bluuebunny/crossref_metadata_2025 huggingface dataset:
''Geopolymers": same basic chemistry, different microstructures
Authors: Palomo A. , Fernández-Jiménez A. , Criado M.
Published: June 2010

The present paper describes the effect of certain working variables on the microstructural evolution of oven-dried, alkali-activated fly ash. The results show that the main reaction product in the activation process (in all the systems studied) is an amorphous aluminosilicate gel with a three-dimensional structure. Nonetheless, the type and concentration of the activator used as well as the natural ageing of the materials and origin of the prime materials were also found to have a substantial impact on microstructural development in the "geopolymers " synthesised, particularly from the morphological standpoint.
Is the clay "exchange capacity" concept wholly applicable to pozzolans?
Authors: Talero R.
Published: June 2010

One of the most characteristic properties of clays is their "cation exchange capacity", otherwise known as their "exchange capacity ". The research reported in this article shows that for various reasons some natural and artificial pozzolans exhibit this property. Ion exchange is only partial in the latter however because contrary to clays, on hydration with Portland cement, pozzolans may he nearly entirely converted from their mainly vitreous and/or amorphous original state into a variety of new more or less crystalline compounds. For this purpose a total of 142 types of cement were tested in this study: 8 industrial and 134 laboratory cements, the latter prepared by mixing Portland cements with different proportions, by weight, of three natural and three artificial pozzolans. All these cements were analysed by the Frattini test, 7 and/or 28 days after mixing. Both [OH-] and [CaO] and the percentage content of Na+ and K+ expressed as Na2O and K2O, respectively, were determined in liquid phase. The cation concentration was only determined for the 45 blended cements most relevant to the objective of the study. Finally, the three natural pozzolans were analyzed by XRD to identify their mineral composition. The results obtained confirmed the working hypothesis. They also showed that the higher the content of Na+ and/or K+ the higher the likelihood of exchange capacity in the pozzolans. in this case primarily with Ca2+ Nonetheless, the very special mineral composition of certain pozzolans, with minerals such as zeolite and phillipsite, may likewise contribute to this capacity. In any event, due to the cation exchange between Na+/ K+ and Ca+ the blended cements involved met the Frattini test requirements more readily and had shorter setting times, especially: - where the Portland cement with which they were mixed was not highly sulphate-resistant, and - where the Portland cement/pozzolan ratio was 60/40. Under these circumstances the behaviour of one of the pozzolans studied may, in one sense, be described to be ''more apparent than real ".
Saturated salt method determination of hysteresis of Pinus sylvestris L. wood for 35 ºC isotherms
Authors: García Esteban L. , Guindeo Casasús A. , De Palacios P. , García Fernández F.
Published: June 2010

The saturated salts method was used in this study to quantify hysteresis in Pinus sylvestris L. wood, in an exercise that involved plotting the 35 ºC desorption and sorption isotherms. Nine salts were used, all of which establish stable and known relative humidity values when saturated in water The wood was kept at the relative humidity generated by each of these salts until the equilibrium moisture content (EMC) was reached, both in the water loss or desorption, and the water uptake or sorption processes. The Guggenheim method was used to fit the values obtained to the respective curves. Hysteresis was evaluated in terms of the hysteresis coefficient, for which a mean value of 0.87 was found.
Stability of superplasticizer and shrinkage-reducing admixtures
Stability of superplasticizer and shrinkage-reducing admixtures in high basic media
Authors: Palacios M. , Puertas F.
Published: June 2010

The present study explores the stability of different superplasticizer (polycarboxylate, vinyl copolymers, melamine and naphthalene derivatives) and shrinkage-reducing (polyproplyene glycol derivatives) admixtures in water and several alkaline media: NaOH (pH= 11.7 and 13.6), Ca(OH)2 (pH=l2.4) and waterglass (pH=13.0) solutions. The pH of the solutions was measured at different limes and the structural changes taking place in the admixtures were studied using FTIR, FT-Raman and UV-VIS techniques. All the admixtures, except the naphthalene and polypropylenglycol derivatives in the NaOH pH=l3.6 solution and the naphthalene derivative in waterglass (NaO2-nSiO2-mH2O + NaOH), are unstable at pH > 13.0. The other admixtures all undergo structural changes in highly basic media that explain the loss of their fluidifying properties under these conditions.
Effect of chemical treatments on the mechanical properties of peanut shell and cement blends
Authors: Gatani M. , Argüello R. , Sesín S.
Published: June 2010

An abundance of agri-food waste in the area around Cordoba, Argentina, has driven the development of new construction materials. This study explored the applicability of peanut shells as additions in cement blends and the suitability of the properties of the resulting mixes for use in construction materials.

The mechanical properties of the specimens were observed to improve when the shells were previously treated with quicklime (CaO) or when sodium silicate and aluminium sulphate were added to the blend.

While the resulting materials did not exhibit the same mechanical properties as traditional mortars and concretes, they do appear to be apt for use in lightweight and non-bearing structures.
Production, Purification, and Characterization of Polygalacturonase fromMucor circinelloidesITCC 6025
Authors: Thakur Akhilesh , Pahwa Roma , Singh Smarika , Gupta Reena
Published: June 2010

Mucor circinelloidesproduced an extracellular polygalacturonase enzyme, the production of which was enhanced when various production parameters were optimized. Maximum polygalacturonase (PGase) activity was obtained in 48 h at30∘Cand pH 4.0 with pectin methyl ester (1% w/v) as carbon source and a combination of casein hydrolysate (0.1% w/v) and yeast extract (0.1% w/v) as nitrogen source. The enzyme was purified to homogeneity (13.3-fold) by Sephacryl S-100 gel-filtration chromatography. Its molecular weight was 66 kDa on SDS-PAGE. The enzyme was found to haveKmandVmaxvalues of 2.2 mM and 4.81 IU/ml at 0.1% to 0.5% (w/v) concentration of the substrate. The addition of phenolic acids (0.05 mM), metal ions such as Mn+2, Co+2, Mg+2,Fe+3,Al+3, Hg+2, and Cu+2, and thiols had inhibitory effect on the enzyme. The enzyme showed maximum activity in the presence of polygalacturonic acid (0.1% w/v) at pH 5.5 and42∘C.
Methodology for the Systematic Reviews of Occupational Therapy for Children and Adolescents With Difficulty Processing and Integrating Sensory Information
Authors: Arbesman Marian , Lieberman Deborah
Published: June 2010

Systematic reviews of literature relevant to children and adolescents with difficulty processing and integrating sensory information are important to the practice of occupational therapy in this area. This article explains the five questions that were developed and served as the focus for these reviews: neuronal plasticity, subtyping, sensory integration and non–sensory integration occupational therapy interventions, and occupational performance for this population. Presented are the background for the reviews; the process followed for each question, including search terms and search strategy; the databases searched; and the methods used to summarize and critically appraise the literature. The final number of articles included in each systematic review, a summary of the results of the review, the strengths and limitations of the review, and implications for practice, education, and research are described.
Examining the Neuroscience Evidence for Sensory-Driven Neuroplasticity: Implications for Sensory-Based Occupational Therapy for Children and Adolescents
Authors: Lane Shelly J. , Schaaf Roseann C.
Published: June 2010

When Ayres first presented the theory of sensory integration (SI), she grounded it in the neuroscience literature. Neuroplasticity was then, and is today, considered to be at the heart of this theory. This evidence-based review sought to critically examine the basic science literature to specifically identify evidence for the assumptions and tenets of Ayres’ theory of SI. We reviewed literature between 1964 and 2005, within psychological, physiological, and biomedical areas, addressing neuroplasticity. The review focused on sensorimotor-based neuroplasticity; explored the data that addressed the links among sensory input, brain function, and behavior; and evaluated its relevance in terms of supporting or refuting the theoretical premise of occupational therapy using an SI framework (OT/SI) to treatment. Although direct application from basic science to OT/SI is not feasible, we concluded that there was a basis for the assumptions of Ayes’ SI theory.
Systematic Review of the Research Evidence Examining the Effectiveness of Interventions Using a Sensory Integrative Approach for Children
Authors: May-Benson Teresa A. , Koomar Jane A.
Published: June 2010

Twenty-seven studies were systematically reviewed to identify, evaluate, and synthesize the research literature on the effectiveness of sensory integration (SI) intervention on the ability of children with difficulty processing and integrating sensory information to engage in desired occupations and to apply these findings to occupational therapy practice. Results suggest the SI approach may result in positive outcomes in sensorimotor skills and motor planning; socialization, attention, and behavioral regulation; reading-related skills; participation in active play; and achievement of individualized goals. Gross motor skills, self-esteem, and reading gains may be sustained from 3 mo to 2 yr. Findings may be limited by Type II error because of small sample sizes, variable intervention dosage, lack of fidelity to intervention, and selection of outcomes that may not be meaningful to clients and families or may not change with amount of treatment provided. Replication of findings with methodologically and theoretically sound studies is needed to support current findings.
Performance Challenges for Children and Adolescents With Difficulty Processing and Integrating Sensory Information: A Systematic Review
Authors: Koenig Kristie Patten , Rudney Sarah G.
Published: June 2010

A systematic review of the literature related to performance difficulties for children and adolescents with difficulty processing and integrating sensory information was completed as part of the Evidence-Based Literature Review Project of the American Occupational Therapy Association. The review focused on functional performance difficulties that these children may exhibit in areas of occupation including play and leisure, social participation, activities of daily living, instrumental activities of daily living, rest and sleep, education, and work. The results suggest that children and adolescents with difficulty processing and integrating sensory information do exhibit functional performance difficulties in key areas of occupation. However, further descriptive studies are needed to tie these difficulties to their specific sensory and motor issues. Researchers are encouraged to include functional performance measures and measures of social participation in their studies to further elucidate these relationships.
Relationship Between Context and Sensory Processing in Children With Autism
Authors: Brown Natalie Bennett , Dunn Winnie
Published: June 2010

OBJECTIVE. The purpose of the study was to determine the relationship between sensory processing and context for children with autism. We examined home and school contexts using the Sensory Profile (Dunn, 1999) and the Sensory Profile School Companion (Dunn, 2006a) questionnaires.

METHOD. Teachers of 49 students with autism completed the Sensory Profile School Companion, and parents completed the Sensory Profile. We conducted correlational analyses using the avoiding and seeking quadrant scores from the School Companion and corresponding avoiding and seeking quadrant scores from the Sensory Profile.

RESULTS. The avoiding quadrant score coefficient (.59) and the seeking quadrant score coefficient (.45) were statistically significant (p = .01) with good and fair correlations, respectively, suggesting that sensory processing patterns have both universal qualities and context-specific qualities in children with autism.

CONCLUSION. Findings from this study provide initial evidence that sensory processing and context for children with autism are related.
Expressive Behavior in Parkinson’s Disease as a Function of Interview Context
Authors: Takahashi Kayoko , Tickle-Degnen Linda , Coster Wendy J. , Latham Nancy K.
Published: June 2010

OBJECTIVE. Parkinson’s disease affects the ability to express motivation through face, body, and voice; contextual factors may facilitate or inhibit expressive behavior. The purpose of this study was to determine whether qualities of the interview context are associated with client motivational behavior in Parkinson’s disease.

METHOD. Men and women with Parkinson’s disease (N = 106) discussed 2 topics (enjoyable activity vs. frustrating activity) during an assessment with a female or male interviewer. From videotaped clips, displays of 4 categories of motivation and 12 verbal and 18 nonverbal behavioral patterns were rated.

RESULTS. During the discussion of enjoyable activities, participants used more positive words, smiled more, and were more facially expressive. Participants were less talkative about their negative feelings and appeared to be more apathetic with the same-gender interviewer.

CONCLUSION. Occupational therapy practitioners should vary the emotional tone of their questions to improve the validity of motivation assessments.
Taking the Floor: Oral Presentations in EFL Classrooms
Authors: AL‐ISSA ALI SAID , AL‐QUBTAN REDHA
Published: June 2010

This article discusses theoretical and practical aspects pertaining to oral presentations in the EFL context. It discusses issues and proposes ideas concerning the advantages of presentations, types of presentations, ways of arranging presentations in the classroom, possible topics of presentations and sources of data and information obtained for the different topics, and ways of assessing presentations in the EFL classroom. However, the discussion also has implications for non‐EFL contexts, including ESL, content‐based language learning, and learning languages other than English.
1+1 Does Not Always Equal 2: Exploring Creativity, Language Learning, and Technology‐Mediated Field Experience
Authors: HUH KEUN , EGBERT JOY
Published: June 2010

It is essential that preservice teachers and language learners understand why creativity is important and how creative thinking skills might be enhanced during language and content study. It is equally important that learners be given opportunities to express themselves creatively and that they are supported in doing so. To meet these goals, teacher education students must have practice working with English language learners around creativity. This is important even for preservice teachers who lack local access to ESL students. This exploration, part of a larger study of language, creativity, and computer‐mediated communication, describes the opportunities for preservice teachers to learn about student creativity and language use that an online field experience supported.
Writing With Power, Sharing Their Immigrant Stories: Adult ESOL Students Find Their Voices Through Writing
Authors: STEWART MARY AMANDA
Published: June 2010

After noting the disconnect between students' passionate oral stories and their lifeless writing, an adult education instructor made specific instructional and curriculum changes in an ESOL reading and writing course. All changes served the purpose of teaching the element of voice in second language writing. The instructor used the issue of immigration to teach the course because it was a relevant and shared experience of all the students. All of the reading material was about the immigrant experience, which became a catalyst for students' writing about their own experiences. Students wrote to share with others what it is like to be an immigrant and the unique challenges they encounter. The class compiled their essays, short stories, and poetry to make a book that speaks to the issue of immigration. The relevant theme proved to be effective in motivating students to infuse voice into their writing and exciting them about reading and writing in English. Through writing with voice, they took control to define themselves as immigrants in the United States and became empowered to share their stories to effect positive change.
Circumpolar measurements of speciated mercury, ozone and carbon monoxide in the boundary layer of the Arctic Ocean
Authors: Sommar J. , Andersson M. E. , Jacobi H.-W.
Published: June 2010

Abstract. Using the Swedish icebreaker Oden as a platform, continuous measurements of airborne mercury (gaseous elemental mercury (Hg0), divalent gaseous mercury species HgIIX2(g) (acronym RGM) and mercury attached to particles (PHg)) and some long-lived trace gases (carbon monoxide CO and ozone O3) were performed over the North Atlantic and the Arctic Ocean. The measurements were performed for nearly three months (July–September 2005) during the Beringia 2005 expedition (from Göteborg, Sweden via the proper Northwest Passage to the Beringia region Alaska – Chukchi Penninsula – Wrangel Island and in-turn via a north-polar transect to Longyearbyen, Spitsbergen). The Beringia 2005 expedition was the first time that these species have been measured during summer over the Arctic Ocean going from 60° to 90° N. During the North Atlantic transect, concentration levels of Hg0, CO and O3 were measured comparable to typical levels for the ambient mid-hemispheric average. However, a rapid increase of Hg0 in air and surface water was observed when entering the ice-covered waters of the Canadian Arctic archipelago. Large parts of the measured waters were supersaturated with respect to Hg0, reflecting a strong disequilibrium. Heading through the sea ice of the Arctic Ocean, a fraction of the strong Hg0 pulse in the water was transferred with some time-delay into the air samples collected ~20 m above sea level. Several episodes of elevated Hg0 in air were encountered along the sea ice route with higher mean concentration (1.81±0.43 ng m−3) compared to the marine boundary layer over ice-free Arctic oceanic waters (1.55±0.21 ng m−3). In addition, the bulk of the variance in the temporal series of Hg0 concentrations was observed during July. The Oden Hg0 observations compare in this aspect very favourably with those at the coastal station Alert. Atmospheric boundary layer O3 mixing ratios decreased when initially sailing northward. In the Arctic, an O3 minimum around 15–20 ppbV was observed during summer (July–August). Alongside the polar transect during the beginning of autumn, a steady trend of increasing O3 mixing ratios was measured returning to initial levels of the expedition (>30 ppbV). Ambient CO was fairly stable (84±12 ppbV) during the expedition. However, from the Beaufort Sea and moving onwards steadily increasing CO mixing ratios were observed (0.3 ppbV day−1). On a comparison with coeval archived CO and O3 data from the Arctic coastal strip monitoring sites Barrow and Alert, the observations from Oden indicate these species to be homogeneously distributed over the Arctic Ocean. Neither correlated low ozone and Hg0 events nor elevated concentrations of RGM and PHg were at any extent sampled, suggesting that atmospheric mercury deposition to the Arctic basin is low during the Polar summer and autumn.
The hygroscopicity parameter (κ) of ambient organic aerosol at a field site subject to biogenic and anthropogenic influences: relationship to degree of aerosol oxidation
Authors: Chang R. Y.-W. , Slowik J. G. , Shantz N. C. , Vlasenko A. , Liggio J. , Sjostedt S. J. , Leaitch W. R. , Abbatt J. P. D.
Published: June 2010

Abstract. Cloud condensation nuclei (CCN) concentrations were measured at Egbert, a rural site in Ontario, Canada during the spring of 2007. The CCN concentrations were compared to values predicted from the aerosol chemical composition and size distribution using κ-Köhler theory, with the specific goal of this work being to determine the hygroscopic parameter (κ) of the oxygenated organic component of the aerosol, assuming that oxygenation drives the hygroscopicity for the entire organic fraction of the aerosol. The hygroscopicity of the oxygenated fraction of the organic component, as determined by an Aerodyne aerosol mass spectrometer (AMS), was characterised by two methods. First, positive matrix factorization (PMF) was used to separate oxygenated and unoxygenated organic aerosol factors. By assuming that the unoxygenated factor is completely non-hygroscopic and by varying κ of the oxygenated factor so that the predicted and measured CCN concentrations are internally consistent and in good agreement, κ of the oxygenated organic factor was found to be 0.22±0.04 for the suite of measurements made during this five-week campaign. In a second, equivalent approach, we continue to assume that the unoxygenated component of the aerosol, with a mole ratio of atomic oxygen to atomic carbon (O/C) ≈ 0, is completely non-hygroscopic, and we postulate a simple linear relationship between κorg and O/C. Under these assumptions, the κ of the entire organic component for bulk aerosols measured by the AMS can be parameterised as κorg=(0.29±0.05)·(O/C), for the range of O/C observed in this study (0.3 to 0.6). These results are averaged over our five-week study at one location using only the AMS for composition analysis. Empirically, our measurements are consistent with κorg generally increasing with increasing particle oxygenation, but high uncertainties preclude us from testing this hypothesis. Lastly, we examine select periods of different aerosol composition, corresponding to different air mass histories, to determine the generality of the campaign-wide findings described above.
Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment
Authors: Salma I. , Borsós T. , Weidinger T. , Aalto P. , Hussein T. , Dal Maso M. , Kulmala M.
Published: June 2010

Abstract. Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6–1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8×103 to 29×103 cm−3 with a yearly median of 11.8×103 cm−3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79±6)%. Daily average number concentrations in various size fractions and contribution of ultrafine particles to the total particle number showed no seasonal dependency. Monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. Median diameters of the Aitken and accumulation modes were shifted to larger values before nucleation started and over the growth process, which can be related to the presence of aged aerosol under the conditions that favour nucleation and growth. Particle concentrations were usually increased substantially after nucleations. Overall mean and standard deviation of the nucleation mode number concentrations were (10.4±2.8)×103 cm−3. Mean ratio and standard deviation of the nucleation mode number concentration to the total particle number concentration that was averaged for two hours just before the formation was detected was 2.3±1.1. Nucleation unambiguously occurred on 83 days, which represent 27% of all relevant days. Its frequency showed a remarkable seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. Formation rate of particles with a diameter of 6 nm varied between 1.65 and 12.5 cm−3 s−1 with a mean and standard deviation of (4.2±2.5) cm−3 s−1. Seasonal dependency for the formation rate could not be identified. Growth curves of nucleated particles were usually superimposed on the characteristic diurnal pattern of road traffic direct emissions. The growth rate of the nucleation mode with a median diameter of 6 nm varied from 2.0 to 13.3 nm h−1 with a mean and standard deviation of (7.7±2.4) nm h−1. There was an indicative tendency for larger growth rates in summer and for smaller values in winter. Several indirect evidences suggest that the nucleation events occurred at least over the whole city, and were of regional type.
Quantitative sampling and analysis of trace elements in ambient air: impactor characterization and Synchrotron-XRF mass calibration
Authors: Richard A. , Bukowiecki N. , Lienemann P. , Furger M. , Weideli B. , Fierz M. , Minguillón M. C. , Figi R. , Flechsig U. , Appel K. , Prévôt A. S. H. , Baltensperger U.
Published: June 2010

Abstract. Identification of trace elements in ambient air can add substantial information to pollution source apportionment studies, although they do not contribute significantly to emissions in terms of mass. A method for quantitative size and time-resolved trace element evaluation in ambient aerosols with a rotating drum impactor and synchrotron radiation based X-ray fluorescence is presented. The impactor collection efficiency curves and size segregation characteristics were investigated in an experiment with oil and salt particles. Cutoff diameters were determined through the ratio of size distributions measured with two particles sizers. Furthermore, an external calibration technique to empirically link fluorescence intensities to ambient concentrations was developed. Solutions of elemental standards were applied with an ink-jet printer on thin films and area concentrations were subsequently evaluated with external wet chemical methods. These customized and reusable reference standards enable quantification of different data sets analyzed under varying experimental conditions.
Fast time-resolved aerosol collector: proof of concept
Authors: Yu X.-Y. , Cowin J. P. , Iedema M. J. , Ali H.
Published: June 2010

Abstract. Atmospheric particles can be collected in the field on substrates for subsequent laboratory analysis via chemically sensitive single particle methods such as scanning electron microscopy with energy dispersive x-ray analysis. With moving substrates time resolution of seconds to minutes can be achieved. In this paper, we demonstrate how to increase the time resolution when collecting particles on a substrate to a few milliseconds to provide real-time information. Our fast time-resolved aerosol collector ("Fast-TRAC") microscopically observes the particle collection on a substrate and records an on-line video. Particle arrivals are resolved to within a single frame (4–17 ms in this setup), and the spatial locations are matched to the subsequent single particle analysis. This approach also provides in-situ information on particle size and number concentration. Applications are expected in airborne studies of cloud microstructure, pollution plumes, and surface long-term monitoring.
Effects of the solar eclipse on 15 January 2010 on the surface O3, NO, NO2, NH3, CO mixing ratio and the meteorological parameters at Thiruvanathapuram, India
Authors: Sharma S. K. , Mandal T. K. , Arya B. C. , Saxena M. , Shukla D. K. , Mukherjee A. , Bhatnagar R. P. , Nath S. , Yadav S. , Gautam R. , Saud T.
Published: June 2010

Abstract. In this paper, we present the effect of total solar eclipse on surface O3, NO, NO2, NH3, CO mixing ratio and the meteorological parameters on 15 January 2010 at Thiruvanathapuram, India. On the day of total solar eclipse (i.e., 15 January 2010), the decrease in mixing ratio of surface O3 and NO2 is observed after the beginning of the solar eclipse events (11:15 to 15:30). Decrease in surface O3 may be due to decreased efficiency of the photochemical ozone formation, whereas, mixing ratio of NO and NH3 have been changed following the night time chemistry. Surface O3 reduced to 20.3 ppb after 22 min of full phase of the eclipse. During the solar eclipse period, the ambient temperature and wind speed have decreased, whereas, relative humidity has increased as expected.
Substorm-related thermospheric density and wind disturbances derived from CHAMP observations
Authors: Ritter P. , Lühr H. , Doornbos E.
Published: June 2010

Abstract. The input of energy and momentum from the magnetosphere is most efficiently coupled into the high latitude ionosphere-thermosphere. The phenomenon we are focusing on here is the magnetospheric substorm. This paper presents substorm related observations of the thermosphere derived from the CHAMP satellite. With its sensitive accelerometer the satellite can measure the air density and zonal winds. Based on a large number of substorm events the average high and low latitude thermospheric response to substorm onsets was deduced. During magnetic substorms the thermospheric density is enhanced first at high latitudes. Then the disturbance travels at an average speed of 650 m/s to lower latitudes, and 3–4 h later the bulge reaches the equator on the night side. Under the influence of the Coriolis force the travelling atmospheric disturbance (TAD) is deflected westward. In accordance with present-day atmospheric models the disturbance zonal wind velocities during substorms are close to zero near the equator before midnight and attain moderate westward velocities after midnight. In general, the wind system is only weakly perturbed (Δvy<20 m/s) by substorms.
3-D-geocoronal hydrogen density derived from TWINS Ly-α-data
Authors: Zoennchen J. H. , Nass U. , Lay G. , Fahr H. J.
Published: June 2010

Abstract. Based on Ly-α-line-of-sight measurements taken with two Ly-α detectors onboard of the satellite TWINS1 (Two Wide-angle Imaging Neutral-atom Spectrometers) density profiles of the exospheric, neutral geocoronal hydrogen were derived for the time period between summer solstice and fall equinox 2008. With the help of specifically developed inversion programs from Ly-α line of sight intensities the three-dimensional density structure of the geocoronal hydrogen at geocentric distances r>3 RE could be derived for the period mentioned characterized by very low solar 10.7 cm radiofluxes of ≈65–70 [10−22 W m−2 Hz−1]. The time-variable, solar "line-centered"-Ly-α-flux was extracted on the basis of daily (terrestrial) NGDC 10.7 cm radioflux data using the models from Barth et al. (1990) and Vidal-Madjar (1975). The results for the geocoronal H-densities are compared here both with theoretical calculations based on a Monte-Carlo model by Hodges (1994) and with density profiles obtained with the Geocoronal Imager (GEO) by Østgaard and Mende (2003). In our results we find a remarkably more pronounced day-/night-side asymmetry which clearly hints to the existence of a hydrogen geotail (i.e. a tail structure with comparatively higher hydrogen densities on the night side of the earth for geocenctric distances >4 RE), and a only weakly pronounced polar depletion. These unexpected features we try to explain by new models in the near future. The derived 3-D-H-density structures are able to explain the line-of-sight (LOS) dependent Ly-α intensity variations for all LOS seen up to now with TWINS-LAD. The presented results are valid for the region with geocentric distances 3 RE<r<7 RE and are based on the reasonable assumption of an optically thin H-exosphere with respect to resonant Ly-α-scattering allowing the use of single scattering calculations.
Fueling primary productivity: nutrient return pathways from the deep ocean and their dependence on the Meridional Overturning Circulation
Authors: Palter J. B. , Sarmiento J. L. , Gnanadesikan A. , Simeon J. , Slater D.
Published: June 2010

Abstract. In the Southern Ocean, mixing and upwelling in the presence of heat and freshwater surface fluxes transform subpycnocline water to lighter densities as part of the upward branch of the Meridional Overturning Circulation (MOC). One hypothesized impact of this transformation is the restoration of nutrients to the global pycnocline, without which biological productivity at low latitudes would be catastrophically reduced. Here we use a novel set of modeling experiments to explore the causes and consequences of the Southern Ocean nutrient return pathway. Specifically, we quantify the contribution to global productivity of nutrients that rise from the ocean interior in the Southern Ocean, the northern high latitudes, and by mixing across the low latitude pycnocline. In addition, we evaluate how the strength of the Southern Ocean winds and the parameterizations of subgridscale processes change the dominant nutrient return pathways in the ocean. Our results suggest that nutrients upwelled from the deep ocean in the Antarctic Circumpolar Current and subducted in Subantartic Mode Water support between 33 and 75% of global primary productivity between 30° S and 30° N. The high end of this range results from an ocean model in which the MOC is driven primarily by wind-induced Southern Ocean upwelling, a configuration favored due to its fidelity to tracer data, while the low end results from an MOC driven by high diapycnal diffusivity in the pycnocline. In all models, the high preformed nutrients subducted in the SAMW layer are converted rapidly (in less than 40 years) to remineralized nutrients, explaining previous modeling results that showed little influence of the drawdown of SAMW surface nutrients on atmospheric carbon concentrations.
Past dynamics of the Australian monsoon: precession, phase and links to the global monsoon
Authors: Beaufort L. , van der Kaars S. , Bassinot F. C. , Moron V.
Published: June 2010

Abstract. Past variations in the dynamics of the Australian monsoon have been estimated from multi-proxy analysis of a core retrieved in the Eastern Banda Sea. Records of coccolith and pollen assemblages, spanning the last 150,000 years, allow reconstruction of past primary production in the Banda Sea, summer moisture availability, and the length of the dry season in Northern Australia and Southeastern Indonesia. The amount of moisture available during the summer monsoon follows typical glacial/interglacial dynamics with a broad asymmetrical 100-kyr cycle. Primary production and length of the dry season appear to be closely related, given that they follow the precessional cycle with the same phase (August insolation). This indicates their independence from ice-volume variations. The present inter-annual variability of both parameters is related to El Niño Southern Oscillation (ENSO), which modulates the Australian Winter Monsoon (AWM). The precessional pattern observed in the past dynamics of the AWM is found in ENSO and monsoon records of other regions. A marked shift in the monsoon intensity occurring during the mid Holocene during a period of constant ice volume, suggest that low latitude climatic variation precedes global ice volume. This precessional pattern suggests that a common forcing mechanism underlies low latitude climate dynamics, acting specifically and synchronically on the different monsoon systems.
The application of GIS based decision-tree models for generating the spatial distribution of hydromorphic organic landscapes in relation to digital terrain data
Authors: Bou Kheir R. , Bøcher P. K. , Greve M. B. , Greve M. H.
Published: June 2010

Abstract. Accurate information about organic/mineral soil occurrence is a prerequisite for many land resources management applications (including climate change mitigation). This paper aims at investigating the potential of using geomorphometrical analysis and decision tree modeling to predict the geographic distribution of hydromorphic organic landscapes in unsampled area in Denmark. Nine primary (elevation, slope angle, slope aspect, plan curvature, profile curvature, tangent curvature, flow direction, flow accumulation, and specific catchment area) and one secondary (steady-state topographic wetness index) topographic parameters were generated from Digital Elevation Models (DEMs) acquired using airborne LIDAR (Light Detection and Ranging) systems. They were used along with existing digital data collected from other sources (soil type, geological substrate and landscape type) to explain organic/mineral field measurements in hydromorphic landscapes of the Danish area chosen. A large number of tree-based classification models (186) were developed using (1) all of the parameters, (2) the primary DEM-derived topographic (morphological/hydrological) parameters only, (3) selected pairs of parameters and (4) excluding each parameter one at a time from the potential pool of predictor parameters. The best classification tree model (with the lowest misclassification error and the smallest number of terminal nodes and predictor parameters) combined the steady-state topographic wetness index and soil type, and explained 68% of the variability in organic/mineral field measurements. The overall accuracy of the predictive organic/inorganic landscapes' map produced (at 1:50 000 cartographic scale) using the best tree was estimated to be ca. 75%. The proposed classification-tree model is relatively simple, quick, realistic and practical, and it can be applied to other areas, thereby providing a tool to facilitate the implementation of pedological/hydrological plans for conservation and sustainable management. It is particularly useful when information about soil properties from conventional field surveys is limited.
Groundwater flow and storage within an alpine meadow-talus complex
Authors: McClymont A. F. , Hayashi M. , Bentley L. R. , Muir D. , Ernst E.
Published: June 2010

Abstract. The different types of geological deposits and rock formations found in alpine watersheds play key roles in regulating the rate and timing of runoff to mountain rivers. Talus and alpine meadows are dominant features in these areas, but scant data exist for their capacity to store and transmit groundwater. To gain further understanding of these processes, we have undertaken a combined geophysical and hydrological study of a small (2100 m2) alpine meadow and surrounding talus within the Lake O'Hara watershed in the Canadian Rockies. Several intersecting ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) profiles and a seismic refraction profile were acquired to map the thickness of the talus and to image the topography of the bedrock basin that underlies the meadow. From analysis of the GPR and seismic profiles, we estimate that the talus deposits are relatively thin (<6 m). Combined interpretations from the GPR and ERT data show that the fine-grained sediment comprising the meadow basin has a total volume of ca. 3300 m3 and has a maximum thickness of ca. 4 m. Annual snow surveys and stream gauging reveal that the total input volume of snowmelt and rainfall to the meadow basin is several times larger than its groundwater storage capacity, giving rise to low total-dissolved species concentrations (14–21 mg/L) within the meadow groundwater. Observations from four piezometers established on the meadow show that the water table fluctuates rapidly in response to spring snowmelt and precipitation events but otherwise maintains a relatively stable depth of 0.3–0.4 m below the meadow surface during summer months. A slug test performed on one of the piezometers indicated that the saturated hydraulic conductivity of the shallow meadow sediments is 2.5×10−7 m/s. We suggest that a bedrock saddle imaged underneath the southern end of the meadow forms a natural constriction to subsurface flow out of the basin and helps to maintain the stable water-table depth.
Plot and field scale soil moisture dynamics and subsurface wetness control on runoff generation in a headwater in the Ore Mountains
Authors: Zehe E. , Graeff T. , Morgner M. , Bauer A. , Bronstert A.
Published: June 2010

Abstract. This study presents an application of an innovative sampling strategy to assess soil moisture dynamics in a headwater of the Weißeritz in the German eastern Ore Mountains. A grassland site and a forested site were instrumented with two Spatial TDR clusters (STDR) that consist of 39 and 32 coated TDR probes of 60 cm length. Distributed time series of vertically averaged soil moisture data from both sites/ensembles were analyzed by statistical and geostatistical methods. Spatial variability and the spatial mean at the forested site were larger than at the grassland site. Furthermore, clustering of TDR probes in combination with long-term monitoring allowed identification of average spatial covariance structures at the small field scale for different wetness states. The correlation length of soil water content as well as the sill to nugget ratio at the grassland site increased with increasing average wetness and but, in contrast, were constant at the forested site. As soil properties at both the forested and grassland sites are extremely variable, this suggests that the correlation structure at the forested site is dominated by the pattern of throughfall and interception. We also found a very strong correlation between antecedent soil moisture at the forested site and runoff coefficients of rainfall-runoff events observed at gauge Rehefeld. Antecedent soil moisture at the forest site explains 92% of the variability in the runoff coefficients. By combining these results with a recession analysis we derived a first conceptual model of the dominant runoff mechanisms operating in this catchment. Finally, we employed a physically based hydrological model to shed light on the controls of soil- and plant morphological parameters on soil average soil moisture at the forested site and the grassland site, respectively. A homogeneous soil setup allowed, after fine tuning of plant morphological parameters, most of the time unbiased predictions of the observed average soil conditions observed at both field sites. We conclude that the proposed sampling strategy of clustering TDR probes is suitable to assess unbiased average soil moisture dynamics in critical functional units, in this case the forested site, which is a much better predictor for event scale runoff formation than pre-event discharge. Long term monitoring of such critical landscape elements could maybe yield valuable information for flood warning in headwaters. We thus think that STDR provides a good intersect of the advantages of permanent sampling and spatially highly resolved soil moisture sampling using mobile rods.
Preparation of DNA and RNA Fragments Containing Guanine N2‐Thioalkyl Tethers
Authors: Hou Xiaorong , Wang Gang , Gaffney Barbara L. , Jones Roger A.
Published: June 2010

This unit describes procedures for preparation of deoxyguanosine and guanosine derivatives in which the guanine N2 contains a thiopropyl tether, protected as a tert‐butyl disulfide. After incorporation into a DNA or RNA fragment, this tether allows site‐specific cross‐linking to a thiol of a protein or another nucleic acid. Curr. Protoc. Nucleic Acid Chem. 41:5.8.1‐5.8.23. © 2010 by John Wiley & Sons, Inc.
Reaktions‐Diffusions‐Systeme für intrazellulären Transport und Kontrolle
Authors: Soh Siowling , Byrska Marta , Kandere‐Grzybowska Kristiana , Grzybowski Bartosz A.
Published: June 2010

Chemische Reaktionen können Zellen nur am Leben erhalten, wenn die beteiligten Verbindungen an den erforderlichen Stellen zeitlich präzise angeliefert werden. Die meisten Forschungen haben sich bislang auf aktive Transportmechanismen konzentriert, obwohl die passive Diffusion oft gleich schnell ist und weniger Energie erfordert. Um die Vorteile dieser Transportform zu nutzen, haben die Zellen ausgeklügelte Reaktions‐Diffusions(RD)‐Systeme entwickelt, die zahlreiche zelluläre Funktionen kontrollieren – von Chemotaxis und Zellteilung über Signalkaskaden und ‐oszillationen bis hin zur Zellbeweglichkeit. Diese nur scheinbar unterschiedlichen Systeme sind nach allgemeinen Prinzipien aufgebaut und haben viele Gemeinsamkeiten. Wiederkehrende Elemente sind nichtlineare Kinetik, Autokatalyse und Rückkopplungsschleifen. Um die Funktion dieser komplexen (bio)chemischen Systeme zu verstehen, muss man die Transportkinetik‐Gleichungen analysieren oder die charakteristischen Zeiten der Teilprozesse zumindest qualitativ betrachten. Während wir Beispiele für zelluläre RD‐Systeme vorstellen, versuchen wir daher auch, den Leser mit den theoretischen Grundlagen der RD‐Phänomene vertraut zu machen.
Viral transformation for production of personalized type I interferons
Authors: Xu Dongsheng , Zhang Luwen
Published: June 2010

Type I interferons (IFN) are cytokines with many functions and have been widely used to treat many human diseases such as hepatitis C virus infection. Using the viral transformation and priming properties of Epstein‐Barr virus, we have developed a system that can produce high levels of “personalized” IFNs, which are produced from the cells of the patient to whom the IFNs are to be administrated. We demonstrate the feasibility of the system. This seems to be the first report for the establishment of a personalized IFN‐production system. The personalized IFNs could have a longer circulation time, fewer side effects but higher efficacy. We anticipate that the system can provide an improved form of IFN for medical uses.
Meeting report: Gene to vial concept for biotechnology based healthcare molecules
Authors: Vijayalakshmi M.A.
Published: June 2010

CBST‐VIT University, Vellore, India February 7–10, 2010
Liquid chromatography tandem mass spectrometry method for determination of N‐acetylcysteine in human plasma using an isotope‐labeled internal standard
Authors: Lu Chuan , Liu Gangyi , Jia Jingying , Gui Yuzhou , Liu Yanmei , Zhang Mengqi , Liu Yun , Li Shuijun , Yu Chen
Published: June 2010

A liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method was developed to determine total N‐acetylcysteine in human plasma. Mass spectrometric detection was achieved in positive electrospray ionization and multiple reaction monitoring mode. The mass transition pairs of N‐acetylcysteine and the isotope‐labeled internal standard d3‐N‐acetylcysteine were 164 → 122 and 167 → 123, respectively. The method was linear over the range of 10–5000 ng/mL in human plasma. The adoption of trichloroacetic acid significantly enhanced the extraction recovery. The blank matrix was screened to minimize the influence of endogenous N‐acetylcysteine. After being fully validated, the method was successfully applied to the pharmacokinetic and bioequivalent study of N‐acetylcysteine after oral administration of 600 mg tablets to 24 healthy Chinese volunteers. Copyright © 2010 John Wiley & Sons, Ltd.
ChemInform Abstract: Effect of Cation Size and Disorder on the Structure and Properties of the Rare Earth Cobaltates, Ln0.5M0.5CoO3 (Ln: Rare Earth, M: Sr, Ba).
Authors: Vanitha P. V. , Arulraj Anthony , Santhosh P. N. , Rao C. N. R.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Phase Stability of Yttria‐Stabilized Zirconia with Dissolved Cerium and Neptunium Oxides under Oxidizing and Reducing Atmospheres.
Authors: Kinoshita Hajime , Kuramoto Ken‐ichi , Uno Masayoshi , Yanagi Tadashi , Yamanaka Shinsuke , Mitamura Hisayoshi , Banba Tsumetaka
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.