bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Characterization of the Tetraphosphonic Acid Ester (Et2O3PCH2)4C6H2 and the Open‐Framework Cadmium Tetraphosphonate, Cd2[(HO3PCH2)4C6H2]
Authors: Stock Norbert , Guillou Nathalie , Senker Jürgen , Férey Gérard , Bein Thomas
Published: February 2005

Following the strategy of using polyfunctional phosphonic acids for the synthesis of open‐framework metal phosphonates, the ethyl ester of a tetraphosphonic acid, i. e. (Et2O3PCH2)4C6H2 (1) was synthesized and used in the hydrothermal synthesis of the new cadmium tetraphosphonate, Cd2[(HO3PCH2)4C6H2] (2). The structure of 1 was solved from single crystal data (1: triclinic, P1¯, a = 12.3846(2), b = 12.6166(3), c = 12.9915(3) Å, α = 86.380(1), β = 63.372(1), γ = 89.589(1)°, V = 1810.51(7) Å3, Z = 2, R1 = 0.077, wR2 = 0.177). The in situ hydrolysis of the ethyl ester and the reaction with the Cd2+ ions leads to the well‐crystallized microcrystalline product 2. Its structure was solved and refined using X‐ray powder diffraction data (2: triclinic, P1¯, with a = 11.0435(5), b = 7.5809(3), c = 5.4250(2) Å, α = 98.354(2), β = 101.951(2), γ = 95.885(3)°, V = 435.48(9) Å3, Z = 1, Rwp = 0.096, Rp = 0.072, RB = 0.081, RF = 0.069). Whereas the structure of 1 is a molecular structure, the structure of Cd2[(HO3PCH2)4C6H2] (2) is built up from edge sharing CdO6 octahedra forming dimeric [Cd2O10] polyhedra. In the second coordination sphere of each of the CdII ions six HO3PCH2R units are observed. The [Cd2O10] polyhedra are connected to six other [Cd2O10] polyhedra by ten hydrogenphosphonic acid units. Thus inorganic sheets are formed that are connected to a three‐dimensional framework with small channels, through the phenyl rings. Thermogravimetric as well as IR‐, 113Cd‐MAS‐NMR and 31P‐MAS‐NMR data are also presented.
[C3H7N(C2H4)3NC3H7]2 ∞1[Sn4I12] ‐ Ein Iodostannat aus verknüpftenSnI5‐Pyramiden
Authors: Lode Christine , Krautscheid Harald , Müller Ulrich
Published: February 2005

Bei der Reaktion von SnI2 mit [C3H7N(C2H4)3NC3H7](PF6)2 in DMF entsteht das Iodostannat [C3H7N(C2H4)3NC3H7]2[Sn4I12] (1), das eine neuartige Anionenstruktur aufweist. Gemeinsame Iodoliganden verknüpfen SnI3‐‐Einheiten zu polymeren Strängen von eckenverknüpften SnI5‐Pyramiden. Nach der Röntgenstrukturanalyse kristallisiert 1 in der Raumgruppe Pna21 mit a = 3948, 6(4), b = 916, 7(1), c = 2914, 3(3) pm und acht Formeleinheiten pro Elementarzelle. Die Kristallstruktur weist eine ausgeprägte Pseudosymmetrie auf, indem die Symmetrie der Raumgruppe Pnmn mit halbiertem Gitterparameter a näherungsweise erfüllt ist. Da Pnmn eine Obergruppe von Pna21 ist, könnte es bei höherer Temperatur eine Phasenumwandlung zweiter Ordnung geben. In der vermuteten Hochtemperaturform in der Raumgruppe Pnmn müßten die C‐Atome mit halbbesetzten Atomlagen fehlgeordnet sein.
DFT‐Investigations of Pentatomic Cobalt Selenide Clusters [(CpRCo)3(μ3‐Se)2]q (CpR = Cp, Cp*; q = 2+, 1+, 0, 1‐)
Authors: Dehnen Stefanie
Published: February 2005

Density functional theoretical (DFT) investigations were performed to get insight in the terminal ligands' influence on the structures of pentatomic, Cp or Cp* coated cobalt selenide clusters [(CpRCo)3(μ3‐Se)2]q (CpR = Cp, Cp*; q = 2+, 1+, 0, 1‐, referring to 48, 49, 50, 51 valence electrons; Cp* = pentamethyl‐Cp; Cp = cyclopentadienyl). The calculations reveal that for clusters with 48, 49, or 51 valence electrons, only structures with a trigonal bipyramidal Co3Se2 core (closo) represent local minima on the energy hyperface; in contrast, the 50 electron clusters can be calculated in two isomeric minimum structures each, one according to a distorted trigonal bipyramid (closo), and one with a square pyramidal core (nido). The 50 electron closo structure ‐ which disagrees with Wade‐Mingos rules ‐ was shown to be energetically preferred compared to the nido‐type Co3Se2 cage as soon as bulky ligands such as Cp* enforce a distinct enlargement of interatomic distances within the cluster core. This may explain the experimentally observed “anti‐Wade‐Mingos” structures of respective compounds like [(Cp*Co)3(μ3‐Se)2] (1).
Global interplay and irony
Authors: McArthur Tom
Published: February 2005

In recent times ET has received many articles on English in China, and published as many as feasible, but the sheer volume has led to a strangely serious question: How many such articles can we publish without ET becoming English in China Today? Inevitably, therefore, we have been publishing only some of the publishable submissions received. It is therefore ironic to bring out the cover article for this issue, whose subject matter looks Chinese but is about something happening to English outside China. The article is not about English in China or Chinese in a world dominated by English, but describes the work of a Chinese artist in effect playing Sinocentric games with the global language.
Xu Bing: calligraphy, language and interpretation
Authors: CHATTOPADHYAY COLLETTE
Published: February 2005

Radical departures in English in the work of a Chinese calligrapher. Challenging conventional assumptions regarding the use of language, Xu Bing's calligraphic artworks of the early 1990s address the English-speaking world from a space deep within the bedrock of Chinese culture. Ironically extending and querying the continued relevance of the Chinese calligraphic tradition in a post-Mao, post-modern, trans-cultural era, Xu's New English Calligraphy cloaks English words in Chinese form. Exploring the communicative functions of language, these works examine the relation between linguistic intent and subsequent understanding or misunderstanding.
‘Never perfectly printed’: the Authorized Version of the Bible
Authors: NORTON DAVID
Published: February 2005

The text is the editor's introduction to The New Cambridge Paragraph Bible to be published in 2004.

THOUGH it is the most important book in the religious life and the culture of the English-speaking world, the King James Bible or Authorised Version of 1611 has never been perfectly printed. This is not to say either that it is badly printed or that absolute perfection can be achieved, but that the text and its presentation can be improved. First, what we now read as the King James Bible contains numerous deliberate and some accidental changes to the text, and these can be revised to make it more faithful to the King James translators' own decisions as to how it should read. Second, the presentation of the text – spelling, punctuation and formatting – interferes with the clarity with which it speaks to the minds and souls of present-day readers. Unnecessary background noise gets in the way. To use another image, there is dust and dirt on the old master, the paint is darkened and cracked: we can still see that the picture is a great one, but not how great it is. This article continues to explore the criteria used behind the publication of this new work.
Baths and becks
Authors: GUPTA ANTHEA FRASER
Published: February 2005

A report on two prominent dialectal variables in England. Using rather informally collected data, The author looks here at two well-known variables in the English of England: first, whether there is a short or long vowel in words such as grass and bath; second, what regional words people know for streams. The treatment of these variables is consistent over time, and seems to have little to do with social status or carefulness of speech.
Butler English
Authors: HOSALI PRIYA
Published: February 2005

An account of a highly distinctive variety of English in India. When the British set up colonies worldwide they brought with them a legacy that included their language, which many of the natives accepted and acculturated: it would after all be unreasonable to expect an imperial language to function in a vacuum with no local nuances. Indeed, gradual acculturation produced a number of varieties of English used as second languages. In their almost 200 years of not-so-peaceful stay on the subcontinent, the British and many Indians used English, fulfilling in at least a linguistic sense Macaulay's dream of an ‘imperishable empire’. In these 200 years, English in India slowly went through a process now labelled Indianization, evolving into the variety (or group of varieties) called Indian English. One subvariety, generally referred to as Butler English, though by no means confined to butlers, is described and discussed here.
The many names of English
Authors: ERLING ELIZABETH J.
Published: February 2005

A discussion of the variety of labels given to the language in its worldwide role. In his article ‘Is it world or international or global English, and does it matter?’ (ET79, Jul 04), Tom McArthur welcomes further comment on the names of English in a ‘globalizing world’. He examines the histories and meanings of the three most popular labels for English: world, international and global. In addition to discussing his contribution, I would like to draw attention to other, perhaps less familiar names for English that have been proposed as alternatives. This paper seeks both to survey these labels and uncover why there is such a strong compulsion to rename the language. I suggest that these proposals have arisen in response to postcolonial ambiguity about the spread of English and a desire to shape a new ideology for English language teaching (ELT) which more accurately reflects the global nature of the language and its diverse uses and users.
Intellectual franglais
Authors: BULLEY MICHAEL
Published: February 2005

Some adjectival links across the Channel. Of the countless delights and complexities to be discovered in the relationships among the Indo-European languages, particularly fascinating are the connections between English and French. The two languages start together in proto-Indo-European (if there ever was such a thing), diverge into the Germanic and Latinate branches of the family, come together (north of the channel only) with the merging of French and English after the invasion of William of Normandy in 1066, and have been glued together even more by the influence of the classical languages, particularly Latin, in and after the Renaissance.
Lacking consonance?
Authors: DAVIDSON KEITH
Published: February 2005

Puzzled by Michael Bulley's ‘Consonantal beginnings’, in ET80 (Oct 04) who does admit to some difficulty in discussing initial consonant clusters in English, when he says: ‘The conventions of writing can mislead us about speech.’ While the restoration of the phonetic symbols in the ‘full and proper form’ of the article (ET80) now elucidates some of the puzzles in the previous version (ET79), difficulties remain in maintaining a clear distinction between the sound systems of English and the writing system.
The first English learner's dictionary: the Chinese dimension
Authors: McARTHUR TOM
Published: February 2005

Reflections on the Oxford Advanced Learner's English-Chinese Dictionary and its mother book, the Oxford Advanced Learner's Dictionary.
Ultrastructural observations of previtellogenic ovarian follicles of dove
Authors: Zarnescu Otilia
Published: February 2005

Dove ovarian follicle is a complex structure composed of oocyte surrounded by a somatic compartment consisting of theca externa, theca interna and granulosa. The structure of ovarian follicle (1 and 2 mm) of dove was studied by electron microscopy. The granulosa was pseudostratified in the 1-mm-diameter follicles and stratified with two or three irregular rows of cells in the 2-mm-diameter follicles. In the larger follicle indentations between oocyte and granulosa cells become more numerous and the microvilli of granulosa cell elongated to form a zona radiata with similarly elongated oocyte microvilli. Lining bodies were present at the tips of granulosa microvilli and in the cortical region of the oocyte. In the oocyte cortex were observed coated pits, coated vesicles, dense tubules, multivesicular bodies and primordial yolk spheres. Primordial yolk spheres may contain lining bodies and were observed fused with dense tubules and multivesicular bodies or associated with smooth cisternae.
Effects of melatonin treatment on Leydig cell activity in the testis of the frog Rana esculenta
Authors: d'Istria Michela , Serino Ismene , Izzo Gaia , Ferrara Diana , De Rienzo Gianluca , Minucci Sergio
Published: February 2005

This study was conducted to verify the effect(s) of melatonin treatment on frog Leydig cells. Morphological observation after melatonin treatment indicates that many frog Leydig cells show degenerative changes (i.e. heterochromatic nuclei, loss of cellular adhesion) while in adjacent germinal tubules several Sertoli cells show heterochromatic nuclei, confirming the presence of a paracrine effect between interstitial and germinal compartments. The effect of melatonin on frog Leydig cell steroidogenesis was investigated in in vitro experiments; after 6 h of incubation melatonin severely inhibits both control and GnRH-induced testosterone secretion. In addition, in order to verify the effect of indolamine on frog Leydig cell activity, we investigated, by in situ hybridization, the presence of frog relaxin (fRLX, a transcript specifically expressed by these cells) in the testes of melatonin-injected animals after 48 h. fRLX signal completely disappeared from the testis of melatonin-injected frogs. The results of the present study indicate that melatonin treatment provokes Leydig cell morphological changes, blocks GnRH-antagonist-induced testosterone secretion and decreases fRLX expression. Taken together these results strongly indicate that melatonin acts on Leydig cells in the testis of the frog Rana esculenta.
Effects of cryodevice type and donors' sexual maturity on vitrification of minke whale (Balaenoptera bonaerensis) oocytes at germinal vesicle stage
Authors: Iwayama Hiroshi , Hochi Shinichi , Kato Megumi , Hirabayashi Masumi , Kuwayama Masashige , Ishikawa Hajime , Ohsumi Seiji , Fukui Yutaka
Published: February 2005

Germinal-vesicle-stage oocytes enclosed with compact cumulus cell layers (COCs) were recovered from adult or prepubertal minke whale ovaries, and were vitrified in a solution containing 15% ethylene glycol, 15% DMSO and 0.5 M sucrose using either a Cryotop or an open-pulled straw (OPS) as the cryodevice. The post-warm COCs with normal morphology were cultured for 40 h in a 390 mosmol in vitro maturation medium, and oocytes extruding the first polar body were considered to be matured. The proportion of morphologically normal COCs after vitrification and warming was higher when the COCs were cryopreserved by Cryotop (adult origin, 88.4%; prepubertal origin, 80.8%) compared with the OPS (adult origin, 67.7%; prepubertal origin, 64.2%). The oocyte maturation rate was higher in the adult/Cryotop group (29.1%) compared with those of the prepubertal/Cryotop group (14.4%), the adult/OPS group (14.3%) and the prepubertal/OPS group (10.6%). These results indicate that the Cryotop is a better device than the OPS for vitrification of immature oocytes from adult minke whales.
Ovarian response in sheep superovulated after pretreatment with growth hormone and GnRH antagonists is weakened by failures in oocyte maturation
Authors: Gonzalez-Añover Pedro , Encinas Teresa , Garcia-Garcia Rosa M. , Veiga-Lopez Almudena , Cocero Maria J. , McNeilly Alan S. , Gonzalez-Bulnes Antonio
Published: February 2005

The administration of growth hormone (GH) or GH plus GnRH antagonists (GnRHa) in sheep allows the enhancement of the pool of gonadotrophin-responsive follicles present in the ovaries and may be useful to increase yields obtained in embryo programmes. The objective of the current study was to evaluate the ability of follicles recruited in response to treatment with GH and GnRHa to grow in response to exogenous follicle stimulating hormone (FSH) and the competence of their oocytes to resume meiosis. Seven females were treated with two doses of GnRHa (days 0 and 3) and three doses of 15 mg of GH (days 3, 4 and 5). Thereafter, this group and a second group (n=7) were treated with three doses of 1.5 ml of FSH 12 h apart. A third group (control; n=4) did not receive GH/GnRHa or FSH. The mean number of follicles aspirated on day 7 was higher in ewes treated with GH and GnRHa prior to the stimulation with exogenous FSH than in ewes treated with FSH without pretreatment and in untreated control sheep (20.4 ± 2.6 vs 17.7 ± 3.9 and 11.5 ± 0.8, p < 0.05 and p < 0.01, respectively). The number of recovered cumulus–oocyte complexes after follicular aspiration was higher in the GH/GnRHa+FSH group (8.7 ± 0.9 vs 6.8 ± 1.3 in FSH group, n.s., and 4.5 ± 0.8 in control, p < 0.05), but there were no differences found in the resumption of meiosis (63.1 ± 9.5% for GH/GnRHa + FSH vs 79.5 ± 6.3% for FSH and 60.0 ± 8.8% for control). These results indicate that GH and GnRHa would be useful to increase the number of gonadotrophin-responsive follicles in the ovary, but adjustment of later FSH treatment allowing further development of follicles may be necessary prior to its use in superovulatory protocols.
Chromosomal analysis of mouse spermatozoa following physical and chemical treatments that are effective in inactivating HIV
Authors: Morozumi Kazuto , Tateno Hiroyuki , Yanagida Kaoru , Katayose Haruo , Kamiguchi Yujiroh , Sato Akira
Published: February 2005

Human immunodeficiency virus (HIV) can be inactivated by heating at 56 °C for 30 min, treating with 50% ethanol at room temperature for 10 min, or treating with 2% sodium hypochlorite solution (NaClO) at room temperature for 60 min. Using a mouse model, we evaluated the risk of generating chromosome damage in spermatozoa following these treatments. The spermatozoa were all dead after the treatments. Although 41.3% of oocytes injected with ethanol-treated spermatozoa successfully activated, none of the oocytes injected with heated or NaClO-treated spermatozoa activated. When artificial stimulation with strontium was used, the fertilization of oocytes with heated or ethanol-treated spermatozoa was completely rescued. Sperm nuclei treated with NaClO neither decondensed nor developed to a male pronucleus. The incidences of structural chromosome aberrations in 1-cell zygotes derived from the heated spermatozoa (45.6%) and ethanol-treated spermatozoa (91.2%) were significantly higher than those in the matched controls (5.5% and 10.5%, respectively). Further study is needed to develop a methodology for the protection of spermatozoa against chromosome damage or the separation of damaged spermatozoa before intracytoplasmic sperm injection.
Sea‐ice melting processes inferred from ice–upper ocean relationships in the Ross Sea, Antarctica
Authors: Nihashi Sohey , Ohshima Kay I. , Jeffries Martin O. , Kawamura Toshiyuki
Published: February 2005

Sea‐ice melting processes are inferred from various summer sea‐ice and upper ocean data obtained in the Ross Sea in January 1999. Using spatially (30 km) averaged continuous data, an ice concentration–water temperature plot (CT‐plot) shows that the temperature at a depth of ∼7 m increases as ice concentration decreases in the ice interior region. The CT‐plot is explained by a simple ice–upper ocean coupled model in which sea‐ice melting is caused only by heat input through open water. The bulk heat transfer coefficient between ice and ocean (Kb) is estimated to be 1.2 × 10−4 m s−1. These findings are supported by the relationship between ice concentration and heat content in the mixed layer estimated from conductivity‐temperature‐depth (CTD) data. Salinity at a depth of ∼7 m, salt deficit in the mixed layer associated with sea‐ice melt estimated from CTD data, and their relationships with ice concentration also suggest that melting is mainly caused by atmospheric heat input through open water and that local balance of salinity nearly hold. The time evolution of ice concentration calculated from the ice–upper ocean coupled model with the estimated Kb corresponds with that derived from the Special Sensor Microwave Imager (SSM/I), confirming the model's applicability and the value of Kb.
Nitrogen transport and transformations in a coastal plain watershed: Influence of geomorphology on flow paths and residence times
Authors: Tesoriero Anthony J. , Spruill Timothy B. , Mew H. E. , Farrell Kathleen M. , Harden Stephen L.
Published: February 2005

Nitrogen transport and groundwater‐surface water interactions were examined in a coastal plain watershed in the southeastern United States. Groundwater age dates, calculated using chlorofluorocarbon and tritium concentrations, along with concentrations of nitrogen species and other redox‐active constituents, were used to evaluate the fate and transport of nitrate. Nitrate is stable only in recently recharged (<10 years) water found in the upper few meters of saturated thickness in the upland portion of a surficial aquifer. Groundwater with a residence time between 10 and 30 years typically has low nitrate and elevated excess N2 concentrations, indications that denitrification has reduced nitrate concentrations. Groundwater older than 30 years also has low nitrate concentrations but contains little or no excess N2, suggesting that this water did not contain elevated concentrations of nitrate along its flow path. Nitrate transport to streams varies between first‐ and third‐order streams. Hydrologic, lithologic, and chemical data suggest that the surficial aquifer is the dominant source of flow and nitrate to a first‐order stream. Iron‐reducing conditions occur in groundwater samples from the bed and banks of the first‐order stream, suggesting that direct groundwater discharge is denitrified prior to entering the stream. However, nitrogen from the surficial aquifer is transported directly to the stream via a tile drain that bypasses these reduced zones. In the alluvial valley of a third‐order stream the erosion of a confining layer creates a much thicker unconfined alluvial aquifer with larger zones of nitrate stability. Age dating and chemical information (SiO2, Na/K ratios) suggest that water in the alluvial aquifer is derived from short flow paths through the riparian zone and/or from adjacent streams during high‐discharge periods.
Entropy budget of the ocean system
Authors: Yan Youfang , Gan Zijun , Qi Yiquan
Published: February 2005

An entropy balance equation including the transfers of heat and mass, work of external force of the ocean is presented and discussed. Entropy flux through the sea surface are calculated, and the results show that entropy flux due to heat transfer is about −555.6 mWm−2K−1, entropy flux connected with the work of wind stress is relatively smaller at about −0.09 mWm−2K−1, entropy flux due to mass transfer is −0.02 mWm−2K−1, the sum of all the entropy flux is −555.7 mWm−2K−1, the mean rate of generation of entropy inside the ocean must be 555.7 mWm−2K−1 when the ocean is in a climatic steady condition.
On the relationship between Tibetan snow cover, the Tibetan plateau monsoon and the Indian summer monsoon
Authors: Zhao Hongxu , Moore G. W. K.
Published: February 2005

More than a century ago, Blanford suggested that an inverse relationship existed between summer rainfall over Northwest India and snow cover in the western Himalaya. Recently it has been found that there is a positive correlation between Tibetan snow cover and Indian summer monsoon rainfall (IMR), a result opposite to that of Blanford. In this paper, we attempt to reconcile these contradictory observations through the analysis of spatial and temporal variability of Tibetan snow cover and its relationship with the Indian summer monsoon. We show that there exists an east‐west dipole‐like correlation pattern between snow cover over the Tibetan plateau and IMR that underwent a change in sign around 1985. We argue that variability in the Tibetan plateau monsoon is responsible for the spatial and temporal variability in the relationship between Tibetan snow cover and the Indian summer monsoon.
Observed north‐south asymmetries in the long‐term Bz mean average
Authors: Keating C. F. , Jager N. O.
Published: February 2005

Several publications have reported a north‐south asymmetry of the solar magnetic polarity in variations of the solar wind, geomagnetic activity, and polar coronal holes. The present study analyzes the polarity of the z‐component of the interplanetary magnetic field (IMF Bz), finding long‐term periods with a predominant polarity. IMF data was averaged using a 13‐month ‘boxcar’ long‐term averaging method that has been used to smooth the sunspot number for use in the McNish‐Lincoln forecasting method. Both the averaging technique and the McNish‐Lincoln forecasting method have also been used to forecast the average magnitude of Bz. However, this previous work did not examine the effect of polarity. The work reported here used the same averaging method to examine the long‐term average of Bz, but also considered the polarity. The resulting averages for the period 1963–2002 showed long periods where one polarity dominated the other. Examination of the data has led us to believe this predominance is caused by a shift of the heliomagnetic equator away from the heliographic equator.
Global storm time plasma redistribution imaged from the ground and space
Authors: Immel Thomas J. , Foster John C. , Coster Anthea J. , Mende Stephen B. , Frey Harold U.
Published: February 2005

The bulk redistribution of plasma in the near‐Earth space environment during the onset and main phase of a magnetic storm has been observed on a global scale with 2‐minute resolution using Far‐Ultraviolet images from the NASA‐IMAGE satellite and ground‐based total electron content (TEC) maps using Global Positioning Satellite (GPS) receivers. The dynamic variations under the storm conditions show a redistribution of plasma away from the nominal low‐latitude location of the equatorial ionospheric anomalies, resulting in peak nightside ionospheric densities at middle latitudes. A zonal redistribution of plasma is also evident, as the plasma is depleted across the Atlantic sector, while TEC values grow in the Caribbean sector to the largest values on the nightside. The ground‐based GPS measurements provide 24‐hour observations of TEC, while the FUV measurements provide nightside observation with greater spatial resolution, continuous over land and sea. The complimentary observations are shown to have a very good correspondence, promising new analyses of storm time plasma redistribution with high temporal and spatial resolution and greatly improved global coverage.
Halocline structure in the Canada Basin of the Arctic Ocean
Authors: Shimada Koji , Itoh Motoyo , Nishino Shigeto , McLaughlin Fiona , Carmack Eddy , Proshutinsky Andrey
Published: February 2005

We examine the varieties and spatial distributions of Pacific and Eastern Arctic origin halocline waters in the Canada Basin using 2002–2003 hydrographic data. The halocline structure in the Canada Basin is different from the Eastern Arctic halocline because it includes fresher Pacific Winter Waters that form a “cold halostad” which lies above the Eastern Arctic origin lower halocline waters. The structure of the halostad in the Canada Basin, however, is not spatially uniform, and depends on the pathway and history of the source water. Pacific Winter Water entering through the Bering Strait becomes salty due to sea ice formation and this, in turn, is dependent on the occurrence and distribution of polynyas. In particular, saline water from the eastern Chukchi Sea forms thick halostad and causes depression of the isohalines in the southern Canada Basin. This depression influences thermohaline structure of the oceanic Beaufort Gyre.
Evidence for subglacial water transport in the West Antarctic Ice Sheet through three‐dimensional satellite radar interferometry
Authors: Gray Laurence , Joughin Ian , Tulaczyk Slawek , Spikes Vandy Blue , Bindschadler Robert , Jezek Ken
Published: February 2005

RADARSAT data from the 1997 Antarctic Mapping Mission are used interferometrically to solve for the 3‐dimensional surface ice motion in the interior of the West Antarctic Ice Sheet (WAIS). An area of ∼125 km2 in a tributary of the Kamb Ice Stream slumped vertically downwards by up to ∼50 cm between September 26 and October 18, 1997. Areas in the Bindschadler Ice Stream also exhibited comparable upward and downward surface displacements. As the uplift and subsidence features correspond to sites at which the basal water apparently experiences a hydraulic potential well, we suggest transient movement of pockets of subglacial water as the most likely cause for the vertical surface displacements. These results, and related lidar observations, imply that imaging the change in ice surface elevation can help reveal the key role of water in the difficult‐to‐observe subglacial environment, and its important influence on ice dynamics.
Hurricane forecasting with the high‐resolution NASA finite volume general circulation model
Authors: Atlas R. , Reale O. , Shen B.‐W. , Lin S.‐J. , Chern J.‐D. , Putman W. , Lee T. , Yeh K.‐S. , Bosilovich M. , Radakovich J.
Published: February 2005

A high‐resolution finite volume general circulation model (fvGCM), resulting from a development effort of more than ten years, is now being run operationally at the NASA Goddard Space Flight Center and Ames Research Center. The model is based on a finite volume dynamical core with terrain‐following Lagrangian control volume discretization and performs efficiently on massive parallel architectures. The computational efficiency allows simulations at a resolution of a quarter of a degree, which is double the resolution currently adopted by most global models in operational weather centers. Such fine global resolution brings us closer to overcoming a fundamental barrier in global atmospheric modeling for both weather and climate, because tropical cyclones can be more realistically represented. In this work, preliminary results are shown. Fifteen simulations of four Atlantic tropical cyclones in 2002 and 2004, chosen because of varied difficulties presented to numerical weather forecasting, are performed. The fvGCM produces very good forecasts of these tropical systems, adequately resolving problems like erratic track, abrupt recurvature, intense extratropical transition, multiple landfall and reintensification, and interaction among vortices.
Forecasting lava flow paths by a stochastic approach
Authors: Favalli Massimiliano , Pareschi Maria Teresa , Neri Augusto , Isola Ilaria
Published: February 2005

A stochastic model, named DOWNFLOW, is presented to forecast possible lava flow paths with the aim of hazard assessment and mitigation. The model relies on the fact that lava flow emplacement is, in many cases, controlled by topography. The potential inundation area of the flow is determined by considering a number of steepest paths over stochastic perturbations of the original topography. Since the code requires very short computational time and few input data the model proved to be a very useful tool to obtain real‐time predictions during the initial phase of an eruption. The necessary topographic information can be obtained by photogrammetry, radar altimetry, or laser scanning techniques. DOWNFLOW has been successfully applied to a number of flows, including the September 2004 lava flow, where updated topographies were available.
Attenuation measurements from sonic waveform logs in methane hydrate‐bearing sediments at the Nankai Trough exploratory well off Tokai, central Japan
Authors: Matsushima Jun
Published: February 2005

I have used full waveform logs from the Nankai Trough exploratory well off central Japan to estimate both compressional and shear attenuation in sediments containing methane hydrate (MH). The attenuation estimates are based on a median frequency shift to the amplitude spectrum of the recorded waveforms. This paper is concerned with attenuation at sonic frequencies of 10–20 kHz for compressional waves and 500–1000 Hz for shear waves. I observed that the presence of MH increases the host sediments' seismic attenuation, and shear attenuation may be more helpful than compressional attenuation in detecting or characterizing MH‐bearing sediments as compressional attenuation is affected by the presence of gas. Moreover, the ratio of compressional to shear attenuation is found to be a more sensitive indicator of the presence of low‐saturation gas than the corresponding velocity ratio.
Trace gas emissions through a winter snowpack in the subalpine ecosystem at Niwot Ridge, Colorado
Authors: Swanson Aaron L. , Lefer Barry L. , Stroud Verity , Atlas Elliot
Published: February 2005

A preliminary study of whole air measurements within a snowpack in the subalpine forest of Colorado found that lower snow layers and underlying soil were a strong source of chemically active trace gases (VOC). The emissions of trace gases were correlated with emissions of radiatively active greenhouse gases (CO2 and N2O) through the snowpack. Carbon dioxide was enhanced in the lower snowpack to over 1000 ppmv, similar to previous studies, which have shown that a thermal insulation of snow covering the soil leads to enhanced emissions of CO2 equivalent to a large fraction of annual respiration. Comparable enhancements of several VOCs reached 1275, 1670, and 1000 pptv for methyl chloride, propane, and α‐pinene, respectively. The measurements are limited to a one‐day pilot study, however, considering that previous studies have reported significant CO2 emissions through snowpacks any emissions of VOC may also be important on a local or potentially global scale.
How typical are atypical current sheets?
Authors: Asano Y. , Nakamura R. , Baumjohann W. , Runov A. , Vörös Z. , Volwerk M. , Zhang T. L. , Balogh A. , Klecker B. , Rème H.
Published: February 2005

Using multi‐satellite Cluster magnetic field data, we statistically examined how often an atypical, i.e., non‐Harris type, current sheet is formed. We found that a cross‐tail current sheet with an off‐equatorial current density maximum, indicating bifurcation, is frequently formed in thin current sheets with a half thickness of ∼1500 km. The occurrence of off‐equatorial current density maxima is correlated with the occurrence of fast plasma flows, namely if fast plasma flows occur nearby, one is more likely to observe off‐equatorial current density maxima. We also found that many of the center‐peaked current sheets exhibit a feature different from a normal Harris sheet: namely a very intense current concentrated near the equatorial plane, embedded in a broader current sheet with lower current density.
Nonlinear analysis of the geometry of meandering rivers
Authors: Perucca Eliana , Camporeale Carlo , Ridolfi Luca
Published: February 2005

The geometry of four meandering rivers has been investigated to detect linear and nonlinear links in their planimetry. To this aim, some robust nonlinearity tests—DVS plots, reversibility tests, and the Kaplan test—have been applied to the spatial series of local curvatures. The results are coherent and show that no relevant nonlinearities seem to be detectable in the analyzed meandering river patterns. From a river dynamics point of view, this can be explained by the occurrence of meander cutoffs and external forcing which prevent nonlinear morphodynamic processes from significantly influencing the long‐term meandering dynamics and, consequently, the river geometry.
Characteristics of electromagnetic Rayleigh‐Taylor modes in nighttime equatorial plasma
Authors: Basu B.
Published: February 2005

The unstable Rayleigh‐Taylor plasma modes that are believed to be responsible for the density irregularities in the nighttime F region equatorial ionosphere have been studied before by assuming that the modes are electrostatic. In this paper, these plasma modes are studied without such assumption in order to determine the strength and the characteristics of the magnetic field fluctuations and to determine the physical condition under which the electrostatic assumption is justified. It is found that the relevant magnetic field fluctuations (ρ), which arise from the fluctuating parallel (to B0) current density, are associated with the shear Alfven waves. The parameter that determines the amplitude of ρ is α(s) ≡ Dm(s)k��2/γ, where Dmk��2 represents the rate at which magnetic field fluctuations with perpendicular wavelength λ��(≡ 2π/k��) diffuse away due to parallel resistivity and γ is the rate at which the fluctuations grow. Typically, α ≫ 1 in the equatorial ionosphere, which means that the excited magnetic field fluctuations diffuse at a rate much faster than their growth rate and, consequently, their amplitudes remain very small (compared to B0). Thus the Rayleigh‐Taylor modes in the equatorial ionosphere are predominantly electrostatic in nature, and the electrostatic assumption of the previous analyses is quite justified. If the maximum amplitude of the electric field fluctuations (��) is taken to be 1 mV/m, then the maximum amplitude of ρ is found to be less than 0.2 nT when λ�� is 500 m, and it increases to about 2.4 nT when λ�� is 20 km. Longer wavelength modes have somewhat larger magnetic field fluctuations, but their growth rates are smaller. While the maximum amplitude of �� occurs at the magnetic equator, that of ρ occurs at a distance away from it.
Geometry of magnetosonic shocks and plane‐polarized waves: Coplanarity Variance Analysis (CVA)
Authors: Scudder J. D.
Published: February 2005

Minimum Variance Analysis (MVA) is frequently used for the geometrical organization of a time series of vectors. The Coplanarity Variance Analysis (CVA) developed in this paper reproduces the layer geometry involving coplanar magnetosonic shocks or plane‐polarized wave trains (including normals and coplanarity directions) 300 times more precisely (<0.1°) than MVA using the same input data. The CVA technique exploits the eigenvalue degeneracy of the covariance matrix present at planar structures to find a consistent normal to the coplanarity plane of the fluctuations. Although Tangential Discontinuities (TDs) have a coplanarity plane, the eigenvalues of their covariance matrix are usually not degenerate; accordingly, CVA does not misdiagnose TDs as shocks or plane‐polarized waves. Together CVA and MVA may be used to sort between the hypotheses that the time series is caused by a one‐dimensional current layer that has magnetic disturbances that are (1) coplanar, linearly polarized (shocks/plane waves), (2) intrinsically helical (rotational/tangential discontinuities), or (3) neither 1 nor 2.
Ageostrophic fluctuations in Cozumel Channel
Authors: Ochoa José , Candela Julio , Badan Antonio , Sheinbaum Julio
Published: February 2005

The Cayman Current flows to the west, and most of it turns north as it approaches the Yucatan coast, producing a persistent northwesterly flow on both sides of Cozumel Island. The transport between the Yucatan Peninsula and Cozumel Island (i.e., through the Cozumel Channel) is close to 5 Sverdrups in the mean, with velocities at midchannel ranging from 20 to 180 cm/s. A recent study of the subinertial flow and pressure difference across Cozumel Channel by Chávez et al. (2003) showed the existence of periods lasting over 1 month with large 3‐day to 1‐week ageostrophic fluctuations. The flow was measured again for a year, now at four locations around Cozumel Island, including two instruments along the axis of the channel 8.6 km apart, thus allowing estimations of the along‐channel velocity gradients. The new measurements reveal that, as suggested in the previous study, the centripetal or curvature acceleration of the current is the most significant contribution in the departure from geostrophy. Indeed, the curvature is, at times, so large that the pressure difference implies a geostrophic flow in the direction opposite to that of the actual flow; that is, the curvature is anticyclonic with amplitude in Rossby number larger than unity. Measures of the intensity of suprainertial variations, in pressure differences and velocity, show that periods of ageostrophic fluctuations are consistently much richer in high‐frequency fluctuations than periods of nearly geostrophic behavior. Nonetheless, the large‐scale Reynolds stresses play an insignificant role throughout.
Simple stochastic models for glacial dynamics
Authors: Ashkenazy Yosef , Baker Don R. , Gildor Hezi
Published: February 2005

Glacial‐interglacial events have several nonlinear and stochastic characteristics. Recent studies suggested additional stochastic nonlinear features (not necessarily related to the large‐scale dynamics of the glacial cycle) in the timescale of 1–100 kyr including (1) strong long‐range correlations in the magnitude of climate variable increments as well as (2) a wide multifractal spectrum. Realistic climate models should reproduce these properties of the natural system. We first study several previously proposed stochastic models for glacial‐interglacial dynamics and demonstrate that they do not reproduce some of the nonlinear properties of the paleoclimate proxy data. We then suggest two nonlinear stochastic models for glacial‐interglacial dynamics that exhibit similar stochastic nonlinear properties to those seen in the natural data. We conjecture that interaction between fast random fluctuations (representing atmospheric variability) and slowly varying fluctuations (representing oceanic variability) may underlie the observed stochastic nonlinearity of time series for glacial‐interglacial oscillations.
Seasonal and spatial variability of the size‐resolved chemical composition of particulate matter (PM10) in the Los Angeles Basin
Authors: Sardar Satya B. , Fine Philip M. , Sioutas Constantinos
Published: February 2005

For a period of almost 3 years, sampling of size‐fractionated ambient particulate matter with diameter below 10 μm (PM10) was performed at urban source sites (Downey and University of Southern California) and inland receptor sites (Claremont and Riverside) in the Los Angeles Basin as part of the Southern California Particle Center and Supersite. Results for size‐resolved PM10 mass, inorganic ions (sulfate and nitrate), metals, elemental carbon, and organic carbon were obtained. Three collocated micro‐orifice uniform deposit impactors (MOUDIs) were deployed to collect 24‐hour samples roughly once a week. Ultrafine particle concentrations (particle diameter dp < 0.1 μm) were found to be the highest at the source sites resulting from fresh vehicular emissions. Mass concentrations in the accumulation mode (0.1 < dp < 2.5 μm) were lower in winter than in summer, especially at the receptor sites. PM concentrations in the coarse mode (2.5 < dp < 10 μm) were lower in winter and were composed mostly of nitrate and crustal elements (iron, calcium, potassium, silicon, and aluminum). Consistent relative levels of these elements indicate a common source of soil and/or road dust. In the accumulation mode, nitrate and organic carbon were predominant with higher nitrate levels found at the receptor sites. The ultrafine mode PM consisted of mostly organic carbon, with higher wintertime levels at the source sites due to increased organic vapor condensation from vehicles at lower temperatures. Conversely, higher ultrafine organic carbon levels at the receptor areas are due to secondary organic aerosol formation by photochemical reactions as well as increased advection of polluted air masses from upwind.
Atmosphere of Callisto
Authors: Liang Mao‐Chang , Lane Benjamin F. , Pappalardo Robert T. , Allen Mark , Yung Yuk L.
Published: February 2005

During the Galileo flybys of Callisto in 1999, a CO2 atmosphere and an ionosphere were detected. Using the Caltech/Jet Propulsion Laboratory one‐dimensional KINETICS model, we have successfully simulated the observed electron density within a factor of 2, while satisfying the observational constraints on carbon and oxygen atoms. We conclude that photoionization of CO2 alone is insufficient to produce the observed electron density. An atmosphere 20–100 times denser than the CO2 atmosphere must be introduced, as suggested by Kliore et al. (2002). We show that an O2‐rich atmosphere is highly probable. However, the atomic oxygen produced from O2 photodissociation is 2 orders of magnitude greater than the upper limit given by Strobel et al. (2002). The introduction of reactive hydrogen chemistry assuming a surface abundance of H2O of ∼2 × 109 cm−3 (4 × 10−8 mbar) is required to reduce the excess atomic O abundance. The calculated atomic O column density is >5 × 1012 cm−2, which is about the observed upper limit, suggesting we should be able to detect O in the atmosphere of Callisto.
Evolution of the Main Ethiopian Rift in the frame of Afar and Kenya rifts propagation
Authors: Bonini Marco , Corti Giacomo , Innocenti Fabrizio , Manetti Piero , Mazzarini Francesco , Abebe Tsegaye , Pecskay Zoltan
Published: February 2005

The Main Ethiopian Rift (MER) has a complex structural pattern composed of southern, central, and northern segments. Ages of onset of faulting and volcanism apparently indicate a heterogeneous time‐space evolution of the segments, generally referred to as a northward progression of the rifting process. New structural, petrological, and geochronological data have been used to attempt reconciling the evolution of the distinct MER segments into a volcanotectonic scenario accounting for the propagation of the Afar and the Kenya Rifts. In this evolutionary model, extension affected the Southern MER in the early Miocene (20–21 Ma) due to the northward propagation of the Kenya Rift‐related deformation. This event lasted until 11 Ma, then deformation decreased radically and was resumed in Quaternary times. In the late Miocene (11 Ma), deformation focused in the Northern MER forming a proto‐rift that we consider as the southernmost propagation of Afar. No major extensional deformation affected the Central MER in this period, as testified by the emplacement at 12–8 Ma of extensive plateau basalts currently outcropping on both rift margins. Significant rift opening occurred in the Central MER during the Pliocene (∼5–3 Ma) with the eruption of voluminous ignimbritic covers (Nazret sequence) exposed both on the rift shoulders and on the rift floor. The apparent discrepancy between the heterogeneous propagation of the three MER segments could be reconciled by considering the opening of Central MER and the later reactivation of the Southern MER as due to a southward propagation of rifting triggered by counterclockwise rotation of the Somalian plate starting around 10 Ma.
On the effective measurement frequency of time domain reflectometry in dispersive and nonconductive dielectric materials
Authors: Robinson D. A. , Schaap M. G. , Or D. , Jones S. B.
Published: February 2005

Time domain reflectometry (TDR) is one of the most commonly used techniques for water content determination in the subsurface. The measurement results in a single bulk permittivity value that corresponds to a particular, but unknown, “effective” frequency (feff). Estimating feff using TDR is important, as it allows comparisons with other techniques, such as impedance or capacitance probes, or microwave remote sensing devices. Soils, especially those with high clay and organic matter content, show appreciable dielectric dispersion, i.e., the real permittivity changes as a function of frequency. Consequently, comparison of results obtained with different sensor types must account for measurement frequency in assessing sensor accuracy and performance. In this article we use a transmission line model to examine the impact of dielectric dispersion on the TDR signal, considering lossless materials (negligible electrical conductivity). Permittivity is inferred from the standard tangent line fitting procedure (KaTAN) and by a method of using the apex of the derivative of the TDR waveform (KaDER). The permittivity determined using the tangent line method is considered to correspond to a velocity associated with a maximum passable frequency; whereas we consider the permittivity determined from the derivative method to correspond with the frequency associated with the signal group velocity. The effective frequency was determined from the 10–90% risetime of the reflected signal. On the basis of this definition, feff was found to correspond with the permittivity determined from KaDER and not from KaTAN in dispersive dielectrics. The modeling is corroborated by measurements in bentonite, ethanol and 1‐propanol/water mixtures, which demonstrate the same result. Interestingly, for most nonconductive TDR measurements, frequencies are expected to lie in a range from 0.7 to 1 GHz, while in dispersive media, feff is expected to fall below 0.6 GHz.