A comparison of vegetation suppression and sod-seeding methods using perennial ryegrass in renovation of non-irrigated permament pastures in western Oregon

Sod-seeding techniques offer graziers a convenient way to introduce superior grass cultivars into underproductive permanent pastures. Production loss and erosion are minimized. In conjunction with improved grazing management and fertilization, renovation can significantly improve yield and quality of pastures. Existent vegetation must be suppressed prior to introducing new cultivars. This study was conducted on two non-irrigated pastures near Corvallis, Oregon, one dominated by annual grass species and the other by perennial grasses and clover. A split-plot design with four replications on each site was used to compare three seeding methods and either (a) two herbicides following close mowing or (b) close mowing alone. The seeding methods were drilling with an Aerway Seedmatic chisel-type drill, drilling with a Tye double disc drill, or broadcasting seed followed by harrowing. Glyphosate and paraquat were the herbicides used for vegetation suppression. Effect of fertilization was compared to no fertilization. Sod-seeded perennial ryegrass had minimal establishment at the site dominated by annual grass species. An inadequate amount of time was allowed for germination of annual grass seeds before herbicides were applied. Annual grass seedlings suppressed the newly sod-seeded perennial ryegrass. Sod-seeded perennial ryegrass was successfully established at the site dominated by perennial species within one year after planting. Broadcasting followed by harrowing of seed resulted in a higher percentage of perennial ryegrass than either the Seedmatic chisel drill or Tye double disc drill. Sod-seeded perennial ryegrass did not contribute significantly to yield until one year after planting. Glyphosate gave better control of the species present before planting leading to a higher percentage of perennial ryegrass and improved yield compared to paraquat or close mowing alone when seed was broadcast and harrowed. Fertilization of unseeded plots increased yield but was not cost-effective

WHITE‐CROWNED MANAKIN (DIXIPHIA PIPRA) USE OF SPACE IN THE ECUADORIAN AMAZON

Abstract ∙ Animal patterns of space use have fundamental consequences for ecological processes such as animal‐ mediated seed dispersal. This study examines the use of space of an understory frugivore: the White‐crowned Manakin (Dixiphia pipra) during the non‐breeding season at Tiputini Biodiversity Station in Ecuador. We radio‐tracked seven individuals of different sexes and ages. We found that White‐crowned Manakins have relatively small home ranges varying from 1.19 to 5.73 ha. The home ranges of male juveniles (2.25 ± 0.62 SE) were larger than that of the adult males (1.20 ± 0.01 SE), but smaller than those of females (4.27 ± 0.77 SE). Females and second‐year males were found to perform more long distance flights outside their core home range than hatch‐year or adult males. These movement differences suggest that they disperse seeds longer distances and more evenly across their home range. Adult and hatch‐year males appear to perform more short distance seed dispersal events. We argue that these contributions are complementary, and that White‐crowned Manakins are key dispersal agents that have a significantly influence in the structure and composition of understory plant communities in the Amazon rainforest.Resumen ∙ Uso de espacio del Saltarín Coroniblanco (Dixiphia pipra) en la Amazonía Ecuatoriana Los patrones de uso espacial utilizados por animales tienen consecuencias fundamentales en procesos ecológicos, tales como la dispersión de semillas. Este estudio examina el uso espacial de una especie frugívora de sotobosque: el Saltarín Coroniblanco (Dixiphia pipra) durante el ciclo no‐reproductivo en la Estación de Biodiversidad de Tiputini en Ecuador. Seguimos por radio telemetría a siete individuos de diferentes sexos y edades. Encontramos que el Saltarín Coroniblanco tiene un rango de hogar relativamente pequeño, variando entre 1,19 a 5,73 ha. El rango de hogar de los machos juveniles (2,25 ± 0,62 EE) es más grande que el de los machos adultos (1,20 ± 0,01 EE), pero más pequeño que el de las hembras (4,27 ± 0,77 EE). El estudio encontró que las hembras y los machos de segundo año realizaron vuelos más largos fuera del núcleo de su rango de hogar, comparado con machos juveniles del año o machos adultos. Estas diferencias sugieren que podrían dispersar semillas a mayores distancias y de manera más homogénea a lo largo de su rango de hogar. Los machos adultos y los juveniles del año parecen llevar a cabo eventos de dispersión de semillas a distancias más cortas. Nosotros argumentamos que estas contribuciones son complementarias y que los Saltarines Coroniblancos son agentes de dispersión claves, influenciando considerablemente la estructura y la composición de las comunidades de plantas del sotobosque en el bosque tropical lluvioso de la Amazonía Ecuatoriana.

Multi-boson effects and the normalization of the two-pion correlation function

The two-pion correlation function can be defined as a ratio of either the measured momentum distributions or the normalized momentum space probabilities. We show that the first alternative avoids certain ambiguities since then the normalization of the two-pion correlator contains important information on the multiplicity distribution of the event ensemble which is lost in the second alternative. We illustrate this explicitly for specific classes of event ensembles.Comment: 6 pages, three figures,submit to PR

Association of the rs2242446 polymorphism in the norepinephrine transporter gene SLC6A2 and anxious arousal symptoms of posttraumatic stress disorder

To the Editor: Recently, we found that greater norepinephrine transporter (NET) availability in the locus ceruleus of trauma survivors with posttraumatic stress disorder (PTSD) was associated with increased severity of anxious arousal (ie, hypervigilance and exaggerated startle) symptoms, but not any of the other empirically derived symptom clusters that characterize this disorder.1 This finding suggests that greater NET availability in the locus ceruleus may serve a compensatory function of clearing elevated synaptic norepinephrine and maintaining anxious arousal symptoms in persons with PTSD

Association of the rs2242446 polymorphism in the norepinephrine transporter gene SLC6A2 and anxious arousal symptoms of posttraumatic stress disorder

To the Editor: Recently, we found that greater norepinephrine transporter (NET) availability in the locus ceruleus of trauma survivors with posttraumatic stress disorder (PTSD) was associated with increased severity of anxious arousal (ie, hypervigilance and exaggerated startle) symptoms, but not any of the other empirically derived symptom clusters that characterize this disorder.1 This finding suggests that greater NET availability in the locus ceruleus may serve a compensatory function of clearing elevated synaptic norepinephrine and maintaining anxious arousal symptoms in persons with PTSD

Bounds for Bose-Einstein Correlation Functions

Bounds for the correlation functions of identical bosons are discussed for the general case of a Gaussian density matrix. In particular, for a purely chaotic system the two-particle correlation function must always be greater than one. On the other hand, in the presence of a coherent component the correlation function may take values below unity. The experimental situation is briefly discussed.Comment: 7 pages, LaTeX, DMR-THEP-93-5/

Factorial Moments of Continuous Order

The normalized factorial moments $F_q$ are continued to noninteger values of the order $q$, satisfying the condition that the statistical fluctuations remain filtered out. That is, for Poisson distribution $F_q = 1$ for all $q$. The continuation procedure is designed with phenomenology and data analysis in mind. Examples are given to show how $F_q$ can be obtained for positive and negative values of $q$. With $q$ being continuous, multifractal analysis is made possible for multiplicity distributions that arise from self-similar dynamics. A step-by-step procedure of the method is summarized in the conclusion.Comment: 15 pages + 9 figures (figures available upon request), Late

One and two dimensional analysis of 3pi correlations measured in Pb+Pb interactions

3pi- correlations from Pb+Pb collisions at 158 GeV/c per nucleon are presented as measured by the focusing spectrometer of the NA44 experiment at CERN. The three-body effect is found to be stronger for PbPb than for SPb. The two-dimensional three-particle correlation function is also measured and the longitudinal extension of the source is larger than the transverse extension

A sensitive test for models of Bose-Einstein correlations

Accurate and sensitive measurements of higher order cumulants open up new approaches to pion interferometry. It is now possible to test whether a given theoretical prediction can consistently match cumulants of both second and third order. Our consistency test utilizes a new technique combining theoretically predicted functions with experimentally determined weights in a quasi-Monte Carlo approach. Testing a general quantum statistics-based framework of Bose-Einstein correlations with this technique, we find that predictions for third order cumulants differ significantly from UA1 data. This discrepancy may point the way to more detailed dynamical information.Comment: 5 pages, 2 figures, revte

Multi-pion correlations in high energy collisions

Any-order pion inclusive distribution for a chaotic source in high energy collisions are given which can be used in both theory and experiment to analyze any-order pion interferometry. Multi-pion correlations effects on two-pion and three-pion interferometry are discussed.Comment: Eq.(25) and Eq.(26) are correcte