Rotational Sequences Research Articles

Effect of Spring Tillage Sequence on Summer Annual Weeds in Vegetable Row Crop Rotations

The effects of spring tillage sequence on summer annual weed populations were evaluated over two cycles of a 3-yr crop rotation of snap beans, sweet corn, and winter wheat. Continuous no-till (N) planting of vegetable crops each spring (NNNN) reduced summer annual weed density 63 to 86% compared to that of continuous conventional tillage (CCCC), depending upon site and herbicide level. Hairy nightshade populations were reduced by 88 to 96% when spring tillage was eliminated from the crop rotation. The effects of the NNNN spring tillage sequence on weed density were similar at two sites even though the crop rotations at the two sites began with different crops. The rotational tillage sequence of NCNC at the East site, in a crop rotation that began with corn, reduced summer annual weed density by 46 to 51% compared to that of continuous conventional tillage and planting (CCCC) at low and medium herbicide rates, respectively. In contrast, the tillage sequence of CNCN in the same crop rotation and at the same site increased weed density by 80% compared to that of CCCC at a low herbicide rate. The effects of the NCNC and CNCN rotational tillage sequences on weed density were reversed at the West site, and was probably caused by pairing sweet corn with conventional tillage rather than no tillage. The reduction in summer annual weed density caused by reduced spring tillage frequency did not significantly increase crop yields.

High spin studies of the Er and Tm isotopes around A= 166

Fusion and incomplete fusion evaporation channels were studied in the 7Li +164Dy reaction at the INFN Laboratory, Legnaro, Italy. The Tandem-XTU accelerator was used to accelerate a beam of 7Li ions to 55 MeV. The highly sensitive GASP γ-detector array coupled with the selectivity of the ISIS charged particle ΔE–E telescope array provided a powerful tool for studies of high spin states in the fusion and incomplete fusion reaction products. Rotational sequences in the Er and Tm isotopes around A = 166 have been observed and extended to higher spin states. Comparisons of the experimental data with the results of the cranked shell model give some insight into the configuration dependence of the crossing of the ground-state band with the aligned i13/2 two quasineutron configuration.

Standardized volume-rendering of contrast-enhanced renal magnetic resonance angiography

To propose a technique for standardizing volume-rendering technique (VRT) protocols and to compare this with maximum intensity projection (MIP) in regard to image quality and diagnostic confidence in stenosis diagnosis with magnetic resonance angiography (MRA). Twenty patients were examined with MRA under suspicion of renal artery stenosis. Using the histogram function in the volume-rendering software, the 95th and 99th percentiles of the 3D data set were identified and used to define the VRT transfer function. Two radiologists assessed the stenosis pathology and image quality from rotational sequences of MIP and VRT images. Good overall agreement (mean kappa=0.72) was found between MIP and VRT diagnoses. The agreement between MIP and VRT was considerably better than that between observers (mean kappa=0.43). One of the observers judged VRT images as having higher image quality than MIP images. Presenting renal MRA images with VRT gave results in good agreement with MIP. With VRT protocols defined from the histogram of the image, the lack of an absolute gray scale in MRI need not be a major problem.

The Exploitation of Crop Allelopathy in Sustainable Agricultural Production

AbstractCrop allelopathy may be useful to minimize serious problems in the present agricultural production such as environmental pollution, unsafe products, human health concerns, depletion of crop diversity, soil sickness and reduction of crop productivity. Several crops including alfalfa, buckwheat, maize, rice, rye, sorghum, sunflower, wheat, etc. are affected either by their own toxicity or phytotoxin exudates when their residues decompose in the soil, that show strong suppression on weed emergences. Allelopathic crops when used as cover crop, mulch, smother crops, green manures, or grown in rotational sequences are helpful in reducing noxious weeds and plant pathogen, improve soil quality and crop yield. Those crop plants, particularly the legumes, incorporated at 1–2 tons ha−1 (alfalfa, buckwheat, rice by‐products), which can give weed reduction and increase of rice yield by 70 and 20 %, respectively, are suggested for use as natural herbicides. Allelochemicals from allelopathic crops may aid in the development of biological herbicides and pesticides. Cultivating a system with allelopathic crops plays an important role in the establishment of sustainable agriculture. The introduction of allelopathic traits from accessions with strong allelopathic potential to the target crops will enhance the efficacy of crop allelopathy in future agricultural production.

WE‐C‐I‐611‐01: Basic System Design and Application

The use of real‐time or rapid sequence x‐ray imaging has been increasing. Not only are the GI and cardiology applications to diagnostic procedures of continuing interest, but new image guided interventional procedures are being developed which rely on the combination of high spatial and temporal resolution x‐ray imaging. In particular, rotational angiographic sequences combined with cone‐beam computed tomography have enabled advances in minimally invasive endovascular interventional procedures to often replace invasive surgical procedures. In this symposium, after a review of some of the clinical applications of dynamic x‐ray imaging including fluoroscopy and angiography, we will discuss some of the unique problems associated with image quality evaluation for such total x‐ray imaging systems, as well as review some of the new developments in detector design with a comparison of flat panel and image intensifier‐based systems. Also we will discuss developments in cone‐beam computed tomography with specific application to angiography and ultimately to the potential for changing the treatment paradigm for vascular disease through the combination of computerized blood flow analysis and angiographic image guided interventions.Educational Objectives:1. To appreciate the widening clinical application of dynamic x‐ray imaging to diagnostic and interventions.2. To indicate the quality evaluation issues in total x‐ray imaging systems as well as the new developments of digital detectors and cone‐beam computed tomography.(Partial support: NIH Grants R01EB002873 and R01NS43924, Toshiba Medical Systems Corp., UB Foundation, UB‐STOR, Guidant Corp.).

Planar and aplanar tilted bands in the odd–odd nucleus 132Cs

High-spin states in the doubly odd N = 77 nucleus 132Cs have been studied. Gamma-ray linear polarization and angular correlation measurements have been performed to determine the spin and parity of the states. A rotational sequence of enhanced dipole transitions was established. This band can be described within the framework of the the tilted axis cranking (TAC) model as a band based on a weakly deformed structure in which the total angular momentum vector does not coincide with any of the principal axes of the triaxial nucleus but still is in the plane defined by the short and long axes. The theoretical description of the previously proposed chiral bands in 132Cs was extended in the framework of the core–particle coupling model (CPCM) confirming that the total angular momentum for the πh11/2 ⊗ νh11/2 configuration is well outside any planes defined by the principal axes of the nucleus and revealing the important role of the residual proton–neutron interaction between the valence particles.

Multispecies resistance and integrated management: a bioeconomic model for integrated management of rigid ryegrass (Lolium rigidum) and wild radish (Raphanus raphanistrum)

Rigid ryegrass and wild radish dominate and coexist throughout southern Australian dryland cropping regions. Widespread herbicide resistance in these species has led to adoption of diverse and complex integrated weed management practices, which require evaluation of their impact on farming systems. Therefore, a multispecies version of the bioeconomic model resistance and integrated management (RIM) has been developed to compare long-term economic and weed population outcomes of various integrated management scenarios. We have extended the original single-species ryegrass RIM model to include wild radish biology and additional weed management practices used to control this species. The multispecies model can be used to evaluate weed management scenarios for coexisting herbicide-resistant species by investigating the implications of different crop–pasture rotational sequences and of varying herbicide availability. Multispecies RIM shows that economic differences between the scenarios are not due to differences in weed densities but to differences in total weed control costs.

RIM: a bioeconomic model for integrated weed management of Lolium rigidum in Western Australia

The RIM (resistance and integrated management) model is presented. RIM represents a wide diversity of herbicide and non-herbicide options for management of Australia's most important crop weed, Lolium rigidum, in the context of the non-irrigated extensive farming system of southern Australia. Enterprise choices in the model include cereals, lupins, canola and three types of pastures for grazing by sheep. Users of RIM may specify the enterprise sequence and any feasible combination of the 35 weed treatment options each year over 10 or 20 years. Weed treatment options include selective herbicides (11), non-selective herbicides (5), non-chemical treatments (16) and user-defined treatments (3). The model represents weed and seed bank population dynamics, weed-crop competition, weed treatment impacts (including phytotoxicity), agronomic details, and financial details. Economic and biological model results are presented for scenarios with differing levels of availability of selective herbicides and different rotational sequences.

Rotational band structures inN=89153Gd

The reactions ${}^{152}\mathrm{Sm}(\ensuremath{\alpha},3n)$ at 37 MeV and ${}^{124}\mathrm{Sn}{(}^{36}\mathrm{S},\ensuremath{\alpha}3n)$ at 165 MeV were used to produce high-spin states in the transitional rare-earth nucleus ${}^{153}\mathrm{Gd}.$ Significant extensions in angular momentum and excitation energy with respect to earlier work were achieved and several new rotational sequences were observed. The rotational behavior of ${}^{153}\mathrm{Gd}$ is described in terms of quasiparticle assignments and the observed alignment properties are analyzed within the framework of the cranked shell model. Detailed comparisons with other $N=89$ nuclei are presented. These have led to corrections to the ${}^{157}\mathrm{Er}$ level scheme.

Rotational Sequences of Global Oscillations inside the Sun

A very simple mathematical sequence is detected in a half-century of thermal radio flux from the Sun. Since the only known solar source for the sequence is global oscillations trapped in the nonconvecting interior, g-modes and probably r-modes are active. If so, their rotation frequencies are detected and some previously reported difference frequencies are confirmed with high confidence. All angular harmonics for 2 ≤ l ≤ 7 are detected as well as some others up to the limit l ≤ 14 resolvable by the observations (a Fourier spectrum of the 10.7 cm flux time series). The mean sidereal rotation rate of the nonconvecting interior is 428.2 nHz as averaged by g-modes and 429.8 nHz by the r-modes, indicating that g-mode energy is a bit more centrally concentrated. Helioseismology measures such rotation rates near 0.36R (R = solar radius), so the global modes would have about half their kinetic energy above and below that level. This, and the known log (r) energy dependence of most modes, implies that these oscillations are significantly reflected near 0.18R, the same level at which sound speed measurements display a maximum departure from theoretical models.

Tilted dipole bands in123Xe

High-spin states in ${}^{123}\mathrm{Xe}$ were populated in $\mathrm{the}{ }^{110}\mathrm{Pd}{(}^{18}\mathrm{O},5n)$ reaction at 75 MeV and gamma-ray coincidences were measured with the GASP spectrometer. A new rotational sequence of enhanced dipole transitions was established. This band, as well as a similar band $\mathrm{in}{ }^{124}\mathrm{Xe},$ may be described within the framework of the tilted axis cranking model as bands for which comparable amounts of angular momentum are generated by magnetic and collective rotation, respectively.

Temporally resolved species measurements in a flickering AIR-diluted, non-premixed natural gas flame by extractive sampling of flame gases and fourier transform ir analysis

Spatially and temporally resolved concentrations of carbon monoxide, carbon dioxide, methane, andacetylene are presented for a 10 Hz, acoustically forced, air-diluted natural gas flame with a fuel mixture equivalence ratio of 3.3. Samples were withdrawn from the flame using a modified quartz microprobe designed to minimize dead volume in the probe during the sampling event. Valve opening and closing were synchronized to the forcing waveform. Extracted gases were analyzed using on-line Fourier transform IR spectrometry. Concentrations were determined using a combination of singular value decomposition matrix techniques and fitting of rotational line sequences. In both techniques, samples were calibrated using data collected in a well-characterized methane/air diffusion flame supported on a Wolfhard-Parker slot burner. Because these four species comprise most of the carbon in the flame, their concentrations can be used to estimate the mass fraction of carbon and thus mixture fraction. Contour maps of all four species and mixture fraction are presented.

Signature inversion in the yrast band of164Ta

Excited states in Ta-164 were populated in the Nd-142(Al-27,5n)Ta-164 reaction and investigated using the AFRODITE spectrometer Arran. The yrast rotational decay sequence Lip to spin 21(-) is identified for the first time and assigned to the pi[514]9/2(-) x nu[660]1/2(+) configuration. A less intense. excited hand is also identified. Low-spin signature inversion is observed in the yrast band, and is compared with the extended total Routhian surface calculations. It is likely that quadrupole pairing plays a role in generating the anomalous signature splitting, but an additional mechanism apart front the assumed mean field and quadrupole pairing interaction may be required to account for the experimental data.

Rotational echo double resonance in ISN spin networks: Deconvolution of multiple dipole–dipole couplings

In a recent paper we have demonstrated how a simple modification to the standard rotational echo double resonance pulse sequence, where the flip angle of the pulse applied to the S spin is varied, can be used to separate the measurement of the magnitude of I–S dipole–dipole couplings from that of their relative orientation. An equivalent result can be achieved via phase modulation which labels and differentiates between different evolving coherences in the density matrix based on the number of S spins participating—exactly as is done in multiple quantum spectroscopy. As phase modulation can be effected on modern instruments with much higher precision, in this paper we explore the experimental implementation of this method in the IS2 spin system glycine–C213–N15, and discuss generalizations of this technique to larger spin systems.

Nuclear structure studies at Saha Institute of Nuclear Pysics using gamma detector arrays

In-beam gamma-ray spectroscopy, carried out at the Saha Institute of Nuclear Physics in the recent past, using heavy-ion projectiles from the pelletron accelerator centres in the country and multi-detector arrays have yielded significant data on the structure of a large number of nuclei spanning different mass regions. The experiments included the study of two-fold γγ-coincidence events for establishing decay schemes, directional correlation of oriented nuclei (DCO) for help in spin assignments and Doppler shift attenuation for lifetime information. The studies have led to the observation of rotational sequences of states in nuclei near closed shell in the mass A=110 region, vibrational spectra in nuclei with A ∼ 60, interplay between single-particle and collective modes of excitation in the doubly-odd bromine isotopes, decoupled bands with large quadrupole deformation in 77Br, shape transition with rotational frequency within a band in 135Pm and octupole collectivity in 153Eu. Particle-rotor-model and cranked-shell-model calculations have been carried out to provide an understanding of the underlying nuclear structure.

Modified vector rotational CORDIC (MVR-CORDIC) algorithm and architecture

The CORDIC algorithm is a well-known iterative method for the computation of vector rotation. However, the major disadvantage is its relatively slow computational speed. For applications that require forward rotation (or vector rotation) only, we propose a new scheme, the modified vector rotational CORDIC (MVR-CORDIC) algorithm, to improve the speed performance of CORDIC algorithm. The basic idea of the proposed scheme is to reduce the iteration number directly while maintaining the SQNR performance. This can be achieved by modifying the basic microrotation procedure of CORDIC algorithm. Meanwhile, three searching algorithms are suggested to find the corresponding directional and rotational sequences so as to obtain the best SQNR performance. Three SQNR performance refinement schemes are also suggested in this paper. Namely, the selective prerotation scheme, selective scaling scheme, and iteration-tradeoff scheme. They can reduce and balance the quantization errors encountered in both microrotation and scaling phases so as to further improve the overall SQNR performance. Then, by combining these three refinement schemes, we provide a systematic design flow as well as the optimization procedure in the application of MVR-CORDIC algorithm. Finally, we present two VLSI architectures for the MVR-CORDIC algorithm. It shows that by using the proposed MVR-CORDIC algorithm, we can save 50% execution time in the iterative CORDIC structure, or 50% hardware complexity in the parallel CORDIC structure compared with the conventional CORDIC scheme.

Band crossing and signature splitting in odd mass [formula omitted] shell nuclei

Structure of two sets of mirror nuclei: 47 V– 47 Cr and 49 Cr– 49 Mn, as well as 49 V and 51 Mn, is studied using the projected shell model. Their yrast spectra are described as an interplay between the angular momentum projected states around the Fermi level which carry different intrinsic K-quantum numbers. The deviations from a regular rotational sequence are attributed to band crossing and signature splitting, which are usually discussed in heavy nuclear systems. Our results agree reasonably with experimental data, and are comparable with those from the full pf shell model calculations.

Rotational bands near 56Ni

Rotational bands have been found in Co-57 and Ni-57, using Gammasphere in conjunction with the Microball and 30 neutron detectors. The bands in Co-57, extending the mass 60 region of deformation down to Z = 27, are signature partner sequences. The quadrupole moments and dynamic moments of inertia of the new bands in both nuclei are similar to those of rotational sequences in the neighboring nuclei. The high-spin structure of Co-57 is compared with Skyrme Hartree-Fock calculations.

Signature splitting and quasiparticle alignment in the yrast band of165Ta

Excited states in ${}^{165}\mathrm{Ta}$ were populated in the ${}^{142}\mathrm{Nd}{(}^{27}\mathrm{Al}{,4n)}^{165}\mathrm{Ta}$ and ${}^{141}\mathrm{Pr}{(}^{28}\mathrm{Si}{,4n)}^{165}\mathrm{Ta}$ reactions and investigated using the AFRODITE array. The yrast rotational decay sequence up to spin ${53/2}^{\ensuremath{-}}$ is identified and assigned to the $[514]{9/2}^{\ensuremath{-}}$ configuration. The nuclear shape is investigated using total Routhian surface calculations. The experimental results are discussed in relation to existing data in the neighboring Ta isotopes and results from cranked shell model calculations. Unexpectedly large signature splitting, for a high-$\ensuremath{\Omega}$ configuration, is observed in the yrast band. Further discrepancies are observed between theoretical and experimental values for the band crossing frequency and signature splitting of the $B(M1)/B(E2)$ ratios. The possibility that these discrepancies are a consequence of a large deviation from an axially symmetric nuclear shape is investigated.

Detailed Spectroscopy in the Superdeformed Second Minimum of 240 Pu

Spectroscopic studies in the superdeformed shape isomer of 240Pu using γ-spectroscopy, conversion electron spectroscopy and transmission resonance spectroscopy have been performed. In a high-resolution and high-efficiency γ-spectroscopy experiment the out-of-band decays of several excited superdeformed rotational sequences with K=2− and 1− could be identified together with evidence for a weakly populated 0− octupole band. Surprisingly, no low-lying collective quadrupole excitations could be observed. Complementary information could be obtained in conversion electron measurements in coincidence with isomeric fission, resulting in the first identification of the lowest s-vibrational K=0+ band. For all rotational bands the variation of the moment of inertia with spin could be studied. A predominant population of negative parity states in the second well could be observed, which can be explained by the selective population and depopulation of the second minimum. Complementary transmission resonance measurements have been performed, yielding new information on the fine structure of high-lying (s-)vibrational multi-phonon states. A new method could be established to determine the excitation energy of the fission isomer ground state from measured level densities.