Deformation of a renormalization-group equation applied to infinite-order phase transitions

By adding a linear term to a renormalization-group equation in a system exhibiting infinite-order phase transitions, asymptotic behavior of running coupling constants is derived in an algebraic manner. A benefit of this method is presented explicitly using several examples.Comment: 6 pages, 5 figures, revtex4, typo corrected, references adde

Positivity of hexagon perturbation theory

The hexagon-form-factor program was proposed as a way to compute three- and higher-point correlation functions in $\mathcal{N}=4$ super-symmetric Yang-Mills theory and in the dual AdS$_5\times$S$^5$ superstring theory, by exploiting the integrability of the theory in the 't Hooft limit. This approach is reminiscent of the asymptotic Bethe ansatz in that it applies to a large-volume expansion. Finite-volume corrections can be incorporated through L\"uscher-like formulae, though the systematics of this expansion is largely unexplored so far. Strikingly, finite-volume corrections may feature negative powers of the 't Hooft coupling $g$ in the small-$g$ expansion, potentially leading to a breakdown of the formalism. In this work we show that the finite-volume perturbation theory for the hexagon is positive and thereby compatible with the weak-coupling expansion for arbitrary $n$-point functions.Comment: v2: misprints corrected, further details on physical magnons adde

Peritoneal drainage for newborn intestinal perforation: primary treatment or unnecessary delay?

Background Peritoneal drainage (PD) was introduced 30 years ago as a temporizing treatment for extremely ill newborns with intestinal perforation (IP). Subsequent reports have shown it to be helpful as a definitive treatment, whereas others have labeled it as an unnecessary delay before laparotomy.Methods This is a retrospective analysis of all newborns (2004–2009) with presumed IP treated with PD irrespective of gestational age or weight. Drainage was achieved with a single Penrose drain placed between incisions in each lower quadrant. This was followed by extensive irrigation. Laparotomy was performed if needed for progressive sepsis, intestinal stricture, or persistent leak. Parameters analyzed included gestational age and weight, time before IP, findings at drain placement, and need for subsequent operations.Results Drains were placed in 24 consecutive newborns with IP. The median gestational age was 29 weeks and weight was 755 g. IP was confirmed in nine (38%) by free air on radiograph. In 15 newborns, PD was performed for progressive sepsis and succus was identified in 11 (73%). The overall mortality rate was 33% (25% in newborns <1500 g, 75% in those >1500 g). No parameters were statistically significant in predicting mortality. PD served as a definitive treatment without the need for further laparotomy in 50% of survivors.Conclusion PD with extensive irrigation for newborns with IP has an acceptable mortality rate. It is not a delay tactic but serves as a definitive treatment for 50% of survivors. Children weighing more than 1500 g and those without succus at the time of drain placement should, however, receive laparotomy as the primary treatment.Keywords: intestinal perforation in newborn, necrotizing enterocolitis, primary peritoneal drainag

Spin-polarized currents in exchange spring systems

We present a computational study of the magnetization dynamics of a trilayer exchange spring system in the form of a cylindrical nanopillar in the presence of an electric current. A three-dimensional micromagnetic model is used, where the interaction between the current and the local magnetization is taken into account following a recent model by Zhang and Li [Phys. Rev. Lett. 93, 127204 (2004)] We obtain a stationary rotation of the magnetization of the system around its axis, accompanied by a compression of the artificial domain wall in the direction of the electron flow

Phylogenomic study of Burkholderia glathei-like organisms, proposal of 13 novel Burkholderia species and emended descriptions of Burkholderia sordidicola, Burkholderia zhejiangensis, and Burkholderia grimmiae

Partial gyrB gene sequence analysis of 17 isolates from human and environmental sources revealed 13 clusters of strains and identified them as Burkholderia glathei Glade (BGC) bacteria. The taxonomic status of these clusters was examined by whole-genome sequence analysis, determination of the G+C content, whole-cell fatty acid analysis and biochemical characterization. The whole-genome sequence-based phylogeny was assessed using the Genome Blast Distance Phylogeny (GBDP) method and an extended multilocus sequence analysis (MLSA) approach. The results demonstrated that these 17 BGC isolates represented 13 novel Burkholderia species that could be distinguished by both genotypic and phenotypic characteristics. BGC strains exhibited a broad metabolic versatility and developed beneficial, symbiotic, and pathogenic interactions with different hosts. Our data also confirmed that there is no phylogenetic subdivision in the genus Burkholderia that distinguishes beneficial from pathogenic strains. We therefore propose to formally classify the 13 novel BGC Burkholderia species as Burkholderia arvi sp. nov. (type strain LMG 29317(T) = CCUG 68412(T)), Burkholderia hypogeia sp. nov. (type strain LMG 29322(T) = CCUG 68407(T)), Burkholderia ptereochthonis sp. nov. (type strain LMG 29326(T) = CCUG 68403(T)), Burkholderia glebae sp. nov. (type strain LMG 29325(T) = CCUG 68404(T)), Burkholderia pedi sp. nov. (type strain LMG 29323(T) = CCUG 68406(T)), Burkholderia arationis sp. nov. (type strain LMG 29324(T) = CCUG 68405(T)), Burkholderia fortuita sp. nov. (type strain LMG 29320(T) = CCUG 68409(T)), Burkholderia temeraria sp. nov. (type strain LMG 29319(T) = CCUG 68410(T)), Burkholderia calidae sp. nov. (type strain LMG 29321(T) = CCUG 68408(T)), Burkholderia concitans sp. nov. (type strain LMG 29315(T) = CCUG 68414(T)), Burkholderia turbans sp. nov. (type strain LMG 29316(T) = CCUG 68413(T)), Burkholderia catudaia sp. nov. (type strain LMG 29318(T) = CCUG 68411(T)) and Burkholderia peredens sp. nov. (type strain LMG 29314(T) = CCUG 68415(T)). Furthermore, we present emended descriptions of the species Burkholderia sordidicola, Burkholderia zhejlangensis and Burkholderia grimmiae. The GenBank/EMBUDDBJ accession numbers for the 16S rRNA and gyrB gene sequences determined in this study are LT158612-LT158624 and LT158625-LT1158641, respectively

Deoxynivalenol and Zearalenone natural occurrence in swine feedstruffs and histopathological analysis

Deoxynivalenol (DON) and Zearalenone (ZEA) are the most frequent and toxicologically important Fusarium mycotoxins detected in cereal grains and feedstuffs, causing toxic effects that impair the performance of farm animals, with pigs being the most susceptible species. The objectives of this study were to evaluate the occurrence of DON and ZEA in feed cereal grains and compound feed destined to swine consumption, to perform a histopathological study using liver samples collected from gilts and sows fed with these compound feeds. Twelve ingredients (unprocessed maize, barley, wheat, bran, rapeseed, soybean) and twenty-six samples of swine compound feed were analyzed. The histopathological study was performed using samples from slaughtered pigs that had been fed the analyzed compound feed for at least two weeks. Results showed that 71.1% of the samples were positive for ZEA and 78.9% for DON. Histologically, diffuse degenerative changes compatible with hepatosis were observed.Desoxinivalenol (DON) e Zearalenona (ZEA) são as micotoxinas de Fusarium mais frequentes e toxicologicamente importantes detetadas em cereais e alimentos para animais, causando efeitos tóxicos que prejudicam o desempenho de animais de produção, sendo os suínos a espécie mais suscetível. Este estudo teve como objetivo avaliar a ocorrência de DON e ZEA em grãos de cereais e alimentos compostos destinados ao consumo de suínos, bem como realizar um estudo histopatológico com a utilização de amostras de fígado recolhidas de marrãs e porcas alimentadas com estes alimentos compostos. Foram analisados doze ingredientes (milho não processado, cevada, trigo, farelo, colza, soja) e vinte e seis amostras de alimento composto para suínos. O estudo histopatológico foi realizado utilizando amostras de suínos abatidos que haviam sido alimentados com os alimentos compostos analisados durante pelo menos duas semanas. Verificou-se que 71,1% das amostras foram positivas para a ZEA e 78,9% para a DON. Histologicamente, foram observadas alterações degenerativas difusas compatíveis com hepatose

Having a direct look:analysis of DNA damage and repair mechanisms by next generation sequencing

AbstractGenetic information is under constant attack from endogenous and exogenous sources, and the use of model organisms has provided important frameworks to understand how genome stability is maintained and how various DNA lesions are repaired. The advance of high throughput next generation sequencing (NGS) provides new inroads for investigating mechanisms needed for genome maintenance. These emerging studies, which aim to link genetic toxicology and mechanistic analyses of DNA repair processes in vivo, rely on defining mutational signatures caused by faulty replication, endogenous DNA damaging metabolites, or exogenously applied genotoxins; the analysis of their nature, their frequency and distribution. In contrast to classical studies, where DNA repair deficiency is assessed by reduced cellular survival, the localization of DNA repair factors and their interdependence as well as limited analysis of single locus reporter assays, NGS based approaches reveal the direct, quantal imprint of mutagenesis genome-wide, at the DNA sequence level. As we will show, such investigations require the analysis of DNA derived from single genotoxin treated cells, or DNA from cell populations regularly passaged through single cell bottlenecks when naturally occurring mutation accumulation is investigated. We will argue that the life cycle of the nematode Caenorhabditis elegans, its genetic malleability combined with whole genome sequencing provides an exciting model system to conduct such analysis

Weak localization and spin splitting in inversion layers on p-type InAs

We report on the magnetoconductivity of quasi two-dimensional electron systems in inversion layers on p-type InAs single crystals. In low magnetic fields pronounced features of weak localization and antilocalization are observed. They are almost perfectly described by the theory of Iordanskii, Lyanda-Geller and Pikus. This allows us to determine the spin splitting and the Rashba parameter of the ground electric subband as a function of the electron density.Comment: Accepted for publication in Phys. Rev. B, 4 page

Semiclassical analysis of the lowest-order multipole deformations of simple metal clusters

We use a perturbative semiclassical trace formula to calculate the three lowest-order multipole (quadrupole \eps_2, octupole \eps_3, and hexadecapole \eps_4) deformations of simple metal clusters with $90 \le N \le 550$ atoms in their ground states. The self-consistent mean field of the valence electrons is modeled by an axially deformed cavity and the oscillating part of the total energy is calculated semiclassically using the shortest periodic orbits. The average energy is obtained from a liquid-drop model adjusted to the empirical bulk and surface properties of the sodium metal. We obtain good qualitative agreement with the results of quantum-mechanical calculations using Strutinsky's shell-correction method.Comment: LaTeX file (v2) 6 figures, to be published in Phys. Lett.