1,172 research outputs found
Identification of Heterorhabditis (Nematoda : Heterorhabditidae) from California with a new species isolated from the larvae of the ghost moth Hepialis californicus (Lepidoptera : Hepialidae) from the Bodega Bay Natural Reserve
Les mĂ©thodes de taxonomie classique de mĂȘme que des essais de croisement et l'amplification au hasard de l'ADN polymorphique (RAPD) ont Ă©tĂ© utilisĂ©s pour dĂ©tecter les diffĂ©rences morphologiques et gĂ©nĂ©tiques entre populations d'#Heterorhabditis Pointar, 1975 provenant de Californie. Une nouvelle espĂšce, #Heterorhabditis hepialius sp. n., prĂ©sente dans des chenilles d'#Hepialis californicus provenant de la baie de Bodega (Californie, Etats-Unis d'AmĂ©rique) est dĂ©crite et illustrĂ©e. ReprĂ©sentant la huitiĂšme espĂšce du genre, #H. hepialius sp. n. est caractĂ©risĂ© par la morphologie des spicules, du gubernaculum, et de la queue de la femelle ainsi que les rapports E et F chez les juvĂ©niles infestants. Des donnĂ©es sur sa biologie sont Ă©galement fournies. (RĂ©sumĂ© d'auteur
PROMPT RADIATION EFFECTS ON CABLES AND LINEAR POWER INSTRUMENTATION CHANNELS
Tests were conducted to determine the amount of error introduced in reactor power data by radiation-induced voltages in cables and electrometer preamplifier chassis. The results, obtained near the central exposure facility of the KEWB (Reacter Safety Experiments), showed no observable radiation effects under the conditions of present use. Cable insulation resistance was measured during the radiation bursts. (C.J.G.
On the local systems Hamiltonian in the weakly nonlocal Poisson brackets
We study in this work the important class of nonlocal Poisson Brackets (PB)
which we call weakly nonlocal. They appeared recently in some investigations in
the Soliton Theory. However there was no theory of such brackets except very
special first order case. Even in this case the theory was not developed
enough. In particular, we introduce the Physical forms and find Casimirs,
Momentum and Canonical forms for the most important Hydrodynamic type PB of
that kind and their dependence on the boundary conditions.Comment: 45 pages, late
Bimodal Expansion of the Lymphatic Vessels Is Regulated by the Sequential Expression of IL-7 and Lymphotoxin α1ÎČ2 in Newly Formed Tertiary Lymphoid Structures.
Lymphangiogenesis associated with tertiary lymphoid structure (TLS) has been reported in numerous studies. However, the kinetics and dynamic changes occurring to the lymphatic vascular network during TLS development have not been studied. Using a viral-induced, resolving model of TLS formation in the salivary glands of adult mice we demonstrate that the expansion of the lymphatic vascular network is tightly regulated. Lymphatic vessel expansion occurs in two distinct phases. The first wave of expansion is dependent on IL-7. The second phase, responsible for leukocyte exit from the glands, is regulated by lymphotoxin (LT)ÎČR signaling. These findings, while highlighting the tight regulation of the lymphatic response to inflammation, suggest that targeting the LTα1ÎČ2/LTÎČR pathway in TLS-associated pathologies might impair a natural proresolving mechanism for lymphocyte exit from the tissues and account for the failure of therapeutic strategies that target these molecules in diseases such as rheumatoid arthritis
Evolution of a Holocene delta driven by episodic sediment delivery and coseismic deformation, Puget Sound, Washington, USA
This paper is not subject to U.S. copyright.
The definitive version was published in Sedimentology 53 (2006): 1211-1228, doi:10.1111/j.1365-3091.2006.00809.x.Episodic, large-volume pulses of volcaniclastic sediment and coseismic subsidence of the coast have influenced the development of a late Holocene delta at southern Puget Sound. Multibeam bathymetry, ground-penetrating radar (GPR) and vibracores were used to investigate the morphologic and stratigraphic evolution of the Nisqually River delta. Two fluvialâdeltaic facies are recognized on the basis of GPR data and sedimentary characteristics in cores, which suggest partial emplacement from sediment-rich floods that originated on Mount Rainier. Facies S consists of stacked, sheet-like deposits of andesitic sand up to 4 m thick that are continuous across the entire width of the delta. Flat-lying, highly reflective surfaces separate the sand sheets and comprise important facies boundaries. Beds of massive, pumice- and charcoal-rich sand overlie one of the buried surfaces. Organic-rich material from that surface, beneath the massive sand, yielded a radiocarbon age that is time-correlative with a series of known eruptive events that generated lahars in the upper Nisqually River valley. Facies CF consists of linear sandbodies or palaeochannels incised into facies S on the lower delta plain. Radiocarbon ages of wood fragments in the sandy channel-fill deposits also correlate in time to lahar deposits in upstream areas. Intrusive, sand-filled dikes and sills indicate liquefaction caused by post-depositional ground shaking related to earthquakes. Continued progradation of the delta into Puget Sound is currently balanced by tidal-current reworking, which redistributes sediment into large fields of ebb- and flood-oriented bedforms.This study was supported by the Coastal and
Marine Geology Program, and the Earthquake
Hazards Program of the U.S. Geological Survey
Rotational spectroscopy of isotopic vinyl cyanide, HC=CHCN, in the laboratory and in space
The rotational spectra of singly substituted C and N isotopic
species of vinyl cyanide have been studied in natural abundances between 64 and
351 GHz. In combination with previous results, greatly improved spectroscopic
parameters have been obtained which in turn helped to identify transitions of
the C species for the first time in space through a molecular line
survey of the extremely line-rich interstellar source Sagittarius B2(N) in the
3 mm region with some additional observations at 2 mm. The C species are
detected in two compact (), hot (170 K) cores with a column density
of and cm, respectively.
In the main source, the so-called ``Large Molecule Heimat'', we derive an
abundance of for each C species relative to H.
An isotopic ratio C/C of 21 has been measured. Based on a
comparison to the column densities measured for the C species of ethyl
cyanide also detected in this survey, it is suggested that the two hot cores of
Sgr B2(N) are in different evolutionary stages. Supplementary laboratory data
for the main isotopic species recorded between 92 and 342 GHz permitted an
improvement of its spectroscopic parameters as well.Comment: 18 pages, including 2 tables, 3 figures; plus one supplementary text
file plus one supplementary pdf file; J. Mol. Spectrosc., in press (to appear
in the July or August issue of 2008
Dynamical stability of infinite homogeneous self-gravitating systems: application of the Nyquist method
We complete classical investigations concerning the dynamical stability of an
infinite homogeneous gaseous medium described by the Euler-Poisson system or an
infinite homogeneous stellar system described by the Vlasov-Poisson system
(Jeans problem). To determine the stability of an infinite homogeneous stellar
system with respect to a perturbation of wavenumber k, we apply the Nyquist
method. We first consider the case of single-humped distributions and show
that, for infinite homogeneous systems, the onset of instability is the same in
a stellar system and in the corresponding barotropic gas, contrary to the case
of inhomogeneous systems. We show that this result is true for any symmetric
single-humped velocity distribution, not only for the Maxwellian. If we
specialize on isothermal and polytropic distributions, analytical expressions
for the growth rate, damping rate and pulsation period of the perturbation can
be given. Then, we consider the Vlasov stability of symmetric and asymmetric
double-humped distributions (two-stream stellar systems) and determine the
stability diagrams depending on the degree of asymmetry. We compare these
results with the Euler stability of two self-gravitating gaseous streams.
Finally, we determine the corresponding stability diagrams in the case of
plasmas and compare the results with self-gravitating systems
Search for and Using Genetic Programming Event Selection
We apply a genetic programming technique to search for the double Cabibbo
suppressed decays and .
We normalize these decays to their Cabibbo favored partners and find
\Lambda_c^+ \to p K^+ \pi^-\Lambda_c^+ \to p K^-
\pi^+ and D_s^+ \to K^+ K^+
\pi^-D_s^+ \to K^+ K^- \pi^+ where
the first errors are statistical and the second are systematic. Expressed as
90% confidence levels (CL), we find and respectively.
This is the first successful use of genetic programming in a high energy
physics data analysis.Comment: 10 page
Measurement of the D+ and Ds+ decays into K+K-K+
We present the first clear observation of the doubly Cabibbo suppressed decay
D+ --> K-K+K+ and the first observation of the singly Cabibbo suppressed decay
Ds+ --> K-K+K+. These signals have been obtained by analyzing the high
statistics sample of photoproduced charm particles of the FOCUS(E831)
experiment at Fermilab. We measure the following relative branching ratios:
Gamma(D+ --> K-K+K+)/Gamma(D+ --> K-pi+pi+) = (9.49 +/- 2.17(statistical) +/-
0.22(systematic))x10^-4 and Gamma(Ds+ --> K-K+K+)/Gamma(Ds+ --> K-K+pi+) =
(8.95 +/- 2.12(statistical) +2.24(syst.) -2.31(syst.))x10^-3.Comment: 10 pages, 8 figure
A Non-parametric Approach to the D+ to K*0bar mu+ nu Form Factors
Using a large sample of D+ -> K- pi+ mu+ nu decays collected by the FOCUS
photoproduction experiment at Fermilab, we present the first measurements of
the helicity basis form factors free from the assumption of spectroscopic pole
dominance. We also present the first information on the form factor that
controls the s-wave interference discussed in a previous paper by the FOCUS
collaboration. We find reasonable agreement with the usual assumption of
spectroscopic pole dominance and measured form factor ratios.Comment: 14 pages, 5 figures, and 2 tables. We updated the previous version by
changing some words, removing one plot, and adding two tables. These changes
are mostly stylisti
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