bluuebunny/crossref_metadata_2025 huggingface dataset:
Contextualizing injury severity from occupational accident reports using an optimized deep learning prediction model
Authors: Khairuddin Mohamed Zul Fadhli , Sankaranarayanan Suresh , Hasikin Khairunnisa , Abd Razak Nasrul Anuar , Omar Rosidah
Published: April 2024

Background

This study introduced a novel approach for predicting occupational injury severity by leveraging deep learning-based text classification techniques to analyze unstructured narratives. Unlike conventional methods that rely on structured data, our approach recognizes the richness of information within injury narrative descriptions with the aim of extracting valuable insights for improved occupational injury severity assessment.

Methods

Natural language processing (NLP) techniques were harnessed to preprocess the occupational injury narratives obtained from the US Occupational Safety and Health Administration (OSHA) from January 2015 to June 2023. The methodology involved meticulous preprocessing of textual narratives to standardize text and eliminate noise, followed by the innovative integration of Term Frequency-Inverse Document Frequency (TF-IDF) and Global Vector (GloVe) word embeddings for effective text representation. The proposed predictive model adopts a novel Bidirectional Long Short-Term Memory (Bi-LSTM) architecture and is further refined through model optimization, including random search hyperparameters and in-depth feature importance analysis. The optimized Bi-LSTM model has been compared and validated against other machine learning classifiers which are naïve Bayes, support vector machine, random forest, decision trees, and K-nearest neighbor.

Results

The proposed optimized Bi-LSTM models’ superior predictability, boasted an accuracy of 0.95 for hospitalization and 0.98 for amputation cases with faster model processing times. Interestingly, the feature importance analysis revealed predictive keywords related to the causal factors of occupational injuries thereby providing valuable insights to enhance model interpretability.

Conclusion

Our proposed optimized Bi-LSTM model offers safety and health practitioners an effective tool to empower workplace safety proactive measures, thereby contributing to business productivity and sustainability. This study lays the foundation for further exploration of predictive analytics in the occupational safety and health domain.
CNN-GMM approach to identifying data distribution shifts in forgeries caused by noise: a step towards resolving the deepfake problem
Authors: Alnafea Roaa Mohamed , Nissirat Liyth , Al-Samawi Aida
Published: April 2024

Recently, there have been notable advancements in video editing software. These advancements have allowed novices or those without access to advanced computer technology to generate videos that are visually indistinguishable to the human eye from real ones to the human observer. Therefore, the application of deepfake technology has the potential to expand the scope of identity theft, which poses a significant risk and a formidable challenge to global security. The development of an effective approach for detecting fake videos is necessary. Here, we introduce a novel methodology that employs a convolutional neural network (CNN) and Gaussian mixture model (GMM) to effectively differentiate between fake and real images or videos. The proposed methodology presents a novel CNN-GMM architecture in which the fully connected (FC) layer in the CNN is replaced with a customized Gaussian mixture model (GMM) fully connected layer. The GMM layer utilizes a weighted set of Gaussian probability density functions (PDFs) to represent the distribution of data frequencies in both real and fake images. This representation indicates there is a shift in the distribution of the manipulated images due to added noise. The CNN-GMM model demonstrates the ability to accurately identify variations resulting from different types of deepfakes within the probability distribution. It achieves a high level of classification accuracy, reaching up to 100% in training accuracy and up to 96% in validation accuracy. Notwithstanding the ratio of the genuine class to the counterfeit class being 16.6% to 83.4%, the CNN-GMM model exhibited high-performance metrics in terms of recall, accuracy, and F-score when classifying the least genuine class.
Citizen science initiatives document biodiversity baselines at an urban lake
Authors: Ahern Alyssah , Hughes Daniel F.
Published: April 2024

Changes to biodiversity from urbanization are occurring worldwide, and baseline data is vital to document the magnitude and direction of these alterations. We set out to document the biodiversity of an urban lake in Eastern Iowa that was devoid of baseline data prior to a renovation project that will convert the site into a major area for human recreation. Throughout the course of one year, we studied the biodiversity at Cedar Lake utilizing the citizen-science application iNaturalist coupled with semi-structured BioBlitz events, which we compared to previous opportunistic observations at the site. From a semi-structured approach to document biodiversity with citizen science, our analyses revealed more diverse community metrics over a shorter period compared to more than a decade of prior observations.
Rare Presentation of Metastatic Papillary Thyroid Carcinoma with Cribiform Type in Pelvic Bones
Authors: Alberto Del Corral-Vázquez Rodolfo , Ramírez Verónica Argüello
Published: April 2024

The papillary thyroid carcinoma is the most common endocrinologic neoplasm. Only the 10% of all patients have metastasis, however as high as 50% of all will have metastasis at the moment of the diagnosis. Lung and bone being the primary organs affected, only 5% are in other areas of the body. The Gold Standard for the diagnosis is the high-resolution ultrasound of the thyroid complementing with fine needle puncture-aspiration assessment, which help us in the decision making.
A Review on the Chemical Constituents, Anti-inflammatory and Anti-oxidant Agents from Combretum Genus
Authors: Ali Jude Ibeabuchi , Asogwa Felix Keneolisa , Ugwu Celestine Obiora , Okorie Hannah Ndidiamaka , Ujam Treasure Nonye , Obidiegwu Onyeka Chinwuba , Okoye Festus BC
Published: April 2024

Many diseases are treated using medicinal plants because they contain components that have therapeutic properties. The prevention and treatment of diseases linked to oxidative stress depend heavily on antioxidants. With over 20 genera and 600 species, the Combretaceae family is a vast group of plants that is distributed tropically throughout the world, with centers of diversity in Africa and Asia. In traditional medicine, certain species of Combretum are widely used as diuretics and to treat bleeding, diarrhea, infections, diabetes, malaria, and inflammation. This work is a review of Combretum species that have been assessed for their biological activity. It is imperative that more research be done on Combretum species in order to generate novel therapeutic options that could potentially enhance the well-being of individuals with a range of ailments.
Epidemiology of Antimicrobial Resistance and the Wash Project: Averting a Potential Public Health Crisis in Nigeria Using the United Kingdom as a Case Study
Authors: Ezugwu Nnenna Victoria , Gayle Alicia , Anyamene Chris
Published: April 2024

Aim: To assess the impact of WASH services in mitigating the proliferation of AMR in Nigeria, with the United Kingdom serving as a reference population.
Study Design: This is a review article.
Duration of Study: An extensive review was conducted in relevant databases, specifically focusing on research studies published in peer-reviewed journals in English. These studies were conducted in both the United Kingdom and Nigeria, with the primary objective of investigating the relationship between Water, Sanitation, and Hygiene practices and Antimicrobial Resistance. The search spanned from May 2015, coinciding with the adoption of the global action on antimicrobial resistance by the World Health Assembly, to July 2023. The literature search was completed on August 10, 2023.
Methodology: The search involved electronic databases such as EBSCO, PubMed, Science Direct, and CINAHL Complete. Additionally, relevant literature was searched on the websites of organizations such as the World Health Organization, Nigeria Centre for Disease Control and Prevention, and the Centre for Disease Control and Prevention, Public Health England. The quality of the papers was evaluated using CASP tools to determine their reproducibility, credibility, dependability, and confirmability. Out of the initial 705 articles that were drawn from the different databases, 12 studies were included in the literature review.
Results: The review of the various literature showed that WASH interventions in Nigeria are geared toward disease transmission/infection prevention and control and not the combatting of AMR while studies in the UK have shown positive advances in tackling AMR utilizing WASH services.
Conclusion: Promoting the development and provision of WASH infrastructure in diverse Nigerian settings is crucial for addressing antimicrobial resistance (AMR). This literature review serves as a call to action for stakeholders at the national, regional, and local levels in Nigeria, emphasizing the necessity of nationwide investment in WASH infrastructure, the development of policies that support the implementation of WASH in all the communities and villages, extensive health promotion campaigns to raise awareness about AMR, and community-level interventions to contain the spread of AMR in Nigeria.
Therapeutic Values of Pyridine Molecules from Natural Sources: A Comprehensive Review
Authors: Christi V.E. Ida , Chowdary J. Shashank , Kumar S. Saran , Jubilee R. , Victa N.I. Blessy , Nachiar G. Shanthini
Published: April 2024

Reason for the Study: Many commercial pharmacologically interesting medicinal plant species and their formulations are used in more communities and often in more countries around the world, for their multiple uses of Active compounds from the natural sources. It should be need to extensively explored to get their properties and their benefits. The costs of drugs for resistance of common infective diseases are increased especially bacterial infections and sexually transmitted diseases. The therapeutic approach of herbal medicines is an option for concerted search for new chemical entities for new drugs development. So searching of valuable medicinal plants with their longest track record for their use and their location and distribution is must and essential.

Aim: This study aims to provide an overview and documentation about pyridine alkaloids and their phytopharmacological activity related some medicinal plants.

Methodology: By using the key words, the literatures were collected from Science Direct, PubMed and Google Scholar search engines. This review will create a platform to harmonizing the traditional medicine practice in the country, create a synergy between herbal medicines and modern medicine and more harmonized integrated traditional medicine practices in future. It gives an insight into the strategic plan and route map for the development of new formulations and research platform for the practice and development of herbal medicines. The pharmaceutical industry has come to consider traditional medicine as a source for identification of bio-active agents that can be used in the preparation of semi synthetic medicine in different novel formulations.

Conclusion: This article focused some medicinal plants which contain different types and derivatives of pyridine alkaloids with their therapeutic applications. Further research needs to be done to make Novel pharmaceutical preparations with patent drugs and appropriate therapeutic documentation.
Determination of Radon Concentrations in Selected Soil Samples from the City of Mosul Using Nuclear Track Detector CR-39
Authors: Khudhur Omar I.
Published: April 2024

In this study, concentrations of radioactive radon gas were found in 24 soil samples for selected sites from Mosul (the center of Nineveh governorate) in northern Iraq, using the CR-39 nuclear track detector, to determine the extent of pollution in those sites and the extent of the danger of this gas to the health of individuals in these areas, where samples were collected from the areas under study and placed in irradiation chambers with reagents for 85 days to record the effects of alpha emitted from radon gas with optical microscope after the chemical etching process. The results showed that the highest concentration of radon gas at the study sites was at the Ibn Sina Hospital site (307.18 Bq/m3), and the lowest value was in the Qulayyat area, by an amount of (16.29 Bq/m3), and by an average of (99.85 Bq/m3), noting the recommended value of (200 Bq/m3) by (ICRP, 1993).
Progression of left ventricular enlargement in patients with hypertrophic cardiomyopathy: Incidence and prognostic value–K. Hina ef al.: Ventricular enlargement in HCM
Authors: Hina Kazuyoshi , Iwasaki Kohichiro , Nogami Kunio , Kita Toshimasa , Taniguchi Gyou , Kusachi Shozo , Moritani Hiroki , Tsuji Takao
Published: December 2008

A total of 51 patients with hypertrophic cardiomyopathy (HCM) were followed for at least 3 years (mean follow‐up period 6.5 years) by serial M‐mode and two‐dimensional echocardiography. An increase of the left ventricular diastolic dimension (LVDd) to ≥ 55 mm with a decrease in the left ventricular ejection fraction (LVEF) to < 55% was observed in eight (15.7%) patients (progressive disease group). In five of these eight patients, the LVDd was ≥ 60 mm and the LVEF was < 40%. Ventricular enlargement was closely related to mortality and death due to congestive heart failure occurred in three of these patients. No deaths occurred among the 37 patients without significant progression of ventricular enlargement (nonprogressive group). The annual changes of LVEF and LVDd in the progressive disease group were larger than in the nonprogressive group (LVEF – 0.18 ± 1.45 vs. – 2.46 ± 1.47 %/year; LVDd 0.22 ± 0.81 vs. 1.43 ± 0.77 mm/year). An increment in LVDs occurred earlier than the enlargement of the LVDd. Therefore, close attention to the LVDs seems to be important to detect early left ventricular morphological changes in HCM. In summary, this study indicates that HCM patients include a subgroup with symptoms resembling dilated cardiomyopathy, in whom the left ventricle enlarges with hypofunction and in whom there is high mortality due to congestive heart failure.
Regulation of focal adhesion formation and filopodia extension by the cellular prion protein (PrPC)
Authors: Schrock Yvonne , Solis Gonzalo P. , Stuermer Claudia A.O.
Published: December 2008

While the prion protein (PrP) is clearly involved in neuropathology, its physiological roles remain elusive. Here, we demonstrate PrP functions in cell–substrate interaction in Drosophila S2, N2a and HeLa cells. PrP promotes cell spreading and/or filopodia formation when overexpressed, and lamellipodia when downregulated. Moreover, PrP normally accumulates in focal adhesions (FAs), and its downregulation leads to reduced FA numbers, increased FA length, along with Src and focal adhesion kinase (FAK) activation. Furthermore, its overexpression elicits the formation of novel FA‐like structures, which require intact reggie/flotillin microdomains. Altogether, PrP modulates process formation and FA dynamics, possibly via signal transduction involving FAK and Src.
Cu,Zn‐superoxide dismutase is necessary for proper function of VDAC in Saccharomyces cerevisiae cells
Authors: Karachitos Andonis , Galganska Hanna , Wojtkowska Malgorzata , Budzinska Malgorzata , Stobienia Olgierd , Bartosz Grzegorz , Kmita Hanna
Published: December 2008

Available data suggest that a copper‐and zinc‐containing dismutase (CuZnSOD) plays a significant role in protecting eukaryotic cells against oxidative modifications which may contribute to cell aging. Here we demonstrated that depletion of CuZnSOD in Saccharomyces cerevisiae cells (Δ
sod1 cells) affected distinctly channel activity of VDAC (voltage dependent anion selective channel) and resulted in a moderate reduction in VDAC levels as well as in levels of protein crucial for VDAC import into mitochondria, namely Tob55/Sam50 and Tom40. The observed alterations may result in mitochondriopathy and subsequently in the shortening of the replicative life span observed for S. cerevisiae Δ
sod1 cells.
Continuous subsurface velocity measurement with coda wave interferometry
Authors: Wang Baoshan , Zhu Ping , Chen Yong , Niu Fenglin , Wang Bin
Published: December 2008

A 1‐month field experiment was conducted near Kunming in Yunnan Province, China, to continuously monitor subsurface velocity variations along different baselines. The experiment site is located 10 km west to the seismically very active Xiaojiang fault zone. An electric hammer was used as a source to generate highly repeatable seismic waves, which were recorded by 5 short‐period seismometers deployed at ∼10 m to 1.2 km away from the source. Velocity variation was estimated by using coda wave interferometry technique. The technique measures changes in differential time between the coda and the first arrival, which is in principal insensitive to timing errors. We obtained a fractional velocity perturbation (δv/v) of 10−3 to 10−2 with a precision of 10−4. The measured velocity variation is consistent among different components and stations and appears to well correlate with deep water level. The velocity variation is featured by a long‐term linear trend and well‐developed daily cycles. The latter is interpreted as the velocity response to the barometric pressure. A multivariate linear regression analysis of the data indicates that the velocity change exhibits a negative correlation with barometric pressure, with a stress sensitivity of 10−6/Pa at the experimental site.
High Resolution Imaging Science Experiment (HiRISE) observations of glacial and periglacial morphologies in the circum‐Argyre Planitia highlands, Mars
Authors: Banks Maria E. , McEwen Alfred S. , Kargel Jeffrey S. , Baker Victor R. , Strom Robert G. , Mellon Michael T. , Gulick Virginia C. , Keszthelyi Laszlo , Herkenhoff Kenneth E. , Pelletier Jon D. , Jaeger Windy L.
Published: December 2008

The landscape of the Argyre Planitia and adjoining Charitum and Nereidum Montes in the southern hemisphere of Mars has been heavily modified since formation of the Argyre impact basin. This study examines morphologies in the Argyre region revealed in images acquired by the High Resolution Imaging Science Experiment (HiRISE) camera and discusses the implications for glacial and periglacial processes. Distinctive features such as large grooves, semicircular embayments in high topography, and streamlined hills are interpreted as glacially eroded grooves, cirques, and whalebacks or roche moutonnée, respectively. Large boulders scattered across the floor of a valley may be ground moraine deposited by ice ablation. Glacial interpretations are supported by the association of these features with other landforms typical of glaciated landscapes such as broad valleys with parabolic cross sections and stepped longitudinal profiles, lobate debris aprons interpreted as remnant debris covered glaciers or rock glaciers, and possible hanging valleys. Aligned boulders observed on slopes may also indicate glacial processes such as fluting. Alternatively, boulders aligned on slopes and organized in clumps and polygonal patterns on flatter surfaces may indicate periglacial processes, perhaps postglaciation, that form patterned ground. At least portions of the Argyre region appear to have been modified by processes of ice accumulation, glacial flow, erosion, sediment deposition, ice stagnation and ablation, and perhaps subsequent periglacial processes. The type of bedrock erosion apparent in images suggests that glaciers were, at times, wet based. The number of superposed craters is consistent with geologically recent glacial activity, but may be due to subsequent modification.
Triggering and drainage mechanisms of the 2004 glacier‐dammed lake outburst in Gornergletscher, Switzerland
Authors: Sugiyama S. , Bauder A. , Huss M. , Riesen P. , Funk M.
Published: December 2008

To investigate the triggering and the drainage mechanisms of a glacier‐dammed lake outburst, we conducted high‐frequency measurements of the ice surface motion in the vicinity of Gornersee, an ice marginal lake on Gornergletscher, Switzerland. During the outburst event in July 2004, the ice surface within a distance of 400 m from the lakeshore moved vertically upward by up to 0.1 m. This vertical surface motion cannot be explained by vertical straining of ice which was measured in one of the boreholes; therefore, we suggest the separation of the glacier sole from the bed was caused by subglacially drained lake water. Our observation indicates that the lake water drained as a sheet‐like flow through the space created by the basal separation. The upward surface motion was greater in the region where the ice flotation level was exceeded by the lake level, implying that the ice barrier was breached when the lake water hydraulically connected to the bed and lifted up the glacier. In addition to the centimeter‐scale vertical ice motion, three survey stakes located within 100 m from the lake showed extraordinarily large vertical displacement of 0.5–3.0 m associated with abrupt changes in horizontal flow direction. A plausible interpretation is that the marginal ice wedge bent upward because of the buoyancy force generated by the drained water. Such bending is possible if subglacial and englacial fractures formed at about 200 m from the glacier margin and acted as a hinge. The newly formed and preexisting englacial fractures probably took the role of inducing englacial water drainage which preceded the outburst.
Identification of Saturn's magnetospheric regions and associated plasma processes: Synopsis of Cassini observations during orbit insertion
Authors: André N. , Blanc M. , Maurice S. , Schippers P. , Pallier E. , Gombosi T. I. , Hansen K. C. , Young D. T. , Crary F. J. , Bolton S. , Sittler E. C. , Smith H. T. , Johnson R. E. , Baragiola R. A. , Coates A. J. , Rymer A. M. , Dougherty M. K. , Achilleos N. , Arridge C. S. , Krimigis S. M. , Mitchell D. G. , Krupp N. , Hamilton D. C. , Dandouras I. , Gurnett D. A. , Kurth W. S. , Louarn P. , Srama R. , Kempf S. , Waite H. J. , Esposito L. W. , Clarke J. T.
Published: December 2008

Saturn's magnetosphere is currently studied from the microphysical to the global scale by the Cassini‐Huygens mission. During the first half of 2004, in the approach phase, remote sensing observations of Saturn's magnetosphere gave access to its auroral, radio, UV, energetic neutral atom, and dust emissions. Then, on 1 July 2004, Cassini Saturn orbit insertion provided us with the first in situ exploration of Saturn's magnetosphere since Voyager. To date, Saturn orbit insertion is the only Cassini orbit to have been described in common by all field and particle instruments. We use the comprehensive suite of magnetospheric and plasma science instruments to give a unified description of the large‐scale structure of the magnetosphere during this particular orbit, identifying the different regions and their boundaries. These regions consist of the Saturnian ring system (region 1, within 3 Saturn radii (RS)) and the cold plasma torus (region 2, within 5–6 RS) in the inner magnetosphere, a dynamic and extended plasma sheet (region 3), and an outer high‐latitude magnetosphere (region 4, beyond 12–14 RS). We compare these observations to those made at the time of the Voyager encounters. Then, we identify some of the dominant chemical characteristics and dynamical phenomena in each of these regions. The inner magnetosphere is characterized by the presence of the dominant plasma and neutral sources of the Saturnian system, giving birth to a very special magnetosphere dominated by water products. The extended plasma sheet, where the ring current resides, is a variable region with stretched magnetic field lines and contains a mixture of cold and hot plasma populations resulting from plasma transport processes. The outer high‐latitude magnetosphere is characterized by a quiet magnetic field and an absence of plasma. Saturn orbit insertion observations enabled us to capture a snapshot of the large‐scale structure of the Saturnian magnetosphere and of some of the main plasma processes operating in this complex environment. The analysis of the broad diversity of these interaction processes will be one of the main themes of magnetospheric and plasma science during the Cassini mission.
Pull‐apart basin formation and development in narrow transform zones with application to the Dead Sea Basin
Authors: Smit J. , Brun J.‐P. , Cloetingh S. , Ben‐Avraham Z.
Published: December 2008

Contrary to other examples, like Death Valley, California, and the Sea of Marmara, Turkey, the Dead Sea‐type pull‐apart basins form within a narrow transform corridor between strike‐slip faults that are less than 10 km apart, much smaller than the crustal thickness of 35 km. In this paper we investigate the role of fault zone width versus thickness and rheology on the mechanics of pull‐apart basins through a series of laboratory experiments. Results show that pull‐apart basins that develop above a small step over (i.e., smaller than the thickness of the brittle layer") are narrow and elongated parallel to the overall motion. This is enhanced by increased decoupling along a basal ductile layer. The experiment with the highest degree of mechanical decoupling shows a striking resemblance to the Dead Sea Basin (DSB). Comparison with modeling results suggests that the DSB's flat basin floor is bordered over its full length by strike‐slip faults that control the basin geometry and temporal and spatial basin migration. This is in strong contrast to Death Valley‐type pull‐apart basins that are highly oblique to the transform direction with transverse normal faults dominating over longitudinal strike‐slip faults. Results imply that lithosphere rheology and the ratio of basin width to crustal thickness are controlling factors in the mechanics of pull‐apart basin formation within transform corridors like the Dead Sea Fault.
Streamflow generation from snowmelt in semi‐arid, seasonally snow‐covered, forested catchments, Valles Caldera, New Mexico
Authors: Liu Fengjing , Bales Roger C. , Conklin Martha H. , Conrad Mark E.
Published: December 2008

Streamflow generation in the semiarid, seasonally snow‐covered, and forested mountain catchments of the Valles Caldera, New Mexico, was investigated using chemical tracers. Samples were collected from snow, subsurface flow from hillslopes, and streamflow at Redondo and La Jara Creeks from December 2004 to July 2005. A new modeling procedure was developed by combining diagnostic tools of mixing models and end‐member mixing analysis to evaluate the assumptions of mixing models. This procedure was successfully used to determine conservative chemical tracers, identify the number of end‐members that contribute to streamflow, and evaluate eligibility of end‐members. The results show that streamflow at Redondo Creek was generated from two end‐members: lateral subsurface flow (∼80%) and thermal meteoric water (∼20%). Streamflow at La Jara Creek was primarily from lateral subsurface flow alone. Overland flow of snowmelt was not a significant contributor to streamflow in either catchment. Lateral subsurface flow is an important process of streamflow generation in semiarid environments in the southwest United States and should play a critical role in regulating biogeochemical cycles.
Predicting export of dissolved organic carbon from forested catchments in glaciated landscapes with shallow soils
Authors: Creed I. F. , Beall F. D. , Clair T. A. , Dillon P. J. , Hesslein R. H.
Published: December 2008

This study presents a simple model of dissolved organic carbon (DOC) loading to surface waters that is applicable to headwater catchments in forested regions on glaciated landscapes. Average annual DOC export was highly variable among the 33 experimental catchments along an east‐west transect, ranging from 0.90 to 13.74 g C/m2/a. It was hypothesized that the proportion of wetlands within the catchments would explain the majority of variation in average annual DOC export. To test this hypothesis, digital terrain analysis was used to derive wetlands automatically under both open and closed forest canopies by identifying the probability of a grid cell being a depression and/or flat. Using a 10 m digital elevation model (DEM) derived from readily available sources, the proportion of wetlands explained 63% of the variance in average annual DOC export among the 33 experimental catchments. Inclusion of regional climatic indicators, including the number of growing degree days (with a base of 10°C) and the runoff coefficient, increased explanation of variance from 63% to 89%, once catchments with lakes (>5% of catchment area) adjacent to the catchment outlets were removed. This study shows that DOC export can be predicted accurately from headwater catchments in forested regions on glaciated landscapes using a simple model based on the proportion of wetlands and easily calculated climatic variables.
Petrogenesis of arc lavas from the Rucu Pichincha and Pan de Azucar volcanoes (Ecuadorian arc): Major, trace element, and boron isotope evidences from olivine‐hosted melt inclusions
Authors: Le Voyer Marion , Rose‐Koga Estelle F. , Laubier Muriel , Schiano Pierre
Published: December 2008

Primary melt inclusions in olivine phenocrysts (Fo74–89) of basic lavas from Pichincha and Pan de Azucar volcanoes (in the front and rear arcs of the Ecuadorian Andes, respectively) were analyzed by electron microprobe for major elements and by ion microprobe for trace element and boron isotope compositions. Although melt inclusions in the most magnesium‐rich olivines contain relatively primitive magmas, their compositions are not directly linked to those of the whole rocks through a differentiation scheme. They are characterized by nepheline‐normative compositions with low SiO2 contents (39.8–47.9 wt%) and unusually high CaO contents (up to 15.4 wt%), which cannot be derived from melting of a simple peridotitic mantle. We explain their formation by the presence of amphibole‐bearing olivine‐clinopyroxenites in the source of these melts. The trace elements patterns of the melt inclusions show the typical trace element features of arc magmas, such as enrichment in LILE and LREE, and negative anomalies in Nb and Ti. Across‐arc variations of mobile versus less mobile incompatible element ratios indicate a decreasing input of a mobile phase from the slab to the mantle wedge with the distance to the trench, along with a decrease in the degree of melting. Boron isotope compositions are highly variable within each volcano (δ11B from −9.5 ± 1.3‰ to +3.5 ± 1.4‰ for the Pichincha melt inclusions and from −17.9 ± 0.8‰ to −1.9 ± 1.4‰ for the Pan de Azucar melt inclusions) and suggest trapping of isotopically heterogeneous melts. Modeling of both dehydration and fusion of the slab indicates that the Pichincha melt inclusions were formed by melting a source enriched by the addition of 1% of a heterogeneous aqueous fluid derived from the dehydration of both the sediments and the altered oceanic crust (after 74 and 76% of B loss, respectively). The phase that metasomatizes the source of the Pan de Azucar melt inclusions can be either an input of 0.1% of a heterogeneous aqueous fluid or more likely 0.5–1% of a heterogeneous silicate melt.
Centennial‐scale Holocene North Atlantic surface temperatures from Mg/Ca ratios in Globigerina bulloides
Authors: Farmer Elizabeth J. , Chapman Mark R. , Andrews Julian E.
Published: December 2008

A high‐resolution record of Mg/Ca ratios from the planktonic foraminifer Globigerina bulloides has been produced for IMAGES core MD99–2251 from the subpolar North Atlantic. The record extends from the Younger Dryas‐Preboreal transition through the Holocene at ∼70 year resolution, with a more detailed section at ∼20 year resolution through the interval encompassing the major cooling episode 8200 years ago. Mg/Ca derived temperatures show significant variations through the Holocene, with surface temperatures ranging from ∼8 to 13°C. The onset of the Holocene is marked by an abrupt warming, with a further increase in early Holocene temperatures occurring prior to 9.5 ka. This is followed by a mid‐Holocene period of cooler and more stable conditions before temperatures show a stepped increase at ∼3.5 ka. The late Holocene period has the highest temperatures of the entire interglacial but also exhibits coolings of 2–3°C approximately every 500 years. Variations of this magnitude typify the high‐frequency component of temperature variability and do not seem to be restricted to the 8.2 ka event or the early Holocene, when stronger freshwater forcing associated with the decay of the ice sheets might be anticipated. However, episodes of enhanced drift ice input to North Atlantic are coincident with many of the Mg/Ca temperature minima over the last 6 ka. The long‐term warming trend and stepped increase in temperature at ∼3.5 ka are consistent with other planktonic foraminiferal records and appear to reflect regional‐scale changes in the atmospheric forcing of the North Atlantic Current during periods of rapid climate change. Alternatively, changes in ecology may contribute to the Holocene Mg/Ca record, either by species changing their depth habitat or by a shift in seasonal production patterns.
Illumination conditions at the lunar polar regions by KAGUYA(SELENE) laser altimeter
Authors: Noda H. , Araki H. , Goossens S. , Ishihara Y. , Matsumoto K. , Tazawa S. , Kawano N. , Sasaki S.
Published: December 2008

The sunlit conditions of the lunar polar regions were estimated by using a digital elevation model made by the laser altimeter data onboard the Japanese lunar orbiter KAGUYA (SELENE). The result shows that i) there are no peaks of eternal light in either north or south polar regions, ii) most continuously lit surfaces are 89% for north and 86% for south, iii) there are permanently shadowed regions. These information will be useful for the long‐durable landing experiments on the Moon and possibly for the human activity on the Moon in the near future.
Thermal anomalies indicate preferential flow along faults in unconsolidated sedimentary aquifers
Authors: Bense V. F. , Person M. A. , Chaudhary K. , You Y. , Cremer N. , Simon S.
Published: December 2008

Anomalously high (up to +8°C) and low (−2°C) groundwater temperatures, as compared to undisturbed geothermal profiles, have been observed in unconsolidated siliciclastic aquifers off‐set by normal‐faults in the Lower Rhine Embayment, Germany. High hydraulic head gradients, induced by pumping, over the same faults suggest that they form effective barriers to lateral groundwater flow. Numerical analysis of the geothermal data presented here shows that the observed thermal anomalies can be explained under the assumption that the faults form a sub‐vertical pathway that is connecting deep and shallow aquifers that are elsewhere separated by confining units. The hydraulic head and temperature observations taken together are consistent with the hypothesis that these faults behave as a conduit‐barrier systems. Such behavior would arise from clay‐smearing and drag of sand along the fault plane. Most current models of fault hydrology in unconsolidated sedimentary sequences assume faults to be effective barriers to fluid flow. Therefore our findings can have important consequences for the assessment of contaminant flow or hydrocarbon migration in sedimentary aquifer systems cut by faults.
Sea‐salt and dust aerosols in the ECMWF IFS model
Authors: Morcrette J.‐J. , Beljaars A. , Benedetti A. , Jones L. , Boucher O.
Published: December 2008

The ECMWF IFS model has recently been modified to include prognostic aerosols in its analysis and forecast modules. For the sea salt and dust components, comparisons of three versions of the model are presented: (i) a forecast only model started from conventional analysis with free‐running aerosols, (ii) a full analysis including aerosols, and (iii) as in (i) but with sea salt and dust sources revised to account for the 10‐m wind including gustiness and calibrated on the aerosol analysis results. It is shown that this new formulation of the sources of the main natural aerosols gives an improved agreement with AERONET surface observations where sea salt and dust aerosols are dominant. It also shows how the information brought by the aerosol analysis can be used to improve the representation of aerosols in numerical weather prediction and climate‐type general circulation models.
Simultaneous high P‐T measurements of ultrasonic compressional and shear wave velocities in Ichino‐megata mafic xenoliths: Their bearings on seismic velocity perturbations in lower crust of northeast Japan arc
Authors: Nishimoto Soshi , Ishikawa Masahiro , Arima Makoto , Yoshida Takeyoshi , Nakajima Junichi
Published: December 2008

Simultaneous measurements of ultrasonic compressional (Vp) and shear wave velocities (Vs) were conducted under pressures and temperatures representative of the lower crust on five mafic xenoliths derived from the northeast Japan arc crust. For comparison with the observed seismic heterogeneity of the lower crust of the northeast Japan arc, the velocity deviations (dVp and dVs) of the xenoliths were calculated using the average reference Vp (6.61 ± 0.1 km/s) and Vs (3.76 ± 0.1 km/s). The dVp and dVs values of the xenoliths at 700°C and 0.8 GPa are 0.8% and −1.2% for hornblende gabbro, 4.8% and 4.0% for hornblende‐pyroxene gabbro, 0.9% and −1.5% for amphibolite, 2.5% and 1.7% for pyroxene amphibolite, and 0.9% and −5.6% for hornblendite, respectively. We compared the velocity perturbations in the lower crust determined by seismic tomography with dVp and dVs of the xenoliths using “Vp−Vs−Vp/Vs deviation diagrams.” On the basis of our measurements, we suggest that (1) the seismically high‐Vp and Vs regions beneath the Tobishima Basin consist of hornblende‐pyroxene gabbro, (2) hornblende gabbro is a predominant rock type beneath the Dewa Hills and Ou Backbone Range, (3) the low‐velocity anomalies beneath the active volcano areas may be caused by the existence of partial melts of hornblende gabbro, and (4) the low‐Vp and high‐Vs regions beneath the Kitakami Mountains consist of quartz‐plagioclase‐bearing rocks. Our data demonstrate that the seismic heterogeneity in the lower crust of the northeast Japan arc reflects variations in rock composition and temperature that are related to the regional geological history.
How are saucer‐shaped sills emplaced? Constraints from the Golden Valley Sill, South Africa
Authors: Polteau S. , Ferré E. C. , Planke S. , Neumann E.‐R. , Chevallier L.
Published: December 2008

Magmatic sill intrusions develop saucer‐like geometries in layered sedimentary basins intruded by large volumes of magma. Saucer‐shaped sill emplacement models are based on the analysis of the intrusion geometry and their spatial relationships with potential feeders, not on magma flow pattern. The Karoo Basin of South Africa hosts hundreds of saucer‐shaped sills. Among these, the Golden Valley Sill is well exposed and displays connections with adjacent and nested saucers. A combination of detailed field observations and anisotropy of magnetic susceptibility measurements (AMS) were used to identify strain markers that can be interpreted in terms of magma flow directions. A total of 113 localities (six specimens per site), mostly including pairs of opposite sill margins, were sampled for anisotropy of magnetic susceptibility analyses. The magnetic properties were determined by measuring hysteresis loops and K‐T curves. The majority of the localities display well‐defined magnetic foliations that consistently dip outward from the center of the Golden Valley Sill. This orientation of the magnetic foliation most likely represents inflation/deflation cycles of the intruding sill that interacts with nonstatic enclosing walls. In addition, magma channels and ropy flow structures were identified and display an imbrication of the magnetic foliation indicating an outward magma flow direction. The observed magma flow geometries derived from macroscopic flow indicators and the AMS data correlate well and constrain an emplacement model for the Golden Valley Sill Complex. Our emplacement model integrates our observations with dynamic emplacement processes characterized by inflation and deflation cycles.
Correlation between crustal high conductivity zones and seismic activity and the role of carbon during shear deformation
Authors: Glover Paul W. J. , Ádám A.
Published: December 2008

The electrical conductivity of the lower crust is anomalously high in many locations around the world. Well‐interconnected grain boundary carbon not only has the potential for increasing the electrical conductivity of the rock but also would be expected to reduce its shear strength. We report a new analysis of field observations and new laboratory measurements consistent with deep carbon‐bearing rocks causing observed high conductivities and crustal weaknesses associated with increased seismicity. The field data indicate a correlation between the depths to a zone of high electrical conductivity observed in Transdanubia in Hungary, earthquake focal depths, and zones of high seismic attenuation. The laboratory triaxial deformation experiments show that progressive shearing of a fracture in carbon‐bearing rock can result in a weaker more electrically conductive fracture. These results provide strong evidence for the role of carbon at depth in both electrical conduction and seismotectonics, explaining the correlation between mid‐crustal high reflectivities and high conductivities observed at many locations worldwide.
Decadal variability of the Subtropical Front of the western North Pacific in an eddy‐resolving ocean general circulation model
Authors: Yamanaka Goro , Ishizaki Hiroshi , Hirabara Mikitoshi , Ishikawa Ichiro
Published: December 2008

We examined decadal variability of the Subtropical Front (STF) of the western North Pacific by using a North Pacific ocean general circulation model (OGCM), comparing the results of three simulations with different horizontal resolutions. In the long‐term mean fields, the eddy‐resolving model (10 km) was able to simulate the distributions of the STF and the associated Subtropical Countercurrent (STCC) between 20°N and 30°N better than either the non‐eddy‐resolving model (100 km) or the eddy‐permitting model (20 km) because it simulated the Kuroshio recirculation gyre more realistically. The simulated STF intensity exhibited significant decadal‐scale variations: it was stronger in the late 1970s and weaker in the early 1990s. During these two periods, the simulated mode waters showed corresponding differences in their potential vorticity minima density and paths. We also investigated the relationship between the decadal‐scale STF variability and atmospheric forcing. The results suggest that the decadal‐scale STF variability can be largely explained by changes in the mode waters formed in the western North Pacific and advected to north of the STF by the subtropical gyre in response to a change in surface westerly winds that occurred in the mid‐1970s.
Scale effect on statistics of the macrophysical properties of trade wind cumuli over the tropical western Atlantic during RICO
Authors: Dey Sagnik , Di Girolamo Larry , Zhao Guangyu
Published: December 2008

This study investigates the effect of observational domain size and pixel resolution on the statistics of macrophysical properties of trade wind cumulus clouds over the tropical western Atlantic. In order to better facilitate comparison with model simulations, the results are presented as an extension of earlier work by Zhao and Di Girolamo (2007), who have analyzed 152 Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) scenes collected between September and December 2004 to generate comprehensive statistics of cumulus clouds at the original 60 km × 60 km domain and 15 m pixel resolution of the data. The statistics change with domain size because as the domain size becomes smaller, (1) the probability of chopping clouds by the domain boundaries into smaller clouds increases, and (2) the probability of having cloudier and clearer domains increases. In addition, degrading pixel resolution results in (1) an amalgamation of smaller clouds into larger clouds, and (2) an increase in the frequency of partially filled cloudy pixels. The mean cloud fraction in our ASTER data set increases more than fourfold, with the total number of clouds reducing 26‐fold, when pixel resolution degrades from 15 m to ∼1 km. The cloud fraction frequency distribution becomes wider with a shift of the peak toward higher values at coarser resolution. However, at smaller domain sizes, the shift of the peak toward larger values due to pixel effects is overcompensated by the increase in frequency of smaller cloud fractions. The change in cloud size distribution is significant at domains smaller than 10 km × 10 km. An increase in the cloud size at coarser resolution shifts the peak of the size distribution toward larger values. At 15 m resolution, 98% of clouds are distributed at distances less than 300 m, with a peak in the nearest‐neighbor distance at less than 50 m at all domain sizes. The peak of the nearest‐neighbor distribution becomes wider and shifts to larger distances at coarser resolution. These results clearly indicate the importance of considering scale effect when comparing cloud resolving model simulations of trade wind cumuli with observations.
Antarctic isotopic thermometer during a CO2 forced warming event
Authors: Sime Louise C. , Tindall Julia C. , Wolff Eric W. , Connolley William M. , Valdes Paul J.
Published: December 2008

Results from an isotope‐enabled general circulation model are presented in order to determine the isotopic signal of a warmer climate on Antarctica. The warming is forced using CO2 forecasts for the next century. For unforced interannual climate variability the temporal gradient and correlation between stable water isotopes and surface temperature is small. The relationship is much stronger for the CO2 forced event. There is little regional coherence between temporal gradients for the forced and unforced climates, implying that correlations between stable water isotopes and temperature from instrumental records of a couple of decades cannot be applied to larger warming events. Additionally, there are strong discrepancies between the forced warming temporal gradients and present‐day spatial gradients of isotopes against temperature. We show that it is difficult to obtain a local spatial gradient since it is systematically affected by the geographical size of the spatial sample. For the forced warming, the temporal gradient derived for the warming event over Dome C is less than half the value generally applied. We determine, through means of a new frequency decomposition, that a large portion of this decrease from the expected value is due to changes in the seasonal precipitation temperature covariance. This low isotopic sensitivity to a CO2 driven warming implies that current and future warming trends may have rather small isotopic signals in Antarctica.