Microsatellite and mitochondrial DNA analysis of Dungeness crab (Cancer magister) from California to northern British Columbia

Genetic variation was assessed using mitochondrial DNA and microsatellite markers from Dungeness crab between Iceberg Bay, British Columbia and San Luis Obispo, California. We found little pattern in overall genetic variation between sites in both marker types, and no significant Isolation by Distance model was fit. Site-specific variation in mitochondrial DNA haplotype frequencies suggested the existence of three subpopulations associated with the Alaska Current, the Puget Sound, and the California Current, but microsatellite DNA evidence did not support it. The ratio between sampling size for microsatellite markers and fragment size polymorphisms was low, limiting the resolving power of microsatellite DNA for neutral variation. Average pairwise Fst values for Iceberg Bay, British Columbia against all other populations was 0.156, as compared to the average pairwise Fst of 0.028 across all populations. In the southern region of the Puget Sound, Nisqually, Washington had a lower pairwise Fst of 0.044 but contained a large number of site-specific, unique mtDNA haplotypes. Additionally, we found 41 mtDNA haplotypes in 445 samples taken, with 23 of those haplotypes as singletons, suggesting that Dungeness crab went through a recent, post-bottleneck population expansion, likely associated with the most recent glacial relaxation

Autonomous rendezvous and capture development infrastructure

In the development of the technology for autonomous rendezvous and docking, key infrastructure capabilities must be used for effective and economical development. This need involves facility capabilities, both equipment and personnel, to devise, develop, qualify, and integrate ARD elements and subsystems into flight programs. One effective way of reducing technical risks in developing ARD technology is the use of the Low Earth Orbit test facility. Using a reusable free-flying testbed carried in the Shuttle, as a technology demonstration test flight, can be structured to include a variety of sensors, control schemes, and operational approaches. This testbed and flight demonstration concept will be used to illustrate how technologies and facilities at MSFC can be used to develop and prove an ARD system

Tackling the Global NCD Crisis: Innovations in Law and Governance

35 million people die annually of non-communicable diseases (NCDs), 80% of them in low- and middle-income countries—representing a marked epidemiological transition from infectious to chronic diseases and from richer to poorer countries. The total number of NCDs is projected to rise by 17% over the coming decade, absent significant interventions. The NCD epidemic poses unique governance challenges: the causes are multifactorial, the affected populations diffuse, and effective responses require sustained multi-sectorial cooperation. The authors propose a range of regulatory options available at the domestic level, including stricter food labeling laws, regulation of food advertisements, tax incentives for healthy lifestyle choices, changes to the built environment, and direct regulation of food and drink producers. Given the realities of globalization, such interventions require global cooperation. In 2011, the UN General Assembly held a High-level meeting on NCDs, setting a global target of a 25% reduction in premature mortality from NCDs by 2025. Yet concrete plans and resource commitments for reaching this goal are not yet in the offing, and the window is rapidly closing for achieving these targets through prevention--as opposed to treatment, which is more costly. Innovative global governance for health is urgently needed to engage private industry and civil society in the global response to the NCD crisis

Flexible Electrostatic Technologies for Capture and Handling, Phase 1

Fundamental to many of NASA's in-space transportation missions is the capture and handling of various objects and vehicles in various orbits for servicing, debris disposal, sample retrieval, and assembly without the benefit of sufficient grapple fixtures and docking ports. To perform similar material handling tasks on Earth, pincher grippers, suction grippers, or magnetic chucks are used, but are unable to reliably grip aluminum and composite spacecraft, insulation, radiators, solar arrays, or extra-terrestrial objects in the vacuum of outer space without dedicated handles in the right places. The electronic Flexible Electrostatic Technologies for space Capture and Handling (FETCH) will enable reliable and compliant gripping (soft dock) of practically any object in various orbits or surfaces without dedicated mechanical features, very low impact capture, and built-in proximity sensing without any conventional actuators. Originally developed to handle semiconductor and glass wafers during vacuum chamber processing without contamination, the normal rigid wafer handling chucks are replaced with thin metal foil segments laminated in flexible insulation driven by commercial off-the-shelf solid state, high-voltage power supplies. Preliminary testing in NASA Marshall Space Flight Center's (MSFC's) Flat Floor Robotics Lab demonstrated compliant alignment and gripping with a full-sized, 150-lb microsat mockup and translation before a clean release with a flip of a switch. The flexible electrostatic gripper pads can be adapted to various space applications with different sizes, shapes, and foil electrode layouts even with openings through the gripper pads for addition of guidance sensors or injection of permanent adhesives. With gripping forces estimated between 0.5 and 2.5 lb/in2 or 70-300 lb/ft2 of surface contact, the FETCH can turn on and off rapidly and repeatedly to enable sample handling, soft docking, in-space assembly, precision relocation, and surface translation for accurate anchoring

Production Regimes for Self-Interacting Dark Matter

In the context of Self-Interacting Dark Matter as a solution for the small-scale structure problems, we consider the possibility that Dark Matter could have been produced without being in thermal equilibrium with the Standard Model bath. We discuss one by one the following various dark matter production regimes of this kind: freeze-in, reannihilation and dark freeze-out. We exemplify how these mechanisms work in the context of the particularly simple Hidden Vector Dark Matter model. In contrast to scenarios where there is thermal equilibrium with the Standard Model bath, we find two regimes which can easily satisfy all the laboratory and cosmological constraints. These are dark freeze-out with 3-to-2 annihilations and freeze-in via a light mediator. In the first regime, different temperatures in the visible and the Dark Matter sectors allow us to avoid the constraints coming from cosmic structure formation as well as the use of non-perturbative couplings to reproduce the observed relic density. For the second regime, different couplings are responsible for Dark Matter relic density and self-interactions, permitting to surpass BBN, X-ray, CMB and direct detection constraints.Comment: 40 pages, 14 figures. Accepted for publication in JCA

Synthesis and Application of Oil-Soluble Polymer Brush-Grafted Silica Nanoparticles as Lubricant Additives for Friction and Wear Reduction

Although inorganic and metallic nanoparticles are potentially effective oil lubricant additives for friction and wear reduction, their high tendency to undergo aggregation and precipitation in base oils has been an obstacle for real-world applications. This dissertation research aims to develop oil-soluble, polymer brush-grafted nanoparticles (hairy NPs) for use as additives for base oils such as polyalphaolefin (PAO). Well-defined hairy NPs were synthesized by surface-initiated reversible addition-fragmentation chain transfer polymerization from chain transfer agent-functionalized, 23 nm silica NPs, and their lubrication properties were investigated in PAO by high-contact-stress ball-on-flat reciprocating sliding tribological tests.The effects of alkyl pendant groups of poly(alkyl methacrylate) brushes on oil dispersibility, stability, and tribological properties of hairy NPs were studied. It was found that hairy NPs with sufficiently long alkyl pendants ( \u3e 8 carbon atoms, such as 12, 13, and 16) were readily dispersed in PAO and formed homogeneous, clear dispersions with long-term stability over a wide temperature range. Significant friction and wear reductions were achieved by using 1 wt% homogenous dispersions of hairy NPs in PAO. In an effort to increase the function of polymer brushes through the introduction of triboactive phosphorus into the grafted polymers, three phosphonate-containing monomers were synthesized and copolymerized with a long alkyl methacrylate. A significant amount of phosphonate can be incorporated into the brushes without comprising the dispersibility of hairy NPs in PAO. A synergistic effect of combining hairy NPs with a phosphonium-phosphate ionic liquid as PAO additives was discovered. The lubricating performance was improved significantly when the two additives were mixed at certain ratios. Analysis showed that both silica NPs and the ionic liquid participated in the tribo-chemical reaction. These research efforts have shown that hairy NPs have promise for use as lubricant additives. Lastly, as a side project, a series of isotactic and atactic polyethers with monosulfone-containing pendants were synthesized by the reaction of corresponding poly(epichlorohydrin) with various n-alkanethiols and subsequent oxidation of thioether groups with a goal of seeking ferroelectric liquid crystalline polymers for use in solid state cooling. The isotactic poly((R)-epichlorohydrin) was synthesized by ring-opening polymerization of (R)-(-)-epichlorohydrin using a commercial methylaluminoxane as the catalyst

Universal Two-Electron Correlation Operator on Excited States

Excited states of chemical systems are extremely important in understanding spectra, chemical phenomena, as well as how a particular compound behaves in reactions. Computationally, excited states are normally very expensive to calculate. The difficulty in calculating these states with wavefunction based methods can be mainly attributed to the calculation of large multi-determinant wavefunctions. One reason to use a complicated multi-determinant wavefunction is to include some of the effects of correlation energy. The quantity of correlation energy can most simply be defined as the reduction in energy caused by any two or more electrons trying to avoid each other. The most common way of avoiding these computational costs is through the use of time-dependent density functional theory (TD-DFT). TD-DFT has an exceptional ratio of accuracy to computational cost because it reduces the many-electron wavefunction to a single-electron density. A single-electron quantity, however, is an improper way to descibe an innately two-electron property like correlation energy. Within this research we seek to alleviate the large computational costs required to calculate excited states with a wavefunction-based method and reduce the costs to near Hartree-Fock theory levels. We do this by using two different inexpensive excited wavefunction methods. First we reduce our multi-determinant wavefunction to a single-determinant wavefunction. The single-determinant wavefunction used in this research comes from delta self-consistent field method that essentially creates excited Hartree-Fock states. Secondly we construct the simplest multi-configurational wavefunction using a linear combination of all singly excited states with the method known as configuration interaction singles (CIS). The reduction in wavefunction size, however, reduces nearly all correlation energy recovered by both methods. This is remedied by modeling correlation energy in a computationally inexpensive manner. A potentially accurate way to model electron correlation within the single determinant wavefunction formalism is through the expectation value of a linear two-electron operator over the Kohn-Sham single-determinant wavefunction. For practical reasons, it is desirable for such an operator to be universal, i.e. independent of the positions and types of nuclei in a molecule. We choose an operator expanded in a small number of Gaussians as a model for electron correlation. The accuracy of this method is tested by computing atomic and molecular adiabatic excited states in comparison with popular TD-DFT functionals. The correlation operator combined with SCF is found to be comparable in accuracy to TD-DFT methods for both atomic and molecular excited states. SCF is limited in its applications, however, due to its inability to guarantee orthogonal excited states which leads to unwanted spin contamination. The correlation operator combined with CIS is found to be comparable in accuracy to TD-DFT methods for atomic states but has a significant loss in accuracy for excited molecular states. This drop in accuracy is theorized to be the poor description Hartree Fock theory gives of some ground and excited state wavefunctions.. We offer some possible solutions to these problems in the form of orthogonality constraints and a potential hybrid method of SCF and CIS