2,872 research outputs found
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Issues related to direct seeding of rice in rainfed cropping systems in northwest Bangladesh
Economic factors and developments in rice production technologies are the major drivers that have led to the adoption of direct seeding of rice in place of transplanting in Asia. The primary economic motives for a shift to direct seeding are the savings in labor cost and the possibility of crop intensification. A key development challenge in the drought-prone rainfed agriculture of the Barind Tract of northwest Bangladesh is to simultaneously improve the reliability and yield of monsoon rice while improving total system productivity by increasing the area planted to drought-tolerant postrice crops. Research trials and field-scale evaluation by farmers have demonstrated that dry direct seeding or wet seeding of pregerminated
rice seed reduces labor for crop establishment, results in rice yields similar to or higher than those from conventional transplanting, and advances harvest by
7-10 days. Earlier harvest has the potential to reduce the risk of terminal drought in rice when the monsoon ends abruptly and increases the opportunity for establishing
a postrice crop of chickpea on residual moisture. Herbicide use is essential with direct seeding and this further reduces rice production costs. This modified
rice/legume system using direct seeding is knowledge-intensive. Widespread sustained adoption will depend on farmers undertaking timely tillage, adequate land
leveling, and timely application of herbicides. Extension/farmer training supported by clear decision support frameworks will be needed to provide farmers with access to the knowledge needed to implement direct seeding effectively
Probing Small-Molecule Microarrays with Tagged Proteins in Cell Lysates
The technique of small-molecule microarray (SMM) screening is based on the ability of small molecules to bind to various soluble proteins. This type of interaction is easily detected by the presence of a fluorescence signal produced by labeled antibodies that specifically recognize a unique sequence (tag) present on the target protein. The fluorescent signal intensity values are determined based on signal-to-noise ratios (SNRs). SMM screening is a high-throughput, unbiased method that can rapidly identify novel direct ligands for various protein targets. This binding-based assay format is generally applicable to most proteins, but it is especially useful for protein targets that do not possess an enzymatic activity. SMMs enable screening a protein in a purified form or in the context of a cellular lysate, likely providing a more physiologically relevant screening environment.National Cancer Institute (U.S.) (CA160860
Objective pilling evaluation of wool fabrics
An objective pilling evaluation method based on the multi-scale two-dimensional dual-tree complex wavelet transform and linear discriminant function of Bayes\u27 Rule was developed. The surface fuzz and pills are identified from the high-frequency noise, fabric textures, fabric surface unevenness, and illuminative variation of a pilled fabric image by the two-dimensional dual-tree complex wavelet decomposition and reconstruction. The energies of the reconstructed subimages in six spatial orientations (±15º, ±45º, ±75º) are calculated as the elements of the pilling feature vector, whose dimension is reduced by principal component analysis. A linear discriminant function of Bayes\u27 Rule was used as a classifier to establish classification rules among the five pilling grades. A new pilled sample with the same physical construction can then be automatically assigned to one of the five pilling grades by the classification rules. A general evaluation of the proposed method was conducted using the SM50 woven, non-woven, and SM54 knitted standard pilling test image sets. The results suggest that the new method can successfully establish classification rules among the five pilling grade groups for each of the three standard pilling test image sets and should be applicable to practical objective pilling evaluation
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Precipitation and latent heating distributions from satellite passive microwave radiometry. Part I: improved method and uncertainties
A revised Bayesian algorithm for estimating surface rain rate, convective rain proportion, and latent heating profiles from satellite-borne passive microwave radiometer observations over ocean backgrounds is described. The algorithm searches a large database of cloud-radiative model simulations to find cloud profiles that are radiatively consistent with a given set of microwave radiance measurements. The properties of these radiatively consistent profiles are then composited to obtain best estimates of the observed properties. The revised algorithm is supported by an expanded and more physically consistent database of cloud-radiative model simulations. The algorithm also features a better quantification of the convective and nonconvective contributions to total rainfall, a new geographic database, and an improved representation of background radiances in rain-free regions. Bias and random error estimates are derived from applications of the algorithm to synthetic radiance data, based upon a subset of cloud-resolving model simulations, and from the Bayesian formulation itself. Synthetic rain-rate and latent heating estimates exhibit a trend of high (low) bias for low (high) retrieved values. The Bayesian estimates of random error are propagated to represent errors at coarser time and space resolutions, based upon applications of the algorithm to TRMM Microwave Imager (TMI) data. Errors in TMI instantaneous rain-rate estimates at 0.5°-resolution range from approximately 50% at 1 mm hâ1 to 20% at 14 mm hâ1. Errors in collocated spaceborne radar rain-rate estimates are roughly 50%â80% of the TMI errors at this resolution. The estimated algorithm random error in TMI rain rates at monthly, 2.5° resolution is relatively small (less than 6% at 5 mm dayâ1) in comparison with the random error resulting from infrequent satellite temporal sampling (8%â35% at the same rain rate). Percentage errors resulting from sampling decrease with increasing rain rate, and sampling errors in latent heating rates follow the same trend. Averaging over 3 months reduces sampling errors in rain rates to 6%â15% at 5 mm dayâ1, with proportionate reductions in latent heating sampling errors
Cholinergic efferent synaptic transmission regulates the maturation of auditory hair cell ribbon synapses.
Spontaneous electrical activity generated by developing sensory cells and neurons is crucial for the maturation of neural circuits. The full maturation of mammalian auditory inner hair cells (IHCs) depends on patterns of spontaneous action potentials during a 'critical period' of development. The intrinsic spiking activity of IHCs can be modulated by inhibitory input from cholinergic efferent fibres descending from the brainstem, which transiently innervate immature IHCs. However, it remains unknown whether this transient efferent input to developing IHCs is required for their functional maturation. We used a mouse model that lacks the α9-nicotinic acetylcholine receptor subunit (α9nAChR) in IHCs and another lacking synaptotagmin-2 in the efferent terminals to remove or reduce efferent input to IHCs, respectively. We found that the efferent system is required for the developmental linearization of the Ca(2+)-sensitivity of vesicle fusion at IHC ribbon synapses, without affecting their general cell development. This provides the first direct evidence that the efferent system, by modulating IHC electrical activity, is required for the maturation of the IHC synaptic machinery. The central control of sensory cell development is unique among sensory systems
Combined effect of coherent Z exchange and the hyperfine interaction in atomic PNC
The nuclear spin-dependent parity nonconserving (PNC) interaction arising
from a combination of the hyperfine interaction and the coherent,
spin-independent, PNC interaction from Z exchange is evaluated using many-body
perturbation theory. For the 6s-7s transition in 133Cs, we obtain a result that
is about 40% smaller than that found previously by Bouchiat and Piketty [Phys.
Lett. B 269, 195 (1991)]. Applying this result to 133Cs, leads to an increase
in the experimental value of nuclear anapole moment and exacerbates differences
between constraints on PNC meson coupling constants obtained from the Cs
anapole moment and those obtained from other nuclear parity violating
experiments. Nuclear spin-dependent PNC dipole matrix elements, including
contributions from the combined weak-hyperfine interaction, are also given for
the 7s-8s transition in 211Fr and for transitions between ground-state
hyperfine levels in K, Rb, Cs, Ba+, Au, Tl, Fr, and Ra+.Comment: Revtex4 preprint 19 pages 4 table
Differences in location and electrophyslologic properties of atrial tachycardias in structurally normal and abnormal hearts
Kappa symmetric OSp(2|2) WZNW model
We construct a kappa symmetric WZNW model for the OSp(2|2) supergroup, whose
bosonic part is AdS3xS1 space. The field equation gives the chiral current
conservation and the right/left factorization is shown after the kappa symmetry
is fixed. The right-moving modes contain both bosons and fermions while the
left-moving modes contain only bosons.Comment: 18 pages; reference and comments added, version to appear in JHE
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