11,088 research outputs found
Tillering Response of \u27Monon\u27 And \u27Newton\u27 Winter Wheats Infested With Biotype L Hessian Fly (Diptera: Cecidomyiidae) Larvae
Two wheat, Triticum aestivum, cultivars that differed in their ability to tiller were infested by ovipositing Hessian flies, Mayetiola destructor, under similar controlled conditions. Since a larva typically stunts and kills the stem where it feeds and develops, tiller development of fly infested-wheat seedlings is an important plant trait relative to grain yield. \u27Monon\u27 tillered more than \u27Newton at the 0 infestation level (control). \u27Monon\u27 had about the same number of tillers at 0, 1, 2, and 3 puparia (indicative of the number of feeding larvae) per plant; and \u27Newton\u27 had fewer tillers at 0 than 1, 2, or 3 puparia per stem. However, tillering of both cultivars was less at 4 or more puparia per stem, perhaps due to the depletion of plant nutrients. In general, for both cultivars there was a decrease in leaf length, number and wet weight as the number of puparia increased per tiller
Electroantennogram Responses of the Armyworm (Lepidoptera: Noctuidae) and Cereal Leaf Beetle (Coleoptera: Chrysomelidae) to Volatile Chemicals of Seedling Oats
Armyworm, Pseudaletia unipuncta, eIectroantennogram (EAG) responses to 10 volatile chemicals of seedling oats and three of injured green plants were significantly different from each other while cereal leaf beetle, Oulema melallopus, EAG responses were not significantly different. The EAG responses of both species did not vary significantly with respect to sex, age, or between the antennae of the same specimen. (E)-2-hexenol, a compound extracted from injured green plants, yielded the highest peak response for the armyworm while more cereal leaf beetle antennae responded to this chemical than any other chemical. Armyworm antennallife averaged 38 + 20 min while those of the cereal leaf beetle averaged 6 + 14 min
Some Combinatorial Properties of Hook Lengths, Contents, and Parts of Partitions
This paper proves a generalization of a conjecture of Guoniu Han, inspired
originally by an identity of Nekrasov and Okounkov. The main result states that
certain sums over partitions p of n, involving symmetric functions of the
squares of the hook lengths of p, are polynomial functions of n. A similar
result is obtained for symmetric functions of the contents and shifted parts of
n.Comment: 20 pages. Correction of some inaccuracies, and a new Theorem 4.
Three osculating walkers
We consider three directed walkers on the square lattice, which move
simultaneously at each tick of a clock and never cross. Their trajectories form
a non-crossing configuration of walks. This configuration is said to be
osculating if the walkers never share an edge, and vicious (or:
non-intersecting) if they never meet. We give a closed form expression for the
generating function of osculating configurations starting from prescribed
points. This generating function turns out to be algebraic. We also relate the
enumeration of osculating configurations with prescribed starting and ending
points to the (better understood) enumeration of non-intersecting
configurations. Our method is based on a step by step decomposition of
osculating configurations, and on the solution of the functional equation
provided by this decomposition
Storage and Behavior of Plant and Diet-Fed Adult Cereal Leaf Beetle, Oulema Melanopus (Coleoptera: Chrysomelidae)
The univoltine life cycle of the cereal leaf beetle Oulema melanopus (L.) in Michigan (Castro et al. 1965) is similar to that reported by Venturi (1942) in Europe. Adults emerge from pupal cells in the soil in mid-June to early July, feed voraciously for about three weeks, and enter aestivation sites. For the remainder of the summer and early autumn only a few adults can be found feeding on late-maturing native grasses. The beetles overwinter and usually emerge in late March to early April and resume feeding. Mating and oviposition occur, and larval development is usually completed by late June in southern Michigan.
Techniques for rearing the cereal leaf beetle on greenhouse-grown small grain seedlings have been developed by Connin, et al. (1968). Maintaining these cultures requires collecting field adults, growing host material, and handling the cultures to insure that all stages will be available for study.
In Michigan during July adults can be collected more economically and in greater numbers in the field than by rearing in the laboratory. A summary of collection techniques, laboratory feeding and storage conditions for large numbers of field-collected cereal leaf beetles is presented in this paper. In addition, the mortality during storage of newly emerged field collected beetles fed either barley seedlings or an artificial diet is compared
Hadron Spin Dynamics
Spin effects in exclusive and inclusive reactions provide an essential new
dimension for testing QCD and unraveling hadron structure. Remarkable new
experiments from SLAC, HERMES (DESY), and the Jefferson Laboratory present many
challenges to theory, including measurements at HERMES and SMC of the single
spin asymmetries in pion electroproduction, where the proton is polarized
normal to the scattering plane. This type of single spin asymmetry may be due
to the effects of rescattering of the outgoing quark on the spectators of the
target proton, an effect usually neglected in conventional QCD analyses. Many
aspects of spin, such as single-spin asymmetries and baryon magnetic moments
are sensitive to the dynamics of hadrons at the amplitude level, rather than
probability distributions. I illustrate the novel features of spin dynamics for
relativistic systems by examining the explicit form of the light-front
wavefunctions for the two-particle Fock state of the electron in QED, thus
connecting the Schwinger anomalous magnetic moment to the spin and orbital
momentum carried by its Fock state constituents and providing a transparent
basis for understanding the structure of relativistic composite systems and
their matrix elements in hadronic physics. I also present a survey of
outstanding spin puzzles in QCD, particularly the double transverse spin
asymmetry A_{NN} in elastic proton-proton scattering, the J/psi to rho-pi
puzzle, and J/psi polarization at the Tevatron.Comment: Concluding theory talk presented at SPIN2001, the Third
Circum-Pan-Pacific Symposium on High Energy Physics, October, 2001, Beijin
The Pathophysiology of Chronic Relapsing Experimental Allergic Encephalomyelitis in the Lewis Rat
Electrophysiological studies were performed in Lewis rats with chronic relapsing experimental allergic encephalomyelitis (EAE) induced by inoculation with guinea-pig spinal cord and adjuvants and treatment with low dose cyclosporin A. During clinical episodes there was conduction failure in the central nervous system (CNS), namely the spinal cord dorsal columns, and in the afferent fibres in the peripheral nervous system (PNS). The following observations indicated that the conduction failure was mainly due to demyelination-induced conduction block: (1) rate-dependent conduction block in the CNS and PNS; (2) temporal dispersion due to slowing of PNS conduction; (3) restoration of PNS conduction by cooling; (4) restoration of CNS conduction by ouabain; (5) previously demonstrated histological evidence of primary demyelination in the dorsal columns, dorsal root ganglia and dorsal roots; and (6) the temporal association of restoration of conduction with remyelination. However, it is likely that CNS and PNS axonal degeneration, which occurs in this disease, also contributed to the conduction failure. In clinical remissions there was restoration of conduction in the CNS and PNS which can be explained by ensheathment/remyelination by oligodendrocytes and Schwann cells, respectively. In most rats during clinical episodes the cerebral somatosensory evoked potential was reduced in amplitude and prolonged in latency, which can be accounted for by demyelination and axonal degeneration in the CNS and PNS components of the afferent pathway. In 2 rats with episodes of EAE, however, this potential was markedly increased in amplitude, which might have been due to demyelination-induced conduction block of descending pathways that normally inhibit synaptic transmission in the afferent pathway. In well-established remission there was residual conduction failure in the CNS and PNS which can be mainly accounted for by axonal degeneration
Relation between the High Density Phase and the Very-High Density Phase of Amorphous Solid Water
It has been suggested that high-density amorphous (HDA) ice is a structurally
arrested form of high-density liquid (HDL) water, while low-density amorphous
(LDA) ice is a structurally arrested form of low-density liquid (LDL) water.
Recent experiments and simulations have been interpreted to support the
possibility of a second "distinct" high-density structural state, named very
high-density amorphous (VHDA) ice, questioning the LDL-HDL hypothesis. We test
this interpretation using extensive computer simulations, and find that VHDA is
a more stable form of HDA and that in fact VHDA should be considered as the
amorphous ice of the quenched HDL.Comment: 5 pages, 4 fig
Classification of GHZ-type, W-type and GHZ-W-type multiqubit entanglements
We propose the concept of SLOCC-equivalent basis (SEB) in the multiqubit
space. In particular, two special SEBs, the GHZ-type and the W-type basis are
introduced. They can make up a more general family of multiqubit states, the
GHZ-W-type states, which is a useful kind of entanglement for quantum
teleporatation and error correction. We completely characterize the property of
this type of states, and mainly classify the GHZ-type states and the W-type
states in a regular way, which is related to the enumerative combinatorics.
Many concrete examples are given to exhibit how our method is used for the
classification of these entangled states.Comment: 16 pages, Revte
Mean-field calculation of critical parameters and log-periodic characterization of an aperiodic-modulated model
We employ a mean-field approximation to study the Ising model with aperiodic
modulation of its interactions in one spatial direction. Two different values
for the exchange constant, and , are present, according to the
Fibonacci sequence. We calculated the pseudo-critical temperatures for finite
systems and extrapolate them to the thermodynamic limit. We explicitly obtain
the exponents , , and and, from the usual scaling
relations for anisotropic models at the upper critical dimension (assumed to be
4 for the model we treat), we calculate , , , ,
and . Within the framework of a renormalization-group approach, the
Fibonacci sequence is a marginal one and we obtain exponents which depend on
the ratio , as expected. But the scaling relation is obeyed for all values of we studied. We characterize
some thermodynamic functions as log-periodic functions of their arguments, as
expected for aperiodic-modulated models, and obtain precise values for the
exponents from this characterization.Comment: 17 pages, including 9 figures, to appear in Phys. Rev.
- …