact of mprF SNPs on positive surface charge phenotype and modifications of membrane PL profiles. Most of the mprF SNPs identified in our DAP(r) strains were clustered within the two MprF loci, (i) the central bifunctional domain and (ii) the C-terminal synthase domain. Moreover, we were able to correlate the presence and location of mprF SNPs in DAP(r) strains with HDP cross-resistance, positive surface charge, and L-PG profiles. Although DAP(r) strains with mprF SNPs in the bifunctional domain showed higher resistance to tPMPs than DAP(r) strains with SNPs in the synthase domain, this relationship was not observed in positive surface charge assays. These results demonstrated that both charge-mediated and -unrelated mechanisms are involved in DAP resistance and HDP cross-resistance in S. aureus. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  10. Robust laser frequency stabilization by serrodyne modulation.

    Science.gov (United States)

    Kohlhaas, Ralf; Vanderbruggen, Thomas; Bernon, Simon; Bertoldi, Andrea; Landragin, Arnaud; Bouyer, Philippe

    2012-03-15

    We report the relative frequency stabilization of a distributed feedback erbium-doped fiber laser on an optical cavity by serrodyne frequency shifting. A correction bandwidth of 2.3 MHz and a dynamic range of 220 MHz are achieved, which leads to a strong robustness against large disturbances up to high frequencies. We demonstrate that serrodyne frequency shifting reaches a higher correction bandwidth and lower relative frequency noise level compared to a standard acousto-optical modulator based scheme. Our results allow us to consider promising applications in the absolute frequency stabilization of lasers on optical cavities.

  11. Food frequency questionnaires.

    Science.gov (United States)

    Pérez Rodrigo, Carmen; Aranceta, Javier; Salvador, Gemma; Varela-Moreiras, Gregorio

    2015-02-26

    Food Frequency Questionnaires are dietary assessment tools widely used in epidemiological studies investigating the relationship between dietary intake and disease or risk factors since the early '90s. The three main components of these questionnaires are the list of foods, frequency of consumption and the portion size consumed. The food list should reflect the food habits of the study population at the time the data is collected. The frequency of consumption may be asked by open ended questions or by presenting frequency categories. Qualitative Food Frequency Questionnaires do not ask about the consumed portions; semi-quantitative include standard portions and quantitative questionnaires ask respondents to estimate the portion size consumed either in household measures or grams. The latter implies a greater participant burden. Some versions include only close-ended questions in a standardized format, while others add an open section with questions about some specific food habits and practices and admit additions to the food list for foods and beverages consumed which are not included. The method can be self-administered, on paper or web-based, or interview administered either face-to-face or by telephone. Due to the standard format, especially closed-ended versions, and method of administration, FFQs are highly cost-effective thus encouraging its widespread use in large scale epidemiological cohort studies and also in other study designs. Coding and processing data collected is also less costly and requires less nutrition expertise compared to other dietary intake assessment methods. However, the main limitations are systematic errors and biases in estimates. Important efforts are being developed to improve the quality of the information. It has been recommended the use of FFQs with other methods thus enabling the adjustments required. Copyright AULA MEDICA EDICIONES 2015. Published by AULA MEDICA. All rights reserved.

  12. NASA's EOSDIS has a large amount of Earth science data in its archives, distributed through discipline-specific DAACs. We will demonstrate the use of NASA Earth science data in a GIS to include a diverse amount of formats, missions, instruments, and applications that has become more and more user-friendly and interoperable in the last several years.

    Science.gov (United States)

    Bagwell, R.; Peters, B.; Berrick, S. W.

    2017-12-01

    Over the last several decades, numerous satellite missions have been and continue to be conducted in support of Earth science. The data collected during these campaigns have a wide variety of uses including model assessment, decision support applications, and basic and applied research. NASA's Earth Observing System Data and Information System (EOSDIS) has a large amount of Earth science data within its archives, managed and distributed through its discipline-specific Distributed Active Archive Centers (DAACs). The amount of data in the EOSDIS archive is expected to grow significantly over the next decade. Data users rely on accessing and using these data within a Geographical Information System (GIS). This provides the ability for data users to do more with these data. We intend to demonstrate the use of NASA Earth science data within a GIS to include a diverse amount of formats, missions, instruments, and applications that has become more and more user-friendly and interoperable in the last several years.

  13. Nuclear resonance apparatus including means for rotating a magnetic field

    International Nuclear Information System (INIS)

    Sugimoto, H.

    1983-01-01

    A nuclear magnetic resonance apparatus including magnet apparatus for generating a homogeneous static magnetic field between its magnetic poles, shims of a magnetic substance mounted on the magnetic poles to apply a first gradient magnetic field intensity distribution in a direction orthogonal as to the direction of line of magnetic force of the static magnetic field, gradient magnetic field generating electromagnetic apparatus for generating a second gradient magnetic field having a gradient magnetic field intensity distribution in superimposition with the static magnetic field and for changing the magnetic field gradient of the first gradient magnetic field, an oscillator for generating an oscillating output having a frequency corresponding to the nuclear magnetic resonance condition of an atomic nucleus to be measured, a coil wound around a body to be examined for applying the output of said oscillator as electromagnetic waves upon the body, a receiver for detecting the nuclear magnetic resonance signals received by the coil, a gradient magnetic field controller making a magnetic field line equivalent to the combined gradient magnetic fields and for rotating the line along the section of the body to be examined by controlling said gradient magnetic field generating electromagnetic apparatus and devices for recording the nuclear magnetic resonance signals, for reconstructing the concentration distribution of the specific atomic nuclei in the section of the body, and a display unit for depicting the result of reconstruction

  14. Frequency dependent polarization in blazars

    International Nuclear Information System (INIS)

    Bjoernsson, C.I.

    1984-10-01

    It is argued that the intrinsic frequency dependent polarization in blazars finds its most straightforward explanations in terms of a single rather than a multicomponent sourcemodel. In order to reproduce the observations, under the assumption that the emission mechanism is optically thin synchrotron radiation, both a well ordered magnetic field and an electron distribution with a sharp break or cuttoff are necessary. Non-uniform pitch angle distribution and/or environments where synchrotron losses are important are both conducive to producing strong frequency dependent polarization. Reasons are put forth as to why such conditions ar expected to occur in blazars. Two specific models are discussed in detail and it is shown that they are both able to produce strong frequency dependent polarization, even when the spectral index changes by a small amount only. (orig.)

  15. The instantaneous frequency rate spectrogram

    Science.gov (United States)

    Czarnecki, Krzysztof

    2016-01-01

    An accelerogram of the instantaneous phase of signal components referred to as an instantaneous frequency rate spectrogram (IFRS) is presented as a joint time-frequency distribution. The distribution is directly obtained by processing the short-time Fourier transform (STFT) locally. A novel approach to amplitude demodulation based upon the reassignment method is introduced as a useful by-product. Additionally, an estimator of energy density versus the instantaneous frequency rate (IFR) is proposed and referred to as the IFR profile. The energy density is estimated based upon both the classical energy spectrogram and the IFRS smoothened by the median filter. Moreover, the impact of an analyzing window width, additive white Gaussian noise and observation time is tested. Finally, the introduced method is used for the analysis of the acoustic emission of an automotive engine. The recording of the engine of a Lamborghini Gallardo is analyzed as an example.

  16. Fast frequency divider circuit using combinational logic

    Energy Technology Data Exchange (ETDEWEB)

    Helinski, Ryan

    2017-05-30

    The various technologies presented herein relate to performing on-chip frequency division of an operating frequency of a ring oscillator (RO). Per the various embodiments herein, a conflict between RO size versus operational frequency can be addressed by dividing the output frequency of the RO to a frequency that can be measured on-chip. A frequency divider circuit (comprising NOR gates and latches, for example) can be utilized in conjunction with the RO on the chip. In an embodiment, the frequency divider circuit can include a pair of latches coupled to the RO to facilitate dividing the oscillating frequency of the RO by 2. In another embodiment, the frequency divider circuit can include four latches (operating in pairs) coupled to the RO to facilitate dividing the oscillating frequency of the RO by 4. A plurality of ROs can be MUXed to the plurality of ROs by a single oscillation-counting circuit.

  17. Fixed bin frequency distribution for the VNTR Loci D2S44, D4S139, D5S110, and D8S358 in a population sample from Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Parreira Kleber Simônio

    2002-01-01

    Full Text Available Fixed bin frequencies for the VNTR loci D2S44, D4S139, D5S110, and D8S358 were determined in a Minas Gerais population sample. The data were generated by RFLP analysis of HaeIII-digested genomic DNA and chemiluminescent detection. The four VNTR loci have met Hardy-Weinberg equilibrium, and there was no association of alleles among VNTR loci. The frequency data can be used in forensic analyses and paternity tests to estimate the frequency of a DNA profile in the general Brazilian population.

  18. [Frequency of skin reactivity to food allergens in allergic patients].

    Science.gov (United States)

    Camero-Martínez, Heriberto; López-García, Aída Inés; Rivero-Yeverino, Daniela; Caballero-López, Chrystopherson Gengyny; Arana-Muñoz, Oswaldo; Papaqui-Tapia, Sergio; Rojas-Méndez, Isabel Cristina; Vázquez-Rojas, Elizabeth

    2017-01-01

    Food allergy is deemed to have a worldwide prevalence ranging from 2 to 10 %. To determine the frequency of skin reactivity to food allergens by age groups. Cross-sectional, descriptive, prolective, observational study. Patients aged from 2 to 64 years with symptoms consistent with allergic disease were included. Skin prick tests were carried out with food allergens. Frequencies and percentages were estimated. One-hundred and ninety-one patients were included, out of which 63.4% were females. Mean age was 22.5 years; 19.3 % showed positive skin reactivity to at least one food. Distribution by age group was as follows: preschool children 13.5 %, schoolchildren 24.3 %, adolescents 2.7 % and adults 59.5 %. Diagnoses included allergic rhinitis in 84.3 %, asthma in 19.4 %, urticaria in 14.1 % and atopic dermatitis in 8.4 %. Positive skin reactivity frequency distribution in descending order was: soybeans with 5.2 %, peach with 4.7 %, grapes, orange and apple with 3.6 %, nuts with 3.1 %, pineapple, avocado, tomato and tuna with 2.6 %. The frequency of skin reactivity to food allergens was similar to that reported in the national and Latin American literature, but sensitization to each specific allergen varied for each age group.

  19. Frequency noise in frequency swept fiber laser

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2013-01-01

    This Letter presents a measurement of the spectral content of frequency shifted pulses generated by a lightwave synthesized frequency sweeper. We found that each pulse is shifted in frequency with very high accuracy. We also discovered that noise originating from light leaking through the acousto...

  20. Broadcast Communication by System Frequency Modulation

    DEFF Research Database (Denmark)

    Douglass, Philip James; You, Shi; Heussen, Kai

    2012-01-01

    Load controllers available today can measure AC system frequency and react to frequency deviations. A system operator can communicate to frequency sensitive loads by changing the set-points of the system’s dispatchable frequency regulation resources. Explicitly signaling system state by generating...... off-nominal system frequency values is a novel narrowband broadcast communications channel between system operators and frequency sensitive distributed energy resources (FS-DER). The feasibility of the proposed system is evaluated on an existing island power system in Denmark. This study shows...... that within standard frequency quality constraints, 4 distinct symbols are feasible on the island. However, the overarching imperative of system stability prevents the symbols from having arbitrary meanings. Higher frequency values must translate into greater consumption from loads, and vice versa. Within...

  1. Distribuição fenotípica e a freqüência genotípica do sistema sangüíneo Duffy em pacientes com a doença de Jorge Lobo Phenotypic distribution and genotypic frequency of the Duffy blood group system in Jorge Lobo's disease patients

    Directory of Open Access Journals (Sweden)

    Eliane A. Silva

    2006-12-01

    elaborar tabelas de freqüências fenotípicas para a população acometida pela doença de Jorge Lobo, bem como realizar pesquisas para melhor entendimento da função biológica dos antígenos do sistema Duffy.Jorge Lobo's disease is a chronic cutaneous-subcutaneous mycosis caused by the fungus Lacazia loboi. The mechanisms involved in susceptibility and resistance to infection by this pathogen, especially genetic background, are yet to be understood. The objective of the present study was to evaluate the phenotypic distribution of the Duffy blood group in Jorge Lobo's disease patients and calculate its gene frequencies. Twenty one patients were analyzed, among them 13 Caucasoid and 8 from mixed ethnical backgrounds (Afro-Brazilians originating from the State of Acre. The control group consisted of 44 healthy individuals from the city of Rio Branco (AC. The Duffy phenotype was defined by the presence of antigens in erythrocytes as visualized by the agglutination reaction of erythrocytes in the presence of anti-Fya and anti-Fyb antisera incubated at 37°C by the human antiglobulin test. Results showed that the phenotypic distribution of the Duffy blood group system in patients was significantly different from controls, with the frequency of individuals with phenotype Fy(a-b- being very high. Patients presented remarkably higher frequencies of the allele FY and ower frequencies of the allele FYA compared to controls. Frequencies of the allele FYB (not including non-expressed alleles were similar in both groups. The comparison between Duffy blood group distribution with clinical forms of the disease suggests predominance of the phenotype Fy(a-b+ in patients with the localized form of Jorge Lobo's disease, followed by phenotype Fy(a-b- and absence of phenotype (a+b-. On the other hand, we observed a higher incidence of phenotype Fy(a+b- in patients with the disseminated form of the disease. The multifocal forms were less expressive. Therefore, we may infer that the negative

  2. Radio Frequency Power Load and Associated Method

    Science.gov (United States)

    Srinivasan, V. Karthik (Inventor); Freestone, Todd M. (Inventor); Sims, William Herbert, III (Inventor)

    2014-01-01

    A radio frequency power load and associated method. A radio frequency power load apparatus may include a container with an ionized fluid therein. The apparatus may include one conductor immersed in a fluid and another conductor electrically connected to the container. A radio frequency transmission system may include a radio frequency transmitter, a radio frequency amplifier connected to the transmitter and a radio frequency power load apparatus connected to the amplifier. The apparatus may include a fluid having an ion source therein, one conductor immersed in a fluid, and another conductor electrically connected to the container. A method of dissipating power generated by a radio frequency transmission system may include constructing a waveguide with ionized fluid in a container and connecting the waveguide to an amplifier of the transmission system.

  3. Distributed systems

    CERN Document Server

    Van Steen, Maarten

    2017-01-01

    For this third edition of "Distributed Systems," the material has been thoroughly revised and extended, integrating principles and paradigms into nine chapters: 1. Introduction 2. Architectures 3. Processes 4. Communication 5. Naming 6. Coordination 7. Replication 8. Fault tolerance 9. Security A separation has been made between basic material and more specific subjects. The latter have been organized into boxed sections, which may be skipped on first reading. To assist in understanding the more algorithmic parts, example programs in Python have been included. The examples in the book leave out many details for readability, but the complete code is available through the book's Website, hosted at www.distributed-systems.net.

  4. Direct Load Control by AC Frequency Modulation

    DEFF Research Database (Denmark)

    Douglass, Philip James; You, Shi

    2012-01-01

    Fine-grained under frequency load shedding called “demand as a frequency controlled reserve“ (DFCR) has been shown to be a promising method of providingfrequency regulation service from distributed loads [1]. Micro-grids with a large portion of intermittent renewable generation will benefit greatly...

  5. Regional frequency analysis of extreme precipitation for Sicily (Italy)

    Science.gov (United States)

    Forestieri, Angelo; Blenkinsop, Stephen; Fowler, Hayley; Lo Conti, Francesco; Noto, Leonardo

    2016-04-01

    The analysis of extreme precipitation has always been included among most relevant hydrological applications because of the several important activities linked to the availability of tools for the estimation of extreme rainfall quantiles. These activities include the design of hydraulic civil structures and the evaluation and management of hydraulic and hydrological risk. In this study a frequency analysis of annual maxima precipitation measurements has been carried out for the area of Sicily (Italy). A typical hierarchical regional approach has been adopted for the parameter estimation procedure based on the L-moments method. The identification of homogeneous regions within the procedure has been pursued with a data driven procedure constituted by a principal component analysis of an ensemble of selected auxiliary variables, and a K-means cluster analysis algorithm. Auxiliary variables comprise meteo-climatic information and a representation of the average seasonal distribution of intense events. Results have been evaluated by means of a Monte Carlo experiment based on the comparison between at-site and regional fitted frequency distributions. Moreover, results have been compared with previous analyses performed for the same area. The study provides an updated tool for the modelling of extreme precipitation for the area of Sicily (Italy), with different features respect to previous tools both in terms of definition of homogeneous zones and in terms of parameters of the frequency distribution. Meteo-climatic information and the seasonality of extreme events retrieved from the dataset has been proficuously exploited in the analysis.

  6. Cooperative Game Study of Airlines Based on Flight Frequency Optimization

    Directory of Open Access Journals (Sweden)

    Wanming Liu

    2014-01-01

    Full Text Available By applying the game theory, the relationship between airline ticket price and optimal flight frequency is analyzed. The paper establishes the payoff matrix of the flight frequency in noncooperation scenario and flight frequency optimization model in cooperation scenario. The airline alliance profit distribution is converted into profit distribution game based on the cooperation game theory. The profit distribution game is proved to be convex, and there exists an optimal distribution strategy. The results show that joining the airline alliance can increase airline whole profit, the change of negotiated prices and cost is beneficial to profit distribution of large airlines, and the distribution result is in accordance with aviation development.

  7. Fluctuation-dissipation theorem for frequency-dependent specific heat

    DEFF Research Database (Denmark)

    Dyre, Jeppe; Nielsen, Johannes K.

    1996-01-01

    A derivation of the fluctuation-dissipation (FD) theorem for the frequency-dependent specific heat of a system described by a master equation is presented. The FD theorem is illustrated by a number of simple examples, including a system described by a linear Langevin equation, a two-level system......, and a system described by the energy master equation. It is shown that for two quite different models with low-energy cutoffs—a collection of two-level systems and a system described by the energy master equation—the frequency-dependent specific heat in dimensionless units becomes universal at low temperatures......, i.e., independent of both energy distribution and temperature. These two models give almost the same universal frequency-dependent specific heat, which compares favorably to experiments on supercooled alcohols....

  8. Integral Parameters of the Generalized Frequency Spectra of Moderators

    Energy Technology Data Exchange (ETDEWEB)

    Purohit, S.N.

    1966-06-15

    A study of the integral quantities - M{sub 2} (the second energy transfer moment of the scattering kernel weighted by the Maxwellian distribution), (v{sigma}{sub s}){sub min} (the minimum value of the scattering cross section times velocity) and the moments of frequency spectrum including the effective temperature and Debye-Waller integrals - in terms of the frequency spectrum of the dynamical modes is presented. Numerical results for H{sub 2}O, D{sub 2}O, Be, BeO and C using the available frequency spectra have been obtained. In the estimation of M{sub 2} and (v{sigma}{sub s}){sub min} the first term of the Placzek mass expansion is obtained exactly and the correction by the Doppler approximation method. In addition, the exact results for the Doppler approximation and the gas model have also been given.

  9. Radio Frequency Signal Propagation Study

    Science.gov (United States)

    2014-02-01

    and software solutions UNCLASSIFIED 5 UNCLASSIFIED DSTO-TR-2868 number of variables to select including the waveform used and whether the platform...the road. Transmission licences for the following five frequencies were obtained, 1216, 1270, 1399, 1525 and 1650 MHz. These frequencies were...Institution of Electrical Engineers, 2000 7. Matlab Software Package QPEM, Written by Richard Hawkes, APNT Group, CEWD, DSTO 8. Parsons, JD

  10. Non-Gaussian power grid frequency fluctuations characterized by Lévy-stable laws and superstatistics

    Science.gov (United States)

    Schäfer, Benjamin; Beck, Christian; Aihara, Kazuyuki; Witthaut, Dirk; Timme, Marc

    2018-02-01

    Multiple types of fluctuations impact the collective dynamics of power grids and thus challenge their robust operation. Fluctuations result from processes as different as dynamically changing demands, energy trading and an increasing share of renewable power feed-in. Here we analyse principles underlying the dynamics and statistics of power grid frequency fluctuations. Considering frequency time series for a range of power grids, including grids in North America, Japan and Europe, we find a strong deviation from Gaussianity best described as Lévy-stable and q-Gaussian distributions. We present a coarse framework to analytically characterize the impact of arbitrary noise distributions, as well as a superstatistical approach that systematically interprets heavy tails and skewed distributions. We identify energy trading as a substantial contribution to today's frequency fluctuations and effective damping of the grid as a controlling factor enabling reduction of fluctuation risks, with enhanced effects for small power grids.

  11. Multiple Frequency Parametric Sonar

    Science.gov (United States)

    2015-09-28

    300003 1 MULTIPLE FREQUENCY PARAMETRIC SONAR STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and...a method for increasing the bandwidth of a parametric sonar system by using multiple primary frequencies rather than only two primary frequencies...2) Description of Prior Art [0004] Parametric sonar generates narrow beams at low frequencies by projecting sound at two distinct primary

  12. Electron heating mode transition induced by mixing radio frequency and ultrahigh frequency dual frequency powers in capacitive discharges

    International Nuclear Information System (INIS)

    Sahu, B. B.; Han, Jeon G.

    2016-01-01

    Electron heating mode transitions induced by mixing the low- and high-frequency power in dual-frequency nitrogen discharges at 400 mTorr pressure are presented. As the low-frequency (13.56 MHz) power decreases and high-frequency (320 MHz) power increases for the fixed power of 200 W, there is a transition of electron energy distribution function (EEDF) from Druyvesteyn to bi-Maxwellian type characterized by a distinguished warm electron population. It is shown that this EEDF evolution is attributed to the transition from collisional to collisionless stochastic heating of the low-energy electrons.

  13. Multi-frequency excitation

    KAUST Repository

    Younis, Mohammad I.

    2016-03-10

    Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected for the device based on the natural frequency. Additionally, a second voltage amplitude of a second source of excitation can be selected for the device, and the first and second sources of excitation can be applied to the device. After applying the first and second sources of excitation, a frequency of the second source of excitation can be swept. Using the methods of multi- frequency excitation described herein, new operating frequencies, operating frequency ranges, resonance frequencies, resonance frequency ranges, and/or resonance responses can be achieved for devices and systems.

  14. Frequency selectivity at very low centre frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Marquardt, Torsten

    2010-01-01

    measurements based on OAE suppression techniques and notched-noise masking data psychophysically measured for centre frequencies in the range 50-125 Hz, this study examines how individual differences in frequency selectivity, as well as in masking, may occur at very low CFs due to individual differences...

  15. Frequency doubling crystals

    Science.gov (United States)

    Wang, Francis; Velsko, Stephan P.

    1989-01-01

    A systematic approach to the production of frequency conversion crystals is described in which a chiral molecule has attached to it a "harmonic generating unit" which contributes to the noncentrosymmetry of the molecule. Certain preferred embodiments of such harmonic generating units include carboxylate, guanadyly and imidazolyl units. Certain preferred crystals include L-arginine fluoride, deuterated L-arginine fluoride, L-arginine chloride monohydrate, L-arginine acetate, dithallium tartrate, ammonium N-acetyl valine, N-acetyl tyrosine and N-acetyl hydroxyproline. Chemical modifications of the chiral molecule, such as deuteration, halogenation and controlled counterion substitution are available to adapt the dispersive properties of a crystal in a particular wavelength region.

  16. Spatial Variation of Seismic B-Values of the Empirical Law of the Magnitude-Frequency Distribution from a Bayesian Approach Based On Spline (B-Spline) Function in the North Anatolian Fault Zone, North of Turkey

    Science.gov (United States)

    Türker, Tugba; Bayrak, Yusuf

    2017-12-01

    In this study, A Bayesian approach based on Spline (B-spline) function is used to estimate the spatial variations of the seismic b-values of the empirical law (G-R law) in the North Anatolian Fault Zone (NAFZ), North of Turkey. B-spline function method developed for estimation and interpolation of b-values. Spatial variations in b-values are known to reflect the stress field and can be used in earthquake hazard analysis. We proposed that b-values combined with seismicity and tectonic background. β=b*ln(10) function (the derivation of the G-R law) based on a Bayesian approach is used to estimate the b values and their standard deviations. A homogeneous instrumental catalog is used during the period 1900-2017. We divided into ten different seismic source regions based on epicenter distribution, tectonic, seismicity, faults in NAFZ. Three historical earthquakes (1343, MS = 7. 5, 1766, Ms=7.3, 1894, MS = 7. 0) are included in region 2 (Marmara Sea (Tekirdağ-Merkez-Kumburgaz-Çmarcik Basins)) where a large earthquake is expected in the near future because of a large earthquake hasn’t been observed for the instrumental period. The spatial variations in ten different seismogenic regions are estimated in NAFZ. In accordance with estimates, b-values are changed between 0.52±0.07 and 0.86±0.13. The high b values are estimated the Southern Branch of NAFZ (Edremit Fault Zones, Yenice-Gönen, Mustafa Kemal Paşa, Ulubat Faults) region, so it is related low stress. The low b values are estimated between Tokat-Erzincan region, so it is related high stress. The maps of 2D and 3D spatial variations (2D contour maps, classed post maps (a group the data into discrete classes), image maps (raster maps based on grid files), 3D wireframe (three-dimensional representations of grid files) and 3D surface) are plotted to the b-values. The spatial variations b-values can be used earthquake hazard analysis for NAFZ.

  17. On variation of word frequencies in Russian literary texts

    Science.gov (United States)

    Kargin, Vladislav

    2016-03-01

    We study the variation of word frequencies in Russian literary texts. Our findings indicate that the standard deviation of a word's frequency across texts depends on its average frequency according to a power law with exponent 1/2 volatility (that is, higher "burstiness"). A latent factor model has been estimated to investigate the structure of the word frequency distribution. The findings suggest that the dependence of a word's frequency volatility on its average frequency can be explained by the asymmetry in the distribution of latent factors.

  18. Time-Frequency, Bi-Frequency Detection Analysis of Noise Technology Radar

    National Research Council Canada - National Science Library

    Heuschel, Eugene R

    2006-01-01

    .... This thesis examines the use of time-frequency, bi-frequency signal detection techniques to identify the parameters of the four types of continuous waveform noise radar recently reported. These include: (a) random noise, (b...

  19. High frequency oscillations and infraslow activity in epilepsy

    Directory of Open Access Journals (Sweden)

    Pradeep N Modur

    2014-01-01

    Full Text Available In pre-surgical evaluation of epilepsy, there has been an increased interest in the study of electroencephalogram (EEG activity outside the 1-70 Hz band of conventional frequency activity (CFA. Research over the last couple of decades has shown that EEG activity in the 70-600 Hz range, termed high frequency oscillations (HFOs, can be recorded intracranially from all brain regions both interictally and at seizure onset. In patients with epilepsy, HFOs are now considered as pathologic regardless of their frequency band although it may be difficult to distinguish them from the physiologic HFOs, which occur in a similar frequency range. Interictal HFOs are likely to be confined mostly to the seizure onset zone, thus providing a new measure for localizing it. More importantly, several studies have linked HFOs to underlying epileptogenicity, suggesting that HFOs can serve as potential biomarkers for the illness. Along with HFOs, analysis of ictal baseline shifts (IBS; or direct current shifts and infraslow activity (ISA (ISA: <0.1 Hz has also attracted attention. Studies have shown that: IBSs can be recorded using the routine AC amplifiers with long time constants; IBSs occur at the time of conventional EEG onset, but in a restricted spatial distribution compared with conventional frequencies; and inclusion of IBS contacts in the resection can be associated with favorable seizure outcome. Only a handful of studies have evaluated all the EEG frequencies together in the same patient group. The latter studies suggest that the seizure onset is best localized by the ictal HFOs, the IBSs tend to provide a broader localization and the conventional frequencies could be non-localizing. However, small number of patients included in these studies precludes definitive conclusions regarding post-operative seizure outcome based on selective or combined resection of HFO, IBS and CFA contacts. Large, preferably prospective, studies are needed to further evaluate the

  20. High frequency oscillations and infraslow activity in epilepsy.

    Science.gov (United States)

    Modur, Pradeep N

    2014-03-01

    In pre-surgical evaluation of epilepsy, there has been an increased interest in the study of electroencephalogram (EEG) activity outside the 1-70 Hz band of conventional frequency activity (CFA). Research over the last couple of decades has shown that EEG activity in the 70-600 Hz range, termed high frequency oscillations (HFOs), can be recorded intracranially from all brain regions both interictally and at seizure onset. In patients with epilepsy, HFOs are now considered as pathologic regardless of their frequency band although it may be difficult to distinguish them from the physiologic HFOs, which occur in a similar frequency range. Interictal HFOs are likely to be confined mostly to the seizure onset zone, thus providing a new measure for localizing it. More importantly, several studies have linked HFOs to underlying epileptogenicity, suggesting that HFOs can serve as potential biomarkers for the illness. Along with HFOs, analysis of ictal baseline shifts (IBS; or direct current shifts) and infraslow activity (ISA) (ISA: AC amplifiers with long time constants; IBSs occur at the time of conventional EEG onset, but in a restricted spatial distribution compared with conventional frequencies; and inclusion of IBS contacts in the resection can be associated with favorable seizure outcome. Only a handful of studies have evaluated all the EEG frequencies together in the same patient group. The latter studies suggest that the seizure onset is best localized by the ictal HFOs, the IBSs tend to provide a broader localization and the conventional frequencies could be non-localizing. However, small number of patients included in these studies precludes definitive conclusions regarding post-operative seizure outcome based on selective or combined resection of HFO, IBS and CFA contacts. Large, preferably prospective, studies are needed to further evaluate the implications of different EEG frequencies in epilepsy.

  1. Frequency dependence of sonophoresis.

    Science.gov (United States)

    Tezel, A; Sens, A; Tuchscherer, J; Mitragotri, S

    2001-12-01

    Application of low-frequency ultrasound has been shown to increase skin permeability, thereby facilitating delivery of macromolecules (low-frequency sonophoresis). In this study, we sought to determine the dependence of low-frequency sonophoresis on ultrasound frequency, intensity and energy density. Pig skin was exposed to low-frequency ultrasound over a range of ultrasound frequency and intensity conditions. The degree of skin permeabilization was measured using its conductivity. Imaging experiments were also carried out to visualize the transport pathways created by ultrasound. The data showed that for each frequency (in the range of 19.6-93.4 kHz), there exists a threshold intensity below which no detectable conductivity enhancement was observed. The threshold intensity increased with frequency. It is feasible to achieve the desired conductivity (permeability) enhancement regardless of the choice of frequency, although the necessary energy density is higher at higher frequencies. Low frequencies (approximately 20 kHz) induced localized transport compared to a more dispersed effect seen with higher frequencies (approximately 58.9 kHz). This study provides a quantitative understanding of the effects of low-frequency ultrasound on skin permeability.

  2. Lunch frequency among adolescents

    DEFF Research Database (Denmark)

    Pedersen, Trine Pagh; Holstein, Bjørn E; Krølner, Rikke

    2016-01-01

    OBJECTIVE: To investigate: (i) how lunch frequency of adolescents varies between schools and between classes within schools; (ii) the associations between frequency of lunch and individual sociodemographic factors and school characteristics; and (iii) if any observed associations between lunch...

  3. Frequency agile solar radiotelescope

    Science.gov (United States)

    Bastian, Tim S.

    2003-02-01

    The Frequency Agile Solar Radiotelescope (FASR) is a solar-dedicated, ground based, interferometric array optimized to perform broadband imaging spectroscopy from ~ 0.1-30+ GHz. It will do so with the angular, spectral, and temporal resolution required to exploit radio emission from the Sun as a diagnostic of the wide variety of astrophysical processes that occur there. FASR represents a major advance over existing radioheliographs, and is expected to remain the world's premier solar radio instrument for two decades or more after completion. FASR will be a versatile and powerful instrument, providing unique data to a broad users community. Solar, solar-terrestrial, and space physicists will exploit FASR to attack a broad science program, including problems of fundamental interest: coronal magnetography, solar flares and particle acceleration, drivers of space weather, and the thermal structure and dynamics of the solar atmosphere. A design study and implementation planning are underway. Recent progress is reviewed here.

  4. Modeling Frequency Comb Sources

    Directory of Open Access Journals (Sweden)

    Li Feng

    2016-06-01

    Full Text Available Frequency comb sources have revolutionized metrology and spectroscopy and found applications in many fields. Stable, low-cost, high-quality frequency comb sources are important to these applications. Modeling of the frequency comb sources will help the understanding of the operation mechanism and optimization of the design of such sources. In this paper,we review the theoretical models used and recent progress of the modeling of frequency comb sources.

  5. Static electromagnetic frequency changers

    CERN Document Server

    Rozhanskii, L L

    1963-01-01

    Static Electromagnetic Frequency Changers is about the theory, design, construction, and applications of static electromagnetic frequency changers, devices that used for multiplication or division of alternating current frequency. It is originally published in the Russian language. This book is organized into five chapters. The first three chapters introduce the readers to the principles of operation, the construction, and the potential applications of static electromagnetic frequency changers and to the principles of their design. The two concluding chapters use some hitherto unpublished work

  6. A Simplified Laser and Optics System for Laser-Cooled RB Fountain Frequency Standards

    National Research Council Canada - National Science Library

    Kunz, P. D; Heavner, T. P; Jefferts, S. R

    2007-01-01

    ...) atomic fountain frequency standard. This system uses DFB (Distributed Feedback) diode lasers and a frequency offset-locking scheme to generate the optical frequencies needed for laser-cooling, launching, post-cooling, and detection of Rb atoms...

  7. Eastern Frequency Response Study

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N.W.; Shao, M.; Pajic, S.; D' Aquila, R.

    2013-05-01

    This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

  8. Making Sense of Frequency.

    Science.gov (United States)

    Larsen-Freeman, Diane

    2002-01-01

    Responds to Ellis (2002), which focuses on frequency in language processing, language use, and language acquisition. Contextualizes the frequency factor in terms of the evolution of second language acquisition (SLA) research. Suggests that although relevant and important, the frequency factor requires greater definition and qualification.…

  9. (including travel dates) Proposed itinerary

    Indian Academy of Sciences (India)

    Ashok

    31 July to 22 August 2012 (including travel dates). Proposed itinerary: Arrival in Bangalore on 1 August. 1-5 August: Bangalore, Karnataka. Suggested institutions: Indian Institute of Science, Bangalore. St Johns Medical College & Hospital, Bangalore. Jawaharlal Nehru Centre, Bangalore. 6-8 August: Chennai, TN.

  10. Failure frequencies and probabilities applicable to BWR and PWR piping

    International Nuclear Information System (INIS)

    Bush, S.H.; Chockie, A.D.

    1996-03-01

    This report deals with failure probabilities and failure frequencies of nuclear plant piping and the failure frequencies of flanges and bellows. Piping failure probabilities are derived from Piping Reliability Analysis Including Seismic Events (PRAISE) computer code calculations based on fatigue and intergranular stress corrosion as failure mechanisms. Values for both failure probabilities and failure frequencies are cited from several sources to yield a better evaluation of the spread in mean and median values as well as the widths of the uncertainty bands. A general conclusion is that the numbers from WASH-1400 often used in PRAs are unduly conservative. Failure frequencies for both leaks and large breaks tend to be higher than would be calculated using the failure probabilities, primarily because the frequencies are based on a relatively small number of operating years. Also, failure probabilities are substantially lower because of the probability distributions used in PRAISE calculations. A general conclusion is that large LOCA probability values calculated using PRAISE will be quite small, on the order of less than 1E-8 per year (<1E-8/year). The values in this report should be recognized as having inherent limitations and should be considered as estimates and not absolute values. 24 refs 24 refs

  11. Failure frequencies and probabilities applicable to BWR and PWR piping

    Energy Technology Data Exchange (ETDEWEB)

    Bush, S.H. [Review and Synthesis Associates, Richland, WA (United States); Chockie, A.D. [Chockie Group International Inc., Seattle, WA (United States)

    1996-03-01

    This report deals with failure probabilities and failure frequencies of nuclear plant piping and the failure frequencies of flanges and bellows. Piping failure probabilities are derived from Piping Reliability Analysis Including Seismic Events (PRAISE) computer code calculations based on fatigue and intergranular stress corrosion as failure mechanisms. Values for both failure probabilities and failure frequencies are cited from several sources to yield a better evaluation of the spread in mean and median values as well as the widths of the uncertainty bands. A general conclusion is that the numbers from WASH-1400 often used in PRAs are unduly conservative. Failure frequencies for both leaks and large breaks tend to be higher than would be calculated using the failure probabilities, primarily because the frequencies are based on a relatively small number of operating years. Also, failure probabilities are substantially lower because of the probability distributions used in PRAISE calculations. A general conclusion is that large LOCA probability values calculated using PRAISE will be quite small, on the order of less than 1E-8 per year (<1E-8/year). The values in this report should be recognized as having inherent limitations and should be considered as estimates and not absolute values. 24 refs 24 refs.

  12. Distributed cooperative control of AC microgrids

    Science.gov (United States)

    Bidram, Ali

    In this dissertation, the comprehensive secondary control of electric power microgrids is of concern. Microgrid technical challenges are mainly realized through the hierarchical control structure, including primary, secondary, and tertiary control levels. Primary control level is locally implemented at each distributed generator (DG), while the secondary and tertiary control levels are conventionally implemented through a centralized control structure. The centralized structure requires a central controller which increases the reliability concerns by posing the single point of failure. In this dissertation, the distributed control structure using the distributed cooperative control of multi-agent systems is exploited to increase the secondary control reliability. The secondary control objectives are microgrid voltage and frequency, and distributed generators (DGs) active and reactive powers. Fully distributed control protocols are implemented through distributed communication networks. In the distributed control structure, each DG only requires its own information and the information of its neighbors on the communication network. The distributed structure obviates the requirements for a central controller and complex communication network which, in turn, improves the system reliability. Since the DG dynamics are nonlinear and non-identical, input-output feedback linearization is used to transform the nonlinear dynamics of DGs to linear dynamics. Proposed control frameworks cover the control of microgrids containing inverter-based DGs. Typical microgrid test systems are used to verify the effectiveness of the proposed control protocols.

  13. Malignant lymphomas (including myeloproliferative disorders)

    International Nuclear Information System (INIS)

    Todd, I.D.H.

    1985-01-01

    This chapter deals with the radiotherapy and cytotoxic chemotherapy of the malignant lymphomas. Included within this group are Hodgkin's disease, non-Hodgkin's lymphoma, mycosis fungoides, and chronic lymphatic leukaemia. A further section deals with the myeloproliferative disorders, including granulocytic leukaemia, polycythaemia vera, and primary thrombocythaemia. Excluded are myeloma and reticulum cell sarcoma of bone and acute leukaemia. With regard to Hodgkin's disease, the past 25 years have seen general recognition of the curative potential of radiotherapy, at least in the local stages, and, more recently, awareness of the ability to achieve long-term survival after combination chemotherapy in generalised or in recurrent disease. At the same time the importance of staging has become appreciated and the introduction of procedures such as lymphography, staging laparotomy, and computer tomography (CT) has enormously increased its reliability. Advances have not been so dramatic in the complex group of non-Hodgkins's lymphomas, but are still very real

  14. Frequency, antimicrobial susceptibility and clonal distribution of methicillin-resistant Staphylococcus pseudintermedius in canine clinical samples submitted to a veterinary diagnostic laboratory in Italy: A 3-year retrospective investigation

    DEFF Research Database (Denmark)

    Ventrella, G.; Moodley, A.; Grandolfo, E.

    2017-01-01

    In the last decade there has been a rapid global spread of methicillin-resistant Staphylococcus pseudintermedius (MRSP) clones displaying multidrug resistance in dogs. We investigated prevalence, antimicrobial susceptibility and clonal distribution of MRSP isolated from clinical canine samples...... frequently to clindamycin, ciprofloxacin and doxycycline than methicillin-susceptible isolates. Gentamicin was the only antibiotic showing good in vitro activity on all MRSP with 20 of the 21 isolates being susceptible. Results confirm a high prevalence of MRSP amongst clinical samples in Italy, revealing...

  15. Distribution switchgear

    CERN Document Server

    Stewart, Stan

    2004-01-01

    Switchgear plays a fundamental role within the power supply industry. It is required to isolate faulty equipment, divide large networks into sections for repair purposes, reconfigure networks in order to restore power supplies and control other equipment.This book begins with the general principles of the Switchgear function and leads on to discuss topics such as interruption techniques, fault level calculations, switching transients and electrical insulation; making this an invaluable reference source. Solutions to practical problems associated with Distribution Switchgear are also included.

  16. Radio Frequency Interference Mitigation

    Science.gov (United States)

    An, T.; Chen, X.; Mohan, P.; Lao, B. Q.

    2017-09-01

    The observational facilities of radio astronomy keep constant upgrades and developments to achieve better capabilities including increasing the time of the data recording and frequency resolutions, and increasing the receiving and recording bandwidth. However in contrast, only a limited spectrum resource has been allocated to radio astronomy by the International Telecommunication Union, resulting in that the radio observational instrumentations are inevitably exposed to undesirable radio frequency interference (RFI) signals which originate mainly from the terrestrial human activity and are becoming stronger with time. RFIs degrade the quality of data and even lead to invalid data. The impact of RFIs on scientific outcome becomes more and more serious. In this article, the requirement for RFI mitigation is motivated, and the RFI characteristics, mitigation techniques, and strategies are reviewed. The mitigation strategies adopted at some representative observatories, telescopes, and arrays are also introduced. The advantages and shortcomings of the four classes of RFI mitigation strategies are discussed and presented, applicable at the connected causal stages: preventive, pre-detection, pre-correlation, and post-correlation. The proper identification and flagging of RFI is the key to the reduction of data loss and improvement in data quality, and is also the ultimate goal of developing RFI mitigation technique. This can be achieved through a strategy involving a combination of the discussed techniques in stages. The recent advances in the high speed digital signal processing and high performance computing allow for performing RFI excision of the large data volumes generated from large telescopes or arrays in both real time and offline modes, aiding the proposed strategy.

  17. Cooperative Frequency Control for Autonomous AC Microgrids

    DEFF Research Database (Denmark)

    Shafiee, Qobad; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.

    2015-01-01

    is then added to primary control, compensating the frequency drop caused by the droop mechanism. The proposed controller is fully distributed, meaning that each source exchange information with only its direct neighbors through a sparse communication network. This controller has a unique feature that it does...... not require measuring the system frequency as compared to the other presented methods. An ac Microgrid with four sources is used to verify the performance of the proposed control methodology....

  18. Device including a contact detector

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to a probe for determining an electrical property of an area of a surface of a test sample, the probe is intended to be in a specific orientation relative to the test sample. The probe may comprise a supporting body defining a first surface. A plurality of cantilever...... of cantilever arms (12) contacting the surface of the test sample when performing the movement....... arms (12) may extend from the supporting body in co-planar relationship with the first surface. The plurality of cantilever arms (12) may extend substantially parallel to each other and each of the plurality of cantilever arms (12) may include an electrical conductive tip for contacting the area...

  19. LOW FREQUENCY DAMPER

    Directory of Open Access Journals (Sweden)

    Radu BOGATEANU

    2009-09-01

    Full Text Available The low frequency damper is an autonomous equipment for damping vibrations with the 1-20Hz range.Its autonomy enables the equipment to be located in various mechanical systems, without requiring special hydraulic installations.The low frequency damper was designed for damping the low frequency oscillations occurring in the circuit controls of the upgraded IAR-99 Aircraft.The low frequency damper is a novelty in the aerospace field ,with applicability in several areas as it can be built up in an appropriate range of dimensions meeting the requirements of different beneficiaries. On this line an equipment able to damp an extended frequency range was performed for damping oscillations in the pipes of the nuclear power plants.This damper, tested in INCAS laboratories matched the requirements of the beneficiary.The low frequency damper is patented – the patent no. 114583C1/2000 is held by INCAS.

  20. Frequency Response Analysis Tool

    Energy Technology Data Exchange (ETDEWEB)

    Etingov, Pavel V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kosterev, Dmitry [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dai, T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-01

    Frequency response has received a lot of attention in recent years at the national level, which culminated in the development and approval of North American Electricity Reliability Corporation (NERC) BAL-003-1 Frequency Response and Frequency Bias Setting Reliability Standard. This report is prepared to describe the details of the work conducted by Pacific Northwest National Laboratory (PNNL) in collaboration with the Bonneville Power Administration and Western Electricity Coordinating Council (WECC) Joint Synchronized Information Subcommittee (JSIS) to develop a frequency response analysis tool (FRAT). The document provides the details on the methodology and main features of the FRAT. The tool manages the database of under-frequency events and calculates the frequency response baseline. Frequency response calculations are consistent with frequency response measure (FRM) in NERC BAL-003-1 for an interconnection and balancing authority. The FRAT can use both phasor measurement unit (PMU) data, where available, and supervisory control and data acquisition (SCADA) data. The tool is also capable of automatically generating NERC Frequency Response Survey (FRS) forms required by BAL-003-1 Standard.

  1. Nonlinear Frequency Compression

    Science.gov (United States)

    Scollie, Susan; Glista, Danielle; Seelisch, Andreas

    2013-01-01

    Frequency lowering technologies offer an alternative amplification solution for severe to profound high frequency hearing losses. While frequency lowering technologies may improve audibility of high frequency sounds, the very nature of this processing can affect the perceived sound quality. This article reports the results from two studies that investigated the impact of a nonlinear frequency compression (NFC) algorithm on perceived sound quality. In the first study, the cutoff frequency and compression ratio parameters of the NFC algorithm were varied, and their effect on the speech quality was measured subjectively with 12 normal hearing adults, 12 normal hearing children, 13 hearing impaired adults, and 9 hearing impaired children. In the second study, 12 normal hearing and 8 hearing impaired adult listeners rated the quality of speech in quiet, speech in noise, and music after processing with a different set of NFC parameters. Results showed that the cutoff frequency parameter had more impact on sound quality ratings than the compression ratio, and that the hearing impaired adults were more tolerant to increased frequency compression than normal hearing adults. No statistically significant differences were found in the sound quality ratings of speech-in-noise and music stimuli processed through various NFC settings by hearing impaired listeners. These findings suggest that there may be an acceptable range of NFC settings for hearing impaired individuals where sound quality is not adversely affected. These results may assist an Audiologist in clinical NFC hearing aid fittings for achieving a balance between high frequency audibility and sound quality. PMID:23539261

  2. Frequency Selective Reflector Antenna

    Data.gov (United States)

    National Aeronautics and Space Administration — Frequency Selective Surfaces (FSS) are an electromagnetic structure where a relatively thin, periodic, conductive material is designed as a spatial filter of...

  3. The Shape of Things to Come: Estimating Northern-Hemisphere (NH) Transient Climate Response Through Hindcasting and Forecasting the Frequency Distribution of Earth's NH Land Temperature Anomalies for the Period 1951-2071

    Science.gov (United States)

    Leclerc, D. F.

    2016-12-01

    Northern-hemisphere (NH) heatwaves, during which temperatures rise 5 standard deviations (SD), sigma, above the historical mean temperature, mu, are becoming frequent; these events skew temperature anomaly (delta T) profiles towards extreme values. Although general extreme value (GEV) distributions have modeled precipitation data, their application to temperatures have met with limited success. This work presents a modified three-parameter (mu, sigma and tau (skew)) Exponential-Gaussian (eGd) model that hindcasts decadal NH land winter (DJF) and summer (JJA) delta Ts from 1951 to 2011, and forecasts profiles for a business-as-usual (BAU) scenario for 2061-2071. We accessed 12 numerical binned (0.05 °C/bin) z-scored NH decadal datasets (posted online until August 2015) from the publicly available website http://www.columbia.edu/ mhs119/PerceptionsAndDice/ mentioned in Hansen et al, PNAS 109 E2415-E2423 (2012) and stated to be in the public domain. No pre-processing was done. Parameters were calculated for the 12 NH datasets pasted into Microsoft Excel™ through the method of moments for 1-tail distributions and through the BEST deconvolution program described by Pommé and Marroyo, Applied Radiation and Isotopes 96 148-153 (2015) for 2-tail distributions. We used maximum likelihood estimation (MLE), residual sum of squares (RSS) and F-test to find optimal parameter values. Calculated 1st (= sigma + tau) and 2nd (= sigma2 + tau2) moments were found to be within 0.5% of observed values. Land delta Ts were recovered from the z-score values by multiplying the winter data by its SD (1.2 °C) and likewise the summer data by 0.6 °C. Results were all within 0.05 °C of 10-year averages from the GHCNv3 NH land dataset. Assuming BAU (increases from 2.1 to 2.6 ppm/y CO2) and using temperature rises of 0.27 °C and 0.35 °C per decade, for summer and winter, respectively, and forecasting to 2071, we obtain for the transient climate response for doubled CO2 (560 ppm CO2) mean

  4. Optimization of a Virtual Power Plant to Provide Frequency Support.

    Energy Technology Data Exchange (ETDEWEB)

    Neely, Jason C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gonzalez, Sigifredo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lave, Matthew Samuel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Delhotal, Jarod James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    Increasing the penetration of distributed renewable sources, including photovoltaic (PV) sources, poses technical challenges for grid management. The grid has been optimized over decades to rely upon large centralized power plants with well-established feedback controls, but now non-dispatchable, renewable sources are displacing these controllable generators. This one-year study was funded by the Department of Energy (DOE) SunShot program and is intended to better utilize those variable resources by providing electric utilities with the tools to implement frequency regulation and primary frequency reserves using aggregated renewable resources, known as a virtual power plant. The goal is to eventually enable the integration of 100s of Gigawatts into US power systems.

  5. Modified Dual Second-order Generalized Integrator FLL for Frequency Estimation Under Various Grid Abnormalities

    Directory of Open Access Journals (Sweden)

    Kalpeshkumar Rohitbhai Patil

    2016-10-01

    Full Text Available Proper synchronization of Distributed Generator with grid and its performance in grid-connected mode relies on fast and precise estimation of phase and amplitude of the fundamental component of grid voltage. However, the accuracy with which the frequency is estimated is dependent on the type of grid voltage abnormalities and structure of the phase-locked loop or frequency locked loop control schemes. Among various control schemes, second-order generalized integrator based frequency- locked loop (SOGI-FLL is reported to have the most promising performance. It tracks the frequency of grid voltage accurately even when grid voltage is characterized by sag, swell, harmonics, imbalance, frequency variations etc. However, estimated frequency contains low frequency oscillations in case when sensed grid-voltage has a dc offset. This paper presents a modified dual second-order generalized integrator frequency-locked loop (MDSOGI-FLL for three-phase systems to cope with the non-ideal three-phase grid voltages having all type of abnormalities including the dc offset. The complexity in control scheme is almost the same as the standard dual SOGI-FLL, but the performance is enhanced. Simulation results show that the proposed MDSOGI-FLL is effective under all abnormal grid voltage conditions. The results are validated experimentally to justify the superior performance of MDSOGI-FLL under adverse conditions.

  6. Multielectron effects in the photoelectron momentum distribution of noble-gas atoms driven by visible-to-infrared-frequency laser pulses: A time-dependent density-functional-theory approach

    Science.gov (United States)

    Murakami, Mitsuko; Zhang, G. P.; Chu, Shih-I.

    2017-05-01

    We present the photoelectron momentum distributions (PMDs) of helium, neon, and argon atoms driven by a linearly polarized, visible (527-nm) or near-infrared (800-nm) laser pulse (20 optical cycles in duration) based on the time-dependent density-functional theory (TDDFT) under the local-density approximation with a self-interaction correction. A set of time-dependent Kohn-Sham equations for all electrons in an atom is numerically solved using the generalized pseudospectral method. An effect of the electron-electron interaction driven by a visible laser field is not recognizable in the helium and neon PMDs except for a reduction of the overall photoelectron yield, but there is a clear difference between the PMDs of an argon atom calculated with the frozen-core approximation and TDDFT, indicating an interference of its M -shell wave functions during the ionization. Furthermore, we find that the PMDs of degenerate p states are well separated in intensity when driven by a near-infrared laser field, so that the single-active-electron approximation can be adopted safely.

  7. [Measures of occupational exposure to time-varying low frequency magnetic fields of non-uniform spatial distribution in the light of international guidelines and electrodynamic exposure effects in the human body].

    Science.gov (United States)

    Karpowicz, Jolanta; Zradziński, Patryk; Gryz, Krzysztof

    2012-01-01

    The aim of study was to analyze by computer simulations the electrodynamic effects of magnetic field (MF) on workers, to harmonize the principles of occupational hazards assessment with international guidelines. Simulations involved 50 Hz MF of various spatial distributions, representing workers' exposure in enterprises. Homogeneous models of sigma = 0.2 S/m conductivity and dimensions of body parts - palm, head and trunk - were located at 50 cm ("hand-distance") or 5 cm (adjacent) from the source (circle conductor of 20 cm or 200 cm in diameter). Parameters of magnetic flux density (B(i)) affecting the models were the exposure measures, and the induced electric field strength (E(in)) was the measure of MF exposure effects. The ratio E(in)/B(i) in the analyzed cases ranged from 2.59 to 479 (V/m)/T. The strongest correlation (p assessing the effects of non-uniform fields exposure, resulting from a strong dependence of the E(in)/B(i) ratio on the conditions of exposure and its applied measures, requires special caution when defining the permissible MF levels and the principles of exposure assessment at workplace.

  8. Regional flood frequency analysis in the KwaZulu-Natal province, South Africa, using the index-flood method

    DEFF Research Database (Denmark)

    Kjeldsen, Thomas Rødding; Smithers, J.C.; Schulze, R.E.

    2002-01-01

    area was divided into two homogeneous regions based on an index of monthly rainfall concentration. Region 1 covers the coastal and midlands area and Region 2 the west north-western parts of the study area. The General Normal, Pearson Type 3 and General Pareto distributions were found to be suitable......A regional frequency analysis of annual maximum series (AMS) of flood flows from relatively unregulated rivers in the KwaZulu-Natal province of South Africa has been conducted, including identification of homogeneous regions and suitable regional frequency distributions for the regions. The study...... for AMS of flood flows in Region 2. The occurrence of a few flood events of extreme magnitude in Region 1 resulted in no suitable regional frequency distribution for this region. (C) 2002 Elsevier Science B.V. All rights reserved....

  9. “Everybody Brush!”: Protocol for a Parallel-Group Randomized Controlled Trial of a Family-Focused Primary Prevention Program With Distribution of Oral Hygiene Products and Education to Increase Frequency of Toothbrushing

    Science.gov (United States)

    2015-01-01

    Background Twice daily toothbrushing with fluoridated toothpaste is the most widely advocated preventive strategy for dental caries (tooth decay) and is recommended by professional dental associations. Not all parents, children, or adolescents follow this recommendation. This protocol describes the methods for the implementation and evaluation of a quality improvement health promotion program. Objective The objective of the study is to show a theory-informed, evidence-based program to improve twice daily toothbrushing and oral health-related quality of life that may reduce dental caries, dental treatment need, and costs. Methods The design is a parallel-group, pragmatic randomized controlled trial. Families of Medicaid-insured children and adolescents within a large dental care organization in central Oregon will participate in the trial (n=21,743). Families will be assigned to one of three groups: a test intervention, an active control, or a passive control condition. The intervention aims to address barriers and support for twice-daily toothbrushing. Families in the test condition will receive toothpaste and toothbrushes by mail for all family members every three months. In addition, they will receive education and social support to encourage toothbrushing via postcards, recorded telephone messages, and an optional participant-initiated telephone helpline. Families in the active control condition will receive the kit of supplies by mail, but no additional instructional information or telephone support. Families assigned to the passive control will be on a waiting list. The primary outcomes are restorative dental care received and, only for children younger than 36 months old at baseline, the frequency of twice-daily toothbrushing. Data will be collected through dental claims records and, for children younger than 36 months old at baseline, parent interviews and clinical exams. Results Enrollment of participants and baseline interviews have been completed. Final

  10. Frequency Mapping for the Operational Frequency Manager

    Science.gov (United States)

    2008-03-01

    and stationary computers. 1990s Late in the decade, Virtual Private Networks ( VPNs ) based on the Layer 2 Tunneling Protocol (L2TP) and IPSEC ...L2TP – Layer Two Tunnel Protocol LBNL – Lawrence Berkeley National Lab MHZ – Megahertz MIO – Maritime Interdiction Operations NOC – Network...Vehicle UHF – Ultra-High Frequency VPN – Virtual Private Network xvii ACKNOWLEDGMENTS First and foremost, we would like to thank our spouses Fatima

  11. Fast fundamental frequency estimation

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Jensen, Tobias Lindstrøm; Jensen, Jesper Rindom

    2017-01-01

    Modelling signals as being periodic is common in many applications. Such periodic signals can be represented by a weighted sum of sinusoids with frequencies being an integer multiple of the fundamental frequency. Due to its widespread use, numerous methods have been proposed to estimate the funda...

  12. Single frequency intracavity SRO

    DEFF Research Database (Denmark)

    Abitan, Haim; Buchhave, Preben

    2000-01-01

    Summary form only given. A single resonance optical parametric oscillator (SRO) is inserted intracavity to a CW high power, single frequency, and ring Nd:YVO4 laser. We obtain a stable single frequency CW SRO with output at 1.7-1.9 μm (idler) and a resonating signal at 2.3-2.6 μm. The behavior...

  13. Radar network communication through sensing of frequency hopping

    Science.gov (United States)

    Dowla, Farid; Nekoogar, Faranak

    2013-05-28

    In one embodiment, a radar communication system includes a plurality of radars having a communication range and being capable of operating at a sensing frequency and a reporting frequency, wherein the reporting frequency is different than the sensing frequency, each radar is adapted for operating at the sensing frequency until an event is detected, each radar in the plurality of radars has an identification/location frequency for reporting information different from the sensing frequency, a first radar of the radars which senses the event sends a reporting frequency corresponding to its identification/location frequency when the event is detected, and all other radars in the plurality of radars switch their reporting frequencies to match the reporting frequency of the first radar upon detecting the reporting frequency switch of a radar within the communication range. In another embodiment, a method is presented for communicating information in a radar system.

  14. Microfabricated ion frequency standard

    Science.gov (United States)

    Schwindt, Peter; Biedermann, Grant; Blain, Matthew G.; Stick, Daniel L.; Serkland, Darwin K.; Olsson, III, Roy H.

    2010-12-28

    A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.

  15. The continuous wave NQR spectrometer with equidistant frequency scale

    Directory of Open Access Journals (Sweden)

    Samila A. P.

    2010-10-01

    Full Text Available The phase binding frequency of marginal oscillator to frequency synthesizer which includes a phase detector, are used for linearization of the frequency sweep. For spectrum calibration the circuit is designed which forms «scale rule» of the frequency tags with an interval of 10 and 100 kHz.

  16. Frequency Effects in Second Language Acquisition: An Annotated Survey

    Science.gov (United States)

    Kartal, Galip; Sarigul, Ece

    2017-01-01

    The aim of this study is to investigate the relationship between frequency and language acquisition from many perspectives including implicit and explicit instruction, frequency effects on morpheme acquisition in L2, the relationship between frequency and multi-word constructions, frequency effects on phonetics, vocabulary, gerund and infinitive…

  17. Multivariate Frequency-Severity Regression Models in Insurance

    Directory of Open Access Journals (Sweden)

    Edward W. Frees

    2016-02-01

    Full Text Available In insurance and related industries including healthcare, it is common to have several outcome measures that the analyst wishes to understand using explanatory variables. For example, in automobile insurance, an accident may result in payments for damage to one’s own vehicle, damage to another party’s vehicle, or personal injury. It is also common to be interested in the frequency of accidents in addition to the severity of the claim amounts. This paper synthesizes and extends the literature on multivariate frequency-severity regression modeling with a focus on insurance industry applications. Regression models for understanding the distribution of each outcome continue to be developed yet there now exists a solid body of literature for the marginal outcomes. This paper contributes to this body of literature by focusing on the use of a copula for modeling the dependence among these outcomes; a major advantage of this tool is that it preserves the body of work established for marginal models. We illustrate this approach using data from the Wisconsin Local Government Property Insurance Fund. This fund offers insurance protection for (i property; (ii motor vehicle; and (iii contractors’ equipment claims. In addition to several claim types and frequency-severity components, outcomes can be further categorized by time and space, requiring complex dependency modeling. We find significant dependencies for these data; specifically, we find that dependencies among lines are stronger than the dependencies between the frequency and average severity within each line.

  18. Breakfast frequency among adolescents

    DEFF Research Database (Denmark)

    Pedersen, Trine Pagh; Holstein, Bjørn E; Damsgaard, Mogens Trab

    2016-01-01

    OBJECTIVE: To investigate (i) associations between adolescents' frequency of breakfast and family functioning (close relations to parents, quality of family communication and family support) and (ii) if any observed associations between breakfast frequency and family functioning vary by sociodemo......OBJECTIVE: To investigate (i) associations between adolescents' frequency of breakfast and family functioning (close relations to parents, quality of family communication and family support) and (ii) if any observed associations between breakfast frequency and family functioning vary...... by sociodemographic factors. DESIGN: School-based cross-sectional study. Students completed a web-based questionnaire. Associations were estimated by multilevel multivariate logistic regression. SETTING: Danish arm of the Health Behaviour in School-aged Children study, 2014. SUBJECTS: Adolescents aged 13 and 15 years...... (n 3054) from a random sample of forty-one schools. RESULTS: Nearly one-quarter of the adolescents had low breakfast frequency. Low breakfast frequency was associated with low family functioning measured by three dimensions. The OR (95 % CI) of low breakfast frequency was 1·81 (1·40, 2...

  19. Frequency comb swept lasers.

    Science.gov (United States)

    Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C; Fujimoto, James G

    2009-11-09

    We demonstrate a frequency comb (FC) swept laser and a frequency comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range frequency comb filter in the swept lasers causes the lasers to generate a series of well defined frequency steps. The narrow bandwidth (0.015nm) of the frequency comb filter enables a approximately -1.2dB sensitivity roll off over approximately 3mm range, compared to conventional swept source and FDML lasers which have -10dB and -5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0-3mm appear aliased back into the principal range. In addition, the frequency comb output from the lasers are equally spaced in frequency (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier transformation of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed.

  20. Low-frequency sonophoresis: a review.

    Science.gov (United States)

    Mitragotri, Samir; Kost, Joseph

    2004-03-27

    Application of ultrasound enhances skin permeability to a variety of molecules (sonophoresis). The enhancement induced by ultrasound is particularly significant at low-frequencies (fsonophoresis). This review summarizes mechanisms and applications of low-frequency sonophoresis. In vitro, in vivo, as well as clinical studies demonstrating the effect of low-frequency ultrasound on transdermal drug delivery and glucose extraction are summarized. Mechanistic insights gained through a number of investigations are also reviewed. Finally, reports on the synergistic effect of low-frequency ultrasound with other enhancers including chemicals and iontophoresis are summarized.