bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiographically sensitive mapping of climatological temperature and precipitation across the conterminous United States
Authors: Daly Christopher , Halbleib Michael , Smith Joseph I. , Gibson Wayne P. , Doggett Matthew K. , Taylor George H. , Curtis Jan , Pasteris Phillip P.
Published: March 2008

Spatial climate data sets of 1971–2000 mean monthly precipitation and minimum and maximum temperature were developed for the conterminous United States. These 30‐arcsec (∼800‐m) grids are the official spatial climate data sets of the U.S. Department of Agriculture. The PRISM (Parameter‐elevation Relationships on Independent Slopes Model) interpolation method was used to develop data sets that reflected, as closely as possible, the current state of knowledge of spatial climate patterns in the United States. PRISM calculates a climate–elevation regression for each digital elevation model (DEM) grid cell, and stations entering the regression are assigned weights based primarily on the physiographic similarity of the station to the grid cell. Factors considered are location, elevation, coastal proximity, topographic facet orientation, vertical atmospheric layer, topographic position, and orographic effectiveness of the terrain. Surface stations used in the analysis numbered nearly 13 000 for precipitation and 10 000 for temperature. Station data were spatially quality controlled, and short‐period‐of‐record averages adjusted to better reflect the 1971–2000 period.

PRISM interpolation uncertainties were estimated with cross‐validation (C‐V) mean absolute error (MAE) and the 70% prediction interval of the climate–elevation regression function. The two measures were not well correlated at the point level, but were similar when averaged over large regions. The PRISM data set was compared with the WorldClim and Daymet spatial climate data sets. The comparison demonstrated that using a relatively dense station data set and the physiographically sensitive PRISM interpolation process resulted in substantially improved climate grids over those of WorldClim and Daymet. The improvement varied, however, depending on the complexity of the region. Mountainous and coastal areas of the western United States, characterized by sparse data coverage, large elevation gradients, rain shadows, inversions, cold air drainage, and coastal effects, showed the greatest improvement. The PRISM data set benefited from a peer review procedure that incorporated local knowledge and data into the development process. Copyright © 2008 Royal Meteorological Society
Obesity in long‐term survivors of childhood acute lymphoblastic leukemia
Authors: Asner S. , Ammann R.A. , Ozsahin H. , Beck‐Popovic M. , von der Weid N.X.
Published: March 2008

Background

Childhood acute lymphoblastic leukemia (ALL) with current cure rates reaching 80% emphasizes the necessity to determine treatment related long‐term effects. The present study examines the prevalence of and the risk factors for overweight and obesity in a cohort of ALL survivors treated and living in the French speaking part of Switzerland.

Methods

In this retrospective two‐center study, height and weight of 54 patients diagnosed with ALL in first complete remission and treated with chemotherapy only were recorded at specified time points during treatment and off‐therapy. Body mass index (BMI) and its age‐ and gender‐adjusted standard deviation score (BMI‐SDS) were calculated for the patients and their parents separately. Overweight and obesity were defined by a threshold of BMI‐SDS >1.645 and BMI‐SDS >1.96, respectively.

Results

At last follow‐up, 16 (30%) of the 54 survivors were overweight and 10 (18%) were obese. The off‐treatment period was most at risk with 11 of the 16 becoming overweight and 9 of the 10 becoming obese during that period. Overweight/obesity at diagnosis and abnormal maternal BMI were significantly associated with abnormal weight at follow‐up, while age at diagnosis, gender, cumulative dose of steroids and paternal BMI showed no association.

Conclusions

Consistent with published evidence from other regions of the developed and developing world, there is a significant prevalence of obesity in young ALL survivors in the French speaking part of Switzerland. Factors significantly associated with this late effect were mostly related to the familial background rather than to the treatment components. Pediatr Blood Cancer 2008;51:118–122. © 2008 Wiley‐Liss, Inc.
Health‐related quality of life in sickle cell disease
Authors: Panepinto Julie A.
Published: March 2008

Advances in drug therapy, hematopoietic stem cell transplantation, and technology have improved the morbidity and survival for those with sickle cell disease. The effect of this modern therapy on the health‐related quality of life (HRQL) of those with sickle cell disease is not known. HRQL provides an assessment of how an illness, its complications, and its treatment are experienced by a patient. This review will examine prior work in HRQL in sickle cell disease and the rationale for utilizing HRQL as an outcome to measure impact of treatment. In addition, issues to consider when reporting HRQL will be presented. Pediatr Blood Cancer 2008;51:5–9. © 2008 Wiley‐Liss, Inc.
Refining homology models by combining replica‐exchange molecular dynamics and statistical potentials
Authors: Zhu Jiang , Fan Hao , Periole Xavier , Honig Barry , Mark Alan E.
Published: March 2008

A protocol is presented for the global refinement of homology models of proteins. It combines the advantages of temperature‐based replica‐exchange molecular dynamics (REMD) for conformational sampling and the use of statistical potentials for model selection. The protocol was tested using 21 models. Of these 14 were models of 10 small proteins for which high‐resolution crystal structures were available, the remainder were targets of the recent CASPR exercise. It was found that REMD in combination with currently available force fields could sample near‐native conformational states starting from high‐quality homology models. Conformations in which the backbone RMSD of secondary structure elements (SSE‐RMSD) was lower than the starting value by 0.5–1.0 Å were found for 15 out of the 21 cases (average 0.82 Å). Furthermore, when a simple scoring function consisting of two statistical potentials was used to rank the structures, one or more structures with SSE‐RMSD of at least 0.2 Å lower than the starting value was found among the five best ranked structures in 11 out of the 21 cases. The average improvement in SSE‐RMSD for the best models was 0.42 Å. However, none of the scoring functions tested identified the structures with the lowest SSE‐RMSD as the best models although all identified the native conformation as the one with lowest energy. This suggests that while the proposed protocol proved effective for the refinement of high‐quality models of small proteins scoring functions remain one of the major limiting factors in structure refinement. This and other aspects by which the methodology could be further improved are discussed. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Effects of ligand binding on the dynamics of rice nonspecific lipid transfer protein 1: A model from molecular simulations
Authors: Lai Yen‐Ting , Cheng Chao‐Sheng , Liu Yu‐Nan , Liu Yaw‐Jen , Lyu Ping‐Chiang
Published: March 2008

Plant nonspecific lipid transfer proteins (nsLTPs) are small, basic proteins constituted mainly of α‐helices and stabilized by four conserved disulfide bridges. They are characterized by the presence of a tunnel‐like hydrophobic cavity, capable of transferring various lipid molecules between lipid bilayers in vitro. In this study, molecular dynamics (MD) simulations were performed at room temperature to investigate the effects of lipid binding on the dynamic properties of rice nsLTP1. Rice nsLTP1, either in the free form or complexed with one or two lipids was subjected to MD simulations. The C‐terminal loop was very flexible both before and after lipid binding, as revealed by calculating the root‐mean‐square fluctuation. After lipid binding, the flexibility of some residues that were not in direct contact with lipid molecules increased significantly, indicating an increase of entropy in the region distal from the binding site. Essential dynamics analysis revealed clear differences in motion between unliganded and liganded rice nsLTP1s. In the free form of rice nsLTP1, loop1 exhibited the largest directional motion. This specific essential motion mode diminished after binding one or two lipid molecules. To verify the origin of the essential motion observed in the free form of rice nsLTP1, we performed multiple sequence alignments to probe the intrinsic motion encoded in the primary sequence. We found that the amino acid sequence of loop1 is highly conserved among plant nsLTP1s, thus revealing its functional importance during evolution. Furthermore, the sequence of loop1 is composed mainly of amino acids with short side chains. In this study, we show that MD simulations, together with essential dynamics analysis, can be used to determine structural and dynamic differences of rice nsLTP1 upon lipid binding. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Application of CCSD(T)/(ECP + GCM) for studying gas‐phase electron and proton affinities
Authors: Morgon Nelson H.
Published: March 2008

The aim of this work is to analyze high level [CCSD(T)/ECP + GCM] calculations employed to determine the electron and proton affinities (EA and PA) of a set of molecules. The basis sets were developed for pseudopotential using the GCM procedure. This technique is potentially useful for large molecules containing heavy atoms. It can be classified as a quantum chemistry composite method, and achieves similar performance to the Gaussian theory (G2, G3, and G4) and CBS methods at a lower computational cost. The root mean square deviations (δrmsd) of EA and PA, in comparison to the experimental results, obtained were 0.15 eV and 4.14 kJ mol−1, respectively. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
A theoretical study of methanol vinylation reaction mechanism
Authors: Vitkovskaya Nadezhda M. , Larionova Elena Yu. , Kobychev Vladimir B. , Kaempf Natalia V. , Trofimov Boris A.
Published: March 2008

The mechanism of base‐catalyzed nucleophilic addition of methanol to acetylene triple bond (vinylation) in dimethyl sulfoxide (DMSO) and methanol solution was studied using the MP2/6‐311++G**//B3LYP/6‐31G* calculations with solvent effects included via continuum model. The proton abstraction from methanol by nondissociated alkali in DMSO surrounding media to form alkali metal methoxides CH3OM (M = Li, Na, K) was found to occur with a negligible activation barrier. The reasons for facilitation of base‐catalyzed alcohol vinylation in the DMSO medium are discussed in the light of both poor solvation of methoxide ion and a specific coordination of reactants by nondissociated alkali in the MOH/DMSO mixtures. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
On the possible removal of nitrogen monoxide and carbon monoxide on copper ion‐exchanged montmorillonite: A DFT study
Authors: Briones‐Jurado Claudia , Agacino‐Valdés Esther
Published: March 2008

DFT calculations have been carried out in order to study the possibilities of Cu ion‐exchanged Montmorillonite to act as matrix in two important chemical processes: the possible NO bond breaking in NO molecule and the CO2 formation as the result of CO oxidation. The adsorptions of NO, CO and O2 on Cu+1‐Montmorillonite (Cu+1‐MMT) were modeled using the cluster methodology at the BLYP level of theory. The binding energies related with the adsorption processes of CO, NO and O2 were of −30, −26 and −13 kcal/mol, respectively; these results indicate that the corresponding processes are favored. Moreover, it was found that the oxidation of CO throughout a Langmuir‐Rideal type unimolecular mechanism is a highly favored process because the change of the electronic energy was of −166, 26 kcal mol−1. In relation to NO molecule, a coadsorption of a second molecule was attempted; the negative value of −19.56 kcal mol−1 for the change in the electronic energy suggests that a second NO molecule can also be adsorbed and probably a dimer of NO could be formed. According to the results we think that Cu ion‐exchanged Montmorillonite could be an interesting catalytic system to be tested in environmental applications. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Negative ion mode matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometric analysis of oligosaccharides using halide adducts and 9‐aminoacridine matrix
Authors: Becher Jana , Muck Alexander , Mithöfer Axel , Svatoš Aleš , Boland Wilhelm
Published: March 2008

9‐Aminoacridine was established as a matrix for the detection of neutral oligosaccharides in negative ion mode matrix‐assisted laser desorption/ionisation time‐of‐flight (MALDI‐TOF) mass spectrometry. Sodium iodide proved to be a useful additive inducing formation of stable iodide adducts of the analytes, in particular for oligosaccharides with a degree of polymerisation (DP) of three and higher. Lower oligomers (DP <3) and monosaccharides show more stable adducts with chloride ions. After optimisation of the sample preparation procedure, limits of quantitation were determined for α‐cyclodextrin and cellopentaose at 7 and 13 pmol, respectively, with a linear detector response over two concentration orders. The iodide additive could be successfully employed on MALDI‐TOF mass spectrometers with vacuum and atmospheric pressure ion sources. The value of the new method to solve biological problems has been demonstrated by the analysis of a mixture of β‐glucane elicitors isolated from the cell walls of Phytophthora sojae. Copyright © 2008 John Wiley & Sons, Ltd.
Development of a dual‐spray electrospray deposition system for matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Erb William J. , Owens Kevin G.
Published: March 2008

A new method of matrix‐assisted laser desorption/ionization (MALDI) sample preparation using a dual‐spray electrospray deposition system is demonstrated and employed for the investigation of gas‐phase cationization reactions in the MALDI plume. The dual‐spray electrospray system is found to increase the homogeneity of the sample similarly to that of a conventional single‐spray electrospray system. The dual‐spray electrospray system allows for intimate mixing of separately prepared sample components and results in improved quantitative results. The development of this device also leads to the possibility of mixing sample components prepared in different solvents without the need to be concerned with solvent miscibility. Copyright © 2008 John Wiley & Sons, Ltd.
Absolute quantification of cardiac troponin T by means of liquid chromatography/triple quadrupole tandem mass spectrometry
Authors: Cavaliere Chiara , Cucci Francesca , Guarino Chiara , Gubbiotti Riccardo , Samperi Roberto , Laganà Aldo
Published: March 2008

A liquid chromatography/tandem mass spectrometric method for absolute quantification of cardiac troponin T (cTnT) in mouse heart tissue is presented. Even in such a complex biological sample, the multiple reaction monitoring acquisition mode allowed the selective and sensitive determination of a specific peptide, obtained by cTnT enzymatic digestion. The concentration of this cTnT‐specific peptide was considered as a representation of the concentration of its parent protein. Quantification was carried out by means of the matrix‐matched calibration curve, constructed by adding the synthetic standard of the target peptide and another synthetic structurally analogous peptide as internal standard. Method identification limit and method quantification limit were estimated as 60 and 110 ng of cTnT per mg of total extracted proteins, respectively. The developed label‐free approach has been applied for the absolute quantitation of cTnT because of its diagnostic and prognostic value as cardiac disease marker. However, the method could be of general application, since it requires only the synthesis of two suitable peptides, a protein tryptic cleavage product and an internal standard. Copyright © 2008 John Wiley & Sons, Ltd.
Comparative performance of tripole and quadrupole ion guides at elevated pressure
Authors: Misharin Alexander S. , Moskovets Eugene , Gamage Chaminda M. , Doroshenko Vladimir M. , Vilkov Andrey N.
Published: March 2008

This study presents the first practical demonstration of an operational tripole ion guide. The transmission was measured for both the tripole and quadrupole ion guides at 1 Torr pressure. It was found that the quadrupole provides 2.5–3 times better ion transmission efficiency. Two different electric schemes for driving the tripole were tested. Similar transmission characteristics were obtained in both cases. A brief analysis of the tripole performance and ways to improve it is presented. Copyright © 2008 John Wiley & Sons, Ltd.
Numerical reconstruction of wavefront in phase‐shifting point diffraction interferometer by digital holography
Authors: Matsuura Toshiaki , Okagaki Satoru , Oshikane Yasushi , Inoue Haruyuki , Nakano Motohiro , Kataoka Toshihiko
Published: March 2008

A phase‐shifting point diffraction interferometer (PS/PDI) is applied for absolute surface figure measurement for large aperture optics. The intensity and phase distributions of measurement wavefront containing the surface figure profile are measured on the projection plane. The phase map gives the surface figure of the mirror. However, the wavefront reflected by the test mirror changes itself while propagating due to the surface figure of the mirror and the position of the point light source. The wavefront is different from the surface figure on the projection plane. For absolute surface profiling, the wavefront on the mirror has to be reconstructed from the measurement results. To reconstruct the wavefront digital holography has been studied. We have developed the numerical reconstruction method by using the Helmholtz–Kirchhoff formula. Spherical concave mirror measurements have been simulated to verify the availability. Ideal spherical mirror measurements, aspherical mirror measurements and a spherical mirror measurement in which the point light source was slightly displaced were simulated. As a result, the phase map on the projection plane did not fit the surface figure. It was also revealed that the light intensity distribution causes changes in the wavefront. In contrast, the reconstructed phase map on the mirror gave the real surface figure. For precise reconstruction the number of sampling on the projection plane must be increased. Copyright © 2008 John Wiley & Sons, Ltd.
Bayesian hierarchical modeling of drug stability data
Authors: Chen Jie , Zhong Jinglin , Nie Lei
Published: March 2008

Stability data are commonly analyzed using linear fixed or random effect model. The linear fixed effect model does not take into account the batch‐to‐batch variation, whereas the random effect model may suffer from the unreliable shelf‐life estimates due to small sample size. Moreover, both methods do not utilize any prior information that might have been available. In this article, we propose a Bayesian hierarchical approach to modeling drug stability data. Under this hierarchical structure, we first use Bayes factor to test the poolability of batches. Given the decision on poolability of batches, we then estimate the shelf‐life that applies to all batches. The approach is illustrated with two example data sets and its performance is compared in simulation studies with that of the commonly used frequentist methods. Copyright © 2008 John Wiley & Sons, Ltd.
On effect‐measure modification: Relationships among changes in the relative risk, odds ratio, and risk difference
Authors: Brumback Babette , Berg Arthur
Published: March 2008

It is well known that the presence or absence of effect‐measure modification depends upon the chosen measure. What is perhaps more disconcerting is that a positive change in one measure may be accompanied by a negative change in another. Therefore, research demonstrating that an effect is ‘stronger’ in one population when compared with another, but based on only one measure, for example, the odds ratio, may be difficult to interpret for researchers interested in another measure. The present article investigates relationships among changes in the relative risk, odds ratio, and risk difference from one stratum to another. Monte Carlo integration shows that the three measures change in the same direction for 78 or 89 per cent of the volume of the geometric space defined by the four underlying proportions, depending on whether the strata are presumed to share the same direction of effect or not. Analytic results are presented concerning necessary and sufficient conditions for the measures to change in opposite directions. In general, the conditions are seen to be quite complicated, though they do give way to some interesting results. For example, when exposure increases risk but all risks are less than 0.5, it is impossible for the relative risk and risk difference to change in the same direction but opposite to that of the odds ratio. Both data‐analytic and hypothetical examples are presented to demonstrate circumstances under which the measures change in opposite directions. Copyright © 2008 John Wiley & Sons, Ltd.
The influence of dietary fatty acids and environmental temperature on the fatty acid composition of teleost fish
Authors: Reiser Raymond , Stevenson Bernadette , Kayama Mitsu , Choudhury R. B. R. , Hood D. W.
Published: March 2008

Marine and fresh water fish were depleted of tissue unsaturated fatty acids to various degrees and subsequently presented with linoleic and linolenic acids at different dietary levels, at different temperatures, with and without other dietary fat.

Examination of the tissue fatty acids demonstrated that marine and fresh water fish do not differ between themselves or from other classes of animals in the following basic mechanisms of deposition and interconversions of dietary fatty acids:

The fish are readily depleted of tissue polyunsaturated fatty acids.

Dietary linoleic and linolenic acids are deposited, the former to a greater degree than the latter.

At high levels of linoleic or linolenic acids in the diet there is no significant degree of their conversion to the longer chain more highly unsaturated acids typical of marine oils.

At low levels of linoleic or linolenic acids in the tissues there is a significant, but slight, conversion to the longer chain acids at low environmental temperatures.

The increase in the level of linoleic acid in tissue lipids which accompanies increases in the dietary levels, quickly tapers off above dietary levels of 5%.

Temperature differences between 13 and 23C had little or no influence on the deposition or interconversion of polyunsaturated acids.

Dietary cottonseed oil, which contains cyclopropene fatty acids, produces an increase in tissue stearic acid in the fundulus.
The quantitative analysis of triglyceride mixtures by thin layer chromatography on silica impregnated with silver nitrate
Authors: Barrett C. B. , Dallas M. S. J. , Padley F. B.
Published: March 2008

The paper describes a procedure involving thin layer chromatography on silica impregnated with silver nitrate, which makes possible the separation of synthetic and natural glyceride mixtures into classes according to their degree of unsaturation, and within those classes the resolution of certain isomeric unsaturated glycerides. The separations depend upon the ability of compounds having an olefinic double bond to form co‐ordination complexes with the silver ion.

For qualitative analysis, developed chromatoplates are sprayed with dibromofluorescein. Reliable quantitative data may be obtained by charring the separated glycerides with phosphoric acid under carefully controlled conditions, and comparing the densities of the charred areas by means of a photodensitometer. Experiments with mixtures of pure synthetic glycerides revealed an error of less than 3%.

Glyceride compositions of a number of natural fats have been determined, and compared with compositions obtained by enzymetic hydrolysis of the same samples.
N‐Carbamylglutamate for neonatal hyperammonaemia in propionic acidaemia
Authors: Jones S. , Reed C. A. B. , Vijay S. , Walter J. H. , Morris A. A. M.
Published: March 2008

Hyperammonaemia is common in neonates with branched‐chain organic acidaemias, primarily due to the inhibition of N‐acetylglutamate (NAG) synthetase; NAG is an activator for carbamylphosphate synthetase I, the first enzyme of the urea cycle. N‐Carbamylglutamate, a NAG analogue, has been reported to correct hyperammonaemia in neonates with organic acidaemias. It is, however, uncertain how the ammonia concentrations in these neonates would have progressed without the drug. We report a neonate with propionic acidaemia, whose plasma ammonia concentration responded dramatically to N‐carbamylglutamate, having previously been over 950 μmol/L for 33 h. Our patient presented with poor feeding, hypoglycaemia, acidosis and hyperammonaemia (1044 μmol/L at 65 h of age). The patient was treated with intravenous glucose (12 mg/kg per min), insulin, sodium benzoate, sodium phenylbutyrate, carnitine and continuous veno‐venous haemofiltration (CVVH). In spite of these measures, the plasma ammonia concentration remained above 950 μmol/L. After 30 h of CVVH, N‐carbamylglutamate (250 mg/kg) was given through a nasogastric tube. Over the following 4 h, the plasma ammonia fell from 1410 μmol/L to 267 μmol/L. Despite stopping CVVH, the ammonia level dropped to 137 μmol/L over the next 2 h and it continued to fall while the intravenous drug doses were reduced. The patient was readmitted, aged 4 weeks, with hyperammonaemia (347 μmol/L) and again this responded to N‐carbamylglutamate. In contrast, we report a previous patient with propionic acidaemia who showed no response to a lower dose of N‐carbamylglutamate (25 mg/kg).
Interaction between anxiety, depression, quality of life and clinical parameters in chronic tension‐type headache
Authors: Peñacoba‐Puente Cecilia , Fernández‐de‐las‐Peñas César , González‐Gutierrez Jose L. , Miangolarra‐Page Juan C. , Pareja Juan A.
Published: March 2008

Our aim was to investigate the mediating or moderating role of anxiety and depression in the relationship between headache clinical parameters and quality of life in Chronic Tension‐Type Headache (CTTH). Twenty‐five patients diagnosed with CTTH according to the criteria of the International Headache Society were studied. A headache diary was kept for 4 weeks in order to substantiate the diagnosis and record the pain history. Quality of life was assessed by means of the Medical Outcome Study (MOS) 36‐Item Short‐Form (SF‐36) questionnaire. The Beck Depression Inventory (BDI‐II) was used to assess depression, and the Trait Anxiety Scale (TA) from the State‐Trait Anxiety Inventory was administered in order to assess anxiety. Moderating and mediating analyses were conducted with ordinary least squares multiple regression analysis using the SPSS General Linear Model procedure. Anxiety mediated the effect between headache frequency and quality of life, but not the effect of either headache intensity or duration. Anxiety totally mediated the effects of headache frequency on vitality, social functioning and mental health. On the other hand, depression modulated the effect in the mental health domain. The effect in the mental health domain was a function of the interaction between headache duration and depression (β=−0.34, p<0.05), after controlling for age, gender, the main effects of headache duration, and depression. We did not find anxiety to be a moderating factor between intensity, frequency or duration of headache and perceived quality of life. Anxiety exerts a mediating effect, conditioning the relationship between headache frequency and some quality of life domains; depression seems to play an inherent role in the reduced quality of life of these patients, that is, it has a moderating effect.
Slow regolith degradation without creep determined by cosmogenic nuclide measurements in Arena Valley, Antarctica
Authors: Putkonen Jaakko , Balco Greg , Morgan Daniel
Published: March 2008

Estimates of regolith degradation in the McMurdo Dry Valleys of Antarctica are currently based on indirect evidence and ancient ashes at or near the soil surface that suggest excellent preservation of surfaces. On the other hand, the existing cosmogenic-nuclide surface exposure ages from many parts of the Dry Valleys are younger than the age of surface deposits inferred from stratigraphic relations. This suggests some combination of surface erosion or past ice cover, both of which would reduce the apparent exposure age. This paper quantifies the regolith degradation and/or past ice cover by measuring10Be and26Al from a landslide deposit that contains 11.3 Ma volcanic ash. The surface sample yields an apparent exposure age of only 0.4 Ma. However, measurements of the subsurface nuclide concentrations show that the deposit has not been shielded by ice, and that the age of the ash does not conflict with the apparent exposure age when slow degradation of the deposit (2 m Ma−1) is taken into account. Soil creep, which is a common degradational process in a wide variety of environments, is non-existent at this field site, which likely reflects the persistent lack of bio- and cryoturbation.
CHARACTERIZATIONS OF HYPERSURFACES OF TYPE A2 IN A COMPLEX PROJECTIVE SPACE
Authors: MAEDA SADAHIRO , ADACHI TOSHIAKI
Published: March 2008

In this paper, we characterize hypersurfaces of type A2 in a complex projective space in terms of their geodesics.
The boundary of hyperbolicity for Hénon-like families
Authors: CAO YONGLUO , LUZZATTO STEFANO , RIOS ISABEL
Published: March 2008

We consider C2 Hénon-like families of diffeomorphisms of $ \mathbb R^{2} $ and study the boundary of the region of parameter values for which the non-wandering set is uniformly hyperbolic. Assuming sufficient dissipativity, we show that the loss of hyperbolicity is caused by a first homoclinic or heteroclinic tangency and that uniform hyperbolicity estimates hold uniformly in the parameter up to the bifurcation parameter and even, to some extent, at the bifurcation parameter.
CONSIDERING CAPITALISM IN AMERICAN SOCIAL THOUGHT
Authors: PITTENGER MARK
Published: March 2008

Triumphant capitalism seems nowadays to be a fact of nature, requiring no name and admitting, as Margaret Thatcher famously put it, of “no alternative.” Neither American Capitalism nor Transcending Capitalism shrinks from “naming the system,” as perplexed New Leftists once struggled to do when trying to articulate their own alternative. But having named it, neither book takes as its primary task to define or fully describe that economic and sociocultural system. Rather, both are concerned principally with how twentieth-century American intellectuals, broadly construed, oriented and addressed themselves to the idea of capitalism in light of their respective historical moments’ shifting economic and social realities. Some reformist thinkers came to deny the efficacy of “capitalism” for describing a political–economic order which they believed to be rapidly passing away; their rivals to the right, meanwhile, mounted a reinvigorated defense of the term and its classical implications. While Daniel Bell announced in his 1960 essay on “The End of Ideology in the West” that post-World War II intellectuals had achieved a “rough consensus” on the desirability of the welfare state and political pluralism, the essays in American Capitalism suggest a more complicated picture. The “age of consensus,” that favorite punching bag of recent historians of the United States, takes a few more ritual knocks in the Lichtenstein volume. But the book's essays, in conjunction with Howard Brick's monograph, do establish that the lively discourse on the future of American society which proceeded in the aftermath of World War II was also part of a continuous debate that ran across most of the century's course. Bell suggested one theme of that debate when he argued that Western intellectuals must turn their attention away from political economy in order to address “the stultifying aspects of contemporary culture,” which could not be adequately framed in traditional right-versus-left terms. If Bell's generation, along with the younger New Left thinkers who were soon to appear, found the contradictions of capitalism to be decreasingly pressing, they would find sufficient challenge when they engaged instead with the knotty social and cultural issues of modern America.
Advancing Biocatalysis through Enzyme, Cellular, and Platform Engineering
Authors: Cirino Patrick C. , Sun Lianhong
Published: March 2008

Biocatalysis offers opportunities for highly selective chemical reactions with high turnover rates under relatively mild conditions. Use of whole‐cell or multi‐enzyme systems enables transformations of complexity unmatched by nonbiological routes. However, advantages of biocatalysis are frequently compromised by poor enzymatic performance under non‐native reaction conditions, the absence of enzymes with desired substrate or reaction specificities, and low metabolic fluxes or competing pathways. During the 234th National Meeting of the American Chemical Society, these issues were addressed in the “Advances in Biocatalysis” sessions. Protein engineering and metabolic pathway engineering were used to develop efficient enzymes and whole‐cell catalysts. Novel strategies for the use of enzymes at solid interfaces and in nonaqueous environments were discussed, and efficient biotransformation platforms were demonstrated. These advances broaden the applications of biocatalysis in biofuels, pharmaceuticals, fine chemicals, and human health.
Liposomal Encapsulation of Yeast Alcohol Dehydrogenase with Cofactor for Stabilization of the Enzyme Structure and Activity
Authors: Yoshimoto Makoto , Sato Mami , Yoshimoto Noriko , Nakao Katsumi
Published: March 2008

Yeast alcohol dehydrogenase (YADH) with its cofactor nicotinamide adenine dinucleotide (NAD+) could be stably encapsulated in liposomes composed of POPC (1‐palmitoyl‐2‐oleoyl‐ sn‐glycero‐3‐ phosphocholine). The YADH‐ and NAD+‐containing liposomes (YADH‐NADL) were 100 nm in mean diameter. The liposomal YADH and NAD+ concentrations were 2.3 mg/mL and 3.9 mM, respectively. A synergistic effect of the liposomal encapsulation and the presence of NAD+ was examined on the thermal stability of YADH at 45 and 50 °C. The enzyme stability of the YADH‐NADL was compared to the stabilities of the liposomal YADH (YADHL) containing 3.3 mg/mL YADH without NAD+ as well as the free YADH with and without NAD+. Free YADH was increasingly deactivated during its incubation at 45 °C for 2 h with decrease of the enzyme concentration from 3.3 to 0.01 mg/mL because of the dissociation of tetrameric YADH into its subunits. At that temperature, the coexistence of free NAD+ at 3.9 mM improved the stability of free YADH at 2.3 mg/mL through forming their thermostable complex, although the stabilization effect of NAD+ was lowered at 50 °C. The turbidity measurements for the above free YADH solution with and without NAD+ revealed that the change in the enzyme tertiary structure was much more pronounced at 50 °C than at 45 °C even in the presence of NAD+. This suggests that YADH was readily deactivated in free solution due to a decrease in the inherent affinity of YADH with NAD+. On the other hand, both liposomal enzyme systems, YADH‐NADL and YADHL, showed stabilities at both 45 and 50 °C much higher than those of the above free enzyme systems, YADH/NAD+ and YADH. These results imply that the liposome membranes stabilized the enzyme tertiary and thus quaternary structures. Furthermore, the enzyme activity of the YADH‐NADL showed a stability higher than that of the YADHL with a more remarkable effect of NAD+ at 50 °C than at 45 °C. This was considered to be because even at 50 °C the stabilization effect of lipid membranes on the tertiary and quaternary structures of the liposomal YADH allowed the enzyme to form its thermostable complex with NAD+ in liposomes.
Loss of solar wind plasma neutrality and affect on surface potentials near the lunar terminator and shadowed polar regions
Authors: Farrell W. M. , Stubbs T. J. , Halekas J. S. , Delory G. T. , Collier M. R. , Vondrak R. R. , Lin R. P.
Published: March 2008

As the solar wind is absorbed on the lunar dayside, a clear and obvious plasma void is created in the anti‐solar direction that extends many lunar radii behind the Moon. Plasma adjacent to this void will expand into the depleted region and this process is modeled here using a particle‐in‐cell code. It is found that thermal electrons will diffuse into the void ahead of the ions, creating a break in plasma quasi‐neutrality. In essence, immediately trailing behind the lunar terminator/polar regions, there is a magnetic‐field aligned E‐field peaking near 400 mV/m associated with a standing double‐layer, this layer consisting of fast thermal electrons (electron cloud) moving into the central void ahead of an ion‐enhanced layer. We demonstrate that the surface locations that are incident with the electron cloud (just nightside of the terminator) will develop enhanced negative surface potentials due to the dominance of electron currents. Such regions of large negative potentials near the lunar poles are of interest, especially given NASA's recent announcement of a lunar outpost at the south polar Aitken Basin.
Using aircraft measurements to estimate the magnitude and uncertainty of the shortwave direct radiative forcing of southern African biomass burning aerosol
Authors: Magi Brian I. , Fu Qiang , Redemann Jens , Schmid Beat
Published: March 2008

We estimate the shortwave, diurnally averaged direct radiative forcing (RF) in cloud‐free conditions of the biomass burning aerosol characterized by measurements made from the University of Washington (UW) research aircraft during the Southern African Regional Science Initiative in August and September 2000 (SAFARI‐2000). We describe the methodology used to arrive at the best estimates of the measurement‐based RF and discuss the confidence intervals of the estimates of RF that arise from uncertainties in measurements and assumptions necessary to describe the aerosol optical properties. We apply the methodology to the UW aircraft vertical profiles and estimate that the top of the atmosphere RF (RFtoa) ranges from −1.5 ± 3.2 to −14.4 ± 3.5 W m−2, while the surface RF (RFsfc) ranges from −10.5 ± 2.4 to −81.3 ± 7.5 W m−2. These estimates imply that the aerosol RF of the atmosphere (RFatm) ranges from 5.0 ± 2.3 to 73.3 ± 11.0 W m−2. We compare some of our estimates to RF estimated using Aerosol Robotic Network (AERONET) aerosol optical properties and show that the agreement is good for RFtoa, but poor for RFsfc. We also show that linear models accurately describe the relationship of RF with the aerosol optical depth at a wavelength of 550 nm (τ550). This relationship is known as the radiative forcing efficiency (RFE) and we find that RFtoa (unlike RFatm and RFsfc) depends not only on variations in τ550, but that the linear model itself is dependent on the magnitude of τ550. We then apply the models for RFE to daily τ550 derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite to estimate the RF over southern Africa from March 2000 to December 2006. Using the combination of UW and MODIS data, we find that the annual RFtoa, RFatm, and RFsfc over the region is −4.7 ± 2.7 W m−2, 11.4 ± 5.7 W m−2, and −18.3 ± 5.8 W m−2, respectively.
Variability in carbon stable isotope ratio of heterotrophic respiration in a deciduous needle‐leaf forest
Authors: Takahashi Yoshiyuki , Liang Naishen , Hirata Ryuichi , Machida Toshinobu , Fujinuma Yasumi
Published: March 2008

We investigated spatial and temporal variability in the carbon stable isotope ratio (δ13C) of soil heterotrophic respiration in a deciduous needle‐leaf forest in Japan for 3 years. We used high‐precision isotope measurement coupled with a sampling system optimized for soil respiration to capture this variability under natural conditions. The limitations of chamber‐based measurements combined with spatial variation created a representation error that prevented precise estimates of flux‐weighted mean δ13C, but we could nonetheless characterize the δ13C variations intrinsic to heterotrophic respiration. In the absence of root respiration, δ13C exhibited significant seasonal variation, with a greater range than in previous models. In a root‐exclusion plot, δ13C was lowest at high temperatures but showed a different seasonal course from that of CO2 efflux. A simple model explained the seasonal variation in δ13C using interpool differences in δ13C of decomposed organic matter, in the temperature dependence of decomposition rates, and in the seasonal changes in pool size. The characteristic seasonality of δ13C appears to be associated with the properties of the forest, including litterfall patterns.
Age model and core‐seismic integration for the Cenozoic Arctic Coring Expedition sediments from the Lomonosov Ridge
Authors: Backman Jan , Jakobsson Martin , Frank Martin , Sangiorgi Francesca , Brinkhuis Henk , Stickley Catherine , O'Regan Matthew , Løvlie Reidar , Pälike Heiko , Spofforth David , Gattacecca Jérôme , Moran Kate , King John , Heil Chip
Published: March 2008

Cenozoic biostratigraphic, cosmogenic isotope, magnetostratigraphic, and cyclostratigraphic data derived from Integrated Ocean Drilling Program Expedition 302, the Arctic Coring Expedition (ACEX), are merged into a coherent age model. This age model has low resolution because of poor core recovery, limited availability of biostratigraphic information, and the complex nature of the magnetostratigraphic record. One 2.2 Ma long hiatus occurs in the late Miocene; another spans 26 Ma (18.2–44.4 Ma). The average sedimentation rate in the recovered Cenozoic sediments is about 15 m/Ma. Core‐seismic correlation links the ACEX sediments to the reflection seismic stratigraphy of line AWI‐91090, on which the ACEX sites were drilled. This seismostratigraphy can be correlated over wide geographic areas in the central Arctic Ocean, implying that the ACEX age model can be extended well beyond the drill sites.
Radiogenic isotope record of Arctic Ocean circulation and weathering inputs of the past 15 million years
Authors: Haley B. A. , Frank M. , Spielhagen R. F. , Fietzke J.
Published: March 2008

Lead (Pb), neodymium (Nd), and strontium (Sr) isotopic analyses were carried out on sediment leachates (reflecting the isotope composition of past seawater) and digests of the bulk residues (reflecting detrital continental inputs) of Integrated Ocean Drilling Program (IODP) Leg 302 and core PS2185 from the Lomonosov Ridge (Arctic Ocean). Our records are interpreted to reflect changes in continental erosion and oceanic circulation, driven predominantly by tectonic forcing on million‐year timescales in the older (pre‐2 Ma) part of the record and by climatic forcing of weathering and erosion of the Eurasian continental margin on thousand‐year timescales in the younger (post‐2 Ma) part. These data, covering the past ∼15 Ma, show that continental inputs to the central Arctic Ocean have been more closely linked to glacial and hydrological processes occurring on the Eurasian margin than on continental North America and Greenland. The constancy of the detrital input signatures supports the early existence of an Arctic sea ice cover, whereas the major initiation of Northern Hemisphere glaciation at 2.7 Ma appears to have had little impact on the weathering regime of the Eurasian continental margin.
Rain‐induced effects on the envelope probability density functions in multipath channels
Authors: Gong Shuhong , Huang Jiying , Zhao Xiaolong
Published: March 2008

The fluctuant peculiarities of a signal passing through rain area are studied with the theory of waves propagating through random media. The characteristics of the probability density distribution of a received envelope in rain region are calculated and discussed. The fluctuant rules of a signal in rain region are found. The effects induced by raindrops scattering on the envelope probability density functions (PDFs) in multipath channels are studied using the results in the work by Durgin et al. (2004, 2002). The detailed formulae are derived for one‐path channel and two‐path channel. The envelope PDFs are calculated for a narrowband signal with a given carrier frequency at the condition of a certain rain rate and a certain propagating distance, which are contrasted with those calculated at unfluctuant condition. The general results of the effects induced by raindrops scattering on the envelope PDFs in multipath channels are found. The methods evaluating the effects on Rayleigh fading distribution model and Rician fading distribution model induced by raindrops scattering are discussed. The general methods for studying the impacts of meteorological scattering environment (snow, dust storm for example) on the envelope PDFs in multipath channels are searched.
Automated shock detection and analysis algorithm for space weather application
Authors: Vorotnikov Vasiliy S. , Smith Charles W. , Hu Qiang , Szabo Adam , Skoug Ruth M. , Cohen Christina M. S.
Published: March 2008

Space weather applications have grown steadily as real‐time data have become increasingly available. Numerous industrial applications have arisen with safeguarding of the power distribution grids being a particular interest. NASA uses short‐term and long‐term space weather predictions in its launch facilities. Researchers studying ionospheric, auroral, and magnetospheric disturbances use real‐time space weather services to determine launch times. Commercial airlines, communication companies, and the military use space weather measurements to manage their resources and activities. As the effects of solar transients upon the Earth's environment and society grow with the increasing complexity of technology, better tools are needed to monitor and evaluate the characteristics of the incoming disturbances. A need is for automated shock detection and analysis methods that are applicable to in situ measurements upstream of the Earth. Such tools can provide advance warning of approaching disturbances that have significant space weather impacts. Knowledge of the shock strength and speed can also provide insight into the nature of the approaching solar transient prior to arrival at the magnetopause. We report on efforts to develop a tool that can find and analyze shocks in interplanetary plasma data without operator intervention. This method will run with sufficient speed to be a practical space weather tool providing useful shock information within 1 min of having the necessary data to ground. The ability to run without human intervention frees space weather operators to perform other vital services. We describe ways of handling upstream data that minimize the frequency of false positive alerts while providing the most complete description of approaching disturbances that is reasonably possible.
Killeen Selected as NSF Geosciences Director
Authors: Showstack Randy
Published: March 2008

AGU President Tim Killeen will become assistant director for the geosciences at the U.S. National Science Foundation (NSF) on 1 July 2008, NSF announced on 26 February. At NSF, Killeen will direct the foundation's programs in atmospheric, Earth, and ocean sciences and will oversee a directorate that has a $752 million budget for fiscal year 2008. Killeen's 3‐year appointment, which is an Intergovernmental Personnel Act (IPA) assignment that could be extended, begins 1 day after his term as AGU president ends; on 1 July he becomes AGU past president.

“I feel a call to national service,” Killeen told Eos. It is “a very important time in history when the work we do in the geosciences is not only intellectually exciting and important, but it is pivotal to how we think about the planet, its resources, the environment, our place in space, and everything else.” He also emphasized the importance of increasing the understanding of the Earth and space system and using that knowledge to better human life.