bluuebunny/crossref_metadata_2025 huggingface dataset:
Arsenic K‐edge X‐ray absorption spectroscopy of arsenic in seafood
Authors: George Graham N. , Prince Roger C. , Singh Satya P. , Pickering Ingrid J.
Published: December 2008

It is well known that seafood contains high levels of arsenic. For marine animals arsenic is predominantly present as arsenobetaine and related compounds which are not metabolized and are thought to present no toxic hazard to humans. With edible seaweeds, arsenic is present in different forms, of which arsenosugars are the best known. These species may be metabolized by mammals, and the high arsenic contents of these materials represent a significant environmental source for human exposure to arsenicals in some populations. In this work, we explore the utility of As K‐edge X‐ray absorption near‐edge spectroscopy as an in situ probe of the chemical forms of arsenic in seaweeds. We find that three different chemical types of arsenic are present, consistent with arsenate, an arsenosugar or tetra‐alkyl‐arsonium species, and a trivalent arsenic species.
A Discussion of Noise in Dynamic Light Scattering for Particle Sizing
Authors: Yang Hui , Zheng Gang , Li Meng‐chao
Published: December 2008

In order to acquire high quality measurement data from DLS (Dynamic Light Scattering) experiments, serious attention has to be paid to minimizing the noise involved. In this paper, the noise in DLS for particle sizing is addressed for four parts of the measurement system. The first is the noise caused from the low quality of sample preparation and the scattering medium containing too high or too low concentration of analyte. The second is from the view of optics, i.e., the laser must have sufficient power, be stable under all expected conditions, and usually be restricted to a single transverse mode, in case it causes distortion in measurement data. In addition, if the energy of the incident light is too high, strong absorption occurs, which will induce thermal blooming. The optical components must be carefully chosen and designed to minimize noise from the unit itself. The detection area should be calculated to reach the best signal‐to‐noise ratio and an entrance lens with magnification that is too high and that causes distortion in the ACF (Auto Correlation Function) should be avoided. Some new components such as fiber optics and graded‐index may also introduce new noise. The third factor is the photodetector, which must have adequate speed and sensitivity and possess suitably low internal correlations and noise. In addition, the quantum noise from the detector should be subtracted. The fourth factor is that the correlator should be chosen carefully. In some cases, equipment with a higher speed and more channels should be chosen to minimize the statistical noise.
Prediction of electronic, structural and elastic properties of the hardest oxide: TiO2
Authors: Caravaca M. A. , Casali R. A. , Miño J. C.
Published: December 2008

This work combines the theory of elasticity with first principles quantum mechanic calculations to predict the electronic, structural and elastic properties: elastic constants, bulk moduli of the TiO2 (Titania) in the Pnma phase. Band‐structure shows a direct gap in Γ which increases its value under hydrostatic pressure. It has two regimes: in the range 0–50 GPa the band‐gap has a negative second pressure derivative and changes its sign in the range 50–100 GPa. The band gap becomes indirect at pressures above 150 GPa. This phase improves its mechanical stability and insulator properties under extreme conditions of hydrostatic pressures. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hybrid reflections in InGaP/GaAs(001) by synchrotron radiation multiple diffraction
Authors: de Menezes Alan S. , dos Santos Adenilson O. , Almeida Juliana M. A. , Bortoleto José R. R. , Cotta Mônica A. , Morelhão Sérgio L. , Cardoso Lisandro P.
Published: December 2008

Hybrid reflections (HRs) involving substrate and layer planes (SL type) [Morelhão et al., Appl. Phys. Lett. 73 (15), 2194 (1998)] observed in Chemical Beam Epitaxy (CBE) grown InGaP/GaAs(001) structures were used as a three‐dimensional probe to analyze structural properties of epitaxial layers. A set of (002) rocking curves (ω ‐scan) measured for each 15° in the azimuthal plane was arranged in a pole diagram in ϕ for two samples with different layer thicknesses (#A – 58 nm and #B – 370 nm) and this allowed us to infer the azimuthal epilayer homogeneity in both samples. Also, it was shown the occurrence of (1$ \bar 1 $3) HR detected even in the thinner layer sample. Mappings of the HR diffraction condition (ω:ϕ) allowed to observe the crystal truncation rod through the elongation of HR shape along the substrate secondary reflection streak which can indicate in‐plane match of layer/ substrate lattice parameters. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of long‐term exposure to elevated CO2 conditions in slow‐growing plants using a 12C‐enriched CO2‐labelling technique
Authors: Pardo Antoni , Aranjuelo Iker , Biel Carmen , Savé Robert , Azcón‐Bieto Joaquim , Nogués Salvador
Published: December 2008

Despite their relevancy, long‐term studies analyzing elevated CO2 effect in plant production and carbon (C) management on slow‐growing plants are scarce. A special chamber was designed to perform whole‐plant above‐ground gas‐exchange measurements in two slow‐growing plants (Chamaerops humilis and Cycas revoluta) exposed to ambient (ca. 400 µmol mol−1) and elevated (ca. 800 µmol mol−1) CO2 conditions over a long‐term period (20 months). The ambient isotopic 13C/12C composition (δ13C) of plants exposed to elevated CO2 conditions was modified (from ca. −12.8‰ to ca. −19.2‰) in order to study carbon allocation in leaf, shoot and root tissues. Elevated CO2 increased plant growth by ca. 45% and 60% in Chamaerops and Cycas, respectively. The whole‐plant above‐ground gas‐exchange determinations revealed that, in the case of Chamaerops, elevated CO2 decreased the photosynthetic activity (determined on leaf area basis) as a consequence of the limited ability to increase C sink strength. On the other hand, the larger C sink strength (reflected by their larger CO2 stimulatory effect on dry mass) in Cycas plants exposed to elevated CO2 enabled the enhancement of their photosynthetic capacity. The δ13C values determined in the different plant tissues (leaf, shoot and root) suggest that Cycas plants grown under elevated CO2 had a larger ability to export the excess leaf C, probably to the main root. The results obtained highlighted the different C management strategies of both plants and offered relevant information about the potential response of two slow‐growing plants under global climate change conditions. Copyright © 2008 John Wiley & Sons, Ltd.
Micro‐ and Nanoprinting into Solids Using Reaction‐Diffusion Etching and Hydrogel Stamps
Authors: Grzybowski Bartosz A. , Bishop Kyle J. M.
Published: December 2008

Micropatterned hydrogel stamps soaked in appropriate chemical etchants can imprint various types of micro‐ and nanoarchitectures into metals, conductive oxides, semiconductors, glasses, and crystals. Localized etching is mediated by a reaction‐diffusion process initiated from the stamp microfeatures and gives lateral resolution down to approximately 300 nm. The method is well suited for the rapid prototyping of small‐scale devices including multilevel microfluidic systems and curvilinear optical elements.
Analysis of Linear Alkylbenzene Sulfonate in Waste Water and Sludge by High Performance Liquid Chromatography: An Exercise of Validation
Authors: Bengoechea C. , Cantarero A. Samuel
Published: December 2008

Linear alkylbenzene sulfonate (LAS) an ingredient of many household and industrial detergents can reach the environment after disposal of raw sewage. Its correct detection and quantification in different environmental samples is a critical issue for evaluating its environmental fate. This paper outlines a validation of an entire analytical procedure of LAS in environmental samples, including extraction, pre‐concentration and HPLC detection and quantification with fluorescence detection.
Soya protein reverses dyslipidaemia and the altered capacity of insulin-stimulated glucose utilization in the skeletal muscle of sucrose-rich diet-fed rats
Authors: Oliva María E. , Chicco Adriana G. , Lombardo Yolanda B.
Published: December 2008

The present study investigates the benefits of dietary intake of soya protein upon dyslipidaemia and insulin resistance in rats chronically (8 months) fed a sucrose-rich (63 %) diet (SRD). For this purpose, we analysed the effectiveness of soya protein isolate in improving or reversing these metabolic abnormalities. Wistar rats were fed a SRD for 4 months. By the end of this period, stable dyslipidaemia and insulin resistance were present in the animals. From months 4 to 8, half the animals continued with the SRD and the other half were fed a SRD in which the source of protein casein was substituted by soya. The control group received a diet in which the source of carbohydrate was maize starch. The results showed that: (1) soya protein normalized plasma TAG, cholesterol and NEFA levels in the SRD-fed rats. Moreover, the addition of soya protein reversed the hepatic steatosis. (2) Glucose homeostasis was normalized without changes in circulating insulin levels. Whole-body peripheral insulin sensitivity substantially improved. Besides, soya protein moderately decreases body weight gain limiting the accretion of visceral fat. (3) By shifting the source of dietary protein from casein to soya during the last 4 months of the feeding period it was possible to reverse both the diminished insulin-stimulated glucose oxidation and disposal in the skeletal muscle of SRD-fed rats. This study provides new data showing the beneficial effect of soya protein upon lipid and glucose homeostasis in the experimental model of dyslipidaemia and insulin resistance.
Role of sulfur amino acids in controlling nutrient metabolism and cell functions: implications for nutrition
Authors: Tesseraud Sophie , Métayer Coustard Sonia , Collin Anne , Seiliez Iban
Published: December 2008

Protein synthesis is affected when an insufficient level of sulfur amino acids is available. This defect may originate from dietary amino acid deficiency and/or excessive amino acid utilisation for other purposes such as the synthesis of glutathione and acute-phase proteins during catabolic stress. Sulfur amino acids are recognised to exert other significant functions since they are precursors of essential molecules, are involved in the methylation process, participate in the control of oxidative status, and may act as mediators affecting metabolism and cell functions. Despite this increased understanding of the role of sulfur amino acids, many questions still remain unanswered due to the complexity of the mechanisms involved. Moreover, surprising effects of dietary sulfur amino acids have been reported, with the development of disorders in cases of both deficiency and excess. These findings indicate the importance of defining adequate levels of intake and providing a rationale for nutritional advice. The aim of the present review is to provide an overview on the roles of sulfur amino acids as regulators of nutrient metabolism and cell functions, with emphasis placed on the implications for nutrition.
Copper deficiency in rodents alters dopamine β-mono-oxygenase activity, mRNA and protein level
Authors: Nelson Kyle T. , Prohaska Joseph R.
Published: December 2008

Cu is an essential cofactor for at least twelve mammalian enzymes including dopamine β-mono-oxygenase (DBM), which converts dopamine (DA) to noradrenaline (NA). Previous studies reported that certain Cu-deficient (Cu−) rat tissues have lower NA and higher DA than Cu-adequate (Cu+) tissues, suggesting that DBM function was impaired. However,in vitrostudies suggested that DBM activity is higher in Cu− tissue. Experiments were conducted on adrenal glands (AG), medulla oblongata/pons (MO), vas deferens (VD) and heart (HT) from a single rat experiment to provide data to help clarify this puzzling contradiction.In vitroDBM activity assays showed Cu− samples had significantly higher activity than Cu+ samples in both AG and MO, but not VD. Activity data were confirmed by Western immunoblots. Quantitative real-time PCR demonstrated higher DBM mRNA in Cu− tissues but unaltered levels of several other cuproenzymes and Cu-binding proteins. Previous pharmacological data implied that high DBM was associated with low NA. HPLC analyses confirmed that NA and DA levels in Cu− MO, VD and HT were significantly lower and higher, respectively, than in Cu+ tissues. However, the NA content of AG was not statistically lower. Furthermore there was no correlation between higher DBM mRNA and lower NA in four Cu−tissues. Adequate dietary Cu is essential to support DBM functionin vivobut additional studies are needed to determine the mechanism for increased DBM transcription associated with Cu deficiency.
“Read It Also to the Gentiles”: The Displacement and Recasting of the Philosopher in theVita Antonii
Authors: Urbano Arthur
Published: December 2008

In his correspondence with the Corinthian community, the Apostle Paul addressed the problem of factionalism, his criticism aimed particularly against a faction of educated members who regarded their knowledge as evidence of social superiority. He countered these types of claims to superiority by proposing a dichotomy of wisdoms—“the wisdom of this world” and “God's wisdom”:

Yet among the mature we do speak wisdom, though it is not a wisdom of this age or of the rulers of this age, who are doomed to perish. But we speak God's wisdom, secret and hidden, which God decreed before the ages for our glory.
Colonialism, Biblical World-Making, and Temporalities in Olaudah Equiano'sInteresting Narrative
Authors: Johnson Sylvester A.
Published: December 2008

The autobiography of Olaudah Equiano (1745–1797) offers an unusual portrait of the dynamic relationship between scripture and colonialism. In 1789 Equiano, who also went by the name Gustavus Vassa, related his experience of slavery to support abolitionism in Britain in the form of a best-selling, two-volume autobiography titledThe Interesting Narrative of the Life of Olaudah Equiano, or Gustavus Vassa, the African, Written by Himself. Equiano's autobiography comprises a striking description of religion and culture among the Igbo of West Africa, the nation with which he identified by birth. According to Equiano, the Igbo were descended from ancient Jews, and their religion was a modern survival of ancient biblical religion. This claim, seemingly casual at first, is actually a complicated maneuver that reveals how deeply he had mined a trove of biblical commentary to shape his interesting narrative for a skeptical readership. The early modern genre of biblical commentary, which was deeply influenced by the exigencies of European colonialism, constitutes in its own right an authoritative literature that proved quite useful for Equiano.
Evangelical Secularism and the Measure of Leviathan
Authors: Modern John Lardas
Published: December 2008

Statistics point to a “surge” in evangelical publications as well as in the practices of evangelical piety in the first half of the nineteenth century. In order to explain these parallel trends, however, mere measurement falls short in adequately addressing the strange power evangelical media institutions assumed during this period. In 1825, for example, the American Tract Society announced its agenda of “systematic organization,” a directive that applied equally,and simultaneously, to words on the page, to readers on the ground, and to the airy abstractions of the nation-state.
9-O-acetylated sialic acids enhance entry of virulentLeishmania donovanipromastigotes into macrophages
Authors: GHOSHAL A. , MUKHOPADHYAY S. , CHAVA A. K. , GERWIG G. J. , KAMERLING J. P. , CHATTERJEE M. , MANDAL C.
Published: December 2008

Distribution of 9-O-acetylated sialic acids (9-O-AcSA) onLeishmania donovanihas been previously reported. Considering their role in recognition, the differential distribution of sialic acids especially 9-O-acetylated sialic acids in avirulent (UR6) versus virulent (AG83 and GE1) promastigotes ofLeishmania donovaniand its role in entry into macrophages was explored. Fluorimetric-HPLC, fluorimetric determination and ELISA revealed 14-, 8- and 5-fold lower sialic acids in UR6 as compared to AG83. Interestingly, on UR6, flow cytometry indicated lower (α2→6)-linked sialoglycoproteins along with minimal 9-O-acetylated sialoglycoproteins by Scatchard analysis. Further, UR6 demonstrated a 9- and 14·5-fold lower infectivity and phagocytic index than AG83. Additionally, de-O-acetylation and de-sialylation of AG83 demonstrated a 3- and 1·5-fold reduced phagocytic index. The role of 9-O-AcSA in entry was further confirmed by pre-blocking the macrophage surface with a cocktail of sugars followed by microscopic quantification. The phagocytic index of AG83 exclusively through 9-O-AcSA was significantly high. Interestingly, AG83 produced higher metacyclic promastigotes containing increased 9-O-AcSA as compared to avirulent UR6 supporting its virulent nature. Taken together; our results conclusively demonstrate the increased presence of 9-O-acetylated sialic acid on promastigotes of virulentLeishmania donovanias compared to avirulent UR6 and their subsequent role in entry within macrophages.
Antarctic winter scientific stations to the International Polar Year, 2007–2009
Authors: Headland R. K.
Published: December 2008

The earliest winter scientific station established in the Antarctic was in 1883 as part of the first International Polar Year (IPY) programme. Subsequently, to the IPY of 2007–2009, scientific stations have been deployed on 139 sites (103 on the Antarctic continent, 36 on the peri-Antarctic islands), by 24 countries for a cumulative total of 2666 winters to that of 2008. This paper summarises the winter dates, locations, and national status of all stations in the region. It thus includes all winter stations of the three IPYs and those of the International Geophysical Year (1957–1958). The positions of 120 of these winter stations are south of 60°S, the boundary of the Antarctic Treaty of 1959 (although many of them predate the Treaty).
The date of birth of Captain F.R.M. Crozier R.N.
Authors: Campbell R. J.
Published: December 2008

The generally accepted date of birth of F.R.M. Crozier is 17 September 1796. On the basis of a fresh scrutiny of the evidence, it is suggested that 16 August 1796 is more probable.
Chile, the International Geophysical Year, and the Antarctic
Authors: Baker F. W. G.
Published: December 2008

This note draws attention to the fact the formal motion presented at the first International Geophysical Year (IGY) Antarctic Conference, recommending that the aims of the conference were exclusively scientific was proposed by the Chilean delegation.
Analysis of a supra-annual cycle: reproductive phenology of the palmOenocarpus batauain a forest of the Colombian Andes
Authors: Rojas-Robles Rosario , Stiles F. Gary
Published: December 2008

During a 4-y study of the palmOenocarpus bataua, 368 reproductive structures on 102 palms were monitored. A reproductive structure required nearly 2 y for successful completion, from bud to ripe fruit. We found correlations with summed rainfall and averaged relative humidity and/or solar radiation for initiation of bud appearance, flowering and fruit maturation over 0–4 mo prior to the events, and another set of correlations over longer periods up to 11–12 mo before. Climatic variables showing short-term correlations (apparently triggering an event) often differed from those showing long-term correlations (which presumably initiated developmental processes culminating in the event itself). A high degree of asynchrony occurred in production of reproductive structures both within and between individual palms even within major reproductive peaks, and there were pronounced differences between individuals in total reproductive effort. Nearly all palms passed 1–3 y with little or no reproduction despite similar environmental conditions between years. We conclude that the supra-annual cycle of this palm is not the result of inadequate environmental cues in some years. There appear to be at least two different types of supra-annual cycles in tropical plants, differing in the relative importance of extrinsic cues vs. intrinsic physiological rhythms and in intrapopulation synchrony.
Herbaceous monocot plant form and function along a tropical rain-forest light gradient: a reversal of dicot strategy
Authors: Swenson Nathan G.
Published: December 2008

Whole plant form and function vary spectacularly across the seed plants. In recent years, plant evolutionary ecologists have begun to document this diversity on large geographic scales by analysing ‘functional traits’ that are indicative of whole plant performance across environmental gradients (Swenson & Enquist 2007, Wright et al. 2004). Despite the high degree of functional diversity in tropical forests, convergence in function does occur locally along successional or light gradients (Bazzaz & Pickett 1980, Swaine & Whitmore 1988).
Effect of vegetation density on the use of trails by bats in a secondary tropical rain forest
Authors: Caras Tamir , Korine Carmi
Published: December 2008

Natural forests are composed of a heterogeneous mixture of plant architectures that change temporally and spatially. In addition, variation in ridges, tree falls, natural clearing, logs and animal or man-made paths results in a topographic complexity which is likely to have a profound effect on the movements of animals within the forest.
The decline of defined benefit plans and job tenure
Authors: SCHRAGER ALLISON
Published: December 2008

This paper investigates the consequences of relying on assets accumulated in a defined contribution pension plan compared to an annuity based on salary from a defined benefit plan. Although a defined contribution plan varies with asset returns, it may be more desirable than a defined benefit plan when wage variability and job turnover are adequately considered. It is found that both job separation rates and wage variance increased in the 1990s. The new calibrations of these variables are used in a life-cycle model where a worker chooses between a defined benefit and a defined contribution plan. It is shown that the increase in job turnover made defined contribution the dominant pension plan.
Morita equivalences and KK-theory for Banach algebras
Authors: Paravicini Walther
Published: December 2008

Vincent Lafforgue's bivariant K-theory for Banach algebras is invariant in the second variable under a rather general notion of Morita equivalence. In particular, the ordinary topological K-theory for Banach algebras is invariant under Morita equivalences.
Tracing the early development of harmful algal blooms on the West Florida Shelf with the aid of Lagrangian coherent structures
Authors: Olascoaga M. J. , Beron‐Vera F. J. , Brand L. E. , Koçak H.
Published: December 2008

Several theories have been proposed to explain the development of harmful algal blooms (HABs) produced by the toxic dinoflagellate Karenia brevis on the West Florida Shelf. However, because the early stages of HAB development are usually not detected, these theories have been so far very difficult to verify. In this paper we employ simulated Lagrangian coherent structures (LCSs) to trace potential early locations of the development of a HAB in late 2004 before it was transported to a region where it could be detected by satellite imagery. The LCSs, which are extracted from surface ocean currents produced by a data‐assimilative HYCOM (HYbrid‐Coordinate Ocean Model) simulation, constitute material fluid barriers that demarcate potential pathways for HAB evolution. Using a simplified population dynamics model we infer the factors that could possibly lead to the development of the HAB in question. The population dynamics model determines nitrogen in two components, nutrients and phytoplankton, which are assumed to be passively advected by surface ocean currents produced by the above HYCOM simulation. Two nutrient sources are inferred for the HAB whose evolution is found to be strongly tied to the simulated LCSs. These nutrient sources are found to be located nearshore and possibly due to land runoff.
Transparency of the atmosphere to short horizontal wavelength gravity waves
Authors: Preusse Peter , Eckermann Stephen D. , Ern Manfred
Published: December 2008

We use theory and global ray modeling to investigate how the potential of gravity waves to transport momentum flux globally from the lower atmosphere into the mesosphere and lower thermosphere (MLT) varies with horizontal wavelength and ground‐based phase speed. Ray modeling is performed using the Gravity Wave Regional or Global Ray Tracer (GROGRAT) interfaced to realistic three‐dimensional global winds and temperatures from 0 to 100 km altitude, specified by fusing analysis fields at lower altitudes to GCM results higher up. We focus on gravity waves in the short 10‐ to 50‐km horizontal wavelength range that are unresolved by global models and, according to theory, can transport appreciable momentum flux into the MLT. Ray results for different seasons reproduce some of the limits derived from simple wave theory: that horizontal wavelengths shorter than 10 km tend to be removed by vertical reflection or evanescence at the source and slower phase speeds are more prone to critical level removal, leading to a preference for waves with longer horizontal wavelengths and faster ground‐based phase speeds to reach the MLT. These findings are compared to the wavelength scales currently resolved by satellite limb and nadir sounders, highlighting wavelength ranges currently measured and those currently unresolved. A road map is developed for how current and future satellite measurements can be combined to measure the full space‐time spectrum of gravity waves relevant to eddy flux deposition and momentum forcing of the global MLT. In particular, recommendations for new satellite measurement strategies that fill current measurement gaps are provided.
Tidal marshes as disequilibrium landscapes? Lags between morphology and Holocene sea level change
Authors: Kirwan Matthew L. , Murray A. Brad
Published: December 2008

Historical acceleration in the rate of global sea level rise and recent observations of marsh degradation highlight the importance of understanding how marshes respond to sea level change. Here, we use an existing numerical model to demonstrate that marsh morphology, and its effect on biological productivity and vertical accretion, could lag century‐scale sea level rise rate oscillations by several decades. This suggests that marshes, and perhaps other intertidal environments, have not been in equilibrium with Holocene sea level. Additional results suggest that marshes have not yet fully responded to historical sea level acceleration. Consequently, marshes today may be out of equilibrium with modern rates of sea level rise, and further adjustment in the form of platform deepening and channel erosion could be expected. Under an accelerating sea level rise rate, the morphology and productivity of marshland will reflect environmental conditions of the past, and studies of marshes today will underestimate their response to sea level rise.
Estimating weights for the use of time‐dependent gravity recovery and climate experiment data in constraining ocean models
Authors: Quinn Katherine J. , Ponte Rui M.
Published: December 2008

Using Gravity Recovery And Climate Experiment (GRACE) data to constrain ocean general circulation models requires quantitative knowledge of the errors in GRACE‐derived estimates of ocean bottom pressure (pb) change, which for our purposes include not only instrument noise but also variability not represented in the models (e.g., post‐glacial rebound and self‐gravitation effects). We attempt a spatial mapping of these errors by comparing several GRACE data products to pb simulations from an ocean model. Uncertainties in the global ocean mean , partly related to the net freshwater flux into the ocean, and in the regional pb anomalies about that mean are considered separately. The resultant regional error estimates (∼1–3 cm), when zonally averaged, are comparable to the calibrated errors provided by the GRACE processing centers, except for enhanced errors near some continental regions with high seasonal hydrology signals or large mass trends. Errors in the GRACE‐derived values estimated from model‐data differences (∼0.2 cm) are also comparable with those from the calibrated errors. For both pb and estimates, accounting for the effects of geocenter noise is important. Replacing the C20 harmonic term in the GRACE data with estimates derived from satellite laser ranging results in significantly lower errors in the Southern Ocean. We also find lower errors at high latitudes when the variability of the atmospheric pressure over the land is removed from the data. Given the estimated errors and model‐data comparisons, GRACE data should be useful for constraining estimates of , particularly at interannual periods, but less so when considering regional pb variability.
Update on a proposed mechanism for the regulation of minimum midtropospheric and surface temperatures in the Arctic and Antarctic
Authors: Herman B. , Barlage M. , Chase T. N. , Pielke R. A.
Published: December 2008

This paper is an update from our earlier paper to include data through July 2008. In our earlier paper, which included data through 1998, a mechanism which generally limits Arctic minimum 500 mb temperatures to the −40°C to −45°C range was presented. The current paper is in agreement with those earlier findings and also shows some evidence of later autumn onset dates of the initial appearance of these temperatures, in agreement with the recent reduction of Arctic sea ice cover in the summer and fall. In the southern hemisphere, little change can be seen for the seasonal onset and end of the temperatures reaching −40°C area, while the appearance of temperatures reaching −44°C area seems to show a later onset date beginning about 1998, but this time period is too small to define a clear trend. The limiting of the minimum of these midtropospheric temperatures has important implications for minimum surface temperatures that can occur over land during the Arctic winter.
Exploring the stratospheric/tropospheric response to solar forcing
Authors: Rind D. , Lean J. , Lerner J. , Lonergan P. , Leboissitier A.
Published: December 2008

We use the new Goddard Institute for Space Studies Global Climate Middle Atmosphere Model 3 with four different resolutions to investigate various aspects of solar cycle influence on the troposphere/stratosphere system. Three different configurations of sea surface temperatures are used to help determine whether the tropospheric response is due to forcing from above (UV variations impacting the stratosphere) or below (total solar irradiance changes acting through the surface temperature field). The results show that the stratospheric response is highly repeatable and significant. With the more active sun, the annual residual circulation change features relative increased upwelling in the Southern Hemisphere and downwelling in the Northern Hemisphere. Stratospheric west wind increases extend down into the troposphere, especially during Southern Hemisphere winter, and in some runs the jet stream weakens and moves poleward. The predominant tropospheric response consists of warming in the troposphere, with precipitation decreases south of the equator and in the Northern Hemisphere subtropics and midlatitudes, with increases north of the equator especially over southern Asia. The tropospheric response is often not significant, but is fairly robust among the different simulations. These features, which have been reported in observations and other model studies, appear to be driven both from the stratosphere and the surface; nevertheless, they account for only a small percentage of the total variance. More accurate simulations of the solar cycle stratospheric ozone response, the quasi‐biennial oscillation, and coupled atmosphere‐ocean dynamics are necessary before any conclusions can be deemed definitive.
Ecohydrologically important subsurface structures in peatlands revealed by ground‐penetrating radar and complex conductivity surveys
Authors: Kettridge Nicholas , Comas Xavier , Baird Andrew , Slater Lee , Strack Maria , Thompson Dan , Jol Harry , Binley Andrew
Published: December 2008

The surface pattern of vegetation influences the composition and humification of peat laid down during the development of a bog, producing a subsurface hydrological structure that is expected to affect both the rate and pattern of water flow. Subsurface peat structures are routinely derived from the inspection of peat cores. However, logistical limits on the number of cores that can be collected means that the horizontal extent of these structures must be inferred. We consider whether subsurface patterns in peat physical properties can be mapped in detail over large areas with ground‐penetrating radar (GPR) and complex conductivity by comparing geophysical measurements with peat core data along a 36 m transect through different microhabitats at Caribou Bog, Maine. The geophysical methods show promise. Peat horizons produced radar reflections because of changes in the volumetric moisture content. Although these reflections could not be directly correlated with the peat core data, they were related to the depth‐averaged peat properties which varied markedly between the microhabitats. Well‐decomposed peat below a hollow was characterized by a discontinuous sequence of chaotic wavy reflections, while distinct layering of the peat below an area of hummocks coincided with a pattern of parallel planar reflections. The complex conductivity survey showed spatial variation in the real and imaginary conductivities which resulted from changes in the pore water conductivity; peat structures may also have influenced the spatial pattern in the complex conductivity. The GPR and complex conductivity surveys enabled the developmental history of the different microhabitats along the studied transect to be inferred.
The Gloomy Prospect Wins: Statistical Significance and Population Stratification in Genome Wide Association Studies
Authors: Turkheimer Eric
Published: December 2008

This one-hour lecture by Dr. Eric Turkheimer of the University of Virginia's Department of Psychology explored the following:The contemporary era has seen a convergence of genomic technology and traditional social scientific concerns with complex human individual differences. Rather than finally turning social science into a replicable hard-scientific enterprise, genomics has gotten bogged down in the long-standing frustrations of social science. A recent report of an extensive genome wide association study of human height demonstrates the profound difficulties of explaining uncontrolled human variation at a genomic level. The statistical technologies that have been brought to bear on the problem of genomic association are simply modifications of similar methods that have been used by social scientists for decades, with little success. The motivation for the statistical methods in genomics is the same as it is in traditional social science: An attempt to discern linear causation in complex systems when experimental control is not possible.For an audio recording of Dr. Turkheimer's lecture, please visit "http://cirge.stanford.edu/activities/events.html.":http://cirge.stanford.edu/activities/events.html
Inhibitors of apoptosis catch ubiquitin
Authors: Rajalingam Krishnaraj , Dikic Ivan
Published: December 2008

IAP (inhibitor of apoptosis) proteins are a class of anti-apoptotic regulators characterized by the presence of BIR (baculoviral IAP repeat) domains. Some of the IAPs also possess a RING (really interesting new gene) domain with E3 ubiquitin ligase activity. In this issue of the Biochemical Journal, Blankenship et al. unveil the presence of an UBA (ubiquitin-associated domain) in several IAPs. UBAs in c-IAPs (cellular IAPs) bind to monoubiquitin and ubiquitin chains and are implicated in degradation of c-IAPs by promoting their interaction with proteasomes as well as in regulation of TNF-α (tumour necrosis factor-α)-induced apoptosis. These novel observations establish IAPs as ubiquitin-interacting proteins and opens up new lines of investigation.
Selenium status highly regulates selenoprotein mRNA levels for only a subset of the selenoproteins in the selenoproteome
Authors: Sunde Roger A. , Raines Anna M. , Barnes Kimberly M. , Evenson Jacqueline K.
Published: December 2008

Gpx (glutathione peroxidase)-1 enzyme activity and mRNA levels decrease dramatically in Se (selenium) deficiency, whereas other selenoproteins are less affected by Se deficiency. This hierarchy of Se regulation is not understood, but the position of the UGA selenocysteine codon is thought to play a major role in making selenoprotein mRNAs susceptible to nonsense-mediated decay. Thus in the present paper we studied the complete selenoproteome in the mouse to uncover additional selenoprotein mRNAs that are highly regulated by Se status. Mice were fed on Se-deficient, Se-marginal and Se-adequate diets (0, 0.05 and 0.2 μg of Se/g respectively) for 35 days, and selenoprotein mRNA levels in liver and kidney were determined using microarray analysis and quantitative real-time PCR analysis. Se-deficient mice had liver Se concentrations and liver Gpx1 and thioredoxin reductase activities that were 4, 3 and 3% respectively of the levels in Se-adequate mice, indicating that the mice were Se deficient. mRNAs for Selh (selenoprotein H) and Sepw1 (selenoprotein W) as well as Gpx1 were decreased by Se deficiency to <40% of Se-adequate levels. Five and two additional mRNAs were moderately down-regulated in Sedeficient liver and kidney respectively. Importantly, nine selenoprotein mRNAs in liver and fifteen selenoprotein mRNAs in the kidney were not significantly regulated by Se deficiency, clearly demonstrating that Se regulation of selenoprotein mRNAs is not a general phenomenon. The similarity of the response to Se deficiency suggests that there is one underlying mechanism responsible. Importantly, the position of the UGA codon did not predict susceptibility to Se regulation, clearly indicating that additional features are involved in causing selenoprotein mRNAs to be sensitive to Se status.
Liverpool: the early years of biochemistry
Authors: Pitt G.A.J.
Published: December 2008

The first Chair and department of biochemistry in the U.K. were founded at the University of Liverpool in 1902, thanks to a generous donation by William Johnston, a Liverpool shipowner. The first holder of the Johnston Chair, Benjamin Moore, was a dynamic man, who set up an active research centre. In 1906, he and Edward Whitley founded The Bio-Chemical Journal as a private venture, and in 1912, they sold it to the Biochemical Society. Moore also initiated the first Honours School of Biochemistry in the country before moving to London in 1914 and being succeeded by Walter Ramsden. The development of the department was stopped by World War I, and there was little expansion in the 1920s. After Ramsden's retirement in 1931, the third Johnston Professor, Harold Channon, increased staff numbers, ran a successful research school and re-established the Honours course. World War II brought that to an end, and Channon moved into industry. After the war, biochemistry expanded from a niche subject in a small number of British universities into one that was strongly represented in most universities, but the penetration of biochemistry into wide areas of functional biology has blurred conventional subject boundaries, so in many universities (including the University of Liverpool), departments of biochemistry have been incorporated into large more general schools.
Isolation of novel Src substrates
Authors: Courtneidge S.A.
Published: December 2008

We have established and used a method to rapidly isolate tyrosine kinase substrates. The method entails inserting mammalian cDNA libraries into phage vectors. Protein production is induced, then plaque proteins are transferred to nitrocellulose and phosphorylated by the kinase of interest. Proof of principle for this technique was established by the isolation of a number of known Src substrates. We also implicated other known proteins as substrates for Src by this approach, and isolated a number of novel genes. Several of these are indeed Src substrates in mammalian cells. We have characterized further one of these novel substrates, Fish, which is a multi-domain adaptor protein.
Activated M-phase-promoting factor (MPF) is exported from the nucleus of starfish oocytes to increase the sensitivity of the Ins(1,4,5)P3 receptors
Authors: Santella L. , Ercolano E. , Lim D. , Nusco G.A. , Moccia F.
Published: December 2008

Starfish oocytes that are extracted from the ovaries are arrested at the prophase of the first meiotic division. At this stage of maturation, they are characterized by a large nucleus called the germinal vesicle. Meiosis resumption (maturation) can be induced in vitro by adding the hormone 1-methyladenine (1-MA) to the seawater in which the oocytes are suspended. Earlier work in our laboratory had detected Ca2+ increases in both the cytoplasm and the nucleus of the oocytes approx. 2 min after the 1-MA challenge. The nuclear Ca2+ increase was found to be essential for the continuation of the meiotic cycle, since the injection of bis-(o-aminophenoxy)ethane-N,N,N´,N´-tetra-acetic acid (BAPTA) into the nuclear compartment completely blocked the re-initiation of the cell cycle. We have recently confirmed, using confocal microscopy, that the cytoplasmic and nuclear Ca2+ pools are regulated independently and that the nuclear envelope in starfish oocytes is not freely permeated by the Ca2+ wave that sweeps across the nuclear region. Studies by others have shown that the sensitivity of the Ins(1,4,5)P3 (IP3) receptors (IP3Rs) to IP3 increases during oocyte maturation, so that they release progressively more calcium in response to the injection of IP3, as maturation proceeds. We have now shown that the increased sensitivity of the IP3Rs may depend on the activation of the cyclin-dependent kinase, MPF (M-phase-promoting factor) that occurs in the nucleus. MPF does not directly phosphorylate IP3Rs but phosphorylates instead the actin-binding protein actin depolymerization factor (ADF)/cofilin.
Phospholipase D1 and potential targets of its hydrolysis product, phosphatidic acid
Authors: Ktistakis N.T. , Delon C. , Manifava M. , Wood E. , Ganley I. , Sugars J.M.
Published: December 2008

Phospholipase D (PLD) hydrolyses phosphatidylcholine into phosphatidic acid (PA) and choline. Our work aims to understand the properties of PLD1, and to identify downstream targets of PA. In one set of projects, we have focused on membrane-targeting mechanisms and have proposed a hierarchy of signals that allows PLD1 to localize to intracellular membranes. These signals involve a functional pleckstrin homology (PH) domain and its fatty acylation on two adjacent cysteine residues. A nearby Phox homology (PX) domain may modulate the function of the fatty acylated PH domain. This complex array of signals is probably necessitated by the targeting of PLD1 to multiple endocytic and secretory membranes under basal and signal-dependent conditions. In another set of projects, we have used chemically synthesized PA coupled to a solid support in order to identify proteins that interact with this phospholipid. Several proteins have emerged from this screen as potential targets. Some (e.g. ADP-ribosylation factor, coatomer β subunit) are involved in trafficking and their PA affinity can be understood in terms of their regulated cycling on and off membranes during rounds of transport. Others (sphingosine 1-phosphate kinase and PtdIns4P 5-kinase) are implicated in pathways that also involve PLD activation. Others still are novel proteins (brain-specific neurochondrin) whose affinity for PA may contribute to an understanding of their cellular function.
Yersinia pestis and plague
Authors: Titball R.W. , Hill J. , Lawton D.G. , Brown K.A.
Published: December 2008

Yersinia pestis is the aetiological agent of plague, a disease of humans that has potentially devastating consequences. Evidence indicates that Y. pestis evolved from Yersinia pseudotuberculosis, an enteric pathogen that normally causes a relatively mild disease. Although Y. pestis is considered to be an obligate pathogen, the lifestyle of this organism is surprisingly complex. The bacteria are normally transmitted to humans from a flea vector, and Y. pestis has a number of mechanisms which allow survival in the flea. Initially, the bacteria have an intracellular lifestyle in the mammalian host, surviving in macrophages. Later, the bacteria adopt an extracellular lifestyle. These different interactions with different host cell types are regulated by a number of systems, which are not well characterized. The availability of the genome sequence for this pathogen should now allow a systematic dissection of these regulatory systems.
Temporal regulation of outer surface proteins of the Lyme-disease spirochaete Borrelia burgdorferi
Authors: Schwan T.G.
Published: December 2008

In the 20 years since the first agent of Lyme disease was discovered, much interest has focused on the possible biological roles of a few outer surface proteins (Osps) in the alternating life cycle that includes ticks and vertebrate hosts. Two major proteins, OspA and OspC, are differentially regulated by the spirochaete Borrelia burgdorferi during the several days when ticks feed. The reciprocal decrease in OspA with the rapid up-regulation of OspC by the spirochaetes when ticks are feeding suggests that OspA aids in spirochaete attachment while OspC assists in the dissemination of spirochaetes from tick to vertebrate. Future experiments in ticks with mutant spirochaetes that lack these proteins should clarify the speculative functions currently given to these proteins.
Sense of smell: recognition and transduction of olfactory signals
Authors: Breer H.
Published: December 2008

The primary processes in odour perception, i.e. recognition and transduction of olfactory stimuli, are mediated by the chemosensory olfactory neurons. Interaction of odorous compounds with suitable receptor proteins in the membrane of a subset of cells elicits chemo-electrical transduction pathways, including second messenger cascades and ion channels, that modulate the excitability of the sensory neurons, i.e. converting the chemical stimulus into electrical impulses. The encoded information is conveyed via the axons onto distinct glomeruli in the olfactory bulb. Olfactory sensory cells expressing the same receptor type are segregated spatially in a distinct zone of the nasal epithelium and converge their axons to one or a few distinct glomeruli. The emerging chemotopic maps are considered to be crucial for processing and encoding sensory information of olfactory stimuli.
Pheromones, binding proteins and receptor responses in rodents
Authors: Novotny M.V.
Published: December 2008

Their well-developed chemical communication systems make rodents popular in research that aims to understand the connections between genes, hormones and behaviour. Structural identification of several pheromones in mice, rats and hamsters now makes it feasible to employ their synthetic analogues in probing olfactory neurons and in the study of various pheromone–protein interactions in intimate detail.