bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoproduction of Pion Pairs at Moderate Energies
Authors: Chandramohan T , Venkatesan K , Achuthan P
Published: June 2011

The problem of the production of pion pairs in photon-nucleon collisions is studied with the help of a new Lagrangian model. Using a relativistic covariant and gauge-invariant scattering amplitude based on a phenomenological Lagrangian, the differential and total cross sections are calculated for unpolarized and linearly polarized photons. The production amplitude incorporates terms involving 8(700), p(770), f(1260) and A(1236) resonances in addition to the nucleon and pion exchanges.
Gamma Rays from keV Neutron Capture in Lanthanum
Authors: Kenny MJ , Allen BJ
Published: June 2011

A Ge(Li) detector has been used to observe )I-ray transitions after the capture of keV neutrons in lanthanum. An analysis of nonstatistical transitions to low-lying In = 3 final states supports the proposed particle-hole capture mechanism.
Resonant Neutron Capture in 139La
Authors: de L Musgrove AR , Allen BJ , Macklin RL
Published: June 2011

The neutron capture cross section of 139La has been measured with high energy resolution between 2� 5 and 90 ke V using the capture cross section facility at the 40 m station on the Oak Ridge Electron Linear Accelerator. Individual resonances were analysed to 15 keV and the average s- and p-wave radiative widths deduced were <Γγ>s = 55�6meV and <Γγ>p = 4O�7meV. The p-wave neutron strength function obtained was S1 = (0'30�0'1O)x 10-4 ? The s-wave resonances decay strongly to final f-wave states via a postulated doorway state mechanism. The transition strengths for these decays are not correlated with the neutron widths of the initial states.
A Note on the Abraham?Lorentz Equation
Authors: L Murphy George
Published: June 2011

A generalization of the usual nonrelativistic energy integral is found for the Abraham-Lorentz equation with a constant external force term.
Australian Journal of Physics Astrophysical Supplements
Authors: Hazard C , Murdoch HS
Published: June 2011

This paper presents the results of an examination of the fields around 350 sources in the Molonglo radio source catalogues MC2 and MC3 for the R.A. interval 11 h 28m to 17h oom. The 300 sources with a flux density ;;. 0�45 Jy form an essentially complete radio sample and of these 21 % are identified with BSOs (most of which have now been spectroscopically confirmed as QSOs) and 22 % with galaxies of Ism or brighter. The magnitude scales adopted are carefully defined and based on the spectral sensitivity of the Palomar Sky Survey plates. A brief discussion is given of the magnitude distribution of the BSO identifications and possible evidence for anisotropy in the QSO distribution is noted.
Clofarabine 5′-di and -triphosphates inhibit human ribonucleotide reductase by altering the quaternary structure of its large subunit
Authors: Aye Yimon , Stubbe JoAnne
Published: June 2011

Human ribonucleotide reductases (hRNRs) catalyze the conversion of nucleotides to deoxynucleotides and are composed of α- and β-subunits that form activeαnβm(n,m = 2 or 6) complexes. α binds NDP substrates (CDP, UDP, ADP, and GDP, C site) as well as ATP and dNTPs (dATP, dGTP, TTP) allosteric effectors that control enzyme activity (A site) and substrate specificity (S site). Clofarabine (ClF), an adenosine analog, is used in the treatment of refractory leukemias. Its mode of cytotoxicity is thought to be associated in part with the triphosphate functioning as an allosteric inhibitor of hRNR. Studies on the mechanism of inhibition of hRNR by ClF di- and triphosphates (ClFDP and ClFTP) are presented. ClFTP is a reversible inhibitor (Ki = 40 nM) that rapidly inactivates hRNR. However, with time, 50% of the activity is recovered. D57N-α, a mutant with an altered A site, prevents inhibition by ClFTP, suggesting its A site binding. ClFDP is a slow-binding, reversible inhibitor (;t1/2 = 23 min). CDP protects α from its inhibition. The altered off-rate of ClFDP from E•ClFDP∗by ClFTP (A site) or dGTP (S site) and its inhibition of D57N-α together implicate its C site binding. Size exclusion chromatography of hRNR or α alone with ClFDP or ClFTP, ± ATP or dGTP, reveals in each case that α forms a kinetically stable hexameric state. This is the first example of hexamerization of α induced by an NDP analog that reversibly binds at the active site.
Tropical amphibian populations experience higher disease risk in natural habitats
Authors: Becker C. Guilherme , Zamudio Kelly R.
Published: June 2011

Habitat loss and disease are main drivers of global amphibian declines, yet the interaction between them remains largely unexplored. Here we show that paradoxically, habitat loss is negatively associated with occurrence, prevalence, and infection intensity of the chytrid fungus
Batrachochytrium dendrobatidis
(
Bd
) in amphibian populations in the tropics. At a large spatial scale, increased habitat loss predicted lower disease risk in amphibian populations across Costa Rica and eastern Australia, even after jointly considering the effect of potential biotic and abiotic correlates. Lower host-species richness and suboptimal microclimates for
Bd
in disturbed habitats are potential mechanisms underlying this pattern. Furthermore, we found that anthropogenic deforestation practices biased to lowlands and natural vegetation remaining in inaccessible highlands explain increased
Bd
occurrence at higher elevations. At a smaller spatial scale, holding constant elevation, latitude, and macroclimate, we also found a negative relationship between habitat loss, and both
Bd
prevalence and infection intensity in frog populations in two landscapes of the Brazilian Atlantic Forest. Our results indicate that amphibians will be disproportionately affected by emerging diseases in pristine environments, and that, paradoxically, disturbed habitats may act as shelters from disease, but only for the very few species that can tolerate deforestation. Thus, tropical amphibian faunas are threatened both by destruction of natural habitats as well as increased disease in pristine forests. To curb further extinctions and develop effective mitigation and restoration programs we must look to interactions between habitat loss and disease, the two main factors at the root of global amphibian declines.
The trans-Himalayan flights of bar-headed geese (
Anser indicus
)
Authors: Hawkes Lucy A. , Balachandran Sivananinthaperumal , Batbayar Nyambayar , Butler Patrick J. , Frappell Peter B. , Milsom William K. , Tseveenmyadag Natsagdorj , Newman Scott H. , Scott Graham R. , Sathiyaselvam Ponnusamy , Takekawa John Y. , Wikelski Martin , Bishop Charles M.
Published: June 2011

Birds that fly over mountain barriers must be capable of meeting the increased energetic cost of climbing in low-density air, even though less oxygen may be available to support their metabolism. This challenge is magnified by the reduction in maximum sustained climbing rates in large birds. Bar-headed geese (
Anser indicus
) make one of the highest and most iconic transmountain migrations in the world. We show that those populations of geese that winter at sea level in India are capable of passing over the Himalayas in 1 d, typically climbing between 4,000 and 6,000 m in 7–8 h. Surprisingly, these birds do not rely on the assistance of upslope tailwinds that usually occur during the day and can support minimum climb rates of 0.8–2.2 km·h
−1
, even in the relative stillness of the night. They appear to strategically avoid higher speed winds during the afternoon, thus maximizing safety and control during flight. It would seem, therefore, that bar-headed geese are capable of sustained climbing flight over the passes of the Himalaya under their own aerobic power.
Drosophilahomeodomain-interacting protein kinase inhibits the Skp1-Cul1-F-box E3 ligase complex to dually promote Wingless and Hedgehog signaling
Authors: Swarup Sharan , Verheyen Esther M.
Published: June 2011

DrosophilaHomeodomain-interacting protein kinase (Hipk) has been shown to regulate in vivo, the stability of Armadillo, the transcriptional effector of Wingless signaling. The Wingless pathway culminates in the stabilization of Armadillo that, in the absence of signaling, is sequentially phosphorylated, polyubiquitinated and degraded. Loss-of-function clones forhipkresult in reduced stabilized Armadillo, whereas overexpression ofhipkelevates Armadillo levels to promote Wingless-responsive target gene expression. Here, we show that overexpression ofhipkcan suppress the effects of negative regulators of Armadillo to prevent its degradation in the wing imaginal disc. Hipk acts to stabilize Armadillo by impeding the function of the E3 ubiquitin ligase Skp1-Cul1-F-box (SCF)Slimb, thereby inhibiting Armadillo ubiquitination and subsequent degradation. Vertebrate Hipk2 displays a similar ability to prevent β-catenin ubiquitination in a functionally conserved mechanism. We find that Hipk's ability to inhibit SCFSlimb-mediated ubiquitination is not restricted to Armadillo and extends to other substrates of SCFSlimb, including the Hedgehog signaling effector Ci. Thus, similar to casein kinase 1 and glycogen synthase kinase 3, Hipk dually regulates both Wingless and Hedgehog signaling by controlling the stability of their respective signaling effectors, but it is the first kinase to our knowledge identified that promotes the stability of both Armadillo and Ci.
Enhancement of CA3 hippocampal network activity by activation of group II metabotropic glutamate receptors
Authors: Ster Jeanne , Mateos José María , Grewe Benjamin Friedrich , Coiret Guyllaume , Corti Corrado , Corsi Mauro , Helmchen Fritjof , Gerber Urs
Published: June 2011

Impaired function or expression of group II metabotropic glutamate receptors (mGluRIIs) is observed in brain disorders such as schizophrenia. This class of receptor is thought to modulate activity of neuronal circuits primarily by inhibiting neurotransmitter release. Here, we characterize a postsynaptic excitatory response mediated by somato-dendritic mGluRIIs in hippocampal CA3 pyramidal cells and in stratum oriens interneurons. The specific mGluRII agonists DCG-IV or LCCG-1 induced an inward current blocked by the mGluRII antagonist LY341495. Experiments with transgenic mice revealed a significant reduction of the inward current in mGluR3−/−but not in mGluR2−/−mice. The excitatory response was associated with periods of synchronized activity at theta frequency. Furthermore, cholinergically induced network oscillations exhibited decreased frequency when mGluRIIs were blocked. Thus, our data indicate that hippocampal responses are modulated not only by presynaptic mGluRIIs that reduce glutamate release but also by postsynaptic mGluRIIs that depolarize neurons and enhance CA3 network activity.
In vivo diagnosis of murine pancreatic intraepithelial neoplasia and early-stage pancreatic cancer by molecular imaging
Authors: Eser Stefan , Messer Marlena , Eser Philipp , von Werder Alexander , Seidler Barbara , Bajbouj Monther , Vogelmann Roger , Meining Alexander , von Burstin Johannes , Algül Hana , Pagel Philipp , Schnieke Angelika E. , Esposito Irene , Schmid Roland M. , Schneider Günter , Saur Dieter
Published: June 2011

Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease with poor patient outcome often resulting from late diagnosis in advanced stages. To date methods to diagnose early-stage PDAC are limited and in vivo detection of pancreatic intraepithelial neoplasia (PanIN), a preinvasive precursor of PDAC, is impossible. Using a cathepsin-activatable near-infrared probe in combination with flexible confocal fluorescence lasermicroscopy (CFL) in a genetically defined mouse model of PDAC we were able to detect and grade murine PanIN lesions in real time in vivo. Our diagnostic approach is highly sensitive and specific and proved superior to clinically established fluorescein-enhanced imaging. Translation of this endoscopic technique into the clinic should tremendously improve detection of pancreatic neoplasia, thus reforming management of patients at risk for PDAC.
Protein-specific manipulation of ejaculate composition in response to female mating status in
Drosophila melanogaster
Authors: Sirot Laura K. , Wolfner Mariana F. , Wigby Stuart
Published: June 2011

Female promiscuity can generate postcopulatory competition among males, but it also provides the opportunity for exploitation of rival male ejaculates. For example, in many insect species, male seminal fluid proteins (Sfps) transferred in a female's first mating stimulate increased fecundity and decreased receptivity to remating. Subsequent mates of females could potentially take advantage of the effects of the first male's Sfps and strategically reduce investment in their own ejaculate. We compared postmating responses (fecundity and sexual receptivity) of
Drosophila melanogaster
females after their first (virgin) matings (V), to the responses of females remating (M) 24 h after their first mating. The results show that M matings fail to boost fecundity and, thus, males are unlikely to gain fitness from transferring Sfps whose sole function—in V matings—is fecundity-stimulation. However, males can protect their likelihood of paternity in M matings through the transfer of receptivity-inhibiting Sfps. The levels of a fecundity-stimulating Sfp (ovulin) were significantly lower in M females relative to V females, at the same time point shortly after the end of mating. In contrast, the levels of a key receptivity-inhibiting Sfp (sex peptide) were the same in M and V females. These results support the hypothesis that males can adaptively tailor the composition of proteins in the ejaculate, allowing a male to take advantage of the fecundity-stimulating effects of the previous male's ovulin, yet maintaining investment in sex peptide. Furthermore, our results demonstrate sophisticated protein-specific ejaculate manipulation.
Postsynaptic P/Q-type Ca
2+
channel in Purkinje cell mediates synaptic competition and elimination in developing cerebellum
Authors: Hashimoto Kouichi , Tsujita Mika , Miyazaki Taisuke , Kitamura Kazuo , Yamazaki Maya , Shin Hee-Sup , Watanabe Masahiko , Sakimura Kenji , Kano Masanobu
Published: June 2011

Neural circuits are initially redundant but rearranged through activity-dependent synapse elimination during postnatal development. This process is crucial for shaping mature neural circuits and for proper brain function. At birth, Purkinje cells (PCs) in the cerebellum are innervated by multiple climbing fibers (CFs) with similar synaptic strengths. During postnatal development, a single CF is selectively strengthened in each PC through synaptic competition, the strengthened single CF undergoes translocation to a PC dendrite, and massive elimination of redundant CF synapses follows. To investigate the cellular mechanisms of this activity-dependent synaptic refinement, we generated mice with PC-selective deletion of the Ca
v
2.1 P/Q-type Ca
2+
channel, the major voltage-dependent Ca
2+
channel in PCs. In the PC-selective Ca
v
2.1 knockout mice, Ca
2+
transients induced by spontaneous CF inputs are markedly reduced in PCs in vivo. Not a single but multiple CFs were equally strengthened in each PC from postnatal day 5 (P5) to P8, multiple CFs underwent translocation to PC dendrites, and subsequent synapse elimination until around P12 was severely impaired. Thus, P/Q-type Ca
2+
channels in postsynaptic PCs mediate synaptic competition among multiple CFs and trigger synapse elimination in developing cerebellum.
Approach to discover T- and B-cell antigens of intracellular pathogens applied to the design of
Chlamydia trachomatis
vaccines
Authors: Finco Oretta , Frigimelica Elisabetta , Buricchi Francesca , Petracca Roberto , Galli Giuliano , Faenzi Elisa , Meoni Eva , Bonci Alessandra , Agnusdei Mauro , Nardelli Filomena , Bartolini Erika , Scarselli Maria , Caproni Elena , Laera Donatello , Zedda Luisanna , Skibinski David , Giovinazzi Serena , Bastone Riccardo , Ianni Elvira , Cevenini Roberto , Grandi Guido , Grifantini Renata
Published: June 2011

Natural immunity against obligate and/or facultative intracellular pathogens is usually mediated by both humoral and cellular immunity. The identification of those antigens stimulating both arms of the immune system is instrumental for vaccine discovery. Although high-throughput technologies have been applied for the discovery of antibody-inducing antigens, few examples of their application for T-cell antigens have been reported. We describe how the compilation of the immunome, here defined as the pool of immunogenic antigens inducing T- and B-cell responses in vivo, can lead to vaccine candidates against
Chlamydia trachomatis
. We selected 120
C. trachomatis
proteins and assessed their immunogenicity using two parallel high-throughput approaches. Protein arrays were generated and screened with sera from
C. trachomatis
-infected patients to identify antibody-inducing antigens. Splenocytes from
C. trachomatis
-infected mice were stimulated with 79 proteins, and the frequency of antigen-specific CD4
+
/IFN-γ
+
T cells was analyzed by flow cytometry. We identified 21 antibody-inducing antigens, 16 CD4
+
/IFN-γ
+
–inducing antigens, and five antigens eliciting both types of responses. Assessment of their protective activity in a mouse model of
Chlamydia muridarum
lung infection led to the identification of seven antigens conferring partial protection when administered with LTK63/CpG adjuvant. Protection was largely the result of cellular immunity as assessed by CD4
+
T-cell depletion. The seven antigens provided robust additive protection when combined in four-antigen combinations. This study paves the way for the development of an effective anti-
Chlamydia
vaccine and provides a general approach for the discovery of vaccines against other intracellular pathogens.
Elucidating glycosaminoglycan–protein–protein interactions using carbohydrate microarray and computational approaches
Authors: Rogers Claude J. , Clark Peter M. , Tully Sarah E. , Abrol Ravinder , Garcia K. Christopher , Goddard William A. , Hsieh-Wilson Linda C.
Published: June 2011

Glycosaminoglycan polysaccharides play critical roles in many cellular processes, ranging from viral invasion and angiogenesis to spinal cord injury. Their diverse biological activities are derived from an ability to regulate a remarkable number of proteins. However, few methods exist for the rapid identification of glycosaminoglycan–protein interactions and for studying the potential of glycosaminoglycans to assemble multimeric protein complexes. Here, we report a multidisciplinary approach that combines new carbohydrate microarray and computational modeling methodologies to elucidate glycosaminoglycan–protein interactions. The approach was validated through the study of known protein partners for heparan and chondroitin sulfate, including fibroblast growth factor 2 (FGF2) and its receptor FGFR1, the malarial protein VAR2CSA, and tumor necrosis factor-α (TNF-α). We also applied the approach to identify previously undescribed interactions between a specific sulfated epitope on chondroitin sulfate, CS-E, and the neurotrophins, a critical family of growth factors involved in the development, maintenance, and survival of the vertebrate nervous system. Our studies show for the first time that CS is capable of assembling multimeric signaling complexes and modulating neurotrophin signaling pathways. In addition, we identify a contiguous CS-E-binding site by computational modeling that suggests a potential mechanism to explain how CS may promote neurotrophin-tyrosine receptor kinase (Trk) complex formation and neurotrophin signaling. Together, our combined microarray and computational modeling methodologies provide a general, facile means to identify new glycosaminoglycan–protein–protein interactions, as well as a molecular-level understanding of those complexes.
Unusual regioversatility of acetyltransferase Eis, a cause of drug resistance in XDR-TB
Authors: Chen Wenjing , Biswas Tapan , Porter Vanessa R. , Tsodikov Oleg V. , Garneau-Tsodikova Sylvie
Published: June 2011

The emergence of multidrug-resistant and extensively drug-resistant (XDR) tuberculosis (TB) is a serious global threat. Aminoglycoside antibiotics are used as a last resort to treat XDR-TB. Resistance to the aminoglycoside kanamycin is a hallmark of XDR-TB. Here, we reveal the function and structure of the mycobacterial protein Eis responsible for resistance to kanamycin in a significant fraction of kanamycin-resistant
Mycobacterium tuberculosis
clinical isolates. We demonstrate that Eis has an unprecedented ability to acetylate multiple amines of many aminoglycosides. Structural and mutagenesis studies of Eis indicate that its acetylation mechanism is enabled by a complex tripartite fold that includes two general control non-derepressible 5 (GCN5)-related
N
-acetyltransferase regions. An intricate negatively charged substrate-binding pocket of Eis is a potential target of new antitubercular drugs expected to overcome aminoglycoside resistance.
Proliferating cell nuclear antigen (PCNA)-associated KIAA0101/PAF15 protein is a cell cycle-regulated anaphase-promoting complex/cyclosome substrate
Authors: Emanuele Michael J. , Ciccia Alberto , Elia Andrew E. H. , Elledge Stephen J.
Published: June 2011

The anaphase-promoting complex/cyclosome (APC/C) is a cell cycle-regulated E3 ubiquitin ligase that controls the degradation of substrate proteins at mitotic exit and throughout the G1 phase. We have identified an APC/C substrate and cell cycle-regulated protein, KIAA0101/PAF15. PAF15 protein levels peak in the G2/M phase of the cell cycle and drop rapidly at mitotic exit in an APC/C- and KEN-box–dependent fashion. PAF15 associates with proliferating cell nuclear antigen (PCNA), and depletion of PAF15 decreases the number of cells in S phase, suggesting a role for it in cell cycle regulation. Following irradiation, PAF15 colocalized with γH2AX foci at sites of DNA damage through its interaction with PCNA. Finally, PAF15 depletion led to an increase in homologous recombination-mediated DNA repair, and overexpression caused sensitivity to UV-induced DNA damage. We conclude that PAF15 is an APC/C-regulated protein involved in both cell cycle progression and the DNA damage response.
Circadian clock disruption improves the efficacy of chemotherapy through p73-mediated apoptosis
Authors: Lee Jin Hyup , Sancar Aziz
Published: June 2011

The circadian clock in mammalian organisms is generated by a transcription–translation feedback loop that controls many biochemical pathways at the cellular level and physiology and behavior at the organismal level. Cryptochrome (Cry) is a key protein in the negative arm of the transcription–translation feedback loop. It has been found that Cry mutation in cells with p53-null genotype increased their sensitivity to apoptosis by genotoxic agents. Here we show that this increased sensitivity is due to up-regulation of the p53 gene family member p73 in response to DNA damage. As a consequence, when tumors arising from oncogenic Ras-transformed

p53
−/−

and

p53
−/−
Cry1
−/−
Cry2
−/−

cells are treated with the anticancer drug oxaliplatin,

p53
−/−

tumors continue to grow whereas

p53
−/−
Cry1
−/−
Cry2
−/−

tumors exhibit extensive apoptosis and stop growing. This finding provides a mechanistic foundation for overcoming the resistance of p53-deficient tumor cells to apoptosis induced by DNA-damaging agents and suggests that disruption of cryptochrome function may increase the sensitivity of tumors with p53 mutation to chemotherapy.
Pathway-specific engagement of ephrinA5-EphA4/EphA5 system of the substantia nigra pars reticulata in cocaine-induced responses
Authors: Kimura Kensuke , Hikida Takatoshi , Yawata Satoshi , Yamaguchi Takashi , Nakanishi Shigetada
Published: June 2011

The nucleus accumbens (NAc) serves as a key neural substrate that controls acute and adaptive behavioral responses to cocaine administration. In this circuit, inputs from the NAc are transmitted through two parallel pathways, named the direct and indirect pathways, and converge at the substantia nigra pars reticulata (SNr). Our previous study using reversible neurotransmission blocking (RNB) of each pathway revealed that the dual stimulation of the SNr by both pathways is necessary for the acute response, but that the direct pathway predominantly controls the adaptive response to repeated cocaine administration. This study aimed at exploring the pathway-specific mechanism of cocaine actions at the convergent SNr. We examined a genome-wide expression profile of the SNr of three types of experimental mice: the direct pathway-blocked D-RNB mice, the indirect pathway-blocked I-RNB mice, and wild-type mice. We identified the up-regulation of ephrinA5, EphA4, and EphA5 specific to D-RNB mice during both acute and adaptive responses to cocaine administration. The activation by EphA4 and EphA5 in the SNr of wild-type mice by use of the immunoadhesin technique suppressed the adaptive response to repeated cocaine administration. Furthermore, cocaine exposure stimulated the phosphorylation of Erk1/2 in ephrinA5-expressing SNr cells in a direct pathway-dependent manner. The results have demonstrated that the ephrinA5-EphA4/EphA5 system plays an important role in the direct pathway-dependent regulation of the SNr in both acute and adaptive cocaine responses and would provide valuable therapeutic targets of cocaine addiction.
The Use of Message Framing in the Promotion of Environmentally Sustainable Behaviors
Authors: Cheng Tania , Woon Danielle Kathryn , Lynes Jennifer K.
Published: June 2011

The use of message framing, a technique that shapes perceptions of the outcomes of the promoted behavior, in combination with a specific target audience can substantially enhance the success of social marketing campaigns. Although the persuasive effects of message framing have been widely publicized in the field of social and cognitive psychology, there is a surprising dearth in the literature regarding the role of message framing as a strategy within the context of social marketing to influence environmentally sustainable behaviors. This article provides an overview of the main principles of message framing, including gain and loss framing as well as social and physical threat. The most effective combination of frame and threat may in fact depend on the measure used to assess its influence on behavior. In particular, the literature suggests that the effect of frame and threat interaction may be most prominent in changing attitudes toward the behavior. Four factors should be considered in the use of framing and threat in message design, including: (1) level of risk involved in uptake of the behaviour, (2) degree of self-referencing or self-other referencing in the message, (3) level of experience and knowledge of the target audience and stage of change of the target audience, and (4) gender of target audience. Thus, proper segmentation of the population should be carried out before designing messages with frame/threat factors. Further research on the influence of message framing and the role of audience segmentation in behavioral change strategies is needed to deepen our understanding of its effectiveness in designing social marketing campaigns that focus on environmentally sustainable behaviors.
Stop Bullying Now! Campaign Pilot Evaluation: A Qualitative Assessment of its Usefulness and Cultural Appropriateness for Hispanic Populations
Authors: Saladin-Subero Rosanna , Hawkins Katherine
Published: June 2011

The Stop Bullying Now! (SBN!) campaign is a media-based national effort launched in 2004. Developed by the Health Resources and Services Administration (HRSA) of the U.S. Department of Health and Human Services, its purpose was to raise awareness about bullying, preventing and reducing bullying behaviors, identifying appropriate interventions for tweens, and fostering linkages among partners' organizations. The campaign targets youths aged 9 through 13 and those who influence them (e.g., family members; educators; law enforcement; and health, safety, and mental health professionals). This pilot study was the first effort to evaluate the national campaign with Hispanics. Focus groups with mothers, one-on-one interviews with fathers, and in-depth interviews with tutors were held. The findings suggested that, despite minor formatting issues, the materials used in the SBN! campaign appeared to be appropriate for use with Hispanic parents. The study also suggested that the campaign may not have been effective in reaching Hispanic parents living in the two towns sampled, as the parents involved had a low level of knowledge of what bullying was, did not know of the SBN! campaign, and had not seen the materials created for the campaign.
Implementation of the critical points model in a SFM-FDTD code working in oblique incidence
Authors: Hamidi M , Baida F I , Belkhir A , Lamrous O
Published: June 2011

We describe the implementation of the critical points model in a finite-difference-time-domain code working in oblique incidence and dealing with dispersive media through the split field method. Some tests are presented to validate our code in addition to an application devoted to plasmon resonance of a gold nanoparticles grating.
Effect of Al3+ substitution on the transport properties of copper ferrite
Authors: Lakhani V K , Modi K B
Published: June 2011

This study presents the compositional and the temperature-dependent thermoelectric power and dc resistivity measurements on polycrystalline spinel ferrite system: CuAl
x
Fe2−x
O4 (x = 0.0, 0.2, 0.4 and 0.6). The probable conduction mechanisms in the system are Fe2+ ↔ Fe3+ + e− (n-type) at the octahedral sites and Cu2+ ↔ Cu1+ + e+ (p-type) at the tetrahedral sites. The cationic concentrations of Cu1+, Cu2+, ferrous and ferric ions have been deduced from Seebeck coefficients which, in turn, are used to determine the actual cation distribution, oxygen deficiency and to explain the variation and origin of dc resistivity with Al concentration. The Fermi energy, charge carrier concentration and mobility of charge carrier have been determined to explain the charge transport phenomena.
Large-scale synthesis of hydrophobic SiC/C nanocables with enhanced electrical properties
Authors: Wang Xiuchun , Tang Bin , Gao Fengmei , Zheng Jinju , Wei Guodong , Yang Weiyou
Published: June 2011

Inhibiting the easy oxidation nature of SiC nanostructure surface is a challenge for its application in nanodevices. Here, we have demonstrated the fabrication of C-sheathed SiC nanocables via a designed chemical vapour deposition method, in which the use of a steel-hoop-like sample support favours the growth of SiC/C nanocables with surface modification of C coatings. The obtained SiC/C nanocables are systematically characterized by scanning electron microscopy, x-ray diffraction, transmission electron microscopy and Raman spectroscopy. The electrical property measurements suggest that the surface modification of SiC nanostructures by C coatings can not only modulate the SiC surface property from hydrophilic to hydrophobic, but also significantly enhance their electrical properties.
Steady-state operation in compact tokamaks with copper coils
Authors: Kuteev B.V. , Azizov E.A. , Bykov A.S. , Dnestrovsky A.Yu. , Dokuka V.N. , Gladush G.G. , Golikov A.A. , Goncharov P.R. , Gryaznevich M. , Gurevich M.I. , Ivanov A.A. , Khairutdinov R.R. , Khripunov V.I. , Kingham D. , Klishchenko A.V. , Kurnaev V.A. , Lukash V.E. , Medvedev S.Yu. , Savrukhin P.V. , Sergeev V.Yu. , Shpansky Yu.S. , Sykes A. , Voss G. , Zhirkin A.V.
Published: June 2011

This paper considers a fast track to non-energy applications of nuclear fusion that is associated with the ‘fusion for neutrons’ (F4N) paradigm. Being a useful product accompanying energy, fusion neutrons are more valuable than the energy released in DT reactions and they are urgently needed for research purposes and to develop and validate modern technologies. In the near future neutron yield in fusion devices will become significantly larger than that of fission and accelerator sources. This paper describes a compact tokamak fusion neutron source based on a small spherical tokamak (FNS-ST) with a MW range of DT fusion power and considers the key physics issues of this device. The major and minor radii are ∼0.5 and ∼0.3 m with magnetic field ∼1.5 T, heating power less than 15 MW and plasma current 1–2 MA. The production rate of DT neutrons of (3–10) × 1017 n s−1 and their flux at the first wall of 0.2 MW m−2 ensure that the device is capable of fusion–fission demonstration experiments. The problems of major concern are discharge initiation, current drive, plasma—fast ion beam stability and high first wall and divertor loads. The conceptual design provides solutions to these problems and suggests the feasibility of the FNS-ST.
Effect of core pressure gradient just inside the top of the pedestal on the energy loss due to the edge localized mode in JT-60U
Authors: Hayashi N. , Oyama N. , Takizuka T. , Aiba N. , Ozeki T.
Published: June 2011

The effect of core pressure gradient just inside the top of the pedestal on the energy loss due to type-I edge localized modes (ELMs) is studied. An analysis of the experimental data from JT-60U shows that the ELM energy loss normalized by the pedestal stored energy increases with the pressure gradient inside the top of the pedestal normalized by the pedestal pressure gradient. The dependence of normalized ELM energy loss on the normalized pressure gradient inside the top of the pedestal is similar to that predicted by the integrated code TOPICS-IB. The stability of linear ideal MHD modes is analysed using experimental profiles. It is found that the steep core pressure gradient inside the top of the pedestal broadens the eigenfunction profiles of unstable modes inwards. The TOPICS-IB simulation predicted that this broadening can enhance the ELM energy loss.
The impact of 3D fields on tearing mode stability of H-modes
Authors: Buttery R.J. , Gerhardt S. , La Haye R.J. , Liu Y.Q. , Reimerdes H. , Sabbagh S. , Chu M.S. , Osborne T.H. , Park J.-K. , Pinsker R.I. , Strait E.J. , Yu J.H.
Published: June 2011

New processes have been discovered in the interaction of 3D fields with tearing mode stability at low torque and modest β on DIII-D and NSTX. These are thought to arise from the plasma response at the tearing resonant surface, which theoretically is expected to depend strongly on plasma rotation and underlying intrinsic tearing stability. This leads to sensitivities additional to those previously identified at low density where the plasma rotation is more readily stopped, or at high βN where ideal MHD responses amplify the fields (where βN is the plasma β divided by the ratio of plasma current to minor radius multiplied by toroidal field). It is found that the threshold size for 3D fields to induce modes tends to zero as the natural tearing βN limit is approached. 3D field sensitivity is further enhanced at low rotation, with magnetic probing detecting an increased response to applied fields in such regimes. Modelling with the MARS-F code confirms the interpretation with the usual plasma screening response breaking down in low rotation plasmas and a tearing response developing, opening the door to additional sensitivities to β and the current profile. Typical field thresholds to induce modes in torque-free βN ∼ 1.5 H-modes are well below those in ohmic plasmas or plasmas near the ideal βN limit. The strong interaction with the tearing mode βN limit is identified through rotation shear, which is decreased by the 3D field, leading to decreased tearing stability. Thus both locked and rotating mode field thresholds can be considered in terms of a torque balance, with sufficient braking leading to destabilization of a mode. On this basis new measurements of the principal parameter scalings for error field threshold have been obtained in torque-free H-modes leading to new predictions for error field sensitivity in ITER. The scalings have similar exponents to ohmic plasmas, but with seven times lower threshold at the ITER baseline βN value of 1.8, and a linear dependence on proximity to the tearing mode βN limit (∼2.2 at zero torque). This reinforces the need to optimize error field correction strategies in ITER, and implement sources to drive plasma rotation.
Gonality and Clifford index of projective curves on ruled surfaces
Authors: Choi Youngook , Kim Seonja
Published: June 2011

Let

X
X

be a smooth curve on a ruled surface

π
:
S
→
C

\pi : S\rightarrow C

. In this paper, we deal with the questions on the gonality and the Clifford index of

X
X

and on the composedness of line bundles on

X
X

with the covering morphism

π

|

X

\pi |_X

. The main theorem shows that if a smooth curve

X
∼
a

C
o

+

b

f

X\sim aC_o +\textbf {b}f

satisfies some conditions on the degree of

b
\bf b

, then a line bundle

L

\mathcal {L}

on

X
X

with

C
l
i
f
f

(

L

)
≤
a
g
(
C
)
−
1

\mathrm {Cliff}(\mathcal {L})\le ag(C)-1

is composed with

π

|

X

\pi |_X

. This implies that a part of the gonality sequence of

X
X

is computed by the gonality sequence of

C
C

as follows:
\[

d
r

(
X
)
=
a

d
r

(
C
)
 
 

 for 

 
r
≤
L
,

d_r (X)=ad_r (C) ~~\mbox { for }~r\le L,

\]
where

L
L

is the length of the gonality sequence of

C
C

.
Increasing B‐type natriuretic peptide levels predict mortality in unselected haemodialysis patients
Authors: Breidthardt Tobias , Kalbermatter Stefan , Socrates Thenral , Noveanu Markus , Klima Theresia , Mebazaa Alexandre , Mueller Christian , Kiss Denes
Published: June 2011

Aims

Cardiac disease is the major cause of death in patients undergoing chronic haemodialysis. Recent studies have found that B‐type natriuretic peptide (BNP) levels accurately reflect the cardiovascular burden of dialysis patients. However, the prognostic potential of BNP measurements in dialysis patients remains unknown.

Methods and results

The study included 113 chronic dialysis patients who were prospectively followed up. Levels of BNP were measured at baseline and every 6 months thereafter. The potential of baseline BNP and annual BNP changes to predict all‐cause and cardiac mortality were assessed as endpoints. Median follow‐up was 735 (354–1459) days; 35 (31%) patients died, 17 (15%) of them from cardiac causes. Baseline BNP levels were similar among survivors and non‐survivors, and failed to predict all‐cause and cardiac death. Cardiac death was preceded by a marked increase in BNP levels. In survivors BNP levels remained stable [median change: +175% (+20–+384%) vs. −14% (−35–+35%) over the 18 months preceding either death or the end of follow‐up, P< 0.001]. Hence, annual BNP changes adequately predicted all‐cause and cardiac death in the subsequent year {AUCall‐cause = 0.70 [SD 0.05, 95% CI (0.60–0.81)]; AUCcardiac = 0.82 [SD 0.04, 95%CI (0.73–0.90)]}. A BNP increase of 40% provided the best cut‐off level. Cox regression analysis confirmed that annual increases over 40% were associated with a seven‐fold increased risk for all‐cause and cardiac death.

Conclusions

Annual BNP increases above 40% predicted all‐cause and cardiac death in the subsequent year. Hence, serially measuring BNP levels may present a novel tool for risk stratification and treatment guidance of end‐stage renal disease patients on chronic dialysis.
Ocean acidification erodes crucial auditory behaviour in a marine fish
Authors: Simpson Stephen D. , Munday Philip L. , Wittenrich Matthew L. , Manassa Rachel , Dixson Danielle L. , Gagliano Monica , Yan Hong Y.
Published: June 2011

Ocean acidification is predicted to affect marine ecosystems in many ways, including modification of fish behaviour. Previous studies have identified effects of CO
2
-enriched conditions on the sensory behaviour of fishes, including the loss of natural responses to odours resulting in ecologically deleterious decisions. Many fishes also rely on hearing for orientation, habitat selection, predator avoidance and communication. We used an auditory choice chamber to study the influence of CO
2
-enriched conditions on directional responses of juvenile clownfish (
Amphiprion percula
) to daytime reef noise. Rearing and test conditions were based on Intergovernmental Panel on Climate Change predictions for the twenty-first century: current-day ambient, 600, 700 and 900 µatm
p
CO
2
. Juveniles from ambient CO
2
-conditions significantly avoided the reef noise, as expected, but this behaviour was absent in juveniles from CO
2
-enriched conditions. This study provides, to our knowledge, the first evidence that ocean acidification affects the auditory response of fishes, with potentially detrimental impacts on early survival.
Basal superoxide as a sex-specific immune constraint
Authors: Tobler Michael , Healey Mo , Wilson Mark , Olsson Mats
Published: June 2011

There is increasing evidence that reactive oxygen species (ROS), a group of unstable and highly reactive chemical molecules, play a key role in regulating and maintaining life-history trade-offs. Upregulation of ROS in association with immune activation is costly because it may result in an imbalance between pro- and antioxidants and, hence, oxidative damage. Previous research aimed at quantifying this cost has mostly focused on changes in the pro-/antioxidant balance subsequent to an immune response. Here, we test the hypothesis that systemic ROS may constrain immune activation. We show that systemic, pre-challenge superoxide (SO) levels are negatively related to the strength of the subsequent immune response towards the mitogen phytohaemagglutinin in male, but not female painted dragon lizards (
Ctenophorus pictus
). We therefore suggest that systemic SO constrains immune activation in painted dragon males. We speculate that this may be due to sex-specific selection pressures on immune investment.
Risk factors associated with mortality from white-nose syndrome among hibernating bat colonies
Authors: Wilder Aryn P. , Frick Winifred F. , Langwig Kate E. , Kunz Thomas H.
Published: June 2011

White-nose syndrome (WNS) is a disease responsible for unprecedented mortality in hibernating bats. First observed in a New York cave in 2006, mortality associated with WNS rapidly appeared in hibernacula across the northeastern United States. We used yearly presence–absence data on WNS-related mortality among hibernating bat colonies in the Northeast to determine factors influencing its spread. We evaluated hazard models to test hypotheses about the association between the timing of mortality and colony-level covariates, such as distance from the first WNS-affected site, colony size, species diversity, species composition and type of hibernaculum (cave or mine). Distance to origin and colony size had the greatest effects on WNS hazard over the range of observations; the type of hibernaculum and species composition had weaker effects. The distance effect showed a temporal decrease in magnitude, consistent with the pattern of an expanding epizootic. Large, cave-dwelling bat colonies with high proportions ofMyotis lucifugusor other species that seek humid microclimates tended to experience early mortality. Our results suggest that the timing of mortality from WNS is largely dependent on colony location, and large colonies tend to be first in an area to experience high mortality associated with WNS.
Memory processing in great apes: the effect of time and sleep
Authors: Martin-Ordas Gema , Call Josep
Published: June 2011

Following encoding, memory remains temporarily vulnerable to disruption. Consolidation refers to offline time-dependent processes that continue after encoding and stabilize, transform or enhance the memory trace. Memory consolidation resulting from sleep has been reported for declarative and non-declarative memories in humans. We first investigated the temporal course of memory retrieval in chimpanzees, bonobos and orangutans. We found that the amount of retrieved information was time dependent: apes' performance degraded after 1 and 2 h, stabilized after 4 h, started to increase after 8 and 12 h and fully recovered after 24 h. Second, we show that although memories during wakefulness were highly vulnerable to interference from events similar to those witnessed during the original encoding event, an intervening period of sleep not only stabilized apes' memories into more permanent ones but also protected them against interference.
Men with elevated testosterone levels show more affiliative behaviours during interactions with women
Authors: van der Meij Leander , Almela Mercedes , Buunk Abraham P. , Fawcett Tim W. , Salvador Alicia
Published: June 2011

Testosterone (T) is thought to play a key role in male–male competition and courtship in many vertebrates, but its precise effects are unclear. We explored whether courtship behaviour in humans is modulated and preceded by changes in T. Pairs of healthy male students first competed in a non-physical contest in which their T levels became elevated. Each participant then had a short, informal interaction with either an unfamiliar man or woman. The sex of the stimulus person did not affect the participants' behaviour overall. However, in interactions with women, those men who had experienced a greater T increase during the contest subsequently showed more interest in the woman, engaged in more self-presentation, smiled more and made more eye contact. No such effects were seen in interactions with other men. This is the first study to provide direct evidence that elevating T during male–male competition is followed by increased affiliative behaviour towards women.
Synchronous attack is advantageous: mixed genotype infections lead to higher infection success in trematode parasites
Authors: Karvonen Anssi , Rellstab Christian , Louhi Katja-Riikka , Jokela Jukka
Published: June 2011

Co-infecting parasite genotypes typically compete for host resources limiting their fitness. The intensity of such competition depends on whether parasites are reproducing in a host, or using it primarily as a transmission vehicle while not multiplying in host tissues (referred to as ‘competition hypothesis’). Alternatively, simultaneous attack and co-infection by several parasite genotypes might facilitate parasite infection because such a diverse attack could present an additional challenge to host immune defence (referred to as ‘facilitation hypothesis’). We tested the competition hypothesis by comparing the production of transmission stages (cercariae) from snails infected with one or two genotypes of the trematode
Diplostomum pseudospathaceum
. We found that cercarial production did not differ between the two groups of snails, suggesting lower per genotype production in double infections, and competition for host resources. Second, we tested the facilitation hypothesis by comparing parasite infection success on fishes (proportion of parasites establishing in the host) using cercariae originating from single-infected snails, double-infected snails and artificial mixtures of the single genotypes. In both cases, we found higher infection success when fishes were challenged with two parasite genotypes instead of one, supporting the facilitation hypothesis. Our results suggest that constraints defining the success of multiple genotype infections in parasites with multiple host life cycles include both between-genotype resource competition in the host and performance of host immune defences against a diverse parasite challenge.