Amorphous thin film growth: theory compared with experiment

Experimental results on amorphous ZrAlCu thin film growth and the dynamics of the surface morphology as predicted from a minimal nonlinear stochastic deposition equation are analysed and compared. Key points of this study are (i) an estimation procedure for coefficients entering into the growth equation and (ii) a detailed analysis and interpretation of the time evolution of the correlation length and the surface roughness. The results corroborate the usefulness of the deposition equation as a tool for studying amorphous growth processes.Comment: 7 pages including 5 figure

Colossal Effects in Transition Metal Oxides Caused by Intrinsic Inhomogeneities

The influence of quenched disorder on the competition between ordered states separated by a first-order transition is investigated. A phase diagram with features resembling quantum-critical behavior is observed, even using classical models. The low-temperature paramagnetic regime consists of coexisting ordered clusters, with randomly oriented order parameters. Extended to manganites, this state is argued to have a colossal magnetoresistance effect. A scale T* for cluster formation is discussed. This is the analog of the Griffiths temperature, but for the case of two competing orders, producing a strong susceptibility to external fields. Cuprates may have similar features, compatible with the large proximity effect of the very underdoped regime.Comment: 4 pages, 4 figure

Altitude variation of ion composition in the midlatitude trough region - Evidence for upward plasma flow

Altitude effect on ion concentration in midlatitude trough and plasmaspher

Wigner crystallization in Na(3)Cu(2)O(4) and Na(8)Cu(5)O(10) chain compounds

We report the synthesis of novel edge-sharing chain systems Na(3)Cu(2)O(4) and Na(8)Cu(5)O(10), which form insulating states with commensurate charge order. We identify these systems as one-dimensional Wigner lattices, where the charge order is determined by long-range Coulomb interaction and the number of holes in the d-shell of Cu. Our interpretation is supported by X-ray structure data as well as by an analysis of magnetic susceptibility and specific heat data. Remarkably, due to large second neighbor Cu-Cu hopping, these systems allow for a distinction between the (classical) Wigner lattice and the 4k_F charge-density wave of quantum mechanical origin.Comment: 4 pages, 4 figure

Nature's Autonomous Oscillators

Nonlinearity is required to produce autonomous oscillations without external time dependent source, and an example is the pendulum clock. The escapement mechanism of the clock imparts an impulse for each swing direction, which keeps the pendulum oscillating at the resonance frequency. Among nature's observed autonomous oscillators, examples are the quasi-biennial oscillation and bimonthly oscillation of the Earth atmosphere, and the 22-year solar oscillation. The oscillations have been simulated in numerical models without external time dependent source, and in Section 2 we summarize the results. Specifically, we shall discuss the nonlinearities that are involved in generating the oscillations, and the processes that produce the periodicities. In biology, insects have flight muscles, which function autonomously with wing frequencies that far exceed the animals' neural capacity; Stretch-activation of muscle contraction is the mechanism that produces the high frequency oscillation of insect flight, discussed in Section 3. The same mechanism is also invoked to explain the functioning of the cardiac muscle. In Section 4, we present a tutorial review of the cardio-vascular system, heart anatomy, and muscle cell physiology, leading up to Starling's Law of the Heart, which supports our notion that the human heart is also a nonlinear oscillator. In Section 5, we offer a broad perspective of the tenuous links between the fluid dynamical oscillators and the human heart physiology

Hyperbaric oxygen therapy (HBO) for the treatment of an epidural abscess in the posterior fossa in an 8-month-old infant

Epidural abscesses in children are extremely rare, especially in the posterior fossa. In some cases antibiotic therapy and surgical drainage are insufficient for complete healing. We present the case of an 8-month-old boy who developed an epidural abscess in the posterior fossa after repeated surgical procedures for retrocerebellar arachnoid cysts and hydrocephalus. We decided to use adjuvant hyperbaric oxygen therapy (HBO) to avoid removal of the bone and the existing ventriculoperitoneal shunt. In this way osteomyelitis, potentially leading to bone removal and shunt infection, could be prevented. HBO is a relatively safe, noninvasive and cost-effective therapy to improve healing of chronic and deep-seated wound infections. To our knowledge HBO has never been used before in such a young child in neurosurgery. Multidisciplinary management is recommended to optimize treatment

Pädiatrisches stumpfes thorakoabdominales Trauma: Damage-Control-Resuscitation-Therapie

Zusammenfassung: Die Primärversorgung von Kindern mit schwerem stumpfem Bauchtrauma und begleitender Azidose, Koagulopathie und Hypothermie (letale Trias) erfordert ein effizientes multidisziplinäres Therapieregime zur Reduktion der Mortalität. Ein 5,5Jahre alter Junge wurde auf einem Bergbauernhof zwischen Traktorhinterrad und Hoftorumrandung im Torsobereich eingequetscht. Es kam zu einer Milzruptur Grad IV, einer Leberruptur Grad III, einer Pankreaslazeration Grad III, einer beidseitigen Lungenkontusion und einem begleitenden Weichteiltrauma mit Rhabdomyolyse. Aufgrund des schweren Traumas mit Auftreten einer Koagulopathie und einer kombinierten metabolisch-respiratorischen Azidose erfolgten die Gabe von Blutprodukten anstelle der von Kristalloiden, Akzeptanz einer permissiven Hypotension, Stabilisierung der Körpertemperatur im Sinne einer Damage-Control-Resuscitation-Strategie sowie eine Milz erhaltende operative Versorgung mittels Laparotomie. Es wird ein mögliches Therapieregime für das pädiatrische schwere Trauma mit Massentransfusion (MT) diskutier

Effect of inhomogeneity on s-wave superconductivity in the attractive Hubbard model

Inhomogeneous s-wave superconductivity is studied in the two-dimensional, square lattice attractive Hubbard Hamiltonian using the Bogoliubov-de Gennes (BdG) mean field approximation. We find that at weak coupling, and for densities mainly below half-filling, an inhomogeneous interaction in which the on-site interaction $U_i$ takes on two values, $U_i=0, 2U$ results in a larger zero temperature pairing amplitude, and that the superconducting $T_c$ can also be significantly increased, relative to a uniform system with $U_i=U$ on all sites. These effects are observed for stripe, checkerboard, and even random patterns of the attractive centers, suggesting that the pattern of inhomogeneity is unimportant. Monte Carlo calculations which reintroduce some of the fluctuations neglected within the BdG approach see the same effect, both for the attractive Hubbard model and a Hamiltonian with d-wave pairing symmetry.Comment: 5 pages, 4 figure