bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of winter precipitation and temperature on northern Eurasian streamflow trends
Authors: Troy Tara J. , Sheffield Justin , Wood Eric F.
Published: January 2012

Eurasian river discharge into the Arctic Ocean has steadily increased during the 20th century, and many studies have documented the spatial distribution of the trends and hypothesized the causes. There is a large variation in the scope of these studies, including the spatial scale of interest, and they often lack consistency in the time period analyzed. Studies have shown a connection between changes in the seasonal snowpack and discharge, but they have been constrained by the limitations of the snow observational network, which contains few long‐term stations. This study overcomes these problems by using both in situ observations and a land surface model to evaluate the role snowpack changes have had on increases in runoff across northern Eurasia from 1936 through 1999. Our analysis shows consistent trends in both observations and model predictions. Increases in cold season precipitation propagate into increases in maximum snow water equivalent, which lead to increases in runoff. A series of model experiments demonstrate that the nonlinear interaction between winter precipitation and temperature has driven changes in the snowpack, which are manifested in the modeled runoff trends. Given that winter precipitation is expected to continue to increase and temperatures to warm during the 21st century in this region, these results point to the importance in understanding how the projected changes will influence the seasonal snowpack, which may have important consequences for streamflow in this region and freshwater export to the Arctic Ocean.
HOx budgets during HOxComp: A case study of HOx chemistry under NOx‐limited conditions
Authors: Elshorbany Y. F. , Kleffmann J. , Hofzumahaus A. , Kurtenbach R. , Wiesen P. , Brauers T. , Bohn B. , Dorn H.‐P. , Fuchs H. , Holland F. , Rohrer F. , Tillmann R. , Wegener R. , Wahner A. , Kanaya Y. , Yoshino A. , Nishida S. , Kajii Y. , Martinez M. , Kubistin D. , Harder H. , Lelieveld J. , Elste T. , Plass‐Dülmer C. , Stange G. , Berresheim H. , Schurath U.
Published: January 2012

Recent studies have shown that measured OH under NOx‐limited, high‐isoprene conditions are many times higher than modeled OH. In this study, a detailed analysis of the HOx radical budgets under low‐NOx, rural conditions was performed employing a box model based on the Master Chemical Mechanism (MCMv3.2). The model results were compared with HOx radical measurements performed during the international HOxComp campaign carried out in Jülich, Germany, during summer 2005. Two different air masses influenced the measurement site denoted as high‐NOx (NO, 1–3 ppbv) and low‐NOx (NO, < 1 ppbv) periods. Both modeled OH and HO2 diurnal profiles lay within the measurement range of all HOx measurement techniques, with correlation slopes between measured and modeled OH and HO2 around unity. Recently discovered interference in HO2 measurements caused by RO2 cross sensitivity was found to cause a 30% increase in measured HO2 during daytime on average. After correction of the measured HO2 data, the model HO2 is still in good agreement with the observations at high NOx but overpredicts HO2 by a factor of 1.3 to 1.8 at low NOx. In addition, for two different set of measurements, a missing OH source of 3.6 ± 1.6 and 4.9 ± 2.2 ppb h−1 was estimated from the experimental OH budget during the low‐NOx period using the corrected HO2 data. The measured diurnal profile of the HO2/OH ratio, calculated using the corrected HO2, is well reproduced by the MCM at high NOx but is significantly overestimated at low NOx. Thus, the cycling between OH and HO2 is better described by the model at high NOx than at low NOx. Therefore, similar comprehensive field measurements accompanied by model studies are urgently needed to investigate HOx recycling under low‐NOx conditions.
Global Joule heating index derived from thermospheric density physics‐based modeling and observations
Authors: Fedrizzi Mariangel , Fuller‐Rowell Tim J. , Codrescu Mihail V.
Published: January 2012

The primary operational impact of upper atmospheric neutral density variability is on satellite drag. Drag is the most difficult force to model mainly because of the complexity of neutral atmosphere variations driven by solar UV and EUV radiation power, magnetospheric energy input, and the propagation from below of lower atmosphere waves. Taking into account the self‐consistent interactions between neutral winds, composition, ion drifts, and ionization densities, first‐principles models are able to provide a more realistic representation of neutral density than empirical models in the upper atmosphere. Their largest sources of uncertainty, however, are the semiannual variations in neutral density and the magnitude, spatial distribution, and temporal evolution of the magnetospheric energy input. In this study, results from the physics‐based coupled thermosphere‐ionosphere‐plasmasphere electrodynamics (CTIPe) model and measurements from the CHAMP satellite are compared and used to improve the modeled thermospheric neutral density estimates. The good agreement between modeled and observed densities over an uninterrupted yearlong period of variable conditions gives confidence that the thermosphere‐ionosphere system energy influx from solar radiation and magnetospheric sources is reasonable and that Joule heating, the dominant source during geomagnetically disturbed conditions, is appropriately estimated. On the basis of the correlation between neutral density and energy injection, a global time‐dependent Joule heating index (JHI) is derived from the relationship between Joule heating computed by the CTIPe model and neutral density measured by the CHAMP satellite. Preliminary results show an improvement in density estimates using CTIPe JHI, demonstrating its potential for neutral density modeling applied to atmospheric drag determination.
Systematic Review of Effective Strategies for Reducing Screen Time Among Young Children
Authors: Schmidt Marie Evans , Haines Jess , O'Brien Ashley , McDonald Julia , Price Sarah , Sherry Bettylou , Taveras Elsie M.
Published: January 2012

Screen‐media use among young children is highly prevalent, disproportionately high among children from lower‐income families and racial/ethnic minorities, and may have adverse effects on obesity risk. Few systematic reviews have examined early intervention strategies to limit TV or total screen time; none have examined strategies to discourage parents from putting TVs in their children's bedrooms or remove TVs if they are already there. In order to identify strategies to reduce TV viewing or total screen time among children <12 years of age, we conducted a systematic review of seven electronic databases to June 2011, using the terms “intervention” and “television,” “media,” or “screen time.” Peer‐reviewed intervention studies that reported frequencies of TV viewing or screen‐media use in children under age 12 were eligible for inclusion. We identified 144 studies; 47 met our inclusion criteria. Twenty‐nine achieved significant reductions in TV viewing or screen‐media use. Studies utilizing electronic TV monitoring devices, contingent feedback systems, and clinic‐based counseling were most effective. While studies have reduced screen‐media use in children, there are several research gaps, including a relative paucity of studies targeting young children (n = 13) or minorities (n = 14), limited long‐term (>6 month) follow‐up data (n = 5), and few (n = 4) targeting removing TVs from children's bedrooms. Attention to these issues may help increase the effectiveness of existing strategies for screen time reduction and extend them to different populations.
A simple scheme for magnetic balance in four-component relativistic Kohn–Sham calculations of nuclear magnetic resonance shielding constants in a Gaussian basis
Authors: Olejniczak Małgorzata , Bast Radovan , Saue Trond , Pecul Magdalena
Published: January 2012

We report the implementation of nuclear magnetic resonance (NMR) shielding tensors within the four-component relativistic Kohn–Sham density functional theory including non-collinear spin magnetization and employing London atomic orbitals to ensure gauge origin independent results, together with a new and efficient scheme for assuring correct balance between the large and small components of a molecular four-component spinor in the presence of an external magnetic field (simple magnetic balance). To test our formalism we have carried out calculations of NMR shielding tensors for the HX series (X = F, Cl, Br, I, At), the Xe atom, and the Xe dimer. The advantage of simple magnetic balance scheme combined with the use of London atomic orbitals is the fast convergence of results (when compared with restricted kinetic balance) and elimination of linear dependencies in the basis set (when compared to unrestricted kinetic balance). The effect of including spin magnetization in the description of NMR shielding tensor has been found important for hydrogen atoms in heavy HX molecules, causing an increase of isotropic values of 10%, but negligible for heavy atoms.
Poynting vector, energy densities, and pressure of collective transverse electromagnetic fluctuations in unmagnetized plasmas
Authors: Schlickeiser R.
Published: January 2012

A systematic calculation of the electromagnetic properties (Poynting vector, electromagnetic energy, and pressure) of the collective transverse fluctuations in unmagnetized plasmas with velocity-anisotropic plasma particle distributions functions is presented. Time-averaged electromagnetic properties for monochromatic weakly damped wave-like fluctuations and space-averaged electromagnetic properties for monochromatic weakly propagating and aperiodic fluctuations are calculated. For aperiodic fluctuations, the Poynting vector as well as the sum of the space-averaged electric and magnetic field energy densities vanish. However, aperiodic fluctuations possess a positive pressure given by its magnetic energy density. This finite pressure density pa of aperiodic fluctuations has important consequences for the dynamics of cosmic unmagnetized plasmas such as the intergalactic medium after reionization. Adopting the standard cosmological evolution model, we show that this additional pressure changes the expansion law of the universe leading to further deceleration. Negative vacuum pressure counterbalances this deceleration to an accelerating universe provided that the negative vacuum pressure is greater than 1.5pa, which we estimate to be of the order 2.1 · 10−16 dyn cm−2.
Linear dependence and energy conservation in Gaussian wavepacket basis sets
Authors: Habershon Scott
Published: January 2012

We propose a method for dealing with the problem of linear dependence in quantum dynamics simulations employing over-complete Gaussian wavepacket (GWP) basis sets. In particular, by periodically projecting out redundant basis functions using the matching pursuit algorithm whilst simultaneously introducing GWPs which avoid linear dependence with the current basis set, we find that numerical conditioning of the equations-of-motion can be readily controlled. In applications to particle tunnelling in one- and two-dimensional potentials, this method allows us to reproduce the exact quantum-mechanical results with fewer GWP basis functions than similar calculations with non-adaptive basis sets, a result which we trace back to the improved energy conservation of our adaptive approach.
Interaction of lipid vesicle with silver nanoparticle-serum albumin protein corona
Authors: Chen Ran , Choudhary Poonam , Schurr Ryan N. , Bhattacharya Priyanka , Brown Jared M. , Chun Ke Pu
Published: January 2012

The physical interaction between a lipid vesicle and a silver nanoparticle (AgNP)-human serum albumin (HSA) protein “corona” has been examined. Specifically, the binding of AgNPs and HSA was analyzed by spectrophotometry, and the induced conformational changes of the HSA were inferred from circular dichroism spectroscopy. The fluidity of the vesicle, a model system for mimicking cell membrane, was found to increase with the increased exposure to AgNP-HSA corona, though less pronounced compared to that induced by AgNPs alone. This study offers additional information for understanding the role of physical forces in nanoparticle-cell interaction and has implications for nanomedicine and nanotoxicology.
Considerations on describing non-singlet spin states in variational second order density matrix methods
Authors: van Aggelen Helen , Verstichel Brecht , Bultinck Patrick , Van Neck Dimitri , Ayers Paul W.
Published: January 2012

Despite the importance of non-singlet molecules in chemistry, most variational second order density matrix calculations have focused on singlet states. Ensuring that a second order density matrix is derivable from a proper N-electron spin state is a difficult problem because the second order density matrix only describes one- and two-particle interactions. In pursuit of a consistent description of spin in second order density matrix theory, we propose and evaluate two main approaches: we consider constraints derived from a pure spin state and from an ensemble of spin states. This paper makes a comparative assessment of the different approaches by applying them to potential energy surfaces for different spin states of the oxygen and carbon dimer. We observe two major shortcomings of the applied spin constraints: they are not size consistent and they do not reproduce the degeneracy of the different states in a spin multiplet. First of all, the spin constraints are less strong when applied to a dissociated molecule than when they are applied to the dissociation products separately. Although they impose correct spin expectation values on the dissociated molecule, the dissociation products do not have correct spin expectation values. Secondly, both under “pure spin state conditions” and under “ensemble spin state” conditions is the energy a convex function of the spin projection. Potential energy surfaces for different spin projections of the same spin state may give a completely different picture of the molecule's bonding. The maximal spin projection always gives the most strongly constrained energy, but is also significantly more expensive to compute than a spin-averaged ensemble. In the dissociation limit, both the problem of nondegeneracy of equivalent spin projections, size-inconsistency and unphysical dissociation can be corrected by means of subspace energy constraints.
Can morphology tailoring improve the open circuit voltage of organic solar cells?
Authors: Ray Biswajit , Lundstrom Mark S. , Alam Muhammad A.
Published: January 2012

While the effect of interfacial morphology on the short circuit current (ISC) of organic photovoltaic devices (OPVs) is well known, its impact on open circuit voltage (VOC) and fill-factor (FF) are less clear. Since the output power of a solar cell Pout=ISCVOCFF, such understanding is critical for designing high-performance, morphology-engineered OPVs. In this letter, we provide an explicit analytical proof that any effort to radically improve VOC by tailoring bulk heterojunction morphology is futile, because any increase in ISC due to larger interface area is counterbalanced by corresponding increase in recombination current, so that the upper limit of VOCBHJ cannot exceed that of the corresponding planar heterojunction devices, i.e., VOCBHJ≤VOCPHJ. We discuss the implication of this VOC-constraint on the efficiency optimization of organic solar cells.
Atomic configuration of the interface between epitaxial Gd doped HfO2 high k thin films and Ge (001) substrates
Authors: Zhang Xinqiang , Tu Hailing , Guo Yiwen , Zhao Hongbin , Yang Mengmeng , Wei Feng , Xiong Yuhua , Yang Zhimin , Du Jun , Wang Wenwu
Published: January 2012

5 nm thick epitaxial Gd doped HfO2 (GHO) high k films were grown on Ge (001) substrates by pulsed laser deposition (PLD). Epitaxial growth mode and atomic microstructure at sharp interface of GHO film on Ge were investigated by reflection high energy electron diffraction (RHEED) and high resolution electron microscopy (HRTEM). The chemical bonding at the interface between GHO film and Ge substrate was identified through high resolution x-ray photoelectron spectroscopy (HRXPS). The fitted curves of Gd 3d core level provide evidence for the existence of Ge1+, Ge2+ and Ge3+ species. The atomic configuration of the interface between GHO and Ge with incomplete atomic planes has been revealed.
Nondestructive identification of isotopes using nuclear resonance fluorescence
Authors: Shizuma Toshiyuki , Hayakawa Takehito , Hajima Ryoichi , Kikuzawa Nobuhiro , Ohgaki Hideaki , Toyokawa Hiroyuki
Published: January 2012

Nondestructive identification of heavy isotopes concealed in a thick iron box has been demonstrated by using nuclear resonance fluorescence. A quasi-monochromatic photon beam produced by the collision of laser quanta with high energy electrons was used for resonant excitation of nuclear levels in 206Pb and 208Pb. By measuring the resonant γ rays emitted from 206Pb and 208Pb, each of these isotopes were clearly identified. The ratio of the effective thickness, i.e., concentration distribution, of these isotopes was deduced from the relative intensities of the measured nuclear resonance fluorescence strengths.
Review: The use of geographic information systems in wind turbine and wind energy research
Authors: Christidis Tanya , Law Jane
Published: January 2012

This paper is a review of wind energy articles that use geographic information systems (GIS). It is the hope of the authors that the article will inform renewable energy researchers of the potential for using GIS in their work, and geographers and spatial scientists to learn about the opportunities in wind turbine research. GIS can be used for wind energy planning to determine whether there is adequate wind energy at a site as well as whether the landscape and land-uses are appropriate for wind turbine developments. These types of GIS applications have been used worldwide, typically using previously collected data. To determine which sites are preferable, variables of interest are treated as distinct layers in GIS, and areas that are unsuitable for wind turbine development become evident. Areas that are not preferred for wind turbines are environmentally protected areas or landscapes that cannot be developed effectively. GIS is the ideal tool for identifying preferred sites for wind farms, especially when using decision support systems. Future decision support system research in GIS should consider on-site conditions as well as the opinion of stakeholders and local residents. Involving stakeholders in the decision-making process, either through increased communication or visualization activities that use GIS can lead to higher acceptance of wind turbine installations. Examining the failures and successes of other wind turbine installations may be informative for future developments
High-responsivity, low-noise, room-temperature, self-mixing terahertz detector realized using floating antennas on a GaN-based field-effect transistor
Authors: Sun J. D. , Sun Y. F. , Wu D. M. , Cai Y. , Qin H. , Zhang B. S.
Published: January 2012

Using only optical lithography, we have fabricated a GaN/AlGaN high-electron mobility transistor with distinctive source and drain antennas electrically isolated from the electron channel. Working at room temperature, it efficiently detects terahertz radiation via self-mixing, with a responsivity (3.6 kV/W) exceptionally high for a III-V device and with a noise (40pW/Hz) just above the thermal limit. Performance improves at 77 K. While the device itself is micrometer-sized, our modeling indicates the asymmetric antennas induce a rather localized (<200 nm) region of strong self-mixing. Thus, a nanometer-scale active region is achieved by design and without recourse to electron-beam lithography.
Metamaterial with mass-stem array in acoustic cavity
Authors: Islam Md Tofiqul , Newaz Golam
Published: January 2012

A vibro-acoustic metamaterial with negative effective mass has been designed and fabricated. This metamaterial consists of an array of wire stems with attached tiny masses in an acoustic cavity. These internal masses contribute to energy absorption near the natural frequencies of the designed structure. This metamaterial damps single resonance of internal mass and has larger mass damping parameter than stiffness damping parameter. Ease of fabrication makes the metamaterial practical for dynamic disturbance mitigation and acoustic attenuation.
Reversal and excitations of a nanoscale magnetic domain by sustained pure spin currents
Authors: Zou Han , Chen Shuhan , Ji Yi
Published: January 2012

Spin-transfer effects induced by pure spin currents are explored in nonlocal spin valves by using sustained injection currents. Compared to pulsed injection currents used in previous experiments, this approach provides persistent spin-transfer torques and preserves the history of the reversal process. A nanoscale domain in a magnetic wire can be switched reversibly by the sustained pure spin currents. In addition, dips in nonlocal spin signal curves are observed at high magnetic fields for only one polarity of the injection currents. This indicates stable-state magnetization precession around the external field driven by the sustained pure spin currents.
Optical microcavities with a thiol-functionalized gold nanoparticle polymer thin film coating
Authors: Shi Ce , Seok Choi Hong , Armani Andrea M.
Published: January 2012

Polymer coatings endow ultra-high-Q dielectric resonators with nonlinear properties, impacting numerous applications. However, minimal research combining microcavities with polymer-nanoparticle coatings to tune or tailor the optical properties of the system has been performed. One challenge is maintaining the high performance of the optical device while in the presence of nanoparticles. In the present work, a toroidal microcavity is coated with a polymethylmethacrylate thin film containing thiol-functionalized gold nanoparticles. The thiol-functionalization ensures that the nanoparticles are uniformly distributed throughout the film. The quality factors of these devices are above 5 × 106 and are in good agreement with the theoretical predictions.
Incorporating C2 into C60 films
Authors: Ulas Seyithan , Strelnikov Dmitry , Weis Patrick , Böttcher Artur , Kappes Manfred M.
Published: January 2012

The material formed by depositing C2− anions onto/into thin C60 films (on graphite) at room temperature has been studied by means of thermal desorption mass spectroscopy, ultraviolet photoionization spectroscopy, atomic force microscopy (AFM), and surface enhanced Raman spectroscopy. As-prepared, C2/C60 films manifest thermal desorption behaviour which differs significantly from pure C60 films. Whereas the latter can be fully sublimed, we observe decomposition of C2/C60 films to a high-temperature-stable material while predominantly C60, C62, and C64 are desorbed in parallel. Deposition of C2− also leads to significantly modified electronic and vibrational properties. Based on DFT model calculations of the Raman spectra, we suggest that as-prepared C2/C60 films contain appreciable amounts of polymeric networks comprising –C2–C60–C2–C60– chains. Detection of sublimed C62 and C64 upon heating implies that thermal decomposition of C2/C60 films involves addition/uptake of C2 units into individual fullerene cages. Correspondingly, annealing films up to various intermediate temperatures results in significant modifications to valence-band UP spectra as well as to surface topographies as imaged by AFM. The novel carbonaceous material obtained by heating to T > 950 K has a finite density of states at the Fermi level in contrast to as-prepared C2/C60. It comprises fused fullerene cages.
Proton-irradiated InAlN/GaN high electron mobility transistors at 5, 10, and 15 MeV energies
Authors: Kim H.-Y. , Lo C. F. , Liu L. , Ren F. , Kim J. , Pearton S. J.
Published: January 2012

InAlN/GaN high electron mobility transistors (HEMTs) grown on SiC substrates were subjected to 5-15 MeV high energy protons with a fixed 5 × 1015 cm−2 fluence. The saturation currents and gate leakage currents of all the proton-irradiated InAlN/GaN HEMTs were degraded. Proton irradiation at lower energy was found to degrade the direct current (DC) current-voltage (I-V) characteristics more severely than higher-energy irradiation, because the energy loss component of the lower energy protons was larger than those of higher-energy protons in the vicinity of the 2-dimensional electron gas conducting channel. Our experimental results were consistent with stopping and range of ions in matter simulation results of the energy deposition profile by the protons.
Actuation and tracking of a single magnetic particle on a chip
Authors: Rinklin Philipp , Krause Hans-Joachim , Wolfrum Bernhard
Published: January 2012

We present the defined actuation of a single magnetic particle on a crossbar array chip. Two orthogonal layers of parallel microwires are used to generate highly localized magnetic field gradients for particle trapping and movement. We introduce an analytical model to simulate the actuation of the particle, which is in precise agreement with the experimentally observed trajectory. The single-particle approach allows us to resolve subtle features of the induced magnetic field distribution. We demonstrate that the actuation strongly depends on the applied current sequence and introduce switching patterns for reliable control of an individual particle.
Cullin-3 regulates late endosome maturation
Authors: Huotari Jatta , Meyer-Schaller Nathalie , Hubner Michaela , Stauffer Sarah , Katheder Nadja , Horvath Peter , Mancini Roberta , Helenius Ari , Peter Matthias
Published: January 2012

Cullin-3 (Cul3) functions as a scaffolding protein in the Bric-a-brac, Tramtrack, Broad-complex (BTB)–Cul3–Rbx1 ubiquitin E3 ligase complex. Here, we report a previously undescribed role for Cul3 complexes in late endosome (LE) maturation. RNAi-mediated depletion of Cul3 results in a trafficking defect of two cargoes of the endolysosomal pathway, influenza A virus (IAV) and epidermal growth factor receptor (EGFR). IAV is able to reach an acidic endosomal compartment, coinciding with LE/lysosome (LY) markers. However, it remains trapped or the capsid is unable to uncoat after penetration into the cytosol. Similarly, activation and subsequent ubiquitination of EGFR appear normal, whereas downstream EGFR degradation is delayed and its ligand EGF accumulates in LE/LYs. Indeed, Cul3-depleted cells display severe morphological defects in LEs that could account for these trafficking defects; they accumulate acidic LE/LYs, and some cells become highly vacuolated, with enlarged Rab7-positive endosomes. Together, these results suggest a crucial role of Cul3 in regulating late steps in the endolysosomal trafficking pathway.
Distinct influences of peptide-MHC quality and quantity on in vivo T-cell responses
Authors: Gottschalk Rachel A. , Hathorn Matthew M. , Beuneu Hélène , Corse Emily , Dustin Michael L. , Altan-Bonnet Grégoire , Allison James P.
Published: January 2012

The strength of T-cell receptor (TCR) stimulation and subsequent T-cell response depend on a combination of peptide-major histocompatibility complex (pMHC) density and potency. By comparing two different pMHC at doses yielding similar proliferation in vivo, we have highlighted unexpected differences in the qualitative and quantitative effects of TCR ligand. Measurements of cytokine sensitivity and two-photon imaging of T cell–dendritic cell (T–DC) interactions reveal discrimination between comparably weak stimuli resulting from either decreased pMHC potency or pMHC density. In addition, TCR-induced genes in broad gene expression profiles segregate into two groups: one that responds to cumulative TCR signal and another that responds to pMHC quality, independent of quantity. These observations suggest that models of TCR ligand discrimination must account for disparate sensitivity of downstream responses to specific influences of pMHC potency.
Context-specific control in the single-prime negative-priming procedure
Authors: D'Angelo Maria C. , Milliken Bruce
Published: January 2012

The current paper examines the applicability of the context-specific control principle to the probe selection dependence of negative-priming effects using the single-prime procedure. In a series of experiments, we highlight the applicability of the context-specific control principle, first by illustrating a key result that implicates the role of context-specific control and challenges the contextual similarity principle. Following this, we show the importance of distinct probe contexts in the single-prime negative-priming procedure and report a novel finding that illustrates a learning effect that can occur within an experimental session. Finally, we test the relation of our novel learning effect to a related learning proposal offered by Frings and Wentura (2006), and we demonstrate that the learning involved in context-specific control is not dependent on contingency learning. Overall, the patterns of results highlight the role of context-sensitive memory in controlling how current perception and action are integrated with prior experience.
Does Temporal Contiguity Moderate Contingency Learning in a Speeded Performance Task?
Authors: Schmidt James R. , De Houwer Jan
Published: January 2012

In four experiments, we varied the time between the onset of distracting nonwords and target colour words in a word–word version of the colour–word contingency learning paradigm. Contingencies were created by pairing a distractor nonword more often with one target colour word than with other colour words. A contingency effect corresponds to faster responses to the target colour word on high-contingency trials (i.e., distractor nonword followed by the target colour word with which it appears most often) than on low-contingency trials (i.e., distractor nonword followed by a target colour word with which it appears only occasionally). Roughly equivalent-sized contingency effects were found at stimulus-onset asynchronies (SOAs) of 50, 250, and 450 ms in Experiment 1, and 50, 500, and 1,000 ms in Experiment 2. In Experiment 3, a contingency effect was observed at SOAs of –50, –200, and –350 ms. In Experiment 4, interstimulus interval (ISI) was varied along with SOA, and learning was equivalent for 200-, 700-, and 1,200-ms SOAs. Together, these experiments suggest that the distracting stimulus does not need to be presented in close temporal contiguity with the response to induce learning. Relations to past research on causal judgement and implications for further contingency learning research are discussed.
Gigerenzer's Evolutionary Arguments against Rational Choice Theory: An Assessment
Authors: Schulz Armin W.
Published: January 2012

I critically discuss a recent innovation in the debate surrounding the plausibility of rational choice theory (RCT): the appeal to evolutionary theory. Specifically, I assess Gigerenzer and colleagues’ claim that considerations based on natural selection show that, instead of making decisions in a RCT-like way, we rely on ‘simple heuristics’. As I try to make clearer here, though, Gigerenzer and colleagues’ arguments are unconvincing: we lack the needed information about our past to determine whether the premises on which they are built are true—and, hence, we cannot tell whether they, in fact, speak against RCT.
Scientific Explanation between Principle and Constructive Theories
Authors: Felline Laura
Published: January 2012

The aim of this article is to analyze the role of the distinction between principle and constructive theories in the question of the explanatory power of special relativity. We show how the distinction breaks down at the explanatory level. We assess Harvey Brown's claim that, as a principle theory, special relativity lacks explanatory power. We argue that this claim is based on an unrealistic picture of the kind of explanations provided by principle (and constructive) theories. Finally, we argue that the structural account of explanation captures the explanatory success of special relativity.
True Lies: Realism, Robustness, and Models
Authors: Odenbaugh Jay
Published: January 2012

In this essay, I argue that uneliminated idealizations pose a serious problem for scientific realism. I consider one method for “de-idealizing” models—robustness analysis. However, I argue that unless idealizations are eliminated from an idealized theory and robustness analysis need not do that, scientists are not justified in believing that the theory is true. I consider one example of modeling from the biological sciences that exemplifies the problem.
Infection Prevention Promotion Program Based on the PRECEDE Model: Improving Hand Hygiene Behaviors among Healthcare Personnel
Authors: Aboumatar Hanan , Ristaino Polly , Davis Richard O. , Thompson Carol B. , Maragakis Lisa , Cosgrove Sara , Rosenstein Beryl , Perl Trish M.
Published: January 2012

Background.

Healthcare-associated infections (HAIs) result in significant morbidity and mortality. Hand hygiene remains a cornerstone intervention for preventing HAIs. Unfortunately, adherence to hand hygiene guidelines among healthcare personnel is poor.

Objective.

To assess short- and long-term effects of an infection prevention promotion program on healthcare personnel hand hygiene behaviors.

Design.

Time series design.

Setting

Our study was conducted at a tertiary care academic center.

Participants.

Hospital healthcare personnel.

Methods.

We developed a multimodal program that included a multimedia communications campaign, education, leadership engagement, environment modification, team performance measurement, and feedback. Healthcare personnel hand hygiene practices were measured via direct observations over a 3-year period by “undercover” observers.

Results.

Overall hand hygiene compliance increased by 2-fold after full program implementation (P<.001), and this increase was sustained over a 20-month follow-up period (P< .001). The odds for compliance with hand hygiene increased by 3.8-fold in the 6 months after full program implementation (95% confidence interval, 3.53–4.23; P< .001), and this increase was sustained. There was even a modest increase at 20 months of follow up. Hand hygiene compliance increased among all disciplines and hospital units. Hand hygiene compliance increased from 35% in the first 6 months after program initiation to 77% in the last 6 months of the study period among nursing providers (P<.001), from 38% to 62% among medical providers (P<.001), and from 27% to 75% among environmental services staff (P<.001).

Conclusions.

Implementation of the infection prevention promotion program was associated with a significant and sustained increase in hand hygiene practices among healthcare personnel of various disciplines.

Infect Control Hosp Epidemiol 2012;33(2):144-151
Clarithromycin form I determined by synchrotron X-ray powder diffraction
Authors: Noguchi Shuji , Miura Keiko , Fujiki Sadahiro , Iwao Yasunori , Itai Shigeru
Published: January 2012

The structure of the metastable form I polymorph of the macrolide antibiotic clarithromycin, C38H69NO13, was determined by a powder diffraction method using synchrotron radiation. The space group of form I isP21212. The initial model was determined by a molecular replacement method using the structure of clarithromycin form 0 as a search model, and the final structure was obtained through Rietveld refinements. In the form I crystal structure, the clarithromycin molecules are aligned parallel along theaaxis in a head-to-tail manner with intermolecular hydrogen bonds between the hydroxy O atoms. The dimethylamine groups of the clarithromycin molecule interdigitate between neighbouring head-to-tail clarithromycin alignments. The novel crystal packing found in form I provides a mechanism that describes the transformation of form 0 to form I.
An order–disorder phase transition in the structure of C60·4benzene
Authors: Olmstead Marilyn M. , Balch Alan L. , Lee Hon Man
Published: January 2012

A reversible, broad, order–disorder phase transition in the structure of C60·4benzene has been observed to take place with an inflection point at 134 K. In the low-temperature structure fullerene disorder is removed, although the average atomic displacement parameters differ for the two C60 molecules in the asymmetric unit. Some benzene disorder persists, even at 13 K.
High-precision absolute lattice parameter determination of SrTiO3, DyScO3 and NdGaO3 single crystals
Authors: Schmidbauer Martin , Kwasniewski Albert , Schwarzkopf Jutta
Published: January 2012

The lattice parameters of three perovskite-related oxides have been measured with high precision at room temperature. An accuracy of the order of 10−5 has been achieved by applying a sophisticated high-resolution X-ray diffraction technique which is based on the modified Bond method. The results on cubic SrTiO3 [a = 3.905268 (98) Å], orthorhombic DyScO3 [a = 5.442417 (54), b = 5.719357 (52) and c = 7.904326 (98) Å], and orthorhombic NdGaO3 [a = 5.428410 (54), b = 5.498407 (55) and c = 7.708878 (95) Å] are discussed in view of possible systematic errors as well as non-stoichiometry in the crystals.
Effects of nonylphenol on vitellogenin synthesis in adult males of the spotted ray Torpedo marmorata
Authors: Del Giudice G. , Prisco M. , Agnese M. , Verderame M. , Rosati L. , Limatola E. , Andreuccetti P.
Published: January 2012

The aim of this investigation was to assess the effects of nonylphenol (NP), an oestrogen‐like environmental pollutant, on the vitellogenin (VTG) synthesis in adult males of the aplacental viviparous cartilaginous fish Torpedo marmorata. The VTG recovery in males is considered a biomarker of xeno‐oestrogenic pollution as this lipophosphoglycoprotein is physiologically induced by oestrogens only in females of oviparous and ovoviparous vertebrates. Using in situ hybridization and immunohistochemistry, T. marmorata males injected with nonylphenol showed the presence of VTG in the liver and the kidney. In particular, vtg messenger (m)RNA and VTG protein were expressed in the liver, whereas in the kidney cells only the presence of VTG was recorded. By contrast, no expression for VTG was detected in the testis. These results demonstrate that in T. marmorata NP induces the expression of vtg only in the liver; the presence of VTG in the kidney and its absence in the testis are discussed.
Leadership and transitions: maintaining the science in complexity and complex systems
Authors: Sturmberg Joachim P. , Martin Carmel M.
Published: January 2012

It is the ‘moral compass’, however subtle, that underpins leadership. Leadership, meaning showing the way, demands as much conviction as gentile diplomacy in the discourse with supporters and detractors. In particular, leadership defends the goal by safeguarding its principles from its detractors. The authors writing in the Forum on Complexity in Medicine and Healthcare since its inception are leaders in an intellectual transition to complex systems thinking in medicine and health.
Understanding health system reform – a complex adaptive systems perspective
Authors: Sturmberg Joachim P. , O'Halloran Di M. , Martin Carmel M.
Published: January 2012

Background Everyone wants a sustainable well‐functioning health system. However, this notion has different meaning to policy makers and funders compared to clinicians and patients. The former perceive public policy and economic constraints, the latter clinical or patient‐centred strategies as the means to achieving a desired outcome.

Design Theoretical development and critical analysis of a complex health system model.

Results and conclusions We introduce the concept of the health care vortex as a metaphor by which to understand the complex adaptive nature of health systems, and the degree to which their behaviour is predetermined by their ‘shared values’ or attractors. We contrast the likely functions and outcomes of a health system with a people‐centred attractor and one with a financial attractor. This analysis suggests a shift in the system's attractor is fundamental to progress health reform thinking.
Armillaria ostoyae associated with dying 60‐year‐old Scots pines in northern Turkey
Authors: Lehtijärvi A. , Doğmuş ‐Lehtijärvi H. T. , Aday A. G.
Published: January 2012

We investigated an Armillaria root disease centre in a 60‐year‐old, naturally regenerated Pinus sylvestris stand located at 1250 m altitude in Sinop province in northern Turkey. Based on sequence analysis of the internal transcribed spacer region of the rDNA, the mycelial fans sampled from the infected trees were Armillaria ostoyae. Multilocus genotyping indicated that the fans belonged to a single genet, at least 0.2 ha in size. Drought as a predisposing factor is discussed. The study area received 50–70 and 25–50% of the normal precipitation in May, June and August in 2009 and in August and September in 2010, respectively. Moreover, earlier excavation work to prepare a forest road had probably disrupted the water table in the affected stand.
Tree chitinases – stress‐ and developmental‐driven gene regulation
Authors: Veluthakkal R. , Sundari B. Karpaga Raja , Dasgupta M. Ghosh
Published: January 2012

In recent years, a considerable number of studies have harnessed the power of genomics to decipher the role of pathogenesis‐related (PR) proteins in plant defence against various biotic and abiotic stresses. Chitinases are PR antifungal proteins expressed constitutively at low levels in plants and induced during biotic pressures and are demonstrated to be involved in the plant defence responses. Remarkable induction of chitinase enzymes by various abiotic agents (salicylic acid, jasmonic acid, ethylene and ozone) and biotic components (pathogens, insect pest, fungal cell wall components and oligosaccharides) is well demonstrated in plants. Several reviews on plant chitinase expression during host–pathogen interaction are available for annual species, whilst reports of their expression in tree species are limited to a few woody perennials: Populus, Pinus, Picea, Eucalyptus, Castanea and Pseudotsuga. The aim of this paper is to review the induction of chitinase during various stresses and developmental processes in forest tree species.
Paraneoplastic neurological and hematological syndromes associated with prostate cancer
Authors: Gakiya Munehisa , Naka Hidekatsu , Saito Seiichi
Published: January 2012

Paraneoplastic neurological syndromes are defined as the remote effects of cancer on the nervous system. Here we report a 68‐year‐old man who initially presented with worsening paresthesia in the lower extremities. Although the culprit lesion remained to be identified, he coincidentally had diagnosis of prostate cancer by an annual prostate‐specific antigen examination. Leukocytosis and elevated granulocyte colony‐stimulating factor in serum were also detected. Neurological symptoms and leukocytosis improved after initiation of androgen‐deprivation therapy followed by external beam radiotherapy. A total of 9 months after treatment, the patient showed no evidence of cancer recurrence or neurological signs. Paraneoplastic neurological syndromes are rare in prostate cancer and therefore have received little attention. We should be aware that when paraneoplastic neurological syndromes occur, they usually occur as the first sign of or during progression of prostate cancer. Furthermore, we should take into account the existence of malignancy when the cause of neurological symptoms cannot be specified.
Pheochromocytoma crisis caused by Campylobacter fetus
Authors: Abe Ichiro , Nomura Masatoshi , Watanabe Makiko , Shimada Shingo , Kohno Michiko , Matsuda Yayoi , Adachi Masahiro , Kawate Hisaya , Ohnaka Keizo , Takayanagi Ryoichi
Published: January 2012

Pheochromocytoma crisis is a life‐threatening endocrine emergency associated with symptoms of excess release of catecholamines. It might present spontaneously or be unmasked by triggers including trauma, surgery and certain medications that provoke catecholamine release by tumors. Here we report a case of pheochromocytoma crisis associated with abscess formation in the tumor and bacteremia of Campylobacter fetus, which was successfully treated with antibiotics and a surgical resection. This case appears to be the first reported case in the literature of abscess formation by C. fetus in pheochromocytoma, leading to catecholamine crisis.
Prospective trial comparing transrectal ultrasonography and transurethral seminal vesiculoscopy for persistent hematospermia
Authors: Xing Changyong , Zhou Xiaomei , Xin Lei , Hu Hongzhen , Li Liping , Fang Jingchuan , Liu Zhiyong
Published: January 2012

Objective:  To compare the diagnostic yield of transrectal ultrasonography and transurethral seminal vesiculoscopy in patients with persistent hematospermia, and to determine the advantages and disadvantages of both modalities.

Methods:  We prospectively enrolled 106 patients with persistent hematospermia of mean duration 20.5 months. All patients were evaluated by both transrectal ultrasonography and transurethral seminal vesiculoscopy after excluding definite etiological lesions beyond the reproductive duct system. The diagnostic yield and other technical parameters of both modalities were compared.

Results:  Final diagnoses were made in 93 patients (87.7%), with transrectal ultrasonography and transurethral seminal vesiculoscopy showing overall diagnostic yields of 45.3% and 74.5%, respectively (P < 0.001). The diagnostic yield of combining transrectal ultrasonography and transurethral seminal vesiculoscopy was significantly higher than that of each modality alone (both P < 0.001). Of the 114 findings of diagnostic value, the most frequent was calculus (47.4%, n = 54), followed by obstruction/stricture (37.7%, n = 43), cyst (8.8%, n = 10), dysplasia (3.5%, n = 4), polyp (1.8%, n = 2) and benign mass (0.9%, n = 1). Transurethral seminal vesiculoscopy showed significant superiority in detecting calculi and obstruction/stricture. Hematospermia disappeared in 95.3% (101/106) of all patients and in 97.6% (83/85) of patients receiving transurethral seminal vesiculoscopy therapy during follow up. No major adverse effects occurred during and after examination.

Conclusions:  The diagnostic yield of transurethral seminal vesiculoscopy for persistent hematospermia was significantly superior to that of transrectal ultrasonography, especially in lesions diagnosed with calculi and obstruction/stricture. Combining both modalities might provide extra benefits for patients with persistent hematospermia.