bluuebunny/crossref_metadata_2025 huggingface dataset:
Snowy plover nest site selection, spatial patterning, and temperatures in the Southern High Plains of Texas
Authors: Saalfeld Sarah T. , Conway Warren C. , Haukos David A. , Johnson William P.
Published: May 2012

Snowy plover (Charadrius nivosus) populations have declined throughout their range, in part because of habitat degradation and poor nest success, making information regarding regionally specific nest site selection and spatial patterns important when considering habitat conservation and management guidelines. We determined nest site selection characteristics (n = 180) and examined spatial patterns (n = 215) of snowy plover nests in saline lakes in the Southern High Plains (SHP) of Texas. At 104 nests, we examined the influence of substrate type on nest temperatures and heat mitigation. Snowy plover nests were more likely to be found near an object, on pebble substrate, and with fewer plants than random sites. High use areas were generally located in areas with pebble substrate and on human‐made or natural islands, berms, and peninsulas. Overall, nests placed on pebble substrate had lower temperatures during the day than nests placed on sand substrates. Nest placement on pebble substrate may be valuable to nesting snowy plovers, providing thermal advantages to incubating adults and depressing potentially high nest predation rates. Management guidelines for this region should emphasize the importance of addressing key elements of snowy plover nesting habitat including the presence of pebble substrate and reducing vegetation encroachment. © 2012 The Wildlife Society.
Establishment of a kinetic model for the intramolecular catalyzed hydrolysis of [18F]‐benzylfluoride containing amino acid analogues by linking experimental and DFT studies
Authors: Kersemans Ken , Sablon Nick , Geerlings Paul , Mertens John
Published: May 2012

In an earlier publication, we suggested that the faster radiodefluorination kinetics of no‐carrier‐added (S)‐3‐(2‐[18F]fluoromethyl‐phenyl)‐2‐amino‐propionic acid (2‐[18F]FMLP), as compared to 4‐[18F]‐fluoromethyl‐l‐phenylalanine (4‐[18F]FMLP), was caused by an intramolecular interaction between the CH2F group on the 2‐position of the phenyl ring and the ammonium group of the amino acid. As the presence of nonradioactive (S)‐3‐(2‐fluoromethyl‐phenyl)‐2‐amino‐propionic acid (2FMLP) in a concentration up from 10−6 mol/L reduces considerably the defluorination rate due to the formation of dimers, conventional experimental methods, like spectroscopy, cannot be performed for the study of the hydrolysis in no‐carrier‐added conditions occurring at a concentration range of about 5.0 10−10 mol/L. In the present study, we aim to provide a proof that supports aforementioned hypothesis as well as to establish a kinetic model and to put forward accompanying rate equations for this hydrolysis reaction by combining ab initio quantum chemical calculations and kinetic data. The calculations of the optimized geometries and the corresponding energies of the reactants involved in the hydrolysis of 2‐[18F]FMLP and 4‐[18F]FMLP were performed at the DFT[B3LYP/6‐31++G**] level of theory. Interpretation of these data reveals that in 2‐[18F]FMLP three intramolecular hydrogen bond interactions can be identified that are not present in 4‐[18F]FMLP. The most important interaction is the one between the amino acid ammonium group and the benzylic fluorine atom, rendering the rupture of the CF bond much more favorable. These findings align with the experimental data and enabled us to put forward the rate expressions that define the unexpected pseudo–zero‐order defluorination reaction of 2‐[18F]FMLP at neutral pH. This study also proves that in the development of [18F]‐benzylfluoride containing tracers present‐day quantum chemical calculations are capable of predicting intramolecular interactions, affecting their reactivity toward hydrolysis at the no‐carrier‐added level. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 705–711, 2012
On Polarizing Outranking Relations with Large Performance Differences
Authors: Bisdorff Raymond
Published: May 2012

We introduce a bipolarly extended veto principle—a positive, as well as negative, large performance differences polarization—which allows us to extend the definition of the classical outranking relation in such a way that the identity between its asymmetric part and its codual relation is preserved. Copyright © 2012 John Wiley & Sons, Ltd.
Evaluation of the reliability of high concentrator GaAs solar cells by means of temperature accelerated aging tests
Authors: Núñez N. , González J. R. , Vázquez M. , Algora C. , Espinet P.
Published: May 2012

Evaluating the reliability, warranty period, and power degradation of high concentration solar cells is crucial to introducing this new technology to the market. The reliability of high concentration GaAs solar cells, as measured in temperature accelerated life tests, is described in this paper. GaAs cells were tested under high thermal accelerated conditions that emulated operation under 700 or 1050 suns over a period exceeding 10 000 h. Progressive power degradation was observed, although no catastrophic failures occurred. An Arrhenius activation energy of 1.02 eV was determined from these tests. The solar cell reliability [R(t)] under working conditions of 65°C was evaluated for different failure limits (1–10% power loss). From this reliability function, the mean time to failure and the warranty time were evaluated. Solar cell temperature appeared to be the primary determinant of reliability and warranty period, with concentration being the secondary determinant. A 30‐year warranty for these 1 mm2‐sized GaAs cells (manufactured according to a light emitting diode‐like approach) may be offered for both cell concentrations (700 and 1050 suns) if the solar cell is operated at a working temperature of 65°C. Copyright © 2012 John Wiley & Sons, Ltd.
An Ill‐posed inverse problem in enzymatic kinetics: Jack‐Bean urease denaturation by an anionic surfactant
Authors: Borges E. , Menezes D. C. , Braga J. P.
Published: May 2012

A neural network procedure is applied to solve an ill‐posed inverse problem in chemical kinetics relevant to chemical and biological areas; calculation of rate constants for the jack‐bean urease denaturation by an anionic surfactant agent from experimental enzyme concentrations. The efficiency of the algorithm proposed is compared with the Simplex and the Levenberg–Marquardt techniques, often used in nonlinear regression methods to solve this kind of kinetics problem. The neural network approach is numerically stable and robust with respect to different initial guesses for the rate constants and noises in experimental data. © 2012 Wiley Periodicals, Inc.
The molecular structure of AgBr2 and AgBr2+. A benchmark CASSCF, CASPT2, and averaged coupled pair functional study
Authors: Ramírez‐Solís A.
Published: May 2012

The ground states of AgBr2 and AgBr2+ have been predicted to be 2B2 and 1A1 bent structures (θ = 67° and θ = 47°, respectively) using complete active space self‐consistent field (CASSCF) and multireference second order perturbation theory (J. Chem. Phys., 1999, 111, 8925). Because CuF2, CuCl2, and AgCl2 are known to be linear, the ground states of AgBr2 and AgBr2+ have been studied through benchmark ab initio CASSCF(21,15), multireference second‐order perturbation theory and averaged coupled pair functional calculations using very large and especially developed valence basis sets. The bent nature of the ground state of the AgBr2+ ion is confirmed, but for AgBr2 the absolute minimum of the ground state is found to be 2Πg in the linear centrosymmetric structure with the present large optimized basis sets at all levels of theory. Also, a significant Ag‐Br bond length reduction was obtained for the cation with respect to the previous value. These results show the crucial role played by the quality of the valence atomic basis sets for this type of transition metal molecules on key properties such as the equilibrium geometry. New equilibrium geometries, vibrational frequencies and ionization potentials are presented. © 2012 Wiley Periodicals, Inc.
Organic ion yield enhancement in secondary ion mass spectrometry using water vapour injection
Authors: Mouhib T. , Delcorte A. , Poleunis C. , Bertrand P.
Published: May 2012

The effects of water (H2O) and deuterated water (D2O) vapour, injected closely to the analyzed surface at relatively high pressure, on the enhancement of the ion yield in secondary ion mass spectrometry (SIMS) was investigated for a set of organic samples. The results show that the same signal enhancements occurred either upon Ga+ or C60+ bombardment. In addition, the increase of H2O vapour pressure during the bombardment causes a specific enhancement of the protonated ion intensity. For instance, the presence of H2O vapour induces an enhancement by one order of magnitude of the [M + H]+ static SIMS intensity for the antioxidant Irgafos 168 and by more than two times for the amino acids. Copyright © 2012 John Wiley & Sons, Ltd.
History's “Illegibles”: National Indeterminacy in Istria
Authors: Ballinger Pamela
Published: May 2012

In the 1990s, the Julian (Giulian) Region that includes the cities of Trieste and Gorizia and the Istrian peninsula attracted the renewed attention of scholars for its qualities as a space in which both cosmopolitanism and nationalist polarization had flourished in the late Habsburg era. Although a healthy debate exists as to the degree to which forms of interethnic tolerance remain a feature of everyday life in these areas, most historians agree that this region underwent a series of increasing nationalizations (Italian, Slovene, Croatian, and Yugoslav) that began in the nineteenth century and culminated in the partisan anti-Fascist uprising and massive demographic shifts after World War II, as the majority of Istria's “Italian” population (together with a significant number of individuals self-identifying as Slovene or Croat) migrated from the territory that passed from Italian to Yugoslav control. The historiography of the modern era in the Julian Region has thus confirmed many of the assumptions made by nationalist activists along this classic “language frontier” about the inevitability, exclusivity, and irreversibility of ethnonational identifications.
Drama Offstage in Tbilisi
Authors: Brown Mark
Published: May 2012

Report on the Tbilisi International Festival of Theatre, held in Tbilisi, Georgia, 14 September to 8 October 2011.
Developing a framework for the use of discount rates in actuarial work ‐ Abstract of the Edinburgh discussion
Authors: Cowling Charles
Published: May 2012

This abstract relates to the following paper:

CowlingC.A., FranklandR., HailsR.T.G., KempM.H.D., LosebyR.L., OrrJ.B., and SmithA.D.Developing a framework for the use of discount rates in actuarial work. British Actuarial Journal, doi:10.1017/S1357321712000013
Second International comparative study of mortality tables for pension fund retirees
Authors: Sithole T. Z. , Haberman S. , Verrall R. J.
Published: May 2012

This paper contains an update to the first international comparative study of mortality tables carried out in 2006. It examines the mortality assumptions used in the valuation of pension liabilities in a number of different countries. The results are considered in relation to the underlying population mortality rates, in order to isolate the strength of the mortality assumptions being applied. It is found that there is evidence of a lack of consistency between countries, and that this has not changed since the previous study.
A Bayesian smoothing spline method for mortality modelling
Authors: Luoma Arto , Puustelli Anne , Koskinen Lasse
Published: May 2012

We propose a new method for two-dimensional mortality modelling. Our approach smoothes the data set in the dimensions of cohort and age using Bayesian smoothing splines. The method allows the data set to be imbalanced, since more recent cohorts have fewer observations. We suggest an initial model for observed death rates, and an improved model which deals with the numbers of deaths directly. Unobserved death rates are estimated by smoothing the data with a suitable prior distribution. To assess the fit and plausibility of our models we perform model checks by introducing appropriate test quantities. We show that our final model fulfils nearly all requirements set for a good mortality model.
Dissolved platinum in major rivers of East Asia: Implications for the oceanic budget
Authors: Soyol‐Erdene Tseren‐Ochir , Huh Youngsook
Published: May 2012

Dissolved platinum concentrations of eleven large pristine river systems in East Asia (∼200 samples) were determined to better constrain the oceanic platinum budget. Most samples had concentrations less than 1.4 pM; relatively high concentrations up to 5.8 pM were measured in only approximately 6% of the samples. The median Pt concentrations of the individual river systems had only a small range, from 0.18 pM (Duman) to 0.63 pM (Huang He), and the difference in Pt yield mainly resulted from the difference in runoff. The rivers draining the eastern Tibetan Plateau – the Salween, Mekong, Chang Jiang (Yangtze), Hong (Red), and Huang He (Yellow) – had higher Pt yield than the rivers of the Russian Far East – the Amur, Lena, Yana, Indigirka, and Kolyma. If the discharge‐weighted mean Pt concentration of our samples (0.36 pM) is extrapolated globally, the estimated riverine flux of dissolved Pt to the ocean is 13 × 103 mol y−1. Based on this riverine flux, the estimated oceanic residence time of Pt is 24 ± 10 kyrs. A 50% release and 50% uptake of Pt in estuaries would modify this to 16 kyrs and 45 kyrs, respectively.
Distribution, variability and sources of tropospheric ozone over south China in spring: Intensive ozonesonde measurements at five locations and modeling analysis
Authors: Zhang Yiqiang , Liu Hongyu , Crawford James H. , Considine David B. , Chan Chuenyu , Oltmans Samuel J. , Thouret Valerie
Published: May 2012

We examine the characteristics of the spatial distribution and variability of tropospheric ozone (O3) by analysis of 93 ozonesonde profiles obtained at five stations over south China (18–30°N) during a field campaign in April–May 2004. We use a global 3‐D chemical transport model (GEOS‐Chem) to interpret these characteristics and to quantify the sources of tropospheric O3 over south China during this period. The observed tropospheric O3 mixing ratios showed strong spatiotemporal variability due to a complex interplay of various dynamical and chemical processes. A prominent feature in the upper and middle troposphere (UT/MT) was the frequent occurrence of high O3mixing ratios shown as tongues extending down from the lower stratosphere or as isolated layers at all stations. The model largely captured the observed pattern of day‐to‐day variability in tropospheric O3 mixing ratios at all stations, but often underestimated those tongues or isolated layers of O3enhancements observed in the UT/MT, especially at low‐latitude stations. We found that tropospheric O3 along the southeast China coast was mainly produced within Asia. Lightning NOx emissions (over South Asia and equatorial Africa) and/or stratospheric influences were responsible for major events of high O3observed in the UT/MT at all stations. Underestimated contributions of these sources likely led to the model's underestimate in the low‐latitude UT/MT O3. This study emphasizes the need for improved understanding of lightning NOx emissions and stratospheric influences over the Eurasian and African continents and for better representation of these processes in current global models.
Transition due to base roughness in a dense granular flow down an inclined plane
Authors: Kumaran V. , Maheshwari S.
Published: May 2012

Particle simulations based on the discrete element method are used to examine the effect of base roughness on the granular flow down an inclined plane. The base is composed of a random configuration of fixed particles, and the base roughness is decreased by decreasing the ratio of diameters of the base and moving particles. A discontinuous transition from a disordered to an ordered flow state is observed when the ratio of diameters of base and moving particles is decreased below a critical value. The ordered flowing state consists of hexagonally close packed layers of particles sliding over each other. The ordered state is denser (higher volume fraction) and has a lower coordination number than the disordered state, and there are discontinuous changes in both the volume fraction and the coordination number at transition. The Bagnold law, which states that the stress is proportional to the square of the strain rate, is valid in both states. However, the Bagnold coefficients in the ordered flowing state are lower, by more than two orders of magnitude, in comparison to those of the disordered state. The critical ratio of base and moving particle diameters is independent of the angle of inclination, and varies very little when the height of the flowing layer is doubled from about 35 to about 70 particle diameters. While flow in the disordered state ceases when the angle of inclination decreases below 20°, there is flow in the ordered state at lower angles of inclination upto 14°.
Plasmons in electrostatically doped graphene
Authors: Thongrattanasiri Sukosin , Silveiro Iván , Javier García de Abajo F.
Published: May 2012

Graphene has raised high expectations as a low-loss plasmonic material in which the plasmon properties can be controlled via electrostatic doping. Here, we analyze realistic configurations, which produce inhomogeneous doping, in contrast to what has been so far assumed in the study of plasmons in nanostructured graphene. Specifically, we investigate backgated ribbons, co-planar ribbon pairs placed at opposite potentials, and individual ribbons subject to a uniform electric field. Plasmons in backgated ribbons and ribbon pairs are similar to those of uniformly doped ribbons, provided the Fermi energy is appropriately scaled to compensate for finite-size effects such as the divergence of the carrier density at the edges. In contrast, the plasmons of a ribbon exposed to a uniform field exhibit distinct dispersion and spatial profiles that considerably differ from uniformly doped ribbons. Our results provide a road map to understand graphene plasmons under realistic electrostatic doping conditions.
Photocarrier radiometry of ion-implanted and thermally annealed silicon wafers with multiple-wavelength excitations
Authors: Huang Qiuping , Li Bincheng
Published: May 2012

The electronic transport properties of ion-implanted and thermally annealed silicon wafers and their effects on the room temperature photoluminescence have been investigated by a two-layer photocarrier radiometry (PCR) model with multiple-wavelength excitations. Simulations are carried out to show the dependences of the PCR amplitudes on the structural and transport properties (thickness, minority carrier lifetime, diffusion coefficient, and front surface recombination velocity) of the implanted layer with excitation in a wide spectral range, respectively. Experiments on As+ implanted and thermally annealed silicon wafers with ion fluences ranging from 5 × 1014 to 1 × 1016 cm−2 were performed, with 830 nm, 660 nm, and 405 nm excitations. Both the simulated and experimental results show that the transport properties of the implanted layer can be obtained by fitting the PCR amplitudes under the multi-wavelength excitations at a fixed modulation frequency to the theoretical model via a multi-parameter fitting procedure. The ion implantation and thermal annealing processes result in significant decreases of the minority carrier lifetime and diffusion coefficient of the implanted layer, and the recombination velocity at the front surface, and all three parameters decrease with the increasing ion fluence. The photoluminescence of the ion-implanted and thermally annealed wafers is significantly stronger than that of the non-implanted and non-annealed wafer, mainly due to the considerable decline of the front surface recombination velocity. In addition, the decreasing carrier diffusion coefficient of the implanted layer may be another reason for the enhancement of the photoluminescence under long-wavelength excitations.
Mesoscopic resistor as a self-calibrating quantum noise source
Authors: Bergeal N. , Schackert F. , Frunzio L. , Prober D. E. , Devoret M. H.
Published: May 2012

We present a method for the measurement of the noise of microwave amplifiers operating at the single photon level. It is based on the shot noise produced by a nanowire resistor in the hot electron regime. This noise source is simply controlled by a dc current and offers the advantage of being self-calibrating. After testing the noise source with a cryogenic high electron mobility transistor amplifier, we demonstrate its usefulness by calibrating a Josephson parametric amplifier operating near the quantum limit.
Two-photon fluorescence properties of curcumin as a biocompatible marker for confocal imaging
Authors: Kumar Abhishek , Li Lian , Chaturvedi Akanksha , Brzostowski Joseph , Chittigori Joshna , Pierce Susan , Samuelson Lynne A. , Sandman Daniel , Kumar Jayant
Published: May 2012

Two-photon (TP) fluorescence properties of an antioxidant and anti-tumor molecule, curcumin, were investigated. The two-photon absorption (TPA) action cross-section was measured in organic solvents and found to be 6 GM in tetrahydrofuran and 2 GM in dimethyl sulfoxide. The measured TPA cross-section is comparable to that of rhodamine 6G. One-photon and TP confocal microscopy has demonstrated that curcumin is internalized in cells and can be used for imaging applications. Our investigation indicates that curcumin is a viable biocompatible TP fluorescent marker.
Stoichiometry of SrTiO3 films grown by pulsed laser deposition
Authors: Liu G. Z. , Lei Q. Y. , Xi X. X.
Published: May 2012

We have investigated the effects of laser energy density and oxygen pressure on the cation stoichiometry of homoepitaxial (001) SrTiO3 thin film grown by pulsed laser deposition. A broad growth window was found for near stoichiometric, uniform SrTiO3 thin films. At oxygen pressures, at or below 10−2 Torr, laser energy density below around 1.0 J/cm2 is needed, whereas around 0.1 Torr, near stoichiometry can be reached for laser energy densities from 0.9 to 2.3 J/cm2. The kinetic energy of the ablated species is considered an important factor in affecting the film stoichiometry.
Effect of cold working in a magnetic field on the shape of a ferromagnetic nanocontact
Authors: Müller Marc , Montbrun Richard , Sürgers Christoph , Löhneysen Hilbert v.
Published: May 2012

The role of a magnetic field present during formation of a ferromagnetic nanocontact—established by mechanically pulling a thin dysprosium wire—is investigated. We demonstrate that the shape of the nanocontact depends on the strength and direction of the magnetic field applied during plastic deformation of the contact. The different contact shapes obtained after cycles of tensile or compressive stress are attributed to the rearrangement of magnetic domains during formation of the nanocontact by magnetoelastic coupling.
Magnitude-tunable sub-THz shear phonons in a non-polar GaN multiple-quantum-well p-i-n diode
Authors: Chen Chien-Cheng , Huang Huei-Min , Lu Tien-Chang , Kuo Hao-Chung , Sun Chi-Kuang
Published: May 2012

Coherent transverse acoustic phonons are optically generated and detected through the piezoelectric coupling between the build-in electric fields and shear strains of a non-polar GaN multiple quantum wells embedded in a p-n junction. By optical transient transmission change measurement, the phonon frequency is observed to be 0.4 THz which corresponds to a wavelength of 12.5 nm, the periodicity of the multiple quantum wells, and the estimated phonon velocity corresponds to the transverse acoustic phonon velocity in GaN. Moreover, we can magnify the driving amplitude of the generated shear phonons by increasing the reverse bias of the p-i-n diode.
Superresolution imaging of HIV in infected cells with FlAsH-PALM
Authors: Lelek Mickaël , Di Nunzio Francesca , Henriques Ricardo , Charneau Pierre , Arhel Nathalie , Zimmer Christophe
Published: May 2012

Imaging protein assemblies at molecular resolution without affecting biological function is a long-standing goal. The diffraction-limited resolution of conventional light microscopy (∼200–300 nm) has been overcome by recent superresolution (SR) methods including techniques based on accurate localization of molecules exhibiting stochastic fluorescence; however, SR methods still suffer important restrictions inherent to the protein labeling strategies. Antibody labels are encumbered by variable specificity, limited commercial availability and affinity, and are mostly restricted to fixed cells. Fluorescent protein fusions, though compatible with live cell imaging, substantially increase protein size and can interfere with their biological activity. We demonstrate SR imaging of proteins tagged with small tetracysteine motifs and the fluorescein arsenical helix binder (FlAsH-PALM). We applied FlAsH-PALM to image the integrase enzyme (IN) of HIV in fixed and living cells under experimental conditions that fully preserved HIV infectivity. The obtained resolution (∼30 nm) allowed us to characterize the distribution of IN within virions and intracellular complexes and to distinguish different HIV structural populations based on their morphology. We could thus discriminate ∼100 nm long mature conical cores from immature Gag shells and observe that in infected cells cytoplasmic (but not nuclear) IN complexes display a morphology similar to the conical capsid. Together with the presence of capsid proteins, our data suggest that cytoplasmic IN is largely present in intact capsids and that these can be found deep within the cytoplasm. FlAsH-PALM opens the door to in vivo SR studies of microbial complexes within host cells and may help achieve truly molecular resolution.
Junctate is a Ca
2
+
-sensing structural component of Orai1 and stromal interaction molecule 1 (STIM1)
Authors: Srikanth Sonal , Jew Marcus , Kim Kyun-Do , Yee Ma-Khin , Abramson Jeff , Gwack Yousang
Published: May 2012

Orai1 and stromal interaction molecule (STIM)1 are critical components of Ca
2+
release-activated Ca
2+
(CRAC) channels. Orai1 is a pore subunit of CRAC channels, and STIM1 acts as an endoplasmic reticulum (ER) Ca
2+
sensor that detects store depletion. Upon store depletion after T-cell receptor stimulation, STIM1 translocates and coclusters with Orai1 at sites of close apposition of the plasma membrane (PM) and the ER membrane. However, the molecular components of these ER-PM junctions remain poorly understood. Using affinity protein purification, we uncovered junctate as an interacting partner of Orai1-STIM1 complex. Furthermore, we identified a Ca
2+
-binding EF-hand motif in the ER-luminal region of junctate. Mutation of this EF-hand domain of junctate impaired its Ca
2+
binding and resulted in partial activation of CRAC channels and clustering of STIM1 independently of store depletion. In addition to the known mechanisms of STIM1 clustering (i.e., phosphoinositide and Orai1 binding), our study identifies an alternate mechanism to recruit STIM1 into the ER-PM junctions via binding to junctate. We propose that junctate, a Ca
2+
-sensing ER protein, is a structural component of the ER-PM junctions where Orai1 and STIM1 cluster and interact in T cells.
Mass spectral molecular networking of living microbial colonies
Authors: Watrous Jeramie , Roach Patrick , Alexandrov Theodore , Heath Brandi S. , Yang Jane Y. , Kersten Roland D. , van der Voort Menno , Pogliano Kit , Gross Harald , Raaijmakers Jos M. , Moore Bradley S. , Laskin Julia , Bandeira Nuno , Dorrestein Pieter C.
Published: May 2012

Integrating the governing chemistry with the genomics and phenotypes of microbial colonies has been a “holy grail” in microbiology. This work describes a highly sensitive, broadly applicable, and cost-effective approach that allows metabolic profiling of live microbial colonies directly from a Petri dish without any sample preparation. Nanospray desorption electrospray ionization mass spectrometry (MS), combined with alignment of MS data and molecular networking, enabled monitoring of metabolite production from live microbial colonies from diverse bacterial genera, including
Bacillus subtilis, Streptomyces coelicolor, Mycobacterium smegmatis
, and
Pseudomonas aeruginosa
. This work demonstrates that, by using these tools to visualize small molecular changes within bacterial interactions, insights can be gained into bacterial developmental processes as a result of the improved organization of MS/MS data. To validate this experimental platform, metabolic profiling was performed on
Pseudomonas
sp. SH-C52, which protects sugar beet plants from infections by specific soil-borne fungi [R. Mendes et al. (2011)
Science
332:1097–1100]. The antifungal effect of strain SH-C52 was attributed to thanamycin, a predicted lipopeptide encoded by a nonribosomal peptide synthetase gene cluster. Our technology, in combination with our recently developed peptidogenomics strategy, enabled the detection and partial characterization of thanamycin and showed that it is a monochlorinated lipopeptide that belongs to the syringomycin family of antifungal agents. In conclusion, the platform presented here provides a significant advancement in our ability to understand the spatiotemporal dynamics of metabolite production in live microbial colonies and communities.
Effect of the hydrostatic pressure on otolith growth of early juveniles of Nile tilapia Oreochromis niloticus
Authors: Correia A. T. , Coimbra A. M. , Damasceno‐Oliveira A.
Published: May 2012

Nile tilapia Oreochromis niloticus early juveniles were maintained for 2 weeks in a pressurized system under a controlled photoperiod, at constant salinity and temperature. Groups of fish were exposed to one of three absolute hydrostatic pressure (HP) regimes: (1) a constant normal atmospheric pressure (100 kPa), (2) a constant 40 m pressure (500 kPa) or (3) a semi‐diurnal cyclic vertical migration (100–500 kPa). No significant differences were detected in otolith size and incremental periodicity among the three HP treatments, suggesting that HP does not affect otolith growth of early juveniles O. niloticus.
Behavioural compensation reduces energy expenditure during migration hyperphagia in a large bird
Authors: Guillemette Magella , Richman Samantha E. , Portugal Steven J. , Butler Patrick J.
Published: May 2012

1. Bird migration is often seen as the summit of animal performance. Because higher foraging effort associated with fuelling and increased flight activity should generate maximum level of energy turnover, we expect the migratory process to be constrained by energy, whether it is energy expenditure or energy intake.

2. We used implanted data loggers to continuously monitor foraging effort, flight activity and heart rate (as a proxy for rate of energy expenditure), in a wild migratory sea duck before and after moult migration to test the energy budget limitation hypothesis.

3. We show that despite the fact that departing birds forage at three times the level observed during post‐migration, daily energy expenditure (DEE) remains the same when periods before and after migration are compared.

4. In an attempt to determine how the birds achieve such a feat, we compared heart rate when active (feeding and flying) for the periods before and after migration and found no significant difference for feeding and flight heart rate. However, heart rate during periods of inactivity was significantly lower during fuelling which together with a reduced time spent flying completely counteracted the observed high energy costs of foraging.

5. The time spent active represented a tiny proportion (8–20%) of the 24‐h time budget suggesting that energy minimization and an optimization process may be at work here, confounding any apparent support for the energy budget limitation hypothesis. We thus concluded that similar DEE before and after migration could be owing to the bird’s inability to increase energy expenditure over a certain limit or to the survival costs associated with a certain level of physical exertion. Nevertheless, our results indicate that behavioural, and possibly physiological, compensation may be used as a mechanism to reduce the overall energy cost of fuelling in migrating birds.
Persistence of vigilance and flight response behaviour in wild reindeer with varying domestic ancestry
Authors: REIMERS E. , RØED K. H. , COLMAN J. E.
Published: May 2012

Knowledge about changes in behavioural traits related to wildness and tameness is for most mammals lacking, despite the increased trend of using domestic stock to re‐establish wild populations into historical ranges. To test for persistence of behavioural traits of wild reindeer (Rangifer tarandus L.) exposed to hunting, we sampled DNA, vigilance and flight responses in wild reindeer herds with varying domestic ancestry. Analyses of 14 DNA microsatellite loci revealed a dichotomous main genetic structure reflecting their native origin, with the Rondane reindeer genetically different from the others and with least differentiation towards the Hardangervidda reindeer. The genetic clustering of the reindeer in Norefjell‐Reinsjøfjell, Ottadalen and Forollhogna, together with domestic reindeer, supports a predominant domestic origin of these herds. Despite extensive hunting in all herds, the behavioural measures indicate increasing vigilance, alert and flight responses with increasing genetic dissimilarity with domestic herds. Vigilance frequency and time spent vigilant were higher in Rondane compared to Hardangervidda, which again were higher than herds with a domestic origin. We conclude that previous domestication has preserved a hard wired behavioural trait in some reindeer herds exhibiting less fright responses towards humans that extensive hunting has, but only slightly, altered. This brings novel and relevant knowledge to discussions about genetic diversity of wildlife in general and wild reindeer herds in Norway in specific.
Differential modulations of ipsilateral and contralateral beta (de)synchronization during unimanual force production
Authors: van Wijk B. C. M. , Beek P. J. , Daffertshofer A.
Published: May 2012

Unilateral movement is usually accompanied by ipsilateral activity in the primary motor cortex (M1). It is still largely unclear whether this activity reflects interhemispheric ‘cross‐talk’ of contralateral M1 that facilitates movement, or results from processes that inhibit motor output. We investigated the role of beta power in ipsilateral M1 during unimanual force production. Significant ipsilateral beta desynchronization occurred during continuous dynamic but not during static force production. Moreover, event‐related time–frequency analysis revealed bilateral desynchronization patterns, whereas post‐movement synchronization was confined to the contralateral hemisphere. Our findings indicate that ipsilateral activation is not merely the result of interhemispheric cross‐talk but involves additional processes. Given observations of differential blood oxygen level‐dependent responses in ipsilateral and contralateral M1, and the correlation between beta desynchronization and the firing rate of pyramidal tract neurons in contralateral M1 during movement, we speculate that beta desynchronization in contra‐ and ipsilateral M1 arises from distinct neural activation patterns.
Screening by pulse CO‐oximetry for environmental tobacco smoke exposure in preanesthetic children
Authors: Cardwell Kathryn , Pan Zhaoxing , Boucher Rebecca , Zuk Jeannie , Friesen Robert H.
Published: May 2012

Objective:  The purpose of this study was to evaluate the ability of multiple wavelength pulse CO‐oximetry (SpCO) to screen for environmental tobacco smoke (ETS) exposure in children.

Background:  Exposure to ETS is associated with an increased risk of perioperative respiratory complications in children. It is often difficult to obtain an accurate history for ETS exposure, so a preoperative screening tool is desirable. Carbon monoxide is a measurable product of tobacco combustion. Multiple wavelength pulse CO‐oximetry is a recently developed point‐of‐care monitor.

Methods:  Following IRB approval and parental consent, 220 children aged 1–16 years having outpatient surgical procedures were enrolled. SpCO was measured preoperatively three times with the Radical‐7 Rainbow SET CO‐oximeter (Masimo, Irvine, CA, USA). Immediately following induction of anesthesia, a blood sample for laboratory measurement of carboxyhemoglobin (COHb) and serum cotinine was obtained. Regression analysis determined the correlation of SpCO with serum cotinine values. Receiver operator characteristic (ROC) curves analyzed the discriminating ability of SpCO or COHb to predict ETS exposure based on cotinine cutoff values known to be present in children exposed to ETS. Agreement of SpCO and COHb values was assessed using Bland–Altman plots.

Results:  SpCO did not correlate with cotinine (R2 = 0.005). Both SpCO and COHb had poor discriminating ability for ETS exposure (area under the ROC curve = 0.606 and 0.562, respectively). SpCO values had poor agreement with COHb values.

Conclusions:  The point‐of‐care multiple wavelength pulse CO‐oximeter does not appear to be a useful preoperative screening tool for ETS exposure in children.
Hemodynamic changes during spinal anesthesia in premature infants with congenital heart disease undergoing inguinal hernia correction
Authors: Shenkman Ze’ev , Johnson Victor M. , Zurakowski David , Arnon Shmuel , Sethna Navil F.
Published: May 2012

Introduction:  There are conflicting reports on the effects of spinal anesthesia (SA) on hemodynamics. Data on the hemodynamic effects of SA in infants with congenital heart disease (CHD) are limited.

Methods:  We reviewed our experience with 44 unsupplemented SA with 1 mg·kg−1 of either hyperbaric tetracaine or bupivacaine in premature and former premature infants with noncyanotic CHD. Hemodynamics and oxyhemoglobin saturation (SpO2) were assessed. Neither preoperative fluid boluses nor atropine was administered to any of the infants.

Results:  There was no significant change in systolic, diastolic, or mean blood pressures from pre‐SA induction compared with end of surgery. Heart rate showed a small but systematic decline (mean change of 10 beats per minute, P < 0.01) but was within the normative range values for age. There was a small, but clinically insignificant increase in SpO2 across the time course. Intraoperatively, two infants developed transient apneic spells. No infant developed postoperative apnea, oxygen desaturation, or bradycardia.

Conclusions:  The data suggest that SA with 1 mg·kg−1 of either hyperbaric tetracaine or bupivacaine can be used safely as the sole anesthetic for inguinal hernia repair in infants with noncyanotic CHD even when fluid restricted and apparently causes minimal respiratory complications in these infants.
Depression and diabetes in India: perspectives and recommendations
Authors: Mendenhall E. , Narayanan G. , Prabhakaran D.
Published: May 2012

Diabet. Med. 29, e308–e311 (2012)

As diabetes prevalence shifts from affluent to lower‐income groups in India, focus on depression in diabetes will become essential. This paper describes four perspectives through which depression and diabetes should be understood in the Indian context. We consider (1) how rapid socio‐economic and demographic changes contribute to increased co‐occurring diabetes and depression; (2) how social, cultural and economic factors in the Indian context contribute to depression and therefore play an important role in diabetes care; (3) biological and behavioural pathways between depression and diabetes; and (4) the role of health systems in depression, diabetes and their overlap. We conclude with recommendations for future research and policy on this topic in India.
Adaptive Compression of Texture Pyramids
Authors: Andujar C.
Published: May 2012

High‐quality texture minification techniques, including trilinear and anisotropic filtering, require texture data to be arranged into a collection of pre‐filtered texture maps called mipmaps. In this paper, we present a compression scheme for mipmapped textures which achieves much higher quality than current native schemes by exploiting image coherence across mipmap levels. The basic idea is to use a high‐quality native compressed format for the upper levels of the mipmap pyramid (to retain efficient minification filtering) together with a novel compact representation of the detail provided by the highest‐resolution mipmap. Key elements of our approach include delta‐encoding of the luminance signal, efficient encoding of coherent regions through texel runs following a Hilbert scan, a scheme for run encoding supporting fast random‐access, and a predictive approach for encoding indices of variable‐length blocks. We show that our scheme clearly outperforms native 6:1 compressed texture formats in terms of image quality while still providing real‐time rendering of trilinearly filtered textures.
Reverse Electrical Remodeling by Cardiac Resynchronization Therapy: Prevalence and Clinical Impact
Authors: SEBAG FREDERIC A. , MARTINS RAPHAEL P. , DEFAYE PASCAL , HIDDEN‐LUCET FRANÇOISE , MABO PHILIPPE , DAUBERT JEAN‐CLAUDE , LECLERCQ CHRISTOPHE
Published: May 2012

Intrinsic QRS Narrowing with CRT. Background: Cardiac resynchronization therapy (CRT) improves left ventricular ejection fraction (LVEF) in patients with congestive heart failure, LV systolic dysfunction, and a wide QRS complex. Previous reports suggest that CRT may also induce electrical remodeling but the impact on clinical outcome remains unknown.

Objective: We sought to determine (1) if chronic CRT induces a relevant shortening of the intrinsic QRS (iQRS), (2) whether changes in the native conduction system correlate with clinical or echocardiographic response to CRT, and (3) to identify predictors of iQRS width shortening.

Methods: We prospectively included 85 consecutive patients with left bundle‐branch block who received a CRT device in 3 French centers. NYHA class, iQRS duration, LVEF, and left ventricular volumes were assessed before and 1 year after CRT implantation. Clinical and echocardiographic CRT responders were defined respectively as NYHA class improvement >1 class without heart failure hospitalization and an increase of LVEF by ≥10% and/or a decrease in LVESV by ≥15%. Electrocardiographic responders were defined as a decrease in iQRS duration by ≥20 ms.

Results: Baseline and 1‐year follow‐up mean iQRS durations were, respectively, 168.0 ± 19.7 ms and 149.6 ± 31.6 ms (P < 0.0001). Electrocardiographic response, observed in 43/85 patients (51%), was associated with a greater rate of clinical (P = 0.035) and echocardiographic (P = 0.023) response. Younger age, male gender, and longer baseline QRS width were independent predictors of electrocardiographic response.

Conclusion: CRT decreases iQRS duration. A reduction of at least 20 ms in iQRS duration is associated with better clinical and echocardiographic response. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1219–1227, November 2012)
Semiparametric Maximum Likelihood Methods for Analyzing Genetic and Environmental Effects with Case‐Control Mother–Child Pair Data
Authors: Chen Jinbo , Lin Dongyu , Hochner Hagit
Published: May 2012

Summary Case‐control mother–child pair design represents a unique advantage for dissecting genetic susceptibility of complex traits because it allows the assessment of both maternal and offspring genetic compositions. This design has been widely adopted in studies of obstetric complications and neonatal outcomes. In this work, we developed an efficient statistical method for evaluating joint genetic and environmental effects on a binary phenotype. Using a logistic regression model to describe the relationship between the phenotype and maternal and offspring genetic and environmental risk factors, we developed a semiparametric maximum likelihood method for the estimation of odds ratio association parameters. Our method is novel because it exploits two unique features of the study data for the parameter estimation. First, the correlation between maternal and offspring SNP genotypes can be specified under the assumptions of random mating, Hardy–Weinberg equilibrium, and Mendelian inheritance. Second, environmental exposures are often not affected by offspring genes conditional on maternal genes. Our method yields more efficient estimates compared with the standard prospective method for fitting logistic regression models to case‐control data. We demonstrated the performance of our method through extensive simulation studies and the analysis of data from the Jerusalem Perinatal Study.
Childbirth attendance strategies and their impact on maternal mortality and morbidity in low‐income settings: a systematic review
Authors: PYONE THIDAR , SORENSEN BJARKE LUND , TELLIER SIRI
Published: May 2012

Objective. To review quantitative evidence of the effect on maternal health of different childbirth attendance strategies in low‐income settings. Design. Systematic review. Methods. Studies using quantitative methods, referring to the period 1987–2011, written in English and reporting the impact of childbirth attendance strategies on maternal mortality or morbidity in low‐income settings were included. Guidelines developed by the Cochrane collaboration and the Centre for Review and Dissemination, University of York were followed. The included articles were read and sorted by category of strategy that emerged from the reading. Results. The search criteria yielded 29 articles. The following three main categories of strategy emerged: (i) those primarily intended to improve quality of care; (ii) “centrifugal strategies,” which sought to bring services to the women; and (iii) “centripetal strategies,” which sought to bring the women to the services. Few of the studies had a design that provided strong evidence for the impact of the strategy concerned. Conclusions. The evidence emerging from the studies was difficult to compare, because concepts were not defined in a consistent manner (such as “skilled birth attendance”) and many studies examined the impact of a package of interventions without ferreting out the impact of individual components. Yet, some studies described individual aspects with great promise (such as cost, transport, outreach‐friendly drugs or targeted training). There is a need for clearer conceptual frameworks, including some which permit assessment of packages of interventions.
Effects of perceptual and movement ranges on joint predator–prey distributions
Authors: Fraker Michael E. , Luttbeg Barney
Published: May 2012

We developed a spatially‐explicit individual‐based model to study how limited perceptual and movement ranges affect spatial predator–prey interactions. Earlier models of ‘predator–prey space games’ were often developed by modifying ideal free distribution models, which are spatially‐implicit and also assume that individuals are omniscient, although some more recent models have relaxed these assumptions. We found that under some conditions, the spatially‐explicit model generated similar predictions to previous models. However, the model showed that limited range in a spatially‐explicit context generated different predictions when 1) predator density and range are both small, and 2) when the predator movement range varied while the prey range was small. The model suggests that the differences were the result of 1) movement range changing the value of information sources and thus changing the behavior of individual predators and prey and 2) movement range limiting the ability of individuals to exploit the environment.