Giant suppression of the Drude conductivity due to quantum interference in disordered two-dimensional systems

Temperature and magnetic field dependences of the conductivity in heavily doped, strongly disordered two-dimensional quantum well structures GaAs/In$_x$Ga$_{1-x}$As/GaAs are investigated within wide conductivity and temperature ranges. Role of the interference in the electron transport is studied in the regimes when the phase breaking length $L_\phi$ crosses over the localization length $\xi\sim l\exp{(\pi k_Fl/2)}$ with lowering temperature, where $k_F$ and $l$ are the Fermi quasimomentum and mean free path, respectively. It has been shown that all the experimental data can be understood within framework of simple model of the conductivity over delocalized states. This model differs from the conventional model of the weak localization developed for $k_Fl\gg 1$ and $L_\phi\ll\xi$ by one point: the value of the quantum interference contribution to the conductivity is restricted not only by the phase breaking length $L_\phi$ but by the localization length $\xi$ as well. We show that just the quantity $(\tau_\phi^\ast)^{-1}=\tau_\phi^{-1}+\tau_\xi^{-1}$ rather than $\tau_\phi^{-1}$, where $\tau_\phi\propto T^{-1}$ is the dephasing time and $\tau_\xi\sim\tau\exp(\pi k_F l)$, is responsible for the temperature and magnetic field dependences of the conductivity over the wide range of temperature and disorder strength down to the conductivity of order $10^{-2} e^2/h$.Comment: 11 pages, 15 figure

Management of the antibiotic resistance problem – approach of the Dutch Working Party on Antibiotic Policy

Zadnjih nekoliko desetljeća svjedoci smo konstantno rastućeg problema antimikrobne rezistencije zbog kojeg je Vijeće Europske Unije donijelo rezoluciju te preporuke o razumnoj uporabi antibiotika u humanoj medicini. Naglasak u preporukama je stavljen na uspostavljanje mreže praćenja antimikrobne rezistencije te implementiranje mjera za doprinos razumnoj potrošnji antibiotika kroz razvijanje nacionalnih smjernica o upotrebi antibiotika. Uspostava interdisciplinarnog nacionalnog tijela (ICM, od engl. interdisciplinary coordinating mechanism) za koordiniranje svih aktivnosti na području rezistencije bakterija na antibiotike predložena je kao glavni instrument implementacije preporuka. Kao ICM u Nizozemskoj je osnovana Radna grupa za antimikrobnu strategiju (SWAB), a u Hrvatskoj Interdisciplinarna sekcija za kontrolu rezistencije na antibiotike (ISKRA). Dobra suradnja između SWAB-a i ISKRA-e započeta je kroz Matra (Matra Pre-Accession Programme, MPAP) projekt "Praćenje antimikrobne rezistencije u humanoj medicini" nizozemskog Ministarstva vanjskih poslova. Nizozemska je zemlja s najnižom potrošnjom antibiotika u Europi te niskim udjelom antibiotske rezistencije kod većine bakterija. Rezistencija na neke antibiotike, ipak, raste.In the past decades we are witnessing an increasing antibiotic resistance problem to which the EU Ministers of Health responded by issuing a "Council Recommendation on the prudent use of antimicrobial agents in human medicine" with the recommendation of establishing antimicrobial resistance surveillance systems and implementing measures to support the prudent use of antibiotics by setting evidence based guidelines. Intersectoral Coordinating Mechanisms (ICM) at national levels have been suggested as instruments of implementation. Consequently the Working Party on Antibiotic Policy (SWAB) was founded in the Netherlands, and the Interdisciplinary Section for Antibiotic Resistance Control (ISKRA) in Croatia. Good colaboration between the SWAB and the ISKRA started through the Matra Pre-Accession Programme (MPAP) project "Antimicrobial resistance surveillance in human medicine" of the Dutch Ministry of Foreign Affairs. The Netherlands is the country with the lowest antibiotic consumption in Europe and with low antibiotic resistance rates in the majority of pathogens. However, resistance to some antibiotics is rising

Unwind: Interactive Fish Straightening

The ScanAllFish project is a large-scale effort to scan all the world's 33,100 known species of fishes. It has already generated thousands of volumetric CT scans of fish species which are available on open access platforms such as the Open Science Framework. To achieve a scanning rate required for a project of this magnitude, many specimens are grouped together into a single tube and scanned all at once. The resulting data contain many fish which are often bent and twisted to fit into the scanner. Our system, Unwind, is a novel interactive visualization and processing tool which extracts, unbends, and untwists volumetric images of fish with minimal user interaction. Our approach enables scientists to interactively unwarp these volumes to remove the undesired torque and bending using a piecewise-linear skeleton extracted by averaging isosurfaces of a harmonic function connecting the head and tail of each fish. The result is a volumetric dataset of a individual, straight fish in a canonical pose defined by the marine biologist expert user. We have developed Unwind in collaboration with a team of marine biologists: Our system has been deployed in their labs, and is presently being used for dataset construction, biomechanical analysis, and the generation of figures for scientific publication

Hands to oars: Aeschylus’ cosmo-phthoric spin on Empedocles’ whirlpool

As verso to the obverse of the gorgonic gaze of Iphigeneia ‘written’ in the fixed, all-apparent graphais in the Artemisian sacrifice, this study unfolds in the doxic Aphrodesian register the dynamics of Helen’s disembodied opsis, her image, that crosses both into Menelaus’ psyche and out through the hands of the warriors put to oars. Empedocles’ optics are argued to constitute a visual ray between viewer and object joined in the metaphorical grasping of hands. This grasping figures simultaneously metaphorical hands within Menelaus’ mind through which the opsis passes into unconsciousness and the physical hands put to oars. Menelaus’ pothos, longing, for Helen, drives the Trojan debacle as the vortex of Aeschylus’ cosmo-phthoric, cosmos-destroying, spin on Empedocles’ cosmogonic whirlpool of Aprhrodite and Ares. Aeschylus’ pathways, keleuthoi, on which the opsis moves in the register of doxein, contrast Empedocles’ pathways of the generations of forms in that of idein, and figure finally beneath the tapestries Agamemnon treads. In Aeschylus’ construction of the novel advent of proto imagination, that is, of the inward experience of the untethered image, the self-reflection of the auditor-spectator is instantiated as that of a bracketed, suspended [I] and is invoked there in the theatron to cycle between, on the diegetic level, the all-destroying vortex, on the dramaturgic mimetic level, the discharging of the dionysiac thrall in the dawning awareness of the illusion of the Gesamtwerk of Tragedy. The suspension of the dionysiac thrall reveals the ungrounded underpinning of Kierkegaard’s teleological suspension of the ethical as the abyssal [I] whence the movement of faith would spring up. Subtending then the singularity of Abraham, Knight of Faith, is the bracketed [I] shaken loose from the dæmonic tyranny of the symbolic order in the suspension of the unmediated commandment of the pagan gods as divine sanction of the sacrifice and the ethical universal.First author draf

Face values: Fargo on second look

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