bluuebunny/crossref_metadata_2025 huggingface dataset:
Charge‐Transport Behavior in Shape‐Controlled Poly(3,4‐ethylenedioxythiophene) Nanomaterials: Intrinsic and Extrinsic Factors
Authors: Yoon Hyeonseok , Hong Jin‐Yong , Jang Jyongsik
Published: September 2007

The charge‐transport behavior in one‐dimensional (1D) poly (3,4‐ethylenedioxythiophene) (PEDOT) nanomaterials of three different shapes is described. Both intrinsic and extrinsic factors are considered from the viewpoint of a single nanoparticle and nanoparticle assembly. Intrinsically, the oxidation level of the 1D PEDOT nanomaterials becomes higher with increasing aspect ratio of the nanomaterials, which is closely linked to the conjugation length. This result implies that the transport properties of the nanomaterials are significantly dependent on their shape. Extrinsically, the 1D PEDOT nanomaterials make an ohmic contact with gold interdigitated microelectrodes. In addition, a strong correlation is observed between the interparticle contact resistance and the shape of the nanomaterials. Lastly, the intrinsic and extrinsic factors related to charge transport are further illustrated by the resistance changes of nanomaterial‐based chemical sensors. As a result, judicious tailoring of the dimensional and geometrical characteristics of the conducting‐polymer nanomaterials may enable precise control over their transport properties as well as the characteristics of the nanomaterial‐based devices.
Comparing and evaluating computer graphics and visualization software
Authors: Laramee Robert S.
Published: September 2007

When starting a new computer graphics or visualization software project, students, researchers, and businesses alike must decide whether or not to start from scratch or with third‐party software. Since computer graphics and visualization applications are typically quite large, developers often build upon existing software libraries in order to take advantage of the tens of thousands of hours worth of development and testing already invested. Thus, developers and managers must face the decision of which library to build on. We present a side‐by‐side comparison and evaluation of four popular, state‐of‐the‐art visualization and computer graphics libraries, namely the Visualization Toolkit (VTK), Open Inventor, Coin3D, and Hoops 3D. The evaluation is based on the feature set, ease of installation, development of a benchmark application, documentation, and technical support for each package. The results of our comparison and evaluation are described and recommendations are given as for whom the libraries are best suited. The VTK prevails on top in many of the aspects we compared and evaluated. Copyright © 2007 John Wiley & Sons, Ltd.
e‐Portfolios: Concepts, designs, and integration within student affairs
Authors: Garis Jeff W.
Published: September 2007

This chapter provides an overview of e‐portfolio concepts and designs. It describes a model that outlines an array of dimensions for the categorization of e‐portfolio systems, reviews selected systems, and makes observations regarding the importance for student affairs units to understand, collaborate, and include e‐portfolio systems within their programs and services.
e‐Portfolios: A collaboration between student affairs and faculty
Authors: Johnson Glenn , Rayman Jack R.
Published: September 2007

This chapter describes how a commitment to instructional design principles has prompted the evolution of collaborative interaction between student affairs professionals and academic faculty. Central to this collaboration are the opportunities that e‐portfolios have made available.
Enhancing learning and assessment through e‐portfolios: A collaborative effort in Connecticut
Authors: Goldsmith Diane J.
Published: September 2007

The Connecticut Distance Learning Consortium and thirty‐one institutional partners are using e‐portfolios for a wide variety of learning and assessment purposes.
Development and implementation of an e‐portfolio as a university‐wide program
Authors: Lumsden Jill A.
Published: September 2007

This chapter describes the development of a successful e‐portfolio system, with over forty‐seven thousand users within five years of implementation and how it has been integrated as a university‐wide program.
Adaptation of the career portfolio at the University of California, San Diego: A case study
Authors: Ceperley Andrew , Schmidt Craig
Published: September 2007

This chapter describes the planning, development, testing, and launching phases of UCSD's online career portfolio, as well as a summary of its impact and discussion of its future.
Concluding observations and implications of e‐portfolios for student affairs leadership and programming
Authors: Dalton Jon C.
Published: September 2007

This chapter provides an overview of the preceding chapters and concluding observations and recommendations.
Selective trellis pruning for block codes: theory and application to iterative decoding
Authors: Bertrand Eric , Labeau Fabrice
Published: September 2007

In this paper we present a new method to simplify trellis‐based decoding of linear block codes. Our method is based on removing (pruning) some edges and states from the trellis representation of the code; the trellis is pruned through some hard‐decisions that are made on received bits whose likelihood exceeds a predefined threshold. We show in this paper how this simplification can be accounted for by a new generator matrix (and sometimes a coset leader) that totally parametrize the new trellis, or, equivalently, the set of allowed codewords after simplification. Extensive simulations show that significant computational savings can be achieved, at a very small loss in coding performance, as long as the operating point and threshold are carefully chosen. Moreover, the application of this technique to iterative decoding of product codes is outlined, and our results show that the simplifications do not hinder the convergence, again, as long as proper parameters are chosen. Copyright © 2007 John Wiley & Sons, Ltd.
A functional analysis of KlSRB10: implications in Kluyveromyces lactis transcriptional regulation
Authors: Núñez Laura , González‐Siso Isabel , Rodríguez‐Belmonte Esther , Soengas Pilar , Lamas‐Maceiras Mónica , Cerdán Maria Esperanza
Published: September 2007

The function of KlSRB10 has been studied by diverse approaches. Primer extension analysis reveals several transcription start sites, position − 17 from ATG being predominant. Deletion of KlSRB10 diminishes growth in ethanol and decreases KlCYC1 transcript levels. A second phenotype associated with this deletion affects growth in galactose. These phenotypes are independent of the specific sequence connecting the ATP binding cassette and the kinase domain of Srb10p in yeasts. KlSrb10p is not necessary for LAC4 repression mediated by KlGal80p, as deduced by construction of a Klgal80Δsrb10Δ double mutant. In the two‐hybrid system, KlSrbp10p interacts with the protein encoded by KLLA0E08151g (KlSrbp11p). Copyright © 2007 John Wiley & Sons, Ltd.
Radiofrequency (RF)‐Assisted Hepatectomy May Induce Severe Postoperative Liver Damage
Authors: Mitsuo Miyazawa , Takahiro Torii , Yasuko Toshimitsu , Masayasu Aikawa , Katsuya Okada , Nozomi Shinozuka , Yoshihide Otani , Isamu Koyama
Published: September 2007

Background

Radiofrequency (RF) ablation for the treatment of the section line prior to liver resection has been proposed as a way to reduce blood loss during hepatectomy. Our group compared hepatectomy with and without RF ablation to determine whether this technique actually reduces blood loss during liver resection and whether it affects the perioperative outcome.

Method

Of 151 patients who underwent a hepatectomy between January 2002 and October 2005 at the Division of Gastrointestinal Surgery in the Department of Surgery of Saitama Medical University, 48 who had a partial hepatectomy or resection of a portion of liver smaller than a single Couinaud segment were included in the study. Twenty patients who had RF‐assisted hepatectomy [RF (+) group] and 28 patients who had hepatectomy without ablation [RF (‐) group] were studied to compare the rates of intraoperative blood loss and the effects of RF ablation on the perioperative outcome.

Results

Intraoperative blood loss was significantly reduced in the RF (+) group. In contrast, the alanine aminotransferase activity in the RF (+) group was significantly elevated immediately after the operation. There was no significant difference in the incidence of postoperative complications between the groups, although bile leakage did occur in three RF (+) patients.

Conclusions

Our results demonstrate that the RF ablation technique can be a useful way to reduce surgical blood loss. In view of its association with severe postoperative liver damage, the technique must be applied with caution. The danger may be especially relevant to patients with chronic liver disease and decreased liver reserve.
Clinical Significance of Perioperative Immunonutrition for Patients with Esophageal Cancer
Authors: Takeuchi Hiroya , Ikeuchi Shunji , Kawaguchi Yoshiki , Kitagawa Yuko , Isobe Yoh , Kubochi Kiyoshi , Kitajima Masaki , Matsumoto Sumio
Published: September 2007

Background

We hypothesized that preoperative and/or postoperative enteral immune‐enhanced formulas that are supplemented with arginine, omega‐3 fatty acids, and RNA may reduce postoperative complications in patients undergoing esophagectomy for thoracic esophageal squamous cell carcinoma (ESCC).

Methods

Forty patients who underwent esophagectomy were divided into three groups: group A (n = 20) received a control enteral diet (Erental) through the jejunostomy after surgery. group B (n = 6) received an enteral diet supplemented with immune‐enhancing substrates (Impact) containing arginine, omega‐3 fatty acids, and RNA after surgery. group C (n = 14) received the impact before and after surgery.

Results

Lymphocyte counts in group C on postoperative day (POD) 7 were somewhat higher than that in group A (p = 0.07) and significantly higher than in group B (p = 0.03). Furthermore the incidence of incisional wound infection in group C was significantly lower than that in group A (p = 0.03). Moreover, the duration of postoperative systemic inflammatory response syndrome (SIRS) was significantly shorter in group C than in group A (p < 0.05).

Conclusions

This study reveals that the perioperative immune‐enhanced formula may be superior to postoperative control enteral formulas in terms of reducing surgical wound infection and postoperative SIRS, which may result in serious postoperative complications for patients who have undergone esophagectomy.
Selection of breeding territory by little bustard (Tetrax tetrax) males in Central Spain: the role of arthropod availability
Authors: Traba Juan , Morales Manuel B. , García de la Morena Eladio L. , Delgado María‐Paula , Krištín Anton
Published: September 2007

The influence of arthropod availability on the formation of male little bustard breeding territories in central Spain was studied in two consecutive years. Arthropods (68,217 individuals) were sampled using pitfall trapping and male territories estimated by means of kernel functions. Hymenopterans (ants), beetles, mites and spiders were the main taxa found in the samples, while the highest contributions in terms of biomass came from hymenopterans, beetles and orthopterans. The only group that exhibited significant biomass differences between territory and non‐territory locations was that of the beetles; this pattern was consistent between years. Carabidae was the main beetle family in terms of biomass, followed by other large beetles such as Tenebrionidae, Cleridae, Scarabeidae and Elateridae. The biomass of Carabidae that were larger than 15 mm was significantly higher within territories than outside them. The biomass of Cleridae was greater in fallows, while Elateridae were more abundant in arable fields. The total biomass of beetles that were larger than 15 mm was higher in arable fields than in fallows. Family richness differed between years, while diversity showed differences between agricultural fields (it was highest in fallows), although these variables did not differ between territory and non‐territory locations. Results indicate that large beetles (particularly carabids) seem to be a valuable food resource that is defended by little bustard males during the highly energy‐demanding breeding season, which is discussed here in relation to habitat selection, the mating system and its implications for the conservation of the species.
Newton Algorithms for Analytic Rotation: an Implicit Function Approach
Authors: Boik Robert J.
Published: September 2007

In this paper implicit function-based parameterizations for orthogonal and oblique rotation matrices are proposed. The parameterizations are used to construct Newton algorithms for minimizing differentiable rotation criteria applied to m factors and p variables. The speed of the new algorithms is compared to that of existing algorithms and to that of Newton algorithms based on alternative parameterizations. Several rotation criteria were examined and the algorithms were evaluated over a range of values for m. Initial guesses for Newton algorithms were improved by subconvergence iterations of the gradient projection algorithm. Simulation results suggest that no one algorithm is fastest for minimizing all criteria for all values of m. Among competing algorithms, the gradient projection algorithm alone was faster than the implicit function algorithm for minimizing a quartic criterion over oblique rotation matrices when m is large. In all other conditions, however, the implicit function algorithms were competitive with or faster than the fastest existing algorithms. The new algorithms showed the greatest advantage over other algorithms when minimizing a nonquartic component loss criterion.
Role of carbohydrate moiety of bleomycin‐A2 in caspase‐3 activation and internucleosomal chromatin fragmentation in apoptosis of laryngeal carcinoma cells
Authors: Brahim Souhir , Abid Kaouthar , Kenani Abderraouf
Published: September 2007

Bleomycin (BLM), an antitumor antibiotic, is currently used during anticancer therapy. The therapeutic efficiency of BLM for the treatment of malignant tumors is related to its ability to cleave DNA. However, little is known about the biological activity of the glycannic moiety in BLM‐induced cytotoxicity. In this study, cell death induced by BLM‐A2 and deglycosylated BLM‐A2 was studied in a laryngeal carcinoma cell line (HEp‐2 cells). Our results indicate that HEp‐2 cells showed morphological and biochemical changes associated with apoptosis in the presence of low concentrations of BLM‐A2. In contrast, the same changes, except activation of caspase‐3 and internucleosomal digestion of genomic DNA, were observed when cells were exposed to high concentrations of deglycosylated BLM‐A2. These observations indicate that the glycannic moiety from the bleomycin molecule has important biological effects on the cytotoxicity of the drug.
Evaluation of the efficacy of subcutaneous carbon dioxide insufflations for treating acute non specific neck pain in general practice: A sham controlled randomized trial
Authors: Brockow Thomas , Heißner Thomas , Franke Annegret , Resch Karl‐Ludwig
Published: September 2007

Background: Subcutaneous carbon dioxide insufflations are a safe and inexpensive treatment modality in complementary medicine and are used mainly in musculoskeletal pain and vascular conditions. However, no rigorous trial exists on their efficacy.

Aims: To evaluate whether patients with acute non specific neck pain get pain free sooner, if treated with subcutaneous carbon dioxide insufflations compared to sham ultrasound.

Methods: One hundred and twenty‐six persons from one German general practice with acute non specific neck pain less than 7 days and a current pain intensity ≥40mm on a 100mm visual analogue scale were included into the trial. Participants received either a maximum number of nine subcutaneous carbon dioxide insufflations or a maximum number of nine sham ultrasound administered by four therapists in a randomized order, thrice weekly. Main outcome measure was time to neck pain relief during a 28 days follow‐up period from baseline analyzed by intention to treat.

Results: Twenty‐seven of 63 patients (43%) got neck pain free in the subcutaneous carbon dioxide insufflations group compared to 29 of 63 (46%) in the sham ultrasound group. Median time to neck pain relief was 28 days in both groups (p=.77; logrank test). Secondary analyses yielded similar results.

Conclusions: The study indicates that subcutaneous carbon dioxide insufflations are not superior to sham ultrasound for treating patients with acute non specific neck pain. Because course of pain did not differ from the one expected from self limitation, it is likely that non specific effects played only a minor role, if any, in both interventions.
Molecular evolution and selection of a gene encoding two tandem microRNAs in rice
Authors: Wang Sheng , Zhu Qian-Hao , Guo Xingyi , Gui Yijie , Bao Jiandong , Helliwell Chris , Fan Longjiang
Published: September 2007

It has been shown that overexpression of MIR156b/c resulted in a bushy phenotype in maize and rice. Our results indicated that the MIR156b/c locus was highly conserved among cereals, but not in dicots and that genome duplication events played an important role in the evolution of the miR156 family. Genetic diversity investigation at the locus indicated that only ∼9% of nucleotide diversity observed in wild rice (O. rufigogon) was maintained in the cultivated rice and the neutral model was rejected (P
< 0.05) based on Tajima's D and Fu and Li's D
∗ and F
∗ tests. To our knowledge, this is the first example of miRNA gene to be targeted by both natural and domestication selection in plants.
Functional and profiling studies prove that prostate cancer upregulated neuroblastoma thymosin β is the true human homologue of rat thymosin β15
Authors: Dhaese S. , Jonckheere V. , Goethals M. , Waltregny D. , Vandekerckhove J. , Ampe C. , Van Troys M.
Published: September 2007

A peptide with a sequence identical to rat thymosin β(Tb)15 was reported to be upregulated in human prostate cancer. However, in this report we provide evidence that TbNB, initially identified in human neuroblastoma, is the only Tb isoform upregulated in human prostate cancer and that the Tb15 sequence is not present herein. In addition, we demonstrate that human TbNB has a higher affinity for actin in comparison to Tb4 and promotes cell migration. In combination, this experimentally validates TbNB as functional homologue of rat Tb15 in the human organism and clarifies the current composition of the human Tb family.
Animal models of neonatal stroke and response to erythropoietin and cardiotrophin‐1
Authors: Sola Augusto , Peng Hui , Rogido Marta , Wen Tong‐Chun
Published: September 2007

Neonatal stroke is increasingly recognized in preterm and term infants, and the rate of arterial ischemic infarction occurring around the time of birth is as high as the annual incidence of large‐vessel ischemic stroke in adults. Thus, neonatal stroke is a major contributor to perinatal morbidity and mortality, and a considerable number of these children will develop long‐term neurodevelopmental disabilities. Our ability to investigate this situation has been limited by the technical challenges in developing suitable animal models. Our objective is to describe recent evidence in relation to animal models of neonatal stroke. In addition, we review and report potential neuroprotective strategies specific to neonatal stroke, with a focus on erythropoietin and cardiotrophin‐1 because of their potential role in protection as well as repair.
Squash-preparation cytology from nasopharyngeal masses in the cat: cytological results and histological correlations in 30 cases
Authors: De Lorenzi Davide , Bertoncello Diana , Bottero Enrico
Published: September 2007

Upper airway obstruction in cats can be a life-threatening condition. Early recognition of clinical signs and an appropriate diagnostic approach increases the possibility of appropriate therapeutic choices. The purpose of this study was to assess the efficacy and diagnostic value of squash-preparation cytology in providing an accurate diagnosis of masses growing in the nasopharynx of cats. Cytological specimens prepared by a squash technique from nasopharyngeal masses in 30 cats were collected under direct endoscopic guidance and classified into four groups: benign inflammatory/hyperplastic mass, lymphoma, carcinoma and sarcoma. The cytopathological diagnosis was compared with the final histopathological diagnosis and indices of diagnostic test accuracy were calculated. The results showed good agreement between the cytological and histological diagnosis with a sensitivity of 0.94, a specificity of 0.81, a positive likelihood ratio of 0.9, a negative likelihood ratio of 0.9 and an overall accuracy of 0.9. Squash-preparation cytology is considered an accurate diagnostic tool for distinguishing benign from malignant nasopharyngeal masses in cats. For differentiation of lymphoma and lymphoid reactions histopathological confirmation is recommended.
Gender as a determinant of some nigerian adolescents' self‐concepts
Authors: Olowu A.A.
Published: September 2007

A review of some theories of sex identification in relation to self‐concept was attempted.

A self‐concept scale (Semantic differential) was administered on 264 boys and 108 girls. The ages range between 15·5 and 17·0 years with a mean of 16·7 years. The subjects were all Nigerians.

It was found that the boys had significantly (P<0·001) more positive self‐concepts than the girls on all the six self‐concept areas. The results were discussed in the light of psychological, physiological and social differences of the two groups. The socio‐cultural environment of the sample was taken into consideration in discussing the results.
Carbon isotope stratigraphy of the upper Telychian and lower Sheinwoodian (Llandovery–Wenlock, Silurian) of the Banwy River section, Wales
Authors: LOYDELL D. K. , FRÝDA J.
Published: September 2007

δ13Corg and TOC data are presented from the upper spiralis Biozone (Telychian, Llandovery, Silurian) through to the upper Sheinwoodian (Wenlock, Silurian) of the Banwy River section, Wales. In laminated hemipelagites from the Telychian, δ13Corg values rise through the upper lapworthi Biozone to a maximum in the lower insectus Biozone after which they decline slightly. The most conspicuous feature of the δ13Corg curve is the prolonged positive excursion in the Sheinwoodian, commencing in the upper murchisoni Biozone and ending in strata yielding Monograptus flexilis. This Sheinwoodian positive δ13C excursion in the Banwy River section correlates precisely with that recognized in the East Baltic. The interval with the highest δ13Corg values also records the highest TOC values, suggesting that for the Sheinwoodian at least burial of carbon may have contributed to the positive δ13C excursion. Bioturbated strata yield very low TOC values; whether the δ13Corg values from these beds reflect a primary signal or the result of biostratinomic or diagenetic modification is uncertain.
ABORTION INDEX AND MORTALITY OF OFFSPRING AMONG WOMEN OF DIFFERENT AGE, CASTE AND POPULATION GROUPS OF NORTH INDIAN MUSLIMS
Authors: ARA GULSHAN , SIDDIQUE YASIR HASAN , BEG TANVEER , AFZAL MOHAMMAD
Published: September 2007

The Muslims of Aligarh city are predominantly Sunnis, although there are also a considerable number of Shias. Among the Sunnis, approximately a quarter belong to Syed, Sheikh, Moghal and Pathan groups, and three-quarters belong to various lower biradaris. In the present study, 304 women attending the Primary Health Centre of the J. N. Medical College and Hospital, Aligarh Muslim University, Uttar Pradesh, were surveyed and the following recorded among Muslim women of high-rank (Ashraf) and low-rank (Ajlaf) castes: incidence of marriage, age of the mother at the time of marriage, present age of the mother, abortions, still births, pre-reproductive mortality and overall mortality. The Ashraf are comprised of the Sheikh, Syed and Pathan, whereas the Ajlafs have Qureshi, Saifi and Ansari biradaris. Maternal age was scored as above and below 45 years in each biradari. Significant effects of maternal age were seen on mortality of offspring, whereas populations did not show consistent differences, except when Ashrafs and Ajlafs were considered separately. The results show higher mortality and abortions for various groups. This may be due to various biological and socio-cultural factors, including hidden inbreeding in the remote past.
Modelling control measures to reduce the impact of pandemic influenza among schoolchildren
Authors: CHEN S.-C. , LIAO C.-M.
Published: September 2007

We coupled the Wells–Riley equation and the susceptible–exposed–infected–recovery (SEIR) model to quantify the impact of the combination of indoor air-based control measures of enhanced ventilation and respiratory masking in containing pandemic influenza within an elementary school. We integrated indoor environmental factors of a real elementary school and aetiological characteristics of influenza to estimate the age-specific risk of infection (P) and basic reproduction number (R0). We combined the enhanced ventilation rates of 0·5, 1, 1·5, and 2/h and respiratory masking with 60%, 70%, 80%, and 95% efficacies, respectively, to predict the reducing level ofR0. We also took into account the critical vaccination coverage rate among schoolchildren. Age-specificPandR0were estimated respectively to be 0·29 and 16·90; 0·56 and 16·11; 0·59 and 12·88; 0·64 and 16·09; and 0·07 and 2·80 for five age groups 4–6, 7–8, 9–10, 11–12, and 25–45 years, indicating pre-schoolchildren have the highest transmission potential. We conclude that our integrated approach, employing the mechanism of transmission of indoor respiratory infection, population-dynamic transmission model, and the impact of infectious control programmes, is a powerful tool for risk profiling prediction of pandemic influenza among schoolchildren.
Epidemiological features of Mediterranean spotted fever, murine typhus, and Q fever in Split-Dalmatia County (Croatia), 1982–2002
Authors: PUNDA-POLIĆ V. , LUKŠIĆ B. , ČAPKUN V.
Published: September 2007

We determined the epidemiological features of three zoonoses in hospitalized patients in southern Croatia. Patients were diagnosed by serological testing. Clinical and epidemiological data were also collected. Between 1982 and 2002, Mediterranean spotted fever (MSF) was diagnosed in 126 (incidence rate 1·27/100 000 per year), murine typhus (MT), in 57 (incidence rate 0·57/100 000 per year), and Q fever in 170 (incidence rate 1·7/100 000 per year) patients. MSF and Q fever were characterized by a marked seasonality. Incidences of Q fever and of MSF were higher for males than for females (P<0·0001 andP=0·0024, respectively). The most frequent of the three zoonoses in children was MSF. Q fever and MT cases were mostly seen in the 21–50 years age group. We found no statistically significant differences between season- and gender-specific incidence rates of MT. Whereas infections due to rickettsiae decreased, the incidence of Q fever increased over the last 12 years of the study.
Influence of the Amsterdam/St. Paul hot spot along the Southeast Indian Ridge between 77° and 88°E: Correlations of Sr, Nd, Pb, and He isotopic variations with ridge segmentation
Authors: Nicolaysen K. P. , Frey F. A. , Mahoney J. J. , Johnson K. T. M. , Graham D. W.
Published: September 2007

The submarine Amsterdam‐St. Paul (ASP) Plateau, bisected by the Southeast Indian Ridge (SEIR), is a bathymetric high rising ∼2 km above the surrounding seafloor that includes the islands of Amsterdam and St. Paul; this excess volcanism is attributed to a mantle hot spot. We obtained new Sr, Nd, and Pb (n = 37) and He isotopic (n = 10) ratios for basalt glasses from 11 SEIR segments on and adjacent to the plateau and from three seamounts on the plateau. The results show systematic spatial variations in these isotopic ratios that correlate with physical segmentation of the ridge. Specifically, lavas from the four ridge segments on the ASP Plateau have higher 208Pb/204Pb at a given 206Pb/204Pb than SEIR basalts distant from ASP Plateau. Surprisingly, lavas from the ridge segment 100 km north of the ASP Plateau are distinguished by the most radiogenic 206Pb/204Pb (up to 19.4) and highest 3He/4He ratios (up to 14.1 RA). These are characteristics of lavas erupted at Amsterdam and St Paul Islands. The isotopic data for SEIR basalts erupted on or adjacent to the ASP Plateau provide equivocal evidence for a mantle component derived from the distant Kerguelen hot spot. Overall, the Pb‐Nd‐Sr‐He isotope variations within this data set are explained well by three mantle end‐members: (1) depleted mantle having relatively low 206Pb/204Pb and 87Sr/86Sr and high 143Nd/144Nd, which has been variably mixed with (2) material having relatively high 208Pb/204Pb and 87Sr/86Sr and low 143Nd/144Nd, a signature commonly ascribed to detached or eroded metasomatized continental lithosphere, and (3) hot spot–related mantle having elevated 3He/4He and 206Pb/204Pb but intermediate 87Sr/86Sr and 143Nd/144Nd, similar to the common or C material observed in hot spots globally. These results suggest either that the ASP hot spot is isotopically heterogeneous or that the shallow mantle or lithosphere beneath the ASP Plateau contains more continentally derived material than the SEIR mantle ≥500 km away. Perhaps, like the 39°–41°E section of the Southwest Indian Ridge, beneath the ASP Plateau there are rafts of continental material stranded within a local “tectonic corridor,” possibly present since the opening of the Indian Ocean basin.
Internal tectonic structure of the Central American Wadati‐Benioff zone based on analysis of aftershock sequences
Authors: Špičák Aleš , Hanuš Václav , Vaněk Jiří , Běhounková Marie
Published: September 2007

Relocated Engdahl et al. (1998) global seismological data for 10 aftershock sequences were used to analyze the internal tectonic structure of the Central American subduction zone; the main shocks of several of these were the most destructive and often referenced earthquakes in the region (e.g., the 1970 Chiapas, 1983 Osa, 1992 Nicaragua, 1999 Quepos, 2001 El Salvador earthquakes). The spatial analysis of aftershock foci distribution was performed in a rotated Cartesian coordinate system (x, y, z) related to the Wadati‐Benioff zone, and not in a standard coordinate system (ϕ, λ, h are latitude, longitude, focal depth, respectively). Available fault plane solutions were also transformed into the plane approximating the Wadati‐Benioff zone. The spatial distribution of earthquakes in each aftershock sequence was modeled as either a plane fit using a least squares approximation or a volume fit with a minimum thickness rectangular box. The analysis points to a quasi‐planar distribution of earthquake foci in all aftershock sequences, manifesting the appurtenance of aftershocks to fracture zones. Geometrical parameters of fracture zones (strike, dip, and dimensions) hosting individual sequences were calculated and compared with the seafloor morphology of the Cocos Plate. The smooth character of the seafloor correlates with the aftershock fracture zones oriented parallel to the trench and commonly subparallel to the subducting slab, whereas subduction of the Cocos Ridge and seamounts around the Quepos Plateau coincides with steeply dipping fracture zones. Transformed focal mechanisms are almost exclusively (>90%) of normal character.
Complex seismic anisotropy at the border of a very low velocity province at the base of the Earth's mantle
Authors: Wang Yi , Wen Lianxing
Published: September 2007

We constrain the anisotropy associated with a very low velocity province (VLVP) at the base of the Earth's mantle using the SKS and SKKS waves sampling the region. Our selected high‐quality data sets consist of 415 SKS and 111 SKKS waveforms for 127 deep earthquakes recorded at distances between 90° and 150° by the seismic stations in three temporary broadband PASSCAL seismic arrays: the Kaapvaal seismic array (1997–1999), the Tanzania seismic array (1994–1995), and the Ethiopia/Kenya seismic array (1999–2001), as well as the permanent stations in the Global Seismographic Network. These seismic data provide good sampling coverage for some portion of the VLVP and its surrounding areas. Our results show, when the SKS or SKKS phases sample the regions away from the border of the VLVP (inside or outside the VLVP), the apparent splitting parameters inferred from the SKS phases are consistent with those inferred from the SKKS phases, and their variations strongly correlate with seismic stations but not with the exit points at the core‐mantle boundary of these seismic phases. However, when the SKS or SKKS phases sample near the border of the VLVP, the apparent splitting parameters inferred from the SKS phases and SKKS phases are different, and their variations no longer correlate with seismic stations. These features indicate that part of the shear wave splitting for the seismic data sampling the border of the VLVP has to originate from deep mantle, most likely near the border of the VLVP. We assume that the anisotropy in the shallow mantle beneath seismic stations has a horizontal hexagonal symmetry axis and infer the splitting parameters associated with the shallow anisotropy beneath the seismic stations using the SKS and SKKS waveforms for the seismic data sampling the regions away from the border of the VLVP. We then obtain the splitting parameters associated with the lowermost mantle anisotropy using the SKS and SKKS waveforms corrected for the inferred shallow anisotropy beneath seismic stations, assuming that the medium in the lowermost mantle also has a horizontal hexagonal symmetry axis. Our results reveal a complex anisotropy pattern near the border of the VLVP. Such a complex anisotropy pattern may be explained by lattice‐preferred orientation of anisotropic mantle aggregates aligned by a complex mantle flow near the VLVP margins. The complex flow pattern near the VLVP margins may indicate strong interactions between the VLVP, a compositional anomaly, and the surrounding normal mantle, and may provide an explanation to the concentration of some hot spots geographically near the borders of the VLVPs in the lowermost mantle.
January 2002 volcano‐tectonic eruption of Nyiragongo volcano, Democratic Republic of Congo
Authors: Tedesco D. , Vaselli O. , Papale P. , Carn S. A. , Voltaggio M. , Sawyer G. M. , Durieux J. , Kasereka M. , Tassi F.
Published: September 2007

In January 2002, Nyiragongo volcano erupted 14–34 × 106 m3 of lava from fractures on its southern flanks. The nearby city of Goma was inundated by two lava flows, which caused substantial socioeconomic disruption and forced the mass exodus of the population, leaving nearly 120,000 people homeless. Field observations showed marked differences between the lava erupted from the northern portion of the fracture system and that later erupted from the southern part. These observations are confirmed by new 238U and 232Th series radioactive disequilibria data, which show the presence of three different phases during the eruption. The lavas first erupted (T1) were probably supplied by a residual magma batch from the lava lake activity during 1994–1995. These lavas were followed by a fresh batch erupted from fissure vents as well as later (May–June 2002) from the central crater (T2). Both lava batches reached the surface via the volcano's central plumbing system, even though a separate flank reservoir may also have been involved in addition to the main reservoir. The final phase (T3) is related to an independent magmatic reservoir located much closer (or even beneath) the city of Goma. Data from the January 2002 eruption, and for similar activity in January 1977, suggest that the eruptive style of the volcano is likely to change in the future, trending toward more common occurrence of flank eruptions. If so, this would pose a significant escalation of volcanic hazards facing Goma and environs, thus requiring the implementation of different volcano‐monitoring strategies to better anticipate where and when future eruptions might take place.
Dynamical response to differential rates of temperature change over sloping topography: Lough Corrib, Ireland
Authors: Cannaby H. , White M. , Bowyer P.
Published: September 2007

An enclosed water body, subjected to a uniform surface heat flux, exhibits differential rates of temperature change between shallow peripheral waters and adjacent deeper waters. The result is the formation of horizontal temperature gradients in regions of sloping topography, referred to as topographic temperature gradients (TTGs). An integrated observational and numerical study has been undertaken, considering the impact of TTGs on the basin‐scale dynamics of Lough Corrib, Ireland. Temperature time series recorded during the winter of 2001 revealed sustained surface temperature gradients parallel to sloping boundaries. Cold, dense water formed in peripheral regions of the lake cascaded down slope under the influence of gravity, forming density plumes that extended over horizontal scales of kilometers. Plumes were typically 8–12 m thick and traveled down slope at speeds in the range 4–10 cm s−1. Down‐slope cascading of cool water was typically initiated when the daily mean surface heat flux fell below −55 W m−2, meaning cascading occurred almost persistently throughout the period of seasonal cooling (from early September until early January). While cascading plumes exhibited a diurnal periodicity, individual cascading events were linked to the passing of weather systems, persisting for between 5 hours and 3.6 days. The cascading of dense water formed an important mechanism for the transport of peripheral waters to depth, greatly increasing rates of lake overturning and preventing stagnation during cool, calm conditions. The offshore transport owing to cascading was balanced by a weaker and more diffuse onshore flow within the upper 5 m of the water column. Quasi‐geostrophic alongshore currents, evident in the modeled velocity field, formed a basin‐scale anticyclonic gyre during calm conditions.
A regional numerical ocean model of the circulation in the Bay of Biscay
Authors: Friocourt Y. , Levier B. , Speich S. , Blanke B. , Drijfhout S. S.
Published: September 2007

The seasonal circulation along the northern Iberian Peninsula and in the Bay of Biscay is investigated by means of a regional ocean model. In particular, the modeled velocities and tracers are compared to available observations and used to hypothesize what the circulation may look like in areas where the density of observations is scarcer. Despite a few biases in the thermohaline properties of some water masses, the model is able to represent the various water masses present in the region in an acceptable way. In particular, the density and depth ranges of most water masses are in good agreement with observed ranges. Similarly, the circulation schemes compare generally well with observations, both in annual mean as for the seasonal features. The model simulates a baroclinic slope current system that extends within the upper 2000 m and is subject to a strong seasonal variability. As a result, these slope currents are seen to reverse seasonally at all depths. A numerical Lagrangian analysis indicates that water masses cannot be transported continuously within the slope currents in or out of the Bay of Biscay because of the flow reversals associated with this seasonality. Instead, this analysis highlights the numerous connections with the slope current system and the interior, in agreement with Lagrangian drifter data.
Diurnal peroxy radical chemistry at a remote coastal site over the sea of Japan
Authors: Qi Bin , Kanaya Yugo , Takami Akinori , Hatakeyama Shiro , Kato Shungo , Sadanaga Yasuhiro , Tanimoto Hiroshi , Kajii Yoshizumi
Published: September 2007

The Rishiri Fall Experiment (RISFEX) was performed in September 2003 at a remote coastal site (45.07°N, 141.12°E, and 35 m asl) on Rishiri Island in the Sea of Japan. Peroxy radicals were measured from 15–21 September using a peroxy radical chemical amplifier (PERCA) instrument. Simultaneously measured were O3, NO, NO2, CO, nonmethane hydrocarbons (NMHCs), biogenic volatile organic compounds (BVOCs), carbonyl compounds, aromatics, volatile organoiodines, organobromines, black carbon, aerosols and photolysis frequencies of j(O1D) and j(NO2) as well as meteorological parameters. The data set covers the measurements under relative background conditions and polluted episodes over the period. The midday 30‐min averages of peroxy radicals ranged from 10 to 40 pptv with the highest observed on the event when the air masses were transported over the polluted continent in northern China before reaching the site. The significant radical signals were observed repeatedly in the early morning and late afternoon when j(O1D) was greatly reduced, resulting in the diurnal cycles of peroxy radicals much broader than those expected from the photolysis of O3 alone. A box model based on RACM (Regional Atmospheric Chemistry Mechanism) was used to calculate OH, HO2 and RO2 concentrations from measured stable species and parameters. The calculated peroxy radical concentrations agree well with measured ones during 0900–1530 Japan Standard Time (JST) (JST = UT + 9 hours) from 19 to 21 September. However, in the early morning and later afternoon when monoterpenes were the dominant VOC, the model overpredicts peroxy radicals by up to 85%. The including of uptake of radicals to aerosols into the model cannot account for the discrepancy. An underprediction by the model up to 45% was observed during noon hours on 18 September when isoprene concentration was high. It appears that unknown terpenes are present, which might produce extra radicals beyond the predicted by the model. The measured‐to‐modeled ratio of peroxy radical concentrations is near unity for [NO] < 120 pptv, but rises up to 15 for [NO] > 120 pptv, suggesting the presence of an unknown radical production process which is related with high NO concentration.
PlanetWRF: A general purpose, local to global numerical model for planetary atmospheric and climate dynamics
Authors: Richardson Mark I. , Toigo Anthony D. , Newman Claire E.
Published: September 2007

A new planetary atmospheric numerical model, “planetWRF,” has been developed by modifying the Weather Research and Forecasting (WRF) model. The model has generalized map projection, multiscale, and nesting capabilities, blurring the distinction between global and mesoscale models and enabling investigation of coupling between processes on all scales, including global. The model can also be run in one, two, or three dimensions. The conversion of the dynamical core for global application by altering the map projection grid and the boundary conditions as well as conversion of the physics parameterizations and constants for planetary application are described. Validation of the global dynamical core through use of standard forcing scenarios is presented. Example results from a series of simulations for Mars, Titan, and Venus are shown to demonstrate that the model performs well for a variety of planets and operating modes (microscale, mesoscale, and global scale).
Stealth quasi‐circular depressions (sQCDs) in the northern lowlands of Mars
Authors: Buczkowski Debra L.
Published: September 2007

While QCDs are quasi‐circular depressions revealed in the Mars Orbiter Laser Altimeter (MOLA) gridded data set, “stealth QCDs” (sQCDs) are those QCDs that have no obvious structural representation in visible images of Mars. It has been suggested that sQCDs are surface representations of buried impact craters, and on the basis of this assumption, size‐frequency distributions of all QCDs in the northern lowlands have been constructed to date the buried lowland floor. Expanding upon previous studies of stealth QCDs around the Utopia Basin, 446 sQCDs with diameters ranging from 7 to 115 km have been identified in the northern lowlands of Mars. The direct relationship of sQCD surface relief to diameter indicates that stealth QCDs form due to differential compaction of a cover material over buried impact craters. A comparison of sQCD location to the geologic map of the northern lowlands reveals that stealth QCDs are only located in geologic units predicted to be capable of differential compaction, consistent with models of their formation. The slope of the trend of the sQCDs surface relief versus diameter has a coefficient of determination (R2) approaching 1, when sQCDs are evaluated by geologic unit and by regions of inferred comparable cover thickness. Trend‐slope analysis also indicates that the lowland cover material is thickest in the Scandia region and the center of the Borealis and Utopia basins and thinnest in Isidis Planitia and north of Arabia Terra.
Primary productivity response to Heinrich events in the North Atlantic Ocean and Norwegian Sea
Authors: Nave S. , Labeyrie L. , Gherardi J. , Caillon N. , Cortijo E. , Kissel C. , Abrantes F.
Published: September 2007

The last glacial was punctuated by several massive ice sheet surges into the North Atlantic that impacted surface water hydrology especially where icebergs melted. However, the links between variations in surface water hydrology and surface water productivity during these Heinrich events (HEs) remain uncertain. To address this issue, diatoms and organic carbon were examined across Heinrich event 1 (HE 1) and Heinrich event 4 (HE 4) in seven sediment cores spanning 40°N to 63°N latitude. Our results show low diatom abundances during HEs, consistent with decreased surface water productivity. Diatom dilution by increased sediment flux was tested by normalizing diatom abundance to a constant 230Th flux. Although the particle rain rate was enhanced during HEs, this does not explain the sharp drop in diatoms. During HE 4, surface productivity decreased at all latitudes examined, probably because of strong, year‐round stratification. The same inferred changes occurred during HE 1 within the area of maximum iceberg melting. However, at northern latitudes (above 50°N) the summer insolation increase of the glacial termination drove increased surface productivity during the whole period, including HE 1. Marine organic carbon, taken as independent proxy for export production, supports the diatom data. Trends shown by the productivity proxies evolve generally in parallel with the hydrographic proxies, with an increase in productivity when sea surface temperature increases.
Global phosgene observations from the Atmospheric Chemistry Experiment (ACE) mission
Authors: Fu Dejian , Boone Chris D. , Bernath Peter F. , Walker Kaley A. , Nassar Ray , Manney Gloria L. , McLeod Sean D.
Published: September 2007

The first study of the global distribution of atmospheric phosgene (COCl2) has been performed using solar occultation measurements from the Atmospheric Chemistry Experiment (ACE) satellite mission. A total of 5614 measured profiles spanning the period February 2004 through May 2006 were used in the study. The phosgene concentrations display a zonally symmetric pattern with the maximum concentration located approximately over the equator at about 25 km in altitude and the concentration decreases towards the poles. A layer of enhanced concentration of phosgene spans the lower stratosphere over all latitudes, with volume mixing ratios of 20–60 pptv. The ACE observations show lower phosgene concentrations in the stratosphere than were obtained from previous observations in the 1980s and 1990s. This has been attributed to a significant decrease in its source species, particularly two major sources CH3CCl3 and CCl4, since the introduction of restrictions required by the Montreal Protocol and its amendments.