bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlation between genomic DNA copy number alterations and transcriptional expression in hepatitis B virus‐associated hepatocellular carcinoma
Authors: Huang Jian , Sheng Hai-Hui , Shen Ting , Hu Yuan-Jie , Xiao Hua-Sheng , Zhang Qin , Zhang Qing-Hua , Han Ze-Guang
Published: May 2006

Human hepatocellular carcinoma (HCC) is one of the most common tumors worldwide, in which the genetic mechanisms of oncogenesis are still unclear. To investigate whether the genomic DNA copy number alterations may contribute to primary HCC, the cDNA microarray‐based comparative genomic hybridization (CGH) analysis was here performed in 41 primary HCC infected by hepatitis B virus and 12 HCC cell lines. The resulting data showed that, on average, 7.25% of genome‐wide DNA copy numbers was significantly altered in those samples (4.61 ± 2.49% gained and 2.64 ± 1.78% lost). Gains involving 1q, 6p, 8q and 9p were frequently observed in these cases; and whilst, losses involving Ip, 16q and 19p occurred in most patients. To address the correlation between the alteration of genomic DNA copy numbers and transcriptional expression, the same cDNA microarray was further applied in 20 HCC specimens and all available cell lines to figure out the gene expression profiles of those samples. Interestingly, the genomic DNA copy number alterations of most genes appeared not to be in generally parallel with the corresponding transcriptional expression. However, the transcriptional deregulation of a few genes, such as osteopontin (SPP1), transgelin 2 (TAGLN2) and PEG10, could be ascribed partially to their genomic aberrations, although the many alternative mechanisms could be involved in the deregulation of these genes. In general, this work would provide new insights into the genetic mechanisms in hepatocarcinogenesis associated with hepatitis B virus through the comprehensive survey on correlation between genomic DNA copy number alterations and transcriptional expression.
Silencing of HIV by hairpin‐loop‐structured DNA oligonucleotide
Authors: Moelling Karin , Abels Susanne , Jendis Joerg , Matskevich Alexey , Heinrich Jochen
Published: May 2006

We describe inhibition of HIV replication by a partially double‐stranded 54mer oligodeoxynucleotide, ODN, which consists of an antisense strand targeting the highly conserved polypurine tract, PPT, of HIV, and a second strand, compatible with triple‐helix formation. Upon treatment of HIV‐infected cells with ODN early after infection no viral nucleic acids, syncytia or p24 viral antigen expression was observed. The ODN‐mediated effect was highly sequence‐specific. The ODN against HIV‐IIIB was effective preferentially against its homologous PPT and less against the PPT of HIV‐BaL differing in two of 24 nucleotides and vice versa. It may be interesting mechanistically as an antiviral drug.
Mycobacterial adenylyl cyclases: Biochemical diversity and structural plasticity
Authors: Shenoy Avinash R. , Visweswariah Sandhya S.
Published: May 2006

The conversion of adenine and guanine nucleoside triphosphates to cAMP and cGMP is carried out by nucleotide cyclases, which vary in their primary sequence and are therefore grouped into six classes. The class III enzymes encompass all eukaryotic adenylyl and guanylyl cyclase, and several bacterial and archaebacterial cyclases. Mycobacterial nucleotide cyclases show distinct biochemical properties and domain fusions, and we review here biochemical and structural studies on these enzymes from Mycobacterium tuberculosis and related bacteria. We also present an in silico analysis of nucleotide cyclases found in completely sequenced mycobacterial genomes. It is clear that this group of enzymes demonstrates the tinkering in the class III cyclase domain during evolution, involving subtle structural changes that retain the overall catalytic function and fine tune their activities.
Genetic variation in restored Atlantic salmon (Salmo salar L.) populations in the Ulla and Lérez rivers, Galicia, Spain
Authors: Saura María , Caballero Pablo , Caballero Armando , Morán Paloma
Published: May 2006

The populations of Atlantic salmon in the Ulla and Lérez rivers, located in Galicia in northwestern Spain, were close to extinction early in the 1990s. A restoration programme involving supportive breeding has been conducted since 1995, using a mixture of salmon populations from several Galician rivers. The programme utilizes progeny of adults returning to the rivers and wild parr reared in fresh water until maturity. Five microsatellite loci were used to compare genetic variability in the restored populations with that in populations before their collapse in the 1950s. DNA samples were obtained from scale collections (old samples) and from tissue samples of live fish caught in the rivers (modern samples). Average heterozygosities and allelic richness are very similar in modern and old samples. Populations inhabiting the Ulla and Lérez rivers today are more similar than they were in the past, possibly because they originated in the same stock mixture.
Metacarpal Shaft Fractures of the Fingers: Treatment with Interosseous Loop Wire Fixation and Immediate Postoperative Finger Mobilisation in a Wrist Splint
Authors: AL-QATTAN M. M.
Published: May 2006

It is widely believed that interosseous loop wire fixation of metacarpal shaft fractures alone is not rigid enough to allow immediate postoperative mobilisation. In this report, the author reviews the results in 36 cases of metacarpal shaft fractures of the fingers treated by interosseous loop wire fixation and immediate postoperative mobilisation of all finger joints. The study included 30 males and six females, with a mean age of 31 (range 12–52) years. The fracture pattern was transverse in 26 and oblique, or spiral, in the remaining 10 patients. Following loop wire fixation, the wrist was immobilised using a volar plaster splint for 3 weeks but all finger joints were mobilised immediately after surgery. After a mean follow-up of 8 weeks, all patients, except two, had regained full range of motion of the fingers and no complications were noted. It was concluded that interosseous loop wire fixation of metacarpal shaft fractures is rigid enough to allow immediate postoperative finger mobilisation in a wrist splint and achieve good functional results.
Diagnostic Strategy for Suspected Scaphoid Fractures in the Presence of Other Fractures in the Carpal Region
Authors: BEERES F. J. P. , HOGERVORST M. , HOLLANDER P. DEN , RHEMREV S. J.
Published: May 2006

Bone scintigraphy will identify up to 25% of occult scaphoid bone fractures after negative scaphoid X-rays. Consequently, it deserves a place in the diagnostic process of suspected scaphoid fractures. However, the role of bone scintigraphy is less clear if scaphoid X-rays show other fractures in the carpal region. We analysed 111 consecutive patients with a suspected scaphoid fracture on physical examination. Scaphoid X-rays revealed 61 fractures. Fifty-five patients had scaphoid fractures only and six patients had other fractures in the carpal region but no scaphoid fracture. In 50 cases, no bone injury was seen on these X-rays. In three out of the six patients with other fractures in the carpal region, bone scintigraphy revealed four occult concomitant fractures: one scaphoid, one scaphoid and trapezial and one capitate fracture. In conclusion, bone scintigraphy is required when scaphoid X-rays do not confirm a suspected scaphoid fracture, even in the presence of other fractures in the carpal region.
The middle Cambrian cosmopolitan key species Lejopyge laevigata and its biozone: new data from Sweden
Authors: AXHEIMER NIKLAS , ERIKSSON MATS E. , AHLBERG PER , BENGTSSON ANDERS
Published: May 2006

The middle Cambrian Lejopyge laevigata Zone is poorly exposed in Scandinavia. Both this zone, however, and the succeeding Agnostus pisiformis Zone are well exposed at a classic locality at Gudhem, Västergötland, south-central Sweden. The sequences consist of finely laminated alum shale with scattered stinkstone (orsten) lenses. Three measured and sampled sections yielded a diverse fossil fauna, dominated by trilobites, in particular agnostoids, and the bradoriid Anabarochilina primordialis. Fossils are excellently preserved but restricted to the stinkstones. The L. laevigata Zone at Gudhem includes several geographically widespread key agnostoid species, notably Tomagnostella sulcifera, Clavagnostus spinosus, Glaberagnostus altaicus, Lejopyge laevigata and L. armata. The L. laevigata Zone in Scandinavia is here extended to include the traditional Solenopleura? brachymetopa Zone, and its lower boundary is defined by the FAD of L. laevigata. Trilobite evidence shows that the upper part of the Scandinavian L. laevigata Zone approximately correlates with the Proagnostus bulbus Zone of China and elsewhere.
A comparative study of patient satisfaction with day case and in-patient major ear surgery
Authors: Tysome J R , Padgham N D
Published: May 2006

Introduction: Major ear surgery can be safely performed on a day case basis (i.e. six hour stay). This study aimed to ascertain whether patients had the same level of satisfaction and speed of recovery following major ear surgery when it was performed as a day case compared with performance as an in-patient procedure.

Method: A cross-sectional survey, by postal questionnaire, of patient satisfaction with day case and in-patient major ear surgery was carried out with 158 patients. Comparisons were made between the responses of the two groups.

Results: The response rate was 71 per cent. Patients returned to work significantly sooner following day surgery (p < 0.025) but felt their operation to be of significantly more benefit following in-patient surgery (p < 0.05).

Conclusions: Patient satisfaction following day case major ear surgery is as good as that following in-patient surgery. This has supported the expansion of this service in our unit.
Prognostic relevance of anamnestic and diagnostic parameters in low-frequency hearing impairment
Authors: Maier W , Schipper J
Published: May 2006

Low-frequency hearing impairment (LFHI) is mainly attributed to endolymphatic hydrops and has a great variety of possible outcomes. At present, no conservative therapeutic regimen has proven to be ‘gold-standard’, and information about the prognostic indicators of LFHI is scarce.

In a retrospective investigation, we evaluated the records of 90 patients who had been treated with infusions improving blood perfusion. In patients lacking complete remission, dehydration infusion therapy was added. We also undertook audiometric follow up. We calculated the outcomes after infusion therapy, dehydration therapy and after long-time hearing follow up, and we determined the prognostic relevance of several parameters of anamnesis and clinical examination to outcomes, for both therapeutic interventions and long-time hearing.

The prognosis of LFHI was significantly correlated to certain anamnestic and clinical parameters; a short duration of the disease, lack of vertigo and female gender implied a better outcome. The pretherapeutic hearing threshold was an important prognostic factor; the outcome was significantly worse in patients with distinct hearing impairment in low or high frequencies, compared with that in patients with little hearing loss. Whereas vertigo was a negative prognostic factor, the results of quantitative vestibular testing were irrelevant to the outcome. The glycerol test failed to predict the effectiveness of dehydration therapy and lacked any value in predicting prognosis.

These results allow the clinician to focus the anamnesis and diagnostic examination on prognostically relevant parameters, thus enabling a better estimation of the long-term disease course and improved counselling of patients. Furthermore, these results help to distinguish valuable from irrelevant diagnostic procedures.
Evaluation of a new diagnostic modality for distal assessment of advanced, obstructing hypopharyngeal cancer
Authors: El-Monem M H Abd , Magdy Emad A
Published: May 2006

Introduction: Pre-operative endoscopic assessment of the distal extension of hypopharyngeal cancer is essential for proper surgical extirpation. This assessment is frequently not feasible in advanced, obstructing tumours.

Aims: To study the role of a proposed new diagnostic technique: intra-operative open oesophagoscopy, in distal assessment of advanced hypopharyngeal cancer.

Materials and methods: A clinicopathological study, including 35 consecutive patients with obstructing hypopharyngeal cancer.

Results: Intra-operative open oesophagoscopy revealed inferior submucosal tumour extension in 19 out of 22 cases proven histopathologically, with a sensitivity, specificity and accuracy of 86, 100 and 91 per cent, respectively. Oesophageal skip lesions were detected in two cases. Intra-operative open oesophagoscopy findings surpassed data obtained from pre-operative radiological investigations and influenced the extent of resection performed. Accordingly, 19 patients had a total laryngopharyngectomy for local disease control, while 16 patients needed an additional total oesophagectomy. Histopathologically negative inferior resection margins were obtained in all cases.

Conclusions: Intra-operative open oesophagoscopy was found to be a reliable diagnostic modality for distal assessment of obstructing hypopharyngeal cancer in cases in which pre-operative distal endoscopic examination was not feasible.
Retroperitoneal metastatic squamous cell carcinoma of the tonsil (with elevated beta human chorionic gonadotrophin): a misdiagnosis as extra-gonadal germ cell tumour
Authors: Hofmann U , O'Connor J P , Biyani C S , Harnden P , Selby P , Weston P M T
Published: May 2006

Head and neck cancers usually spread first to the regional lymph nodes but rarely may metastasize to distant sites. Metastasis to distant lymph node groups is a rare event. Furthermore, delayed multiple metastases without local recurrence is relatively uncommon. A case of retroperitoneal metastasis from a squamous cell carcinoma of the tonsil, secreting beta human chorionic gonadotrophin (β-hCG), is reported.

A 58-year-old man had undergone a tonsillectomy and chemo-radiotherapy for squamous cell carcinoma of the left tonsil and 13 months later presented with non-specific abdominal pain. The serum β-hCG levels were high and an abdominal ultrasound scan revealed hydronephrosis on the left side. A computed tomography scan demonstrated para-aortic retroperitoneal lymphadenopathy. The patient underwent an open lymph node biopsy. The initial pathological analysis was interpreted as extra-gonadal germ cell tumour and the patient received chemotherapy. A subsequent review was consistent with a metastatic squamous cell carcinoma of the tonsil, as immunohistochemical studies showed positive staining for epithelial membrane antigen and cytokeratins 5/6 but a negative reaction to placental alkaline phosphatase. Following this, the chemotherapy regimen was changed; however, a restaging scan demonstrated progression, and the patient died from aspiration pneumonia secondary to alcohol intoxication.

To our knowledge, this is the first reported case of retroperitoneal metastasis from a squamous cell carcinoma of the tonsil, secreting β-hCG and causing hydronephrosis. This case highlights the necessity of using clinical, histological, immunohistological and ultrastructural examination to establish precise diagnosis and to avoid inappropriate treatment.
Actinomycosis of the tongue: a diagnostic dilemma
Authors: Ateşpare A , Keskin G , Erçin C , Keskin S , Camcıoğlu A
Published: May 2006

Actinomycotic infections of the cervicofacial region are not uncommon. However, actinomycosis of the tongue is rare. A mass that may mimic both benign and malignant neoplasms can be seen at clinical presentation and may mislead the diagnosis.

We report a patient who presented with a tumour-like tongue mass causing speech disturbance, diagnosed as actinomycosis.
Instability of obliquely propagating dust waves in a collisional highly magnetized plasma
Authors: ROSENBERG M. , SHUKLA P.K.
Published: May 2006

We investigate the instability of obliquely propagating dust waves in a collisional, magnetized plasma containing negatively charged dust grains. It is assumed that the magnetic field strength is such that the ions and electrons are magnetized, while the dust is unmagnetized. We consider both modified two-stream and dust-acoustic instabilities that are driven by an ion cross-field drift and that occur for waves propagating obliquely to the magnetic field. We use parameters that may be representative of possible laboratory experimental conditions to illustrate the growth rates. We also compare our results with prior theoretical studies of a Hall current instability of perpendicularly propagating electrostatic waves. It is found that these obliquely propagating wave instabilities may also be important for representative laboratory parameters when the cross-field drift speed is a significant fraction of the ion thermal speed.
The structure and stability of accretion disks surrounding black holes with anomalous viscosity
Authors: CHEN YUEQI , LIU SANQIU
Published: May 2006

The solution of the steady state of accretion disks surrounding non-rotating black holes is solved by numerical simulations, where we adopt a promising viscosity prescription (i.e. anomalous magnetic viscosity). We can describe the disk more exactly than other studies, because the viscosity we adopted is close to the truth accretion disk. In contrast to previous studies, the curve of the Mach number behaves differently owing to the decline of the local sound velocity with increasing radii.

The stability of these disks has been examined. We find that the O-mode (out-mode) is always unstable and its growth rate decreases monotonically with increasing wavelength, in the inner disk and in the outer disk. The I-mode (in-mode) is unstable in the outer disk, but stable in the inner disk when the wavelength is greater than a special value.
EDITORIAL
Authors: DENORA TIA
Published: May 2006

Most of our modern Western institutions and precepts – democracy, individualism, subjectivity, secularism, science, the nation state and the modern apparatus of war – began to germinate in the ‘long’ eighteenth century. In musical life too these were formative years. The emergence of the canon, with the associated idea of the musical ‘work’, was one such development. The rise of the virtuoso and the transformation of audiences from unwieldy and fitfully attentive to enthralled, disciplined and devout, two more. And with these developments, music’s role as a medium of social differentiation was both enhanced and qualitatively revised.
TWO MORE NEW VIVALDI FINDS IN DRESDEN
Authors: STOCKIGT JANICE B. , TALBOT MICHAEL
Published: May 2006

Two further unknown sacred vocal compositions by Vivaldi, a Dixit Dominus and a Lauda Jerusalem, have turned up in a collection that has already witnessed two similar discoveries in recent decades: that of the former Saxon Hofkapelle, today in the Sächsische Landesbibliothek / Staats- und Universitätsbibliothek Dresden. Like their predecessors, the newly discovered works were acquired between the mid-1750s and early 1760s from the copying shop of Iseppo Baldan in Venice, who falsified the attribution on the title page to make the composer Galuppi instead of Vivaldi. Whereas the Lauda Jerusalem is an arrangement by Vivaldi of an anonymous stile antico setting of the same psalm in his own collection (and in turn the model for his own Credidi propter quod, rv605), the Dixit Dominus, scored for choir, soloists and orchestra, is an entirely original composition of outstanding musical quality that dates from the composer’s late period. This article explores the background to the Hofkapelle’s purchases from Baldan and provides a description of the new compositions, together with several arguments (based on musical concordances, general stylistic features and notational characteristics) for their attribution to Vivaldi.
IGNAZ HOLZBAUER AND THE ORIGINS OF GERMAN OPERA IN VIENNA
Authors: Bennett Lawrence
Published: May 2006

Ignaz Holzbauer (1711–1783) is best known for his singspiel Günther von Schwarzburg (1777), a work that deeply impressed Mozart during his sojourn in Mannheim. A much earlier German opera by Holzbauer, however, has gone virtually unnoticed. In the summer or autumn of 1741 the composer’s full-length, three-act teutsche Opera entitled Hypermnestra was performed at the Kärntnertortheater in Vienna. Following the death of Emperor Charles VI and the accession of Maria Theresia, the Kärntnertortheater Intendant Joseph Selliers commissioned a German-language opera, selecting Holzbauer, who had recently returned to Vienna from Moravia, to compose the music and the court printer Johann Leopold van Ghelen to write the libretto.

Although it is widely known that Holzbauer composed several operas in Italian before 1741, Hypermnestra appears to be the earliest opera by the composer for which a score survives. The music provides ample evidence of a mature composer in full command of opera seria style. Although Holzbauer had not yet found a satisfactory solution to the problem of narrative recitative, the opera nevertheless illustrates many of the virtues found in Günther von Schwarzburg: outstanding accompanied recitatives, a great variety in the treatment of da capo aria form and a rich array of orchestral colours.

Apart from the music, Hypermnestra is remarkable for historical reasons. It reveals that the composer had received a commission to compose an opera in the German language long before Günther von Schwarzburg. On the basis of current research it appears to hold the distinction of being one of the earliest, if not the first, full-length German opera produced in Vienna. Maria Theresia soon re-established the dominance of French and Italian styles. Nevertheless, Hypermnestra is an early example of an idea that would gradually gain acceptance and blossom during the reign of Joseph II.
STRICT AND FREE REVERSED: THE LAW OF COUNTERPOINT IN KOCH’S MUSIKALISCHES LEXIKON AND MOZART’S ZAUBERFLÖTE
Authors: CHAPIN KEITH
Published: May 2006

In his article ‘Contrapunkt’ in the Musikalisches Lexikon (1802) Heinrich Christoph Koch described the intense, suspension-filled and motivically saturated style that he and his contemporaries knew from the music of J. S. Bach in a distinctly odd manner. To show how a composer might write such music, he took a relatively consonant passage in the ‘free’ style, as he called it, and then ornamented it to create a ‘strict’ appearance. By generating the strict from the free style, Koch unconsciously registered the eighteenth-century shift from intervallic counterpoint towards chordal harmony. But as he described the strict style in this and other articles in the dictionary, Koch also intimated that the ‘strict’ style meant something quite different to him than it had to theorists of preceding generations. No longer an icon of immutable law and harmony, it seemed bizarre and dissonant, knocked from its theoretical, pedagogical and symbolic pride of place. This article first examines the theoretical issues of pedagogy and style that Koch wrestled with as he sought to make the traditional terminology of the strict style fit the compositional environment of his time, then analyses the symbolic implications of Koch’s notion of the strict style. Finally, it suggests how the symbolism of the strict style, as implied by Koch, might be manifested in the chorale fantasy sung by Two Armed Men in Schikaneder and Mozart’s Die Zauberflöte. The law of the Temple of Wisdom is not immutable, but rather represents the law of the old order, commanding respect but admitting change.
THE NON-CANONIC STATUS OF MOZART’S CANONS
Authors: ZASLAW NEAL
Published: May 2006

Mozart's canons are rather inadequately represented in the Köchel catalogue and the Neue Mozart Ausgabe. The same may be said about other music for his immediate circle of friends, colleagues and patrons, as well as his dance music and his contributions to pasticcios. Neglect of these ‘minor’ genres perhaps arises at least in part from anachronistic paradigms, for instance ‘masterpieces for posterity’. And the canons suffer additionally from the peculiar nature of their sources and transmission, from uncertainty about the position of canons in the ‘canon’ of Western art music and probably also from embarrassment over some of Mozart’s texts. Mozart’s canons have been studied not only less often than his operatic, church, chamber and orchestral music, but also less well.
A VIOLA DA GAMBA TEMPERAMENT PRESERVED BY ANTONIO STRADIVARI
Authors: POLLENS STEWART
Published: May 2006

The problem of tempering keyboard and fretted instruments has occupied the attention of musicians and theorists for hundreds of years. Since the sixteenth century most fretted instruments such as the lute and viola da gamba have employed equal temperament (or an approximation of it based upon the 18:17 rule) or an adaptation of mean-tone tuning, but these systems suffered from ‘tempered’, or ‘impure’, intervals. In 1705 the music theorist Thomas Salmon (born London, 1648; died Mepsal [now Meppershall], Bedfordshire, 1706) proposed a system of intonation for the viola da gamba that employed divided frets (that is, the frets were not tied across the fingerboard in a straight line but were in effect cut apart and glued or inset beneath each string as required) as well as interchangeable fingerboards for different keys (much like the set of crooks for the later Inventionshorn). It was Salmon’s intention to overcome the lack of purity associated with fretting systems that ‘falsify the proportions’ and thus ‘deprive us of that satisfactory pleasure which arises from the exactness of sonorous numbers’. In his system the C major scale was constructed of large and small whole tones having ratios of 9:8 for the intervals C–D, F–G and A–B, 10:9 for the intervals D–E and G–A, and 16:15 for the semitones E–F and B–C. The two sizes of whole tones were divided 18:17:16 and 20:19:18, resulting in the following scale:
Ocean color variability in the Indonesian Seas during the SeaWiFS era
Authors: Susanto R. Dwi , Moore Thomas S. , Marra John
Published: May 2006

More than 6 years of satellite‐derived ocean color (SeaWiFS) and 7 years of sea surface temperature (AVHRR) and sea surface wind (ERS1/2, NSCAT, and QuikSCAT) are investigated for the Indonesian Seas. Harmonic analysis and monthly means in ocean color indicate that during the southeast Asia‐Australia monsoon southeasterly wind from Australia generates upwelling and brings cooler and nutrient‐rich water near the surface, enhancing productivity and increasing ocean color in the Banda Sea and the southern coasts of Jawa (Java)‐Sumatra. Conditions are reversed during the northwest monsoon. The northwest wind induces downwelling and produces a weaker biological response in terms of ocean color. Anomalous winds associated with the 1997–1998 El Niño/La Niña events coinciding with the Indian Ocean Dipole (IOD) produced significant departures from the 6‐year monthly mean in both magnitude and timing of the seasonal response to the southeast monsoon. Ocean color intensified in the upwelling region along the southern coast of Jawa‐Sumatra, and the area of increased amplitude extended westward and prolonged the southeast monsoon period. In addition, localized minimum values of ocean color are observed along the exit pathways of the Indonesian Throughflow.
Morphology and structure of the Lomonosov Ridge, Arctic Ocean
Authors: Cochran James R. , Edwards Margo H. , Coakley Bernard J.
Published: May 2006

The Lomonosov Ridge is a band of continental crust that stretches across the Arctic Ocean and separates the Mesozoic Amerasian Basin from the Cenozoic Eurasian Basin. From about 87°N north of Greenland across the Pole to about 86°N, the Lomonosov Ridge is a single highstanding blocky ridge with minimum depths of ∼950–1400 m. South of 86°N on the Siberian side, the ridge breaks up into a series of ridges spread over a width of about 200 km. In this region a highstanding blocky ridge with minimum depths of ∼650–1400 m bounds the Eurasian Basin and continues to the Siberian continental margin. This ridge is continuous with the single ridge making up the Lomonosov Ridge toward North America and is the former outermost continental shelf of Eurasia bounding the Amerasian Basin. The Eurasian Basin margin of the Lomonosov Ridge consists of a series of rotated fault blocks stepping down to the basin that result from nearly orthogonal rifting to form the Eurasian Basin. No rotated fault blocks are observed on the Amerasian Basin margin of the Lomonosov Ridge. On the Amerasian Basin side, Marvin Spur, a linear ridge separated from Lomonosov Ridge by a deep basin, parallels Lomonosov Ridge on the North American side of the pole. At the bend in the Lomonosov Ridge near the North Pole, Marvin Spur continues along strike across the Makarov Basin. South of 86°N toward Siberia, a continuous outer ridge makes up the Amerasian Basin edge of the Lomonosov complex with a series of basins and ridges between it and the former Eurasian shelf. The outer ridge marks an abrupt boundary between the Lomonosov Ridge complex and the apparently oceanic crust of the Makarov Basin. The outer ridge and Marvin Spur very closely follow small circles about a pole located on the Mackenzie delta. The observed structure on the Amerasian Basin side of the Lomonosov Ridge is analogous to that observed at well‐studied shear margins and supports rotational models for the development of the Amerasian Basin.
Fluxes and origin of halogenated organic trace gases from Momotombo volcano (Nicaragua)
Authors: Frische Matthias , Garofalo Kristin , Hansteen Thor H. , Borchers Reinhard
Published: May 2006

In order to assess the contribution of quiescent degassing volcanoes to the global halo(hydro)carbon inventory, we have quantified volcanic fluxes of methyl halides (CH3Cl, CH3Br, and CH3I), ethyl halides (C2H5Cl, C2H5Br, and C2H5I), and higher chlorinated methanes (CH2Cl2, CHCl3, and CCl4). About every eight months over a 2‐year period (July 2001 to July 2003), gas samples were collected and analyzed from high‐temperature fumaroles (472°C–776°C) at the Nicaraguan subduction zone volcano Momotombo. Using a simultaneous record of trace and main compounds in fumarolic gases as well as SO2 fluxes of the plume, we were able to calculate halo(hydro)carbon fluxes for Momotombo and extrapolate our results to estimate halo(hydro)carbon fluxes for the whole Quaternary Nicaraguan volcanic arc and, in addition, for all volcanoes globally. The most abundant halohydrocarbon was CH3Cl with concentrations up to 19 ppmv. Further major halo(hydro)carbons were CH3Br, CH3I, CH2Cl2, CHCl3, CCl4, C2H5Cl, C2H5Br, C2H5I, and C2H3Cl with an average concentration of 0.20 to 720 ppbv. Estimated mean halo(hydro)carbon fluxes from Momotombo were in the range of 630–5000 g/yr for methyl halides, 49–260 g/yr for ethyl halides, and 2.4–24 g/yr for higher chlorinated methanes. When the results for Momotombo are scaled up to SO2 fluxes of the Nicaraguan volcanic transect, fluxes of 1.7 × 105 g/yr CH3Cl and 82 g/yr CCl4 are attained for Nicaragua. Scaled up to the estimated global SO2 flux, this translates to hypothetical global fluxes of 5.6 × 106 g/yr CH3Cl and 2.7 × 103 g/yr CCl4. These volcanic fluxes are negligible compared to global anthropogenic and natural emissions of about 3 × 1012 g/yr CH3Cl and 2 × 1010 g/yr CCl4.
Kinetic simulations of x‐line expansion in 3D reconnection
Authors: Lapenta Giovanni , Krauss‐Varban D. , Karimabadi H. , Huba J. D. , Rudakov L. I. , Ricci Paolo
Published: May 2006

The dynamics of x‐line formation and evolution in 3D magnetic reconnection is studied using a fully kinetic approach. An x‐line of small length is initialized using a perturbation localized in the current direction. The electrons and ions drift diamagnetically along the current direction of the initial x‐line and are further accelerated by the reconnection electric field. The electron and ion motion is in opposite directions and each species extends one end of the x‐line. Several predictions based on this picture are formulated and studied and confirmed under parameter variation. Expansion can proceed at a significant fraction of the Alfvén speed, in both directions.
Unified PCN and PCS indices: Method of calculation, physical sense, and dependence on the IMF azimuthal and northward components
Authors: Troshichev Oleg , Janzhura Alexander , Stauning Peter
Published: May 2006

The PC index estimates the polar cap magnetic activity generated by the solar wind and its embedded magnetic field. It shows a high degree of correlation with geophysical disturbance parameters characterizing the state of magnetosphere. After transition to 1‐min PC index values, significant differences were revealed between the PCN and PCS indices, derived on the basis of magnetic data from Thule and Vostok stations, respectively. Differences in values of the 1‐min PCN and PCS indices may give rise to discrepancy in results of various analyses and to quite erroneous physical conclusions. To eliminate any influence of the calculation technique on scientific results a unified method for derivation of the PC index was elaborated in the Arctic and Antarctic Research Institute (St. Petersburg) and Danish Meteorological Institute (Copenhagen), and new sets of the unified PCN and PCS indices were calculated. Under conditions of southward IMF the unified positive PCS and PCN indices are well consistent with one another in their value and behavior and linearly correlate with the solar wind merging electric field (MEF), irrespective of season. The IMF BY component is responsible for occurrence of the electric field MEF (and positive PC index) under conditions BZ > 0. Being proportional to MEF the PC index would be regarded as a measure of the interplanetary merging (geoeffective) electric field with the appropriate dimensionality of mV/m.
Unusual early morning development of the equatorial anomaly in the Brazilian sector during the Halloween magnetic storm
Authors: Batista Inez S. , Abdu M. A. , Souza J. R. , Bertoni F. , Matsuoka M. T. , Camargo P. O. , Bailey G. J.
Published: May 2006

The solar events that occurred at the end of October 2003 gave rise to very strong geomagnetic disturbances that peaked twice with Dst values reaching −345 nT around 0000 UT on 30 October and −400 nT around 2300 UT, on the same day. Disturbances in several ionospheric parameters were observed over Brazil. This work will focus on the ionospheric response to the initial westward prompt penetration electric field and on the strong intensification of the equatorial ionization anomaly that occurred because of the electric field polarity reversal that followed in the early morning hours of 29 October. The F layer peak height over the equator first decreased under the strong prompt penetration westward electric field, which was followed by significant height increase under eastward electric field. We have used Sheffield University Plasmasphere Ionosphere Model (SUPIM) with an intensified westward disturbed electric field in the presunrise hours, presumably due to prompt penetration from the magnetosphere, in order to study the effect of such a field in the ionosphere. The simulation results showed that prompt penetration of magnetospheric electric fields of westward polarity to the nightside equatorial region seems to be the most probable cause of the initial F layer height decreases. The intensification of the equatorial ionization anomaly and the unusual enhancement on F layer peak density, which was not modeled by the SUPIM, are explained as caused by the strong eastward electric field that followed the initial phase in combination with a highly variable disturbed meridional/transequatorial wind system as inferred from the F2 layer peak height variations. The highly dynamic wind pattern, with a short‐term response (2–4 hours), is compatible with the predictions of some previous theoretical model calculations reported in the literature.
Heating and weakening of faults during earthquake slip
Authors: Rice James R.
Published: May 2006

Field observations of mature crustal faults suggest that slip in individual events occurs primarily within a thin shear zone, <1–5 mm, within a finely granulated, ultracataclastic fault core. Relevant weakening processes in large crustal events are therefore suggested to be thermal, and to involve the following: (1) thermal pressurization of pore fluid within and adjacent to the deforming fault core, which reduces the effective normal stress and hence also the shear strength for a given friction coefficient and (2) flash heating at highly stressed frictional microcontacts during rapid slip, which reduces the friction coefficient. (Macroscopic melting, or possibly gel formation in silica‐rich lithologies, may become important too at large enough slip.) Theoretical modeling of mechanisms 1 and 2 is constrained with lab‐determined hydrologic and poroelastic properties of fault core materials and lab friction studies at high slip rates. Predictions are that strength drop should often be nearly complete at large slip and that the onset of melting should be precluded over much (and, for small enough slip, all) of the seismogenic zone. A testable prediction is of the shear fracture energies that would be implied if actual earthquake ruptures were controlled by those thermal mechanisms. Seismic data have been compiled on the fracture energy of crustal events, including its variation with slip in an event. It is plausibly described by theoretical predictions based on the above mechanisms, within a considerable range of uncertainty of parameter choices, thus allowing the possibility that such thermal weakening prevails in the Earth.
Spatial and temporal variability of black carbon in New York City
Authors: Venkatachari Prasanna , Zhou Liming , Hopke Philip K. , Felton Dirk , Rattigan Oliver V. , Schwab James J. , Demerjian Kenneth L.
Published: May 2006

Measurements of black carbon (BC) were made at two sites in New York City during the winter of 2004 and are compared. Spatial and temporal variability in the black carbon concentrations were explored by examining the diurnal, weekday/weekend, and day‐of‐week trends in black carbon concentrations at these two sites. It was observed that BC tracked PM2.5 well at the Queens site and contributed about 8% to the fine particle mass measured at this site. At the IS 52 site, however, BC did not track PM2.5 as well and accounted for a slightly higher 11% of the total fine mass. Diurnal BC behavior was observed during weekdays as well as weekends consistent with traffic patterns and atmospheric mixing conditions. However, a clear day‐of‐week dependence of BC concentrations was not observed. Conditional probability functions were computed using the surface wind data and the BC concentrations at the two sites and were used to identify local point sources. Associations of black carbon with gaseous pollutants such as CO, NOx, and nonmethane hydrocarbons are also explored for the Queens site in an attempt to identify the temporal variations in their emissions. It was found that the concentrations of black carbon vary in response to the interplay of source activity, meteorological conditions, and spatial factors. The high time resolution measurements were found to yield insights into the spatial scales of emissions that are not possible with longer timescale measurements such as 24 hour averages.
Observations of Asian air pollution in the free troposphere at Mount Bachelor Observatory during the spring of 2004
Authors: Weiss‐Penzias Peter , Jaffe Daniel A. , Swartzendruber Philip , Dennison James B. , Chand Duli , Hafner William , Prestbo Eric
Published: May 2006

This paper describes the chemical, aerosol, and meteorological measurements taken at Mount Bachelor Observatory (MBO), a new mountaintop site in central Oregon, USA (44.0°N, 121.7°W, 2763 m above mean sea level). During the initial campaign (28 March to 19 May 2004) we evaluated the utility of this location as a site to observe the global atmosphere, especially the free troposphere (FT). We observed some boundary layer (BL)/upslope flow during the daytime, which produced a 37–62% higher average water vapor mixing ratio (WV) compared to radiosonde data taken from similar altitudes in western Oregon. However, recently subsided air masses with low WV contained significantly elevated concentrations of carbon monoxide (CO), total gaseous mercury (TGM), and ozone (O3), (25 ppbv, 0.16 ng/m3, and 13.9 ppbv, respectively), compared to periods with high‐WV measurements. These enhancements represent a significant influence from Asian long‐range transport (ALRT). One specific time period (“event”) on 25 April produced some of the largest CO, TGM, O3, and particulate scattering (σsp) measurements ever seen along the West Coast due to ALRT. Enhancement ratios between these species are consistent with the major source being Asian industrial emissions. In particular, the ΔTGM/ΔCO enhancement ratio was 0.0045–0.0048 ng/m3/ppbv for all ALRT events, similar to the value previously obtained from pollution plumes directly downwind of east Asia. A smaller pollution event of North American origin produced a ΔTGM/ΔCO value of only 0.0013 ng/m3/ppbv, suggesting that the ΔTGM/ΔCO value is an effective tracer of ALRT. Finally, thousands of kinematic back trajectories were calculated for each event to evaluate sources and transport processes.
Two highly singular intermittent structures: Rain and turbulence
Authors: Waymire Edward C.
Published: May 2006

Rainfall charges soil moisture and river basins among its many roles with respect to the hydrologic cycle. Research aimed at improved understanding and modeling of surface water processes includes attention to rainfall at a variety of space‐time scales. Given the atmospheric environment in which rain events are observed, some similarities between certain rainfall data structures and fluid turbulence can be expected. So the space‐time intermittency and large fluctuations observed in both rain rates and energy dissipation rates have provided an interest among hydrologists in developing physical theories, experiments, and mathematical models. In response to a request for insights into multiplicative cascade models, the main goal of this article is to single out a special mathematical transformation, namely, “size biasing” (or “tilting”), which has proven to be very powerful in the mathematical analysis of multiplicative cascades and which has also been successfully exploited within the context of turbulence from a physical perspective.
Modeling flow and transport in highly heterogeneous three‐dimensional aquifers: Ergodicity, Gaussianity, and anomalous behavior—1. Conceptual issues and numerical simulations
Authors: Janković I. , Fiori A. , Dagan G.
Published: May 2006

Uniform flow of mean velocity U takes place in a highly heterogeneous, isotropic, aquifer of lognormal conductivity distribution (variance σY2, integral scale I). A conservative solute is injected instantaneously over an area A0 at x = 0, normal to the mean flow, in a flux‐proportional mode. Longitudinal spreading is caused by advection by the fluid velocity and is quantified with the aid of the mass flux μ(t, x) through fixed control planes at x. An equivalent macrodispersivity is defined in terms of the traveltime variance. The flow and transport are solved numerically in three realizations of the conductivity field with σY2 = 2, 4, 8, respectively. The medium is modeled by a collection of a large number N = 100,000 of spherical inclusions whose conductivities are drawn at random. Transport is simulated by tracking 40,000 particles originating at a large injection area (A0 ≃ 2000 I2) and for travel distance x ≤ 121 I. It is found that the mass flux has a highly skewed time distribution because of the late arrival of solute particles that are moving through low‐conductivity blocks. The tail leads to large values of the equivalent macrodispersivity, which is highly dependent on cutoffs corresponding to the arrival of even 0.999 or 0.995 of the total mass. Furthermore, the tail is nonergodic, as it depends on the plume size. Transport appears to be anomalous in the considered interval, although by the central limit theorem it has to tend asymptotically to Fickianity and Gaussianity.
Modeling flow and transport in highly heterogeneous three‐dimensional aquifers: Ergodicity, Gaussianity, and anomalous behavior—2. Approximate semianalytical solution
Authors: Fiori A. , Janković I. , Dagan G.
Published: May 2006

Flow and transport take place in a heterogeneous medium of lognormal distribution of the conductivity K. Flow is uniform in the mean, and the system is defined by U (mean velocity), σY2 (log conductivity variance), and integral scale I. Transport is analyzed in terms of the breakthrough curve of the solute, identical to the traveltime distribution, at control planes at distance x from the source. The “self‐consistent” approximation is used, where the traveltime τ is approximated by the sum of τ pertinent to the different separate inclusions, and the neglected interaction between inclusions is accounted for by using the effective conductivity. The pdf f(τ, x), where x is the control plane distance, is derived by a simple convolution. It is found that f(τ, x) has an early arrival time portion that captures most of the mass and a long tail, which is related to the slow solute particles that are trapped in blocks of low K. The macrodispersivity is very large and is independent of x. The tail f(τ, x) is highly skewed, and only for extremely large x/I, depending on σY2, the plume becomes Gaussian. Comparison with numerical simulations shows very good agreement in spite of the absence of parameter fitting. It is found that finite plumes are not ergodic, and a cutoff of f(τ, x) is needed in order to fit the mass flux of a finite plume, depending on σY2 and x/I. The bulk of f(τ, x) can be approximated by a Gaussian shape, with fitted equivalent parameters. The issue of anomalous behavior is examined with the aid of the model.
Theoretical determination of the Raman spectra of MgSiO3 perovskite and post‐perovskite at high pressure
Authors: Caracas Razvan , Cohen Ronald E.
Published: May 2006

We use the density functional perturbation theory to determine for the first time the pressure evolution of the Raman intensities for a mineral, the two high‐pressure structures of MgSiO3 perovskite and post‐perovskite. At high pressures, the Raman powder spectra reveals three main peaks for the perovskite structure and one main peak for the post‐perovskite structure. Due to the large differences in the spectra of the two phases Raman spectroscopy can be used as a good experimental indication of the phase transition.
Dipolar and non‐dipolar dynamos in a thin shell geometry with implications for the magnetic field of Mercury
Authors: Takahashi Futoshi , Matsushima Masaki
Published: May 2006

Dynamo action possibly working in the fluid core of Mercury is examined using numerical models in a thin spherical shell. Dipolar (DP) dynamos are obtained in the regime of columnar flows outside the tangent cylinder (TC), whereas non‐dipolar (NDP) dynamos dominated by the multipole components are found in the regime of flows both inside and outside the TC. It turns out that columnar‐like convective motions not only outside but also inside the TC are responsible for the NDP dynamo. The electrically conducting inner core enhances the strength of large‐scale magnetic field, but predominance of the NDP components remains due to the thin shell geometry. These results suggest that Mercury may have more complicated magnetic field than has been considered.