skip to main content

Search for: All records

Creators/Authors contains: "Dodd, L."

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Abstract

    Ocean acidification is predicted to impair marine calcifiers' abilities to produce shells and skeletons. We conducted laboratory experiments investigating the impacts of CO2‐induced ocean acidification (pCO2 = 478–519, 734–835, 8,980–9,567; Ωcalcite = 7.3–5.7, 5.6–4.3, 0.6–0.7) on calcification rates of two estuarine calcifiers involved in a classic predator‐prey model system: adultPanopeus herbstii(Atlantic mud crab) and juvenileCrassostrea virginica(eastern oyster). Both oyster and crab calcification rates significantly decreased at the highestpCO2level. Notably, however, oysters maintained positive net calcification rates in the highest pCO2treatment that was undersaturated with respect to calcite, while mud crabs exhibited net dissolution (i.e., net loss of shell mass) in calcite‐undersaturated conditions. Secondary electron imaging of oyster shells revealed minor microstructural alterations in the moderate‐pCO2treatment, and major microstructural and macrostructural changes (including shell dissolution, delamination of periostracum) in the high‐pCO2treatment. These results underscore the threat that ocean acidification poses for marine organisms that produce calcium carbonate shells, illustrate the strong biological control that some marine calcifiers exert over their shell‐building process, and shows that ocean acidification differentially impacts the crab and oyster species involved in this classical predator‐prey model system.

    more » « less
  2. null (Ed.)
    A bstract Jet production in lead-lead (PbPb) and proton-proton (pp) collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV is studied with the CMS detector at the LHC, using PbPb and pp data samples corresponding to integrated luminosities of 404 μ b − 1 and 27.4 pb − 1 , respectively. Jets with different areas are reconstructed using the anti- k T algorithm by varying the distance parameter R . The measurements are performed using jets with transverse momenta ( p T ) greater than 200 GeV and in a pseudorapidity range of |η| < 2. To reveal the medium modification of the jet spectra in PbPb collisions, the properly normalized ratio of spectra from PbPb and pp data is used to extract jet nuclear modification factors as functions of the PbPb collision centrality, p T and, for the first time, as a function of R up to 1.0. For the most central collisions, a strong suppression is observed for high- p T jets reconstructed with all distance parameters, implying that a significant amount of jet energy is scattered to large angles. The dependence of jet suppression on R is expected to be sensitive to both the jet energy loss mechanism and the medium response, and so the data are compared to several modern event generators and analytic calculations. The models considered do not fully reproduce the data. 
    more » « less
  3. null (Ed.)
  4. null (Ed.)
    A bstract We present the first study of charged-hadron production associated with jets originating from b quarks in proton-proton collisions at a center-of-mass energy of 5.02 TeV. The data sample used in this study was collected with the CMS detector at the CERN LHC and corresponds to an integrated luminosity of 27.4 pb − 1 . To characterize the jet substructure, the differential jet shapes, defined as the normalized transverse momentum distribution of charged hadrons as a function of angular distance from the jet axis, are measured for b jets. In addition to the jet shapes, the per-jet yields of charged particles associated with b jets are also quantified, again as a function of the angular distance with respect to the jet axis. Extracted jet shape and particle yield distributions for b jets are compared with results for inclusive jets, as well as with the predictions from the pythia and herwig++ event generators. 
    more » « less
  5. null (Ed.)
  6. null (Ed.)
  7. null (Ed.)