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Complexity theory

David N George
In four experiments, participants' performance on a variety of nonlinear patterning discriminations was assessed using a predictive learning task and visual patterns. Between groups, the similarity of the stimuli that composed these visual patterns was manipulated. When the stimuli were of low similarity, participants' performance was consistent with the predictions of one version of Pearce's (1987, 1994, 2002) configural theory of learning (Kinder & Lachnit, 2003); they were better able to discriminate between different patterns when they shared few, rather than many, stimuli...
April 2018: Journal of Experimental Psychology. Animal Learning and Cognition
Johannes Fiedler, Clas Persson, Mathias Boström, Stefan Yoshi Buhmann
Dispersion forces, especially van der Waals forces as interactions between neutral and polarisable particles act at small distances between two objects. Their theoretical origin lies in the electromagnetic interaction between induced dipole moments caused by the vacuum fluctuations of the ground-state electromagnetic field. The resulting theory well describes the experimental situation in the limit of the point dipole assumption. At smaller distances, where the finite size of the particles has to be taken into account, this description fails and has to be corrected by higher orders of the multipole expansion, such as quadrupole moments and so on...
April 23, 2018: Journal of Physical Chemistry. A
Vsevolod A Bolotov, Konstantin A Kovalenko, Denis G Samsonenko, Xue Han, Xinran Zhang, Gemma L Smith, Laura McCormick, Simon J Teat, Sihai Yang, Matthew J Lennox, Alice Henley, Elena Besley, Vladimir P Fedin, Danil N Dybtsev, Martin Schröder
The complex [Zn2 (tdc)2 dabco] (H2 tdc = thiophene-2,5-dicarboxylic acid; dabco = 1,4-diazabicyclooctane) shows a remarkable increase in carbon dioxide (CO2 ) uptake and CO2 /dinitrogen (N2 ) selectivity compared to the nonthiophene analogue [Zn2 (bdc)2 dabco] (H2 bdc = benzene-1,4-dicarboxylic acid; terephthalic acid). CO2 adsorption at 1 bar for [Zn2 (tdc)2 dabco] is 67.4 cm3 ·g-1 (13.2 wt %) at 298 K and 153 cm3 ·g-1 (30.0 wt %) at 273 K. For [Zn2 (bdc)2 dabco], the equivalent values are 46 cm3 ·g-1 (9...
April 23, 2018: Inorganic Chemistry
Amandine Lassalle, Nicole R Zürcher, Carlo A Porro, Francesca Benuzzi, Loyse Hippolyte, Eric Lemonnier, Jakob Åsberg Johnels, Nouchine Hadjikhani
The circumstances under which empathy is altered in ASD remain unclear, as previous studies did not systematically find differences in brain activation between ASD and controls in empathy-eliciting paradigms, and did not always monitor whether differences were primarily due to ASD "per se", or to conditions overlapping with ASD, such as alexithymia and anxiety. Here, we collected fMRI data from 47 participants (22 ASD) viewing pictures depicting hands and feet of unknown others in painful, disgusting, or neutral situations...
April 23, 2018: Social Neuroscience
Daniel C Ashley, Elena Jakubikova
Twisting motions in six-coordinate trischelate transition-metal complexes have long been recognized as a potential reaction coordinate for nondissociative racemization by changing the coordination geometry from octahedral to trigonal prismatic in the transition state. These pathways have been previously established as the Bailar twist (conversion to D3 h symmetry) and the Ray-Dutt twist (conversion to C2 v symmetry). Twisting motions have been shown to be associated with changes in spin state and are therefore of relevance not only to thermal isomerization pathways but also to spin-crossover (SCO) and intersystem crossing mechanisms...
April 23, 2018: Inorganic Chemistry
Y Fu, E McNichol, K Marczewski, S José Closs
Supporting patients in forming partnerships with health professionals is the key of effective self-management. This study aimed to explore the nature of patient-professional partnerships and its related factors that create facilitators and barriers to patients' self-management ability. A constructivist grounded theory approach was undertaken. Three main themes emerged: interaction and communication, integrated care, and service and system. A theoretical model was generated that posits effective communication, individualized integrated care, and high-quality service as key influences on the successful development of patient-professional partnerships and patients' ability to self-manage...
April 1, 2018: Qualitative Health Research
Siyu Hu, Wen Xiao, Weiwei Yang, Ji Yang, Yarong Fang, Juxia Xiong, Zhu Luo, Hongtao Deng, Yanbing Guo, Lizhi Zhang, Jun Ding
The activation of molecular oxygen (O2 ) is extremely crucial in heterogeneous oxidations for various industrial applications. Here, a charge-transfer complex CuTCNQ nanowires array (CuTCNQ NWs) grown on the copper foam was first reported to show CO catalytic oxidation activity at temperature below 200°C with the activated O2 as an oxidant. The molecular O2 was energetically activated over the Cu (I) mediated C≡N bond with a lower energy of -1.167 eV, and preferentially reduced to •O2 - through one-electron transfer during the activation process by density functional theory (DFT) calculations and Electron paramagnetic resonance (EPR)...
April 23, 2018: ACS Applied Materials & Interfaces
Zai-Quan Xu, Christopher Elbadawi, Toan Trong Tran, Mehran Kianinia, Xiuling Li, Daobin Liu, Timothy B Hoffman, Minh Nguyen, Sejeong Kim, James H Edgar, Xiaojun Wu, Li Song, Sajid Ali, Mike Ford, Milos Toth, Igor Aharonovich
Artificial atomic systems in solids are becoming increasingly important building blocks in quantum information processing and scalable quantum nanophotonic networks. Amongst numerous candidates, 2D hexagonal boron nitride has recently emerged as a promising platform hosting single photon emitters. Here, we report a number of robust plasma and thermal annealing methods for fabrication of emitters in tape-exfoliated hexagonal boron nitride (hBN) crystals. A two-step process comprising Ar plasma etching and subsequent annealing in Ar is highly robust, and yields an eight-fold increase in the concentration of emitters in hBN...
April 23, 2018: Nanoscale
Carlo Gatti, Giovanni Macetti, Russell J Boyd, Chérif F Matta
The source function (SF) decomposes the electron density at any point into contributions from all other points in the molecule, complex, or crystal. The SF "illuminates" those regions in a molecule that most contribute to the electron density at a point of reference. When this point of reference is the bond critical point (BCP), a commonly used surrogate of chemical bonding, then the SF analysis at an atomic resolution within the framework of Bader's Quantum Theory of Atoms in Molecules returns the contribution of each atom in the system to the electron density at that BCP...
April 21, 2018: Journal of Computational Chemistry
Xiaomin Dou, Gui-Chang Wang, Mengqiang Zhu, Fudong Liu, Wei Li, Dinesh Mohan, Charles U Pittman
The Fe-Zr binary oxide adsorbents have higher arsenic adsorptive capacities than either iron oxide or zirconium oxide alone, indicating a strong synergistic effect exists between Fe and Zr oxides. However, no generally accepted in-depth explanations have been reached on the origin of this better performance. In the present study, the component phases, the active surface sites, the structure of the adsorbed As(V) surface species, and the mechanism of the synergistic effect, were investigated and elucidated using multiple advanced experimental techniques combined with quantum chemical calculations...
April 10, 2018: Journal of Hazardous Materials
Megan E Gonzalez, Juergen Eckert, Adelia J A Aquino, Bill Poirier
Progress in the hydrogen fuel field requires a clear understanding and characterization of how materials of interest interact with hydrogen. Due to the inherently quantum mechanical nature of hydrogen nuclei, any theoretical studies of these systems must be treated quantum dynamically. One class of material that has been examined in this context are dihydrogen complexes. Since their discovery by Kubas in 1984, many such complexes have been studied both experimentally and theoretically. This particular study examines the rotational dynamics of the dihydrogen ligand in the Fe(H)2 (H2 )(PEtPh2 )3 complex, allowing for full motion in both the rotational degrees of freedom and treating the quantum dynamics (QD) explicitly...
April 21, 2018: Journal of Chemical Physics
M E Sánchez Vergara, R Salcedo, Bertha Molina, R Carrera-Téllez, J R Álvarez-Bada, A Hernández-García, V Gómez-Vidales
The present study reports the doping of a semiconducting molecular material through the formation of hydrogen bonds between the macrocycle Cu(II)(TAAB) and the electronic acceptor TCNQ. According to density functional theory (DFT) calculations and electron paramagnetic resonance (EPR) analysis, the doped compound has the shape of a distorted square pyramid, with four nitrogen atoms in the equatorial position and the apical oxygen atom from the water ligands. These water molecules can generate strong hydrogen bonds with TCNQ and the TAAB metallic complex...
April 11, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Sabina Podlewska, Rafał Kafel, Enza Lacivita, Grzegorz Satała, Albert J Kooistra, Márton Vass, Chris de Graaf, Marcello Leopoldo, Andrzej J Bojarski, Stefan Mordalski
Identifying desired interactions with a target receptor is often the first step when designing new active compounds. However, attention should also be focused on contacts with other proteins that result in either selective or polypharmacological compounds. Here, the search for the structural determinants of selectivity between selected serotonin receptor subtypes was carried out. Special attention was focused on 5-HT7 R and the cross-interactions between its ligands and the 5-HT1A R, 5-HT1B R, 5-HT2A R, 5-HT2B R, and 5-HT6 R subtypes...
April 6, 2018: European Journal of Medicinal Chemistry
Sean McDowell, Amyand David Buckingham
A computational study was undertaken for the model complexes H2X…YF and (CH3)2X…YF (X = O, S, Se; Y = F, Cl, H), and H3X'…YF and (CH3)3X'…YF (X' = N, P, As), at the MP2/6-311++G(d,p) level of theory. For H2X…YF and H3X'…YF, noncovalent interactions dominate the binding in order of increasing YF dipole moment, except for H3As…F2, and possibly H3As…ClF. However, for the methyl-substituted complexes (CH3)2X…YF and (CH3)3X'…YF the binding is especially strong for the complexes containing F2, implying significant chemical bonding between the interacting molecules...
April 20, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Kristina Schildmeijer, Carolina Wannheden, Lina Nilsson, Oscar Frykholm, Amanda Hellström, Maria Flink, Mirjam Ekstedt
In previous research we have learned that patients with chronic or complex diseases often experience difficulties when transitioning from hospital care to self-care in their home. We address these difficulties by developing an eHealth tool for patients - ePATH (electronic Patient Activation in Treatment at Home) - intended to empower each patient to manage their individual situation. We have employed a user-centered design process involving both patients and healthcare personnel to specify the content and functionality of ePATH...
2018: Studies in Health Technology and Informatics
Jan Vícha, Stanislav Komorovsky, Michal Repisky, Radek Marek, Michal Straka
The importance of relativistic effects on the NMR parameters in heavy-atom (HA) compounds, particularly the SO-HALA (Spin-Orbit Heavy Atom on the Light Atom) effect on NMR chemical shifts, has been known for about 40 years. Yet, a general correlation between the electronic-structure and SO-HALA effect have been missing. By analyzing 1H NMR chemical shifts of the 6th-period hydrides (Cs-At) we discovered general electronic-structure principles and mechanisms that dictate the size and sign of the SO-HALA NMR chemical shifts...
April 20, 2018: Journal of Chemical Theory and Computation
Hans-Joerg Ehni, Selma Kadi, Maartje Schermer, Sridhar Venkatapuram
Gerontologists have proposed different concepts for ageing well such as 'successful ageing', 'active ageing', and 'healthy ageing'. These conceptions are primarily focused on maintaining health and preventing disease. But they also raise the questions: what is a good life in old age and how can it be achieved? While medical in origin, these concepts and strategies for ageing well also contain ethical advice for individuals and societies on how to act regarding ageing and old age. This connection between gerontology and ethics is overlooked by both schools of thought...
May 2018: Bioethics
S Liu, D Baugh, K Motobayashi, X Zhao, S V Levchenko, S Gawinkowski, J Waluk, L Grill, M Persson, T Kumagai
Anharmonicity plays a crucial role in hydrogen transfer reactions in hydrogen-bonding systems, which leads to a peculiar spectral line shape of the hydrogen stretching mode as well as highly complex intra/intermolecular vibrational energy relaxation. Single-molecule study with a well-defined model is necessary to elucidate a fundamental mechanism. Recent low-temperature scanning tunnelling microscopy (STM) experiments revealed that the cis ↔ cis tautomerization in a single porphycene molecule on Cu(110) at 5 K can be induced by vibrational excitation via an inelastic electron tunnelling process and the N-H(D) stretching mode couples with the tautomerization coordinate [Kumagai et al...
April 20, 2018: Physical Chemistry Chemical Physics: PCCP
Rui Jin, Kui-Jun Zhao, Gui-Ming Guo, Bing Zhang, Yu-Guang Wang, Chun-Miao Xue, Yi-Heng Yang, Li-Xia Wang, Guo-Hui Li, Jin-Fa Tang, Li-Xing Nie, Xiang-Lin Zhang, Ting-Ting Zhao, Yi Zhang, Can Yan, Suo-Zhong Yuan, Lu-Lu Sun, Xing-Zhong Feng, Dan Yan
With the growth of number of Chinese patent medicines and clinical use, the rational use of Chinese medicine is becoming more and more serious. Due to the complexity of Chinese medicine theory and the uncertainty of clinical application, the prescription review of Chinese patent medicine always relied on experience in their respective, leading to the uncontrolled of clinical rational use. According to the traditional Chinese medicine (TCM) theory and characteristics of the unique clinical therapeutics, based on the practice experience and expertise comments, our paper formed the expert consensus on the prescription review of Chinese traditional patent medicine for promoting the rational use of drugs in Beijing...
March 2018: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
Morten Bonde, Claus Bossen, Peter Danholt
This article analyses an experiment into healthcare governance in Denmark inspired by principles of value-based health care and intended to re-orient the focus of healthcare governance from 'productivity' to 'value for the patient'. The region in charge of the experiment exempted nine hospital departments from activity-based financing and accountability based on diagnosis-related groups, which allegedly incentivised hospitals in 'perverse' and counterproductive ways. Instead, the departments were to develop new indicators from their local practices to support and account for quality and value for the patient...
April 19, 2018: Sociology of Health & Illness
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