7,484 research outputs found
European Corn Borer Parasitoids; Distribution in Southern Minnesota
During the 1940\u27s and 1950\u27s seven exotic parasitoids of the European corn borer (ECB) Ostrinia nubilalis (Hubner), were released in Minnesota. This study was done to determine which introduced parasitoids became established and their distribution in Minnesota. The experiment was conducted during the summer of 1977 and fall of 1977, 78, 79- and 80 in conjunction with the annual ECB population surveys in southern Minnesota by the State Department of Agriculture, Division of Plant Industry. Three introduced parasitoids, Macrocentrus grandii Goidanich, Eriborus Terebrans (Gravenhorst), and Sympiesis viridula (Thomson) and two native parasitoids, lshnus inquisitorius artricollaris (Walsh) and Aplomya caesar (Aldrich) were recovered. M. grandii was confined to the eastern portion, while E. terebrans was recovered from throughout southern Minnesota. S. viridula was found in only three counties, perhaps because of its biology it may have eluded recovery, resulting in underestimated distribution. The two native species, I. inquisitorius atricollaris and A. caesar, occur only occasionally in Minnesota
Auto and cross correlation of phases of the whole-sky CMB and foreground maps from the 1-year WMAP data
The issue of non-Gaussianity is not only related to distinguishing the
theories of the origin of primordial fluctuations, but also crucial for the
determination of cosmological parameters in the framework of inflation
paradigm. We present an advenced method for testing non-Gaussianity on the
whole-sky CMB anisotropies. This method is based on the Kuiper's statistic to
probe the two-dimensional uniformity on a periodic mapping square associating
phases: return mapping of phases of the derived CMB (similar to auto
correlation) and cross correlations between phases of the derived CMB and
foregrounds. Since phases reflect morphology, detection of cross correlation of
phases signifies the contamination of foreground signals in the derived CMB
map. The advantage of this method is that one can cross check the auto and
cross correlation of phases of the derived CMB and foregrounds, and mark off
those multipoles in which the non-Gaussianity results from the foreground
contaminations. We apply this statistic on the derived signals from the 1-year
WMAP data. The auto-correlations of phases from the ILC map shows the
significance above 95% CL against the random phase hypothesis on 17 spherical
harmonic multipoles, among which some have pronounced cross correlations with
the foreground maps. We conclude that most of the non-Gaussianity found in the
derived CMB maps are from foreground contaminations, except, among others, l=6.
With this method we are better equipped to approach the issue of
non-Gaussianity of primordial origin for the upcoming PLANCK mission.Comment: 2 figures added: new representation of reconstructed (from 1D Fourier
composition) DT distribution for each multipole number el
Protein sequence entropy is closely related to packing density and hydrophobicity
We investigated the correlation between the Shannon information entropy, ‘sequence entropy’, with respect to the local flexibility of native globular proteins as described by inverse packing density. These are determined at each residue position for a total set of 130 query proteins, where sequence entropies are calculated from each set of aligned residues. For the accompanying aggregate set of 130 alignments, a strong linear correlation is observed between the calculated sequence entropy and the corresponding inverse packing density determined at an associated residue position. This region of linearity spans the range of Cα packing densities from 12 to 25 amino acids within a sphere of 9 Å radius. Three different hydrophobicity scales all mimic the behavior of the sequence entropies. This confirms the idea that the ability to accommodate mutations is strongly dependent on the available space and on the propensity for each amino acid type to be buried. Future applications of these types of methods may prove useful in identifying both core and flexible residues within a protein
Accuracy of Mesh Based Cosmological Hydrocodes: Tests and Corrections
We perform a variety of tests to determine the numerical resolution of the
cosmological TVD eulerian code developed by Ryu et al (1993). Tests include
512^3 and 256^3 simulations of a Pk=k^{-1} spectrum to check for
self-similarity and comparison of results with those from higher resolution SPH
and grid-based calculations (Frenk et al 1998). We conclude that in regions
where density gradients are not produced by shocks the code degrades resolution
with a Gaussian smoothing (radius) length of 1.7 cells. At shock caused
gradients (for which the code was designed) the smoothing length is 1.1 cells.
Finally, for \beta model fit clusters, we can approximately correct numerical
resolution by the transformation R^2_{core}\to R^2_{core}-(C\Delta l)^2, where
\Delta l is the cell size and C=1.1-1.7. When we use these corrections on our
previously published computations for the SCDM and \Lambda CDM models we find
luminosity weighted, zero redshift, X-ray cluster core radii of (210\pm 86,
280\pm 67)h^{-1}kpc, respectively, which are marginally consistent with
observed (Jones & Forman 1992) values of 50-200h^{-1}kpc. Using the corrected
core radii, the COBE normalized SCDM model predicts the number of bright
L_x>10^{43}erg/s clusters too high by a factor of \sim 20 and the \Lambda CDM
model is consistent with observations.Comment: ApJ in press (1999
Flavor SU(3) symmetry and QCD factorization in and decays
Using flavor SU(3) symmetry, we perform a model-independent analysis of
charmless decays. All the relevant
topological diagrams, including the presumably subleading diagrams, such as the
QCD- and EW-penguin exchange diagrams and flavor-singlet weak annihilation
ones, are introduced. Indeed, the QCD-penguin exchange diagram turns out to be
important in understanding the data for penguin-dominated decay modes. In this
work we make efforts to bridge the (model-independent but less quantitative)
topological diagram or flavor SU(3) approach and the (quantitative but somewhat
model-dependent) QCD factorization (QCDF) approach in these decays, by
explicitly showing how to translate each flavor SU(3) amplitude into the
corresponding terms in the QCDF framework. After estimating each flavor SU(3)
amplitude numerically using QCDF, we discuss various physical consequences,
including SU(3) breaking effects and some useful SU(3) relations among decay
amplitudes of and .Comment: 47 pages, 3 figures, 28 table
Some factors influencing populations of the European corn borer, Ostrinia nubilalis (Hubner) in the north central states: Resistance of corn, time of planting and weather conditions Part II, 1958-1962
A cooperative project was conducted by the agricultural experiment stations of Iowa, Minnesota and Ohio and the U. S. Department of Agriculture to study the effects of weather, planting date and resistant hybrids as factors influencing populations of the European com borer, Ostrinia nubilalis (Hübner). Identical studies were carried out at Ankeny, Iowa; Waseca, Minnesota; and Wooster, Ohio, during a 10-year period, 1953-1962.
The first 4 years of the study (1953-56) were reported by Everett et al. (1958). The work reported herein is a companion bulletin to the Everett et al. (1958) publication and deals with the results of experiments conducted during 1958-1962.
The experimental design was a randomized block, split plot with five replications. The whole plot treatments were four hybrid-planting date combinations consisting of early- or late-planting dates and susceptible or resistant hybrids. The subplot treatments consisted of a factorial arrangement of all possible combinations of three levels of infestation (zero, natural and natural + 3 egg masses) by first brood and the same three levels of infestation by second-brood borers. Temperature and rainfall records were kept at each of the three stations. Borer population and injury to the plant were recorded at the end of the first brood and in the fall. Yield data were collected
Unitary model for the reaction and the magnetic dipole moment of the
Radiative pion photoproduction in the resonance region is
studied with the aim to access the magnetic dipole moment. We
present a unitary model of the () reactions, where the rescattering is included in an on-shell
approximation. In this model, the low energy theorem which couples the process in the limit of a soft final photon to the process is exactly satisfied. We study the sensitivity of the
process at higher values of the final photon
energy to the magnetic dipole moment. We compare our results
with existing data and give predictions for forthcoming measurements of angular
and energy distributions. It is found that the photon asymmetry and a helicity
cross section are particularly sensitive to the magnetic dipole
moment.Comment: 23 pages, 18 figure
Population history from the Neolithic to present on the Mediterranean island of Sardinia: an ancient DNA perspective
Recent ancient DNA studies of western Eurasia have revealed a dynamic history of admixture, with evidence for major migrations during the Neolithic and Bronze Age. The population of the Mediterranean island of Sardinia has been notable in these studies –} Neolithic individuals from mainland Europe cluster more closely with Sardinian individuals than with all other present-day Europeans. The current model to explain this result is that Sardinia received an initial influx of Neolithic ancestry and then remained relatively isolated from expansions in the later Neolithic and Bronze Age that took place in continental Europe. To test this model, we generated genome-wide capture data (approximately 1.2 million variants) for 43 ancient Sardinian individuals spanning the Neolithic through the Bronze Age, including individuals from Sardinia{’}s Nuragic culture, which is known for the construction of numerous large stone towers throughout the island. We analyze these new samples in the context of previously generated genome-wide ancient DNA data from 972 ancient individuals across western Eurasia and whole-genome sequence data from approximately 1,500 modern individuals from Sardinia. The ancient Sardinian individuals show a strong affinity to western Mediterranean Neolithic populations and we infer a high degree of genetic continuity on the island from the Neolithic (around fifth millennium BCE) through the Nuragic period (second millennium BCE). In particular, during the Bronze Age in Sardinia, we do not find significant levels of the {“}Steppe{” ancestry that was spreading in many other parts of Europe at that time. We also characterize subsequent genetic influx between the Nuragic period and the present. We detect novel, modest signals of admixture between 1,000 BCE and present-day, from ancestry sources in the eastern and northern Mediterranean. Within Sardinia, we confirm that populations from the more geographically isolated mountainous provinces have experienced elevated levels of genetic drift and that northern and southwestern regions of the island received more gene flow from outside Sardinia. Overall, our genetic analysis sheds new light on the origin of Neolithic settlement on Sardinia, reinforces models of genetic continuity on the island, and provides enhanced power to detect post-Bronze-Age gene flow. Together, these findings offer a refined demographic model for future medical genetic studies in Sardinia
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