Science is perception: what can our sense of smell tell us about ourselves and the world around us?

Human sensory processes are well understood: hearing, seeing, perhaps even tasting and touch—but we do not understand smell—the elusive sense. That is, for the others we know what stimuli causes what response, and why and how. These fundamental questions are not answered within the sphere of smell science; we do not know what it is about a molecule that … smells. I report, here, the status quo theories for olfaction, highlighting what we do not know, and explaining why dismissing the perception of the input as ‘too subjective’ acts as a roadblock not conducive to scientific inquiry. I outline the current and new theory that conjectures a mechanism for signal transduction based on quantum mechanical phenomena, dubbed the ‘swipe card’, which is perhaps controversial but feasible. I show that such lines of thinking may answer some questions, or at least pose the right questions. Most importantly, I draw links and comparisons as to how better understanding of how small (10’s of atoms) molecules can interact so specially with large (10 000’s of atoms) proteins in a way that is so integral to healthy living. Repercussions of this work are not just important in understanding a basic scientific tool used by us all, but often taken for granted, it is also a step closer to understanding generic mechanisms between drug and receptor, for example

Interleukin 2 activation of natural killer cells rapidly induces the expression and phosphorylation of the Leu-23 activation antigen.

IL-2 potentiates both growth and cytotoxic function of T lymphocytes and NK cells. Resting peripheral blood NK cells can respond directly to rIL-2, without requirement for accessory cells or cofactors, and enhanced cytotoxicity can be measured within a few hours after exposure to this lymphokine. In this study, we describe an activation antigen, Leu-23, that is rapidly induced and phosphorylated after IL-2 stimulation of NK cells and a subset of low buoyant density T lymphocytes. Previously, it has been uncertain whether all NK cells or only a subset are responsive to IL-2. Since within 18 h after exposure to IL-2, essentially all NK cells express Leu-23, these findings indicate that all peripheral blood NK cells are responsive to stimulation by IL-2. The Leu-23 antigen is a disulfide-bonded homodimer, composed of 24-kD protein subunits with two N-linked oligosaccharides. Appearance of this glycoprotein on NK cells is IL-2 dependent and closely parallels IL-2-induced cytotoxicity against NK-resistant solid tumor cell targets

Mechanistic analysis of an asymmetric palladium-catalyzed conjugate addition of arylboronic acids to β-substituted cyclic enones.

An asymmetric palladium-catalyzed conjugate addition reaction of arylboronic acids to enone substrates was investigated mechanistically. Desorption electrospray ionization coupled to mass spectrometry was used to identify intermediates of the catalytic cycle and delineate differences in substrate reactivity. Our findings provide evidence for the catalytic cycle proceeding through formation of an arylpalladium(II) cation, subsequent formation of an arylpalladium-enone complex, and, ultimately, formation of the new C-C bond. Reaction monitoring in both positive and negative ion modes revealed that 4-iodophenylboronic acid formed a relatively stable trimeric species under the reaction conditions

Isomorphic classical molecular dynamics model for an excess electron in a supercritical fluid

Ring polymer molecular dynamics (RPMD) is used to directly simulate the dynamics of an excess electron in a supercritical fluid over a broad range of densities. The accuracy of the RPMD model is tested against numerically exact path integral statistics through the use of analytical continuation techniques. At low fluid densities, the RPMD model substantially underestimates the contribution of delocalized states to the dynamics of the excess electron. However, with increasing solvent density, the RPMD model improves, nearly satisfying analytical continuation constraints at densities approaching those of typical liquids. In the high density regime, quantum dispersion substantially decreases the self-diffusion of the solvated electron. In this regime where the dynamics of the electron is strongly coupled to the dynamics of the atoms in the fluid, trajectories that can reveal diffusive motion of the electron are long in comparison to $\beta\hbar$.Comment: 24 pages, 4 figure

Clarification of the relationship between bound and scattering states in quantum mechanics: Application to 12C + alpha

Using phase-equivalent supersymmetric partner potentials, a general result from the inverse problem in quantum scattering theory is illustrated, i.e., that bound-state properties cannot be extracted from the phase shifts of a single partial wave, as a matter of principle. In particular, recent R-matrix analyses of the 12C + alpha system, extracting the asymptotic normalization constant of the 2+ subthreshold state, C12, from the l=2 elastic-scattering phase shifts and bound-state energy, are shown to be unreliable. In contrast, this important constant in nuclear astrophysics can be deduced from the simultaneous analysis of the l=0, 2, 4, 6 partial waves in a simplified potential model. A new supersymmetric inversion potential and existing models give C12=144500+-8500 fm-1/2.Comment: Expanded version (50% larger); three errors corrected (conversion of published reduced widths to ANCs); nine references added, one remove

Análisis molecular de los cambios evolutivos en poblaciones de Ophiostoma novo-ulmi

The spread of Ophiostoma novo-ulmi across Europe, North America and central Asia, resulted in the current, highly destructive Dutch elm disease (DED) pandemic, replacing O. ulmi, responsible for the first DED pandemic in the early 1900s. This process has resulted in a series of remarkable evolutionary and adaptive developments. Studies of O. novo- ulmi populations in the 1980s, especially in Spain and Portugal, showed the following: 1) that O. novo-ulmi initially spread across Europe as a series of genetic clones; 2) that deleterious RNA viruses were transmitted within the O. novo-ulmi clones; 3) that natural hybrids between O. novo-ulmi subspecies americana and subsp. novo-ulmi, emerged widely across Europe; 4) that there has also been a widespread emergence, across Europe, of natural hybrids between O. novo-ulmi subspecies americana and also subsp. novo-ulmi. The factors driving these changes have been examined by molecular analysis. Results show: 1) that the rapid change from clonality to genetic variability involved the acquisition of ‘useful’ mating type, vegetative compatibility type and other genes by O. novo-ulmi from O. ulmi via lateral (or interspecies) gene transfer; whereas ‘unuseful’ O. ulmi genes were discarded; 2) that the RNA viruses occurring in the O. novo-ulmi populations probably originated from O. ulmi; and 3) and that where O. novo-ulmi subsp. americana and subsp. novo-ulmi co-exist, natural hybrids are occurring very freely; in some areas most O. novo-ulmi isolates are already complex subspp. americana x novo-ulmi hybrids. These phenomena features are unique, and have considerable implications for the invasion history, successful spread and future behaviour of O. novo-ulmi.La expansión de Ophiostoma novo-ulmi en Europa, Norteamérica y Asia central provocó la actual pandemia de grafiosis, altamente destructiva, y reemplazó a O. ulmi, responsable de la primera pandemia de grafiosis a principios del siglo XX. Este proceso ha provocado una serie de destacables desarrollos evolutivos y adaptativos. Los estudios realizados en la década de 1980 en poblaciones de O. novo-ulmi, especialmente en España y Portugal, mostraron lo siguiente: 1) que inicialmente O. novo-ulmi se expandió a través de Europa como una serie de clones genéticos; 2) que virus deletéreos de RNA se trsmitieron dentro de los clones de O. novo-ulmi; 3) que híbridos naturales entre las subespecies americana y novo-ulmi de O. novo-ulmi aparecieron en muchas zonas de Europa; 4) que en toda Europa está surgiendo un gran número de híbridos naturales entre las subespecies americana y novo-ulmi de O. novo-ulmi. Los factores conducentes a estos cambios han sido examinados mediante análisis molecular. Los resultados son: 1) que el rápido paso desde una situación de clonalidad a otra con gran variabilidad genética supuso la aparición de formas «utiles» para el apareamiento, formas con compatibilidad vegetativa, y otros genes de O. novo-ulmi por transferencia lateral (o interespecífica) a partir de O. ulmi; mientras que se descartó la presencia de genes «inútiles» de O. ulmi; 2) que los virus ARN presentes en las poblaciones de O. novo-ulmi se originaron probablemente a partir de O. ulmi; y 3) que en los lugares donde O. novo-ulmi subsp. americana y subsp. novo-ulmi coexisten, los híbridos naturales se generan libremente; en algunas áreas la mayor parte de los O. novo-ulmi aislados son en realidad complejos híbridos subsp. americana x subsp. novo-ulmi. Estas características son únicas, y tiene considerable implicaciones para la historia invasora, la exitosa dispersión y el futuro comportamiento de O. novo-ulmi

Simulation and Flight Test Environments for the TASAR Traffic Aware Planner

The Traffic Aware Planner (TAP) software is a flight deck decision support tool that enhances the flight crews ability to make flight-optimizing route change requests while airborne. The software provides conflict-free, optimized trajectory suggestions during en route flight to produce time- and fuel-savings compared to the current trajectory. The TAP software requires evaluation in an operational environment with real pilot users to validate projected benefits. To this end, a set of developmental test environments have been developed to mature the software and mitigate technical risk prior to entering operational evaluation. The unique attributes of each test environment were leveraged to provide a range of purpose- and case-dependent TAP software tests. This paper describes the elements of a testing environment, discusses several environments of varying fidelity used to test the TAP software, and provides a review of two case studies highlighting the vital role testing played in the TAP software development process

Characterization of Knots and Links Arising From Site-specific Recombination on Twist Knots

We develop a model characterizing all possible knots and links arising from recombination starting with a twist knot substrate, extending previous work of Buck and Flapan. We show that all knot or link products fall into three well-understood families of knots and links, and prove that given a positive integer $n$, the number of product knots and links with minimal crossing number equal to $n$ grows proportionally to $n^5$. In the (common) case of twist knot substrates whose products have minimal crossing number one more than the substrate, we prove that the types of products are tightly prescribed. Finally, we give two simple examples to illustrate how this model can help determine previously uncharacterized experimental data.Comment: 32 pages, 7 tables, 27 figures, revised: figures re-arranged, and minor corrections. To appear in Journal of Physics

Proton induced radioactivities

Results are tabulated of the radioactivities produced by 4 Mev protons in targets of 7N, 8O, 20Ca, 24Cr, 27Co, 30Zn, 34Se, 42Mo, 46Pd, 48Cd, 49In. In most cases the reactions are of the p-n type, and lead to isotopes which emit either + or - electrons. A detailed study was made of O, Zn and Se. The reaction O18(p, n)F18 (107 min.) shows a threshold at 2.56 Mev and a positron energy of 0.74 Mev in good agreement with the energy relations. The cross section for the reaction at 4 Mev is about 2×10^-25 cm^2 and there is a resonance maximum at 3.55 Mev. The cross section for the reaction O16(p, γ)F17 is 4000 times smaller. The isomeric Br80 periods (17.4 min. and 4.45 hr.) are observed in the reaction Se80(p, n)Br80. At 4 Mev the ratio of the short to long period activities for infinite bombardment is about 15 but the thresholds are at about 3.0 and 3.2 Mev, respectively. The cross section for the reaction is about 0.6×10^-26 cm^2 at 4 Mev

Post Eruption inflation of the East Pacific Rise at 9°50′ N

In June 2008, we installed a geodetic network at 9°50′ N on the East Pacific Rise to track the long‐term movement of magma following the 2005/6 eruption. This network consists of 10 concrete benchmarks stretching from the ridge to 9 km off‐axis. During three campaign‐style surveys, measurements of vertical seafloor motions were made at each of these benchmarks by precisely recording ambient seawater pressure as a proxy for seafloor depth with a mobile pressure recorder (MPR). The MPR was deployed using the manned submersible Alvin in 2008 and 2009 and the remotely operated vehicle Jason in 2011. The MPR observations are supplemented with data from a multiyear deployment of continuously recording bottom pressure recorders (BPRs) extending along this segment of the ridge that can record rapid changes in seafloor depth from seafloor eruptions and/or dike intrusions. These measurements show no diking events and up to 12 cm of volcanic inflation that occurred from December 2009 to October 2011 in the area of the 2005/6 eruption. These observations are fit with an inflating point source at a depth of 2.7 km and volume change of 2.3 × 106 m3/yr located on the ridge axis at approximately 9°51.166′ N, 407 m from our northernmost benchmark, suggesting that the magma chamber underlying this segment of the ridge is being recharged from a deeper source at a rate that is about half the long‐term inflation rate observed at Axial Seamount on the Juan de Fuca Ridge. These data represent the second location that active volcanic uplift has been measured on a mid‐ocean ridge segment, and the first on a nonhotspot influenced segment