bluuebunny/crossref_metadata_2025 huggingface dataset:
A NEIGHBOURHOOD CONDITION FOR GRAPHS TO BE FRACTIONAL (k, m)-DELETED GRAPHS
Authors: ZHOU SIZHONG
Published: July 2009

Let G be a connected graph of order n, and let k ≥ 2 and m ≥ 0 be two integers. In this paper, we show that G is a fractional (k, m)-deleted graph if $\delta(G)\,{\geq}\, k+m+\frac{(m+1)^{2}-1}{4k}$, $n\,{\geq}\, 9k-1-4\sqrt{2(k-1)^{2}+2}+2(2k+1)m$ and $|N_G(x)\cup N_G(y)|\,{\geq}\,\frac{1}{2}(n+k-2)$ for each pair of non-adjacent vertices x, y of G. This result is an extension of the previous result of Zhou [11].
“Sweet Home”: Audre Lorde's Zami and the legacies of American Writing
Authors: PEARL MONICA B.
Published: July 2009

Although Audre Lorde calls the narrative of her life Zami: A New Spelling of My Name a “biomythography,” suggesting that the life of an African American lesbian cannot be told in any previously available generic forms of life-writing or self-expression, Zami actually derives from two extant American literary traditions – the African American slave narrative and the lesbian coming out story – rendering it, after all, not a marginal text, but rather a text that falls obviously and firmly in a tradition of American literature. Both traditions turn siginificantly on the trope of “home,” of finding a home where one belongs. In finding the “home” that she is seeking not, ultimately, geographically, but, rather, generically – in the very text she is writing – Lorde's life story also ends up signifying the similarity of these two ostensibly disparate forms: the slave narrative and the coming out story, suggesting a common narrative trajectory of marginal American identities in the tradition of American life-writing.
Paediatric eosinophilic oesophagitis presenting to the otolaryngologist
Authors: Harris R , Mitton S , Chong S , Daya H
Published: July 2009

Introduction:

The prevalence of eosinophilic oesophagitis is increasing. A Pubmed search for ‘eosinophilic oesophagitis’ and ‘eosinophilic esophagitis’ yielded 345 publications since 1976. Only seven were in otolaryngology journals.1–7Patients typically present with dysphagia, vomiting, dyspepsia or food impaction and are therefore usually referred to a paediatric gastroenterologist; otolaryngologists are not usually involved in management. A missed diagnosis may result in oesophageal stricture.

Methods:

Two patients, aged two and four years, were referred to the paediatric otolaryngology department with intermittent upper oesophageal food impaction. A paediatric gastroenterologist was involved in the investigation. Histological examination of oesophageal biopsies demonstrated changes consistent with eosinophilic oesophagitis.

Results:

Both patients were expediently diagnosed, investigated and managed.

Conclusion:

A diagnosis of eosinophilic oesophagitis must be considered in patients presenting with food bolus impaction. Early involvement of a paediatric gastroenterology team in the diagnosis is recommended in children presenting with oesophageal symptoms, in order to avoid delayed diagnosis.
Orthographic and phonological effects in the picture–word interference paradigm: Evidence from a logographic language
Authors: BI YANCHAO , XU YAODA , CARAMAZZA ALFONSO
Published: July 2009

One important finding with the picture–word interference paradigm is that picture-naming performance is facilitated by the presentation of a distractor (e.g.,CAP) formally related to the picture name (e.g., “cat”). In two picture-naming experiments we investigated the nature of such form facilitation effect with Mandarin Chinese, separating the effects of phonology and orthography. Significant facilitation effects were observed both when distractors were only orthographically or only phonologically related to the targets. The orthographic effect was overall stronger than the phonological effect. These findings suggest that the classic form facilitation effect in picture–word interference is a mixed effect with multiple loci: it cannot be attributed merely to the nonlexical activation of the target phonological segments from the visual input of the distractor. It seems instead that orthographically only related distractors facilitate the lexical selection process of picture naming, and phonologically only related distractors facilitate the retrieval of target phonological segments.
Moodling beyond Bollywood: e-teaching the language, literature and culture of the Indian diaspora
Authors: Fischer-Hornung Dorothea , Brosius Christiane , Hundt Marianne , Mesthrie Rajend
Published: July 2009

A report on an interdisciplinary e-course experiment on language, literature and culture in the Indian Diaspora.

One of the rich potentials of the World Wide Web is to enable international and interdisciplinary projects by utilizing e-learning technologies. Further, contemporary students are used to structuring much of their public and private life and learning around the use of electronic technologies. Certainly, when learning, thinking and working are no longer solitary activities, then traditional notions of teaching must be redesigned throughout our educational institutions in order to meet the challenges of the communication age – language teaching and the humanities at our universities cannot be an. Since the classroom can transcend spatially limited locations, it can transform the ‘traditional scene of instruction […] into a joint venture involving many scholars, including our students as active researchers’.
Conference Report: The linguistics of English – setting the agenda
Authors: Kortmann Bernd , Schulz Monika
Published: July 2009

Report on the inaugural conference of the International Society for the Linguistics of English (Freiburg, Germany, 8–11 October 2008)
Epiphytes and hemiepiphytes have slower photosynthetic response to lightflecks than terrestrial plants: evidence from ferns and figs
Authors: Zhang Qiang , Chen Jun-Wen , Li Bao-Gui , Cao Kun-Fang
Published: July 2009

Photosynthetic responses of 12 species including six fern species (Neottopteris nidus, Microsorum punctatum, Pseudodrynaria coronans, Asplenium finlaysonianum, Paraleptochilus decurrens and Tectaria fauriei) and seedlings of six fig species (Ficus curtipes, F. gibbosa, F. altissima, F. auriculata, F. oligodon and F. hookeriana) in different life forms to lightfleck were investigated, to test whether epiphytes and hemiepiphytes display a slower response to lightfleck and fast induction loss after a lightfleck compared with their terrestrial counterparts, and whether ferns display a slower response to lightfleck and slower induction loss compared to figs. The measurements of functional traits and physiological parameters were determined in a screenhouse of 4% full sunlight. Epiphytic ferns and hemiepiphytic figs had thicker leaves compared with their terrestrial counterparts. Compared with figs, ferns had thicker fronds, larger stomata with a low density, and lower stomatal conductance and photosynthetic capacity; ferns had lower light compensation point and dark respiration rate, conferring a positive carbon gain under low diffuse light beneath the canopy. The induction time to reach 90% maximum net photosynthetic rate (T90) upon the exposure to a saturated light varied strongly among life forms. Epiphytic ferns had slower T90 than terrestrial ferns (19.9–26.3 vs 5.9–16.3 min, respectively), and hemiepiphytic figs had slower T90 than terrestrial figs (13.1–20.4 vs 5.2–7.8 min, respectively). Compared with figs, ferns showed a slower response to lightfleck. Across ferns and figs, the induction time was negatively correlated with initial stomatal conductance. No significant difference in induction loss was found between two life forms within ferns or figs, whereas ferns had a significantly slower induction loss compared with figs. These results showed that the inherent conservative water use strategy of the epiphytes and hemiepiphytes constrain their lightfleck utilization.
Effects of climate on pollination networks in the West Indies
Authors: González Ana M. Martín , Dalsgaard Bo , Ollerton Jeff , Timmermann Allan , Olesen Jens M. , Andersen Laila , Tossas Adrianne G.
Published: July 2009

We studied the effect of climate on the plant-pollinator communities in the West Indies. We constructed plots of 200 m × 5 m in two distinct habitats on the islands of Dominica, Grenada and Puerto Rico (total of six plots) and recorded visitors to all plant species in flower. In total we recorded 447 interactions among 144 plants and 226 pollinator species. Specifically we describe how rainfall and temperature affect proportional richness and importance of the different pollinator functional groups. We used three measures of pollinator importance: number of interactions, number of plant species visited and betweenness centrality. Overall rainfall explained most of the variation in pollinator richness and relative importance. Bird pollination tended to increase with rainfall, although not significantly, whereas insects were significantly negatively affected by rainfall. However, the response among insect groups was more complex; bees were strongly negatively affected by rainfall, whereas dipterans showed similar trends to birds. Bird, bee and dipteran variation along the climate gradient can be largely explained by their physiological capabilities to respond to rainfall and temperature, but the effect of climate on other insect pollinator groups was more obscure. This study contributes to the understanding of how climate may affect neotropical plant-pollinator communities.
Spatial and temporal variation in soil respiration in a seasonally dry tropical forest, Thailand
Authors: Adachi Minaco , Ishida Atsushi , Bunyavejchewin Sarayudh , Okuda Toshinori , Koizumi Hiroshi
Published: July 2009

Spatial and seasonal variation in soil respiration rates were investigated in a tropical dry forest in Thailand. The spatial variation was examined at 50 points within a 2-ha plot in the forest floor during the dry and wet seasons. The seasonal and diurnal variations in soil respiration were measured at 16 and 5 points, respectively. The mean soil respiration rate during the wet season was 1041 ± 542 mg CO2 m−2 h−1 (mean ± SD), which is about twice that during the dry season. Soil respiration rate was negatively correlated with soil water content during the wet season. A polynomial equation using seasonal data describes soil respiration and water content: soil respiration rate increased with soil water content, but started to drop when soil water content exceeded 21%. The diurnal variation in soil respiration rate during the wet season was positively correlated with soil temperature, whereas during the wet season it was not correlated with soil temperature. The diurnal variation in soil respiration rate during the dry season showed a midday depression. The estimation of soil carbon flux with polynomial equations should incorporate different functions for the wet and dry seasons in tropical dry forests.
LEARNER VERSUS NONLEARNER PATTERNS OF STYLISTIC VARIATION IN SYNCHRONOUS COMPUTER-MEDIATED FRENCH
Authors: van Compernolle Rémi A. , Williams Lawrence
Published: July 2009

This study analyzes stylistic variation among first-, second-, and third-year instructed learners of French engaged in synchronous French-language computer-mediated communication (CMC) and compares the results with data from nonlearner discourse in a public, noneducational synchronous CMC environment. We focus specifically on variability inyes/noquestion (YNQ) structures and the use of the pronounsnous“we” andon“one” or “we” for first-person plural reference. The results suggest that whereas first- and second-year learners rarely use informal variants, third-year students approximate—but do not actually reach—native-speaker norms. Contrary to expectations, however, no positive correlation was found between the increased use of the informal pronoun and the informal YNQ structure. Finally, we argue for more in-depth case studies that combine analyses of performance data, competence data, and individual learner histories to determine when, why, and how second language users begin to recognize and emulate native speakers’ sociolinguistic norms and variation.
Decoding Implications of the Genographic Project for Archaeology and Cultural Heritage
Authors: Nicholas George , Hollowell Julie
Published: July 2009

The panel began with an acknowledgment that we were assembled in the traditional territory of the Blood Nation. The panelists were then introduced and, in alphabetical order, gave their initial opening comments.
Property Rights of Ancient DNA: The Impact of Cultural Importance on the Ownership of Genetic Information
Authors: Elliott Lisa M.
Published: July 2009

This article examines the way property rights can be applied to DNA from ancient sources. In particular, it examines the ways in which the legal classification of a source as a “cultural artifact” can influence the assignment of property rights over genetic information. I explore the discrepancy between the legal ability to own ancient dead bodies but not nonancient dead bodies, illustrating how dead bodies with a perceived cultural value are legally distinct from those which are not considered to have cultural value. Second, I address the way such cultural preservation laws fail to influence ownership rights over genetic information. Finally, I propose a model for the best way to deal with genetic information from ancient sources, based on the policies of the International Ancient Egyptian Mummy Tissue Bank.
Closure of ventricular septal defects: a study of factors influencing spontaneous and surgical closure
Authors: Turner Stephen W. , Hornung Tim , Hunter Stewart
Published: July 2009

Introduction: Aspects of the management of ventricular septal defects which remain uncertain include the role of screening, and the need for closure of defects that remain patent. Aim: To ascertain the natural history of clinically significant ventricular septal defects, and to examine uncertainties in strategies of management. Methods: We studied prospectively a regional cohort of children born with isolated ventricular septal defects, noting age at presentation; sex; morphology and size of the defect; age at closure, if it occurred, and the means of closure. Results: We identified 290 children with isolated ventricular septal defects, of whom 147 (51%) were male. The mean follow up period was 65 months, with five cases being lost to follow up. Surgical closure was required in 41 (14%) cases, and 155 (54%) defects closed spontaneously. Spontaneous closure occurred in 123 (68%) out of 180 cases with completely muscular borders, and in 31 (29%) of the 107 patients with perimembranous defects. There were two cases with associated aortic regurgitation and no cases of endocarditis. Size and morphology of the defect were significant predictors of spontaneous and surgical closure. In addition, young age at diagnosis was a significant predictor of spontaneous closure. Conclusions: The size and morphology of a ventricular septal defect are important determinants of spontaneous closure and to the need for surgical intervention. Early age at presentation, in contrast, is not predictive of the need for surgical intervention. In early childhood, there appears to be very little risk of endocarditis or aortic valvar prolapse. Neither screening of populations to identify ventricular septal defects, nor surgical closure of asymptomatic defects in childhood, are supported by our findings.
Creation with a stent of an unrestrictive lasting atrial communication
Authors: Gewillig Marc , Boshoff Derize , Mertens Luc
Published: July 2009

A new technique is presented to create percutaneously an unrestrictive and lasting atrial communication in small children. In 2 infants, a stent was deployed in a restrictive atrial communication and first inflated with an 8 mm balloon. The stent was then further expanded up to 10 or 12 mm. The gradient and turbulent flow between the two atriums disappeared completely. The stent retained a very stable position without embolisation. Other complications, such as formation of thrombus or arrhythmia, were not observed until elective explantation after 2 and 11 months. We conclude that, in infants, dilation of the atrial septum with a stent can provide a safe, lasting, and unrestrictive atrial communication.
Measurement of the speed and attenuation of the Biot slow wave using a large ultrasonic transmitter
Authors: Bouzidi Youcef , Schmitt Douglas R.
Published: July 2009

Two compressional wave modes, a fast P1 and a slow P2, propagate through fluid‐saturated porous and permeable media. This contribution focuses on new experimental tests of existing theories describing wave propagation in such media. Updated observations of this P2 mode are obtained through a water‐loaded, porous sintered glass bead plate with a novel pair of ultrasonic transducers consisting of a large transmitter and a near‐point receiver. The properties of the porous plate are measured in independent laboratory experiments. Waveforms are acquired as a function of the angle of incidence over the range from −50° to +50° with respect to the normal. The porous plate is fully characterized, and the physical properties are used to calculate the wave speeds and attenuations of the P1, the P2, and the shear S waves. Comparisons of theory and observation are further facilitated by numerically modeling the observed waveforms. This modeling method incorporates the frequency and angle of incidence‐dependent reflectivity, transmissivity, and transducer edge effects; the modeled waveforms match well those observed. Taken together, this study provides further support for existing poroelastic bulk wave propagation and boundary condition theory. However, observed transmitted P1 and S mode amplitudes could not be adequately described unless the attenuation of the medium's frame was also included. The observed P2 amplitudes could be explained without any knowledge of the solid frame attenuation.
Passive detection of gamma ray shadows from small‐scale soil surface anomalies
Authors: Furey John , Morgan Cliff , Fields Morris
Published: July 2009

We exhibit theoretical and experimental evidence that some surface anomalies can be passively detected from their shadowing of low‐level gamma rays emitted from natural soil. Surface objects on the order of decimeter size with high electron density cause variable attenuation in several bands of gamma ray energies, while some surface holes cause other detectable changes in the gamma background. Using a broadly collimated portable 7.6 × 7.6 cm cylindrical NaI (Tl) scintillation detector, we characterize the small‐scale (on the order of meter scale or less) homogeneity of gamma rays at the soil surface in the context of detectability of objects and holes. We suggest that passive detection of anomalies below the surface may have impractically low count rates due to the greater collimation needed.
Seasonally resolved surface water Δ14C variability in the Lombok Strait: A coralline perspective
Authors: Guilderson T. P. , Fallon S. , Moore M. D. , Schrag D. P. , Charles C. D.
Published: July 2009

We have explored surface water mixing in the Lombok Strait through a bimonthly resolved surface water Δ14C time series reconstructed from a coral in the Lombok Strait that spans 1937 through 1990. The prebomb surface water Δ14C average is −60.5‰, and individual samples range from −72‰ to 134‰. The annual average postbomb maximum occurs in 1973 at 122‰. The timing of the postbomb maximum is consistent with a primary subtropical source for the surface waters in the Indonesian seas. During the postbomb period, the coral records regular seasonal cycles of 5‰ to 20‰. Seasonal high Δ14C occur during March–May (warm, low salinity), and low Δ14C occur in September (cool, higher salinity). The Δ14C seasonality is coherent and in phase with the seasonal Δ14C cycle observed in Makassar Strait. We estimate the influence of high Δ14C Makassar Strait (North Pacific) water flowing through the Lombok Strait using a two end‐member mixing model and the seasonal extremes observed at the two sites. The percentage of Makassar Strait water varies between 16% and 70%, and between 1955 and 1990, it averages at 40%. The rich Δ14C variability has a biennial component reflecting remote equatorial Indian Ocean forcing and a component in the ENSO band, which is interpreted to reflect Pacific forcing on the Δ14C signature in Lombok Strait.
Detection of flooding responses at the river basin scale enhanced by land use change
Authors: McCormick Brian C. , Eshleman Keith N. , Griffith Jeff L. , Townsend Philip A.
Published: July 2009

The Georges Creek watershed (area 187.5 km2) in western Maryland (United States) has experienced land use changes (>17% of area) associated with surface mining of coal. The adjacent Savage River watershed (area 127.2 km2) is unmined. Moments of flood frequency distributions indicated that climatic variability affected both watersheds similarly. Normalizing annual maximum flows by antecedent streamflow and causative precipitation helped identify trends in flooding response. Analysis of contemporary storm events using Next Generation Weather Radar (NEXRAD) stage III precipitation data showed that Georges Creek floods are characterized by higher peak runoff and a shorter centroid lag than Savage River floods, likely attributable to differences in current land use. Interestingly, Georges Creek produces only two thirds of the stormflow volume as Savage River, apparently because of infiltration into abandoned deep mine workings and an associated transbasin diversion constructed circa 1900. Empirical trend analysis is thus complicated by both hydroclimatic variability and the legacy of deep mining in the basin.
Leading modes of torsional oscillations within the Earth's core
Authors: Dickey Jean O. , de Viron Olivier
Published: July 2009

The fluid core motion cannot be observed directly, however, it can be deduced from magnetic observations. This motion can be approximated as a set of coaxial cylinders rotating along the Earth rotation axis. Our study shows that the actual motion in the core corresponds to a set of oscillations propagating from the core‐mantle boundary to the inner core (with diminishing amplitude) at period of 85, 50, 35 and 28 years, respectively. These oscillations appear to be very robust in our study, moreover two weaker modes have also been isolated and require further study. Zatman and Bloxham (1997) isolated two modes with periods that correspond to our first two modes. Comparing the theoretically predicted modes of Mound and Buffett (2007), all three analyses (one theoretically based and two based on geomagnetic observations) agree on the periods of the isolated modes; this concurrence is exceptional and provides strong evidence of the existence of the modes.
High‐speed video observations of rocket‐and‐wire initiated lightning
Authors: Biagi C. J. , Jordan D. M. , Uman M. A. , Hill J. D. , Beasley W. H. , Howard J.
Published: July 2009

We present observations of a rocket‐and‐wire triggered lightning flash obtained with high‐speed video cameras recording 5400 and 50000 frames per second (frame times 185 μs and 20 μs) with time‐synchronized current and electric field measurements. Transient leader channels were observed with precursor current pulses occurring before the development of the sustained upward positive leader that initiated the initial continuous current. The sustained upward positive leader stepped with a constant speed of 5.6 × 104 m s−1 over its initial 100 m. The wire destruction occurred discontinuously over a time of 7 ms about 45 ms after sustained upward leader inception, with a small change in channel current. Downward leaders, upward connecting leaders, and filamentary streamers were imaged in the bottom 50 m of the channel. We present the first images of a negative step forming in lightning, apparently involving a space stem similar to steps in meter‐length negative laboratory sparks.
Air‐sea interaction over the Atlantic warm pool in the NCEP CFS
Authors: Misra Vasubandhu , Chan Steven , Wu Renguang , Chassignet E.
Published: July 2009

This study shows that the SST variations in the July–August–September (JAS) peak season of the Atlantic Warm Pool (AWP) are modulated by the air‐sea fluxes. This feature is captured in the correlations between the rainfall and SST, and rainfall and SST tendency in the multi‐decadal integration of the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFS). Likewise, similar correlations are obtained from the NCEP CFS integration when latent heat flux is correlated with SST and SST tendency. However, when the same Atmospheric General Circulation Model as in the NCEP CFS (also called Global Forecast System [GFS]) is forced with observed SST, then the influence of air‐sea fluxes on SST is lost. Further analysis of observed air‐sea fluxes over the AWP region indicates that surface evaporation is weakly influenced by surface winds and air‐sea humidity variations. But in the NCEP CFS and more so in the NCEP GFS, the latent heat flux, contrary to observations, is strongly modulated by the air‐sea humidity variations.
Charge transfer and in‐cloud structure of large‐charge‐moment positive lightning strokes in a mesoscale convective system
Authors: Lu Gaopeng , Cummer Steven A. , Li Jingbo , Han Feng , Blakeslee Richard J. , Christian Hugh J.
Published: July 2009

Lightning observations in the very high frequency band and measurements of ultra low frequency magnetic fields are analyzed to investigate the charge transfer and in‐cloud structure of eight positive cloud‐to‐ground (+CG) strokes in a mesoscale convective system. Although no high altitude images were recorded, these strokes contained large charge moment changes (1500–3200 C·km) capable of producing nighttime sprites. Even though the convective region of the storm was where the flashes originated and where the CG strokes could occur, the charge transferred to ground was mainly from the stratiform region. The post‐stroke long continuing currents were connected to highly branched negative leader extension into the stratiform region. While the storm dissipated, the altitude of negative leader propagation in the stratiform area dropped gradually from 8 to 5 km, indicating that in some and perhaps all of these strokes, it was the upper positive charge in the stratiform region that was transferred.
A possible mechanism for the strong weakening of the North Atlantic subpolar gyre in the mid‐1990s
Authors: Lohmann Katja , Drange Helge , Bentsen Mats
Published: July 2009

The extent and strength of the North Atlantic subpolar gyre (SPG) changed rapidly in the mid‐1990s, going from large and strong in 1995 to substantially weakened in the following years. The abrupt change in the intensity of the SPG is commonly linked to the reversal of the North Atlantic Oscillation (NAO) index, changing from strong positive to negative values, in the winter 1995/96. In this study we investigate the impact of the initial SPG state on the subsequent behavior of the SPG by means of an ocean general circulation model driven by NCEP‐NCAR reanalysis fields. Our sensitivity integrations suggest that the weakening of the SPG cannot be explained by the change in the atmospheric forcing alone. Rather, for the time period around 1995, the SPG was about to weaken, irrespective of the actual atmospheric forcing, due to the ocean state governed by the persistently strong positive NAO during the preceding seven years (1989–1995). Our analysis indicates that it was this preconditioning of the ocean, in combination with the sudden drop in the NAO in 1995/96, that lead to the strong and rapid weakening of the SPG in the second half of the 1990s. This hypothesis explains the diverging evolution of the strength of the SPG and the atmospheric forcing (winter NAO) after 1995, as has been suggested recently.
Turbulence and intermittency in the heliospheric magnetic field in fast and slow solar wind
Authors: Yordanova E. , Balogh A. , Noullez A. , von Steiger R.
Published: July 2009

We study the nonuniform solar wind turbulence using high‐resolution Ulysses magnetic field data measured at different solar activity level, heliospheric latitudes, and distance. We define several types of solar wind dependent of the coronal region of origin and also of the dynamical behavior of the different streams, namely, “pure” fast wind, fast streams, “pure” slow wind, and slow streams. The turbulent properties of the solar wind types were investigated in terms of their scaling properties and spatial inhomogeneity. A clear trend in the power spectrum of the solar wind magnetic field magnitude is observed: the “pure” fast wind has a slope ∼−1.33 (1/f‐like), the fast streams ∼−1.48 (Kraichnan‐like), the “pure” slow wind ∼−1.67 (Kolmogorov‐like), and the slow streams ∼−1.72. We find that the “pure” fast wind in the polar heliolatitudes is less intermittent than the other types: “pure” slow wind and both slow and fast streams, which is because of the absence of dynamical interactions between streams with different speeds. On the other hand, fast streams are more intermittent than the “pure” fast wind, and slow streams are less intermittent than the “pure” slow winds. A clear radial and latitudinal evolution of the intermittency is observed only for the “pure” fast wind, while in the equatorial plane, the fast streams, the “pure” slow wind, and the slow streams do not show evolution either in heliolatitude or in heliocentric distance.
ARF stimulates XPC to trigger nucleotide excision repair by regulating the repressor complex of E2F4
Authors: Dominguez‐Brauer Carmen , Chen Yi‐Ju , Brauer Patrick M , Pimkina Julia , Raychaudhuri Pradip
Published: July 2009

The tumour suppressor ARF (alternative reading frame), which is mutated or silenced in various tumours, has a crucial role in tumour surveillance to suppress unwarranted cell growth and proliferation. ARF has also been linked to the DNA‐damage‐induced response of p53 because of its ability to inhibit murine double minute 2 (MDM2). Here, however, we provide genetic evidence for a role of ARF in nucleotide excision repair (NER) that is independent of p53. Cells lacking ARF are deficient in NER. Expression of ARF restores the repair activity, which coincides with increased expression of the damaged‐DNA recognition protein xeroderma pigmentosum, complementation group C (XPC). We provide evidence that, by disrupting the interaction between E2F transcription factor 4 (E2F4) and DRTF polypeptide 1 (DP1), ARF reduces the interaction of the E2F4–p130 repressor complex with the promoter of XPC to ensure high‐level expression of XPC. Together, our results point to an important ‘care‐taker’‐type tumour‐suppression function for ARF in NER through the increased expression of XPC.
Potential use of liposomal diallyl sulfide in the treatment of experimental murine candidiasis
Authors: Maroof Alam , Farazuddin Mohammad , Owais Mohammad
Published: July 2009

In the present study, we evaluated the potential of a liposomal formulation of the garlic oil component DAS (diallyl sulfide) in treating disseminated infection caused by the intracellular opportunistic pathogen Candida albicans in experimental mice. The PC (phosphatidylcholine) liposomal formulation of DAS was evaluated for size, ζ-potential, entrapment efficiency and release kinetics, toxicity etc. For therapeutic studies, mice were challenged with intravenous infection dosage of 107 blastospores of C. albicans followed by treatment with various doses of DAS formulations [12 and 6 mg/kg b.w. (body mass)] three times, on alternative days. The antifungal efficacy of liposomal DAS was assessed on the basis of survival of treated mice as well as the residual fungal load in vital organs like liver and spleen of mice. The results of the present study showed that treatment with DAS-bearing liposomes (12 mg/kg b.w.) resulted in the highest survival rate in animals. Liposomal DAS also significantly decreased residual fungal load in vital organs of experimental animals compared with the free form of DAS. The liposomal DAS was also found to be free of toxic manifestations as revealed by the erythrocyte lysis test and liver/kidney function tests. The results of the present study established that the antifungal activity of DAS, a poorly soluble compound, can be enhanced by the incorporation of it into liposomes. Further studies and optimizations are needed to build upon the promising findings of this study to enable the development of an effective plant-derived antifungal formulation that can provide an alternative to currently available antifungal drugs.
Significant enhancement of the strength-to-resistivity ratio by nanotwins in epitaxial Cu films
Authors: Anderoglu O. , Misra A. , Ronning F. , Wang H. , Zhang X.
Published: July 2009

Epitaxial nanotwinned Cu films, with an average twin spacing ranging from 7 to 16 nm, exhibit a high ratio of strength-to-electrical resistivity, ∼400 MPa(μΩ cm)−1. The hardness of these Cu films approaches 2.8 GPa, and their electrical resistivities are comparable to that of oxygen-free high-conductivity Cu. Compared to high-angle grain boundaries, coherent twin interfaces possess inherently high resistance to the transmission of single dislocations, and yet an order of magnitude lower electron scattering coefficient, determined to be 1.5–5×10−7 μΩ cm2 at room temperature. Analytical studies as well as experimental results show that, in polycrystalline Cu, grain refinement leads to a maximum of the strength-to-resistivity ratio, ∼250 MPa(μΩ cm)−1, when grain size is comparable to the mean-free path of electrons. However, in twinned Cu, such a ratio increases continuously with decreasing twin spacing down to a few nanometers. Hence nanoscale growth twins are more effective to achieve a higher strength-to-resistivity ratio than high-angle grain boundaries.
Impact of GaN cap thickness on optical, electrical, and device properties in AlGaN/GaN high electron mobility transistor structures
Authors: Waltereit P. , Müller S. , Bellmann K. , Buchheim C. , Goldhahn R. , Köhler K. , Kirste L. , Baeumler M. , Dammann M. , Bronner W. , Quay R. , Ambacher O.
Published: July 2009

We systematically investigate Al0.22Ga0.78N/GaN high electron mobility transistors with GaN cap layer thicknesses of 0, 1, and 3 nm. All samples have electron mobilities around 1700 cm2/Vs and sheet carrier concentrations around 8×1012 cm−2 as determined by Hall effect measurements. From photoreflectance measurements we conclude that the electric field strength within the AlGaN barrier increases with GaN cap layer thickness leading to a broadening of the transition peaks as determined by spectroscopic ellipsometry. The surface potential as determined by photoreflectance varies in the range between 0.585 and 0.249 eV dependent on the thickness of the GaN cap. Device results show a significant decrease in Ohmic contact resistance, an increase in ideality factor, a decrease in gate and drain leakage currents, an increase in gain, and an increase in power added efficiency with increasing cap layer thickness. Finally, devices with GaN cap show an improved direct current reliability compared to their counterparts without GaN cap.
Manipulation of C60 islands on the rutile TiO2 (110) surface using noncontact atomic force microscopy
Authors: Loske Felix , Kühnle Angelika
Published: July 2009

Regular, almost quadratic pits were created in an island of C60 molecules on a rutile TiO2 (110) surface using noncontact atomic force microscopy at room temperature. Upon gradually approaching the scanning tip toward the surface, the interaction between the tip and the C60 island was increased until manipulation was achieved. Analyzing the manipulation process unambiguously revealed that the manipulation was performed in the repulsive regime. Retracting the tip allowed for reproducible imaging the C60 island after the manipulation process. Moreover, whole islands could be reshaped or even removed when scanning with appropriate scanning parameters.
Gamma-ray burst has highest redshift yet seen
Authors: Schwarzschild Bertram
Published: July 2009

Bursts signaling the collapse of stars more than 13 billion years ago should elucidate early star formation and the cosmic reionization it engendered.
Anderson localization of ultracold atoms
Authors: Aspect Alain , Inguscio Massimo
Published: July 2009

To study localized matter waves, two experimental groups hold a Bose–Einstein condensate in the grip of a disordered but tunable optical potential formed by interfering laser beams.
Studying nuclear astrophysics at NIF
Authors: Boyd Richard N. , Bernstein Lee , Brune Carl
Published: July 2009

Scientists at the National Ignition Facility plan to generate fusion energy and study fusion in nuclear weapons. But the starlike conditions that NIF creates will also enable them to study astrophysically important nuclear reactions.
Latitudinal variation in lifespan within species is explained by the metabolic theory of ecology
Authors: Munch Stephan B. , Salinas Santiago
Published: July 2009

Many ectotherms exhibit striking latitudinal gradients in lifespan. However, it is unclear whether lifespan gradients in distantly related taxa share a common mechanistic explanation. We compiled data on geographic variation in lifespan in ectotherms from around the globe to determine how much of this intraspecific variation in lifespan may be explained by temperature using the simple predictions of the metabolic theory of ecology. We found that the metabolic theory accurately predicts how lifespan varies with temperature within species in a wide range of ectotherms in both controlled laboratory experiments and free-living populations. After removing the effect of temperature, only a small fraction of species showed significant trends with latitude. There was, however, considerable residual intraspecific variation indicating that other, more local factors are likely to be important in determining lifespan within species. These findings suggest that, given predicted increases in global temperature, lifespan of ectotherms may be substantially shortened in the future.
The DNA-gate of
Bacillus subtilis
gyrase is predominantly in the closed conformation during the DNA supercoiling reaction
Authors: Gubaev Airat , Hilbert Manuel , Klostermeier Dagmar
Published: July 2009

Gyrase is the only type II topoisomerase that introduces negative supercoils into DNA. Supercoiling is catalyzed via a strand-passage mechanism, in which the gate DNA (gDNA) is transiently cleaved, and a second DNA segment, the transfer DNA (tDNA), is passed through the gap before the gDNA is religated. Strand passage requires an opening of the so-called DNA-gate by ≈2 nm. A single-molecule FRET study reported equal populations of open and closed DNA-gate in topoisomerase II. We present here single-molecule FRET experiments that monitor the conformation of DNA bound to the DNA-gate of
Bacillus subtilis
gyrase and the conformation of the DNA-gate itself. DNA bound to gyrase adopts two different conformations, one slightly, one severely distorted. DNA distortion requires cleavage, but neither ATP nor the presence of a tDNA. At the same time, the DNA-gate of gyrase is predominantly in the closed conformation. In agreement with the single molecule data and with the danger of dsDNA breaks for genome integrity, <5% of cleavage complexes are detected in equilibrium. Quinolone inhibitors favor DNA cleavage by
B. subtilis
gyrase, but disfavor DNA distortion, and the DNA-gate remains in the closed conformation. Our results demonstrate that DNA binding, distortion and cleavage, and gate-opening are mechanistically distinct events. During the relaxation and supercoiling reactions, gyrase with an open DNA-gate is not significantly populated, consistent with gate-opening as a very rare event that only occurs briefly to allow for strand passage.
Allosteric modulation of DNA by small molecules
Authors: Chenoweth David M. , Dervan Peter B.
Published: July 2009

Many human diseases are caused by dysregulated gene expression. The oversupply of transcription factors may be required for the growth and metastatic behavior of human cancers. Cell permeable small molecules that can be programmed to disrupt transcription factor-DNA interfaces could silence aberrant gene expression pathways. Pyrrole-imidazole polyamides are DNA minor-groove binding molecules that are programmable for a large repertoire of DNA motifs. A high resolution X-ray crystal structure of an 8-ring cyclic Py/Im polyamide bound to the central 6 bp of the sequence d(5′-CCAGGCCTGG-3′)2 reveals a 4 Å widening of the minor groove and compression of the major groove along with a >18 ° bend in the heli
x
axis toward the major groove. This allosteric perturbation of the DNA helix provides a molecular basis for disruption of transcription factor-DNA interfaces by small molecules, a minimum step in chemical control of gene networks.
Rotavirus Infection in Neonates at a University Hospital in Korea
Authors: Kim Chang-Ryul , Oh Jae Won , Yum Myung Kul , Lee Jung Han , Kang Jung Oak
Published: July 2009

To develop measures to prevent neonatal rotavirus infection, we carried out rotavirus surveillance testing on all the newborns who were admitted to a newborn nursery in Korea during 1 year. We investigated the characteristics of neonatal rotavirus infection and found that it occurred throughout the year with the G4P[6] strain exclusively. Most newborns were infected nosocomially and showed no symptoms. We concluded that rotavirus might be transmitted from asymptomatic infected newborns who were born outside the hospital. We recommend isolation and rotavirus surveillance testing for all transfer patients.
Opium for the Masses: How Foreign Media Can Stabilize Authoritarian Regimes
Authors: Kern Holger Lutz , Hainmueller Jens
Published: July 2009

In this case study of the impact of West German television on public support for the East German communist regime, we evaluate the conventional wisdom in the democratization literature that foreign mass media undermine authoritarian rule. We exploit formerly classified survey data and a natural experiment to identify the effect of foreign media exposure using instrumental variable estimators. Contrary to conventional wisdom, East Germans exposed to West German television were more satisfied with life in East Germany and more supportive of the East German regime. To explain this surprising finding, we show that East Germans used West German television primarily as a source of entertainment. Behavioral data on regional patterns in exit visa applications and archival evidence on the reaction of the East German regime to the availability of West German television corroborate this result.
Long-lived sperm in the geothermal bryophyte
Pohlia nutans
Authors: Rosenstiel Todd N. , Eppley Sarah M.
Published: July 2009

Non-vascular plants rely on sperm to cross the distance between male and female reproductive organs for fertilization and sexual reproduction to occur. The majority of non-vascular plants have separate sexes, and thus, this distance may be a few millimetres to many metres. Because sperm need water for transport, it has been assumed that sperm lifespans are short and that this type of sexual reproduction limits the expansion of non-vascular plants in terrestrial environments. However, little data is available on the lifespan of sperm in non-vascular plants, and none is available for bryophytes, the group thought to have first colonized terrestrial habitats. Here, we documented the lifespan of sperm of
Pohlia nutans
, collected from a geothermal spring's area, and tested the effects of variation under environmental conditions on this lifespan. Surprisingly, 20 per cent of the sperm were still motile after 100 h, and sperm lifespan was not significantly affected by temperature variation between 22 and 60°C. Lifespan was significantly affected by sperm dilution and temperatures above 75°C. These results suggest the need to reconsider the importance of sperm motility in bryophyte fertilization.
Mutual assessment via visual status signals in
Polistes dominulus
wasps
Authors: Tibbetts Elizabeth A. , Mettler Alex , Levy Stephanie
Published: July 2009

Many animals use signals to assess the fighting ability of rivals and reduce the cost of aggressive competition. However, little is known about how an individual's own quality influences their signal assessment decisions.
Polistes dominulus
wasps have visual signals of fighting ability that provide a good model for testing the dynamics of rival choice. We found that rival assessment behaviour was influenced by the advertised quality of the individual, their rivals, and the interaction between individual and rival quality. Individuals of high advertised quality were more likely to challenge rivals and individuals of low advertised quality were more likely to be challenged. However, when choosing among two rivals with different advertised quality, individuals did not simply choose the lower quality rival. Instead, they only preferred the lower quality rival when there was a small difference between their own advertised quality and that of their rivals. Individuals were not choosy when both rivals advertised relatively high or relatively low quality. Therefore, although
P. dominulus
facial patterns function as conventional signals of fighting ability that provide valuable information about their bearer's behavioural strategy, there is substantial variation in signal responses based on the relative intensity of the senders' and receivers' signals.
Theoretical and numerical analysis of a spreading opposed-flow diffusion flame
Authors: Long Yang , Wichman Indrek S.
Published: July 2009

This article describes the macroscopic and microscopic features of flames spreading over solid-fuel surfaces by examining and comparing three models. The first model examines ignition and flame spread over a solid-fuel surface using a two-dimensional numerical simulation code. This model employs variable density, variable thermophysical properties and one-step global finite-rate chemistry. The second model, a macroscopic ‘field’ model, is solved in terms of the mixture fraction (
Z
) and total enthalpy (
H
) functions. Comparisons are made with numerical predictions for primitive quantities: temperature, species distributions and velocity fields; and derived quantities: heat flux, mass flux, mixture fraction, enthalpy function and flame stretch rate. The third model yields a ‘localized’ flame structure description near the flame attachment point. Theoretical formulas are produced for the quenching distance, the leading edge heat flux, and the flame structure, as characterized by reactivity, temperature field and species distributions. The analytical predictions are compared with numerical simulations to derive flame microstructure scaling parameters.
Synchronization of spontaneous eyeblinks while viewing video stories
Authors: Nakano Tamami , Yamamoto Yoshiharu , Kitajo Keiichi , Takahashi Toshimitsu , Kitazawa Shigeru
Published: July 2009

Blinks are generally suppressed during a task that requires visual attention and tend to occur immediately before or after the task when the timing of its onset and offset are explicitly given. During the viewing of video stories, blinks are expected to occur at explicit breaks such as scene changes. However, given that the scene length is unpredictable, there should also be appropriate timing for blinking within a scene to prevent temporal loss of critical visual information. Here, we show that spontaneous blinks were highly synchronized between and within subjects when they viewed the same short video stories, but were not explicitly tied to the scene breaks. Synchronized blinks occurred during scenes that required less attention such as at the conclusion of an action, during the absence of the main character, during a long shot and during repeated presentations of a similar scene. In contrast, blink synchronization was not observed when subjects viewed a background video or when they listened to a story read aloud. The results suggest that humans share a mechanism for controlling the timing of blinks that searches for an implicit timing that is appropriate to minimize the chance of losing critical information while viewing a stream of visual events.