bluuebunny/crossref_metadata_2025 huggingface dataset:
Buying time for wild animals with zoos
Authors: Conway William G.
Published: October 2010

Zoos and aquariums exhibit many rare species, but sustain few for long periods. Demanding genetic, demographic, and behavioral requirements are a part of the sustainability challenge, and historical zoo goals and limiting animal management objectives are another, but they have been overtaken by worldwide wildlife population contraction and endangerment. New policies are essential for zoo continuance and, if vanishing species are to be helped by zoo propagation, they must be given priority. However, zoos have little animal carrying capacity and propagation must be much more sharply focused. In addition, it is becoming urgent that zoos help to support parks and reserves and, where possible, manage some especially endangered species mutually with parks. Zoo Biol 29:1–8, 2010. © 2010 Wiley‐Liss, Inc.
Nerve guidance with versus without prepuncture ultrasound visualization for psoas compartment block and perineural catheter insertion: A randomized, prospective, blinded study
Authors: Tognù Andrea , Gullotta Stella , Danelli Giorgio , Borghi Battista , Niebel Thekla , Bonarelli Stefano , Melotti Rita M.
Published: October 2010

Lumbar plexus block may offer significant advantages in terms of postoperative analgesia, patient satisfaction, surgical outcome and patient rehabilitation. Ultrasound guidance has been used to describe psoas compartment block‐related anatomy and to estimate transverse process depth before needle insertion and prediction of actual needle‐to plexus intercept depth. The aim of this prospective randomized blinded study is to compare the Nerve‐Stimulation Guidance with versus without the Pre‐puncture Ultrasound Visualization in terms of onset time of the lumbar plexus sensory and motor block in patients undergoing total hip replacement.

46 patients undergoing total hip replacement were randomly allocated to receive posterior lumbar plexus block (LPB) using nerve stimulation guidance with (group US, n = 23) or without pre‐puncture ultrasound imaging (group NS, n = 23).

Onset time of sensory and motor blocks was recorded every 5 min for the first 30 min starting from the injection of the local anesthetic injection. Readiness for surgery was defined as complete numbness to pinprick test in the region supplied by the lumbar plexus and Bromage's score = 3.

Need for additional local anesthetic boluses or general anesthesia, intraoperative opioid consumption and first postoperative 24 h local anesthetic and rescue Analgesics consumption were also recorded.

The time required for the execution of the block was 3 (2–15) min in Group US and 5 (2–20) min in Group NS (p = 0.06). The mean time to readiness for surgery was 12 ± 5 in Group US and 19 ± 6 min in Group NS (p = 0.04) .3 Patients in Group US (13%) and 4 patients in Group NS (17%) (p = 0.73) required general anesthesia due to failed block. Intraoperative opioid consumption was similar in the two groups. There were no differences in complications, postoperative local anesthetic and rescue analgesics consumption and pain scores.

Nerve‐Stimulation technique combined with Pre‐puncture Ultrasound Visualization for continuous lumbar plexus blocks is comparable to Nerve‐Stimulation technique in terms of percentage of block success, intraoperative opioid consumption and postoperative pain relief. Pre‐puncture Ultrasound Visualization may reduce the time required for readiness to surgery.
NMR study of hydrogen exchange during the B–Z transition of a DNA duplex induced by the Zα domains of yatapoxvirus E3L
Authors: Lee Eun-Hae , Seo Yeo-Jin , Ahn Hee-Chul , Kang Young-Min , Kim Hee-Eun , Lee Yeon-Mi , Choi Byong-Seok , Lee Joon-Hwa
Published: October 2010

The Yaba‐like disease viruses (YLDV) are members of the Yatapoxvirus family and have double‐stranded DNA genomes. The E3L protein, which is essential for pathogenesis in the vaccinia virus, consists of two domains: an N‐terminal Z‐DNA binding domain and a C‐terminal RNA binding domain. The crystal structure of the E3L orthologue of YLDV (yabZαE3L) bound to Z‐DNA revealed that the overall structure of yabZαE3L and its interaction with Z‐DNA are very similar to those of hZαADAR1. Here we have performed NMR hydrogen exchange experiments on the complexes between yabZαE3L and d(CGCGCG)2 with a variety of protein‐to‐DNA molar ratios. This study revealed that yabZαE3L could efficiently change the B‐form helix of the d(CGCGCG)2 to left‐handed Z‐DNA via the active‐mono B–Z transition pathway like hZαADAR1.
Δ160p53 is a novel N‐terminal p53 isoform encoded by Δ133p53 transcript
Authors: Marcel Virginie , Perrier Stéphane , Aoubala Mustapha , Ageorges Sylvain , Groves Michael J. , Diot Alexandra , Fernandes Kenneth , Tauro Sudhir , Bourdon Jean-Christophe
Published: October 2010

p53 gene expresses several protein isoforms modulating p53‐mediated responses through regulation of gene expression. Here, we identify a novel p53 isoform, Δ160p53, lacking the first 159 residues. By knockdown experiments and site‐directed mutagenesis, we show that Δ160p53 is encoded by Δ133p53 transcript using ATG160 as translational initiation site. This hypothesis is supported by endogenous expression of Δ160p53 in U2OS, T47D and K562 cells, the latter ones carrying a premature stop codon that impairs p53 and Δ133p53 protein expression but not the one of Δ160p53. Overall, these results show that the Δ133p53 transcript generates two different p53 isoforms, Δ133p53 and Δ160p53.
The space and time frames of T cell activation at the immunological synapse
Authors: Valitutti Salvatore , Coombs Daniel , Dupré Loïc
Published: October 2010

The selective recognition of antigenic peptides by T cells requires the spatio/temporal integration of a panoply of molecular triggers. The space frame of T cell antigen receptors (TCR) interaction with peptide/MHC complexes (pMHC) displayed by antigen presenting cells is delineated by the micrometer‐scale area of the immunological synapse. The time frame of T cell stimulation is governed by a series of short TCR–pMHC interactions that are integrated into sustained signaling leading to productive activation. We discuss here how approaching antigen recognition from the time and space angles is key to the comprehension of the puzzling process of T cell activation.
L1CAM ubiquitination facilitates its lysosomal degradation
Authors: Schäfer Michael K.E. , Schmitz Brigitte , Diestel Simone
Published: October 2010

The cell adhesion molecule L1 is implicated in several processes in the developing and adult nervous system. Intracellular trafficking of L1 is important for cell migration, neurite growth and adhesion. We demonstrate here that L1 is ubiquitinated at the plasma membrane and in early endosomes. Mono‐ubiquitination regulates L1 intracellular trafficking by enhancing its lysosomal degradation. We propose that L1's ubiquitination might be an additional mechanism to control its re‐appearance at the cell surface thereby influencing processes like neurite growth and cell adhesion.
Locating the sciences in eighteenth-century Egypt
Authors: MURPHY JANE H.
Published: October 2010

In the last years of the eighteenth century, Egypt famously witnessed the practice of European sciences as embodied in the members of Bonaparte's Commission des sciences et des arts and the newly founded Institut d'Egypte. Less well known are the activities of local eighteenth-century Cairene religious scholars and military elites who were both patrons and practitioners of scientific expertise and producers of hundreds upon hundreds of manuscripts. Through the writings of the French naturalist Etienne Geoffroy Saint-Hilaire (1772–1844) and those of the Cairene scholar and chronicler ʿAbd al-Raḥmān al-Jabartī (1753–1825), I explore Egypt as a site for the practice of the sciences in the late eighteenth century, the palatial urban houses which the French made home to the Institut d'Egypte and their role before the French invasion, and the conception of the relationship between the sciences and social politics that each man sought. Ultimately, I argue that Geoffroy's struggle to create scientific neutrality in the midst of intensely tumultuous political realities came to a surprising head with his fixation on Paris asthesite for the practice of natural history, while al-Jabartī’s embrace of this entanglement of knowledge and power led to a vision of scientific expertise that was specifically located in his Cairene society, but which – as Geoffroy himself demonstrated – could be readily adapted almost anywhere.
Conjunctive agreement in Lamaholot
Authors: NISHIYAMA KUNIO
Published: October 2010

This paper presents a description and a theoretical analysis of agreement within coordination in Lamaholot (Austronesian), where the first conjunct agrees with the conjunction ‘and’. Conjunctive agreement is obligatory in the subject position but is optional in the object position. The analysis is couched in terms of markedness of case and proposes that the case of the subject (nominative) is unmarked compared to the case of the object (accusative), and that only unmarked case enables phi-features of the agreement control to be copied onto the agreement host. Apparent optionality is accounted for by manners of case spreading in coordination. Conjunctive agreement is also reported in the genetically unrelated but areally related language of Walman. Although conjunctive agreement originates in verbal agreement with the comitative function in both languages, it is shown that grammaticalization from the comitative to the conjunction is more advanced in Lamaholot, at least in terms of syntax and morphology.
A SPECTRAL METHOD FOR DECONVOLVING A DENSITY
Authors: Carrasco Marine , Florens Jean-Pierre
Published: October 2010

We propose a new estimator for the density of a random variable observed with an additive measurement error. This estimator is based on the spectral decomposition of the convolution operator, which is compact for an appropriate choice of reference spaces. The density is approximated by a sequence of orthonormal eigenfunctions of the convolution operator. The resulting estimator is shown to be consistent and asymptotically normal. While most estimation methods assume that the characteristic function (CF) of the error does not vanish, we relax this assumption and allow for isolated zeros. For instance, the CF of the uniform and symmetrically truncated normal distributions have isolated zeros. We show that, in the presence of zeros, the density is identified even though the convolution operator is not one-to-one. We propose two consistent estimators of the density. We apply our method to the estimation of the measurement error density of hourly income collected from survey data.
ORACLE-EFFICIENT NONPARAMETRIC ESTIMATION OF AN ADDITIVE MODEL WITH AN UNKNOWN LINK FUNCTION
Authors: Horowitz Joel L. , Mammen Enno
Published: October 2010

This paper describes an estimator of the additive components of a nonparametric additive model with an unknown link function. When the additive components and link function are twice differentiable with sufficiently smooth second derivatives, the estimator is asymptotically normally distributed with a rate of convergence in probability ofn−2/5. This is true regardless of the (finite) dimension of the explanatory variable. Thus, the estimator has no curse of dimensionality. Moreover, the asymptotic distribution of the estimator of each additive component is the same as it would be if the link function and the other components were known with certainty. Thus, asymptotically there is no penalty for not knowing the link function or the other components.
Distribution of phosphorus in an above-to-below-ground profile in a Bornean tropical rain forest
Authors: Imai Nobuo , Kitayama Kanehiro , Titin Jupiri
Published: October 2010

Ecosystem pool of phosphorus (P) was determined as the sum of above-ground vegetation, roots, necromass and soils to 1 m deep in a tropical rain forest in Sabah, Malaysia. Relationships among soil P fractions, acid phosphatase activity and fine-root biomass across soil horizons were also determined to understand P availability. Ecosystem pools of P, and of simultaneously quantified nitrogen (N) and carbon (C) were 3.4, 12 and 370 Mg ha−1, respectively. Only 2.6% of the total ecosystem P was in the above-ground vegetation, contrasting to C (60%) and N (16%). Canopy foliage of dominant tree species showed an extremely high N to P ratio of 31.5, which implied the excessively short supply of P compared with ample N. Soil P primarily consisted of recalcitrant occluded fractions (78–91%) and only 4% was labile. Approximately three-quarters of labile soil P was an organic fraction (Po). The concentration of labile Po did not differ between soil horizons, while both phosphatase activity and fine-root density were the greatest in the topsoil (top 5 cm) and dramatically decreased with depth. This suggests that trees depend on the acquisition of P from the labile Po in the topsoil, despite a greater amount of labile P in the subsoil. Trees with a high foliar N/P ratio may invest N to acquire P from the topsoil by secreting phosphatase that consists of proteins, rather than investing C to extending roots to scavenge P in the subsoil.
Experimental evidence that fire causes a tree recruitment bottleneck in an Australian tropical savanna
Authors: Prior Lynda D. , Williams Richard J. , Bowman David M. J. S.
Published: October 2010

A fire-mediated recruitment bottleneck provides a possible explanation for the coexistence of trees and grasses in mesic savannas. The key element of this hypothesis is that saplings are particularly vulnerable to fire because they are small enough to be top-killed by grass fires, but unlike juveniles, they take several years to recover their original size. This limits the number of recruits into the adult size classes. Thus savanna vegetation may be maintained by a feedback whereby fire restricts the density of adult trees and allows a grass layer to develop, which provides fuel for subsequent fires. Here, we use results from a landscape-scale fire experiment in tropical Australia, to explore the possible existence of a recruitment bottleneck. This experiment compared tree recruitment and survival over 4 y under regimes of no fire, annual early and annual late dry-season fire. Stem mortality decreased with increasing stem height in the fire treatments but not in the unburnt treatment. Tree recruitment was 76–84% lower in the fire treatments than the unburnt treatment. Such fire-induced stem loss of saplings and reduced recruitment to the canopy layer in this eucalypt savanna are consistent with the predictions of the fire-mediated recruitment bottleneck hypothesis.
Effect of host-bark extracts on seed germination in Tillandsia recurvata, an epiphytic bromeliad
Authors: Valencia-Díaz Susana , Flores-Palacios Alejandro , Rodríguez-López Verónica , Ventura-Zapata Elsa , Jiménez-Aparicio Antonio R.
Published: October 2010

Tree species are potential hosts for epiphytes; however in some forests epiphytes have a biased distribution among hosts. In a tropical dry forest of Mexico, previous research showed that there are trees with few epiphytes. It is possible that the bark of these hosts contain allelochemicals that influence epiphyte seed germination. The aims of this study were (1) to determine whether hosts with low epiphyte abundance (Ipomoea murucoides, I. pauciflora and Lysiloma acapulcense) would inhibit seed germination of Tillandsia recurvata through aqueous and organic bark extracts, (2) to determine whether germination of T. recurvata would differ among the hosts with low epiphyte abundance and a host with high epiphyte abundance (Bursera copallifera) and (3) to relate the chemical composition of organic bark extracts with inhibition of T. recurvata seed germination. Hexanic and dichloromethanic extracts were partially chemically characterized. Total phenolics and flavonoids concentrations of methanolic extracts were analysed. Aqueous and organic bark extracts from hosts with few epiphytes inhibited T. recurvata seed germination. Aqueous and dichloromethanic extracts of B. copallifera inhibited slightly the germination of T. recurvata. There was a positive correlation between concentration of flavonoids and inhibition of seed germination. Results suggest that a combination of compounds may be responsible for affecting the germination of T. recurvata. This study demonstrates the chemical effect of aqueous and organic bark extracts from hosts on germination of an epiphytic bromeliad.
Evidence of altitudinal moult-migration in a Central American hummingbird,Amazilia cyanura
Authors: Fraser K. C. , Diamond A. W. , Chavarría L.
Published: October 2010

For birds, moulting is an energetically costly endeavour (Murphy & King 1991), the timing and location of which may be flexible and governed by local ecological factors (Pyleet al. 2009, Rohweret al. 2005). Some species or individuals may pause during long-distance migration, or migrate specifically to moult (Greenberget al. 1974, Pyleet al. 2009, Rohweret al. 2005, 2008). This strategy may be most common when food abundance reaches a nadir at the end of the breeding period, promoting movement to areas where food is more plentiful and the energetic and nutritive demands of moult may be met more suitably (Rohweret al. 2005). This pattern is exemplified by insectivorous songbirds breeding in temperate, western North America that pause on southward migration to moult amidst the food flush that occurs following heavy rains in the Mexican monsoon region (Pyleet al. 2009, Rohweret al. 2005, 2009), or more rarely, migrate upslope after breeding to moult in more moist, productive areas at higher elevation (Butleret al. 2002, Greenberget al. 1974, Rohweret al. 2008, Steele & McCormick 1995). Such altitudinal migration may be much more common in the Neotropics where many species engage in seasonal shifts in elevation. Hypotheses proposed to explain this behaviour, however, have focused on links made between migration and a principally frugivorous or nectarivorous diet (Levey & Stiles 1992, Stiles 1985, 1988) and not on moult requirements or phenology. Fruit and nectar availability may vary seasonally over an elevational gradient, and birds may migrate in order to track peak abundances (Levey & Stiles 1992, Loiselle & Blake 1991). Hummingbirds may also track arthropod (particularly spider) abundance, but this possibility remains little explored (Cotton 2007, Stiles 1980).
Plant species selection by free-ranging cattle in southern Bolivian tropical montane forests
Authors: Marquardt Svenja , Beck Stephan G. , Encinas Felix D. , Alzérreca A. Humberto , Kreuzer Michael , Mayer Andrea C.
Published: October 2010

The frequency of selection of functional groups and plant species by free-ranging cattle foraging in a diverse environment and its changes during the dry and the following prehumid seasons were investigated using direct observations and bite counting. The study was conducted at two sites in the Bolivian–Tucuman montane forests in southern Bolivia, by including datasets of a total of 16 animals. Across both study sites and the entire observation period (May to October/November), the cattle were found to select a broad spectrum of plant species from different functional groups. However, just a limited number of species made up a considerable contribution to overall plant selection. The functional group of the graminoids was selected most frequently, but their contribution to plant selection decreased significantly from 63.5% of total bites in May to 15.9% in September/October, in accordance with a decrease in availability. Selection of woody plants (shrubs and tree parts, the latter mainly in the form of leaf litter and fruits) increased with time, reaching its peak at the beginning of the prehumid season, while the herbs showed a curvilinear pattern of selection which was highest in August. Plant species belonging to the functional groups of ferns, climbers and epiphytes were also selected by the cattle, but generally at low relative proportions. Plant selection might be influenced by temporal differences in nutritional quality and availability of the preferred plant species and functional groups. Sampling behaviour seems to be the most likely reason for the inclusion of a broad range of plant species with overall low contribution to plant selection.
Evidence for tolerance of parasitism in a tropical cavity-nesting bird, planalto woodcreeper (Dendrocolaptes platyrostris), in northern Argentina
Authors: Norris Andrea R. , Cockle Kristina L. , Martin Kathy
Published: October 2010

Avian hosts may either resist the negative effects of nestling ectoparasites by minimizing the number of parasites, or tolerate parasitism by increasing their fecundity via the reproductive compensation hypothesis. Little is known about the interactions between ectoparasites and their avian hosts in the tropics. We (1) examined nestling development rates, and tested whether (2) parasitism by a subcutaneous ectoparasitic botfly (Philornissp.) had negative effects on the condition of nestlings, and (3) these negative effects were minimized in larger broods in a tropical cavity-nesting bird, the planalto woodcreeper (Dendrocolaptes platyrostris), in primary and secondary Atlantic forests in the northern province of Misiones, Argentina. Nestling mass and ectoparasite load per nestling reached maxima when nestlings (n = 50) were between 10 and 14 d old. General linear mixed models predicted that mass at fledging declined with increasing nestling parasite load, suggesting that botflies had a negative influence on fledging condition. Parasite load per nestling declined with increasing brood size indicating that woodcreepers that increase their reproductive output minimize the negative effects of parasitism. Overall we found evidence to support the tolerance via reproductive compensation hypothesis. Future tests of the reproductive compensation hypothesis may help determine the underlying mechanism of the observed negative correlation between parasite load of nestlings and brood size.
Class-based approach to disambiguating Levin verbs
Authors: LI JIANGUO , BREW CHRIS
Published: October 2010

Lapata and Brew (Computational Linguistics, vol. 30, 2004, pp. 295–313) (hereafter LB04) obtain from untagged texts a statistical prior model that is able to generate class preferences for ambiguous Lewin (English Verb Classes and Alternations: A Preliminary Investigation, 1993, University of Chicago Press) verbs (hereafter Levin). They also show that their informative priors, incorporated into a Naive Bayes classifier deduced from hand-tagged data (HTD), can aid in verb class disambiguation. We re-analyse LB04's prior model and show that a single factor (the joint probability of class and frame) determines the predominant class for a particular verb in a particular frame. This means that the prior model cannot be sensitive to fine-grained lexical distinctions between different individual verbs falling in the same class.

We replicate LB04's supervised disambiguation experiments on large-scale data, using deep parsers rather than the shallow parser of LB04. In addition, we introduce a method for training our classifier without using HTD. This relies on knowledge of Levin class memberships to move information from unambiguous to ambiguous instances of each class. We regard this system as unsupervised because it does not rely on human annotation of individual verb instances. Although our unsupervised verb class disambiguator does not match the performance of the ones that make use of HTD, it consistently outperforms the random baseline model. Our experiments also demonstrate that the informative priors derived from untagged texts help improve the performance of the classifier trained on untagged data.
Automatic discovery of word semantic relations using paraphrase alignment and distributional lexical semantics analysis
Authors: DIAS GAËL , MORALIYSKI RUMEN , CORDEIRO JOÃO , DOUCET ANTOINE , AHONEN-MYKA HELENA
Published: October 2010

Thesauri, which list the most salient semantic relations between words, have mostly been compiled manually. Therefore, the inclusion of an entry depends on the subjective decision of the lexicographer. As a consequence, those resources are usually incomplete. In this paper, we propose an unsupervised methodology to automatically discover pairs of semantically related words by highlighting their local environment and evaluating their semantic similarity in local and global semantic spaces. This proposal differs from all other research presented so far as it tries to take the best of two different methodologies, i.e. semantic space models and information extraction models. In particular, it can be applied to extract close semantic relations, it limits the search space to few, highly probable options and it is unsupervised.
The automatic identification of lexical variation between language varieties
Authors: PEIRSMAN YVES , GEERAERTS DIRK , SPEELMAN DIRK
Published: October 2010

Languages are not uniform. Speakers of different language varieties use certain words differently – more or less frequently, or with different meanings. We argue that distributional semantics is the ideal framework for the investigation of such lexical variation. We address two research questions and present our analysis of the lexical variation between Belgian Dutch and Netherlandic Dutch. The first question involves a classic application of distributional models: the automatic retrieval of synonyms. We use corpora of two different language varieties to identify the Netherlandic Dutch synonyms for a set of typically Belgian words. Second, we address the problem of automatically identifying words that are typical of a given lect, either because of their high frequency or because of their divergent meaning. Overall, we show that distributional models are able to identify more lectal markers than traditional keyword methods. Distributional models also have a bias towards a different type of variation. In summary, our results demonstrate how distributional semantics can help research in variational linguistics, with possible future applications in lexicography or terminology extraction.
Histological and Stereological Characterization of Brown Trout (Salmo truttaf.fario) Trunk Kidney
Authors: Resende Albina D. , Lobo-da-Cunha Alexandre , Malhão Fernanda , Franquinho Filipa , Monteiro Rogério A.F. , Rocha Eduardo
Published: October 2010

The large variability in kidney morphology among fish makes it difficult to build a “universal” model on its function and structure. Therefore, a morphological study of brown trout trunk kidney was performed, considering potential seasonal and sex effects. Three-year-old specimens of both sexes were collected at four stages of their reproductive cycle. Kidney was processed for light and electron microscopy. The relative volumes of renal components, such as renal corpuscles and different nephron tubules, were estimated by stereological methods. Qualitatively, the general nephron structure of brown trout was similar to that described for other glomerular teleost species. Quantitatively, however, differences in the relative volume of some renal components were detected between sexes and among seasons. Particularly, highest values of vacuolized tubules and new growing tubules were observed after spawning, being more relevant in females. Despite seasonal changes, more linear correlations were found between those parameters and the reno-somatic index than the gonado-somatic index. Thus, we verified that some brown trout renal components undergo sex dependent seasonal variations, suggesting a morphological adaptation of the components to accomplish physiological needs. These findings constitute a baseline for launching studies to know which factors govern the morphological variations and their functional consequences.
A tremor and slip event on the Cocos‐Caribbean subduction zone as measured by a global positioning system (GPS) and seismic network on the Nicoya Peninsula, Costa Rica
Authors: Outerbridge Kimberly C. , Dixon Timothy H. , Schwartz Susan Y. , Walter Jacob I. , Protti Marino , Gonzalez Victor , Biggs J. , Thorwart Martin , Rabbel Wolfgang
Published: October 2010

In May 2007 a network of global positioning systems (GPS) and seismic stations on the Nicoya Peninsula, of northern Costa Rica, recorded a slow‐slip event accompanied by seismic tremor. The close proximity of the Nicoya Peninsula to the seismogenic part of the Cocos‐Caribbean subduction plate boundary makes it a good location to study such events. Several centimeters of southwest motion were recorded by the GPS stations over a period of several days to several weeks, and the seismic stations recorded three distinct episodes of tremor during the same time span. Inversion of the surface displacement data for the depth and pattern of slip on the plate interface shows peak slip at a depth of 25–30 km, downdip of the main seismogenic zone. Estimated temperatures here are ∼250°–300°C, lower than in other subduction zones where events of this nature have been previously identified. There may also be a shallower patch of slip at ∼6 km depth. These results are significant in that they are the first to suggest that slow slip can occur at the updip transition from stick slip to stable sliding, and that a critical temperature threshold is not required for slow slip. Tremor and low‐frequency earthquake locations are more difficult to determine. Our results suggest they occur on or near the plate interface at the same depth range as the deep slow slip, but not spatially colocated.
Temporal variations in water resources in the Yangtze River (Changjiang) over the Industrial Period based on reconstruction of missing monthly discharges
Authors: Yang S. L. , Liu Z. , Dai S. B. , Gao Z. X. , Zhang J. , Wang H. J. , Luo X. X. , Wu C. S. , Zhang Z.
Published: October 2010

To evaluate the response of river discharge to anthropogenic impacts and climate variability over the Industrial Period, we reconstructed past series of monthly discharge from three gauges on the main river of the Yangtze by means of regression (making use of the cross correlation among the gauges) and analyzed the integrated data (the observed series of discharge with missing values filled by reconstructed values) for the period 1865–2008 in relation to human activities and climate variability. The correlative coefficients between observed and predicted discharges at the three stations for the gauging period are R2 = 0.90–0.96 (n = 827–1557). The integrated time series of discharge to the sea shows periodicities of ∼7, ∼14, and ∼38 years, and we found significant decreasing trends in annual discharge (−11%) and monthly discharge from August to November (−47% for November) and an increasing trend in discharge in January (+30%) and February during the dry season. These trends are mainly attributed to human impacts, in particular, reservoir construction and water consumption. It is estimated that these trends will continue in the future decades of this century because of the influence of the South‐to‐North Water Diversion Project as well as increased water consumption and the construction of new dams within the river basin.
A correlation method for volcanic ash detection using hyperspectral infrared measurements
Authors: Clarisse Lieven , Prata Fred , Lacour Jean‐Lionel , Hurtmans Daniel , Clerbaux Cathy , Coheur Pierre‐François
Published: October 2010

Remote satellite detection of airborne volcanic ash is important for mitigating hazards to aviation and for calculating plume altitudes. Infrared sounders are essential for detecting ash, as they can distinguishing aerosol type and can be used day and night. While broadband sensors are mainly used for this purpose, they have inherent limitations. Typically, water and ice can mask volcanic ash, while wind blown dust can yield false detection. High spectral resolution sounders should be able to overcome some of these limitations. However, existing detection methods are not easily applicable to hyperspectral sounders and there is therefore a pressing need for novel techniques. In response, we propose a sensitive and robust volcanic ash detection method for hyperspectral sounders based on correlation coefficients and demonstrate it on IASI observations. We show that the method differentiates ash from clouds and dust. Easy to implement, it could contribute to operational volcanic hazard mitigation.
On the consistency of satellite measurements of thermospheric composition and solar EUV irradiance with Australian ionosonde electron density data
Authors: Richards P. G. , Meier R. R. , Wilkinson P. J.
Published: October 2010

Using a comprehensive ionosphere model, we demonstrate that satellite measurements of solar EUV irradiances, neutral densities, and temperatures are consistent with Australian ionosonde measurements of the electron density from 2002 to 2006. Our approach is to adjust the model neutral densities and temperature to determine the changes that are needed to reproduce the electron density. These model‐derived neutral densities and temperatures are found to agree well with measurements of neutral density and temperatures from the GUVI instrument on the TIMED satellite for both magnetically quiet and disturbed conditions. This technique opens up the prospect of using the vast ionosonde database to improve temporal variations of empirical models of the thermosphere during magnetic storms. It could also help validate key global general circulation models of the thermosphere and ionosphere. The model calculations also demonstrate the importance of vibrationally excited N2 in the ionosphere. It is particularly important in producing negative ionosphere storms and also helps explain the rapid recovery after the storms.
Scaling of asymmetric magnetic reconnection: Kinetic particle‐in‐cell simulations
Authors: Malakit K. , Shay M. A. , Cassak P. A. , Bard C.
Published: October 2010

Recently, Cassak and Shay (2007) applied a generalized Sweet‐Parker analysis to derive scaling laws for gross properties of asymmetric magnetic reconnection, including the reconnection rate, outflow speed, and outflow density. This study presents the first comprehensive test of this scaling theory using fully electromagnetic particle‐in‐cell simulations of antiparallel asymmetric magnetic reconnection. By varying the upstream densities and magnetic fields, we find that the reconnection rates, outflow speeds, and outflow densities are consistent with the general scaling theory. This implies that kinetic electron and proton physics beyond the Hall term does not fundamentally alter the gross properties of the asymmetric diffusion region as understood in Cassak and Shay (2007). In addition, the results confirm the validity of the assumption of mixing of particles on recently reconnected flux tubes, which is of key importance for accurately predicting the location of the flow stagnation point in the diffusion region.
Plasma flow during the brightening of proton aurora in the cusp
Authors: Taguchi S. , Hosokawa K. , Suzuki S. , Tawara A. , Frey H. U. , Matzka J. , Yukimatu A. S. , Sato N.
Published: October 2010

On the basis of simultaneous observations from the Super Dual Auroral Radar Network (SuperDARN), the far ultraviolet instrument on the IMAGE spacecraft, and a magnetometer installed on the east coast of Greenland, we present the characteristics of plasma flow during a westward moving proton aurora in the cusp, observed on 28 July 2000. Data with a time resolution of 12 and 25 s from SuperDARN at Þykkvibær, Iceland, show that the flow having a poleward component, which was accompanied by a quick equatorward expansion of the flow region, occurred in the early stages (approximately 1.5 min) of the brightening. Data from the magnetometer from a ground station on the Greenland east coast, which is located a few hundred kilometers west of the radar's field of view, show perturbations that are consistent with equatorward flow overhead, coincident with the expansion. The presence of flow vectors in opposite directions suggests that vortical flow was present during the proton aurora. Evidence supporting the suggested flow pattern has been found in an event recorded by the Greenland west coast magnetometer chain and in a cusp pass of the DE 2 spacecraft in the literature. We attribute the moving proton aurora to the traveling bulge at the polar cap boundary, which is the footprint of a flux transfer event, and imply that the preexisting vortical flow may be intensified when it becomes inflow to the bulge.
Estimation of the Atlantic inflow through the Strait of Gibraltar from climatological and in situ data
Authors: Soto‐Navarro Javier , Criado‐Aldeanueva Francisco , García‐Lafuente Jesús , Sánchez‐Román Antonio
Published: October 2010

Atmospheric data from reanalysis, satellite, and experimental observations have been combined to calculate a four‐year time series of the Atlantic inflow through the Strait of Gibraltar. The net flow through the strait, estimated from the Mediterranean water budget, and the Mediterranean outflow, estimated from currentmeter observations in Espartel sill (western Strait of Gibraltar) from October 2004 to January 2009, made it possible to estimate the Atlantic inflow as the sum of both of them. The obtained mean net flow is 0.038 ± 0.007 Sv, with a seasonal cycle of 0.042 ± 0.018 Sv annual amplitude and maximum in September. The Mediterranean outflow shows a seasonal signal with annual amplitude of 0.027 ± 0.015 Sv peaking in April (in absolute value), and a mean value of −0.78 ± 0.05 Sv. The resulting Atlantic inflow has a mean value of 0.81 ± 0.06 Sv and a seasonal cycle with annual amplitude of 0.034 ± 0.011 Sv, peaking in September, and high interannual variability. The inflow seasonal cycle is the result of a barotropic forcing associated with the cycle of the net flow, driven by the evaporative cycle, and a baroclinic forcing linked to the seasonal cycle of the reduced gravity that drives the exchange.
A pressure measurement method for high‐temperature rock vapor plumes using atomic line broadening
Authors: Kurosawa Kosuke , Sugita Seiji
Published: October 2010

Knowledge of pressure conditions is essential in understanding phase changes and chemical reactions. Although several methods have been proposed for the measurement of pressure in impact‐induced vapor plumes, they are somewhat unreliable. In this study, we developed a pressure measurement method for vapor clouds based on spectral line broadening. Under the nearest neighbor approximation, it is possible to analytically express the full width at half maximum as a function of the perturber number density. On the basis of these relations and spectroscopic constants of atomic emission lines of Fe I at 381.58 nm and Ca I at 646.26 nm, quadratic Stark broadening is the dominant broadening mechanism if the degree of ionization exceeds 1%. Resonance broadening and van der Waals broadening should be considered if the degree of ionization is less than 1%. Taking into account the appropriate broadening mechanisms, it is possible to accurately measure the pressure in vapor clouds. We conducted laser ablation experiments using the proposed pressure measurement method in combination with the Boltzmann plot method for temperature. The obtained pressures and temperatures are consistent with an adiabatic expansion. This strongly suggests that the proposed method can measure pressure of vapor clouds accurately. Because thermodynamic quantities can be determined when both pressure and temperature are known, the proposed method enables a complete thermodynamic description of vapor clouds, thereby serving as a powerful tool in investigating the thermodynamic and chemical properties of impact‐ and laser‐induced vapor clouds.
Morphodynamics of subaqueous levee formation: Insights into river mouth morphologies arising from experiments
Authors: Rowland Joel C. , Dietrich William E. , Stacey Mark T.
Published: October 2010

Levee formation by deposition from sediment‐laden flows debouching into open waters has been conceptually and analytically linked to jet hydrodynamics since the middle of the 20th century. Despite this long‐standing association between jets and levees, the morphodynamics controlling subaqueous levee development remain largely unquantified and poorly understood. Here we report the results of physical experiments on subaqueous levee development modeled on floodplain tie channel processes. In the laboratory, we created subaqueous levees from a sediment‐laden jet entering a basin of still water. Levee formation occurred where the local shear velocity of the jet declined below the critical shear velocity for entrainment of sediment into suspension. The rate of levee deposition depended on the rate of lateral sediment transfer to the jet margins and the settling velocity of suspended sediment. In our friction‐dominated flows, lateral sediment flux to the levees was primarily due to dispersive lateral transport driven by turbulence. High rates of sediment transfer from the jet core to the margins led to levee growth that outpaced deposition along the flow centerline. Under hypopycnal conditions, we failed to produce levees. We observed distinct differences in levee morphology due to changes in the size and density of suspended sediment under identical hydrodynamic conditions. Our experimental results and review of published data on hypopycnal river mouths suggest that suspended sediment characteristics, relative magnitude of bed friction, and channel outlet aspect ratios may have a more significant influence on river mouth morphology than the buoyancy of discharging waters as envisioned in existing conceptual models.
Variable composition of particle‐bound organic carbon in steepland river systems
Authors: Gomez Basil , Baisden W. Troy , Rogers Karyne M.
Published: October 2010

The reported range (<10% to >90%) of modern particulate organic carbon (POC) in the suspended load of steepland rivers is at odds with the opinion that this class of river is an important source of ancient organic carbon. Analysis of all available data shows the composition of POC transported by steepland rivers is fundamentally determined by the relative contributions made by shallow hillslope erosion processes that mobilize soil‐derived modern organic carbon and deep‐seated erosion processes that release bedrock‐derived ancient organic carbon. Attribution of sources during a flood with a return period of >20 years in the Waipaoa River basin, New Zealand, serves to emphasize that by no means all of the POC originating from high‐yield steepland drainage basins is derived from sedimentary rocks. POC in the Waipaoa River is expected to be 14C‐depleted because gully erosion into bedrock ordinarily regulates suspended sediment yield across the entire range of flows. However, during this event the topsoil contribution was more important, ranging from 56% ± 9% on the rising limb to 16% ± 5% on the falling limb of the flood hydrograph and modern organic carbon accounted for 71% of the total POC yield. The amount of ancient organic carbon may be overestimated if the contribution topsoil makes to POC yield across the flood hydrograph is underestimated. Furthermore, to quantify the contribution made by different sources of organic matter in steepland drainage basins, it is necessary to consider the time‐varying signatures and relative contributions each erosion process makes to event POC yields.
Aromatic chloride to nitrile transformation: medicinal and synthetic chemistry
Authors: Jones Lyn H. , Summerhill Nicholas W. , Swain Nigel A. , Mills James E.
Published: October 2010

This review highlights the medicinal and synthetic chemistry relevance of replacing an aromatic chloride motif with an aromatic nitrile.
Energy surface, chemical potentials, Kohn–Sham energies in spin-polarized density functional theory
Authors: Gál T. , Geerlings P.
Published: October 2010

On the basis of the zero-temperature grand canonical ensemble generalization of the energy E[N,Ns,v,B] for fractional particle N and spin Ns numbers, the energy surface over the (N,Ns) plane is displayed and analyzed in the case of homogeneous external magnetic fields B(r⃑). The (negative of the) left-/right-side derivatives of the energy with respect to N, N↑, and N↓ give the fixed-Ns, spin-up, and spin-down ionization potentials/electron affinities, respectively, while the derivative of E[N,Ns,v,B] with respect to Ns gives the (signed) half excitation energy to the lowest-lying state with Ns increased (or decreased) by 2. The highest occupied and lowest unoccupied Kohn–Sham spin-orbital energies are identified as the corresponding spin-up and spin-down ionization potentials and electron affinities. The excitation energies to the lowest-lying states with Ns±2 can be obtained as the differences between the lowest unoccupied and the opposite-spin highest occupied spin-orbital energies, if the (N,Ns) representation of the Kohn–Sham spin-potentials is used. The cases where the convexity condition on the energy does not hold are also discussed. Finally, the discontinuities of the energy derivatives and the Kohn–Sham potential are analyzed and related.
A simultaneous multiple-section photoacoustic imaging technique based on acoustic lens
Authors: Chen Xian , Tang Zhilie , He Yongheng , Liu Haifeng , Wu Yongbo
Published: October 2010

In this paper, we propose a simultaneous multiple-slice photoacoustic (PA) imaging technique by utilizing an acoustic lens with parallel imaging ability. Our method can directly image multiple slices of the three-dimensional (3D) PA images in real-time without utilizing special reconstruction algorithms. Combining the advantages of an acoustic lens with long focal depth and a fast data acquisition system with high sampling rate, the new system can acquire all slices of a 3D object simultaneously. This is achieved by utilizing the time-resolved technique that allows to distinguish PA signals from different object planes. According to the experiment results, the reconstructed sectional images match the original samples well. The proposed technique provides a fast and reliable approach to multiple-section PA imaging. Our study can be applied to noninvasive imaging and medical diagnosis.
Quantum U-statistics
Authors: Guţă Mădălin , Butucea Cristina
Published: October 2010

The notion of a U-statistic for an n-tuple of identical quantum systems is introduced in analogy to the classical (commutative) case: given a self-adjoint “kernel” K acting on (Cd)⊗r with r<n, we define the symmetric operator Un=(nr)∑βK(β) with K(β) being the kernel acting on the subset β of {1,…,n}. If the systems are prepared in the product state ρ⊗n, it is shown that the sequence of properly normalized U-statistics converges in moments to a linear combination of Hermite polynomials in canonical variables of a canonical commutation relation algebra defined through the quantum central limit theorem. In the special cases of nondegenerate kernels and kernels of order of 2, it is shown that the convergence holds in the stronger distribution sense. Two types of applications in quantum statistics are described: testing beyond the two simple hypotheses scenario and quantum metrology with interacting Hamiltonians.