bluuebunny/crossref_metadata_2025 huggingface dataset:
Stability and electronic structure of two dimensional Cx(BN)y compound
Authors: Lam Kai-Tak , Lu Yunhao , Feng Yuan Ping , Liang Gengchiau
Published: January 2011

The thermal stability and electronic structures of two dimensional Cx(BN)y compounds are studied using first-principles calculations based on the density functional theory. Although, from total energy calculations, it was well-established that phase-segregated atomic arrangements had the lowest energy, we found that due to the high activation energy required for phase-segregation process, evenly distributed configurations are stable at room temperature. Furthermore, the energy bandgap (EG) of the evenly distributed Cx(BN)y compounds is dependent on the carbon concentration. By controlling the carbon concentration in the compound, the EG of the compound material can be adjusted for electronic applications.
Directional single mode quantum cascade laser emission using second-order metal grating coupler
Authors: Maisons G. , Carras M. , Garcia M. , Simozrag B. , Marcadet X.
Published: January 2011

We report on the design and experimental demonstration of a substrate emitting quantum cascade laser (QCL) with low beam divergence in the two directions. A low-loss, index-coupled, distributed feedback laser is coupled to a monolithic extraction area. Both functions are performed with a top metal grating spatially differentiated for improving the divergence of the QCL in the two directions. Spectrally single-mode InGaAs/AlInAs QCL emitting at a wavelength of 5.65 μm with a low beam divergence, represented by a full width at half maximum of 2.3° and 4°, is demonstrated at room temperature with a threshold current of 2.1 kA/cm2.
Spin torque switching of perpendicular Ta∣CoFeB∣MgO-based magnetic tunnel junctions
Authors: Worledge D. C. , Hu G. , Abraham David W. , Sun J. Z. , Trouilloud P. L. , Nowak J. , Brown S. , Gaidis M. C. , O’Sullivan E. J. , Robertazzi R. P.
Published: January 2011

Spin torque switching is investigated in perpendicular magnetic tunnel junctions using Ta∣CoFeB∣MgO free layers and a synthetic antiferromagnet reference layer. We show that the Ta∣CoFeB interface makes a key contribution to the perpendicular anisotropy. The quasistatic phase diagram for switching under applied field and voltage is reported. Low switching voltages, Vc 50 ns=290 mV are obtained, in the range required for spin torque magnetic random access memory. Switching down to 1 ns is reported, with a rise in switching speed from increased overdrive that is eight times greater than for comparable in-plane devices, consistent with expectations from a single-domain model.
Temperature tunability of photonic crystal fiber filled with Fe3O4 nanoparticle fluid
Authors: Miao Yinping , Liu Bo , Zhang Kailiang , Liu Yan , Zhang Hao
Published: January 2011

Fe 3 O 4 nanoparticles fluid has unique optical properties, which provides versatile possibilities to design state-of-the-art photonic devices. In this paper, by combining Fe3O4 nanoparticles fluid with the photonic crystal fiber (PCF), the spectral characteristics of fluid-filled PCF under different temperatures were experimentally demonstrated. Transmission power and the long wavelength edge of the dip are both found to become highly temperature dependent. The experimental results indicate the slope of this edge is adjustable by changing temperature and there is a linear relationship between transmission power and temperature. This suggests the potential application of this device as an intensity-modulated sensing element or a tunable all-in-fiber gain equalization filter with an adjustable slope.
Extremely low temperature coefficient of resistance in antiperovskite Mn3Ag1−xCuxN
Authors: Takenaka K. , Ozawa A. , Shibayama T. , Kaneko N. , Oe T. , Urano C.
Published: January 2011

Electrical resistivity is systematically investigated in Mn3AgN and related compounds with an antiperovskite structure. Despite its overall metallic character, Mn3AgN features a broad maximum in the temperature-resistivity curve in the paramagnetic state and the temperature coefficient of resistance (TCR) is negative at higher temperatures. The resistivity-peak temperature was tuned to just room temperature by the partial substitution of Cu for Ag, and a TCR as low as 10−6 K−1 was achieved over a wide temperature window including room temperature. These peculiar behaviors are possibly due to collapse of coherent quasiparticle states by strong magnetic scattering.
Enhanced thermoelectric performance in p-type BiSbTe bulk alloy with nanoinclusion of ZnAlO
Authors: Zhang Ting , Zhang Qiushi , Jiang Jun , Xiong Zhen , Chen Jianmin , Zhang Yulong , Li Wei , Xu Gaojie
Published: January 2011

p-type BiSbTe/x wt % ZnAlO (x=0, 0.25, 0.5, 0.75, and 1.0) composites were prepared by zone melting method. A peak thermoelectric figure of merit (ZT) of 1.33 at 370 K was achieved for the sample with x=0.75, about 34% higher than that of BiSbTe at the same temperature, making these composites more attractive for commercial applications. This enhancement of ZT can be mainly ascribed to a remarkable increase of the electrical conductivity and a simultaneous decrease of the lattice thermal conductivity by the introduction of ZnAlO nanopowder.
Are Innovative Regions More Unequal? Evidence from Europe
Authors: Lee Neil
Published: January 2011

Studies of the United States have suggested that the most innovative areas are also the most unequal. There are a number of potential processes that might lead to this. Innovation may raise the return of human capital in ways which can lead to localised inequality. Innovative industries may be subject to greater wage polarisation or offer more erratic returns than other industries. Moreover, the affluent may hire others to work in poorly paid personal service employment nearby. However, while there is some evidence for these processes in the US, whether this applies in the European case is less certain. I use the European Community Household Panel and the Eurostat Regio database to test the link between innovation and wage inequality in a panel of European regions for the period 1996–2001. Two measures of innovation are used: employment in knowledge-based industries and the level of patenting in a region. The results are indicative of a positive link between regional innovation, as measured by patenting, and inequality. In contrast, there is little evidence of a link between knowledge-based industries and inequality, with the exception of a positive relationship between employment in knowledge-intensive financial services and inequality.
Perceiving Affordances for Joint Actions
Authors: Davis Tehran J , Riley Michael A , Shockley Kevin , Cummins-Sebree Sarah
Published: January 2011

Two individuals acting together to achieve a shared goal often have an emergent set of afforded behavioral possibilities that may not easily reduce to either acting alone. In a series of experiments we examined the critical boundaries for transitions in behavior for individuals walking through an aperture alone or alongside another actor as a dyad. Results from experiment 1 indicated that an intrinsically scaled critical boundary for behavioral transitions was different in individuals than in dyads performing a similar task. Experiment 2 demonstrated that observers are perceptually sensitive to the difference in action parameters for the dyad, while still maintaining perceptual sensitivity about the boundaries of action relative to individuals. In experiment 3, we determined that observers' perception of critical action boundaries for individuals and dyads has a similar informational basis (eye-height scaling). In experiment 4, we demonstrated that observers were able to perceive critical action boundaries for other dyads independently of membership. Together, these results suggest that individuals are sensitive to the affordances related to a joint action, and that this process may not entirely reduce to the perception of the affordances for each individual.
Learning New Faces in Typically Developing Children and Children on the Autistic Spectrum
Authors: Wilson C Ellie , Palermo Romina , Brock Jon , Burton A Mike
Published: January 2011

As faces become familiar, recognition becomes easier but the style of processing also changes. Here, twenty-one typically developing (TD) children and twenty-one children with autism spectrum disorder (ASD) were familiarised with 6 identities over 3 days. Next, they completed a 4-alternative forced-choice matching test in which targets were the 6 familiarised faces and 6 unfamiliar faces. The TD group showed a significant advantage for familiarised faces when matching whole faces and both internal and external facial regions. The ASD group showed similar familiarisation effects for whole and external faces, but not for internal regions. The ASD group was also impaired at matching eyes and mouths of familiarised faces. Results suggest the process of acquiring familiarity with faces differs from ASD and TD children.
The paradoxes of Paul Robert Magocsi: the case for Rusyns and the logical necessity of Ukrainians
Authors: Motyl Alexander J.
Published: January 2011

How is it possible for a Rusyn nation-builder to have contributed to the historiography of Ukraine to such a significant degree that one might suspect that Paul Robert Magocsi is really a Ukrainian nation-builder? Like all social-science puzzles, this one dissolves upon closer inspection. Magocsi resembles a Ukrainian nation-builder – or perhaps even is a Ukrainian nation-builder malgré soi – precisely because he is a Rusyn nation-builder. That is so because all nation-builders are always builders of at least two nations, their own and the others.
Nation-building ancient Macedonian style: the origins and the effects of the so-called antiquization in Macedonia
Authors: Vangeli Anastas
Published: January 2011

The background of the contemporary Macedonian “antiquization” can be found in the nineteenth century and the myth of ancient descent among Orthodox Slavic speakers in Macedonia, adopted partially due to Greek cultural inputs. The idea of Ancient Macedonian nationhood has also been included in the national mythology during the Yugoslav era. An additional factor for its preservation has been the influence of the Macedonian Diaspora. After independence, attempts to use myth of ancient descent had to be abandoned due to political pressure by Greece. Contemporary antiquization on the other hand, has been revived as an efficient tool for political mobilization. It is manifested as a belated invention and mass-production of tradition, carried out through the creation of new ceremonies, interventions in the public space and dissemination of mythological and metaphysical narratives on the origin of the nation. There have also been attempts to scientifically rationalize claims to ancient nationhood. On the political level, the process of antiquization reinforced the political primacy of its promoters, the ruling Internal Macedonian Revolutionary Organization – Democratic Party for Macedonian National Unity (VMRO-DPMNE), but had a negative impact on the interethnic relations and the international position of the country.
The changing face of the Other in Romanian films
Authors: Andreescu Florentina
Published: January 2011

This article focuses on how the Other is represented and understood in films produced in Romania during periods of radical political, social and economic change. Specifically it addresses films produced during the years of communism and the planned economy, during the transition to democracy and to capitalism, as well as films produced during the period of democracy, capitalism and membership in the European Union. The research acknowledges two main aspects: the changing face of the Other over time (the socialist state, the foreign investors, the West, etc.) and the consistency of the fantasy structure. More specifically, the relationship between self and the Other generally follows a strict masochist fantasy script in which the Other has the power to constrain freedom, to inflict pain, and to function as an essential element through which pleasure is understood and experienced. The research proposes an understanding of this structure of fantasy, reflected in film through the existence of a national psyche written by the main myths and stories embraced by the society in discussion. This structure of fantasy hails and constructs a certain subject that has a basic masochistic psychic structure.
Concluding observations on the symposium
Authors: Magocsi Paul Robert
Published: January 2011

Generosity is the thought that comes to mind after hearing and later reading the five studies first presented at a symposium in Toronto (2 October 2008) and published here in this issue ofNationalities Papers.My colleagues, who span the disciplines of history, literary criticism, and political science, have been generous with the time they spent in composing their essays and then traveling to Toronto to deliver them in person, and they have been particularly generous in conveying a spirit of constructive criticism and self-reflection that represent the best aspects of our common intellectual enterprise. To each of you – George G. Grabowicz, Taras Kuzio (who initiated this symposium), Serhii Plokhy, Alexender J. Motyl, and Dominique Arel – I express my deep appreciation for your generosity of mind and spirit.
Not such a ‘sui generis’ case after all: assessing the ICJ opinion on Kosovo
Authors: Ker-Lindsay James
Published: January 2011

For 60 years, the international community has limited the right of territories to gain independence without the permission of the “parent state.” Such limits were, however, challenged when Kosovo unilaterally declared independence from Serbia, in February 2008. As a result, Belgrade referred the matter to the International Court of Justice (ICJ). On 22 July 2010, it came back with its long-awaited decision. Taking a narrow view of the question, the majority argued that, in general, declarations of independence, as mere statements, do not violate international law unless stated otherwise by the Security Council. Thus, Kosovo's declaration of independence cannot be considered as being wholly “unique” – as those states that supported its statehood have claimed. On the key questions of whether Kosovo's secession is legal, or if it is even a state, they chose to avoid controversy. On these points, the international community is no clearer now than it was before the case.
“The Magocsi Problem” (Problema Magochoho): a preliminary deconstruction and contextualization
Authors: Grabowicz George G.
Published: January 2011

An academic gathering – be it a symposium, a conference, or a round-table – to examine the work of a fellow scholar is invariably timely. At the very least it presupposes a consensus on the basic significance of the subject being addressed and a collective decision to address it. As a launch of a new book (in Ukraine a phenomenon known as prezentatsiia), it provides the welcome opportunity to discuss a new contribution and with that to fill in and redraw our map of the field. If more than one work or project is involved, it provides a still greater opportunity, and indeed poses a scholarly obligation, to see the larger picture and to engage in stocktaking and rethinking. By contextualizing, problematizing, and where need be, deconstructing, we recalibrate our understanding and thus revive the field and our commitment to it. Clearly, the process of laudatio, of paying homage to achievements spanning a whole career, also contributes to this.
Genealogy, history, nation
Authors: Light Nathan
Published: January 2011

This article uses Central Asian examples to challenge theories of ethnic nationalism that locate its origins in intellectual activism (Hroch), state modernization processes (Gellner), or the rise of mass media (Anderson). Modern Uyghur cultural politics and traditional Central Asian dynastic genealogies reveal related processes used in constructing modern nationalist symbols and pre-modern ideologies of descent. Modern territorial states with ideals of social unification and bureaucratic organization rely upon nationalist discourses to elaborate and rework cultural forms into evidence for the ethnic nation. The state links citizens to institutions through nationalist content used in political discourse, schooling, and public performances. Because such content is presented as authentic but used instrumentally, its contingency and fabrication have to be concealed from view: the culturally intimate spaces of bureaucratic production of culture and narratives are separated from public performances. The creation of genealogies used to legitimate pre-modern states are similar: compositional processes and goals are kept offstage, and little is disclosed in the public historical narratives and performances.
Was the emergence of Russian national identity merely a historical accident?
Authors: Luks Leonid
Published: January 2011

David Brandenberger provides, in his recentNationalities Paperdiscussion paper “Stalin's populism and the accidental creation of Russian national identity” an interesting and plausible argument. However, his article contains several, to my view, controversial and unconvincing assumptions which is why I would like to add the below critical remarks to those already made by David R. Marples and Andreas Umland.
Sean Munro: Revealing the Golgi's true identity
Authors: Short Ben
Published: January 2011

Munro studies how proteins localize within the secretory pathway.
Dynamin2- and endothelial nitric oxide synthase–regulated invasion of bladder epithelial cells by uropathogenicEscherichia coli
Authors: Wang Zhimin , Humphrey Ceba , Frilot Nicole , Wang Gaofeng , Nie Zhongzhen , Moniri Nader H. , Daaka Yehia
Published: January 2011

Invasion of bladder epithelial cells by uropathogenic Escherichia coli (UPEC) contributes to antibiotic-resistant and recurrent urinary tract infections (UTIs), but this process is incompletely understood. In this paper, we provide evidence that the large guanosine triphosphatase dynamin2 and its partner, endothelial nitric oxide (NO) synthase (NOS [eNOS]), mediate bacterial entry. Overexpression of dynamin2 or treatment with the NO donor S-nitrosothiols increases, whereas targeted reduction of endogenous dynamin2 or eNOS expression with ribonucleic acid interference impairs, bacterial invasion. Exposure of mouse bladder to small molecule NOS inhibitors abrogates infection of the uroepithelium by E. coli, and, concordantly, bacteria more efficiently invade uroepithelia isolated from wild-type compared with eNOS−/− mice. E. coli internalization promotes rapid phosphorylation of host cell eNOS and NO generation, and dynamin2 S-nitrosylation, a posttranslational modification required for the bacterial entry, also increases during E. coli invasion. These findings suggest that UPEC escape urinary flushing and immune cell surveillance by means of eNOS-dependent dynamin2 S-nitrosylation and invasion of host cells to cause recurrent UTIs.
Homeostatic levels of SRC-2 and SRC-3 promote early human adipogenesis
Authors: Hartig Sean M. , He Bin , Long Weiwen , Buehrer Benjamin M. , Mancini Michael A.
Published: January 2011

The related coactivators SRC-2 and SRC-3 interact with peroxisome proliferator activated receptor γ (PPARγ) to coordinate transcriptional circuits to promote adipogenesis. To identify potential coactivator redundancy during human adipogenesis at single cell resolution, we used high content analysis to quantify links between PPARγ, SRC-2, SRC-3, and lipogenesis. Because we detected robust increases and significant cell–cell heterogeneity in PPARγ and lipogenesis, without changes in SRC-2 or SRC-3, we hypothesized that permissive coregulator levels comprise a necessary adipogenic equilibrium. We probed this equilibrium by down-regulating SRC-2 and SRC-3 while simultaneously quantifying PPARγ. Individual or joint knockdown equally inhibits lipid accumulation by preventing lipogenic gene engagement, without affecting PPARγ protein levels. Supporting dominant, pro-adipogenic roles for SRC-2 and SRC-3, SRC-1 knockdown does not affect adipogenesis. SRC-2 and SRC-3 knockdown increases the proportion of cells in a PPARγhi/lipidlo state while increasing phospho-PPARγ–S114, an inhibitor of PPARγ transcriptional activity and adipogenesis. Together, we demonstrate that SRC-2 and SRC-3 concomitantly promote human adipocyte differentiation by attenuating phospho-PPARγ–S114 and modulating PPARγ cellular heterogeneity.
Making heads or tails of phospholipids in mitochondria
Authors: Osman Christof , Voelker Dennis R. , Langer Thomas
Published: January 2011

Mitochondria are dynamic organelles whose functional integrity requires a coordinated supply of proteins and phospholipids. Defined functions of specific phospholipids, like the mitochondrial signature lipid cardiolipin, are emerging in diverse processes, ranging from protein biogenesis and energy production to membrane fusion and apoptosis. The accumulation of phospholipids within mitochondria depends on interorganellar lipid transport between the endoplasmic reticulum (ER) and mitochondria as well as intramitochondrial lipid trafficking. The discovery of proteins that regulate mitochondrial membrane lipid composition and of a multiprotein complex tethering ER to mitochondrial membranes has unveiled novel mechanisms of mitochondrial membrane biogenesis.
BMP promotes motility and represses growth of smooth muscle cells by activation of tandem Wnt pathways
Authors: de Jesus Perez Vinicio A. , Ali Ziad , Alastalo Tero-Pekka , Ikeno Fumiaki , Sawada Hirofumi , Lai Ying-Ju , Kleisli Thomas , Spiekerkoetter Edda , Qu Xiumei , Rubinos Laura H. , Ashley Euan , Amieva Manuel , Dedhar Shoukat , Rabinovitch Marlene
Published: January 2011

We present a novel cell-signaling paradigm in which bone morphogenetic protein 2 (BMP-2) consecutively and interdependently activates the wingless (Wnt)–β-catenin (βC) and Wnt–planar cell polarity (PCP) signaling pathways to facilitate vascular smooth muscle motility while simultaneously suppressing growth. We show that BMP-2, in a phospho-Akt–dependent manner, induces βC transcriptional activity to produce fibronectin, which then activates integrin-linked kinase 1 (ILK-1) via α4-integrins. ILK-1 then induces the Wnt–PCP pathway by binding a proline-rich motif in disheveled (Dvl) and consequently activating RhoA-Rac1–mediated motility. Transfection of a Dvl mutant that binds βC without activating RhoA-Rac1 not only prevents BMP-2–mediated vascular smooth muscle cell motility but promotes proliferation in association with persistent βC activity. Interfering with the Dvl-dependent Wnt–PCP activation in a murine stented aortic graft injury model promotes extensive neointima formation, as shown by optical coherence tomography and histopathology. We speculate that, in response to injury, factors that subvert BMP-2–mediated tandem activation of Wnt–βC and Wnt–PCP pathways contribute to obliterative vascular disease in both the systemic and pulmonary circulations.
p62 targeting to the autophagosome formation site requires self-oligomerization but not LC3 binding
Authors: Itakura Eisuke , Mizushima Noboru
Published: January 2011

Autophagy is an intracellular degradation process by which cytoplasmic contents are degraded in the lysosome. In addition to nonselective engulfment of cytoplasmic materials, the autophagosomal membrane can selectively recognize specific proteins and organelles. It is generally believed that the major selective substrate (or cargo receptor) p62 is recruited to the autophagosomal membrane through interaction with LC3. In this study, we analyzed loading of p62 and its related protein NBR1 and found that they localize to the endoplasmic reticulum (ER)–associated autophagosome formation site independently of LC3 localization to membranes. p62 colocalizes with upstream autophagy factors such as ULK1 and VMP1 even when autophagosome formation is blocked by wortmannin or FIP200 knockout. Self-oligomerization of p62 is essential for its localization to the autophagosome formation site. These results suggest that p62 localizes to the autophagosome formation site on the ER, where autophagosomes are nucleated. This process is similar to the yeast cytoplasm to vacuole targeting pathway.
SET8 is degraded via PCNA-coupled CRL4(CDT2) ubiquitylation in S phase and after UV irradiation
Authors: Jørgensen Stine , Eskildsen Morten , Fugger Kasper , Hansen Lisbeth , Yoo Larsen Marie Sofie , Kousholt Arne Nedergaard , Syljuåsen Randi G. , Trelle Morten Beck , Nørregaard Jensen Ole , Helin Kristian , Sørensen Claus Storgaard
Published: January 2011

The eukaryotic cell cycle is regulated by multiple ubiquitin-mediated events, such as the timely destruction of cyclins and replication licensing factors. The histone H4 methyltransferase SET8 (Pr-Set7) is required for chromosome compaction in mitosis and for maintenance of genome integrity. In this study, we show that SET8 is targeted for degradation during S phase by the CRL4(CDT2) ubiquitin ligase in a proliferating cell nuclear antigen (PCNA)–dependent manner. SET8 degradation requires a conserved degron responsible for its interaction with PCNA and recruitment to chromatin where ubiquitylation occurs. Efficient degradation of SET8 at the onset of S phase is required for the regulation of chromatin compaction status and cell cycle progression. Moreover, the turnover of SET8 is accelerated after ultraviolet irradiation dependent on the CRL4(CDT2) ubiquitin ligase and PCNA. Removal of SET8 supports the modulation of chromatin structure after DNA damage. These results demonstrate a novel regulatory mechanism, linking for the first time the ubiquitin–proteasome system with rapid degradation of a histone methyltransferase to control cell proliferation.
Singular reduction of Dirac structures
Authors: Jotz M. , Ratiu T. , Śniatycki J.
Published: January 2011

The regular reduction of a Dirac manifold acted upon freely and properly by a Lie group is generalized to a nonfree action. For this, several facts about

G
G

-invariant vector fields and one-forms are shown.
In Situ Production of Prebiotic AXOS by Hyperthermophilic Xylanase B from Thermotoga maritima in High‐Quality Bread
Authors: Dornez Emmie , Verjans Priscilla , Broekaert Willem F. , Cappuyns Astrid M. , Van Impe Jan F. , Arnaut Filip , Delcour Jan A. , Courtin Christophe M.
Published: January 2011

In situ enrichment of bread with arabinoxylan‐oligosaccharides (AXOS) through enzymic degradation of wheat flour arabinoxylan (AX) by the hyperthermophilic xylanase B from Thermotoga maritima (rXTMB) was studied. The xylanolytic activity of rXTMB during breadmaking was essentially restricted to the baking phase. This prevented problems with dough processability and bread quality that generally are associated with thorough hydrolysis of the flour AX during dough mixing and fermentation. rXTMB action did not affect loaf volume. Bread with a dry matter AXOS content of 1.5% was obtained. Further increase in bread AXOS levels was achieved by combining rXTMB with xylanases from Pseudoalteromonas haloplanktis or Bacillus subtilis. Remarkably, such a combination synergistically increased the specific bread loaf volume. Assuming an average daily consumption of 180 g of fresh bread, the bread AXOS levels suffice to provide a substantial part of the AXOS intake leading to desired physiological effects in humans.
Vitis californicaandVitis californica×Vitis viniferaHybrids are Hosts forGrapevine leafroll-associated virus-2and-3andGrapevine virus AandB
Authors: Klaassen V. A. , Sim S. T. , Dangl G. S. , Osman F. , Rwahnih M. Al , Rowhani A. , Golino D. A.
Published: January 2011

Vitis and non-Vitis spp. surrounding nine Napa Valley vineyards were surveyed for Grapevine leafroll-associated virus (GLRaV)-1 to -5 and -9, Grapevine virus A (GVA), Grapevine virus B (GVB), and Grapevine virus D (GVD). Vitis spp. from three riparian areas not adjacent to vineyards were also included. DNA fingerprinting and probability analyses indicated that the Vitis samples consisted primarily of Vitis californica followed by V. californica × V. vinifera hybrids. Single and mixed infections of GLRaV-2, -3, GVA, or GVB were detected by conventional or quantitative reverse-transcription polymerase chain reaction in 6 of the 66 V. californica and 11 of the 19 V. californica × V. vinifera hybrids. GLRaV-1, -4, -5, -9, and GVD were not detected. Phylogenetic analysis of GLRaV-2 and -3 partial coat protein gene nucleotide sequences indicated that the isolates from V. californica and V. californica × V. vinifera hybrids were closely related to isolates from V. vinifera.
Real-Time PCR Detection and Discrimination of the Southern and Common Corn Rust Pathogens Puccinia polysora and Puccinia sorghi
Authors: Crouch Jo Anne , Szabo Les J.
Published: January 2011

Over the past several years, southern corn rust (SCR) outbreaks caused by the fungus Puccinia polysora have become increasingly problematic for corn growers in the United States. SCR is currently diagnosed through the visual examination of disease symptoms and pathogen morphology, including pigmentation, size, shape, and location of fruiting structures. However, these characteristics are similar to those produced by the common corn rust fungus P. sorghi, confounding accurate visual diagnosis of SCR. Here we report the development of a real-time polymerase chain reaction assay that discriminates between P. polysora and P. sorghi. Sequences of the rDNA internal transcribed spacer region were determined for P. polysora and P. sorghi. 5-Carboxyfluorescein fluorophore-labeled hydrolysis probes that differed at 14 nucleotide positions between the species were developed from these data and used to screen DNA extracted directly from rust-infected corn leaves. Species-specific, reproducible identifications of the pathogens were made from as little as 50 pg of DNA within 30 min, and were reliably performed from both recent collections and herbarium specimens. This assay will be useful for rapid and accurate diagnosis of SCR, and could serve as a tool to monitor the distribution and incidence of the disease in the United States.
Phenological and Phytochemical Changes Correlate with Differential Interactions ofVerticillium dahliaewith Broccoli and Cauliflower
Authors: Njoroge S. M. C. , Vallad G. E. , Park S.-Y. , Kang S. , Koike S. T. , Bolda M. , Burman P. , Polonik W. , Subbarao K. V.
Published: January 2011

Cauliflower (Brassica oleracea var. botrytis subvar. cauliflora) is susceptible to wilt caused by Verticillium dahliae but broccoli (B. oleracea var. italica subvar. cyamosa) is not. Infection of broccoli and cauliflower by a green fluorescent protein-expressing isolate of V. dahliae was examined using epifluorescence and confocal laser-scanning microscopy to follow infection and colonization in relation to plant phenology. Plant glucosinolate, phenolic, and lignin contents were also assayed at 0, 4, 14, and 28 days postinoculation. V. dahliae consistently infected and colonized the vascular tissues of all cauliflower plants regardless of age at inoculation, with the pathogen ultimately appearing in the developing seed; however, colonization decreased with plant age. In broccoli, V. dahliae infected and colonized root and stem xylem tissues of plants inoculated at 1, 2, or 3 weeks postemergence. However, V. dahliae colonized only the root xylem and the epidermal and cortical tissues of broccoli plants inoculated at 4, 5, and 6 weeks postemergence. The frequency of reisolation of V. dahliae from the stems (4 to 22%) and roots (10 to 40%) of mature broccoli plants was lower than for cauliflower stems (25 to 64%) and roots (31 to 71%). The mean level of aliphatic glucosinolates in broccoli roots was 6.18 times higher than in the shoots and did not vary with age, whereas it was 3.65 times higher in cauliflower shoots than in the roots and there was a proportional increase with age. Indole glucosinolate content was identical in both cauliflower and broccoli, and both indole and aromatic glucosinolates did not vary with plant age in either crop. Qualitative differences in characterized glucosinolates were observed between broccoli and cauliflower but no differences were observed between inoculated and noninoculated plants for either broccoli or cauliflower. However, the phenolic and lignin contents were significantly higher in broccoli following inoculation than in noninoculated broccoli or inoculated cauliflower plants. The increased resistance of broccoli to V. dahliae infection was related to the increase in phenolic and lignin contents. Significant differential accumulation of glucosinolates associated with plant phenology may also contribute to the resistant and susceptible reactions of broccoli and cauliflower, respectively, against V. dahliae.
Discovery of extra-terrestrial life: assessment by scales of its importance and associated risks
Authors: Almár Iván , Race Margaret S.
Published: January 2011

The Rio Scale accepted by the SETI Committee of the International Academy of Astronautics in 2002 is intended for use in evaluating the impact on society of any announcement regarding the discovery of evidence of extra-terrestrial (ET)
intelligence.
The Rio Scale is mathematically defined using three parameters (class of phenomenon, type of discovery and distance) and a
δ
factor, the assumed credibility of a claim. This paper proposes a new scale applicable to announcements alleging evidence of
ET life within or outside our Solar System
. The London Scale for astrobiology has mathematical structure and logic similar to the Rio Scale, and uses four parameters (life form, nature of phenomenon, type of discovery and distance) as well as a credibility factor
δ
to calculate a London Scale index (LSI) with values ranging from 0 to 10. The level of risk or biohazard associated with a purported discovery is evaluated independently of the LSI value and may be ranked in four categories. The combined information is intended to provide a scalar assessment of the scientific importance, validity and potential risks associated with putative evidence of ET life discovered on Earth, on nearby bodies in the Solar System or in our Galaxy.
The evolution of organic matter in space
Authors: Ehrenfreund Pascale , Spaans Marco , Holm Nils G.
Published: January 2011

Carbon, and molecules made from it, have already been observed in the early Universe. During cosmic time, many galaxies undergo intense periods of star formation, during which heavy elements like carbon, oxygen, nitrogen, silicon and iron are produced. Also, many complex molecules, from carbon monoxide to polycyclic aromatic hydrocarbons, are detected in these systems, like they are for our own Galaxy. Interstellar molecular clouds and circumstellar envelopes are factories of complex molecular synthesis. A surprisingly high number of molecules that are used in contemporary biochemistry on the Earth are found in the interstellar medium, planetary atmospheres and surfaces, comets, asteroids and meteorites and interplanetary dust particles. Large quantities of extra-terrestrial material were delivered via comets and asteroids to young planetary surfaces during the heavy bombardment phase. Monitoring the formation and evolution of organic matter in space is crucial in order to determine the prebiotic reservoirs available to the early Earth. It is equally important to reveal abiotic routes to prebiotic molecules in the Earth environments. Materials from both carbon sources (extra-terrestrial and endogenous) may have contributed to biochemical pathways on the Earth leading to life’s origin. The research avenues discussed also guide us to extend our knowledge to other habitable worlds.
The implications of the discovery of extra-terrestrial life for religion
Authors: Peters Ted
Published: January 2011

This paper asks about the future of religion: (i) Will confirmation of extra-terrestrial intelligence (ETI) cause terrestrial religion to collapse? ‘No’ is the answer based upon a summary of the ‘Peters ETI Religious Crisis Survey’. Then the paper examines four specific challenges to traditional doctrinal belief likely to be raised at the detection of ETI: (ii) What is the scope of God’s creation? (iii) What can we expect regarding the moral character of ETI? (iv) Is one earthly incarnation in Jesus Christ enough for the entire cosmos, or should we expect multiple incarnations on multiple planets? (v) Will contact with more advanced ETI diminish human dignity? More than probable contact with extra-terrestrial intelligence will expand the Bible’s vision so that all of creation—including the 13.7 billion year history of the universe replete with all of God’s creatures—will be seen as the gift of a loving and gracious God.
Searching for a shadow biosphere on Earth as a test of the ‘cosmic imperative’
Authors: Davies P. C. W.
Published: January 2011

Estimates for the number of communicating civilizations in the galaxy, based on the so-called Drake equation, are meaningless without a plausible estimate for the probability that life will emerge on an Earth-like planet. In the absence of a theory of the origin of life, that number can be anywhere from 0 to 1. Distinguished scientists have been known to argue that life on Earth is a freak accident, unique in the observable universe and, conversely, that life is almost bound to arise in the course of time, given Earth-like conditions. De Duve, adopting the latter position, coined the phrase that ‘life is a cosmic imperative’. De Duve’s position would be immediately verified if we were to discover a second sample of life that we could be sure arose from scratch independently of known life. Given the current absence of evidence for life beyond Earth, the best way to test the hypothesis of the cosmic imperative is to see whether terrestrial life began more than once. If it did, it is possible that descendants of a second genesis might be extant, forming a sort of ‘shadow biosphere’ existing alongside, or perhaps interpenetrating, the known biosphere. I outline a strategy to detect the existence of such a shadow biosphere.
Astrobiology, space and the future age of discovery
Authors: Blumberg Baruch S.
Published: January 2011

Astrobiology is the study of the origins, evolution, distribution and future of life in the Universe, and specifically seeks to understand the origin of life and to test the hypothesis that life exists elsewhere than on Earth. There is a general mathematics, physics and chemistry; that is, scientific laws that obtain on Earth also do so elsewhere. Is there a general biology? Is the Universe life-rich or is Earth an isolated island of biology? Exploration in the Age of Enlightenment required the collection of data in unexplored regions and the use of induction and empiricism to derive models and natural laws. The current search for extra-terrestrial life has a similar goal, but with a much greater amount of data and with computers to help with management, correlations, pattern recognition and analysis. There are 60 active space missions, many of them aiding in the search for life. There is not a universally accepted definition of life, but there are a series of characteristics that can aid in the identification of life elsewhere. The study of locations on Earth with similarities to early Mars and other space objects could provide a model that can be used in the search for extra-terrestrial life.
Exoplanets: the quest for Earth twins
Authors: Mayor Michel , Udry Stephane , Pepe Francesco , Lovis Christophe
Published: January 2011

Today, more than 400 extra-solar planets have been discovered. They provide strong constraints on the structure and formation mechanisms of planetary systems. Despite this huge amount of data, we still have little information concerning the constraints for extra-terrestrial life, i.e. the frequency of Earth twins in the habitable zone and the distribution of their orbital eccentricities. On the other hand, these latter questions strongly excite general interest and trigger future searches for life in the Universe. The status of the extra-solar planets field—in particular with respect to very-low-mass planets—will be discussed and an outlook on the search for Earth twins will be given in this paper.
The search for life in our Solar System and the implications for science and society
Authors: McKay Christopher P.
Published: January 2011

The search for another type of life in the Solar System addresses the fundamental question of life in the Universe. To determine if life forms we discover represent a second genesis, we must find biological material that would allow us to compare that life to the Earth’s phylogenetic tree of life. An organism would be alien if, and only if, it did not link to our tree of life. In our Solar System, the worlds of interest for a search for life are Mars, Europa, Enceladus and, for biochemistry based on a liquid other than water, Titan. If we find evidence for a second genesis of life, we will certainly learn from the comparative study of the biochemistry, organismal biology and ecology of the alien life. The discovery of alien life, if alive or revivable, will pose fundamentally new questions in environmental ethics. We should plan our exploration strategy such that we conduct biologically reversible exploration. In the long term we would do well, ethically and scientifically, to strive to support any alien life discovered as part of an overall commitment to enhancing the richness and diversity of life in the Universe.
The search for extra-terrestrial intelligence
Authors: Drake Frank
Published: January 2011

Modern history of the search for extra-terrestrial intelligence is reviewed. The history of radio searches is discussed, as well as the major advances that have occurred in radio searches and prospects for new instruments and search strategies. Recent recognition that searches for optical and infrared signals make sense, and the reasons for this are described, as well as the equipment and special detection methods used in optical searches. The long-range future of the search for extra-terrestrial intelligence (SETI) is discussed in the context of the history of rapid change, on the cosmic and even the human time scale, of the paradigms guiding SETI searches. This suggests that SETI searches be conducted with a very open mind.
Supra-Earth affairs
Authors: Othman Mazlan
Published: January 2011

The United Nations briefly considered the issue of extra-terrestrial intelligence at the 32nd session of the General Assembly in 1977. As a result, the Office of Outer Space Affairs was tasked to prepare a document on issues related to ‘messages to extra-terrestrial civilizations’, but this area has not been followed through in more recent times. This discussion paper describes the United Nations’ activities in the field of near-Earth objects in some detail, and suggests that this might be used as a model of how Member States could proceed with dealing with this issue in case the existence of extra-terrestrial life/intelligence is established.
Life as a cosmic imperative?
Authors: de Duve Christian
Published: January 2011

The origin of life on Earth may be divided into two stages separated by the first appearance of replicable molecules, most probably of RNA. The first stage depended exclusively on chemistry. The second stage likewise involved chemistry, but with the additional participation of selection, a necessary concomitant of inevitable replication accidents. Consideration of these two processes suggests that the origin of life may have been close to obligatory under the physical–chemical conditions that prevailed at the site of its birth. Thus, an extrasolar planet in which those conditions were replicated appears as a probable site for the appearance of extra-terrestrial life.
Comparison of iterative desmearing procedures for one-dimensional small-angle scattering data
Authors: Vad Thomas , Sager Wiebke F. C.
Published: January 2011

Two simple iterative desmearing procedures – the Lake algorithm and the Van Cittert method – have been investigated by introducing different convergence criteria using both synthetic and experimental small-angle neutron scattering data. Implementing appropriate convergence criteria resulted in stable and reliable solutions in correcting resolution errors originating from instrumental smearing,i.e.finite collimation and polychromaticity of the incident beam. Deviations at small momentum transfer for concentrated ensembles of spheres encountered in earlier studies are not observed. Amplification of statistical errors can be reduced by applying a noise filter after desmearing. In most cases investigated, the modified Lake algorithm yields better results with a significantly smaller number of iterations and is, therefore, suitable for automated desmearing of large numbers of data sets.
Determining the energy-dependent X-ray flux variation of a synchrotron beamline using Laue diffraction patterns
Authors: Dejoie Catherine , Kunz Martin , Tamura Nobumichi , Bousige Colin , Chen Kai , Teat Simon , Beavers Christine , Baerlocher Christian
Published: January 2011

Although the spectrum originating from a superconducting bending magnet is quasi-continuous, it shows important intensity variations through its spectral range. A method to determine the incident energy-dependent flux variation based on the comparison between observed intensities and the calculated intensities of a well known structure (calcite) is presented here. It is found that the measured flux is highly sensitive to the use of correct Debye–Waller factors for the atoms of the standard crystal. By using the measured flux curve, it was possible to unambiguously index the Laue diffraction pattern of a trigonal crystal structure in its hexagonal setting. This is a crucial but difficult first step for the determination of strain and stress in materials with this symmetry, such as quartz, Mg, Ti, Znetc.
A multicomponent calibration approach to the microabsorption problem involving inorganic mixtures
Authors: Guo Liangfeng , Tjahjono Martin , Schreyer Martin , Garland Marc
Published: January 2011

Microabsorption may present a serious obstacle to performing accurate quantitative phase analysis by the Rietveld method for samples that contain phases with high X-ray absorption contrast. In this study, a multicomponent calibration approach is introduced to reduce the systematic bias that is not accounted for in conventional Rietveld analysis. In order to demonstrate this approach, six ternary inorganic mixtures containing components with diverse mass absorption coefficients were prepared. Two of the six mixtures were chosen as a calibration set to obtain the corresponding calibration parameters. These parameters were used to predict accurately the compositions of the remaining mixtures. Additionally, several other issues concerning sample preparation, the choice of the calibration set and the inclusion of complimentary techniques to determine the calibration parameters are addressed. The present approach offers practical advantages over the frequently used Brindley method, since it does not require any additional information concerning particle size and morphology.
Development of ultra-small-angle X-ray scattering–X-ray photon correlation spectroscopy
Authors: Zhang F. , Allen A. J. , Levine L. E. , Ilavsky J. , Long G. G. , Sandy A. R.
Published: January 2011

This paper describes the development of ultra-small-angle X-ray scattering–X-ray photon correlation spectroscopy (USAXS–XPCS). This technique takes advantage of Bonse–Hart crystal optics and is capable of probing the long-time-scale equilibrium and non-equilibrium dynamics of optically opaque materials with prominent features in a scattering vector range between those of dynamic light scattering and conventional XPCS. Instrumental parameters for optimal coherent-scattering operation are described. Two examples are offered to illustrate the applicability and capability of USAXS–XPCS. The first example concerns the equilibrium dynamics of colloidal dispersions of polystyrene microspheres in glycerol at 10, 15 and 20% volume concentrations. The temporal intensity autocorrelation analysis shows that the relaxation time of the microspheres decays monotonically as the scattering vector increases. The second example concerns the non-equilibrium dynamics of a polymer nanocomposite, for which it is demonstrated that USAXS–XPCS can reveal incipient dynamical changes not observable by other techniques.