bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional expression of trypsin fromStreptomyces griseusbyPichia pastoris
Authors: Ling Zhenmin , Ma Tengbo , Li Jianghua , Du Guocheng , Kang Zhen , Chen Jian
Published: July 2012

In the present study, the genes encoding trypsinogen and active trypsin from Streptomyces griseus were both cloned and expressed in the methylotrophic yeast Pichia pastoris with the α-factor secretion signal under the control of the alcohol oxidase promoter. The mature trypsin was successfully accumulated extracellularly in soluble form with a maximum amidase activity of 6.6 U ml−1 (batch cultivation with flask cultivation) or 14.4 U ml−1 (fed-batch cultivation with a 3-l fermentor). In contrast, the recombinant trypsinogen formed inclusion bodies and no activity was detected. Replacement of the trypsin propeptide Ala-Pro-Asn-Pro confirmed that its physiological function was as a repressor of activity. More importantly, our results proved that the propeptide inhibited the activity of trypsinogen after its successful folding.
Influences of river regulation and environmental variables on upland bird assemblages in northern Sweden
Authors: Jonsson Micael , Strasevicius Darius , Malmqvist Björn
Published: July 2012

Most large rivers in Sweden are regulated to produce hydropower. This transformation from free‐flowing rivers to chains of elongate run‐of‐river impoundments has been shown to have consequences for aquatic, riparian and adjacent upland environments, and for the emergence patterns of aquatic insects that are important for terrestrial consumers. In this study, we investigated bird assemblages in upland‐forest environments along seven large rivers (three heavily impounded and four free flowing) in northern Sweden. Bird densities were assessed by point counts in the breeding and post‐breeding seasons. While we observed no significant differences in bird species richness between regulated and free‐flowing rivers, cumulative densities of two feeding groups of birds (those feeding on seeds and/or large insects and those feeding on small insects) were higher along free‐flowing rivers than along regulated rivers in the breeding season, consistent with known differences in aquatic‐insect emergence. Further, ordination analyses showed seasonal shifts in bird assemblage structure, and that these shifts differed between regulated and free‐flowing rivers and between the two feeding groups. However, the variables explaining the most variance (11–28 %) in bird assemblage structure were related to a gradient of agricultural‐to‐forest land use. River regulation contributed to the model in the post‐breeding season, but was of relatively low importance. Nevertheless, the observed contrasting seasonal shifts in upland‐forest bird assemblage structure between regulated and free‐flowing rivers suggest that regulation‐induced modifications of aquatic‐insect emergence and subsequent changes in prey availability to the birds are also important considerations.
Synthesis and Characterization of Glucosamide Surfactant
Authors: Han Fu , Deng Yun‐yun , Wang Peng‐li , Song Jia , Zhou Ya‐wen , Xu Bao‐cai
Published: July 2012

The synthesis and structural analysis of glucosamide surfactants of the general formula CnH2n+1NH(CH2)2NHCO(CHOH)4CH2OH (n= 8, 10, 12) are described, and the surface activity properties of the surfactants are studied.N‐alkylethylenediamines were synthesized by the alkylation of the ethylenediamine with alkyl bromide. The glucosamide surfactants,N‐alkyl‐N′‐glucosylethylenediamine (CnGA), were prepared by amidation of the precursor diamine withd‐gluconic acid δ‐lactone. They were structurally characterized by IR,1H NMR and MS. They reduced the surface tension of water to approximately 26–27 mN m−1at concentration levels of (0.5–1.6) × 10−3mol L−1.
La contraception pour les hommes — une cause perdue ?
Authors: Spencer B.
Published: July 2012

Avant la disponibilité de la contraception hormonale féminine, les hommes des pays d’Europe occidentale, à travers l’utilisation du préservatif et la pratique du coït interrompu, avaient une grande partie de la responsabilité pour la régulation des naissances. En dépit de ce fait, le développement des méthodes hormonales masculines a reçu peu de soutien des divers acteurs qui pourraient favoriser leur arrivée sur le marché et leur distribution : l’industrie pharmaceutique, le corps médical, les bailleurs internationaux de fonds de recherche et les médias. Une déconstruction des représentations et valeurs sous-jacentes, mais rarement explicites, relatives aux rapports du genre nous permet de comprendre pourquoi la contraception hormonale masculine reste coincée dans le marasme qui prévaut depuis plusieurs décennies.
Misdiagnosed: Why Current Health Care Change Is Malpractice
Authors: Schilling Christian
Published: July 2012

Misdiagnosed: Why Current Health Care Change Is Malpractice. Ira E. Williams, MD, Tate Publishing & Enterprises, 2010, 260 pages, softcover
Clinical Issues—August 2012
Authors: Denholm Bonnie
Published: July 2012

This Month

Policies for using multidose liquid medications in the OR

Key words: multidose vials, over‐the‐counter medications, elixirs, cough syrup, shelf life, chemical solutions, liquid medications.

Clarifying the definition of and the practices for compounding sterile solutions

Key words: compounding, compounded sterile preparations, sterile solutions.

Storage of emergency medications

Key words: emergency medications, medication storage.
A Magnetic Approach to Treating Progressive Early‐Onset Scoliosis
Authors: Wick Jane M. , Konze Julie
Published: July 2012

Early‐onset scoliosis presents at birth and up to five years of age. Growing rods are a treatment option when early‐onset scoliosis cannot be controlled by serial casts or braces. The function of a growing rod is to allow a child's spine to continue to grow under controlled conditions until a definitive correction can be made when the patient nears skeletal maturity. This article presents two case reports describing the use of an expandable magnetic growing rod in children with progressive, early‐onset scoliosis. After implantation, caregivers expand the rod nonsurgically using an external magnet to obtain and maintain correction while the child grows. The first case report describes the use of a magnetic growing rod in a patient with a rigid spinal curve and a significant rotational deformity; the second case report describes a patient with a more flexible neuromuscular curve. These were the first two patients to be offered treatment with an expandable rod in North America after the surgeon obtained approval to use the device based on compassionate grounds from the US Food and Drug Administration and institutional review board consent and approval for both surgeries.
Fetal Myelomeningocele Repair: A New Standard of Care
Authors: Scully Susan M. , Mallon Maureen , Kerr Joy C. , Ludzia‐DeAngelis Allison
Published: July 2012

Myelomeningocele, also known as spina bifida, is one of the most common congenital anomalies of the central nervous system and the most common open, prenatally repaired birth defect. The Management of Myelomeningocele Study (MOMS), which compared the results of prenatal and postnatal myelomeningocele repair, found prenatal surgery to be much more effective than postnatal surgery. During surgery, the surgeon makes a hysterotomy and repairs the fetal myelomeningocele without removing the fetus from the uterus. After the repair is completed, the surgeon closes the uterus. The obstetric team monitors the mother closely with a goal of performing a cesarean delivery at 37 weeks' gestation. The fetal surgery nursing team used innovative simulation teaching methods to establish and maintain fetal surgery team member competence, resulting in a successful program with good outcomes.
Reaction specificities of the ε‐ionone‐forming lycopene cyclase from rice (Oryza sativa) elucidated in vitro
Authors: Yu Qiuju , Beyer Peter
Published: July 2012

Lycopene cyclases responsible for the formation of ε‐ionone rings (LCYe) mark a plant‐specific bifurcation of carotenogenesis. We investigated purified rice LCYe (OsLCYe) in a liposome‐based biphasic assay system. OsLCYe depends on reduced flavin cofactors stabilizing a transient state formed during the non‐redox cyclization reaction. In contrast to OsLCYb, OsLCYe produces predominantly monocyclic products and monocyclic carotene intermediates are not suitable substrates. Determination of the OsLCYe reaction specificities and the combined use of OsLCYb allow the characterization of the reaction sequence leading to heterocyclic carotenoids. It was also found that 5‐cis‐lycopene, which was thought to be decisive for ε‐cyclization, was not involved in the reaction, with OsLCYe acting as an exclusion filter for this naturally occurring isomer.
Genotoxic stress modulates CDC25C phosphatase alternative splicing in human breast cancer cell lines
Authors: Albert Hélène , Battaglia Eric , Monteiro Carolino , Bagrel Denyse
Published: July 2012

CDC25 (cell division cycle 25) phosphatases are essential for cell cycle control under normal conditions and in response to DNA damage. They are represented by three isoforms, CDC25A, B and C, each of them being submitted to an alternative splicing mechanism. Alternative splicing of many genes is affected in response to genotoxic stress, but the impact of such a stress on CDC25 splicing has never been investigated. In this study, we demonstrate that genotoxic agents (doxorubicin, camptothecin, etoposide and cisplatin), alter the balance between CDC25C splice variants in human breast cancer cell lines both at the mRNA and protein levels. This modulation occurs during the response to moderate, sub‐lethal DNA damage. Our results also suggest that the CDC25C splice variants expression shift induced by a genotoxic stress is dependent on the ATM/ATR signaling but not on p53. This study highlights the modulation of CDC25C alternative splicing as an additional regulatory event involved in cellular response to DNA damage in breast cancer cells.
Mid-Holocene mangrove succession and its response to sea-level change in the upper Mekong River delta, Cambodia
Authors: Li Zhen , Saito Yoshiki , Mao Limi , Tamura Toru , Li Zhen , Song Bing , Zhang Yulan , Lu Anqing , Sieng Sotham , Li Jie
Published: July 2012

Middle Holocene vegetation and mangrove successions are clearly evident in the palynological records of two cores from the upper Mekong River delta in Cambodia. Spanning from ~ 9.4 to 6.3 cal ka BP, the cores mainly record a transgressive sequence from floodplain freshwater marsh to tidal flat, which was overlain by mangrove. Corresponding to the decelerated sea-level rise at ~ 8.3 cal ka BP, pioneer mangrove species Sonneratia alba and Sonneratia caseolaris appeared in the sediments, and then was replaced by regressive mangrove succession containing upward-increasing abundances of Rhizophora apiculata and Bruguiera spp. High salinity- and flooding-tolerant community S. alba was developed at the western core site PSG at ~ 8.2 cal ka BP, and the eastern core site PK at ~ 7.5 cal ka BP. The time difference of S. alba appearance between the two sites might be resulted from the complexity of sedimentary environment, where a higher sediment supply was provided to the western floodplain than to the eastern floodplain. After 7.5 cal ka BP, aggradational stacking of intertidal sediments, of which the thickness is larger than the present maximum tidal range, may have resulted from continuous sea-level rise during 7.5–7.0 cal ka BP.
Radiative instability of an anticyclonic vortex in a stratified rotating fluid
Authors: Park Junho , Billant Paul
Published: July 2012

In strongly stratified fluids, an axisymmetric vertical columnar vortex is unstable because of a spontaneous radiation of internal waves. The growth rate of this radiative instability is strongly reduced in the presence of a cyclonic background rotation $f/ 2$ and is smaller than the growth rate of the centrifugal instability for anticyclonic rotation, so it is generally expected to affect vortices in geophysical flows only if the Rossby number $Ro= 2\Omega / f$ is large (where $\Omega $ is the angular velocity of the vortex). However, we show here that an anticyclonic Rankine vortex with low Rossby number in the range $\ensuremath{-} 1\leq Ro\lt 0$, which is centrifugally stable, is unstable to the radiative instability when the azimuthal wavenumber $\vert m\vert $ is larger than 2. Its growth rate for $Ro= \ensuremath{-} 1$ is comparable to the values reported in non-rotating stratified fluids. In the case of continuous vortex profiles, this new radiative instability is shown to occur if the potential vorticity of the base flow has a sufficiently steep radial profile. The most unstable azimuthal wavenumber is inversely proportional to the steepness of the vorticity jump. The properties and mechanism of the instability are explained by asymptotic analyses for large wavenumbers.
Simulating the Two Views of the British Industrial Revolution
Authors: Harley C. Knick , Crafts N.F.R.
Published: July 2012

This study examines technical change, trade, economic structure, and growth during the British Industrial Revolution by means of computational general equilibrium (CGE) modeling. It rejects Peter Temin's contention that our “new view” of sectorally concentrated productivity growth is inconsistent with industrial export data. A CGE trade model with diminishing returns in agriculture and realistic assumptions about consumer demand shows that while technical change in cottons and iron were major spurs to exportation of those specific goods, the need for food imports also stimulated exports generally. Incorporating trade data thus enriches our “new view.”
The First Bank of the United States and the Securities Market Crash of 1792
Authors: Cowen David J.
Published: July 2012

In 1791 the $10 million capitalization of the First Bank of the United States was vastly greater than the combined capital of all other banks. The Bank had an enormous impact on the economy within two months of opening its doors for business by flooding the market with its discounts and banknotes and then sharply reversing course and curtailing liquidity. Although the added liquidity initially helped push a rising securities market higher, the subsequent drain caused the first U.S. securities market crash by forcing speculators to sell their stocks. Several reasons are analyzed for the Bank's credit restriction.
Dynamical systems of type and their -algebras
Authors: ARA PERE , EXEL RUY , KATSURA TAKESHI
Published: July 2012

Given positive integers$n$and$m$, we consider dynamical systems in which (the disjoint union of)$n$copies of a topological space is homeomorphic to$m$copies of that same space. The universal such system is shown to arise naturally from the study of a C*-algebra denoted by${\cal O}_{m,n}$, which in turn is obtained as a quotient of the well-known Leavitt C*-algebra$L_{m,n}$, a process meant to transform the generating set of partial isometries of$L_{m,n}$into a tame set. Describing${\cal O}_{m,n}$as the crossed product of the universal$(m,n)$-dynamical system by a partial action of the free group$\mathbb {F}_{m+n}$, we show that${\cal O}_{m,n}$is not exact when$n$and$m$are both greater than or equal to 2, but the corresponding reduced crossed product, denoted by${\cal O}_{m,n}^r$, is shown to be exact and non-nuclear. Still under the assumption that$m,n\geq 2$, we prove that the partial action of$\mathbb {F}_{m+n}$is topologically free and that${\cal O}_{m,n}^r$satisfies property (SP) (small projections). We also show that${\cal O}_{m,n}^r$admits no finite-dimensional representations. The techniques developed to treat this system include several new results pertaining to the theory of Fell bundles over discrete groups.
Quaternary geology of the Inner Hebrides
Authors: Peacock J. D.
Published: July 2012

Synopsis

The Quaternary features and deposits provide a record of the geological history of the past 18,000 years and only a few elements of the landscape, such as the glaciated rock platforms and cliffs of marine origin, can be ascribed to earlier times. Mainland ice almost certainly covered the islands during the last glaciation, its retreat being temporarily reversed or halted perhaps more than once. There was a final well-marked, but short-lived episode of valley glaciation some 10,000 to 11,000 years ago. Glacial deposits, raised beaches, periglacial features, landslips and the post-glacial accumulations of peat, shell sand and diatomite are discussed briefly.
Inland waters in the Inner Hebrides
Authors: Maitland P. S. , Holden A. V.
Published: July 2012

Synopsis

The Inner Hebrides make up only a small proportion of the land area but a relatively higher percentage of the area of standing waters of Great Britain. Analyses of the 1:63,360 maps have provided the total numbers of standing and running waters on the islands (1,542 and 1,615 respectively) and are the basis for estimating the total resource there. The majority of lochs are small and relatively low lying. Most of the streams too are small and rarely larger than 4th order. Chemically, the waters are variable and range from some very acid nutrient-poor lochs on Islay to the unique marl lochs of Lismore. The algae of these islands have only occasionally been sampled and relatively little is known either about the higher aquatic plant communities—the ones studied are similar to those on the mainland. Few studies of the invertebrates of the inland waters have been carried out, and none of the surveys has been comprehensive. A review of the published and new data has enabled a broad account of the invertebrate communities to be presented. Only 15 species of fish occur here and most of the waters are dominated by the indigenous salmonids (salmon, trout and charr), sticklebacks or eels. Comparisons of the inland waters of the Inner Hebrides with those of other island groups (the Outer Hebrides and Shetlands) and the mainland of Scotland (especially Tayside) show that they have greater afiinities with the latter.
Ombrogenous mires in Islay and Mull
Authors: Lindsay R. A. , Riggall J. , Bignal E. M.
Published: July 2012

Synopsis

The vegetation and surface structure of two ombrogenous mires from the Inner Hebrides are described. Two-way indicator species analysis and hand sorting of these data are used to identify vegetation communities. The surface patterning of both sites is examined using levelling data which are related to the water table. From this, four significant surface features are recognised: hummock, ridge, hollow and pool. The relationship between the vegetation communities and these features is examined, and the two study sites subsequently compared in terms of these small-scale features. The ombrogenous mires of the Inner Hebrides are then related in the same way to other mire systems described by previous authors.
International Expansion — A United Kingdom Perspective: A Discussion Paper
Authors: Grenham D.J. , Chakraborty D.C. , Chatterjee A. , Daelman P.J. , Heistermann B. , Hogg L. , Mungall J.R. , Porteous B.T. , Richards S.J. , Shum M.C. , Taylor J.
Published: July 2012

This paper looks at the reasons why a UK life insurance company would wish to consider expanding into an overseas market, the factors it ought to bear in mind when deciding upon which country or countries to enter and the entry routes open to a company wishing to expand overseas.

By way of examples of overseas life insurance markets, the paper provides a detailed description of the German and Indian life insurance markets.
Impact of folic acid fortification of flour on neural tube defects: a systematic review
Authors: Castillo-Lancellotti Cecilia , Tur Josep A , Uauy Ricardo
Published: July 2012

Objective

To review the impact of folic acid fortification of flour on the prevalence of neural tube defects (NTD).

Design

Systematic review of the literature on MEDLINE via PubMed, Scopus, OvidSP and LILACS (Latin American and Caribbean Health Sciences Literature) reporting the impact of folic acid fortification of flour on the prevalence of NTD in 2000–2011. Focusing on Santiago of Chile's birth defects registry (1999–2009) and the monitoring of flour fortification, we analysed the prevalence (NTD cases/10 000 births) pre and post flour fortification and the percentile distribution of folic acid content in flour (2005–2009). We explored the potential association between median folic acid in flour (mg/kg) and the prevalence of NTD.

Setting

Chile, Argentina, Brazil, Canada, Costa Rica, Iran, Jordan, South Africa and the USA.

Subjects

Live births and stillbirths.

Results

Twenty-seven studies that met inclusion criteria were evaluated. Costa Rica showed a significant reduction in NTD (∼60 %). Prevalence in Chile decreased from 18·6 to 7·3/10 000 births from 1999 to 2007 and showed a slight increase to 8·5 in 2008–2009, possibly due to changes in fortification limits. When we related the prevalence of NTD with levels of flour fortification, the lowest prevalence was observed at a folic acid level of 1·5 mg/kg.

Conclusions

Fortification of flour with folic acid has had a major impact on NTD in all countries where this has been reported. Chile showed a 55 % reduction in NTD prevalence between 1999 and 2009. There is a need to constantly monitor the levels of flour fortification to maximize benefits and prevent the potential risk of folic acid excess, moreover to be vigilant for any new adverse effects associated with excess.
Survey of nutrition knowledge of physicians in Kuwait
Authors: Allafi Ahmad R , Alajmi Fahhad , Al-Haifi Ahmad
Published: July 2012

Objective

The objective of the present study was to determine whether nutrition knowledge differs between male and female physicians working in Kuwait City, Kuwait.

Design

The study employed a cross-sectional analysis of physician's nutrition knowledge by using a sixteen-item multiple-choice questionnaire.

Setting

Governmental hospitals in Kuwait City, Kuwait.

Subjects

One hundred Kuwaiti physicians (fifty males; fifty females) working in Kuwait City, Kuwait.

Results

A response rate of 73 % was achieved (forty males; thirty-three females). The mean percentage of correctly answered questions was 60 %. The male and female physicians averaged 56 % and 65 % of correct responses, respectively (P= 0·042). However, only for two questions did male and female physicians’ scores differ significantly (P< 0·05). The two age groups (<40 years; ≥40 years) had equal mean total correct scores (60 %,P= 0·935). Physicians’ knowledge was greatest for topics that have received a great deal of media coverage in Kuwait. Most (70 %) of the physicians described their nutrition knowledge as ‘moderate’.

Conclusions

Physicians in Kuwait gave inaccurate information regarding common problems in Kuwaitis such as obesity, hypertension and osteoporosis. In view of the public's perception of the role of the physician in providing nutrition advice, it is imperative that nutrition and diet training be part of continuing medical education to bridge these deficiencies in physicians’ knowledge.
Changing the Base: Legal Implications of Scientific Criteria and Methodological Standards on what Constitutes Good Marine Environmental Status
Authors: Markus Till
Published: July 2012

The Decision on Criteria and Methodological Standards on Good Environmental Status of Marine Waters provides the conceptual framework for the assessment and valuation of the marine waters of EU Member States. In particular, it provides concepts for defining what constitutes good marine environmental status – a status which Member States are obligated to achieve by the year 2020 under the 2008 Marine Strategy Framework Directive. This article aims to elucidate the epistemic and normative dimensions of scientific criteria and methodological standards, as well as their importance in the legal treatment of the marine environment of the EU. The article also assesses how and to what extent the transnational process leading up to the Decision was structured, surveying existing ideas and perspectives as to what exactly constitutes good environmental status, and examining whether the structure of the Decision ensures that those affected by it would want to accept it.
Magnetism of outdoor and indoor settled dust and its utilization as a tool for revealing the effect of elevated particulate air pollution on cardiovascular mortality
Authors: Jordanova Diana , Jordanova Neli , Lanos Philippe , Petrov Petar , Tsacheva Tsenka
Published: July 2012

Settled indoor and outdoor dusts in urban environment represent an important source of secondary pollution. Magnetic characteristics of the settled dust from six cities in Bulgaria are explored, allowing comparison on a national (country) scale. Monthly variations of the mass‐specific magnetic susceptibilities (χindoor) and (χoutdoor) and calculated dust loading rates for a period of 17 months do not show seasonal variability, probably due to the dominant role of traffic‐related emissions and soil‐derived particles in the settled dust. The main magnetic mineral is magnetite, present as spherules and irregular particles of pseudo‐single‐domain grain sizes. Systematically lower remanence coercivities are obtained for outdoor dusts when compared with the corresponding indoor samples, implying that penetration of smaller particles of ambient origin indoors is the main source of the indoor dust. Mean yearly values of the ratio (χindoor/χoutdoor) for each city show statistically significant correlation with mortality due to cardiovascular diseases. This ratio reveals the source‐ and site‐specific importance of the anthropogenically derived toxicogenic fraction. Heavy metal content of the settled dust is related to the contribution from several pollution sources (soil‐derived, combustion and industrial), discriminated through analysis of principal components. SEM/EDX analyses reveal abundant presence of anthopogenic Fe‐containing spherules, irregular particles and diesel exhaust conglomerates. High molecular weight polyaromatic hydrocarbons (PAH) dominate the total PAH content of the outdoor dust samples. The observed linear correlation between total PAH content, coercivity of remanence and the ratio Mrs/χ suggest either adsorption of PAHs on iron oxide particles and especially magnetite, or emission related increase in total PAH concentration along with a decrease of effective magnetic grain size of the accompanying magnetic fraction.
Shifting balance of thermokarst lake ice regimes across the Arctic Coastal Plain of northern Alaska
Authors: Arp C. D. , Jones B. M. , Lu Z. , Whitman M. S.
Published: July 2012

The balance of thermokarst lakes with bedfast‐ and floating‐ice regimes across Arctic lowlands regulates heat storage, permafrost thaw, winter‐water supply, and over‐wintering aquatic habitat. Using a time‐series of late‐winter synthetic aperture radar (SAR) imagery to distinguish lake ice regimes in two regions of the Arctic Coastal Plain of northern Alaska from 2003–2011, we found that 18% of the lakes had intermittent ice regimes, varying between bedfast‐ice and floating‐ice conditions. Comparing this dataset with a radar‐based lake classification from 1980 showed that 16% of the bedfast‐ice lakes had shifted to floating‐ice regimes. A simulated lake ice thinning trend of 1.5 cm/yr since 1978 is believed to be the primary factor driving this form of lake change. The most profound impacts of this regime shift in Arctic lakes may be an increase in the landscape‐scale thermal offset created by additional lake heat storage and its role in talik development in otherwise continuous permafrost as well as increases in over‐winter aquatic habitat and winter‐water supply.
Pc2 EMIC waves generated high off the equator in the dayside outer magnetosphere
Authors: Liu Y. H. , Fraser B. J. , Menk F. W.
Published: July 2012

It is generally accepted that electromagnetic ion cyclotron (EMIC) waves are generated around the equatorial regions and propagate toward the high latitude ionospheres in both hemispheres. Here we describe a prolonged EMIC wave event in the Pc2 (0.1–0.2 Hz) frequency band above the He+ cyclotron frequency detected by the four Cluster satellites as they traversed sunward from L∼ 13 in the outer magnetosphere to the magnetopause, over 13°–20° magnetic latitude north of the equator and across the high latitude cusp region near local magnetic noon. Wave packet energy propagated dominantly along the geomagnetic field direction, confirming this was a traveling EMIC wave rather than a toroidal field line resonance. The energy packets propagated in alternating directions rather than uni‐directionally from the equator, implying the wave source was located in a high latitude region away from the equator, where a minimum in the B field is located. The CIS‐CODIF H+ion data provided evidence that the waves were generated locally via the ion cyclotron instability. We believe the off‐equatorial minimum magnetic field regions may be important source regions for these waves in the outer magnetosphere.
Height distribution of Joule heating and its influence on the thermosphere
Authors: Huang Yanshi , Richmond Arthur D. , Deng Yue , Roble Ray
Published: July 2012

The National Center for Atmospheric Research Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (NCAR TIE‐GCM) is employed to quantify the influence of Joule heating at different altitudes on the neutral temperature and density at 400 km for solar minimum and maximum conditions. The results show that high‐altitude Joule heating is more efficient than low‐altitude heating in affecting the upper thermosphere. Most of the Joule heating is deposited under 150 km, and the largest Joule heating deposition per scale height happens at about 125 km, independent of solar activity. However, the temperature and density changes at 400 km are largest for heat deposited at ∼140 km for solar minimum and ∼263 km for solar maximum. The timescale for the thermospheric response varies with the altitude of heating. Joule heating deposited at lower heights needs more time to conduct upward, and it takes more time for the thermosphere at 400 km to approach a steady state. A simple one‐dimensional model is utilized to explain how the amplitude and characteristic timescale of the upper‐thermosphere response to Joule heating depends on the height of heat input. The characteristic response timescale for heat deposited around 135 km is ∼6 hours, while that for heat deposited around 238 km is ∼0.5 hours. The initial temperature response at 400 km to the high‐altitude heating is much stronger than the response to the low‐altitude heating, but the responses become comparable after about 4 days.
Variations in water vapor continuum radiative transfer with atmospheric conditions
Authors: Paynter D. , Ramaswamy V.
Published: July 2012

A newly formulated empirical water vapor continuum (the “BPS continuum”) is employed, in conjunction with ERA‐40 data, to advance the understanding of how variations in the water vapor profile can alter the impact of the continuum on the Earth's clear‐sky radiation budget. Three metrics are investigated: outgoing longwave radiation (OLR), Longwave surface downwelling radiation (SDR) and shortwave absorption (SWA). We have also performed a detailed geographical analysis on the impact of the BPS continuum upon these metrics and compared the results to those predicted by the commonly used MT CKD model. The globally averaged differences in these metrics when calculated with MT CKD 2.5 versus BPS were found to be 0.1%, 0.4% and 0.8% for OLR, SDR and SWA respectively. Furthermore, the impact of uncertainty upon these calculations is explored using the uncertainty estimates of the BPS model. The radiative response of the continuum to global changes in atmospheric temperature and water vapor content are also investigated. For the latter, the continuum accounts for up to 35% of the change in OLR and 65% of the change in SDR, brought about by an increase in water vapor in the tropics.
A probabilistic description of the bed load sediment flux: 1. Theory
Authors: Furbish David Jon , Haff Peter K. , Roseberry John C. , Schmeeckle Mark W.
Published: July 2012

We provide a probabilistic definition of the bed load sediment flux. In treating particle positions and motions as stochastic quantities, a flux form of the Master equation (a general expression of conservation) reveals that the volumetric flux involves an advective part equal to the product of an average particle velocity and the particle activity (the solid volume of particles in motion per unit streambed area), and a diffusive part involving the gradient of the product of the particle activity and a diffusivity that arises from the second moment of the probability density function of particle displacements. Gradients in the activity, instantaneous or time‐averaged, therefore effect a particle flux. Time‐averaged descriptions of the flux involve averaged products of the particle activity, the particle velocity and the diffusivity; the significance of these products depends on the scale of averaging. The flux form of the Exner equation looks like a Fokker‐Planck equation (an advection‐diffusion form of the Master equation). The entrainment form of the Exner equation similarly involves advective and diffusive terms, but because it is based on the joint probability density function of particle hop distances and associated travel times, this form involves a time derivative term that represents a lag effect associated with the exchange of particles between the static and active states. The formulation is consistent with experimental measurements and simulations of particle motions reported in companion papers.
A coral‐based reconstruction of sea surface salinity at Sabine Bank, Vanuatu from 1842 to 2007 CE
Authors: Gorman Meaghan K. , Quinn Terrence M. , Taylor Frederick W. , Partin Judson W. , Cabioch Guy , Austin James A. , Pelletier Bernard , Ballu Valérie , Maes Christophe , Saustrup Steffen
Published: July 2012

Climate variability associated with the El Niño Southern Oscillation (ENSO) results in large sea‐surface temperature (SST) and sea‐surface salinity (SSS) anomalies in many regions of the tropical Pacific Ocean. We investigate interannual changes in SSS driven by ENSO in the southwestern Pacific at Sabine Bank, Vanuatu (SBV, 166.04°E, 15.94°S) using monthly variations in coralδ18O from 1842 to 2007 CE. We develop and apply a coral δ18O‐SSS transfer function, which is assessed using a calibration‐verification exercise (1970–2007 CE). The 165‐year reconstructed SSS record contains a prominent trend toward freshening from 1842 to 2007 CE; mean SSS for 1842–1872 CE is 35.46 ± 0.28 psu, which contrasts with a mean value of 34.85 ± 0.31 psu for 1977–2007 CE, with a freshening trend during the latter part of the 20th century that is not unprecedented with respect to the overall record. Variance in the record is concentrated in the interannual (42%) and interdecadal (29%) bands. The SBV‐SSS record matches well with a similarly reconstructed SSS time series at Malo Channel, Vanuatu, which is located ∼120 km to the east of SBV. This regional signal is likely driven by ENSO‐related changes in the SPCZ and interdecadal changes in surface water advection. The pattern of interdecadal variability at SBV agrees reasonably well with coral records of interdecadal variability from Fiji and Tonga, especially in the pre‐1940 portions of the records, further evidence for the regional extent of the salinity signal at Sabine Bank, Vanuatu.
Impact of restriction of the Atlantic‐Mediterranean gateway on the Mediterranean Outflow Water and eastern Atlantic circulation during the Messinian
Authors: Pérez‐Asensio J. N. , Aguirre J. , Schmiedl G. , Civis J.
Published: July 2012

Messinian foraminiferal stable oxygen and carbon isotopes of the Montemayor‐1 core (Guadalquivir Basin, SW Spain) have been investigated. This record is exceptional to study the Mediterranean Outflow Water (MOW) impact on the Atlantic meridional overturning circulation (AMOC) and global climate during the Messinian because the core is near the Guadalhorce Corridor, the last Betic gateway to be closed during the early Messinian. Our results allow dating accurately its closure at 6.18 Ma. Constant benthicδ18O values, high difference between benthic and planktonicδ18O, and low sedimentation rates before 6.18 Ma indicate the presence of a two‐layer water column, with bottom winnowing due to an enhanced Mediterranean outflow current. The enhanced contribution of dense MOW to the North Atlantic Ocean likely fostered the formation of North Atlantic Deep Water (NADW). After 6.18 Ma, benthicδ18O values parallel that of the global glacioeustatic curve, the difference between benthic and planktonicδ18O is low, and sedimentation rates considerably increased. This indicates a good vertical mixing of the water column, interruption of the MOW, and a dominant glacioeustatic control on the isotopic signatures. According to the role of MOW in the modern Atlantic thermohaline circulation, the reduction of the MOW after the closure of the Guadalhorce Corridor might have resulted in a decreased NADW formation rate between 6.0 and 5.5 Ma weakening the AMOC and promoting northern hemisphere cooling. After the Gibraltar Strait opening, the restoration of the MOW and related salt export from the Mediterranean could have promoted an enhanced NADW formation.
The (bi)sexual brain
Authors: Crews David
Published: July 2012

When it comes to sexual behaviour in vertebrates, the two sexes are more alike than different. Yet whilst their bodies are usually male or female, their brains are bisexual and intrinsically capable of behaving as either sex.
RSK phosphorylates SOS1 creating 14-3-3-docking sites and negatively regulating MAPK activation
Authors: Saha Madhurima , Carriere Audrey , Cheerathodi Mujeeburahiman , Zhang Xiaocui , Lavoie Geneviève , Rush John , Roux Philippe P. , Ballif Bryan A.
Published: July 2012

The extent and duration of MAPK (mitogen-activated protein kinase) signalling govern a diversity of normal and aberrant cellular outcomes. Genetic and pharmacological disruption of the MAPK-activated kinase RSK (ribosomal S6 kinase) leads to elevated MAPK activity indicative of a RSK-dependent negative feedback loop. Using biochemical, pharmacological and quantitative MS approaches we show that RSK phosphorylates the Ras activator SOS1 (Son of Sevenless homologue 1) in cultured cells on two C-terminal residues, Ser1134 and Ser1161. Furthermore, we find that RSK-dependent SOS1 phosphorylation creates 14-3-3-binding sites. We show that mutating Ser1134 and Ser1161 disrupts 14-3-3 binding and modestly increases and extends MAPK activation. Together these data suggest that one mechanism whereby RSK negatively regulates MAPK activation is via site-specific SOS1 phosphorylation.
Investigation of the hydrogen bonding in ice Ih by first-principles density function methods
Authors: Zhang P. , Tian L. , Zhang Z. P. , Shao G. , Li J. C.
Published: July 2012

It is a well recognized difficult task to simulate the vibrational dynamics of ices using the density functional theory (DFT), and there has thus been rather limited success in modelling the inelastic neutron scattering (INS) spectra for even the simplest structure of ice, ice Ih, particularly in the translational region below 400 cm−1. The reason is partly due to the complex nature of hydrogen bonding (H-bond) among water-water molecules which require considerable improvement of the quantum mechanical simulation methods, and partly owing to the randomness of protons in ice structures which often requires simulation of large super-lattices. In this report, we present the first series of successful simulation results for ice Ih using DFT methods. On the basis of the recent advancement in the DFT programs, we have achieved for the first time theoretical outcomes that not only reproduce the rotational frequencies between 500 to 1200 cm−1 for ice Ih, but also the two optic peaks at ∼240 and 320 cm−1 in the translational region of the INS spectra [J. C. Li, J. Chem. Phys 105, 6733 (1996)]10.1063/1.472525. Besides, we have also investigated the impact of pairwise configurations of H2O molecules on the H-bond and found that different proton arrangements of pairwise H2O in the ice Ih crystal lattice could not alter the nature of H-bond as significantly as suggested in an early paper [J. C. Li and D. K. Ross, Nature (London) 365, 327 (1993)]10.1038/365327a0, i.e., reproducing the two experimental optic peaks do not need to invoke the two H-bonds as proposed in the previous model which led to considerable debates. The results of this work suggest that the observed optic peaks may be attributed to the coupling between the two bands of H-O stretching modes in H2O. The current computational work is expected to shed new light on the nature of the H-bonds in water, and in addition to offer a new approach towards probing the interaction between water and biomaterials for which H-bond is essential.
Successive elimination of shear layers by a hierarchy of constraints in inviscid spherical-shell flows
Authors: Livermore Philip W. , Hollerbach Rainer
Published: July 2012

In a rotating spherical shell, an inviscid inertia-free flow driven by an arbitrary body force will have cylindrical components that are either discontinuous across, or singular on, the tangent cylinder, the cylinder tangent to the inner core and parallel to the rotation axis. We investigate this problem analytically, and show that there is an infinite hierarchy of constraints on this body force which, if satisfied, sequentially remove discontinuities or singularities in flow derivatives of progressively higher order. By splitting the solution into its equatorial symmetry classes, we are able to provide analytic expressions for the constraints and demonstrate certain inter-relations between them. We show numerically that viscosity smoothes any singularity in the azimuthal flow component into a shear layer, comprising inner and outer layers, either side of the tangent cylinder, of width O(E2/7) and O(E1/4), respectively, where E is the Ekman number. The shear appears to scale as O(E−1/3) in the equatorially symmetric case, although in a more complex fashion when considering equatorial antisymmetry, and attains a maximum value in either the inner or outer sublayers depending on equatorial symmetry. In the low-viscosity magnetohydrodynamic system of the Earth's core, magnetic tension within the fluid resists discontinuities in the flow and may dynamically adjust the body force in order that a moderate number of the constraints are satisfied. We speculate that it is violations of these constraints that excites torsional oscillations, magnetohydrodynamic waves that are observed to emanate from the tangent cylinder.
Drift kinetic effects on the resistive wall mode stability—Comparison between reversed field pinches and tokamaks
Authors: Wang Z. R. , Guo S. C. , Liu Y. Q.
Published: July 2012

The physics of kinetic effects on the resistive wall mode (RWM) stability is studied, and a comparison between reversed field pinch (RFP) and Tokamak configurations is made. The toroidal, magnetohydrodynamic (MHD)-kinetic hybrid stability code MARS-K, in which the drift kinetic effects are self-consistently incorporated into the MHD formulation, is upgraded with an extensive energy analysis module. In the tokamak configuration, the kinetic effect can stabilize the mode with very slow, or vanishing plasma rotation, due to the mode resonance with the toroidal precession drift of thermal trapped particles. In RFP, instead, stabilization of the RWM comes mainly from the ion acoustic Landau damping (i.e., the transit resonance of passing particles). In the high beta region, the critical flow rotation frequency required for the mode stabilization is predicted to be in the ion acoustic range. Detailed physical analyses, based on the perturbed potential energy components, have been performed to gain understanding of the stabilizing mechanism in the two different systems.
Facile characterization of ripple domains on exfoliated graphene
Authors: Choi Jin Sik , Kim Jin-Soo , Byun Ik-Su , Lee Duk Hyun , Hwang In Rok , Park Bae Ho , Choi Taekjib , Park Jeong Young , Salmeron Miquel
Published: July 2012

Ripples in graphene monolayers deposited on SiO2/Si wafer substrates were recently shown to give rise to friction anisotropy. High friction appears when the AFM tip slides in a direction perpendicular to the ripple crests and low friction when parallel. The direction of the ripple crest is, however, hard to determine as it is not visible in topographic images and requires elaborate measurements of friction as a function of angle. Here we report a simple method to characterize ripple crests by measuring the cantilever torsion signal while scanning in the non-conventional longitudinal direction (i.e., along the cantilever axis, as opposed to the usual friction measurement). The longitudinal torsion signal provides a much clearer ripple domain contrast than the conventional friction signal, while both signals show respective rotation angle dependences that can be explained using the torsion component of the normal reaction force exerted by the graphene ripples. We can also determine the ripple direction by comparing the contrast in torsion images obtained in longitudinal and lateral scans without sample rotation or complicated normalization.
Zonal flows in stellarators in an ambient radial electric field
Authors: Mishchenko Alexey , Kleiber Ralf
Published: July 2012

The linear dynamics of zonal flows is addressed in stellarator geometry in the presence of an ambient (neoclassical) radial electric field. Global gyrokinetic particle-in-cell simulations are used to study the properties of the residual flow and its dependence on the plasma parameters and magnetic geometry. Properties of the zonal flow are compared in different magnetic geometries.
An instrument for 3D x-ray nano-imaging
Authors: Holler M. , Raabe J. , Diaz A. , Guizar-Sicairos M. , Quitmann C. , Menzel A. , Bunk O.
Published: July 2012

We present an instrument dedicated to 3D scanning x-ray microscopy, allowing a sample to be precisely scanned through a beam while the angle of x-ray incidence can be changed. The position of the sample is controlled with respect to the beam-defining optics by laser interferometry. The instrument achieves a position stability better than 10 nm standard deviation. The instrument performance is assessed using scanning x-ray diffraction microscopy and we demonstrate a resolution of 18 nm in 2D imaging of a lithographic test pattern while the beam was defined by a pinhole of 3 μm in diameter. In 3D on a test object of copper interconnects of a microprocessor, a resolution of 53 nm is achieved.