bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct observation of salts as micro-inclusions in the Greenland GRIP ice core
Authors: Sakurai Toshimitsu , Iizuka Yoshinori , Horikawa Shinichiro , Johnsen Sigfús , Dahl-jensen Dorthe , Steffensen Jørgen Peder , Hondoh Takeo 
Published: December 2009

AbstractWe provide the first direct evidence that a number of water-soluble compounds, in particular calcium sulfate (CaSO4·2H2O) and calcium carbonate (CaCO3), are present as solid, micron-sized inclusions within the Greenland GRIP ice core. The compounds are detected by two independent methods: micro-Raman spectroscopy of a solid ice sample, and energy-dispersive X-ray spectroscopy of individual inclusions remaining after sublimation. CaSO4·2H2O is found in abundance throughout the Holocene and the last glacial period, while CaCO3 exists mainly in the glacial period ice. We also present size and spatial distributions of the micro-inclusions. These results suggest that water-soluble aerosols in the GRIP ice core are dependable proxies for past atmospheric conditions.
Volume-size distribution of microparticles in ice cores from the Tibetan Plateau
Authors: Wu Guangjian , Yao Tandong , Xu Baiqing , Tian Lide , Zhang Chenglong , Zhang Xuelei 
Published: December 2009

AbstractThe volume distribution of atmospheric dust particles (microparticles) of 1–30 μm diameter in Muztagata, Dunde, Dasuopu and Everest ice cores from the Tibetan Plateau was measured and fitted as a log-normal function in order to characterize their basic size properties. Our results reveal that whether the volume distribution fits the log-normal function or not largely depends on the dust concentration and the specific dust-storm event but is independent of physiographical location and season. Our results show only high-concentration samples obey the log-normal distribution in volume, with mode sizes ranging from 3 to 161 μm. The log-normal distribution was largely attributed to the mid-sized particles between 3 and 15 μm, which contribute most (>70%) of the total volume. The volume size distribution characteristics for mineral dust particles from ice cores reveal that the coarse particles might be common in the upper-level troposphere over the Tibetan Plateau. These dust size features are useful to advance our understanding of dust effects on climate, and provide clues to better characterize atmospheric dynamics over the Tibetan Plateau that will help to improve the current models.
Subglacial seismic reflection strategies when source amplitude and medium attenuation are poorly known
Authors: Holland Charles W. , Anandakrishnan Sridhar 
Published: December 2009

AbstractSeismic reflection techniques are a powerful way to probe physical properties of subglacial strata. Inversion of seismic data for physical properties may be hampered, however, by lack of knowledge of the source amplitude as well as lack of knowledge of the compressional and shear attenuation in the ice. New methods are described to measure the source signature that require no a priori knowledge of the ice attenuation profile. Another new method is described to obtain the angular dependence of the subglacial bed reflection coefficient that is relatively insensitive to knowledge of the ice attenuation. Finally, a correction is provided to a long-standing error in the literature regarding measurement of the bed normal incidence reflection coefficient.
Improving surface boundary conditions with focus on coupling snow densification and meltwater retention in large-scale ice-sheet models of Greenland
Authors: Fausto Robert S. , Ahlstrøm Andreas P. , Van as Dirk , Johnsen Sigfús J. , Langen Peter L. , Steffen Konrad 
Published: December 2009

AbstractSnowpack changes during the melt season are often not incorporated in modelling studies of the surface mass balance of the Greenland ice sheet. Densification of snow accelerates when meltwater is present, due to percolation and subsequent refreezing, and needs to be incorporated in ice-sheet models for ablation calculations. In this study, simple parameterizations to calculate surface melt, snow densification and meltwater retention are included as surface boundary conditions in a large-scale ice-sheet model of Greenland. Coupling the snow densification and meltwater-retention processes achieves a separation of volume and mass changes of the surface layer, in order to determine the surface melt contribution to runoff. Experiments for present-day conditions show that snow depth at the onset of melt, mean annual near-surface air temperature and the mean density of the annual snow layer are key factors controlling the quantity and spatial distribution of meltwater runoff above the equilibrium line on the Greenland ice sheet.
Chemical composition of fresh snow from Glaciar Marinelli, Tierra del Fuego, Chile
Authors: Grigholm B. , Mayewski P.A. , Kurbatov A.V. , Casassa Gino , Contreras Staeding A. , Handley M. , Sneed S.B. , Introne D.S. 
Published: December 2009

AbstractA fresh-snow sampling campaign was conducted during the late austral summer of 2006 in the accumulation zone of Glaciar Marinelli, located in the Cordillera Darwin, Tierra del Fuego, Chile. Snow samples were analyzed for stable isotopes (δ18O), major soluble ions (Na+, K+, Ca2+, Mg2+, Cl−, NO3−, SO42−, MS−) and major and trace elements (Na, Mg, Al, Fe, Ca, Sr, Cd, Cs, Ba, La, Ce, Pr, Dy, Ho, Er, Bi, U, As, Ti, V, Cr, Mn). The dominance of marine chemistry resembles that in studies from Patagonian glaciers. Snow chemistry was dominantly loaded by marine species (Cl−, Na+ and ssSO42−), while contributions of crustal species (e.g. Al and Fe) were very low. Empirical orthogonal function analysis suggests two possible dust sources, one represented by Al and Fe and the other by La, Ce and Pr. Enrichment-factor calculations suggest the majority of elements are within average upper-crustal ratios, but major enrichments of Bi and Cd (hundreds of times) suggest possible anthropogenic sources. Linear correlation of δ18O and barometric pressure (r = 0.60, p < 0.007) suggests a potential ‘amount effect’ relationship between depleted δ18O ratios and stronger storm conditions (e.g. greater precipitation). The snow-chemistry records from Glaciar Marinelli are the first measured in Tierra del Fuego, the southernmost glaciated region outside Antarctica.
Onset of calving at supraglacial lakes on debris-covered glaciers of the Nepal Himalaya
Authors: Sakai A. , Nishimura K. , Kadota T. , Takeuchi N. 
Published: December 2009

AbstractField surveys of supraglacial ponds on debris-covered glaciers in the Nepal Himalaya clarify that ice-cliff calving occurs when the fetch exceeds ∼80 m. Thermal undercutting is important for calving processes in glacial lakes, and subaqueous ice melt rates during the melt and freeze seasons are therefore estimated under simple geomorphologic conditions. In particular, we focus on the differences between valley wind-driven water currents in various fetches during the melt season. Our results demonstrate that the subaqueous ice melt rate exceeds the ice-cliff melt rate when the fetch is >20 m and water temperature is 2–4°C. Calculations suggest the onset of calving due to thermal undercutting is controlled by water currents driven by winds at the surface of the lake, which develop with expanding water surface.
A subglacial water-flow model for West Antarctica
Authors: Le Brocq A.M. , Payne A.J. , Siegert M.J. , Alley R.B. 
Published: December 2009

AbstractThe current generation of continental-scale ice-sheet models cannot successfully reproduce the complex ice/water/sediment interactions of the West Antarctic ice sheet (WAIS) in a physically meaningful manner. The potential of a thin-film-based subglacial water-flow model for incorporation into a continental-scale coupled ice/water flow model of the WAIS is evaluated in this paper. The subglacial water-flow model is applied to the Ross Sea sector of the WAIS, in both a steady-state and time-dependent form, to derive the equilibrium water depth for the present-day configuration. The potential for coupling the model to an ice-flow model is then demonstrated, using a variable sliding parameter that is a function of the subglacial water depth. A coupled ice/water flow model, using the parameterization tested in this paper, could have the potential for reproducing the surface elevation, velocity and thermal regime of the WAIS successfully. These requirements are crucial in modelling the evolution of the WAIS, and must be addressed before reliable continental-scale predictive models can be utilized.
Stability algorithm for snow micro-penetrometer measurements
Authors: Bellaire Sascha , Pielmeier Christine , Schneebeli Martin , Schweizer Jürg 
Published: December 2009

AbstractInformation on snow-cover stability is important for predicting avalanche danger. Traditionally, stability evaluation is based on manual observations of snow stratigraphy and stability tests, which are time-consuming. The SnowMicroPen (SMP) is a high-resolution, constant-speed penetrometer to measure penetration resistance. We have analysed the resistance signal to derive snow stability. The proposed stability algorithm was developed by comparing 68 SMP force–distance profiles with the corresponding manual profiles, including stability tests. The algorithm identifies a set of four potentially weak layers by taking into account changes in structure and rupture strength of microstructural elements that make up snow layers as derived from the SMP signal. In 90% of the cases, one of the four potentially weak layers proposed by the algorithm coincided with the failure layer observed in the stability test. To select the critical layer from the four potential weaknesses was more difficult. With fully automatic picking of the critical layer, agreement with the failure layer observed in the stability test was reached in 60% of the cases. To derive a stability classification, we analysed weak-layer as well as slab properties. These predictor variables allow the SMP signal to be classified into two stability classes, poor and fair-to-good, with an accuracy of ∼75% when compared with observed stability. The SMP, in combination with the proposed algorithm, shows high potential for providing snow-cover stability information at high resolution in time and space.
Adults with Auditory Neuropathy: Comparison of Auditory Steady-State Response and Pure-Tone Audiometry
Authors: Jafari Zahra , Malayeri Saeed , Ashayeri Hassan , Farahani Mahdi Azizabadi 
Published: December 2009

Background: The relation between the auditory steady-state response (ASSR) and behavioral audiometric thresholds requires further clarification in the case of adults with auditory neuropathy/auditory dys-synchrony (AN/AD). Purpose: The aim of this study was to compare
pure-tone audiometric threshold (PTAT) and ASSR in adults with AN/AD. Study Sample: Sixteen adult participants (32 ears) with AN/AD, ranging in age from 14 to 34 years. Data Collection and Analysis: PTAT and ASSR with high-rate stimulus modulation were measured at four octave
frequencies, 500, 1000, 2000, and 4000 Hz, in each ear. The behavioral auditory thresholds were compared with ASSR estimated thresholds at each frequency. Analyses included comparison of group means and coefficients of correlation. Results: The average pure-tone thresholds revealed
a moderate hearing loss in the AN/AD patients with a focus on the low frequencies. Low-frequency loss audiograms were observed in almost two-thirds of the participants. The estimated auditory thresholds measured by ASSR at all frequencies were substantially higher than the PTAT measures. There
were no significant correlations between the PTAT and ASSR measurements at the 1000, 2000, and 4000 Hz frequencies (p > .05); the correlation between the two measures at 500 Hz (p = .029, r = 0.39) was weak but significant. Conclusion:
There was no significant correlation between the PTAT and ASSR results at the majority of the frequencies usually tested in adults with AN/AD. Although ASSR is not a suitable method to estimate auditory thresholds in this group of patients, perhaps it can be utilized as an adjunct technique
for the differential diagnosis of this disorder.
Preparation and Analysis of Glycoconjugates
Authors: Varki Ajit , Freeze Hudson H. , Manzi Adriana E. 
Published: December 2009

AbstractWhereas DNA, RNA, and proteins are linear polymers that can usually be directly sequenced, glycans show substantially more complexity, having branching and anomeric configurations (α and β linkages). The biosynthesis of glycans, termed glycosylation, is extremely complex, is not template‐driven, varies among different cell types, and cannot be easily predicted from simple rules. This overview discusses the stereochemistry of mono‐ and oligosaccharides and provides diagrammatic representations of monosaccharides (Fisher projections and Haworth representations) and formulas for representation of glycan chains. A glossary of terms used in glycobiology is also provided. Curr. Protoc. Mol. Biol. 88:17.0.1‐17.0.12. © 2009 by John Wiley & Sons, Inc.
Histochemical Methods for the Diagnosis of Mitochondrial Diseases
Authors: Paepe Boel De , Bleecker Jan L. De , Coster Rudy Van 
Published: December 2009

AbstractThrough the process of oxidative phosphorylation (OXPHOS), mitochondria provide cells with required energy in the form of ATP. The organelle possesses its own genome (mtDNA), which encodes for part of the components needed (37 genes encoding either OXPHOS structural subunits or tRNAs and rRNAs). Nonetheless, the majority of structural OXPHOS components (as well as accessory proteins and proteins required for maintenance, replication, and expression of the mtDNA) are encoded by nuclear genes. Due to the dual genetic control and the large number of proteins involved, biogenesis and assembly of the OXPHOS system is complicated, and identifying a specific gene defect can be a difficult and time consuming task. This unit describes procedures for obtaining tissue sections and cell material suitable for histological evaluation of OXPHOS activity and integrity and immunodetection of the complexes in tissue from patients suspected of mitochondrial disease. Emphasis lies on the diagnostic potential of these techniques to differentiate mtDNA from nuclear mutations. Curr. Protoc. Hum. Genet. 63:19.2.1‐19.2.19. © 2009 by John Wiley & Sons, Inc.
Evaluation of the Mitochondrial Respiratory Chain and Oxidative Phosphorylation System Using Polarography and Spectrophotometric Enzyme Assays
Authors: Barrientos Antoni , Fontanesi Flavia , Díaz Francisca 
Published: December 2009

AbstractThe oxidative phosphorylation (OXPHOS) system consists of five multimeric complexes embedded in the mitochondrial inner membrane. They work in concert to drive the aerobic synthesis of ATP. Mitochondrial and nuclear DNA mutations affecting the accumulation and function of these enzymes are the most common cause of mitochondrial diseases and have also been associated with neurodegeneration and aging. For this reason, several approaches for the assessment of the OXPHOS system enzymes have been developed. Based on the methods described elsewhere, the assays describe methods that form a biochemical characterization of the OXPHOS system in cells and mitochondria isolated from cultured cells or tissues. Curr. Protoc. Hum. Genet. 63:19.3.1‐19.3.14. © 2009 by John Wiley & Sons, Inc.
Evaluation of the Mitochondrial Respiratory Chain and Oxidative Phosphorylation System Using Yeast Models of OXPHOS Deficiencies
Authors: Fontanesi Flavia , Diaz Francisca , Barrientos Antoni 
Published: December 2009

AbstractThe oxidative phosphorylation (OXPHOS) system consists of five multimeric complexes embedded in the mitochondrial inner membrane. They work in concert to drive the aerobic synthesis of ATP. Mitochondrial and nuclear DNA mutations affecting the accumulation and function of these enzymes are the most common cause of mitochondrial diseases and have also been associated with neurodegeneration and aging. Several approaches for the assessment of the OXPHOS system enzymes have been developed. Based on the methods described elsewhere, this unit describes the creation and study of yeast models of mitochondrial OXPHOS deficiencies. Curr. Protoc. Hum. Genet. 63:19.5.1‐19.5.20. © 2009 by John Wiley & Sons, Inc.
Pulse Width for Particle Sizing
Authors: Hoffman Robert A. 
Published: December 2009

AbstractThe widths of optical pulses in flow cytometry contain information about the size of particles. This size information is independent of many of the factors that affect light scatter as a measure of particle size, and any light scatter or fluorescence signal can be used to measure pulse width. For fluorescence signals, the pulse width can be predicted theoretically for many particle shapes, and quantitative size calibration is possible. To be a meaningful independent parameter, the pulse‐width measurement must be independent of the pulse amplitude. This unit provides protocols for determining the signal range over which amplitude independent pulse‐width measurements can be made and methods for calibrating the pulse‐width measurements to particle diameter. Calibration and application examples are provided and briefly discussed. Curr. Protoc. Cytom. 50:1.23.1‐1.23.17. © 2009 by John Wiley & Sons, Inc.
High‐Resolution Multiparameter DNA Flow Cytometry for the Detection and Sorting of Tumor and Stromal Subpopulations from Paraffin‐Embedded Tissues
Authors: Corver Willem E. , ter Haar Natalja T. 
Published: December 2009

AbstractThis unit contains a detailed protocol for the simultaneous flow cytometric measurement of tumor cells, stromal cells, and DNA content of formalin‐fixed, paraffin‐embedded (FFPE) tissues. The vimentin‐positive stromal cell fraction can be used as an internal reference for DNA content assessments. This allows clear detection of keratin‐positive tumor cells with a DNA index lower than 1.0 and of keratin‐positive tumor cells with a DNA close to 1.0 in overall DNA aneuploid samples, thus improved DNA ploidy assessment in FFPE carcinomas. Furthermore, the protocol is useful for studying molecular genetic alterations and intratumor heterogeneity in archival FFPE samples. Keratin‐positive tumor cell fractions can be flow‐sorted for further molecular genetic analysis, while DNA from the sorted vimentin‐positive stromal cells can serve as a reference when normal tissue of the patient is not available. Curr. Protoc. Cytom. 50:6.27.1‐6.27.21. © 2009 by John Wiley & Sons, Inc.
Extensions of the Representational Theory of Measurement
Authors: Finkelstein Ludwik 
Published: December 2009

Abstract
The article considers development points of the representational theory of measurement. It considers the measurement of an attribute that cannot be measured directly and shows how it can be measured through its relation to attributes for which there is a direct measurement process. Fundamentals of measurement in domains for which there is a well‐developed theory are outlined. Symbolic descriptions, which do not satisfy the conditions of measurement, are discussed.
Instrumentation Amplifiers
Authors: McGhee Joseph 
Published: December 2009

Abstract
The op‐amp forms the basis of many kinds of amplifiers used in early stages of sensing systems. In this article, the various kinds of op‐amps as models are developed. The differential‐input to single‐ and differential‐output types that led to the 2 and 3 op‐amp units are covered. How to specify instrumentation amplifiers is covered, before ending with ways to improve the common‐mode rejection ratio.
Dynamic Behavior of Closed‐Loop Systems
Authors: Sydenham Peter H. 
Published: December 2009

AbstractControl systems used in measuring systems can be built and made to work using intuition alone, but to get the best out of them needs application of mathematical modeling. This article covers the application of Laplace transforms in solving analytical equations of a typical control loop in order to find out the responses to the commonly occurring inputs of impulse, step, ramp, and sinusoid.
Relationship Between Systems in the Time and Frequency Domain
Authors: Woschni Eugen Georg 
Published: December 2009

Abstract
Systems can be described with the same values either in the time or in the frequency domain. Therefore, it is possible to convert one domain into the other. As treated in the article, the Laplace transform is the mathematical fundament of these conversions. More detail is provided than in the introduction given elsewhere. Typical signals and their Laplace transforms and the corresponding theorems of the Laplace transform are given. An application in solving an important example is demonstrated.
Culture and Isolation of Brain Tumor Initiating Cells
Authors: Lenkiewicz Monika , Li Na , Singh Sheila K. 
Published: December 2009

AbstractThis unit describes protocols for the culture and isolation of brain tumor initiating cells (BTIC). The cancer stem cell (CSC) hypothesis suggests that tumors are maintained exclusively by a rare fraction of cells that have stem cell properties. We applied culture conditions and assays originally used for normal neural stem cells (NSCs) in vitro to a variety of brain tumors. The BTIC were isolated by fluorescence activated cell sorting for the neural precursor cell surface marker CD133. Only the CD133+ brain tumor fraction contains cells capable of sphere formation and sustained self‐renewal in vitro, and tumor initiation in NOD‐SCID mouse brains. Therefore, CD133+ BTICs satisfy the definition of cancer stem cells in that they are able to generate a replica of the patient's tumor and they exhibit self‐renewal ability through serial retransplantation. This established that only a rare subset of brain tumor cells with stem cell properties are tumor‐initiating, and, in this unit, we describe their culture and isolation. Curr. Protoc. Stem Cell Biol. 11:3.3.1‐3.3.10. © 2009 by John Wiley & Sons, Inc.
Single‐Molecule Spectroscopy for Plastic Electronics: Materials Analysis from the Bottom‐Up
Authors: Lupton John M. 
Published: December 2009

Abstractπ‐conjugated polymers find a range of applications in electronic devices. These materials are generally highly disordered in terms of chain length and chain conformation, besides being influenced by a variety of chemical and physical defects. Although this characteristic can be of benefit in certain device applications, disorder severely complicates materials analysis. Accurate analytical techniques are, however, crucial to optimising synthetic procedures and assessing overall material purity. Fortunately, single‐molecule spectroscopic techniques have emerged as an unlikely but uniquely powerful approach to unraveling intrinsic material properties from the bottom up. Building on the success of such techniques in the life sciences, single‐molecule spectroscopy is finding increasing applicability in materials science, effectively enabling the dissection of the bulk down to the level of the individual molecular constituent. This article reviews recent progress in single molecule spectroscopy of conjugated polymers as used in organic electronics.