Measuring clock jumps using pulsar timing

The Giant Radio Array for Neutrino Detection(GRAND) is a planned large-scale observatory of ultra-high-energy(UHE) cosmic particles, with energies exceeding 10~8 Ge V. Its goal is to solve the long-standing mystery of the origin of UHE cosmic rays. To do this, GRAND will detect an unprecedented number of UHE cosmic rays and search for the undiscovered UHE neutrinos and gamma rays associated to them with unmatched sensitivity. GRAND will use large arrays of antennas to detect the radio emission coming from extensive air showers initiated by UHE particles in the atmosphere. Its design is modular: 20 separate, independent sub-arrays, each of 10000 radio antennas deployed over 10000 km~2. A staged construction plan will validate key detection techniques while achieving important science goals early. Here we present the science goals, detection strategy, preliminary design, performance goals, and construction plans for GRAND.     

Iodide‐Induced Shuttling of a Halogen‐ and Hydrogen‐Bonding Two‐Station Rotaxane

The first example of utilizing halogen‐bonding anion recognition to facilitate molecular motion in an interlocked structure is described. A halogen‐bonding and hydrogen‐bonding bistable rotaxane is prepared and demonstrated to undergo shuttling of the macrocycle component from the hydrogen‐bonding station to the halogen‐bonding station upon iodide recognition. In contrast, chloride‐anion binding reinforces the macrocycle to reside at the hydrogen‐bonding station.     

Plane brownian motion in a region with holes

We consider a fixed family of balls with decreasing radii in the plane. We establish a relationship between a Dirichlet problem in a region without the balls and the solution of a Schroedinger equation in the complete region. Then we find upper bounds for the probability that a brownian motion exits the region without touching these balls. This is used to study harmonic measure and entire functions.     

ALS-associated mutant SOD1<Superscript>G93A</Superscript> causes mitochondrial vacuolation by expansion of the intermembrane space and by involvement of SOD1 aggregation and peroxisomes

Background  

Amyotrophic lateral sclerosis (ALS) is an age-dependent neurodegenerative disease that causes motor neuron degeneration, paralysis and death. Mutations in Cu, Zn superoxide dismutase (SOD1) are one cause for the familial form of this disease. Transgenic mice expressing mutant SOD1 develop age-dependent motor neuron degeneration, skeletal muscle weakness, paralysis and death similar to humans. The mechanism whereby mutant SOD1 induces motor neuron degeneration is not understood but widespread mitochondrial vacuolation has been observed during early phases of motor neuron degeneration. How this vacuolation develops is not clear, but could involve autophagic vacuolation, mitochondrial permeability transition (MPT) or uncharacterized mechanisms. To determine which of these possibilities are true, we examined the vacuolar patterns in detail in transgenic mice expressing mutant SOD1^G93A.     

Sidelobe decline in single-photon 4Pi microscopy by Toraldo rings

We demonstrate theoretically the feasibility of single-photon 4Pi-confocal microscopy. By inserting a pair of properly designed multi-ring phase-only pupil filters in the illumination path of a 4Pi microscope the height of the sidelobes of the point spread function substantially reduced, so that there is no ambiguity in the 3D image. Then, an axial resolution up to four times higher than that of single-photon confocal microscope can be effectively achieved.     

Dichlorocarbene Addition to

In contrast to the terminal phosphinidene complex PhPW(CO)(5) (2), which adds to [5]metacyclophane (1) in a 1,4-fashion, dichlorocarbene preferentially adds in a 1,2-fashion to the formal "anti-Bredt" type double bond of the aromatic ring of 1 to afford the norcaradiene 11b, which immediately rearranges to the bridged cycloheptatriene 12b and further by a [1,5] sigmatropic chlorine migration to the isomeric 13b as the first observable product. More slowly, the latter isomerizes via a dissociative mechanism to give 15b. A computational study supports the notion that the [1,5] chlorine migration in the rearrangement 12b --> 13b, for which an activation barrier of 70.2 kJ mol(-)(1) was calculated, is essentially concerted with minor charge separation. In contrast, the analogous [1,5] chlorine migration in the flat model compound 7,7-dichlorocycloheptatriene (12a) displays features of a dissociative pathway.     

List of Contributors

Authors Index

List of Contributors     

Synthesis and Characterization of Ethylene/Propylene Copolymers in the Whole Composition Range

Summary: The incorporation of comonomer molecules in the backbone of a homopolymer can influence the final properties of the material, decreasing its crystallinity and the melting and glass transition temperatures, and increasing its impact resistance and transparency. In the present work, ten ethylene/propylene copolymers have been synthesized using a supported metallocene catalytic system covering the whole composition range. Any desired composition was obtained by controlling the feed composition during the reaction. These synthesized copolymers have been characterized by different techniques in order to study the effect of the comonomer incorporation onto their final properties. When the comonomer content is low, the behaviour of the copolymer is similar to that of the corresponding homopolymer. Nevertheless, if the comonomer content increases, the copolymer becomes more amorphous (low crystallization temperature and soft XRD signals) and easily deformable, reaching a behaviour close to that corresponding to an elastomeric material. In order to corroborate these results the samples have been characterized by TREF and GPC-MALS. TREF analysis showed that copolymers containing less than 10% and more than 80% of ethylene are semicrystalline, with elution temperatures typical of this kind of polymers. Molecular weights are higher for homopolymers and they decrease as the comonomer concentration increases, whereas the polydispersity index keeps almost constant at the expected value for this kind of samples.