Anderson localization of a Tonks-Girardeau gas in potentials with controlled disorder

We theoretically demonstrate features of Anderson localization in the Tonks-Girardeau gas confined in one-dimensional (1D) potentials with controlled disorder. That is, we investigate the evolution of the single particle density and correlations of a Tonks-Girardeau wave packet in such disordered potentials. The wave packet is initially trapped, the trap is suddenly turned off, and after some time the system evolves into a localized steady state due to Anderson localization. The density tails of the steady state decay exponentially, while the coherence in these tails increases. The latter phenomenon corresponds to the same effect found in incoherent optical solitons

Significant contribution to total mass from very small glaciers

A single large glacier can contain tens of millions of times the mass of a small glacier. Nevertheless, very small glaciers (with area ≤1 km<sup>2</sup>) are so numerous that their contribution to the world's total ice volume is significant and may be a notable source of error if excluded. With current glacier inventories, total global volume errors on the order of 10% are possible. However, to reduce errors to below 1% requires the inclusion of glaciers that are smaller than those recorded in most inventories. At the global scale, 1% accuracy requires a list of all glaciers and ice caps (GIC, exclusive of the ice sheets) larger than 1 km<sup>2</sup>, and for regional estimates requires a complete list of all glaciers down to the smallest possible size. For this reason, sea-level rise estimates and other total mass and total volume analyses should not omit the world's smallest glaciers. In particular, upscaling GIC inventories has been common practice in sea level estimates, but downscaling may also be necessary to include the smallest glaciers

Inhibition of Cholinesterases by the Oximes P2AM and Toxogonin

The reversible inhibition of electric eel acetylcholinesterase (EC 3.1.1.7) by P2AM (2-(hydroxyimino)methyl-1-methyl-pyridinium chloride) and Toxogonin (1,1\u27-[oxybis(methylene)] bis(4-(hydroxyimino) methyl-pyridinium) dichloride) was studied using ac.etylthiocholine as substrate. Two techniques were applied for measuring acetylthiocholine hydrolysis, the conventional spectrophotometric and the stopped-flow (at 25 °c in 100 mM phosphate buffer pH = 7.4). The correlation between the degree of inhibition, and acetylthiocholine and oxime concentrations fits a theoretical model which postulates that the substrate and the inhibitor bind to two sites on the enzyme: the catalytic site and an allosteric, substrate-inhibition, site. The calculated dissociation constants for the two sites are: 0.13 and 0.76 mM for P2AM, and 0.16 and 2.0 mM for Toxogonin. The suggested model is an alternative to the hypothesis that two types of binding occur within the catalytic site. Horse serum cholinesterase and bovine erythrocyte acetylcholinesterase are also inhibited by P2AM and Toxogonin to about the same degree as the electric eel enzyme. Acetylthiocholine reacts with P2AM and Toxogonin; assuming that the reaction is bimolecular the corresponding rate constants are 13.4 and 22.4 M-1 min-

Navarivanje vijenaca monoblok točka (MBT) čelika R7T za željeznička vozila

The steel R7T monoblock wheel material properties are defined by the International Declaration UIC 812-3. Taking into consideration the resurfacing of the rim, the analyzed conditions for the resurfacing, as well as the analysis of the chemical compounds, mechanical characteristics (material hardness, pulling strength, and tenacity), ultrasound and metallographic testing, which proved that the resurfaced rim area has the required characteristics, according to the Declaration UIC 812-3.Svojstva materijala monobloka točkova čelika R7T su određeni po međunarodnoj objavi UIC 812-3. Na temelju navarivanja vijencaovih točkova, istraživanih uvjeta za navarivanje, te ispitivanjem kemijskog sastava, mehničkih svojstava (tvrdoće, vlačne čvrstoće, žilavosti), ultrazvučnim i metalograpskim ispitivanjima, dokazano je da navareni sloj vijenca ima osobine sukladne traženim po objavi UIC 812-3

Inhibition of Cholinesterases by the Oximes P2AM and Toxogonin

The reversible inhibition of electric eel acetylcholinesterase (EC 3.1.1.7) by P2AM (2-(hydroxyimino)methyl-1-methyl-pyridinium chloride) and Toxogonin (1,1\u27-[oxybis(methylene)] bis(4-(hydroxyimino) methyl-pyridinium) dichloride) was studied using ac.etylthiocholine as substrate. Two techniques were applied for measuring acetylthiocholine hydrolysis, the conventional spectrophotometric and the stopped-flow (at 25 °c in 100 mM phosphate buffer pH = 7.4). The correlation between the degree of inhibition, and acetylthiocholine and oxime concentrations fits a theoretical model which postulates that the substrate and the inhibitor bind to two sites on the enzyme: the catalytic site and an allosteric, substrate-inhibition, site. The calculated dissociation constants for the two sites are: 0.13 and 0.76 mM for P2AM, and 0.16 and 2.0 mM for Toxogonin. The suggested model is an alternative to the hypothesis that two types of binding occur within the catalytic site. Horse serum cholinesterase and bovine erythrocyte acetylcholinesterase are also inhibited by P2AM and Toxogonin to about the same degree as the electric eel enzyme. Acetylthiocholine reacts with P2AM and Toxogonin; assuming that the reaction is bimolecular the corresponding rate constants are 13.4 and 22.4 M-1 min-

Modelling ice dynamic contributions to sea level rise from the Antarctic Peninsula

The future ice dynamical contribution to sea-level rise (SLR) from 210 ice shelf nourishing drainage basins of the Antarctic Peninsula Ice Sheet (APIS) is simulated, using the British Antarctic Survey Antarctic Peninsula Ice Sheet Model. Simulations of the grounded ice sheet include response to ice-shelf collapse, estimated by tracking thermal ice shelf viability limits in 14 IPCC Global Climate Model ensemble temperature projections. Grounding line retreat in response to ice shelf collapse is parameterized with a new multivariate linear regression model utilizing a range of glaciological and geometric predictor variables. Multi-model means project SLR up to 9.4 mm sea-level equivalent (SLE) by 2200, and up to 19 mm SLE by 2300. Rates of SLR from individual drainage basins throughout the peninsula are similar to 2100, yet diverge between 2100 and 2300 due to individual basin characteristics. Major contributors to SLR are the outlet glaciers feeding southern George VI Ice Shelf, accounting for >75% of total SLR in some model runs. Ice sheet thinning induced by ice-shelf removal is large (up to ∼500 m), especially in Palmer Land in the Southern Antarctic Peninsula, and may propagate as far as 135 km inland. These results emphasize the importance of the ice dynamical contribution to future sea level of the APIS on decadal to centennial timescales

Imidazole aldoximes effective in assisting butyrylcholinesterase catalysis of organophosphate detoxification.

Intoxication by organophosphate (OP) nerve agents and pesticides should be addressed by efficient, quickly deployable countermeasures such as antidotes reactivating acetylcholinesterase or scavenging the parent OP. We present here synthesis and initial in vitro characterization of 14 imidazole aldoximes and their structural refinement into three efficient reactivators of human butyrylcholinesterase (hBChE) inhibited covalently by nerve agent OPs, sarin, cyclosarin, VX, and the OP pesticide metabolite, paraoxon. Rapid reactivation of OP-hBChE conjugates by uncharged and nonprotonated tertiary imidazole aldoximes allows the design of a new OP countermeasure by conversion of hBChE from a stoichiometric to catalytic OP bioscavenger with the prospect of oral bioavailability and central nervous system penetration. The enhanced in vitro reactivation efficacy determined for tertiary imidazole aldoximes compared to that of their quaternary N-methyl imidazolium analogues is attributed to ion pairing of the cationic imidazolium with Asp 70, altering a reactive alignment of the aldoxime with the phosphorus in the OP-hBChE conjugate

Thermoelectrical manipulation of nanomagnets

We investigate the interplay between the thermodynamic properties and spin-dependent transport in a mesoscopic device based on a magnetic multilayer (F/f/F), in which two strongly ferromagnetic layers (F) are exchange-coupled through a weakly ferromagnetic spacer (f) with the Curie temperature in the vicinity of room temperature. We show theoretically that the Joule heating produced by the spin-dependent current allows a spin-thermo-electronic control of the ferromagnetic-to-paramagnetic (f/N) transition in the spacer and, thereby, of the relative orientation of the outer F-layers in the device (spin-thermo-electric manipulation of nanomagnets). Supporting experimental evidence of such thermally controlled switching from parallel to antiparallel magnetization orientations in F/f(N)/F sandwiches is presented. Furthermore, we show theoretically that local Joule heating due to a high concentration of current in a magnetic point contact or a nanopillar can be used to reversibly drive the weakly ferromagnetic spacer through its Curie point and thereby exchange couple and decouple the two strongly ferromagnetic F-layers. For the devices designed to have an antiparallel ground state above the Curie point of the spacer, the associated spin-thermionic parallel-to-antiparallel switching causes magneto-resistance oscillations whose frequency can be controlled by proper biasing from essentially DC to GHz. We discuss in detail an experimental realization of a device that can operate as a thermo-magneto-resistive switch or oscillator.Comment: This paper, published in J. Appl. Phys. 107, 123706 (2010), is an expanded version of arXiv:0710.5477 (8 pages, 12 figures, two additional authors and experimental section added

Spin-thermo-electronic oscillator based on inverse giant magnetoresistance

A spin-thermo-electronic valve with the free layer of exchange-spring type and inverse magnetoresistance is investigated. The structure has S-shaped current-voltage characteristics and can exhibit spontaneous oscillations when integrated with a conventional capacitor within a resonator circuit. The frequency of the oscillations can be controlled from essentially dc to the GHz range by the circuit capacitance.Comment: 7 pages, 9 figure

Termička stabilnost silicij–ugljik amorfnih legura nanesenih magnetronskim izvorima

Amorphous a-Si0.85C0.15:H and a-Si0.6C0.4:H alloys were deposited onto a non-heated substrate using a magnetron source. The samples were exposed to a sequential iso-chronal thermal annealing up to 1000 ° C in a vacuum chamber, and were investigated by the IR spectroscopy and X-ray diffraction measurements. The influence of the thermal treatment on structural ordering was monitored by the evolution of the intensity and shape of the spectral IR lines corresponding to the Si-H and Si-C bonds. At low temperatures, the most pronounced features were accompanied with hydrogen evolution which completes up to 400 ° C. Up to 800 ° C the Si-C absorption lines have gradually changed their shape, peak position and intensity. At 900 ° C, the abrupt changes occured, denoting final transition to crystalline state.Slojevi amorfnog a−Si0.85C0.15:H i a−Si0.6C0.4:H su formirani magnetronskim izvorom, na nezagrijanoj podlozi. Nakon depozicije, uzorci su postepeno grijani u vakuumu do 1000 ◦C. Između uzastopnih grijanja vršena su mjerenja infra–crvenom spektroskopijom i difrakcijom X-zraka. Utjecaj ovakvog termalnog tretmana na strukturno uređenje uzoraka je praćeno razvojem intenziteta i oblika spektralnih linija koje odgovaraju Si−H i Si−C vezama. Na nižim temperaturama, najizrazitije promjene su vezane za desorpciju vodika, koja završava do 400 ◦C. Daljnjim grijanjem do 800 ◦C, linije postepeno mijenjaju oblik, intenzitet i frekvenciju maksimuma. Grijanje na i iznad 900 ◦C uzrokuje nagle promjene, označavajući prijelaz u kristalinično stanje