Testing of Great Bay Oysters for Two Protozoan Pathogens

Two protozoan pathogens, Haplosporidium nelsoni (MSX) and Perkinsus marinus (Dermo) are known to be present in Great Bay oysters. With funds provided by the New Hampshire Estuaries Project (NHEP), the Marine Fisheries Division of New Hampshire Fish and Game Department, (NHF&G) continues to assess the presence and intensity of both disease conditions in oysters from the major beds, some open for harvest, within the Great Bay estuarine system. Histological examination of Great Bay oysters has also revealed other endoparasites

Testing of Great Bay Oysters for Two Protozoan Pathogens

Two protozoan pathogens, Haplosporidium nelsoni (MSX) and Perkinsus marinus(Dermo) are known to be present in Great Bay oysters. With funds provided by the New Hampshire Estuaries Project (NHEP), the Marine Fisheries Division of New Hampshire Fish and Game Department, (NHF&G) continues to assess the presence and intensity of both disease conditions in oysters from the major beds, some open for harvest, within the Great Bay estuarine system. Histological examination of Great Bay oysters has also revealed other endoparasites

Testing of Great Bay Oysters for Two Protazoan Pathogens

Two protozoan pathogens, Haplosporidium nelsoni (MSX) and Perkinsus marinus (Dermo) are known to be present in Great Bay oysters. With funds provided by the New Hampshire Estuaries Project (NHEP), the Marine Fisheries Division of New Hampshire Fish and Game Department, (NHF&G) continues to assess the presence and intensity of both disease conditions in oysters from the major beds, some open for harvest, within the Great Bay estuarine system. Histological examination of Great Bay oysters has also revealed other endoparasites

Centrality dependence of hyperon global polarization in Au+Au collisions at RHIC

We present the centrality dependence of Lambda and Anti-Lambda hyperon global polarization in Au+Au collisions at sqrt{s_NN}=62 GeV and 200 GeV measured with the STAR detector at RHIC. Within the precision of the measurement, we observe no centrality dependence of Lambda and Anti-Lambda hyperon global polarization and within our acceptance it is consistent with zero. Different sources of systematic uncertainties (feed down effects, spin precession) are discussed and estimated. The obtained upper limit, |P_{Lambda,Anti-Lambda}| < 0.02, is compared to theoretical predictions discussed recently in literatures.Comment: Talk given at QM 2006, The 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, November 14-20, 2006, Shanghai, China; 4 pages, 2 figure

Measurements of Transverse Spin Effects with the Forward Pion Detector of STAR

Measurements by the STAR collaboration of neutral pion production at large Feynman x (x_F) in the first polarized proton collisions at $\sqrt{s}=200$ GeV were reported previously. Cross sections measured at $\eta=3.3$, 3.8 and 4.0 are found to be consistent with next-to-leading order perturbative QCD calculations. The analyzing power is consistent with zero at negative x_F and at positive x_F up to ~0.3, then grows more positive with increasing x_F. This behavior can be described by phenomenological models including the Sivers effect, the Collins effect or higher twist contributions in the initial and final states. Forward calorimetry at STAR has been extended, and there are plans for further expansion. An integrated luminosity of 6.8 pb^${-1}$ with average beam polarization of 60% from online polarimetry measurements was sampled with the upgraded FPD in the 2006 RHIC run. This data sample will allow for a detailed map of the \pi^0 analyzing power over kinematic variables bounded by 0.3 < x_F < 0.6 and 1.2 < p_T < 5.0 GeV/c at $\sqrt{s}=200$ GeV. The expanded FPD has observed multi-photon final states expected to have "jet-like" characteristics. The transverse spin dependence of jet-like events can discriminate between the Collins and Sivers effects and lead to further progress in understanding the origin of single spin asymmetries in forward particle production. Data were also obtained at $\sqrt{s}=62.4$ GeV for x_F -> 1 to test predictions based on phenomenological fits to earlier STAR results. Recent results, the status of the analysis of 2006 run data and near-term plans will be discussed.Comment: 4 pages, 3 figures, to be published in the proceedings of the 17th International Spin Physics Symposium (SPIN2006), October 2-7, 2006, Kyoto, Japa

A Chemical Composition Survey of the Iron-Complex Globular Cluster NGC 6273 (M 19)

Recent observations have shown that a growing number of the most massive Galactic globular clusters contain multiple populations of stars with different [Fe/H] and neutron-capture element abundances. NGC 6273 has only recently been recognized as a member of this "iron-complex" cluster class, and we provide here a chemical and kinematic analysis of > 300 red giant branch (RGB) and asymptotic giant branch (AGB) member stars using high resolution spectra obtained with the Magellan-M2FS and VLT-FLAMES instruments. Multiple lines of evidence indicate that NGC 6273 possesses an intrinsic metallicity spread that ranges from about [Fe/H] = -2 to -1 dex, and may include at least three populations with different [Fe/H] values. The three populations identified here contain separate first (Na/Al-poor) and second (Na/Al-rich) generation stars, but a Mg-Al anti-correlation may only be present in stars with [Fe/H] > -1.65. The strong correlation between [La/Eu] and [Fe/H] suggests that the s-process must have dominated the heavy element enrichment at higher metallicities. A small group of stars with low [alpha/Fe] is identified and may have been accreted from a former surrounding field star population. The cluster's large abundance variations are coupled with a complex, extended, and multimodal blue horizontal branch (HB). The HB morphology and chemical abundances suggest that NGC 6273 may have an origin that is similar to omega Cen and M 54.Comment: Accepted for Publication in The Astrophysical Journal; 50 pages; 18 figures; 8 tables; higher resolution figures are available upon request or in the published journal articl

Exploring the Chemical Composition and Double Horizontal Branch of the Bulge Globular Cluster NGC 6569

Photometric and spectroscopic analyses have shown that the Galactic bulge cluster Terzan 5 hosts several populations with different metallicities and ages that manifest as a double red horizontal branch (HB). A recent investigation of the massive bulge cluster NGC 6569 revealed a similar, though less extended, HB luminosity split, but little is known about the cluster's detailed chemical composition. Therefore, we have used high-resolution spectra from the Magellan-M2FS and VLT-FLAMES spectrographs to investigate the chemical compositions and radial velocity distributions of red giant branch and HB stars in NGC 6569. We found the cluster to have a mean heliocentric radial velocity of -48.8 km/s (sigma = 5.3 km/s; 148 stars) and a mean [Fe/H] =-0.87 dex (19 stars), but the cluster's 0.05 dex [Fe/H] dispersion precludes a significant metallicity spread. NGC 6569 exhibits light- and heavy-element distributions that are common among old bulge/inner Galaxy globular clusters, including clear (anti)correlations between [O/Fe], [Na/Fe], and [Al/Fe]. The light-element data suggest that NGC 6569 may be composed of at least two distinct populations, and the cluster's low mean [La/Eu] = -0.11 dex indicates significant pollution with r-process material. We confirm that both HBs contain cluster members, but metallicity and light-element variations are largely ruled out as sources for the luminosity difference. However, He mass fraction differences as small as delta Y ~ 0.02 cannot be ruled out and may be sufficient to reproduce the double HB.Comment: 72 pages, 14 figures, 8 tables; published in The Astronomical Journal; electronic versions of all tables are available in the published versio

The visual binary AG Tri in β\beta Pictoris Association: can a debris disc cause very different rotation periods of its components?

We measure the photometric rotation periods of the components of multiple systems in young stellar associations to investigate the causes of the observed rotation period dispersion. We present the case of the wide binary AG Tri in the 23-Myr young beta Pictoris Association consisting of K4 + M1 dwarfs. Our multi-band, multi-season photometric monitoring allowed us to measure the rotation periods of both components P_A = 12.4d and P_B = 4.66d, to detect a prominent magnetic activity in the photosphere, likely responsible for the measured radial velocity variations, and for the first time, a flare event on the M1 component AG Tri B. We investigate either the possibility that the faster rotating component may have suffered an enhanced primordial disc dispersal, starting its PMS spin-up earlier than the slower rotating component, or the possibility that the formation of a debris disc may have prevented AG Tri A from gaining part of the angular momentum from the accreting disc.Comment: 28 pages, 7 figures, accepted for publication in Astrophysics and Space Science 2015, (ASTR-D-15-00445R2

Tree growth and management in Ugandan agroforestry systems: effects of root pruning on tree growth and crop yield

Tree root pruning is a potential tool for managing below-ground competition when trees and crops are grown together in agroforestry systems. This study investigates its effects on growth and root distribution of Alnus acuminata (HB & K), Casuarina equisetifolia (L), Grevillea robusta (A. Cunn. ex R. Br), Maesopsis eminii (Engl.), and Markhamia lutea (Benth.) K. Schum. and on yield of adjacent crops in sub-humid Uganda. The trees were 3 years old at the commencement of the study, and most species were competing strongly with crops. Tree roots were pruned 41 months after planting by cutting and back-filling a trench to a depth of 0.3 m, at a distance of 0.3 m from the trees, on one side of the tree row. The trench was re-opened and roots re-cut at 50 and 62 months after planting. Effects on tree growth and root distribution were assessed over a 3 year period, and crop yield after the third root pruning at 62 months is reported here. Overall, root pruning had only a slight effect on tree growth: height growth was unaffected and diameter growth was reduced by only 4 %. A substantial amount of root re-growth was observed by 11 months after pruning. Tree species varied in the number and distribution of their roots, and Casuarina and Markhamia had considerably more roots per unit of trunk volume than the other tree species, especially in the surface soil layers. Casuarina and Maesopsis were the most competitive tree species with crops and Grevillea and Markhamia the least. Crop yield data provides strong evidence of the redistribution of root activity following root pruning, so that competition increased on the unpruned side of tree rows. Thus, one-sided root pruning will only be of use to farmers in a few circumstances. Key words: Alnus acuminata, Casuarina equisetifolia, Grevillea robusta, Maesopsis eminii, Markhamia lutea, root distribution, root functio