bluuebunny/crossref_metadata_2025 huggingface dataset:
First Report of Mature Citrus Trees Being Affected by Fusarium Wilt in Tunisia
Authors: Hannachi I. , Rezgui S. , Cherif M.
Published: September 2013

Citrus is an important crop in Tunisia and over 98% of trees of all varieties are grafted on sour orange rootstock. Since September 2010, unusual wilt symptoms have been observed in Takilsa, Bni-Khaled, and Manzel Bouzalfa fields that eventually caused tree death. The disease was observed on 10- to 25-year-old trees of sweet orange (Citrus sinensis) ‘Washington Navel’ and on ‘Clementine’ tangerines (C. tangerina) ‘Cassar,’ ‘Hernandina,’ and ‘MA3,’ all grafted on sour orange (C. aurantum) ‘Bigarade Gou Tou.’ The most conspicuous symptoms were wilting of sections of the canopy, chlorosis and epinasty of young leaves, and discoloration of vascular tissue. No root rot was observed. The problem was widespread with a disease incidence of 45 to 67%. Similar symptoms were described by Timmer et al. (2) on Mexican lime (C. aurantiifolia) nursery plants and some other species of citrus. Three representative isolates of Fusarium oxysporum Schlechtend.:Fr. from crown were single-spored and identified by the production of characteristic, three- to five-celled, sickle-shaped macroconidia with foot-shaped basal cells, ellipsoid microconidia borne in false heads on short monophialides, and chlamydospores in culture (1). The internal transcribed spacer (ITS) region of rDNA and the elongation factor (TEF 1-α) were amplified with primers ITS1/ITS4 and (TEF1/TEF2), respectively. GenBank accessions of ITS region are KC282838, KC282839, and KC282840, for TEF 1-α region are KF531633, KF537336, and KF537337, showed 99% homology with isolates of F. oxysporum in Fusarium-ID data. Pathogenicity tests were conducted on 7-month-old seedlings of sour orange using 10 plants for each of the three isolates. Prior to inoculation, roots were scraping with a sterile scalpel and plants were dipped in a conidial suspension of F. oxysporum (106 conidia ml–1) for 10 min. Each seedling was planted in a separate pot containing 0.7 liter of sterile soil. Non-inoculated plants with scraped roots dipped in sterile distilled water served as controls. Plants were irrigated and placed in a greenhouse at 24 ± 2°C and 12-h photoperiod. One month after inoculation, leaf chlorosis was observed and 2 months later, 90% of inoculated plants presented a severe wilt. Symptoms on infected plants were similar to those observed in the field. F. oxysporum was successfully re-isolated from the stems, thereby completing Koch's postulates. Genomic DNA was isolated from the re-isolations and PCR amplification of the ITS region was performed with the same primers. There was 100% nucleotide identity with sequences of the original isolates. To our knowledge, this is the first report of fusarium wilt of citrus trees in Tunisia. The pathogen may represent a new form species because previously, the disease was only reported from lime and lemon.

References: (1) J. F. Leslie and B. A. Summerell. Page 256 in: The Fusarium Laboratory Manual. Blackwell Publishing Professional, Hoboken, NJ, 2006. (2) L. W. Timmer et al. Phytopathology 72:698, 1982.
Prenatal exposure to testosterone impairs oxidative damage repair efficiency in the domestic chicken (
Gallus gallus
)
Authors: Treidel L. A. , Whitley B. N. , Benowitz-Fredericks Z M. , Haussmann M. F.
Published: September 2013

Elevated levels of maternal androgens in avian eggs affect numerous traits, including oxidative stress. However, current studies disagree as to whether prenatal androgen exposure enhances or ameliorates oxidative stress. Here, we tested how prenatal testosterone exposure affects oxidative stress in female domestic chickens (
Gallus gallus
) during the known oxidative challenge of an acute stressor. Prior to incubation, eggs were either injected with an oil vehicle or 5 ng testosterone. At either 17 or 18 days post-hatch, several oxidative stress markers were assessed from blood taken before and after a 20 min acute stressor, as well as following a 25 min recovery from the stressor. We found that, regardless of yolk treatment, during both stress and recovery all individuals were in a state of oxidative stress, with elevated levels of oxidative damage markers accompanied by a reduced total antioxidant capacity. In addition, testosterone-exposed individuals exhibited poorer DNA damage repair efficiencies in comparison with control individuals. Our work suggests that while yolk androgens do not alter oxidative stress directly, they may impair mechanisms of oxidative damage repair.
Why is combinatorial communication rare in the natural world, and why is language an exception to this trend?
Authors: Scott-Phillips Thomas C. , Blythe Richard A.
Published: September 2013

In a combinatorial communication system, some signals consist of the combinations of other signals. Such systems are more efficient than equivalent, non-combinatorial systems, yet despite this they are rare in nature. Why? Previous explanations have focused on the adaptive limits of combinatorial communication, or on its purported cognitive difficulties, but neither of these explains the full distribution of combinatorial communication in the natural world. Here, we present a nonlinear dynamical model of the emergence of combinatorial communication that, unlike previous models, considers how initially non-communicative behaviour evolves to take on a communicative function. We derive three basic principles about the emergence of combinatorial communication. We hence show that the interdependence of signals and responses places significant constraints on the historical pathways by which combinatorial signals might emerge, to the extent that anything other than the most simple form of combinatorial communication is extremely unlikely. We also argue that these constraints can be bypassed if individuals have the socio-cognitive capacity to engage in ostensive communication. Humans, but probably no other species, have this ability. This may explain why language, which is massively combinatorial, is such an extreme exception to nature's general trend for non-combinatorial communication.
Engineering anisotropy to amplify a long-wavelength field without a limit
Authors: Liu L. P. , Onofrei D.
Published: September 2013

We present a simple design of circular or spherical shells capable of amplifying a long-wavelength or static field. This design makes use of only two isotropic materials and is optimally restricted to the prescribed geometric and materials constraint. Furthermore, it is shown that the amplification factor of the structure can be made arbitrarily large as the ratio of the radius of the inner sphere to that of the outer sphere decreases to zero. It is anticipated that the presented design will be useful for high-gain antennae for telecommunications, magnets generating strong, local uniform fields and thermoelectric devices harvesting thermal energy, among other applications.
Adaptive radiation of chemosymbiotic deep-sea mussels
Authors: Lorion Julien , Kiel Steffen , Faure Baptiste , Kawato Masaru , Ho Simon Y. W. , Marshall Bruce , Tsuchida Shinji , Miyazaki Jun-Ichi , Fujiwara Yoshihiro
Published: September 2013

Adaptive radiations present fascinating opportunities for studying the evolutionary process. Most cases come from isolated lakes or islands, where unoccupied ecological space is filled through novel adaptations. Here, we describe an unusual example of an adaptive radiation: symbiotic mussels that colonized island-like chemosynthetic environments such as hydrothermal vents, cold seeps and sunken organic substrates on the vast deep-sea floor. Our time-calibrated molecular phylogeny suggests that the group originated and acquired sulfur-oxidizing symbionts in the Late Cretaceous, possibly while inhabiting organic substrates and long before its major radiation in the Middle Eocene to Early Oligocene. The first appearance of intracellular and methanotrophic symbionts was detected only after this major radiation. Thus, contrary to expectations, the major radiation may have not been triggered by the evolution of novel types of symbioses. We hypothesize that environmental factors, such as increased habitat availability and/or increased dispersal capabilities, sparked the radiation. Intracellular and methanotrophic symbionts were acquired in several independent lineages and marked the onset of a second wave of diversification at vents and seeps. Changes in habitat type resulted in adaptive trends in shell lengths (related to the availability of space and energy, and physiological trade-offs) and in the successive colonization of greater water depths.
A parasitic selfish gene that affects host promiscuity
Authors: Giraldo-Perez Paulina , Goddard Matthew R.
Published: September 2013

Selfish genes demonstrate transmission bias and invade sexual populations despite conferring no benefit to their hosts. While the molecular genetics and evolutionary dynamics of selfish genes are reasonably well characterized, their effects on hosts are not. Homing endonuclease genes (HEGs) are one well-studied family of selfish genes that are assumed to be benign. However, we show that carrying HEGs is costly for
Saccharomyces cerevisiae
, demonstrating that these genetic elements are not necessarily benign but maybe parasitic. We estimate a selective load of approximately 1–2% in ‘natural’ niches. The second aspect we examine is the ability of HEGs to affect hosts' sexual behaviour. As all selfish genes critically rely on sex for spread, then any selfish gene correlated with increased host sexuality will enjoy a transmission advantage. While classic parasites are known to manipulate host behaviour, we are not aware of any evidence showing a selfish gene is capable of affecting host promiscuity. The data presented here show a selfish element may increase the propensity of its eukaryote host to undergo sex and along with increased rates of non-Mendelian inheritance, this may counterbalance mitotic selective load and promote spread. Demonstration that selfish genes are correlated with increased promiscuity in eukaryotes connects with ideas suggesting that selfish genes promoted the evolution of sex initially.
Pontibacter indicus sp. nov., isolated from hexachlorocyclohexane-contaminated soil
Authors: Singh Amit Kumar , Garg Nidhi , Lata Pushp , Kumar Roshan , Negi Vivek , Vikram Surendra , Lal Rup
Published: September 2013

An orange-pigmented bacterial strain, designated LP100T, was isolated from hexachlorocyclohexane-contaminated soil (Lucknow, India). A neighbour-joining tree based on 16S rRNA gene sequences showed that strain LP100T occupied a distinct phylogenetic position in the

Pontibacter

species cluster, showing highest similarity with

Pontibacter lucknowensis

DM9T (97.4 %). Levels of similarity to strains of other

Pontibacter

species ranged between 94.0 and 96.8 %. Strain LP100T contained MK-7 as the predominant menaquinone and sym-homospermidine was the major polyamine in the cell. The major cellular fatty acids of strain LP100T were anteiso-C17 : 0 A, iso-C15 : 0 and iso-C18 : 1 H. The polar lipid profile of strain LP100T showed the presence of phosphatidylethanolamine, an unidentified aminophospholipid, three unknown aminolipids and two unknown polar lipids. The G+C content of strain LP100T was 58.2 mol%. The results of DNA–DNA hybridization, biochemical and physiological tests clearly distinguish the novel strain from closely related species of the genus

Pontibacter

. Therefore, strain LP100T represents a novel species of the genus

Pontibacter

for which the name Pontibacter indicus is proposed. The type strain is LP100T ( = CCM8435T = MCC2027T).
Nakazawaea siamensis f.a., sp. nov., a yeast species isolated from phylloplane
Authors: Kaewwichian Rungluk , Limtong Savitree
Published: September 2013

Strain DMKU-RK467T, representing a novel yeast species, was isolated from the external surface of sugar cane leaves collected in Thailand. On the basis of morphological, biochemical, physiological and chemotaxonomic characteristics, and sequence analysis of the D1/D2 region of the LSU rRNA gene and the internal transcribed spacer (ITS) region, strain DMKU-RK467T was assigned to a novel species of the genus Nakazawaea. The novel species was related most closely to the type strain of Candida wickerhamii but they differed by 1.9 % nucleotide substitutions in the D1/D2 region of the LSU rRNA gene and by 5.2 % nucleotide substitutions in the ITS region. The name Nakazawaea siamensis f.a., sp. nov. is proposed (type strain DMKU-RK467T = BCC 50734T = NBRC 108903T = CBS 12569T).
The impact of sleep loss on hippocampal function
Authors: Prince Toni-Moi , Abel Ted
Published: September 2013

Hippocampal cellular and molecular processes critical for memory consolidation are affected by the amount and quality of sleep attained. Questions remain with regard to how sleep enhances memory, what parameters of sleep after learning are optimal for memory consolidation, and what underlying hippocampal molecular players are targeted by sleep deprivation to impair memory consolidation and plasticity. In this review, we address these topics with a focus on the detrimental effects of post-learning sleep deprivation on memory consolidation. Obtaining adequate sleep is challenging in a society that values “work around the clock.” Therefore, the development of interventions to combat the negative cognitive effects of sleep deprivation is key. However, there are a limited number of therapeutics that are able to enhance cognition in the face of insufficient sleep. The identification of molecular pathways implicated in the deleterious effects of sleep deprivation on memory could potentially yield new targets for the development of more effective drugs.
A Membrane-Bound NAC Transcription Factor, ANAC017, Mediates Mitochondrial Retrograde Signaling in Arabidopsis
Authors: Ng Sophia , Ivanova Aneta , Duncan Owen , Law Simon R. , Van Aken Olivier , De Clercq Inge , Wang Yan , Carrie Chris , Xu Lin , Kmiec Beata , Walker Hayden , Van Breusegem Frank , Whelan James , Giraud Estelle
Published: September 2013

Plants require daily coordinated regulation of energy metabolism for optimal growth and survival and therefore need to integrate cellular responses with both mitochondrial and plastid retrograde signaling. Using a forward genetic screen to characterize regulators of alternative oxidase1a (rao) mutants, we identified RAO2/Arabidopsis NAC domain-containing protein17 (ANAC017) as a direct positive regulator of AOX1a. RAO2/ANAC017 is targeted to connections and junctions in the endoplasmic reticulum (ER) and F-actin via a C-terminal transmembrane (TM) domain. A consensus rhomboid protease cleavage site is present in ANAC017 just prior to the predicted TM domain. Furthermore, addition of the rhomboid protease inhibitor N-p-Tosyl-l-Phe chloromethyl abolishes the induction of AOX1a upon antimycin A treatment. Simultaneous fluorescent tagging of ANAC017 with N-terminal red fluorescent protein (RFP) and C-terminal green fluorescent protein (GFP) revealed that the N-terminal RFP domain migrated into the nucleus, while the C-terminal GFP tag remained in the ER. Genome-wide analysis of the transcriptional network regulated by RAO2/ANAC017 under stress treatment revealed that RAO2/ANAC017 function was necessary for >85% of the changes observed as a primary response to cytosolic hydrogen peroxide (H2O2), but only ∼33% of transcriptional changes observed in response to antimycin A treatment. Plants with mutated rao2/anac017 were more stress sensitive, whereas a gain-of-function mutation resulted in plants that had lower cellular levels of H2O2 under untreated conditions.
Predictive Model of Avian Electrocution Risk on Overhead Power Lines
Authors: DWYER J. F. , HARNESS R. E. , DONOHUE K.
Published: September 2013

Electrocution on overhead power structures negatively affects avian populations in diverse ecosystems worldwide, contributes to the endangerment of raptor populations in Europe and Africa, and is a major driver of legal action against electric utilities in North America. We investigated factors associated with avian electrocutions so poles that are likely to electrocute a bird can be identified and retrofitted prior to causing avian mortality. We used historical data from southern California to identify patterns of avian electrocution by voltage, month, and year to identify species most often killed by electrocution in our study area and to develop a predictive model that compared poles where an avian electrocution was known to have occurred (electrocution poles) with poles where no known electrocution occurred (comparison poles). We chose variables that could be quantified by personnel with little training in ornithology or electric systems. Electrocutions were more common at distribution voltages (≤33 kV) and during breeding seasons and were more commonly reported after a retrofitting program began. Red‐tailed Hawks (Buteo jamaicensis) (n = 265) and American Crows (Corvus brachyrhynchos) (n = 258) were the most commonly electrocuted species. In the predictive model, 4 of 14 candidate variables were required to distinguish electrocution poles from comparison poles: number of jumpers (short wires connecting energized equipment), number of primary conductors, presence of grounding, and presence of unforested unpaved areas as the dominant nearby land cover. When tested against a sample of poles not used to build the model, our model distributed poles relatively normally across electrocution‐risk values and identified the average risk as higher for electrocution poles relative to comparison poles. Our model can be used to reduce avian electrocutions through proactive identification and targeting of high‐risk poles for retrofitting.

Modelo Predictivo del Riesgo de Electrocución de Aves en Líneas Eléctricas Elevadas
State Provision of Social Protection to International Migrants: The Relevance of Social Protection Frameworks
Authors: Swemmer Tracy
Published: September 2013

How relevant are social protection frameworks to understanding the provision of social protection to international migrants? Such frameworks have evolved against a backdrop of social protection which has been provided mainly to resident citizens, with international migrants often excluded from access. However, following an increase in remittance flows, more governments have moved to facilitate and promote migration and have extended the provision of social protection to citizens working abroad.

By examining the policies of a major labour‐sending country, the Philippines, as well as policies from other countries where migration for employment is facilitated, it becomes apparent that dominant frameworks do inform policy‐making for international migrants. The analysis shows that policies which reflect the risk management and basic needs frameworks are most common. In the case of the Philippines, the rights framework is evident in the extension of political and social rights to international migrants, an extension which is less evident elsewhere. Polices rooted in asset‐based approaches are more limited in scope, as are transformative social protection policies for migrants.

Overall, while the frameworks are potentially useful as theoretical bases, the features of the international system limit the effectiveness of the policies themselves. In addition, policies often appear to be contradictory, reflecting both the importance of ideology and the tension between the objectives of social protection for migrants and the economic imperatives of migration policy in labour‐sending countries.
Articular cartilage degeneration in the contralateral non‐surgical temporomandibular joint in mice with a unilateral partial discectomy
Authors: Cohen Wendy A. , Servais Jacqueline M. , Polur Ilona , Li Yefu , Xu Lin
Published: September 2013

Objective

The objective was to characterize the contralateral non‐surgical temporomandibular joint (TMJ) in mice that had an opposing osteoarthrosis(OA)‐like joint induced by unilateral partial discectomy.

Methods

TMJs on one side in mice were subjected to partial discectomy. Both surgical and contralateral non‐surgical TMJs were collected at 4, 8, 12 and 16 weeks post‐surgery for histological examination. The morphology of the articular cartilage of the condyle was evaluated using a scoring system.

Results

A progression of articular cartilage degeneration was seen in the TMJs following unilateral partial discectomy, including increased proteoglycan staining in the extracellular matrix at 4 weeks, the appearance of chondrocyte clusters at 8 weeks, reduced proteoglycan staining and fibrillation at 12 weeks and the loss of articular cartilage at 16 weeks. In the contralateral non‐surgical TMJs, increased proteoglycan staining occurred in the articular cartilage of the condyle at 8 weeks and continued to age.

Conclusion

The result indicated that OA‐like changes in one TMJ by partial discectomy could initiate early‐onset articular cartilage degeneration in the contralateral non‐surgical TMJ in mice.
High CDC20 expression is associated with poor prognosis in oral squamous cell carcinoma
Authors: Moura Inês M. B. , Delgado Maria L. , Silva Patrícia M. A. , Lopes Carlos A. , do Amaral José B. , Monteiro Luís S. , Bousbaa Hassan
Published: September 2013

Objectives

Human Cell Division Cycle 20 (CDC20) homolog is a crucial target of the spindle assembly checkpoint. It is an activator of the Anaphase‐Promoting Complex/Cyclosome (APC/C) which promotes anaphase onset and mitotic exit through the ubiquitination of securin and cyclin B1. Overexpression of CDC20 was previously reported in oral squamous cell carcinoma (OSCC). Here, we propose to explore the clinicopathological significance of CDC20 overexpression and its potential use as a prognostic marker in OSCC.

Methods

Using tissue microarray technology, we analyzed CDC20 expression in 65 primary OSCC tissues by immunohistochemistry. Statistical analysis was performed to evaluate the clinicopathological and prognostic significance of CDC20 expression in OSCC.

Results

Of the 65 cases of patients with OSCC studied, 37 (56.9%) showed high CDC20 protein expression. No clinicopathological features were correlated with CDC20 expression. Importantly, in univariable analysis, OSCC patients with higher CDC20 protein expression showed significantly shorter cancer‐specific survival rate (P = 0.018). Multivariable analysis identified high CDC20 expression as an independent prognostic factor (P = 0.032).

Conclusion

High CDC20 expression is associated with poor prognosis in OSCC and may be used to identify high‐risk OSCC patients and may serve as a therapeutic target.
Identification of genes for melatonin synthetic enzymes in ‘Red Fuji’ apple (Malus domestica Borkh.cv.Red) and their expression and melatonin production during fruit development
Authors: Lei Qiong , Wang Lin , Tan Dun‐Xian , Zhao Yu , Zheng Xiao‐Dong , Chen Hao , Li Qing‐tian , Zuo Bi‐xiao , Kong Jin
Published: September 2013

Melatonin is present in many edible fruits; however, the presence of melatonin in apple has not previously been reported. In this study, the genes for melatonin synthetic enzymes including tryptophan decarboxylase, tryptamine 5‐hydroxylase (T5H), arylalkylamine N‐acetyltransferase, and N‐acetylserotonin methyltransferase were identified in ‘Red Fuji’ apple. Each gene has several homologous genes. Sequence analysis shows that these genes have little homology with those of animals and they only have limited homology with known genes of rice melatonin synthetic enzymes. Multiple origins of melatonin synthetic genes during the evolution are expected. The expression of these genes is fully coordinated with melatonin production in apple development. Melatonin levels in apple exhibit an inverse relationship with the content of malondialdehyde, a product of lipid peroxidation. Two major melatonin synthetic peaks appeared on July 17 and on October 8 in both unbagged and bagged apple samples. At the periods mentioned above, apples experienced rapid expansion and increased respiration. These episodes significantly elevate reactive oxygen species production in the apple. Current data further confirmed that melatonin produced in apple was used to neutralize the toxic oxidants and protect the developing apple against oxidative stress.
Intense competition between arbuscular mycorrhizal mutualists in an in vitro root microbiome negatively affects total fungal abundance
Authors: Engelmoer Daniel J. P. , Behm Jocelyn E. , Toby Kiers E.
Published: September 2013

The root microbiome is composed of an incredibly diverse microbial community that provides services to the plant. A major question in rhizosphere research is how species in root microbiome communities interact with each other and their host. In the nutrient mutualism between host plants and arbuscular mycorrhizal fungi (AMF), competition often leads to certain species dominating host colonization, with the outcome being dependent on environmental conditions. In the past, it has been difficult to quantify the abundance of closely related species and track competitive interactions in different regions of the rhizosphere, specifically within and outside the host. Here, we used an artificial root system (in vitro root organ cultures) to investigate intraradical (within the root) and extraradical (outside the root) competitive interactions between two closely related AMF species, Rhizophagus irregularis and Glomus aggregatum, under different phosphorus availabilities. We found that competitive interactions between AMF species reduced overall fungal abundance. R. irregularis was consistently the most abundant symbiont for both intraradical and extraradical colonization. Competition was the most intense for resources within the host, where both species negatively affected each other's abundance. We found the investment ratio (i.e. extraradical abundance/intraradical abundance) shifted for both species depending on whether competitors were present or not. Phosphorus availability did not change the outcome of these interactions. Our results suggest that studies on competitive interactions should focus on intraradical colonization dynamics and consider how changes in investment ratio are mediated by fungal species interactions.
Conservation phylogeography: does historical diversity contribute to regional vulnerability in European tree frogs (Hyla arborea)?
Authors: Dufresnes Christophe , Wassef Jérôme , Ghali Karim , Brelsford Alan , Stöck Matthias , Lymberakis Petros , Crnobrnja‐Isailovic Jelka , Perrin Nicolas
Published: September 2013

Documenting and preserving the genetic diversity of populations, which conditions their long‐term survival, have become a major issue in conservation biology. The loss of diversity often documented in declining populations is usually assumed to result from human disturbances; however, historical biogeographic events, otherwise known to strongly impact diversity, are rarely considered in this context. We apply a multilocus phylogeographic study to investigate the late‐Quaternary history of a tree frog (Hyla arborea) with declining populations in the northern and western part of its distribution range. Mitochondrial and nuclear polymorphisms reveal high genetic diversity in the Balkan Peninsula, with a spatial structure moulded by the last glaciations. While two of the main refugial lineages remained limited to the Balkans (Adriatic coast, southern Balkans), a third one expanded to recolonize Northern and Western Europe, loosing much of its diversity in the process. Our findings show that mobile and a priori homogeneous taxa may also display substructure within glacial refugia (‘refugia within refugia’) and emphasize the importance of the Balkans as a major European biodiversity centre. Moreover, the distribution of diversity roughly coincides with regional conservation situations, consistent with the idea that historically impoverished genetic diversity may interact with anthropogenic disturbances, and increase the vulnerability of populations. Phylogeographic models seem important to fully appreciate the risks of local declines and inform conservation strategies.
Quantitative Structure-Activity Relationships: Linear Regression Modelling and Validation Strategies by Example
Authors: Bolboaca Sorana D. , Jäntschi Lorentz
Published: September 2013

Quantitative structure-activity relationships are mathematical models constructed based on the hypothesis that structure of chemical compounds is related to their biological activity. A linear regression model is often used to estimate and predict the nature of the relationships between a measured activity and some measure or calculated descriptors. Linear regression helps to answer main three questions: does the biological activity depend on structure information; if so, the nature of the relationship is linear; and if yes, how good is the model in prediction of the biological activity of new compounds. This manuscript presents the steps on linear regression analysis moving from theoretical knowledge to an example conducted on sets of endocrine disrupting chemicals.
Cyclic Deformation Behavior and Buckling of Pipeline With Local Metal Loss in Response to Axial Seismic Loading
Authors: Mitsuya Masaki , Motohashi Hiroyuki
Published: September 2013

Buried pipelines may be corroded, despite the use of corrosion control measures such as protective coatings and cathodic protection, and buried pipelines may be deformed due to earthquakes. Therefore, it is necessary to ensure the integrity of such corroded pipelines against earthquakes. This study has developed a method to evaluate earthquake resistance of corroded pipelines subjected to seismic motions. Pipes were subjected to artificial local metal loss and axial cyclic loading tests to clarify their cyclic deformation behavior until buckling occurred under seismic motion. As the cyclic loading progressed, displacement shifted to the compression side due to the formation of a bulge. The pipe buckled after several cycles. To evaluate the earthquake resistance of different pipelines with varying degrees of local metal loss, a finite-element analysis method was developed that simulates cyclic deformation behavior. A combination of kinematic and isotropic hardening was used to model the material properties. The associated material parameters were obtained by small specimen tests that consisted of a monotonic tensile test and a low-cycle fatigue test under a specific strain amplitude. This method enabled the successful prediction of cyclic deformation behavior, including the number of cycles required for the buckling of pipes with varying degrees of metal loss.
Critical review: Effects of complex interactions on structure and dynamics of supported metal catalysts
Authors: Frenkel Anatoly I. , Cason Michael W. , Elsen Annika , Jung Ulrich , Small Matthew W. , Nuzzo Ralph G. , Vila Fernando D. , Rehr John J. , Stach Eric A. , Yang Judith C.
Published: September 2013

This review article takes a new look at the problem of characterization of structural properties and reaction dynamics of supported metal catalysts. Such catalysts exhibit an inherent complexity, particularly due to interactions with the support and the adsorbate molecules, which can be highly sensitive to environmental conditions such as pressure and temperature. Recent reports demonstrate that finite size effects such as negative thermal expansion and large bond length disorder are directly caused by these complex interactions. To uncover the atomistic features underlying the reaction mechanisms and kinetics of metal catalysts, experimental characterization must accommodate the challenging operation conditions of catalytic processes and provide insights into system attributes. The combined application of x-ray absorption spectroscopy (XAS) and transmission electron microscopy (TEM) for this type of investigations will be examined, and the individual strengths and limitations of these methods will be discussed. Furthermore, spatial and temporal heterogeneities that describe real catalytic systems and can hinder their investigation by either averaging (such as XAS) or local (such as TEM) techniques alone will be addressed by conjoined, multiscale, ab initio density functional theory/molecular dynamics modeling of metal catalysts that can both support and guide experimental studies. When taken together, a new analysis scheme emerges, in which different forms of structure and dynamics can be fully characterized by combining information obtained experimentally by in situ XAS and electron microscopy as well as theoretically via modeling.
Metal-assisted etching of silicon molds for electroforming
Authors: Divan Ralu , Rosenthal Dan , Ogando Karim , Ocola Leonidas E. , Rosenmann Daniel , Moldovan Nicolaie
Published: September 2013

Ordered arrays of high-aspect-ratio micro/nanostructures in semiconductors stirred a huge scientific interest due to their unique one-dimensional physical morphology and the associated electrical, mechanical, chemical, optoelectronic, and thermal properties. Metal-assisted chemical etching enables fabrication of such high aspect ratio Si nanostructures with controlled diameter, shape, length, and packing density, but suffers from structure deformation and shape inconsistency due to uncontrolled migration of noble metal structures during etching. Hereby the authors prove that a Ti adhesion layer helps in stabilizing gold structures, preventing their migration on the wafer surface while not impeding the etching. Based on this finding, the authors demonstrate that the method can be used to fabricate linear Fresnel zone plates.
Superficial dosimetry imaging based on Čerenkov emission for external beam radiotherapy with megavoltage x‐ray beam
Authors: Zhang Rongxiao , Glaser Adam K. , Gladstone David J. , Fox Colleen J. , Pogue Brian W.
Published: September 2013

Purpose:

Čerenkov radiation emission occurs in all tissue, when charged particles (either primary or secondary) travel at velocity above the threshold for the Čerenkov effect (about 220 KeV in tissue for electrons). This study presents the first examination of optical Čerenkov emission as a surrogate for the absorbed superficial dose for MV x‐ray beams.

Methods:

In this study, Monte Carlo simulations of flat and curved surfaces were studied to analyze the energy spectra of charged particles produced in different regions near the surfaces when irradiated by MV x‐ray beams. Čerenkov emission intensity and radiation dose were directly simulated in voxelized flat and cylindrical phantoms. The sampling region of superficial dosimetry based on Čerenkov radiation was simulated in layered skin models. Angular distributions of optical emission from the surfaces were investigated. Tissue mimicking phantoms with flat and curved surfaces were imaged with a time domain gating system. The beam field sizes (50 × 50–200 × 200 mm2), incident angles (0°–70°) and imaging regions were all varied.

Results:

The entrance or exit region of the tissue has nearly homogeneous energy spectra across the beam, such that their Čerenkov emission is proportional to dose. Directly simulated local intensity of Čerenkov and radiation dose in voxelized flat and cylindrical phantoms further validate that this signal is proportional to radiation dose with absolute average discrepancy within 2%, and the largest within 5% typically at the beam edges. The effective sampling depth could be tuned from near 0 up to 6 mm by spectral filtering. The angular profiles near the theoretical Lambertian emission distribution for a perfect diffusive medium, suggesting that angular correction of Čerenkov images may not be required even for curved surface. The acquisition speed and signal to noise ratio of the time domain gating system were investigated for different acquisition procedures, and the results show there is good potential for real‐time superficial dose monitoring. Dose imaging under normal ambient room lighting was validated, using gated detection and a breast phantom.

Conclusions:

This study indicates that Čerenkov emission imaging might provide a valuable way to superficial dosimetry imaging in real time for external beam radiotherapy with megavoltage x‐ray beams.
Angiopoietin-1 Guides Directional Angiogenesis Through Integrin α
v
β
5
Signaling for Recovery of Ischemic Retinopathy
Authors: Lee Junyeop , Kim Kyung Eun , Choi Dong-Kyu , Jang Jeon Yeob , Jung Ji-Jung , Kiyonari Hiroshi , Shioi Go , Chang Woohyok , Suda Toshio , Mochizuki Naoki , Nakaoka Yoshikazu , Komuro Issei , Yoo Ook-Joon , Koh Gou Young
Published: September 2013

Angiopoietin-1 supplementation stimulates guided angiogenesis and promotes the formation of a healthy vascular network in a mouse model of ischemic retinopathy.
Red herring vaginal discharge
Authors: Lee Jun Hee , Pringle Kirsty , Rajimwale Ashok
Published: September 2013

Labial hair tourniquet syndrome is a rare condition that can be easily misdiagnosed and ultimately lead to irreversible damage. An 11-year-old premenarche girl presented with a 5-day history of pain and swelling in the labia with associated vaginal discharge. The general practitioner treated her with clotrimazole without improvement. On examination, there was an oedematous swelling of the right labia with a proximal hair tourniquet. Local anaesthetic was applied and the hair removed with forceps. There was instant relief of pain and the discharge stopped within 24 h. The patient was sent home with a course of antibiotics.
Evaluating the impact of air pollution on the incidence of out-of-hospital cardiac arrest in the Perth Metropolitan Region: 2000–2010
Authors: Straney Lahn , Finn Judith , Dennekamp Martine , Bremner Alexandra , Tonkin Andrew , Jacobs Ian
Published: September 2013

Background

Out-of-hospital cardiac arrest (OHCA) remains a major public health issue. Several studies have found that an increased level of ambient particulate matter (PM) smaller than 2.5 microns (PM2.5) is associated with an increased risk of OHCA. We investigated the relationship between air pollution levels and the incidence of OHCA in Perth, Western Australia.

Methods

We linked St John Ambulance OHCA data of presumed cardiac aetiology with Perth air pollution data from seven monitors which recorded hourly levels of PM smaller than 2.5 and 10 microns (PM2.5/PM10), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3). We used a case-crossover design to estimate the strength of association between ambient air pollution levels and risk of OHCA.

Results

Between 2000 and 2010, there were 8551 OHCAs that met the inclusion criteria. Of these, 5624 (65.8%) occurred in men. An IQR increase in the 24 and 48 h averages of PM2.5 was associated with 10.6% (OR 1.106, 95% CI 1.038 to 1.180) and 13.6% (OR 1.136, 95% CI 1.051 to 1.228) increases, respectively, in the risk of OHCA. CO showed a consistent association with increased risk of an OHCA. An IQR increase in the 4 h average concentration of CO was associated with a 2.2% (OR 1.022, 95% CI 1.002 to 1.042) increase in risk of an OHCA. When we restricted our analysis of CO to arrests occurring between 6:00 and 10:00, we found a 4.4% (95% CI 1.1% to 7.8%) increase in risk of an OHCA.

Conclusions

Elevated ambient PM2.5 and CO are associated with an increased risk of OHCA.
Grenvillia and Laurentia — a Precambrian Wilson cycle?
Authors: Dunlop David J.
Published: September 2013

John Tuzo Wilson coined the term “plate” in plate tectonics. He is famous for inventing transform boundaries, hot spot tracks, and the Wilson cycle of ocean birth, growth, and decline. Less well remembered is his work in the 1950s on tectonic and radiometric age provinces of the Canadian Shield, as part of which he fathered U/Pb geochronology in Canada. This work gave strong support to the notion of continental growth through accretion of successively younger terranes onto an ancient cratonic core. The present paper reviews how paleomagnetism can trace the motions of continents to test Wilson’s ideas. Continental accretion often involves deep burial of one of the colliding elements through subduction or crustal underplating; such was the case with the Grenville orogen and its subprovinces in their Proterozoic accretion onto the Laurentian craton. The resulting heating and metamorphism erases most pre-collisional magnetic information but adds something new: the possibility of following the post-metamorphic uplift and cooling history, in time and space. The time element is provided by a new form of isotopic geochronology, thermochronometry, which provides dates for specific minerals together with the temperatures at which they became closed to isotopic migration. U/Pb dating of sphene is one method used; another is the 40Ar/39Ar variant of K/Ar dating applied to hornblende, micas, and feldspars, which have a wide range of Ar closure temperatures. The two specific Grenville studies described deal with parallel uplift histories determined by 40Ar/39Ar dating and by magnetics for the accreted terranes of the Central Metasedimentary Belt in Ontario and with the paleomagnetic detection of the post-1240 Ma closing of a small ocean between the Elsevir terrane and Laurentia during the Grenvillian orogeny.
ATTRACTING DOMAINS OF MAPS TANGENT TO THE IDENTITY WHOSE ONLY CHARACTERISTIC DIRECTION IS NON-DEGENERATE
Authors: LAPAN SARA W.
Published: September 2013

Let f be a holomorphic germ on ℂ2 that fixes the origin and is tangent to the identity. Assume that f has a non-degenerate characteristic direction [v]. Hakim gave conditions that guarantee the existence of attracting domains along [v], however, when f has only one characteristic direction, these conditions are not satisfied. We prove that when [v] is unique, the existence results still hold. In particular, there is a domain Ω whose points converge to the origin along [v] and, on Ω, f is conjugate to a translation. Furthermore, if f is a global automorphism, the corresponding domain of attraction is a Fatou–Bieberbach domain.
Cellular automaton simulations of a four-leg intersection with two-phase signalization
Authors: Jin Cheng-Jie , Wang Wei , Jiang Rui , Wang Hao
Published: September 2013

In this paper, we present a cellular automaton (CA) simulation of a signalized intersection. When there is no exclusive lane for left-turn vehicles, through vehicles and left-turn vehicles have to share one lane. Under such situation usually two-phase signalization is adopted, and the conflicts between the two traffic streams need to be analyzed. We use a refined configuration for the intersection simulation: the geometry of the intersection has been considered and vehicles are assumed to move along 1/4 circle arcs. We focus on the averaged travel times on left lanes and their distributions. The diagrams of intersection approach capacities (IACs) and the corresponding phase diagrams are also presented, which depend on the approach flow rates and the percentage of left-turn vehicles. Besides, we find that the minimum green time could be determined by finding out the critical value for the travel times.
GÖDEL SOLUTION IN f(R, T) GRAVITY
Authors: SANTOS A. F.
Published: September 2013

In this paper, we study Gödel universe in the framework of f(R, T) modified theories of gravity, where R is the curvature scalar and T the trace of the energy–momentum tensor. We demonstrate that Gödel solution occurs in this modified theory and still we suggest a path to understanding the smallness of the cosmological constant.
TURBULENT INSTABILITY OF ANTI-DE SITTER SPACE–TIME
Authors: MALIBORSKI MACIEJ , ROSTWOROWSKI ANDRZEJ
Published: September 2013

In these lecture notes, we discuss recently conjectured instability of anti-de Sitter space, resulting in gravitational collapse of a large class of arbitrarily small initial perturbations. We uncover the technical details used in the numerical study of spherically symmetric Einstein-massless scalar field system with negative cosmological constant that led to the conjectured instability.
CANONICAL-DISSIPATIVE NONEQUILIBRIUM ENERGY DISTRIBUTIONS: PARAMETER ESTIMATION VIA IMPLICIT MOMENT METHOD, IMPLEMENTATION AND APPLICATION
Authors: FRANK T. D. , KIM S. , DOTOV D. G.
Published: September 2013

Canonical-dissipative nonequilibrium energy distributions play an important role in the life sciences. In one of the most fundamental forms, such energy distributions correspond to two-parametric normal distributions truncated to the left. We present an implicit moment method involving the first and second energy moments to estimate the distribution parameters. It is shown that the method is consistent with Cohen's 1949 formula. The implementation of the algorithm is discussed and the range of admissible parameter values is identified. In addition, an application to an earlier study on human oscillatory hand movements is presented. In this earlier study, energy was conceptualized as the energy of a Hamiltonian oscillator model. The canonical-dissipative approach allows for studying the systematic change of the model parameters with oscillation frequency. It is shown that the results obtained with the implicit moment method are consistent with those derived in the earlier study by other means.
MODEL IMPERFECTION AND PREDICTING PREDICTABILITY
Authors: MACHETE REASON L.
Published: September 2013

It has been argued that Lyapunov exponents as a measure of predictability are of limited value because they only provide a global average. Characterizing an attractor by a distribution of times for initial uncertainties to increase by a factor of q has been suggested as a more useful alternative. These have found favor in some applications, despite assumptions of the fictitious perfect model scenario. Here, an electronic circuit, which offers a good test-bed for addressing predictability in the imperfect model scenario, is presented. A novel measure of predictability is presented and implications of model imperfection on characterizing the dynamics of chaotic systems are discussed. It is a case for a multiple model approach.
THE BUNDLE PLOT: EVOLUTION OF SYMBOLIC SPACE UNDER THE SYSTEM PARAMETER CHANGES
Authors: ZHENG JIONGXUAN , SKUFCA JOSEPH D. , BOLLT ERIK M.
Published: September 2013

This paper provides a topological dynamics perspective on the full bifurcation unfolding in unimodal mappings. We present a bundle structure, visualized as a bundle plot, to show the evolution of symbolic space as we vary a system parameter. The bundle plot can be viewed as a limit process of an assignment plot, which are line assignments between points from two dynamical systems. Such line assignments are determined by a commuter, which is a coordinates transformation function that satisfies a commuting relationship but not necessarily a homeomorphism. The bundle structure is studied by understanding the implication of the system's qualitative changes. In addition, the case of the bundle plot with higher dimensional parameter variation is also considered. A main concern in the bundle plot is a special structure, called "joint", which determines a critical value of the parameter where the kneading sequence becomes periodic.
BIFURCATION, CHAOS AND THEIR CONTROL IN A TIME-DELAY DIGITAL TANLOCK LOOP
Authors: BANERJEE TANMOY , PAUL BISHWAJIT , SARKAR B. C.
Published: September 2013

This paper reports the detailed parameter space study of the nonlinear dynamical behaviors and their control in a time-delay digital tanlock loop (TDTL). At first, we explore the nonlinear dynamics of the TDTL in parameter space and show that beyond a certain value of loop gain parameter the system manifests bifurcation and chaos. Next, we consider two variants of the delayed feedback control (DFC) technique, namely, the time-delayed feedback control (TDFC) technique, and its modified version, the extended time-delayed feedback control (ETDFC) technique. Stability analyses are carried out to find out the stable phase-locked zone of the system for both the controlled cases. We employ two-parameter bifurcation diagrams and the Lyapunov exponent spectrum to explore the dynamics of the system in the global parameter space. We establish that the control techniques can extend the stable phase-locked region of operation by controlling the occurrence of bifurcation and chaos. We also derive an estimate of the optimum parameter values for which the controlled system has the fastest convergence time even for a larger acquisition range. The present study provides a necessary detailed parameter space study that will enable one to design an improved TDTL system.