On number fields with nontrivial subfields

What is the probability for a number field of composite degree $d$ to have a nontrivial subfield? As the reader might expect the answer heavily depends on the interpretation of probability. We show that if the fields are enumerated by the smallest height of their generators the probability is zero, at least if $d>6$. This is in contrast to what one expects when the fields are enumerated by the discriminant. The main result of this article is an estimate for the number of algebraic numbers of degree $d=e n$ and bounded height which generate a field that contains an unspecified subfield of degree $e$. If $n>\max\{e^2+e,10\}$ we get the correct asymptotics as the height tends to infinity

How much money can be saved by applying intravenous antibiotics once instead of several times a day?

Background: The preparation, administration and monitoring of intravenous (IV) applications are time consuming and require human resources. We estimated the potential time and cost savings by replacing antibiotics given 3-4 times daily with antibiotics with similar spectrum and efficacy given once daily. Methods: The savings of indirect costs were estimated based on the antibiotic consumption data of a two-year period (i.e. 2007 and 2008), a nurse's mean workload per application and the average nurse's salary in Switzerland. Results: The consumption of IV antibiotics in 2007 and 2008 at the University Hospital of Basel was 29.0 and 32.2 defined daily doses (DDD) per 100 patient days, respectively. Nurses spent an estimated 13,786h on the application of the estimated 82,715 does of IV antibiotics. A total of 56,404 applications or nursing staff time costs of 338,436 Swiss Francs (CHF; 236,669 €), equal to 16% of the overall costs spent on purchasing antibiotics in the year 2008, may have been saved by switching multiple-dose antibiotics to a hypothetical once-daily antibiotic. Including disposable materials, 21% or 456,884 CHF (319,499 €) could be saved annually (purchase costs not taken into account). Conclusion: We found a potential cost saving of 21% of the purchase costs in a 750-bed institution. Hence, indirect costs should be included in the calculation of the total cost for the application of broad-spectrum IV antibiotics. Switching from a 3-4 times daily application to a once-daily antibiotic should be considered if a once-daily antibiotic is deemed equally effective and has a similar spectru

Canonical Representatives of Morphic Permutations

An infinite permutation can be defined as a linear ordering of the set of natural numbers. In particular, an infinite permutation can be constructed with an aperiodic infinite word over $\{0,\ldots,q-1\}$ as the lexicographic order of the shifts of the word. In this paper, we discuss the question if an infinite permutation defined this way admits a canonical representative, that is, can be defined by a sequence of numbers from [0, 1], such that the frequency of its elements in any interval is equal to the length of that interval. We show that a canonical representative exists if and only if the word is uniquely ergodic, and that is why we use the term ergodic permutations. We also discuss ways to construct the canonical representative of a permutation defined by a morphic word and generalize the construction of Makarov, 2009, for the Thue-Morse permutation to a wider class of infinite words.Comment: Springer. WORDS 2015, Sep 2015, Kiel, Germany. Combinatorics on Words: 10th International Conference. arXiv admin note: text overlap with arXiv:1503.0618

Verwendungsraten von Prothesen der unteren Extremität in Deutschland und der Schweiz: Ein Vergleich der Jahre 2005-2008

Zusammenfassung: Hintergrund: In den USA hat die Verwendung der totalen Hüftprothese innerhalb der letzten Dekade stark zugenommen. Es ist jedoch nicht bekannt, ob sich dieser Trend auf andere Länder übertragen lässt. Ziel dieser Untersuchung war daher der detaillierte Vergleich der Verwendungsraten von Hüft-, Knie- und OSG-Prothesen in der BRD und der Schweiz im Zeitraum 2005-2008 und ein Sekundärvergleich mit den USA. Patienten und Methoden: Aus Daten der beiden statistischen Bundesämter wurden die Einwohnerzahl, Geschlechts- und Altersverteilung sowie die Anzahl von Primär- und Revisionseingriffen ermittelt. Aus diesen Kennzahlen konnte die Anzahl von Primär-, Revisions- und Gesamteingriffen, der Revisionslast, von Primär- und Revisionsraten pro 100.000 Einwohner und Jahr sowie geschlechts- und altersspezifische Primär- und Revisionsraten berechnet werden. Ein im Vergleich dazu reduzierter Datensatz aus den USA stammt direkt vom Autor der entsprechenden Auswertungen. Ergebnisse: In Deutschland, der Schweiz und den USA stieg die Anzahl der Voll- und Teilhüftprothesenimplantationen pro 100.000 Personen von 235,8, 238,2 und 116,8 im Jahr 2005 auf 254,7, 262,7 und 127,3 an. Für Voll- und Teilknieprothesen lagen die Raten bei 156,3, 140,1 und 178,2 Implantationen in 2005 und 188,3, 176,8 und 213,6 in 2008. Die Revisionslast für Hüftprothesen lag in der BRD in 2005 mit 13,6% um 3,6% höher als in der Schweiz und betrug 11,2% in den USA. In 2008 lag sie mit 15,1% um 4,6% höher als in der Schweiz und betrug wiederum 11,2% in den USA. Für Knieprothesen lag die Last in der BRD in 2005 bei 11,1% und damit 3,5% höher als in der Schweiz; in den USA betrug sie 7,4%. In 2008 lag sie bei 12,8% und somit 4,2% höher als in der Schweiz und betrug 8,9% in den USA. In allen 3 Ländern lag die Revisionslast für Knieprothesen stets unter derjenigen für Hüftprothesen. Schlussfolgerung: In allen 3 Ländern stiegen die Primärraten für Hüft- und Knieprothesen an, diejenigen für Knieprothesen stärker. Die Revisionslasten lagen in 2008 für beide Prothesentypen in der BRD am höchsten. In der Schweiz gab es eine vorübergehende Senkung der Revisionslasten und erst ab 2007 wieder einen Anstieg. Die Verwendungsrate von Hüftprothesen pro 100.000 Einwohner lag in den USA stark unter den Raten der BRD und der Schweiz, für Knieprothesen lag sie leicht darübe

Are there localized saddles behind the heterogeneous dynamics of supercooled liquids?

We numerically study the interplay between heterogeneous dynamics and properties of negatively curved regions of the potential energy surface in a model glassy system. We find that the unstable modes of saddles and quasi-saddles undergo a localization transition close to the Mode-Coupling critical temperature. We also find evidence of a positive spatial correlation between clusters of particles having large displacements in the unstable modes and dynamical heterogeneities.Comment: 7 pages, 3 figures, submitted to Europhys. Let

Not All Patients with Vancomycin-Resistant Enterococci Need To Be Isolated

Background. Vancomycin-resistant enterococci (VRE) have triggered multiple outbreaks. However, VRE of genotype vanC appear not to be associated with outbreaks. The goal of this study was to estimate the risk of bloodstream infections in patients colonized with VRE of genotype vanC who received care from a bone marrow transplant unit for patients with leukemia, where only standard precautions were implemented for VRE of genotype vanC during the last 9 years. Methods. Since 2000, all patients in the bone marrow transplant unit underwent routine VRE rectal screening, data were prospectively entered in a database, and isolates were molecularly characterized. Infection control policy required contact isolation for patients infected with VRE of genotype vanA or vanB but only standard precautions for patients infected with VRE of genotype vanC. Results. From January 2000 to July 2008, 290 isolates of VRE of genotype vanC obtained from 273 different patients were identified, with an incidence of 25-43 isolates/year. Of 290 isolates, 285 (98%) were identified in rectal screening swabs, 5 were from other body sites, and none required specific treatment. During the entire study period, only 1 case of bloodstream infection was detected, reflecting an incidence of 1 (0.4%) of the 273 patients, or <0.2 cases per 1000 patient-days. No outbreaks were recorded. Conclusions. These data provide strong evidence that carriers of VRE of genotype vanC do not require contact isolation, thereby saving resources and potentially improving patient care. The genotype should be routinely determined in areas with a high prevalence of VRE of genotype van

Perforated Peptic Ulcer Repair: Factors Predicting Conversion in Laparoscopy and Postoperative Septic Complications.

The surgical treatment for perforated peptic ulcers can be safely performed laparoscopically. The aim of the study was to define simple predictive factors for conversion and septic complications. This retrospective case-control study analyzed patients treated with either laparoscopic surgery or laparotomy for perforated peptic ulcers. A total of 71 patients were analyzed. Laparoscopically operated patients had a shorter hospital stay (13.7 vs. 15.1 days). In an intention-to-treat analysis, patients with conversion to open surgery (analyzed as subgroup from laparoscopic approach group) showed no prolonged hospital stay (15.3 days) compared to patients with a primary open approach. Complication and mortality rates were not different between the groups. The statistical analysis identified four intraoperative risk factors for conversion: Mannheim peritonitis index (MPI) &gt; 21 (p = 0.02), generalized peritonitis (p = 0.04), adhesions, and perforations located in a region other than the duodenal anterior wall. We found seven predictive factors for septic complications: age &gt;70 (p = 0.02), cardiopulmonary disease (p = 0.04), ASA &gt; 3 (p = 0.002), CRP &gt; 100 (p = 0.005), duration of symptoms &gt;24 h (p = 0.02), MPI &gt; 21(p = 0.008), and generalized peritonitis (p = 0.02). Our data suggest that a primary laparoscopic approach has no disadvantages. Factors necessitating conversions emerged during the procedure inhibiting a preoperative selection. Factors suggesting imminent septic complications can be assessed preoperatively. An assessment of the proposed parameters may help optimize the management of possible septic complications

Electrical current distribution across a metal-insulator-metal structure during bistable switching

Combining scanning electron microscopy (SEM) and electron-beam-induced current (EBIC) imaging with transport measurements, it is shown that the current flowing across a two-terminal oxide-based capacitor-like structure is preferentially confined in areas localized at defects. As the thin-film device switches between two different resistance states, the distribution and intensity of the current paths, appearing as bright spots, change. This implies that switching and memory effects are mainly determined by the conducting properties along such paths. A model based on the storage and release of charge carriers within the insulator seems adequate to explain the observed memory effect.Comment: 8 pages, 7 figures, submitted to J. Appl. Phy