bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of plasma biomarkers in acute heart failure. Serial changes and independent prognostic value of NT‐proBNP and cardiac troponin‐T
Authors: Metra Marco , Nodari Savina , Parrinello Giovanni , Specchia Claudia , Brentana Loretta , Rocca Patrizia , Fracassi Francesco , Bordonali Tania , Milani Patrizia , Danesi Rossella , Verzura Giulia , Chiari Ermanna , Cas Livio Dei
Published: June 2007

Aims

Brain natriuretic peptide (BNP), NT‐proBNP and troponins are useful for the assessment of patients with heart failure. Few data exist about their serial changes and their prognostic value in patients with acute heart failure (AHF).

Methods and results

NT‐proBNP and troponin‐T plasma levels were measured at baseline, after 6, 12, 24, 48 h and at discharge in 116 consecutive patients with AHF and no evidence of acute coronary syndrome. NT‐proBNP levels were 4421 pg/mL at baseline, declined after 24 h and reached their nadir at 48 h (2703 pg/mL). Troponin‐T was detectable in 48% of patients. During a median follow‐up of 184 days, 52 patients died or had a non‐fatal cardiovascular hospitalisation. At a multivariable analysis including clinical and echo‐Doppler variables, NT‐proBNP plasma levels at discharge, detectable troponin‐T plasma levels, and NYHA class at discharge were the only independent prognostic factors.

Conclusion

In patients with AHF, NT‐proBNP levels decline 24 h after the initiation of intravenous therapy and troponin‐T is detectable in 48% of cases. NT‐proBNP levels at discharge, detectable troponin‐T levels, NYHA class and serum sodium have independent prognostic value.
Low‐dose hormone therapy in the perimenopause
Authors: De Franciscis P. , Cobellis L. , Fornaro F. , Sepe E. , Torella M. , Colacurci N.
Published: June 2007

Objective: To evaluate the effects of low‐dose hormone therapy (LD‐HT) on bleeding pattern and vasomotor symptoms in perimenopausal women. Methods: In a prospective, open‐label study at an University clinic, 120 perimenopausal women suffering from irregular menstrual cycles and hot flushes were randomized to micronized 17β‐estradiol 1 mg plus dydrogesterone 10 mg sequential added (LD‐HT; group A: 60 subjects) or dydrogesterone 10 mg from day 15 to 28 (group B: 60 subjects). Number and severity of hot flushes and bleeding pattern were assessed throughout the study. Results: Women in group A experienced a significant reduction in number of hot flushes while no significant variation was observed in group B. The incidence of cyclic bleeding was 86% in group A and 76% in group B, the mean duration was significantly lower in group A than in group B. Conclusions: LD‐HT may control both irregular bleeding and hot flushes in perimenopausal women.
Peripheral blood lymphocyte subpopulations in patients with cervical cancer
Authors: Das S. , Karim S. , Datta Ray C. , Maiti A.K. , Ghosh S.K. , Chaudhury K.
Published: June 2007

Objective: Impairment of cell‐mediated immunity in carcinoma of the cervix (CA CX) and cervical intraepithelial neoplasia (CIN) are reported. Contradictory reports exist on lymphocyte subpopulations associated with this disease. The present study aims to quantitatively analyze peripheral blood lymphocytes subsets in patients with CA CX and CIN. Method: Systemic T lymphocyte subsets, CD19+, CD16+ and CD56+ cells in 58 CA CX and 10 CIN patients were studied. The lymphocyte phenotypes were quantified by monoclonal antibodies (anti‐CD4, CD8, CD16, CD19 and CD56). Result: Significant decrease in CD4+ cell population was observed in CA CX and CIN patients as compared to controls (P ≤ 0.05). CD4+/CD8+ ratio was observed to be less in CIN patients (P ≤ 0.001). Other lymphocyte subpopulations appeared to be comparable between the groups. Conclusion: Results indicate immunological abnormalities in invasive CA CX and CIN patients. Study on a larger patient population may provide a biomarker for early detection of this disease.
Laparoscopically assisted balloon vaginoplasty for management of vaginal aplasia
Authors: El Saman A.M. , Fathalla M.M.F. , Nasr A.M. , Youssef M.A.
Published: June 2007

Objective: To report the intra‐operative and post‐operative results of laparoscopically assisted balloon vaginoplasty, a new technique for management of vaginal aplasia. Methods: Eight women with vaginal aplasia due to Mullerian agenesis who were referred for apareunia, dyspareunia. All had a poor penetration score and sexual satisfaction score. A Foley's catheter was laparoscopically inserted in the space between the urethra and rectum. Gradual traction and distension were used to create a neovagina. Outcomes measured were intra‐operative complications, post‐operative complications, length of the neovagina and post‐operative complications and sexual satisfaction score in both partners. Results: Mean operative time was 25.5 +/− 5.5 min. No operative complications were recorded. Pain scores ranged from zero to 30 points at rest and from 30 to 60 points during dressing, traction and distension. Penetration and satisfaction scores increased significantly after the operation. Conclusions Balloon vaginoplasty is a simple, safe and satisfactory technique for management of blind vagina.
Reproductive health and public health ethics
Authors: Dickens B.M. , Cook R.J.
Published: June 2007

Individuals' reproductive choices are private matters, but sexual conduct and pregnancy impose significant public health burdens. Ethical principles of public health are distinguishable from principles applied in modern bioethics. Bioethical principles have been developed at the clinical or microethical level, affecting relations among individuals, whereas pubic health ethics applies at the population‐based or macroethical level. Resolution of issues, for instance of consent to healthcare interventions and preservation of privacy, is different in public health practice from in clinical medicine. Public health aspects of human reproduction concern reduction of maternal mortality and morbidity, particularly in resource‐poor countries, and the contribution to high rates of each of unsafe abortion, most prevalent where abortion laws are restrictive. Further aspects of public health ethics concern limited access to contraceptive services, the spread of sexually transmitted infections (STIs), including HIV, causes of infertility, especially due to STIs, and responses to each of these concerns.
Effects of a novel anti-exospore monoclonal antibody on microsporidialNosema bombycisgermination and reproductionin vitro
Authors: ZHANG F. , LU X. , KUMAR V. S. , ZHU H. , CHEN H. , CHEN Z. , HONG J.
Published: June 2007

A monoclonal antibody (mAb) 3C2, against an exospore protein of the microsporidiumNosema bombycis(N. bombycis) was prepared, and its effects on microsporidial germination and reproductionin vitrowere studied. MAb 3C2 was effective in inhibiting the germination and subsequent infection ofBombyx moricells compared to the control mAb. The antigen was isolated by 2-dimensional gel electrophoresis. Immunoblotting revealed it to be an 84 kDa protein corresponding to pI (7·2) on the 2-D gel. The present results suggest that the antibodies can be used for diagnostic purposes and for developing new therapeutic strategies in controlling microsporidian diseases.
Trypanosoma bruceivacuolar protein sorting 41 (VPS41) is required for intracellular iron utilization and maintenance of normal cellular morphology
Authors: LU S. , SUZUKI T. , IIZUKA N. , OHSHIMA S. , YABU Y. , SUZUKI M. , WEN L. , OHTA N.
Published: June 2007

Procyclic forms ofTrypanosoma brucei bruceiremain and propagate in the midgut of tsetse fly where iron is rich. Additional iron is also required for their growth inin vitroculture. However, little is known about the genes involved in iron metabolism and the mechanism of iron utilization in procyclic-form cells. Therefore, we surveyed the genes involved in iron metabolism in theT. b. bruceigenome sequence database. We found a potential homologue of vacuole protein sorting 41 (VPS41), a gene that is required for high-affinity iron transport inSaccharomyces cerevisiaeand cloned the full-length gene (TbVPS41). Complementation analysis of TbVPS41 in ΔScvps41yeast cells showed that TbVPS41 could partially suppress the inability of ΔScvps41yeast cells to grow on low-iron medium, but it could not suppress the fragmented vacuole phenotype. Further RNA interference (RNAi)-mediated gene knock-down in procyclic-form cells resulted in a significant reduction of growth in low-iron medium; however, no change in growth was observed in normal culture medium. Transmission electron microscopy showed that RNAi causedT. b. bruceicells to have larger numbers of small intracellular vesicles, similar to the fragmented vacuoles observed in ΔScvps41yeast cells. The present study demonstrates that TbVPS41 plays an important role in the intracellular iron utilization system as well as in the maintenance of normal cellular morphology.
Morphological and molecular diversity and phylogenetic relationships among anuran trypanosomes from the Amazonia, Atlantic Forest and Pantanal biomes in Brazil
Authors: FERREIRA R. C. , CAMPANER M. , VIOLA L. B. , TAKATA C. S. A. , TAKEDA G. F. , TEIXEIRA M. M. G.
Published: June 2007

We examined for the presence of trypanosomes in blood samples from 259 anurans (47 species from 8 families), the majority of which were from the Brazilian Amazonia, Atlantic Forest and Pantanal biomes. Trypanosomes were detected by a combination of microhaematocrit and haemoculture methods in 45% of the anurans, and 87 cultures were obtained: 44 from Hylidae, 22 from Leptodactylidae, 15 from Bufonidae, 5 from Leiuperidae and 1 from an unidentified anuran. High morphological diversity (11 morphotypes) was observed among blood trypanosomes from anurans of different species and of the same species as well as among trypanosomes from the same individual. Conversely, morphologically similar trypanosomes were found in anurans from distinct species and biomes. ITS and SSU rDNA polymorphisms revealed high diversity among the 82 isolates examined.† Twenty-nine genotypes could be distinguished, the majority distributed in 11 groups. Phylogenetic relationships based on rDNA sequences indicated that isolates from more phylogenetically related anurans are more closely related. Comparison of anuran trypanosomes from Brazil and other countries revealed several new species among the isolates examined in this study. Phylogenetic relationships suggest that host restriction, host switching and overall ecogeographical structure may have played a role in the evolution of the anuran trypanosomes.
Comparative evaluation ofGiardia duodenalissequence data
Authors: WIELINGA C. M. , THOMPSON R. C. A.
Published: June 2007

A review of theGiardia duodenalissequences currently available on the GenBank database was completed to compare the different genotyping loci (small subunit ribosomal DNA, glutamate dehydrogenase, triose-phosphate isomerase and beta giardin) for their ability to discern assemblage and subassemblage groups and infer phylogenetic relationships. In total, 405Giardia duodenalissequences were sorted and aligned to examine the substitutions within and between the assemblages – A and B (zoonotic), C and D (dogs), E (livestock), F (cats) and G (rodents). It was found that all of the genes could reproducibly group isolates into their assemblages and that the AI/AII subassemblage groups were robust and identifiable at all loci. However, the assemblage B subgroups were not reproducible at half of the loci (small subunit ribosomal DNA and beta giardin), not due to their conserved nature, but because there was insufficient sequence data of reference isolates available for comparison. It is anticipated that further investigation of these loci may reveal the core subgroups of this medically important and zoonotic assemblage and also those of others. The closer, more recent, phylogenetic relationships amongst the assemblages appear to be resolved; however, more sequence data from the current loci, and possibly new loci, will be required to establish the remaining relationships.
Research on the enhancement of power-load of two-cell SBS system by choosing different media or mixture medium
Authors: Hasi W.L.J. , Lu Z.W. , Li Q. , He W.M.
Published: June 2007

In order to enhance the power-load of two-cell stimulated Brillouin scattering (SBS) system, methods of using different media and mixed medium are proposed. In theory, the amplification function of two-cell system of different medium with close vicinity in the Brillouin frequency shift (BFS) is analyzed. Also the variation of BFS of the mixed medium with the mixing ratio is analyzed. In the two-cell SBS system pumped by Q-switched Nd:YAG laser, the SBS system performance characteristics are investigated with different media and mixed medium. The experimental results indicate that the Stokes can be sufficiently amplified by choosing different medium with close vicinity in the BFS; the power-load performance is enhanced as well as the maximum amplification efficiency the Stokes by choosing mixed medium.
High-power Ti:Sapphire lasers: Temporal contrast and spectral narrowing
Authors: Kalashnikov M , Osvay K , Sandner W
Published: June 2007

New extensions of the chirped pulse amplification (CPA) scheme designed specially for petawatt Ti:Sapphire lasers are considered. The two new schemes support a spectral bandwidth sufficient for 20 fs pulses and a temporal contrast of 1012. The Double CPA scheme consists of two CPA stages with an intermediate temporal pulse filtering for temporal contrast improvement. The scheme of Negative–Positive CPA amplification takes advantage of consecutive saturated amplification of down chirped and up chirped pulses. This allows a suppress imprint of gain narrowing, which usually limits the spectral bandwidth at the multi-terawatt power level, and reach the bandwidth in excess of 50 nm without using any direct spectral shaping of the pulse.
High resolution X-ray emission spectra from picosecond laser irradiated Ge targets
Authors: Abdallah J. , Batani D. , Desai T. , Lucchini G. , Faenov A. , Pikuz T. , Magunov A. , Narayanan V.
Published: June 2007

Investigations of a high resolution X-ray emission spectrum in the range 0.66–0.75 nm obtained by irradiating a Germanium target with high-power p-polarized, 40 picosecond laser radiation at 532 nm wavelength was done. Spectra in the wavelength region of 2l-4l′ and 2l-5l′ L-shell transitions in F-like, Ne-like and Na-like germanium ions were recorded using the FSSR-2D spectrometer equipped with a spherically bent quartz crystal with a spectral resolution λ/Δλ better than 5000. Spectral lines were compared with theoretical values obtained using the LANL plasma kinetic code ATOMIC. Fair agreement between experimental and theoretical spectral lines has been observed, which allowed to measure enough high bulk electron temperature values of 560 eV and electron density of ∼1021 cm−3 in Ge plasma irradiated by rather small commercial high repetition rate Nd:YAG laser system.
Polarization effect of fields on vacuum laser acceleration
Authors: XU J.J. , KONG Q. , CHEN Z. , WANG P.X. , WANG W. , LIN D. , HO Y.K.
Published: June 2007

Concerning laser-driven electron acceleration in vacuum, a comparison was made between using circularly polarized (CP) laser field and linearly polarized (LP) field. It has been found that the main advantage for using CP field is that its acceleration channel occupies relatively larger phase space, which can give rise to greater acceleration efficiency. This feature chiefly comes from the difference in the distribution of the longitudinal electric components of these two kinds of fields. One of the disadvantages with CP field is the “energy saturation” phenomenon as the laser intensity is sufficiently high, resulting from the enhanced Lorentz force component in CP field. Physical explanations of these characteristics are addressed as well.
X-ray spectroscopy observation of fast ions generation in plasma produced by short low-contrast laser pulse irradiation of solid targets
Authors: Faenov A.YA. , Magunov A.I. , Pikuz T.A. , Skobelev I. YU. , Gasilov S.V. , Stagira S. , Calegari F. , Nisoli M. , de Silvestri S. , Poletto L. , Villoresi P. , Andreev A.A.
Published: June 2007

X-ray spectra of plasma produced by the interaction of Ti:Sa laser pulses (duration from 60 fs to 1 ps, and energy from 15 mJ to 128 mJ) with foil and solid Teflon and AL targets are investigated. It is shown experimentally and theoretically that the use of low contrast (10−2 – 10−4) short laser pulses, essentially promotes the conditions for generation of fast multi-charged ions. This effect is caused by self-focusing of the main laser pulse in a preplasma produced by intense laser prepulses. Modeling of the observed spectral line shape gives evidence of a considerable (about 3%) amount of multi-charged He-like F ions with energy E ∼ 1 MeV at rather low values of laser intensity IL ≈ 6 × 1016 W cm−2.
Intense harmonic generation from silver ablation
Authors: Ozaki T. , Elouga Bom L.B. , Ganeev R. , Kieffer J.-C. , Suzuki M. , Kuroda H.
Published: June 2007

We perform systematic investigation of a new method for generating high-order harmonics, using ablation as the nonlinear medium. We place emphasis on clarifying the pump laser conditions for optimum harmonic yield. For this purpose, we use the Ti:Sapphire laser beams of the advanced laser light source (800 nm wavelength, 360 mJ total energy). We have independently varied the intensity of the prepulse (which creates the plasma ablation) and the intensity of the main pulse (which generates the harmonics), and studied their influence on the harmonic intensity. We show here that the presence of doubly ionized atoms in the ablation, created either by a strong prepulse intensity or by irradiating the main pulse, will suppress harmonic generation.
Fast Frequent Querying with Lazy Control Flow Compilation
Authors: TRONÇON REMKO , JANSSENS GERDA , DEMOEN BART , VANDECASTEELE HENK
Published: June 2007

Control flow compilation is a hybrid between classical WAM compilation and meta-call, limited to the compilation of non-recursive clause bodies. This approach is used successfully for the execution of dynamically generated queries in an inductive logic programming setting (ILP). Control flow compilation reduces compilation times up to an order of magnitude, without slowing down execution. A lazy variant of control flow compilation is also presented. By compiling code by need, it removes the overhead of compiling unreached code (a frequent phenomenon in practical ILP settings), and thus reduces the size of the compiled code. Both dynamic compilation approaches have been implemented and were combined with query packs, an efficient ILP execution mechanism. It turns out that locality of data and code is important for performance. The experiments reported in the paper show that lazy control flow compilation is superior in both artificial and real life settings.
Reasoning and planning with sensing actions, incomplete information, and static causal laws using answer set programming
Authors: TU PHAN HUY , SON TRAN CAO , BARAL CHITTA
Published: June 2007

We extend the 0-approximation of sensing actions and incomplete information in Son and Baral (2001) to action theories with static causal laws and prove its soundness with respect to the possible world semantics. We also show that the conditional planning problem with respect to this approximation isNP-complete. We then present an answer set programming based conditional planner, called ASCP, that is capable of generating both conformant plans and conditional plans in the presence of sensing actions, incomplete information about the initial state, and static causal laws. We prove the correctness of our implementation and argue that our planner is sound and complete with respect to the proposed approximation. Finally, we present experimental results comparing ASCP to other planners.
Updates in answer set programming: An approach based on basic structural properties
Authors: OSORIO MAURICIO , CUEVAS VÍCTOR
Published: June 2007

We have studied the update operator ⊕1 defined for update sequences by Eiter et al. without tautologies and we have observed that it satisfies an interesting property. This property, which we call Weak Independence of Syntax (WIS), is similar to one of the postulates proposed by Alchourrón, Gärdenfors, and Makinson (AGM); only that in this case it applies to nonmonotonic logic. In addition, we consider other five additional basic properties about update programs and we show that ⊕1 satisfies them. This work continues the analysis of the AGM postulates with respect to the ⊕1 operator under a refined view that considers N2 as a monotonic logic which allows us to expand our understanding of answer sets. Moreover, N2 helped us to derive an alternative definition of ⊕1 avoiding the use of unnecessary extra atoms.
Differenzialdiagnose rasch progredienter Demenzen
Authors: Heinemann Uta , Gloeckner Friderike , Varges Daniela , Meissner Bettina , Krasnianski Anna , Zerr Inga
Published: June 2007

Zusammenfassung: Die Symptomatik “Demenz” kann durch eine Vielzahl zugrunde liegender Erkrankungen begründet sein. Dabei ist es von besonderer Bedeutung, potenziell reversible Erkrankungen zu erkennen. In dieser Arbeit werden Patienten mit einer rasch progredienten Demenz analysiert, die dem Nationalen Referenzzentrum für Spongiforme Enzephalopathien in Göttingen gemeldet worden sind. Ein hoher Anteil von 35 % litt an potenziell reversiblen Erkrankungen, insbesondere entzündlichen und autoimmunen Erkrankungen. Unter den nicht-reversiblen Erkrankungen stand der M. Alzheimer erwartungsgemäß im Vordergrund. Potenziell reversible Erkrankungen wiesen ein jüngeres Alter bei Erkrankungsbeginn und eine tendenziell kürzere Krankheitsdauer auf. Unter den neurodegenerativen Erkrankungen waren die Patienten vorwiegend homozygot für Methionin in Bezug auf den Polymorphismus am Codon 129 des Prionprotein Gens (PRNP). Dieser Befund ist in der Literatur als Risikofaktor für die Creutzfeldt-Jakob-Erkrankung und den M. Alzheimer beschrieben. Die Studie umfasste ebenfalls ein Analyse der gängigsten neurodegenerativen Marker Gesamttau, β-Amyloid1-42, neuronenspezifische Enolase (NSE) und S100B. Dabei zeigten sich Unterschiede zwischen den Krankheitsgruppen für Tau und S100B, während β-Amyloid1-42 bei allen erniedrigt und NSE bei allen Patienten im Normbereich war. Daneben wurde ein innovativer Marker zur Verbesserung der Liquordiagnostik untersucht. Erniedrigte Transthyretin-Werte halfen bei der Differenzierung zwischen M. Alzheimer und gesunden Kontrollen, aber auch in Abgrenzung zu anderen neurodegenerativen Erkrankungen. Zusammenfassend kann die Darstellung klinischer Daten und etablierter und innovativer Liquormarker die Differenzialdiagnostik von Demenzen verbessern. Daneben werden seltene behandelbare Demenzursachen, die Hashimoto-Encephalopathie und die progressive Encephalopathie mit Rigor und Myoklonien (PERM), sowie ein Vorschlag zur Differenzialdiagnostik rasch progredienter Demenzen dargestellt.
Evidenzbasierte neuropsychologische Therapie in der neurologischen Frührehabilitation von komatösen und apallischen Patienten
Authors: Heindorf Ralf , Müller Sandra Verena , Zieger Andreas
Published: June 2007

Zusammenfassung: Neurologische Frührehabilitation ist ein spezielles Tätigkeitsgebiet für Neuropsychologen, in dem sich die klassischen neuropsychologischen Methoden kaum oder gar nicht anwenden lassen. Die Behandlung von Patienten mit schweren Störungen der Bewusstheit für sich und/oder die Umwelt bedarf einer individuellen und auf die verbliebenen Fähigkeiten des Patienten gerichteten Herangehensweise. Es kann gezeigt werden, dass spezielle diagnostische Ansätze in der Frührehabilitation als evidenzbasiert angesehen werden können. Die eingesetzten Verfahren bekommen jedoch nur in der individuellen Anpassung an die Fähigkeiten des Patienten und im Austausch mit dem interdisziplinären Team ihre diagnostische Aussagekraft. Für die therapeutischen Ansätze multisensorische Stimulation und Kommunikationsaufbau sind ebenfalls positive Effekte nachweisbar, eine gruppenstatistische Evidenzbasierung erscheint jedoch aufgrund der methodischen und ethischen Rahmenbedingungen nicht sinnvoll.
Evidenzbasierung in der Psychotherapie
Authors: Lutz Wolfgang
Published: June 2007

Zusammenfassung: Patientenorientierte Psychotherapieforschung (patient-focused psychotherapy research) oder auch Qualitätsmanagement in der Psychotherapie können als relativ neue Ansätze in der sich immer wieder entfachenden Debatte um eine praxisrelevante Evaluation psychotherapeutischer Tätigkeit sowie die Evidenzbasierung von Psychotherapie angesehen werden. In vielen psychotherapeutisch arbeitenden Institutionen wird routinemäßig eine psychometrische Evaluation der psychotherapeutischen Behandlung durchgeführt, um die klinische Fallkonzeption zu Therapiebeginn zu unterstützen sowie die Resultate bei Therapieabschluss zu evaluieren. Neuere Konzepte und Methoden der patientenorientierten Psychotherapieforschung erlauben eine weitergehende Verwendung der Patientenausgangs-, Verlaufs- und Abschlussdokumentationen zur empirischen Unterstützung der differenziellen wie adaptiven Indikation. Dieser Beitrag diskutiert sowohl wissenschaftliche als auch klinisch-praktische Aspekte einer patientenorientierten Psychotherapieforschung und damit einer verstärkten Evidenzbasierung von Psychotherapie anhand von Beispielstudien.
Multi‐point observations of the Hall electromagnetic field and secondary island formation during magnetic reconnection
Authors: Eastwood J. P. , Phan T.‐D. , Mozer F. S. , Shay M. A. , Fujimoto M. , Retinò A. , Hesse M. , Balogh A. , Lucek E. A. , Dandouras I.
Published: June 2007

A key feature of collisionless magnetic reconnection is the formation of Hall magnetic and electric field structure in the vicinity of the diffusion region. Here we present multi‐point Cluster observations of a reconnection event in the near‐Earth magnetotail where the diffusion region was nested by the Cluster spacecraft; we compare observations made simultaneously by different spacecraft on opposite sides of the magnetotail current sheet. This allows the spatial structure of both the electric and magnetic field to be probed. It is found that, close to the diffusion region, the magnetic field displays a symmetric quadrupole structure. The Hall electric field is symmetric, observed to be inwardly directed on both sides of the current sheet. It is large (∼40 mV m−1) on the earthward side of the diffusion region, but substantially weaker on the tailward side, suggesting a reduced reconnection rate reflected by a similar reduction in Ey. A small‐scale magnetic flux rope was observed in conjunction with these observations. This flux rope, observed very close to the reconnection site and entrained in the plasma flow, may correspond to what have been termed secondary islands in computer simulations. The core magnetic field inside the flux rope is enhanced by a factor of 3, even though the lobe guide field is negligible. Observations of the electric field inside the magnetic island show extremely strong (∼100 mV m−1) fields which may play a significant role in the particle dynamics during reconnection.
Energy filter effect for solar wind particle entry to the plasma sheet via flank regions during southward interplanetary magnetic field
Authors: Zhou X.‐Z. , Pu Z. Y. , Zong Q.‐G. , Xie L.
Published: June 2007

Several mechanisms have been used to explain solar wind plasma entry into the plasma sheet in the magnetotail. In this paper, we focus on the gradient drift entry (GDE) process in the equatorial flanks of the magnetosphere, based on the magnetopause picture of a tangential discontinuity with a small tangential electric field as was suggested by Alfvén (1968). We discuss the GDE efficiency in different conditions using the adiabatic theory. It can be clearly shown that the GDE efficiency is much lower during southward interplanetary magnetic field (IMF), with a strong energy filter effect for incoming solar wind particles. Given a typical condition, a critical energy for particle entry is calculated to be several kiloelectron volts. Only those particles with higher energy can penetrate the magnetopause, a condition which can be also proved by test particle simulations. The lower efficiency than that during northward IMF during periods of southward IMF is in agreement with the different properties of the plasma sheet observed, i.e., hot and tenuous when the IMF is southward, cold and dense for northward IMF.
Secondary indirect effects in gravity anomaly data inversion or interpretation
Authors: Vajda P. , Vaníček P. , Novák P. , Tenzer R. , Ellmann A.
Published: June 2007

The application of topographic corrections to gravity anomalies and disturbances, and their use in formulating and solving the gravimetric inverse problem are reinvestigated. The gravity anomaly, whose definition is based on the disturbing potential by means of the fundamental gravimetric equation, rather than by the vertical derivative of the disturbing potential, differs from the gravity disturbance, which also has implications to the application of the topographic correction. We demonstrate that the application of the topographic correction to the gravity anomaly gives origin to the secondary indirect topographic effect (SITE) and that the formulation of a rigorous relation between the attraction of anomalous subsurface mass density distribution and the gravity anomaly gives rise to a secondary indirect effect of the anomalous mass density distribution (SIEAM). The SITE is shown to be numerically significant in mountainous areas, where it can reach 100 mGal. Because of secondary indirect effects, the gravity anomaly in its rigorous sense is not well suited for the gravimetric inversion. Instead, the topo‐corrected gravity disturbance best fits the needs of gravity data inversion or interpretation, as it exactly matches the attraction of the Earth's subsurface anomalous density distribution. It is pointed out that, in geophysics, the gravity data used for inversion or interpretation, although called the “Bouguer gravity anomaly,” even if preceded by the adjective “ellipsoidal” as by the newly proposed standards for the North American database, are by the standards of rigor the “topographically corrected gravity disturbance.”
Asymptotic behavior of frequency and wave number spectra of nearshore shoaling and breaking waves
Authors: Kaihatu James M. , Veeramony Jayaram , Edwards Kacey L. , Kirby James T.
Published: June 2007

Wave number spectra from shoaling and breaking waves in five laboratory tests are compared to a recently published parameterization describing the evolutionary characteristics of surf zone wave spectra. This parameterization proposes two regions in which different wave number spectral shapes are present; the Zakharov range (2.5 kp ≤ k ≤ 1/h) has a k−4/3 dependence, while the Toba range (k > 1/h) has a k−5/2 shape. Comparison to laboratory data reveals that the spectral slopes from the Zakharov range of the data trend toward increased agreement with the parameterization in the range of incipient breaking. In contrast, the spectral slopes from the Toba range evolve slowly, likely owing to nonlinear interactions with lower, more energetic wave numbers. However, in the inner surf zone the spectral shape for both parameterized ranges tend toward k−2 (or equivalently, f−2 in shallow water). The dissipation coefficient α(f) is extracted from time series of free surface elevations; it is found that α(f) has a reciprocal frequency dependence with that of the frequency spectra S(f) of the data, and that this correspondence increases as the waves enter the surf zone. Additionally α(f) ∼ 1/S(f) ∼ f2 in the inner surf zone. It is concluded that the wave number spectrum parameterization, particularly in the Zakharov range, reasonably describes the spectral shape while the surf zone is still only partially saturated. However, continued breaking moves the spectral shape away from the parameterized slope toward a f−2 (or k−2) spectral shape, representative of the sawtooth‐like shape of surf zone waves. This spectral shape is a clear inner surf zone asymptote.
A process‐oriented regression model for column ozone
Authors: Wohltmann I. , Lehmann R. , Rex M. , Brunner D. , Mäder J. A.
Published: June 2007

Multiple regression models for time series of ozone column measurements have been a standard tool of atmospheric sciences for decades. We propose a new model, which is based on a process‐oriented approach and captures all major processes relevant to the change of stratospheric ozone column. These are assumed to be short‐ and long‐term changes by tropospheric and stratospheric pressure systems, the residual circulation, homogeneous and heterogeneous halogen chemistry, aerosols, the quasi‐biennial oscillation (QBO), and the solar cycle. Daily ozone data are taken from 49 stations of the Dobson photometer network covering polar, middle, and equatorial latitudes. A focus is placed on dynamical changes in midlatitudes. Results show that the trend in ozone column between 1970 and 2003 is dominated by halogen chemistry in midlatitudes (up to −1.4 ± 0.5 DU/year or −4.1%/decade in winter) but that there are also significant trends of other origin in some regions of the world. These trends are mainly caused by changes in horizontal advection and convergence or divergence of mass, which are both related to trends in tropospheric and lower stratospheric pressure systems like the Icelandic low (represented by a proxy based on a vertically integrated equivalent latitude profile). This dynamical contribution to the trend depends both on month and longitude and varies between −0.7 ± 0.2 DU/year (−1.9%/decade) and 0.4 ± 0.2 DU/year (1.1%/decade). Another influence on trends in midlatitudes is dilution of polar vortex air (described by a proxy based on the volume of polar stratospheric clouds). The trend in the dilution proxy reaches up to −0.2 ± 0.15 DU/year (−0.6%/decade) in all midlatitude regions during late spring.
Foam droplets generated from natural and artificial seawaters
Authors: Tyree Corey A. , Hellion Virginie M. , Alexandrova Olga A. , Allen Jonathan O.
Published: June 2007

Submicrometer sea salt aerosol (SSA) particles are routinely observed in the remote marine boundary layer (MBL); these aerosols include cloud condensation nuclei and so affect the earth's radiative balance. Here foams designed to mimic oceanic whitecaps were generated in the laboratory using a range of bubbling flow rates and aqueous media: unfiltered seawater, filtered seawater, artificial seawater, and mixtures of filtered and artificial seawater. The number and sizes of dried foam droplets in the particle diameter, Dp, range 15–673 nm were measured. Particle size distributions for natural and artificial seawaters were unimodal with a dN/d logDp mode at Dp ≈ 100 nm (≈200 nm at 80% RH). The foam droplet mode falls within the range of reported mode diameters (Dp = 40–200 nm) for submicrometer SSA particles observed in the remote MBL. The present laboratory results were scaled up to estimate submicrometer SSA particle fluxes; this extrapolation supports the hypothesis that foam droplets are the most important source of SSA particles by number. The foam droplet flux from the oceans was estimated to be 980 cm−2 s−1 for a fractional white cap coverage, W, of 0.2%. These results compared well with foam droplet fluxes reported elsewhere. The origins of variability in foam droplet fluxes were also evaluated. Natural organic matter affected foam droplet flux by a factor of 1.5; this was less than (1) the effect of bubbling flow rate on foam droplet flux (factor of 5) and (2) the uncertainty in W (factor of 3–7).
Formation of the double rift system in the Thaumasia Highlands, Mars
Authors: Grott M. , Kronberg P. , Hauber E. , Cailleau B.
Published: June 2007

The Thaumasia Highland Rifts are two complex graben structures in the Thaumasia Highland belt, located in the southern Thaumasia region, Mars. The rifts are arranged 90–130 km apart in a nearly subparallel setting and represent a very unusual style of crustal deformation. We have investigated the mechanism responsible for this peculiar style of rifting and found strain localization by volcanic weak zones to be a major factor for fault‐pattern formation, indicating widespread prerift and synrift volcanic activity in the region. This result is consistent with the high heat flow during rift emplacement as estimated from rift flank uplift. Our results indicate that the onset of volcanism predates the rift formation process and that magmatism and the associated lithospheric weak zones control the rift locations. The simulations performed here are in good agreement with the observations for extension in the NW–SE to NNW–SSE direction, and we favor a formation scenario involving passive rifting in a magmatectonically active environment.
New sites of Australasian microtektites in the central Indian Ocean: Implications for the location and size of source crater
Authors: Prasad M. Shyam , Mahale Vasudev P. , Kodagali V. N.
Published: June 2007

We have identified 15 new Australasian microtektite sites along a transect roughly N‐S in the central Indian Ocean. These locations, in addition to the existing 46 sites, total to 61 microtektite sites in the oceans. We carried out regression analysis of a selected area between 12–26°N and 98–112°E, at 0.5° intervals using three microtektite data sets separately: 41 sites, 46 sites (number of sites known up to the years 1994 and 2006, respectively), and the entire data set of 61 sites. This area was chosen because, on the basis of various lines of evidence, several investigators suggested impact craters for the strewn field within this broad area. The 41 site data set defines an impact site at about 12°N and 106°E. Whereas the contours joining the highest values of the square of the correlation coefficient by using 46 site and 61 site data sets define an area located in NE Thailand–central Laos, the center of this site is at 18°N and 104°E. Therefore with progressive increase in microtektite data the location of the impact site seems to get defined more rigorously. On the basis of the equations for the concentration of the ejecta and the distance from the source region, the calculated crater size has a diameter range between 33 and 120 km. Interestingly, the lower size limit of 33 km has been found closer to ground truth by verification from the microtektite data of the Ivory Coast strewn field.
Timing and patterns of debris flow deposition on Shepherd and Symmes creek fans, Owens Valley, California, deduced from cosmogenic 10Be
Authors: Dühnforth Miriam , Densmore Alexander L. , Ivy‐Ochs Susan , Allen Philip A. , Kubik Peter W.
Published: June 2007

Debris flow fans on the western side of Owens Valley, California, show differences in their depths of fan head incision and thus preserve significantly different surface records of sedimentation over glacial‐interglacial cycles. We mapped fan lobes on two fans (Symmes and Shepherd creeks) on the basis of the geometry of the deposits using field observations and high‐resolution airborne laser swath mapping data and established an absolute fan lobe chronology by using cosmogenic radionuclide exposure dating of large debris flow boulders. While both fans and their associated catchments were subject to similar tectonic and base level conditions, the Shepherd Creek catchment was significantly glaciated while that of Symmes Creek experienced only minor glaciation. Differences in the depth of fan head incision have led to cosmogenic surface age chronologies that differ in the length of the preserved depositional records. Symmes Creek fan preserves evidence of exclusively Holocene deposition with cosmogenic 10Be ages ranging from 8 to 3 ka. In contrast, the Shepherd Creek fan surface was formed by late Pleistocene and Holocene debris flow activity, with major deposition between 86–74, 33–15, and 11–3 ka. These age constraints on the depositional timing in Owens Valley show that debris flow deposition in Owens Valley occurred during both glacial and interglacial periods but may have been enhanced during marine isotope stages 4 and 2. The striking differences in the surface record of debris flow deposition on adjacent fans have implications for the use of fan surfaces as paleoenvironmental recorders and for the preservation of debris flow deposits in the stratigraphic record.
Mechanics of river mouth bar formation: Implications for the morphodynamics of delta distributary networks
Authors: Edmonds D. A. , Slingerland R. L.
Published: June 2007

In this paper, we use observational data and numerical modeling to present a new explanation for the formation of river‐dominated delta networks. Observational data from deltas throughout the world show that distributary channel widths, depths, and lengths decrease nonlinearly with successive bifurcations. Trends in width and depth are an outcome of hydraulic geometry scaling. The trend in channel length is a consequence of delta growth. Analyses of serial maps show that the positions of bifurcations are the fossilized locations of river mouth bars (also called middle‐ground and distributary mouth bar) in front of old delta channel mouths. Therefore the trend in channel length can be explained through the mechanics of river mouth bar formation and evolution. We use Delft3D, a coupled hydrodynamic and morphodynamic model, to simulate the process of river mouth bar formation within an expanding turbulent jet in front of distributary channel mouths. Our results describe in detail the formation and evolution of a river mouth bar system and demonstrate that the distance to the river mouth bar is proportional to jet momentum flux and inversely proportional to grain size. Therefore channel length decreases down delta because with each successive bifurcation, the jet momentum flux decreases. These results can be used to predict the future evolution of river‐dominated deltas and can be used to aid in hydrocarbon exploration of these depositional environments.
Evaluating a high‐resolution climate model: Simulated hydrothermal regimes in frozen ground regions and their change under the global warming scenario
Authors: Saito Kazuyuki , Kimoto Masahide , Zhang Tingjun , Takata Kumiko , Emori Seita
Published: June 2007

An atmosphere‐ocean‐land coupled global climate model at high horizontal resolution (∼0.5° land mesh) with a five‐layer, 4.0 m deep soil was evaluated as a tool to simulate changes in the distribution of frozen ground and subsurface hydrothermal regimes under the global warming scenario. The land scheme explicitly treats soil freezing/thawing processes, surface energy exchange, and water fluxes, including snow cover effects. Modeled soil temperature showed large cold biases in the cold seasons, especially in high latitudes, which likely resulted from shallow and simplified soil column with zero heat flux condition at the bottom and insufficient snow representation. Two types of frozen ground were classified according to monthly soil temperatures: “permafrost” for regions with the maximum active layer thickness less than 4 m and “seasonally frozen ground.” Simulated present‐day (1980–1999) distribution is in good agreement with observational estimates for both. Under climatic warming forcing, projected change in land and subterranean hydrothermal regimes shows amplification in higher latitudes. Approximately 60% of the present‐day permafrost regions would degrade into seasonally frozen ground by 2100. In the circum‐Arctic basins, increased precipitation would lead to a 13.7% increase in freshwater discharge into the Arctic Ocean. The limitations of the current model configuration and the implied reliability of the results are discussed, and the future improvements and potentials of such modeling approach are also presented. A medium‐resolution (∼2.8° mesh) ensemble produces qualitatively similar results for the hydrothermal regimes in the cold regions, although some local features were inevitably smoothed out, giving different quantitative estimates.
Scenario workshops: A useful method for participatory water resources planning?
Authors: Hatzilacou Dionyssia , Kallis Giorgos , Mexa Alexandra , Coccosis Harris , Svoronou Eleni
Published: June 2007

This article reports on a scenario workshop (SW) for water resources management at the island of Naxos, Greece. The workshop was part of a European research project studying the advantages and limitations of different participatory methods in the context of the Water Framework Directive. It involved policy makers, scientists, business representatives, and citizens from different parts of the island. On the first day, participants worked to envision a sustainable development future for the island and its water resources. Discussion was inspired by four alternative water development scenarios prepared by the organizers. Participants' vision statements emphasized a diversified development path and balanced water solutions. On the second day, participants worked to plan the actions needed to realize their common vision. The SW turned out to be a good method to initiate a multipartner dialogue, to include new stakeholders in the water policy debate, and to a certain extent, to promote learning between participants. On the other hand, it did not appear well suited to resolve conflicts and aid decisions in the face of scientific complexity and uncertainty. SW seems to be a good method for the “upstream,” preparatory, capacity‐building tasks of a planning process but not for the production of substantive decision outputs such as consensual agreements or action plans. The Naxos experiment also raised the centrality of framing, participant selection, and facilitation in participatory processes.
Soil moisture variations and ecosystem‐scale fluxes of water and carbon in semiarid grassland and shrubland
Authors: Kurc Shirley A. , Small Eric E.
Published: June 2007

Soil moisture distribution emerges as a key link between hydrologic and ecologic processes in semiarid grassland and shrubland, as it influences evapotranspiration, respiration, and assimilation. In support, we present three years of data (2002–2004) collected from a semiarid grassland and shrubland within the Sevilleta National Wildlife Refuge of central New Mexico; the two sites are separated by about 5 km. Instrumentation includes an eddy covariance tower and typical micrometeorological devices at both locations. Additionally, the grassland site features six soil moisture profiles and the shrubland site features four soil moisture profiles, with the maximum depth at 52.5 cm. At both sites, most rain falls during the warm season, but large storms do occur at other times of the year, e.g., spring of 2004. Soil moisture pulses at 2.5 cm follow almost all rain events, whereas only four pulses in the 3‐year record are observed at 52.5 cm in the grassland and two in the shrubland; these deeper pulses follow large precipitation events or a series of smaller events. The daily times series of evapotranspiration (ET) is similar between the grassland and shrubland, supporting the results of Kurc and Small (2004). ET variations largely reflect changes in the soil moisture at 2.5 cm. In contrast, though the daily time series of net ecosystem exchange (NEE) at both sites covary, the magnitudes of peaks in net negative ecosystem exchange (NEE−) and net positive ecosystem exchange (NEE+) are over twice the magnitude at grassland than at the shrubland. Furthermore, pulses associated with NEE− peaks last much longer than ET pulses, of the order of 1–2 months, without any particular adherence to the climatologically defined rainy season. These NEE− pulses reflect changes in deeper soil moisture, i.e., 52.5 cm at the grassland and 37.5 cm at the shrubland. Finally, evidence of soil moisture driven respiration is found throughout the NEE time series, with spikes of NEE+ following most rain events; however, longer periods of NEE+ also occur during relatively dry periods. Modeled assimilation suggests that the relationship between assimilation and soil moisture is strongest at depths at least 30 cm below the surface.