bluuebunny/crossref_metadata_2025 huggingface dataset:
De Cordoue à Byzance
Authors: Rashed Marwan
Published: October 2008

The editing of three anonymous Greek texts preserved in theParisinus Suppl. gr.643 allows us to clarify certain ideas on the transmission of knowledge in the Mediterranean during the second half of the 13th century. These texts – an introduction to thePhysicsof Aristotle, one toDe generatione et corruptioneand a page ofMedical Problems– are in fact translations from Latin probably made at Salerno at the end of the Norman period or at the beginning of the Angevin dynasty. They allow us to establish the influence of the Parisian Faculty of Arts on the Sicilian intellectual milieu of the period and to illustrate how, whilst remaining true to its medical vocation, the University of Salerno evolved nonetheless towards a model of general education in the Arts. Finally these texts reveal the considerable influence – both philological and doctrinal – of Arabic learning on the Aristotelian teaching of their author. This very fact, combined with the presence of theParisinusin Byzantium, in an environment of advanced philological learning, a few decades after its composition, leads us to question our understanding of the Palaeologan Renaissance as well as its independence with regard to the Arabo-latin scholarly tradition of the 13th century.
Al-kindī on finding buried treasure
Authors: Burnett Charles , Yamamoto Keiji , Yano Michio
Published: October 2008

Al-Kindī contributed to the Arabic literature on methods of finding buried treasure. His short text on the subject has survived in two forms: a Letter, and a chapter of his astrological work known as The Forty Chapters. This article includes editions and translations of both these texts, as well as of the two Latin translations made of the chapter in The Forty Chapters and comments on the procedure advocated by al-Kindī.
La doctrine rhétorique d'Ibn Riḍwān et la Didascalia in Rhetoricam Aristotelis ex glosa Alpharabii
Authors: Aouad Maroun
Published: October 2008

Striking similarities, often literal, between Ibn Riḍwan's Book on the Application of Logic in the Sciences and Arts and the Didascalia in Rhetoricam Aristotelis ex glosa Alpharabii lead to suppose that the first of these treatises has preserved something of the Arabic source of the second one, the Great Commentary on the Rhetoric by al-Fārābī, and to question on the originality of Ibn Riḍwan's rhetorical doctrine. In this paper, the texts on rhetoric of Ibn Riḍwan's treatise are edited, translated and placed in front of their correspondents of the Didascalia. They are then analysed and classified depending on their proximity and distance to the Didascalia. It appears that Ibn Riḍwān has, as the Didascalia, a system of the means of the persuasion which puts on the same level eight non pathetical means external to the speech, the enthymeme and the example. Nervertheless, one has also to note that Ibn Riḍwan's theory of rhetoric is radically different from Didascalia's: on the one side, a general rhetoric – non limited to specific activity, means, listeners and objects; on the other side, a special rhetoric, with such limitations. On the basis of these similarities and differences, I shall treat, in the next issue of A.S.P., the degree of dependence of Ibn Riḍwān's rhetorical doctrine towards the Didascalia, and the project underlying his work.
La hiérarchie des degrés d'être chez Nicole Oresme
Authors: Celeyrette Jean , Mazet Edmond
Published: October 2008

N. Oresme passe pour l'un des rares (sinon le seul) grand universitaire médiéval mathématicien. C'est ainsi que son grand traité De Configurationibus qualitatum et motuum est vu traditionnellement comme un traité de mathématiques et analysé comme tel. En fait, l'examen de ses Questiones super Physicam montre qu'Oresme est un philosophe de la nature original. Ses thèses sont souvent en opposition avec celles de Buridan et saméthode est différente: ses arguments empruntent fort peu à la logique et presque exclusivement à la philosophie naturelle.
Alhazen Vulgarisé: Le De li aspecti d'un manuscrit du Vatican (moitié du XIVe siècle) et le troisième Commentaire sur l'optique de Lorenzo Ghiberti
Authors: Vescovini Graziella Federici
Published: October 2008

Dans sa description de l'œuvre en langue vulgaire de Lorenzo Ghiberti, Giorgio Vasari, quoiqu'il en dénigre certains aspects, saisit bien, nous semble-t-il, les traits marquants des Commentaires de Lorenzo, en particulier ceux du troisième livre concernant l'optique: Scrisse Lorenzo un'opera in volgare nella quale trattò di molte cose, ma sì fattamente che poco costrutto se ne cava… [que l'on en tire très peu de connaissances utiles…] Né tacerò che egli mostra il libro essere stato fatto da altri [Je ne tairai pas qu'il montre que le livre a été fait par d'autres personnes]
La doctrine rhétorique d'Ibn riḍwān et la Didascalia in Rhetoricam Aristotelis ex glosa Alpharabii (suite)
Authors: Aouad Maroun
Published: October 2008

Les correspondances littérales relevées dans I.R.M. et F.D.G. conduisent naturellement à se demander si elles sont le signe d'une parenté entre ces deux textes et, si c'est le cas, à s'interroger sur le degré d'originalité de la doctrine rhétorique du premier de ces traités.
Qui enseigne qui? (Lectures du Ḥayy b. Yaqẓān d'Ibn Ṭufayl)
Authors: Mallet Dominique
Published: October 2008

The author investigates the different readings of Ibn ṬufayPs epistle, Ḥayy b. Yaqẓan. Following a suggestion by L. Gauthier, who simply asked that the epistle should be read as a whole, the author adds Ṣalāḥ ‘Abd al- ḥabūr's reworking of the tale as a children's story to L. Gauthier's list of partial readings. The author juxtaposes Ṣalāḥ ‘Abd al- ḥabūr's reading, which does justice only to what Asāl taught Ḥayy, to G. Hourani's reading, which succeeds in reflecting only what Ḥayy taught Asāl. This impasse in the readings of Ḥayy b. Yaqẓān reveals what is missing, namely an understanding of the tale which fundamentally conforms to several of Alfarabi's teachings, though not to L. Gauthier's interpretation.
L'identité de l'intellect et de l'intelligible selon la version latine d'Averroés et son interprétation par Thomas d'Aquin
Authors: Wéber Édouard H.
Published: October 2008

The Aristotelian theme of the identity of the intellect and of the intelligibleis of the utmost importance in Averroes' noetics. This latter, studied in the Latin translations that the Latin philosophers of the thirteenth century scrutinized, rigourously develop this theme so as to preserve the supraempirical and transcendant character of necessary truth that human thinking identifies, thereto sacrificing the individual uniqueness of the intellective operation in its final instance. A Latin Master of the thirteenth century, Thomas Aquinas, adopts Averroes' insight into the transcendence of the noetic, and confirms it, even as he defends the strictly personal character of human intellection.
Al-qūhī Vs. Aristotle: On Motion
Authors: Rashed Roshdi
Published: October 2008

Al-Qūhī, mathematician of the 10th century, examines critically two arguments in the 6th book of the AristotelianPhysics. This critic does not follow the method of the philosophers, with doctrinal amendments, but with a mathematical and experimental style. For understanding of this critical examination and its influence, it is necessary to situate it in themathesisof al-Qūhī and to produce its mechanical presuppositions. This is the purpose of the author of this paper.
On the Difference of Expected Lengths of Minimum Spanning Trees
Authors: LI WENBO V. , ZHANG XINYI
Published: October 2008

An exact formula for the expected length of the minimum spanning tree of a connected graph, with independent and identical edge distribution, is given, which generalizes Steele's formula in the uniform case. For a complete graph, the difference of expected lengths between exponential distribution, with rate one, and uniform distribution on the interval (0, 1) is shown to be positive and of rate ζ(3)/n. For wheel graphs, precise values of expected lengths are given via calculations of the associated Tutte polynomials.
Resection of ventricular rhabdomyomas in infants presenting with cardiac failure
Authors: Dereddy Narendra R. , Sett Suvro S. , Krishnan Usha
Published: October 2008

Rhabdomyomas are the most common cardiac tumours in children. They sometimes cause significant obstruction of the ventricular out flow tracts. We report a series of 3 neonates diagnosed antenatally with multiple rhabdomyomas, who developed significant obstruction of the ventricular outflow tracts following birth. They underwent surgical resection in the neonatal period with good outcome. Antenatal diagnosis of obstructive cardiac tumours allows for planning for appropriate early intervention.
Home gardens management of key species in Nepal: a way to maximize the use of useful diversity for the well-being of poor farmers
Authors: Gautam R. , Sthapit B. , Subedi A. , Poudel D. , Shrestha P. , Eyzaguirre P.
Published: October 2008

The purpose of this study is to identify key home garden species in order to address basic research questions aimed at understanding farmers' home gardens management practices. The study was conducted in two contrasting Hill and Tarai sites in Nepal with households (HHs) ranging from 355 to 634. Unlike larger production systems, home gardens harbour many species in small areas often with a few crop varieties and species that are not well represented in larger fields. Given the number of species and their small population sizes, species and genetic diversity are best studied by identifying representative key species characterizing the complex productive niches within farms. Although species diversity within community is large (172–342), 24 key species were identified for the study. There is no fixed size of a home garden. The log of home garden size and species richness was positively correlated (r = 0.42,P < 0.001). Species richness was significantly higher in vegetable followed by fodder, fruits and spices. This paper also explores the diversity in home gardens to identify the composition and characteristics of the key species and how they are managed, used and conserved. Most of the farmers save the seeds of these home garden species for their own use, but many also exchange and buy and sell seed in local weekly market. Farmers' practices for selecting seed vary according to the reproductive biology of the key home garden species. Home gardens provide the HH with fresh and diverse supply of nutritious food, which improves their self-sufficiency, while conserving diversity on-farm. Despite this, they are neglected in research and development by policy makers and researchers.
Temperature and stable isotope variations in different water masses from the Alboran Sea (Western Mediterranean) between 250 and 150 ka
Authors: Gonzalez‐Mora Beatriz , Sierro Francisco J. , Schönfeld Joachim
Published: October 2008

Mg/Ca, Sr/Ca, and stable isotope measurements have been performed on tests from the planktonic foraminifers Globigerinoides ruber (white), Globigerina bulloides, and Neogloboquadrina pachyderma (right coiling) in samples from Ocean Drilling Program site 977A in the Alboran Sea (Western Mediterranean). The evolution of different water masses between 250 and 150 ka is described. Warm substages were characterized by strong seasonality and thermal stratification of the water column. By contrast, less pronounced seasonality and basin stratification seem to prevail during cold substages. Several periods of stratification due to the low salinity of the upper water mass occurred during the formation of organic‐rich layers and also during a possible Heinrich‐like event at 220 ka. The three foraminifer species studied show a common and large shell Sr/Ca variability in short timescales, suggesting changes in the global ocean Sr/Ca ratio as one of the main causes of variations in shell composition.
Modeling the topography of the salar de Uyuni, Bolivia, as an equipotential surface of Earth's gravity field
Authors: Borsa Adrian A. , Bills Bruce G. , Minster Jean‐Bernard
Published: October 2008

The salar de Uyuni is a massive dry salt lake that lies at the lowest point of an internal drainage basin in the Bolivian Altiplano. A kinematic GPS survey of the salar in September 2002 found a topographic range of only 80 cm over a 54 × 45 km area and subtle surface features that appeared to correlate with mapped gravity. In order to confirm the correlation between topography and gravity/geopotential, we use local gravity measurements and the EGM96 global geopotential model to construct a centimeter‐level equipotential surface corresponding to the elevation of the salar. Our comparison of GPS survey elevations with the equipotential surface estimate shows that 63% of the variance of the GPS elevations can be explained by equipotential surface undulations (and long‐wavelength error) in the EGM96 model alone, with an additional 30% explained by the shorter‐wavelength equipotential surface derived from local gravity. In order to establish a physical connection between topography and the geopotential, we also develop and test a simple surface process model that redistributes salt via the dissolution, transport, and redeposition of salt by precipitated water. Forcing within the model pushes the system to evolve toward constant water depth, with the salt surface approximating the shape of the local equipotential surface. Since the model removes almost all topographic relief with respect to the equipotential surface within a matter of decades, it appears that observed (∼5 cm amplitude, ∼5 km wavelength) residual topography is actively maintained by a process independent of gravity‐driven fluid flow.
Ocean acidification of the Greater Caribbean Region 1996–2006
Authors: Gledhill Dwight K. , Wanninkhof Rik , Millero Frank J. , Eakin Mark
Published: October 2008

The global oceans serve as the largest sustained natural sink for increasing atmospheric carbon dioxide (CO2) concentrations. As this CO2 is absorbed by seawater, it not only reacts causing a reduction in seawater pH (or acidification) but also decreases the carbonate mineral saturation state (Ω), which plays an important role in calcification for many marine organisms. Ocean acidification could affect some of the most fundamental biological and geochemical processes of the sea in coming decades. Observations obtained in situ from Volunteer Observing Ships and multiple geochemical surveys have been extended using satellite remote sensing and modeled environmental parameters to derive estimates of sea‐surface alkalinity (AT) and carbon dioxide partial pressure (pCO2,sw). Pairing estimates of AT and pCO2,sw have permitted characterization of the changes in sea‐surface Ω, which have transpired over the past decade throughout the Greater Caribbean Region as a consequence of ocean acidification. The results reveal considerable spatial and temporal variability throughout the region. Despite this variability, we observed a strong secular decrease in aragonite saturation state (Ωarg) at a rate of approximately −0.012 ± 0.001 Ωarg yr−1 (r2 = 0.97, P < 0.001).
Determination of most probable height of desert dust aerosol layer from space
Authors: Joseph Joachim H. , Yaron Ofer , Yaroslavich Eyal , Israelevich Peter , Koren Ilan , Yair Yoav , Devir Adam , Kischa Pavel
Published: October 2008

We have inferred the most probable height distribution in a set of eleven areas of desert dust aerosol plumes over the eastern tropical and subtropical Atlantic Ocean using multispectral outgoing reflected radiance data collected during the Mediterranean Israeli Dust Experiment (MEIDEX), conducted on board the STS‐107 space shuttle mission, from 16 January to 1 February 2003. It is shown that one can remotely infer the average height distribution of desert aerosol plumes from space in a specified atmospheric volume, if one has available calibrated, simultaneous, and co located radiances in the UV, the visible, and the NIR.
Geoneutrino Measurements and Models Investigate Deep Earth
Authors: Dye Stephen T. , McDonough William F. , Mahoney John
Published: October 2008

Two underground detectors, in Japan and Italy, are currently recording interactions of highly penetrating particles called geoneutrinos, which are naturally produced inside the Earth. By measuring the geoneutrino flux, these pioneering projects along with several other projects that are being planned are advancing constraints on the contribution of radioactive elements to Earth's heat budget in a novel way. The detector in Japan, which has been in operation the longest, now measures the geoneutrino flux with precision better than a model prediction. Future projects dedicated to measuring and modeling the planet's geoneutrino flux would define the amount and distribution of heat‐producing elements in the Earth and provide transformative insights into the thermal history and dynamic processes of the mantle.
Professional Development Training for Early Career Polar Researchers: Association of Polar Early Career Scientists Career Development Workshop; St. Petersburg, Russia, 7 July 2008
Authors: Thomas Elizabeth R. , Baeseman Jenny , Lantuit Hugues , Xavier Jose , Baker Narelle
Published: October 2008

One hundred early career researchers working in a range of disciplines met in Russia on 7 July for a career development workshop targeting polar researchers. The workshop was hosted by the Association of Polar Early Career Scientists (APECS) in collaboration with the Scientific Committee on Antarctic Research (SCAR) and the International Arctic Science Committee (IASC) as part of the SCAR/IASC Open Science Conference “Polar Research—Arctic and Antarctic Perspectives in the International Polar Year.”

Demands on early career researchers are increasing. They not only need to excel academically but must also compete for funding with well‐established researchers, foster collaborations, and communicate their research to a diverse audience of colleagues, peers, and funding agencies within and outside of their own disciplines and countries. Representatives from funding agencies and research councils including the U.S. National Science Foundation (NSF), the U.K. Natural Environment Research Council (NERC), Antarctica New Zealand, IASC, and SCAR ran sessions and panel discussions focusing on key skills in writing proposals, conducting remote and logistically complex fieldwork, communicating their science, and improving research productivity. Through this, early career researchers had the unique opportunity to question potential reviewers and employers about how best to succeed in polar science.
AGU: 89 Years of Dynamic Leadership
Authors: Anonymous
Published: October 2008

In its 89 years, AGU has matured and expanded through the dedicated administrative direction of three able leaders—John A. Fleming, Waldo E. Smith, and A. F. Spilhaus, Jr.—each with a vision of a strong scientific organization that serves individuals as they extend the knowledge and understanding of the Earth, the planets, and their space environments.

Between 1919 and 2008, thirty‐nine presidents, assisted by a host of other volunteers, have provided scientific leadership to AGU. However, a society also needs complementary operational leadership if it is to serve its membership effectively. AGU is unique in that since its founding just three men have given this guidance. Each was selected from the membership, each had prepared for a career in a chosen branch of geophysics, and each had a full appreciation of the unity of the geophysical sciences. Their primary focus was always on science, but their administrative talents enabled them to guide the growth of the Union from a select committee of the National Research Council to a major scientific society with broad international membership (see the membership growth chart and time line).
Representing subgrid‐scale edaphic heterogeneity in a large‐scale ecosystem model: A case study in the circumpolar boreal regions
Authors: Ise Takeshi , Sato Hisashi
Published: October 2008

Strong feedback interactions occur between terrestrial ecological processes and climate. However, vegetation dynamics have not been adequately reproduced by many large‐scale ecosystem models and coupled climate models because local environmental variations are not sufficiently considered. By estimating subgrid‐scale ecosystem productivity potentials within large grid cells, we explicitly incorporated local edaphic heterogeneity into the Spatially Explicit Individual‐Based Dynamic Global Vegetation Model (SEIB‐DGVM). We assumed that high‐resolution land cover data reflected the underlying ecosystem productivity potentials originating from edaphic variations. We categorized high‐resolution Global Land Cover 2000 database (GLC2000) pixels into high, intermediate, and low productivity potentials and obtained fractional cover of these potentials on a DGVM grid. Then we performed transient dynamic vegetation simulations on circumpolar boreal regions with high, intermediate, and low photosynthetic capacities. Using the productivity potentials as weight, we estimated total leaf area index (LAI) that integrates the smaller‐scale variation of each DGVM grid. Ground‐based observations and a remote sensing product were used to evaluate the model performance. The regional pattern of simulated LAI was significantly improved, especially for the North American boreal regions. Improvement was minor for northern Eurasia, suggesting the qualitative classification by GLC2000 was the critical control on our approach. The results suggested that even a rather simplistic consideration of subgrid‐scale heterogeneity could significantly improve large‐scale simulations.
Decadal change in the relationship between east Asian–western North Pacific summer monsoons and ENSO in the mid‐1990s
Authors: Yim So‐Young , Jhun Jong‐Ghap , Yeh Sang‐Wook
Published: October 2008

The decadal change in the summer monsoon system over the east Asia and western North Pacific is prominent since 1979 and predominantly associated with the sea surface temperature (SST) distribution of equatorial central and eastern Pacific. The monsoon system in the period 1979–1993 is mainly linked to the warming of SST in the NINO3 region (5°S–5°N, 150°W–90°W), which is associated with a combination of developing and decaying ENSO phases. On the other hand, that in the period 1994–2006 is associated with the SST warming in the NINO4 region (5°S–5°N, 160°E–150°W) during the developing ENSO phase. These features are obvious in both observations and model results.
Plasma environment of Mars as observed by simultaneous MEX‐ASPERA‐3 and MEX‐MARSIS observations
Authors: Dubinin E. , Modolo R. , Fraenz M. , Woch J. , Chanteur G. , Duru F. , Akalin F. , Gurnett D. , Lundin R. , Barabash S. , Winningham J. D. , Frahm R. , Plaut J. J. , Picardi G.
Published: October 2008

Simultaneous in situ measurements carried out by the Analyzer of Space Plasma and Energetic Atoms (ASPERA‐3) and Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instruments on board the Mars Express (MEX) spacecraft for the first time provide us with the local parameters of cold ionospheric and hot solar wind plasma components in the different regions of the Martian magnetosphere and ionosphere. On the dayside, plasma of ionospheric and exospheric origin expands to large altitudes and gets in touch with the solar wind plasma. Formation of the magnetic field barrier which terminates the solar wind flow is governed by solar wind. The magnetic field rises up to the value which is just sufficient to balance the solar wind pressure while the position of the magnetospheric boundary varies insignificantly. Although, within the magnetic barrier, solar wind plasma is depleted, the total electron density increases owing to the enhanced contribution of planetary plasma. In some cases, a load caused by a planetary plasma becomes so strong that a pileup of the magnetic field occurs in a manner which forms a discontinuity (the magnetic pileup boundary). Generally, the structure of the magnetospheric boundary on the dayside varies considerably, and this variability is probably controlled by the magnetic field orientation. Inside the magnetospheric boundary, the electron density continues to increase and forms the photoelectron boundary which sometimes almost coincides with the magnetospheric boundary. The magnetic field strength also increases in this region, implying that the planetary plasma driven into the bulk motion transports the magnetic field inward. A cold and denser ionospheric plasma at lower altitudes reveals a tailward cometary‐like expansion. Large‐amplitude oscillations in the number density of the ionospheric plasma are another typical feature. Crossings of plasma sheet at low altitudes in the terminator region are characterized by depletions in the density of the ionospheric component. In some cases, density depletions correlate with large vertical components of the crustal magnetic field. Such anticorrelation in the variations of the densities of the cold ionospheric and hot magnetosheath/plasma sheet plasmas is also rather typical for localized aurora‐type events on the nightside.
Modeling magnetospheric current response to solar wind dynamic pressure enhancements during magnetic storms: 2. Application to different storm phases
Authors: Shi Yong , Zesta Eftyhia , Lyons Larry R.
Published: October 2008

Two patterns of ground H perturbation as response to pressure enhancements during different phases of storms are found. One is polarity asymmetry under southward IMF Bz, e.g., 25 September 1998, 29 May 2003, and 10 January 1997 events; the other is positive H perturbation everywhere under northward IMF Bz, e.g., 7 November 2000 event. The polarity asymmetry can be further divided into two categories: dawn‐dusk asymmetry with negative H perturbation at dusk extending through noon to late morning (25 September 1998 event) and positive H perturbation elsewhere, and day‐night asymmetry with a smaller region of negative H perturbation extending less far toward dusk (29 May 2003 and 10 January 1997 events). The net field‐aligned current (FAC) system from the R1, R2, and the partial ring current (PRC) closure FAC, the equatorial portion of the PRC, and Chapman‐Ferraro (CF) current are responsible for the polarity asymmetry. The stronger effect of the R1 is primarily responsible for the negative H perturbation at noon and positive at midnight. The PRC strength at the onset of pressure enhancements determines how far the negative H perturbation at noon extends toward dusk and which pattern is most likely. A stronger (weaker) PRC extends negative H perturbation more (less) toward dusk and thus increases the likelihood of dawn‐dusk (day‐night) asymmetry. Positive H perturbation everywhere results from the dominant contribution of the CF and lack of significant preexisting PRC and R1 and R2.
On the sensitivity of cloud‐to‐ground lightning activity to surface air temperature changes at different timescales in São Paulo, Brazil
Authors: Pinto O. , Pinto I. R. C. A.
Published: October 2008

This paper presents a study about the sensitivity of cloud‐to‐ground (CG) lightning activity to changes in surface air temperature at daily, monthly, yearly, and decadal timescales in the city of São Paulo (Brazil). Lightning data collected in the city by the Brazilian Lightning Detection Network (BrasilDat) from 1999 to 2006 and thunderstorm day data obtained from 1951 to 2006 were analyzed and compared with surface air temperature data. The lightning activity increases significantly with increasing temperature, with a sensitivity of approximately 40% per 1°C for daily and monthly timescales and approximately 30% per 1°C for decadal timescale. For the yearly timescale, the increase is not statistically significant. The lower sensitivity for the decadal timescale suggests that the lightning sensitivity to changes in surface air temperature decreases for larger timescales, in agreement with what is expected on the basis of convective adjustment. The decadal lightning sensitivity found in this study is in reasonable agreement with the increase in the global lightning activity estimated by most climate models. The study is the first to investigate in detail this relationship in a large urban area inside the tropics and should contribute to the effort to understand the impact of the global warming on lightning activity.
Atmospheric circulation during active and break phases of Indian summer monsoon: A study using MST radar at Gadanki (13.5°N, 79.2°E)
Authors: Roja Raman M. , Jagannadha Rao V. V. M. , Venkat Ratnam M. , Kishore Kumar G. , Narendra Babu A. , Vijaya Bhaskara Rao S. , Prabhakara Rao N. , Narayana Rao D.
Published: October 2008

The unique facility of measuring vertical winds using Indian mesosphere, stratosphere, and troposphere (MST) radar along with zonal and meridional winds enables the study of atmospheric circulation over Gadanki (13.5°N, 79.2°E) during the Indian summer monsoon season. The mean meridional circulations during winter and monsoon seasons represent part of two different Hadley circulations. The winter Hadley cell is observed to be stable whereas the monsoon Hadley cell seems to vary and depends on the monsoon activity. During active phase of the monsoon, the Hadley cell extends to the north, and during weak phase, it extends to the south of the study region. The observed features are compared with the winds obtained from National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data. The present study emphasizes that the atmospheric circulation during monsoon season is to be studied separately for active and break phases.
Equifinality in parameterization of process‐based biogeochemistry models: A significant uncertainty source to the estimation of regional carbon dynamics
Authors: Tang Jinyun , Zhuang Qianlai
Published: October 2008

Numerical biogeochemistry models suffer from equifinality problem in their parameterizations using eddy flux tower data, which can contribute to diverged estimates of regional carbon dynamics. To date, the uncertainty in regional estimates propagated from the site‐level parameterization equifinality has not been well characterized. Here, we use a process‐based biogeochemistry model, the Terrestrial Ecosystem Model (TEM), and a Bayesian inference framework to quantify the influence of parameterization equifinality on the estimates of carbon dynamics in boreal forest ecosystems during the 20th century. By conducting three groups of ensemble regional simulations, we find that, given a certain climate data set being used, (1) in comparison to the effects of random noises in climate forcing, the regional uncertainty due to parameterization equifinality is remarkably greater, (2) the parameterization equifinality results in drastically different decadal variations in the estimation of carbon storage during the 20th century, and (3) the uncertainties associated with parameterization equifinality and random noises in climate forcing vary both spatially and seasonally. We conclude that the equifinality from site‐level parameterizations in biogeochemistry models is an important uncertainty source in estimating regional carbon dynamics. Simply extrapolating the site‐level parameterization to large spatial and temporal scales could bias the regional estimates irrespective of regional climate data sets used in our analysis. Ensemble process‐based biogeochemistry model simulations conditioned on observed ecosystem fluxes with Bayesian inference techniques could provide more serious estimates of regional carbon dynamics and their associated uncertainties.
Speech Restoration: An Interactive Process
Authors: Grataloup Claire , Hoen Michel , Veuillet Evelyne , Collet Lionel , Pellegrino François , Meunier Fanny
Published: October 2008

Purpose

This study investigates the ability to understand degraded speech signals and explores the correlation between this capacity and the functional characteristics of the peripheral auditory system.

Method

The authors evaluated the capability of 50 normal-hearing native French speakers to restore time-reversed speech. The task required them to transcribe two-syllable items containing temporal reversions of variable sizes, ranging from no reversion to complete reversion, increasing by half-syllable steps. In parallel, the functionality of each participant’s auditory efferent system was evaluated using contralateral suppression of click-evoked otoacoustic emissions.

Results

Perceptual accuracy for time-reversed speech diminished when the size of the applied temporal distortion increased. A lexical benefit was evident, and an important interindividual variability in performance was observed. Functional exploration of the auditory system revealed that speech restoration performances correlated with the suppression strength of the participant’s auditory efferent system.

Conclusions

These results suggest a clear relation between the functional asymmetry of the auditory efferent pathway (the right-side activity is greater than the left-side activity in right-handed participants) and the comprehension of acoustically distorted speech in normal-hearing participants. Further experiments are needed to better specify how the functionality of the medial olivocochlear bundle can cause phonological activation to be more efficient.
Narrow inhomogeneous broadening of V-groove quantum wires grown on vicinal substrates
Authors: Moret N. , Oberli D. Y. , Dwir B. , Rudra A. , Gallo P. , Kapon E.
Published: October 2008

Significant reduction in inhomogeneous broadening of GaAs/AlGaAs V-groove quantum wires (QWRs) is achieved by growing them on vicinal (001) GaAs substrates misaligned by several degrees with respect to the [11¯0] groove direction. Low temperature photoluminescence spectra exhibit QWR linewidths as low as 3.7 meV for subband separation of 41 meV and 3 meV for subband separation of 27 meV. Atomic force microscopy evidences a change in the growth dynamics as compared with QWRs made on exact (001) GaAs substrates. The impact of the different growth dynamics on the wire interface structure is discussed.
Quantification of self-sputtering and implantation during pulsed laser deposition of gold
Authors: Perea A. , Gonzalo J. , Budtz-Jørgensen C. , Epurescu G. , Siegel J. , Afonso C. N. , García-López J.
Published: October 2008

This work reports on the quantification of self-sputtering and implantation occurring during pulsed laser deposition of Au as a function of the laser fluence used to ablate the gold target. The experimental approach includes, on one hand, in situ electrical (Langmuir) and optical (two-dimensional imaging) probes for determining, respectively, ion and excited neutral kinetic energy distributions. On the other hand, it includes determination of the density of (i) ions reaching a substrate, and (ii) gold atoms deposited on a substrate as well as of a proportion of atoms that are self-sputtered. The experimental results supported by numerical analysis show that self-sputtering and implantation are both dominated by ions having kinetic energies ≥200 eV. They are a fraction 0.60–0.75 of the species arriving to the substrate for ablation laser fluences 2.7–9.0 J cm−2. Self-sputtering yields in the range 0.60–0.86 are determined for the same fluence range.
Role of pinning in current driven domain wall motion in wires with perpendicular anisotropy
Authors: Burrowes C. , Ravelosona D. , Chappert C. , Mangin S. , Fullerton Eric E. , Katine J. A. , Terris B. D.
Published: October 2008

Spatial and time resolved giant magnetoresistance measurements are used to detect thermally activated domain wall (DW) propagation along wires formed from spin valves having perpendicular magnetic anisotropy. We show that field- and current-induced DW propagation are both strongly influenced by the presence of pinning defects. As a result, the creep motion of DWs over macroscopic length scales is found to be stochastic. Only the combination of a high polarized current density and/or magnetic field allows DWs to propagate freely. These results may help explain low current-driven DW velocities observed in previous experiments.
Direct observation of the electronic states of single crystalline rubrene under ambient condition by photoelectron yield spectroscopy
Authors: Nakayama Yasuo , Machida Shinichi , Minari Takeo , Tsukagishi Kazuhito , Noguchi Yutaka , Ishii Hisao
Published: October 2008

The electronic states of single crystalline (SC) rubrene were experimentally observed by photoelectron yield spectroscopy without the sample charging problem. The ionization energy (Is) in the SC phase was determined to be 4.85(±0.05) eV, which is reduced by 0.45 eV compared to that of the amorphous film. The changes in the electronic states during photo-oxidation reaction and under ambient air were also observed directly to reveal the further reduction in Is, which can be attributed to the generation of polar oxide molecules and reversible physisorption of H2O, respectively.
The influence of 180° ferroelectric domain wall width on the threshold field for wall motion
Authors: Choudhury Samrat , Li Yulan , Odagawa Nozomi , Vasudevarao Aravind , Tian L. , Capek Pavel , Dierolf Volkmar , Morozovska Anna N. , Eliseev Eugene A. , Kalinin Sergei , Cho Yasuo , Chen Long-qing , Gopalan Venkatraman
Published: October 2008

Unlike ideal 180° ferroelectric walls that are a unit cell wide (∼0.5 nm), real walls in ferroelectrics have been reported to be many nanometers wide (1–10 nm). Using scanning nonlinear dielectric microscopy of lithium niobate (LiNbO3) and lithium tantalate (LiTaO3) ferroelectrics, we show that the wall width at surfaces can vary considerably and even reach ∼100 nm in places where polar defects adjoin a wall. The consequence of such variable wall widths is investigated on the specific property of threshold field required for wall motion. Using microscopic phase-field modeling, we show that the threshold field for moving an antiparallel ferroelectric domain wall dramatically drops by two to three orders of magnitude if the wall was diffuse by only ∼1–2 nm, which agrees with experimental wall widths and threshold fields for these materials. Modeling also shows that wall broadening due to its intersection with a surface will influence the threshold field for wall motion only for very thin films (1–10 nm) where the surface broadening influences the bulk wall width. Such pre-existing and slightly diffuse domain walls with low threshold fields for wall motion may offer a general mechanism to explain significantly lower experimental coercive fields for domain reversal in ferroelectrics as compared to the thermodynamic predictions.
Nanoparticle fabrication of hydroxyapatite by laser ablation in water
Authors: Musaev O. R. , Dusevich V. , Wieliczka D. M. , Wrobel J. M. , Kruger M. B.
Published: October 2008

Synthetic polycrystalline hydroxyapatite was ablated in water with 337 nm radiation from a UV nitrogen pulsed laser. According to transmission electron microscopy micrographs, the ablated particles were approximately spherical and had a size of ∼80 nm. Raman spectroscopic analysis demonstrated that particles had the same structure as the original crystal. X-ray photoelectron spectroscopy showed that the surface chemical composition was close to that of the original material. The characteristics of the ablated particles and estimations of the temperature rise of the hydroxyapatite surface under laser irradiation are consistent with the mechanism of explosive boiling being responsible for ablation. The experimental observations offer the basis for preparation of hydroxyapatite nanoparticles by laser ablation in water.
Ligand induced ferromagnetism in ZnO nanostructures
Authors: Wang Qian , Sun Qiang , Jena P.
Published: October 2008

Complementary to the experimental finding that ZnO nanoparticles become ferromagnetic when coated with N and S containing ligands such as dodecylamine and dodecanethiol [Garcia et al., Nano Lett. 7, 1489 (2007)], we provide the first theoretical understanding of the origin of magnetism in ligated ZnO nanoparticles as well as the structural properties of the ligated systems by using density functional theory and generalized gradient approximation for exchange and correlation, and a cluster model for the nanoparticles. We show that N or S atoms of the ligand bind to the Zn sites. The accompanying changes in the Zn–O bond length, hybridization between Zn 4s orbitals with N 2p or S 3p orbitals, and consequently the redistribution of charges between Zn and O atoms result in a magnetic system where the 2p electrons in O and N, and 3p electrons in S sites are spin polarized. Furthermore, the sites nearest to the Zn atom attached to the ligand carry bulk of the magnetic moment. Studies, as a function of cluster size, also illustrate that magnetism resides only on the surface. Our results confirm that the use of ligands can pave a new way for introducing magnetism in ZnO nanostructures, which can be used to develop magnetic sensors to detect N and S containing molecules.
Double layer in an expanding plasma: Simultaneous upstream and downstream measurements
Authors: Byhring H. S. , Charles C. , Fredriksen Å. , Boswell R. W.
Published: October 2008

Ion energy measurements were taken simultaneously using one retarding field energy analyzer placed at the open end of the plasma source, and one in the plasma diffusion region of an expanding low pressure argon plasma. An electric double layer was found, which is well separated from the region of high magnetic field and which is downstream of the maximum in the magnetic field gradient. An axially movable analyzer was used to determine the position of the double layer. It appears to be more closely connected to the rapid change in diameter from the source to the diffusion chamber, but still has a radial dimension close to that of the source diameter. These results suggest that the double layer forms, not as much as a result of a magnetic nozzle, but rather as a reaction to a dramatic change in boundary conditions. Still, a magnetic field of at least a few tens of Gauss in the double layer region is necessary for its spontaneous formation.
The effect of oxygen on ball milling of a near-equiatomic FeV sigma phase
Authors: Costa B. F. O. , Le Caër G. , Malaman B.
Published: October 2008

A coarse-grained near-equiatomic tetragonal sigma phase Fe48V52 is milled in argon in a vibratory mill with a small steady air supply. The oxygen content increases regularly at a rate of about 0.25at.%∕h. Besides a classical short step, during which the sigma phase transforms into an alpha phase, two main steps occur. During the first step, from ∼40to∼140h of milling, the bcc alpha phase is enriched in iron and heterogeneous because of a preferential oxidation of vanadium atoms. The bcc phase is partially amorphized as it is when milling in the absence of oxygen and nanocrystalline vanadium oxides do form. The second step is characterized by the coarsening of vanadium oxide particles and by the formation of ternary ferrous oxides. The results are discussed in the light of a vacancy mechanism proposed recently to account for the high stability of oxide nanoclusters in oxide dispersion strengthened Fe-based alloys processed by ball milling.
Vertical alignment nematic liquid crystal cell controlled by double-side in-plane switching with positive dielectric anisotropy liquid crystal
Authors: Shin Hun Ki , Kim Ki-Han , Yoon Tae-Hoon , Kim Jae Chang
Published: October 2008

We propose a vertical alignment liquid crystal cell controlled by double-side in-plane switching with a positive dielectric anisotropy liquid crystal material. In this structure, the pixel electrodes are interdigital electrodes, which are deposited on the bottom and top substrates parallel to each other. In the voltage-off state, the liquid crystal molecules are vertically aligned under the crossed polarizers; hence the cell appears to be dark. When an in-plane field is applied, the liquid crystal molecules tilt down to the left or right along the field direction, which is at 45° with respect to the input polarizer, giving rise to maximum transmission of the incident light. We fabricated the proposed cells, which show higher transmittance and lower driving voltage compared with the conventional vertical alignment configuration with a positive dielectric anisotropy liquid crystal. The improved electro-optical properties are due to the stronger in-plane field compared with the configuration having one-side electrode. In this device, the response time and viewing angle characteristics are almost the same as the conventional structure.
Single live cell refractometer using nanoparticle coated fiber tip
Authors: Lee Jung-Yan , Lee Chia-Wei , Lin En-Hong , Wei Pei-Kuen
Published: October 2008

We present a nano-optical probe for real-time refractive index measurement of single live cell. The probe was made of a tapered fiber tip coated with 13 nm diameter gold nanoparticles. The evanescent wave near the tip excited localized surface plasmon resonance of gold nanoparticles. By measuring the optical intensity scattered from the nanoparticles, the probe showed an intensity sensitivity up to ∼5400% per refractive index unit. The 3T3 fibroblast cell was tested by inserting the probe into the cytoplasm. Refractive index as measured by the localized plasmonic effect was 1.3506, consistent with the results measured by holographic methods.
Quantum-dot crystal defects
Authors: Kiravittaya S. , Schmidt O. G.
Published: October 2008

The authors investigate the formation of quantum-dot crystal (QDC) defects during the growth of two-dimensional QDCs on flat surfaces. The flat surface is modulated by the periodic strain fields of a buried quantum-dot (QD) seed layer, which in turn is grown onto a patterned substrate surface. Two types of QDC defects, QD vacancies, and QD interstitials are observed whenever the QD density controlled by the growth conditions does not match the areal density of the patterned sites. Our kinetic Monte Carlo growth simulations take into account the realistic strain profile of buried QDs and are able to describe the occurrence of both types of QDC defects during the growth of seeded QDCs.