The Effects of Turbulence on Three-Dimensional Magnetic Reconnection at the Magnetopause

Two- and three-dimensional particle-in-cell simulations of a recent encounter of the Magnetospheric Multiscale Mission (MMS) with an electron diffusion region at the magnetopause are presented. While the two-dimensional simulation is laminar, turbulence develops at both the x-line and along the magnetic separatrices in the three-dimensional simulation. The turbulence is strong enough to make the magnetic field around the reconnection island chaotic and produces both anomalous resistivity and anomalous viscosity. Each contribute significantly to breaking the frozen-in condition in the electron diffusion region. A surprise is that the crescent-shaped features in velocity space seen both in MMS observations and in two-dimensional simulations survive, even in the turbulent environment of the three-dimensional system. This suggests that MMS's measurements of crescent distributions do not exclude the possibility that turbulence plays an important role in magnetopause reconnection.Comment: Revised version accepted by GR

Gelatin-Sealed Dacron Graft is not more Susceptible to MRSA Infection than PTFE Graft

ObjectivesThe purpose of this experimental study was to compare the susceptibility of gelatin-sealed Dacron and PTFE prostheses to infection by MRSA.DesignProspective, randomized, controlled animal study.Materials and MethodsGraft infections were established in the subcutaneous tissues of 60 female Spraque-Dawley rats by the implantation of gelatin-sealed Dacron or PTFE prostheses followed by topical inoculation with methicillin-resistant Staphylococcus aureus. The study groups were as follows: (1A) uncontaminated gelatin-sealed Dacron group, (1B) untreated contaminated gelatin-sealed Dacron group, (1C) contaminated gelatin-sealed Dacron group with intraperitoneal teicoplanin treatment, (2A) uncontaminated PTFE group, (2B) untreated contaminated PTFE group, and (2C) contaminated PTFE group with intraperitoneal teicoplanin treatment. The grafts were removed after 7 days and evaluated for infection by counting the number of adherent bacteria on the graft material after rinsing and sonication. The perigraft tissue was harvested for histopathological study. To investigate the existence of any infection, blood samples were collected by cardiopuncture for a culture analysis.ResultsNo significant difference in bacteria counts was observed between gelatin-sealed Dacron and PTFE grafts. In groups 1A and 2A, there was no infection detected. The bacterial counts for MRSA were 7.4×105 in group 1B and 8.6×105 in group 2B. There was also no infection in groups 1C and 2C. While the difference between group 1B and 2B was not significant (p>.05), bacterial counts in group 1B or 2B were significantly higher than those in other groups. Blood cultures were only positive in four rats in group 1B and in two rats in group 2B. The severities of the inflammation of the perigraft tissues was low in groups 1A and 2A, high in groups 1C and 2C, and between the range from low to moderate in groups 1B and 2B.ConclusionThe susceptibility of gelatin-sealed Dacron to bacterial infection was not higher than that of PTFE

Fundamental length in quantum theories with PT-symmetric Hamiltonians II: The case of quantum graphs

Manifestly non-Hermitian quantum graphs with real spectra are introduced and shown tractable as a new class of phenomenological models with several appealing descriptive properties. For illustrative purposes, just equilateral star-graphs are considered here in detail, with non-Hermiticities introduced by interactions attached to the vertices. The facilitated feasibility of the analysis of their spectra is achieved via their systematic approximative Runge-Kutta-inspired reduction to star-shaped discrete lattices. The resulting bound-state spectra are found real in a discretization-independent interval of couplings. This conclusion is reinterpreted as the existence of a hidden Hermiticity of our models, i.e., as the standard and manifest Hermiticity of the underlying Hamiltonian in one of less usual, {\em ad hoc} representations ${\cal H}_j$ of the Hilbert space of states in which the inner product is local (at $j=0$) or increasingly nonlocal (at $j=1,2, ...$). Explicit examples of these (of course, Hamiltonian-dependent) hermitizing inner products are offered in closed form. In this way each initial quantum graph is assigned a menu of optional, non-equivalent standard probabilistic interpretations exhibiting a controlled, tunable nonlocality.Comment: 33 pp., 6 figure

Physicochemical Factors on The Hydrolysis of Dipyrone

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109863/1/cptclpt2003194.pd

Efficacy of Vancomycin, Teicoplanin and Fusidic Acid as Prophylactic Agents in Prevention of Vascular Graft Infection: An Experimental Study in Rat

AbstractObjectivesTo compare the efficacy of a single prophylactic dose of intra-peritoneal vancomycin and teicoplanin with anti-biotic treated Dacron grafts (vancomycin, teicoplanin, 10 or 40% fusidic acid-soaked grafts) in preventing vascular graft infections in a rat model.DesignProspective, randomized, controlled animal study.Materials and methodsThe graft infections were established in the subcutaneous tissues of 80 female Sprague–Dawley rats by the implantation of Dacron prostheses followed by the topical inoculation with methicillin-resistant Staphylococcus aureus. The study groups were as follows: (1) uncontaminated control group, (2) untreated contaminated group, (3) contaminated group with intra-peritoneal vancomycin, (4) contaminated group with intra-peritoneal teicoplanin, (5) contaminated group received vancomycin-soaked Dacron graft, (6) contaminated group received teicoplanin-soaked Dacron graft, (7) contaminated group received 40% fusidic acid-soaked Dacron graft, and (8) contaminated group received 10% fusidic acid-soaked Dacron graft prophylaxis. The grafts were removed after 7 days and evaluated by a quantitative culture analysis.ResultsNo infection was detected in controls. The untreated contaminated group had a high bacteria count (6.0×104CFU/cm2 Dacron graft). Groups that received intra-peritoneal vancomycin or teicoplanin had less bacterial growth (4.8×103 and 3.9×103CFU/cm2 Dacron graft, respectively). Similarly, the group that received 10% fusidic acid-soaked graft showed less bacterial growth (3.6×103CFU/cm2 Dacron graft). The groups with vancomycin-, teicoplanin- and 40% fusidic acid-soaked grafts showed no evidence of infection. Statistical analyses demonstrated that intra-peritoneal prophylactic antibiotic treatment was less effective in inhibiting bacterial growth than high concentration antimicrobial-soaking of grafts.ConclusionThe use of vancomycin-, teicoplanin- and 40% fusidic acid-soaked grafts was effective in preventing primary prosthetic vascular graft infection

Observations of whistler mode waves with nonlinear parallel electric fields near the dayside magnetic reconnection separatrix by the Magnetospheric Multiscale mission

We show observations from the Magnetospheric Multiscale (MMS) mission of whistler mode waves in the Earth's low-latitude boundary layer (LLBL) during a magnetic reconnection event. The waves propagated obliquely to the magnetic field toward the X line and were confined to the edge of a southward jet in the LLBL. Bipolar parallel electric fields interpreted as electrostatic solitary waves (ESW) are observed intermittently and appear to be in phase with the parallel component of the whistler oscillations. The polarity of the ESWs suggests that if they propagate with the waves, they are electron enhancements as opposed to electron holes. The reduced electron distribution shows a shoulder in the distribution for parallel velocities between 17,000 and 22,000 km/s, which persisted during the interval when ESWs were observed, and is near the phase velocity of the whistlers. This shoulder can drive Langmuir waves, which were observed in the high-frequency parallel electric field data

On deformation of electron holes in phase space

This Letter shows that for particularly shaped background particle distributions momentum exchange between phase space holes and the distribution causes acceleration of the holes along the magnetic field. In the particular case of a non-symmetric ring distribution (ring with loss cone) this acceleration is nonuniform in phase space being weaker at larger perpendicular velocities thus causing deformation of the hole in phase space.Comment: Original MS in EPL style, 1 Figur

Pattern Matching in Multiple Streams

We investigate the problem of deterministic pattern matching in multiple streams. In this model, one symbol arrives at a time and is associated with one of s streaming texts. The task at each time step is to report if there is a new match between a fixed pattern of length m and a newly updated stream. As is usual in the streaming context, the goal is to use as little space as possible while still reporting matches quickly. We give almost matching upper and lower space bounds for three distinct pattern matching problems. For exact matching we show that the problem can be solved in constant time per arriving symbol and O(m+s) words of space. For the k-mismatch and k-difference problems we give O(k) time solutions that require O(m+ks) words of space. In all three cases we also give space lower bounds which show our methods are optimal up to a single logarithmic factor. Finally we set out a number of open problems related to this new model for pattern matching.Comment: 13 pages, 1 figur

MYOMECTOMY DURING CESAREAN SECTION AND ADHESION FORMATION AS A LONG-TERM POSTOPERATIVE COMPLICATION

Objectives: We aimed to evaluate the incidence and features of postoperative adhesion related complications occurring following myolysis or myomectomy performed during cesarean section (C/S). Methods: This cross-sectional study consists of four groups of patients who underwent C/S: group I; myolysis is performed by electric cauterization for small superficial fibroids less than 2 cm. (n: 21), group II; myomectomy is performed for pedunculated fibroids (n: 18), group III; myomectomy is performed for intramural/subserous fibroids less than 5 cm. (n: 23), group IV; control group (n: 19) who did not go through myomectomy. Repeat C/S is performed to study subjects within 1-5 years. All cases are evaluated in terms of mild to moderate adhesions between omentum and uterus, mild to moderate adnexial area adhesions, mild to moderate incision area adhesions and surgical difficulty due to severe adhesions. Results: The incidence of adhesions of omentum and uterus (p= 0.278), mild to moderate adnexial area adhesions (p= 0.831), mild to moderate incision area adhesions (p= 0.804) were similar between the intervention groups (group I, II, and III) and the controls (group IV). Conclusion: Cesarean myomectomy is a safe procedure and can be performed without significant postoperative adhesion formation.Cel pracy: Celem naszego badania była ocena częstości występowania i charakter zrostów pooperacyjnych po zabiegu miolizy lub miomektomii w trakcie cięcia cesarskiego. Metoda: Do badania włączono cztery grupy pacjentek, które miały wykonane cięcie cesarskie (C/S) oraz miolizę powierzchniowego, mniejszego niż 2cm mięśniaka metodą elektrokauteryzacji – grupa I (n:21), usunięcie mięśniaka uszypułowanego – grupa II (n:18), miomektomię mięśniaka wewnątrzściennego/podsurowicówkowego, mniejszego niż 5 cm – grupa III (n:23), nie miały wykonanej miomektomii – grupa IV kontrolna (n:19). Ponowne cięcie cesarskie wykonano u badanych pacjentek w ciągu 1-5 lat. Wszystkie pacjentki oceniono pod kątem małych do średnich zrostów pomiędzy siecią większą i macicą, małych do średnich zrostów w okolicy przydatków, małych do średnich zrostów w okolicy nacięcia powłok i trudności operowania z powodu ciężkich zrostów. Wyniki: Częstość występowania zrostów pomiędzy otrzewną i macicą (p=0,278), małych do średnich zrostów w okolicy przydatków (p=0,831), małych do średnich zrostów w okolicy nacięcia powłok (p=0,804) była podobna pomiędzy badanymi grupami (I,II i III) a grupą kontrolną (IV). Wnioski: Miomektomia podczas cięcia cesarskiego jest bezpieczną procedurą i może być przeprowadzana bez istotnych, pooperacyjnych zrostów