bluuebunny/crossref_metadata_2025 huggingface dataset:
The phases and amplitudes of gravity waves propagating and dissipating in the thermosphere: Theory
Authors: Vadas S. L. , Nicolls M. J.
Published: March 2012

We derive the high‐frequency, compressible, dissipative dispersion and polarization relations for linear acoustic‐gravity waves (GWs) and acoustic waves (AWs) in a single‐species thermosphere. The wave amplitudes depend explicitly on time, consistent with a wave packet approach. We investigate the phase shifts and amplitude ratios between the GW components, which include the horizontal (uH′) and vertical (w′) velocity, density (ρ′), pressure (p′), and temperature (T′) perturbations. We show how GWs with large vertical wavelengths λz have dramatically different phase and amplitude relations than those with small λz. For zero viscosity, as ∣λz∣ increases, the phase between uH′ and w′ decreases from 0 to ∼−90°, the phase between uH′ and T′ decreases from ∼90 to 0°, and the phase between T′ and ρ′ decreases from ∼180 to 0° for λH ≫ ∣λz∣, where λH is the horizontal wavelength. This effect lessens substantially with increasing altitudes, primarily because the density scale height
increases. We show how in‐situ satellite measurements of either (1) the 3D neutral wind or (2) ρ′, T′, w′, and the cross‐track wind, can be used to infer a GW's λH, λz, propagation direction, and intrinsic frequency ωIr. We apply this theory to a GW observed by the DE2 satellite. We find a significant region of overlap in parameter space for 5 independent constraints (i.e., T′0/ρ′0, the phase shift between T′ and w′, and the distance between wave crests), which provides a good test and validation of this theory. In a companion paper, we apply this theory to ground‐based observations of a GW over Alaska.
Interhemispheric dynamical coupling to the southern mesosphere and lower thermosphere
Authors: Murphy D. J. , Alexander S. P. , Vincent R. A.
Published: March 2012

Wind observations obtained between 1995 and 2011 using the MF radar at Davis have been used to demonstrate the modifying role the quasi‐biennial oscillation (QBO) plays on some aspects of interhemispheric coupling identified by previous authors. The response of the meridional wind in the southern summer polar MLT to changes in winter stratospheric planetary wave activity is shown to change sign according to the phase of the QBO. The time delay associated with the coupling is also shown to vary with QBO phase, with an eastward QBO providing a more rapid response. Coupling to the MLT meridional winds is strongest in January. Parts of the mechanism currently proposed have been tested using UKMO assimilated observations. The signatures of some aspects of this mechanism are present in the data. However, some differences to the mechanism are also apparent, in particular the effectiveness of the mechanism near the equator. An explanation for the QBO modulation of the MLT wind response to interhemispheric coupling is proposed on the basis of these differences.
Electron pitch‐angle diffusion in radiation belts: The effects of whistler wave oblique propagation
Authors: Artemyev A. , Agapitov O. , Breuillard H. , Krasnoselskikh V. , Rolland G.
Published: March 2012

We calculated the electron pitch‐angle diffusion coefficients in the outer radiation belt forL‐shell ∼4.5 taking into account the effects of oblique whistler wave propagation. The dependence of the distribution of the angleθbetween the whistler wave vector and the background magnetic field on magnetic latitude is modeled after statistical results of Cluster wave angle observations. According to in‐situ observations, the mean value and the variance of theθdistribution rapidly increase with magnetic latitude. We found that inclusion of oblique whistler wave propagation led to a significant increase in pitch‐angle diffusion rates over those calculated under the assumption of parallel whistler wave propagation. The effect was pronounced for electrons with small equatorial pitch‐angles close to the loss cone and could result in as much as an order of magnitude decrease of the electron lifetimes. We show that the intensification of pitch‐angle diffusion can be explained by the contribution of higher order cyclotron resonances. By comparing the results of calculations obtained from two models of electron density distribution along field lines, we show that the effect of the intensification of pitch‐angle diffusion is stronger when electron density does not vary along field lines. The intensification of pitch‐angle diffusion and corresponding decrease of energetic electron lifetime result in significant modification of the rate of electron losses and should have an impact on formation and dynamics of the outer radiation belt.
Albedo evolution of seasonal Arctic sea ice
Authors: Perovich Donald K. , Polashenski Christopher
Published: March 2012

There is an ongoing shift in the Arctic sea ice cover from multiyear ice to seasonal ice. Here we examine the impact of this shift on sea ice albedo. Our analysis of observations from four years of field experiments indicates that seasonal ice undergoes an albedo evolution with seven phases; cold snow, melting snow, pond formation, pond drainage, pond evolution, open water, and freezeup. Once surface ice melt begins, seasonal ice albedos are consistently less than albedos for multiyear ice resulting in more solar heat absorbed in the ice and transmitted to the ocean. The shift from a multiyear to seasonal ice cover has significant implications for the heat and mass budget of the ice and for primary productivity in the upper ocean. There will be enhanced melting of the ice cover and an increase in the amount of sunlight available in the upper ocean.
Novel Mitochondrial Targets for Neuroprotection
Authors: Perez-Pinzon Miguel A , Stetler R Anne , Fiskum Gary
Published: March 2012

Mitochondrial dysfunction contributes to the pathophysiology of acute neurologic disorders and neurodegenerative diseases. Bioenergetic failure is the primary cause of acute neuronal necrosis, and involves excitotoxicity-associated mitochondrial Ca2+ overload, resulting in opening of the inner membrane permeability transition pore and inhibition of oxidative phosphorylation. Mitochondrial energy metabolism is also very sensitive to inhibition by reactive O2 and nitrogen species, which modify many mitochondrial proteins, lipids, and DNA/RNA, thus impairing energy transduction and exacerbating free radical production. Oxidative stress and Ca2+-activated calpain protease activities also promote apoptosis and other forms of programmed cell death, primarily through modification of proteins and lipids present at the outer membrane, causing release of proapoptotic mitochondrial proteins, which initiate caspase-dependent and caspase-independent forms of cell death. This review focuses on three classifications of mitochondrial targets for neuroprotection. The first is mitochondrial quality control, maintained by the dynamic processes of mitochondrial fission and fusion and autophagy of abnormal mitochondria. The second includes targets amenable to ischemic preconditioning, e.g., electron transport chain components, ion channels, uncoupling proteins, and mitochondrial biogenesis. The third includes mitochondrial proteins and other molecules that defend against oxidative stress. Each class of targets exhibits excellent potential for translation to clinical neuroprotection.
Microfluidics Reaction Technology (MRT) for Continuous Production for Nano-formulations of Drug Entities and Advanced Materials
Authors: Panagiotou T. , Chomistek K.J. , Fisher R.J.
Published: March 2012

Microfluidics Reaction Technology (MRT is a continuous processing technology used to produce stable nano-scale materials through crystallization, precipitation, emulsification, and chemical reactions. High purity materials with controlled structure and desired properties were produced successfully using this platform technology. The principles upon which this platform is based are the fundamental rates of mass, heat, and momentum transfer coupled with chemical reaction phenomena. The essential physical component is a continuous and scalable micro-reactor utilizing impinging jets. Flow throughput is characterized by high fluid velocities, up to 500 m/s, resulting in highly turbulent conditions and interactions at the nano-scale. In addition to size control, the technology offers control of morphologies and reaction selectivity. The unique design of this micro-reactor provides precise control of feed rates, mixing location and its intensity, and process time scales. Successful implementations of this platform technology include: (a) formation of drug nano-suspensions through crystallization, (b) nano-encapsulation of actives in polymers, and (c) chemical reacting systems that produce and/or utilize nano-species, such as suspensions and emulsions. The focus here is on the production of nano- emulsions and global system optimization. Results indicate that they can be formed in one step using MRT as opposed to the two step conventional process that requires the initial formation of a micro-emulsion. Also demonstrated are the reduced amounts of surfactants required for certain formulations to obtain stable nano-emulsions. Dependent upon process parameters, sizes in the range of 50-800 nm are easily obtained.
Rheumatische Erkrankungen
Authors: Rehart S. , Henniger M.
Published: March 2012

Die häufigste Erkrankung des rheumatischen Formenkreises ist die rheumatoide Arthritis. Sie befällt überwiegend die Gelenke des Bewegungsapparats und führt dort zu schmerzhaften Gelenkschwellungen mit Funktionseinschränkungen und im Verlauf zu typischen Deformierungen und Destruktionen. Als entzündliche Systemerkrankung kann die rheumatoide Arthritis aber auch Sehnenscheiden, Schleimbeutel, Gefäße, Augen und die inneren Organe betreffen.

Dieser Artikel ist mit der Diagnostik befasst und beschreibt die medikamentösen und die begleitenden konservativen Therapieoptionen der rheumatoiden Arthritis. Versagt dieser konservative Ansatz, kommen operative Therapiemaßnahmen zum Einsatz. Ein weiterer Artikel, der zu einem späteren Zeitpunkt erscheinen wird, stellt diese chirurgischen Therapiemöglichkeiten dar.
Giant converse magnetoelectric effect in multi-push-pull mode Metglas/Pb(Zr,Ti)O3/Metglas laminates
Authors: Li Menghui , Wang Yaojin , Hasanyan Davresh , Li Jiefang , Viehland D.
Published: March 2012

The converse magnetoelectric (CME) effect was investigated theoretically and experimentally for multi-push-pull mode Metglas/Pb(Zr,Ti)O3/Metglas laminates. The experimental and theoretical values of the CME coefficient (αB) exhibited similar trends. A large αB = 6.94 G/V was observed at 1 kHz under a dc magnetic bias of 11 Oe. At an electromechanical resonance frequency of 29.6 kHz, the laminate exhibited a giant value of αB = 79.5 G/V. These results show significantly enhanced CME effects in multi-push-pull mode laminates, compared to previously reported ones with different structures and materials.
Enhancing the photoluminescence of ferroelectric liquid crystal by doping with ZnS quantum dots
Authors: Kumar A. , Prakash J. , Deshmukh Abhay D. , Haranath D. , Silotia P. , Biradar A. M.
Published: March 2012

We report the enhancement in photoluminescence (PL) intensity and shift in spectral energy band of ferroelectric liquid crystal (FLC) doped with ZnS quantum dots (QDs). The emission from ZnS QDs has combined constructively with that of FLC to give enhanced PL intensity. On the other hand, the smectic phases of FLC provided strong light scattering and hence improved the PL intensity of the composite. The change in effective refractive index of FLC due to different concentrations of ZnS QDs has caused the red shift. Our observations will certainly provide a promising tool in the realization of enhanced PL-LC display devices.
Seed traits and seed bank longevity of wet sclerophyll forest shrubs
Authors: Campbell Monica L. , Clarke Peter J. , Keith David A.
Published: March 2012

In wet sclerophyll forests seedling recruitment either occurs after intermittent fire events or continuously during intervals between fires in gaps created by small-scale disturbances. The dormancy and dispersal characteristics of seeds will influence how plant species exploit these contrasting recruitment opportunities. For example, long-lived seed banks may be crucial for persistence of species that are unable to recruit during intervals between fires if the length of fire intervals exceeds the life span of standing plants (senescence risk). To better understand mechanisms of population persistence during prolonged absence of fire in montane wet sclerophyll forests, we studied seed bank dynamics in four understorey species. We chose two species thought to have fire event-driven recruitment, Banksia integrifolia subsp. monticola (Proteaceae) and Goodia lotifolia (Fabaceae), and two species that are thought to have canopy gap-phase recruitment, Trochocarpa laurina (Ericaceae) and Tasmannia stipitata (Winteraceae). We measured seed rain, seed bank density and used seeds buried in nylon mesh bags to estimate rates of seed decay in the soil over time. All species produced a substantial seed crop on an annual basis. The annual seed crop in three species (G. lotifolia, T. stipitata and T. laurina) was released in a dormant state and developed a persistent seed bank, while one species (B. integrifolia) lacked dormancy and rapidly germinated under laboratory and field conditions. Seed bank characteristics of G. lotifolia appear to promote episodic recruitment after large landscape-scale fires, those of B. integrifolia appear to promote more continuous recruitment in response to smaller fires and other disturbances that avoid widespread mortality of established plants, while seed bank characteristics of T. stipitata and T. laurina may facilitate both episodic and continuous recruitment under respective types of disturbance. The four species appeared to have varied vulnerabilities and mechanisms for reducing immaturity risk and senescence risk to persistence of their populations under recurrent disturbance. Dormancy, seed bank longevity and seed rain are likely to be useful syndromes for predicting the response of wet sclerophyll forest understorey species to changed disturbance regimes.
Hierarchical clustering of brain activity during human nonrapid eye movement sleep
Authors: Boly Mélanie , Perlbarg Vincent , Marrelec Guillaume , Schabus Manuel , Laureys Steven , Doyon Julien , Pélégrini-Issac Mélanie , Maquet Pierre , Benali Habib
Published: March 2012

Consciousness is reduced during nonrapid eye movement (NREM) sleep due to changes in brain function that are still poorly understood. Here, we tested the hypothesis that impaired consciousness during NREM sleep is associated with an increased modularity of brain activity. Cerebral connectivity was quantified in resting-state functional magnetic resonance imaging times series acquired in 13 healthy volunteers during wakefulness and NREM sleep. The analysis revealed a modification of the hierarchical organization of large-scale networks into smaller independent modules during NREM sleep, independently from EEG markers of the slow oscillation. Such modifications in brain connectivity, possibly driven by sleep ultraslow oscillations, could hinder the brain's ability to integrate information and account for decreased consciousness during NREM sleep.
Efficacy of vaccination with recombinant vaccinia and fowlpox vectors expressing NY-ESO-1 antigen in ovarian cancer and melanoma patients
Authors: Odunsi Kunle , Matsuzaki Junko , Karbach Julia , Neumann Antje , Mhawech-Fauceglia Paulette , Miller Austin , Beck Amy , Morrison Carl D. , Ritter Gerd , Godoy Heidi , Lele Shashikant , duPont Nefertiti , Edwards Robert , Shrikant Protul , Old Lloyd J. , Gnjatic Sacha , Jäger Elke
Published: March 2012

Recombinant poxviruses (vaccinia and fowlpox) expressing tumor-associated antigens are currently being evaluated in clinical trials as cancer vaccines to induce tumor-specific immune responses that will improve clinical outcome. To test whether a diversified prime and boost regimen targeting NY-ESO-1 will result in clinical benefit, we conducted two parallel phase II clinical trials of recombinant vaccinia-NY-ESO-1 (rV-NY-ESO-1), followed by booster vaccinations with recombinant fowlpox-NY-ESO-1 (rF-NY-ESO-1) in 25 melanoma and 22 epithelial ovarian cancer (EOC) patients with advanced disease who were at high risk for recurrence/progression. Integrated NY-ESO-1-specific antibody and CD4
+
and CD8
+
T cells were induced in a high proportion of melanoma and EOC patients. In melanoma patients, objective response rate [complete and partial response (CR+PR)] was 14%, mixed response was 5%, and disease stabilization was 52%, amounting to a clinical benefit rate (CBR) of 72% in melanoma patients. The median PFS in the melanoma patients was 9 mo (range, 0–84 mo) and the median OS was 48 mo (range, 3–106 mo). In EOC patients, the median PFS was 21 mo (95% CI, 16–29 mo), and median OS was 48 mo (CI, not estimable). CD8
+
T cells derived from vaccinated patients were shown to lyse NY-ESO-1-expressing tumor targets. These data provide preliminary evidence of clinically meaningful benefit for diversified prime and boost recombinant pox-viral-based vaccines in melanoma and ovarian cancer and support further evaluation of this approach in these patient populations.
Transcriptional requirements of the distal heavy-strand promoter of mtDNA
Authors: Zollo Ornella , Tiranti Valeria , Sondheimer Neal
Published: March 2012

The heavy strand of mtDNA contains two promoters with nonoverlapping functions. The role of the minor heavy-strand promoter (HSP2) is controversial, because the promoter has been difficult to activate in an in vitro system. We have isolated HSP2 by excluding its interaction with the more powerful HSP1 promoter, and we find that it is transcribed efficiently by recombinant mtRNA polymerase and mitochondrial transcription factor B2. The mitochondrial transcription factor A is not required for initiation, but it has the ability to alternatively activate and repress the HSP2 transcriptional unit depending on the ratio between mitochondrial transcription factor A and other transcription factors. The positioning of transcriptional initiation agrees with our current understanding of HSP2 activity in vivo. Serial deletion of HSP2 shows that only proximal sequences are required. Several mutations, including the disruption of a polycytosine track upstream of the HSP2 initiation site, influence transcriptional activity. Transcription from HSP2 is also observed when HeLa cell mitochondrial extract is used as the source of mitochondrial polymerase, and this transcription is maintained when HSP2 is provided in proper spacing and context to the HSP1 promoter. Studies of the linked heavy-strand promoters show that they are differentially regulated by ATP dosage. We conclude that HSP2 is transcribed and has features that allow it to regulate mitochondrial mRNA synthesis.
Evidence for elevated mutation rates in low-quality genotypes
Authors: Sharp Nathaniel P. , Agrawal Aneil F.
Published: March 2012

The deleterious mutation rate plays a key role in a number of important topics in biology, from mating system evolution to human health. Despite this broad significance, the nature and causes of variation in mutation rate are poorly understood, especially in multicellular organisms. We test whether genetic quality, the presence or absence of deleterious alleles, affects the mutation rate in
Drosophila melanogaster
by using a modified mutation accumulation approach. We find evidence that genotypes constructed to carry deleterious “treatment” alleles on one chromosome during mutation accumulation experience an elevated mutation rate on a different chromosome. Further, this elevation is correlated with the effect of the treatment alleles on phenotypic condition, measured as body mass. Treatment alleles that reduce mass by 10% cause a doubling in the rate of mutational decline. Our results show that mutation rates are sensitive to genetic stress, such that individuals with low-quality genotypes will produce offspring of even lower genetic quality, in a mutational positive feedback loop. This type of variation in mutation rate is expected to alter a variety of predictions based on mutation load theory and accelerate adaptation to new environments. Positive mutational feedback could affect human health by increasing the rate of germline mutation, and possibly somatic mutation, in individuals of poor health because of genetic or environmental stress.
Bruton's tyrosine kinase phosphorylates Toll-like receptor 3 to initiate antiviral response
Authors: Lee Koon-Guan , Xu Shengli , Kang Zi-Han , Huo Jianxin , Huang Mei , Liu Dingxiang , Takeuchi Osamu , Akira Shizuo , Lam Kong-Peng
Published: March 2012

Toll-like receptor 3 (TLR3) mediates antiviral response by recognizing double-stranded RNA. Its cytoplasmic domain is tyrosine phosphorylated upon ligand binding and initiates downstream signaling via the adapter TIR-containing adaptor inducing interferon–β (TRIF). However, the kinase responsible for TLR3 phosphorylation remains unknown. We show here that Bruton's tyrosine kinase (BTK)-deficient macrophages failed to secrete inflammatory cytokines and IFN-β upon TLR3 stimulation and were impaired in clearing intracellular dengue virus infection. Mutant mice were also less susceptible to
d
-galactosamine/p(I:C)-induced sepsis. In the absence of BTK, TLR3-induced phosphoinositide 3-kinase (PI3K), AKT and MAPK signaling and activation of NFκB, IRF3, and AP-1 transcription factors were all defective. We demonstrate that BTK directly phosphorylates TLR3 and in particular the critical Tyr759 residue. BTK point mutations that abrogate or led to constitutive kinase activity have opposite effects on TLR3 phosphorylation. Loss of BTK also compromises the formation of the downstream TRIF/receptor-interacting protein 1 (RIP1)/TBK1 complex. Thus, BTK plays a critical role in initiating TLR3 signaling.
Sensitive kinase assay linked with phosphoproteomics for identifying direct kinase substrates
Authors: Xue Liang , Wang Wen-Horng , Iliuk Anton , Hu Lianghai , Galan Jacob A. , Yu Shuai , Hans Michael , Geahlen Robert L. , Tao W. Andy
Published: March 2012

Our understanding of the molecular control of many disease pathologies requires the identification of direct substrates targeted by specific protein kinases. Here we describe an integrated proteomic strategy, termed kinase assay linked with phosphoproteomics, which combines a sensitive kinase reaction with endogenous kinase-dependent phosphoproteomics to identify direct substrates of protein kinases. The unique in vitro kinase reaction is carried out in a highly efficient manner using a pool of peptides derived directly from cellular kinase substrates and then dephosphorylated as substrate candidates. The resulting newly phosphorylated peptides are then isolated and identified by mass spectrometry. A further comparison of these in vitro phosphorylated peptides with phosphopeptides derived from endogenous proteins isolated from cells in which the kinase is either active or inhibited reveals new candidate protein substrates. The kinase assay linked with phosphoproteomics strategy was applied to identify unique substrates of spleen tyrosine kinase (Syk), a protein-tyrosine kinase with duel properties of an oncogene and a tumor suppressor in distinctive cell types. We identified 64 and 23 direct substrates of Syk specific to B cells and breast cancer cells, respectively. Both known and unique substrates, including multiple centrosomal substrates for Syk, were identified, supporting a unique mechanism that Syk negatively affects cell division through its centrosomal kinase activity.
Maximum Neutral Buoyancy Depth of Juvenile Chinook Salmon: Implications for Survival during Hydroturbine Passage
Authors: Pflugrath Brett D. , Brown Richard S. , Carlson Thomas J.
Published: March 2012

This study investigated the maximum depth at which juvenile Chinook salmon Oncorhynchus tshawytscha can acclimate by attaining neutral buoyancy. The depth of neutral buoyancy is dependent upon the volume of gas within the swim bladder, which greatly influences the occurrence of injuries to fish passing through hydroturbines. We used two methods to obtain maximum swim bladder volumes that were transformed into depth estimations—the increased excess mass test and the swim bladder rupture test. In the increased excess mass test, weights were surgically added to the exterior of the fish, requiring the fish to increase swim bladder volume in order to remain neutrally buoyant. The swim bladder rupture test entailed removing and artificially increasing swim bladder volume through decompression. From these tests, we estimate the maximum acclimation depth for juvenile Chinook salmon is a median of 6.7 m (range = 4.6–11.6 m). These findings have important implications to survival estimates, studies using tags, hydropower operations, and survival of juvenile salmon that pass through large Kaplan turbines typical of those found within the Columbia and Snake River hydropower system.
Stable Isotopes of Carbon and Nitrogen Indicate Differences in Marine Ecology between Wild and Hatchery‐Produced Steelhead
Authors: Quinn Thomas P. , Seamons Todd R. , Johnson Susan P.
Published: March 2012

Hatchery‐produced anadromous salmonids often differ from their wild conspecifics in behavior, growth, and survival after release, but our understanding of their comparative ecology at sea is very limited. We used stable isotopes of carbon and nitrogen to test the null hypothesis that hatchery‐produced steelhead Oncorhynchus mykiss from Forks Creek in southwestern Washington would be similar in trophic level and marine distribution to wild fish from the same river. Analysis of scale samples from 30 fish of each type that had migrated to sea in 2001 and 2002 (120 fish in all) revealed significant effects of year and origin on both C and N. The values for δ15N were consistent with a higher trophic level for the wild fish (mean = 10.82, SD = 0.57) than for the hatchery fish (mean = 10.51, SD = 0.59), and the δ13C values were consistent with more reliance on nearshore sources of C by wild fish (wild fish mean = −16.52, SD = 0.30; hatchery fish mean = −16.73, SD = 0.31). The wild fish showed no relationship between body size and isotope values, but among the hatchery fish larger individuals tended to have lower δ15N values and more negative δ13C values. The wild fish were, on average, larger than the hatchery fish but had higher δ15N values and less negative δ13C values. These patterns are the opposite of what would be expected from a difference in growth rate, suggesting that the differences arose from ecological processes rather than a size or growth effect. Interactions between trophic level and location prevent a determination of which features of the marine ecology differed between wild and hatchery fish, but either factor could result from differences in the genetic background and rearing history of wild and hatchery fish and could contribute to differences in their performance (growth and survival) at sea.
Nucleophosmin/B23 activates Aurora A at the centrosome through phosphorylation of serine 89
Authors: Reboutier David , Troadec Marie-Bérengère , Cremet Jean-Yves , Fukasawa Kenji , Prigent Claude
Published: March 2012

Aurora A (AurA) is a major mitotic protein kinase involved in centrosome maturation and spindle assembly. Nucleophosmin/B23 (NPM) is a pleiotropic nucleolar protein involved in a variety of cellular processes including centrosome maturation. In the present study, we report that NPM is a strong activator of AurA kinase activity. NPM and AurA coimmunoprecipitate and colocalize to centrosomes in G2 phase, where AurA becomes active. In contrast with previously characterized AurA activators, NPM does not trigger autophosphorylation of AurA on threonine 288. NPM induces phosphorylation of AurA on serine 89, and this phosphorylation is necessary for activation of AurA. These data were confirmed in vivo, as depletion of NPM by ribonucleic acid interference eliminated phosphorylation of CDC25B on S353 at the centrosome, indicating a local loss of AurA activity. Our data demonstrate that NPM is a strong activator of AurA kinase activity at the centrosome and support a novel mechanism of activation for AurA.
Hierarchical self-assembly of chiral fibres from achiral particles
Authors: Prybytak P. , Frith W. J. , Cleaver D. J.
Published: March 2012

We investigate, by molecular dynamics simulation, the behaviour of discotic particles in a solvent of Lennard-Jones spheres. When chromonic disc–sphere interactions are imposed on these systems, three regimes of self-assembly are observed. At moderate temperatures, numerous short threads of discs develop, but these threads remain isolated from one another. Quenching to low temperatures, alternatively, causes all of the discs to floc into a single extended aggregate which typically comprises several distinct sections and contains numerous packing defects. For a narrow temperature range between these regimes, however, defect-free chiral fibres are found to freely self-assemble. The spontaneous chirality of these fibres results from frustration between the hexagonal packing and interdigitation of neighbouring threads, the pitch being set by the particle shape. This demonstration of aggregate-wide chirality emerging owing to packing alone is pertinent to many biological and synthetic hierarchically self-assembling systems.
Optimal shape and motion of undulatory swimming organisms
Authors: Tokić Grgur , Yue Dick K. P.
Published: March 2012

Undulatory swimming animals exhibit diverse ranges of body shapes and motion patterns and are often considered as having superior locomotory performance. The extent to which morphological traits of swimming animals have evolved owing to primarily locomotion considerations is, however, not clear. To shed some light on that question, we present here the optimal shape and motion of undulatory swimming organisms obtained by optimizing locomotive performance measures within the framework of a combined hydrodynamical, structural and novel muscular model. We develop a muscular model for periodic muscle contraction which provides relevant kinematic and energetic quantities required to describe swimming. Using an evolutionary algorithm, we performed a multi-objective optimization for achieving maximum sustained swimming speedUand minimum cost of transport (COT)—two conflicting locomotive performance measures that have been conjectured as likely to increase fitness for survival. Starting from an initial population of random characteristics, our results show that, for a range of size scales, fish-like body shapes and motion indeed emerge whenUand COT are optimized. Inherent boundary-layer-dependent allometric scaling between body mass and kinematic and energetic quantities of the optimal populations is observed. The trade-off betweenUand COT affects the geometry, kinematics and energetics of swimming organisms. Our results are corroborated by empirical data from swimming animals over nine orders of magnitude in size, supporting the notion that optimizingUand COT could be the driving force of evolution in many species.
Variation in founder groups promotes establishment success in the wild
Authors: Forsman Anders , Wennersten Lena , Karlsson Magnus , Caesar Sofia
Published: March 2012

Environmental changes currently pose severe threats to biodiversity, and reintroductions and translocations are increasingly used to protect declining populations and species from extinction. Theory predicts that establishment success should be higher for more variable groups of dissimilar individuals. To test this ‘diversity promotes establishment’ hypothesis, we introduced colour polymorphic pygmy grasshoppers (
Tetrix subulata
) to different sites in the wild. The number of descendants found at the release sites the subsequent year increased with increasing number of colour morphs in the founder group, and variation in founder groups also positively affected colour morph diversity in the established populations. Since colour morphs differ in morphology, physiology, behaviour, reproductive life history and types of niche used, these findings demonstrate that variation among individuals in functionally important traits promotes establishment success under natural conditions, and further indicate that founder diversity may contribute to evolutionary rescue and increased population persistence.
Life-history theory, chronic childhood illness and the timing of first reproduction in a British birth cohort
Authors: Waynforth David
Published: March 2012

Life-history theoretical models show that a typical evolutionarily optimal response of a juvenile organism to high mortality risk is to reach reproductive maturity earlier. Experimental studies in a range of species suggest the existence of adaptive flexibility in reproductive scheduling to maximize fitness just as life-history theory predicts. In humans, supportive evidence has come from studies comparing neighbourhoods with different mortality rates, historical and cross-cultural data. Here, the prediction is tested in a novel way in a large (n= 9099), longitudinal sample using data comparing age at first reproduction in individuals with and without life-expectancy-reducing chronic disease diagnosed during childhood. Diseases selected for inclusion as chronic illnesses were those unlikely to be significantly affected by shifting allocation of effort away from reproduction towards survival; those which have comparatively large effects on mortality and life expectancy; and those which are not profoundly disabling. The results confirmed the prediction that chronic disease would associate with early age at first reproduction: individuals growing up with a serious chronic disease were 1.6 times more likely to have had a first child by age 30. Analysis of control variables also confirmed past research findings on links between being raised father-absent and early pubertal development and reproduction.
A novel mammalian social structure in Indo-Pacific bottlenose dolphins (Tursiopssp.): complex male alliances in an open social network
Authors: Randić Srđan , Connor Richard C. , Sherwin William B. , Krützen Michael
Published: March 2012

Terrestrial mammals with differentiated social relationships live in ‘semi-closed groups’ that occasionally accept new members emigrating from other groups. Bottlenose dolphins (Tursiopssp.) in Shark Bay, Western Australia, exhibit a fission–fusion grouping pattern with strongly differentiated relationships, including nested male alliances. Previous studies failed to detect a group membership ‘boundary’, suggesting that the dolphins live in an open social network. However, two alternative hypotheses have not been excluded. Thecommunity defence modelposits that the dolphins live in a large semi-closed ‘chimpanzee-like’ community defended by males and predicts that a dominant alliance(s) will range over the entire community range. Themating season defence modelpredicts that alliances will defend mating-season territories or sets of females. Here, both models are tested and rejected: no alliances ranged over the entire community range and alliances showed extensive overlap in mating season ranges and consorted females. The Shark Bay dolphins, therefore, present a combination of traits that is unique among mammals: complex male alliances in an open social network. The open social network of dolphins is linked to their relatively low costs of locomotion. This reveals a surprising and previously unrecognized convergence between adaptations reducing travel costs and complex intergroup–alliance relationships in dolphins, elephants and humans.
Disentangling effects of uncertainties on population projections: climate change impact on an epixylic bryophyte
Authors: Ruete Alejandro , Yang Wei , Bärring Lars , Stenseth Nils Chr. , Snäll Tord
Published: March 2012

Assessment of future ecosystem risks should account for the relevant uncertainty sources. This means accounting for the joint effects of climate variables and using modelling techniques that allow proper treatment of uncertainties. We investigate the influence of three of the IPCC's scenarios of greenhouse gas emissions (special report on emission scenarios (SRES)) on projections of the future abundance of a bryophyte model species. We also compare the relative importance of uncertainty sources on the population projections. The whole chain global climate model (GCM)—regional climate model—population dynamics model is addressed. The uncertainty depends on both natural- and model-related sources, in particular on GCM uncertainty. Ignoring the uncertainties gives an unwarranted impression of confidence in the results. The most likely population development of the bryophyte
Buxbaumia viridis
towards the end of this century is negative: even with a low-emission scenario, there is more than a 65 per cent risk for the population to be halved. The conclusion of a population decline is valid for all SRES scenarios investigated. Uncertainties are no longer an obstacle, but a mandatory aspect to include in the viability analysis of populations.
Physical competition increases testosterone among Amazonian forager-horticulturalists: a test of the ‘challenge hypothesis’
Authors: Trumble Benjamin C. , Cummings Daniel , von Rueden Christopher , O'Connor Kathleen A. , Smith Eric A. , Gurven Michael , Kaplan Hillard
Published: March 2012

The challenge hypothesis posits that acute increases in testosterone (T) during male–male competition enhance performance and survivability while limiting the physiological costs of consistently high T. Human challenge hypothesis research focuses on young men in industrial populations, who have higher baseline T levels than men in subsistence populations. We tested whether the Tsimane, pathogenically stressed forager-horticulturalists of the Bolivian Amazon, would express acute T increases in response to physical competition. Saliva was collected from 88 Tsimane men (aged 16–59 years) before and after a competitive soccer match. Tsimane men had significantly lower baseline levels of T (
β
= −0.41,
p
< 0.001) when compared with age-matched United States (US) males. Linear mixed-effects models were used to establish that T increased significantly immediately following competition (
β
= 0.23,
p
< 0.001), remaining high 1 h later (
β
= 0.09,
p
= 0.007); equivalent to 30.1 and 15.5 per cent increases in T, respectively. We did not find larger increases in T among winners (
p
= 0.412), although T increases were positively associated with self-rated performance (
β
= 9.07,
p
= 0.004). These results suggest that despite lower levels of T than US males, Tsimane males exhibit acute increases in T at the same relative magnitude reported by studies in industrialized settings, with larger increases in T for those who report better individual performance.
Impact of Mano a Mano‐Mujer, an HIV prevention intervention, on depressive symptoms among Chilean women
Authors: CIANELLI R. , LARA L. , VILLEGAS N. , BERNALES M. , FERRER L. , KAELBER L. , PERAGALLO N.
Published: March 2012

Accessible summary

Depression is considered a factor that interferes with HIV prevention.

Depression may reach 41% among low‐income Chilean women.

The current study analyzed the impact of Mano a Mano‐Mujer, an HIV prevention intervention, on depressive symptoms among low‐income Chilean women.

Mano a Mano‐Mujer provided significant benefits for women's depression symptoms.

Worldwide, and in Chile, the number of women living with HIV is increasing. Depression is considered a factor that interferes with HIV prevention. Depression may reach 41% among low‐income Chilean women. Depressed people are less willing to participate in behaviours that protect them against HIV. The aim of this study is to analyze the impact of Mano a Mano‐Mujer (MM‐M), and HIV prevention intervention, on depressive symptoms among Chilean women. A quasi‐experimental design was used for this study. The research was conducted in Santiago, Chile; a total of 400 women participated in the study (intervention group, n = 182; control group, n = 218). The intervention was guided by the social‐cognitive model and the primary health care model. The intervention consists of six 2‐h sessions delivered in small groups. Sessions covered: HIV prevention, depression, partner's communication, and substance abuse. Face‐to‐face interviews were conducted at baseline and at 3‐month follow‐up. Chilean women who participated in MM‐M significantly decreased, at 3 months follow up, their reported depressive symptoms. MM‐M provided significant benefits for women's depression symptoms. In this study nurses participated as leaders for the screening of depressive symptoms and as facilitators of community interventions.
High‐resolution plant metabolomics: from mass spectral features to metabolites and from whole‐cell analysis to subcellular metabolite distributions
Authors: Kueger Stephan , Steinhauser Dirk , Willmitzer Lothar , Giavalisco Patrick
Published: March 2012

The main goal of metabolomics is the comprehensive qualitative and quantitative analysis of the time‐ and space‐resolved distribution of all metabolites present in a given biological system. Because metabolite structures, in contrast to transcript and protein sequences, are not directly deducible from the genomic DNA sequence, the massive increase in genomic information is only indirectly of use to metabolomics, leaving compound annotation as a key problem to be solved by the available analytical techniques. Furthermore, as metabolites vary widely in both concentration and chemical behavior, there is no single analytical procedure allowing the unbiased and comprehensive structural elucidation and determination of all metabolites present in a given biological system. In this review the different approaches for targeted and non‐targeted metabolomics analysis will be described with special emphasis on mass spectrometry‐based techniques. Particular attention is given to approaches which can be employed for the annotation of unknown compounds. In the second part, the different experimental approaches aimed at tissue‐specific or subcellular analysis of metabolites are discussed including a range of non‐mass spectrometry based technologies.
Hydrallantois in the Mare – A Report of Five Cases
Authors: Govaere JLJ , De Schauwer C , Hoogewijs MK , Chiers K , Lefère L , Catry B , Roels K , van Heerden M , Broeckx S , de Kruif A
Published: March 2012

Contents

Hydrallantois in the mare is a very rare condition, and clinical reports help to gather information to elucidate its pathogenesis, treatment options and prognosis. Five different cases of hydrallantois in the mare are reported in this article, all with the involvement of placentitis. The five mares were presented because of acute distention of the abdomen, dyspnoea, stiff gait and a lack of appetite. After a gradual release of the excessive amount of allantoic fluid, an abortion was induced in all five mares. The foals were either born dead or euthanized. The mares recovered quickly. One mare conceived within the same season, one remained barren despite several cycles of natural breeding, and no data were available on the other three mares. In this series, the condition is reported for the first time in two Shetland ponies, both pregnant with foals sharing a close genetic background. In both cases, the condition led to hyperlipidemia. The condition as it occurs in nulliparous mares is also discussed. Finally, the possible involvement of placentitis in the pathogenesis is emphasized.
A review of the opportunities and challenges facing the nursing associations in Iran
Authors: Esmaeili M. , Dehghan‐Nayeri N. , Negarandeh R.
Published: March 2012

ESMAEILI M., DEHGHAN‐NAYERI N. & NEGARANDEH R. (2012) A review of the opportunities and challenges facing the nursing associations in Iran. International Nursing Review59, 168–174

Background:  Nursing associations and organizations are deemed to be effective tools in promoting the profession. Professional nursing associations are an essential part of the nursing culture. Examining the challenges and opportunities confronting the associations would pave the way for the identification of their limitations and also would lead to more interactions among the members and the associations.

Methods:  Following an extensive review of the literature and also examining the professional nursing associations in Iran, the common challenges facing the nursing associations are identified and their shared challenges with other associations in other countries have been explored. Lack of members and insufficient support from the associations, financial problems, non‐professional activities of associations and lack of interactions among associations are among the important challenges that the nursing associations confront within Iran. The possibility for establishing specialized nursing associations for increasing teamwork activities can be pointed out as one of the available opportunities.

Conclusion:  Professional associations follow important priorities with regard to their objectives, which distinguishes each from the other. The clear introduction of objectives and pinpointing the convergences that might bring about clashes between them will lead to building confidence among nurses, and hopefully, increasing membership. Members' dynamic participation, and support and interactions between associations are among the measures for increasing the professional power. Researchers hope that this article could provide both nurses and professional associations with insights to support each other for the purpose of promoting professional development. Considering the insufficient research in the field, more studies are also suggested.
The Adaptative Nature of Neoliberalism at the Local Scale: Fifteen Years of City Improvement Districts in Cape Town and Johannesburg
Authors: Didier Sophie , Morange Marianne , Peyroux Elisabeth
Published: March 2012

Abstract:  By unravelling the adoption and adaptation of the North American Business Improvement District (BID) model in South African cities, this paper considers the way neoliberal principles are making their way in the post‐apartheid context. Drawing on a comparative approach of BIDs in Johannesburg and Cape Town, we analyse the tensions and conflicts surrounding their implementation and unpack the resilience of this model. As unexpected as this resilience might be in such a context, that is, far away from the heartland of neoliberalism, we argue that this resilience is linked to the permeability of the local contexts and to the plasticity of the model itself at the city and neighbourhood levels, reflecting a capacity to adapt to inherited regulatory frameworks, patterns of territorial development and embedded socio‐political alliances of the local terrains, as well as an ability to accommodate post‐apartheid issues through the crafting of what we refer to as “local Third Ways”.
Should Chinese Renminbi be Blamed for Its Trade Surplus? A Structural VAR Approach
Authors: Zhang Zhaoyong , Sato Kiyotaka
Published: March 2012

During the recent years, the Renminbi (RMB) exchange rate issue has been at the centre of ongoing debate over the source of global current account imbalance, especially with the United States. The objective of this study is to contribute to the current discussion by providing some new evidence on China’s exchange rate policy and the impacts of RMB devaluation/revaluation on China’s trade balance using a structural vector autoregression (VAR) approach. The results indicate that the dynamic effect of exchange rate on China’s trade balance is still very limited and China’s balance of trade is mainly determined by the world demand and its trade performance, with the latter being a result of its successfully maintained comparative advantage.