Spatial dependences in the distant solar wind: Pioneers 10 and 11

Pioneer 10, 11 observations of the solar wind and magnetic field between 1 and 20 AU are reviewed. Spatial dependences, which are emphasized, must be inferred in the presence of large temporal variations including solar cycle effects. The separation of spatial and temporal dependences is achieved principally through the use of multipoint observations including baseline measurements at 1 AU. Measurements of the solar wind parameters (radial speed, flux, proton temperature) and of the magnetic field magnitude and components are compared with two theories, the Parker theory which assumes radial, azimuthally symmetric flow and the Goldstein-Jokipii theory which includes effects associated with stream-stream interactions. The observed radial gradients in the proton density and velocity and the magnetic field are consistent with the Parker model. A qualitative dependence of field magnitude on heliomagnetic latitude, i.e., referred to the observed location of the heliospheric current sheet, was derived. The field strength was found to decrease with distance from the current sheet

Brown bullhead catfish (ameiurus nebulosus) in Lake Taupo

Brown bullhead catfish (Ameiurus nebulosus) were first discovered in Lake Taupo during the early 1980s and are believed to have originated from an illegal liberation into the southern end of the lake. A native of the southern and eastern states of America, these catfish have been in New Zealand since 1878 and are now widespread throughout the Waikato region. In 1995 the population structure, abundance, age, growth rate and diet of catfish in the littoral zone (150 mm FL) and small fish. Low numbers of catfish across all size classes were caught from exposed sandy sites. The diet of catfish was size and habitat dependent. Small catfish (<150 mm FL) fed predominantly on chironomids, Cladocera, gastropods, caddisfly larvae, plant material and detritus. Larger catfish were found to prey to a greater extent on koura (Paranephrops planifrons), fish and terrestrial invertebrates

Predicting Alzheimer's risk: why and how?

Because the pathologic processes that underlie Alzheimer's disease (AD) appear to start 10 to 20 years before symptoms develop, there is currently intense interest in developing techniques to accurately predict which individuals are most likely to become symptomatic. Several AD risk prediction strategies - including identification of biomarkers and neuroimaging techniques and development of risk indices that combine traditional and non-traditional risk factors - are being explored. Most AD risk prediction strategies developed to date have had moderate prognostic accuracy but are limited by two key issues. First, they do not explicitly model mortality along with AD risk and, therefore, do not differentiate individuals who are likely to develop symptomatic AD prior to death from those who are likely to die of other causes. This is critically important so that any preventive treatments can be targeted to maximize the potential benefit and minimize the potential harm. Second, AD risk prediction strategies developed to date have not explored the full range of predictive variables (biomarkers, imaging, and traditional and non-traditional risk factors) over the full preclinical period (10 to 20 years). Sophisticated modeling techniques such as hidden Markov models may enable the development of a more comprehensive AD risk prediction algorithm by combining data from multiple cohorts. As the field moves forward, it will be critically important to develop techniques that simultaneously model the risk of mortality as well as the risk of AD over the full preclinical spectrum and to consider the potential harm as well as the benefit of identifying and treating high-risk older patients

Working with Nonassociative Geometry and Field Theory

We review aspects of our formalism for differential geometry on noncommutative and nonassociative spaces which arise from cochain twist deformation quantization of manifolds. We work in the simplest setting of trivial vector bundles and flush out the details of our approach providing explicit expressions for all bimodule operations, and for connections and curvature. As applications, we describe the constructions of physically viable action functionals for Yang-Mills theory and Einstein-Cartan gravity on noncommutative and nonassociative spaces, as first steps towards more elaborate models relevant to non-geometric flux deformations of geometry in closed string theory.Comment: 20 pages; v2: Reference added; Contribution to the proceedings of the Corfu Summer Institute on Elementary Particle Physics and Gravity, September 1-26, 2015, Corfu, Greece; Final version published in Proceedings of Scienc

Implications of a DK Molecule at 2.32 GeV

We discuss the implications of a possible quasinuclear DK bound state at 2.32 GeV. Evidence for such a state was recently reported in D_s^+pi^o by the BaBar Collaboration. We first note that a conventional quark model c-sbar assignment is implausible, and then consider other options involving multiquark systems. An I=0 c sbar n nbar baryonium assignment is one possibility. We instead favor a DK meson molecule assignment, which can account for the mass and quantum numbers of this state. The higher-mass scalar c-sbar state expected at 2.48 GeV is predicted to have a very large DK coupling, which would encourage formation of an I=0 DK molecule. Isospin mixing is expected in hadron molecules, and a dominantly I=0 DK state with some I=1 admixture could explain both the narrow total width of the 2.32 GeV state as well as the observed decay to D_s^+ pi^o. Additional measurements that can be used to test this and related scenarios are discussed.Comment: 6 pages, 1 figur

Options for the SELEX state D_{s\J}^+(2632)

We consider possible assignments for the D_{s\J}^+(2632), which was recently reported in D$_s^+\eta$ and D$^0$K$^+$ final states by the SELEX Collaboration at Fermilab. The most plausible quark model assignment for this state is the first radial excitation ($2^3\S_1$) of the $c\bar s$ D$_s^*(2112)$, although the predicted mass and strong decay branching fractions for this assignment are not in agreement with the SELEX data. The reported dominance of D$_s\eta$ over DK appears especially problematic. An intriguing similarity to the K$^*(1414)$ is noted. $2^3\S_1$--^3\D_1 configuration mixing is also considered, and we find that this effect is unlikely to resolve the branching fraction discrepancy. Other interpretations as a $c\bar s$-hybrid or a two-meson molecule are also considered, but appear unlikely. Thus, if this state is confirmed, it will require reconsideration of the systematics of charmed meson spectroscopy and strong decays.Comment: 6 revtex4 pages, 2 eps figure

Massive quark scattering at strong coupling from AdS/CFT

We extend the analysis of Alday and Maldacena for obtaining gluon scattering amplitudes at strong coupling to include external massive quark states. Our quarks are actually the N=2 hypermultiplets which arise when D7-brane probes are included in the AdS_5 x S^5 geometry. We work in the quenched approximation, treating the N=2 matter multiplets as external sources coupled to the N=4 SYM fields. We first derive appropriate massive-particle boundary conditions for the string scattering worldsheets. We then find an exact worldsheet which corresponds to the scattering of two massive quarks and two massless gluons and extract from this the associated scattering amplitude. We also find the worldsheet and amplitude for the scattering of four massive quarks. Our worldsheet solutions reduce to the four massless gluon solution of Alday and Maldacena in the limit of zero quark mass. The amplitudes we compute can also be interpreted in terms of 2-2 scattering involving gluons and massive W-bosons.Comment: 46 pages, 11 figures, v4: additional comments added to intr

Independent Orbiter Assessment (IOA): FMEA/CIL assessment

The McDonnell Douglas Astronautics Company (MDAC) was selected to perform an Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL). Direction was given by the Orbiter and GFE Projects Office to perform the hardware analysis and assessment using the instructions and ground rules defined in NSTS 22206. The IOA analysis featured a top-down approach to determine hardware failure modes, criticality, and potential critical items. To preserve independence, the analysis was accomplished without reliance upon the results contained within the NASA and Prime Contractor FMEA/CIL documentation. The assessment process compared the independently derived failure modes and criticality assignments to the proposed NASA post 51-L FMEA/CIL documentation. When possible, assessment issues were discussed and resolved with the NASA subsystem managers. Unresolved issues were elevated to the Orbiter and GFE Projects Office manager, Configuration Control Board (CCB), or Program Requirements Control Board (PRCB) for further resolution. The most important Orbiter assessment finding was the previously unknown stuck autopilot push-button criticality 1/1 failure mode. The worst case effect could cause loss of crew/vehicle when the microwave landing system is not active. It is concluded that NASA and Prime Contractor Post 51-L FMEA/CIL documentation assessed by IOA is believed to be technically accurate and complete. All CIL issues were resolved. No FMEA issues remain that have safety implications. Consideration should be given, however, to upgrading NSTS 22206 with definitive ground rules which more clearly spell out the limits of redundancy