bluuebunny/crossref_metadata_2025 huggingface dataset:
Niche breadth of oligarchic species in Amazonian and Andean rain forests
Authors: Arellano Gabriel , Cala Victoria , Macía Manuel J.
Published: April 2014

Aim

To test the niche breadth hypothesis (NBH), which states that dominant species have broader environmental tolerances than rare species, focusing on oligarchic species distributions (1) along the gradients of edaphic and climatic individual variables, and (2) within the n‐dimensional environmental frame defined by all edaphic and climatic variability.

Location

Amazonian and Andean tropical rain forests along a ca. 3000 m elevation gradient, covering an area of 200 × 200 km in northwestern Bolivia.

Methods

All woody plants with a DBH ≥2.5 cm were measured in 98 0.1‐ha plots. We analysed 18 chemical properties of the soils in each plot. Climatic and topographic variables were obtained from available open‐access databases. Three measures were calculated for each of the species found at each forest type: (1) regional‐scale dominance based on frequency and local abundance, (2) niche breadth along each of the environmental variables, and (3) total niche size within the whole environment.

Results

Oligarchic species showed broader niche breadths than the other species that constituted the community assembly in both Amazonian and Andean rain forests. The niche breadth of any species tended to be positively correlated with its degree of dominance. The Amazonian forest showed a stronger oligarchic pattern than the Andean forest, and the Amazonian common species showed larger niches overall. However, this pattern differed for some particular variables: Amazonian oligarchies had narrower niches along the variables related to organic matter and most climatic variables, whereas Andean oligarchies had narrower niches along several micronutrient factors and temperature variables.

Conclusions

The results provide strong empirical support for the NBH in tropical rain forests. However, different patterns of dominance were found in the two habitats: oligarchic species ranged from narrow‐niched species to very broad generalist species. Broad‐niched oligarchic species have also been reported in other regions, suggesting an important role of niche size linking commonness at different scales. Oligarchic species exhibit relatively narrow niches with respect to soil factors if measured along wide gradients, regardless of the forest type studied. In contrast, the opposite pattern was found for many climatic variables, indicating higher sensitivity to climate in Amazonia compared to the Andes. Despite these differences, Amazonia has much larger total niche sizes for its common species than the Andes overall.
Recent speciation and secondary contact in endemic ants
Authors: Jowers Michael J. , Amor Fernando , Ortega Patrocinio , Lenoir Alain , Boulay Raphaël R. , Cerdá Xim , Galarza Juan A.
Published: April 2014

Gene flow is the main force opposing divergent selection, and its effects are greater in populations in close proximity. Thus, complete reproductive isolation between parapatric populations is not expected, particularly in the absence of ecological adaptation and sharp environmental differences. Here, we explore the biogeographical patterns of an endemic ant species, Cataglyphis floricola, for which two colour morphs (black and bicolour) coexist in parapatry throughout continuous sandy habitat in southern Spain. Discriminant analyses of six biometric measurements of male genitalia and 27 cuticular hydrocarbons reveal high differentiation between morphs. Furthermore, the low number of shared alleles derived from nuclear markers (microsatellites) between the morphs at their contact zone suggests the absence of recent gene flow. Mitochondrial DNA (COI) phylogenetic analysis and median‐joining networks show that the black morph is basal to the bicolour morph, with unique haplotypes recovered for each morph. Mismatch distribution analysis and Bayesian skyline plots suggest that they are undergoing different demographic changes, with the bicolour and black morphs at demographic equilibrium and expansion, respectively. Thus, our results show complete reproductive isolation between the two colour morphs as evidenced from genetic, chemical and morphological data. We suggest that these divergence events could be explained by historical vicariance during the Pleistocene, in which reproductive traits experienced strong divergent selection between the morphs initiating or culminating speciation.
Didymocarpus tonghaiensis sp. nov. (Gesneriaceae) from Yunnan, China
Authors: Li J. M. , Wang F. S.
Published: April 2014

Didymocarpus tonghaiensis J. M. Li & F. S. Wang sp. nov. from Yunnan, China, is illustrated and described. It is morphologically similar to D. stenanthos C. B. Clarke, but differs by having a densely glandular peduncle, 5‐lobed calyx with lobes that are free to the base, larger corolla, anther with white woolly hairs and a densely glandular‐hairy capsule.
The diversity–stability relationship in floral production
Authors: Dorado Jimena , Vázquez Diego P.
Published: April 2014

The diversity–stability hypothesis posits that species diversity confers redundancy in function, so that richer communities show higher temporal stability in ecosystem processes than poorer communities. The diversity–stability relationship has not been studied in terms of flower production before. A diverse flower community may stabilize the availability of floral resources along the floral season. Considering this type of stability is important because it could promote the stability and persistence of the pollination service. We evaluated 1) the diversity–stability relationship in floral production along a flowering season; 2) the effect of additional factors that could blur the diversity–stability relationship, such as flower abundance, elevation, and the time elapsed since the last fire, a common human disturbance in the study area; and 3) whether the most important plants for pollinators in terms of interspecific interactions contribute differentially to temporal stability. The most diverse communities were more stable in floral resource production along the flowering season. Stability of flower production was also influenced by a positive indirect effect of elevation. The plants that contributed the most to temporal stability were the most abundant and densely connected species, those at the core of the plant–pollinator network. Our study shows that species richness enhances the availability of floral resources for pollinators, providing a strong support for the diversity–stability hypothesis.
Parameters of the Reproductive Tract, Spermatogenesis, Daily Sperm Production and Major Seminal Plasma Proteins of Tropically Adapted Morada Nova Rams
Authors: Sousa FML , Lobo CH , Menezes ESB , Rego JPA , Oliveira RV , Lima‐Souza AC , Fioramonte M , Gozzo FC , Pompeu RCFF , Cândido MJD , Oliveira JT , Moura AA
Published: April 2014

Contents

This study describes the reproductive parameters of Morada Nova rams, a breed of hair sheep from Brazil and with unique adaption to tropical environments. At 42 weeks of age, 15 rams were subjected to semen collection and, 1 week later, animals were slaughtered for collection of testes, epididymis and accessory sex glands. We conducted 2‐D electrophoresis of seminal plasma proteins and major spots of stained gels were identified by LC‐MS/MS. Total RNA was isolated from testis, epididymis and vesicular glands and subjected to qPCR. At slaughter, scrotal circumference and testicular weight were 27.5 ± 0.5 cm and 109.5 ± 6.0 g, respectively. Seminiferous tubule (ST) diameter was 188.3 ± 4.0 μm and each testis contained 1.9 ± 0.1 Sertoli cells (×109). Each Sertoli cell supported 0.1 ± 0.01 A spermatogonia, 3.0 ± 0.2 pachytene spermatocytes and 7.7 ± 0.5 round spermatids/tubule cross section. Daily sperm production reached 5.6 × 106 cells/g of testis parenchyma. Testis size appeared as indicative of ST diameter and associated with epididymal measurements, as well as with the population of round spermatids and Sertoli cells/testis. Rams with heavier testes had greater daily sperm production and more Sertoli cells/testis. We detected 90.9 ± 9.6 spots per 2‐D gel of seminal plasma. Major seminal proteins were identified as ram seminal vesicle proteins at 14 and 22 kDa, representing 16.2% and 12.8% of the total intensity of valid spots in the gels, respectively. Expression of both genes was greater in the vesicular glands as compared to testis and epididymis. Pixel intensity for those proteins in the 2‐D gels was significantly correlated with seminal vesicle weight. This is the first description of the basic reproductive aspects of Morada Nova rams, including protein profiles of their seminal plasma. These findings will allow a better understanding of their reproductive physiology.
Towards Uniformly Efficient Trend Estimation Under Weak/Strong Correlation and Non‐stationary Volatility
Authors: Xu Ke‐Li , Yang Jui‐Chung
Published: April 2014

In this paper, we consider the deterministic trend model where the error process is allowed to be weakly or strongly correlated and subject to non‐stationary volatility. Extant estimators of the trend coefficient are analysed. We find that under heteroskedasticity, the Cochrane–Orcutt‐type estimator (with some initial condition) could be less efficient than Ordinary Least Squares (OLS) when the process is highly persistent, whereas it is asymptotically equivalent to OLS when the process is less persistent. An efficient non‐parametrically weighted Cochrane–Orcutt‐type estimator is then proposed. The efficiency is uniform over weak or strong serial correlation and non‐stationary volatility of unknown form. The feasible estimator relies on non‐parametric estimation of the volatility function, and the asymptotic theory is provided. We use the data‐dependent smoothing bandwidth that can automatically adjust for the strength of non‐stationarity in volatilities. The implementation does not require pretesting persistence of the process or specification of non‐stationary volatility. Finite‐sample evaluation via simulations and an empirical application demonstrates the good performance of proposed estimators.
Conyza sumatrensis: A new weed species resistant to glyphosate in the Americas
Authors: Santos Gizelly , Oliveira Rubem S. , Constantin Jamil , Constantin Francischini Alessandra , Machado Maria F.P.S. , Mangolin Claudete A. , Nakajima Jimi N.
Published: April 2014

Recent reports of weed‐control failures after the use of glyphosate led to suspicion about the selection of resistant biotypes of Conyza at locations in west and north Paraná, Brazil. Plants were collected, identified as Conyza sumatrensis and subsequently evaluated for possible resistance to glyphosate in four stages of weed development. The experiments were carried out in a greenhouse by combining biotypes, stages of development and a range of glyphosate doses. All the suspected biotypes were collected from locations in Cascavel, Toledo, Assis Chateaubriand, Tupãssi and Campo Mourão with a history of glyphosate use in burndown and in glyphosate‐resistant soybean for at least the four previous years and were compared to a susceptible biotype (São Jorge do Ivaí) with no previous history of herbicide use. The doses of glyphosate ranged from 0 to 5760 g ae ha−1. The biotypes were considered as resistant if two combined criteria were present (resistance factor > 1 and the rate required to achieve 80% control is >720 g ha−1). The results provided evidence that there is a marked difference in the level of control of older plants and also confirmed the presence of some resistant biotypes. For applications at the first stage of development, two biotypes that were resistant to glyphosate were identified (Cascavel‐1 and Tupãssi‐6). For applications in the second stage of development, beyond the biotypes that were found in the first stage, three other biotypes were considered as resistant: Toledo‐5, Assis Chateaubriand‐7 and Floresta‐10. However, for applications at the third and fourth stages, all the biotypes were considered as resistant.
Biological control of Rumex obtusifolius and Rumex crispus by goat grazing
Authors: Hejcman Michal , Strnad Lukáš , Hejcmanová Pavla , Pavlů Vilém
Published: April 2014

Rumex obtusifolius and Rumex crispus are problematic grassland weedy species, particularly under conditions of organic farming. They are avoided by cattle and horses, but they can be grazed by goats. The aim of this study was to investigate the effectiveness of continuous goat grazing of moderate intensity on R. obtusifolius and R. crispus control. In 2008, 40 seedlings of each species were transplanted into pasture that was grazed by goats (crossbreed Czech white × Czech brown) on the target sward height of 7–10 cm. The number of leaves, proportion of grazed leaves and mortality of plants were monitored over the following 4 years. The number of leaves per plant was higher for R. obtusifolius than for R. crispus. The maximal number of leaves per plant of R. obtusifolius and R. crispus was 10 and 5, respectively. The proportion of grazed leaves was generally higher for R. obtusifolius than for R. crispus and ranged from 10% to 80%. No fertile plant was recorded during the experiment, as goat grazing totally prevented the flowering of both species. The level of mortality of the plants at the start of the fourth grazing season was 70% and 87% for R. obtusifolius and R. crispus, respectively, and no plant survived the fourth grazing season. It was concluded that continuous goat grazing of a moderate intensity that is carried out over 4 years seems to be an effective method for the non‐chemical control of R. obtusifolius and R. crispus in grassland.
Identifying the problem weeds of rice‐based systems along the inland‐valley catena in the southern Guinea Savanna, Africa
Authors: Touré Amadou , Rodenburg Jonne , Marnotte Pascal , Dieng Ibnou , Huat Joël
Published: April 2014

While weeds generally are considered as the most important overarching production constraints in inland‐valley cropping systems in West Africa, little is known about species' associations with environmental and crop management factors. Weed species' associations with seasonal and environmental factors, such as their position on the catena, soils and cropping systems, were studied during two seasons (dry and wet) in 45 arable fields of three inland valleys in south‐western Benin, Africa. The three most dominant weed species were Dactyloctenium aegyptium, Commelina benghalensis and Digitaria horizontalis on the inland‐valley crests (uplands), Ludwigia hyssopifolia, Corchorus aestuans and Ludwigia octovalvis on the sloping hydromorphic fringes and Leersia hexandra, Ipomoea aquatica and Fimbristylis ferruginea in the valley bottoms (lowlands). Echinochloa colona, Cleome viscosa and Talinum triangulare were the three most dominant species in the dry‐season crops (maize or vegetables) and Leer. hexandra, I. aquatica and Sphenoclea zeylanica were the three most dominant species in the wet‐season crop (rice). Ageratum conyzoides, Synedrella nodiflora and D. horizontalis were observed throughout the catena. Problem weeds in inland‐valley agro‐ecosystems are those that combine a high frequency with a high submergence tolerance and ecological plasticity, C4 grasses, perennial C3 species with persistent root structures and broad‐leaved species with high propagation rates. Weed management strategies that are aimed at increasing the resilience of rice‐based cropping systems in the inland valleys of the southern Guinea Savanna of Africa should address the categories of problem species that were identified in this study. This can be done best by following an integrated approach, including the use of more weed‐competitive cultivars and rotation crops.
Fabrication and characterization of composite hydrogel particles with x-ray attenuating payloads
Authors: Wang Congshun , Wang Xiaoning , Zhang Xin , Anderson Stephan
Published: April 2014

This paper reports the fabrication and characterization of composite hydrogel particles composed of poly(ethylene glycol) diacrylate (PEG-DA)-based hydrogels and x-ray attenuating payloads. The top–down fabrication method employed herein is demonstrated to yield composite hydrogel particles of varying size and shape for use as computed tomography (CT) imaging contrast agents. Characterization of the materials properties of the PEG-DA hydrogels was undertaken, demonstrating tunable mechanical properties of composite hydrogels based on hydrogel composition and UV cross-linking time. Analyses of the leakage rates of a conventional iodine-based small molecular contrast agent as well as a nanoparticulate x-ray attenuating material from the PEG-DA hydrogels were undertaken. In contradistinction to clinically available iodinated CT contrast agents, as well as recently developed nanoparticulate CT contrast agents, the approach presented herein yields an engineering flexibility to the design of CT contrast agents which may be leveraged to optimize this class of agents to a wide array of specific imaging and sensing applications.
Exercise Intolerance and the Impact of Physical Activity in Children Treated With Hematopoietic Stem Cell Transplantation
Authors: West Sarah L. , Gassas Adam , Schechter Tal , Egeler R. Maarten , Nathan Paul C. , Wells Greg D.
Published: April 2014

Hematopoietic stem-cell transplant (SCT) is increasingly used to treat children with cancer, and survival following SCT is improving. One predominant consequence of childhood cancer therapy is increased physical morbidity, which is worse in pediatric SCT recipients compared with children treated with chemotherapy or radiation alone. There are many factors that contribute to exercise intolerance and reduced physical function during the pretransplant, peritransplant, and posttransplant phases. These include side effects from chemotherapy or radiation, excessive immobility due to bed rest, infections, the negative effects of immunosuppressants, and graft vs host disease, all of which can impair cardiorespiratory fitness, muscle strength, and muscle function. Few studies have investigated the effects of exercise in childhood SCT recipients. In a small number of published studies, exercise interventions have been demonstrated to improve cardiorespiratory fitness, preserve or increase muscle mass, and improve muscle strength in children following SCT. The use of exercise as medicine may be a noninvasive and nonpharmaceutical treatment to target physical complications post-SCT. Researchers and health-care professionals should work together to develop exercise prescription guidelines for this unique and important population.
A Critical Period Defined by Axon-Targeting Mechanisms in the Murine Olfactory Bulb
Authors: Tsai Lulu , Barnea Gilad
Published: April 2014

Axon Routing in the Olfactory System

The olfactory system of mice entails a developmental program that wires neurons expressing similar olfactory receptors into glomeruli together. Although the adult olfactory system continues to produce and incorporate new neurons, it cannot withstand severe damage (see the Perspective by

Cheetham and Belluscio

).

Ma
et al.

(p.
194
) and
Tsai and Barnea
(p.
197
) examined the difference in responses between early development and adulthood. Manipulating the expression of an odorant receptor or the activity of the olfactory neurons altered olfactory neuron axonal pathfinding. The results suggest that the guidance systems used differ between early development and adulthood: Early axons find their own way, but later-in-life axons can only follow existing pathways.
Unlikely Yet Pivotal Long Dispersals
The Monkey's Voyage
How Improbable Journeys Shaped the History of Life

by Alan de Queiroz

Basic Books, New York, 2014. 368 pp. $27.99, C$31. ISBN 9780465020515.
Authors: Nathan Ran , Nathan Oz
Published: April 2014

De Queiroz argues for the importance of oceans as biogeographic highways as well as barriers.
NASA to Researchers: Sell Your Mission or Be Terminated
Authors: Kerr Richard A.
Published: April 2014

Researchers running six NASA planetary science missions are competing for funds to keep their spacecraft alive.
Mesoamerica's Mystery Killer
Authors: Cohen Jon
Published: April 2014

Scientists have come up with a gallery of rogues to explain an epidemic of kidney disease in Central America. But the culprit has stayed one step ahead.
Simple, Low-Cost Molecular Assays for TR
34
/L98H Mutations in the
cyp51A
Gene for Rapid Detection of Triazole-Resistant Aspergillus fumigatus Isolates
Authors: Ahmad Suhail , Khan Ziauddin , Hagen Ferry , Meis Jacques F.
Published: April 2014

Simple, low-cost PCR/PCR-restriction fragment length polymorphism (RFLP) assays targeting
cyp51A
promoter and codon 98 regions were developed for the detection of triazole-resistant
Aspergillus fumigatus
strains carrying TR
34
/L98H mutations. The assays were evaluated using 40 itraconazole-susceptible isolates and 35 itraconazole-resistant isolates. The prevalence of TR
34
/L98H mutations in clinical/environmental
A. fumigatus
isolates may now be determined easily from resource-poor settings.
Multicenter Evaluation of the New Vitek 2 Yeast Susceptibility Test Using New CLSI Clinical Breakpoints for Fluconazole
Authors: Pfaller M. A. , Diekema D. J. , Procop G. W. , Wiederhold N. P.
Published: April 2014

A fully automated antifungal susceptibility test system recently updated to reflect the new species-specific clinical breakpoints (CBPs) of fluconazole forCandida(Vitek 2 AF03 yeast susceptibility test; bioMérieux, Inc., Durham, NC) was compared in three different laboratories with the Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution (BMD) method by testing 2 quality control strains, 10 reproducibility strains (4Candidaspecies and 6Cryptococcus neoformansstrains), and 746 isolates ofCandidaspecies (702 isolates, 13 species) and 44 isolates ofC. neoformansagainst fluconazole. Excellent essential agreement (EA) (within 2 dilutions) between the reference and Vitek 2 MICs was observed for fluconazole andCandidaspecies (94.0%). The EA was lower for fluconazole andC. neoformansat 86.4%. The mean times to a result with the Vitek 2 test were 9.1 h forCandidaspecies and 12.1 h forC. neoformans. Categorical agreement (CA) between the two methods was assessed by using the new species-specific CBPs. For less common species without fluconazole CBPs, the epidemiological cutoff values (ECVs) were used to differentiate wild-type (WT; MIC, ≤ECV) from non-WT (MIC, >ECV) strains. The CAs between the two methods were 92.0% forCandidaspecies (0.3% very major errors [VME] and 2.6% major errors [ME]) and 84.1% forC. neoformans(4.5% VME and 11.4% ME). The updated Vitek 2 AF03 IUO yeast susceptibility system is comparable to the CLSI BMD reference method for testing the susceptibility of clinically important yeasts to fluconazole when using the new (lower) CBPs and ECVs.
Development of a High-Yield Live Attenuated H7N9 Influenza Virus Vaccine That Provides Protection against Homologous and Heterologous H7 Wild-Type Viruses in Ferrets
Authors: Chen Zhongying , Baz Mariana , Lu Janine , Paskel Myeisha , Santos Celia , Subbarao Kanta , Jin Hong , Matsuoka Yumiko
Published: April 2014

Live attenuated H7N9 influenza vaccine viruses that possess the hemagglutinin (HA) and neuraminidase (NA) gene segments from the newly emerged wild-type (wt) A/Anhui/1/2013 (H7N9) and six internal protein gene segments from the cold-adapted influenza virus A/Ann Arbor/6/60 (AA
ca
) were generated by reverse genetics. The reassortant virus containing the original wt A/Anhui/1/2013 HA and NA sequences replicated poorly in eggs. Multiple variants with amino acid substitutions in the HA head domain that improved viral growth were identified by viral passage in eggs and MDCK cells. The selected vaccine virus containing two amino acid changes (N133D/G198E) in the HA improved viral titer by more than 10-fold (reached a titer of 10
8.6
fluorescent focus units/ml) without affecting viral antigenicity. Introduction of these amino acid changes into an H7N9 PR8 reassortant virus also significantly improved viral titers and HA protein yield in eggs. The H7N9
ca
vaccine virus was immunogenic in ferrets. A single dose of vaccine conferred complete protection of ferrets from homologous wt A/Anhui/1/2013 (H7N9) and nearly complete protection from heterologous wt A/Netherlands/219/2003 (H7N7) challenge infection. Therefore, this H7N9 live attenuated influenza vaccine (LAIV) candidate has been selected for vaccine manufacture and clinical evaluation to protect humans from wt H7N9 virus infection.

IMPORTANCE
In response to the recent avian H7N9 influenza virus infection in humans, we developed a live attenuated H7N9 influenza vaccine (LAIV) with two amino acid substitutions in the viral HA protein that improved vaccine yield by 10-fold in chicken embryonated eggs, the substrate for vaccine manufacture. The two amino acids also improved the antigen yield for inactivated H7N9 vaccines, demonstrating that this finding could great facilitate the efficiency of H7N9 vaccine manufacture. The candidate H7N9 LAIV was immunogenic and protected ferrets against homologous and heterologous wild-type H7 virus challenge, making it suitable for use in protecting humans from H7 infection.
A Single Amino Acid Mutation (I1012F) of the RNA Polymerase of Marine Viral Hemorrhagic Septicemia Virus Changes
In Vitro
Virulence to Rainbow Trout Gill Epithelial Cells
Authors: Kim Sung-Hyun , Thu Beate J. , Skall Helle F. , Vendramin Niccolò , Evensen Øystein
Published: April 2014

Viral hemorrhagic septicemia virus (VHSV) is separated into four different genotypes (I to IV) with different sublineages (K. Einer-Jensen, P. Ahrens, R. Forsberg, and N. Lorenzen, J. Gen. Virol. 85:1167–1179, 2004; K. Einer-Jensen, J. Winton, and N. Lorenzen, Vet. Microbiol. 106:167–178, 2005). European marine VHSV strains (of genotypes I to III) are, in general, nonpathogenic or have very low pathogenicity to rainbow trout after a waterborne challenge, and here we also show that genotype IVa is nonpathogenic to trout. Despite several attempts, it has not been possible to link genomic variation to
in vivo
virulence.
In vitro
virulence to gill epithelial cells (GECs) has been used as a proxy for
in vivo
virulence, and here we extend these studies further with the purpose of identifying residues associated with
in vitro
virulence. Genotype Ia (DK-3592B) and III (NO/650/07) isolates, which are pathogenic to rainbow trout (O. B. Dale, I. Orpetveit, T. M. Lyngstad, S. Kahns, H. F. Skall, N. J. Olesen, and B. H. Dannevig, Dis. Aquat. Organ. 85:93–103, 2009), were compared to two marine strains that are nonpathogenic to trout, genotypes Ib (strain 1p8 [H. F. Mortensen, O. E. Heuer, N. Lorenzen, L. Otte, and N. J. Olesen, Virus Res. 63:95–106, 1999]) and IVa (JF-09). DK-3592 and NO/650/07 were pathogenic to GECs, while marine strains 1p8 and JF-09 were nonpathogenic to GECs. Eight conserved amino acid substitutions contrasting high- and low-virulence strains were identified, and reverse genetics was used in a gain-of-virulence approach based on the JF-09 backbone. Mutations were introduced into the G, NV, and L genes, and seven different virus clones were obtained. For the first time, we show that a single amino acid mutation in conserved region IV of the L protein, I1012F, rendered the virus able to replicate and induce a cytopathic effect in trout GECs. The other six mutated variants remained nonpathogenic.

IMPORTANCE
This is the first study to clearly link
in vitro
virulence of viral hemorrhagic septicemia virus (VHSV) with an amino acid residue in the L protein, a site located in conserved region IV of the L protein.
In vitro
virulence is documented by induction of cytopathic effects and viability studies of gill epithelial cells, and the observed cellular responses to infection are associated with increased viral replication levels. There are no previous studies addressing the importance of the L protein or the RNA-dependent RNA polymerase for virus virulence
in vitro
or
in vivo
. Therefore, the findings reported here should broaden the search for pathogenicity traits in novirhabdoviruses, and there is a possibility that the polymerase participates in defining the host species virulence of various VHSV strains.
Kaposi's Sarcoma-Associated Herpesvirus ORF45 Mediates Transcriptional Activation of the HIV-1 Long Terminal Repeat via RSK2
Authors: Karijolich John , Zhao Yang , Peterson Bret , Zhou Qiang , Glaunsinger Britt
Published: April 2014

Robust activation of human immunodeficiency virus type 1 (HIV-1) gene expression occurs upon superinfection with Kaposi's sarcoma-associated herpesvirus (KSHV), a common AIDS-associated pathogen. Though the mechanisms underlying this phenotype remain unknown, several KSHV-encoded factors have been reported to stimulate HIV-1 long terminal repeat (LTR) activity. Here, we systematically evaluated the ability of KSHV tegument proteins to modulate the activation of an integrated HIV-1 LTR and revealed that the most potent individual activator is ORF45. ORF45 directs an increase in RNA polymerase II recruitment to the HIV-1 LTR, leading to enhanced transcriptional output. ORF45 is a robust activator of the p90 ribosomal S6 kinases (RSK), and we found that this activity is necessary but not sufficient to increase transcription from the LTR. Of the three widely expressed RSK isoforms, RSK2 appears to be selectively involved in LTR stimulation by both KSHV ORF45 and HIV-1 Tat. However, constitutively active RSK2 is unable to stimulate the LTR, suggesting that ORF45 may preferentially direct this kinase to a specific set of targets. Collectively, our findings reveal a novel transcriptional activation function for KSHV ORF45 and highlight the importance of RSK2 in shaping the transcriptional environment during infection.

IMPORTANCEKaposi's sarcoma-associated herpesvirus (KSHV) is a prominent AIDS-associated pathogen. Previous studies have shown that infection of cells containing human immunodeficiency virus type 1 (HIV-1) with KSHV leads to potent stimulation of HIV-1 gene expression by activating the HIV-1 promoter, termed the long terminal repeat (LTR). Here, we compared the abilities of various KSHV proteins to activate gene expression from the HIV-1 LTR and found that KSHV ORF45 is the most potent activator. ORF45 is known to induce cell signaling through ribosomal S6 kinase (RSK) and enhance protein translation. However, we revealed that the activation of a specific isoform of RSK by ORF45 also leads to increased mRNA synthesis from the LTR by the host RNA polymerase. Collectively, our findings provide new insight into the interviral interactions between KSHV and HIV that may ultimately impact disease.
Sodium valproate-related hyperammonaemic encephalopathy
Authors: Pegg Emily Jane , Zaman Fawad
Published: April 2014

A 59-year-old man with a background of poststroke epilepsy, lung cancer, chronic obstructive pulmonary disease and hypertension, presented to the medical assessment unit with acute confusion and altered consciousness. Medications included sodium valproate, aspirin and antihypertensives. On examination he was confused, with his Glasgow Coma Scale fluctuating between 10 and 14. Routine blood tests, thyroid function tests, serum sodium valproate level, urine dip, CT of the brain and cerebrospinal fluid analysis were all normal. EEG revealed changes consistent with an encephalopathic process. Serum ammonia was elevated (75 µg/dL), consistent with a diagnosis of valproate-related hyperammonaemic encephalopathy. Sodium valproate was changed to a different antiepileptic drug and his confusion gradually resolved. Valproate-related hyperammonaemic encephalopathy is a treatable condition which should be considered as a diagnosis in anyone taking sodium valproate with new onset confusion, even in the presence of therapeutic sodium valproate levels and normal liver function tests.
Influence of valley geometry on stability of an earth dam
Authors: Chugh Ashok K.
Published: April 2014

Influence of valley geometry on stability of an earth dam is assessed in terms of its static slope stability. Numerical model results for an earth dam sited in a trapezoidal valley are presented for two combinations of dam crest length and valley floor width. In one combination, the valley floor width is held constant and the slope of valley walls is varied; in the second combination, the dam crest length is held constant and the slope of valley walls is varied. The results for the two combinations are not the same. The results presented are from three-dimensional (3-D) and two-dimensional (2-D) continuum-mechanics-based numerical analyses and are in terms of factor of safety (FoS) and associated slip surface. Significant results include: (i) influence of valley geometry on FoS is minimal when valley floor width exceeds about five times the dam height; and (ii) ratio of 3-D to 2-D FoS can be in the range of 1.03 to 1.30 depending on the valley geometry. Practical implications of the results are included.
Density functional theory study of bis(imino) N-heterocyclic carbene iron(II) complexes
Authors: Al Thagfi Jameel , Lavoie Gino G.
Published: April 2014

Density functional theory calculations at the B3LYP/DGDZVP and UB3LYP/TZVP levels were performed on 1,3-bis[1-(2,6-dimethylphenylimino)ethyl]imidazolium and on the corresponding imidazol-2-ylidene iron(II) dichloride complex, respectively. The resulting geometrical parameters of the optimized structures were in good agreement with previously reported X-ray structures. The ground state for the high-spin (quintet multiplicity) iron complex is 82.4 kJ/mol lower in energy compared to the low-spin (triplet) configuration, in agreement with magnetic susceptibility measurements. Further calculations were carried out on related benzimidazol-2-ylidene and pyrimidin-2-ylidene ligands and on the corresponding iron complexes to gain insight into their electronic properties and reactivities. The energy of the highest occupied and lowest unoccupied molecular orbitals of all three carbenes suggests that the pyrimidin-2-ylidene and the benzimidazol-2-ylidene are the best σ-donor and best π-acceptor, respectively. Using those results, the metal center in the pyrimidin-2-ylidene iron dichloride complex was predicted to bear the highest electron density. This was supported by the high relative energy of its highest occupied molecular orbital compared to that of the corresponding imidazole-2-ylidene and benzimidazol-2-ylidene iron complexes. The electrostatic potential maps of all three metal complexes furthermore indicated a marked decrease in electron density for the coordinated imine group, supporting a greater reactivity towards nucleophiles.
Synthesis and structure of iron(III) complexes of amine-bis(phenolate) ligands
Authors: Chard Elliott F. , Thompson John R. , Dawe Louise N. , Kozak Christopher M.
Published: April 2014

The synthesis and structures of four new iron(III) amine-bis(phenolate) complexes are reported. Reaction of anhydrous FeCl3 with the diprotonated tridentate ligand isopropyl-N,N-bis(2-methylene-4-t-butyl-6-methylphenol) (H2L1) and NEt3 produces the trigonal bipyramidal iron(III) complex [NEt3H]+ [FeCl2L1]– (1). The reaction of FeBr3 with the sodium or lithium salts, Na2L1 and Li2L2, results in the formation of FeBr2L1H (2) and FeBr2L2H (3), tetrahedral iron(III) complexes possessing two bromide ligands and quaternized ammonium fragments. A trigonal bipyramidal FeIII hydroxido-bridged dimer, [Fe(μ-OH)L2]2 (4), was also isolated during the synthesis of 3. Single-crystal X-ray molecular structures have been determined for complexes 1–4 and H2L2.
Time-dependent drainage of an Eyring film of variable thickness adhering to a vertical plate
Authors: Siddiqui A.M. , Walait A. , Haroon T. , Ansari A.R.
Published: April 2014

In this paper, we investigate the time-dependent drainage of a thin film of Eyring fluid of variable thickness, flowing down a vertical plate. The exact solutions for the velocity distribution, flow rate, mean thickness, average velocity, vorticity vector, and stress are obtained. Graphical results are presented and discussed for various flow variables like the velocity profile and the variable thickness.
Stability analysis of the polytropic solar wind
Authors: Karmakar P.K. , Gohain M. , Deka U.
Published: April 2014

A linear stability analysis of a simple polytropic model for the solar wind dynamics within the framework of a magnetohydrodynamic equilibrium configuration is theoretically proposed. The simplistic analysis is based on the model developed based on the data available from the Advanced Composition Explorer (ACE) spacecraft mission. A unique form of dispersion relation is derived by coupling the adiabatic and polytropic processes in the limit of ideal gas approximation for the solar wind gas in accordance with the standard Fourier technique. Applying usual variable-separation methodology on the dispersion relation, we obtain the linear growth rate of the fluctuations. It is seen that the growth rate is an explicitly nonlinear function of the variable polytropic index (α) and radial position (r) with respect to the considered center of the Sun. Numerical analyses are carried out to understand the physical insight of the growth profiles of the fluctuations. It is shown that the growth is maximized near the solar corona, where α ∼ 1, relative to that observed elsewhere in the entire solar plasma system. The source for this growth may be attributed to the free flow of energy coming from the dynamic equilibrium of the solar plasma itself. As compared with existing model predictions, our results are qualitatively capable of reproducing the average behavior of the solar wind fluctuation and stability behaviors on the astrophysical scales of space and time.
The spinless relativistic Woods–Saxon problem
Authors: Lucha Wolfgang , Schöberl Franz F.
Published: April 2014

Motivated by the observation of a recent renewal of rather strong interest in the description of bound states by (semi)relativistic equations of motion, we revisit, for the example of the Woods–Saxon interactions, the eigenvalue problem posed by the spinless Salpeter equation and recall various elementary knowledge, considerations and techniques that practitioners seeking solutions to this specific reduction of the Bethe–Salpeter equation may find helpful.
External sources in field–antifield formalism
Authors: Batalin Igor A. , Bering Klaus
Published: April 2014

We introduce external sources JA directly into the quantum master action W of the field–antifield formalism instead of the effective action. The external sources JA lead to a set of BRST-invariant functions WA that are in antisymplectic involution. As a byproduct, we encounter quasi-groups with open gauge algebras.
Comment on "Cosmic-ray-driven reaction and greenhouse effect of halogenated molecules: Culprits for atmospheric ozone depletion and global climate change"
Authors: Müller Rolf , Grooß Jens-Uwe
Published: April 2014

Lu's "cosmic-ray-driven electron-induced reaction (CRE) theory" is based on the assumption that the CRE reaction of halogenated molecules (e.g., chlorofluorocarbons (CFCs), HCl, ClONO2) adsorbed or trapped in polar stratospheric clouds in the winter polar stratosphere is the key step in forming photoactive halogen species that are the cause of the springtime ozone hole. This theory has been extended to a warming theory of halogenated molecules for climate change. In this comment, we discuss the chemical and physical foundations of these theories and the conclusions derived from the theories. First, it is unclear whether the loss rates of halogenated molecules induced by dissociative electron attachment (DEA) observed in the laboratory can also be interpreted as atmospheric loss rates, but even if this were the case, the impact of DEA-induced reactions on polar chlorine activation and ozone loss in the stratosphere is limited. Second, we falsify several conclusions that are reported on the basis of the CRE theory: There is no polar ozone loss in darkness, there is no apparent 11-year periodicity in polar total ozone measurements, the age of air in the polar lower stratosphere is much older than 1–2 years, and the reported detection of a pronounced recovery (by about 20–25%) in Antarctic total ozone measurements by the year 2010 is in error. There are also conclusions about the future development of sea ice and global sea level which are fundamentally flawed because Archimedes' principle is neglected. Many elements of the CRE theory are based solely on correlations between certain datasets which are no substitute for providing physical and chemical mechanisms causing a particular behavior noticeable in observations. In summary, the CRE theory cannot be considered as an independent, alternative mechanism for polar stratospheric ozone loss and the conclusions on recent and future surface temperature and global sea level change do not have a physical basis.
Electronic and optical properties of InGaAs/GaAs quantum dots with tunable aspect-ratio
Authors: Lu Pengfei , Zhong Xuxia , Sun Chao , Yu Zhongyuan , Han Lihong , Wang Shumin
Published: April 2014

In this paper, a combined approach of finite element method (FEM) and quadratic programming optimization method is proposed to investigate the nonuniform equilibrium composition profile of InGaAs / GaAs quantum dots (QDs) in the framework of Gibbs energy optimization (GEO). The proposed QDs are varied with aspect ratio from 0.3 to 0.5. The wave functions of electron and heavy hole are predicted by using the k ⋅ p method. The changes of wave functions before and after optimization can be observed by using composition optimization. Both the eigenvalues and transition energy change obviously with the increasing aspect ratio. The linear optical absorption coefficients corresponding to the interband ground state transition are obtained via the density matrix approach and perturbation expansion method. The numerical results reveal that the aspect ratio and composition profile play significant roles in determining the electronic and optical properties.
Unconventional geometric phase gates for two distant atoms trapped in spatially separate cavities
Authors: Zhang Aiping , Zhang Xiuxing , Wang Zhanmin , Tian Shanshan
Published: April 2014

In this paper, we propose a scheme for implementing an unconventional two-qubit geometric phase gate for two distant atoms trapped in cavities connected by an optical fiber. During the gate operation, the atoms are still in the ground states, while the cavity modes and fiber mode are displaced along a circle in the phase space. In this way, the system can acquire different geometric phases conditional upon the atomic states. We find that the operation of the geometric phase gate can be speeded up as the detuning between the cavity field and light fields decreases. Moreover, it is observed that the fidelity for the geometric phase gate is remarkably insensitive to the fluctuation of the detuning parameter. The effects of cavity decay and fiber loss on the gate have also been checked.
A SCALE-SPACE TOGGLE OPERATOR FOR IMAGE TRANSFORMATIONS
Authors: DORINI LEYZA BALDO , LEITE NEUCIMAR JERÔNIMO
Published: April 2014

The analysis of different representation levels has been largely used in several image analysis tasks to handle the multiscale nature of image data, allowing the extraction of specific features that become explicit at each scale. In this work, we explore the scale-space properties of a self-dual toggle operator defined on a scaled morphological framework. These properties conduce to a well-controlled image simplification where its maxima and minima interact at the same time during pixels' transformation, in contrast to other approaches that consider these extrema separately. In such a way, it is possible to identify significant image extrema information to be used in several high level tasks. To assess the robustness of our approach, we carry out tests on images of several classes and subjected to different lighting conditions for various applications, including segmentation and binarization.
Formation of self-assembled nanodomain structures in single crystals of uniaxial ferroelectrics lithium niobate, lithium tantalate and strontium–barium niobate
Authors: Shur V. Ya. , Shikhova V. A. , Zelenovskiy P. S. , Pelegov D. V. , Ivleva L. I. , Dec J.
Published: April 2014

The formation and evolution of the self-assembled nanodomain structures during polarization reversal have been comparatively analyzed in single crystals of various uniaxial ferroelectrics: LiNbO 3 (LN), LiTaO 3 (LT) and Sr x Ba 1-x Nb 2 O 6 (SBN). Several experimental methods have been used for visualization of the micro- and nanodomain patterns. The static domain images have been obtained by optical microscopy and piezoresponse force microscopy. The Raman confocal microscopy allowed us to obtain the domain images in the bulk. The equilibrium slow switching with effective screening resulted in growth of polygon-shaped micro-domains: hexagons in LN, triangles in LT and squares in SBN, which corresponds to crystal symmetry. Switching in nonequilibrium conditions (noneffective screening of depolarization field) brings to appearance of similar nanodomain structures in all studied crystals as a result of different processes: (1) formation of nanodomain ensembles, (2) discrete switching, (3) incomplete merging and (4) spontaneous backswitching.
Erosion in the Chilean Andes between 27°S and 39°S: tectonic, climatic and geomorphic control
Authors: Carretier S. , Tolorza V. , Rodríguez M. P. , Pepin E. , Aguilar G. , Regard V. , Martinod J. , Riquelme R. , Bonnet S. , Brichau S. , Hérail G. , Pinto L. , Farías M. , Charrier R. , Guyot J. L.
Published: April 2014

The effect of mean precipitation rate on erosion is debated. Three hypotheses may explain why the current erosion rate and runoff may be spatially uncorrelated: (1) the topography has reached a steady state for which the erosion rate pattern is determined by the uplift rate pattern; (2) the erosion rate only depends weakly on runoff; or (3) the studied catchments are experiencing different transient adjustments to uplift or to climate variations. In the Chilean Andes, between 27°S and 39°S, the mean annual runoff rates increase southwards from 0.01 to 2.6 m a
−1
but the catchment averaged rates of decadal erosion (suspended sediment) and millennial erosion (
10
Be in river sand) peak at
c.
0.25 mm a
−1
for runoff
c.
0.5 m a
−1
and then decrease while runoff keeps increasing. Erosion rates increase non-linearly with the slope and weakly with the square root of the runoff. However, sediments trapped in the subduction trench suggest a correlation between the current runoff pattern and erosion over millions of years. The third hypothesis above may explain these different erosion rate patterns; the patterns seem consistent with, although not limited to, a model where the relief and erosion rate have first increased and then decreased in response to a period of uplift, at rates controlled by the mean precipitation rate.