bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spontaneous aberrant right subclavian arterio-oesophageal fistula in a previously healthy child
Authors: Joynt Michael R. , Grifka Ronald G. 
Published: December 2014

AbstractAn aberrant right subclavian artery arising from a left aortic arch is the most frequently described congenital aortic arch anomaly, occurring in 0.5 to 2.3% of the general population. Despite the retro-oesophageal course of the aberrant subclavian artery, an arterio-oesophageal fistula is an uncommon finding, only previously reported as a very rare complication in critically ill patients with oesophageal instrumentation or foreign body ingestion. We describe a unique case of a spontaneous aberrant right subclavian arterio-oesophageal fistula without an inciting event in a 17-month-child.
Spatial scales of bacterial community diversity at cold seeps (Eastern Mediterranean Sea)
Authors: Pop Ristova Petra , Wenzhöfer Frank , Ramette Alban , Felden Janine , Boetius Antje 
Published: December 2014

Abstract
Cold seeps are highly productive, fragmented marine ecosystems that form at the seafloor around hydrocarbon emission pathways. The products of microbial utilization of methane and other hydrocarbons fuel rich chemosynthetic communities at these sites, with much higher respiration rates compared with the surrounding deep-sea floor. Yet little is known as to the richness, composition and spatial scaling of bacterial communities of cold seeps compared with non-seep communities. Here we assessed the bacterial diversity across nine different cold seeps in the Eastern Mediterranean deep-sea and surrounding seafloor areas. Community similarity analyses were carried out based on automated ribosomal intergenic spacer analysis (ARISA) fingerprinting and high-throughput 454 tag sequencing and were combined with in situ and ex situ geochemical analyses across spatial scales of a few tens of meters to hundreds of kilometers. Seep communities were dominated by Deltaproteobacteria, Epsilonproteobacteria and Gammaproteobacteria and shared, on average, 36% of bacterial types (ARISA OTUs (operational taxonomic units)) with communities from nearby non-seep deep-sea sediments. Bacterial communities of seeps were significantly different from those of non-seep sediments. Within cold seep regions on spatial scales of only tens to hundreds of meters, the bacterial communities differed considerably, sharing &lt;50% of types at the ARISA OTU level. Their variations reflected differences in porewater sulfide concentrations from anaerobic degradation of hydrocarbons. This study shows that cold seep ecosystems contribute substantially to the microbial diversity of the deep-sea.
Is there a common water-activity limit for the three domains of life?
Authors: Stevenson Andrew , Cray Jonathan A , Williams Jim P , Santos Ricardo , Sahay Richa , Neuenkirchen Nils , McClure Colin D , Grant Irene R , Houghton Jonathan D R , Quinn John P , Timson David J , Patil Satish V , Singhal Rekha S , Antón Josefa , Dijksterhuis Jan , Hocking Ailsa D , Lievens Bart , Rangel Drauzio E N , Voytek Mary A , Gunde-Cimerman Nina , Oren Aharon , Timmis Kenneth N , McGenity Terry J , Hallsworth John E 
Published: December 2014

Abstract
Archaea and Bacteria constitute a majority of life systems on Earth but have long been considered inferior to Eukarya in terms of solute tolerance. Whereas the most halophilic prokaryotes are known for an ability to multiply at saturated NaCl (water activity (aw) 0.755) some xerophilic fungi can germinate, usually at high-sugar concentrations, at values as low as 0.650–0.605 aw. Here, we present evidence that halophilic prokayotes can grow down to water activities of &lt;0.755 for Halanaerobium lacusrosei (0.748), Halobacterium strain 004.1 (0.728), Halobacterium sp. NRC-1 and Halococcus morrhuae (0.717), Haloquadratum walsbyi (0.709), Halococcus salifodinae (0.693), Halobacterium noricense (0.687), Natrinema pallidum (0.681) and haloarchaeal strains GN-2 and GN-5 (0.635 aw). Furthermore, extrapolation of growth curves (prone to giving conservative estimates) indicated theoretical minima down to 0.611 aw for extreme, obligately halophilic Archaea and Bacteria. These were compared with minima for the most solute-tolerant Bacteria in high-sugar (or other non-saline) media (Mycobacterium spp., Tetragenococcus halophilus, Saccharibacter floricola, Staphylococcus aureus and so on) and eukaryotic microbes in saline (Wallemia spp., Basipetospora halophila, Dunaliella spp. and so on) and high-sugar substrates (for example, Xeromyces bisporus, Zygosaccharomyces rouxii, Aspergillus and Eurotium spp.). We also manipulated the balance of chaotropic and kosmotropic stressors for the extreme, xerophilic fungi Aspergillus penicilloides and X. bisporus and, via this approach, their established water-activity limits for mycelial growth (∼0.65) were reduced to 0.640. Furthermore, extrapolations indicated theoretical limits of 0.632 and 0.636 aw for A. penicilloides and X. bisporus, respectively. Collectively, these findings suggest that there is a common water-activity limit that is determined by physicochemical constraints for the three domains of life.
Evidence for extensive gene flow and Thermotoga subpopulations in subsurface and marine environments
Authors: Nesbø Camilla L , S Swithers Kristen , Dahle Håkon , Haverkamp Thomas H A , Birkeland Nils-Kåre , Sokolova Tatiana , Kublanov Ilya , Zhaxybayeva Olga 
Published: December 2014

Abstract
Oil reservoirs represent a nutrient-rich ecological niche of the deep biosphere. Although most oil reservoirs are occupied by microbial populations, when and how the microbes colonized these environments remains unanswered. To address this question, we compared 11 genomes of Thermotoga maritima-like hyperthermophilic bacteria from two environment types: subsurface oil reservoirs in the North Sea and Japan, and marine sites located in the Kuril Islands, Italy and the Azores. We complemented our genomes with Thermotoga DNA from publicly available subsurface metagenomes from North America and Australia. Our analysis revealed complex non-bifurcating evolutionary history of the isolates’ genomes, suggesting high amounts of gene flow across all sampled locations, a conjecture supported by numerous recombination events. Genomes from the same type of environment tend to be more similar, and have exchanged more genes with each other than with geographically close isolates from different types of environments. Hence, Thermotoga populations of oil reservoirs do not appear isolated, a requirement of the ‘burial and isolation’ hypothesis, under which reservoir bacteria are descendants of the isolated communities buried with sediments that over time became oil reservoirs. Instead, our analysis supports a more complex view, where bacteria from subsurface and marine populations have been continuously migrating into the oil reservoirs and influencing their genetic composition. The Thermotoga spp. in the oil reservoirs in the North Sea and Japan probably entered the reservoirs shortly after they were formed. An Australian oil reservoir, on the other hand, was likely colonized very recently, perhaps during human reservoir development.
Quantum state-controlled directional spontaneous emission of photons into a nanophotonic waveguide
Authors: Mitsch R. , Sayrin C. , Albrecht B. , Schneeweiss P. , Rauschenbeutel A. 
Published: December 2014

AbstractThe spin of light in subwavelength-diameter waveguides can be orthogonal to the propagation direction of the photons because of the strong transverse confinement. This transverse spin changes sign when the direction of propagation is reversed. Using this effect, we demonstrate the directional spontaneous emission of photons by laser-trapped caesium atoms into an optical nanofibre and control their propagation direction by the excited state of the atomic emitters. In particular, we tune the spontaneous emission into the counter-propagating guided modes from symmetric to strongly asymmetric, where more than "Equation missing"% of the optical power is launched into one or the other direction. We expect our results to have important implications for research in quantum nanophotonics and for implementations of integrated optical signal processing in the quantum regime.
p38α (MAPK14) critically regulates the immunological response and the production of specific cytokines and chemokines in astrocytes
Authors: Lo U. , Selvaraj V. , Plane J. M. , Chechneva O. V. , Otsu K. , Deng W. 
Published: December 2014

AbstractIn CNS lesions, “reactive astrocytes” form a prominent cellular response. However, the nature of this astrocyte immune activity is not well understood. In order to study astrocytic immune responses to inflammation and injury, we generated mice with conditional deletion of p38α (MAPK14) in GFAP+ astrocytes. We studied the role of p38α signaling in astrocyte immune activation both in vitro and in vivo and simultaneously examined the effects of astrocyte activation in CNS inflammation. Our results showed that specific subsets of cytokines (TNFα, IL-6) and chemokines (CCL2, CCL4, CXCL1, CXCL2, CXCL10) are critically regulated by p38α signaling in astrocytes. In an in vivo CNS inflammation model of intracerebral injection of LPS, we observed markedly attenuated astrogliosis in conditional GFAPcre p38α−/− mice. However, GFAPcre p38α−/− mice showed marked upregulation of CCL2, CCL3, CCL4, CXCL2, CXCL10, TNFα and IL-1β compared to p38αfl/fl cohorts, suggesting that in vivo responses to LPS after GFAPcre p38α deletion are complex and involve interactions between multiple cell types. This finding was supported by a prominent increase in macrophage/microglia and neutrophil recruitment in GFAPcre p38α−/− mice compared to p38αfl/fl controls. Together, these studies provide important insights into the critical role of p38α signaling in astrocyte immune activation.
Cell capacitor sizing in multilevel converters: cases of the modular multilevel converter and alternate arm converter
Authors: Merlin Michaël M. C. , Green Tim C. 
Published: December 2014

Multilevel converters, such as the modular multilevel converter (MMC) or the alternate arm converter (AAC), rely on charged capacitors in their cells to generate their AC voltage waveform. Since the cell capacitors are physically large and occupy approximately half the cell volume, their capacitance must be kept minimal while limiting the voltage fluctuation caused by the current passing periodically through these capacitors. This study proposes a mathematical model which estimates the energy deviation for the stacks of both the MMC and the AAC during steady‐state operation under any power factor and for AC voltage magnitude fluctuation of up to ±10%. The analysis is then used to calculate the minimum size for the cell capacitors in order to keep their voltage fluctuation within set boundaries for both topologies. The results show that the MMC requires 39 kJ/MVA of capacitive energy storage under sinusoidal modulation but this reduces with triplen injection modulation. The AAC has a lower requirement for storage in its cells of 11 kJ/MVA but the AAC has a six‐pulse DC current ripple which requires a filter estimated to have a further 33% capacitive storage.
Improvement on voltage gain for KY converter
Authors: Hwu Kuo‐Ing , Jiang Wen‐Zhuang 
Published: December 2014

A novel step‐up converter, which combines a KY converter, which is named after the first capitals of two authors’ names: Hwu and Yau, a traditional synchronously rectified (SR) boost converter, and a coupled inductor with turns ratio, is presented in this study. In this converter, these two combined converters use the same switches. Also, since the proposed converter possesses an output inductor, the output current is non‐pulsating because of synchronous rectification. Moreover, the corresponding voltage gain is greater than those of the traditional boost converter and the existing converters with output inductors. Furthermore, part of the leakage inductance energy can be recycled to the output capacitor of the SR boost converter. Therefore such a converter is very suitable for low‐ripple applications. In addition, this converter is driven using only one half‐bridge gate driver. Finally, mathematical deductions and an experimental setup with 12 V input voltage, 72 V output voltage and 60 W output power are used to verify the effectiveness of the proposed converter.
Computer-Aided Surgery Does Not Increase the Accuracy of Dorsal Pedicle Screw Placement in the Thoracic and Lumbar Spine: A Retrospective Analysis of 2,003 Pedicle Screws in a Level I Trauma Center
Authors: Kraus Michael , Weiskopf Julia , Dreyhaupt Jens , Krischak Gert , Gebhard Florian 
Published: December 2014

Study Design A retrospective analysis of a prospective database. Objective Meta-analyses suggest that computer-assisted systems can increase the accuracy of pedicle screw placement for dorsal spinal fusion procedures. The results of further meta-analyses report that in the thoracic spine, both the methods have comparable placement accuracy. These studies are limited due to an abundance of screw classification systems. The aim of this study was to assess the placement accuracy and potentially influencing factors of three-dimensionally navigated versus conventionally inserted pedicle screws. Methods This was a retrospective analysis of a prospective database at a level I trauma center of pedicle screw placement (computer-navigated versus traditionally placed) for dorsal spinal stabilizations. The cases spanned a 5.5-year study period (January 1, 2005, to June 30, 2010). The perforations of the pedicle were differentiated in three grades based on the postoperative computed tomography. Results The overall placement accuracy was 86% in the conventional group versus 79% in the computer-navigated group (grade 0). The computer-navigated procedures were superior in the lumbar spine and the conventional procedures were superior in the thoracic spine, but both failed to be of statistical significance. The level of experience of the performing surgeon and the patient's body mass index did not influence the placement accuracy. The only significant influence was the spinal segment: the higher the spinal level where the fusion was performed, the more likely the screw was displaced. Conclusions The computer-navigated and conventional methods are both safe procedures to place transpedicular screws at the traumatized thoracic and lumbar spine. At the moment, three-dimensionally based navigation does not significantly increase the placement accuracy.
Collaborative communication networks: an application in Indonesia.
Authors: Pennington-Gray L. , Cahyanto I. , Schroeder A. , Kesper A. 
Published: December 2014

Abstract

This chapter argues that because tourism comprises multiple stakeholders, it is critical that crisis management for the tourism industry is integrated with other organizations, government departments, emergency personnel, media and other stakeholders. After providing a discussion of potential collaboration theories, it provides a working example of collaborative communication networks that have been created in Indonesia as a response to the need to address communication issues during and after a disaster. There are two tangible programmes in Indonesia that involve a collaborative communication process in tourism. The first programme is the Bali Hotels Security and Safety Radio (BHSSR), whereby the hotel sector has access to very high frequency radios used by the Bali police force in order to receive information surrounding crises. The second programme is the Bali Hotels Association Multi-Purpose Tsunami Early Warning and Emergency Short Message Service (SMS) System.
Influence of the Global Financial Crisis (GFC) on the Chinese outbound travel market: a case study of the Shanghai regional market.
Authors: Ma E. , Zhang Yan Zhang Yan , Qu HaiLin Qu HaiLin 
Published: December 2014

Abstract

By learning from the influence of the GFC on the Chinese outbound travel market using a case study of the Shanghai regional market, this chapter notes that tourists from Shanghai have been surprisingly resilient to the GFC. The expenditure intention of potential outbound tourists from Shanghai indicated that the majority of tourists would not reduce their travel expenditure during the GFC. In fact, quite a large percentage of them would increase their spending, particularly in leisure, recreation and shopping. The implication is that, even during the GFC, Shanghai residents' outbound travel need is still strong and robust. Shanghai tourists' need for and motivation to travel outbound are not easily affected by the GFC, and this is in contrast to outbound tourists from the USA or those from some European countries influenced by the GFC.
The development of new tourism networks to respond to and recover from the 2011 Christchurch earthquake.
Authors: Becken S. , Scott N. , Ritchie B. W. 
Published: December 2014

Abstract

After examining the new tourism networks that developed as a response to and during recovery from the 2011 Christchurch earthquake, this chapter suggests that tourism businesses have to work collaboratively with different organizations to recover and ensure business continuity. Using a business network approach, the chapter identifies the most salient issues that may affect turnaround and the differences between networks before and after the earthquake.
Ecotourism as a sustainable recovery tool after an earthquake.
Authors: Wang ChinChin Wang ChinChin , Cater C. 
Published: December 2014

Abstract

This chapter investigates the potential for tourism development to contribute to recovery strategies following earthquakes. It examines changes to livelihood assets in a rural community setting in Taiwan that had suffered a major earthquake in 1999 and subsequently sought to develop an ecotourism product. Using the community-based model, the chapter presents a dynamic representation in the form of a four-circle structure to explain all the relationships that have been developed following a major earthquake. These four systems can exist in two states between different forms of capital: balanced and dynamic. When an external change such as a natural disaster presents a key trigger, this can bring positive and negative changes to and between the financial, physical, social, cultural and natural capital. The focus on capital and the interrelationships between different types of capital are important as they indicate how changes to one form of capital can disrupt the other types of capital, which may influence sustainable livelihoods.
The devastation of Darwin: representing the recovery and reconstruction of Australia after Cyclone Tracy.
Authors: White L. , Frew E. 
Published: December 2014

Abstract

This chapter suggests that crisis experiences should be documented so that tourism stakeholders can learn from, and be educated by, previous crises. By examining the permanent exhibition of Cyclone Tracy at the Museum and Art Galley of the Northern Territory in Darwin, the chapter explores the ways in which a tragic event in Australia has been commemorated and interpreted within the context of tourism and national identity. The chapter explains the importance of effectively interpreting a significant tragic event such as Cyclone Tracy. More importantly, the existence of this permanent exhibition allows Australians to remember the event in perpetuity and to place it in context with the development of their nation.
3D morphology of a random field from its 2D cross-section
Authors: Makarenko Irina , Fletcher Andrew , Shukurov Anvar 
Published: December 2014

Abstract
The two aspect ratios of randomly oriented triaxial ellipsoids (representing isosurfaces of an isotropic 3D random field) can be determined from a single 2D cross-section of their sample using the probability density function (PDF) of the filamentarityF of individual structures seen in cross-section (F = 0 for a circle and F = 1 for a line). The PDF of F has a robust form with a sharp maximum and truncation at larger F, and the most probable and maximum values of F are uniquely and simply related to the two aspect ratios of the triaxial ellipsoids. The parameters of triaxial ellipsoids of randomly distributed sizes can still be recovered from the PDF of F. This method is applicable to many shape-recognition problems, here illustrated by the neutral hydrogen density in the turbulent interstellar medium of the Milky Way. The gas distribution is shown to be filamentary with axis ratios of about 1:2:20.
The role of the inner disk in mass accretion to the star in the early phase of star formation
Authors: Ohtani Takuya , Kimura Shigeo S. , Tsuribe Toru , Vorobyov Eduard I. 
Published: December 2014

Abstract
A physical mechanism that drives FU Orionis-type outbursts is reconsidered. We study the effect of the inner part of a circumstellar disk covering a region from near the central star to a radius of approximately 5 au (hereafter, the inner disk). Using the fluctuating mass accretion rate onto the inner disk $\dot{M}\,_{\rm out}$, we consider the viscous evolution of the inner disk and the time variability of the mass accretion rate onto the central star $\dot{M}\,_{\rm in}$ by means of numerical calculation of an unsteady viscous accretion disk in a one-dimensional axisymmetric model. First, we calculate the evolution of the inner disk assuming an oscillating $\dot{M}\,_{\rm out}$. It is shown that the time variability of $\dot{M}\,_{\rm in}$ does not coincide with $\dot{M}\,_{\rm out}$ due to viscous diffusion. Second, we investigate the properties of spontaneous outbursts with temporally constant $\dot{M}\,_{\rm out}$. Outbursts occur only in a limited range of mass accretion rates onto the inner disk of $10^{-10}&lt;\dot{M}\,_{\rm out}&lt; 3\times 10^{-6}{\,M}_{\odot }\:$yr−1 due to the gravo-magneto limit cycle (GML). Finally, we discuss the case with a combination of episodic $\dot{M}\,_{\rm out}$ and accretion outbursts caused by the GML in the inner disk. The GML can drive accretion outbursts onto the star even for the case of fluctuating $\dot{M}\,_{\rm out}$, although fluctuations of $\dot{M}\,$ decay while transmitting the inner disk inwards. We have newly identified two modes of outburst, one spontaneous and one stimulated. In the stimulated mode of outburst, $\dot{M}\,_{\rm out}$ does appear directly in $\dot{M}\,_{\rm in}$ (the latter defining the stellar accretion luminosity). In the spontaneous mode of outburst, $\dot{M}\,_{\rm out}$ appears as the interval between outbursts.