Direct Assessment of Juvenile Atlantic Bluefin Tuna: Integrating Sonar and Aerial Results in Support of Fishery-Incident Surveys

There is a clear need for direct assessment approaches for Atlantic bluefin tuna (Thunnus thynnus, ABFT), including formulation of experimental designs and pilot surveys for abundance estimation. In the western Atlantic, aerial surveys are highly feasible for juvenile ABFT because of their surface availability in summer and autumn on the mid-Atlantic shelf. Our goals are to design, implement, and analyze a fisheries-independent survey of juvenile ABFT and to assess the feasibility of biomass estimation in the Gulf of Maine (USA). From initial field trials using sonar and aerial mapping we demonstrated feasibility of determining size, area, and total biomass of schools as well as sizes of individuals within schools. We used aerial imagery to determine the school’s surface shape and to enumerate bluefin tuna visible in the upper few meters of the water column. The sonar data provided information on school height and number of individuals not captured in aerial photographs. By integrating sonar and aerial data we can estimate school biomass, number and sizes of individuals in schools, and aggregation behavior. In 2015 we plan to use a marine hexacopter to obtain more highly resolved aerial images of schools, with improved geo-rectification required for automated target recognition and objective counts of individuals. Current bluefin surveys rely primarily on observer and spotter pilot estimates of school metrics. Although not without challenges, the analytical techniques we’re developing will provide more objective, multi-dimensional information on ABFT schools and less biased estimates of biomass. Direct assessment also offers a means of tracking shifts in coastal distribution of highly mobile ABFT, especially as traditional indices of abundance may no longer be appropriate

Structural basis for dual roles of Aar2p in U5 snRNP assembly

Yeast U5 small nuclear ribonucleoprotein particle (snRNP) is assembled via a cytoplasmic precursor that contains the U5-specific Prp8 protein but lacks the U5-specific Brr2 helicase. Instead, pre-U5 snRNP includes the Aar2 protein not found in mature U5 snRNP or spliceosomes. Aar2p and Brr2p bind competitively to a C-terminal region of Prp8p that comprises consecutive RNase H-like and Jab1/MPN-like domains. To elucidate the molecular basis for this competition, we determined the crystal structure of Aar2p in complex with the Prp8p RNase H and Jab1/MPN domains. Aar2p binds on one side of the RNase H domain and extends its C terminus to the other side, where the Jab1/MPN domain is docked onto a composite Aar2p–RNase H platform. Known Brr2p interaction sites of the Jab1/MPN domain remain available, suggesting that Aar2p-mediated compaction of the Prp8p domains sterically interferes with Brr2p binding. Moreover, Aar2p occupies known RNA-binding sites of the RNase H domain, and Aar2p interferes with binding of U4/U6 di-snRNA to the Prp8p C-terminal region. Structural and functional analyses of phospho-mimetic mutations reveal how phosphorylation reduces affinity of Aar2p for Prp8p and allows Brr2p and U4/U6 binding. Our results show how Aar2p regulates both protein and RNA binding to Prp8p during U5 snRNP assembly

Response to Deltoid Muscle Injection of Hepatitis B Vaccine After Failure to Respond to Gluteal Injections

To the Editor. In their article entitled "Prehospital Cardiopulmonary Resuscitation: Is It Effective?" Cummins and Eisenberg state: "Clinical evidence provides strong support for efforts to increase the percent of persons in cardiac arrests who receive early bystander CPR [cardiopulmonary resuscitation]. These efforts do no harm and clearly save lives." We wish to report a subgroup of patients in whom early bystander-initiated CPR may be dramatically successful

Casimir energy in multiply connected static hyperbolic Universes

We generalize a previously obtained result, for the case of a few other static hyperbolic universes with manifolds of nontrivial topology as spatial sections.Comment: accepted for publicatio

Spontaneous Magnetization and Electron Momentum Density in 3D Quantum Dots

We discuss an exactly solvable model Hamiltonian for describing the interacting electron gas in a quantum dot. Results for a spherical square well confining potential are presented. The ground state is found to exhibit striking oscillations in spin polarization with dot radius at a fixed electron density. These oscillations are shown to induce characteristic signatures in the momentum density of the electron gas, providing a novel route for direct experimental observation of the dot magnetization via spectroscopies sensitive to the electron momentum density.Comment: 5 pages (Revtex4), 4 (eps) figure

Phonons and specific heat of linear dense phases of atoms physisorbed in the grooves of carbon nanotube bundles

The vibrational properties (phonons) of a one-dimensional periodic phase of atoms physisorbed in the external groove of the carbon nanotube bundle are studied. Analytical expressions for the phonon dispersion relations are derived. The derived expressions are applied to Xe, Kr and Ar adsorbates. The specific heat pertaining to dense phases of these adsorbates is calculated.Comment: 4 PS figure