bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the Illinois Soil Nitrogen Test for Predicting Corn Nitrogen Needs
Authors: Osterhaus Jeffrey T. , Bundy Larry G. , Andraski Todd W.
Published: January 2008

Development of a diagnostic test to estimate soil N supplying capability is a continuing research need. The Illinois Soil Nitrogen Test (ISNT) has been proposed as a method for adjusting corn (Zea mays L.) N recommendations to account for soil organic N contributions by measuring hydrolyzable amino sugar‐N and NH4–N. The ISNT was evaluated as a tool for predicting corn N response in Wisconsin by comparing ISNT values and corn N response data from 80 experiments conducted between 1984 and 2004 with a range of crop rotations, management histories, and soils. Relationships between various hydrolyzable soil N fractions (including amino sugar‐N) and corn N response data were also evaluated using a subset (13 sites) of the 80 N response experiments. The subset was selected to obtain a wide range of anticipated soil N availability. Results showed that ISNT values were not related to observed economic optimum N rates in the corn N response experiments and that the ISNT had no ability to separate N‐responsive from unresponsive sites. Illinois Soil Nitrogen Test values were well correlated (R2 = 0.88) with the soil organic matter content of the experimental sites, suggesting that the ISNT is measuring a constant fraction of the soil organic N rather than the readily mineralizable N component. Soil organic N fractions measured in 13 experiments were not related to corn N response although these experiments included cropping systems ranging from first‐year corn following alfalfa (Medicago sativa L.) to continuous corn. Results from this work indicate that the ISNT and the soil organic N fractions studied are not reliable predictors of corn N response.
Mineralogy and Magnetic Properties of Basaltic Substrate Soils: Kaho'olawe and Big Island, Hawaii
Authors: Van Dam Remke L. , Harrison J. Bruce J. , Hirschfeld Deidre A. , Meglich Todd M. , Li Yaoguo , North Ryan E.
Published: January 2008

Magnetic behavior of soils can seriously hamper the performance of geophysical sensors. Currently, we have little understanding of the types of minerals responsible for the magnetic behavior, as well as their distribution in space and evolution through time. This study investigated the magnetic characteristics and mineralogy of Fe‐rich soils developed on basaltic substrate in Hawaii. We measured the spatial distribution of magnetic susceptibility (χlf) and frequency dependence (χfd%) across three test areas in a well‐developed eroded soil on Kaho'olawe and in two young soils on the Big Island of Hawaii. X‐ray diffraction spectroscopy, x‐ray fluorescence spectroscopy (XRF), chemical dissolution, thermal analysis, and temperature‐dependent magnetic studies were used to characterize soil development and mineralogy for samples from soil pits on Kaho'olawe, surface samples from all three test areas, and unweathered basalt from the Big Island of Hawaii. The measurements show a general increase in magnetic properties with increasing soil development. The XRF Fe data ranged from 13% for fresh basalt and young soils on the Big Island to 58% for material from the B horizon of Kaho'olawe soils. Dithionite‐extractable and oxalate‐extractable Fe percentages increase with soil development and correlate with χlfand χfd%, respectively. Results from the temperature‐dependent susceptibility measurements show that the high soil magnetic properties observed in geophysical surveys in Kaho'olawe are entirely due to neoformed minerals. The results of our studies have implications for the existing soil survey of Kaho'olawe and help identify methods to characterize magnetic minerals in tropical soils.
Modeling Tillage‐Induced Redistribution of Soil Mass and Its Constituents within Different Landscapes
Authors: Li Sheng , Lobb David A. , Lindstrom Michael J. , Papiernik Sharon K. , Farenhorst Annemieke
Published: January 2008

Tillage is a driving force of soil movement in cultivated fields. Soil constituents, together with the mass of soil, are redistributed across landscapes by tillage. The pattern of tillage‐induced soil constituent redistribution is determined by the pattern of tillage erosion (tillage‐induced soil mass loss or gain) and the dispersivity of translocation. In this study, we used a convoluting procedure and developed a Tillage Translocation Model (TillTM) to simulate the tillage translocation process and to demonstrate tillage‐induced soil mass and soil organic carbon (OC) (as an example of soil constituents) redistributions across four hypothetical landscapes subjected to different tillage patterns (directions) and over different lengths of tillage period. We determined that the local tillage‐erosion rate is mainly dependent on topography and that the effects of tillage pattern and the length of tillage period are relatively minor. The redistribution of OC content in the till layer is mainly determined by the number, location, and size of soil loss positions in the landscape, as well as the soil loss rates at these positions. Net loss of OC content occurs in the till layer and this loss increases with time. In contrast, an increase of OC content in the sublayer occurs at soil accumulation positions. The model was validated against field data collected at a site near Cyrus, MN. The patterns of OC and inorganic C redistribution can be adequately estimated by TillTM. There are discrepancies, however, between the model‐estimated values and the field measurements due to the limitations and uncertainties associated with the model. The results clearly showed that tillage translocation causes the vertical redistribution of soil constituents across the landscape, which implies that tillage translocation is one of the driving forces behind the spatial variability of soil properties and properties that impact biophysical processes.
Comparison of Solid‐State Carbon‐13 Nuclear Magnetic Resonance and Organic Matter Biomarkers for Assessing Soil Organic Matter Degradation
Authors: Simpson Myrna J. , Otto Angelika , Feng Xiaojuan
Published: January 2008

Soil organic matter (SOM) is a heterogeneous mixture of compounds that are derived from a number of sources. Therefore, trying to assess the stage of SOM alteration is challenging. Recently, our research has proposed a number of degradation parameters based on the measurement of SOM biomarkers. These biomarkers, which can be attributed to a specific organism source and the stage of alteration (oxidation) of a compound can provide information regarding the stage and rate of SOM degradation. The previously developed biomarker ratios for assessing SOM degradation have not been tested with degradation parameters derived from other molecular methods. This study investigates the use of solid‐state 13C nuclear magnetic resonance (NMR) and organic matter biomarker methods for the assessment of SOM degradation in four soils from Western Canada. Total solvent extraction was used to isolate free lipids, base hydrolysis was used to extract bound lipids, and copper (II) oxide (CuO) oxidation was used to liberate lignin monomers and dimers from the soil. The presence of plant sterols and their oxidative degradation products facilitated the analysis of SOM alteration. Cutin and suberin degradation parameters were applied to study the relative amounts of suberin versus cutin inputs into soil as well as the stage of cutin and suberin degradation. The extent of oxidation for lignin‐derived compounds was also tabulated. The trends observed by solid‐state 13C NMR (alkyl/O‐alkyl ratios) were consistent with those found with the biomarker techniques, however, it should be noted that the biomarker methods provide detailed information on specific compounds whereas solid‐state 13C NMR only provides information on the “bulk” structure of SOM. Because only a small portion of SOM components are amenable to analysis by biomarker methods, it is advantageous to use these methods in tandem with solid‐state 13C NMR spectroscopy and other molecular techniques when investigating SOM sources and biogeochemistry.
Evidence for Different Reaction Pathways for Liquid and Granular Micronutrients in a Calcareous Soil
Authors: Hettiarachchi Ganga M. , McLaughlin Mike J. , Scheckel Kirk G. , Chittleborough David J. , Newville Mathew , Sutton Steve , Lombi Enzo
Published: January 2008

The benefits of Mn and Zn fluid fertilizers over conventional granular products in calcareous sandy loam soils have been agronomically demonstrated. We hypothesized that the differences in the effectiveness between granular and fluid Mn and Zn fertilizers is due to different Mn and Zn reaction processes in and around fertilizer granules and fluid fertilizer bands. We used a combination of several synchrotron‐based x‐ray techniques, namely, spatially resolved micro‐x‐ray fluorescence (μ‐XRF), micro‐x‐ray absorption near edge structure spectroscopy (μ‐XANES), and bulk‐XANES and ‐extended x‐ray absorption fine structure (EXAFS) spectroscopy, along with several laboratory‐based x‐ray techniques to speciate different fertilizer‐derived Mn and Zn species in highly calcareous soils to understand the chemistry underlying the observed differential behavior of fluid and granular micronutrient forms. Micro‐XRF mapping of soil–fertilizer reactions zones indicated that the mobility of Mn and Zn from liquid fertilizer was greater than that observed for equivalent granular sources of these micronutrients in soil. After application of these micronutrient fertilizers to soil, Mn and Zn from liquid fertilizers were found to remain in comparatively more soluble solid forms, such as hydrated Mn phosphate‐like, Mn calcite‐like, adsorbed Zn‐like, and Zn silicate‐like phases, whereas Mn and Zn from equivalent granular sources tended to transform into comparatively less soluble solid forms such as Mn oxide‐like, Mn carbonate‐like, and Zn phosphate‐like phases.
Teaching Veterinary Radiography by E-Learning versus Structured Tutorial: A Randomized, Single-Blinded Controlled Trial
Authors: Vandeweerd Jean-Michel E.F. , Davies John C. , Pinchbeck Gina L. , Cotton Jo C.
Published: January 2008

Case-based e-learning may allow effective teaching of veterinary radiology in the field of equine orthopedics. The objective of this study was to investigate the effectiveness of a new case-based e-learning tool, compared with a standard structured tutorial, in altering students’ knowledge and skills about interpretation of radiographs of the digit in the horse. It was also designed to assess students’ attitudes toward the two educational interventions. A randomized, single-blinded, controlled trial of 96 fourth-year undergraduate veterinary students, involving an educational intervention of either structured tutorial or case-based e-learning, was performed. A multiple-choice examination based on six learning outcomes was carried out in each group after the session, followed by an evaluation of students’ attitudes toward their session on a seven-point scale. Text blanks were available to students to allow them to comment on the educational interventions and on their learning outcomes. Students also rated, on a Likert scale from 1 to 7, their performance for each specific learning outcome and their general ability to use a systematic approach in interpreting radiographs. Data were analyzed using the Mann-Whitney test, the t-test, and the equivalence test. There was no significant difference in student achievement on course tests. The results of the survey suggest positive student attitudes toward the e-learning tool and illustrate the difference between objective ratings and subjective assessments by students in testing a new educational intervention.
The Case Correlation Assignment: Connecting Antemortem and Postmortem Data in the Senior Year at Iowa State University
Authors: Fales-Williams Amanda , Danielson Jared , Myers Ronald , Sorden Steven , Bender Holly
Published: January 2008

Instructors of the senior necropsy rotation at Iowa State University experienced difficulty ensuring similarity of case exposure and workload during the year. This was problematic during times of low caseload, as, without necropsy cases, there was no uniform method for training or assessing students. A new assignment, the Case Correlation Assignment (CCA), was created in order to improve the educational rigor and consistency of the rotation, increase utilization of necropsy cases as teaching material, and provide students more opportunities to correlate clinical pathology data with lesions. The CCA provides an opportunity for senior students to present and explain the antemortem and postmortem findings from an ISU-VTH patient in case report format. This illustrated report is submitted via WebCT. Students receive feedback on WebCT through a scoring rubric and written comments from the instructor. Since 2002, approximately 420 students have completed this assignment. The average score on the assignment over the four-year period is 94.7%. Despite complaints about the hard work required, students generally report that writing the CCA is a valuable learning experience. The CCA allows for greater utilization of necropsy cases and the incorporation of clinical pathology into necropsy cases. Currently, the CCA is used in a peer-assessment assignment in the junior pathology course and has been incorporated into case-based teaching courses. The CCA has been revised and expanded over the past four years in response to student feedback and to the discovery of new ways to utilize the completed assignments as teaching material.
Distance Education But Beyond: “meLearning”—What If the Impossible Isn't?
Authors: Hodgins Wayne
Published: January 2008

It's not the physical distance between teachers and learners that is the problem but the gap between what all of us as learners need and what those who supply the education, training, and learning have to offer. Mass-produced education for the masses will give way to massively customized learning with contributions from all. While the scope of such an endeavor appears staggering, the dream of adaptive, personalized “meLearning” for every person every day, and thus the brightest future ever imagined, lies immediately in front of us and within our grasp.

The vision for a future world state where every person experiences personalized learning every day is clear, but it has arrived prematurely, is inequitably distributed, and remains unseen by most. Moreover, and as has been common in the history of conditions preceding such mass revolutions, the existing organizations and institution stand in stark contrast to this vision and, in many ways, oppose it. All quite predictable and understandable. However, the status quo is no longer an option. The distance between the supply side of the equation (solutions offered) and the demand side (demands and needs) is disproportionately large. Change is inevitable, and is increasingly demanded by all involved. If you have not done so already, it is time to start imagining what our world would be like if we increased the effectiveness of learning for everyone, all the time, by customizing the learning to fit each individual person and situation. Imagine if the impossible isn't! Many others already have.

This future is ours for the choosing if we can muster the courage to ignite the transformation from vision to reality by simply imagining that this bright future is now possible and beginning to shape its design and implementation.
Registration of ‘Guymon’ Wheat
Authors: Carver B. F. , Hunger R. M. , Edwards J. T. , Rayas-Duarte P. , Klatt A. R. , Porter D. R. , Seabourn B. W. , Bai G.-H. , Dowell F. E. , Yan L.-L. , Martin B. C.
Published: January 2008

‘Guymon’ (Reg. No. CV‐1018, PI 643133) is a hard white (HW) winter wheat (Triticum aestivum L.) cultivar developed and released cooperatively by the Oklahoma Agric. Exp. Stn. (AES) and the USDA‐ARS in 2005. It is recommended for areas of the southern High Plains centered by the city serving as its namesake, Guymon, OK.
Registration of Common Bacterial Blight, Rust and Bean Common Mosaic Resistant Great Northern Common Bean Germplasm Line ABC‐Weihing
Authors: Mutlu N. , Urrea C. A. , Miklas P. N. , Pastor-Corrales M. A. , Steadman J. R. , Lindgren D. T. , Reiser J. , Vidaver A. K. , Coyne D. P.
Published: January 2008

Great northern common bean (Phaseolus vulgaris L.) germplasm line ABC‐Weihing (Reg. No. GP‐246, PI 647964) was developed by the University of Nebraska Agricultural Research Division in cooperation with USDA‐ARS and released in 2006. This line, tested as NE1‐05‐4, was bred specifically for enhanced resistance to common bacterial blight (CBB), a major seed borne disease of common bean caused by the bacterium Xanthomonas campestris pv. phaseoli (Smith) Dye (Xcp). ABC‐Weihing is a great northern BC5F3:6 line obtained from five backcrosses (‘Weihing’*5//‘Chase’/XAN 159). The first cross was made in spring 1997. Only BCnF1 plants resistant to Xcp isolates Dominican Republic DR‐7 and Nebraska SC4A, as determined by multiple needle leaf inoculation tests in the greenhouse, were used for successive backcrossing. In addition to phenotypic selection for CBB resistance, marker‐assisted selection for the resistant QTL‐linked marker SU91 was conducted in the BC1F1, BC2F1, and ABC‐Weihing. When inoculated with Nebraska Xcp strains in the field, ABC‐Weihing exhibited resistance in both 2005 and 2006. ABC‐Weihing has Ur‐3 and Ur‐6 genes for resistance to common bean rust and carries the single dominant hypersensitive I gene that provides resistance to all non‐necrotic strains of the Bean common mosaic virus (BCMV). ABC‐Weihing has bright white seed, blooms 45 d after planting, and is a midseason bean maturing 92 d after planting.
Registration of ‘UI Darwin’ Wheat
Authors: Souza E. J. , Guttieri M. J. , O'Brien K. M. , Zemetra R. S.
Published: January 2008

‘UI Darwin’ (Reg. No. CV‐1022, PI 639953) is a hard white winter wheat (Triticum aestivum L.) developed by the Idaho Agricultural Experiment Station and released in February 2006. UI Darwin (pedigree IDO445/‘Manning’) was tested under the experimental numbers A93151W‐85 and IDO604. It is a tall semidwarf wheat released for crop‐fallow rotations of the Intermountain West, where few hard white wheat cultivars are available. UI Darwin has improved resistance to stripe rust (Puccinia striiformis Westend.) relative to ‘Bonneville’ hard red winter wheat with resistance to dwarf bunt (Tilletia controversa Kühn in Rabenh) at similar levels to Bonneville. In 16 rainfed yield trials grown in Idaho from 2001 to 2005, UI Darwin had an average grain yield of 3200 kg ha‐1, similar to Bonneville (3050 kg ha‐1) and ‘Weston’ (3190 kg ha‐1) but less than ‘Gary’ (3560 kg ha‐1. UI Darwin has improved bread baking quality compared with current hard white winter wheat cultivars and has excellent color in akaline noodle products. UI Darwin had an average pup‐loaf volume of 1075 mL, similar to hard red winter wheat cultivars Bonneville (1044 mL) and Weston (1064 mL) but greater than the hard white wheat cultivar Gary (963 mL).
Loss of presenilin function causes Alzheimer's disease‐like neurodegeneration in the mouse
Authors: Chen Qian , Nakajima Akira , Choi Se Hoon , Xiong Xiaoli , Tang Ya‐Ping
Published: January 2008

Accumulating evidence has indicated that gain‐of‐function in β‐amyloid production may be not the necessary mechanism for mutant presenilin‐1 (PS1) or PS2 to cause familial Alzheimer's disease (AD). In the present article, we show that conditional knockout of PS1 from the adult stage in the forebrain of mice with the PS2 null mutation triggers robust AD‐like neurodegeneration including brain shrinkage, cortical and hippocampal atrophy,ventricular enlargement, severe neuronal loss, gliosis, tau hyperphosphorylation, neurofillament tangle‐like structures, and intracellular filaments. Learning and memory functions in these mice are almost completely lost. Notably, there is no β‐amyloid deposition, indicating that presenilin dysfunction can directly cause neurodegeneration without the involvement of β‐amyloid. Furthermore, neurodegeneration occurs in a progressive manner following aging, suggesting that an accumulating effect of presenilin dysfunction over time might be a pathogenic mechanism for the involvement of mutant PS1/PS2 in causing AD. These results validate a mouse model characterized by the presence of many features of AD pathology. Furthermore, the demonstration of AD‐like neurodegeneration in the absence of β‐amyloid deposition challenges the long‐standing β‐amyloid cascade hypothesis and encourages an open debate on the role of β‐amyloid in causing AD. Most important, our results strongly suggest that to develop γ‐secretase inhibitors for the pharmacological treatment of AD may be not a reasonable strategy because antagonism of presenilin function may worsen neurodegeneration. © 2008 Wiley‐Liss, Inc.
Trophic factors and neuronal interactions regulate the cell cycle and Pax6 expression in Müller stem cells
Authors: Insua M. Fernanda , Simón M. Victoria , Garelli Andrés , de los Santos Beatriz , Rotstein Nora P. , Politi Luis E.
Published: January 2008

The finding that Müller cells have stem cell properties in the retina has led to the hypothesis that they might be a source for replacing neurons lost in neurodegenerative diseases. However, utilization of Müller cells for regenerative purposes in the mammalian eye still requires identifying those factors that regulate their multipotentiality and proliferation. In addition, because Pax6 expression is indispensable for eye development, its regulation would be required during regeneration. In the present study we investigated the regulation of cell‐cycle progression and Pax6 expression in pure Müller glial cell cultures and neuroglial cocultures from rat retinas. At early times in vitro, glial cells showed high expression of Pax6 and of nestin, a stem cell marker, and of markers of cell‐cycle progression; expression of these markers decreased during development in parallel with increased glial differentiation. The addition of glial‐derived neurotrophic factor, basic fibroblast growth factor, and insulin restored proliferation and also Pax6 and nestin expression in glial cells. Noteworthy, in neuroglial cocultures Müller cells retained Pax6 expression for longer periods, and, in turn, neuronal progenitors preserved their proliferative potential for several days in vitro. This suggests that neuroglial interactions mutually regulate their mitogenic capacity. In addition, in glial secondary cultures incubated with insulin, many neuroblast‐like cells expressed the neuronal marker NeuN. Our results suggest that the proliferative capacity and the features of eye stem cells of Müller glial cells are regulated by molecular and cellular factors, which might then provide potential tools for manipulating retinal regeneration. © 2008 Wiley‐Liss, Inc.
Early postnatal development of rat brain: In vivo diffusion tensor imaging
Authors: Bockhorst K.H. , Narayana P.A. , Liu R. , Ahobila‐Vijjula P. , Ramu J. , Kamel M. , Wosik J. , Bockhorst T. , Hahn K. , Hasan K.M. , Perez‐Polo J.R.
Published: January 2008

Perinatal hypoxia is a major cause of neurodevelopmental deficits. Neuronal migration patterns are particularly sensitive to perinatal hypoxia/ischemia and are associated with the clinical deficits. The rat model of hypoxia/ischemia at P7 mimics that of perinatal injury in humans. Before assessing the effects of postnatal injury on brain development, it is essential to determine the normal developmental trajectories of various brain structures in individual animals. In vivo longitudinal diffusion tensor imaging (DTI) was performed from postnatal day 0 (P0) to P56 on Wistar rats. The DTI metrics, mean diffusivity (MD), fractional anisotropy (FA), axial (λl) and radial (λt) diffusivities, were determined for four gray matter and eight white matter structures. The FA of the cortical plate and the body of corpus callosum decreased significantly during the first 3 weeks after birth. The decrease in the cortical plate's FA value was associated mainly with an increase in λt. The initial decrease in FA of corpus callosum was associated with a significant decrease in λl. The FA of corpus callosum increased during the rest of the observational period, which was mainly associated with a decrease in λt. The FA of gray matter structures, hippocampus, caudate putamen, and cortical mantle did not show significant changes between P0 and P56. In contrast, the majority of white matter structures showed significant changes between P0 and P56. These temporal changes in the DTI metrics were related to the neuronal and axonal pruning and myelination that are known to occur in the developing brain. © 2008 Wiley‐Liss, Inc.
The Inventory of Depressive Symptomatology: German translation and psychometric validation
Authors: Drieling T. , Schärer L.O. , Langosch J.M.
Published: January 2008

The Inventory of Depressive Symptomatology (IDS) is a rating scale for depression, widely used in international multicentre studies. There are two corresponding versions: a self‐rated (IDS‐SR) and a clinician‐rated (IDS‐C) scale. The aim of this study was to evaluate the reliability and validity of the German versions of the IDS‐SR and IDS‐C in comparison to the Hamilton Rating Scale for Depression (HRSD) and to the Beck Depression Inventory (BDI). The sample consisted of 59 inpatients and outpatients treated for unipolar or bipolar disorders. Internal consistency of the IDS‐SR and IDS‐C was found highly acceptable (α = 0.94 and α = 0.93). Item‐total‐correlations of the IDS‐SR revealed that 68% of the items were strongly correlated with the sum score (≥0.50). This was in the same range with the IDS‐C (54%), the HRSD (53%) and the BDI (76%). Furthermore, there is a high concurrent validity (r ≥ 0.88) of the IDS‐SR with the IDS‐C, the BDI and the HRSD. Substantial score‐differences between inpatients and outpatients indicate a good discriminant validity. It is concluded that the German version of the IDS is a useful instrument for the assessment of depressive symptoms and that it has the same highly acceptable psychometric properties as the original English version. Copyright © 2008 John Wiley & Sons, Ltd.
Kinematic models for the thickness of oceanic crust at and near mid‐oceanic spreading centers
Authors: Ruedas Thomas , Schmeling Harro
Published: January 2008

We consider analytical solutions for different cases of the one‐dimensional equation of mass transport as applied to an idealized mid‐oceanic spreading center in order to assess the conditions for the existence of thickness variations in oceanic crust and their possible magnitude. Models with an internally homogeneous crust suggest that in order to achieve the near‐constant crustal thickness of oceanic crust, the zones of volcanic accretion and of deformation must be more or less identical, especially if the far‐field plate velocity is not reached near the ridge in a jump‐like fashion, but increases more slowly over a certain distance; this indicates that accretion and strain are physically coupled. If crustal accretion occurs in a narrower strip around the spreading center than does deformation, there will be a maximum of thickness within the strain zone which is greater than the thickness far away from the ridge; if the accretion zone is broader than the zone of deformation, the near‐axis realms will have thinned crust throughout. A discontinuity of the plate velocity across the spreading axis causes a central strip of strongly thinned crust and generally damps variations in crustal thickness. An internally tripartite oceanic crust will almost unavoidably show some thickness variations near the spreading center. Transport by diffusive crustal flow is generally not of great importance at normal ridges, but may have some significance in thickened crust near hot spots. Although the solutions are restricted to the steady state, they show that the mere interaction of a few geometrical characteristics of the crust can produce a wide range of thickness variations in the regions near the spreading center.
Static and dynamic characterization of alluvial deposits in the Tiber River Valley: New data for assessing potential ground motion in the City of Rome
Authors: Bozzano F. , Caserta A. , Govoni A. , Marra F. , Martino S.
Published: January 2008

The paper presents the results of a case study conducted on the Holocene alluvial deposits of the Tiber River valley, in the city of Rome. The main test site selected for the study, Valco S. Paolo, is located about 2 km South of Rome's historical centre. The alluvial deposits were dynamically characterized in a comprehensive way via site investigations and geotechnical laboratory tests. Normalized shear modulus decay and damping curves (G/G0 and D/D0 vs γ) were obtained for the dominantly fine‐grained levels. The curves demonstrate that these levels have a more marked shear stiffness decay if compared with the underlying Pliocene bedrock. Decay curves from laboratory tests for the Tiber alluvia correlated well with the trend of the function proposed by Hardin and Drnevich, making it possible to derive their specific interpolation function coefficients. Use was made of the extrapolation of the findings from the Valco S. Paolo test site to a large part of Rome's historical centre by means of two other test sites, supported by an engineering‐geology model of the complex spatial distribution of the Tiber alluvia. The experimental Valco S. Paolo Vs profile was extrapolated to the other test sites on the basis of a stratigraphic criterion; the analysis of seismic noise measurements, obtained for the three test sites, validated the engineering‐geology based extrapolation and showed that the main rigidity contrast occurs inside the alluvial body (at the contact with the underlying basal gravel‐level G) and not between the alluvia and the Plio‐Pleistocene bedrock, composed of highly consistent clay (Marne Vaticane). The 1D modeling of local seismic response to the maximum expected earthquakes in the city of Rome confirms that the deposits have one principal mode of vibration at about 1 Hz. However, the simulation also evidenced that the silty‐clay deposits (level C), making up the most part of the Tiber alluvial body, play a key role in characterizing the soil column deformation profile since it can be affected by non linear effects induced by the maximum expected earthquake when some stratigraphic conditions are satisfied.
Coeval extensional shearing and lateral underflow during Late Cretaceous core complex development in the Niğde Massif, Central Anatolia, Turkey
Authors: Gautier Pierre , Bozkurt Erdin , Bosse Valérie , Hallot Erwan , Dirik Kadir
Published: January 2008

The Niğde Massif, at the southern tip of the Central Anatolian Crystalline Complex, consists of two structural units. Foliations in the lower unit define a dome cored by migmatites. The contact between the two units bears all the elements of a ductile to brittle extensional detachment. Hence the Niğde Massif represents an extensional metamorphic core complex. Top‐to‐NE/ENE shearing at higher levels of the lower unit relates to displacement along the detachment. Deeper levels of the lower unit display high‐temperature top‐to‐SSW ductile shearing. The two shearing deformations show a difference in the mean trend of stretching lineations of up to 58°. New 40Ar/39Ar ages combined with previously published data enable us to infer that the two shears were contemporaneous. In our favored interpretation, oblique shearing in the core of the dome reflects lateral underflow, i.e., horizontal flowing of the lower crust in a direction highly oblique to the direction of extension. As a result of the interaction between lateral underflow and downdip shearing along the overlying detachment, distinct structural domains are expected to exist within the migmatitic part of the core complex, with observed counterparts in the Niğde dome. Lateral underflow may reflect “inward” flow on the scale of the core complex. Regional‐scale channel flow is an alternative that would better account for the record of non‐coaxial deformation in the core of the dome. More generally, we suspect that the development of lateral underflow in a metamorphic core complex more likely reflects regional channel flow, rather than local inward flow.
Climatic cycles as expressed in sediments of the PROMESS1 borehole PRAD1‐2, central Adriatic, for the last 370 ka: 1. Integrated stratigraphy
Authors: Piva Andrea , Asioli Alessandra , Schneider Ralph R. , Trincardi Fabio , Andersen Nils , Colmenero‐Hidalgo Elena , Dennielou Bernard , Flores José‐Abel , Vigliotti Luigi
Published: January 2008

A multiproxy integrated chronological framework, based on oxygen and carbon stable isotope stratigraphy, biostratigraphy (foraminifera and nannoplankton bioevents and foraminifer assemblage‐based climate cyclicity), magnetostratigraphy, sapropel stratigraphy, and 14C AMS radiometric dates, has been achieved for borehole PRAD1‐2, collected in 185.5 m water depth in the central Adriatic. This work was carried out within the European Community project Profiles across Mediterranean Sedimentary Systems (PROMESS1). The 71.2 m long borehole spans a time interval between late MIS 11 and MIS 1 (the last 370 ka), showing a chronological resolution of 500 and 250 years per cm during interglacial and glacial intervals, respectively. At present, this record is the most expanded and continuous marine record available for the Adriatic Basin. Several orbital cycles can be recognized in the PRAD1‐2 record: the 100 ka glacial‐interglacial fluctuations and the 23 ka precession‐related cycles, which in turn control the deposition of sapropel layers. An integrated analysis of short‐term oscillations within the Last Glaciation interval (MIS 4–MIS 2) allowed the identification of the Adriatic signature of Dansgaard‐Oeschger events, showing the potential to achieve a more refined chronostratigraphic framework for the top part of the PRAD1‐2 record. Finally, the age model obtained by this study allowed the chronological integration of the main foraminifera bioevents detected in the borehole as well as of the volcanoclastic layers present in the upper part of the record. Despite its proximal location, PRAD1‐2 presents a continuous record and shows the potential to be consistently correlated both with deep‐sea and continental records in the Mediterranean region and beyond.
High‐resolution aeromagnetic data over central Australia assist Grenville‐era (1300–1100 Ma) Rodinia reconstructions
Authors: Aitken Alan R. A. , Betts Peter G.
Published: January 2008

High resolution aeromagnetic data covering the polydeformed and poorly exposed Musgrave Province of Australia reveals the Grenville‐aged crustal architecture. A combination of upward continuation and the potential field tilt filter out magnetic anomalies relating to a late Neoproterozoic orogenic event, and emphasize the more subtle magnetic structural grain formed during the ca. 1320–1150 Ma Musgravian Orogeny. The resulting images indicate that crustal architecture is defined by the distribution of ca. 1150 Ma magnetic granitoids within less magnetic basement and is dominantly northeast trending, continuous beneath the Amadeus and Officer basins, and defines an orogenic belt that connects Mesoproterozoic provinces. The orogenic belt is truncated within Australia and precludes a direct east trending connection between the Musgrave Province and contemporaneous orogens in Laurentia. Clockwise rotation of the South Australian Craton and subsequent collision with the North and West Australian cratons is our preferred model to explain the Grenville‐aged architecture observed in Australia.
The principal modes of variability of the boreal winter Hadley cell
Authors: Ma Jie , Li Jianping
Published: January 2008

The year‐to‐year variability of the boreal winter mass stream function of the mean meridional circulation (MMC) is dominated by an equatorially asymmetric mode and a symmetric mode. The former (latter) mode is linked with the boreal Hadley cell mainly on the decadal (interannual) time‐scale. The asymmetric mode index (AMI), which indicates the strength of this mode, shows a clear upward trend during the last decades of the 20th century. The strong sea surface temperature (SST) warming in the tropical Indo‐west Pacific warm‐pool might be an important factor contributing to the intensification of the asymmetric mode, and the SST warming in the southern tropical Atlantic Ocean and southeast Pacific may also contribute to this intensification. The symmetric mode index (SMI) shows a significant interannual variability that has a very robust and consistent correlation with ENSO, implying that the variability of the Hadley cell is mainly associated with ENSO on the interannual time‐scale. Additionally, the symmetric mode variability is also connected with the SST in the tropical Indo‐west Pacific warm‐pool.
Discovery of very large amplitude whistler‐mode waves in Earth's radiation belts
Authors: Cattell C. , Wygant J. R. , Goetz K. , Kersten K. , Kellogg P. J. , von Rosenvinge T. , Bale S. D. , Roth I. , Temerin M. , Hudson M. K. , Mewaldt R. A. , Wiedenbeck M. , Maksimovic M. , Ergun R. , Acuna M. , Russell C. T.
Published: January 2008

During a passage through the Earth's dawn‐side outer radiation belt, whistler‐mode waves with amplitudes up to more than ∼240 mV/m were observed by the STEREO S/WAVES instrument. These waves are an order of magnitude larger than previously observed for whistlers in the radiation belt. Although the peak frequency is similar to whistler chorus, there are distinct differences from chorus, in addition to the larger amplitudes, including the lack of drift in frequency and the oblique propagation with a large longitudinal electric field component. Simulations show that these large amplitude waves can energize an electron by the order of an MeV in less than 0.1s, explaining the rapid enhancement in electron intensities observed between the STEREO‐B and STEREO‐A passage during this event. Our results show that the usual theoretical models of electron energization and scattering via small‐amplitude waves, with timescales of hours to days, may be inadequate for understanding radiation belt dynamics.
Globally nonsimultaneous Forbush decrease events and their implications
Authors: Oh Su Yeon , Yi Yu , Kim Yong Ha
Published: January 2008

Forbush decrease (FD) events are supposed to happen simultaneously over the globe of the Earth. However, there have been several reports on nonsimultaneous FD events. We investigate for the first time the properties of nonsimultaneous FD events and the solar wind conditions causing such events in detail in order to determine what solar wind conditions lead to global simultaneity of FD events. We examined the hourly data of the Oulu Neutron Monitor (NM) station from 1998 to 2002. We have selected 49 FD events that have greater than 3.5% intensity reductions. Global simultaneity was determined by comparing the time profiles of these FD events with those recorded by other NM stations at Inuvik and Magadan. These three NM stations are located at close magnetic latitude (cutoff rigidity) but fairly evenly spaced in longitudes. The solar wind parameters driving FD event main phase are studied. Most FD event onsets (37 out of 49) are observed simultaneously by each NM station in universal time (UT) regardless of the location of the station, whereas some other FD events are not simultaneously detected but are at similar local times (LT). The stronger FD events tend to be simultaneous events, but the weaker FD events are nonsimultaneous. The simultaneous FD events are caused by the solar wind of higher speed and stronger IMF, whereas the nonsimultaneous events are driven by relatively lower speed and weaker IMF solar wind. The nonsimultaneous FD event may occur only if the main phase of the FD is superposed in phase with the declining phase of diurnal variation. Our interpretation is that the simultaneous FD events might occur when the high‐speed strong magnetic barrier (interplanetary shock sheath and magnetic cloud) overtakes the Earth, whereas the nonsimultaneous FD events may occur only when the slow‐moving weak magnetic barrier passes by on the duskside of the Earth. The global simultaneity of FD events depends on speed and IMF strength of solar wind overtaking Earth's magnetosphere and its propagation direction. This model of FD simultaneity can be tested by the STEREO mission.
Magnetic flux emergence in the Sun
Authors: Archontis V.
Published: January 2008

Space weather research is closely connected with the study of the solar magnetic activity. In past years, many solar missions (e.g., YOHKOH, SOHO, TRACE, and RHESSI) have provided outstanding observations, which have been used to improve our understanding of the structure and the dynamical evolution of solar magnetic fields. In addition, the newly launched solar missions (e.g., Hinode and STEREO) will study the interaction between the emerging magnetic field and the preexisting field in the corona (increasing our understanding of the causes of solar variability), and they will also observe the three‐dimensional evolution of solar eruptions as they leave the Sun and move into the interplanetary space. One of the most important processes, responsible for many dynamical phenomena observed in the Sun, is the emergence of magnetic flux from the solar interior in active regions and the modification of the coronal magnetic field in response to the emergence. In fact, magnetic flux emergence might be responsible for the appearance of small‐scale events (e.g., compact flares, plasmoids, and active‐region‐associated X‐ray brightenings) and large‐scale events (e.g., X‐class flares and CMEs), which are major drivers of space weather. However, it is clear that the question of how exactly the magnetic fields rise through the convection zone of the Sun and emerge through the photosphere and chromosphere into the corona has still not been solved. It is believed that understanding the process of flux emergence is an important step toward the understanding of the initiation mechanism of eruptive events in the Sun, which is another topic of great debate. This paper provides a brief review of the theory and the numerical models, which have been used to study the process of magnetic flux emergence into the outer atmosphere of the Sun. We underline the similarities and differences between these models, and we compare the basic features of the numerical results with observations. Finally, we review the recent progress and discuss what further developments are required in the models to best describe the essential physics in the process of flux emergence.
Fault plane orientations of intermediate‐depth earthquakes in the Middle America Trench
Authors: Warren Linda M. , Langstaff Meredith A. , Silver Paul G.
Published: January 2008

Intermediate‐depth earthquakes are often attributed to dehydration embrittlement reactivating preexisting weak zones. The orientation of presubduction faults is particularly well known offshore of Middle America, where seismic reflection profiles show outer rise faults dipping toward the trench and extending >20 km into the lithosphere. If water is transported along these faults and incorporated into hydrous minerals, the faults may be reactivated later when the minerals dehydrate. In this case, the fault plane orientations should be the same in the outer rise and at depth, after accounting for the angle of subduction. To test this hypothesis, we analyze the directivity of 54 large (MW ≥ 5.7) earthquakes between 35 and 220 km depth in the Middle America Trench. For 12 of these earthquakes, the directivity vector allows us to identify the fault plane of the focal mechanism. Between 35 and 85 km depth, we observe both subhorizontal and subvertical fault planes. The subvertical fault planes are consistent with the reactivation of outer rise faults, whereas the subhorizontal fault planes suggest the formation of new faults. Deeper than 85 km, we only observe subhorizontal faults, indicating that the outer rise faults are no longer being reactivated. The similarity with previous results from the colder Tonga‐Kermadec subduction zone suggests that the mechanism generating these earthquakes, and controlling fault plane orientations, depends on pressure rather than temperature or other tectonic parameters and that the observed rupture characteristics constitute a basic feature of intermediate‐depth seismicity. Exclusively subhorizontal faults may result from isobaric rupture propagation or the hindrance of seismic slip on preexisting weak subvertical planes.
Fast‐ice distribution in East Antarctica during 1997 and 1999 determined using RADARSAT data
Authors: Giles A. Barry , Massom Robert A. , Lytle Victoria I.
Published: January 2008

We present the first detailed maps of fast ice around East Antarctica (75°E–170°E), using an image correlation technique applied to RADARSAT ScanSAR images from November in 1997 and 1999. This method is based upon searching for, and distinguishing, correlated regions of the ice‐covered ocean which remain stationary, in contrast to adjacent moving pack ice. Within the overlapping longitudinal range of ∼86°E–150.6°E, the total fast‐ice area is 141,450 km2 in 1997 and 152,216 km2 in 1999. Calibrated radar backscatter data are also used to determine the distribution of two fast‐ice classes based on their surface roughness characteristics. These are “smooth” fast ice (−25.4 dB to −13.5 dB) and “rough” fast ice (−13.5 dB to −2.5 dB). The former comprises ∼67% of the total area, with rough fast ice making up the remaining ∼33%. An estimate is made of fast‐ice volume, on the basis of fast‐ice type as a proxy measure of ice thickness and area. Results suggest that although fast ice forms 2–16% of the total November sea ice area for this sector of East Antarctica in 1997 and 1999 (average 8.3% across maps), it may comprise 6–57% of the total ice volume (average ∼28% across maps). Grounded icebergs play a key role in fast‐ice distribution in all regions apart from 150°E–170°E. These are “snapshot” estimates only, and more work is required to determine longer‐term spatiotemporal variability.
A global monthly land surface air temperature analysis for 1948–present
Authors: Fan Yun , van den Dool Huug
Published: January 2008

A station observation‐based global land monthly mean surface air temperature dataset at 0.5 × 0.5 latitude‐longitude resolution for the period from 1948 to the present was developed recently at the Climate Prediction Center, National Centers for Environmental Prediction. This data set is different from some existing surface air temperature data sets in: (1) using a combination of two large individual data sets of station observations collected from the Global Historical Climatology Network version 2 and the Climate Anomaly Monitoring System (GHCN + CAMS), so it can be regularly updated in near real time with plenty of stations and (2) some unique interpolation methods, such as the anomaly interpolation approach with spatially‐temporally varying temperature lapse rates derived from the observation‐based Reanalysis for topographic adjustment. When compared with several existing observation‐based land surface air temperature data sets, the preliminary results show that the quality of this new GHCN + CAMS land surface air temperature analysis is reasonably good and the new data set can capture most common temporal‐spatial features in the observed climatology and anomaly fields over both regional and global domains. The study also reveals that there are clear biases between the observed surface air temperature and the existing Reanalysis data sets, and they vary in space and seasons. Therefore the Reanalysis 2 m temperature data sets may not be suitable for model forcing and validation. The GHCN + CAMS data set will be mainly used as one of land surface meteorological forcing inputs to derive other land surface variables, such as soil moisture, evaporation, surface runoff, snow accumulation and snow melt, etc. As a byproduct, this monthly mean surface air temperature data set can also be applied to monitor surface air temperature variations over global land routinely or to verify the performance of model simulation and prediction.