High Selectivity Dual-Band Bandpass Filter with Tunable Lower Passband

Directory of Open Access Journals (Sweden)

Wei-Qiang Pan

2015-01-01

Full Text Available This paper presents a novel method to design dual-band bandpass filters with tunable lower passband and fixed upper passband. It utilizes a trimode resonator with three controllable resonant modes. Discriminating coupling is used to suppress the unwanted mode to avoid the interference. Varactors are utilized to realize tunable responses. The bandwidth of the two bands can be controlled individually. Transmission zeros are generated near the passband edges, resulting in high selectivity. For demonstration, a tunable bandpass filter is implemented. Good agreement between the prediction and measurement validates the proposed method.

Spectral design of temperature-invariant narrow bandpass filters for the mid-infrared

DEFF Research Database (Denmark)

Stolberg-Rohr, Thomine Kirstine; Hawkins, Gary J.

2015-01-01

The ability of narrow bandpass filters to discriminatewavelengths between closely-separated gas absorption lines is crucial inmany areas of infrared spectroscopy. As improvements to the sensitivity ofinfrared detectors enables operation in uncontrolled high-temperature environments, this imposes ...... presents the results of an investigation into the interdependence between multilayer bandpass designand optical materials together with a review on invariance at elevated temperatures....

Dual and tri-band bandpass filters based on novel Π-shaped resonator

Science.gov (United States)

Xiao, Jian-Kang; Zhu, Wen-Jun; Zhao, Wei

2014-05-01

A novel Π-shaped resonator is proposed, and compact dual-band and tri-band bandpass filters that meet IEEE 802.11 application requirements by using the new resonator are designed. The dual-band bandpass filter centres at 2.45 and 5.6 GHz with a simulated passband insertion loss of no more than 0.8 dB, and the tri-band bandpass filter which is got by two-path coupling achieves simulated passband insertion loss of no more than 1.1 dB. The new designs are demonstrated by experiment. The new filters have advantages of simple and compact structures, low passband insertion losses, good frequency selectivity and miniature circuit sizes. All these have prospect to be applied in future wireless communication systems.

A novel 2nd-order bandpass MFSS filter with miniaturized structure

Directory of Open Access Journals (Sweden)

C. Y. Fang

2015-08-01

Full Text Available In order to effectively obtain a miniaturized structure and good filtering properties, we propose a novel 2nd-order bandpass metamaterial frequency selective surface (MFSS filter which contains two capacitive layers and one inductive layer, where there are multi-loop metallic patches as shunt capacitor C and planar wire grids as series inductor L respectively. Unlike the traditional operation way—the tuned elements used in resonant surface approximately equal to one wavelength in circumference and the structure thickness with a spacing of a quarter wavelength apart, by changing the value of L and C and matching multilayer dielectric to adjust the LC coupling resonance and the resonance impedance respectively, the proposed MFSS filter can achieves a miniatured structure with ideal bandpass properties. Measurement results of the fabricated prototype of the bandpass filter (BPF indicate that the dimension of the tuned element on resonant surface is approximately 0.025 wavelength, i.e., 0.025λ. At the same time, the filter has the stable center frequency of f0 = 1.53GHz and the transmittance of T ⩾ 96.3% and high Q-value for the TE/TM wave polarization at various incidence angles. The novel 2nd-order bandpass MFSS filter with miniaturized structure not only can decrease structure dimension, but also has a wide range of applications to microwave and infrared band.

Microstrip Cross-coupled Interdigital SIR Based Bandpass Filter

Directory of Open Access Journals (Sweden)

R. K. Maharjan

2012-09-01

Full Text Available A simple and compact 4.9 GHz bandpass filter for C-band applications is proposed. This paper presents a novel microstrip cross-coupled interdigital half-wavelength stepped impedance resonator (SIR based bandpass filter (BPF.The designed structure is similar to that of a combination of two parallel interdigital capacitors. The scattering parameters of the structure are measured using vector network analyzer (VNA. The self generated capacitive and inductive reactances within the interdigital resonators exhibited in a resonance frequency of 4.9 GHz. The resonant frequency and bandwidth of the capacitive cross-coupled resonator is directly optimized from the physical arrangement of the resonators. The measured insertion loss (S21 and return loss (S11 were 0.3 dB and 28 dB, respectively, at resonance frequency which were almost close to the simulation results.

Tracking the business cycle of the Euro area: A multivariate model-based band-pass filter

NARCIS (Netherlands)

Azevedo, J.M.; Koopman, S.J.; Rua, A.

2006-01-01

This article proposes a multivariate bandpass filter based on the trend plus cycle decomposition model. The underlying multivariate dynamic factor model relies on specific formulations for trend and cycle components and produces smooth business cycle indicators with bandpass filter properties.

A 65mW,0.4-2.3 GHz bandpass filter for satellite receivers

NARCIS (Netherlands)

Tang, van der J.D.; Kasperkovitz, D.; Bretveld, A.

2002-01-01

A monolithic tunable bandpass filter for satellite receiver front-ends is presented. The nter frequency of the bandpass filter can be tuned from 0.4 GHz to 2.3 GHz. The filter is constructed using four transconductor-C poly-phase filter sections and has a 50 dB variable gain range. At 20 dB

Fabrication of Compact Microstrip Line-Based Balun-Bandpass Filter with High Common-Mode Suppression

Directory of Open Access Journals (Sweden)

Chia-Mao Chen

2014-01-01

Full Text Available A new type of balun-bandpass filter was proposed based on the traditional coupled-line theory and folded open-loop ring resonators (OLRRs configuration. For that, a new device with both filter-type and balun-type characteristics was investigated and fabricated. Both magnetic and electric coupling structures were implemented to provide high performance balun-bandpass responses. The fabricated balun-bandpass filters had a wide bandwidth more than 200 MHz and a low insertion loss less than 2.51 dB at a center frequency of 2.6 GHz. The differences between the two outputs were below 0.4 dB in magnitude and within 180 ± 7° in phase. Also, the balun-bandpass filter presented an excellent common-mode rejection ratio over 25 dB in the passband. An advanced design methodology had been adopted based on EM simulation for making these designed parameters of OLRRs, microstrip lines, and open stubs. The measured frequency responses agreed well with simulated ones.

Plasmonic Band-Pass Microfilters for LWIR Absorption Spectroscopy

Directory of Open Access Journals (Sweden)

J. M. Banks

2012-01-01

Full Text Available Absorption spectroscopy in the long wave infrared provides an effective method for identification of various hazardous chemicals. We present a theoretical design for plasmonic band-pass filters that can be used to provide wavelength selectivity for uncooled microbolometer sensors. The microfilters consist of a pair of input reflection gratings that couple light into a plasmonic waveguide with a central resonant waveguide cavity. An output transmission grating on the other side of the structure pulls light out of the waveguide where it is detected by a closely spaced sensor. Fabrication of the filters can be performed using standard photolithography procedures. A spectral bandpass with a full-width at half-maximum (FWHM of 100 nm can be obtained with a center wavelength spanning the entire 8–12 μm atmospheric transmission window by simple geometric scaling of only the lateral dimensions. This allows the simultaneous fabrication of all the wavelength filters needed for a full spectrometer on a chip.

Tunable bandpass filter based on photonic crystal fiber filled with multiple liquid crystals

DEFF Research Database (Denmark)

Scolari, Lara; Tartarini, G.; Borelli, E.

2007-01-01

A tunable bandpass filter based on a photonic crystal fiber filled with two different liquid crystals is demonstrated. 130 nm bandwidth tunability is achieved by tuning the temperature from 30degC to 90degC.......A tunable bandpass filter based on a photonic crystal fiber filled with two different liquid crystals is demonstrated. 130 nm bandwidth tunability is achieved by tuning the temperature from 30degC to 90degC....

Noise-Coupled Image Rejection Architecture of Complex Bandpass ΔΣAD Modulator

Science.gov (United States)

San, Hao; Kobayashi, Haruo

This paper proposes a new realization technique of image rejection function by noise-coupling architecture, which is used for a complex bandpass ΔΣAD modulator. The complex bandpass ΔΣAD modulator processes just input I and Q signals, not image signals, and the AD conversion can be realized with low power dissipation. It realizes an asymmetric noise-shaped spectra, which is desirable for such low-IF receiver applications. However, the performance of the complex bandpass ΔΣAD modulator suffers from the mismatch between internal analog I and Q paths. I/Q path mismatch causes an image signal, and the quantization noise of the mirror image band aliases into the desired signal band, which degrades the SQNDR (Signal to Quantization Noise and Distortion Ratio) of the modulator. In our proposed modulator architecture, an extra notch for image rejection is realized by noise-coupled topology. We just add some passive capacitors and switches to the modulator; the additional integrator circuit composed of an operational amplifier in the conventional image rejection realization is not necessary. Therefore, the performance of the complex modulator can be effectively raised without additional power dissipation. We have performed simulation with MATLAB to confirm the validity of the proposed architecture. The simulation results show that the proposed architecture can achieve the realization of image-rejection effectively, and improve the SQNDR of the complex bandpass ΔΣAD modulator.

Optimization of band-pass filtering parameters of a Raman lidar detecting atmospheric water vapor

International Nuclear Information System (INIS)

Cao, Kai-Fa; Hu, Shun-Xing; Wang, Ying-jian

2012-01-01

It is very important for daytime Raman lidar measurement of water vapor to determine the parameters of a band-pass filter, which are pertinent to the lidar signal to noise ratio (SNR). The simulated annealing (SA) algorithm method has an advantage in finding the extremum of a certain cost function. In this paper, the Raman spectrum of water vapor is simulated and then a first realization of a simulated annealing algorithm in the optimization of a band-pass filter of a Raman lidar system designed to detect daytime water vapor is presented. The simulated results indicate that the narrow band-pass filter has higher SNR than the wide filter does but there would be an increase in the temperature sensitivity of a narrowband Raman water vapor lidar in the upper troposphere. The numerical simulation indicates that the magnitude of the temperature dependent effect can reach 3.5% or more for narrow band-pass Raman water vapor measurements so it is necessary to consider a new water vapor Raman lidar equation that permits the temperature sensitivity of these equations to be confined to a single term. (paper)

Spectral and Wavefront Error Performance of WFIRST-AFTA Bandpass Filter Coating Prototypes

Science.gov (United States)

Quijada, Manuel A.; Seide, Laurie; Pasquale, Bert A.; McMann, Joseph C.; Hagopian, John G.; Dominguez, Margaret Z.; Gong, Quian; Marx, Catherine T.

2016-01-01

The Cycle 5 design baseline for the Wide-Field Infrared Survey Telescope Astrophysics Focused Telescope Assets (WFIRST/AFTA) instrument includes a single wide-field channel (WFC) instrument for both imaging and slit-less spectroscopy. The only routinely moving part during scientific observations for this wide-field channel is the element wheel (EW) assembly. This filter-wheel assembly will have 8 positions that will be populated with 6 bandpass filters, a blank position, and a Grism that will consist of a three-element assembly to disperse the full field with an undeviated central wavelength for galaxy redshift surveys. All filter elements in the EW assembly will be made out of fused silica substrates (110 mm diameter) that will have the appropriate bandpass coatings according to the filter designations (Z087, Y106, J129, H158, F184, W149 and Grism). This paper presents and discusses the performance (including spectral transmission and reflected/transmitted wavefront error measurements) of a subset of bandpass filter coating prototypes that are based on the WFC instrument filter compliment. The bandpass coating prototypes that are tested in this effort correspond to the Z087, W149, and Grism filter elements. These filter coatings have been procured from three different vendors to assess the most challenging aspects in terms of the in-band throughput, out of band rejection (including the cut-on and cutoff slopes), and the impact the wavefront error distortions of these filter coatings will have on the imaging performance of the wide-field channel in the WFIRST/AFTA observatory.

Determination of uranium in environmental samples from the Nile delta and the adjacent regions of Egypt using laser fluorimetry

Energy Technology Data Exchange (ETDEWEB)

Shawky, S; Ibrahim, N; Farouk, A [National research Center for Nuclear safety and radiation Control, Atomic Energy Authority, cairo (Egypt); Ghods, A [IAEA Laboratories, Chemistry Unit., A 244 Seibersdorf, (Austria)

1995-10-01

Total uranium content was determined in soil and plant samples taken from various areas in the Nile delta. Samples from east and west of the delta, the suez canal` cities and from alexandria region were analyzed using laser fluorimetry (LF). Uranium was extracted from digested ashed samples with methyl-isobutyl ketone (MIBK) and measured using laser fluorimeter. The radium content of the same soil samples was determined using gamma spectrometry (GS). The uranium content of plant samples was determined using (LF), since it has a detection limit lower than of (GS). The uranium content varied between 0.6-4.4{mu}g/g and 0.032-0.17 {mu}g/g for soil and plant samples respectively. 1 fig., 3 tabs.

Determination of uranium in environmental samples from the Nile delta and the adjacent regions of Egypt using laser fluorimetry

International Nuclear Information System (INIS)

Shawky, S.; Ibrahim, N.; Farouk, A.; Ghods, A.

1995-01-01

Total uranium content was determined in soil and plant samples taken from various areas in the Nile delta. Samples from east and west of the delta, the suez canal' cities and from alexandria region were analyzed using laser fluorimetry (LF). Uranium was extracted from digested ashed samples with methyl-isobutyl ketone (MIBK) and measured using laser fluorimeter. The radium content of the same soil samples was determined using gamma spectrometry (GS). The uranium content of plant samples was determined using (LF), since it has a detection limit lower than of (GS). The uranium content varied between 0.6-4.4μg/g and 0.032-0.17 μg/g for soil and plant samples respectively. 1 fig., 3 tabs

UWB Bandpass Filter with Ultra-wide Stopband based on Ring Resonator

Science.gov (United States)

Kazemi, Maryam; Lotfi, Saeedeh; Siahkamari, Hesam; Mohammadpanah, Mahmood

2018-04-01

An ultra-wideband (UWB) bandpass filter with ultra-wide stopband based on a rectangular ring resonator is presented. The filter is designed for the operational frequency band from 4.10 GHz to 10.80 GHz with an ultra-wide stopband from 11.23 GHz to 40 GHz. The even and odd equivalent circuits are used to achieve a suitable analysis of the proposed filter performance. To verify the design and analysis, the proposed bandpass filter is simulated using full-wave EM simulator Advanced Design System and fabricated on a 20mil thick Rogers_RO4003 substrate with relative permittivity of 3.38 and a loss tangent of 0.0021. The proposed filter behavior is investigated and simulation results are in good agreement with measurement results.

A Miniaturize Bandpass Filter with Harmonic Suppression Using Meandered Quarter-Wavelength Resonators

Directory of Open Access Journals (Sweden)

Yun-Long Lu

2014-01-01

Full Text Available A miniaturized bandpass filter with harmonics suppression is presented. The proposed filter consists of two quarter-wavelength microstrip resonators, which are meandered for circuit size reduction. An interdigital capacitor, loading at zero-voltage point, is employed to provide the desired coupling between the resonators at operating frequency, whereas the coupling coefficient at the third harmonic is realized to be zero. Besides, the second and fourth harmonics are suppressed since λ/4 resonators are adopted. Benefiting from these properties, a miniaturized bandpass filter with the second, third, and fourth harmonics suppression was designed and implemented. The final measured and simulated results show good consistence with the theoretical counterparts.

Homogeneous samples of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}

Energy Technology Data Exchange (ETDEWEB)

Hoogenboom, B.W.; Kadowaki, K.; Revaz, B.; Fischer, O

2003-09-15

Recently, much attention has been paid to inhomogeneity in samples of the high-temperature superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}. In this work it is shown that homogeneous samples can indeed be obtained in the slightly overdoped range. However, the homogeneity critically depends on sample preparation.

Design of doubly focusing, tunable (5 to 30 keV), wide-bandpass optics made from layered synthetic microstructures

International Nuclear Information System (INIS)

Bilderback, D.H.; Lairson, B.M.; Barbee, T.W. Jr.; Ice, G.E.; Sparks, C.J. Jr.

1982-01-01

Layered Synthetic Microstructures (LSMs) show great promise as focusing, high-throughput, hard x-ray monochromators. Experimental reflectivity vs. energy curves have been obtained on carbon-tungsten and carbon-molybdenum LSMs of up to 260 layers in thickness. Reflectivities for three flat LSMs with different bandpasses were 70% with δE/E = 5.4%, 66% with δE/E = 1.4%, and 19% with δE/E = 0.6%. A new generation of variable bandwidth optics using two successive LSMs is proposed. The first element will be an LSM deposited on a substrate that can be water cooled as it intercepts direct radiation from a storage ring. It can be bent for vertical focusing. The bandpass can be adjusted by choosing interchangeable first elements from an assortment of LSM's with different bandpasses (for example, δE/E = 0.005, 0.01, 0.02, 0.05, 0.1). The second LSM will consist of a multilayered structure with a 10% bandpass built onto a flexible substrate that can be bent for sagittal focusing. The result will be double focusing optics with an adjustable energy bandpass that are tunable from 5 to 30 keV

A Compact Band-Pass Filter with High Selectivity and Second Harmonic Suppression.

Science.gov (United States)

Hadarig, Ramona Cosmina; de Cos Gomez, Maria Elena; Las-Heras, Fernando

2013-12-03

The design of a novel band-pass filter with narrow-band features based on an electromagnetic resonator at 6.4 GHz is presented. A prototype is manufactured and characterized in terms of transmission and reflection coefficient. The selective passband and suppression of the second harmonic make the filter suitable to be used in a C band frequency range for radar systems and satellite/terrestrial applications. To avoid substantial interference for this kind of applications, passive components with narrow band features and small dimensions are required. Between 3.6 GHz and 4.2 GHz the band-pass filter with harmonic suppression should have an attenuation of at least 35 dB, whereas for a passband, less than 10% is sufficient.

Optical Interference Coatings Design Contest 2007: triple bandpass filter and nonpolarizing beam splitter.

Science.gov (United States)

Tilsch, Markus; Hendrix, Karen

2008-05-01

A triple bandpass filter (28 solutions received) and a nonpolarizing beam splitter (23 solutions received) were the subjects of the design contest held in conjunction with the 2007 Optical Interference Coatings topical meeting of the Optical Society of America. Fifteen designers participated using a wide spectrum of design approaches and optimization strategies to create the submissions. The results differ significantly, but all meet the contest requirements. Fabien Lemarchand wins both contests by submitting the thinnest (6254 nm) triple bandpass design and the widest (61.7 nm) nonpolarizing beam-splitter design. Michael Trubetskov is in second place, followed by Vladimir Pervak in both contests. The submitted designs are described and evaluated.

Neural Model for Left-Handed CPW Bandpass Filter Loaded Split Ring Resonator

Science.gov (United States)

Liu, Haiwen; Wang, Shuxin; Tan, Mingtao; Zhang, Qijun

2010-02-01

Compact left-handed coplanar waveguide (CPW) bandpass filter loaded split ring resonator (SRR) is presented in this paper. The proposed filter exhibits a quasi-elliptic function response and its circuit size occupies only 12 × 11.8 mm2 (≈0.21 λg × 0.20 λg). Also, a simple circuit model is given and the parametric study of this filter is discussed. Then, with the aid of NeuroModeler software, a five-layer feed-forward perceptron neural networks model is built up to optimize the proposed filter design fast and accurately. Finally, this newly left-handed CPW bandpass filter was fabricated and measured. A good agreement between simulations and measurement verifies the proposed left-handed filter and the validity of design methodology.

Fourier transform profilometry (FTP) using an innovative band-pass filter for accurate 3-D surface reconstruction

Science.gov (United States)

Chen, Liang-Chia; Ho, Hsuan-Wei; Nguyen, Xuan-Loc

2010-02-01

This article presents a novel band-pass filter for Fourier transform profilometry (FTP) for accurate 3-D surface reconstruction. FTP can be employed to obtain 3-D surface profiles by one-shot images to achieve high-speed measurement. However, its measurement accuracy has been significantly influenced by the spectrum filtering process required to extract the phase information representing various surface heights. Using the commonly applied 2-D Hanning filter, the measurement errors could be up to 5-10% of the overall measuring height and it is unacceptable to various industrial application. To resolve this issue, the article proposes an elliptical band-pass filter for extracting the spectral region possessing essential phase information for reconstructing accurate 3-D surface profiles. The elliptical band-pass filter was developed and optimized to reconstruct 3-D surface models with improved measurement accuracy. Some experimental results verify that the accuracy can be effectively enhanced by using the elliptical filter. The accuracy improvement of 44.1% and 30.4% can be achieved in 3-D and sphericity measurement, respectively, when the elliptical filter replaces the traditional filter as the band-pass filtering method. Employing the developed method, the maximum measured error can be kept within 3.3% of the overall measuring range.

Retinal blood vessel extraction using tunable bandpass filter and fuzzy conditional entropy.

Science.gov (United States)

Sil Kar, Sudeshna; Maity, Santi P

2016-09-01

Extraction of blood vessels on retinal images plays a significant role for screening of different opthalmologic diseases. However, accurate extraction of the entire and individual type of vessel silhouette from the noisy images with poorly illuminated background is a complicated task. To this aim, an integrated system design platform is suggested in this work for vessel extraction using a sequential bandpass filter followed by fuzzy conditional entropy maximization on matched filter response. At first noise is eliminated from the image under consideration through curvelet based denoising. To include the fine details and the relatively less thick vessel structures, the image is passed through a bank of sequential bandpass filter structure optimized for contrast enhancement. Fuzzy conditional entropy on matched filter response is then maximized to find the set of multiple optimal thresholds to extract the different types of vessel silhouettes from the background. Differential Evolution algorithm is used to determine the optimal gain in bandpass filter and the combination of the fuzzy parameters. Using the multiple thresholds, retinal image is classified as the thick, the medium and the thin vessels including neovascularization. Performance evaluated on different publicly available retinal image databases shows that the proposed method is very efficient in identifying the diverse types of vessels. Proposed method is also efficient in extracting the abnormal and the thin blood vessels in pathological retinal images. The average values of true positive rate, false positive rate and accuracy offered by the method is 76.32%, 1.99% and 96.28%, respectively for the DRIVE database and 72.82%, 2.6% and 96.16%, respectively for the STARE database. Simulation results demonstrate that the proposed method outperforms the existing methods in detecting the various types of vessels and the neovascularization structures. The combination of curvelet transform and tunable bandpass

Application of HTSC-thin films in microwave bandpass filters

International Nuclear Information System (INIS)

Jha, A.R.

1993-01-01

This paper reveals unique performance capabilities of High-Temperature Superconducting Thin-Film (HTSCTFs) for possible applications in microwave bandpass filters (BPFs). Microwave filters fabricated with HTSCTFs have demonstrated lowest insertion loss, highest rejection, and sharpest skirt selectivity. Thin films of Yttrium Barium Copper Oxide (YBCO), Bismuth Strontium Calcium Copper Oxide (BSCCO) and Thallium Calcium Barium Copper Oxide (TCBCO) will be most attractive for filters

The acetone bandpass detector for inverse photoemission: operation in proportional and Geiger–Müller modes

Science.gov (United States)

Thiede, Christian; Niehues, Iris; Schmidt, Anke B.; Donath, Markus

2018-06-01

Inverse photoemission is the most versatile experimental tool to study the unoccupied electronic structure at surfaces of solids. Typically, the experiments are performed in the isochromat mode with bandpass photon detectors. For gas-filled counters, the bandpass behavior is realized by the combination of the photoionization threshold of the counting gas as the high-pass filter and the ultraviolet transmission cutoff of an alkaline earth fluoride entrance window as the low-pass filter. The transmission characteristics of the entrance window determine the optical bandpass. The performance of the counter depends on the composition of the detection gas and the fill-gas pressure, the readout electronics and the counter geometry. For the well-known combination of acetone and CaF2, the detector can be operated in proportional and Geiger–Müller modes. In this work, we review aspects concerning the working principles, the counter construction and the read-out electronics. We identify optimum working parameters and provide a step-by-step recipe how to build, install and operate the device.

Band-pass filtering algorithms for adaptive control of compressor pre-stall modes in aircraft gas-turbine engine

Science.gov (United States)

Kuznetsova, T. A.

2018-05-01

The methods for increasing gas-turbine aircraft engines' (GTE) adaptive properties to interference based on empowerment of automatic control systems (ACS) are analyzed. The flow pulsation in suction and a discharge line of the compressor, which may cause the stall, are considered as the interference. The algorithmic solution to the problem of GTE pre-stall modes’ control adapted to stability boundary is proposed. The aim of the study is to develop the band-pass filtering algorithms to provide the detection functions of the compressor pre-stall modes for ACS GTE. The characteristic feature of pre-stall effect is the increase of pressure pulsation amplitude over the impeller at the multiples of the rotor’ frequencies. The used method is based on a band-pass filter combining low-pass and high-pass digital filters. The impulse response of the high-pass filter is determined through a known low-pass filter impulse response by spectral inversion. The resulting transfer function of the second order band-pass filter (BPF) corresponds to a stable system. The two circuit implementations of BPF are synthesized. Designed band-pass filtering algorithms were tested in MATLAB environment. Comparative analysis of amplitude-frequency response of proposed implementation allows choosing the BPF scheme providing the best quality of filtration. The BPF reaction to the periodic sinusoidal signal, simulating the experimentally obtained pressure pulsation function in the pre-stall mode, was considered. The results of model experiment demonstrated the effectiveness of applying band-pass filtering algorithms as part of ACS to identify the pre-stall mode of the compressor for detection of pressure fluctuations’ peaks, characterizing the compressor’s approach to the stability boundary.

Multiple plasmonically induced transparency for chip-scale bandpass filters in metallic nanowaveguides

Science.gov (United States)

Lu, Hua; Yue, Zengqi; Zhao, Jianlin

2018-05-01

We propose and investigate a new kind of bandpass filters based on the plasmonically induced transparency (PIT) effect in a special metal-insulator-metal (MIM) waveguide system. The finite element method (FEM) simulations illustrate that the obvious PIT response can be generated in the metallic nanostructure with the stub and coupled cavities. The lineshape and position of the PIT peak are particularly dependent on the lengths of the stub and coupled cavities, the waveguide width, as well as the coupling distance between the stub and coupled cavities. The numerical simulations are in accordance with the results obtained by the temporal coupled-mode theory. The multi-peak PIT effect can be achieved by integrating multiple coupled cavities into the plasmonic waveguide. This PIT response contributes to the flexible realization of chip-scale multi-channel bandpass filters, which could find crucial applications in highly integrated optical circuits for signal processing.

All-optical OFDM demultiplexing by spectral magnification and optical band-pass filtering

DEFF Research Database (Denmark)

Palushani, Evarist; Mulvad, Hans Christian Hansen; Kong, Deming

2013-01-01

We propose spectral magnification of optical-OFDM super-channels using time-lenses, enabling reduced inter-carrier-interference in subcarrier detection by simple band-pass filtering. A demonstration on an emulated 100 Gbit/s DPSK optical-OFDM channel shows improved sensitivities after 4-times spe...

Sampling frequency affects ActiGraph activity counts

DEFF Research Database (Denmark)

Brønd, Jan Christian; Arvidsson, Daniel

that is normally performed at frequencies higher than 2.5 Hz. With the ActiGraph model GT3X one has the option to select sample frequency from 30 to 100 Hz. This study investigated the effect of the sampling frequency on the ouput of the bandpass filter.Methods: A synthetic frequency sweep of 0-15 Hz was generated...... in Matlab and sampled at frequencies of 30-100 Hz. Also, acceleration signals during indoor walking and running were sampled at 30 Hz using the ActiGraph GT3X and resampled in Matlab to frequencies of 40-100 Hz. All data was processed with the ActiLife software.Results: Acceleration frequencies between 5......-15 Hz escaped the bandpass filter when sampled at 40, 50, 70, 80 and 100 Hz, while this was not the case when sampled at 30, 60 and 90 Hz. During the ambulatory activities this artifact resultet in different activity count output from the ActiLife software with different sampling frequency...

Highly Tunable Narrow Bandpass MEMS Filter

KAUST Repository

Hafiz, Md Abdullah Al

2017-07-07

We demonstrate a proof-of-concept highly tunable narrow bandpass filter based on electrothermally and electrostatically actuated microelectromechanical-system (MEMS) resonators. The device consists of two mechanically uncoupled clamped-clamped arch resonators, designed such that their resonance frequencies are independently tuned to obtain the desired narrow passband. Through the electrothermal and electrostatic actuation, the stiffness of the structures is highly tunable. We experimentally demonstrate significant percentage tuning (~125%) of the filter center frequency by varying the applied electrothermal voltages to the resonating structures, while maintaining a narrow passband of 550 ± 50 Hz, a stopband rejection of >17 dB, and a passband ripple ≤ 2.5 dB. An analytical model based on the Euler-Bernoulli beam theory is used to confirm the behavior of the filter, and the origin of the high tunability using electrothermal actuation is discussed.

Design of 2.5 GHz broad bandwidth microwave bandpass filter at operating frequency of 10 GHz using HFSS

Science.gov (United States)

Jasim, S. E.; Jusoh, M. A.; Mahmud, S. N. S.; Zamani, A. H.

2018-04-01

Development of low losses, small size and broad bandwidth microwave bandpass filter operating at higher frequencies is an active area of research. This paper presents a new route used to design and simulate microwave bandpass filter using finite element modelling and realized broad bandwidth, low losses, small dimension microwave bandpass filter operating at 10 GHz frequency using return loss method. The filter circuit has been carried out using Computer Aid Design (CAD), Ansoft HFSS software and designed with four parallel couple line model and small dimension (10 × 10 mm2) using LaAlO3 substrate. The response of the microwave filter circuit showed high return loss -50 dB at operating frequency at 10.4 GHz and broad bandwidth of 2.5 GHz from 9.5 to 12 GHz. The results indicate the filter design and simulation using HFSS is reliable and have the opportunity to transfer from lab potential experiments to the industry.

A Differential 4-Path Highly Linear Widely Tunable On-Chip Band-Pass Filter

NARCIS (Netherlands)

Ghaffari, A.; Klumperink, Eric A.M.; Nauta, Bram

2010-01-01

Abstract A passive switched capacitor RF band-pass filter with clock controlled center frequency is realized in 65nm CMOS. An off-chip transformer which acts as a balun, improves filter-Q and realizes impedance matching. The differential architecture reduces clock-leakage and suppresses selectivity

Assessment of heavy metal concentrations in water, sediment and biota (fish and crabs) samples from the Densu Delta

International Nuclear Information System (INIS)

Kudu, I.B.

2010-01-01

The aim of the study was assess the concentration of some selected heavy metals in water, sediments and biota (fish and crab) sampled from the Densu Delta. In situ and laboratory based analysis were carried out to measure the following physicochemical properties of surface water from the delta; temperature, pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), alkalinity, sodium ion concentration (Na+), potassium ion concentration (K+), chloride ion concentration (Cl), bicarbonate concentration, phosphate concentration, nitrate concentration, sulphate concentration and biochemical oxygen demand (BOD). Heavy metal (Fe, Zn, Cu, Ni, Cd, Cr, Pb and Hg) concentrations in water, sediments, fish and crab sampled at six sites from the Densu Delta wetland in the month of December, 2009 were analysed using VARIAN Fast Sequential Atomic Absorption Spectrophotometer (AAS) model AA240 FS. Two fish species; Blackchin tilapia (Sarotherodon melanotheron), White mullet (Mugil curema) and one species of crab; Blue swimming crab (Callinectes amnicola) were collected from the Densu Delta wetland and analysed. Heavy metal contents in the fish were higher in gill tissue than muscle tissue while in crabs concentrations were higher in the soft tissue than the shell. Levels of Fe, Zn and Cu in the muscle tissue of S. melanotheron were greater than the levels detected in the muscle tissue of M. curema. Cd, Ni and Hg were detected in gill tissue but not in the muscle tissue of S. melanotheron, M. curema on the other hand contained these metals in both gill and muscle tissue. The maximum level of Fe (34.98 mg/L), Zn (25.08 mg/L) in the muscle of S. melanotheron was observed at Bortianor and Zn (2.70 mg/L) was observed at Tetegu. In the M. curema, the maximum level of Fe (34.66 mg/L), Zn (15.9 mg/L) and Cu (1.43 mg/L) was detected at Aplaku, Tetegu and Faana respectively. Heavy metal concentrations were higher in sediment than water. The presence of elevated levels of Cd

A Microwave Tunable Bandpass Filter for Liquid Crystal Applications

Science.gov (United States)

Cao, Weiping; Jiang, Di; Liu, Yupeng; Yang, Yuanwang; Gan, Baichuan

2017-07-01

In this paper, a novel microwave continuously tunable band-pass filter, based on nematic liquid crystals (LCs), is proposed. It uses liquid crystal (LC) as the electro-optic material to mainly realize frequency shift at microwave band by changing the dielectric anisotropy, when applying the bias voltage. According to simulation results, it achieves 840 MHz offset. Comparing to the existing tunable filter, it has many advantages, such as continuously tunable, miniaturization, low processing costs, low tuning voltage, etc. Thus, it has shown great potentials in frequency domain and practical applications in modern communication.

Miniaturized and Ferrite Based Tunable Bandpass Filters in LCP and LTCC Technologies for SoP Applications

KAUST Repository

Arabi, Eyad A.

2015-04-01

Wireless systems with emerging applications are leaning towards small size, light-weight and low cost. Another trend for these wireless devices is that new applications and functionalities are being added without increasing the size of the device. To accomplish this, individual components must be miniaturized and the system should be designed to maximize the integration of the individual components. The high level of 3D integration feasible in system on package design (SoP) concept can fulfill the latter requirement. Bandpass filters are important components on all wireless systems to reject the unwanted signals and reduce interference. Being mostly implemented with passive and distributed components, bandpass filters take considerable space in a wireless system. Moreover, with emerging bands and multiple applications encompassed in a single device, many bandpass filters are required. The miniaturization related to bandpass filters can be approached by three main ways: (1) at the component level through the miniaturization of individual bandpass filters, (2) at the system level through the use of tunable filters to reduce the overall number of filters, and (3) at the system level through the high level of integration in a 3D SoP platform. In this work we have focused on all three aspects of miniaturization of band pass filters mentioned above. In the first part of this work, a low frequency (1.5 GHz global positioning system (GPS) band) filter implemented through 3D lumped components in two leading SoP technologies, namely low temperature co-fired ceramic (LTCC) and the liquid crystal polymers (LCP) is demonstrated. The miniaturized filter is based on a second order topology, which has been modified to improve the selectivity and out-of-band rejection without increasing the size. Moreover, for the case of LCP, the filter is realized in an ultra-thin stack up comprising four metallization layers with an overall thickness of only 100 _m. Due to its ultra

Abraham Reef Stable Isotope Data (delta 13C, delta 18O, delta 14C) for 1635-1957

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Site: Abraham Reef, 22ó 06'S, 153ó 00'E, Porites australiensus, Radiocarbon (delta 14C) and Stable Isotope (del 18O and del 13C) results from bi-annual samples from...

Unexpected {delta}{sup 18}O and {delta}{sup 2}H Variability of Groundwater in the Eastern Paris Basin

Energy Technology Data Exchange (ETDEWEB)

Gourcy, L.; Petelet-Giraud, E. [BRGM Service EAU, Orleans (France)

2013-07-15

The Paris Basin covers about one-third of the total surface area of France. In 2009, two campaigns sampling 25 boreholes tapping Tertiary aquifers were carried out in the Basin. These aquifers are recharged at a similar altitude and the groundwater age is too young to have registered climate change. In the past, regional studies included the use of isotopes to understand groundwater origin and dynamics. Both {delta}{sup 18}O and {delta}{sup 2}H as well as ages (CFC/SF{sub 6)} and chemical components were determined in all collected samples. A noticeable stable isotope 'anomaly' appears in the south-western part of the Basin, where the average {delta}{sup 18}O and {delta}{sup 2}H values are more depleted and do not fit the pattern given by the continental effect in this area. A regional particularity of the spatial distribution of such isotopes in precipitation may be possible, but should be confirmed by additional work. (author)

Tunable high-channel-count bandpass plasmonic filters based on an analogue of electromagnetically induced transparency

International Nuclear Information System (INIS)

Lu Hua; Liu Xueming; Wang Guoxi; Mao Dong

2012-01-01

We have proposed a novel type of bandpass plasmonic filter consisting of metal–insulator–metal bus waveguides coupled with a series of side-coupled cavities and stub waveguides. The theoretical modeling demonstrates that our waveguide-resonator system performs a plasmonic analogue of electromagnetically induced transparency (EIT) in atomic systems, as is confirmed by numerical experiments. The plasmonic EIT-like response enables the realization of nanoscale bandpass filters with multiple channels. Additionally, the operating wavelengths and bandwidths of our filters can be efficiently tuned by adjusting the geometric parameters such as the lengths of stub waveguides and the coupling distances between the cavities and stub waveguides. The ultracompact configurations contribute to the achievement of wavelength division multiplexing systems for optical computing and communications in highly integrated optical circuits. (paper)

DELTAS: A new Global Delta Sustainability Initiative (Invited)

Science.gov (United States)

Foufoula-Georgiou, E.

2013-12-01

Deltas are economic and environmental hotspots, food baskets for many nations, home to a large part of the world population, and hosts of exceptional biodiversity and rich ecosystems. Deltas, being at the land-water interface, are international, regional, and local transport hubs, thus providing the basis for intense economic activities. Yet, deltas are deteriorating at an alarming rate as 'victims' of human actions (e.g. water and sediment reduction due to upstream basin development), climatic impacts (e.g. sea level rise and flooding from rivers and intense tropical storms), and local exploration (e.g. sand or aggregates, groundwater and hydrocarbon extraction). Although many efforts exist on individual deltas around the world, a comprehensive global delta sustainability initiative that promotes awareness, science integration, data and knowledge sharing, and development of decision support tools for an effective dialogue between scientists, managers and policy makers is lacking. Recently, the international scientific community proposed to establish the International Year of Deltas (IYD) to serve as the beginning of such a Global Delta Sustainability Initiative. The IYD was proposed as a year to: (1) increase awareness and attention to the value and vulnerability of deltas worldwide; (2) promote and enhance international and regional cooperation at the scientific, policy, and stakeholder level; and (3) serve as a launching pad for a 10-year committed effort to understand deltas as complex socio-ecological systems and ensure preparedness in protecting and restoring them in a rapidly changing environment. In this talk, the vision for such an international coordinated effort on delta sustainability will be presented as developed by a large number of international experts and recently funded through the Belmont Forum International Opportunities Fund. Participating countries include: U.S., France, Germany, U.K., India, Japan, Netherlands, Norway, Brazil, Bangladesh

Optimal updating magnitude in adaptive flat-distribution sampling.

Science.gov (United States)

Zhang, Cheng; Drake, Justin A; Ma, Jianpeng; Pettitt, B Montgomery

2017-11-07

We present a study on the optimization of the updating magnitude for a class of free energy methods based on flat-distribution sampling, including the Wang-Landau (WL) algorithm and metadynamics. These methods rely on adaptive construction of a bias potential that offsets the potential of mean force by histogram-based updates. The convergence of the bias potential can be improved by decreasing the updating magnitude with an optimal schedule. We show that while the asymptotically optimal schedule for the single-bin updating scheme (commonly used in the WL algorithm) is given by the known inverse-time formula, that for the Gaussian updating scheme (commonly used in metadynamics) is often more complex. We further show that the single-bin updating scheme is optimal for very long simulations, and it can be generalized to a class of bandpass updating schemes that are similarly optimal. These bandpass updating schemes target only a few long-range distribution modes and their optimal schedule is also given by the inverse-time formula. Constructed from orthogonal polynomials, the bandpass updating schemes generalize the WL and Langfeld-Lucini-Rago algorithms as an automatic parameter tuning scheme for umbrella sampling.

Dependence of {delta}E effect on internal stresses in nickel: Experimental results by laser interferometry

Energy Technology Data Exchange (ETDEWEB)

Chicharro, J.M. [Dept. de Mecanica Aplicada e Ingenieria de Proyectos, E.T.S.I. Industriales, Universidad de Castilla-La Mancha, Avd. Camilo Jose Cela s/n, 13071 Ciudad Real (Spain)]. E-mail: josemanuel.chicharro@uclm.es; Bayon, A. [Dept. de Fisica Aplicada a los Recursos Naturales, E.T.S.I. Minas, Universidad Politecnica de Madrid, c/Rios Rosas, 21, 28003 Madrid (Spain); Salazar, F. [Dept. de Fisica Aplicada a los Recursos Naturales, E.T.S.I. Minas, Universidad Politecnica de Madrid, c/Rios Rosas, 21, 28003 Madrid (Spain)

2006-02-15

The speckle heterodyne interferometry is applied to the study of the dependence of Young's modulus on both the magnetic field and the internal stresses in a soft ferromagnetic material. Young's modulus is determined from the first natural longitudinal frequency of a slender magnetic rod positioned within a solenoid. Vibration of the sample is detected by an optical heterodyne system with a wide bandwidth. The samples are heated to above the Curie point and then cooled at several rates in order to induce different internal stresses. The study refers to nickel rods 10mm in diameter and 110mm in length. The grain sizes of the samples are also determined and related to changes in {delta}E.

Average of delta: a new quality control tool for clinical laboratories.

Science.gov (United States)

Jones, Graham R D

2016-01-01

Average of normals is a tool used to control assay performance using the average of a series of results from patients' samples. Delta checking is a process of identifying errors in individual patient results by reviewing the difference from previous results of the same patient. This paper introduces a novel alternate approach, average of delta, which combines these concepts to use the average of a number of sequential delta values to identify changes in assay performance. Models for average of delta and average of normals were developed in a spreadsheet application. The model assessed the expected scatter of average of delta and average of normals functions and the effect of assay bias for different values of analytical imprecision and within- and between-subject biological variation and the number of samples included in the calculations. The final assessment was the number of patients' samples required to identify an added bias with 90% certainty. The model demonstrated that with larger numbers of delta values, the average of delta function was tighter (lower coefficient of variation). The optimal number of samples for bias detection with average of delta was likely to be between 5 and 20 for most settings and that average of delta outperformed average of normals when the within-subject biological variation was small relative to the between-subject variation. Average of delta provides a possible additional assay quality control tool which theoretical modelling predicts may be more valuable than average of normals for analytes where the group biological variation is wide compared with within-subject variation and where there is a high rate of repeat testing in the laboratory patient population. © The Author(s) 2015.

All-optical OFDM demultiplexing by spectral magnification and band-pass filtering.

Science.gov (United States)

Palushani, E; Mulvad, H C Hansen; Kong, D; Guan, P; Galili, M; Oxenløwe, L K

2014-01-13

We propose a simple OFDM receiver allowing for the use of standard WDM receivers to receive spectrally advanced OFDM signals. We propose to spectrally magnify the optical-OFDM super-channels using a spectral telescope consisting of two time-lenses, which enables reduced inter-carrier-interference in subcarrier detection by simple band-pass filtering. A demonstration on an emulated 100 Gbit/s DPSK optical-OFDM channel shows improved sensitivities after 4-times spectral magnification.

Effects of recharge and discharge on delta2H and delta18O composition and chloride concentration of high arsenic/fluoride groundwater from the Datong Basin, northern China.

Science.gov (United States)

Xie, Xianjun; Wang, Yanxin; Su, Chunli; Duan, Mengyu

2013-02-01

To better understand the effects of recharge and discharge on the hydrogeochemistry of high levels of arsenic (As) and fluoride (F) in groundwater, environmental isotopic composition (delta2H and delta18O) and chloride (Cl) concentrations were analyzed in 29 groundwater samples collected from the Datong Basin. High arsenic groundwater samples (As > 50 micog/L) were found to be enriched in lighter isotopic composition that ranged from -92 to -78 per thousand for deuterium (delta2H) and from -12.5 to -9.9 per thousand for oxygen-18 (delta18O). High F-containing groundwater (F > 1 mg/L) was relatively enriched in heavier isotopic composition and varied from -90 to -57 per thousand and from -12.2 to -6.7 per thousand for delta2H and delta18O, respectively. High chloride concentrations and delta18O values were primarily measured in groundwater samples from the northern and southwestern portions of the study area, indicating the effect of evaporation on groundwater. The observation of relatively homogenized and low delta18O values and chloride concentrations in groundwater samples from central part of the Datong Basin might be a result of fast recharge by irrigation returns, which suggests that irrigation using arsenic-contaminated groundwater affected the occurrence of high arsenic-containing groundwater in the basin.

Reduced size dual band pass filters for RFID applications with excellent bandpass/bandstop characteristics

Science.gov (United States)

Abdalla, M. A.; Choudhary, D. Kumar; Chaudhary, R. Kumar

2018-02-01

This paper presents the design of two reduced size dual-band metamaterial bandpass filters and its simulation followed by measurements of proposed filters. These filters are supporting different frequency bands and primarily could be utilize in radio frequency identification (RFID) application. The filter includes three cells in which two are symmetrical and both inductively coupled with the third cell which is present in between them. In the proposed designs, three different metamaterial composite right/left handed (CRLH) cell resonators have been analysed for compactness. The CRLH cell consists of an interdigital capacitor, a stub/meander line/spiral inductor and a via to connect the top of the structure and ground plane. Finally, the proposed dual band bandpass filters (using meander line and spiral inductor) are showing size reduction by 65% and 50% (with 25% operating frequency reduction), respectively, in comparison with reference filter using stub inductor. More than 30 dB attenuation has been achieved between the two passbands.

Piecewise spectrally band-pass for compressive coded aperture spectral imaging

International Nuclear Information System (INIS)

Qian Lu-Lu; Lü Qun-Bo; Huang Min; Xiang Li-Bin

2015-01-01

Coded aperture snapshot spectral imaging (CASSI) has been discussed in recent years. It has the remarkable advantages of high optical throughput, snapshot imaging, etc. The entire spatial-spectral data-cube can be reconstructed with just a single two-dimensional (2D) compressive sensing measurement. On the other hand, for less spectrally sparse scenes, the insufficiency of sparse sampling and aliasing in spatial-spectral images reduce the accuracy of reconstructed three-dimensional (3D) spectral cube. To solve this problem, this paper extends the improved CASSI. A band-pass filter array is mounted on the coded mask, and then the first image plane is divided into some continuous spectral sub-band areas. The entire 3D spectral cube could be captured by the relative movement between the object and the instrument. The principle analysis and imaging simulation are presented. Compared with peak signal-to-noise ratio (PSNR) and the information entropy of the reconstructed images at different numbers of spectral sub-band areas, the reconstructed 3D spectral cube reveals an observable improvement in the reconstruction fidelity, with an increase in the number of the sub-bands and a simultaneous decrease in the number of spectral channels of each sub-band. (paper)

Ultra-narrow bandpass filters for long range optical telecommunications at 1064nm and 1550nm, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Ultra-narrow bandpass filters with high off-band rejection are needed to maximize signal to noise for free space communications. Omega Optical is developing NIR...

High-Q Bandpass Comb Filter for Mains Interference Extraction

Directory of Open Access Journals (Sweden)

Neycheva T.

2009-12-01

Full Text Available This paper presents a simple digital high-Q bandpass comb filter for power-line (PL or other periodical interference extraction. The filter concept relies on a correlated signal average resulting in alternating constructive and destructive spectrum interference i.e. the so-called comb frequency response. The presented filter is evaluated by Matlab simulations with real ECG signal contaminated with low amplitude PL interference. The made simulations show that this filter accurately extract the PL interference. It has high-Q notches only at PL odd harmonics and is appropriate for extraction of any kind of odd harmonic interference including rectangular shape. The filter is suitable for real-time operation with popular low-cost microcontrollers.

Nonlinear performance characterization in an eight-pole quasi-elliptic bandpass filter

International Nuclear Information System (INIS)

Mateu, J; Collado, C; Menendez, O; O'Callaghan, J M

2004-01-01

In this work we predict the nonlinear behaviour of an eight-pole quasi-elliptic bandpass high temperature superconducting (HTS) filter with an equivalent circuit extracted from intermodulation measurements performed at the centre of the filter passband. We present measurements that show that the equivalent circuit is able to predict the intermodulation products produced by the filter when driven by two in-band or out-of-band sinusoidal signals. Numerical techniques based on harmonic balance are used to extract the elements of the equivalent circuit and to simulate its nonlinear performance

Implementation of an ESA delta-DOR capability

Science.gov (United States)

James, Nick; Abello, Ricard; Lanucara, Marco; Mercolino, Mattia; Maddè, Roberto

2009-06-01

This paper describes the implementation of delta-DOR (delta-differential one-way ranging) receivers within the ESA Deep Space ground station network. Delta-DOR provides very accurate plane-of-sky measurements of spacecraft position which complement existing line-of-sight ranging and Doppler measurements. We discuss how this technique has been adapted and implemented at the two ESA deep-space ground stations using existing equipment and infrastructure. These new capabilities were added by writing new software modules for the standard ESA digital receiver (the intermediate frequency modem system—IFMS). With these upgrades the receiver has the ability to record accurately timetagged signals from up to eight IF sub-channels. These sub-channels can have bandwidths of 50 kHz-2 MHz with a sample quantization of 1-16 bits per component. The IF samples are stored locally for subsequent retrieval over a WAN by the correlator facility at ESOC.

Highly chirped single-bandpass microwave photonic filter with reconfiguration capabilities.

Science.gov (United States)

Bolea, Mario; Mora, José; Ortega, Beatriz; Capmany, José

2011-02-28

We propose a novel photonic structure to implement a chirped single-bandpass microwave photonic filter based on the amplitude modulation of a broadband optical signal transmitted by a non-linear dispersive element and an interferometric system prior to balanced photodetection. A full reconfigurability of the filter is achieved since amplitude and phase responses can be independently controlled. We have experimentally demonstrated chirp values up to tens of ns/GHz, which is, as far as we know, one order of magnitude better than others achieved by electrical approaches and furthermore, without restrictions in terms of frequency tuning since a frequency operation range up to 40 GHz has been experimentally demonstrated.

A miniaturized Microwave Bandpass Filter Based on Modified (Mg0.95Ca0.05TiO3 Substrate

Directory of Open Access Journals (Sweden)

Hu Mingzhe

2016-01-01

Full Text Available A microwave miniaturized bandpass filter using (Mg0.95Ca0.05TiO3 (abbreviated as 95MCT hereafter ceramic substrate is investigated in the present paper. The paper studies the sintering and microwave dielectric properties of Al2O3, La2O3 and SiO2 co-doped 95MCT. The XRD pattern shows that a secondary phase MgTi2O5 is easily segregated in 95MCT ceramic, however, through co-doping it can be effectively suppressed, and the microwave dielectric properties, especially, the Qf value can be significantly improved. Through optimizing the co-doping ratio of Al2O3, La2O3 and SiO2, the sintering temperature of 95MCT ceramic can be lowered by 80°C, and the microwave dielectric properties can reach Qf=61856GHz and εr=19.84, which indicates the modified 95MCT ceramic have a great potential application in microwave communication devices. Based on this, we also designed a miniaturized microwave bandpass filter (BPF on modified 95MCT substrate. Through a full wave electromagnetic structure simulation, the results show that the center frequency of the BPF is 2.45GHz and the relative bandwidth is 4.09% with the insertion loss of less than 0.2dB in the whole bandpass.

The MACHO Project Sample of Galactic Bulge High-Amplitude {delta} Scuti Stars: Pulsation Behavior and Stellar Properties

Energy Technology Data Exchange (ETDEWEB)

Alcock, C.; Allsman, R. A.; Alves, D. R.; Axelrod, T. S.; Becker, A. C.; Bennett, D. P.; Cook, K. H.; Freeman, K. C.; Geha, M.; Griest, K. (and others)

2000-06-20

We have detected 90 objects with periods and light-curve structures similar to those of field {delta} Scuti stars using the Massive Compact Halo Object (MACHO) Project database of Galactic bulge photometry. If we assume similar extinction values for all candidates and absolute magnitudes similar to those of other field high-amplitude {delta} Scuti stars (HADS), the majority of these objects lie in or near the Galactic bulge. At least two of these objects are likely foreground {delta} Scuti stars, one of which may be an evolved nonradial pulsator, similar to other evolved, disk-population {delta} Scuti stars. We have analyzed the light curves of these objects and find that they are similar to the light curves of field {delta} Scuti stars and the {delta} Scuti stars found by the Optical Gravitational Lens Experiment (OGLE). However, the amplitude distribution of these sources lies between those of low- and high-amplitude {delta} Scuti stars, which suggests that they may be an intermediate population. We have found nine double-mode HADS with frequency ratios ranging from 0.75 to 0.79, four probable double- and multiple-mode objects, and another four objects with marginal detections of secondary modes. The low frequencies (5-14 cycles day-1) and the observed period ratios of {approx}0.77 suggest that the majority of these objects are evolved stars pulsating in fundamental or first overtone radial modes. (c) 2000 The American Astronomical Society.

Application of Cu{sub 2}O-doped phosphate glasses for bandpass filter

Energy Technology Data Exchange (ETDEWEB)

Elhaes, H. [Physics Department, Faculty of Women for Arts, Science and Education, Ain Shams University, 11757 Cairo (Egypt); Attallah, M., E-mail: m_atallah94@yahoo.com [Basic Science Department, Higher Technological Institute, 10th of Ramadan City (Egypt); Elbashar, Y.; El-Okr, M. [Physics Department, Faculty of Science, Al Azhar University, Cairo (Egypt); Ibrahim, M. [Spectroscopy Department, National Research Centre, 12311 Dokki, Cairo (Egypt)

2014-09-15

Phosphate glasses doped with copper ions having general composition 42P{sub 2}O{sub 5}–39ZnO–(18−x) Na{sub 2}O–1CaO–xCu{sub 2}O [x=2, 4, 6, 8, 10 mol%] were prepared using a conventional melt-quench technique. Physical and chemical properties of the glasses were investigated using X-ray diffraction technique and UV–visible optical absorption. The density was measured by Archimedes' method, and molar volume (V{sub M}) was calculated. It is found that density and molar volume show opposite trend by increasing Cu{sub 2}O content. Absorbance and transmittance at the normal incidence are measured by a spectrophotometer in the spectral range of 190–1100 nm. Analyses of the obtained results were considered in the frame of current theories. Absorption data were used for absorption coefficient, the optical band gap (E{sub opt}), the cutoff in UV and IR bands to the bandpass filter, which confirmed the optical properties of this type of filter. E{sub opt} values for different glass samples are found to decrease with increasing Cu{sub 2}O content.

Dense grid of narrow bandpass filters for the JST/T250 telescope: summary of results

Science.gov (United States)

Brauneck, Ulf; Sprengard, Ruediger; Bourquin, Sebastien; Marín-Franch, Antonio

2018-01-01

On the Javalambre mountain in Spain, the Centro de Estudios de Fisica del Cosmos de Aragon has setup two telescopes, the JST/T250 and the JAST/T80. The JAST/T80 telescope integrates T80Cam, a large format, single CCD camera while the JST/T250 will mount the JPCam instrument, a 1.2Gpix camera equipped with a 14-CCD mosaic using the new large format e2v 9.2k×9.2k 10-μm pixel detectors. Both T80Cam and JPCam integrate a large number of filters in dimensions of 106.8×106.8 mm2 and 101.7×95.5 mm2, respectively. For this instrument, SCHOTT manufactured 56 specially designed steep edged bandpass interference filters, which were recently completed. The filter set consists of bandpass filters in the range between 348.5 and 910 nm and a longpass filter at 915 nm. Most of the filters have full-width at half-maximum (FWHM) of 14.5 nm and a blocking between 250 and 1050 nm with optical density of OD5. Absorptive color glass substrates in combination with interference filters were used to minimize residual reflection in order to avoid ghost images. In spite of containing absorptive elements, the filters show the maximum possible transmission. This was achieved by using magnetron sputtering for the filter coating process. The most important requirement for the continuous photometric survey is the tight tolerancing of the central wavelengths and FWHM of the filters. This insures each bandpass has a defined overlap with its neighbors. A high image quality required a low transmitted wavefront error (<λ/4 locally and <λ/2 on the whole aperture), which was achieved even by combining two or three substrates. We report on the spectral and interferometric results measured on the whole set of filters.

An asymmetric MOSFET-C band-pass filter with on-chip charge pump auto-tuning

International Nuclear Information System (INIS)

Chen Fangxiong; Ma Heping; Jia Hailong; Shi Yin; Lin Min; Dai, Forster

2009-01-01

An asymmetric MOSFET-C band-pass filter (BPF) with on chip charge pump auto-tuning is presented. It is implemented in UMC (United Manufacturing Corporation) 0.18 μm CMOS process technology. The filter system with auto-tuning uses a master-slave technique for continuous tuning in which the charge pump outputs 2.663 V, much higher than the power supply voltage, to improve the linearity of the filter. The main filter with third order low-pass and second order high-pass properties is an asymmetric band-pass filter with bandwidth of 2.730-5.340 MHz. The in-band third order harmonic input intercept point (IIP3) is 16.621 dBm, with 50 Ω as the source impedance. The input referred noise is about 47.455 μV rms . The main filter dissipates 3.528 mW while the auto-tuning system dissipates 2.412 mW from a 1.8 V power supply. The filter with the auto-tuning system occupies 0.592 mm 2 and it can be utilized in GPS (global positioning system) and Bluetooth systems. (semiconductor integrated circuits)

An asymmetric MOSFET-C band-pass filter with on-chip charge pump auto-tuning

Energy Technology Data Exchange (ETDEWEB)

Chen Fangxiong; Ma Heping; Jia Hailong; Shi Yin [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Lin Min [Suzhou-CAS Semiconductors Integrated Technology Research Center, Suzhou 215021 (China); Dai, Forster, E-mail: fxchen@semi.ac.c [Department of Electrical and Computer Engineering, Auburn University, AL 36849 (United States)

2009-08-15

An asymmetric MOSFET-C band-pass filter (BPF) with on chip charge pump auto-tuning is presented. It is implemented in UMC (United Manufacturing Corporation) 0.18 {mu}m CMOS process technology. The filter system with auto-tuning uses a master-slave technique for continuous tuning in which the charge pump outputs 2.663 V, much higher than the power supply voltage, to improve the linearity of the filter. The main filter with third order low-pass and second order high-pass properties is an asymmetric band-pass filter with bandwidth of 2.730-5.340 MHz. The in-band third order harmonic input intercept point (IIP3) is 16.621 dBm, with 50 {Omega} as the source impedance. The input referred noise is about 47.455 {mu}V{sub rms}. The main filter dissipates 3.528 mW while the auto-tuning system dissipates 2.412 mW from a 1.8 V power supply. The filter with the auto-tuning system occupies 0.592 mm{sup 2} and it can be utilized in GPS (global positioning system) and Bluetooth systems. (semiconductor integrated circuits)

Influence of different organic fertilizers on quality parameters and the delta(15)N, delta(13)C, delta(2)H, delta(34)S, and delta(18)O values of orange fruit (Citrus sinensis L. Osbeck).

Science.gov (United States)

Rapisarda, Paolo; Camin, Federica; Fabroni, Simona; Perini, Matteo; Torrisi, Biagio; Intrigliolo, Francesco

2010-03-24

To investigate the influence of different types of fertilizers on quality parameters, N-containing compounds, and the delta(15)N, delta(13)C, delta(2)H, delta (34)S, and delta(18)O values of citrus fruit, a study was performed on the orange fruit cv. 'Valencia late' (Citrus sinensis L. Osbeck), which was harvested in four plots (three organic and one conventional) located on the same farm. The results demonstrated that different types of organic fertilizers containing the same amount of nitrogen did not effect important changes in orange fruit quality parameters. The levels of total N and N-containing compounds such as synephrine in fruit juice were not statistically different among the different treatments. The delta(15)N values of orange fruit grown under fertilizer derived from animal origin as well as from vegetable compost were statistically higher than those grown with mineral fertilizer. Therefore, delta(15)N values can be used as an indicator of citrus fertilization management (organic or conventional), because even when applied organic fertilizers are of different origins, the natural abundance of (15)N in organic citrus fruit remains higher than in conventional ones. These treatments also did not effect differences in the delta(13)C, delta(2)H, delta(34)S, and delta(18)O values of fruit.

Challenges, Approaches and Experiences from Asian Deltas and the Rhine-Meuse Delta : Regional Training Workshop on Delta Planning and Management

NARCIS (Netherlands)

Wosten, J.H.M.; Douven, W.; Long Phi, H.; Fida Abdullah Khan, M.

2013-01-01

River delta's, like the Mekong Delta (Vietnam), Ganges-Brahmaputra Delta (Bangladesh), Ayeyarwady Delta (Myanmar), Nile (Egypt) and Ciliwung Delta (Indonesia) are developing rapidly and are characterised by large-scale urbanisation and industrialization processes. They are facing serious planning

Analogue demonstration of a high temperature superconducting sigma-delta modulator with 27 GHz sampling

Energy Technology Data Exchange (ETDEWEB)

Forrester, M.G.; Hunt, B.D.; Miller, D.L.; Talvacchio, J.; Young, R.M. [Northrop Grumman Science and Technology Center, Pittsburgh, PA 15235-5098 (United States)

1999-11-01

We have successfully fabricated and tested a high temperature superconducting (HTS) sigma-delta modulator for analogue-to-digital conversion. This is the first demonstration of a GHz sampling A-to-D in HTS. The 15-junction single-flux-quantum (SFQ) circuit, fabricated using an epitaxial multilayer HTS process with YBCO/Co-YBCO/YBCO edge junctions, was internally clocked at 27 GHz and used to convert a 5.01 MHz signal. The modulator demonstrated a spur-free dynamic range of more than 75 dB. Two-tone measurements with 5.01 MHz and 5.51 MHz signals demonstrated third-order intermodulation products to be lower than -59 dBc. Demonstration of a functional HTS modulator represents a significant milestone in the development of high dynamic range ADCs suitable for such applications as surveillance radar. (author)

Delta Plaza kohvik = Delta Plaza cafe

Index Scriptorium Estoniae

2010-01-01

Tallinnas Pärnu mnt 141 asuva kohviku Delta Plaza sisekujundusest. Sisearhitektid Tiiu Truus ja Marja Viltrop (Stuudio Truus OÜ). Tiiu Truusi tähtsamate tööde loetelu. Büroohoone Delta Plaza arhitektid Marika Lõoke ja Jüri Okas (AB J. Okas & M. Lõoke)

Acceptability and usability of self-collected sampling for HPV testing among African-American women living in the Mississippi Delta.

Science.gov (United States)

Scarinci, Isabel C; Litton, Allison G; Garcés-Palacio, Isabel C; Partridge, Edward E; Castle, Philip E

2013-01-01

Human papillomavirus (HPV) DNA testing has been shown to be an effective approach to cervical cancer screening, and self-collection sampling for HPV testing could be a potential alternative to Pap test, provided that women who tested positive by any method get timely follow-up and care. This feasibility study examined acceptability and usability of self-collected sampling for HPV testing among African-American (AA) women in the Mississippi Delta to inform the development of interventions to promote cervical cancer screening in this population. The study consisted of two phases. Phase I consisted of eight focus groups (n = 87) with AA women to explore knowledge, attitudes, and beliefs about cervical cancer and HPV infection as well as acceptability of self-collected sampling for HPV testing. In phase II, we examined the usability of this technology through one discussion group (n = 9). The Health Belief Model guided data collection and analysis. Although participants perceived themselves as susceptible to cervical cancer and acknowledged its severity, there was a lack of knowledge of the link between HPV and cervical cancer, and they expressed a number of misconceptions. The most frequent barriers to screening included embarrassment, discomfort, and fear of the results. Women in both phases were receptive to self-collected sampling for HPV testing. All participants in the usability phase expressed that self-collection was easy and they did not experience any difficulties. Self-collection for HPV testing is an acceptable and feasible method among AA women in the Mississippi Delta to complement current cytology cervical cancer screening programs. Copyright © 2013 Jacobs Institute of Women's Health. Published by Elsevier Inc. All rights reserved.

Growth laws for sub-delta crevasses in the Mississippi River Delta

Science.gov (United States)

Yocum, T. A.; Georgiou, I. Y.; Straub, K. M.

2017-12-01

River deltas are threatened by environmental change, including subsidence, global sea level rise, reduced sediment inputs and other local factors. In the Mississippi River Delta (MRD) these impacts are exemplified, and have led to proposed solutions to build land that include sediment diversions to reinitiate the delta cycle. Deltas were studied extensively using numerical models, theoretical and conceptual frameworks, empirical scaling relationships, laboratory models and field observations. But predicting the future of deltas relies on field observations where for most deltas data are still lacking. Moreover, empirical and theoretical scaling laws may be influenced by the data used to develop them, while laboratory deltas may be influenced by scaling issues. Anthropogenic crevasses in the MRD are large enough to overcome limitations of laboratory deltas, and small enough to allow for rapid channel and wetland development, providing an ideal setting to investigate delta development mechanics. Here we assessed growth laws of sub-delta crevasses (SDC) in the MRD, in two experimental laboratory deltas (LD - weakly and strongly cohesive) and compared them to river dominated deltas worldwide. Channel and delta geometry metrics for each system were obtained using geospatial tools, bathymetric datasets, sediment size, and hydrodynamic observations. Results show that SDC follow growth laws similar to large river dominated deltas, with the exception of some that exhibit anomalous behavior with respect to the frequency and distance to a bifurcation and the fraction of wetted delta shoreline (allometry metrics). Most SDC exhibit a systematic decrease of non-dimensional channel geometries with increased bifurcation order, indicating that channels are adjusting to decreased flow after bifurcations occur, and exhibit linear trends for land allometry and width-depth ratio, although geometries decrease more rapidly per bifurcation order. Measured distance to bifurcations in SDC

Deformation characteristics of {delta} phase in the delta-processed Inconel 718 alloy

Energy Technology Data Exchange (ETDEWEB)

Zhang, H.Y., E-mail: haiyanzhang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang, S.H., E-mail: shzhang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Cheng, M. [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Z.X. [Beijing Institute of Aeronautica1 Materials, Beijing 100095 (China)

2010-01-15

The hot working characteristics of {delta} phase in the delta-processed Inconel 718 alloy during isothermal compression deformation at temperature of 950 deg. C and strain rate of 0.005 s{sup -1}, were studied by using optical microscope, scanning electron microscope and quantitative X-ray diffraction technique. The results showed that the dissolution of plate-like {delta} phase and the precipitation of spherical {delta} phase particles coexisted during the deformation, and the content of {delta} phase decreased from 7.05 wt.% to 5.14 wt.%. As a result of deformation breakage and dissolution breakage, the plate-like {delta} phase was spheroidized and transferred to spherical {delta} phase particles. In the center with largest strain, the plate-like {delta} phase disappeared and spherical {delta} phase appeared in the interior of grains and grain boundaries.

A Tunable Low Noise Active Bandpass Filter Using a Noise Canceling Technique

OpenAIRE

Soltani, N.

2016-01-01

A monolithic tunable low noise active bandpass filter is presented in this study. Biasing voltages can control the center frequency and quality factor. By keeping the gain constant, the center frequency shift is 300 MHz. The quality factor can range from 90 to 290 at the center frequency. By using a noise cancelling circuit, noise is kept lower than 2.8 dB. The proposed filter is designed using MMIC technology with a center frequency of 2.4 GHz and a power consumption of 180 mW. ED02AH techno...

Delta antibody radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Kselikova, M; Urbankova, J

1985-11-15

The principle and procedure are described of the radioimmunoassay of delta antibody (delta-Ab) using the ABBOTT ANTI-DELTA kit by Abbott Co. A description is given of the kit, the working procedure and the method of evaluation. The results are reported of the incidence of delta-Ab in sera of patients with viral hepatitis B, in haemophiliacs, carriers of the hepatitis B virus surface antigen (HBsAg) and blood donors. The presence was detected of delta-Ab in one HBsAg carrier. The necessity is emphasized of delta-Ab determinations in the blood of donors in view of the antibody transfer with blood and blood preparations.

Mean proloculus size, delta super(13) C and delta super(18) O variations in recent benthic foraminifera from the west coast of India and their climatic implications

Digital Repository Service at National Institute of Oceanography (India)

Nigam, R.; Sarkar, A.

The interrelationship between mean proloculus size (MPS), delta super(18) O and delta super(13) C vatiations in benthic foraminiferal species Rotalidium annectens and their relation with temperature (T) and salinity (S) have been studied in samples...

The first hop: Use of Beaufort Sea deltas by hatch-year semipalmated sandpipers

Science.gov (United States)

Churchwell, Roy T.; Kendall, Steve J.; Brown, Stephen C.; Blanchard, Arny L.; Hollmen, Tuula E.; Powell, Abby

2018-01-01

River deltas along Alaska’s Beaufort Sea coast are used by hatch-year semipalmated sandpipers (Calidris pusilla) after leaving their terrestrial natal sites, but the drivers of their use of these stopover sites on the first “hop” of fall migration are unknown. We quantified sandpiper temporal distribution and abundance as related to food resources at three river deltas during the beginning of their fall migration (post-breeding period) to compare the habitat quality among these deltas. We conducted population counts, sampled invertebrates, and captured birds to collect blood samples from individuals for triglyceride and stable isotope analyses to determine fattening rates and diet. Patterns of sandpiper and invertebrate abundance were complex and varied among deltas and within seasons. River deltas were used by sandpipers from late July to late August, and peak sandpiper counts ranged from 1000 to 4000 individuals, of which 98% were hatch-year semipalmated sandpipers. Isotopic signatures from blood plasma samples indicated that birds switched from a diet of upland tundra to delta invertebrate taxa as the migration season progressed, suggesting a dependence on delta invertebrates. Despite differences in diet among deltas, we found no differences in fattening rates of juvenile sandpipers as indicated by triglyceride levels. The number of sandpipers was positively associated with abundance of Amphipoda and Oligochaeta at the Jago and Okpilak-Hulahula deltas; an isotopic mixing model indicated that sandpipers consumed Amphipoda and Oligochaeta at Jago, mostly Chironomidae at Okpilak-Hulahula and Spionidae at Canning. Regardless of the difference in sandpiper diets at the Beaufort Sea deltas, their similar fattening rates throughout the season indicate that all of these stopover sites provide a critical food resource for hatch-year sandpipers beginning their first migration.

A novel mouse PKC{delta} splice variant, PKC{delta}IX, inhibits etoposide-induced apoptosis

Energy Technology Data Exchange (ETDEWEB)

Kim, Jung D. [School of Biological Sciences, University of Ulsan, Ulsan (Korea, Republic of); Seo, Kwang W. [Department of Internal Medicines, Ulsan University Hospital and School of Medicine, University of Ulsan, Ulsan (Korea, Republic of); Lee, Eun A.; Quang, Nguyen N. [School of Biological Sciences, University of Ulsan, Ulsan (Korea, Republic of); Cho, Hong R. [Department of Surgery, Ulsan University Hospital and School of Medicine, University of Ulsan, Ulsan (Korea, Republic of); Biomedical Research Center, Ulsan University Hospital and School of Medicine, University of Ulsan, Ulsan (Korea, Republic of); Kwon, Byungsuk, E-mail: bskwon@mail.ulsan.as.kr [School of Biological Sciences, University of Ulsan, Ulsan (Korea, Republic of); Biomedical Research Center, Ulsan University Hospital and School of Medicine, University of Ulsan, Ulsan (Korea, Republic of)

2011-07-01

Highlights: {yields} A novel PKC{delta} isoform, named PKC{delta}IX, that lacks the C1 domain and the ATP-binding site is ubiquitously expressed. {yields} PKC{delta}IX inhibits etoposide-induced apoptosis. {yields} PKC{delta}IX may function as an endogenous dominant negative isoform for PKC{delta}. -- Abstract: Protein kinase C (PKC) {delta} plays an important role in cellular proliferation and apoptosis. The catalytic fragment of PKC{delta} generated by caspase-dependent cleavage is essential for the initiation of etoposide-induced apoptosis. In this study, we identified a novel mouse PKC{delta} isoform named PKC{delta}IX (Genebank Accession No. (HQ840432)). PKC{delta}IX is generated by alternative splicing and is ubiquitously expressed, as seen in its full-length PKC{delta}. PKC{delta}IX lacks the C1 domain, the caspase 3 cleavage site, and the ATP binding site but preserves an almost intact c-terminal catalytic domain and a nuclear localization signal (NLS). The structural characteristics of PKC{delta}IX provided a possibility that this PKC{delta} isozyme functions as a novel dominant-negative form for PKC{delta} due to its lack of the ATP-binding domain that is required for the kinase activity of PKC{delta}. Indeed, overexpression of PKC{delta}IX significantly inhibited etoposide-induced apoptosis in NIH3T3 cells. In addition, an in vitro kinase assay showed that recombinant PKC{delta}IX protein could competitively inhibit the kinase activity of PKC{delta}. We conclude that PKC{delta}IX can function as a natural dominant-negative inhibitor of PKC{delta}in vivo.

Delta Dynamics

DEFF Research Database (Denmark)

Bendixen, Mette

. The warming air temperature affects the soil temperature and permafrost thaws and destabilizes the material in the coastal zone. In Greenland, the warming temperature lowers the surface mass balance of the Greenland Ice Sheet and more material is transported to the coastal zone. The sea ice extent is thinning...... of a fjord and the second type is a wider fan-shaped open delta. Most deltas are directly coupled to the Greenland Ice Sheet or local icecaps and are highly influenced by the dynamics in the catchments. It is demonstrated how a modern changing climate directly affects delta dynamics, and that Greenlandic...... deltas are prograding, contrary to the global trend showing eroding Arctic coasts. Moreover, it is revealed that the increasing proglacial freshwater runoff, caused by a lowering of the surface mass balance of the Greenland Ice Sheet is the main determining agent in delta progradation. The final part...

Holocene evolution of a wave-dominated fan-delta: Godavari delta, India

Science.gov (United States)

Saito, Y.; Nageswara Rao, K.; Nagakumar, K.; Demudu, G.; Rajawat, A.; Kubo, S.; Li, Z.

2013-12-01

The Godavari delta is one of the world's largest wave-dominated deltas. The Godavari River arises in the Western Ghats near the west coast of India and drains an area of about 3.1x10^5 km^2, flowing about 1465 km southeast across the Indian peninsula to the Bay of Bengal. The Godavari delta consists of a gentle seaward slope from its apex (12 m elevation) at Rajahmundry and a coastal beach-ridge plain over a distance of about 75 km and covers ~5200 km^2 as a delta plain. The river splits into two major distributary channels, the Gautami and the Vasishta, at a barrage constructed in the mid-1800s. The coastal environment of the deltaic coast is microtidal (~1 m mean tidal range) and wave-dominated (~1.5 m mean wave height in the June-September SW monsoon season, ~0.8 m in the NE monsoon season). Models of the Holocene evolution of the Godavari delta have changed from a zonal progradation model (e.g. Nageswara Rao & Sadakata, 1993) to a truncated cuspate delta model (Nageswara Rao et al., 2005, 2012). Twelve borehole cores (340 m total length), taken in the coastal delta plain during 2010-2013, yielded more than 100 C-14 dates. Sediment facies and C-14 dates from these and previous cores and remote-sensing data support a new delta evolution model. The Holocene coastal delta plain is divided into two parts by a set of linear beach ridges 12-14 km landward from the present shoreline in the central part of the delta. The location of the main depocenter (lobe) has shifted during the Holocene from 1) the center to 2) the west, 3) east, 4) center, 5) west, and 6) east. The linear beach ridges separate the first three from the last three stages. These lobe shifts are controlled by river channel shifts near the apex. Just as the current linear shoreline of the central part of the delta and the concave-up nearshore topography are the result of coastal erosion of a cuspate delta, the linear beach ridges indicate a former eroded shoreline. An unconformity within the deltaic

A Tunable Low Noise Active Bandpass Filter Using a Noise Canceling Technique

Directory of Open Access Journals (Sweden)

N. Soltani

2016-12-01

Full Text Available A monolithic tunable low noise active bandpass filter is presented in this study. Biasing voltages can control the center frequency and quality factor. By keeping the gain constant, the center frequency shift is 300 MHz. The quality factor can range from 90 to 290 at the center frequency. By using a noise cancelling circuit, noise is kept lower than 2.8 dB. The proposed filter is designed using MMIC technology with a center frequency of 2.4 GHz and a power consumption of 180 mW. ED02AH technology is used to simulate the circuit elements.

Antinociceptive activity of Delta9-tetrahydrocannabinol non-ionic microemulsions.

Science.gov (United States)

Lazzari, P; Fadda, P; Marchese, G; Casu, G L; Pani, L

2010-06-30

Delta(9)-Tetrahydrocannabinol (Delta(9)-THC), the major psychoactive constituent of Cannabis sativa L., has been widely studied for its potential pharmaceutical application in the treatment of various diseases and disturbs. This sparingly soluble terpeno-phenolic compound is not easy to handle and to be formulated in pharmaceutical preparations. The aim of this work was to develop a stable aqueous Delta(9)-THC formulation acceptable for different ways of administration, and to evaluate the therapeutic properties of the new Delta(9)-THC based preparation for pain treatment. Due to the thermodynamic stability and advantages of microemulsion based systems, the study was focused on the identification of aqueous microemulsion based systems containing Delta(9)-THC. Oil in water Delta(9)-THC microemulsions were individuated through phase diagrams construction, using the non-ionic surfactant Solutol HS15, being this surfactant acceptable for parenteral administration in human. A selected microemulsion samples containing 0.2 wt% of Delta(9)-THC, stable up to 52 degrees C, was successfully assayed on animal models of pain. Significant antinociceptive activity has been detected by both intraperitoneal and intragastric administration of the new Delta(9)-THC pharmaceutical preparation. The effect has been highlighted in shorter time if compared to a preparation of the same active principle based on previously reported conventional preparation. 2010 Elsevier B.V. All rights reserved.

An automated technique for measuring deltaD and delta18O values of porewater by direct CO2 and H2 equilibration.

Science.gov (United States)

Koehler, G; Wassenaar, L I; Hendry, M J

2000-11-15

The stable-oxygen and -hydrogen isotopic values (deltaD, delta18O) of porewater in geologic media are commonly determined on water obtained by extraction techniques such as centrifugation, mechanical squeezing, vacuum heating and cryogenic microdistillation, and azeotropic distillation. Each of these techniques may cause isotopic fractionation as part the extraction process and each is laborious. Here we demonstrate a new approach to obtain automated, high-precision deltaD and delta18O measurements of porewater in geologic sediments by direct H2- and CO2-porewater equilibration using a modified commercial CO2-water equilibrator. This technique provides an important and cost-effective improvement over current extraction methods, because many samples can be rapidly analyzed with minimal handling, thereby reducing errors and potential for isotopic fractionation. The precision and accuracy of direct H2- and CO2-porewater equilibration is comparable to or better than current porewater extraction methods. Finally, the direct equilibration technique allows investigators to obtain high-resolution (cm scale) porewater deltaD and delta18O profiles using cores from individual boreholes, eliminating the need for costly piezometers or conventional porewater extractions.

Anaerobic Transformation of Furfural by Methanococcus deltae (Delta)LH

Science.gov (United States)

Belay, N.; Boopathy, R.; Voskuilen, G.

1997-01-01

Methanococcus deltae (Delta)LH was grown on H(inf2)-CO(inf2) in the presence of various concentrations of furfural. Furfural at higher concentrations, namely, 20 and 25 mM, inhibited growth of this organism. At concentration of 5 and 10 mM, no inhibition of growth was observed. The other methanogens in this study were not inhibited by 10 mM furfural. Among the methanogens tested, M. deltae was capable of transforming furfural, whereas Methanobacterium thermoautotrophicum Marburg, Methanosarcina barkeri 227, Methanococcus thermolithotrophicus, and Methanobrevibacter ruminantium lacked this capability. One hundred percent removal of furfural was observed within 48 h of incubation in M. deltae cultures. The end product observed during furfural metabolism was furfuryl alcohol. An almost stoichiometric amount of furfuryl alcohol was produced by M. deltae. This transformation is likely to be of value in the detoxification of furfural and in its ultimate conversion to methane and CO(inf2) by anaerobic digestion. PMID:16535618

Determination of delta9-tetrahydrocannabinol in indoor air as an indicator of marijuana cigarette smoking using adsorbent sampling and in-injector thermal desorption gas chromatography-mass spectrometry.

Science.gov (United States)

Chou, Su-Lien; Ling, Yong-Chien; Yang, Mo-Hsiung; Pai, Chung-Yen

2007-08-13

The marijuana leaves are usually mixed with tobaccos and smoked at amusement places in Taiwan. Recently, for investigation-legal purposes, the police asked if we can identify the marijuana smoke in a KTV stateroom (a private room at the entertainment spot for singing, smoking, alcohol drinking, etc.) without marijuana residues. A personal air-sampler pump fitted with the GC liner-tube packed with Tenax-TA adsorbent was used for air sampling. The GC-adsorbent tube was placed in the GC injector port and desorbed directly, followed by GC-MS analysis for the determination of delta9-tetrahydrocannabinol (delta9-THC) in indoor air. The average desorption efficiency and limit of detection for delta9-THC were 89% and 0.1 microg m(-3), respectively, approximately needing 1.09 mg of marijuana leaves smoked in an unventilated closed room (3.0 m x 2.4 m x 2.7 m) to reach this level. The mean delta9-THC contained in the 15 marijuana plants seized from diverse locations was measured to be 0.32%. The delta9-THC in room air can be successfully identified from mock marijuana cigarettes, mixtures of marijuana and tobacco, and an actual case. The characteristic delta9-THC peak in chromatogram can serve as the indicator of marijuana. Positive result suggests marijuana smoking at the specific scene in the recent past, facilitating the formulation of further investigation.

Controls of {delta}{sup 34}S and {delta}{sup 18}O in dissolved sulphate: Learning from a detailed survey in the Llobregat River (Spain)

Energy Technology Data Exchange (ETDEWEB)

Otero, Neus [Departament Cristal . lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028 Barcelona (Spain); Grup d' Hidrogeoquimica, Departament de Geologia Ambiental, Institut de Ciencies de la Terra ' Jaume Almera' , CSIC, Lluis Sole i Sabaris, s/n, 08028 Barcelona (Spain)], E-mail: notero@ub.edu; Soler, Albert; Canals, Angels [Departament Cristal . lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028 Barcelona (Spain)

2008-05-15

The S and O isotopic composition of dissolved SO{sub 4}, used as a tracer for SO{sub 4} sources, was applied to the water of the Llobregat River system (NE Spain). The survey was carried out at 30 sites where surface water was sampled on a monthly basis over a period of 2a. The concentration of dissolved SO{sub 4} varied from 20 to 1575 mg L{sup -1}. Sulphur isotopic compositions clustered in two populations: one - 93% of the samples - had positive values with a mode of +9 per mille ; the other had negative values and a mode of -5 per mille . Data for {delta}{sup 18}O{sub SO{sub 4}} showed a mean value of +11 per mille , with no bi-modal distribution, though lower values of {delta}{sup 18}O corresponded to samples with negative {delta}{sup 34}S. These values can not be explained solely by the contribution of bedrock SO{sub 4} sources: that is, sulphide oxidation and the weathering of outcrops of sulphates, though numerous chemical sediments exist in the basin. Even in a river with a high concentration of natural sources of dissolved SO{sub 4}, such as the Llobregat River, the {delta}{sup 34}S values suggest that dissolved SO{sub 4} is controlled by a complex mix of both natural and anthropogenic sources. The main anthropogenic sources in this basin are fertilizers, sewage, potash mine effluent and power plant emissions. Detailed river water sampling, together with the chemical and isotopic characterisation of the main anthropogenic inputs, allowed determination of the influence of redox processes, as well as identification of the contribution of natural and anthropogenic SO{sub 4} sources and detection of spatial variations and seasonal changes among these sources. For instance, in the Llobregat River the input of fertilisers is well marked seasonally. Minimum values of {delta}{sup 34}S are reported during fertilization periods - from January to March - indicating a higher contribution of this source. The dual isotope approach, {delta}{sup 34}S and {delta}{sup 18}O

Compact Dual-Band Bandpass Filter Using Stubs Loaded Ring Resonator

Science.gov (United States)

Xu, Jin

2016-01-01

This paper presents a novel second-order dual-band bandpass filter (BPF) by using proposed stubs loaded ring resonator. The resonant behavior of proposed stubs loaded ring resonator is analyzed by even-/odd-mode method, which shows its multiple-mode resonant characteristic. Parameters sweep is done so as to give the design guidelines. As an example, a second-order dual-band BPF operating at 1.8/5.2 GHz for GSM and WLAN applications is designed, fabricated and measured. The fabricated filter has a very compact size of 0.05λg×0.15λg. Measured results also show that the proposed dual-band BPF has a better than 20 dB rejection upper stopband from 5.47 GHz to 12.56 GHz. Good agreement is shown between the simulated and measured results.

delta-vision

Data.gov (United States)

California Natural Resource Agency — Delta Vision is intended to identify a strategy for managing the Sacramento-San Joaquin Delta as a sustainable ecosystem that would continue to support environmental...

Miniaturized bandpass filter using a meandered stepped-impedance resonator with a meandered-line stub-load on a GaAs substrate.

Science.gov (United States)

Chuluunbaatar, Z; Wang, C; Kim, N Y

2014-01-01

This paper reports a compact bandpass filter with improved skirt selectivity using integrated passive device fabrication technology on a GaAs substrate. The structure of the filter consists of electromagnetically coupled meandered-line symmetric stepped-impedance resonators. The strength of the coupling between the resonators is enhanced by using a meandered-line stub-load inside the resonators to improve the selectivity and miniaturize the size of the filter. In addition, the center frequency of the filter can be flexibly controlled by varying degrees of the capacitive coupling between resonator and stub-load. To verify the proposed concept, a protocol bandpass filter with center frequency of 6.53 GHz was designed, fabricated, and measured, with a return loss and insertion loss of 39.1 dB and 1.63 dB.

Growth laws for delta crevasses in the Mississippi River Delta: observations and modeling

Science.gov (United States)

Yocum, T. A.; Georgiou, I. Y.

2016-02-01

River deltas are accumulations of sedimentary deposits delivered by rivers via a network of distributary channels. Worldwide they are threatened by environmental changes, including subsidence, global sea level rise and a suite of other local factors. In the Mississippi River Delta (MRD) these impacts are exemplified, and have led to proposed solutions to build land that include sediment diversions, thereby reinitiating the delta cycle. While economically efficient, there are too few analogs of small deltas aside from laboratory studies, numerical modeling studies, theoretical approaches, and limited field driven observations. Anthropogenic crevasses in the modern delta are large enough to overcome limitations of laboratory deltas, and small enough to allow for "rapid" channel and wetland development, providing an ideal setting to investigate delta development mechanics. Crevasse metrics were obtained using a combination of geospatial tools, extracting key parameters (bifurcation length and width, channel order and depth) that were non-dimensionalized and compared to river-dominated delta networks previously studied. Analysis showed that most crevasses in the MRD appear to obey delta growth laws and delta allometry relationships, suggesting that crevasses do exhibit similar planform metrics to larger Deltas; the distance to mouth bar versus bifurcation order demonstrated to be a very reasonable first order estimate of delta-top footprint. However, some crevasses exhibited different growth metrics. To better understand the hydrodynamic and geomorphic controls governing crevasse evolution in the MRD, we assess delta dynamics via a suite of field observations and numerical modeling in both well-established and newly constructed crevasses. Our analysis suggests that delta development is affected by the relative influence of external (upstream and downstream) and internal controls on the hydrodynamic and sediment transport patterns in these systems.

COMMD1 regulates the delta epithelial sodium channel ({delta}ENaC) through trafficking and ubiquitination

Energy Technology Data Exchange (ETDEWEB)

Chang, Tina; Ke, Ying; Ly, Kevin [Department of Physiology, University of Otago, P.O. Box 913, Dunedin 9054 (New Zealand); McDonald, Fiona J., E-mail: fiona.mcdonald@otago.ac.nz [Department of Physiology, University of Otago, P.O. Box 913, Dunedin 9054 (New Zealand)

2011-08-05

Highlights: {yields} The COMM domain of COMMD1 mediates binding to {delta}ENaC. {yields} COMMD1 reduces the cell surface population of {delta}ENaC. {yields} COMMD1 increases the population of {delta}ENaC-ubiquitin. {yields} Both endogenous and transfected {delta}ENaC localize with COMMD1 and transferrin suggesting they are located in early/recycling endosomes. -- Abstract: The delta subunit of the epithelial sodium channel ({delta}ENaC) is a member of the ENaC/degenerin family of ion channels. {delta}ENaC is distinct from the related {alpha}-, {beta}- and {gamma}ENaC subunits, known for their role in sodium homeostasis and blood pressure control, as {delta}ENaC is expressed in brain neurons and activated by external protons. COMMD1 (copper metabolism Murr1 domain 1) was previously found to associate with and downregulate {delta}ENaC activity. Here, we show that COMMD1 interacts with {delta}ENaC through its COMM domain. Co-expression of {delta}ENaC with COMMD1 significantly reduced {delta}ENaC surface expression, and led to an increase in {delta}ENaC ubiquitination. Immunocytochemical and confocal microscopy studies show that COMMD1 promoted localization of {delta}ENaC to the early/recycling endosomal pool where the two proteins were localized together. These results suggest that COMMD1 downregulates {delta}ENaC activity by reducing {delta}ENaC surface expression through promoting internalization of surface {delta}ENaC to an intracellular recycling pool, possibly via enhanced ubiquitination.

SEMICONDUCTOR INTEGRATED CIRCUITS: An asymmetric MOSFET-C band-pass filter with on-chip charge pump auto-tuning

Science.gov (United States)

Fangxiong, Chen; Min, Lin; Heping, Ma; Hailong, Jia; Yin, Shi; Forster, Dai

2009-08-01

An asymmetric MOSFET-C band-pass filter (BPF) with on chip charge pump auto-tuning is presented. It is implemented in UMC (United Manufacturing Corporation) 0.18 μm CMOS process technology. The filter system with auto-tuning uses a master-slave technique for continuous tuning in which the charge pump outputs 2.663 V, much higher than the power supply voltage, to improve the linearity of the filter. The main filter with third order low-pass and second order high-pass properties is an asymmetric band-pass filter with bandwidth of 2.730-5.340 MHz. The in-band third order harmonic input intercept point (IIP3) is 16.621 dBm, with 50 Ω as the source impedance. The input referred noise is about 47.455 μVrms. The main filter dissipates 3.528 mW while the auto-tuning system dissipates 2.412 mW from a 1.8 V power supply. The filter with the auto-tuning system occupies 0.592 mm2 and it can be utilized in GPS (global positioning system) and Bluetooth systems.

A robust and fast method of sampling and analysis of delta13C of dissolved inorganic carbon in ground waters.

Science.gov (United States)

Spötl, Christoph

2005-09-01

The stable carbon isotopic composition of dissolved inorganic carbon (delta13C(DIC)) is traditionally determined using either direct precipitation or gas evolution methods in conjunction with offline gas preparation and measurement in a dual-inlet isotope ratio mass spectrometer. A gas evolution method based on continuous-flow technology is described here, which is easy to use and robust. Water samples (100-1500 microl depending on the carbonate alkalinity) are injected into He-filled autosampler vials in the field and analysed on an automated continuous-flow gas preparation system interfaced to an isotope ratio mass spectrometer. Sample analysis time including online preparation is 10 min and overall precision is 0.1 per thousand. This method is thus fast and can easily be automated for handling large sample batches.

Future Deltas Utrecht University research focus area: towards sustainable management of sinking deltas

Science.gov (United States)

Stouthamer, E.; van Asselen, S.

2015-11-01

Deltas are increasingly under pressure from human impact and climate change. To deal with these pressures that threat future delta functioning, we need to understand interactions between physical, biological, chemical and social processes in deltas. This requires an integrated approach, in which knowledge on natural system functioning is combined with knowledge on spatial planning, land and water governance and legislative frameworks. In the research focus area Future Deltas of Utrecht University an interdisciplinary team from different research groups therefore works together. This allows developing integrated sustainable and resilient delta management strategies, which is urgently needed to prevent loss of vital delta services.

W-band waveguide bandpass filter with E-plane cut

DEFF Research Database (Denmark)

Furtula, Vedran; Salewski, Mirko

2014-01-01

In this paper, we present a design and measurements of a five-section bandpass filter with a passband from 96 to 106 GHz. The insertion loss is less than 1.4 dB in the passband, and the rejection is better than 40 dB in the range from 115 to 142 GHz. We use transmission line coupling theory based...... on Tchebyscheff’s synthesis in order to provide an initial guess for the geometrical parameters of the filter such as cavity lengths and coupling widths. The filter is manufactured from brass in two halves in the E-plane cut topology. The S-parameters of the filter are measured and compared with the simulations....... The measured passband insertion loss is approximately 0.4 dB worse than in the simulation, and the measured passband width is approximately 3.4% narrower. The measured filter attenuation roll-off corresponds well to the simulation. We also compare our S-parameter measurements of the E-plane filter...

Miniaturized Bandpass Filter Using a Meandered Stepped-Impedance Resonator with a Meandered-Line Stub-Load on a GaAs Substrate

Directory of Open Access Journals (Sweden)

Z. Chuluunbaatar

2014-01-01

Full Text Available This paper reports a compact bandpass filter with improved skirt selectivity using integrated passive device fabrication technology on a GaAs substrate. The structure of the filter consists of electromagnetically coupled meandered-line symmetric stepped-impedance resonators. The strength of the coupling between the resonators is enhanced by using a meandered-line stub-load inside the resonators to improve the selectivity and miniaturize the size of the filter. In addition, the center frequency of the filter can be flexibly controlled by varying degrees of the capacitive coupling between resonator and stub-load. To verify the proposed concept, a protocol bandpass filter with center frequency of 6.53 GHz was designed, fabricated, and measured, with a return loss and insertion loss of 39.1 dB and 1.63 dB.

Potency trends of delta9-THC and other cannabinoids in confiscated marijuana from 1980-1997.

Science.gov (United States)

ElSohly, M A; Ross, S A; Mehmedic, Z; Arafat, R; Yi, B; Banahan, B F

2000-01-01

The analysis of 35,312 cannabis preparations confiscated in the USA over a period of 18 years for delta-9-tetrahydrocannabinol (delta9-THC) and other major cannabinoids is reported. Samples were identified as cannabis, hashish, or hash oil. Cannabis samples were further subdivided into marijuana (loose material, kilobricks and buds), sinsemilla, Thai sticks and ditchweed. The data showed that more than 82% of all confiscated samples were in the marijuana category for every year except 1980 (61%) and 1981 (75%). The potency (concentration of delta9-THC) of marijuana samples rose from less than 1.5% in 1980 to approximately 3.3% in 1983 and 1984, then fluctuated around 3% till 1992. Since 1992, the potency of confiscated marijuana samples has continuously risen, going from 3.1% in 1992 to 4.2% in 1997. The average concentration of delta9-THC in all cannabis samples showed a gradual rise from 3% in 1991 to 4.47% in 1997. Hashish and hash oil, on the other hand, showed no specific potency trends. Other major cannabinoids [cannabidiol (CBD), cannabinol (CBN), and cannabichromene (CBC)] showed no significant change in their concentration over the years.

Geochronology of priority pollutants in sedimentation zones of the Volga and Danube delta in comparison with the Rhine delta

International Nuclear Information System (INIS)

Winkels, H.J.; Kroonenberg, S.B.; Lychagin, M.Y.; Marin, G.; Rusakov, G.V.; Kasimov, N.S.

1998-01-01

Six sediment cores were taken in sedimentation zones of the Volga river (located in the southern part of the Russian Federation) and, additionally, 6 sediment cores were taken in several lakes (sedimentation zones) in the central and western part of the Danube delta in Romania. Priority pollutants (8 metals, 7 polychlorinated biphenyls and 10 polycyclic aromatic hydrocarbons) were determined in all samples of all cores. Present-day and historical levels of pollutants since the late 1930s were established through the use of radionuclide time tracers ( 137 Cs, 134 Cs). For the persistent metals and polycyclic aromatic hydrocarbons, trends in the concentration profiles during the last 5 decades are described. Low and hardly changing concentrations of As, Cu, Zn and all studied PAHs were observed during the last five decades in the sediments of the Volga river. Recently deposited sediments show slightly increasing levels for the heavy metals Zn and Cr and As in the Volga delta. For the studied metals and PAHs, maximum concentrations were found around 1987 in the sediments of the Danube delta. Sediments deposited around 1940 and recently deposited sediments in the Danube delta showed lower pollutant levels. If the contents of heavy metals, PAHs and PCBs in the aquatic sediments in the deltas of the rivers Rhine, Danube and Volga are compared, it is clear that the Volga delta is and was the cleanest delta during the last 5 decades. Nowadays the contents of heavy metals (except Cu and Ni), PAHs and PCBs in the aquatic sediments of the river Rhine are still highest compared to the other two rivers. The recent load of heavy metals (except Cd and Zn) in the sediments of the river Danube is the highest compared to the other two rivers. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Differential entrainment of neuroelectric delta oscillations in developmental dyslexia.

Directory of Open Access Journals (Sweden)

Fruzsina Soltész

Full Text Available Oscillatory entrainment to the speech signal is important for language processing, but has not yet been studied in developmental disorders of language. Developmental dyslexia, a difficulty in acquiring efficient reading skills linked to difficulties with phonology (the sound structure of language, has been associated with behavioural entrainment deficits. It has been proposed that the phonological 'deficit' that characterises dyslexia across languages is related to impaired auditory entrainment to speech at lower frequencies via neuroelectric oscillations (<10 Hz, 'temporal sampling theory'. Impaired entrainment to temporal modulations at lower frequencies would affect the recovery of the prosodic and syllabic structure of speech. Here we investigated event-related oscillatory EEG activity and contingent negative variation (CNV to auditory rhythmic tone streams delivered at frequencies within the delta band (2 Hz, 1.5 Hz, relevant to sampling stressed syllables in speech. Given prior behavioural entrainment findings at these rates, we predicted functionally atypical entrainment of delta oscillations in dyslexia. Participants performed a rhythmic expectancy task, detecting occasional white noise targets interspersed with tones occurring regularly at rates of 2 Hz or 1.5 Hz. Both groups showed significant entrainment of delta oscillations to the rhythmic stimulus stream, however the strength of inter-trial delta phase coherence (ITC, 'phase locking' and the CNV were both significantly weaker in dyslexics, suggestive of weaker entrainment and less preparatory brain activity. Both ITC strength and CNV amplitude were significantly related to individual differences in language processing and reading. Additionally, the instantaneous phase of prestimulus delta oscillation predicted behavioural responding (response time for control participants only.

Connectivity in river deltas

Science.gov (United States)

Passalacqua, P.; Hiatt, M. R.; Sendrowski, A.

2016-12-01

Deltas host approximately half a billion people and are rich in ecosystem diversity and economic resources. However, human-induced activities and climatic shifts are significantly impacting deltas around the world; anthropogenic disturbance, natural subsidence, and eustatic sea-level rise are major causes of threat to deltas and in many cases have compromised their safety and sustainability, putting at risk the people that live on them. In this presentation, I will introduce a framework called Delta Connectome for studying connectivity in river deltas based on different representations of a delta as a network. Here connectivity indicates both physical connectivity (how different portions of the system interact with each other) as well as conceptual (pathways of process coupling). I will explore several network representations and show how quantifying connectivity can advance our understanding of system functioning and can be used to inform coastal management and restoration. From connectivity considerations, the delta emerges as a leaky network that evolves over time and is characterized by continuous exchanges of fluxes of matter, energy, and information. I will discuss the implications of connectivity on delta functioning, land growth, and potential for nutrient removal.

Suspended sediment data analysis: Mackenzie Delta, NWT 1992-93 update [and] Westbank Tributaries, Mackenzie River, NWT

Energy Technology Data Exchange (ETDEWEB)

Carson, M A

1993-03-01

A full analysis and review of sediment data collected in 1991 as part of a program dealing with sediment-related aspects of northern hydrocarbon development is presented. The data were collected at two delta-head stations, three mid-delta stations, and three outer-delta stations. The primary purpose of the program is to obtain mathematical relationships that will allow prediction of sediment concentration at delta stations in the absence of actual sampling. This task is a prerequisite to the development of a sediment adjunct to the one-dimensional hydraulic model being developed for the delta. Preliminary analysis indicates strong correlations between sediment concentrations at different stations in the delta. It is tentatively proposed that sediment concentrations at all east-central stations in the delta could be predicted from samples concentrations at Inuvik, and that concentrations on the west side could be predictable from Peel River Station. The second part of this report deals with suspended sediment data analysis for the westbank tributaries of the Mackenzie River. 19 refs., 36 figs., 29 tabs.

A dense grid of narrow bandpass steep edge filters for the JST/T250 telescope: summary of results

Science.gov (United States)

Brauneck, U.; Sprengard, R.; Bourquin, S.; Marín-Franch, A.

2017-09-01

On the Javalambre mountain in Spain, the Centro de Estudios de Fisica del Cosmos de Aragon (CEFCA) has setup a new wide field telescope, the JST/T250: a 2.55 m telescope with a plate scale of 22.67"/mm and a 3° diameter field of view. To conduct a photometric sky survey, a large format mosaic camera made of 14 individual CCDs is used in combination with filter trays containing 14 filters each of theses 101.7 x 96.5 mm in size. For this instrument, SCHOTT manufactured 56 specially designed steep edged bandpass interference filters which were recently completed. The filter set consists of bandpass filters in the range between 348,5 nm and 910 nm and a longpass filter at 915 nm. Most of the filters have FWHM of 14.5 nm and a blocking between 250 and 1050 nm with optical density of OD5. Absorptive color glass substrates in combination with interference filters were used to minimize residual reflection in order to avoid ghost images. Inspite of containing absorptive elements, the filters show the maximum possible transmission. This was achieved by using magnetron sputtering for the filter coating process. The most important requirement for the continuous photometric survey is the tight tolerancing of the central wavelengths and FWHM of the filters. This insures each bandpass having a defined overlap with its neighbors. In addition, the blocking of the filters is better than OD5 in the range 250-1050 nm. A high image quality required a low transmitted wavefront error (

Passive air sampling of organochlorine pesticides and polychlorinated biphenyls in the Yangtze River Delta, China: Concentrations, distributions, and cancer risk assessment

International Nuclear Information System (INIS)

Zhang, Lifei; Dong, Liang; Yang, Wenlong; Zhou, Li; Shi, Shuangxin; Zhang, Xiulan; Niu, Shan; Li, Lingling; Wu, Zhongxiang; Huang, Yeru

2013-01-01

The Yangtze River Delta (YRD) has been quickly industrialized and urbanized. Passive air sampling of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) was carried out in the YRD in 2010–2011 to investigate their spatiotemporal distributions and estimate the risk of cancer from their inhalation. Annual concentrations were 151, 168, 18.8, 110, 17.9, and 35.0 pg m −3 for HCB, ∑DDTs, ∑HCHs, ∑chlordane, mirex, and PCBs, respectively. The highest OCP and PCB concentrations were generally detected in the autumn and winter. The average concentrations of OCPs and PCBs for the different site groups followed the order urban ≈ urban–rural transition > rural. The lifetime excess cancer risks from the inhalation of OCPs and PCBs were −6 . The predicted cancer cases per lifetime associated with the inhalation of OCPs and PCBs are 12, 7, and 4 per ten thousand people for urban, urban–rural transition, and rural areas, respectively. Highlights: •Organochlorine pollutants were measured in the air in the Yangtze River Delta area. •Air PCB concentration declined in recent years comparing with previous results. •HCB and DDEs predominated, with the highest values in winter and autumn, respectively. •OCPs and PCBs followed the order: urban ≈ urban–rural transition > rural. -- A detailed study of organochlorine pesticides and polychlorinated biphenyls in air across the Yangtze River Delta area using passive air samplers

Delta 2.0

DEFF Research Database (Denmark)

Skott, Jeppe; Skott, Charlotte Krog; Jess, Kristine

DELTA 2.0 er en ny og helt opdateret udgave af Delta, der i ti år været brugt i matematiklærernes grund-, efter- og videreuddannelse. DELTA 2.0 er seriens almene fagdidaktik. Der er også fagdidaktiske overvejelser i de øvrige bøger i serien, men de er knyttet til specifikt matematisk indhold. DELTA...... 2.0 behandler mere generelle matematikdidaktiske problemstillinger såsom læringsteoretiske overvejelser i forbindelse med matematik, centrale aspekter af det at undervise i matematik og digitale teknologier som værktøj til at støtte elevers faglige læring af matematik....

HTS dual-band bandpass filters using stub-loaded hair-pin resonators for mobile communication systems

Energy Technology Data Exchange (ETDEWEB)

Sekiya, N., E-mail: nsekiya@yamanashi.ac.jp; Sugiyama, S.

2014-09-15

Highlights: • We have developed a HTS five-pole dual-band bandpass filter using stub-loaded hair-pin resonators. • The proposed dual-band BPF can independently control of the center frequency. • Flexibly adjustment of the bandwidth can be achieved by the H-shaped waveguide. • The proposed BPF is evaluated by simulation and measurement with good agreement. - Abstract: A HTS dual-band bandpass filter is developed to obtain sharp-cut off characteristics for mobile communication systems. The filter is composed of five stub-loaded hair-pin resonators with H-shaped waveguides between them. The main advantage of the proposed filter is to allow independent control of the center frequency of the first and second bands. The bandwidths can be flexibly adjusted using the H-shaped waveguide. An electromagnetic simulator was used to design and analyze the filter, which have a 3.5-GHz center frequency and a 70-MHz (2%) bandwidth for the first band and a 5.0-GHz center frequency and a 100-MHz (2%) bandwidth for the second band. The filter was fabricated using YBa{sub 2}Cu{sub 3}O{sub y} thin film on an Al{sub 2}O{sub 3} substrate. Ground plane was fabricated using Au thin film. The measured frequency responses of the filter tally well with the simulated ones.

Solar-blind ultraviolet band-pass filter based on metal—dielectric multilayer structures

International Nuclear Information System (INIS)

Wang Tian-Jiao; Xu Wei-Zong; Lu Hai; Ren Fang-Fang; Chen Dun-Jun; Zhang Rong; Zheng You-Dou

2014-01-01

Solar-blind ultraviolet (UV) band-pass filter has significant value in many scientific, commercial, and military applications, in which the detection of weak UV signal against a strong background of solar radiation is required. In this work, a solar-blind filter is designed based on the concept of “transparent metal”. The filter consisting of Al/SiO 2 multilayers could exhibit a high transmission in the solar-blind wavelength region and a wide stopband extending from near-ultraviolet to infrared wavelength range. The central wavelength, bandwidth, Q factor, and rejection ratio of the passband are numerically studied as a function of individual layer thickness and multilayer period. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Peat compaction in deltas : implications for Holocene delta evolution

NARCIS (Netherlands)

van Asselen, S.

2010-01-01

Many deltas contain substantial amounts of peat, which is the most compressible soil type. Therefore, peat compaction potentially leads to high amounts of subsidence in deltas. The main objective of this research was to quantify subsidence due to peat compaction in Holocene fluvial-deltaic settings

Formation of conjugated delta8,delta10-double bonds by delta12-oleic-acid desaturase-related enzymes: biosynthetic origin of calendic acid.

Science.gov (United States)

Cahoon, E B; Ripp, K G; Hall, S E; Kinney, A J

2001-01-26

Divergent forms of the plant Delta(12)-oleic-acid desaturase (FAD2) have previously been shown to catalyze the formation of acetylenic bonds, epoxy groups, and conjugated Delta(11),Delta(13)-double bonds by modification of an existing Delta(12)-double bond in C(18) fatty acids. Here, we report a class of FAD2-related enzymes that modifies a Delta(9)-double bond to produce the conjugated trans-Delta(8),trans-Delta(10)-double bonds found in calendic acid (18:3Delta(8trans,10trans,12cis)), the major component of the seed oil of Calendula officinalis. Using an expressed sequence tag approach, cDNAs for two closely related FAD2-like enzymes, designated CoFADX-1 and CoFADX-2, were identified from a C. officinalis developing seed cDNA library. The deduced amino acid sequences of these polypeptides share 40-50% identity with those of other FAD2 and FAD2-related enzymes. Expression of either CoFADX-1 or CoFADX-2 in somatic soybean embryos resulted in the production of calendic acid. In embryos expressing CoFADX-2, calendic acid accumulated to as high as 22% (w/w) of the total fatty acids. In addition, expression of CoFADX-1 and CoFADX-2 in Saccharomyces cerevisiae was accompanied by calendic acid accumulation when induced cells were supplied exogenous linoleic acid (18:2Delta(9cis,12cis)). These results are thus consistent with a route of calendic acid synthesis involving modification of the Delta(9)-double bond of linoleic acid. Regiospecificity for Delta(9)-double bonds is unprecedented among FAD2-related enzymes and further expands the functional diversity found in this family of enzymes.

Using delta15N- and delta18O-values to identify nitrate sources in karst ground water, Guiyang, southwest China.

Science.gov (United States)

Liu, Cong-Qiang; Li, Si-Liang; Lang, Yun-Chao; Xiao, Hua-Yun

2006-11-15

Nitrate pollution of the karstic groundwater is an increasingly serious problem with the development of Guiyang, the capital city of Guizhou Province, southwest China. The higher content of NO3- in groundwater compared to surface water during both summer and winter seasons indicates that the karstic groundwater system cannot easily recover once contaminated with nitrate. In order to assess the sources and conversion of nitrate in the groundwater of Guiyang, we analyzed the major ions, delta(15)N-NH4+, delta(15)N-NO3-, and delta(18)O-NO3- in surface and groundwater samples collected during both summer and winter seasons. The results show that nitrate is the major dominant species of nitrogen in most water samples and there is a big variation of nitrate sources in groundwater between winter and summer season, due to fast response of groundwater to rain or surface water in the karst area. Combined with information on NO3- /Cl-, the variations of the isotope values of nitrate in the groundwater show a mixing process of multiple sources of nitrate, especially in the summer season. Chemical fertilizer and nitrification of nitrogen-containing organic materials contribute nitrate to suburban groundwater, while the sewage effluents and denitrification mainly control the nitrate distribution in urban groundwater.

Haematological and genetic features of delta beta-thalassaemia in Pakistan

International Nuclear Information System (INIS)

Ahmad, S.; Anwar, M.

2006-01-01

Objective: To describe the hematological and genetic features of delta beta-thalassaemia in Pakistani patients. Design: Descriptive case series. Place and Duration of Study: Department of Pathology, PNS Shifa, Karachi and Department of Hematology, Armed Forces Institute of Pathology, Rawalpindi, from January 1994 to April 2004. Patients and Methods: Thirteen individuals from six unrelated Pakistani families with a hematological diagnosis of delta beta-thalassaemia were studied. A brief clinical history, and the results of blood counts, absolute values, Hb-F, Hb-A/sub 2/, and hemoglobin electrophoresis were recorded. The DNA from each subject was first screened for the delta beta-thalassaemia mutations found in the Pakistani population. The samples were then screened for the Invl Del sup G/gamma(sup A/gamma delta beta). Results: The subjects included six heterozygote, six homozygotes and one compound heterozygote of delta beta and delta beta-thalassaemia. All heterozygote and 4/6 homozygotes were asymptomatic. One homo zygote had thalassaemia intermedia while another had transfusion dependent anemia. The mean Hb, TRBC, MCV, MCH, Hb-F and Hb-A/sub 2/ in delta beta-thalassaemia heterozygote were 11.6 g/dl, 5.37 x 1012/L, 70.9 fl, and 21.7 pg, 14% and 2.6% respectively. The same values in the four un transfused homo zygote were 10.6 g/dl, 5.34x1012/L, 69.211, and 20.8pg, 100% and 0% respectively. The mutation analysis revealed that all 13 individuals had the same Invl Del sup G/gamma(sup A/gamma delta beta). Conclusion: delta beta-thalassaemia is a rare disorder in Pakistan. Although the clinical picture is very mild its combination with delta beta-thalassaemia trait can produce a sever transfusion dependent thalassaemia. The DNA based diagnosis is possible in the prenatal as well as the postnatal period. (author)

Spatio-temporal patterns and predictions of phytoplankton assemblages in a subtropical river delta system

DEFF Research Database (Denmark)

Wang, Chao; Li, Xinhui; Wang, Xiangxiu

2016-01-01

Spatial and seasonal sampling within a subtropical river delta system, the Pearl River Delta (China), provided data to determine seasonal phytoplankton patterns and develop prediction models. The high nutrient levels and frequent water exchanges resulted in a phytoplankton community with greatest...

The dynamics of central Main Ethiopian Rift waters: Evidence from {delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr ratios

Energy Technology Data Exchange (ETDEWEB)

Rango, Tewodros, E-mail: tewodros.godebo@duke.edu [Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708 (United States)] [Addis Ababa University, Department of Earth Sciences, P.O. Box 1176, Addis Ababa (Ethiopia); Petrini, Riccardo; Stenni, Barbara [University of Trieste, Department of Geosciences, Via Weiss 1, I-34100 Trieste (Italy); Bianchini, Gianluca [Istituto di Geoscienze e Georisorse-CNR, Pisa (Italy)] [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Slejko, Francesca [University of Trieste, Department of Geosciences, Via Weiss 1, I-34100 Trieste (Italy); Beccaluva, Luigi [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Ayenew, Tenalem [Addis Ababa University, Department of Earth Sciences, P.O. Box 1176, Addis Ababa (Ethiopia)

2010-12-15

Research highlights: {yields} Chemical and isotope ({delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr) techniques are applied to understand various hydrological processes in the Main Ethiopian Rift. {yields} Some of the studied groundwaters display a depleted {delta}D-{delta}{sup 18}O composition when compared to the present-day average precipitation, thus suggesting that the rift floor aquifers also contains paleo-meteoric waters recharge associated with deep flow system. {yields} The pristine waters coming from the highlands display isotopic compositions characterized by less radiogenic {sup 87}Sr/{sup 86}Sr (and more depleted {delta}D, {delta}{sup 18}O). This isotopic signature subsequently evolves towards higher {sup 87}Sr/{sup 86}Sr by an interaction with the more radiogenic rhyolites of the rift and their weathered and redeposited products. - Abstract: Water samples from cold and geothermal boreholes, hot springs, lakes and rivers were analyzed for {delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr compositions in order to investigate lake water-groundwater mixing processes, water-rock interactions, and to evaluate groundwater flow paths in the central Main Ethiopian Rift (MER) of the Ziway-Shala basin. Different ranges of isotopic values were recorded for different water types: hot springs show {delta}{sup 18}O -3.36 to +3.69 and {delta}D -15.85 to +24.23, deep Aluto-Langano geothermal wells show {delta}{sup 18}O -4.65 to -1.24 and {delta}D -12.39 to -9.31, groundwater wells show {delta}{sup 18}O -3.99 to +5.14 and {delta}D -19.69 to +32.27, whereas the lakes show {delta}{sup 18}O and {delta}D in the range +3.98 to +7.92 and +26.19 to +45.71, respectively. The intersection of the Local Meteoric Water Line (LMWL: {delta}D = 7 {delta}{sup 18}O + 11.2, R{sup 2} = 0.94, n = 42) and the Local Evaporation Line (LEL: {delta}D = 5.63{delta}{sup 18}O + 8, n = 14, R{sup 2} = 0.82) was used to estimate the average isotopic composition of recharge water into the

Prevalence of Toxoplasma gondii in Chicken samples from delta of Egypt using ELISA, histopathology and immunohistochemistry.

Science.gov (United States)

Ibrahim, Hany M; Abdel-Ghaffar, Fathy; Osman, Gamalat Y; El-Shourbagy, Safinaz H; Nishikawa, Yoshifumi; Khattab, Reham A

2016-06-01

Estimates of the zoonotic diseases are helpful for monitoring and improving public health. Laboratory-based surveillance provides crucial information for assessing zoonotic disease trends and developments. Toxoplasmosis is considered as a zoonotic disease and has both medical and veterinary importance since it leads to abortion in humans and several animal species. In view of the worldwide importance of T. gondii, this study aimed to estimate the prevalence of T. gondii in chickens from the Delta of Egypt. A total of 304 blood and brain samples were collected from Egyptian chickens from Gharbiya, Qalyoubiya, Minufiya, Beheira, Kafr EL-Shaykh and Dakahlia Provinces. In order to determine the serological and histopathological prevalence of T. gondii, the samples were examined by ELISA, histopathology and immunohistochemistry (IHC). The prevalence of T. gondii was 11.18, 6.91, 6.91 % by ELISA, histopathology and IHC, respectively. Statistically significant differences in the prevalence of T. gondii were observed on the basis of season, sex and habitat. These data provide valuable information regarding the epidemiology of T. gondii infections in Egyptian chickens, which can be employed in developing efficient strategies for disease management and control.

Hysteretic self-oscillating bandpass current mode control for Class D audio amplifiers driving capacitive transducers

DEFF Research Database (Denmark)

Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

2013-01-01

A hysteretic self-oscillating bandpass current mode control (BPCM) scheme for Class D audio amplifiers driving capacitive transducers are presented. The scheme provides excellent stability margins and low distortion over a wide range of operating conditions. Small-signal behavior of the amplifier...... the rules of electrostatics have been known as very interesting alternatives to the traditional inefficient electrodynamic transducers. When driving capacitive transducers from a Class D audio amplifier the high impedance nature of the load represents a key challenge. The BPCM control scheme ensures a flat...

What fish and how many there are in Danube Delta?

Directory of Open Access Journals (Sweden)

NĂVODARU Ion

2011-09-01

Full Text Available The real figure of fish fauna and fishery of the Danube delta is difficult to be estimated due to the limitation in fish sampling and underreporting of catch. This paper proposes to compare output of fish sampling with commercial catch statistics. Fish fauna from Danube delta complex lakes was sampled in 2006-2008 period and catchstatistics represent a long time series data recording. For fish sampling was used two complementary methods: electric fishing for shallow border zone and Nordic gillnet fishing for deep open water. The frequency of occurrence and the dominance in abundance analysis was based on 267 samples including 57158 individuals from both sampling methods since the dominance in biomass was based on 640 kg of fish only from gillnet sampling. In total was sampled 40 fish species, while catch statistics recorded 10 commercial species plus more 3 categories that include more other different species. In the sampling analysis, the most frequent species (very frequent were perch, bleak, roach, rudd and white bream. The most abundant(eudominant and dominant species were bleak, roach, rudd, perch, and white bream. In biomass dominate (eudominant and dominant roach, rudd, perch, white bream, bleak, gibel carp and pike. This analysis shows that Danube delta lakes are dominate by small eurytopic and opportunistic species, favoured by eutrophication of lakes. However, this figure is expression of sampling methods that are limited in estimation of real fish population status. Nevertheless, when this structure is compared to commercial statistics, it is noticed completely other figure. The difference in fish structure may be explained by targeting fishing to large size and high market value fish species. It is not neglected that commercial statistics is deformed by unreported catch sold on black market. According with recorded statistics from 1920 until 2010 the catch trend continuously decrease and species composition was well balanced before

$\\delta$-Expansion at Finite Temperature

OpenAIRE

Ramos, Rudnei O.

1996-01-01

We apply the $\\delta$-expansion perturbation scheme to the $\\lambda \\phi^{4}$ self-interacting scalar field theory in 3+1 D at finite temperature. In the $\\delta$-expansion the interaction term is written as $\\lambda (\\phi^{2})^{ 1 + \\delta}$ and $\\delta$ is considered as the perturbation parameter. We compute within this perturbative approach the renormalized mass at finite temperature at a finite order in $\\delta$. The results are compared with the usual loop-expansion at finite temperature.

A Delta-Sigma beamformer with integrated apodization

DEFF Research Database (Denmark)

Tomov, Borislav Gueorguiev; Stuart, Matthias Bo; Hemmsen, Martin Christian

2013-01-01

This paper presents a new design of a discrete time Delta-Sigma (ΔΣ) oversampled ultrasound beamformer which integrates individual channel apodization by means of variable feedback voltage in the Delta-Sigma analog to digital (A/D) converters. The output bit-width of each oversampled A/D converter...... remains the same as in an unmodified one. The outputs of all receiving channels are delayed and summed, and the resulting multi-bit sample stream is filtered and decimated to become an image line. The simplicity of this beamformer allows the production of high-channel-count or very compact beamformers....... The data are acquired using 12-bit flash A/D converters at a sampling rate of 70 MHz, and are then upsampled off-line to 560 MHz for input to the simulated ΔΣ beamformer. The latter generates a B-mode image which is compared to that produced by a digital beamformer that uses 10-bit A/D converters...

Variation in leaf water delta D and delta 18O values during the evapotranspiration process

International Nuclear Information System (INIS)

Leopoldo, P.R.; Foloni, L.L.

1984-01-01

A theoretical model was developed to evaluate leaf water delta D and delta 18 O variation in relation to: leaf temperature, relative humidity converted to leaf temperature and delta D and delta 18 O values of atmospheric water vapour and soil water. (M.A.C.) [pt

Rise and Fall of one of World's largest deltas; the Mekong delta in Vietnam

Science.gov (United States)

Minderhoud, P. S. J.; Eslami Arab, S.; Pham, H. V.; Erkens, G.; van der Vegt, M.; Oude Essink, G.; Stouthamer, E.; Hoekstra, P.

2017-12-01

The Mekong delta is the third's largest delta in the world. It is home to almost 20 million people and an important region for the food security in South East Asia. As most deltas, the Mekong delta is the dynamic result of a balance of sediment supply, sea level rise and subsidence, hosting a system of fresh and salt water dynamics. Ongoing urbanization, industrialization and intensification of agricultural practices in the delta, during the past decades, resulted in growing domestic, agricultural and industrial demands, and have led to a dramatic increase of fresh water use. Since the year 2000, the amount of fresh groundwater extracted from the subsurface increased by 500%. This accelerated delta subsidence as the groundwater system compacts, with current sinking rates exceeding global sea level rise up to an order of magnitude. These high sinking rates have greatly altered the sediment budget of the delta and, with over 50% of the Mekong delta surface elevated less than 1 meter above sea level, greatly increase vulnerability to flooding and storm surges and ultimately, permanent inundation. Furthermore, as the increasingly larger extractions rapidly reduce the fresh groundwater reserves, groundwater salinization subsequently increases. On top of that, dry season low-flows by the Mekong river cause record salt water intrusion in the delta's estuarine system, creating major problems for rice irrigation. We present the work of three years research by the Dutch-Vietnamese `Rise and Fall' project on land subsidence and salinization in both groundwater and surface water in the Vietnamese Mekong delta.

Losing ground in mega-deltas: basin-scale response to existential threats to the Mekong Delta

Science.gov (United States)

Arias, M. E.; Kondolf, G. M.; Schmitt, R. J. P.; Carling, P. A.; Darby, S. E.; Bizzi, S.; Castelletti, A.; Cochrane, T. A.; Gibson, S.; Kummu, M.; Oeurng, C.; Rubin, Z.; Wild, T. B.

2017-12-01

The Mekong Delta is, in terms of the number of livelihoods it supports, its economic importance, and in its vulnerability to climate change and sinking lands, one of the world's critically threatened mega-deltas. Livelihoods depend on the mere existence of the delta, but also on ecosystem services provided by the delta's drainage basin spanning 795,000 km2 in six abutting countries. These ecosystem services include delivery of sand required to build delta land in the face of rising sea-levels and sediment bound nutrients, provision of spawning habitat for fish that are ultimately harvested in the delta, and hydrologic regulation driving the delta's unique flood-pulse regime. However, while the delta is mainly located in Vietnam, the basin of the Mekong River is shared among China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. In the context of the region's dynamic growth, individual countries are pushing their own development agendas, which include extensive dam building, in-channel sand mining, construction of dykes and canals, and groundwater pumping, all of which contribute to subsidence and erosion of the Delta. Our synthesis of recent research indicates that most of the Mekong's delta land will likely fall below sea-level by 2100 as result of these drivers, exacerbating the impacts of global climatic changes. In this context, local infrastructural projects and changes in land- and water-management may temporarily mitigate some negative effects, but do not address the existential threat to the delta as a whole. To prevent, or at least substantially postpone, the drowning of the Mekong Delta requires identification of the key drivers and immediate concerted management actions on the basin-scale to change the trajectory of subsidence and sediment deficit. A specific challenge is to find the institutional arrangements in this transnational context that could support the needed management changes and equitably distribute costs and impacts. The Mekong Delta is

Modern sedimentation and morphology of the subaqueous Mekong Delta, Southern Vietnam

Science.gov (United States)

Unverricht, Daniel; Szczuciński, Witold; Stattegger, Karl; Jagodziński, Robert; Le, Xuan Thuyen; Kwong, Laval Liong Wee

2013-11-01

The Mekong River Delta is among the Asian mega-deltas and is influenced by various factors including tides (meso-tidal system), waves, coastal currents, monsoon-driven river discharge and human impact (agriculture, fishing, sand dredging, tourism). The present study aims to document the seafloor relief, sediment distribution and sediment accumulation rates to interpret modern sediment transport directions and main sedimentation processes in the subaqueous Mekong Delta. The major results of this investigation include the detection of two delta fronts 200 km apart, one at the mouth of the Bassac River (the biggest branch of the Mekong Delta) and the other around Cape Ca Mau (most south-western end of the Mekong Delta). Additionally, a large channel system runs in the subaqueous delta platform parallel to the shore and between the two fronts. The sediment accumulation rates vary greatly according to the location in the subaqueous delta and have reached up to 10 cm/yr for the last century. A cluster analysis of surface sediment samples revealed two different sediment types within the delta including a well-sorted sandy sediment and a poorly sorted, silty sediment. In addition, a third end member with medium to coarse sand characterised the distant parts of the delta at the transition to the open shelf. The increase of organic matter and carbonate content to the bottom set area and other sedimentary features such as shell fragments, foraminiferas and concretions of palaeo-soils that do not occur in delta sediments, supported grain size-based classification. Beginning in front of the Bassac River mouth, sedimentary pattern indicates clockwise sediment transport alongshore in the western direction to a broad topset area and the delta front around Cape Ca Mau. Our results clearly show the large lateral variability of the subaqueous Mekong Delta that is further complicated by strong monsoon-driven seasonality. River, tidal and wave forcing vary at local and seasonal scales

Hepatitis delta genotypes in chronic delta infection in the northeast of Spain (Catalonia).

Science.gov (United States)

Cotrina, M; Buti, M; Jardi, R; Quer, J; Rodriguez, F; Pascual, C; Esteban, R; Guardia, J

1998-06-01

Based on genetic analysis of variants obtained around the world, three genotypes of the hepatitis delta virus have been defined. Hepatitis delta virus variants have been associated with different disease patterns and geographic distributions. To determine the prevalence of hepatitis delta virus genotypes in the northeast of Spain (Catalonia) and the correlation with transmission routes and clinical disease, we studied the nucleotide divergence of the consensus sequence of HDV RNA obtained from 33 patients with chronic delta hepatitis (24 were intravenous drug users and nine had no risk factors), and four patients with acute self-limited delta infection. Serum HDV RNA was amplified by the polymerase chain reaction technique and a fragment of 350 nucleotides (nt 910 to 1259) was directly sequenced. Genetic analysis of the nucleotide consensus sequence obtained showed a high degree of conservation among sequences (93% of mean). Comparison of these sequences with those derived from different geographic areas and pertaining to genotypes I, II and III, showed a mean sequence identity of 92% with genotype I, 73% with genotype II and 61% with genotype III. At the amino acid level (aa 115 to 214), the mean identity was 87% with genotype I, 63% with genotype II and 56% with genotype III. Conserved regions included the RNA editing domain, the carboxyl terminal 19 amino acids of the hepatitis delta antigen and the polyadenylation signal of the viral mRNA. Hepatitis delta virus isolates in the northeast of Spain are exclusively genotype I, independently of the transmission route and the type of infection. No hepatitis delta virus subgenotypes were found, suggesting that the origin of hepatitis delta virus infection in our geographical area is homogeneous.

A 1microW 85nV/ radicalHz pseudo open-loop preamplifier with programmable band-pass filter for neural interface system.

Science.gov (United States)

Chang, Sun-Il; Yoon, Euisik

2009-01-01

We report an energy efficient pseudo open-loop amplifier with programmable band-pass filter developed for neural interface systems. The proposed amplifier consumes 400nA at 2.5V power supply. The measured thermal noise level is 85nV/ radicalHz and input-referred noise is 1.69microV(rms) from 0.3Hz to 1 kHz. The amplifier has a noise efficiency factor of 2.43, the lowest in the differential topologies reported up to date to our knowledge. By programming the switched-capacitor frequency and bias current, we could control the bandwidth of the preamplifier from 138 mHz to 2.2 kHz to meet various application requirements. The entire preamplifier including band-pass filters has been realized in a small area of 0.043mm(2) using a 0.25microm CMOS technology.

Deltas on the move. Making deltas cope with the effects of climate change

International Nuclear Information System (INIS)

Reker, J.; Van Winden, A.; Braakhekke, W.; Vermaat, J.; Eleveld, M.; Janssen, R.; De Reus, N.; Omzigt, N.

2006-01-01

This scoping study is the first phase of a study aimed at: (a) providing knowledge on the potential of a system-based approach to deal with the effects of climate change as an alternative for the more traditional technical measures such as dams, dikes and surge barriers. This should be shown for both rich and poor countries and should address hydrological, ecological as well as socio-economic aspects; and (b) identifying the potential to market these results worldwide. To reach these objectives four research steps are defined: (1) to make an inventory of deltas: their vulnerability to the effects of climate change; (2) development of indicators for successful use of a system-based approach; (3) to provide an overview of the potential of soft measures for these deltas; (4) to select a number of deltas with potential for marketing system-based measures and the development of strategies to link economic and ecological objectives. This scoping study addresses step 1 only. The results from step 1 will be used as a starting point for steps 2 and 3. The outputs of this scoping study are threefold: a background report (this report); a flyer with a brief description of the findings; a website with information on delta's and how these may be affected by climate change. The scoping study will roughly outline which deltas are still functioning in a more or less natural manner - or could be (re)developed in that direction - and thus would be good candidates for a system-based approach. Chapter 2 gives a description of the geomorphological and ecological processes in a delta. In addition, those aspects of climate change that can have an effect on deltas are described. The third chapter deals with human interventions in deltas and whether or not they fit within a system-based approach. In a system-based approach, as presented in Chapter 4, natural processes are given free reign where possible. Chapter 5 shows how available data on deltas could be used in such a system

Isotopic variations ({delta}{sup 13} C and {delta}{sup 18} O) in Siderastrea stellata (Cnidaria-Anthozoa), Itamaraca island, State of Pernambuco, Northeastern Brazil

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Valderez P.; Sial, Alcides N. [Pernambuco Univ., Recife, PE (Brazil). Dept. de Geologia. Lab. de Isotopos Estaveis; Mayeal, Elga M.; Exner, Marco Antonio [Pernambuco Univ., Recife, PE (Brazil). Dept. de Zoologia. Lab. de Macro e Megabentos

1998-12-01

Isotopic determinations for O and C were performed in coral skeletons collected in beach rocks from two localities (Orange and Catuama), Itamaraca Island, north littoral of the State of pernambuco, northeastern Brazil. Large variations of {delta}{sup 18} O and {delta}{sup 13} C in corals from both localities are found, the largest ones being observed at the Orange locality {delta}{sup 13} C in this locality varies from -0.8 to +1.8% PDB and {delta}{sup 1.8} O from -5.3 to -1.8% PDB, while at the Catuama locality, they vary from -1.8 to 0.1% PDB and -3.8 to -2.7% PDB, respectively. Large variations in {delta}{sup 18} O (up to 2.5%) coupled with weakly defined positive correlation between {delta}{sup 18} O and {delta}{sup 13} C, can be attributed to temperature variations as consequence of climatic perturbations. Temperature estimates, calculated from {delta}{sup 18} O values, assuming isotopic equilibrium with seawater, yield values between 24.9 deg C and 43.1 deg C at Orange, and from 28.4 deg C to 35 deg C at Catuama, all of them (expect one growth band from one sample) are high enough for the full development of the coral colony. Temperature average is 31.4 deg C at Orange, which is a little bit higher than that at Catuama, but both of them indicate thermal stress conditions. In all analyzed specimens, expect for one, at Orange, T increases was accompanied by decreasing in the organic activity, as suggested by corresponding negative {delta}{sup 13} C anomaly. Therefore, the observed bleaching is possibly related to thermal stress and the high T may be related to the El Nino-Southern Oscillation (ENSO) warning event. On the other hand, anthropogenic action at Orange, local of intense tourism throughout the year, coupled with high rate of sedimentation in the region, may contribute to the observed coral bleaching. (author)

Tides Stabilize Deltas until Humans Interfere

Science.gov (United States)

Hoitink, T.; Zheng Bing, W.; Vermeulen, B.; Huismans, Y.; Kastner, K.

2017-12-01

Despite global concerns about river delta degradation caused by extraction of natural resources, sediment retention by reservoirs and sea-level rise, human activity in the world's largest deltas intensifies. In this review, we argue that tides tend to stabilize deltas until humans interfere. Under natural circumstances, delta channels subject to tides are more stable than their fluvial-dominated counterparts. The oscillatory tidal flow counteracts the processes responsible for bank erosion, which explains why unprotected tidal channels migrate only slowly. Peak river discharges attenuate the tides, which creates storage space to accommodate the extra river discharge during extreme events and as a consequence, reduce flood risk. With stronger tides, the river discharge is being distributed more evenly over the various branches in a delta, preventing silting up of smaller channels. Human interference in deltas is massive. Storm surge barriers are constructed, new land is being reclaimed and large-scale sand excavation takes place, to collect building material. Evidence from deltas around the globe shows that in human-controlled deltas the tidal motion often plays a destabilizing role. In channels of the Rhine-Meuse Delta, some 100 scour holes are identified, which relates to the altered tidal motion after completion of a storm surge barrier. Sand mining has led to widespread river bank failures in the tidally-influenced Mekong Delta. The catastrophic flood event in the Gauges-Brahmaputra Delta by Cyclone Aila, which caused the inundation of an embanked polder area for over two years, was preceded by river bank erosion at the mouths of formal tidal channels that were blocked by the embankment. Efforts to predict the developments of degrading deltas are few. Existing delta models are capable of reproducing expanding deltas, which is essentially a matter of simulating the transport of sediment from source in a catchment to the sink in a delta. Processes of soil

Acid Rain in Niger Delta Region: Implication on Water Resources ...

African Journals Online (AJOL)

This research focused on the effect of acid rain on the water quality of the Niger Delta region of Nigeria. Three hundred water samples were collected: 100 water samples from rain, 100 from open wells and 100 from rivers. The water samples were analysed using the paired t-test and multiple correlation analysis to ascertain ...

In vivo metabolism of the methyl homologues of delta-8-tetrahydrocannabinol, delta-9-tetrahydrocannabinol and abn-delta-8-tetrahydrocannabinol in the mouse.

Science.gov (United States)

Brown, N K; Harvey, D J

1988-04-01

Methyl-delta-8-tetrahydrocannabinol (methyl-delta-8-THC), methyl-delta-9-THC and abn-methyl-delta-8-THC were synthesized by condensation of orcinol and (1S)-cis-verbenol and were administered to male Charles River CD-1 mice. Extracted hepatic metabolites were isolated by chromatography on Sephadex LH-20 and examined by gas chromatography/mass spectrometry as trimethylsilyl (TMS), (2H9)TMS and methyl ester/TMS derivatives. In addition, metabolic fractions were reduced with lithium aluminium deuteride to convert carboxylic acids to alcohols for structural correlation. Metabolites from methyl-delta-8-THC were similar with respect to the positions substituted to those produced by higher homologues; the major metabolite was methyl-delta-8-THC-11-oic acid. abn-Methyl-delta-8-THC was metabolized in a different manner. The location of the aromatic methyl group at the position adjacent to ring fusion appeared to inhibit metabolism at C(11) to a considerable extent and also to reduce the amount of the resulting alcohol from being oxidized to a carboxylic acid. This caused other metabolic pathways to become dominant, with the result that a compound containing a hydroxy group at the gem-methyl position was the major metabolite. Hydroxylation at this position has not been confirmed with any other cannabinoid, although it is thought to result in trace concentrations of hydroxy metabolites from some compounds. Metabolism of methyl-delta-9-THC was also similar to that of the higher homologues, with the exception that less metabolism occurred at C(8) and a higher percentage of the total metabolic fraction was accounted for by the 11-oic acid metabolite. Minor metabolites were mainly dihydroxy compounds and hydroxylated derivatives of delta-9-THC-11-oic acid.

Rarotonga Radiocarbon (delta 14C) for 1950 to 1997

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Rarotonga coral radiocarbon (14C) timeseries. Coral radiocarbon (Delta-14C) on untreated, low-speed drilled samples. Precision is +/- 4 per mil as documented by an...

Generalized predictive control in the delta-domain

DEFF Research Database (Denmark)

Lauritsen, Morten Bach; Jensen, Morten Rostgaard; Poulsen, Niels Kjølstad

1995-01-01

This paper describes new approaches to generalized predictive control formulated in the delta (δ) domain. A new δ-domain version of the continuous-time emulator-based predictor is presented. It produces the optimal estimate in the deterministic case whenever the predictor order is chosen greater...... than or equal to the number of future predicted samples, however a “good” estimate is usually obtained in a much longer range of samples. This is particularly advantageous at fast sampling rates where a “conventional” predictor is bound to become very computationally demanding. Two controllers...

Magneto-optical spectroscopy of diluted magnetic oxides TiO{sub 2-{delta}}: Co

Energy Technology Data Exchange (ETDEWEB)

Gan' shina, E.A. [Faculty of Physics, Moscow State M.V. Lomonosov University, Moscow 119991 (Russian Federation)], E-mail: Eagan@magn.ru; Granovsky, A.B. [Faculty of Physics, Moscow State M.V. Lomonosov University, Moscow 119991 (Russian Federation); Orlov, A.F. [State Research Institute for the Rare-Metal Industry, Moscow 119017 (Russian Federation); Perov, N.S.; Vashuk, M.V. [Faculty of Physics, Moscow State M.V. Lomonosov University, Moscow 119991 (Russian Federation)

2009-04-15

We report an experimental study on transversal Kerr effect (TKE) in magnetic oxide semiconductors TiO{sub 2-{delta}}:Co. The TiO{sub 2-{delta}}: Co thin films were deposited on LaAlO{sub 3} (0 0 1) substrates by magnetron sputtering in the argon-oxygen atmosphere at oxygen partial pressure of 2x10{sup -6}-2x10{sup -4} Torr. It was obtained that TKE spectra in ferromagnetic samples are extremely sensitive to the Co-volume fraction, the crystalline structure, and technology parameters. The observed well-pronounced peaks in TKE spectra for anatase Co-doped TiO{sub 2-{delta}} films at low Co (<1%) volume fraction are not representative for bulk Co or Co clusters in TiO{sub 2-{delta}} matrix that indicates on intrinsic ferromagnetism in these samples. With increase of Co-volume fraction up to 5-8% the fine structure of TKE spectra disappears and magneto-optical response in reflection mode becomes larger than that for thick Co films.

Detecting and Characterizing Exoplanets with the WFIRST Coronagraph: Colors of Planets in Standard and Designer Bandpasses-SETI

Science.gov (United States)

Turnbull, Margaret

The WFIRST mission is now envisioned to include a coronagraph for the purpose of direct detection of nearby exoplanets, including planets known to exist via radial velocity detection and new discoveries. Assuming that starlight rejection sufficient for planet detection (~1e-9) can be achieved, what can be learned about these planets given a realistic spectral resolution and signal-to-noise ratio? We propose to investigate the potential for WFIRST to efficiently discriminate planets from background sources, and to characterize planets in terms of important diagnostic atmospheric features, using broad- and intermediate band color data. We will map out this capability as a function of signal-to-noise ratio, bandpass location, and bandpass width. Our investigation will place emphasis on gas giants, ice giants, and mini-Neptunes (compatible with current AFTA-C baseline performance specifications), as well as a variety of super-Earths (an AFTA-C "stretch" goal). We will explore a variety of compositions, cloud types, phase angles, and (in the case of super-Earths with semi-transparent atmospheres) surface types. Noiseless spectra generated for these model planets will be passed through (a) standard bandpasses for comparison to prior work and (b) filter transmission curves corresponding to bandpasses of 5-20% over the full range of WFIRST's expected bandpass (400 - 1,000 nm). From this, filter combinations will be used to generate planet colors and find filter sets that most efficiently discriminate between planets and background sources, and between planets of different type. We will then repeat this exercise for S/N levels of 1-1,000 in order to (1) explore the true efficacy of broadband measurements in exoplanet studies, and (2) provide an estimate of total required integration time for a compelling WFIRST exoplanet program. To accomplish this, we will use model spectra for mini-Neptunes, and ice and gas giants of varying composition (Hu et al. 2013), and observed

Phenotypic expressions of CCR5-Delta 32/Delta 32 homozygosity

NARCIS (Netherlands)

Nguyen, GT; Carrington, M; Beeler, JA; Dean, M; Aledort, LM; Blatt, PM; Cohen, AR; DiMichele, D; Eyster, ME; Kessler, CM; Konkle, B; Leissinger, C; Luban, N; O'Brien, SJ; Goedert, JJ; O'Brien, TR

1999-01-01

Objective: As blockade of CC-chemokine receptor 5 (CCR5) has been proposed as therapy for HIV-1, we examined whether the CCR5-Delta 32/Delta 32 homozygous genotype has phenotypic expressions other than those related to HIV-1. Design: Study subjects were white homosexual men or men with hemophilia

Contaminant Effects on California Bay–Delta Species and Human Health

Directory of Open Access Journals (Sweden)

Stephanie Fong

2016-12-01

Full Text Available doi: https://doi.org/10.15447/sfews.2016v14iss4art5Many contaminants in the California Bay–Delta (Bay–Delta exceed regulatory standards, affect aquatic species, and potentially affect human health. Recent studies provide multiple lines of evidence that contaminants affect species of concern in the Bay–Delta (e.g., the decline of several important fish species referred to as the “Pelagic Organism Decline” or POD. Contaminants occur as dynamic complex mixtures and exert effects at multiple levels of biological organization. Multiple chemicals impair processes at cellular and physiological levels (measured as growth, development, and behavior abnormalities, and when viability and reproductive output are affected, populations are affected. As an important example, the population decline of the endangered Delta Smelt (Hypomesus transpacificus is significantly associated with multiple stressors, including insecticide use. New analyses presented in this paper show significant correlations between pyrethroid use and declining abundance of POD fish species. Water sampled from the Bay–Delta causes multiple deleterious effects in fish, and Delta Smelt collected from the Bay–Delta exhibit contaminant effects. Fish prey items are also affected by contaminants; this may have an indirect effect on their populations. Co-occurrence with thermal changes or disease can exacerbate contaminant effects. Contaminants also pose threats to human health via consumption of fish and shellfish, drinking water, and contact recreation, in particular, mercury, cyanobacteria toxins, disinfection byproducts, pathogens, pesticides, and pharmaceuticals and personal care products. The role of contaminants in the decline of Bay–Delta species is difficult to accurately assess in a complex, dynamic system. However, tools and approaches are available to evaluate contaminant effects on Bay–Delta species, and separate the effects of multiple stressors. Integrated

Migration in Deltas: An Integrated Analysis

Science.gov (United States)

Nicholls, Robert J.; Hutton, Craig W.; Lazar, Attila; Adger, W. Neil; Allan, Andrew; Arto, Inaki; Vincent, Katharine; Rahman, Munsur; Salehin, Mashfiqus; Sugata, Hazra; Ghosh, Tuhin; Codjoe, Sam; Appeaning-Addo, Kwasi

2017-04-01

Deltas and low-lying coastal regions have long been perceived as vulnerable to global sea-level rise, with the potential for mass displacement of exposed populations. The assumption of mass displacement of populations in deltas requires a comprehensive reassessment in the light of present and future migration in deltas, including the potential role of adaptation to influence these decisions. At present, deltas are subject to multiple drivers of environmental change and often have high population densities as they are accessible and productive ecosystems. Climate change, catchment management, subsidence and land cover change drive environmental change across all deltas. Populations in deltas are also highly mobile, with significant urbanization trends and the growth of large cities and mega-cities within or adjacent to deltas across Asia and Africa. Such migration is driven primarily by economic opportunity, yet environmental change in general, and climate change in particular, are likely to play an increasing direct and indirect role in future migration trends. The policy challenges centre on the role of migration within regional adaptation strategies to climate change; the protection of vulnerable populations; and the future of urban settlements within deltas. This paper reviews current knowledge on migration and adaptation to environmental change to discern specific issues pertinent to delta regions. It develops a new integrated methodology to assess present and future migration in deltas using the Volta delta in Ghana, Mahanadi delta in India and Ganges-Brahmaputra-Meghna delta across India and Bangladesh. The integrated method focuses on: biophysical changes and spatial distribution of vulnerability; demographic changes and migration decision-making using multiple methods and data; macro-economic trends and scenarios in the deltas; and the policies and governance structures that constrain and enable adaptation. The analysis is facilitated by a range of

Equilibrium state of delta-phase with tellurium in the Sb-Bi-Te system

International Nuclear Information System (INIS)

Gajgukova, V.S.; Dudkin, L.D.; Erofeev, R.S.; Musaelyan, V.V.; Nadzhip, A.Eh.; Sokolov, O.B.

1978-01-01

A research has been carried out with a view to establish the equilibrium state of delta-phase of the composition (Sbsub(1-x)Bisub(x)) 2 Te 3 with tellurium, depending on x and temperature. The Hall effect, the thermoelectromotive force, and the electric conductivity of the samples of Sb-Bi-Te alloys have been measured, the samples being annealed at various temperatures (550 to 250 deg C). The measurement results have shown that as the Bi 2 Te 3 content in the solid solutions increases and temperature decreases, the delta-phase-Te boundary monotonously approaches the stoichiometric composition. Using the research carrid out as the basis, the general character of the equilibrium delta-phase with tellurium boundary has been rendered more precise in Sb-Bi-Te system, depending on the temperature and Bi content (up to 25 at.%)

Mystery of the delta(980)

International Nuclear Information System (INIS)

Cahn, R.N.; Landshoff, P.V.

1986-01-01

The apparent conflict between the dominance of the decay delta->etaπ in D->deltaπ and its absence in iota->deltaπ is analyzed. Explicit models are presented in which the nearby Kanti K threshold plays an important role in resolving the conflict. (orig.)

Niger Delta Development Commission and Sustainable ...

African Journals Online (AJOL)

Niger Delta Development Commission and Sustainable Development of Niger Delta Region of Nigeria: The Case of Rivers State. Goddey Wilson. Abstract. The study is on Niger Delta Development Commission and sustainable development of Niger Delta region of Nigeria, the case of Rivers State. The main objective of the ...

Large old trees influence patterns of delta13C and delta15N in forests.

Science.gov (United States)

Weber, Pascale; Bol, Roland; Dixon, Liz; Bardgett, Richard D

2008-06-01

Large old trees are the dominant primary producers of native pine forest, but their influence on spatial patterns of soil properties and potential feedback to tree regeneration in their neighbourhood is poorly understood. We measured stable isotopes of carbon (delta(13)C) and nitrogen (delta(15)N) in soil and litter taken from three zones of influence (inner, middle and outer zone) around the trunk of freestanding old Scots pine (Pinus sylvestris L.) trees, to determine the trees' influence on below-ground properties. We also measured delta(15)N and delta(13)C in wood cores extracted from the old trees and from regenerating trees growing within their three zones of influence. We found a significant and positive gradient in soil delta(15)N from the inner zone, nearest to the tree centre, to the outer zone beyond the tree crown. This was probably caused by the higher input of (15)N-depleted litter below the tree crown. In contrast, the soil delta(13)C did not change along the gradient of tree influence. Distance-related trends, although weak, were visible in the wood delta(15)N and delta(13)C of regenerating trees. Moreover, the wood delta(15)N of small trees showed a weak negative relationship with soil N content in the relevant zone of influence. Our results indicate that large old trees control below-ground conditions in their immediate surroundings, and that stable isotopes might act as markers for the spatial and temporal extent of these below-ground effects. John Wiley & Sons, Ltd

An analytical framework for strategic delta planning : negotiating consent for long-term sustainable delta development

NARCIS (Netherlands)

Seijger, C.; Douven, W; Hermans, L.M.; Evers, J.; Phi, H. L.; Brunner, J.; Pols, L.; Ligtvoet, W.; Koole, S.; Slager, K.; Vermoolen, M.S.; Hasan, S.; Hoang, V. T M; van Halsema, G

2016-01-01

Sectoral planning on water, agriculture and urban development has not been able to prevent increased flood risks and environmental degradation in many deltas. Governments conceive strategic delta planning as a promising planning approach and develop strategic delta plans. Such plans are linked to

Design of a Balun Bandpass Filter with Asymmetrical Coupled Microstrip Lines

Science.gov (United States)

Wang, Xuedao; Wang, Jianpeng; Zhang, Gang; Huang, Feng

2017-07-01

A new microstrip coupled-line balun topology and its application to the balun bandpass filter (BPF) with a triple mode response are proposed in this paper. The involved balun structure is composed of two back-to-back quarter-wavelength (λ/4) asymmetrical coupled-line sections. Detailed design formulas based on the asymmetrical coupled-line theory are given to validate the feasibility of the balun. Besides, to obtain filtering performance simultaneously, the balun is then effectively integrated with a pair of triple mode resonators. To demonstrate the design concept of the balun BPF, a prototype operating at 2.4 GHz with the fractional bandwidth (FBW) of about 19.2 % is designed, fabricated, and measured. Results indicate that between the two balanced outputs, the amplitude imbalance is less than 0.3 dB and the phase difference is within 180°±5° inside the whole passband. Both simulated and experimental results are in good agreement.

Catalyzing action towards the sustainability of deltas: deltas as integrated socio-ecological systems and sentinels of regional and global change

Science.gov (United States)

Foufoula-Georgiou, E.; Tessler, Z. D.; Brondizio, E.; Overeem, I.; Renaud, F.; Sebesvari, Z.; Nicholls, R. J.; Anthony, E.

2016-12-01

Deltas are highly dynamic and productive environments: they are food baskets of the world, home to biodiverse and rich ecosystems, and they play a central role in food and water security. However, they are becoming increasingly vulnerable to risks arising from human activities, land subsidence, regional water management, global sea-level rise, and climate extremes. Our Belmont Forum DELTAS project (BF-DELTAS: Catalyzing actions towards delta sustainability) encompasses an international network of interdisciplinary research collaborators with focal areas in the Mekong, Ganges Brahmaputra, and the Amazon deltas. The project is organized around five main modules: (1) developing an analytical framework for assessing delta vulnerability and scenarios of change (Delta-SRES), (2) developing an open-acess, science-based integrative modeling framework for risk assessment and decision support (Delta-RADS), (3) developing tools to support quantitative mapping of the bio-physical and socio-economic environments of deltas and consolidate bio-physical and social data within shared data repositories (Delta-DAT), (4) developing Global Delta Vulnerability Indices (Delta-GDVI) that capture current and projected scenarios for major deltas around the world , and (5) collaborating with regional stakeholders to put the science, modeling, and data into action (Delta-ACT). In this talk, a research summary will be presented on three research domains around which significant collaborative work was developed: advancing biophysical classification of deltas, understanding deltas as coupled socio-ecological systems, and analyzing and informing social and environmental vulnerabilities in delta regions.

{delta}{sup 13}C in Tibetan juniper trees - climate trends through the past 1600 years; {delta}{sup 13}C in tibetischen Wacholdern - Klimaentwicklung der letzten 1600 Jahre

Energy Technology Data Exchange (ETDEWEB)

Zimmermann, B.

1998-09-01

A {delta}{sup 13}C{sub Zell}-chronology of juniper tree cellulose from the upper treeline covering the last 1600 years was set up. The tree site is situated close to Qamdo in southeast Tibet at an altitude of 4350 m a.s.l. The southwest slope gets rain during the Indian summer monsoon. Ten trees have been sampled either by coring or by cutting of trunc-sections in pentad sampling interval. Three trees were analysed in two different radial directions. The very positive {delta}{sup 13}C{sub Zell}-data generally varying around -18,75 permille show the typical low fractionation of high mountain plants. Different interpretations are suggested for data before and after 1800 A.D. (orig.) [Deutsch] An Zellulose von Wacholdern der oberen Waldgrenze in Suedost-Tibet wurde eine 1600-jaehrige {delta}{sup 13}C{sub Zell}-Chronologie aufgestellt. Der Standort liegt in 4350 m ue.M. in der Naehe von Qamdo, ist nach Suedwest geneigt und erhaelt Niederschlaege in den Sommermonaten durch den Indischen-Suedwest-Monsun. Zehn Baeume wurden anhand von Kernen und Stammscheiben in Abschnitten von fuenf Jahren beprobt. An drei Baeumen konnten zwei Segmente desselben Baumes untersucht werden. Die im Mittel sehr positiven {delta}{sup 13}C{sub Zell}-Daten um -18,75 permille deuten auf eine fuer Hochgebirgspflanzen typische geringere Fraktionierung hin. Unterschiedliche Interpretationswege werden fuer die Daten vor und nach 1800 verfolgt. (orig.)

The geographic spread of the CCR5 Delta32 HIV-resistance allele.

Directory of Open Access Journals (Sweden)

John Novembre

2005-11-01

Full Text Available The Delta32 mutation at the CCR5 locus is a well-studied example of natural selection acting in humans. The mutation is found principally in Europe and western Asia, with higher frequencies generally in the north. Homozygous carriers of the Delta32 mutation are resistant to HIV-1 infection because the mutation prevents functional expression of the CCR5 chemokine receptor normally used by HIV-1 to enter CD4+ T cells. HIV has emerged only recently, but population genetic data strongly suggest Delta32 has been under intense selection for much of its evolutionary history. To understand how selection and dispersal have interacted during the history of the Delta32 allele, we implemented a spatially explicit model of the spread of Delta32. The model includes the effects of sampling, which we show can give rise to local peaks in observed allele frequencies. In addition, we show that with modest gradients in selection intensity, the origin of the Delta32 allele may be relatively far from the current areas of highest allele frequency. The geographic distribution of the Delta32 allele is consistent with previous reports of a strong selective advantage (>10% for Delta32 carriers and of dispersal over relatively long distances (>100 km/generation. When selection is assumed to be uniform across Europe and western Asia, we find support for a northern European origin and long-range dispersal consistent with the Viking-mediated dispersal of Delta32 proposed by G. Lucotte and G. Mercier. However, when we allow for gradients in selection intensity, we estimate the origin to be outside of northern Europe and selection intensities to be strongest in the northwest. Our results describe the evolutionary history of the Delta32 allele and establish a general methodology for studying the geographic distribution of selected alleles.

A Hybrid Circuit for Spoof Surface Plasmons and Spatial Waveguide Modes to Reach Controllable Band-Pass Filters.

Science.gov (United States)

Zhang, Qian; Zhang, Hao Chi; Wu, Han; Cui, Tie Jun

2015-11-10

We propose a hybrid circuit for spoof surface plasmon polaritons (SPPs) and spatial waveguide modes to develop new microwave devices. The hybrid circuit includes a spoof SPP waveguide made of two anti-symmetric corrugated metallic strips and a traditional substrate integrated waveguide (SIW). From dispersion relations, we show that the electromagnetic waves only can propagate through the hybrid circuit when the operating frequency is less than the cut-off frequency of the SPP waveguide and greater than the cut-off frequency of SIW, generating efficient band-pass filters. We demonstrate that the pass band is controllable in a large range by designing the geometrical parameters of SPP waveguide and SIW. Full-wave simulations are provided to show the large adjustability of filters, including ultra wideband and narrowband filters. We fabricate a sample of the new hybrid device in the microwave frequencies, and measurement results have excellent agreements to numerical simulations, demonstrating excellent filtering characteristics such as low loss, high efficiency, and good square ratio. The proposed hybrid circuit gives important potential to accelerate the development of plasmonic integrated functional devices and circuits in both microwave and terahertz frequencies.

Delta Morphodynamics Matters! Ecosystem Services, Poverty and Morphodynamic Change in the Ganges-Brahmaputra Mega-Delta

Science.gov (United States)

Nicholls, R. J.; Adger, N.; Allan, A.; Darby, S. E.; Hutton, C.; Matthews, Z.; Rahman, M.; Whitehead, P. G.; Wolf, J.

2013-12-01

The world's deltas are probably the most vulnerable type of coastal environment, and they face multiple stresses in the coming decades. These stresses include, amongst others, local drivers due to land subsidence, population growth and urbanisation within the deltas, regional drivers due to changes in catchment management (e.g. upstream land use and dam construction), as well as global climate change impacts such as sea-level rise. At the same time, the ecosystem services of river deltas support high population densities, with around 14% of the global population inhabiting deltas. A large proportion of these people experience extremes of poverty and they are therefore severely exposed to vulnerability from environmental and ecological stress and degradation. In areas close to or below the poverty boundary, both subsistence and cash elements of the economy tend to rely disproportionately heavily on ecosystem services which underpin livelihoods. Therefore, to sustainably manage delta environments they must be viewed as complex social-environmental systems where change is only partially driven by physical drivers such as sea level rise and climate change, and human-induced development activities are also critical. Here we outline a new conceptual framework for the development of methods to understand and characterise the key drivers of change in ecosystem services that affect the environment and economic status of populous deltas, focusing specifically on the Ganges-Brahmaputra-Meghna (GBM) mega-delta. The GBM delta is characterised by densely populated coastal lowlands with significant poverty, with livelihoods supported to a large extent by natural ecosystems such as the Sunderbahns (the largest mangrove forest in the world). However, the GBM delta is under severe development pressure due to many growing cities. At present the importance of ecosystems services to poverty and livelihoods is poorly understood. This is due to due to the complexity of interactions

Comparison of the difference and delta 15nitrogen approaches for evaluating liquid urea ammonium nitrate utilization by maize

International Nuclear Information System (INIS)

Clay, D.E.

1997-01-01

Isotopic nitrogen (N) research techniques may be required in watershed studies to determine the impact of landscape position on fertilizer efficiency and the soil supplying power. However, traditional approaches using 15N labeled fertilizer may not be suitable when farmer equipment is used. The delta 15N natural abundance isotopic approach has been used to evaluate N cycling in watersheds. The objectives of this study were to measure the precision of the delta 15N measurement by the Europa 20-20 ratio mass spectrometer (Europa Scientific Ltd, UK), and to compare the difference and delta 15N approaches for measuring fertilizer use by maize (Zea mays). A replicated field study containing two different N rates (0 and 15.7 g N m-2) were used for the study. Maize samples were collected at the 8th-leaf, silking, and plant maturity in 1992 and 1993. Samples were dried (80 degrees C), ground (1-mm), weighed (stover 12 mg and grain 3 mg), and analyzed for total N and delta 15N. Fertilizer utilization at the three growth stages was determined using the natural abundance delta 15N and nonisotopic difference (fertilizer-control) techniques. During the study, the Europa 20-20 ratio mass spectrometer (Europa Scientific Ltd, UK) analyzed over 100 samples a day and had consumable costs of less than $2.00 per sample. The standard deviations of the mean were less than 0.11 and 0.21 per thousand in 51 and 77% of the stover samples, respectively. In 1992, grain yields were not influenced by N fertilizer additions, while in 1993 grain yields were increased by N fertilizer. The difference method estimated that in 1992, 16% of the N fertilizer was utilized by the crop, while the natural abundance delta 15N approach estimated that 36% of the fertilizer N was used by the crop. Differences between calculated values by the two techniques resulted from the difference method calculating net fertilizer use, while the delta 15N approach calculated fertilizer contained in the plant

Hydrogeochemical and stream sediment reconnaissance basic data for Big Delta Quadrangle, Alaska

International Nuclear Information System (INIS)

1981-01-01

Field and laboratory data are presented for 1380 water samples from the Big Delta Quadrangle, Alaska. The samples were collected by Los Alamos Scientific Laboratory; laboratory analysis and data reporting were performed by the Uranium Resource Evaluation Project at Oak Ridge, Tennessee

Future Change to Tide-Influenced Deltas

Science.gov (United States)

Nienhuis, Jaap H.; Hoitink, A. J. F. (Ton); Törnqvist, Torbjörn E.

2018-04-01

Tides tend to widen deltaic channels and shape delta morphology. Here we present a predictive approach to assess a priori the effect of fluvial discharge and tides on deltaic channels. We show that downstream channel widening can be quantified by the ratio of the tide-driven discharge and the fluvial discharge, along with a second metric representing flow velocities. A test of our new theory on a selection of 72 deltas globally shows good correspondence to a wide range of environments, including wave-dominated deltas, river-dominated deltas, and alluvial estuaries. By quantitatively relating tides and fluvial discharge to delta morphology, we offer a first-order prediction of deltaic change that may be expected from altered delta hydrology. For example, we expect that reduced fluvial discharge in response to dam construction will lead to increased tidal intrusion followed by enhanced tide-driven sediment import into deltas, with implications for navigation and other human needs.

Identification of anthropogenic and natural inputs of sulfate and chloride into the karstic ground water of Guiyang, SW China: combined delta37Cl and delta34S approach.

Science.gov (United States)

Liu, Cong-Qiang; Lang, Yun-Chao; Satake, Hiroshi; Wu, Jiahong; Li, Si-Liang

2008-08-01

Because of active exchange between surface and groundwater of a karstic hydrological system, the groundwater of Guiyang, the capital city of Guizhou Province, southwest China, has been seriously polluted by anthropogenic inputs of NO3-, SO4(2-), Cl-, and Na+. In this work, delta37Cl of chloride and delta34S variations of sulfate in the karstic surface/groundwater system were studied, with a main focus to identify contaminant sources, including their origins. The surface, ground, rain, and sewage water studied showed variable delta37Cl and delta34S values, in the range of -4.1 to +2.0 per thousand, and -20.4 to +20.9 per thousand for delta37Cl and delta34S (SO4(2-)), respectively. The rainwater samples yielded the lowest delta37Cl values among those observed to date for aerosols and rainwater. Chloride in the Guiyang area rain waters emanated from anthropogenic sources rather than being of marine origin, probably derived from HCl (g) emitted by coal combustion. By plotting 1/SO4(2-) vs delta34S and 1/Cl- vs delta37Cl, respectively, we were able to identify some clusters of data, which were assigned as atmospheric deposition (acid rain component), discharge from municipal sewage, paleo-brine components in clastic sedimentary rocks, dissolution of gypsum mainly in dolomite, oxidation of sulfide minerals in coal-containing clastic rocks, and possibly degradation of chlorine-containing organic matter. We conclude that human activities give a significant input of sulfate and chloride ions, as well as other contaminants, into the studied groundwater system through enhanced atmospheric deposition and municipal sewage, and that multiple isotopic tracers constitute a powerful tool to ascertain geochemical characteristics and origin of complex contaminants in groundwater.

From Natural to Design River Deltas

Science.gov (United States)

Giosan, Liviu

2016-04-01

Productive and biologically diverse, deltaic lowlands attracted humans since prehistory and may have spurred the emergence of the first urban civilizations. Deltas continued to be an important nexus for economic development across the world and are currently home for over half a billion people. But recently, under the double whammy of sea level rise and inland sediment capture behind dams, they have become the most threatened coastal landscape. Here I will address several deceptively simple questions to sketch some unexpected answers using example deltas from across the world from the Arctic to the Tropics, from the Danube to the Indus, Mississippi to Godavari and Krishna, Mackenzie to Yukon. What is a river delta? What is natural and what is not in a river delta? Are the geological and human histories of a delta important for its current management? Is maintaining a delta the same to building a new one? Can we design better deltas than Nature? These answers help us see clearly that survival of deltas in the next century depends on human intervention and is neither assured nor simple to address or universally applicable. Empirical observations on the hydrology, geology, biology and biochemistry of deltas are significantly lagging behind modeling capabilities endangering the applicability of numerical-based reconstruction solutions and need to be ramped up significantly and rapidly across the world.

Covariance of bacterioplankton composition and environmental variables in a temperate delta system

Science.gov (United States)

Stepanauskas, R.; Moran, M.A.; Bergamaschi, B.A.; Hollibaugh, J.T.

2003-01-01

We examined seasonal and spatial variation in bacterioplankton composition in the Sacramento-San Joaquin River Delta (CA) using terminal restriction fragment length polymorphism (T-RFLP) analysis. Cloned 16S rRNA genes from this system were used for putative identification of taxa dominating the T-RFLP profiles. Both cloning and T-RFLP analysis indicated that Actinobacteria, Verrucomicrobia, Cytophaga-Flavobacterium and Proteobacteria were the most abundant bacterioplankton groups in the Delta. Despite the broad variety of sampled habitats (deep water channels, lakes, marshes, agricultural drains, freshwater and brackish areas), and the spatial and temporal differences in hydrology, temperature and water chemistry among the sampling campaigns, T-RFLP electropherograms from all samples were similar, indicating that the same bacterioplankton phylotypes dominated in the various habitats of the Delta throughout the year. However, principal component analysis (PCA) and partial least-squares regression (PLS) of T-RFLP profiles revealed consistent grouping of samples on a seasonal, but not a spatial, basis. ??-Proteobacteria related to Ralstonia, Actinobacteria related to Microthrix, and ??-Proteobacteria identical to the environmental Clone LD12 had the highest relative abundance in summer/fall T-RFLP profiles and were associated with low river flow, high pH, and a number of optical and chemical characteristics of dissolved organic carbon (DOC) indicative of an increased proportion of phytoplankton-produced organic material as opposed to allochthonous, terrestrially derived organic material. On the other hand, Geobacter-related ??-Proteobacteria showed a relative increase in abundance in T-RFLP analysis during winter/spring, and probably were washed out from watershed soils or sediment. Various phylotypes associated with the same phylogenetic division, based on tentative identification of T-RFLP fragments, exhibited diverse seasonal patterns, suggesting that ecological

Delta isobars in neutron stars

Directory of Open Access Journals (Sweden)

Pagliara Giuseppe

2015-01-01

Full Text Available The appearance of delta isobars in beta-stable matter is regulated by the behavior of the symmetry energy at densities larger than saturation density. We show that by taking into account recent constraints on the density derivative of the symmetry energy and the theoretical and experimental results on the excitations of delta isobars in nuclei, delta isobars are necessary ingredients for the equations of state used for studying neutron stars. We analyze the effect of the appearance of deltas on the structure of neutron stars: as in the case of hyperons, matter containing delta is too soft for allowing the existence of 2M⊙ neutron stars. Quark stars on the other hand, could reach very massive configurations and they could form from a process of conversion of hadronic stars in which an initial seed of strangeness appears through hyperons.

Design of a Narrow Bandwidth Bandpass Filter Using Compact Spiral Resonator with Chirality

Directory of Open Access Journals (Sweden)

Weiping Li

2016-01-01

Full Text Available In this article, a compact narrow-bandpass filter with high selectivity and improved rejection level is presented. For miniaturization, a pair of double negative (DNG cells consisting of quasi-planar chiral resonators are cascaded and electrically loaded to a microstrip transmission line; short ended stubs are introduced to expand upper rejection band. The structure is analyzed using equivalent circuit models and simulated based on EM simulation software. For validation, the proposed filter is fabricated and measured. The measured results are in good agreement with the simulated ones. By comparing to other filters in the references, it is shown that the proposed filter has the advantage of skirt selectivity and compact size, so it can be integrated more conveniently in modern wireless communication systems and microwave planar circuits.

X-ray diffraction study of delta-stabilized plutonium alloys under pressure

Energy Technology Data Exchange (ETDEWEB)

Faure, Ph, E-mail: philippe.faure@cea.f [CEA, Valduc, F-21120 Is-sur-Tille (France); Genestier, C. [CEA, Valduc, F-21120 Is-sur-Tille (France)

2010-02-15

Previous extensive studies of the delta -> alpha'-phase transformation induced by temperature and/or by pressure in delta-stabilized plutonium alloys indicate strong dependence on parameters such as solute type, solute distribution, chemical impurities, kinetics, thermodynamic path.... The present paper reports results obtained on two Pu-2.3at.%Ga binary alloys differing by solute homogenization treatment and studied under pressure by in situ by X-ray diffraction in diamond anvil cells. The gamma'-phase appears as an intermediate phase during the delta -> alpha'-phase transformation. In cored samples, unexpanded alpha'-phase is formed at the beginning of the transformation, from domains with low solute content, and expanded alpha'-phase subsequently forms (from domains with higher solute content) as the transformation progresses with the pressure increase.

Compact Microstrip Triple-Mode Bandpass Filters Using Dual-Stub-Loaded Spiral Resonators

Directory of Open Access Journals (Sweden)

K. D. Xu

2017-04-01

Full Text Available Two new microstrip triple-mode resonators loaded with T-shaped open stubs using axially and centrally symmetric spiral structures, respectively, are presented. Spiraled for circuit size reduction, these two half-wavelength resonators can both generate three resonant modes over a wide frequency band by loading two T-stubs with different lengths. Due to the structural symmetry, they can be analyzed by odd- and even-mode method. To validate the design concept, two compact bandpass filters (BPFs using these two novel resonators with center frequencies of 1.76 GHz and 2.44 GHz for the GSM1800 and WLAN/Zigbee applications, respectively, have been designed, fabricated and tested. The center frequencies and bandwidths can be tunable through the analysis of resonant frequency responses, fractional bandwidths and external quality factor versus the resonator parameters. The final measured results have achieved good consistence with the simulations of these two BPFs.

Improved γ-linolenic acid production in Mucor circinelloides by homologous overexpressing of delta-12 and delta-6 desaturases.

Science.gov (United States)

Zhang, Yao; Luan, Xiao; Zhang, Huaiyuan; Garre, Victoriano; Song, Yuanda; Ratledge, Colin

2017-06-21

γ-Linolenic acid (GLA) is important because of its nutritional value and medicinal applications. Although the biosynthetic pathways of some plant and microbial GLA have been deciphered, current understanding of the correlation between desaturases and GLA synthesis in oleaginous fungi is incomplete. In previous work, we found that a large amount of oleic acid (OA) had not been converted to linoleic acid (LA) or GLA in Mucor circinelloides CBS 277.49, which may be due to inadequate activities of the delta-12 or delta-6 desaturases, and thus leading to the accumulation of OA and LA. Thus, it is necessary to explore the main contributing factor during the process of GLA biosynthesis in M. circinelloides. To enhance GLA production in M. circinelloides, homologous overexpression of delta-12 and two delta-6 desaturases (named delta-6-1 and delta-6-2, respectively) were analyzed. When delta-6 desaturase were overexpressed in M. circinelloides, up to 43% GLA was produced in the total fatty acids, and the yield of GLA reached 180 mg/l, which were, respectively, 38 and 33% higher than the control strain. These findings revealed that delta-6 desaturase (especially for delta-6-1 desaturase) plays an important role in GLA synthesis by M. circinelloides. The strain overexpressing delta-6-1 desaturase may have potential application in microbial GLA production.

Delta check for blood groups: A step ahead in blood safety

Directory of Open Access Journals (Sweden)

Raj Nath Makroo

2017-01-01

Conclusion: Delta checks proved to be an effective tool for detecting blood group errors and prevention of accidental mismatched blood transfusions. Preanalytical errors in patient identification or sample labeling were the most frequent.

Modelling and validation of a simple and compact wide upper stop band ultra-wideband bandpass filter

Directory of Open Access Journals (Sweden)

Somdotta Roy Choudhury

2014-09-01

Full Text Available A compact ultra-wideband (UWB bandpass filter (BPF is proposed based on end coupled microstrip transmission line, defected ground structure and defected microstrip structure. The experimental filter shows a fractional bandwidth of 110% at a centre frequency, with two observable transmission zeros (attenuation poles at 2.1 and 11.7 GHz. Measured results exhibit an UWB passband from 3.02 to 10.6 GHz with mid-band insertion loss of 1.8 dB and group delay variation <0.45 ns. The BPF achieves a wide stopband with < −18 dB attenuation up to 20 GHz.

Entropy and optimality in river deltas

Science.gov (United States)

Tejedor, Alejandro; Longjas, Anthony; Edmonds, Douglas A.; Zaliapin, Ilya; Georgiou, Tryphon T.; Rinaldo, Andrea; Foufoula-Georgiou, Efi

2017-10-01

The form and function of river deltas is intricately linked to the evolving structure of their channel networks, which controls how effectively deltas are nourished with sediments and nutrients. Understanding the coevolution of deltaic channels and their flux organization is crucial for guiding maintenance strategies of these highly stressed systems from a range of anthropogenic activities. To date, however, a unified theory explaining how deltas self-organize to distribute water and sediment up to the shoreline remains elusive. Here, we provide evidence for an optimality principle underlying the self-organized partition of fluxes in delta channel networks. By introducing a suitable nonlocal entropy rate (nER) and by analyzing field and simulated deltas, we suggest that delta networks achieve configurations that maximize the diversity of water and sediment flux delivery to the shoreline. We thus suggest that prograding deltas attain dynamically accessible optima of flux distributions on their channel network topologies, thus effectively decoupling evolutionary time scales of geomorphology and hydrology. When interpreted in terms of delta resilience, high nER configurations reflect an increased ability to withstand perturbations. However, the distributive mechanism responsible for both diversifying flux delivery to the shoreline and dampening possible perturbations might lead to catastrophic events when those perturbations exceed certain intensity thresholds.

On the calibration of continuous, high-precision delta18O and delta2H measurements using an off-axis integrated cavity output spectrometer.

Science.gov (United States)

Wang, Lixin; Caylor, Kelly K; Dragoni, Danilo

2009-02-01

The (18)O and (2)H of water vapor serve as powerful tracers of hydrological processes. The typical method for determining water vapor delta(18)O and delta(2)H involves cryogenic trapping and isotope ratio mass spectrometry. Even with recent technical advances, these methods cannot resolve vapor composition at high temporal resolutions. In recent years, a few groups have developed continuous laser absorption spectroscopy (LAS) approaches for measuring delta(18)O and delta(2)H which achieve accuracy levels similar to those of lab-based mass spectrometry methods. Unfortunately, most LAS systems need cryogenic cooling and constant calibration to a reference gas, and have substantial power requirements, making them unsuitable for long-term field deployment at remote field sites. A new method called Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) has been developed which requires extremely low-energy consumption and neither reference gas nor cryogenic cooling. In this report, we develop a relatively simple pumping system coupled to a dew point generator to calibrate an ICOS-based instrument (Los Gatos Research Water Vapor Isotope Analyzer (WVIA) DLT-100) under various pressures using liquid water with known isotopic signatures. Results show that the WVIA can be successfully calibrated using this customized system for different pressure settings, which ensure that this instrument can be combined with other gas-sampling systems. The precisions of this instrument and the associated calibration method can reach approximately 0.08 per thousand for delta(18)O and approximately 0.4 per thousand for delta(2)H. Compared with conventional mass spectrometry and other LAS-based methods, the OA-ICOS technique provides a promising alternative tool for continuous water vapor isotopic measurements in field deployments. Copyright 2009 John Wiley & Sons, Ltd.

The evolution of a subaqueous delta in the Anthropocene: A stratigraphic investigation of the Brazos River delta, TX USA

Science.gov (United States)

Carlin, Joseph A.; Dellapenna, Timothy M.

2015-12-01

Globally, deltas are increasingly threatened by anthropogenic activities. As a result, deltas now evolve through the combined effects of natural and human-induced processes occurring throughout the fluvial-deltaic system. The Brazos River delta, located along the Texas coast in the northwestern Gulf of Mexico, and its watershed have been impacted by direct and indirect human activities since the late 19th century. This provides an opportunity to investigate how such alterations have shaped the evolution of a delta in the Anthropocene, a time when humans are drivers of geological change. Historic alteration to the delta and watershed include extensive agricultural activity, jetty construction at the mouth in the late 1890s, mouth diversion ~10 km to the southwest in 1929, and reservoir construction throughout the early and mid 20th Century. Three subaerial deltaic geometries provided the framework to connect subaerial deltaic responses, to the anthropogenic alterations, to the resulting stratigraphic characteristics observed in the subaqueous delta. This study utilized high-resolution geophysical data (swath bathymetry, side scan sonar, CHIRP subbottom profiling) on the subaqueous delta to investigate the subaqueous delta stratigraphy and infer the processes that shaped the deltaic record over time. The results showed distinct areas across the subaqueous delta that were dominated by erosion and deposition. Erosional areas corresponded to earlier growth phase depocenters being exposed at the surface, while the depositional areas corresponded to areas with the most recent growth phase depocenter overlying the earlier depocenters. These results highlight that the subaqueous depocenter has migrated westward over time, consistent with the observed changes to the subaerial delta. Additionally, the data showed that evidence for these past growth phases and depocenters may be preserved within the subaqueous delta, even after subaerial portions of the delta returned to pre

High-Bandwidth, High-Efficiency Envelope Tracking Power Supply for 40W RF Power Amplifier Using Paralleled Bandpass Current Sources

DEFF Research Database (Denmark)

Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

2005-01-01

This paper presents a high-performance power conversion scheme for power supply applications that require very high output voltage slew rates (dV/dt). The concept is to parallel 2 switching bandpass current sources, each optimized for its passband frequency space and the expected load current....... The principle is demonstrated with a power supply, designed for supplying a 40 W linear RF power amplifier for efficient amplification of a 16-QAM modulated data stream...

Fully integrated low-loss band-pass filters for wireless applications

International Nuclear Information System (INIS)

Rais-Zadeh, M; Kapoor, A; Lavasani, H M; Ayazi, F

2009-01-01

Fully integrated low insertion loss micromachined band-pass filters are designed and fabricated on the silicon substrate (ρ = 10–20 Ω cm, ε r = 11.9) for UHF applications. Filters are made of silver, which has the highest conductivity of all metals, to minimize the ohmic loss. A detailed analysis for realizing low insertion loss and high out-of-band rejection filters using elliptic magnitude characteristics is presented, and a comprehensive model to take into account inductive parasitics of the interconnects is developed. Temperature characteristics of the filters are measured and show stable performance. The presented filters are different from the previously reported lumped element filters in that all filters are fully integrated on silicon substrate and occupy a remarkably smaller die area. Two filters are fabricated using the silver micromachining technique with center frequencies at 1.05 and 1.35 GHz. The filters have a constant 3 dB bandwidth of 300 MHz (28.6% and 22.2%) and an insertion loss of 1.4–1.7 dB. The low insertion loss and CMOS compatibility make the presented filters suitable candidates for radio frequency integrated circuits

Authenticity assessment of gamma- and delta-decalactone from prunus fruits by gas chromatography combustion/pyrolysis isotope ratio mass spectrometry (GC-C/P-IRMS).

Science.gov (United States)

Tamura, Hirotoshi; Appel, Markus; Richling, Elke; Schreier, Peter

2005-06-29

Authenticity assessment of gamma-decalactone (1) and delta-decalactone (2) from peach (Prunus persica var. persica), apricot (Prunus armeniaca), and nectarine (Prunus persica var. nectarina) was performed using gas chromatography-isotope ratio mass spectrometry (GC-IRMS) in the combustion (C) and pyrolysis (P) mode. In addition, commercially available synthetic (nature-identical) 1 and 2 as well as biotechnologically produced samples (declared to be "natural") were characterized by their delta(2)H(V)(-)(SMOW) and delta(13)C(V)(-)(PDB) values. For the Prunus fruits under study, rather narrow ranges of delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) data of 1, varying from - 34.6 per thousand to - 38.4 per thousand and -160 per thousand to -206 per thousand, respectively, were obtained. Synthetic references of 1 showed delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) data ranging from -27.4 per thousand to -28.3 per thousand and -151 per thousand to -184 per thousand, respectively. Samples of 1 declared to be "natural" exhibited ranges from -28.1 per thousand to -29.2 per thousand and -192 per thousand to -286 per thousand for delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW), respectively. For 2 from peach, apricot, and nectarine, delta(13)C(V)(-)(PDB) values ranging from -34.0 per thousand to -37.9 per thousand were determined; the delta(2)H(V)(-)(SMOW) values ranged from -171 per thousand to -228 per thousand. The delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) data for synthetic 2 were -28.2 per thousand and -171 per thousand, respectively, that is, similar to those of 2 from "natural" origin, ranging from -27.7 per thousand to -30.1 per thousand and -185 per thousand to -230 per thousand for delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW), respectively. GC-C/P-IRMS allowed clear-cut analytical differentiation of the synthetic and "ex-plant" origin of 1 and 2, whereas narrow ranges of delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) data were found for samples of

Landscape scale controls on the vascular plant component of dissolved organic carbon across a freshwater delta

Science.gov (United States)

Eckard, Robert S.; Hernes, Peter J.; Bergamaschi, Brian A.; Stepanauskas, Ramunas; Kendall, Carol

2007-01-01

Lignin phenol concentrations and compositions were determined on dissolved organic carbon (DOC) extracts (XAD resins) within the Sacramento-San Joaquin River Delta (the Delta), the tidal freshwater portion of the San Francisco Bay Estuary, located in central California, USA. Fourteen stations were sampled, including the following habitats and land-use types: wetland, riverine, channelized waterway, open water, and island drains. Stations were sampled approximately seasonally from December, 1999 through May, 2001. DOC concentrations ranged from 1.3 mg L-1 within the Sacramento River to 39.9 mg L-1 at the outfall from an island drain (median 3.0 mg L-1), while lignin concentrations ranged from 3.0 μL-1 within the Sacramento River to 111 μL-1 at the outfall from an island drain (median 11.6 μL-1). Both DOC and lignin concentrations varied significantly among habitat/land-use types and among sampling stations. Carbon-normalized lignin yields ranged from 0.07 mg (100 mg OC)-1 at an island drain to 0.84 mg (100 mg OC)-1 for a wetland (median 0.36 mg (100 mg OC)-1), and also varied significantly among habitat/land-use types. A simple mass balance model indicated that the Delta acted as a source of lignin during late autumn through spring (10-83% increase) and a sink for lignin during summer and autumn (13-39% decrease). Endmember mixing models using S:V and C:V signatures of landscape scale features indicated strong temporal variation in sources of DOC export from the Delta, with riverine source signatures responsible for 50% of DOC in summer and winter, wetland signatures responsible for 40% of DOC in summer, winter, and late autumn, and island drains responsible for 40% of exported DOC in late autumn. A significant negative correlation was observed between carbon-normalized lignin yields and DOC bioavailability in two of the 14 sampling stations. This study is, to our knowledge, the first to describe organic vascular plant DOC sources at the level of localized

Production and decay properties of the delta (970) meson

International Nuclear Information System (INIS)

Gay, J.B.; Chaloupka, V.; Gavillet, Ph.; Hemingway, R.J.; Marzano, F.; Montanet, L.; Blokzijl, R.; Jongejans, B.; Massaro, G.G.G.; Heinen, P.M.; Metzger, W.J.; Timmermans, J.J.M.

1976-01-01

Using an 80 events per microbarn sample of K - p interactions at 4.2 GeV/c the production and decay properties of the delta(970) have been investigated in the following reactions: K - p→Σ + (1385)etaπ - and K - p→Σ + (1385)K 0 K - . (Auth.)

deltaPlotR: An R Package for Di?erential Item Functioning Analysis with Ango? s Delta Plot

OpenAIRE

David Magis; Bruno Facon

2014-01-01

Angoff's delta plot is a straightforward and not computationally intensive method to identify differential item functioning (DIF) among dichotomously scored items. This approach was recently improved by proposing an optimal threshold selection and by considering several item purification processes. Moreover, to support practical DIF analyses with the delta plot and these improvements, the R package deltaPlotR was also developed. The purpose of this paper is twofold: to outline the delta plot ...

Efficient sampling algorithms for Monte Carlo based treatment planning

International Nuclear Information System (INIS)

DeMarco, J.J.; Solberg, T.D.; Chetty, I.; Smathers, J.B.

1998-01-01

Efficient sampling algorithms are necessary for producing a fast Monte Carlo based treatment planning code. This study evaluates several aspects of a photon-based tracking scheme and the effect of optimal sampling algorithms on the efficiency of the code. Four areas were tested: pseudo-random number generation, generalized sampling of a discrete distribution, sampling from the exponential distribution, and delta scattering as applied to photon transport through a heterogeneous simulation geometry. Generalized sampling of a discrete distribution using the cutpoint method can produce speedup gains of one order of magnitude versus conventional sequential sampling. Photon transport modifications based upon the delta scattering method were implemented and compared with a conventional boundary and collision checking algorithm. The delta scattering algorithm is faster by a factor of six versus the conventional algorithm for a boundary size of 5 mm within a heterogeneous geometry. A comparison of portable pseudo-random number algorithms and exponential sampling techniques is also discussed

Delta hedging strategies comparison

DEFF Research Database (Denmark)

De Giovanni, Domenico; Ortobelli, S.; Rachev, S.T.

2008-01-01

In this paper we implement dynamic delta hedging strategies based on several option pricing models. We analyze different subordinated option pricing models and we examine delta hedging costs using ex-post daily prices of S&P 500. Furthermore, we compare the performance of each subordinated model...

Episodic nature of the delta 4-ene and delta 5-ene steroidogenic pathways and their relationship to the adreno-gonadal axis in stallions.

Science.gov (United States)

Ganjam, V K

1979-01-01

Changes in the daily secretory patterns of testosterone and other 17 beta-hydroxyandrogen, total oestrogens and total corticoids were investigated in 7 stallions. Pulsatile fluctuations in plasma hormone levels were found in the serial blood samples collected hourly for 24 h in all animals. The plasma profiles indicated that corticoids, oestrogens and androgens were secreted episodically at all times in stallions. A significant correlation was observed between the precursor and products of delta 4-ene and delta 5-ene pathways and in inverse correlation (r = -0.68; P less than 0.01) was observed between total androgens and total corticoids. The significance of these episodic fluctuations of the major steroid hormones are discussed.

The Enabling Delta Life Initiative - Global Programme of Action on Deltas - Programme description

NARCIS (Netherlands)

Driel, van W.F.; Skyllerstedt, S.; Wosten, J.H.M.

2014-01-01

Being ‘hotspots’ of human activity with generally high population densities, deltas are vulnerable to changes induced by a range of driving forces, both natural and anthropogenic. In addition to already existing challenges, uncertainty of the possible impacts of climate change, low lying deltas

Barbados Oxygen Isotope Data (delta 18O) for the Late Pleistocene

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Coral-based delta18O time-series derived from measurements made on submerged or drowned coral reef sequence. The core samples used have been described elsewhere (cf....

Effect of ageing on optical and thermal properties of YBa{sub 2}Cu{sub 3}O{sub 7}-{delta}

Energy Technology Data Exchange (ETDEWEB)

Nikolic, P.M.; Vujatovic, S.S.; Savic, S.M.; Ristic, M.M. [Institute of Technical Sciences of SASA, Belgrade (Czechoslovakia); Paraskevopoulos, K.M.; Zorbas, K.T. [Aristotle Univ., Thessaloniki (Greece). Solid State Section; Nikolic, M.V.; Aleksic, O.S. [Belgrade Univ. (Czechoslovakia). Center for Multidisciplinary Studies

2007-07-15

Photoacoustic phase and amplitude spectra of YBa{sub 2}Cu{sub 3}O{sub 7}-{delta} samples synthesised 18 years ago were measured and numerically analysed. The value of thermal diffusivity obtained on the aged samples was lower than the values obtained for fresh samples. Far infrared spectra of YBa{sub 2}Cu{sub 3}O{sub 7}-{delta} samples synthesised 18 years ago were recorded and analysed enabling determination of reflectivity peak phonon frequencies present at room temperature. X-ray diffraction analysis and far infrared reflectivity measurements enabled determination of a slight change of the oxygen content with time. The YBa{sub 2}Cu{sub 3}O{sub 7}-{delta} samples synthesised 18 years ago still remained superconducting, which was confirmed by resistivity measurements of the samples between 50 K and room temperature where the critical temperature was reduced from 93 to 73 K. Atomic force microscopy, scanning electron microscopy and energy dispersive X-ray microanalytical measurements were also performed confirming the composition of the sample. (orig.)

Photonic bandpass filter characteristics of multimode SOI waveguides integrated with submicron gratings.

Science.gov (United States)

Sah, Parimal; Das, Bijoy Krishna

2018-03-20

It has been shown that a fundamental mode adiabatically launched into a multimode SOI waveguide with submicron grating offers well-defined flat-top bandpass filter characteristics in transmission. The transmitted spectral bandwidth is controlled by adjusting both waveguide and grating design parameters. The bandwidth is further narrowed down by cascading two gratings with detuned parameters. A semi-analytical model is used to analyze the filter characteristics (1500  nm≤λ≤1650  nm) of the device operating in transverse-electric polarization. The proposed devices were fabricated with an optimized set of design parameters in a SOI substrate with a device layer thickness of 250 nm. The pass bandwidth of waveguide devices integrated with single-stage gratings are measured to be ∼24  nm, whereas the device with two cascaded gratings with slightly detuned periods (ΔΛ=2  nm) exhibits a pass bandwidth down to ∼10  nm.

Doomed to drown? Sediment dynamics in the human-controlled floodplains of the active Bengal Delta

Directory of Open Access Journals (Sweden)

Kimberly G. Rogers

2017-11-01

Full Text Available The Ganges-Brahmaputra-Meghna (Bengal Delta in Bangladesh has been described as a delta in peril of catastrophic coastal flooding because sediment deposition on delta plain surfaces is insufficient to offset rates of subsidence and sea level rise. Widespread armoring of the delta by coastal embankments meant to protect crops from flooding has limited natural floodplain deposition, and in the tidally dominated delta, dikes lead to rapid compaction and lowered land surface levels. This renders the deltaic floodplains susceptible to flooding by sea level rise and storm surges capable of breaching poorly maintained embankments. However, natural physical processes are spatially variable across the delta front and therefore the impact of dikes on sediment dispersal and morphology should reflect these variations. We present the first ever reported sedimentation rates from the densely populated and human-controlled floodplains of the central lower Bengal Delta. We combine direct sedimentation measurements and short-lived radionuclides to show that transport processes and lateral sedimentation are highly variable across the delta. Overall aggradation rates average 2.3 ± 9 cm y–1, which is more than double the estimated average rate of local sea level rise; 83% of sampled sites contained sediment tagged with detectable 7 Be, indicating flood-pulse sourced sediments are widely delivered to the delta plain, including embanked areas. A numerical model is then used to demonstrate lateral accretion patterns arising from 50 years of sedimentation delivered through smaller order channels. Dominant modes of transport are reflected in the sediment routing and aggradation across the lower delta plain, though embankments are major controls on sediment dynamics throughout the delta. This challenges the assumption that the Bengal Delta is doomed to drown; rather it signifies that effective preparation for climate change requires consideration of how infrastructure

QCD in the {delta}-regime

Energy Technology Data Exchange (ETDEWEB)

Bietenholz, W. [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Ciencias Nucleares; Cundy, N. [Seoul National Univ. (Korea, Republic of). Lattice Gauge Theory Research Center; Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Horsley, R.; Zanotti, J.M. [Edinburgh Univ. (United Kingdom). School of Physics; Nakamura, Y. [Tsukuba Univ., Ibaraki (Japan). Center for Computational Sciences; Pleiter, D. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Div.; Schierholz, G. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2011-03-15

The {delta}-regime of QCD is characterised by light quarks in a small spatial box, but a large extent in (Euclidean) time. In this setting a specific variant of chiral perturbation theory - the {delta}-expansion - applies, based on a quantum mechanical treatment of the quasi onedimensional system. In particular, for vanishing quark masses one obtains a residual pion mass M{sup R}{sub {pi}}, which has been computed to the third order in the {delta}-expansion. A comparison with numerical measurements of this residual mass allows for a new determination of some Low Energy Constants, which appear in the chiral Lagrangian. We first review the attempts to simulate 2-flavour QCD directly in the {delta}-regime. This is very tedious, but results compatible with the predictions for M{sup R}{sub {pi}} have been obtained. Then we show that an extrapolation of pion masses measured in a larger volume towards the {delta}-regime leads to good agreement with the theoretical predictions. From those results, we also extract a value for the (controversial) sub-leading Low Energy Constant anti l{sub 3}. (orig.)

Tidal controls on river delta morphology

Science.gov (United States)

Hoitink, A. J. F.; Wang, Z. B.; Vermeulen, B.; Huismans, Y.; Kästner, K.

2017-09-01

River delta degradation has been caused by extraction of natural resources, sediment retention by reservoirs, and sea-level rise. Despite global concerns about these issues, human activity in the world’s largest deltas intensifies. Harbour development, construction of flood defences, sand mining and land reclamation emerge as key contemporary factors that exert an impact on delta morphology. Tides interacting with river discharge can play a crucial role in the morphodynamic development of deltas under pressure. Emerging insights into tidal controls on river delta morphology suggest that--despite the active morphodynamics in tidal channels and mouth bar regions--tidal motion acts to stabilize delta morphology at the landscape scale under the condition that sediment import during low flows largely balances sediment export during high flows. Distributary channels subject to tides show lower migration rates and are less easily flooded by the river because of opposing non-linear interactions between river discharge and the tide. These interactions lead to flow changes within channels, and a more uniform distribution of discharge across channels. Sediment depletion and rigorous human interventions in deltas, including storm surge defence works, disrupt the dynamic morphological equilibrium and can lead to erosion and severe scour at the channel bed, even decades after an intervention.

Delta Semantics Defined By Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt; Kyng, Morten; Madsen, Ole Lehrmann

and the possibility of using predicates to specify state changes. In this paper a formal semantics for Delta is defined and analysed using Petri nets. Petri nets was chosen because the ideas behind Petri nets and Delta concide on several points. A number of proposals for changes in Delta, which resulted from...

Notes on basis band-pass circuits; Notes sur les circuits de base passe-bande

Energy Technology Data Exchange (ETDEWEB)

Ailloud, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1959-07-01

Resistor load amplifier stages, basic band-pass RC networks, conventional single-tuned circuits, have the same transfer function. Common properties and differences because diverse magnitude of parameters with proposed problems are exposed. Next the case of several cascaded stages (or networks) is examined when there is no reaction ones to another. (author) [French] Les etages amplificateurs a resistances, les circuits passe-bande RC elementaires, le circuit resonnant classique possedent la meme fonction de transfert. On fait ressortir les proprietes communes et les differences de comportement dues aux ordres de grandeur qu'il est possible de donner aux parametres en fonction des problemes a resoudre. On examine ensuite le cas de plusieurs etages (ou de plusieurs circuits) en cascade lorsqu'ils ne reagissent pas les uns sur les autres. (auteur)

Optimality and self-organization in river deltas

Science.gov (United States)

Tejedor, A.; Longjas, A.; Edmonds, D. A.; Zaliapin, I. V.; Georgiou, T. T.; Rinaldo, A.; Foufoula-Georgiou, E.

2017-12-01

Deltas are nourished by channel networks, whose connectivity constrains, if not drives, the evolution, functionality and resilience of these systems. Understanding the coevolution of deltaic channels and their flux organization is crucial for guiding maintenance strategies of these highly stressed systems from a range of anthropogenic activities. However, in contrast to tributary channel networks, to date, no theory has been proposed to explain how deltas self-organize to distribute water and sediment to the delta top and the shoreline. Here, we hypothesize the existence of an optimality principle underlying the self-organized partition of fluxes in delta channel networks. Specifically, we hypothesize that deltas distribute water and sediment fluxes on a given delta topology such as to maximize the diversity of flux delivery to the shoreline. By introducing the concept of nonlocal Entropy Rate (nER) and analyzing ten field deltas in diverse environments, we present evidence that supports our hypothesis, suggesting that delta networks achieve dynamically accessible maxima of their nER. Furthermore, by analyzing six simulated deltas using the Delf3D model and following their topologic and flux re-organization before and after major avulsions, we further study the evolution of nER and confirm our hypothesis. We discuss how optimal flux distributions in terms of nER, when interpreted in terms of resilience, are configurations that reflect an increased ability to withstand perturbations.

Houtman Abrolhos Isotope (delta 18O, delta 13C) Data for 1795 to 1994

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — DESCRIPTION: VARIABLES AND UNITS: Column #1: core depth in mm Column #2: delta C-13 vs V-PDB Column #3: delta O-18 vs V-PDB Column #4: assigned date in years A.D....

Delta infection evidenced by radioimmunoanalysis in selected collectives

Energy Technology Data Exchange (ETDEWEB)

Kselikova, M; Horejsi, J; Urbankova, J

1987-01-01

The presence of the Delta agent within the population was tested by means of the Delta-antibody radioimmunoassay using competitive kits of the firms ABBOTT (ABBOTT-ANTI-DELTA) and SORIN (AB-DELTAK). The Delta-antibody was found in 3.2% HBV patients, 5% HBsAg carriers, and in 20.8% of specific anti-Hbs-immunoglobulin. In hemophiliacs and blood donors no Delta-antibody was seen.

Delta infection evidenced by radioimmunoanalysis in selected collectives

International Nuclear Information System (INIS)

Kselikova, M.; Horejsi, J.; Urbankova, J.

1987-01-01

The presence of the Delta agent within the population was tested by means of the Delta-antibody radioimmunoassay using competitive kits of the firms ABBOTT (ABBOTT-ANTI-DELTA) and SORIN (AB-DELTAK). The Delta-antibody was found in 3.2% HBV patients, 5% HBsAg carriers, and in 20.8% of specific anti-Hbs-immunoglobulin. In hemophiliacs and blood donors no Delta-antibody was seen. (author)

Frequency of CCR5delta32 in Brazilian populations

Directory of Open Access Journals (Sweden)

A.E. Vargas

2006-03-01

Full Text Available A sample of 103 randomly chosen healthy individuals from Alegrete, RS, Brazil, was tested for the CCR5delta32 allele, which is known to influence susceptibility to HIV-1 infection. The CCR5delta32 allele was identified by PCR amplification using specific primers flanking the region of deletion, followed by electrophoresis on a 3% agarose gel. The data obtained were compared to those reported for other populations and interpreted in terms of Brazilian history. The individuals studied came from a highly admixed population. Most of them were identified as white (N = 59, while blacks and browns (mulattoes were N = 13 and N = 31, respectively. The observed frequencies, considering the white, black and brown samples (6.8, 3.8, and 6.4%, respectively, suggest an important European parental contribution, even in populations identified as black and brown. However, in Brazil as a whole, this allele shows gradients indicating a relatively good correlation with the classification based on skin color and other physical traits, used here to define major Brazilian population groups.

A planar and tunable bandpass filter on a ferrite substrate with integrated windings

KAUST Repository

Arabi, Eyad A.

2015-05-01

Tunable Filters that are based on ferrite materials are often biased by external magnets or coils which are large and bulky. In this work a completely planar, CPW-based bandpass filter is presented with integrated windings. Due to these windings the size of the filter is only 26mm × 34mm × 0.38mm which is orders of magnitude smaller than the traditional designs with external windings. The filter is realized by electroplating of Copper over seed layers of Titanium and Gold over a YIG substrate. The fabricated filter achieves a tunability of 3.4% without any external magnets or coils. A good insertion loss of 2.3 dBs and rejection greater than 50 dBs have been obtained. To the best of the authors knowledge, this design is the first ferrite-based design that is completely planar and self-biased.

Dermal absorption of the insecticide lindane (1 delta, 2 delta, 3 beta, 4 delta, 5 delta, 6 beta-hexachlorocyclohexane) in rats and rhesus monkeys: Effect of anatomical site

International Nuclear Information System (INIS)

Moody, R.P.; Ritter, L.

1989-01-01

Dermal absorption of the insecticide lindane (1 delta, 2 delta, 3 beta, 4 delta, 5 delta, 6 beta-hexachlorocyclohexane) was determined in rats and rhesus monkeys. Lindane is in widespread use as a 1% cream or lotion scabicide formulation and as a 1% miticide shampoo for body lice control in humans. Results obtained following our in vivo dermal absorption procedure demonstrated that 18 +/- 4.1%, 34 +/- 5.2%, and 54 +/- 26.3% of the applied dose was absorbed following topical applications at a rate of 1.5 micrograms/cm2 (6.2 micrograms/100 microliters of acetone) of the 14C-labeled pesticide to 4.2-cm2 regions of the forearm (n = 8), forehead (n = 7), and palm (n = 4) of rhesus monkeys, respectively. Dose sites were washed with soapy water 24 h posttreatment. Comparative studies in rats (n = 5) dosed middorsally demonstrated 31 +/- 9.5% absorption. Statistical analysis of the 14C excretion kinetics demonstrated slower clearance of lindane from rats than monkey forearm, forehead, or palm. Intramuscular (im) injections of 14C-lindane gave 52 +/- 7.1% recovery in monkey (n = 8) and 64 +/- 5.9% in rats (n = 5), suggesting body storage of this lipophilic chemical

Design of an S band narrow-band bandpass BAW filter

Science.gov (United States)

Gao, Yang; Zhao, Kun-li; Han, Chao

2017-11-01

An S band narrowband bandpass filter BAW with center frequency 2.460 GHz, bandwidth 41MHz, band insertion loss - 1.154 dB, the passband ripple 0.9 dB, the out of band rejection about -42.5dB@2.385 GHz; -45.5dB@2.506 GHz was designed for potential UAV measurement and control applications. According to the design specifications, the design is as follows: each FBAR's stack was designed in BAW filter by using Mason model. Each FBAR's shape was designed with the method of apodization electrode. The layout of BAW filter was designed. The acoustic-electromagnetic cosimulation model was built to validate the performance of the designed BAW filter. The presented design procedure is a common one, and there are two characteristics: 1) an A and EM co-simulation method is used for the final BAW filter performance validation in the design stage, thus ensures over-optimistic designs by the bare 1D Mason model are found and rejected in time; 2) An in-house developed auto-layout method is used to get compact BAW filter layout, which simplifies iterative error-and-try work here and output necessary in-plane geometry information to the A and EM cosimulation model.

Determination of the positions and residues of the. delta. /sup + +/ and. delta. /sup 0/ poles. [Phase shifts,coulomb corrections

Energy Technology Data Exchange (ETDEWEB)

Vasan, S S [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics

1976-04-19

The poles and the associated residues in the ..pi..N P/sub 33/ amplitude corresponding to the resonances ..delta../sup + +/ and ..delta../sup 0/ are determined by fitting the ..pi../sup +/p and ..pi../sup -/p hadronic phase shifts from the Carter 73 analysis. The ..delta../sup + +/ and ..delta../sup 0/ pole positions are determined also from the nuclear phase shifts, these being the phase shifts made up of the hadronic phase shifts plus the Coulomb corrections. The pole positions obtained from the two sets of phase shifts are different, the differences being larger in the case of the ..delta../sup + +/.

Isotopic composition of Danube water in the pre-delta section from the years 2009 - 2012

Directory of Open Access Journals (Sweden)

RANK Dieter

2013-12-01

Full Text Available The isotopic composition of river water in the Danube Basin is mainly governed by the isotopic composition of precipitation in the catchment area, evaporation effects play only a minor role. Short-term and long-term isotope signals from precipitation are thus transmitted through the whole catchment. The isotopic composition of Danube water in the Delta region so provides an integrated isotope signal for climatic/hydrological conditions and changes in the whole catchment. The aim of this investigation was to establish a representative isotope monitoring near the Danube Delta. The results showed that the Danube River is regarding isotope content fully mixed at the bifurcation of the Danube Delta arms. Therefore routine sampling at only one location in the pre-delta region should be sufficient to obtain a representative isotope record for the whole Danube Basin. The δ 18 O time series from November 2009 to May 2012 (sampling twice a month shows seasonal variations in the range of -9.8 ‰ ± 0.7 ‰ with a minimum in spring and a maximum in autumn. The tritium results exhibit the influence of short term contaminations due to human activities. The expected “environmental” tritium content of river water in Central Europe would be about 10 TU. During this investigation 3 H values up to 100 TU were observed in the pre-delta section. This indicates short terms releases of tritium from local sources such as nuclear power plants in the Danube river system.

The Concentration Dependence of the (Delta)s Term in the Gibbs Free Energy Function: Application to Reversible Reactions in Biochemistry

Science.gov (United States)

Gary, Ronald K.

2004-01-01

The concentration dependence of (delta)S term in the Gibbs free energy function is described in relation to its application to reversible reactions in biochemistry. An intuitive and non-mathematical argument for the concentration dependence of the (delta)S term in the Gibbs free energy equation is derived and the applicability of the equation to…

78 FR 21491 - DeltaPoint Capital IV, L.P., DeltaPoint Capital IV (New York), L.P.; Notice Seeking Exemption...

Science.gov (United States)

2013-04-10

... SMALL BUSINESS ADMINISTRATION [License No. 02/02-0662, 02/02-0661] DeltaPoint Capital IV, L.P., DeltaPoint Capital IV (New York), L.P.; Notice Seeking Exemption Under Section 312 of the Small Business Investment Act, Conflicts of Interest Notice is hereby given that DeltaPoint Capital IV, L.P. and DeltaPoint...

Mida pakub Delta? / Teele Kurm

Index Scriptorium Estoniae

Kurm, Teele

2011-01-01

Politsei- ja Piirivalveamet võtab kasutusele ühise Siseministeeriumi infotehnoloogia- ja arenduskeskuse ning Webmedia AS koostööna loodud dokumendihaldussüsteemi Delta. Kust sai Delta oma nime? Projekti "Dokumendihaldussüsteemi juurutamine Siseministeeriumi haldusalas" eesmärgid

Protracted outbreak of severe delta hepatitis: experience in an isolated Amerindian population of the Upper Orinoco basin.

Science.gov (United States)

Torres, J R; Mondolfi, A

1991-01-01

In an investigation of a 21-year-old epidemic of severe hepatitis, 80 serum samples were studied from two isolated Yanomami Amerindian populations of the Upper Orinoco basin in Venezuela. Of the assayed samples, 30.6% were positive for hepatitis B surface antigen (HBsAg), 53.7% were considered to reflect immunity to infection with hepatitis B virus (HBV), and only 16.2% were believed to reflect susceptibility to HBV infection; 82.5% of the samples tested positive for any marker of HBV infection. Thirty-one (39.7%) of 78 samples were also positive for antibody to delta antigen, including 91.6% of those positive for HBsAg and 20.9% of those immune to HBV. Our findings provide evidence of a high prevalence of HBV infection in this population. Furthermore, the high prevalence of antibody to delta antigen strongly suggests that coinfections with HBV or superinfections with hepatitis delta virus (HDV) in HBV carriers may be an important factor in the occurrence of an unusually high number of cases of fulminant hepatitis and of chronic liver disease. Serum samples obtained at the beginning of the outbreak 13 years earlier from 36 selected cases in the same population revealed a high rate of HBV infection (96.5%). All six HBsAg carriers from whom enough serum remained to be assayed were positive for antibody to delta antigen. Our findings indicate that the outbreak coincided with the introduction of HDV into a population with an already-high prevalence of HBV infection.

Investigation of the heavy metal pollution of Danube delta sediments by TTPIXE analysis

International Nuclear Information System (INIS)

David, I.; Ciortea, C.; Enescu, S.; Fluerasu, D.; Dumitriu, D. E.; Dinescu, L.; Stochioiu, A.

2001-01-01

The elemental composition of sediments collected from some Danube Delta lakes (Malita, Furtuna, Lund, Mester and Sinoe), which are located in active sedimentary zones, was investigated by using two complementary methods: thick target proton-induced X-ray emission (TTPIXE) and instrumental neutron activation analysis (INAA) or X-ray fluorescence (XRF). The goal was to obtain a complete survey of heavy metal pollution and reconstruct recent pollution history in these Danube Delta lakes. Vertical distribution was analyzed, except for the case of Sinoe Lake, from which samples were collected only at the surface. During PIXE measurements, the pellets of 12 mm diameter and ∼ 1.5 mm thickness were bombarded using 3 MeV proton beams delivered by the FN-Tandem accelerator of IFIN-HH. The X-ray spectra were measured with a Ge-HP detector of 180 eV/5.9 KeV energy resolution for some micro.C charge accumulation. Control samples of reference sediments (IAEA, SL-1 and SOIL-7) prepared in the same conditions were also measured. Corrections were made for proton stopping and X-ray self-attenuation in the thick samples. Thirty-eight samples from the first four lakes and 7 samples from Sinoe Lake were analyzed, and the concentrations of 27 elements in every sample were determined by TTPIXE method. The following elements: S, Ca, Ti, Mn, Ni, Ga, Pb, and Hg could not be determined by INAA in our conditions. A typical measured spectrum where the presence of various pollutant elements is shown. Five elements - As, Br, Cr, Sb and Zn - were identified as pollutants by INAA method, showing concentrations about 1.5-2 x larger at the sediments surface. The vertical distribution of the presumed pollutant elements generally reflected the pollution history of the Danube Delta, namely a steady increase in pollution till the end of the 1980s, which can be associated with intense industrialization of Central and Eastern European countries prior to 1990. We think the interplay with TTPIXE method

Collaborative Innovation Research on High-tech Industry in the Center Delta

Directory of Open Access Journals (Sweden)

Yan Jingdong

2017-01-01

Full Text Available As a strong point in the Middle Rises Strategy, the Center Delta is of great significance to high-tech industry development. While the collaborative innovation is an effective way to promote the coordinated development of regional economy. This article selected electronic and communication equipment manufacturing industry of 3 provinces in the Center Delta as samples, built evaluation index system of collaborative innovation of high-tech industry, and put the relevant data into the system coordination degree model, in order to get the synergy of industrial innovation system and innovation environment system of 3 provinces. The empirical results shown that the industrial innovation system and innovation environment system coordination degree of Hubei province was the highest, while Jiangxi province was the lowest. Based on the empirical result analysis of the above-mentioned systems, this article put forward suggestions to promote the development of the high-tech industry collaborative innovation in the Center Delta.

Changes in the areal extents of the Athabasca River, Birch River, and Cree Creek Deltas, 1950-2014, Peace-Athabasca Delta, Canada

Science.gov (United States)

Timoney, Kevin; Lee, Peter

2016-04-01

Deltas form where riverborne sediment accumulates at the interface of river mouths and their receiving water bodies. Their areal extent is determined by the net effect of processes that increase their extent, such as sediment accumulation, and processes that decrease their extent, such as erosion and subsidence. Through sequential mapping and construction of river discharge and sediment histories, this study examined changes in the subaerial extents of the Cree Creek and Athabasca River Deltas (both on the Athabasca River system) and the Birch River Delta in northern Canada over the period 1950-2014. The purpose of the study was to determine how, when, and why the deltas changed in areal extent. Temporal growth patterns were similar across the Athabasca and Birch River systems indicative of a climatic signal. Little or no areal growth occurred from 1950 to 1968; moderate growth occurred between 1968 and the early to mid-1980s; and rapid growth occurred between 1992 and 2012. Factors that affected delta progradation included dredging, sediment supply, isostatic drowning, delta front bathymetry, sediment capture efficiency, and storms. In relation to sediment delivered, areal growth rates were lowest in the Athabasca Delta, intermediate in the Birch Delta, and highest in the Cree Creek Delta. Annual sediment delivery is increasing in the Cree Creek Delta; there were no significant trends in annual sediment delivery in the Birch and Athabasca Deltas. There was a lag of up to several years between sediment delivery events and progradation. Periods of delta progradation were associated with low water levels of the receiving basins. Predicted climate-change driven declines in river discharge and lake levels may accelerate delta progradation in the region. In the changing ecosystems of northeastern Alberta, inadequate monitoring of vegetation, landforms, and sediment regimes hampers the elucidation of the nature, rate, and causality of ecosystem changes.

Insecticide residue monitoring in sediments water fish and mangroves at the Cimanuk Delta

International Nuclear Information System (INIS)

Sumatra, Made

1982-01-01

The water and sediments from the upper stream of Cimanuk river carry insecticide residues especially during the rainy season. The insecticides are deposited in the estuary of Cimanuk river and along the coast of Cimanuk delta. The insecticide residues found at the delta were diazinon thiodan DDE o p-DDT and p p-DDT. Those insecticides are found in most of the water sediments and mangrove leaves samples and some of fishes samples. The samples were taken from the river the estuary the sea, the tambaks, the coast line, and from paddy field. No insecticide residue is found in the water samples taken in the dry season but they are found in the sediment samples taken in both the dry and rainy season. Generally the diazinon residues are higher at the surface than at 0.5m depth in compact sediment but they are higher at 0.5m depth than at the surface of the mud from the coast line. Diazinon and thiodan are found only in three fish samples out of twenty samples analyzed but thiodan is found in almost all of the sediment and mangrove leaves samples. DDT is found in almost all of the samples analyzed. (author)

An analytical framework for strategic delta planning

NARCIS (Netherlands)

Seijger, C.; Douven, W.; Halsema, van G.; Hermans, L.; Evers, J.; Phi, H.L.; Khan, M.F.; Brunner, J.; Pols, L.; Ligtvoet, W.; Koole, S.; Slager, K.; Vermoolen, M.S.; Hasan, S.; Thi Minh Hoang, Vo

2017-01-01

Sectoral planning on water, agriculture and urban development has not been able to prevent increased flood risks and environmental degradation in many deltas. Governments conceive strategic delta planning as a promising planning approach and develop strategic delta plans. Such plans are linked to

Spatio-temporal distributions of delta¹⁸O, delta D and salinity in the Arabian Sea: Identifying processes and controls

Digital Repository Service at National Institute of Oceanography (India)

Deshpande, R.D; Muraleedharan, P.M.; Singh, R.L.; Kumar, B.; Rao, M.S.; Dave, M.; Sivakumar, K.U.; Gupta, S.K.

the geographic distributions of the delta^18O and S; (2) in spite of a large scatter, a statistically significant delta^18O–S relationship can be identified in much of the investigated part of the AS; (3) the delta^18O– delta...

Microstructural analysis of the {delta} to {alpha}' phase transformation in plutonium alloys using X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Platteau, C; Ravat, B; Texier, G; Oudot, B; Delaunay, F, E-mail: brice.ravat@cea.fr [CEA Valduc 21120 Is sur Tille (France)

2010-03-15

The partial martensitic {delta}{yields}{alpha}' transformation in plutonium alloys is sensitive to chemical composition, sample thermal history, as well as crystalline defects. The present work investigates the {delta}-Pu phase microstructure before and after the martensitic transformation {delta}{yields}{delta}+{alpha}'. More precisely, microstructural modifications of the host {delta}-phase, resulting from the stress induced by a cell volume difference of 19% between the {delta} and {alpha}'-phases, were analysed. Microstructural information about crystallite size and microstrain of a highly homogenized Pu-Ga alloy was extracted from x-ray diffraction patterns using a three dimension crystallite size and microstrain model. This is available in Rietveld refinement software and consists in anisotropic broadening analysis of diffraction peaks. Crystallite size doesn't significantly change with the phase transformation contrary to microstrain that is multiplied, on average, by five. Furthermore, internal normal and shear microstress are multiplied, respectively, by 2 and 13 when {alpha}'-phase appears. Last, dislocation densities, calculated from crystallite size and microstrain, are compared to TEM results available in the literature.

Adaptive Delta Management: cultural aspects of dealing with uncertainty

Science.gov (United States)

Timmermans, Jos; Haasnoot, Marjolijn; Hermans, Leon; Kwakkel, Jan

2016-04-01

Deltas are generally recognized as vulnerable to climate change and therefore a salient topic in adaptation science. Deltas are also highly dynamic systems viewed from physical (erosion, sedimentation, subsidence), social (demographic), economic (trade), infrastructures (transport, energy, metropolization) and cultural (multi-ethnic) perspectives. This multi-faceted dynamic character of delta areas warrants the emergence of a branch of applied adaptation science, Adaptive Delta Management, which explicitly focuses on climate adaptation of such highly dynamic and deeply uncertain systems. The application of Adaptive Delta Management in the Dutch Delta Program and its active international dissemination by Dutch professionals results in the rapid dissemination of Adaptive Delta Management to deltas worldwide. This global dissemination raises concerns among professionals in delta management on its applicability in deltas with cultural conditions and historical developments quite different from those found in the Netherlands and the United Kingdom where the practices now labelled as Adaptive Delta Management first emerged. This research develops an approach and gives a first analysis of the interaction between the characteristics of different approaches in Adaptive Delta Management and their alignment with the cultural conditions encountered in various delta's globally. In this analysis, first different management theories underlying approaches to Adaptive Delta Management as encountered in both scientific and professional publications are identified and characterized on three dimensions: The characteristics dimensions used are: orientation on today, orientation on the future, and decision making (Timmermans, 2015). The different underlying management theories encountered are policy analysis, strategic management, transition management, and adaptive management. These four management theories underlying different approaches in Adaptive Delta Management are connected to

NTS radiological assessment project: comparison of delta-surface interpolation with kriging for the Frenchman Lake region of area 5

International Nuclear Information System (INIS)

Foley, T.A. Jr.

1981-08-01

The primary objective of this report is to compare the results of delta surface interpolation with kriging on four large sets of radiological data sampled in the Frenchman Lake region at the Nevada Test Site. The results of kriging, described in Barnes, Giacomini, Reiman, and Elliott, are very similar to those using the delta surface interpolant. The other topic studied is in reducing the number of sample points and obtaining results similar to those using all of the data. The positive results here suggest that great savings of time and money can be made. Furthermore, the delta surface interpolant is viewed as a contour map and as a three dimensional surface. These graphical representations help in the analysis of the large sets of radiological data

Complex rearrangements within the human J delta-C delta/J alpha-C alpha locus and aberrant recombination between J alpha segments

NARCIS (Netherlands)

Baer, R.; Boehm, T.; Yssel, H.; Spits, H.; Rabbitts, T. H.

1988-01-01

We have examined DNA rearrangements within a 120 kb cloned region of the human T cell receptor J delta-C delta/J alpha-C alpha locus. Three types of pattern emerge from an analysis of T cell lines and clones. Firstly, cells with two rearrangements within J delta-C delta; secondly, cells with one

High-Q Tl2CaBa2Cu2O8 high-Tc superconducting quasi-optical millimeter-wave bandpass filters working at 77 K

International Nuclear Information System (INIS)

Zhang, D.; Fetterman, H.R.

1994-01-01

Tl 2 CaBa 2 Cu 2 O 8 high-temperature superconducting thin films with T c 's of over 100 K on LaAlO 3 substrates were used to fabricate quasi-optical millimeter-wave bandpass filters. Q-factors of over 400 were achieved, at liquid nitrogen temperatures from these filters at W-band frequencies (75--110 GHz)

Sediment and Vegetation Controls on Delta Channel Networks

Science.gov (United States)

Lauzon, R.; Murray, A. B.; Piliouras, A.; Kim, W.

2016-12-01

Numerous factors control the patterns of distributary channels formed on a delta, including water and sediment discharge, grain size, sea level rise rates, and vegetation type. In turn, these channel networks influence the shape and evolution of a delta, including what types of plant and animal life - such as humans - it can support. Previous fluvial modeling and flume experiments, outside of the delta context, have addressed how interactions between sediment and vegetation, through their influence on lateral transport of sediment, determine what type of channel networks develops. Similar interactions likely also shape delta flow patterns. Vegetation introduces cohesion, tending to reduce channel migration rates and strengthen existing channel banks, reinforcing existing channels and resulting in localized, relatively stable flow patterns. On the other hand, sediment transport processes can result in lateral migration and frequent switching of active channels, resulting in flow resembling that of a braided stream. While previous studies of deltas have indirectly explored the effects of vegetation through the introduction of cohesive sediment, we directly incorporate key effects of vegetation on flow and sediment transport into the delta-building model DeltaRCM to explore how these effects influence delta channel network formation. Model development is informed by laboratory flume experiments at UT Austin. Here we present initial results of experiments exploring the effects of sea level rise rate, sediment grain size, vegetation type, and vegetation growth rate on delta channel network morphology. These results support the hypothesis that the ability for lateral transport of sediment to occur plays a key role in determining the evolution of delta channel networks and delta morphology.

Particle analysis on concentrated particle suspensions by transmission fluctuation spectrometry with band-pass filters: part 2. Experimental results

International Nuclear Information System (INIS)

Xu, Yamin; Shen, Jianqi; Cai, Xiaoshu; Riebel, Ulrich

2010-01-01

Transmission fluctuation spectrometry (TFS), as a new method of online and real-time particle analysis developed in recent years, can measure the particle size distribution and particle concentration simultaneously. In the preceding paper, high concentration effects on the TFS using band-pass filters were investigated by numerical simulation, and empirical expressions to correct the effects were obtained. This paper presents a study on the TFS measurements in which the particle concentration varies in a very wide dynamic range. Finally, reasonable results on both the particle size distribution and particle concentration are obtained by introducing empirical corrections into the inversion algorithm

Perspectives on bay-delta science and policy

Science.gov (United States)

Healey, Michael; Dettinger, Michael; Norgaard, Richard

2016-01-01

The State of Bay–Delta Science 2008 highlighted seven emerging perspectives on science and management of the Delta. These perspectives had important effects on policy and legislation concerning management of the Delta ecosystem and water exports. From the collection of papers that make up the State of Bay–Delta Science 2016, we derive another seven perspectives that augment those published in 2008. The new perspectives address nutrient and contaminant concentrations in Delta waters, the failure of the Delta food web to support native species, the role of multiple stressors in driving species toward extinction, and the emerging importance of extreme events in driving change in the ecosystem and the water supply. The scientific advances that underpin these new perspectives were made possible by new measurement and analytic tools. We briefly discuss some of these, including miniaturized acoustic fish tags, sensors for monitoring of water quality, analytic techniques for disaggregating complex contaminant mixtures, remote sensing to assess levee vulnerability, and multidimensional hydrodynamic modeling. Despite these new tools and scientific insights, species conservation objectives for the Delta are not being met. We believe that this lack of progress stems in part from the fact that science and policy do not incorporate sufficiently long-term perspectives. Looking forward half a century was central to the Delta Visioning process, but science and policy have not embraced this conceptual breadth. We are also concerned that protection and enhancement of the unique cultural, recreational, natural resource, and agricultural values of the Delta as an evolving place, as required by the Delta Reform Act, has received no critical study and analysis. Adopting wider and longer science and policy perspectives immediately encourages recognition of the need for evaluation, analysis, and public discourse on novel conservation approaches. These longer and wider perspectives

Perspectives on Bay–Delta Science and Policy

Directory of Open Access Journals (Sweden)

Michael Healey

2016-12-01

Full Text Available doi: https://doi.org/10.15447/sfews.2016v14iss4art6The State of Bay–Delta Science 2008 highlighted seven emerging perspectives on science and management of the Delta. These perspectives had important effects on policy and legislation concerning management of the Delta ecosystem and water exports. From the collection of papers that make up the State of Bay–Delta Science 2016, we derive another seven perspectives that augment those published in 2008. The new perspectives address nutrient and contaminant concentrations in Delta waters, the failure of the Delta food web to support native species, the role of multiple stressors in driving species toward extinction, and the emerging importance of extreme events in driving change in the ecosystem and the water supply. The scientific advances that underpin these new perspectives were made possible by new measurement and analytic tools. We briefly discuss some of these, including miniaturized acoustic fish tags, sensors for monitoring of water quality, analytic techniques for disaggregating complex contaminant mixtures, remote sensing to assess levee vulnerability, and multidimensional hydrodynamic modeling. Despite these new tools and scientific insights, species conservation objectives for the Delta are not being met. We believe that this lack of progress stems in part from the fact that science and policy do not incorporate sufficiently long-term perspectives. Looking forward half a century was central to the Delta Visioning process, but science and policy have not embraced this conceptual breadth. We are also concerned that protection and enhancement of the unique cultural, recreational, natural resource, and agricultural values of the Delta as an evolving place, as required by the Delta Reform Act, has received no critical study and analysis. Adopting wider and longer science and policy perspectives immediately encourages recognition of the need for evaluation, analysis, and public discourse on

Sensitivity of postplanning target and OAR coverage estimates to dosimetric margin distribution sampling parameters.

Science.gov (United States)

Xu, Huijun; Gordon, J James; Siebers, Jeffrey V

2011-02-01

A dosimetric margin (DM) is the margin in a specified direction between a structure and a specified isodose surface, corresponding to a prescription or tolerance dose. The dosimetric margin distribution (DMD) is the distribution of DMs over all directions. Given a geometric uncertainty model, representing inter- or intrafraction setup uncertainties or internal organ motion, the DMD can be used to calculate coverage Q, which is the probability that a realized target or organ-at-risk (OAR) dose metric D, exceeds the corresponding prescription or tolerance dose. Postplanning coverage evaluation quantifies the percentage of uncertainties for which target and OAR structures meet their intended dose constraints. The goal of the present work is to evaluate coverage probabilities for 28 prostate treatment plans to determine DMD sampling parameters that ensure adequate accuracy for postplanning coverage estimates. Normally distributed interfraction setup uncertainties were applied to 28 plans for localized prostate cancer, with prescribed dose of 79.2 Gy and 10 mm clinical target volume to planning target volume (CTV-to-PTV) margins. Using angular or isotropic sampling techniques, dosimetric margins were determined for the CTV, bladder and rectum, assuming shift invariance of the dose distribution. For angular sampling, DMDs were sampled at fixed angular intervals w (e.g., w = 1 degree, 2 degrees, 5 degrees, 10 degrees, 20 degrees). Isotropic samples were uniformly distributed on the unit sphere resulting in variable angular increments, but were calculated for the same number of sampling directions as angular DMDs, and accordingly characterized by the effective angular increment omega eff. In each direction, the DM was calculated by moving the structure in radial steps of size delta (=0.1, 0.2, 0.5, 1 mm) until the specified isodose was crossed. Coverage estimation accuracy deltaQ was quantified as a function of the sampling parameters omega or omega eff and delta. The

Monitoring bacterial indicators of water quality in a tidally influenced delta: A Sisyphean pursuit.

Science.gov (United States)

Partyka, Melissa L; Bond, Ronald F; Chase, Jennifer A; Atwill, Edward R

2017-02-01

The Sacramento-San Joaquin Delta Estuary (Delta) is the confluence of two major watersheds draining the Western Sierra Nevada mountains into the Central Valley of California, ultimately terminating into San Francisco Bay. We sampled 88 sites once a month for two years (2006-2008) over 87 separate sampling events for a total of 1740 samples. Water samples were analyzed for fecal indicator bacteria (Escherichia coli, enterococci and fecal coliforms), and 53 other physiochemical, land use, and environmental characteristics. The purpose of the study was to create a baseline of microbial water quality in the Delta and to identify various factors (climatic, land use, tidal, etc.) that were associated with elevated concentrations of indicator bacteria. Fecal indicator bacteria generally had weak to modest relationships to environmental conditions; the strength and direction of which varied for each microbial indicator, drainage region, and across seasons. Measured and unmeasured, site-specific effects accounted for large portions of variance in model predictions (ρ=0.086 to 0.255), indicating that spatial autocorrelation was a major component of water quality outcomes. The effects of tidal cycling and lack of connectivity between waterways and surrounding landscapes likely contributed to the lack of association between local land uses and microbial outcomes, though weak associations may also be indicative of mismatched spatiotemporal scales. The complex nature of this system necessitates continued monitoring and regular updates to statistical models designed to predict microbial water quality. Copyright © 2016 Elsevier B.V. All rights reserved.

Late quaternary evolution of the Orinoco Delta, Venezuela

Science.gov (United States)

Warne, A.G.; Guevara, E.H.; Aslan, A.

2002-01-01

The modern Orinoco Delta is the latest of a series of stacked deltas that have infilled the Eastern Venezuelan Basin (EVB) since the Oligocene. During the late Pleistocene sea-level lowstand (20,000 to 16,000 yrs BP), bedrock control points at the position of the present delta apex prevented the river channel from incising as deeply as many other major river systems. Shallow seismic data indicate that the late Pleistocene Orinoco incised into the present continental shelf, where it formed a braided-river complex that transported sediment to a series of shelf-edge deltas. As sea level rose from 16,000 to 9,500 yrs BP, the Orinoco shoreline shifted rapidly landward, causing shallow-marine waves and currents to form a widespread transgressive sand unit. Decelerating sea-level rise and a warmer, wetter climate during the early Holocene (9,500 to 6,000 yrs BP) induced delta development within the relatively quiet-water environment of the EVB embayment. Sea level approached its present stand in the middle Holocene (6,000 to 3,000 yrs BP), and the Orinoco coast prograded, broadening the delta plain and infilling the EVB embayment. Significant quantities of Amazon sediment began to be transported to the Orinoco coast by littoral currents. Continued progradation in the late Holocene caused the constriction at Boca de Serpientes to alter nearshore and shelf hydrodynamics and subdivide the submarine delta into two distinct areas: the Atlantic shelf and the Gulf of Paria. The increased influence of littoral currents along the coast promoted mudcape development. Because most of the water and sediment were transported across the delta plain through the Rio Grande distributary in the southern delta, much of the central and northwestern delta plain became sediment starved, promoting widespread accumulation of peat deposits. Human impacts on the delta are mostly associated with the Volca??n Dam on Can??o Manamo. However, human activities have had relatively little effect on the

Water and nitrogen conditions affect the relationships of Delta13C and Delta18O to gas exchange and growth in durum wheat.

Science.gov (United States)

Cabrera-Bosquet, Llorenç; Molero, Gemma; Nogués, Salvador; Araus, José Luis

2009-01-01

Whereas the effects of water and nitrogen (N) on plant Delta(13)C have been reported previously, these factors have scarcely been studied for Delta(18)O. Here the combined effect of different water and N regimes on Delta(13)C, Delta(18)O, gas exchange, water-use efficiency (WUE), and growth of four genotypes of durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.] cultured in pots was studied. Water and N supply significantly increased plant growth. However, a reduction in water supply did not lead to a significant decrease in gas exchange parameters, and consequently Delta(13)C was only slightly modified by water input. Conversely, N fertilizer significantly decreased Delta(13)C. On the other hand, water supply decreased Delta(18)O values, whereas N did not affect this parameter. Delta(18)O variation was mainly determined by the amount of transpired water throughout plant growth (T(cum)), whereas Delta(13)C variation was explained in part by a combination of leaf N and stomatal conductance (g(s)). Even though the four genotypes showed significant differences in cumulative transpiration rates and biomass, this was not translated into significant differences in Delta(18)O(s). However, genotypic differences in Delta(13)C were observed. Moreover, approximately 80% of the variation in biomass across growing conditions and genotypes was explained by a combination of both isotopes, with Delta(18)O alone accounting for approximately 50%. This illustrates the usefulness of combining Delta(18)O and Delta(13)C in order to assess differences in plant growth and total transpiration, and also to provide a time-integrated record of the photosynthetic and evaporative performance of the plant during the course of crop growth.

Initial isotopic geochemistry ({delta} 18 O, {delta} D) of fluids from wells of the Los Humeros, Pue., geothermal field; Geoquimica isotopica ({delta} 18 O, {delta} D) inicial de fluidos de pozos del campo geotermico de Los Humeros, Pue.

Energy Technology Data Exchange (ETDEWEB)

Barragan Reyes, Rosa Maria; Arellano Gomez, Victor Manuel [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Cuernavaca, Morelos (Mexico)]. E-mail: rmb@iie.org.mx; Ramirez Montes, Miguel; Tovar Aguado, Rigoberto [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)

2010-01-15

Isotopic data ({delta} 18 O, {delta} D) from fluids from production wells at the Los Humeros, Pue., geothermal field were analyzed to investigate the possible origin of these fluids and the dominant processes of the reservoir at its initial state. According to pre-exploitation data, it is suggested the Los Humeros reservoir fluids are made of a mixture of meteoric water of very light isotopic composition (paleo-fluids) and andesitic water. The relationship {delta} D vs {delta} 18 O from pre-exploitation data indicates the produced fluids are composed of a mixture of (at least) two fluids with distinct isotopic compositions. At the more enriched end of the mixing relationship are the isotopic compositions of the wells H-23 and H-18 (located in the southern area of the field), while the lighter fluids were found in well H-16 (originally) and then in well H-16 (repaired). It was found that the liquid phases of deep wells are more enriched in {delta} 18 O while the shallow wells present lower values, suggesting a convection process at the initial state. Based on this isotopic profile, it is considered that even the production depths of the wells H-1, H-12 and H-16 (repaired) are just about the same, but their respective isotopic compositions are quite different. The {delta} 18 O value for well H-16 (repaired) seems to be that of condensate steam, while the corresponding values for wells H-1 and H-12 fall within the value interval of the deep wells (H-23). This suggests wells H-1 and H-12 are collecting very deep fluids enriched in {delta} 18 O. These results could be useful in creating a conceptual model of the reservoir. [Spanish] Se analizaron datos isotopicos ({delta}18 O, {delta}D) de los fluidos de pozos productores del campo geotermico de Los Humeros, Pue., para investigar el posible origen de los fluidos asi como los procesos dominantes del yacimiento en su estado inicial. De acuerdo con datos previos a la explotacion, se plantea que los fluidos del yacimiento

Conceptualizing delta forms and processes in Arctic coastal environments

DEFF Research Database (Denmark)

Bendixen, Mette; Kroon, Aart

2017-01-01

Climate warming in the Arctic directly causes two opposite changes in Arctic coastal systems: increased melt-water discharge through rivers induces extra influx of sediments and extended open water season increases wave impact which reworks and erodes the shores. A shoreline change analysis along...... and popped up as hotspots. The Tuapaat delta and Skansen delta showed large progradation rates (1.5 and 7m/yr) and migration of the adjacent barriers and spits. The dynamic behavior at the delta mouths was mainly caused by classic delta channel lobe switching at one delta (Tuapaat), and by a breach...... of the fringing spit at the other delta (Skansen). The longshore and cross-shore transports are responsible for reworking the sediment with a result of migrating delta mouths and adjacent subaqueous mouth bars. Seaward progradation of the deltas is limited due to the steep nature of the bathymetry in Disko Bay...

Auditory stream segregation using amplitude modulated bandpass noise

Directory of Open Access Journals (Sweden)

Yingjiu eNie

2015-08-01

Full Text Available The purpose of this study was to investigate the roles of spectral overlap and amplitude modulation (AM rate for stream segregation for noise signals, as well as to test the build-up effect based on these two cues. Segregation ability was evaluated using an objective paradigm with listeners’ attention focused on stream segregation. Stimulus sequences consisted of two interleaved sets of bandpass noise bursts (A and B bursts. The A and B bursts differed in spectrum, AM-rate, or both. The amount of the difference between the two sets of noise bursts was varied. Long and short sequences were studied to investigate the build-up effect for segregation based on spectral and AM-rate differences. Results showed the following: 1. Stream segregation ability increased with greater spectral separation. 2. Larger AM-rate separations were associated with stronger segregation abilities. 3. Spectral separation was found to elicit the build-up effect for the range of spectral differences assessed in the current study. 4. AM-rate separation interacted with spectral separation suggesting an additive effect of spectral separation and AM-rate separation on segregation build-up. The findings suggest that, when normal-hearing listeners direct their attention toward segregation, they are able to segregate auditory streams based on reduced spectral contrast cues that vary by the amount of spectral overlap. Further, regardless of the spectral separation they were able to use AM-rate difference as a secondary/weaker cue. Based on the spectral differences, listeners can segregate auditory streams better as the listening duration is prolonged—i.e. sparse spectral cues elicit build-up segregation; however, AM-rate differences only appear to elicit build-up when in combination with spectral difference cues.

Delta-ray spectroscopy of quasi-atoms

International Nuclear Information System (INIS)

Kozhuharov, C.

1983-01-01

The spectroscopy of high energy delta-rays, emitted in collisions of very heavy ions, is studied. The ''orange''-type beta-spectrometer and the achromatic electron channel are the experimental setups. Delta ray production probabilities are studied as a function of the distance of closest approach R /SUB min/ or the impact parameter b. Coulomb ionization, ion trajectory, scaling laws, double differential cross sections, and K-X-rays information is extracted from the experiment. The dependence of delta-ray emission on the united charge number Z /SUB u/ is discussed. Asymmetric collision systems with Z x alpha approx. = 1 (delta ray spectrum from Pb→Sn collisions) are studied. Finally, very heavy collisions, such as 208 Pb + 208 Pb collisions at bombarding energy fas below the Coulomb barrier are touched upon

Multimode delta-E effect magnetic field sensors with adapted electrodes

Energy Technology Data Exchange (ETDEWEB)

Zabel, Sebastian; Fichtner, Simon; Kirchhof, Christine; Quandt, Eckhard; Faupel, Franz, E-mail: ff@tf.uni-kiel.de [Faculty of Engineering, Institute for Materials Science, Kiel University, Kaiserstraße 2, 24143 Kiel (Germany); Reermann, Jens; Schmidt, Gerhard [Faculty of Engineering, Institute for Electrical Engineering, Kiel University, Kaiserstraße 2, 24143 Kiel (Germany); Wagner, Bernhard [Fraunhofer Institute for Silicon Technology ISIT, Fraunhoferstraße 1, 25524 Itzehoe (Germany)

2016-05-30

We present an analytical and experimental study on low-noise piezoelectric thin film resonators that utilize the delta-E effect of a magnetostrictive layer to measure magnetic fields at low frequencies. Calculations from a physical model of the electromechanical resonator enable electrode designs to efficiently operate in the first and second transversal bending modes. As predicted by our calculations, the adapted electrode design improves the sensitivity by a factor of 6 and reduces the dynamic range of the sensor output by 16 dB, which significantly eases the requirements on readout electronics. Magnetic measurements show a bandwidth of 100 Hz at a noise level of about 100 pTHz{sup −0.5}.

[Characterizing spatial patterns of NO(x), SO2 and O3 in Pearl River Delta by passive sampling].

Science.gov (United States)

Zhao, Yang; Shao, Min; Wang, Chen; Wang, Bo-Guang; Lu, Si-Hua; Zhong, Liu-Ju

2011-02-01

Concentrations of NO(x), SO2 and O3 were measured by passive sampling within 200km x 200km grid in Pearl River Delta (PRD). Sampling period was two weeks in November, 2009. Spatial distributions of NO(x), SO2 and O3 were obtained by Kriging interpolation method. The results were compared with emission inventories and modeling results. The transportations of O3 were evaluated by using backward trajectories of air parcels. During the sampling period, the mean concentrations of NO(x), SO2 and O3 were 75.9 microg/m3, 37.3 microg/m3 and 36.2 microg/m3, respectively. And the highest concentrations of NO(x), SO2 and O3 were 195.7 microg/m3, 95.9 microg/m3 and 81.8 microg/m3. Comparing with routine measurements from the regional monitoring network in PRD, the results by passive method were 18.6%, 33.5% and 37.5% lower for NO(x), SO2 and O3, respectively. The spatial patterns demonstrated that higher NO(x) concentrations often appeared in cities such as Guangzhou, Foshan and Shenzhen. SO2 concentrations were higher in west and lower in east. High SO2 concentrations are mainly from emission of power plants and industrial sources. Concentrations of O3 showed the highest levels in the south of PRD. Backward trajectory analysis for higher ozone areas indicated that 53% of the air masses were from the region with high concentration of NO(x). The horizontal transportation caused higher ozone in the south while lower in north in PRD.

Adaptive delta management : Roots and branches

NARCIS (Netherlands)

Timmermans, J.S.; Haasnoot, M.; Hermans, L.M.; Kwakkel, J.H.; Rutten, M.M.; Thissen, W.A.H.

2015-01-01

Deltas are generally recognized as vulnerable to climate change and therefore a salient topic in adaptation science. Deltas are also highly dynamic systems viewed from physical (erosion, sedimentation, subsidence), social (demographic), economic (trade), infrastructures (transport, energy,

Adaptive Delta Management : Roots and Branches

NARCIS (Netherlands)

Timmermans, Jos; Haasnoot, Marjolijn; Hermans, Leon; Kwakkel, Jan H.; Rutten, Maarten; Thissen, Wil A.H.; Mynett, Arthur

2015-01-01

Deltas are generally recognized as vulnerable to climate change and therefore a salient topic in adaptation science. Deltas are also highly dynamic systems viewed from physical (erosion, sedimentation, subsidence), social (demographic), economic (trade), infrastructures (transport, energy,

Urvina Bay, Galapagos Coral Radiocarbon (delta 14C) Data for 1956 to 1982

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Urvina Bay coral radiocarbon (14C) timeseries. (90 deg W, 0.5 deg S) Coral radiocarbon (Delta-14C) on untreated, low-speed drilled samples. Precision is +/- 4 per...

Evaluation of the Accuracy of NASS/CDS Delta-V Estimates from the Enhanced WinSmash Algorithm

Science.gov (United States)

Hampton, Carolyn E.; Gabler, Hampton C.

2010-01-01

The National Automotive Sampling System / Crashworthiness Data System (NASS/CDS) uses the WinSmash program to reconstruct changes in vehicle velocity for real world crashes. Vehicle change in velocity, or delta-V, is a measure of crash severity and a predictor of injury risk. Earlier studies have demonstrated that WinSmash 2.42 underestimated the delta-V by 23% on average with the use of categorical stiffness values for vehicles identified as a source of error. An enhanced version of WinSmash, WinSmash 2008, was developed to employ vehicle specific stiffness values whenever possible. A total of 478 General Motors vehicles equipped with event data recorders (EDRs) and involved in real-world crashes were collected from years 2000 – 2008 of the NASS/CDS database and the delta-V was computed using the enhanced WinSmash. All vehicles were involved in frontal impacts. The enhanced reconstruction algorithm reduced the underestimation of delta-V from 23% to 13% on average for all vehicles. Delta-V estimates for cars only were greatly improved but still understated by 16% on average. Less than 5% error in delta-V was observed for pickup trucks and utility vehicles. The amount of structural overlap for the vehicle and investigator confidence in the reconstruction continued to have an effect on accuracy. No difference in average delta-V was observed when using either updated categorical stiffness values or vehicle specific stiffness values. The changes in WinSmash delta-Vs have important policy implications for NHTSA as the NASS/CDS delta-Vs are the basis for traffic and safety regulations as well as the speeds for vehicular crash testing and costs/benefits analyses. PMID:21050607

delta 6 Hexadecenoic acid is synthesized by the activity of a soluble delta 6 palmitoyl-acyl carrier protein desaturase in Thunbergia alata endosperm.

Science.gov (United States)

Cahoon, E B; Cranmer, A M; Shanklin, J; Ohlrogge, J B

1994-11-04

delta 6 Hexadecenoic acid (16:1 delta 6) composes more than 80% of the seed oil of Thunbergia alata. Studies were conducted to determine the biosynthetic origin of the double bond of this unusual fatty acid. Assays of fractions of developing T. alata seed endosperm with [1-14C]palmitoyl (16:0)-acyl carrier protein (ACP) revealed the presence of a soluble delta 6 desaturase activity. This activity was greatest when 16:0-ACP was provided as a substrate, whereas no desaturation of the coenzyme A ester of this fatty acid was detected. In addition, delta 6 16:0-ACP desaturase activity in T. alata endosperm extracts was dependent on the presence of ferredoxin and molecular oxygen and was stimulated by catalase. To further characterize this enzyme, a cDNA encoding a diverged acyl-ACP desaturase was isolated from a T. alata endosperm cDNA library using polymerase chain reaction with degenerate oligonucleotides corresponding to conserved amino acid sequences in delta 9 stearoyl (18:0)- and delta 4 16:0-ACP desaturases. The primary structure of the mature peptide encoded by this cDNA shares 66% identity with the mature castor delta 9 18:0-ACP desaturase and 57% identity with the mature coriander delta 4 16:0-ACP desaturase. Extracts of Escherichia coli that express the T. alata cDNA catalyzed the delta 6 desaturation of 16:0-ACP. These results demonstrate that 16:1 delta 6 in T. alata endosperm is formed by the activity of a soluble delta 6 16:0-ACP desaturase that is structurally related to the delta 9 18:0- and delta 4 16:0-ACP desaturases. Implications of this work to an understanding of active site structures of acyl-ACP desaturases are discussed.

Migration in Vulnerable Deltas: A Research Strategy

Science.gov (United States)

Hutton, C.; Nicholls, R. J.; Allan, A.

2015-12-01

C. Hutton1, & R. J. Nicholls1, , 1 University of Southampton, University Road, Southampton, Hampshire, United Kingdom, SO17 1BJ. cwh@geodata. soton.ac.ukAbstractGlobally, deltas contain 500 million people and with rising sea levels often linked to large number of forced migrants are expected in the coming century. However, migration is already a major process in deltas, such as the growth of major cities such as Dhaka and Kolkata. Climate and environmental change interacts with a range of catchment and delta level drivers, which encompass a nexus of sea-level rise, storms, freshwater and sediment supply from the catchment, land degradation, subsidence, agricultural loss and socio-economic stresses. DECCMA (Deltas, Vulnerability and Climate Change: Migration and Adaptation/CARRIA) is investigating migration in the Ganges-Brahmaputra-Meghna (GBM), Mahanadi and Volta Deltas, including the influence of climate change. The research will explore migration from a range of perspectives including governance and stakeholder analysis, demographic analysis, household surveys of sending and receiving areas, macro-economic analysis, and hazards and hotspot analysis both historically and into the future. Migration under climate change will depend on other adaptation in the deltas and this will be examined. Collectively, integrated analysis will be developed to examine migration, other adaptation and development pathways with a particular focus on the implications for the poorest. This will require the development of input scenarios, including expert-derived exogenous scenarios (e.g., climate change) and endogenous scenarios of the delta developed in a participatory manner. This applied research will facilitate decision support methods for the development of deltas under climate change, with a focus on migration and other adaptation strategies.

Upper-division student difficulties with the Dirac delta function

Directory of Open Access Journals (Sweden)

Bethany R. Wilcox

2015-03-01

Full Text Available The Dirac delta function is a standard mathematical tool that appears repeatedly in the undergraduate physics curriculum in multiple topical areas including electrostatics, and quantum mechanics. While Dirac delta functions are often introduced in order to simplify a problem mathematically, students still struggle to manipulate and interpret them. To characterize student difficulties with the delta function at the upper-division level, we examined students’ responses to traditional exam questions and a standardized conceptual assessment, and conducted think-aloud interviews. Our analysis was guided by an analytical framework that focuses on how students activate, construct, execute, and reflect on the Dirac delta function in the context of problem solving in physics. Here, we focus on student difficulties using the delta function to express charge distributions in the context of junior-level electrostatics. Common challenges included invoking the delta function spontaneously, translating a description of a charge distribution into a mathematical expression using delta functions, integrating 3D or non-Cartesian delta function expressions, and recognizing that the delta function can have units. We also briefly discuss implications of these difficulties for instruction.

Delta-nucleus dynamics: proceedings of symposium

Energy Technology Data Exchange (ETDEWEB)

Lee, T.S.H.; Geesaman, D.F.; Schiffer, J.P. (eds.)

1983-10-01

The appreciation of the role in nuclear physics of the first excited state of the nucleon, the delta ..delta..(1232), has grown rapidly in the past decade. The delta resonance dominates nuclear reactions induced by intermediate energy pions, nucleons, and electromagnetic probes. It is also the most important non-nucleonic degree of freedom needed to resolve many fundamental problems encountered in the study of low-energy nuclear phenomena. Clearly, a new phase of nuclear physics has emerged and conventional thinking must be extended to account for this new dimension of nuclear dynamics. The most challenging problem we are facing is how a unified theory can be developed to describe ..delta..-nucleus dynamics at all energies. In exploring this new direction, it is important to have direct discussions among researchers with different viewpoints. Separate entries were prepared for the 49 papers presented. (WHK)

On the origin of delta spots

International Nuclear Information System (INIS)

Tang, F.

1983-01-01

Mount Wilson sunspot drawings from 1966 through 1980 were used in conjunction with Hα filtergrams from Big Bear Solar Observatory to examine the origin of delta spots, spots with bipolar umbrae within one penumbra. Of the six cases we studied, five were formed by the union of non-paired spots. They are either shoved into one another by two neighboring growing bipoles or by a new spot born piggy-back style on an existing spot of opposite polarity. Proper motions of the growing spots take on curvilinear paths around one another to avoid a collision. This is the shear motion observed in delta spots (Tanaka, 1979). In the remaining case, the delta spot was formed by spots that emerged as a pair. Our findings indicate no intrinsic differences in the formation or the behavior between delta spots of normal magnetic configuration. (orig.)

The Role of Reactive Iron in Organic Carbon Burial of the Wax Lake Delta, Louisiana

Science.gov (United States)

Bianchi, T. S.; Shields, M. R.; Gelinas, Y.; Allison, M. A.; Twilley, R.

2016-02-01

Deltaic systems are responsible for 41% of the total organic carbon buried on continental shelves (Smith et al., 2015). Furthermore, 21.5 ± 8.6% of the organic carbon in marine sediments is reported to be associated to reactive iron phases (Lalonde et al., 2012). Here, we examine the role of reactive iron in preserving organic carbon across a chronosequence in deltaic soils/sediments of the Wax Lake Delta, Louisiana. This prograding delta is part of the youngest subdelta of the Mississippi River Delta and serves as a model for deltas in an active progradational stage. We report the proportion, δ13C, lignin phenol content, and fatty acid content of organic carbon associated to iron in three unique environments along the delta topset. We found that over 15 % of the organic carbon in the top 0.5 meters was associated to reactive iron phases at our sampling locations. However, this amount varied between the mudflat, meadow, and canopy dominated sites. Moreover, the type of binding shifts from 1:1 sorption in the sediment dominated (mudflat) region to chelation/co-precipitation in the more soil-dominated regions. Acidic lignin phenols are preferentially sorbed in the mudflat region, which likely occurs pre-depositionally. These results add to our knowledge of the carbon burial processes in young deltas and present new questions about the selective preservation of organic compounds in deltaic sediments.

Holocene evolution of the western Orinoco Delta, Venezuela

Science.gov (United States)

Aslan, A.; White, W.A.; Warne, A.G.; Guevara, E.H.

2003-01-01

The pristine nature of the Orinoco Delta of eastern Venezuela provides unique opportunities to study the geologic processes and environments of a major tropical delta. Remote-sensing images, shallow cores, and radiocarbon-dating of organic remains form the basis for describing deltaic environments and interpreting the Holocene history of the delta. The Orinoco Delta can be subdivided into two major sectors. The southeast sector is dominated by the Rio Grande-the principal distributary-and complex networks of anastomosing fluvial and tidal channels. The abundance of siliciclastic deposits suggests that fluvial processes such as over-bank flooding strongly influence this part of the delta. In contrast, the northwest sector is represented by few major distributaries, and overbank sedimentation is less widespread relative to the southeast sector. Peat is abundant and occurs in herbaceous and forested swamps that are individually up to 200 km2 in area. Northwest-directed littoral currents transport large volumes of suspended sediment and produce prominent mudcapes along the northwest coast. Mapping of surface sediments, vegetation, and major landforms identified four principal geomorphic systems within the western delta plain: (1) distributary channels, (2) interdistributary flood basins, (3) fluvial-marine transitional environments, and (4) marine-influenced coastal environments. Coring and radiocarbon dating of deltaic deposits show that the northern delta shoreline has prograded 20-30 km during the late Holocene sea-level highstand. Progradation has been accomplished by a combination of distributary avulsion and mudcape progradation. This style of deltaic progradation differs markedly from other deltas such as the Mississippi where distributary avulsion leads to coastal land loss, rather than shoreline progradation. The key difference is that the Orinoco Delta coastal zone receives prodigious amounts of sediment from northwest-moving littoral currents that transport

Breed distribution of the ABCB1-1Delta (multidrug sensitivity) polymorphism among dogs undergoing ABCB1 genotyping.

Science.gov (United States)

Mealey, Katrina L; Meurs, Kathryn M

2008-09-15

To evaluate the breed distribution of the ABCB1-1Delta polymorphism in a large number of dogs in North America, including dogs of several herding breeds in which this polymorphism has been detected and other breeds in which this polymorphism has not yet been identified. Cross-sectional study. 5,368 dogs from which buccal swab samples were collected for purposes of ABCB1 genotyping. From May 1, 2004, to September 30, 2007, DNA specimens derived from buccal swab samples collected from 5,368 dogs underwent ABCB1 genotyping. These data were reviewed, and results for each dog were recorded in a spreadsheet, along with the dog's breed. The genotypes for each breed were tallied by use of a sorting function. The ABCB1-1Delta allele was identified in 9 breeds of dogs and in many mixed-breed dogs. Breeds that had the ABCB1-1Delta allele included Collie, Longhaired Whippet, Australian Shepherd (standard and miniature), Shetland Sheepdog, Old English Sheepdog, Border Collie, Silken Windhound, and German Shepherd Dog (a breed in which this mutation had not been detected previously). The ABCB1-1Delta polymorphism is associated with increased susceptibility to many adverse drug reactions and with suppression of the hypothalamic-pituitary-adrenal axis and is present in many herding breeds of dog. Veterinarians should be familiar with the breeds that have the ABCB1-1Delta polymorphism to make appropriate pharmacologic choices for these patients.

Metamaterial composite bandpass filter with an ultra-broadband rejection bandwidth of up to 240 terahertz

DEFF Research Database (Denmark)

Strikwerda, Andrew; Zalkovskij, Maksim; Lorenzen, Dennis Lund

2014-01-01

We present a metamaterial, consisting of a cross structure and a metal mesh filter, that forms a composite with greater functional bandwidth than any terahertz (THz) metamaterial to date. Metamaterials traditionally have a narrow usable bandwidth that is much smaller than common THz sources......, such as photoconductive antennas and difference frequency generation. The composite structure shown here expands the usable bandwidth to exceed that of current THz sources. To highlight the applicability of this combination, we demonstrate a series of bandpass filters with only a single pass band, with a central...... frequency (f) that is scalable from 0.86–8.51 THz, that highly extinguishes other frequencies up to >240 THz. The performance of these filters is demonstrated in experiment, using both air biased coherent detection and a Fourier transform infrared spectrometer (FTIR), as well as in simulation. We present...

Hot deformation behavior of delta-processed superalloy 718

Energy Technology Data Exchange (ETDEWEB)

Wang, Y., E-mail: wangyanhit@yahoo.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); School of Aeronautics and Astronautics, Central South University, Changsha 410083 (China); Shao, W.Z.; Zhen, L.; Zhang, B.Y. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2011-03-25

Research highlights: {yields} The peak stress for hot deformation can be described by the Z parameter. {yields} The grain size of DRX was inversely proportional to the Z parameter. {yields} The dissolution of {delta} phases was greatly accelerated under hot deformation. {yields}The {delta} phase stimulated nucleation can serve as the main DRX mechanism. - Abstract: Flow stress behavior and microstructures during hot compression of delta-processed superalloy 718 at temperatures from 950 to 1100 deg. C with strain rates of 10{sup -3} to 1 s{sup -1} were investigated by optical microscopy (OM), electron backscatter diffraction (EBSD) technique and transmission electron microscopy (TEM). The relationship between the peak stress and the deformation conditions can be expressed by a hyperbolic-sine type equation. The activation energy for the delta-processed superalloy 718 is determined to be 467 kJ/mol. The change of the dominant deformation mechanisms leads to the decrease of stress exponent and the increase of activation energy with increasing temperature. The dynamically recrystallized grain size is inversely proportional to the Zener-Hollomon (Z) parameter. It is found that the dissolution rate of {delta} phases under hot deformation conditions is much faster than that under static conditions. Dislocation, vacancy and curvature play important roles in the dissolution of {delta} phases. The main nucleation mechanisms of dynamic recrystallization (DRX) for the delta-processed superalloy 718 include the bulging of original grain boundaries and the {delta} phase stimulated DRX nucleation, which is closely related to the dissolution behavior of {delta} phases under certain deformation conditions.

Primary production in the Delta: Then and now

Science.gov (United States)

Cloern, James E.; Robinson, April; Richey, Amy; Grenier, Letitia; Grossinger, Robin; Boyer, Katharyn E.; Burau, Jon; Canuel, Elizabeth A.; DeGeorge, John F.; Drexler, Judith Z.; Enright, Chris; Howe, Emily R.; Kneib, Ronald; Mueller-Solger, Anke; Naiman, Robert J.; Pinckney, James L.; Safran, Samuel M.; Schoellhamer, David H.; Simenstad, Charles A.

2016-01-01

To evaluate the role of restoration in the recovery of the Delta ecosystem, we need to have clear targets and performance measures that directly assess ecosystem function. Primary production is a crucial ecosystem process, which directly limits the quality and quantity of food available for secondary consumers such as invertebrates and fish. The Delta has a low rate of primary production, but it is unclear whether this was always the case. Recent analyses from the Historical Ecology Team and Delta Landscapes Project provide quantitative comparisons of the areal extent of 14 habitat types in the modern Delta versus the historical Delta (pre-1850). Here we describe an approach for using these metrics of land use change to: (1) produce the first quantitative estimates of how Delta primary production and the relative contributions from five different producer groups have been altered by large-scale drainage and conversion to agriculture; (2) convert these production estimates into a common currency so the contributions of each producer group reflect their food quality and efficiency of transfer to consumers; and (3) use simple models to discover how tidal exchange between marshes and open water influences primary production and its consumption. Application of this approach could inform Delta management in two ways. First, it would provide a quantitative estimate of how large-scale conversion to agriculture has altered the Delta's capacity to produce food for native biota. Second, it would provide restoration practitioners with a new approach—based on ecosystem function—to evaluate the success of restoration projects and gauge the trajectory of ecological recovery in the Delta region.

Otolith analysis of pre-restoration habitat use by Chinook salmon in the delta-flats and nearshore regions of the Nisqually River Estuary

Science.gov (United States)

Lind-Null, Angie; Larsen, Kim

2010-01-01

The Nisqually Fall Chinook population is one of 27 salmon stocks in the Puget Sound (Washington) evolutionarily significant unit listed as threatened under the federal Endangered Species Act (ESA). Extensive restoration of the Nisqually River delta ecosystem is currently taking place to assist in recovery of the stock as juvenile Fall Chinook salmon are dependent on the estuary. A pre-restoration baseline that includes the characterization of life history strategies, estuary residence times, growth rates, and habitat use is needed to evaluate the potential response of hatchery and natural origin Chinook salmon to restoration efforts and to determine restoration success. Otolith analysis was selected as a tool to examine Chinook salmon life history, growth, and residence in the Nisqually River estuary. Previously funded work on samples collected in 2004 (marked and unmarked) and 2005 (unmarked only) partially established a juvenile baseline on growth rates and length of residence associated with various habitats (freshwater, forested riverine tidal, emergent forested transition, estuarine emergent marsh, delta-flats and nearshore). However, residence times and growth rates for the delta-flats (DF) and nearshore (NS) habitats have been minimally documented due to small sample sizes. The purpose of the current study is to incorporate otolith microstructural analysis using otoliths from fish collected within the DF and NS habitats during sampling years 2004-08 to increase sample size and further evaluate between-year variation in otolith microstructure. Our results from this analysis indicated the delta-flats check (DFCK) on unmarked and marked Chinook samples in 2005-08 varied slightly in appearance from that seen on samples previously analyzed only from 2004. A fry migrant life history was observed on otoliths of unmarked Chinook collected in 2005, 2007, and 2008. Generally, freshwater mean increment width of unmarked fish, on average, was smaller compared to marked

Stable carbon isotopic composition of petroleum condensate from the nile Delta and western Sinai fields and its correlation with crude oils and natural gases

International Nuclear Information System (INIS)

Abd El Samie, S.G.

2006-01-01

Twenty six of condensate samples from three provinces; Abu Madi (onshore NE Delta), Port Fouad (offshore) in the Mediterranean sea, and Abu Rudeis areas, were analyzed and correlated to the Nile Delta, Gulf of Suez and western desert crude oils. Different isotopic results were obtained specifying each group that reflects the depositional environment, temperature gradient and maturation level of organic matter in each area. The mean isotopic results (av. σ 13 C) of Abu Madi condensate samples reached about -26.41 close to the values of the western desert total oil, indicating thermal graded fluid and depositional environment very close to the western desert in hydrocarbon type (mainly of terrestrial sources), thermal condition and long time of deposition. The offshore Port Fouad condensate samples have relatively wide range of σ 13 C between -27.24 to -24.03% representing mixing between marine and terrestrial hydrocarbons migrated from the near shore areas of the Nile Delta to the Mediterranean sea sub-basins. Abu Rudeis condensate samples have the isotopic signature of σ 13 C = -30.09 to -29.05% close to the Gulf of Suez crude oil samples which reflect the deposition under mainly marine environment of the Red Sea basins. As petroleum condensates considered as moderate compounds between oils and gases, their isotopic contents refer to the produced oil or gas from the same sample. Though condensate samples are correlated with gases produced from the Nile Delta. Based on carbon isotopic values of methane and light gas fractions, the produced gases from the Nile Delta could be generated mainly from terrestrial sources enriched in σ 13 C of C 2 +. These gases are classified according to the thermogenic origin enriched in σ 13 C C H4 in the Nile Delta onshore fields in Abu Madi formation. In shallower formations (Kafr El Sheikh formation), isotopically light gases were found in the NE direction and appeared to be of biogenic source, whereas mixed gases were found in

Casscf/ci Calculations for First Row Transition Metal Hydrides - the TIH(4-PHI), VH(5-DELTA), CRH(6-SIGMA-PLUS), MNH(7-SIGMA-PLUS), FEH(4,6-DELTA) and NIH(2-DELTA) States

Science.gov (United States)

Walch, S. P.; Bauschlicher, C. W., Jr.

1983-04-01

Calculations are performed for the predicted ground states of TiH(4-phi), VH(5-delta), CrH(6-sigma-plus), MnH(7-sigma-plus), Fett(4,6-delta) and NiH(2-delta). For FeH both the 6-delta and 4-delta states are studied, since both are likely candidates for the ground state. The ground state symmetries are predicted based on a combination of atomic coupling arguments and coupling of 4s(2)3d(n) and 4s(1)3d(n+1) terms in the molecular system. Electron correlation is included by a CASSCF/CI (SD) treatment. The CASSCF includes near-degeneracy effects, while correlation of the 3d electrons in included at the CI level.

Multichannel infinite clipping as a form of sampling of speech signals

International Nuclear Information System (INIS)

Guidarelli, G.

1985-01-01

A remarkable improvement of both intelligibility and naturalness of infinitely clipped speech can be achieved by means of a multichannel system in which the speech signal is splitted into several band-pass channels before the clipping and successively reconstructed by summing up the clipped outputs of each channel. A possible explanation of such an improvement is given, founded on the so-called zero-based representation of band limited signals where the zero-crossings sequence is considered as a set of samples of the signal

Empirical P-L-C relations for delta Scuti stars

International Nuclear Information System (INIS)

Gupta, S.K.

1978-01-01

Separate P-L-C relations have been empirically derived by sampling the delta Scuti stars according to their pulsation modes. The results based on these relations have been compared with those estimated from the model based P-L-C relations and the other existing empirical P-L-C relations. It is found that a separate P-L-C relation for each pulsation mode provides a better correspondence with observations. (Auth.)

Dynamic functional coupling of high resolution EEG potentials related to unilateral internally triggered one-digit movements.

Science.gov (United States)

Urbano, A; Babiloni, C; Onorati, P; Babiloni, F

1998-06-01

Between-electrode cross-covariances of delta (0-3 Hz)- and theta (4-7 Hz)-filtered high resolution EEG potentials related to preparation, initiation. and execution of human unilateral internally triggered one-digit movements were computed to investigate statistical dynamic coupling between these potentials. Significant (P planning, starting, and performance of unilateral movement. The involvement of these cortical areas is supported by the observation that averaged spatially enhanced delta- and theta-bandpassed potentials were computed from the scalp regions where task-related electrical activation of primary sensorimotor areas and supplementary motor area was roughly represented.

Tidal controls on river delta morphology

NARCIS (Netherlands)

Hoitink, A.J.F.; Wang, Z.B.; Vermeulen, B.; Huismans, Y.; Kästner, K.

2017-01-01

River delta degradation has been caused by extraction of natural resources, sediment retention by reservoirs, and sea-level rise. Despite global concerns about these issues, human activity in the world's largest deltas intensifies. Harbour development, construction of flood defences, sand mining and

Tidal controls on river delta morphology

NARCIS (Netherlands)

Hoitink, A.J.F.; Wang, Zhengbing; Vermeulen, B.; Huismans, Y; Kästner, K

River delta degradation has been caused by extraction of natural resources, sediment retention by reservoirs, and sea-level rise. Despite global concerns about these issues, human activity in the world’s largest deltas intensifies. Harbour development, construction of flood defences, sand mining and

Environmental challenges in Nigeria's Delta Region and Agriculture ...

African Journals Online (AJOL)

The paper discussed the environmental challenges in the Niger-Delta region of Nigeria with emphasis on the impacts on agricultural production. It thus discussed the concepts of Niger-Delta, Environmental pollution, Niger-Delta crises and Agriculture. The paper posits that there are positive relationships between these ...

Nitrogen Leaching in Intensive Cropping Systems in Tam Duong District, Red River Delta of Vietnam

OpenAIRE

Trinh, M.V.; Keulen, van, H.; Roetter, R.P.

2010-01-01

The environmental and economic consequences of nitrogen (N) lost in rice-based systems in Vietnam is important but has not been extensively studied. The objective of this study was to quantify the amount of N lost in major cropping systems in the Red River Delta. An experiment was conducted in the Red River Delta of Vietnam, on five different crops including rose, daisy, cabbage, chili, and a rice–rice–maize rotation during 2004 and 2005. Core soil samples were taken periodically in 20-cm inc...

234U/238U and δ87Sr in peat as tracers of paleosalinity in the Sacramento-San Joaquin Delta of California, USA

International Nuclear Information System (INIS)

Drexler, J.Z.; Paces, J.B.; Alpers, C.N.; Windham-Myers, L.; Neymark, L.A.; Bullen, T.D.; Taylor, H.E.

2014-01-01

Highlights: • Concentrations and isotopic values of Sr and U in peat were used to trace paleosalinity. • A three-end-member mixing model was constructed using values from water sources. • Paleosalinity of peat samples was determined relative to that of end members. • δ 87 Sr values were altered during and after the California Gold Rush period. • Oligohaline and freshwater marshes have long existed in the Sacramento-San Joaquin Delta. - Abstract: The purpose of this study was to determine the history of paleosalinity over the past 6000+ years in the Sacramento-San Joaquin Delta (the Delta), which is the innermost part of the San Francisco Estuary. We used a combination of Sr and U concentrations, δ 87 Sr values, and 234 U/ 238 U activity ratios (AR) in peat as proxies for tracking paleosalinity. Peat cores were collected in marshes on Browns Island, Franks Wetland, and Bacon Channel Island in the Delta. Cores were dated using 137 Cs, the onset of Pb and Hg contamination from hydraulic gold mining, and 14 C. A proof of concept study showed that the dominant emergent macrophyte and major component of peat in the Delta, Schoenoplectus spp., incorporates Sr and U and that the isotopic composition of these elements tracks the ambient water salinity across the Estuary. Concentrations and isotopic compositions of Sr and U in the three main water sources contributing to the Delta (seawater, Sacramento River water, and San Joaquin River water) were used to construct a three-end-member mixing model. Delta paleosalinity was determined by examining variations in the distribution of peat samples through time within the area delineated by the mixing model. The Delta has long been considered a tidal freshwater marsh region, but only peat samples from Franks Wetland and Bacon Channel Island have shown a consistently fresh signal (<0.5 ppt) through time. Therefore, the eastern Delta, which occurs upstream from Bacon Channel Island along the San Joaquin River and its

Losses of Sacramento River Chinook Salmon and Delta Smelt to Entrainment in Water Diversions in the Sacramento–San Joaquin Delta

Directory of Open Access Journals (Sweden)

Wim J. Kimmerer

2008-06-01

Full Text Available Pumping at the water export facilities in the southern Sacramento-San Joaquin Delta kills fish at and near the associated fish-salvage facilities. Correlative analyses of salvage counts with population indices have failed to provide quantitative estimates of the magnitude of this mortality. I estimated the proportional losses of Sacramento River Chinook salmon (Oncorhynchus tshawytscha and delta smelt (Hypomesus transpacificus to place these losses in a population context. The estimate for salmon was based on recoveries of tagged smolts released in the upper Sacramento River basin, and recovered at the fish-salvage facilities in the south Delta and in a trawling program in the western Delta. The proportion of fish salvaged increased with export flow, with a mean value around 10% at the highest export flows recorded. Mortality was around 10% if pre-salvage losses were about 80%, but this value is nearly unconstrained. Losses of adult delta smelt in winter and young delta smelt in spring were estimated from salvage data (adults corrected for estimated pre-salvage survival, or from trawl data in the southern Delta (young. These losses were divided by population size and accumulated over the respective seasons. Losses of adult delta smelt were 1–50% (median 15% although the highest value may have been biased upward. Daily losses of larvae and juveniles were 0–8%, and seasonal losses accumulated were 0–25% (median 13%. The effect of these losses on population abundance was obscured by subsequent 50-fold variability in survival from summer to fall.

Displacement waves in La2CuO(4-delta) and La(1.85)Sr(0.15)CuO(4-delta)

Science.gov (United States)

Kajitani, Tsuyoshi; Onozuka, Takashi; Yamaguchi, Yasuo; Hirabayashi, Makoto; Syono, Yasuhiko

1987-11-01

Structural investigation of orthorhombic La2CuO(4-delta) and La(1.85)Sr(0.15)CuO(4-delta) was carried out by means of X-ray and neutron diffraction on the basis of the space group Cmmm. The periodic expansion/contraction type distortion of CuO6 octahedra was found in both orthorhombic compounds. The distortion is nearly one-dimensional in La2CuO(4-delta) but is two-dimensional in La(1.85)Sr(0.15)CuO(4-delta). The existence of a charge-density wave is highly possible in the structures.

Combination of highly nonlinear fiber, an optical bandpass filter, and a Fabry-Perot filter to improve the signal-to-noise ratio of a supercontinuum continuous-wave optical source.

Science.gov (United States)

Nan, Yinbo; Huo, Li; Lou, Caiyun

2005-05-20

We present a theoretical study of a supercontinuum (SC) continuous-wave (cw) optical source generation in highly nonlinear fiber and its noise properties through numerical simulations based on the nonlinear Schrödinger equation. Fluctuations of pump pulses generate substructures between the longitudinal modes that result in the generation of white noise and then in degradation of coherence and in a decrease of the modulation depths and the signal-to-noise ratio (SNR). A scheme for improvement of the SNR of a multiwavelength cw optical source based on a SC by use of the combination of a highly nonlinear fiber (HNLF), an optical bandpass filter, and a Fabry-Perot (FP) filter is presented. Numerical simulations show that the improvement in modulation depth is relative to the HNLF's length, the 3-dB bandwidth of the optical bandpass filter, and the reflection ratio of the FP filter and that the average improvement in modulation depth is 13.7 dB under specified conditions.

First-principles elastic constants and phonons of delta-Pu

DEFF Research Database (Denmark)

Söderlind, P.; Landa, A.; Sadigh, B.

2004-01-01

Elastic constants and zone-boundary phonons of delta-plutonium have been calculated within the density-functional theory. The paramagnetic state of delta-Pu is modeled by disordered magnetism utilizing either the disordered local moment or the special quasirandom structure techniques. The anomalo......Elastic constants and zone-boundary phonons of delta-plutonium have been calculated within the density-functional theory. The paramagnetic state of delta-Pu is modeled by disordered magnetism utilizing either the disordered local moment or the special quasirandom structure techniques....... The anomalously soft C-' as well as a large anisotropy ratio (C-44/C-') of delta-Pu is reproduced by this theoretical model. Also the recently measured phonons for delta-Pu compare relatively well with their theoretical counterpart at the zone boundaries....

Adulteration of honey : relation between microscopic analysis and delta C-13 measurements

NARCIS (Netherlands)

Kerkvliet, JD; Meijer, HAJ

2000-01-01

Upon routine microscopic analysis of some honey samples, parenchyma cells, single rings of ring vessels and epidermal cells are found. These cells originate from the sugar cane stem. We investigated whether there was a relation between these plant fragments and the delta C-13 value of honey. 17

Deltamethrin in sediment samples of the Okavango Delta, Botswana ...

African Journals Online (AJOL)

Analysis of samples for organic matter content showed percentage total organic carbon (% TOC) ranging between 0.19% and 8.21%, with samples collected from the pool having the highest total organic carbon. The concentrations of deltamethrin residues and the % TOC in sediment samples showed a similar trend with ...

Monitoring and modeling the fate of commonly used pesticides in surface water of the Lower Mekong Delta

Science.gov (United States)

van Toan, Pham; Sebesvari, Zita; Loan, Vo Phuong Hong; Renaud, Fabrice

2010-05-01

monitored systematically from August 2008 to August 2009. Methods: Water samples (0.5 L) were collected in borosilicate bottles with Teflon caps, pre-filtered with glass wool (Roth, Germany) and glass fibre filter (Millipore, USA), solid-phase extracted (Phenomenex, C18-E) and quantified using GC-MS (Agilent 6890). For quality assurance samples and blanks were spiked with a surrogate standard (d-HCH). The recovery of the surrogate standard was used to monitor for matrix effects and sample processing errors. Surrogate recovery was evaluated by a recovery standard (Fluoren-d10) spiked to the sample after the extraction. Results: A total of 434 samples (253 samples in Ba Lang, 119 samples in An Long and 62 drinking water samples) were collected from August 2008 to August 2009. In An Long 13 of the 15 target compounds were detected in water samples. Average residue concentrations ranged from 0.01 to 3.96 ?g/l. The fungicide isoprothiolane and the insecticide buprofezin occurred with the highest concentrations (up to 20.77 and 16.53 ?g/l, respectively). In Ba Lang, 12 of the 15 monitored pesticides were detected with an average concentration from 0.01 to 0.30 ?g/l. The fungicide isoprothiolane was detected with highest (up to 12.86 ?g/l). In 70% of all samples more than four different pesticides were detected. Their effect may add up and pose risk to humans and aquatic organisms. In rural areas surface water is frequently used as drinking water source. First results from a sampling program of drinking water indicate that locally used water treatment methods (precipitation with aluminium sulfate followed by boiling) were not appropriate to reduce the pesticide exposure of the consumer. Through evaporation, boiling of drinking water even increased the concentrations of some non-volatile pesticides. References Carvalho, F. P., Villeneuve, J.P., Cattini, C., Tolosa, I., Thuan, D. D., Nhan, D. D., 2008. Agrochemical and polychlorobyphenyl (PCB) residues in the Mekong River delta

Water quality in Danube Delta Lakes: An assessment using benthic macroinvertebrates community

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IBRAM Orhan

2016-12-01

Full Text Available An assessment of the ecological status of selected lakes in the Danube Delta Biosphere Reserve was done based on temporal and spatial variation of macroinvertebrate communities during 2012 and 2013. Macroinvertebrate communities and measures of these communities were evaluated and a baseline characterization of assemblages was determined for the analyzed sites. Each year, three sampling campaigns, one for each ice-free season were organized for data collection. Macroinvertebrate samples have been collected in every lake from three different stations with the use of an Ekmann dredge. The highest taxa richness are recorded in Fortuna and Isac lakes in 2013. Total abundance followed a pattern similar to taxa number with Fortuna and Isac lakes having the highest yearly values (maximum number of individuals – 225 - per sample has been recorded in September 2013, in Isac Lake.Using saprobic index as an indicator of ecological status Isac lake was classifies as moderate and other three lakes, Merhei, Furtuna and Rosu as good ecological status. Lack of correlation between diversity indices and the saprobic values suggests that other assessment methods could be more effective and provide better information than saprobic index does at least for Danube Delta.

Stimulation of accumbal GABAA receptors inhibits delta2-, but not delta1-, opioid receptor-mediated dopamine efflux in the nucleus accumbens of freely moving rats.

Science.gov (United States)

Aono, Yuri; Kiguchi, Yuri; Watanabe, Yuriko; Waddington, John L; Saigusa, Tadashi

2017-11-15

The nucleus accumbens contains delta-opioid receptors that may reduce inhibitory neurotransmission. Reduction in GABA A receptor-mediated inhibition of accumbal dopamine release due to delta-opioid receptor activation should be suppressed by stimulating accumbal GABA A receptors. As delta-opioid receptors are divided into delta2- and delta1-opioid receptors, we analysed the effects of the GABA A receptor agonist muscimol on delta2- and delta1-opioid receptor-mediated accumbal dopamine efflux in freely moving rats using in vivo microdialysis. Drugs were administered intracerebrally through the dialysis probe. Doses of compounds indicate total amount administered (mol) during 25-50min infusions. The delta2-opioid receptor agonist deltorphin II (25.0nmol)- and delta1-opioid receptor agonist DPDPE (5.0nmol)-induced increases in dopamine efflux were inhibited by the delta2-opioid receptor antagonist naltriben (1.5nmol) and the delta1-opioid receptor antagonist BNTX (150.0pmol), respectively. Muscimol (250.0pmol) inhibited deltorphin II (25.0nmol)-induced dopamine efflux. The GABA A receptor antagonist bicuculline (50.0pmol), which failed to affect deltorphin II (25.0nmol)-induced dopamine efflux, counteracted the inhibitory effect of muscimol on deltorphin II-induced dopamine efflux. Neither muscimol (250.0pmol) nor bicuculline (50.0 and 500.0pmol) altered DPDPE (5.0nmol)-induced dopamine efflux. The present results show that reduction in accumbal GABA A receptor-mediated inhibition of dopaminergic activity is necessary to produce delta2-opioid receptor-induced increase in accumbal dopamine efflux. This study indicates that activation of delta2- but not delta1-opioid receptors on the cell bodies and/or terminals of accumbal GABAergic interneurons inhibits GABA release and, accordingly, decreases GABA A receptor-mediated inhibition of dopaminergic terminals, resulting in enhanced accumbal dopamine efflux. Copyright © 2017 Elsevier B.V. All rights reserved.

Tidal modulated flow and sediment flux through Wax Lake Delta distributary channels: Implications for delta development

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K. Hanegan

2015-03-01

Full Text Available In this study, a Delft3D model of the Wax Lake Delta was developed to simulate flow and sediment flux through delta distributary channels. The model was calibrated for tidal constituents as well as velocity and sediment concentration across channel transects. The calibrated model was then used to simulate full spring–neap tidal cycles under constant low flow upstream boundary conditions, with grain size variation in suspended load represented using two sediment fractions. Flow and sediment flux results through distributary channel cross-sections were examined for spatial and temporal variability with the goal of characterizing the role of tides in sediment reworking and delta development. The Wax Lake Delta has prograded through channel extension, river mouth bar deposition, and channel bifurcation. Here we show that tidal modulation of currents influences suspended sand transport, and spatial acceleration through distributary channels at low tides is sufficient to suspend sand in distal reaches during lower flows. The basinward-increasing transport capacity in distributary channels indicates that erosive channel extension could be an important process, even during non-flood events.

Three New Offset {delta}{sup 11}B Isotope Reference Materials for Environmental Boron Isotope Studies

Energy Technology Data Exchange (ETDEWEB)

Rosner, M. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany); IsoAnalysis UG, Berlin (Germany); Vogl, J. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany)

2013-07-15

The isotopic composition of boron is a well established tool in various areas of science and industry. Boron isotope compositions are typically reported as {delta}{sup 11}B values which indicate the isotopic difference of a sample relative to the isotope reference material NIST SRM 951. A significant drawback of all of the available boron isotope reference materials is that none of them covers a natural boron isotope composition apart from NIST SRM 951. To fill this gap of required {delta}{sup 11}B reference materials three new solution boric acid reference materials were produced, which cover 60 per mille of the natural boron isotope variation (-20 to 40 per mille {delta}{sup 11}B) of about 100 per mille . The new reference materials are certified for their {delta}{sup 11}B values and are commercially available through European Reference Materials (http://www.erm-crm.org). The newly produced and certified boron isotope reference materials will allow straightforward method validation and quality control of boron isotope data. (author)

Evaluation of Achievement of Universal Basic Education (UBE) in Delta State

Science.gov (United States)

Osadebe, P. U.

2014-01-01

The study evaluated the objectives of the Universal Basic Education (UBE) programme in Delta State. It considered the extent to which each objective was achieved. A research question on the extent to which the UBE objectives were achieved guided the study. Two hypotheses were tested. A sample of 300 students was randomly drawn through the use of…

In vivo metabolism of (+)-trans-delta-9-tetrahydrocannabinol in the mouse.

Science.gov (United States)

Harvey, D J

1988-01-15

(+)-trans-Delta-9-tetrahydrocannabinol [(+)-delta-9-THC], a biologically inactive isomer of (-)-trans-delta-9-THC, the major psychoactive constituent of cannabis, was administered intraperitoneally to male Charles River CD-1 mice; hepatic metabolites were extracted with ethyl acetate and isolated by chromatography on Sephadex LH-20 in chloroform. The metabolites were converted into trimethylsilyl (TMS), 2H9-TMS and methyl ester/TMS derivatives for examination by gas chromatography/mass spectrometry and additional samples were prepared by reduction of metabolic fractions with lithium aluminium deuteride. Sixteen metabolites were characterized: these were alcohols and carboxylic acids, together with several of their hydroxylated analogues. The major biotransformation pathway was hydroxylation at C(11) to give the major metabolite, followed by oxidation of this compound to a carboxylic acid. Hydroxylated analogues of these two compounds were substituted mainly in the side-chain. Although metabolism was very similar to that of the naturally occurring (-)-isomer as far as positions of substitution were concerned, some differences were observed. These related mainly to the positions of hydroxylation on the side-chain, where 1'-hydroxylation was preferred to hydroxylation at the 2'-position. The major difference in metabolism between the two isomers was that much less oxidation of the 11-hydroxy group to a carboxylic acid occurred and there was less hydroxylation at the 8-position. Thus, 11-hydroxy-(+)-trans-delta-9-THC was the major metabolite and most other metabolites were hydroxylated derivatives of this compound.

Delta Vegetation and Land Use [ds292

Data.gov (United States)

California Natural Resource Agency — Vegetation and land use are mapped for the approximately 725,000 acres constituting the Legal Delta portion of the Sacramento and San Joaquin River Delta area....

Primary Production in the Delta: Then and Now

Directory of Open Access Journals (Sweden)

James E. Cloern

2016-10-01

Full Text Available doi: http://dx.doi.org/10.15447/sfews.2016v14iss3art1To evaluate the role of restoration in the recovery of the Delta ecosystem, we need to have clear targets and performance measures that directly assess ecosystem function. Primary production is a crucial ecosystem process, which directly limits the quality and quantity of food available for secondary consumers such as invertebrates and fish. The Delta has a low rate of primary production, but it is unclear whether this was always the case. Recent analyses from the Historical Ecology Team and Delta Landscapes Project provide quantitative comparisons of the areal extent of 14 habitat types in the modern Delta versus the historical Delta (pre-1850. Here we describe an approach for using these metrics of land use change to: (1 produce the first quantitative estimates of how Delta primary production and the relative contributions from five different producer groups have been altered by large-scale drainage and conversion to agriculture; (2 convert these production estimates into a common currency so the contributions of each producer group reflect their food quality and efficiency of transfer to consumers; and (3 use simple models to discover how tidal exchange between marshes and open water influences primary production and its consumption. Application of this approach could inform Delta management in two ways. First, it would provide a quantitative estimate of how large-scale conversion to agriculture has altered the Delta's capacity to produce food for native biota. Second, it would provide restoration practitioners with a new approach—based on ecosystem function—to evaluate the success of restoration projects and gauge the trajectory of ecological recovery in the Delta region.

Attitudes and beliefs affect frequency of eating out in the Lower Mississippi Delta

Science.gov (United States)

Attitudes and beliefs reflecting cultural values can have a positive or negative influence on eating behaviors. Eating out may negatively affect diet quality through increased fat intake and larger portion sizes. In a representative sample of the Lower Mississippi Delta (LMD) consisting of 1601 Af...

{Delta}{sup 14}C level of annual plants and fossil fuel derived CO{sub 2} distribution across different regions of China

Energy Technology Data Exchange (ETDEWEB)

Xi, X.T.; Ding, X.F.; Fu, D.P. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Zhou, L.P. [Laboratory for Earth Surface Processes, Department of Geography, Peking University, Beijing 100871 (China); Liu, K.X., E-mail: kxliu@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China)

2013-01-15

The {sup 14}C level in annual plants is a sensitive tracer for monitoring fossil fuel derived CO{sub 2} in the atmosphere. Corn leave samples were selected from different regions of China, including high mountains in the Tibetan Plateau, grassland in Inner Mongolia, and inland and coastal cities during the summer of 2010. The {sup 14}C/{sup 12}C ratio of the samples was measured with the NEC compact AMS system at the Institute of Heavy Ion Physics, Peking University. The fossil fuel derived CO{sub 2} was estimated by comparing the measured {Delta}{sup 14}C values of corn leave samples to background atmospheric {Delta}{sup 14}C level. The influences of topography, meteorological conditions and carbon cycling processes on the fossil fuel derived CO{sub 2} concentration are considered when interpreting the data. Our results show a clear association of the low {Delta}{sup 14}C values with regions where human activities are intensive.

Raman scattering, magnetization and magnetotransport study of SrFeO{sub 3-{delta}}, Sr{sub 3}Fe{sub 2}O{sub 7-{delta}} and CaFeO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Damljanovic, Vladimir

2008-12-16

In this thesis we have determined the Raman spectra as well as the magnetization, resistance and magnetoresistance of the compounds SrFeO{sub 3-{delta}}, Sr{sub 3}Fe{sub 2}O{sub 7-{delta}} and CaFeO{sub 3} as a function of temperature. We describe the preparation of nearly stoichiometric SrFeO{sub 3-{delta}} crystals with {delta}<0.05. we have performed lattice dynamics calculations for the ideal composition SrFeO{sub 3.00} in order to assign the phonon modes observed in infra-red experiments. We have measured the Raman spectra of the tetragonal phase in the temperature range 13 K to 300 K and of the orthorhombic phase in the temperature range 6 K to 475 K. We have measured the temperature dependence of the magnetization for the magnetic field along high-symmetry axes of the crystal structure. We have also performed neutron diffraction measurements. The resistivity and the magnetoresistance were measured in the range 10 K to 300 K. Finally we have measured the Raman spectra of the same sample in the temperature range 15 K to 440 K. In order to assign the observed modes, we have performed lattice dynamics calculations based on the published crystal structure of Sr{sub 3}Fe{sub 2}O{sub 7}. (orig.)

A reexamination of cellulose carbon-bound hydrogen deltaD measurements and some factors affecting plant-water D/H relationships

International Nuclear Information System (INIS)

Yapp, C.J.; Epstein, S.

1982-01-01

The method of Epstein et al. (1976) for analysis of D/H ratios of cellulose carbon-bound hydrogen has been modified. This modified 'renitration' method yields deltaD values which are in agreement with those obtained by the sodium chlorite delignification method. Comparison of results obtained by the renitration method with the published results of Epstein et al. indicate some differences in the deltaD values of individual samples. However, the overall plant-water deltaD relationship determined by Epstein et al., is not greatly changed upon redetermination by the renitration method. Additional data from a variety of plants representing a wide geographical range reveal that relative humidity is an important variable in determining the deltaD value of cellulose C-H hydrogen on this inter-regional scale. The role of relative humidity can be reasonably explained by a leaf water model that assumes an isotopic steady-state during transpiration. These results reaffirm the conclusion of Epstein et al., that the deltaD variations of the source water are the dominant control of the deltaD variations of cellulose C-H hydrogen from naturally grown plants. Thus, there is an expectation that these cellulose deltaD variations can have climate significance. (author)

The influence of delta formation mechanism on geotechnical property sequence of the late Pleistocene–Holocene sediments in the Mekong River Delta

Directory of Open Access Journals (Sweden)

Truong Minh Hoang

2016-11-01

Full Text Available The aim of the study was to characterize a variety of microstructure development-levels and geotechnical property sequences of the late Pleistocene–Holocene deposits in the Mekong River delta (MRD, and the paper furthermore discusses the influences of delta formation mechanisms on them. The survey associated the geotechnical engineering and the sedimentary geology of the late Pleistocene–Holocene deposits at five sites and also undifferentiated Pleistocene sediments. A cross-section which was rebuilt in the delta progradation-direction and between the Mekong and Bassac rivers represents the stratigraphy. Each sedimentary unit was formed under a different delta formation mechanism and revealed a typical geotechnical property sequence. The mechanical behaviors of the sediment succession in the tide-dominated delta with significant fluvial-activity and material source tend to be more cohesionless soils and strengths than those in the tide- and wave-dominated delta and even the coast. The particular tendency of the mechanical behavior of the deposit succession can be reasonably estimated from the delta formation mechanism. The characteristics of the clay minerals from the Mekong River produced the argillaceous soil which does not have extremely high plasticity. The microstructure development-levels are low to very high indicating how to choose hydraulic conductivity value, k, for estimating overconsolidation ratio, OCR, by the piezocone penetration tests (CPTU. The OCR of sediments in the delta types strangely change with depth but none less than 1. The post-depositional processes significantly influenced the microstructure development, particularly the dehydrating and oxidizing processes.

Displacement waves in La/sub 2/CuO(4-delta) and La(1. 85)Sr(0. 15)CuO(4-delta)

Energy Technology Data Exchange (ETDEWEB)

Kajitani, T.; Onozuka, T.; Yamaguchi, Y.; Hirabayashi, M.; Syono, Y.

1987-11-01

Structural investigation of orthorhombic La/sub 2/CuO(4-delta) and La(1.85)Sr(0.15)CuO(4-delta) was carried out by means of X-ray and neutron diffraction on the basis of the space group Cmmm. The periodic expansion/contraction type distortion of CuO6 octahedra was found in both orthorhombic compounds. The distortion is nearly one-dimensional in La/sub 2/CuO(4-delta) but is two-dimensional in La(1.85)Sr(0.15)CuO(4-delta). The existence of a charge-density wave is highly possible in the structures. 20 references.

How yield relates to ash content, Delta 13C and Delta 18O in maize grown under different water regimes.

Science.gov (United States)

Cabrera-Bosquet, Llorenç; Sánchez, Ciro; Araus, José Luis

2009-11-01

Stable isotopes have proved a valuable phenotyping tool when breeding for yield potential and drought adaptation; however, the cost and technical skills involved in isotope analysis limit its large-scale application in breeding programmes. This is particularly so for Delta(18)O despite the potential relevance of this trait in C(4) crops. The accumulation of minerals (measured as ash content) has been proposed as an inexpensive way to evaluate drought adaptation and yield in C(3) cereals, but little is known of the usefulness of this measure in C(4) cereals such as maize (Zea mays). The present study investigates how yield relates to ash content, Delta(13)C and Delta(18)O, and evaluates the use of ash content as an alternative or complementary criterion to stable isotopes in assessing yield potential and drought resistance in maize. A set of tropical maize hybrids developed by CIMMYT were subjected to different water availabilities, in order to induce water stress during the reproductive stages under field conditions. Ash content and Delta(13)C were determined in leaves and kernels. In addition, Delta(18)O was measured in kernels. Water regime significantly affected yield, ash content and stable isotopes. The results revealed a close relationship between ash content in leaves and the traits informing about plant water status. Ash content in kernels appeared to reflect differences in sink-source balance. Genotypic variation in grain yield was mainly explained by the combination of ash content and Delta(18)O, whilst Delta(13)C did not explain a significant percentage of such variation. Ash content in leaves and kernels proved a useful alternative or complementary criterion to Delta(18)O in kernels for assessing yield performance in maize grown under drought conditions.

Hydrological and Climatic Significance of Martian Deltas

Science.gov (United States)

Di Achille, G.; Vaz, D. A.

2017-10-01

We a) review the geomorphology, sedimentology, and mineralogy of the martian deltas record and b) present the results of a quantitative study of the hydrology and sedimentology of martian deltas using modified version of terrestrial model Sedflux.

Delta Plaza kohvik = The Delta Plaza Café / Margit Mutso

Index Scriptorium Estoniae

Mutso, Margit, 1966-

2010-01-01

Tallinnas Pärnu mnt. 141 asuva kohviku Delta Plaza sisekujundusest. Sisearhitektid Tiiu Truus ja Marja Viltrop (Stuudio Truus OÜ). Hoone arhitektid Jüri Okas ja Marika Lõoke (AB J. Okas & M. Lõoke). Žürii liikme Mait Summataveti arvamus kohvikust

Studying medium effects with the optimized {delta} expansion

Energy Technology Data Exchange (ETDEWEB)

Krein, G [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil); Menezes, D P [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Fisica; Nielsen, M [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Pinto, M B [Montpellier-2 Univ., 34 (France). Lab. de Physique Mathematique

1995-04-01

The possibility of using the optimized {delta} expansion for studying medium effects on hadronic properties in quark or nuclear matter is investigated. The {delta} expansion is employed to study density effects with two commonly used models in hadron and nuclear physics, the Nambu-Jona-Lasinio model for the dynamical chiral symmetry breaking and the Walecka model for the equation of state of nuclear matter. The results obtained with the {delta} expansion are compared to those obtained with the traditional Hartree-Fock approximation. Perspectives for using the {delta} expansion in other field theoretic models in hadron and nuclear physics are discussed. (author). 17 refs, 9 figs.

Mode Coupling and Nonlinear Resonances of MEMS Arch Resonators for Bandpass Filters

KAUST Repository

Hajjaj, Amal Z.

2017-01-30

We experimentally demonstrate an exploitation of the nonlinear softening, hardening, and veering phenomena (near crossing), where the frequencies of two vibration modes get close to each other, to realize a bandpass filter of sharp roll off from the passband to the stopband. The concept is demonstrated based on an electrothermally tuned and electrostatically driven MEMS arch resonator operated in air. The in-plane resonator is fabricated from a silicon-on-insulator wafer with a deliberate curvature to form an arch shape. A DC current is applied through the resonator to induce heat and modulate its stiffness, and hence its resonance frequencies. We show that the first resonance frequency increases up to twice of the initial value while the third resonance frequency decreases until getting very close to the first resonance frequency. This leads to the phenomenon of veering, where both modes get coupled and exchange energy. We demonstrate that by driving both modes nonlinearly and electrostatically near the veering regime, such that the first and third modes exhibit softening and hardening behavior, respectively, sharp roll off from the passband to the stopband is achievable. We show a flat, wide, and tunable bandwidth and center frequency by controlling the electrothermal actuation voltage.

LIVER TRANSPLANTATION IN HEPATITIS DELTA: SOUTH AMERICA EXPERIENCE

Directory of Open Access Journals (Sweden)

Daniel Souza LIMA

Full Text Available ABSTRACT BACKGROUND: The Amazon region is one of the main endemic areas of hepatitis delta in the world and the only one related to the presence of genotype 3 of the delta virus. OBJECTIVE: To analyze the profile, mortality and survival of cirrhotic patients submitted to liver transplantation for chronic hepatitis delta virus and compare with those transplanted by hepatitis B virus monoinfection. METHODS: Retrospective, observational and descriptive study. From May 2002 to December 2011, 629 liver transplants were performed at the Walter Cantídio University Hospital, of which 29 patients were transplanted due to cirrhosis caused by chronic delta virus infection and 40 by hepatitis B chronic monoinfection. The variables analyzed were: age, sex, MELD score, Child-Pugh score, upper gastrointestinal bleeding and hepatocellular carcinoma occurrence before the transplantation, perioperative platelet count, mortality and survival. RESULTS: The Delta Group was younger and all came from the Brazilian Amazon Region. Group B presented a higher proportion of male patients (92.5% compared to Group D (58.6%. The occurrence of upper gastrointestinal bleeding before transplantation, MELD score, and Child-Pugh score did not show statistical differences between groups. The occurrence of hepatocellular carcinoma and mortality were higher in the hepatitis B Group. The survival in 4 years was 95% in the Delta Group and 75% in the B Group, with a statistically significant difference (P=0.034. Patients with hepatitis delta presented more evident thrombocytopenia in the pre-transplantation and in the immediate postoperative period. CONCLUSION: The hepatitis by delta virus patients who underwent liver transplantation were predominantly male, coming from the Brazilian Amazon region and with similar liver function to the hepatitis B virus patients. They had a lower incidence of hepatocellular carcinoma, more marked perioperative thrombocytopenia levels and frequent

Investigation of the variation of the specific heat capacity of local soil samples from the Niger delta, Nigeria with moisture content

International Nuclear Information System (INIS)

Ofoegbu, C.O.; Adjepong, S.K.

1987-11-01

Results of an investigation of the variation, with moisture content, of the specific heat capacity of samples of three texturally different types of soil (clayey, sandy and sandy loam) obtained from the Niger delta area of Nigeria, are presented. The results show that the specific heat capacities of the soils studied, increase with moisture content. This increase is found to be linear for the entire range of moisture contents considered (0-25%), in the case of the sandy loam soil while for the clayey and sandy soils the specific heat capacity is found to increase linearly with moisture content up to about 15% after which the increase becomes parabolic. The rate of increase of specific heat capacity with moisture content appears to be highest in the clayey soil and lowest in the sandy soil. It is thought that the differences in the rates of increase of specific heat capacity with moisture content, observed for the soils, reflect the soils' water-retention capacities. (author) 3 refs, 5 figs

Transcriptomic profiling of pancreatic alpha, beta and delta cell populations identifies delta cells as a principal target for ghrelin in mouse islets

DEFF Research Database (Denmark)

Adriaenssens, Alice E; Svendsen, Berit; Lam, Brian Y H

2016-01-01

cytometry and analysed by RNA sequencing. The role of the ghrelin receptor was validated by imaging delta cell calcium concentrations using islets with delta cell restricted expression of the calcium reporter GCaMP3, and in perfused mouse pancreases. RESULTS: A database was constructed of all genes...... expressed in alpha, beta and delta cells. The gene encoding the ghrelin receptor, Ghsr, was highlighted as being highly expressed and enriched in delta cells. Activation of the ghrelin receptor raised cytosolic calcium levels in primary pancreatic delta cells and enhanced somatostatin secretion in perfused...... pancreases, correlating with a decrease in insulin and glucagon release. The inhibition of insulin secretion by ghrelin was prevented by somatostatin receptor antagonism. CONCLUSIONS/INTERPRETATION: Our transcriptomic database of genes expressed in the principal islet cell populations will facilitate...

Doubly truncated FosB isoform (Delta2DeltaFosB) induces osteosclerosis in transgenic mice and modulates expression and phosphorylation of Smads in osteoblasts independent of intrinsic AP-1 activity

DEFF Research Database (Denmark)

Sabatakos, George; Rowe, Glenn C; Kveiborg, Marie

2008-01-01

DeltaFosB and a further truncated isoform (Delta2DeltaFosB) that lacks known transactivation domains but, like DeltaFosB, induces increased expression of osteoblast marker genes. MATERIALS AND METHODS: To test Delta2DeltaFosB's ability to induce bone formation in vivo, we generated transgenic mice......6 expression. CONCLUSIONS: DeltaFosB's AP-1 transactivating function is not needed to induce increased bone formation, and Delta2DeltaFosB may act, at least in part, by increasing Smad1 expression, phosphorylation, and translocation to the nucleus....

Soils, people and policy: land resource management conundrum in the Okavango Delta, Botswana

Directory of Open Access Journals (Sweden)

Oluwatoyin Dare Kolawole

2017-06-01

Full Text Available The multi-faceted aspects of natural resource governance underscore the complex nature of the subject. The intricacies associated with the skewed power relations between those who allocate these resources (land, in this case and those who access and use them vis à vis environmental conservation make the subject a daunting one. Based on preliminary field observations and farmers’ opinions on soil health conditions in the Okavango Delta, the paper assesses the nutrient status of selected farmers’ fields and how the smallholders and government respond to this peculiar ecological environment. It specifically analyses small farmers’ perceptions on the political ecology of soil management in the area. We used a multi-stage sampling procedure to sample 228 smallholder farmers. The smallholders were interviewed using interview schedules. Key informant interviews were used to collect qualitative data from farmers as well. Thirty-three (33 composite soil samples were collected from 30 farmers’ plots in three farming communities (Makalamabedi, Nokaneng and Mohembo. Laboratory analysis shows that most soils in the wetland and its dryland surroundings are generally acidic, low in essential nutients as well as in cation-exchange-capacity (CEC. However, the results of a one-way analysis of variance (ANOVA conducted shows significant differences in soil nutrient levels in different locations within the Delta. While farming remains an important livelihood of rural communities, policies on natural resource governance particularly along the river channels delimit local farmers’ ability to engage in meaningful soil fertility management. The low CEC of the soils is an indication that holistic cultural practices, which are beyond mere chemical fertilizations are critical and more desirable for improved soil health and sustainable rural livelihoods in the Delta.

Evidence of an Exponential Decay Pattern of the Hepatitis Delta Virus Evolution Rate and Fluctuations in Quasispecies Complexity in Long-Term Studies of Chronic Delta Infection.

Directory of Open Access Journals (Sweden)

Maria Homs

Full Text Available Chronic HDV infection can cause a severe form of viral hepatitis for which there is no specific treatment. Characterization of the hepatitis B or C viral quasispecies has provided insight into treatment failure and disease recurrence following liver transplantation, has proven useful to understand hepatitis B e antigen seroconversion, and has helped to predict whether hepatitis C infection will resolve or become chronic. It is likely that characterization of the hepatitis delta virus (HDV quasispecies will ultimately have similar value for the management of this infection. This study sought to determine the RNA evolution rates in serum of chronic hepatitis delta (CHD treatment-naïve patients, using next-generation sequencing methods. The region selected for study encompassed nucleotide positions 910 to 1270 of the genome and included the amber/W codon. Amber/W is a substrate of the editing process by the ADAR1 host enzyme and is essential for encoding the 2 delta antigens (HDAg. The amber codon encodes the small (unedited HDAg form and the W codon the large (edited HDAg form. The evolution rate was analyzed taking into account the time elapsed between samples, the percentage of unedited and edited genomes, and the complexity of the viral population. The longitudinal studies included 29 sequential samples from CHD patients followed up for a mean of 11.5 years. In total, 121,116 sequences were analyzed. The HDV evolution rate ranged from 9.5x10-3 to 1.2x10-3 substitutions/site/year and showed a negative correlation with the time elapsed between samples (p<0.05. An accumulation of transition-type changes was found to be responsible for higher evolution rates. The percentages of unedited and edited genomes and the quasispecies complexity showed no relationships with the evolution rate, but the fluctuations in the percentages of genomes and in complexity suggest continuous adaptation of HDV to the host conditions.

Delta Cafés (Portugal: Sustainable Business Development

Directory of Open Access Journals (Sweden)

Olgierd Swiatkiewicz

2017-12-01

Full Text Available In the case study of Delta Cafés we discuss the sustainable development of the Portuguese company and brand over the 55 years of their existence. Delta Cafés has already been analyzed in terms of marketing activity, social responsibility, management control systems, etc. In this paper, we refer to these studies, and we reach the sources, i.e. the information provided by the Delta Cafés itself. Due to the nature of the coffee market and the use of case study methodology, we start the presentation of this case from a broader context, describing the coffee market in the world and characterizing the coffee market in Portugal as well. Then we present the history of the development of the company and the brand Delta Cafés. The paper ends with concluding remarks in which we discuss the issues of social and environmental responsibility in the light of the development of Delta Cafés business and brand strategies. 

Measurement of delta-rays in ATLAS silicon sensors

CERN Document Server

The ATLAS collaboration

2013-01-01

In the inner detector of the ATLAS experiment at the LHC, $\\delta$-rays originating from particle interactions in the silicon sensors may cause additional hit channels. A method for identifying silicon hit clusters that are enlarged due to the emission of a $\\delta$-ray is presented. Using pp collision data the expectation is confirmed that the $\\delta$-ray production rate depends linearly on the path length of the particle in silicon, independently of layer radius and detector technology. The range of the $\\delta$-rays, which is a property of the material and should not depend on anything else, is indeed found to be constant as a function of detector layer, path length in silicon and momentum of the particle traversing the silicon. As a by-product of this analysis a method is proposed that could correct for the effect of these $\\delta$-rays, and this could be used to improve track reconstruction.

Benthic sediment data from eleven stations in the Mobile-Tensaw River Delta, Alabama on 17 June 1981 (NODC Accession 0118497)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Benthic sediment samples were collected from eleven stations in the Mobile-Tensaw River Delta on 17 June 1981. Samples were analyzed for particle size distribution...

Studies of Louisiana's Deltas and Wetlands using SAR

Science.gov (United States)

Jones, C. E.

2017-12-01

Sustainable coastal environments exist in delicate balance between subsidence, erosion, and sea level rise on one hand and accretion of sediment and retention of decomposing organic matter on the other. In this talk we present results from a series of studies using an airborne L-band SAR (UAVSAR) to measure changing conditions in the Mississippi River Delta and coastal wetlands of Louisiana. Change within the Mississippi River delta (MRD), which is a highly engineered environment, is contrasted to those in the Wax Lake Delta, a small, naturally evolving delta located to the west of the current-day lobe of the MRD. The UAVSAR studies provide evidence that in the MRD subsidence and erosion related to human activities are increasing risk of flooding, submergence, and land loss. These are not seen in the Wax Lake Delta, where new land is forming. We evaluate geomorphic and hydrologic changes In the Wax Lake Delta and wetlands hydrologically connected to the Wax Lake Outlet canal that are apparent on the timescales of the UAVSAR data set, which consists of both near-yearly acquisitions (2009-2016) and several series of repeat acquisitions in 2015 and 2016 capturing conditions across a tidal cycle. Using the yearly data, we observe the evolution of subaqueous channels and crevasses in the delta and changes in distributary channels within the wetlands. We use water level change derived from InSAR applied to the rapid repeat data acquired during different stages of a tidal cycle to study the natural pattern of water flux within the delta and the coastal wetlands. The studies, results, and plans for future work will be presented. This work was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under contracts with the California Dept. of Water Resources and with the National Aeronautics and Space Administration.

Study of the characteristics of forced homogeneous turbulence using band-pass Fourier filtering

Energy Technology Data Exchange (ETDEWEB)

Kareem, Waleed Abdel [Suez Canal University, Suez (Egypt)

2012-03-15

Simulations of forced homogeneous isotropic turbulence with resolutions of 128{sup 3} and 256{sup 3} using the Lattice Boltzmann method are carried out. The multi-scale vortical structures are identified using the band-pass Fourier cutoff filtering. Three fields at each simulation are extracted and their characteristics are studied. The vortical structures are visualized using the Q-identification method. A new lattice segmentation scheme to identify the central axes of the vortical structures is introduced. The central points of each vortex are identified and they are connected using the direction cosines technique. Results show that the Q-spectrum of the fine scale field survives at low and high wave-numbers. However, the large and intermediate Q-spectra survives till wave-numbers less than or equal to twice the used velocity cutoff wave-numbers. It is found that the extracted central axes clearly resemble the corresponding vortical structures at each scale. Using the central axes scheme, the radii and lengths of the vortical structures at each scale are determined and compared. It is also found that the radii of the identified vortical structures at each scale in both simulations are of the order of several times the Kolmogorov microscales.

Can Computational Sediment Transport Models Reproduce the Observed Variability of Channel Networks in Modern Deltas?

Science.gov (United States)

Nesvold, E.; Mukerji, T.

2017-12-01

River deltas display complex channel networks that can be characterized through the framework of graph theory, as shown by Tejedor et al. (2015). Deltaic patterns may also be useful in a Bayesian approach to uncertainty quantification of the subsurface, but this requires a prior distribution of the networks of ancient deltas. By considering subaerial deltas, one can at least obtain a snapshot in time of the channel network spectrum across deltas. In this study, the directed graph structure is semi-automatically extracted from satellite imagery using techniques from statistical processing and machine learning. Once the network is labeled with vertices and edges, spatial trends and width and sinuosity distributions can also be found easily. Since imagery is inherently 2D, computational sediment transport models can serve as a link between 2D network structure and 3D depositional elements; the numerous empirical rules and parameters built into such models makes it necessary to validate the output with field data. For this purpose we have used a set of 110 modern deltas, with average water discharge ranging from 10 - 200,000 m3/s, as a benchmark for natural variability. Both graph theoretic and more general distributions are established. A key question is whether it is possible to reproduce this deltaic network spectrum with computational models. Delft3D was used to solve the shallow water equations coupled with sediment transport. The experimental setup was relatively simple; incoming channelized flow onto a tilted plane, with varying wave and tidal energy, sediment types and grain size distributions, river discharge and a few other input parameters. Each realization was run until a delta had fully developed: between 50 and 500 years (with a morphology acceleration factor). It is shown that input parameters should not be sampled independently from the natural ranges, since this may result in deltaic output that falls well outside the natural spectrum. Since we are

Compact HTS bandpass filter employing CPW quarter-wavelength resonators with strongly-coupled open stubs

Energy Technology Data Exchange (ETDEWEB)

Satoh, K; Koizumi, D; Narahashi, S [Research Laboratories, NTT DoCoMo, Inc., 3-5 Hikari-no-oka, Yokosuka, Kanagwa, 239-8536 (Japan)], E-mail: satokei@nttdocomo.co.jp

2008-02-01

This paper presents a novel compact high temperature superconducting (HTS) bandpass filter (BPF) that employs a newly developed miniaturized coplanar-waveguide (CPW) quarter-wavelength resonators with strongly-coupled open stubs. The proposed resonator has a structure in which the open stubs are aligned close to the center conductor of the resonator. This is because strongly-coupled resonators have widely-split resonant frequencies, and the lowest resonant frequency is employed as the fundamental resonant frequency of the resonator in order to achieve miniaturization. The proposed resonator is 1.7 mm or less in length for use in the 5-GHz band, whereas the conventional straight resonator is approximately 6.4 mm long. A four-pole Chebyshev HTS BPF is designed and fabricated using the proposed CPW resonators. The entire length of the proposed four-pole filter is 15 mm. The frequency response of the fabricated filter agrees well with the electromagnetic simulation results. The proposed filter achieves a size reduction of at least 50% compared to previously reported filters without any degradation in the frequency characteristics.

Floating City IJmeer : Accelerator for Delta Technology

NARCIS (Netherlands)

De Graaf, R.; Fremouw, M.; Van Bueren, B.; Czapiewska, K.; Kuijper, M.

2006-01-01

Climate change, sea level rise, population growth and ongoing urbanization result in higher vulnerability of the Rhine delta because it will result in increased flooding frequency, increasing investments and increased use of water, energy and other resources. The Rhine Delta also faces strong

[Simultaneous determination of delta13C values of glycerol and ethanol in wine by liquid chromatography coupled with isotope ratio mass spectrometry].

Science.gov (United States)

Li, Xuemin; Jia, Guangqun; Cao, Yanzhong; Zhang, Jinjie; Wang, Lei; Sun, Huiyuan

2013-12-01

A novel procedure was established for the characterization of delta13C values of glycerol and ethanol in wine by liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). Several parameters influencing the separation of glycerol and ethanol from wine matrix were optimized. The precision and accuracy of the proposed method were 0.15 per thousand to 0.26 per thousand and 0.11 per thousand to 0.28 per thousand, respectively. The results obtained for 40 wine samples displayed that the delta13C value of glycerol ranged from--26.87 per thousand to--32.96 per thousand and that of ethanol ranged from--24.06 per thousand to--28.29 per thousand. Close correlations (R = 0.82) were obtained between the delta13C values of glycerol and ethanol. The proposed method didn't need complex sample treatment, and the delta13C values of glycerol and ethanol in wine can be simultaneously determined, thus improving the method in terms of simplicity and speed compared with traditional methods.

Is there a self-organization principle of river deltas?

Science.gov (United States)

Tejedor, Alejandro; Longjas, Anthony; Foufoula-Georgiou, Efi

2017-04-01

River deltas are known to possess a complex topological and flux-partitioning structure which has recently been quantified using spectral graph theory [Tejedor et al., 2015a,b]. By analysis of real and simulated deltas it has also been shown that there is promise in formalizing relationships between this topo-dynamic delta structure and the underlying delta forming processes [e.g., Tejedor et al., 2016]. The question we pose here is whether there exists a first order organizational principle behind the self-organization of river deltas and whether this principle can be unraveled from the co-evolving topo-dynamic structure encoded in the delta planform. To answer this question, we introduce a new metric, the nonlocal Entropy Rate (nER) that captures the information content of a delta network in terms of the degree of uncertainty in delivering fluxes from any point of the network to the shoreline. We hypothesize that if the "guiding principle" of undisturbed deltas is to efficiently and robustly build land by increasing the diversity of their flux pathways over the delta plane, then they would exhibit maximum nonlocal Entropy Rate at states at which geometry and flux dynamics are at equilibrium. At the same time, their nER would be non-optimal at transient states, such as before and after major avulsions during which topology and dynamics adjust to each other to reach a new equilibrium state. We will present our results for field and simulated deltas, which confirm this hypothesis and open up new ways of thinking about self-organization, complexity and robustness in river deltas. One particular connection of interest might have important implications since entropy rate and resilience are related by the fluctuation theorem [Demetrius and Manke, 2005], and therefore our results suggest that deltas might in fact self-organize to maximize their resilience to structural and dynamic perturbations. References: Tejedor, A., A. Longjas, I. Zaliapin, and E. Foufoula

A Regional Survey of River-plume Sedimentation on the Mississippi River Delta Front

Science.gov (United States)

Courtois, A. J.; Bentley, S. J.; Xu, K.; Georgiou, I. Y.; Maloney, J. M.; Miner, M. D.; Chaytor, J. D.; Smith, J.

2017-12-01

Many studies of the Mississippi River and Delta (MRD) have shown historic declines in sediment load reaching the main river distributaries over the last few decades. Recent studies also reported that 50% of the suspended load during floods is sequestered within the delta. While the impact of declining sediment load on wetland loss is well documented, submarine sedimentary processes on the delta front during this recent period of declining sediment load are understudied. To better understand modern sediment dispersal and deposition across the Mississippi River Delta Front, 31 multicores were collected in June 2017 from locations extending offshore from Southwest Pass, South Pass, and Pass a Loutre (the main river outlets) in water depths of 25-280 m. Core locations were selected based on multibeam bathymetry and morphology collected by the USGS in May 2017; the timing of collection coincided with the end of annual peak discharge on the Mississippi River. This multi-agency survey is the first to study delta-front sedimentary processes regionally with such a wide suite of tools. Target locations for coring included the dominant depositional environments: mudflow lobes, gullies, and undisturbed prodelta. Cores were subsampled at 2 cm intervals and analyzed for Beryllium-7 activity via gamma spectrometry; in such settings, Be-7 can be used as a tracer of sediment recently delivered from fluvial origin. Results indicate a general trend of declining Be-7 activity with increasing distance from source, and in deeper water. Inshore samples near Southwest Pass show the deepest penetration depth of Be-7 into the sediment (24-26 cm), which is a preliminary indicator of rapid seasonal sedimentation. Nearshore samples from South Pass exhibited similar Be-7 penetration depths, with results near Pass a Loutre to 14-16 cm depth. Be-7 remains detectable to 2 cm in water 206 m deep, approximately 20 km from South Pass. Sediment dispersal remains impressive offshore from all three

Assessment and potential sources of metals in the surface sediments of the Yellow River Delta, Eastern China.

Science.gov (United States)

Cheng, Qingli; Lou, Guangyan; Huang, Wenhai; Li, Xudong

2017-07-01

The Yellow River Delta is the most intact estuary wetland in China and suffers from great pressure of metals. Seventy-seven surface sediment samples were collected in the delta, and contents of Cu, Pb, Cd, Cr, Zn, Ni, and Mn were analyzed by inductively coupled plasma spectrometry and those of Hg and As by atomic fluorescence spectrometry. The results showed that means of metal contents (ppm, dry weight) were as follows: Hg, 0.04; Cr, 61.72; Cu, 20.97; Zn, 60.73; As, 9.47; Pb, 21.91; Cd, 0.12; Ni, 27.24; and Mn, 540.48. 43.8% of Hg and 14.3% of Cd were from the allogenic source while others from the authigenic source. The results of the geoaccumulation indexes appeared that 6.5% of sites from the estuarine and the Gudao areas were moderately polluted by Hg. All ecological risk index values of Hg and 37.7% of Cd were more than 40, which were the main factors of strongly and moderately potential ecological risks of 37.7% of sites in the delta. High Cd contents may be due to the alkaline conditions of the delta and the unreasonable management of the farmland, while the abnormal distribution of Hg to the wet or dry deposition and the erosion of the seawater. It was suggested to monitor Hg content in the atmosphere of the Yellow River Delta. The results were expected to update the pollution status of metals in the delta and created awareness of preserving the sound condition of the Yellow River Delta.

Electronic Structure of TlBa2CaCu2O(7-Delta)

Science.gov (United States)

Vasquez, R. P.; Novikov, D. L.; Freeman, A. J.; Siegal, M. P.

1997-01-01

The core levels of TlBa2CaCu2O(7-delta) (Tl-1212) epitaxial films have been measured with X-ray photoelectron spectroscopy (XPS). The valence electronic structure has been determined using the full-potential linear muffin-tin-orbital band-structure method and measured with XPS. The calculations show that a van Hove singularity (VHS) lies above the Fermi level (E(sub F)) for the stoichiometric compound (delta = 0.5), while for 50% oxygen vacancies in the Tl-O layer (delta = 0.5) E(sub F) is in close proximity to the VHS. Samples annealed in nitrogen (to reduce the hole overdoping by the removal of oxygen) exhibit higher core-level binding energies and a higher T(sub c), consistent with a shift of E(sub F) closer to the VHS. Comparisons are made to the core levels and valence bands of Tl2Ba2CaCu2O(8 + delta)(Tl-2212) and HgBa2CaCu2O)6 + delta) (Hg- 1212). The similarity of the Cu 2p(sub 3/2) spectra for Tl-1212 and Tl-2212 indicates that the number of Tl-O layers has little effect on the Cu-O bonding. However, the Tl-1212 and Hg-1212 Cu 2p(sub 3/2) signals exhibit differences which suggest that the replacement of T(sup 3+) with Hg(sup 2+) results in a decrease in the O 2p right arrow Cu 3d charge-transfer energy and differences in the probabilities of planar vs apical oxygen charge transfer and/or Zhang-Rice singlet-state formation. Differences between the Tl-1212 and the Tl-2212 and Hg-1212 measured valence bands are consistent with the calculated Cu 3d and (Tl,Hg) 6s/5d partial densities of states.

Open source integrated modeling environment Delta Shell

Science.gov (United States)

Donchyts, G.; Baart, F.; Jagers, B.; van Putten, H.

2012-04-01

In the last decade, integrated modelling has become a very popular topic in environmental modelling since it helps solving problems, which is difficult to model using a single model. However, managing complexity of integrated models and minimizing time required for their setup remains a challenging task. The integrated modelling environment Delta Shell simplifies this task. The software components of Delta Shell are easy to reuse separately from each other as well as a part of integrated environment that can run in a command-line or a graphical user interface mode. The most components of the Delta Shell are developed using C# programming language and include libraries used to define, save and visualize various scientific data structures as well as coupled model configurations. Here we present two examples showing how Delta Shell simplifies process of setting up integrated models from the end user and developer perspectives. The first example shows coupling of a rainfall-runoff, a river flow and a run-time control models. The second example shows how coastal morphological database integrates with the coastal morphological model (XBeach) and a custom nourishment designer. Delta Shell is also available as open-source software released under LGPL license and accessible via http://oss.deltares.nl.

How Rapid Change Affects Deltas in the Arctic Region

Science.gov (United States)

Overeem, I.; Bendixen, M.

2017-12-01

Deltas form where the river drains into the ocean. Consequently, delta depositional processes are impacted by either changes in the respective river drainage basin or by changes in the regional marine environment. In a warming Arctic region rapid change has occurred over the last few decades in both the terrestrial domain as well as in the marine domain. Important terrestrial controls include 1) change in permafrost possibly destabilizing river banks, 2) strong seasonality of river discharge due to a short melting season, 3) high sediment supply if basins are extensively glaciated, 4) lake outbursts and ice jams favoring river flooding. Whereas in the Arctic marine domain sea ice loss promotes wave and storm surge impact, and increased longshore transport. We here ask which of these factors dominate any morphological change in Arctic deltas. First, we analyze hydrological data to assess change in Arctic-wide river discharge characteristics and timing, and sea ice concentration data to map changes in sea ice regime. Based on this observational analysis we set up a number of scenarios of change. We then model hypothetical small-scale delta formation considering change in these primary controls by setting up a numerical delta model, and combining it dynamically with a permafrost model. We find that for typical Greenlandic deltas changes in river forcing due to ice sheet melt dominate the morphological change, which is corroborated by mapping of delta progradation from aerial photos and satellite imagery. Whereas in other areas, along the North Slope and the Canadian Arctic small deltas are more stable or experienced retreat. Our preliminary coupled model allows us to further disentangle the impact of major forcing factors on delta evolution in high-latitude systems.

Sympathoadrenal, cardiovascular and blood gas responses to highly selective mu and delta opioid peptides.

Science.gov (United States)

Kiritsy-Roy, J A; Marson, L; Van Loon, G R

1989-12-01

The relative importance of mu and delta opioid receptors in brain regulation of sympathoadrenal, cardiovascular and respiratory function was investigated using highly selective mu and delta opioid peptide analogs. Groups of conscious rats received i.c.v. injections of either the mu-selective agonist, [D-Ala2, MePhe4, Gly-ol5]enkephalin (DAMGO) or the delta-selective agonist, [D-Pen2, D-Pen5]enkephalin (DPDPE). Blood pressure and heart rate were recorded continuously via a chronic catheter in the carotid artery, and arterial blood samples were taken at intervals through the same catheter for determination of blood pH, pCO2, pO2 and plasma catecholamine concentrations. Both DAMGO and DPDPE increased plasma catecholamine levels and blood pressure in a dose-related manner. The slopes of the dose-response lines were parallel, but the delta compound was about 250 times less potent than DAMGO. Only the highest dose of 5 nmol of DAMGO caused a significant bradycardia, mediated by parasympathetic (vagal) activation. DAMGO and DPDPE also induced dose-dependent acidosis, with DAMGO again being much more potent than DPDPE. The effects of both DAMGO and DPDPE on plasma catecholamines, blood pressure and blood gases were antagonized by a mu-selective dose of naloxone (0.4 mg/kg i.a.). Intracerebroventricular administration of the delta-selective antagonist, ICI 174,864, only partially attenuated sympathoadrenal and blood gas responses to DAMGO or DPDPE. The pressor responses to DAMGO or DPDPE were resistant to antagonism by ICI 174,864. These results indicate that brain opioid receptors regulating autonomic outflow, cardiovascular and respiratory function are mainly of the mu type, although a delta opioid system may contribute to sympathoadrenal and respiratory effects of opioids.

The State of Bay–Delta Science 2016: An Introduction

Directory of Open Access Journals (Sweden)

Michael Healey

2016-07-01

Full Text Available doi: http://dx.doi.org/10.15447/sfews.2016v14iss2art5The State of Bay–Delta Science 2016 (SBDS is a collection of papers that summarizes the scientific understanding of the Sacramento–San Joaquin Delta, emphasizing progress made during the past decade.It builds on the first SBDS edition (Healey et al. 2008. Paper topics for this edition address the most relevant scientific issues in the Delta identified by senior scientists and managers. The topical papers cover issues ranging from contaminants in the Delta to levee stability, and from Delta food webs to recent discoveries about salmon migration. These papers are written for a scientific audience. Two additional papers, one describing the challenges of managing water and ecosystems in the Delta and another that discusses policy implications of the recent scientific findings, are written for a general audience. The papers will be published in at least two issues of San Francisco Estuary and Watershed Science and will be available as a set electronically.

Subcatchment deltas and upland features influence multiscale aquatic ecosystem recovery in damaged landscapes.

Science.gov (United States)

Kielstra, Brian W; Arnott, Shelley E; Gunn, John M

2017-12-01

Assessing biological recovery in damaged aquatic environments requires the consideration of multiple spatial and temporal scales. Past research has focused on assessing lake recovery from atmospheric or catchment disturbance at regional or catchment levels. Studies have also rarely considered the influences of adjacent terrestrial characteristics on within-lake habitats, such as subcatchment delta confluences. We used Hyalella azteca, a ubiquitous freshwater amphipod, as a sensitive indicator to assess the importance of local subcatchment scale factors in the context of multiscale lake recovery within the metal mining region of Sudbury, Canada following a period of major reductions in atmospheric pollution. At the regional scale, data from repeated surveys of 40 lakes showed higher probabilities of H. azteca occurrence with higher lake water conductivity, alkalinity, and pH and lower metal concentrations. The importance of metals decreased through time and the importance of higher conductivity, alkalinity, and pH increased. At the subcatchment scale, a subset of six lakes sampled across a colonization gradient revealed higher H. azteca abundances at subcatchment delta sites than non-delta sites in early colonization stages, and that abundance at delta sites was correlated with both within-lake habitat and terrestrial subcatchment characteristics. For example, wetland cover reduced the strength of positive associations between H. azteca abundance and macrophyte density. A single lake from this subset also revealed higher abundances at delta sites associated with higher concentrations of terrestrial organic matter and larger subcatchments. Our results demonstrate that factors affecting recovery can change with the scale of study, and that managing terrestrial-aquatic linkages is important for facilitating recovery processes within damaged lake ecosystems. © 2017 by the Ecological Society of America.

The low-temperature structures of Hgsub(3-delta)SbF6 and Hgsub(3-delta)TaF6

International Nuclear Information System (INIS)

Tun, Z.; Brown, I.D.

1986-01-01

The Hg chains in both Hgsub(3-delta)SbF 6 and Hgsub(3-delta)TaF 6 order below room temperature. Down to about 190 K the ordering results from the interaction between parallel chains. It is short range and is different for the two compounds. Below 190 K both compounds transform to an isostructural long-range-ordered phase which is driven by the interaction between perpendicular chains. The structure of this phase in both compounds has been determined. Hgsub(3-delta)SbF 6 at 173 K, delta=0.134(1), Msub(r)=810.6(2). It is monoclinic but pseudotetragonal with I4 1 /amd, a=7.655(1), c=12.558(1) A, V=735.9(2) A 3 , Z=4, Dsub(x)=7.314(3) Mg m -3 , graphite-monochromated Mo Kα radiation, lambda=0.71069 A, μ=64.8 mm -1 , F(000)=1337.1(3). Hgsub(3-delta)TaF 6 at 150 K is isostructural but has delta=0.142(1), Msub(r)=868.2(2), a=7.634(1), c=12.610(2) A, V=734.9(2) A, Dsub(x)=7.844(3) Mg m -3 , μ=76.4 mm -1 , F(000)=1422.6(3). Comparison of the low-temperature structures with those at room temperature shows that the thermal contraction results from the shortening of interatomic distances associated with the weak bonds, with the result that the MF 6 (M=Sb, Ta) host lattice shrinks more than the Hg chains. Variation of the atomic displacement parameters with temperature indicates that the large librational displacements of the MF 6 ion result from thermal motion rather than static disorder. (orig.)

Super-delta: a new differential gene expression analysis procedure with robust data normalization.

Science.gov (United States)

Liu, Yuhang; Zhang, Jinfeng; Qiu, Xing

2017-12-21

Normalization is an important data preparation step in gene expression analyses, designed to remove various systematic noise. Sample variance is greatly reduced after normalization, hence the power of subsequent statistical analyses is likely to increase. On the other hand, variance reduction is made possible by borrowing information across all genes, including differentially expressed genes (DEGs) and outliers, which will inevitably introduce some bias. This bias typically inflates type I error; and can reduce statistical power in certain situations. In this study we propose a new differential expression analysis pipeline, dubbed as super-delta, that consists of a multivariate extension of the global normalization and a modified t-test. A robust procedure is designed to minimize the bias introduced by DEGs in the normalization step. The modified t-test is derived based on asymptotic theory for hypothesis testing that suitably pairs with the proposed robust normalization. We first compared super-delta with four commonly used normalization methods: global, median-IQR, quantile, and cyclic loess normalization in simulation studies. Super-delta was shown to have better statistical power with tighter control of type I error rate than its competitors. In many cases, the performance of super-delta is close to that of an oracle test in which datasets without technical noise were used. We then applied all methods to a collection of gene expression datasets on breast cancer patients who received neoadjuvant chemotherapy. While there is a substantial overlap of the DEGs identified by all of them, super-delta were able to identify comparatively more DEGs than its competitors. Downstream gene set enrichment analysis confirmed that all these methods selected largely consistent pathways. Detailed investigations on the relatively small differences showed that pathways identified by super-delta have better connections to breast cancer than other methods. As a new pipeline, super-delta

Experimental river delta size set by multiple floods and backwater hydrodynamics.

Science.gov (United States)

Ganti, Vamsi; Chadwick, Austin J; Hassenruck-Gudipati, Hima J; Fuller, Brian M; Lamb, Michael P

2016-05-01

River deltas worldwide are currently under threat of drowning and destruction by sea-level rise, subsidence, and oceanic storms, highlighting the need to quantify their growth processes. Deltas are built through construction of sediment lobes, and emerging theories suggest that the size of delta lobes scales with backwater hydrodynamics, but these ideas are difficult to test on natural deltas that evolve slowly. We show results of the first laboratory delta built through successive deposition of lobes that maintain a constant size. We show that the characteristic size of delta lobes emerges because of a preferential avulsion node-the location where the river course periodically and abruptly shifts-that remains fixed spatially relative to the prograding shoreline. The preferential avulsion node in our experiments is a consequence of multiple river floods and Froude-subcritical flows that produce persistent nonuniform flows and a peak in net channel deposition within the backwater zone of the coastal river. In contrast, experimental deltas without multiple floods produce flows with uniform velocities and delta lobes that lack a characteristic size. Results have broad applications to sustainable management of deltas and for decoding their stratigraphic record on Earth and Mars.

A Modal Logic for Abstract Delta Modeling

NARCIS (Netherlands)

F.S. de Boer (Frank); M. Helvensteijn (Michiel); J. Winter (Joost)

2012-01-01

htmlabstractAbstract Delta Modeling is a technique for implementing (software) product lines. Deltas are put in a partial order which restricts their application and are then sequentially applied to a core product in order to form specific products in the product line. In this paper we explore the

Fast delta Hadamard transform

International Nuclear Information System (INIS)

Fenimore, E.E.; Weston, G.S.

1981-01-01

In many fields (e.g., spectroscopy, imaging spectroscopy, photoacoustic imaging, coded aperture imaging) binary bit patterns known as m sequences are used to encode (by multiplexing) a series of measurements in order to obtain a larger throughput. The observed measurements must be decoded to obtain the desired spectrum (or image in the case of coded aperture imaging). Decoding in the past has used a technique called the fast Hadamard transform (FHT) whose chief advantage is that it can reduce the computational effort from N 2 multiplies of N log 2 N additions or subtractions. However, the FHT has the disadvantage that it does not readily allow one to sample more finely than the number of bits used in the m sequence. This can limit the obtainable resolution and cause confusion near the sample boundaries (phasing errors). Both 1-D and 2-D methods (called fast delta Hadamard transforms, FDHT) have been developed which overcome both of the above limitations. Applications of the FDHT are discussed in the context of Hadamard spectroscopy and coded aperture imaging with uniformly redundant arrays. Special emphasis has been placed on how the FDHT can unite techniques used by both of these fields into the same mathematical basis

Four new Delta Scuti stars

Science.gov (United States)

Schutt, R. L.

1991-01-01

Four new Delta Scuti stars are reported. Power, modified into amplitude, spectra, and light curves are used to determine periodicities. A complete frequency analysis is not performed due to the lack of a sufficient time base in the data. These new variables help verify the many predictions that Delta Scuti stars probably exist in prolific numbers as small amplitude variables. Two of these stars, HR 4344 and HD 107513, are possibly Am stars. If so, they are among the minority of variable stars which are also Am stars.

Delta Evolution at Røde Elv, Disko Island, Greenland

Science.gov (United States)

Kroon, A.; Arngrimson, J.; Bendixen, M.; Sigsgaard, C.

2017-12-01

Ice, snow and freezing temperatures have a large impact on coastal morphodynamics in Arctic polar environments. A recent warming of the Arctic climate induces many changes along the arctic shorelines. Sea-levels are rising due to thermal expansion and due to an increased fresh water flux from the glaciers and land ice masses. At the same time, the ice coverage of the coastal waters reduces and the open water periods in summer extend. There is a strong seasonal variation with open waters and active rivers in summer and ice-covered coastal waters and inactive rivers in winter. Coastal processes by waves and tides are thus limited to the summer and early fall. Besides, there is also a strong daily variation in fluvial discharges due to the daily variations in glacier melt with maximum melt in the afternoon and minimum values at night. At the same time, the actual flux of the river to the coastal bay is influenced by the tidal phase. Low tides will enhance the transport to the delta front, while high tides will create stagnant waters over the delta plain. The delta of the Røde Elv is located in southwestern Disko Island in west Greenland. It has a relatively small (ca. 101 km2) and partly glaciated drainage basin (ca. 20%) and its sediments consist of a mixture of basaltic sands and gravels. The Røde Elv delta is located at the end of a pro-glacial and fluvial valley at about 20 km from the glacier. The shores of the delta are reworked by waves, predominantly from southwestern, southern (largest fetch, over 50 km), and southeastern directions. The environment has a micro- to meso- tidal range with a spring tidal range of 2.7 m. The morphologic changes on the delta over the last decades clearly showed a seaward extension of the delta and a periodic shift in the location of the main delta channel. In this presentation, we focus on quantification of water discharges and suspended sediment fluxes to the Røde Elv delta in western Greenland, and on the morphological

Implications for future survival of delta smelt from four climate change scenarios for the Sacramento–San Joaquin Delta, California

Science.gov (United States)

Brown, Larry R.; Bennett, William A.; Wagner, R. Wayne; Morgan-King, Tara; Knowles, Noah; Feyrer, Frederick; Schoellhamer, David H.; Stacey, Mark T.; Dettinger, Mike

2013-01-01

Changes in the position of the low salinity zone, a habitat suitability index, turbidity, and water temperature modeled from four 100-year scenarios of climate change were evaluated for possible effects on delta smelt Hypomesus transpacificus, which is endemic to the Sacramento–San Joaquin Delta. The persistence of delta smelt in much of its current habitat into the next century appears uncertain. By mid-century, the position of the low salinity zone in the fall and the habitat suitability index converged on values only observed during the worst droughts of the baseline period (1969–2000). Projected higher water temperatures would render waters historically inhabited by delta smelt near the confluence of the Sacramento and San Joaquin rivers largely uninhabitable. However, the scenarios of climate change are based on assumptions that require caution in the interpretation of the results. Projections like these provide managers with a useful tool for anticipating long-term challenges to managing fish populations and possibly adapting water management to ameliorate those challenges.

Morphodynamics of a cyclic prograding delta: the Red River, Vietnam

NARCIS (Netherlands)

Maren, D.S. van

2004-01-01

River deltas are inhabited by over 60% of the world population, and are, consequently, of paramount agricultural and economical importance. They constitute unique wetland envi ronments which gives river deltas ecological importance as well. Additionally, many deltas contain large accumulations of

Changes to subaqueous delta bathymetry following a high river flow event, Wax Lake Delta, LA, USA

Science.gov (United States)

Whaling, A. R.; Shaw, J.

2017-12-01

Sediment transport capacity is increased during high river flow (flood) events which are characterized by discharges that exceed the 15 year median daily statistic. The Wax Lake Delta (WLD) in coastal Louisiana has experienced 19 of these high flow events in the past 20 years, yet the depositional patterns of single floods are rarely measured in a field-scale deltaic setting. We characterize flood deposition and erosion patterns on the subaqueous portion of the WLD by differencing two Digital Elevation Models (DEMs) constructed from bathymetric surveys before and after the third largest flood in the WLD's recorded history. The total suspended sediment discharge for the 496 day inter-survey period was 2.14x107 cubic meters measured 21 km upstream of the delta apex. The difference map showed 1.06x107 cubic meters of sediment was deposited and 8.2x106 cubic meters was eroded, yielding 2.40x106 cubic meters of net deposition in the survey area ( 79.7 km2 ). Therefore the average deposition rate was 0.061 mm/day. Channel planform remained relatively unchanged for five out of six distributary passes however Gadwall Pass experienced a maximum channel displacement of 166 m ( 1 channel width) measured from the thalweg centerline. Channel tip extension was negligible. In addition, channel displacement was not concentrated at any portion along the channel centerline. Maximum erosion occurred within channel margins and increased upstream whereas maximum deposition occurred immediately outside the channel margins. Sediment eroded from the survey area was either subsequently re-deposited or transported out of the system. Our results show that up to 77.4% of deposition in the survey area originated from sediment eroded during the flood. Surprisingly, only 11.2% of the total suspended sediment discharge was retained in the subaqueous portion of the delta after the flood. We conclude that a high flow event does not produce channel progradation. Rather, high flow causes delta

Isotopic composition of steam samples from Lanzarote, Canary Islands

Energy Technology Data Exchange (ETDEWEB)

Arana, V. (CSIC, Madrid); Panichi, C.

1974-12-01

The isotopic analysis of the steam samples collected in the geothermal area of Lanzarote show that the values of delta D are practically constant, and those of delta /sup 18/O range in a shift of 17 /sup 0///sub 00/ reaching a maximum of +14.7 /sup 0///sub 00/ versus SMOW, this last value being the highest found in steam samples. This composition can be explained as a consequence of the isotopic exchange at high temperature between limestones and a mixture of marine and local meteoric waters. This interpretation agrees with previous geological and geophysical studies which consider that a promising geothermal field could exist in Lanzarote. (auth)

Spectral factorization using the delta operator

DEFF Research Database (Denmark)

Rostgaard, Morten; Poulsen, Niels Kjølstad; Ravn, Ole

1994-01-01

In recent years many papers have been published abouth the gamma-operator, mostly caused by the better numerical properties and the rapprochement between continuous and discrete time. A major problem within the LQG-design of a delta-based input-output relation has been how to spectral-factorize...... solution to the spectral factorization problem. The key idea is to use the gamma-operator resembled by its behavior to the differential operator....... in an efficient way. The discrete-time method of Kuccera will not be applied since numerical word-length characteristics will be poor for fast sampling rates. In this paper a new approach is considered. A new gamma-operator (Tustin operator) is introduced, in order to make an iterative and numerical stable...

River Delta Subsidence Measured with Interferometric Synthetic Aperture Radar (InSAR)

Science.gov (United States)

Higgins, Stephanie

This thesis addresses the need for high-resolution subsidence maps of major world river deltas. Driven by a combination of rising water, sediment compaction, and reduced sediment supply due to damming and flood control, many deltas are sinking relative to sea level. A lack of data constraining rates and patterns of subsidence has made it difficult to determine the relative contributions of each factor in any given delta, however, or to assess whether the primary drivers of land subsidence are natural or anthropogenic. In recent years, Interferometric Synthetic Aperture Radar (InSAR) has emerged as a satellite-based technique that can map ground deformation with mm-scale accuracy over thousands of square kilometers. These maps could provide critical insight into the drivers of subsidence in deltas, but InSAR is not typically applied to non-urban delta areas due to the difficulties of performing the technique in wet, vegetated settings. This thesis addresses those difficulties and achieves high-resolution measurements of ground deformation in rural deltaic areas. Chapter 1 introduces the processes that drive relative sea level rise in river deltas and investigates open questions in delta subsidence research. Chapter 2 assesses the performance of InSAR in delta settings and reviews interferogram generation in the context of delta analysis, presenting delta-specific processing details and guiding interpretation in these challenging areas. Chapter 3 applies Differential (D-) InSAR to the coast of the Yellow River Delta in China. Results show that subsidence rates are as high as 250 mm/y due to groundwater extraction at aquaculture facilities, a rate that exceeds local and global average sea level rise by nearly two orders of magnitude and suggests a significant hazard for Asian megadeltas. Chapter 4 applies interferometric stacking and Small Baseline Subset (SBAS)-InSAR to the Ganges-Brahmaputra Delta, Bangladesh. Results show that stratigraphy controls subsidence in

The Great Diversion: Danube Delta under Human Control (Invited)

Science.gov (United States)

Giosan, L.

2009-12-01

Many deltas around the world are suffering from sediment deficits that render them unstable to current and predicted rates of sea level rise. One solution proposed to alleviate the complete or partial drowning of such deltas is the use of river diversions to increase the quantity of sediment supplied to the delta plain to support marsh accretion. We examine the results of a half century old program of diversion in the Danube delta that led to the creation of an extensive diversion channel network akin in scope and size to a natural deltaic network. Danube’s importance as a shipping route increased after the Crimean War in the 1850s; the European Danube Commission was charged with maintaining the Sulina distributary as a shipping channel until 1940s. In the same period, several canals were dug to aid fishing in lakes and bring freshwater to brackish lagoons. After World War II, Communist authorities dramatically increased the number of canals for fishing, fish-farming and reed harvesting. New data on sedimentation rates and estimates of sediment fluxes suggest that the intensive canalization in the second half of the 20th Century led to increased sediment deposition that compensated the decreasing sediment discharge linked to damming within the internal fluvial part of the delta; however, the external marine delta has become increasingly sediment starved during the same interval. We emphasize the similarities and contrasts between the “human-controlled” and natural deltaic channel networks of the Danube delta and discuss the sustainability of the delta as a sediment budget problem within a sea level rise context.

Population dynamics, delta vulnerability and environmental change: comparison of the Mekong, Ganges–Brahmaputra and Amazon delta regions

OpenAIRE

Szabo, S.; Brondizio, E.; Renaud, F.G.; Hetrick, S.; Nicholls, R.; Matthews, Z.; Tessler, Z; Tejedor, A; Sebesvari, Z; Foufoula-Georgiou, E; da Costa, S; Dearing, J.A.

2016-01-01

Tropical delta regions are at risk of multiple threats including relative sea level rise and human alterations, making them more and more vulnerable to extreme floods, storms, surges, salinity intrusion, and other hazards which could also increase in magnitude and frequency with a changing climate. Given the environmental vulnerability of tropical deltas, understanding the interlinkages between population dynamics and environmental change in these regions is crucial for ensuring efficient pol...

Succession after fire: variation in \\delta13C of organic tissues and respired CO2 in boreal forests

Science.gov (United States)

Fessenden, J. E.; Li, H.; Mack, M.; Schuur, T.; Warren, S.; Randerson, J. T.

2001-12-01

Isotope ratios of carbon dioxide and leaf organic matter were measured in 5 neighboring forests of varying ages: 7, 14, 45, 140, and 160 years. These forests are composed primarily of black spruce (Picea Mariana) and quaking aspen (Populus tremuloides) with a shift in species dominance from aspen to spruce 50 years after fire disturbance. Research on the carbon isotope ratios of leaf material and CO2 was conducted to look for influences from species composition, forest age, and time after most recent burn. Samples of organic \\delta13C in whole leaf tissue were collected from the dominant species of each forest. Concurrent aboveground NPP measurements allowed us to estimate total ecosystem \\delta13C by providing a method for weighting \\delta13C of individual species and plant tissues. \\delta13CO2 and [CO2] were measured on canopy CO2 to determine the isotopic ratio of ecosystem respiration. The atmospheric results indicated that the \\delta13C of ecosystem respiration changes with successional stage. Specifically, the aspen dominating forests showed 13C depleted values relative to the spruce dominated forests. Organic results showed more 13C-enriched values with increased forest age and vegetation functional type. Specifically, oldest trees within the coniferous species had the most 13C-enriched values in leaf tissues. These results suggest that increases in the disturbance regime of northern boreal forests will lead to a decrease in the \\delta13C of ecosystem carbon with consequences for the atmospheric \\delta13C budget.

Assessing the use of delta C-13 natural abundance in separation of root and microbial respiration in a Danish beech (¤Fagus Sylvatica¤ L.) forest

DEFF Research Database (Denmark)

Formanek, P.; Ambus, P.

2004-01-01

on the root respiration contribution to total CO2 effluxes. The delta(13)C isotopic analyses Of CO2 were performed using a FinniganMAT Delta(PLUS) isotope-ratio mass spectrometer coupled in continuous flow mode to a trace gas preparation-concentration unit (PreCon). Gas samples in 2-mL crimp seal vials were...... samples are not representative for the C-pools actively undergoing decomposition. Copyright (C) 2004 John Wiley Sons, Ltd....

Stable Isotope (delta OXYGEN-18, Delta Deuterium, Delta CARBON-13) Dendroclimatological Studies in the Waterloo Region of Southern Ontario, Canada, Between AD 1610 and 1990.

Science.gov (United States)

Buhay, William Mark

Oxygen (delta^{18} O), hydrogen (delta^2H) and carbon (delta^{13}C) isotopes were measured in wood cellulose from elm, white pine and maple trees that grew in southwestern Ontario, Canada. The measured oxygen and hydrogen isotopic data were used for model-based reconstructions of delta^{18}{O}_{meteoric water}, mean annual temperature (MAT) and relative humidity for a period, AD 1610 to 1880, that precedes instrumental records of climate. The carbon isotope measurements were compared with the Cellulose Model inferred climate data to reveal additional environmental information. Modifications made to the Cellulose Model focused on the dynamics of oxygen and hydrogen isotopic fractionation in plants during evapotranspiration and photosynthetic assimilation. For instance, kinetic fractionation of ^{18}O was found to be predictable from theoretical considerations of leaf energy balance and boundary layer dynamics. Kinetic fractionation during evapotranspiration is sensitive to the nature of the boundary layer, which is controlled by leaf size and morphology. Generally, plants with small segmented leaves have a lower component of turbidity in the leaf boundary layer, which results in higher kinetic fractionation values, than do plants having large simple leaves and more turbulent boundary layers. Kinetic ^2H enrichment in plant leaf water can also be rationalized in terms of leaf size and morphology when an apparent temperature-dependent isotope effect, acting in opposition to evaporative enrichment, is taken into account. Accounting for this temperature -dependent isotope effect helps to: (1) reconcile hydrogen kinetic fractionation inconsistencies for different leaves; (2) explain a temperature effect previously attributed to variable biochemical fractionation during cellulose synthesis, and; (3) verify hydrogen biochemical effects in plants. This improved characterization of the oxygen and hydrogen isotopic effects in plants, using the modified Cellulose Model, helped

Performance of the inverse photoemission spectrometer with a new bandpass photon detector of narrow bandwidth and high sensitivity

International Nuclear Information System (INIS)

Ueda, Yoshifumi; Nishihara, Katsuhiro; Mimura, Kojiro; Hari, Yasuko; Taniguchi, Masaki; Fujisawa, Masami

1993-01-01

A combination of a SrF 2 entrance window and a photomultiplier with the Cu-BeO first dynode coated with KCl film realizes the bandpass photon detector with the FWHM of 0.47 eV centered at 9.43 eV and the sensitivity improved by about one order of magnitude in comparison with the detector without the KCl film. The overall energy resolution of the inverse photoemission spectrometer consisting of an electron gun with a BaO cathode and the new detector has been estimated to be 0.56 eV using polycrystalline Au. Typical counting rate is 10 2 -10 3 counts/(μA s) for unoccupied states near the Fermi level of the Au at an acceptance angle of about 0.8π sr with an Al collecting mirror. (orig.)

A simple encoding method for Sigma-Delta ADC based biopotential acquisition systems.

Science.gov (United States)

Guerrero, Federico N; Spinelli, Enrique M

2017-10-01

Sigma Delta analogue-to-digital converters allow acquiring the full dynamic range of biomedical signals at the electrodes, resulting in less complex hardware and increased measurement robustness. However, the increased data size per sample (typically 24 bits) demands the transmission of extremely large volumes of data across the isolation barrier, thus increasing power consumption on the patient side. This problem is accentuated when a large number of channels is used as in current 128-256 electrodes biopotential acquisition systems, that usually opt for an optic fibre link to the computer. An analogous problem occurs for simpler low-power acquisition platforms that transmit data through a wireless link to a computing platform. In this paper, a low-complexity encoding method is presented to decrease sample data size without losses, while preserving the full DC-coupled signal. The method achieved a 2.3 average compression ratio evaluated over an ECG and EMG signal bank acquired with equipment based on Sigma-Delta converters. It demands a very low processing load: a C language implementation is presented that resulted in an 110 clock cycles average execution on an 8-bit microcontroller.

Metallicism and pulsation: an analysis of the delta Delphini stars

International Nuclear Information System (INIS)

Kurtz, D.W.

1976-01-01

Fine abundance analyses of seven delta Delphini stars and one delta Scuti star relative to four comparison standards are presented. Five of the delta Del stars are shown to have abundances most similar to the evolved Am stars. It is argued that these abundances are different from the classical Am star and Ap star abundances and that similarities to the Ba II star abundances are coincidental. We suggest that the anomalous abundance delta Del stars are evolved metallic line stars on the basis of their abundances, position in the β, M/sub v/ plane, inferred rotational velocities, and perhaps their binary incidence. Some of the delta Del stars are delta Scuti pulsators. We argue that pulsation and metallicism are mutually exclusive among the classical Am stars but may coexist in other stars related to the classical Am stars. A preference for the diffusion hypothesis model for the metallic line stars is stated and supported and the implications of the coexistence of pulsation and diffusion are discussed

Groundwater Flow Model of Göksu Delta Coastal Aquifer System

Science.gov (United States)

Erdem Dokuz, Uǧur; Çelik, Mehmet; Arslan, Şebnem; Engin, Hilal

2016-04-01

Like many other coastal areas, Göksu Delta (Mersin-Silifke, Southern Turkey) is a preferred place for human settlement especially due to its productive farmlands and water resources. The water dependent ecosystem in Göksu delta hosts about 332 different plant species and 328 different bird species besides serving for human use. Göksu Delta has been declared as Special Environmental Protection Zone, Wildlife Protection Area, and RAMSAR Convention for Wetlands of International Importance area. Unfortunately, rising population, agricultural and industrial activities cause degradation of water resources both by means of quality and quantity. This problem also exists for other wetlands around the world. It is necessary to prepare water management plans by taking global warming issues into account to protect water resources for next generations. To achieve this, the most efficient tool is to come up with groundwater management strategies by constructing groundwater flow models. By this aim, groundwater modeling studies were carried out for Göksu Delta coastal aquifer system. As a first and most important step in all groundwater modeling studies, geological and hydrogeological settings of the study area have been investigated. Göksu Delta, like many other deltaic environments, has a complex structure because it was formed with the sediments transported by Göksu River throughout the Quaternary period and shaped throughout the transgression-regression periods. Both due to this complex structure and the lack of observation wells penetrating deep enough to give an idea of the total thickness of the delta, it was impossible to reveal out the hydrogeological setting in a correct manner. Therefore, six wells were drilled to construct the conceptual hydrogeological model of Göksu Delta coastal aquifer system. On the basis of drilling studies and slug tests that were conducted along Göksu Delta, hydrostratigraphic units of the delta system have been obtained. According to

Polarization-selective infrared bandpass filter based on a two-layer subwavelength metallic grating

Science.gov (United States)

Hohne, Andrew J.; Moon, Benjamin; Baumbauer, Carol L.; Gray, Tristan; Dilts, James; Shaw, Joseph A.; Dickensheets, David L.; Nakagawa, Wataru

2017-08-01

We present the design, fabrication, and characterization of a polarization-selective infrared bandpass filter based on a two-layer subwavelength metallic grating for use in polarimetric imaging. Gold nanowires were deposited via physical vapor deposition (PVD) onto a silicon surface relief grating that was patterned using electron beam lithography (EBL) and fabricated using standard silicon processing techniques. Optical characterization with a broad-spectrum tungsten halogen light source and a grating spectrometer showed normalized peak TM transmission of 53% with a full-width at half-maximum (FWHM) of 122 nm, which was consistent with rigorous coupled-wave analysis (RCWA) simulations. Simulation results suggested that device operation relied on suppression of the TM transmission caused by surface plasmon polariton (SPP) excitation at the gold-silicon interface and an increase in TM transmission caused by a Fabry-Perot (FP) resonance in the cavity between the gratings. TE rejection occurred at the initial air/gold interface. We also present simulation results of an improved design based on a two-dielectric grating where two different SPP resonances allowed us to improve the shape of the passband by suppressing the side lobes. This newer design resulted in improved side-band performance and increased peak TM transmission.

Mesquite Risk Mapping and Assessment in Tokar Delta-Eastern Sudan

OpenAIRE

Suliman, Mahgoub; NAWATA, Hiroshi; Hoshino, Buho; Karamalla, Abdelaziz

2015-01-01

Tokar Delta is a name given to a small delta of approximately 161,000 hectares situated in the southern area of the Red Sea in Eastern Sudan. Beginning of 1980, mesquite species (Prosopis chilensis & Prosopis juliflora) were introduced to Tokar area to be planted as a shelterbelt for the city Tokar, but after while; it spread out to the delta area and became an invasive plant to the agricultural lands and along Khor Barak banks. Nowadays mesquite covers more than half of the delta area, decre...

(p,. pi. /sup -/) reaction and. delta. /sup + +/ components of nuclei

Energy Technology Data Exchange (ETDEWEB)

Kisslinger, L S; Miller, G A [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics

1975-12-08

The use of the (p,..pi../sup -/) reaction as a probe to determine ..delta../sup + +/(1232) components of nuclear wave functions is examined within the framework of a model which treats baryon resonances on the same footing as nucleons. Nuclear structure properties which affect the ..delta..-probability are discussed. Estimates of cross sections, at several energies, are made for the ..delta../sup + +/ transfer contribution as well as for the competing processes: proton charge exchange (p,n) followed by an (n,..gamma../sup -/) reaction; emission of a ..pi../sup 0/ followed by pion charge exchange (..pi../sup -/,..pi../sup 0/). Even with ..delta..-probabilities as small as 0.0001 the ..delta..-transfer process can compete with ordinary background charge-exchange reactions.

Sediment-hosted contaminants and distribution patterns in the Mississippi and Atchafalaya River Deltas

Science.gov (United States)

Flocks, James G.; Kindinger, Jack G.; Ferina, Nicholas; Dreher, Chandra

2002-01-01

The Mississippi and Atchafalaya Rivers transport very large amounts of bedload and suspended sediments to the deltaic and coastal environments of the northern Gulf of Mexico. Absorbed onto these sediments are contaminants that may be detrimental to the environment. To adequately assess the impact of these contaminants it is first necessary to develop an understanding of sediment distribution patterns in these deltaic systems. The distribution patterns are defined by deltaic progradational cycles. Once these patterns are identified, the natural and industrial contaminant inventories and their depositional histories can be reconstructed. Delta progradation is a function of sediment discharge, as well as channel and receiving-basin dimensions. Fluvial energy controls the sediment distribution pattern, resulting in a coarse grained or sandy framework, infilled with finer grained material occupying the overbank, interdistributary bays, wetlands and abandoned channels. It has been shown that these fine-grained sediments can carry contaminants through absorption and intern them in the sediment column or redistribute them depending on progradation or degradation of the delta deposit. Sediment distribution patterns in delta complexes can be determined through high-resolution geophysical surveys and groundtruthed with direct sampling. In the Atchafalaya and Mississippi deltas, remote sensing using High-Resolution Single-Channel Seismic Profiling (HRSP) and Sidescan Sonar was correlated to 20-ft vibracores to develop a near-surface geologic framework that identifies variability in recent sediment distribution patterns. The surveys identified bedload sand waves, abandoned-channel back-fill, prodelta and distributary mouth bars within the most recently active portions of the deltas. These depositional features respond to changes in deltaic processes and through their response may intern or transport absorbed contaminants. Characterizing these features provides insight into the

Population decline in the Delta caribou herd with reference to other Alaskan herds

Directory of Open Access Journals (Sweden)

Patrick Valkenburg et al.

1996-01-01

Full Text Available After growing continuously for nearly 15 years, the Delta caribou herd began to decline in 1989. Most other Interior Alaskan herds also began declining. In the Delta herd, and in other herds, the declines were caused primarily by high summer mortality of calves and increased natural mortality of adult females. Other minor causes included increased winter mortality of calves, and reduced parturition rates of 3-year-old and older females. The decline in the Delta herd also coincided with increased wolf (Canis lupus numbers, winters with deeper than normal snow, and warm summers. Mean body weight of annual samples of 10-month-old female calves was consistently low during the decline. Except in some of the smallest Interior Alaskan herds, we conclude that evidence for population regulation in Alaskan caribou is weak, and that herds are likely to fluctuate within a wide range of densities due to complex interactions of predation and weather. Unless wolf numbers are influenced by man, the size of a caribou herd in a given year is likely to be largely a function of its size during the previous population low and the number of years of favorable weather in the interim.

Total mercury concentrations in surface water and sediments from Danube Delta lakes

Directory of Open Access Journals (Sweden)

TEODOROF Liliana

2007-10-01

Full Text Available The samples were collected from surface water and sediments of Danube Delta lakes, during april and may 2006. The sediments were digested with nitric acid, and the surface water with real aqua, at Microwave Oven Anton Paar and analised at FIMS 400 Perkin Elmer. The results show that the total mercury is compared with the maximum allowed limits according with Normative 161/2006.

Polarized antiquark flavor asymmetry DELTA anti u(x)-DELTA anti d(x) and the pion cloud

CERN Document Server

Fries, R J; Weiss, C

2003-01-01

The flavor asymmetry of the unpolarized antiquark distributions in the proton, anti u(x)- anti d(x)0. Using a simple chiral linear sigma model as an example, we demonstrate that in the meson cloud picture a large positive DELTA anti u(x)-DELTA anti d(x) can be obtained from pi-sigma interference contributions. This calls into question previous estimates based on rho-meson contributions alone, and indicates how the results of the meson cloud picture may be reconciled with those of quark-based models. (orig.)

An improved ultra-wideband bandpass filter design using split ring resonator with coupled microstrip line

Science.gov (United States)

Umeshkumar, Dubey Suhmita; Kumar, Manish

2018-04-01

This paper incorporates an improved design of Ultra Wideband Bandpass filter by using split ring resonators (SRR) along with the coupled microstrip lines. The use of split ring resonators and shunt step impedance open circuit stub enhances the stability due to transmission zeroes at the ends. The designing of filter and simulation of parameters is carried out using Ansoft's HFSS 13.0 software on RT/Duroid 6002 as a substrate with dielectric constant of 2.94. The design utilizes a frequency band from 22GHz to 29GHz. This band is reserved for Automotive Radar system and sensors as per FCC specifications. The proposed design demonstrates insertion loss less than 0.6dB and return loss better than 12dB at mid frequency i.e. 24.4GHz. The reflection coefficient shows high stability of about 12.47dB at mid frequency. The fractional bandwidth of the proposed filter is about 28.7% and size of filter design is small due to thickness of 0.127mm.

Glomerular barrier behaves as an atomically precise bandpass filter in a sub-nanometre regime

Science.gov (United States)

Du, Bujie; Jiang, Xingya; Das, Anindita; Zhou, Qinhan; Yu, Mengxiao; Jin, Rongchao; Zheng, Jie

2017-11-01

The glomerular filtration barrier is known as a 'size cutoff' slit, which retains nanoparticles or proteins larger than 6-8 nm in the body and rapidly excretes smaller ones through the kidneys. However, in the sub-nanometre size regime, we have found that this barrier behaves as an atomically precise 'bandpass' filter to significantly slow down renal clearance of few-atom gold nanoclusters (AuNCs) with the same surface ligands but different sizes (Au18, Au15 and Au10-11). Compared to Au25 (∼1.0 nm), just few-atom decreases in size result in four- to ninefold reductions in renal clearance efficiency in the early elimination stage, because the smaller AuNCs are more readily trapped by the glomerular glycocalyx than larger ones. This unique in vivo nano-bio interaction in the sub-nanometre regime also slows down the extravasation of sub-nanometre AuNCs from normal blood vessels and enhances their passive targeting to cancerous tissues through an enhanced permeability and retention effect. This discovery highlights the size precision in the body's response to nanoparticles and opens a new pathway to develop nanomedicines for many diseases associated with glycocalyx dysfunction.

Investigation of New Microstrip Bandpass Filter Based on Patch Resonator with Geometrical Fractal Slot.

Directory of Open Access Journals (Sweden)

Yaqeen S Mezaal

Full Text Available A compact dual-mode microstrip bandpass filter using geometrical slot is presented in this paper. The adopted geometrical slot is based on first iteration of Cantor square fractal curve. This filter has the benefits of possessing narrower and sharper frequency responses as compared to microstrip filters that use single mode resonators and traditional dual-mode square patch resonators. The filter has been modeled and demonstrated by Microwave Office EM simulator designed at a resonant frequency of 2 GHz using a substrate of εr = 10.8 and thickness of h = 1.27 mm. The output simulated results of the proposed filter exhibit 22 dB return loss, 0.1678 dB insertion loss and 12 MHz bandwidth in the passband region. In addition to the narrow band gained, miniaturization properties as well as weakened spurious frequency responses and blocked second harmonic frequency in out of band regions have been acquired. Filter parameters including insertion loss, return loss, bandwidth, coupling coefficient and external quality factor have been compared with different values of perturbation dimension (d. Also, a full comparative study of this filter as compared with traditional square patch filter has been considered.

Delta agent (Hepatitis D)

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/000216.htm Hepatitis D (Delta agent) To use the sharing features on this page, please enable JavaScript. Hepatitis D is a viral infection caused by the ...

Effects of local and spatial conditions on the quality of harvested rainwater in the Mekong Delta, Vietnam

International Nuclear Information System (INIS)

Wilbers, Gert-Jan; Sebesvari, Zita; Rechenburg, Andrea; Renaud, Fabrice G.

2013-01-01

The objective of this study was to assess the quality of harvested rainwater in the Mekong Delta (MD), Vietnam for local (roof types, storage system and duration) and spatial (proximity of industry, main roads, coastline) conditions. 78 harvested rainwater samples were collected in the MD and analyzed for pH, turbidity, TDS, COD, nutrients (NH 4 , NO 3 , NO 2 , o-PO 4 ), trace metals and coliforms. The results show that thatch roofs lead to an increase of pollutants like COD (max 23.2 mgl −1 ) and turbidity (max 10.1 mgl −1 ) whereas galvanized roofs lead to an increase of Zn (max 2.2 mgl −1 ). The other local and spatial parameters had no or only minor influence on the quality of household harvested rainwater. However, lead (Pb) (max. 16.9 μgl −1 ) and total coliforms (max. 102 500 CFU100 ml −1 ) were recorded at high concentrations, probably due to a variety of household-specific conditions such as rainwater storage, collection and handling practices. -- Highlights: •Rainwater is a main drinking water source in the Mekong Delta. •Harvested rainwater is severely polluted for turbidity, lead and (total) coliforms. •Roof types significantly affect the quality of harvested rainwater. •Effects of household conditions on harvested rainwater quality should be further assessed. •Harvested rainwater is in potential a safe drinking water resource in the Mekong Delta. -- Concentrations of lead and total coliforms in household-harvested rainwater in the Mekong Delta exceed drinking water guidelines in 17% and 92% of the samples, respectively

Sigma-delta modulator modeling analysis and design

International Nuclear Information System (INIS)

Ge Binjie; Wang Xin'an; Zhang Xing; Feng Xiaoxing; Wang Qingqin

2010-01-01

This paper introduces a new method for SC sigma-delta modulator modeling. It studies the integrator's different equivalent circuits in the integrating and sampling phases. This model uses the OP-AMP input pair's tail current (I 0 ) and overdrive voltage (v on ) as variables. The modulator's static and dynamic errors are analyzed. A group of optimized I 0 and v on for maximum SNR and power x area ratio can be obtained through this model. As examples, a MASH21 modulator for digital audio and a second order modulator for RFID baseband are implemented and tested, and they can achieve 91 dB and 72 dB respectively, which verifies the modeling and design criteria. (semiconductor integrated circuits)

Hepatitis delta in HIV-infected individuals in Europe

DEFF Research Database (Denmark)

Soriano, Vincent; Grint, Daniel; Monforte, Antonellad'arminio

2011-01-01

BACKGROUND:: Hepatitis delta virus (HDV) infection results in the most aggressive form of chronic viral hepatitis. There is scarce information about the prevalence, epidemiology, virological profile and natural historyof hepatitis delta in HIV patients. METHODS:: From 16,597 HIV patients enrolled......-RNA was quantified using a real-time PCR method. RESULTS:: A total of 61/422 HBsAg+ carriers were anti-HDV+ (prevalence: 14.5%). Hepatitis delta predominated in intravenous drug users and for this reason in South and/or East Europe. Serum HDV-RNA was detectable in 87% of tested anti-HDV+ patients, with a median...... titer of 1.76x10¿copies/ml. Overall, delta hepatitis patients showed lower serum HBV-DNA than the rest of HBsAg+ carriers, although the inhibitory effect of HDV on HBV replication was not recognized in HBV genotype D patients.Whereas HDV was not associated with progression to AIDS, it significantly...

Paleomagnetic constrains in the reconstruction of the recent stratigraphic evolution of the Po delta

Science.gov (United States)

Correggiari, Annamaria; Vigliotti, Luigi; Remia, Alessandro; Perini, Luisa; Calabrese, Lorenzo; Luciani, Paolo

2014-05-01

The delta and prodelta deposits are characterized by a complex stratigraphic architecture that can be approached with several multidisciplinary tools. We present an example from the Po delta system characterized by alternating phases of rapid advance and abandonment of its multiple deltaic lobes that has been investigated through: (1) a review of historical cartography extending back several centuries; (2) integrated surveys of VHR seismic profiles recorded offshore of the modern delta from water depths as shallow as 5 m to the toe of the prodelta in about 30 m; and (3) sedimentological and geochronological data from precisely positioned sediment cores. Within this well known stratigraphic framework we have acquired seismic data and sediment cores in the area of the post roman Po delta system. However a precise dating of the recent evolution of depositional delta lobes is difficult because of the lack of suitable dating methods. To constrain the emplacement timing of the Renaissance lobes a paleomagnetic studies was carried out on a sedimentary sequence representing a seismic facies well correlated in the cores by whole core magnetic susceptibility profile. Forty eight samples were collected from a core section (RER96-1) characterized by a fine grained lithology suitable for paleomagnetic investigations. The characteristic remanent magnetization (ChRM) of the sediments has been obtained by applying an AF cleaning between 10 and 30 millitesla. The results have been compared with the directions recorded by the historical lavas of the Etna and Vesuvius. The combination of the trends observed in the declination and inclination suggests that the results can be compatible with the directions of the secular variation of the earth magnetic field occurring during the XVII century. This allow to date the sismic unit as representative of the beginning of the new delta following the Porto Viro avulsion made by the Venice Republic in 1604 AD. This delta history reflects the

Within-canopy and ozone fumigation effects on delta13C and Delta18O in adult beech (Fagus sylvatica) trees: relation to meteorological and gas exchange parameters.

Science.gov (United States)

Gessler, Arthur; Löw, Markus; Heerdt, Christian; de Beeck, Maarten Op; Schumacher, Johannes; Grams, Thorsten E E; Bahnweg, Günther; Ceulemans, Reinhart; Werner, Herbert; Matyssek, Rainer; Rennenberg, Heinz; Haberer, Kristine

2009-11-01

In this study, the effects of different light intensities either in direct sunlight or in the shade crown of adult beech (Fagus sylvatica L.) trees on delta13C and Delta18O were determined under ambient (1 x O3) and twice-ambient (2 x O3) atmospheric ozone concentrations during two consecutive years (2003 and 2004). We analysed the isotopic composition in leaf bulk, leaf cellulose, phloem and xylem material and related the results to (a) meteorological data (air temperature, T and relative humidity, RH), (b) leaf gas exchange measurements (stomatal conductance, g(s); transpiration rate, E; and maximum photosynthetic activity, A(max)) and (c) the outcome of a steady-state evaporative enrichment model. Delta13C was significantly lower in the shade than in the sun crown in all plant materials, whilst Delta18O was increased significantly in the shade than in the sun crown in bulk material and cellulose. Elevated ozone had no effect on delta13C, although Delta18O was influenced by ozone to varied degrees during single months. We observed significant seasonal changes for both parameters, especially in 2004, and also significant differences between the study years. Relating the findings to meteorological data and gas exchange parameters, we conclude that the differences in Delta18O between the sun and the shade crown were predominantly caused by the Péclet effect. This assumption was supported by the modelled Delta18O values for leaf cellulose. It was demonstrated that independent of RH, light-dependent reduction of stomatal conductance (and thus transpiration) and of A(max) can drive the pattern of Delta18O increase with the concomitant decrease of delta13C in the shade crown. The effect of doubling ozone levels on time-integrated stomatal conductance and transpiration as indicated by the combined analysis of Delta18O and delta13C was much lower than the influence caused by the light exposure.

The Niger Delta Crisis

African Journals Online (AJOL)

chifaou.amzat

2013-09-28

Sep 28, 2013 ... Department of History & International Studies, Delta State University, Abraka,. Nigeria. .... democracy implies popular power. That is ... Okonta (2006:5) draws attention to Anna Zalik's treatise called 'Petro-Vio- lence' and ...

3D lumped components and miniaturized bandpass filter in an ultra-thin M-LCP for SOP applications

KAUST Repository

Arabi, Eyad A.

2013-01-01

In this work, a library of 3D lumped components completely embedded in the thinnest, multilayer LCP (M-LCP) stack- up with four metallization layers and 100 μm of total thickness, is reported for the first time. A vertically and horizontally interdigitated capacitor, realized in this stack-up, provides higher self resonant frequency as compared to a similarly sized conventional parallel plate capacitor. Based on the above mentioned library, a miniaturized bandpass filter is presented for the GPS application. It utilizes mutually coupled inductors and is the smallest reported in the literature with a size of (0.035×0.028×0.00089)λg. Finally, the same filter realized in a competing ceramic technology (LTCC) is compared in performance with the ultra-thin M-LCP design. The M-LCP module presented in this work is inherently exible and offers great potential for wearable and conformal applications.

T gamma/delta lymphocytes in renal transplant recipients

NARCIS (Netherlands)

Raasveld, M. H.; Bloemena, E.; Surachno, S.; ten Berge, R. J.

1992-01-01

T gamma/delta lymphocytes are able to perform allospecific cytotoxicity and natural killer cytotoxicity in vitro. However, very little is known about their function in vivo. To investigate the possible involvement of T gamma/delta lymphocytes in the immune response to renal allografts, fine-needle

An integrated assessment framework for land subsidence in delta cities

Directory of Open Access Journals (Sweden)

T. H. M. Bucx

2015-11-01

Full Text Available In many delta cities land subsidence exceeds absolute sea level rise up to a factor of ten by excessive groundwater extraction related to rapid urbanization and population growth. Without change, parts of Jakarta, Ho Chi Minh City, Bangkok and numerous other delta (and coastal cities will sink below sea level. Increased flooding and also other widespread impacts of land subsidence result already in damage of billions of dollars per year. In order to gain insight in the complex, multi-sectoral aspects of subsidence, to raise awareness and to support decision making on appropriate adaptation strategies and measures, an Integrated Assessment Framework (IAF for subsidence is introduced, illustrated by several (delta case studies. Based on that a list of 10 generic key issues and possible solutions is presented in order to further develop and support a (generic approach how to deal with subsidence in current and future subsidence-prone areas. For exchange of experiences and knowledge development.on subsidence in deltas the Delta Alliance, a knowledge network of deltas worldwide, can be supportive.

Delta ferrite in the weld metal of reduced activation ferritic martensitic steel

Energy Technology Data Exchange (ETDEWEB)

Sam, Shiju, E-mail: shiju@ipr.res.in [Institute for Plasma Research, Gandhinagar, Gujarat 382 428 (India); Das, C.R.; Ramasubbu, V.; Albert, S.K.; Bhaduri, A.K.; Jayakumar, T. [Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Rajendra Kumar, E. [Institute for Plasma Research, Gandhinagar, Gujarat 382 428 (India)

2014-12-15

Formation of delta(δ)-ferrite in the weld metal, during autogenous bead-on-plate welding of Reduced Activation Ferritic Martensitic (RAFM) steel using Gas Tungsten Arc Welding (GTAW) process, has been studied. Composition of the alloy is such that delta-ferrite is not expected in the alloy; but examination of the weld metal revealed presence of delta-ferrite in the weld metal. Volume fraction of delta-ferrite is found to be higher in the weld interface than in the rest of the fusion zone. Decrease in the volume fraction of delta-ferrite, with an increase in preheat temperature or with an increase in heat input, is observed. Results indicate that the cooling rate experienced during welding affects the volume fraction of delta-ferrite retained in the weld metal and variation in the delta-ferrite content with cooling rate is explained with variation in the time that the weld metal spends in various temperature regimes in which delta-ferrite is stable for the alloy during its cooling from the liquid metal to the ambient temperature. This manuscript will discuss the effect of welding parameters on formation of delta-ferrite and its retention in the weld metal of RAFM steel.

HIV/AIDS, artisanal fishing and food security in the Okavango Delta, Botswana

Science.gov (United States)

Ngwenya, B. N.; Mosepele, K.

Generally, rural households pursue all year round natural and non-natural resource-based livelihood systems to diversify these options in order to cope with risks emanating from a range of shocks and stressors. Artisanal fishing in the Delta is not only a major livelihood option but also a source of food security. This paper is based on analysis of primary data collected from a survey of 248 subsistence fishers’ households through simple random sampling in 22 villages in the Delta. The overall objectives of the survey were to assess the general prevalence of HIV/AIDS in the Ngamiland district of Botswana, to investigate potential effects of AIDS-related stressors, particularly chronic illness on artisanal fishing activities, and to assess implications towards food security. Results from this study indicate that HIV prevalence rates for pregnant women attending antenatal clinics in the Delta are approximately 30% and are related to factors such as marriage, education, and employment. Despite this relatively high prevalence percentage, most of the affected households do not have adequate access to HIV/AIDS support facilities. Support services are provided on the basis of population size and/or status of the settlement (i.e. urban, urban village, rural or remote). Therefore, since about 50% of the Delta’s population lives in settlements of less than 500 people, they receive health services indirectly through major population centres whose capacity to deliver timely HIV/AIDS services is limited. This disproportionate access to HIV/AIDS services disadvantages the majority of fishing communities in the Delta, and may affect their ability to fish. Moreover, about 53% of sampled households had cared for a continuously ill person/s (CIP’s) in the last 5 years, out of which approximately 29% felt that this seriously impacted fishing activities. These serious impacts included sale of family assets, depletion of savings, and switching or abandoning fishing activities

Delta count-rate monitoring system

International Nuclear Information System (INIS)

Van Etten, D.; Olsen, W.A.

1985-01-01

A need for a more effective way to rapidly search for gamma-ray contamination over large areas led to the design and construction of a very sensitive gamma detection system. The delta count-rate monitoring system was installed in a four-wheel-drive van instrumented for environmental surveillance and accident response. The system consists of four main sections: (1) two scintillation detectors, (2) high-voltage power supply amplifier and single-channel analyzer, (3) delta count-rate monitor, and (4) count-rate meter and recorder. The van's 6.5-kW generator powers the standard nuclear instrument modular design system. The two detectors are mounted in the rear corners of the van and can be run singly or jointly. A solid-state bar-graph count-rate meter mounted on the dashboard can be read easily by both the driver and passenger. A solid-state strip chart recorder shows trends and provides a permanent record of the data. An audible alarm is sounded at the delta monitor and at the dashboard count-rate meter if a detected radiation level exceeds the set background level by a predetermined amount

Carbon storage in the Mississippi River delta enhanced by environmental engineering

Science.gov (United States)

Shields, Michael R.; Bianchi, Thomas S.; Mohrig, David; Hutchings, Jack A.; Kenney, William F.; Kolker, Alexander S.; Curtis, Jason H.

2017-11-01

River deltas have contributed to atmospheric carbon regulation throughout Earth history, but functioning in the modern era has been impaired by reduced sediment loads, altered hydrologic regimes, increased global sea-level rise and accelerated subsidence. Delta restoration involves environmental engineering via river diversions, which utilize self-organizing processes to create prograding deltas. Here we analyse sediment cores from Wax Lake delta, a product of environmental engineering, to quantify the burial of organic carbon. We find that, despite relatively low concentrations of organic carbon measured in the cores (about 0.4%), the accumulation of about 3 T m-2 of sediment over the approximate 60 years of delta building resulted in the burial of a significant amount of organic carbon (16 kg m-2). This equates to an apparent organic carbon accumulation rate of 250 +/- 23 g m-2 yr-1, which implicitly includes losses by carbon emissions and erosion. Our estimated accumulation rate for Wax Lake delta is substantially greater than previous estimates based on the top metre of delta sediments and comparable to those of coastal mangrove and marsh habitats. The sedimentation of carbon at the Wax Lake delta demonstrates the capacity of engineered river diversions to enhance both coastal accretion and carbon burial.

The impact of human activities in the Wulan Delta Estuary, Indonesia

Science.gov (United States)

Fadlillah, L. N.; Sunarto; Widyastuti, M.; Marfai, M. A.

2018-04-01

The increasing of human population in the watershed and the coastal area and the need of life exert pressure in the delta that provides various resources. Wulan Delta is one of active Delta in Central Java, Indonesia. It has been experienced multiple pressures because of natural factors and human factors. In order to provide the scientific solution and to analyze the impact of human intervention in delta, we collected several pieces of evidence based on secondary data and primary data. The secondary data is water quality data on sites 6 and 7, meanwhile the secondary data is the water quality data in site 1 to 5. This paper present a review and problems identification in Wulan Delta, based on hydrological condition, land use, and human activities in the delta. Meanwhile, the human intervention in the land which is land use exchange leads to several problems such as the land use changes, high sediment load, and water degradation. Almost 80% of Delta has been transformed into the fish pond by local communities.

Pesticides in soil and sediment of a dyke-protected area of the Red River Delta, Vietnam

Science.gov (United States)

Braun, Gianna; Bläsing, Melanie; Kruse, Jens; Amelung, Wulf; Renaud, Fabrice; Sebesvari, Zita

2017-04-01

Coastal regions are densely populated but at the same time represent important agricultural areas for food production of the growing world population. To sustain high agricultural yields, in monocultures such as permanent rice systems, pesticides are used in high quantity and frequency. While earlier studies monitored the fate of pesticides in paddy rice systems, the overall fate of these compounds is altered nowadays due to the construction of dykes, which are needed in many delta regions to protect them from high tides, storm surges and salt water intrusion such as in the Red River Delta. The dyke system regulates the discharge and water exchange inside the diked area including irrigation channels for the paddy rice production. Local authorities observed increasing pollution towards the sea (highest pollution close to the dykes) and hypothesized that the dyke system would prevent water exchange and thus lead to an accumulation of pollutants within the diked area. Hence, the purpose of this study was to investigate the effect of dykes on pesticide pollution patterns in coastal delta regions of the Red River Delta. The study was conducted in the district Giao Thuy of the Red River Delta, Vietnam. This area is surrounded by a sea and river dyke; both have several inlet and outlet gates to control the water level in the irrigation channels. We determined the pesticide pollution pattern in a diked agricultural area, as well as along salinity gradients in and outside the diked areas. Samples were taken from rice fields and sediments from irrigation channels inside the diked area as well from saline aquaculture fields located outside the dyke. Pesticide analysis was conducted by accelerated solvent extraction (ASE), followed up by the clean-up process described by Laabs et al. (2007) and analyses using gas chromatography coupled with a mass selective detector (MSD). Preliminary results suggest that out of the 26 analysed compounds chlorpyrifos, propiconazole and

Political Empowerment of Women through Literacy Education Programmes in EDO and Delta States, Nigeria

Science.gov (United States)

Olomukoro, Caroline O.; Adelore, Omobola O.

2015-01-01

The study examined the political empowerment of women through literacy education programmes in Edo and Delta States in the South-South Geopolitical zone of Nigeria. A sample of 1022 women was randomly drawn from the different levels of literacy classes organised by the Agency of Adult and Nonformal Education and non-governmental and private…

Challenges and Approaches in River Delta Planning - report on training workshop

NARCIS (Netherlands)

Wosten, J.H.M.; Douven, W.; Long Phi, H.; Fida Abdullah Khan, M.

2012-01-01

River delta’s, like the Mekong Delta (Vietnam), Ganges-Brahmaputra Delta (Bangladesh), Irrawady (Myanmar) and Ciliwung Delta (Indonesia) are developing rapidly and characterized by large-scale urbanization and industrialization processes. They are facing serious planning challenges related to issues

Diet-tissue stable isotope (delta¹³C and delta¹⁵N) discrimination factors for multiple tissues from terrestrial reptiles (rock iguanas, Cyclura species)

OpenAIRE

Steinitz, Ronnie

2015-01-01

Trophic interactions can drive community structure; therefore, studying food webs is key in understanding ecological communities. Stable isotope analysis is a powerful tool for reconstructing foraging patterns. However, stable isotope discrimination factors (delta¹³C and delta¹⁵N) are needed to best use this tool. We determined the first delta¹³C and delta¹⁵N values for Rock Iguanas (Cyclura spp.) to better understand isotope fractionation patterns in reptiles and estimate wild reptile diets....

Magnitude of arsenic pollution in the Mekong and Red River Deltas - Cambodia and Vietnam

International Nuclear Information System (INIS)

Berg, Michael; Stengel, Caroline; Trang, Pham Thi Kim; Hung Viet, Pham; Sampson, Mickey L.; Leng, Moniphea; Samreth, Sopheap; Fredericks, David

2007-01-01

Large alluvial deltas of the Mekong River in southern Vietnam and Cambodia and the Red River in northern Vietnam have groundwaters that are exploited for drinking water by private tube-wells, which are of increasing demand since the mid-1990s. This paper presents an overview of groundwater arsenic pollution in the Mekong delta: arsenic concentrations ranged from 1-1610 μg/L in Cambodia (average 217 μg/L) and 1-845 μg/L in southern Vietnam (average 39 μg/L), respectively. It also evaluates the situation in Red River delta where groundwater arsenic concentrations vary from 1-3050 μg/L (average 159 μg/L). In addition to rural areas, the drinking water supply of the city of Hanoi has elevated arsenic concentrations. The sediments of 12-40 m deep cores from the Red River delta contain arsenic levels of 2-33 μg/g (average 7 μg/g, dry weight) and show a remarkable correlation with sediment-bound iron. In all three areas, the groundwater arsenic pollution seem to be of natural origin and caused by reductive dissolution of arsenic-bearing iron phases buried in aquifers. The population at risk of chronic arsenic poisoning is estimated to be 10 million in the Red River delta and 0.5-1 million in the Mekong delta. A subset of hair samples collected in Vietnam and Cambodia from residents drinking groundwater with arsenic levels > 50 μg/L have a significantly higher arsenic content than control groups (< 50 μg/L). Few cases of arsenic related health problems are recognized in the study areas compared to Bangladesh and West Bengal. This difference probably relates to arsenic contaminated tube-well water only being used substantially over the past 7 to 10 years in Vietnam and Cambodia. Because symptoms of chronic arsenic poisoning usually take more than 10 years to develop, the number of future arsenic related ailments in Cambodia and Vietnam is likely to increase. Early mitigation measures should be a high priority

Conflict resolution among Niger delta communities: A historical ...

African Journals Online (AJOL)

Conflict related issues have assumed endemic proportion in the Niger Delta. A proper assessment of the critical factors in motion must take cognizance of their historical underpinnings. Peaceful co-existence, the hallmark of conflict resolution, can be feasible in the Niger Delta, through sustainable dialogue. These, among

Radioimmunoanalysis of delta-9-THC in blood by means of an 125I tracer

International Nuclear Information System (INIS)

Owens, S.M.; McBay, A.J.; Reisner, H.M.

1982-01-01

A radioimmunoassay for delta-9-THC in plasma, whole blood, or hemolyzed blood specimens has been presented. Samples and standards were diluted with methanol and centrifuged. An aliquot of the supernatant fluid was incubated with RIA buffer, 125 I-labeled delta-8-THC and rabbit anti-THC serum. Solid phase goat anti-rabbit immunoglobulins were added to separate bound from free THC. After centrifugation the supernatant fluid was aspirated and the radioactivity of the precipitate was counted in a gamma counter. The concentration of THC was calculated from a standard curve using the logit-log transformation of the average counts of duplicate tubes. The assay had several advantages. Methanol dilution gave better results than direct analysis. The 125 I-labeled THC had high specific activity and could be counted in a gamma counter. The immunological separation of antibody-bound THC from free THC was better than separation techniques using ammonium sulfate and activated charcoal. THC was determined in 0.1 ml of sample with a sensitivity of 1.5 ng/ml in plasma and 3.0 ng/ml in hemolyzed blood

Environmental Risk Profiling of the Volta Delta, Ghana

Science.gov (United States)

Nyarko, B. K.; Appeaning-Addo, K.; Amisigo, B.

2017-12-01

Volta Delta communities find it difficult to absorb or bear risk at different levels, because of the physical and economic impacts of environmental hazards. In this regards various agencies and organizations have in recent years launched initiatives to measure and identify risk areas with a set of indicators and indices. The theory underpinning this study is concepts of Modern Portfolio Theory (MPT). The Cox proportional hazards regression model will be used as the model for the risk profile. Finding the optimal level of environmental risk for activities in the Volta Delta considering the risk required, risk capacity and risk tolerance. Using data from different sources, an environmental risk profile was developed for the Volta Delta. The result indicates that risks are distributed across the Delta. However, areas that have government interventions, such as sea defense system and irrigation facilities have less threat. In addition wealthy areas do effectively reduce the threat of any form of disaster.

Seasonal Variation of Eutrophication in Some Lakes of Danube Delta Biosphere Reserve.

Science.gov (United States)

Török, Liliana; Török, Zsolt; Carstea, Elfrida M; Savastru, Dan

2017-01-01

  To understand the trophic state of lakes, this study aims to determine the dynamics of phytoplankton assemblages and the main factors that influence their seasonal variation. Sampling campaigns were carried out in three lakes from the Danube Delta Biosphere Reserve. Spectral analysis of specific phytoplankton pigments was applied as a diagnostic marker to establish the distribution and composition of phytoplankton taxonomic groups. Fluorescence spectroscopy was used to quantify changes in dissolved organic matter (DOM). The relative contribution of the main phytoplankton groups to the total phytoplankton biomass and the trend of development during succession of the seasons showed that cyanobacteria could raise potential ecological or human health problems. Moreover, fluorescence spectroscopy revealed that Cryptophyta and cyanobacteria were the main contributors to the protein-like components of DOM. It was concluded that fluorescence could be used to provide a qualitative evaluation of the eutrophication degree in Danube Delta lakes.

Biomass co-firing for Delta Electricity

International Nuclear Information System (INIS)

Anon

2014-01-01

Electricity generator Delta Electricity has implemented a biomass co-firing program at its Vales Point power station on the Central Coast to reduce its reliance on coal and emissions of CO 2 . The program comprises two parts: direct co-firing with coal of up to 5% biomass; and development of Continuous Biomass Converter (CBC) technology with the Crucible Group to remove technology constraints and enable much higher rates of biomass co-firing. It is talking industrial scale tests. Delta increased biomass co-firing in 2013/14 to 32,000 tonnes, up from just 3,000 tonnes the previous year, and conducted biochar co-firing trials at a rate equivalent to 400,000 tonnes per annum to demonstrate the potential of CBC technology. It reduced CO 2 emissions in 2013/14 by more than 32,000 tonnes. 'Legislation and regulations define biomass as renewable,' said Delta Electricity sustainability manager Justin Flood. 'By preferring biomass over coal, the carbon in the coal is not burnt and remains locked up.' One biomass source is wood waste that would normally go to landfill, but the primary driver of Delta's recent increase in co-firing is sawmill residues. 'Previously there was a higher value market for the residues for paper pulp. However, when that market evaporated the timber industry was left with a sizable problem in terms of what to do with its residues and the loss of revenue,' said Flood. The way greenhouse gas accounting is conducted in Australia, with carbon emissions based on site activities, makes it difficult to undertake a life cycle assessment of the program. 'However, some of the international studies looking at this issue have concluded that the net carbon emissions of the biomass system are significantly lower than the coal system because of the uptake of carbon during biomass growth,' said Flood. Delta identified two challenges, sourcing the feedstock and that biomass conversion to electricity is slightly less

Influence of habitat heterogeneity on anuran diversity in Restinga landscapes of the Parnaíba River delta, northeastern Brazil.

Science.gov (United States)

Araújo, Kássio C; Guzzi, Anderson; Ávila, Robson W

2018-01-01

Anurans have close associations with environmental conditions and therefore represent an interesting vertebrate group for examining how resource availability and environmental variables influence species diversity. Associations between habitat heterogeneity and anuran species diversity were tested in the Restinga landscapes of the Parnaíba River delta in northeastern Brazil. Twenty-one anuran species were sampled in the rainy season during monthly excursions (December 2015 to June 2016) into areas of Restinga on two islands in the Parnaíba River delta. The fourth highest anuran diversity was found in this type of environment in Brazil and is the third in northeastern Brazil. Microenvironments, characterized by a combination of vernal pools with different vegetational and physical structures, better explained anuran species composition in the Parnaíba River delta.

VTVH-MCD study of the Delta nifB Delta nifZ MoFe protein from Azotobacter vinelandii.

Science.gov (United States)

Cotton, Marcia S; Rupnik, Kresimir; Broach, Robyn B; Hu, Yilin; Fay, Aaron W; Ribbe, Markus W; Hales, Brian J

2009-04-08

NifZ is a member of a series of proteins associated with the maturation of the nitrogenase MoFe protein. An MCD spectroscopic study was undertaken on the Delta nifB Delta nifZ MoFe protein generated in the absence of both NifZ and NifB (deletion of NifB generates an apo-MoFe protein lacking the FeMo cofactor). Results presented here show that, in the absence of NifZ, only one of the two P-clusters of the MoFe protein is matured to the ultimate [8Fe-7S] structure. The other P-cluster site in the protein contains a [4Fe-4S] cluster pair, representing a P-cluster precursor that is electronically identical to the analogous clusters observed in the Delta nifH MoFe protein. These results suggest that the MoFe protein is synthesized in a stepwise fashion where NifZ is specifically required for the formation of the second P-cluster.

78 FR 45592 - DeltaPoint Capital IV, LP;

Science.gov (United States)

2013-07-29

..., Suite 160, Pittsford, NY 14534. The financing was contemplated for working capital. The financing is... SMALL BUSINESS ADMINISTRATION [License No. 02/02-0662] DeltaPoint Capital IV, LP; Notice Seeking... given that DeltaPoint Capital IV, L.P., 45 East Avenue, 6th Floor, Rochester, NY 14604, Federal...

Towards a Comprehensive Framework for Adaptive Delta Management

NARCIS (Netherlands)

Marchand, M.; Ludwig, F.

2014-01-01

Deltas are dynamic landforms at the boundary of land and sea, involving intricate mazes of rivers and small waterways, wetlands, estuaries and coastal barrier islands. They are home to over half a billion people. Deltas are also home to rich ecosystems, such as mangroves and marshes. They are

Assessing Niger-Delta Wetland Resources: A Case-Study of Mangrove Ecosystem

Science.gov (United States)

Anwan, R. H.; Ndimele, P. E.; Whenu, O. O.; Anetekhai, M. A.; Essien-Ibok, M. A.; Erondu, E. S.

2016-02-01

The Niger Delta is located in the Atlantic coast of Southern Nigeria and is the world's second largest delta with a coastline of about 450km. The Niger Delta region occupies a surface area of about 112,110km2, representing about 12% of Nigeria's total surface area. The Delta's environment can be broken down into four ecological zones: coastal barrier islands, mangrove swamp forests, freshwater swamps, and lowland rainforests. The mangrove swamps of Niger Delta, which is the largest delta in Africa constitute the dominant wetland ecosystem in the Niger Delta region and covers an area of about 1,900km2. Mangroves constitute important nurseries for fishes, crustaceans, sponges, algae and other invertebrates, and also acts as a sink, retaining pollutants from contaminated tidal water. The Niger Delta mangrove together with the creeks and rivers are a major source of food and livelihood for about 30 million people, which represents more than 17% of Nigeria's population. Other ecosystem services provided by this unique environment are flood control, ground water re-fill, reservoir of biodiversity, fuel wood, cultural values etc. This ecosystem also plays important role in climate change mitigation because of its high blue carbon sequestration potential. This is particularly important because of continuous gas flaring in Niger Delta from petroleum operations, which releases carbon dioxide among other gases into the atmosphere. This wetland is potentially a good site for ecotourism and also qualifies to be a world heritage site and Ramsar site if proper steps are taken. The benefits derivable from this fragile ecosystem are under severe threat by anthropogenic stressors. These include the installation of pipelines and seismic exploration by oil companies, crude oil pollution, deforestation, urbanization etc. This paper discusses the extent of depletion and loss of mangrove ecosystem in the Niger Delta region and the value of its goods and services.

A comparative study of multilayer perceptron neural networks for the identification of rhubarb samples.

Science.gov (United States)

Zhang, Zhuoyong; Wang, Yamin; Fan, Guoqiang; Harrington, Peter de B

2007-01-01

Artificial neural networks have gained much attention in recent years as fast and flexible methods for quality control in traditional medicine. Near-infrared (NIR) spectroscopy has become an accepted method for the qualitative and quantitative analyses of traditional Chinese medicine since it is simple, rapid, and non-destructive. The present paper describes a method by which to discriminate official and unofficial rhubarb samples using three layer perceptron neural networks applied to NIR data. Multilayer perceptron neural networks were trained with back propagation, delta-bar-delta and quick propagation algorithms. Results obtained using these methods were all satisfactory, but the best outcomes were obtained with the delta-bar-delta algorithm.

Conservative Delta Hedging

Science.gov (United States)

1997-09-01

an exact method for converting such intervals into arbitrage based prices of financial derivatives or industrial or contractual options. We call this...procedure conservative delta hedging . As existing procedures are of an ad hoc nature, the proposed approach will permit an institution’s man agement a greater oversight of its exposure to risk.

Sedimentation patterns in floodplains of the Mekong Delta - Vietnam

Science.gov (United States)

Van Manh, Nguyen; Merz, Bruno; Viet Dung, Nguyen; Apel, Heiko

2013-04-01

Quantification of floodplain sedimentation during the flood season in the Mekong Delta (MD) plays a very important role in the assessment of flood deposits for a sustainable agro-economic development. Recent studies on floodplain sedimentation in the region are restricted to small pilot sites because of the large extend of the Delta, and the complex channel. This research aims at a quantification of the sediment deposition in floodplains of the whole Mekong Delta, and to access the impacts of the upstream basin development on the sedimentation in the Delta quantitatively. To achieve this, a suspended sediment transport model is developed based on the quasi-2D hydrodynamic model of the whole Mekong Delta developed by Dung et al. (2011). The model is calibrated and validated using observed data derived from several sediment measurement campaigns in channel networks and floodplains. Measured sediment data and hydrodynamic model quantify the spatio-temporal variability of sediment depositions in different spatial units: individual dyke compartments, and the sub-regions Plain of Reeds, Long Xuyen Quadrangle and the area between Tien River and Hau River. It is shown that the distribution of sediment deposition over the delta is highly depended on the flood magnitude, that in turn drives the operation policy of flood control systems in floodplains of the Mekong Delta. Thus, the sedimentation distribution is influenced by the protection level of the dyke systems in place and the distance to the Tien River and Hau River, the main branches of the Mekong in the Delta. This corroborates the main findings derived from data analysis obtained from a small scale test site by Hung et al, (2011, 2012a). Moreover, the results obtained here underlines the importance of the main channels for the sediment transport into the floodplains, and the deposition rate in floodplains is strongly driven by the intake locations and the distance from these to the main channels as well.

Flipped SU(5) predicts {delta}T/T

Energy Technology Data Exchange (ETDEWEB)

Kyae, Bumseok [School of Physics, Korea Institute for Advanced Study, 207-43, Cheongnyangni-Dong, Dongdaemun-Gu, Seoul 130-722 (Korea, Republic of)]. E-mail: bkyae@kias.re.kr; Shafi, Qaisar [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)]. E-mail: shafi@bartol.udel.edu

2006-04-20

We discuss hybrid inflation in supersymmetric flipped SU(5) model such that the cosmic microwave anisotropy {delta}T/T is essentially proportional to (M/M{sub P}){sup 2}, where M denotes the symmetry breaking scale and M{sub P} (=2.4x10{sup 18} GeV) is the reduced Planck mass. The magnitude of M determined from {delta}T/T measurements can be consistent with the value inferred from the evolution of SU(3) and SU(2) gauge couplings. In other words, one could state that flipped SU(5) predicts (more precisely 'postdicts') {delta}T/T. The scalar spectral index n{sub s}=0.993+/-0.007, the scalar to tensor ratio satisfies r-bar 10{sup -6}, while dn{sub s}/dlnk-bar 4x10{sup -4}.

Thermostatted delta f

International Nuclear Information System (INIS)

Krommes, J.A.

2000-01-01

The delta f simulation method is revisited. Statistical coarse-graining is used to rigorously derive the equation for the fluctuation delta f in the particle distribution. It is argued that completely collisionless simulation is incompatible with the achievement of true statistically steady states with nonzero turbulent fluxes because the variance of the particle weights w grows with time. To ensure such steady states, it is shown that for dynamically collisionless situations a generalized thermostat or W-stat may be used in lieu of a full collision operator to absorb the flow of entropy to unresolved fine scales in velocity space. The simplest W-stat can be implemented as a self-consistently determined, time-dependent damping applied to w. A precise kinematic analogy to thermostatted nonequilibrium molecular dynamics (NEMD) is pointed out, and the justification of W-stats for simulations of turbulence is discussed. An extrapolation procedure is proposed such that the long-time, steady-state, collisionless flux can be deduced from several short W-statted runs with large effective collisionality, and a numerical demonstration is given

Lava delta deformation as a proxy for submarine slope instability

Science.gov (United States)

Di Traglia, Federico; Nolesini, Teresa; Solari, Lorenzo; Ciampalini, Andrea; Frodella, William; Steri, Damiano; Allotta, Benedetto; Rindi, Andrea; Marini, Lorenzo; Monni, Niccolò; Galardi, Emanuele; Casagli, Nicola

2018-04-01

The instability of lava deltas is a recurrent phenomenon affecting volcanic islands, which can potentially cause secondary events such as littoral explosions (due to interactions between hot lava and seawater) and tsunamis. It has been shown that Interferometric Synthetic Aperture Radar (InSAR) is a powerful technique to forecast the collapse of newly emplaced lava deltas. This work goes further, demonstrating that the monitoring of lava deltas is a successful strategy by which to observe the long-term deformation of subaerial-submarine landslide systems on unstable volcanic flanks. In this paper, displacement measurements derived from Synthetic Aperture Radar (SAR) imagery were used to detect lava delta instability at Stromboli volcano (Italy). Recent flank eruptions (2002-2003, 2007 and 2014) affected the Sciara del Fuoco (SdF) depression, created a "stacked" lava delta, which overlies a pre-existing scar produced by a submarine-subaerial tsunamigenic landslide that occurred on 30 December 2002. Space-borne X-band COSMO-SkyMED (CSK) and C-band SENTINEL-1A (SNT) SAR data collected between February 2010 and October 2016 were processed using the SqueeSAR algorithm. The obtained ground displacement maps revealed the differential ground motion of the lava delta in both CSK and SNT datasets, identifying a stable area (characterized by less than 2 mm/y in both datasets) within the northern sector of the SdF and an unstable area (characterized by velocity fields on the order of 30 mm/y and 160 mm/y in the CSK and SNT datasets, respectively) in the central sector of the SdF. The slope stability of the offshore part of the SdF, as reconstructed based on a recently performed multibeam bathymetric survey, was evaluated using a 3D Limit Equilibrium Method (LEM). In all the simulations, Factor of Safety (F) values between 0.9 and 1.1 always characterized the submarine slope between the coastline and -250 m a.s.l. The critical surfaces for all the search volumes corresponded to

Parametrization of the. delta. residue function. [Complex functions

Energy Technology Data Exchange (ETDEWEB)

Vasan, S S [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics

1976-04-19

The complex residues at the ..delta..(1236) and ..delta..(1950) poles in the relevant partial-wave amplitudes provide information on the behaviour of the ..delta.. Regge residue function in the resonance region u>0. Attempts to incorporate this information in parametrizations of the residue by functions that are real on the real u-axis result in residues which have unsatisfactory behaviour in the region u<1GeV/sup 2/. The choice of complex functions for the trajectory and residue removes this undesirable feature and provides a better representation of the residue in the resonance region, suggesting that complex parametrizations would be better suited to Regge analyses of near-backward scattering.

Central Delta languages: An overview | Kari | Stellenbosch Papers ...

African Journals Online (AJOL)

This paper presents an overview of the phonology, morphology and syntax of Central Delta languages. It also provides information on the geo-linguistic, demographic and sociolinguistic situation of these languages. It notes that Central Delta languages have a 20-vowel system, which divides into two sets of 10 vowels ...

Topological Mappings via B&delta;g-Closed Sets

OpenAIRE

Maruthamuthu, Raja; Narayanasamy, Seenivasagan; Otchanathevar, Ravi

2018-01-01

In this paper we introduce a new class of functions called  B&delta;g-continuous functions. We obtain several characterizations and some their properties. Also we investigate its relationship with other types of functions. Further we introduce and study a new class of functions namely B&delta;g-irresolute.

Sand transport, shear stress, and the building of a delta

Science.gov (United States)

Wagner, W.; Miller, K. L.; Hiatt, M. R.; Mohrig, D. C.

2017-12-01

River deltas distribute sediment to the coastal sea through a complex branching network of channels; however, the routing and storage of this sediment in and through the delta is poorly understood. We present results from field studies of the sediment and water transport through the branching Wax Lake Delta on the coast of Louisiana. Two channels studied, Main Pass and East Pass, maintain a near-equal total partitioning of flow and sediment. However, East Pass is narrower and has higher river velocities, lower tidal velocity fluctuations, less alluvial bed cover, and more sediment flux per unit width than Main Pass. We connect these differences to small differences in the geometry of the two channels and feedbacks between these differences. We link trends in measured sediment deposits to both measured and modeled shear velocities in Wax Lake Delta's channels and open water `islands' to understand how hydrologic processes shaped the sedimentary architecture of the delta. These connections define the sediment transport and deposition regimes in the WLD. We extend the results herein to suggest that the relationships between the available sediment and shear stress determines the basic planform of the Wax Lake Delta and cross-sectional geometries of its channels.

Molecular characterization of three 3-ketosteroid-Delta(1)-dehydrogenase isoenzynnes of Rhodococcus ruber strain Chol-4

NARCIS (Netherlands)

Fernandez de las Heras, Laura; van der Geize, Robert; Drzyzga, Oliver; Perera, Julian; Navarro Llorens, Juana Maria

2012-01-01

Rhodococcus ruber strain Chol-4 isolated from a sewage sludge sample is able to grow on minimal medium supplemented with steroids, showing a broad catabolic capacity. This paper reports the characterization of three different 3-ketosteroid-Delta(1)-dehydrogenases (KstDs) in the genome of R. ruber

Signal-to-noise ratio estimation in digital computer simulation of lowpass and bandpass systems with applications to analog and digital communications, volume 3

Science.gov (United States)

Tranter, W. H.; Turner, M. D.

1977-01-01

Techniques are developed to estimate power gain, delay, signal-to-noise ratio, and mean square error in digital computer simulations of lowpass and bandpass systems. The techniques are applied to analog and digital communications. The signal-to-noise ratio estimates are shown to be maximum likelihood estimates in additive white Gaussian noise. The methods are seen to be especially useful for digital communication systems where the mapping from the signal-to-noise ratio to the error probability can be obtained. Simulation results show the techniques developed to be accurate and quite versatile in evaluating the performance of many systems through digital computer simulation.

A Novel Sigma-Delta Modulator with Fractional-Order Digital Loop Integrator

Directory of Open Access Journals (Sweden)

Chi Xu

2017-01-01

Full Text Available This paper proposes using a fractional-order digital loop integrator to improve the robust stability of Sigma-Delta modulator, thus extending the integer-order Sigma-Delta modulator to a non-integer-order (fractional-order one in the Sigma-Delta ADC design field. The proposed fractional-order Sigma-Delta modulator has reasonable noise characteristics, dynamic range, and bandwidth; moreover the signal-to-noise ratio (SNR is improved remarkably. In particular, a 2nd-order digital loop integrator and a digital PIλDμ controller are combined to work as the fractional-order digital loop integrator, which is realized using FPGA; this will reduce the ASIC analog circuit layout design and chip testing difficulties. The parameters of the proposed fractional-order Sigma-Delta modulator are tuned by using swarm intelligent algorithm, which offers opportunity to simplify the process of tuning parameters and further improve the noise performance. Simulation results are given and they demonstrate the efficiency of the proposed fractional-order Sigma-Delta modulator.

Challenges and Approaches in River Delta Planning - Annexes to report on training workshop

NARCIS (Netherlands)

Wosten, J.H.M.; Douven, W.; Long Phi, H.; Fida Abdullah Khan, M.

2012-01-01

Programme, participants and all powerpoint presentations of the Delta Alliance Training Workshop: Challenges and approaches in river delta planning, sharing experiences from SE Asian Deltas and the Rhine-Meuse Delta. 22-26 October 2012, WACC, Vietnam National University, Ho Chi Minh City, Vietnam

Cerebral correlates of delta waves during non-REM sleep revisited.

Science.gov (United States)

Dang-Vu, Thien Thanh; Desseilles, Martin; Laureys, Steven; Degueldre, Christian; Perrin, Fabien; Phillips, Christophe; Maquet, Pierre; Peigneux, Philippe

2005-10-15

We aimed at characterizing the neural correlates of delta activity during Non Rapid Eye Movement (NREM) sleep in non-sleep-deprived normal young adults, based on the statistical analysis of a positron emission tomography (PET) sleep data set. One hundred fifteen PET scans were obtained using H(2)(15)O under continuous polygraphic monitoring during stages 2-4 of NREM sleep. Correlations between regional cerebral blood flow (rCBF) and delta power (1.5-4 Hz) spectral density were analyzed using statistical parametric mapping (SPM2). Delta power values obtained at central scalp locations negatively correlated during NREM sleep with rCBF in the ventromedial prefrontal cortex, the basal forebrain, the striatum, the anterior insula, and the precuneus. These regions embrace the set of brain areas in which rCBF decreases during slow wave sleep (SWS) as compared to Rapid Eye Movement (REM) sleep and wakefulness (Maquet, P., Degueldre, C., Delfiore, G., Aerts, J., Peters, J.M., Luxen, A., Franck, G., 1997. Functional neuroanatomy of human slow wave sleep. J. Neurosci. 17, 2807-S2812), supporting the notion that delta activity is a valuable prominent feature of NREM sleep. A strong association was observed between rCBF in the ventromedial prefrontal regions and delta power, in agreement with electrophysiological studies. In contrast to the results of a previous PET study investigating the brain correlates of delta activity (Hofle, N., Paus, T., Reutens, D., Fiset, P., Gotman, J., Evans, A.C., Jones, B.E., 1997. Regional cerebral blood flow changes as a function of delta and spindle activity during slow wave sleep in humans. J. Neurosci. 17, 4800-4808), in which waking scans were mixed with NREM sleep scans, no correlation was found with thalamus activity. This latter result stresses the importance of an extra-thalamic delta rhythm among the synchronous NREM sleep oscillations. Consequently, this rCBF distribution might preferentially reflect a particular modulation of the

Adaptive delta management: a comparison between the Netherlands and Bangladesh Delta Program

NARCIS (Netherlands)

Zevenbergen, Chris; Khan, Shah Alam; Alphen, van Jos; Terwisscha van Scheltinga, Catharien; Veerbeek, William

2018-01-01

In the Netherlands, the central government, water authorities, provinces and municipalities are working together on a new Delta Program on Flood Risk Management and Fresh Water Supply (DP). Its primary goal is to protect the Netherlands against floods and ensure the availability of fresh water, now

Cohesive Sedimentary Processes on River-Dominated Deltas: New Perspectives from the Mississippi River Delta Front, Gulf of Mexico

Science.gov (United States)

Bentley, S. J.; Keller, G. P.; Obelcz, J.; Maloney, J. M.; Xu, K.; Georgiou, I. Y.; Miner, M. D.

2016-12-01

On river deltas dominated by proximal sediment accumulation (Mississippi, Huang He, others), the delta front region is commonly dominated by rapid accumulation of cohesive fluvial sediments, and mass-wasting processes that remobilize recently deposited sediments. Mass transport is preconditioned in sediments by high water content, biogenic gas production, over steepening, and is commonly triggered by strong wave loading and other processes. This understanding is based on extensive field studies in the 1970's and 80's. Recent studies of the Mississippi River Delta Front are yielding new perspectives on these processes, in a time of anthropogenically reduced sediment loads, rising sea level, and catastrophic deltaic land loss. We have synthesized many industry data sets collected since ca. 1980, and conducted new pilot field and modeling studies of sedimentary and morphodynamic processes. These efforts have yielded several key findings that diverge from historical understanding of this dynamic setting. First, delta distributary mouths have ceased seaward progradation, ending patterns that have been documented since the 18th century. Second, despite reduced sediment supply, offshore mass transport continues, yielding vertical displacements at rates of 1 m/y. This displacement is apparently forced by wave loading from storm events of near-annual return period, rather than major hurricanes that have been the focus of most previous studies. Third, core analysis indicates that this vertical displacement is occurring along failure planes >3 m in the seabed, rather than in more recently deposited sediments closer to the sediment-water interface. These seabed morphodynamics have the potential to destabilize both nearshore navigation infrastructure, and seabed hydrocarbon infrastructure offshore. As well, these findings raise more questions regarding the future seabed evolution offshore of major river deltas, in response to anthropogenic and climatic forcing.

Laser ablation-combustion-GC-IRMS--a new method for online analysis of intra-annual variation of delta13C in tree rings.

Science.gov (United States)

Schulze, Brigit; Wirth, Christian; Linke, Petra; Brand, Willi A; Kuhlmann, Iris; Horna, Viviana; Schulze, Ernst-Detlef

2004-11-01

We present a new, rapid method for high-resolution online determination of delta13C in tree rings, combining laser ablation (LA), combustion (C), gas chromatography (GC) and isotope ratio mass spectrometry (IRMS) (LA-C-GC-IRMS). Sample material was extracted every 6 min with a UV-laser from a tree core, leaving 40-microm-wide holes. Ablated wood dust was combusted to CO2 at 700 degrees C, separated from other gases on a GC column and injected into an isotope ratio mass spectrometer after removal of water vapor. The measurements were calibrated against an internal and an external standard. The tree core remained intact and could be used for subsequent dendrochronological and dendrochemical analyses. Cores from two Scots pine trees (Pinus sylvestris spp. sibirica Lebed.) from central Siberia were sampled. Inter- and intra-annual patterns of delta13C in whole-wood and lignin-extracted cores were indistinguishable apart from a constant offset, suggesting that lignin extraction is unnecessary for our method. Comparison with the conventional method (microtome slicing, elemental analysis and IRMS) indicated high accuracy of the LA-C-GC-IRMS measurements. Patterns of delta13C along three parallel ablation lines on the same core showed high congruence. A conservative estimate of the precision was +/- 0.24 per thousand. Isotopic patterns of the two Scots pine trees were broadly similar, indicating a signal related to the forest stand's climate history. The maximum variation in delta13C over 22 years was about 5 per thousand, ranging from -27 to -22.3 per thousand. The most obvious pattern was a sharp decline in delta13C during latewood formation and a rapid increase with spring early growth. We conclude that the LA-C-GC-IRMS method will be useful in elucidating short-term climate effects on the delta13C signal in tree rings.

Grain-size sorting in grainflows at the lee side of deltas

NARCIS (Netherlands)

Kleinhans, M.G.

2005-01-01

The sorting of sediment mixtures at the lee slope of deltas (at the angle of repose) is studied with experiments in a narrow, deep flume with subaqueous Gilbert-type deltas using varied flow conditions and different sediment mixtures. Sediment deposition and sorting on the lee slope of the delta

Governance of ‘long term delta planning’ in Bangladesh, Vietnam and the Netherlands

NARCIS (Netherlands)

Staveren, van M.F.

2014-01-01

The Deltas in Times of Climate Change Conference II, taking place in September 2014, Rotterdam, presented a suitable occasion to discuss both delta challenges and interesting approaches to how ‘delta dynamics’ are being dealt with worldwide.1 Delta dynamics include here both environmental (including

Structure of the [delta]-opioid receptor bound to naltrindole

Energy Technology Data Exchange (ETDEWEB)

Granier, Sébastien; Manglik, Aashish; Kruse, Andrew C.; Kobilka, Tong Sun; Thian, Foon Sun; Weis, William I.; Kobilka, Brian K. (Stanford-MED)

2012-07-11

The opioid receptor family comprises three members, the {mu}-, {delta}- and {kappa}-opioid receptors, which respond to classical opioid alkaloids such as morphine and heroin as well as to endogenous peptide ligands like endorphins. They belong to the G-protein-coupled receptor (GPCR) superfamily, and are excellent therapeutic targets for pain control. The {delta}-opioid receptor ({delta}-OR) has a role in analgesia, as well as in other neurological functions that remain poorly understood. The structures of the {mu}-OR and {kappa}-OR have recently been solved. Here we report the crystal structure of the mouse {delta}-OR, bound to the subtype-selective antagonist naltrindole. Together with the structures of the {mu}-OR and {kappa}-OR, the {delta}-OR structure provides insights into conserved elements of opioid ligand recognition while also revealing structural features associated with ligand-subtype selectivity. The binding pocket of opioid receptors can be divided into two distinct regions. Whereas the lower part of this pocket is highly conserved among opioid receptors, the upper part contains divergent residues that confer subtype selectivity. This provides a structural explanation and validation for the 'message-address' model of opioid receptor pharmacology, in which distinct 'message' (efficacy) and 'address' (selectivity) determinants are contained within a single ligand. Comparison of the address region of the {delta}-OR with other GPCRs reveals that this structural organization may be a more general phenomenon, extending to other GPCR families as well.

Stable isotope ratio measurements on highly enriched water samples by means of laser spectrometry

NARCIS (Netherlands)

van Trigt, R; Kerstel, E.R.T.; Visser, GH; Meijer, H.A.J.

2001-01-01

We demonstrate the feasibility of using laser spectrometry (LS) to analyze isotopically highly enriched water samples (i.e., delta H-2 less than or equal to 15000 parts per thousand, delta O-18 less than or equal to 1200 parts per thousand), as often used in the biomedical doubly labeled water (DLW)

Precipitation of {gamma}' phase in {delta}-precipitated Alloy 718 during deformation at elevated temperatures

Energy Technology Data Exchange (ETDEWEB)

Nalawade, S.A. [Structural Metallurgy Section, Mechanical Metallurgy Section, Bhabha Atomic Research Centre, Mumbai 400085 (India); Sundararaman, M., E-mail: msraman@barc.gov.in [Structural Metallurgy Section, Mechanical Metallurgy Section, Bhabha Atomic Research Centre, Mumbai 400085 (India); Singh, J.B.; Verma, A.; Kishore, R. [Structural Metallurgy Section, Mechanical Metallurgy Section, Bhabha Atomic Research Centre, Mumbai 400085 (India)

2010-05-15

Alloy 718 samples aged to precipitate only {delta} particles (with maximum volume fraction) when tensile deformed to fracture at elevated temperatures revealed precipitation of {gamma}' and {gamma}'' phases. The {gamma}' precipitation was found to precede the {gamma}'' phase precipitation unlike in the case of specimens subjected to standard ageing treatment where both the {gamma}' and the {gamma}'' phases precipitate simultaneously. This sequence is explained on the basis of the relative concentration of Al, Ti and Nb in the matrix of {delta} precipitated Alloy 718 microstructure. The precipitation sequence was consistent with the Cozar and Pineau's model that predicts such sequences on the basis of (Al + Ti) to Nb atom ratios.

One-step synthesis of delta-MnO2 nanoparticles using ascorbic acid and their scavenging properties to Pb(II), Zn(II) and methylene blue

NARCIS (Netherlands)

Wang, M.X.; Pang, P.; Koopal, L.K.; Qiu, G.H.; Wang, Y.; Liu, F.

2014-01-01

To obtain delta-MnO2 particles with a large specific surface area, MnO2 was synthesized in an ice-water bath using ascorbic acid (AA) to reduce KMnO4. At pH 3 and 5 and KMnO4/AA molar ratios of 8/1 and 10/1, nanoparticles of delta-MnO2 were produced. The specific surface areas (SSAs) of the samples

T-cell receptor gamma delta bearing cells in normal human skin

NARCIS (Netherlands)

Bos, J. D.; Teunissen, M. B.; Cairo, I.; Krieg, S. R.; Kapsenberg, M. L.; Das, P. K.; Borst, J.

1990-01-01

T-cell antigen receptors (TCR) are divided into common alpha beta and less common gamma delta types. In the murine skin, TCR gamma delta+ cells have been reported to form the great majority of epidermal T lymphocytes. We have examined the relative contribution of TCR alpha beta+ and TCR gamma delta+

Hole states in diamond p-delta-doped field effect transistors

International Nuclear Information System (INIS)

Martinez-Orozco, J C; Rodriguez-Vargas, I; Mora-Ramos, M E

2009-01-01

The p-delta-doping in diamond allows to create high density two-dimensional hole gases. This technique has already been applied in the design and fabrication of diamond-based field effect transistors. Consequently, the knowledge of the electronic structure is of significant importance to understand the transport properties of diamond p-delta-doped systems. In this work the hole subbands of diamond p-type delta-doped quantum wells are studied within the framework of a local-density Thomas-Fermi-based approach for the band bending profile. The calculation incorporates an independent three-hole-band scheme and considers the effects of the contact potential, the delta-channel to contact distance, and the ionized impurity density.

Hole states in diamond p-delta-doped field effect transistors

Energy Technology Data Exchange (ETDEWEB)

Martinez-Orozco, J C; Rodriguez-Vargas, I [Unidad Academica de Fisica, Universidad Autonoma de Zacatecas, Calzada Solidaridad Esquina con Paseo la Bufa S/N, CP 98060 Zacatecas, ZAC. (Mexico); Mora-Ramos, M E, E-mail: jcmover@correo.unam.m [Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, CP 62209 Cuernavaca, MOR. (Mexico)

2009-05-01

The p-delta-doping in diamond allows to create high density two-dimensional hole gases. This technique has already been applied in the design and fabrication of diamond-based field effect transistors. Consequently, the knowledge of the electronic structure is of significant importance to understand the transport properties of diamond p-delta-doped systems. In this work the hole subbands of diamond p-type delta-doped quantum wells are studied within the framework of a local-density Thomas-Fermi-based approach for the band bending profile. The calculation incorporates an independent three-hole-band scheme and considers the effects of the contact potential, the delta-channel to contact distance, and the ionized impurity density.

Wide Bandpass and Narrow Bandstop Microstrip Filters based on Hilbert fractal geometry: design and simulation results.

Directory of Open Access Journals (Sweden)

Yaqeen S Mezaal

Full Text Available This paper presents new Wide Bandpass Filter (WBPF and Narrow Bandstop Filter (NBSF incorporating two microstrip resonators, each resonator is based on 2nd iteration of Hilbert fractal geometry. The type of filter as pass or reject band has been adjusted by coupling gap parameter (d between Hilbert resonators using a substrate with a dielectric constant of 10.8 and a thickness of 1.27 mm. Numerical simulation results as well as a parametric study of d parameter on filter type and frequency responses are presented and studied. WBPF has designed at resonant frequencies of 2 and 2.2 GHz with a bandwidth of 0.52 GHz, -28 dB return loss and -0.125 dB insertion loss while NBSF has designed for electrical specifications of 2.37 GHz center frequency, 20 MHz rejection bandwidth, -0.1873 dB return loss and 13.746 dB insertion loss. The proposed technique offers a new alternative to construct low-cost high-performance filter devices, suitable for a wide range of wireless communication systems.

Asymptotic Effectiveness of the Event-Based Sampling According to the Integral Criterion

Directory of Open Access Journals (Sweden)

Marek Miskowicz

2007-01-01

Full Text Available A rapid progress in intelligent sensing technology creates new interest in a development of analysis and design of non-conventional sampling schemes. The investigation of the event-based sampling according to the integral criterion is presented in this paper. The investigated sampling scheme is an extension of the pure linear send-on- delta/level-crossing algorithm utilized for reporting the state of objects monitored by intelligent sensors. The motivation of using the event-based integral sampling is outlined. The related works in adaptive sampling are summarized. The analytical closed-form formulas for the evaluation of the mean rate of event-based traffic, and the asymptotic integral sampling effectiveness, are derived. The simulation results verifying the analytical formulas are reported. The effectiveness of the integral sampling is compared with the related linear send-on-delta/level-crossing scheme. The calculation of the asymptotic effectiveness for common signals, which model the state evolution of dynamic systems in time, is exemplified.

Linking rapid erosion of the Mekong River delta to human activities.

Science.gov (United States)

Anthony, Edward J; Brunier, Guillaume; Besset, Manon; Goichot, Marc; Dussouillez, Philippe; Nguyen, Van Lap

2015-10-08

As international concern for the survival of deltas grows, the Mekong River delta, the world's third largest delta, densely populated, considered as Southeast Asia's most important food basket, and rich in biodiversity at the world scale, is also increasingly affected by human activities and exposed to subsidence and coastal erosion. Several dams have been constructed upstream of the delta and many more are now planned. We quantify from high-resolution SPOT 5 satellite images large-scale shoreline erosion and land loss between 2003 and 2012 that now affect over 50% of the once strongly advancing >600 km-long delta shoreline. Erosion, with no identified change in the river's discharge and in wave and wind conditions over this recent period, is consistent with: (1) a reported significant decrease in coastal surface suspended sediment from the Mekong that may be linked to dam retention of its sediment, (2) large-scale commercial sand mining in the river and delta channels, and (3) subsidence due to groundwater extraction. Shoreline erosion is already responsible for displacement of coastal populations. It is an additional hazard to the integrity of this Asian mega delta now considered particularly vulnerable to accelerated subsidence and sea-level rise, and will be exacerbated by future hydropower dams.

Plant delta 15N correlates with the transpiration efficiency of nitrogen acquisition in tropical trees.

Science.gov (United States)

Cernusak, Lucas A; Winter, Klaus; Turner, Benjamin L

2009-11-01

Based upon considerations of a theoretical model of (15)N/(14)N fractionation during steady-state nitrate uptake from soil, we hypothesized that, for plants grown in a common soil environment, whole-plant delta(15)N (deltaP) should vary as a function of the transpiration efficiency of nitrogen acquisition (F(N)/v) and the difference between deltaP and root delta(15)N (deltaP - deltaR). We tested these hypotheses with measurements of several tropical tree and liana species. Consistent with theoretical expectations, both F(N)/v and deltaP - deltaR were significant sources of variation in deltaP, and the relationship between deltaP and F(N)/v differed between non-N(2)-fixing and N(2)-fixing species. We interpret the correlation between deltaP and F(N)/v as resulting from variation in mineral nitrogen efflux-to-influx ratios across plasma membranes of root cells. These results provide a simple explanation of variation in delta(15)N of terrestrial plants and have implications for understanding nitrogen cycling in ecosystems.

KAJIAN PENCEMARAN LINGKUNGAN DI TAMBAK UDANG DELTA MAHAKAM

Directory of Open Access Journals (Sweden)

Salahuddin, Chafid Fandeli, dan Eko Sugiharto

2012-06-01

Full Text Available well-managed, it will contribute to the improvement of both regional and national economy. However, MahakamRiver gets liquid waste pollution that has significant impact on water quality and results in conflicts betweenthe local societies, especially the shrimp pond farmers and the fishermen and the oil and gas industrial company.This research uses descriptive-comparative analysis with ANOVA test to compare samples (water, soil/sediment,shrimp, and mangrove of the shrimp fishpond (many mangrove, moderate mangrove, few mangrove, and withoutany mangrove. The pollution load which is analyzed includes: cadmium content (Cd, lead (Pb, oil and grease (O& G, mercury (Hg, and arsenic (As. The significance level is 90% with error of 5% (0.05.The water of Mahakam Delta is still in the normality limit as seen from the maximum pollution load in the Decreeof the Minister of Living Environment No. 51 of 2004 on Ocean Water Standard seen from chemical, physical,and biological parameters. The presence of mangrove contributes positive value to the balance of the quality of thewaters and to the neutralizing of heavy metals contents of Mahakam Delta as shown in the average difference inthe Pb, Cd, O & G, As and Hg of the samples of water, soils/sediment, shrimp and mangrove which are drawnfrom the of shrimp pond with many mangrove, moderate mangrove, few mangrove and without any mangrove,which is significantly different (p < 0.05. Shrimp pond with many mangrove has less average levels of Pb, Cd, M& L, As and Hg compared with the pond with less and without mangrove. The shrimp pond with many mangrovescontributes significantly and positively to the prevention of the pollution of Pb, Cd, O and G, As and Hg at low level

Laboratory investigation on effects of flood intermittency on river delta dynamics

Science.gov (United States)

Miller, K. L.; Kim, W.

2015-12-01

In order to simplify the complex hydrological variability of flow conditions, experiments modeling delta evolution are often conducted using a representative "channel-forming" flood flow and then relate results to field settings using an intermittency factor, defined as the fraction of total time at flood conditions. Although this intermittency factor makes it easier to investigate how variables, such as relative base level and/or sediment supply, affect delta dynamics, little is known about how this generalization to a single flow condition affects delta processes. We conducted a set of laboratory experiments with periodic flow conditions to determine the effects of intermittent discharges on delta evolution. During the experiment, flood with a set water discharge and sediment supply, cycles between periods of normal flow where the water flux is halved and the sediment discharge is turned off. For each run, the magnitude of the flood is held constant, but the duration is assigned differently, thus varying the intermittency between 1 and 0.2. We find that as the intermittency factor decreases (duration of each flood period decreases), the delta topset has a larger, more elongated area with a shallower slope as a result of reworking on the delta topset during normal flow conditions. During periods of normal flow, the system adjusts towards a new equilibrium state that then in turn acts as the initial condition for the subsequent flood period. Furthermore, the natural delta avulsion cycle becomes obscured by the flood cycles as the flood duration becomes shorter than the autogenic behavior. These results suggest that the adjustment timescale for differing flow conditions is a factor in determining the overall shape of the delta and behavior of the fluviodeltaic channels. We conclude, periods of normal flow when topset sediment is reworked, may be just as important to delta dynamics as periods of flood when sediment is supplied to the system.

Plasticity of gamma delta T cells: impact on the anti-tumor response

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Virginie eLafont

2014-12-01

Full Text Available The tumor immune microenvironment contributes to tumor initiation, progression and response to therapy. Among the immune cell subsets that play a role in the tumor microenvironment, innate-like T cells that express T cell receptors composed of gamma and delta chains (gamma delta T cells are of particular interest. gamma delta T cells can contribute to the immune response against many tumor types (lymphoma, myeloma, melanoma, breast, colon, lung, ovary and prostate cancer directly through their cytotoxic activity and indirectly by stimulating or regulating the biological functions of other cell types required for the initiation and establishment of the anti-tumor immune response, such as dendritic cells and cytotoxic CD8+ T cells. However, the notion that tumor-infiltrating gamma delta T cells are a good prognostic marker in cancer was recently challenged by studies showing that the presence of these cells in the tumor microenvironment was associated with poor prognosis in both breast and colon cancer. These findings suggest that gamma delta T cells may also display pro-tumor activities. Indeed, breast tumor-infiltrating gamma deltaT cells could exert an immunosuppressive activity by negatively regulating DC maturation. Furthermore, recent studies demonstrated that signals from the microenvironment, particularly cytokines, can confer some plasticity to gamma delta T cells and promote their differentiation into gamma delta T cells with regulatory functions. This review focuses on the current knowledge on the functional plasticity of gamma delta T cells and its effect on their anti-tumor activities. It also discusses the putative mechanisms underlying gamma delta T cell expansion, differentiation and recruitment in the tumor microenvironment.

Oil and Security in Nigeria: The Niger Delta Crisis | Owolabi | Africa ...

African Journals Online (AJOL)

This paper examines oil and security in Nigeria, with special reference to the crisis-ravaged Niger Delta. Its focus on the Niger Delta and its festering crisis stems from that region's critical importance to Nigeria. As the nation's treasure base, the Niger Delta provides over 80 percent of government revenues, 95 percent of ...

Peroxisome proliferator-activated receptor delta activation leads to increased transintestinal cholesterol efflux

NARCIS (Netherlands)

Vrins, Carlos L. J.; van der Velde, Astrid E.; van den Oever, Karin; Levels, Johannes H. M.; Huet, Stephane; Elferink, Ronald P. J. Oude; Kuipers, Folkert; Groen, Albert K.

2009-01-01

Peroxisome proliferator-activated receptor delta (PPAR delta) is involved in regulation of energy homeostasis. Activation of PPAR delta markedly increases fecal neutral sterol secretion, the last step in reverse cholesterol transport. This phenomenon can neither be explained by increased

Dynamic controls on shallow clinoform geometry: Mekong Delta, Vietnam

Science.gov (United States)

Eidam, E. F.; Nittrouer, C. A.; Ogston, A. S.; DeMaster, D. J.; Liu, J. P.; Nguyen, T. T.; Nguyen, T. N.

2017-09-01

Compound deltas, composed of a subaerial delta plain and subaqueous clinoform, are common termini of large rivers. The transition between clinoform topset and foreset, or subaqueous rollover point, is located at 25-40-m water depth for many large tide-dominated deltas; this depth is controlled by removal of sediment from the topset by waves, currents, and gravity flows. However, the Mekong Delta, which has been classified as a mixed-energy system, has a relatively shallow subaqueous rollover at 4-6-m depth. This study evaluates dynamical measurements and seabed cores collected in Sep 2014 and Mar 2015 to understand processes of sediment transfer across the subaqueous delta, and evaluate possible linkages to geometry. During the southwest rainy monsoon (Sep 2014), high river discharge, landward return flow under the river plume, and regional circulation patterns facilitated limited sediment flux to the topset and foreset, and promoted alongshore flux to the northeast. Net observed sediment fluxes in Sep 2014 were landward, however, consistent with hypotheses about seasonal storage on the topset. During the northeast rainy monsoon, low river discharge and wind-driven currents facilitated intense landward and southwestward fluxes of sediment. In both seasons, bed shear velocities frequently exceeded the 0.01-0.02 m/s threshold of motion for sand, even in the absence of strong wave energy. Most sediment transport occurred at water depths 4 cm/yr at energy-limited, and thus rollover depths cannot be predicted solely by bed-stress distributions. In systems like the subaqueous Mekong Delta, direction of transport may have a key impact on morphology.

A new identification method for energetic ion {delta}E-E telescopes

Energy Technology Data Exchange (ETDEWEB)

Martin, Cesar [Departamento de Fisica, Universidad de Alcala, 28871 Alcala de Henares, Madrid (Spain); Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts, Universitaet zu Kiel, 24118 Kiel (Germany); Bronchalo, Enrique [Departamento de Fisica, Universidad de Alcala, 28871 Alcala de Henares, Madrid (Spain); Departamento de Fisica y Arquitectura de Computadores, Universidad Miguel Hernandez, Avda. Universidad s/n, 03202 Elche, Alicante (Spain)], E-mail: ebronchalo@umh.es; Medina, Jose [Departamento de Fisica, Universidad de Alcala, 28871 Alcala de Henares, Madrid (Spain)

2007-11-21

A new ion identification method for {delta}E-E telescopes is presented. The method works by counting data points under {delta}E(E) curves on {delta}E-E diagrams. These curves are obtained by simulating the telescope response to a flux of energetic ions. The method is checked against three published methods applied to several experimental data sets.

Inclusive production of. delta. /sup + +/(1232) in pn interactions at 19 GeV/c

Energy Technology Data Exchange (ETDEWEB)

Bakken, V.; Breivik, F.O.; Jacobsen, T.; Rudjord, A.L. (Oslo Univ. (Norway) Fysisk Inst.)

1982-12-21

We present a study of ..delta../sup + +/ production in pn interactions at 19 GeV/c, where the ..delta../sup + +/ is emitted in the protonlike (..delta..sub(F)/sup + +/) and neutron-like (..delta..sub(B)/sup + +/) c.m. hemispheres. The cross-section sigma(pn->..delta..sub(F)/sup + +/+X)=(3.09+-0.43) mb is about three times larger than sigma(pn->..delta..sub(B)/sup + +/+X)=(0.94+-0.34) mb. About 2/3 of ..delta..sub(F)/sup + +/ is peripherally produced with vertical stroketsub(p,..delta..)vertical stroke<1 (GeV/c)/sup 2/, while the cross-section for ..delta..sub(B)/sup + +/ production is nearly zero for vertical stroketsub(n,..delta..)vertical stroke<1 (GeV/c)/sup 2/. We have made a detailed study of the energy dependence of the reaction ap->..delta../sup + +/+X (a=p, anti p, n, ..pi..sup(+-), Ksup(+-)) for vertical stroketsub(p,..delta..)vertical stroke<1 (GeV/c)/sup 2/, by applying the same fitting procedure to extract the ..delta../sup + +/ cross-section to all available mass spectra. All the normalized cross-sections R=sigma(..delta../sup + +/)/sigmasub(inel) can be well described by R=R/sub 0/+R/sub 1/sup(a)psup(-..cap alpha..)sub(lab), where R/sub 0/ and ..cap alpha.. are the same for all reactions, while R/sub 1/sup(a) varies with the beam type a. The value of ..cap alpha.. is slightly below unity. The differential cross section of pn->..delta..sub(F)/sup + +/+X has been determined as a function of the variables t, t', x, y, psub(T)/sup 2/ and Msub(X)/sup 2/ both in the whole kinematical region and for vertical stroketsub(p,..delta..)vertical stroke<1 (GeV/c)/sup 2/. We show that the peripherally produced ..delta..sub(F)/sup + +/ is consistent with the dominance of the one-pion exchange mechanism. This follows from a study of the density matrix elements, the comparison of some properties of the system X with real ..pi../sup +/p data and from the results of a triple-Regge analysis.

Quaternary lacustrine braid deltas on Lake General Carrera in southern Chile Deltas entrelazados lacustres del Cuaternario en el lago General Carrera, sur de Chile

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C. Mike Bell

2009-01-01

Full Text Available A series of Quaternary lacustrine braid deltas on the shores of Lake General Carrera in southern Chile formed as a result of falls in lake level. Each delta comprises two components, the delta fan and the beach embayment, each in turn comprising an onshore subaerial and an offshore subaqueous element. The delta fans have a classic Gilbert form with a braided delta top and a steeply inclined delta front. Adjacent to the fans are concave beach embayments that formed parallel with the deltas as they prograded into the lake. The delta sediments consist predominantly of matrix- and clast-supported gravéis to a total composite thickness exceeding 400 m. The depositional environments are dominated by ephemeral river flooding and by storm-driven waves. Beach sediment is sorted, rounded, winnowed and transported alongshore by waves to fill the beach embayment with ridges of very well sorted and well-rounded gravel. A gently-dipping shoreface platform occurs up to 100 m offshore between the beach and the brink point. From the brink point, in water depth of about 8 m, sediment cascades down the steep delta front slope to form long foresets extending to the lake floor. The sedimentary successions therefore wedge in the opposite direction from those of tectonically controlled basin margins where fan growth keeps pace with basin subsidence.Una serie de deltas entrelazados lacustres, pertenecientes al Cuaternario, ubicados en las costas del lago General Carrera, en el sur de Chile, se formaron como resultado de caídas en el nivel del lago. Cada delta consta de dos componentes: el abanico deltaico y la zona de embahiamiento. Cada uno de ellos tiene, a su vez, un elemento subaéreo costero y un elemento subacuático. Los abanicos deltaicos tienen una forma Gilbert clásica con una parte superior de ríos entrelazados y un frente deltaico empinado. Adyacente a los abanicos aluviales existen bahías cóncavas de playa que se formaron de manera paralela a los

How to deal with subsidence in the Dutch delta?

NARCIS (Netherlands)

Stouthamer, E.; Erkens, G.

2017-01-01

In many deltas worldwide subsidence still is an underestimated problem, while the threat posed by land subsidence low-lying urbanizing and urbanized deltas exceeds the threat of sea-level rise induced by climate change. Human-induced subsidence is driven by the extraction of hydrocarbons and

Human influence on the sedimentation in the delta of the river Kyroenjoki, western Finland

International Nuclear Information System (INIS)

Heikkilae, R.

1999-01-01

Human activities in the drainage basin of the river Kyroenjoki, Western Finland, have greatly influenced the hydrology and sediment load of the river. The main factors have been agriculture, forestry, peat mining and watercourse works. Also sewage from towns and small-scale industry has increased the nutrient transport to the delta of the river. The aim of this study was to assess factors influencing the sedimentary conditions, sediment accumulation rates and sediment quality in the delta of the river. The sediment studies were carried out in 1983-1988 in the delta. The drainage basin of the river Kyroenjoki covers 5030 km 2 in the middle boreal vegetation zone. The river channel has been cleared many times since the 1600s to prevent floods and to allow agriculture on the adjoining land. Extensive cultivation of the paludified Litorina clay plains along the river has also continued for centuries. Forestry drainage of mires covered almost all the mires of the basin in 1960s and 1970s. Since 1963, four reservoirs and four hydroelectric power stations with daily regulation of water have been built. The estuary of the river was echo sounded, and on the basis of the results the delta was delimited, and areas of accumulation and erosion were separated. Samples of the sediment surface from 65 sites and long cores from 8 sites in the delta of the river Kyroenjoki were analysed for water content, organic content, C, N, P, Ca, Fe, Mn, Pb, Cu, Zn, Cd and Hg. The sediment from Nabbviken Bay in the delta was dated on the basis of annual laminae. The chemical analyses showed that the organic matter and heavy metal content have increased during recent decades. The heavy metal content was clearly lower than in areas polluted by industrial works. The phosphorus content of the sediment was very high. The sedimentation rate in the delta increased from the 1930s to the 1950s, due to increased land reclamation for agriculture and forestry drainage, and then decreased in the beginning

Evaluation of DELTA(1232) components in sup 1 sup 2 C

CERN Document Server

Bystritsky, V M; Krechetov, Yu F; Saigushkin, O K; Tabachenko, A N; Schuvalov, E N; Grabmayr, R; Fiks, A I

2001-01-01

One measured cross section of sup 1 sup 2 C(gamma, pi sup + p) reaction within DELTA(1232)-isobar range. Data analysis was carried out using model taking account of both nucleon and isobar degrees of freedom of sup 1 sup 2 C nucleus. One makes a conclusion that within high transmitted pulses pi sup + p-pairs are formed during DELTA sup + sup + -isobar direct knocking-out of a nucleus. One estimated the probability to determine DELTA-isobar in sup 1 sup 2 C nucleus ground state equal to 0.018 +- 0.005 DELTA-isobar per nucleon

Design Principles of A Sigma-delta Flux-gate Magnetometer

Science.gov (United States)

Magnes, W.; Valavanoglou, A.; Pierce, D.; Frank, A.; Schwingenschuh, K.

A state-of-the-art flux-gate magnetometer is characterised by magnetic field resolution of several pT in a wide frequency range, low power consumption, low weight and high robustness. Therefore, flux-gate magnetometers are frequently used for ground-based Earth's field observation as well as for measurements aboard scientific space missions. But both traditional analogue and recently developed digital flux-gate magnetometers need low power and high-resolution analogue-to-digital converters for signal quan- tization. The disadvantage of such converters is the low radiation hardness. This fact has led to the idea of combining a traditional analogue flux-gate regulation circuit with that of a discretely realized sigma-delta converter in order to get a radiation hard and further miniaturized magnetometer. The name sigma-delta converter is derived from putting an integrator in front of a 1-bit delta modulator which forms the sigma-delta loop. It is followed by a digital decimation filter realized in a field-programmable gate array (FPGA). The flux-gate regulation and the sigma-delta loop are quite similar in the way of realizing the integrator and feedback circuit, which makes it easy to com- bine these two systems. The presented talk deals with the design principles and the results of a first bread board model.

The effect of the CCR5-delta32 deletion on global gene expression considering immune response and inflammation

Directory of Open Access Journals (Sweden)

Hütter Gero

2011-10-01

Full Text Available Abstract Background The natural function of the C-C chemokine receptor type 5 (CCR5 is poorly understood. A 32 base pair deletion in the CCR5 gene (CCR5-delta32 located on chromosome 3 results in a non-functional protein. It is supposed that this deletion causes an alteration in T-cell response to inflammation. For example, the presence of the CCR5-delta32 allele in recipients of allografts constitutes as an independent and protective factor associated with a decreased risk of graft-versus-host disease (GVHD and graft rejection. However, the mechanism of this beneficial effect of the deletion regarding GVHD is unknown. In this survey we searched for a CCR5-delta32 associated regulation of critical genes involved in the immune response and the development of GVHD. Methods We examined CD34+ hematopoietic progenitor cells derived from bone marrow samples from 19 healthy volunteers for the CCR5-delta32 deletion with a genomic PCR using primers flanking the site of the deletion. Results 12 individuals were found to be homozygous for CCR5 WT and 7 carried the CCR5-delta32 deletion heterozygously. Global gene expression analysis led to the identification of 11 differentially regulated genes. Six of them are connected with mechanisms of immune response and control: LRG1, CXCR2, CCRL2, CD6, CD7, WD repeat domain, and CD30L. Conclusions Our data indicate that the CCR5-delta32 mutation may be associated with differential gene expression. Some of these genes are critical for immune response, in the case of CD30L probably protective in terms of GVHD.

Stratigraphy and Evolution of Delta Channel Deposits, Jezero Crater, Mars

Science.gov (United States)

Goudge, T. A.; Mohrig, D.; Cardenas, B. T.; Hughes, C. M.; Fassett, C. I.

2017-01-01

The Jezero impact crater hosted an open-basin lake that was active during the valley network forming era on early Mars. This basin contains a well exposed delta deposit at the mouth of the western inlet valley. The fluvial stratigraphy of this deposit provides a record of the channels that built the delta over time. Here we describe observations of the stratigraphy of the channel deposits of the Jezero western delta to help reconstruct its evolution.

Alpha-, gamma- and delta-tocopherols reduce inflammatory angiogenesis in human microvascular endothelial cells.

Science.gov (United States)

Wells, Shannon R; Jennings, Merilyn H; Rome, Courtney; Hadjivassiliou, Vicky; Papas, Konstantinos A; Alexander, Jonathon S

2010-07-01

Vitamin E, a micronutrient (comprising alpha-, beta-, gamma- and delta-tocopherols, alpha-, beta-, gamma- and delta-tocotrienols), has documented antioxidant and non-antioxidant effects, some of which inhibit inflammation and angiogenesis. We compared the abilities of alpha-, gamma- and delta-tocopherols to regulate human blood cytotoxicity (BEC) and lymphatic endothelial cytotoxicity (LEC), proliferation, invasiveness, permeability, capillary formation and suppression of TNF-alpha-induced VCAM-1 as in vitro models of inflammatory angiogenesis. alpha-, gamma- and delta-tocopherols were not toxic to either cell type up to 40 microM. In BEC, confluent cell density was decreased by all concentrations of delta- and gamma-tocopherol (10-40 microM) but not by alpha-tocopherol. LEC showed no change in cell density in response to tocopherols. delta-Tocopherol (40 microM), but not other isomers, decreased BEC invasiveness. In LEC, all doses of gamma-tocopherol, as well as the highest dose of alpha-tocopherol (40 microM), decreased cell invasiveness. delta-Tocopherol had no effect on LEC invasiveness at any molarity. delta-Tocopherol dose dependently increased cell permeability at 48 h in BEC and LEC; alpha- and gamma-tocopherols showed slight effects. Capillary tube formation was decreased by high dose (40 microM) concentrations of alpha-, gamma- and delta-tocopherol, but showed no effects with smaller doses (10-20 microM) in BEC. gamma-Tocopherol (10-20 microM) and alpha-tocopherol (10 microM), but not delta-tocopherol, increased LEC capillary tube formation. Lastly, in BEC, alpha-, gamma- and delta-tocopherol each dose-dependently reduced TNF-alpha-induced expression of VCAM-1. In LEC, there was no significant change to TNF-alpha-induced VCAM-1 expression with any concentration of alpha-, gamma- or delta-tocopherol. These data demonstrate that physiological levels (0-40 microM) of alpha-, gamma- and delta-tocopherols are nontoxic and dietary tocopherols, especially delta

Distribution of polycyclic aromatic hydrocarbons in thirty typical soil profiles in the Yangtze River Delta region, east China

International Nuclear Information System (INIS)

Ping, L.F.; Luo, Y.M.; Zhang, H.B.; Li, Q.B.; Wu, L.H.

2007-01-01

Polycyclic aromatic hydrocarbons (PAHs) were quantified in 30 soil profiles from the Yangtze River Delta Region, in east China. Relative concentrations of PAH compounds with different benzene rings and ratios of fluoranthene to fluoranthene plus pyrene and benz(a)anthracene to benz(a)anthracene plus chrysene were used to identify the possible sources of soil PAHs. Total concentrations of 15 PAHs in topsoils ranged from 8.6 to 3881 μg kg -1 with an average of 397 μg kg -1 . Half of the soil samples were considered to be contaminated with PAHs (>200 μg kg -1 ) and two sampling sites were heavily polluted by PAHs with concentrations >1000 μg kg -1 . Phenanthrene was found in soils below a depth of 100 cm in half of the sampling sites, but the detectable ratio of benzo(a)pyrene decreased sharply from 100% in topsoil to 0 in the 4th horizon. - The information was provided on levels, distributions, and possible sources of PAHs in the soils of Yangtze River Delta area

Subsidence, Sea Level Rise, and Seismicity in the Sacramento–San Joaquin Delta

Directory of Open Access Journals (Sweden)

Jeffrey Mount

2005-03-01

Full Text Available Anthropogenic accommodation space, or that space in the Delta that lies below sea level and is filled neither with sediment nor water, serves as a useful measure of the regional consequences of Delta subsidence and sea level rise. Microbial oxidation and compaction of organic-rich soils due to farming activity is the primary cause of Delta subsidence. During the period 1900-2000, subsidence created approximately 2.5 billion cubic meters of anthropogenic accommodation space in the Delta. From 2000-2050, subsidence rates will slow due to depletion of organic material and better land use practices. However, by 2050 the Delta will contain more than 3 billion cubic meters of anthropogenic accommodation space due to continued subsidence and sea level rise. An Accommodation Space Index, which relates subaqueous accommodation space to anthropogenic accommodation space, provides an indicator of past and projected Delta conditions. While subsidence and sea level rise create increasing anthropogenic accommodation space in the Delta, they also lead to a regional increase in the forces that can cause levee failure. Although these forces take many forms, a Levee Force Index can be calculated that is a proxy for the cumulative forces acting on levees. The Levee Force Index increases significantly over the next 50 years demonstrating regional increases in the potential for island flooding. Based on continuing increases in the Levee Force Index and the Accommodation Space Index, and limited support for Delta levee upgrades, there will be a tendency for increases in and impacts of island flooding, with escalating costs for repairs. Additionally, there is a two-in-three chance that 100-year recurrence interval floods or earthquakes will cause catastrophic flooding and significant change in the Delta by 2050. Currently, the California Bay-Delta Authority has no overarching policy that addresses the consequences of, and potential responses to, gradual or abrupt

The delta-Sobolev approach for modeling solar spectral irradiance and radiance

International Nuclear Information System (INIS)

Xiang, Xuwu.

1990-01-01

The development and evaluation of a solar radiation model is reported, which gives irradiance and radiance results at the bottom and top of an atmosphere of specified optical depth for each of 145 spectral intervals from 0.29 to 4.05 microns. Absorption by water vapor, aerosols, ozone, and uniformly mixed gases; scattering by molecules and aerosols; and non-Lambertian surface reflectance are included in the model. For solving the radiative transfer equation, an innovative delta-Sobolev method is developed. It applies a delta-function modification to the conventional Sobolev solutions in a way analogous to the delta-Eddington method. The irradiance solution by the delta-Sobolev method turns out to be mathematically identical to the delta-Eddington approximation. The radiance solution by the delta-Sobolov method provides a convenient way to obtain the directional distribution pattern of the radiation transfer field, a feature unable to be obtained by most commonly used approximation methods. Such radiance solutions are also especially useful in models for satellite remote sensing. The model is tested against the rigorous Dave model, which solves the radiation transfer problem by the spherical harmonic method, an accurate but very time consuming process. Good agreement between the current model results and those of Dave's model are observed. The advantages of the delta-Sobolev model are simplicity, reasonable accuracy and capability for implementation on a minicomputer or microcomputer

Morphodynamic evolution of two deltas in arctic environments, east coast of Greenland

DEFF Research Database (Denmark)

Kroon, Aart; Pedersen, Jørn Bjarke Torp; Sigsgaard, Charlotte

2011-01-01

Changes in fluvial channel patterns on deltas have a significant impact on the coastal morphology along its fringes. Lateral channel migration can locally cause cliff erosion and introduce an extra sediment source in the local budget of an active delta plain. Stabilization of channels or even...... channel lobe switching reduce the fluvial impact on the delta and introduce the formation of beach ridges and spits along the (former) delta edge. These accumulative features are formed in the ice-free summer periods and fed by alongshore sediment input from adjacent shores due to wave-driven alongshore...... currents, and by the reworking of the sediments on the delta plain by wave-driven cross-shore processes....

Transport Barkhausen-like noise in uniaxially pressed Bi{sub 1.65}Pb{sub 0.35}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+{delta}}ceramic samples

Energy Technology Data Exchange (ETDEWEB)

Garcia-Fornaris, I. [Departamento de Ciencias Basicas, Universidad de Granma, Apdo. 21, P.O. Box 85100, Bayamo (Cuba); Govea-Alcaide, E. [Departamento de Fisica, Universidad de Oriente, Patricio Lumumba s/n, P.O. Box 90500, Santiago de Cuba (Cuba); Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05315-970 Sao Paulo, SP (Brazil); Alberteris-Campos, M. [Departamento de Engenharia Mecanica, Escola Politecnica, Universidade de Sao Paulo, 05508-900 Sao Paulo, SP (Brazil); Mune, P. [Departamento de Fisica, Universidad de Oriente, Patricio Lumumba s/n, P.O. Box 90500, Santiago de Cuba (Cuba); Jardim, R.F., E-mail: rjardim@if.usp.b [Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05315-970 Sao Paulo, SP (Brazil)

2010-08-01

We report on the detection of the transport Barkhausen-like noise (TBN) in polycrystalline samples of Bi{sub 1.65}Pb{sub 0.35}Sr{sub 2}Ca{sub 2} Cu{sub 3}O{sub 10+{delta}}(Bi-2223) which were subjected to different uniaxial compacting pressures. The transport Barkhausen-like noise was measured when the sample was subjected to an ac triangular-shape magnetic field (f {approx} 1 Hz) with maximum amplitude B{sub max} {approx} 5.5 mT, in order to avoid the flux penetration within the superconducting grains. Analysis of the TBN signal, measured for several values of excitation current density, indicated that the applied magnetic field in which the noise signal first appears, B{sub a}(t{sub i}), is closely related to the magnetic-flux pinning capability of the material. The combined results are consistent with the existence of three different superconducting levels within the samples: (i) the superconducting grains; (ii) the superconducting clusters; and (iii) the weak-links. We finally argue that TBN measurements constitute a powerful tool for probing features of the intergranular transport properties in polycrystalline samples of high-T{sub c} superconductors.

Novel urinary metabolite of d-delta-tocopherol in rats

International Nuclear Information System (INIS)

Chiku, S.; Hamamura, K.; Nakamura, T.

1984-01-01

A novel metabolite of d-delta-tocopherol was isolated from the urine of rats given d-3,4-[ 3 H 2 ]-delta-tocopherol intravenously. The metabolite was collected from the urine of rats given d-delta-tocopherol in the same manner as that of the labeled compound. It was found that the metabolites consisted of sulfate conjugates. The portion of the major metabolite released with sulfatase was determined to be 2,8-dimethyl-2-(2'-carboxyethyl)-6-chromanol by infrared spectra, nuclear magnetic resonance spectra, and mass spectra. The proposed structure was confirmed by comparing the analytical results with those of a synthetically derived compound. As a result of the structural elucidation of this novel metabolite, a pathway for the biological transformation of delta-tocopherol is proposed which is different from that of alpha-tocopherol. A characteristic feature of the pathway is the absence of any opening of the chroman ring throughout the sequence

CMOS sigma-delta converters practical design guide

CERN Document Server

De la Rosa, Jose M

2013-01-01

A comprehensive overview of Sigma-Delta Analog-to-Digital Converters (ADCs) and a practical guide to their design in nano-scale CMOS for optimal performance. This book presents a systematic and comprehensive compilation of sigma-delta converter operating principles, the new advances in architectures and circuits, design methodologies and practical considerations - going from system-level specifications to silicon integration, packaging and measurements, with emphasis on nanometer CMOS implementation. The book emphasizes practical design issues - from high-level behavioural modelling i

Stratigraphy and paleohydrology of delta channel deposits, Jezero crater, Mars

Science.gov (United States)

Goudge, Timothy A.; Mohrig, David; Cardenas, Benjamin T.; Hughes, Cory M.; Fassett, Caleb I.

2018-02-01

The Jezero crater open-basin lake contains two well-exposed fluvial sedimentary deposits formed early in martian history. Here, we examine the geometry and architecture of the Jezero western delta fluvial stratigraphy using high-resolution orbital images and digital elevation models (DEMs). The goal of this analysis is to reconstruct the evolution of the delta and associated shoreline position. The delta outcrop contains three distinct classes of fluvial stratigraphy that we interpret, from oldest to youngest, as: (1) point bar strata deposited by repeated flood events in meandering channels; (2) inverted channel-filling deposits formed by avulsive distributary channels; and (3) a valley that incises the deposit. We use DEMs to quantify the geometry of the channel deposits and estimate flow depths of ∼7 m for the meandering channels and ∼2 m for the avulsive distributary channels. Using these estimates, we employ a novel approach for assessing paleohydrology of the formative channels in relative terms. This analysis indicates that the shift from meandering to avulsive distributary channels was associated with an approximately four-fold decrease in the water to sediment discharge ratio. We use observations of the fluvial stratigraphy and channel paleohydrology to propose a model for the evolution of the Jezero western delta. The delta stratigraphy records lake level rise and shoreline transgression associated with approximately continuous filling of the basin, followed by outlet breaching, and eventual erosion of the delta. Our results imply a martian surface environment during the period of delta formation that supplied sufficient surface runoff to fill the Jezero basin without major drops in lake level, but also with discrete flooding events at non-orbital (e.g., annual to decadal) timescales.

LaNiO(3) Buffer Layers for High Critical Current Density YBa(2)Cu(3)O(7-delta) and Tl(2)Ba(2)CaCu(2)O(8-delta) Films

Energy Technology Data Exchange (ETDEWEB)

Carlson, C.M.; Parilla, P.A.; Siegal, M.P.; Ginley, D.S.; Wang, Y.-T.; Blaugher, R.D.; Price, J.C.; Overmyer, D.L.; Venturini, E.L.

1999-08-24

We demonstrate high critical current density superconducting films of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) and Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8{minus}{delta}} (Tl-2212) using LaNiO{sub 3} (LNO) buffer layers. YBCO films grown on an LNO buffer layer have only a slightly lower J{sub c} (5K, H=0) than films grown directly on a bare LaAlO{sub 3} substrate. It is noteworthy that YBCO films grown on LNO buffer layers exhibit minor microstructural disorder and enhanced flux pinning. LNO-buffered Tl-2212 samples show large reductions in J{sub c} at all temperatures and fields compared to those grown on bare LaAlO{sub 3}, correlating to both a-axis grain and nonsuperconducting phase formation. With additional optimization, LNO could be a promising buffer layer for both YBCO and Tl-based superconducting films, perhaps ideally suited for coated conductor applications.

Carbon dynamics and CO2 and CH4 outgassing in the Mekong delta

Science.gov (United States)

Borges, Alberto V.; Abril, Gwenaël; Bouillon, Steven

2018-02-01

We report a data set of biogeochemical variables related to carbon cycling obtained in the three branches (Mỹ Tho, Hàm Luông, Cố Chiên) of the Mekong delta (Bến Tre province, Vietnam) in December 2003, April 2004, and October 2004. Both the inner estuary (upstream of the mouth) and the outer estuary (river plume) were sampled, as well as side channels. The values of the partial pressure of CO2 (pCO2) ranged between 232 and 4085 ppm, O2 saturation level (%O2) between 63 and 114 %, and CH4 between 2 and 2217 nmol L-1, within the ranges of values previously reported in temperate and tropical meso- and macro-tidal estuaries. Strong seasonal variations were observed. In the upper oligohaline estuary, low pCO2 (479-753 ppm) and high %O2 (98-106 %) values were observed in April 2004 most probably related to freshwater phytoplankton growth owing to low freshwater discharge (1400 m3 s-1) and increase in water residence time; during the two other sampling periods with a higher freshwater discharge (9300-17 900 m3 s-1), higher pCO2 (1895-2664 ppm) and lower %O2 (69-84 %) values were observed in the oligohaline part of the estuary. In October 2004, important phytoplankton growth occurred in the offshore part of the river plume as attested by changes in the contribution of particulate organic carbon (POC) to total suspended matter (TSM) (%POC) and the stable isotope composition of POC (δ13C-POC), possibly related to low TSM values (improvement of light conditions for phytoplankton development), leading to low pCO2 (232 ppm) and high %O2 (114 %) values. Water in the side channels in the Mekong delta was strongly impacted by inputs from the extensive shrimp farming ponds. The values of pCO2, CH4, %O2, and the stable isotope composition of dissolved inorganic carbon (δ13C-DIC) indicated intense organic matter degradation that was partly mediated by sulfate reduction in sediments, as revealed by the slope of total alkalinity (TA) and DIC covariations. The δ13C

Construction and maintenance of the Ganges-Brahmaputra-Meghna delta: linking process, morphology, and stratigraphy.

Science.gov (United States)

Wilson, Carol A; Goodbred, Steven L

2015-01-01

We present a review of the processes, morphology, and stratigraphy of the Ganges-Brahmaputra-Meghna delta (GBMD), including insights gained from detailed elevation data. The review shows that the GBMD is best characterized as a composite system, with different regions having morphologic and stratigraphic attributes of an upland fluvial fan delta; a lowland, backwater-reach delta; a downdrift tidal delta plain; and an offshore subaqueous-delta clinoform. These distinct areas of upland and lowland fluvial reaches and tidal dominance vary in time and space, and we distinguish late-Holocene phases of delta construction, maintenance, and decline similar to delta-lobe cycling in other systems. The overall stability of the GBMD landform, relative to many deltas, reflects the efficient, widespread dispersal of sediment by the large monsoon discharge and high-energy tides that affect this region. However, we do identify portions of the delta that are in decline and losing elevation relative to sea level owing to insufficient sediment delivery. These areas, some of which are well inland of the coast, represent those most at risk to the continued effect of sea-level rise.

Sigma-delta modulator modeling analysis and design

Energy Technology Data Exchange (ETDEWEB)

Ge Binjie; Wang Xin' an; Zhang Xing; Feng Xiaoxing; Wang Qingqin, E-mail: wangxa@szpku.edu.c [Key Laboratory of Integrated Microsystem Science and Engineering Applications, Shenzhen Graduate School of Peking University, Shenzhen 518055 (China)

2010-09-15

This paper introduces a new method for SC sigma-delta modulator modeling. It studies the integrator's different equivalent circuits in the integrating and sampling phases. This model uses the OP-AMP input pair's tail current (I{sub 0}) and overdrive voltage (v{sub on}) as variables. The modulator's static and dynamic errors are analyzed. A group of optimized I{sub 0} and v{sub on} for maximum SNR and power x area ratio can be obtained through this model. As examples, a MASH21 modulator for digital audio and a second order modulator for RFID baseband are implemented and tested, and they can achieve 91 dB and 72 dB respectively, which verifies the modeling and design criteria. (semiconductor integrated circuits)

Climate change and the Delta

Science.gov (United States)

Dettinger, Michael; Anderson, Jamie; Anderson, Michael L.; Brown, Larry R.; Cayan, Daniel; Maurer, Edwin P.

2016-01-01

Anthropogenic climate change amounts to a rapidly approaching, “new” stressor in the Sacramento–San Joaquin Delta system. In response to California’s extreme natural hydroclimatic variability, complex water-management systems have been developed, even as the Delta’s natural ecosystems have been largely devastated. Climate change is projected to challenge these management and ecological systems in different ways that are characterized by different levels of uncertainty. For example, there is high certainty that climate will warm by about 2°C more (than late-20th-century averages) by mid-century and about 4°C by end of century, if greenhouse-gas emissions continue their current rates of acceleration. Future precipitation changes are much less certain, with as many climate models projecting wetter conditions as drier. However, the same projections agree that precipitation will be more intense when storms do arrive, even as more dry days will separate storms. Warmer temperatures will likely enhance evaporative demands and raise water temperatures. Consequently, climate change is projected to yield both more extreme flood risks and greater drought risks. Sea level rise (SLR) during the 20th century was about 22cm, and is projected to increase by at least 3-fold this century. SLR together with land subsidence threatens the Delta with greater vulnerabilities to inundation and salinity intrusion. Effects on the Delta ecosystem that are traceable to warming include SLR, reduced snowpack, earlier snowmelt and larger storm-driven streamflows, warmer and longer summers, warmer summer water temperatures, and water-quality changes. These changes and their uncertainties will challenge the operations of water projects and uses throughout the Delta’s watershed and delivery areas. Although the effects of climate change on Delta ecosystems may be profound, the end results are difficult to predict, except that native species will fare worse than invaders. Successful

The role of Ca substitution on the nature of the superconducting transition of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}

Energy Technology Data Exchange (ETDEWEB)

Jaeckel, S.T.; Lopes, L.F.; Nunes, S.E.; Mendonca, A.P.A.; Lopes, R.F.; Vieira, V.N. [Universidade Federal de Pelotas, RS (Brazil). Inst. de Fisica e Matematica; Pureur, P.; Pimentel Junior, J.L.; Rosa, F.M. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Fisica; Ferreira, L.M. [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Ciencias Naturais e Humanas

2012-07-01

Full text: In this work we report the results of an experimental study about the superconducting transition of Ca- doped YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}samples. Temperature dependent in-plane resistivity measurements were carried out on Y{sub 1-x}Ca{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} single crystals with Ca content x = 0, 0.01, 0.05, 0.10. The samples were studied under hydrostatic pressure conditions (P {<=}15 kbar) and applied magnetic fields (H {<=} 2500 Oe) with H parallel to the c-axis. From the analysis of the contribution of superconducting fluctuations to the electrical conductivity we identified a fluctuation regime described by the small exponent {lambda}{sub cr} = 0.20 in a narrow temperature range immediately above the critical temperature. The origin of this fluctuation regime is still unclear. A possibility is that it may be a precursor to a weakly first-order pairing transition. The evolution of this super-critical regime with pressure and magnetic field for our Ca-doped samples is distinct from results reported in the literature for pure and other divalent substituted YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}samples. Our results indicate that Ca doping favors the stabilization of the super-critical regime. (author)

Auditory stream segregation using bandpass noises: evidence from event-related potentials

Directory of Open Access Journals (Sweden)

Yingjiu eNie

2014-09-01

Full Text Available The current study measured neural responses to investigate auditory stream segregation of noise stimuli with or without clear spectral contrast. Sequences of alternating A and B noise bursts were presented to elicit stream segregation in normal-hearing listeners. The successive B bursts in each sequence maintained an equal amount of temporal separation with manipulations introduced on the last stimulus. The last B burst was either delayed for 50% of the sequences or not delayed for the other 50%. The A bursts were jittered in between every two adjacent B bursts. To study the effects of spectral separation on streaming, the A and B bursts were further manipulated by using either bandpass-filtered noises widely spaced in center frequency or broadband noises. Event-related potentials (ERPs to the last B bursts were analyzed to compare the neural responses to the delay vs. no-delay trials in both passive and attentive listening conditions. In the passive listening condition, a trend for a possible late mismatch negativity (MMN or late discriminative negativity (LDN response was observed only when the A and B bursts were spectrally separate, suggesting that spectral separation in the A and B burst sequences could be conducive to stream segregation at the pre-attentive level. In the attentive condition, a P300 response was consistently elicited regardless of whether there was spectral separation between the A and B bursts, indicating the facilitative role of voluntary attention in stream segregation. The results suggest that reliable ERP measures can be used as indirect indicators for auditory stream segregation in conditions of weak spectral contrast. These findings have important implications for cochlear implant (CI studies – as spectral information available through a CI device or simulation is substantially degraded, it may require more attention to achieve stream segregation.

Holocene Flexural Deformation over the Nile Delta: Evidence from Radar Interferometry

Science.gov (United States)

Gebremichael, E.; Sultan, M.; Becker, R.

2017-12-01

Isostatic adjustment and subsequent subsidence and uplift due to sediment and water loading and unloading mechanisms is one of the major factors that produce regional deformational patterns across river deltas. Using 84 Envisat ASAR scenes that were acquired (2004 - 2010) along three tracks and applying Persistent scatterer (PS) radar interferometric techniques, we documented flexural deformational patterns over the entire Nile Delta (length: 186 km; width: 240 km) of Egypt. The passive continental margin of Africa subsided from Jurassic time onwards due to isostatic loading creating an accommodation space and consequently, the deposition of relatively younger sediments on the oceanic crust. In river deltas, the flexural isostasy model dictates that a subsidence in the oceanic crust side should be balanced by a bulge (uplift) in the flanking regions. Using radar interferometry, we were able to identify the flexural deformation pattern and map its spatial extent over the northern and central Nile Delta region. Findings include: (1) the northern Nile Delta region (block) is separated from the southern delta region by an east-west trending, extensively faulted, hinge line that signifies the boundary between two deformational patterns (subsidence and uplift). It separates the highly subsiding (up to 9.8 mm/yr) northern delta block (up to 85 km long) from the nearly stable (0.4 mm/yr; averaged) southern delta block (up to 91 km long). The hinge line marks the end of the passive continental margin of Africa and the beginning of the oceanic crust of the Mediterranean. (2) We mapped the extent of a 20-40 km wide flexural uplift zone to the south of the hinge line. Within the flexural uplift zone (2.5 mm/yr; averaged), there is a gradual increase in uplift rate reaching peak value (up to 7 mm/yr) near the midpoint of the zone. (3) The uplift rate gradually decreases south of the flexure boundary reaching 0.3 mm/yr at the southern periphery of the delta. (4) The flexural

GPR signal enhancement using band-pass and K–L filtering: a case study for the evaluation of grout in a shielded tunnel

International Nuclear Information System (INIS)

Xie, Xiongyao; Zeng, Chenchao; Wang, Zhigao

2013-01-01

The rapidness, non-destructiveness and high precision of ground penetrating radar (GPR) technology has enabled it to be widely and increasingly used in tunnel detection. However, data acquisition was usually restricted by physical and many other limitations. In order to improve the signal-to-noise ratio, band-pass and Karhunen–Loève (K–L) filtering are recommended. An evaluation of Yingbin No. 3 Road Tunnel is presented to illustrate the effectiveness of GPR in the inspection of the thickness of the grouting layer behind the segment and the function of the two methods mentioned above. The advantages and limitations of these two processing methods are discussed in this paper and suggestions are provided. (paper)

Upper-Division Student Difficulties with the Dirac Delta Function

Science.gov (United States)

Wilcox, Bethany R.; Pollock, Steven J.

2015-01-01

The Dirac delta function is a standard mathematical tool that appears repeatedly in the undergraduate physics curriculum in multiple topical areas including electrostatics, and quantum mechanics. While Dirac delta functions are often introduced in order to simplify a problem mathematically, students still struggle to manipulate and interpret them.…

Downstream hydraulic geometry of a tidally influenced river delta

NARCIS (Netherlands)

Sassi, M.G.; Hoitink, A.J.F.; Brye, de B.; Deleersnijder, E.

2012-01-01

Channel geometry in tidally influenced river deltas can show a mixed scaling behavior between that of river and tidal channel networks, as the channel forming discharge is both of river and tidal origin. We present a method of analysis to quantify the tidal signature on delta morphology, by

Homosexuality amongst migrant oil workers in the Niger Delta ...

African Journals Online (AJOL)

Aims: To determine the prevalence of homosexuality among migrant oil workers in Niger Delta. Methods: A prospective questionnaire – based study was conducted among migrant oil workers in the Niger Delta region of Nigeria. The design was to determine the prevalence of homosexuality in the workers in oil workers.

Development and performance of prototype serologic and molecular tests for hepatitis delta infection.

Science.gov (United States)

Coller, Kelly E; Butler, Emily K; Luk, Ka-Cheung; Rodgers, Mary A; Cassidy, Michael; Gersch, Jeffrey; McNamara, Anne L; Kuhns, Mary C; Dawson, George J; Kaptue, Lazare; Bremer, Birgit; Wedemeyer, Heiner; Cloherty, Gavin A

2018-02-01

Worldwide, an estimated 5% of hepatitis B virus (HBV) infected people are coinfected with hepatitis delta virus (HDV). HDV infection leads to increased mortality over HBV mono-infection, yet HDV diagnostics are not widely available. Prototype molecular (RNA) and serologic (IgG) assays were developed for high-throughput testing on the Abbott m2000 and ARCHITECT systems, respectively. RNA detection was achieved through amplification of a ribozyme region target, with a limit of detection of 5 IU/ml. The prototype serology assay (IgG) was developed using peptides derived from HDV large antigen (HDAg), and linear epitopes were further identified by peptide scan. Specificity of an HBV negative population was 100% for both assays. A panel of 145 HBsAg positive samples from Cameroon with unknown HDV status was tested using both assays: 16 (11.0%) had detectable HDV RNA, and 23 (15.7%) were sero-positive including the 16 HDV RNA positive samples. Additionally, an archival serial bleed panel from an HDV superinfected chimpanzee was tested with both prototypes; data was consistent with historic testing data using a commercial total anti-Delta test. Overall, the two prototype assays provide sensitive and specific methods for HDV detection using high throughput automated platforms, allowing opportunity for improved diagnosis of HDV infected patients.

Continuous time sigma delta ADC design and non-idealities analysis

International Nuclear Information System (INIS)

Yuan Jun; Chen Zhenhai; Yang Yintang; Zhang Zhaofeng; Wu Jun; Wang Chao; Qian Wenrong

2011-01-01

A wide bandwidth continuous time sigma delta ADC is implemented in 130 nm CMOS. A detailed non-idealities analysis (excess loop delay, clock jitter, finite gain and GBW, comparator offset and DAC mismatch) is performed developed in Matlab/Simulink. This design is targeted for wide bandwidth applications such as video or wireless base-stations. Athird-order continuous time sigma delta modulator comprises a third-order RC operational-amplifier-based loop filter and 3-bit internal quantizer operated at 512 MHz clock frequency. The sigma delta ADC achieves 60 dB SNR and 59.3 dB SNDR over a 16-MHz signal band at an OSR of 16. The power consumption of the CT sigma delta modulator is 22 mW from the 1.2-V supply. (semiconductor integrated circuits)

Soil Organic Carbon Stocks in Arctic Deltaic Sediments: Investigations in the Lena River Delta.

Science.gov (United States)

Zubrzycki, S.; Kutzbach, L.; Desyatkin, A.; Pfeiffer, E.-M.

2012-04-01

The soil organic carbon stock (SSOC) of deltaic sediments in arctic permafrost regions is known to be significant but is insufficiently investigated so far. Previous SSOC studies were conducted mainly in the comparatively well studied Mackenzie River Delta (area: 13,000 km2) in Canada. The few studies from other arctic delta regions report only the gravimetric carbon (C) contents and are limited to the active layer depth at the time of sampling. Since C deposits in permafrost regions are likely to become a future C source, more detailed investigations of the presently frozen likely carbon-rich sediment and soil layers in other arctic delta regions are of importance. Our investigations were performed on Samoylov Island in the southern-central part of the Lena River Delta (32,000 km2) which is the largest arctic delta and the fifth largest delta worldwide. Samoylov Island is representative for the Lena River Delta's first terrace and the active floodplains. Within this study a new portable Snow-Ice-Permafrost-Research-Establishment (SIPRE) auger was used during a spring field session to obtain 1 m deep frozen soil cores (n = 37) distributed over all known soil and vegetation units. These cores are analyzed for bulk contents of nitrogen (N) and C, ice content and bulk density (BD) and to determine the SSOC including the rarely investigated currently permanently frozen layers up to 1 m depth on Samoylov Island. Our study provides evidence for high SSOC for a depth of 1 m for the investigated area ranging between 6 kg m2 and 54 kg m2. Considering the spatial extent of different soil units on the two geomorphological units of Samoylov Island, the area-weighted average SSOC were 31 kg m2 (n = 31) for the first terrace and 15 kg m2 (n = 6) for the active floodplain. For the correspondent soil units of Turbels and Orthels in circumpolar permafrost regions, Tarnocai et al. 2009 reported a mean SSOC of 27 kg m2 (min: 0.1 kg m2, max: 126 kg m2) for a depth of 1 m. For up

DELTA-5-ANDROSTENEDIOL AND ITS SULFATE IN SERUM AND URINE OF NORMAL ADULTS AND PATIENTS WITH ENDOCRINE DISEASES

NARCIS (Netherlands)

DIKKESCHEI, LD; WILLEMSE, PHB; WOLTHERS, BG; DERUYTERBUITENHUIS, AW; NAGEL, GT

1993-01-01

OBJECTIVES We evaluated the role of delta-5-androstenediol (adiol) and its sulphates in health and endocrine diseases. DESIGN Serum and urine samples from healthy adult men and pre and post-menopausal women were analysed by gas chromatography-mass spectrometry to establish reference values. In

New decision criteria for selecting delta check methods based on the ratio of the delta difference to the width of the reference range can be generally applicable for each clinical chemistry test item.

Science.gov (United States)

Park, Sang Hyuk; Kim, So-Young; Lee, Woochang; Chun, Sail; Min, Won-Ki

2012-09-01

Many laboratories use 4 delta check methods: delta difference, delta percent change, rate difference, and rate percent change. However, guidelines regarding decision criteria for selecting delta check methods have not yet been provided. We present new decision criteria for selecting delta check methods for each clinical chemistry test item. We collected 811,920 and 669,750 paired (present and previous) test results for 27 clinical chemistry test items from inpatients and outpatients, respectively. We devised new decision criteria for the selection of delta check methods based on the ratio of the delta difference to the width of the reference range (DD/RR). Delta check methods based on these criteria were compared with those based on the CV% of the absolute delta difference (ADD) as well as those reported in 2 previous studies. The delta check methods suggested by new decision criteria based on the DD/RR ratio corresponded well with those based on the CV% of the ADD except for only 2 items each in inpatients and outpatients. Delta check methods based on the DD/RR ratio also corresponded with those suggested in the 2 previous studies, except for 1 and 7 items in inpatients and outpatients, respectively. The DD/RR method appears to yield more feasible and intuitive selection criteria and can easily explain changes in the results by reflecting both the biological variation of the test item and the clinical characteristics of patients in each laboratory. We suggest this as a measure to determine delta check methods.

Investigation of the biodistribution, breakdown and excretion of delta inulin adjuvant.

Science.gov (United States)

Wang, Lixin; Barclay, Thomas; Song, Yunmei; Joyce, Paul; Sakala, Isaac G; Petrovsky, Nikolai; Garg, Sanjay

2017-08-03

Insoluble, nanostructured delta inulin particles enhance the immunogenicity of co-administered protein antigens and consequently are used as a vaccine adjuvant (Advax™). To better understand their immunomodulatory properties, the in vitro hydrolysis and in vivo distribution of delta inulin particles were investigated. Delta inulin particle hydrolysis under bio-relevant acidic conditions resulted in no observable change to the bulk morphology using SEM, and HPLC results showed that only 6.1% of the inulin was hydrolysed over 21days. However, 65% of the terminal glucose groups were released, showing that acid hydrolysis relatively rapidly releases surface bound chemistries. This was used to explain in vivo biodistribution results in which delta inulin particles surface-labelled with fluorescein-5-thiosemicabizide were administered to mice using intramuscular (I.M.) or subcutaneous (S.C.) routes. Comparison analysis of the fluorescence of soluble inulin in the supernatants of homogenised tissues maintained at room temperature or heated to 100°C to solubilise particulate inulin was used to distinguish between fluorescent probe on soluble inulin and probe bound to inulin within particles. Following both I.M. and S.C. injection delta inulin exhibited a depot behaviour with local injection site residence for several weeks. Over this time, as injection site inulin reduced, there was measurable transport of intact delta inulin particles by macrophages to secondary lymphoid organs and the liver. Ultimately, the injected delta inulin became solubilised resulting in its detection in the plasma and in the urine. Thus injected delta inulin particles are initially taken up by macrophages at the site of injection, trafficked to secondary lymphoid tissue and the liver, and hydrolysed resulting in their becoming soluble and diffusing into the blood stream, from whence they are glomerularly filtered and excreted into the urine. These results provide important insights into the

Inhabiting the Delta: A Landscape Approach to Transformative Socio-Ecological Restoration

Directory of Open Access Journals (Sweden)

Brett Milligan

2017-09-01

Full Text Available doi: https://doi.org/10.15447/sfews.2017v15iss3art3Current legislation and plans for the Sacramento–San Joaquin Delta (Delta call for large-scale restoration of aquatic and terrestrial habitats, which will require significant changes in waterways, land uses, and cultural patterns. These re-made landscapes will be subject to a variety of new human uses, which Delta planning and adaptive management literature has yet to adequately consider. Failing to account for human uses and evolving place values can lead to diminished performance and public support for Delta restoration efforts. Our empirical study examined restored and naturalized Delta landscapes using an integrative landscape approach that seeks to reconcile multiple goals and land-use agendas that span ecological, social, economic, and political domains. The research design consisted of six overlapping methods that included a planning, policy, and law review specific to the Delta; surveys and interviews with approximately 100 land managers, scientists, land-owners, law-enforcement personnel, agency representatives, and Delta residents; nine case studies of restored and naturalized delta landscapes; GIS mapping; and extensive field work. Findings derived from the synthesis of these methods show that human uses of the Delta’s re-wilded landscapes are diverse and pervasive. Given the infrastructural and urbanized context of the region, these environments are subject to multiple and sometimes conflicting uses, perceptions, and place values. Though these myriad uses cannot be fully predicted or controlled (nor should they be, findings showed that more proactive and inclusive planning for human uses can encourage or discourage particular uses while also building constituency, support, and active engagement in ecological restoration efforts. We conclude that reconciling human uses with ecological recovery in the Delta will require a more localized, multi-functional, and creative approach to

Experimental transonic flutter characteristics of two 72 deg-sweep delta-wing models

Science.gov (United States)

Doggett, Robert V., Jr.; Soistmann, David L.; Spain, Charles V.; Parker, Ellen C.; Silva, Walter A.

1989-01-01

Transonic flutter boundaries are presented for two simple, 72 deg. sweep, low-aspect-ratio wing models. One model was an aspect-ratio 0.65 delta wing; the other model was an aspect-ratio 0.54 clipped-delta wing. Flutter boundaries for the delta wing are presented for the Mach number range of 0.56 to 1.22. Flutter boundaries for the clipped-delta wing are presented for the Mach number range of 0.72 to 0.95. Selected vibration characteristics of the models are also presented.

Radiocarbon dating of VIRI bone samples using ultrafiltration

Energy Technology Data Exchange (ETDEWEB)

Minami, Masayo, E-mail: minami@nendai.nagoya-u.ac.jp [Center for Chronological Research, Nagoya University, Nagoya 464-8602 (Japan); Yamazaki, Kana [Faculty of Science, Nagoya University, Nagoya 464-8602 (Japan); Omori, Takayuki [University Museum, University of Tokyo, Tokyo 113-0033 (Japan); Nakamura, Toshio [Center for Chronological Research, Nagoya University, Nagoya 464-8602 (Japan)

2013-01-15

Ultrafiltration can effectively remove low-molecular-weight (LMW) contaminants from bone gelatin to extract high-molecular-weight (HMW) proteins that are derived from original bone collagen, though it cannot remove HMW collagen crosslinked with humic acids. Therefore, ultrafiltration is often used to obtain more accurate {sup 14}C dates of bones. However, ultrafiltration may introduce new contaminants to bone gelatins, mainly from ultrafilters used. To study the effects of ultrafiltration on {sup 14}C age, we analyzed the C/N ratio, {delta}{sup 13}C{sub PDB} and {delta}{sup 15}N{sub AIR} values, and {sup 14}C ages of acid-soluble bone collagen obtained by decalcification, gelatin extracted from acid-insoluble bone collagen, and the HMW gelatin and LMW fractions produced during ultrafiltration of the extracted gelatin. Bone samples from the Fifth International Radiocarbon Intercomparison (VIRI) were used: VIRI-E (mammoth), -F (horse), -G (human), and -I (whale). In this study, carbon and nitrogen content and gelatin yields were used to evaluate collagen preservation in the VIRI bone samples. Radiocarbon ages, {delta}{sup 13}C{sub PDB} and {delta}{sup 15}N{sub AIR} values of unfiltered and HMW gelatins were obtained and compared with the published consensus values. The LMW fraction was found to exhibit different values from those of the other fractions, indicating the possible presence of extraneous contamination. The Vivaspin Trade-Mark-Sign 6 ultrafilters used in this study were analyzed and radiocarbon dated both before and after cleaning. We present evidence to suggest that LMW fraction contaminants could be derived from the ultrafilters rather than humic substances. Excessively long ultrafiltration time was suspected to have contaminated the bone samples with material from the ultrafilter, because those samples exhibited older {sup 14}C ages than did those filtered for shorter durations. The results in this study indicate that {sup 14}C ages of unfiltered

Sediment budgets, transport, and depositional trends in a large tidal delta

Science.gov (United States)

Morgan, Tara; Wright, Scott A.

2016-01-01

The Sacramento-San Joaquin Delta is the largest delta on the west coast of the United States. It is formed where the confluence of California’s two largest rivers (the Sacramento and San Joaquin) meet the ocean tides and has a significant physical gradient from fluvial to tidal. It is a semidiurnal system (two high and two low tides per day). Today, the Delta is one of the most manipulated in the United States. Once composed of many shallow, meandering and braided dendritic channels and dead-end sloughs and wetlands, it is now a network of leveed canals moving clear water around subsided islands. It historically has supported a biologically diverse tidal wetland complex, of which only 3% remains today (Whipple et al., 2012). It has also witnessed a collapse in the native fish populations. The Delta provides critical habitat for native species, however the hydrology and water quality are complicated by manipulations and diversions to satisfy multiple statewide objectives. Today water managers face co-equal goals of water supply to Californians and maintenance of ecosystem health and function. The Delta is a hub for both a multi-hundred-million dollar agricultural industry and a massive north-to-south water delivery system, supplying the primary source of freshwater to Central Valley farmers and drinking water for two-thirds of California’s population. Large pump facilities support the water demand and draw water from the Delta, further altering circulation patterns and redirecting the net flow toward the export facilities (Monsen et al., 2007). Fluvial sedimentation, along with organic accumulation, creates and sustains the Delta landscape. Hydraulic mining for gold in the watershed during the late 1800s delivered an especially large sediment pulse to the Delta. More recently, from 1955 to the present, a significant sediment decline has been observed that is thought to have been caused mostly by the construction of water storage reservoirs that trap the upstream

Entrepreneurship Education in Delta State Tertiary Institution as a Means of Achieving National Growth and Development

Science.gov (United States)

Osakwe, Regina N.

2015-01-01

This study examined entrepreneurship education in Delta Sate tertiary institutions as a means of national growth and development. Two research questions were asked to guide the study. The population comprised all the 1,898 academic staff in eight tertiary institutions in the state. A sample of 800 lecturers was drawn through the multi stage and…

Relationship between characteristics of fan-delta sandstone bodies and in-situ leachable sandstone-type uranium mineralization

International Nuclear Information System (INIS)

Nie Fengjun; Zhou Weixun; Guan Taiyang; Li Sitian

2000-01-01

Like normal deltas, fan-deltas are composed of three parts, i.e., fan-delta plain, fan-delta front and pre-fin-delta, In-situ leachable uranium deposits are commonly distributed along the margins of in-land basins. The author analyzes the possible relationship between the basic characteristics of fan-delta sandstone bodies and uranium mineralization. Two examples, e.g., the fan delta depositional systems in the eastern part of Jungger basin and the southern part of Yili basin, are given to illustrate the fan-delta vertical sequence and planar distribution of sedimentary facies. It has been pointed out that the braided channel sandstone bodies on delta plain, sub-aqueous distributional channel sandstone bodies and delta front sandstone bodies may be the favourable host rocks for in-situ leachable sandstone uranium deposits

Recent coarsening of sediments on the southern Yangtze subaqueous delta front: A response to river damming

Science.gov (United States)

Yang, H. F.; Yang, S. L.; Meng, Y.; Xu, K. H.; Luo, X. X.; Wu, C. S.; Shi, B. W.

2018-03-01

After more than 50,000 dams were built in the Yangtze basin, especially the Three Gorges Dam (TGD) in 2003, the sediment discharge to the East China Sea decreased from 470 Mt/yr before dams to the current level of 140 Mt/yr. The delta sediment's response to this decline has interested many researchers. Based on a dataset of repeated samplings at 44 stations in this study, we compared the surficial sediment grain sizes in the southern Yangtze subaqueous delta front for two periods: pre-TGD (1982) and post-TGD (2012). External factors of the Yangtze River, including water discharge, sediment discharge and suspended sediment grain size, were analysed, as well as wind speed, tidal range and wave height of the coastal ocean. We found that the average median size of the sediments in the delta front coarsened from 8.0 μm in 1982 to 15.4 μm in 2012. This coarsening was accompanied by a decrease of clay components, better sorting and more positive skewness. Moreover, the delta morphology in the study area changed from an overall accretion of 1.0 cm/yr to an erosion of - 0.6 cm/yr. At the same time, the riverine sediment discharge decreased by 70%, and the riverine suspended sediment grain size increased from 8.4 μm to 10.5 μm. The annual wind speed and wave height slightly increased by 2% and 3%, respectively, and the tidal range showed no change trend. Considering the increased wind speed and wave height, there was no evidence that the capability of the China Coastal Current to transport sediment southward has declined in recent years. The sediment coarsening in the Yangtze delta front was thus mainly attributed to the delta's transition from accumulation to erosion which was originally generated by river damming. These findings have important implications for sediment change in many large deltaic systems due to worldwide human impacts.

Mercury accumulation and attenuation at a rapidly forming delta with a point source of mining waste

Energy Technology Data Exchange (ETDEWEB)

Johnson, Bryce E., E-mail: bjohnson@ce.berkeley.edu [Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States); Esser, Bradley K. [Chemical Sciences Division, 7000 East Avenue, Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Whyte, Dyan C.; Ganguli, Priya M.; Austin, Carrie M. [California Regional Water Quality Control Board, 1515 Clay St., Suite 1400, Oakland, CA 94612 (United States); Hunt, James R. [Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

2009-09-01

The Walker Creek intertidal delta of Tomales Bay, California is impacted by a former mercury mine within the watershed. Eleven short sediment cores (10 cm length) collected from the delta found monomethylmercury (MMHg) concentrations ranging from 0.3 to 11.4 ng/g (dry wt.), with lower concentrations occurring at the vegetated marsh and upstream channel locations. Algal mats common to the delta's sediment surface had MMHg concentrations ranging from 7.5 to 31.5 ng/g, and the top 1 cm of sediment directly under the mats had two times greater MMHg concentrations compared to adjacent locations without algal covering. Spatial trends in resident biota reflect enhanced MMHg uptake at the delta compared to other bay locations. Eighteen sediment cores, 1 to 2 m deep, collected from the 1.2 km{sup 2} delta provide an estimate of a total mercury (Hg) inventory of 2500 {+-} 500 kg. Sediment Hg concentrations ranged from pre-mining background conditions of approximately 0.1 {mu}g/g to a post-mining maximum of 5 {mu}g/g. Sediment accumulation rates were determined from three sediment cores using measured differences of {sup 137}Cs activity. We estimate a pre-mining Hg accumulation of less than 20 kg/yr, and a period of maximum Hg accumulation in the 1970s and 1980s with loading rates greater than 50 kg/yr, corresponding to the failure of a tailings dam at the mine site. At the time of sampling (2003) over 40 kg/yr of Hg was still accumulating at the delta, indicating limited recovery. We attribute observed spatial evolution of elevated Hg levels to ongoing inputs and sediment re-working, and estimate the inventory of the anthropogenic fraction of total Hg to be at least 1500 {+-} 300 kg. We suggest ongoing sediment inputs and methylation at the deltaic surface support enhanced mercury levels for resident biota and transfer to higher trophic levels throughout the Bay.

N-Type delta Doping of High-Purity Silicon Imaging Arrays

Science.gov (United States)

Blacksberg, Jordana; Hoenk, Michael; Nikzad, Shouleh

2005-01-01

A process for n-type (electron-donor) delta doping has shown promise as a means of modifying back-illuminated image detectors made from n-doped high-purity silicon to enable them to detect high-energy photons (ultraviolet and x-rays) and low-energy charged particles (electrons and ions). This process is applicable to imaging detectors of several types, including charge-coupled devices, hybrid devices, and complementary metal oxide/semiconductor detector arrays. Delta doping is so named because its density-vs.-depth characteristic is reminiscent of the Dirac delta function (impulse function): the dopant is highly concentrated in a very thin layer. Preferably, the dopant is concentrated in one or at most two atomic layers in a crystal plane and, therefore, delta doping is also known as atomic-plane doping. The use of doping to enable detection of high-energy photons and low-energy particles was reported in several prior NASA Tech Briefs articles. As described in more detail in those articles, the main benefit afforded by delta doping of a back-illuminated silicon detector is to eliminate a "dead" layer at the back surface of the silicon wherein high-energy photons and low-energy particles are absorbed without detection. An additional benefit is that the delta-doped layer can serve as a back-side electrical contact. Delta doping of p-type silicon detectors is well established. The development of the present process addresses concerns specific to the delta doping of high-purity silicon detectors, which are typically n-type. The present process involves relatively low temperatures, is fully compatible with other processes used to fabricate the detectors, and does not entail interruption of those processes. Indeed, this process can be the last stage in the fabrication of an imaging detector that has, in all other respects, already been fully processed, including metallized. This process includes molecular-beam epitaxy (MBE) for deposition of three layers, including

Frequency of CCR5 Delta-32 Mutation in Human Immunodeficiency Virus (HIV-seropositive and HIV-exposed Seronegative Individuals and in General Population of Medellin, Colombia

Directory of Open Access Journals (Sweden)

Francisco J Díaz

2000-04-01

Full Text Available Repeated exposure to human immunodeficiency virus (HIV does not always result in seroconversion. Modifications in coreceptors for HIV entrance to target cells are one of the factors that block the infection. We studied the frequency of Delta-32 mutation in ccr5 gene in Medellin, Colombia. Two hundred and eighteen individuals distributed in three different groups were analyzed for Delta-32 mutation in ccr5 gene by polymerase chain reaction (PCR: 29 HIV seropositive (SP, 39 exposed seronegative (ESN and 150 individuals as a general population sample (GPS. The frequency of the Delta-32 mutant allele was 3.8% for ESN, 2.7% for GPS and 1.7% for SP. Only one homozygous mutant genotype (Delta-32/Delta-32 was found among the ESN (2.6%. The heterozygous genotype (ccr5/Delta-32 was found in eight GPS (5.3%, in one SP (3.4% and in one ESN (2.6%. The differences in the allelic and genotypic frequencies among the three groups were not statistically significant. A comparison between the expected and the observed genotypic frequencies showed that these frequencies were significantly different for the ESN group, which indirectly suggests a protective effect of the mutant genotype (Delta-32/Delta-32. Since this mutant genotype explained the resistance of infection in only one of our ESN persons, different mechanisms of protection must be playing a more important role in this population.

A COMPLETE SAMPLE OF BRIGHT SWIFT LONG GAMMA-RAY BURSTS. I. SAMPLE PRESENTATION, LUMINOSITY FUNCTION AND EVOLUTION

Energy Technology Data Exchange (ETDEWEB)

Salvaterra, R. [INAF, IASF Milano, via E. Bassini 15, I-20133 Milano (Italy); Campana, S.; Vergani, S. D.; Covino, S.; D' Avanzo, P.; Fugazza, D.; Ghirlanda, G.; Ghisellini, G.; Melandri, A.; Sbarufatti, B.; Tagliaferri, G. [INAF, Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate (Saint Lucia) (Italy); Nava, L. [SISSA, via Bonomea 265, I-34136 Trieste (Italy); Flores, H. [Laboratoire GEPI, Observatoire de Paris, CNRS-UMR8111, Univ. Paris-Diderot 5 place Jules Janssen, 92195 Meudon (France); Piranomonte, S., E-mail: ruben@lambrate.inaf.it [INAF, Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monte Porzio Catone, Rome (Italy)

2012-04-10

We present a carefully selected sub-sample of Swift long gamma-ray bursts (GRBs) that is complete in redshift. The sample is constructed by considering only bursts with favorable observing conditions for ground-based follow-up searches, which are bright in the 15-150 keV Swift/BAT band, i.e., with 1-s peak photon fluxes in excess to 2.6 photons s{sup -1} cm{sup -2}. The sample is composed of 58 bursts, 52 of them with redshift for a completeness level of 90%, while another two have a redshift constraint, reaching a completeness level of 95%. For only three bursts we have no constraint on the redshift. The high level of redshift completeness allows us for the first time to constrain the GRB luminosity function and its evolution with cosmic times in an unbiased way. We find that strong evolution in luminosity ({delta}{sub l} = 2.3 {+-} 0.6) or in density ({delta}{sub d} = 1.7 {+-} 0.5) is required in order to account for the observations. The derived redshift distributions in the two scenarios are consistent with each other, in spite of their different intrinsic redshift distributions. This calls for other indicators to distinguish among different evolution models. Complete samples are at the base of any population studies. In future works we will use this unique sample of Swift bright GRBs to study the properties of the population of long GRBs.

Carbon Stocks in Permafrost-Affected Soils of the Lena River Delta

Science.gov (United States)

Zubrzycki, S.; Kutzbach, L.; Grosse, G.; Desyatkin, A.; Pfeiffer, E.

2012-12-01

The soil organic carbon stock (SSOC) of soils in arctic permafrost regions is known to be significant but is insufficiently investigated so far. Previous SSOC studies report mainly the gravimetric carbon (C) contents and are limited to the active layer depth at the time of sampling. Since C deposits in permafrost regions are likely to become a future C source, more detailed investigations of the presently frozen likely carbon-rich sediment and soil layers are of importance. Our investigations were performed on Samoylov Island in the southern-central part of the Lena River Delta (32,000 km2) which is the largest arctic delta and the fifth largest delta worldwide. Samoylov Island is representative for the Lena River Delta's first terrace and the active floodplains. Within this study a new portable Snow-Ice-Permafrost-Research-Establishment (SIPRE) auger was used during a spring field session to obtain 1 m deep frozen soil cores (n = 29) distributed over all known soil and vegetation units. These cores are analyzed for bulk contents of nitrogen (N) and C, ice content and bulk density (BD) and to determine the SSOC including the rarely investigated currently permanently frozen layers up to 1 m depth on Samoylov Island. Our study provides evidence for high SSOC for a depth of 1 m for the investigated area ranging between 7 kg m-2 and 48 kg m-2. Considering the spatial extent of different soil units on the two geomorphological units of Samoylov Island, the area-weighted average SSOC were 29 kg m-2 (n = 22) for the first terrace and 14 kg m-2 (n = 7) for the active floodplain. For the correspondent soil units of Turbels and Orthels in circumpolar permafrost regions a mean SSOC of 27 kg m-2 (min: 0.1 kg m-2, max: 126 kg m-2) for a depth of 1 m was reported [1]. For up-scaling solely over the soil-covered areas of the Lena River Delta, we excluded all water bodies >3,600 m2 from the geomorphological units studied (first river terrace and the active floodplains) and

Anadromous salmonids in the Delta: New science 2006–2016

Science.gov (United States)

Perry, Russell W.; Buchanan, Rebecca A.; Brandes, Patricia L.; Burau, Jon R.; Israel, Joshua A

2016-01-01

As juvenile salmon enter the Sacramento–SanJoaquin River Delta (“the Delta”) they disperse among its complex channel network where they are subject to channel-specific processes that affect their rate of migration, vulnerability to predation, feeding success, growth rates, and ultimately, survival. In the decades before 2006, tools available to quantify growth, dispersal, and survival of juvenile salmon in this complex channel network were limited.Fortunately, thanks to technological advances such as acoustic telemetry and chemical and structural otolith analysis, much has been learned over the past decade about the role of the Delta in the life cycle of juvenile salmon. Here, we review new science between 2006and 2016 that sheds light on how different life stages and runs of juvenile salmon grow, move, and survive in the complex channel network of the Delta. One of the most important advances during the past decade has been the widespread adoption of acoustic telemetry techniques. Use of telemetry has shed light on how survival varies among alternative migration routes and the proportion of fish that use each migration route. Chemical and structural analysis of otoliths has provided insights about when juveniles left their natal river and provided evidence of extended rearing in the brackish or saltwater regions of the Delta. New advancements in genetics now allow individuals captured by trawls to be assigned to specific runs. Detailed information about movement and survival in the Delta has spurred development of agent-based models of juvenile salmon that are coupled to hydrodynamic models. Although much has been learned, knowledge gaps remain about how very small juvenile salmon (fry and parr) use the Delta. Understanding how all life stages of juvenile salmon grow, rear, and survive in the Delta is critical for devising management strategies that support a diversity of life history strategies.

Conceptual model of sedimentation in the Sacramento-San Joaquin River Delta

Science.gov (United States)

Schoellhamer, David H.; Wright, Scott A.; Drexler, Judith Z.

2012-01-01

Sedimentation in the Sacramento–San Joaquin River Delta builds the Delta landscape, creates benthic and pelagic habitat, and transports sediment-associated contaminants. Here we present a conceptual model of sedimentation that includes submodels for river supply from the watershed to the Delta, regional transport within the Delta and seaward exchange, and local sedimentation in open water and marsh habitats. The model demonstrates feedback loops that affect the Delta ecosystem. Submerged and emergent marsh vegetation act as ecosystem engineers that can create a positive feedback loop by decreasing suspended sediment, increasing water column light, which in turn enables more vegetation. Sea-level rise in open water is partially countered by a negative feedback loop that increases deposition if there is a net decrease in hydrodynamic energy. Manipulation of regional sediment transport is probably the most feasible method to control suspended sediment and thus turbidity. The conceptual model is used to identify information gaps that need to be filled to develop an accurate sediment transport model.

Challenges Facing the Sacramento–San Joaquin Delta: Complex, Chaotic, or Simply Cantankerous?

Directory of Open Access Journals (Sweden)

Samuel N. Luoma

2015-09-01

Full Text Available doi: http://dx.doi.org/10.15447/sfews.2015v13iss3art7Freshwater is a scarce and precious resource in California; its overall value is being made clear by the current severe drought. The Sacramento–San Joaquin Delta is a critical node in a complex water supply system that extends throughout much of the western U.S. wherein demand is exceeding supply. The Delta also underpins a major component of the U.S. economy, helps feed a substantial part of the country, is a unique and valuable ecological resource, and is a place with a rich cultural heritage. Sustaining the Delta is a problem that manifests itself in many dimensions including the physical structure of the Delta, the conflicting demands for water, changing water quality, rapidly evolving ecological character, and high institutional complexity. The problems of the California Delta are increasingly complex, sometimes chaotic, and always contentious. There is general agreement that current management will sustain neither the Delta ecosystem nor high-quality water exports, as required under the Delta Reform Act, so there is a renewed urgency to address all dimensions of the problem aggressively. Sustainable management of the Delta ecosystem and California’s highly variable water supply, in the face of global climate change, will require bold political decisions that include adjustments to the infrastructure but give equal emphasis to chronic overuse and misuse of water, promote enhanced efficiency of water use, and facilitate new initiatives for ecosystem recovery. This new approach will need to be underpinned by collaborative science that supports ongoing evaluation and re-adjustment of actions. Problems like the Delta are formally “wicked" problems that cannot be “solved” in the traditional sense, but they can be managed with appropriate knowledge and flexible institutions. Where possible, it is advisable to approach major actions incrementally, with an eye toward avoiding