Unusual Scaling Research Articles

Signature of an antiferromagnetic metallic ground state in heavily electron-doped Sr2FeMoO6

Sr${}_{2}$FeMoO${}_{6}$ is a well-known double perovskite with exciting high-temperature magnetic properties. Through various magnetic and spectroscopic measurements, we collect compelling evidence here that this compound can be driven into a rare three-dimensional antiferromagnetic metallic state by heavy electron doping (70$%$ Sr${}^{2+}$ substitution by La${}^{3+}$). Moreover, local structural study of these Sr${}_{2\ensuremath{-}x}$La${}_{x}$FeMoO${}_{6}$ (1.0 $\ensuremath{\le}x\ensuremath{\le}$ 1.5) compounds reveals unusual atomic scale phase distribution in terms of La,Fe- and Sr,Mo-rich regions driven by strong La-O covalency, a phenomenon hitherto undisclosed in double perovskites. The general trend of our findings is in agreement with theoretical calculations carried out on realistic structures having local chemical fluctuations, which reconfirms the relevance of the kinetic-energy-driven magnetic model.

LaSrVMoO6: A case study forA-site covalency-driven local cationic order in double perovskites

An unusual atomic scale chemical fluctuation in LaSrVMoO${}_{6}$, in terms of narrow patches of La,V and Sr,Mo-rich phases, has been probed in detail to understand the origin of such a chemical state. Exhaustive tuning of the equilibrium synthesis parameters showed that the extent of phase separation can never be melted down below a unit cell dimension making it impossible to achieve the conventional $B$-site ordered structure, which establishes that the observed ``inhomogeneous'' patchlike structure with minimum dimension of few angstroms is a reality in LaSrVMoO${}_{6}$. Therefore another type of local chemical order, hitherto unknown in double perovskites, gets introduced here. X-ray diffraction, electron microscopy elemental mapping, magnetic, and various spectroscopic studies have been carried out on samples, synthesized under different conditions. These experimental results in conjunction with ab initio electronic structure calculation revealed that it is the energy stability, gained by typical La-O covalency as in LaVO${}_{3}$, that leads to the preferential La,V and Sr,Mo ionic proximity, and the consequent patchy structure.

Literatures at the intersections of national territories: Iranian-Azerbaijani ethnic entrepreneurs in a transnational historical space

This article is an attempt to explore the territoriality of languages in the context of ethno-national mobilizations. It maps the transnational interplay between linguistic spaces that overlap national frameworks. This makes it possible to scrutinize the horizontal and vertical differentiation processes that contribute to the definition of a distinctive literary field. In order to study these processes, we favor a strong empirical anchorage by referring to the notion of transnational historical space, defined as a configuration which covers both spatial and temporal dimensions, bringing territories into contact and linking various temporalities. Our case presents a large geographic space formed by Turkey, the Republic of Azerbaijan, and Iranian Azerbaijan. This unusual scale of analysis helps in understanding how ethnic entrepreneurs can capitalize symbolic resources in their strategies to make their ethnic idiom into a national language and to invest the political field with ethnonational claims.

The unusual cover of the armoured scale Cryptaspidiotus barbusano (Lindinger) (Hemiptera: Diaspididae: Aspidiotinae) with comments on the scale covers of other Diaspididae

Cryptaspidiotus barbusano (Lindinger 1908) is an endemic species of the Canary Islands, only known on Apollonias barbujana (Lauraceae), a plant growing in the “Laurisilva” or laurel forest, in several Macaronesian islands. Recently C. barbusano was collected on Heberdenia excelsa (Myrsinaceae), a new host plant and family, in the Jardín Botánico Canario Viera y Clavijo, Las Palmas, Gran Canaria. The recent collection of C. barbusano gives us the opportunity to redescribe its unusual adult female scale cover. The truncate cone-shaped scale cover and its peculiar reflexed exit tunnel for crawlers, with microscopic details of this rare species, are described and illustrated. The shape of the exit tunnel is discussed and the scale cover is compared with scale covers of several other diaspidid species. Finally, this study shows that C. barbusano is not a pupillarial species as formerly described.

The 5-Dimensional Personality Test (5DPT): Relationships With Two Lexically Based Instruments and the Validation of the Absorption Scale

Although intended to assess vulnerability factors associated with psychopathology, the 5-Dimensional Personality Test (5DPT) shows at least a superficial similarity to instruments that adhere to the lexical tradition in personality psychology. To investigate to which extent this similarity goes, this article compares the 5DPT with 2 lexically based measures, the NEO–Five Factor Inventory and the HEXACO–Personality Inventory–Revised. Moreover, as the NEO Openness to Experience construct demonstrates little relationship with maladaptive personality, whereas the 5DPT Absorption factor was hypothesized to underlie the emergence of positive schizotypic symptoms and related phenomena, the 5DPT was also correlated with the Schizotypic Syndrome Questionnaire (SSQ), the Creative Experiences Questionnaire, Thalbourne's Transliminality Scale, the Launay–Slade Hallucination Scale, and the OLIFE–Unusual Experiences scale. On examining the correlations between the various instruments, it was ascertained (a) that there is no need to extend the theory-informed 5DPT with a 6th dimension similar to the HEXACO factor Honesty–Humility, (b) that the 5DPT dimensions were found on average to share only a moderate amount of variance with the Five-factor model/Big Five factors, and (c) that the 5DPT Absorption scale turned out as anticipated to correlate with the positive symptom scales of the SSQ, as well as with the remaining criterion scales that measure similar constructs.

Bifurcation structure of the [formula omitted]-type period-doubling transition

The period-doubling transition to chaos along the edge of an Arnold tongue is known to display unusual organization and scaling behavior (Kuznetsov et al. (2005) [7]). It is also known that forced period-doubling systems may be associated with the appearance of so-called period-doubled tori (Arneodo et al. (1983) [15]). Using the Rössler system as an example, we present a detailed analysis of the bifurcation structure associated with the forcing of a three-dimensional period-doubling system. We explain how this structure is related to the recently discovered phenomenon of multi-layered tori and discuss different bifurcation scenarios that transform a resonance torus into a period-doubled ergodic torus. Similar bifurcation phenomena have recently been observed in a biologically relevant model of kidney blood flow regulation in response to fluctuations in arterial pressure.

Learning from one another? International policy "emulation" and university-industry technology transfer

Cross-border emulation of economic and technology policies among industrial-economy governments has become common in recent years, and spans policies ranging from intellectual property rights to collaborative R&D. Recent initiatives by a number of industrial-economy governments suggest considerable interest in emulating the Bayh--Dole Act of 1980, a piece of legislation that is widely credited with stimulating significant growth in university--industry technology transfer and research collaboration in the United States. I examine the effects of Bayh--Dole on university--industry collaboration and technology transfer in the United States, emphasizing the lengthy history of both activities prior to 1980 and noting the extent to which these activities are rooted in the incentives created by the unusual scale and structure (by comparison with Western Europe or Japan) of the US higher education system. Efforts at emulation of the Bayh--Dole policy by other governments are likely to have modest success at best without greater attention to the underlying structural differences among the higher education systems of these nations. Copyright 2011 The Author 2011. Published by Oxford University Press on behalf of Associazione ICC. All rights reserved., Oxford University Press.

Holographic Roberge Weiss transitions II: Defect theories and the Sakai Sugimoto model

We extend the work of Aarts et al., including an imaginary chemical potential for quark number into the Sakai-Sugimoto model and codimension k defect theories. The phase diagram of these models are a function of three parameters, the temperature, chemical potential and the asymptotic separation of the flavour branes, related to a mass for the quarks in the boundary theories. We compute the phase diagrams and the pressure due to the flavours of the theories as a function of these parameters and show that there are Roberge-Weiss transitions in the high temperature phases, chiral symmetry restored for the Sakai-Sugimoto model and deconfined for the defect models, while at low temperatures there are no Roberge-Weiss transitions. In all the models we consider the transitions between low and high temperature phases are first order, hence the points where they meet the Roberge-Weiss lines are triple points. The pressure for the defect theories scales in the way we expect from dimensional analysis while the Sakai-Sugimoto model exhibits unusual scaling. We show that the models we consider are analytic in \mu^2 when \mu^2 is small.

Unusual Scaling in the Rheology of Branched Wormlike Micelles Formed by Cetyltrimethylammonium Bromide and Sodium Oleate

Natural fatty acids such as sodium oleate form highly viscous supramolecular complexes with long-chain cationic surfactants through cooperative self-assembly. Here we report the rheological behavior of linear and branched wormlike micelles formed in mixtures of cetyltrimethylammonium bromide (CTAB) and sodium oleate (NaOL). Addition of sodium oleate induces an increase in the axial ratio of the mixed micelles. At a constant mole fraction of the mixture, an increase in total surfactant concentration leads to a transition from linear to branched micelles. Both linear and branched micelles impart viscoelastic behavior to the fluid, and the low-frequency data can be approximated to the Maxwell model. Scaling of the rheological parameters of CTAB-NaOL catanionic mixtures, as a function of concentration, employing dynamic rheological measurements has been determined and compared with the predictions of existing scaling laws. The structural transition from linear micelles to the branched micelles in the CTAB-NaOL micellar system greatly influences the scaling behavior of shear modulus. The scaling exponent is lower for the branched micelles compared to linear micelles, analogous to those of linear and branched polymer melts. The structural evolution is probed by light scattering and small-angle neutron scattering measurements as well.

Deterministic aperiodic nanostructures for photonics and plasmonics applications

AbstractThis review focuses on the optical properties and device applications of deterministic aperiodic media generated by mathematical rules with spectral features that interpolate in a tunable fashion between periodic crystals and disordered random media. These structures are called Deterministic Aperiodic Nano Structures (DANS) and can be implemented in different materials (linear and nonlinear) and physical systems as diverse as dielectric multilayers, optical gratings, photonic waveguides and nanoparticle arrays. Among their distinctive optical properties are the formation of multi‐fractal bandgaps and characteristic optical resonances, called critical modes, with unusual localization, scaling and transport properties. The goal of the paper is to provide a detailed review of the conceptual foundation and the physical mechanisms governing the complex optical response of DANS in relation to the engineering of novel devices and functionalities. The discussion will mostly focus on passive and active planar structures with enhanced light‐matter coupling for photonics and plasmonics technologies.

Sharp Phase Transitions in a Small Frustrated Network of Trapped Ion Spins

Sharp quantum phase transitions typically require a large system with many particles. Here we show that, for a frustrated fully connected Ising spin network represented by trapped atomic ions, the competition between different spin orders leads to rich phase transitions whose sharpness scales exponentially with the number of spins. This unusual finite-size scaling behavior opens up the possibility of observing sharp quantum phase transitions in a system of just a few trapped ion spins.

Schizotypy and emotional memory

Background Emotional dysfunction is a core feature of psychotic disorders. One expression of such dysfunction is a reduction of the emotion-induced enhancement of memory which is normally found in healthy individuals. Less severe disruption of emotional processing may also be present in individuals prone to ‘unusual’ psychosis-like experiences. In this study we investigate voluntary declarative (i.e. explicit or episodic) emotional memory performance, primarily in relation to positive schizotypy (as measured by the unusual experiences scale of the O-LIFE). The effect of negative schizotypy (introvertive anhedonia scale of the O-LIFE) was also explored. We hypothesized that schizotypal individuals (scoring highly on Unusual Experiences) would show reduced memory enhancement. Methods One hundred and two healthy participants viewed a narrated slide-show containing neutral and negative emotional content. They rated the story on a number of affective dimensions and completed a variety of trait measures, including a multi-dimensional measure of schizotypy. Seven days later, a memory test was performed and frequency of involuntary memories related to the slide-show assessed. Results The voluntary declarative emotional memory advantage in recall seen in low scorers (25%ile) on unusual experiences was absent in high scorers (75%ile), despite greater subjective fearfulness and emotionality in that group. However, the high scoring group did report experiencing more involuntary memories related to the story. There was no effect of negative schizotypy on declarative emotional memory. Conclusions The emotional memory difficulties seen in studies of schizophrenia may extend to those with a vulnerability to positive psychosis-like experiences. This vulnerability may be expressed in both voluntary declarative – as well as involuntary – emotional memory performance.

Non-adiabatic quench dynamics near anisotropic quantum critical point

We study non-equilibrium dynamics induced by a quench of a parameter near a quantum phase transition in the Kitaev model. On the basis of an exact solution for the time-dependent Schrödinger equation, we show that the density of excitations and residual energy after a quench scale with a quench rate τ−1 as τ−3/4 and τ−5/4 respectively, when a parameter is quenched from a gapped phase toward the quantum critical point. These unusual scaling laws originate from an anisotropic nature of the quantum critical point in the Kitaev model. Gerenalizing these results, we provide novel scaling laws for a generic anisotropic quantum critical point in d-dimensional systems.

Fast Dynamics of Protein Preservation in Sugar Glasses

Encapsulation in sugar-based glasses has long been employed to stabilize proteins against low temperatures and dehydration. However, the molecular origins of this effect have been unclear, and it fails to adequately preserve over one third of protein-based drugs. Recent experimental results have indicated that preservation time is strongly correlated with short-time dynamics of the glass. Accordingly, we employ molecular dynamics to investigate interrelations between several fast dynamic phenomena in glasses in order to elucidate the precise molecular origin of their preservative effect. Our results emphasize the presence of a post-inertial relaxation that exhibits unusual time scaling and that appears to be closely linked to the Debye-Waller factor, a caging size parameter that has been shown to strongly predict preservation quality. Longer-time relaxation of the glass, which is expected to intermediate between fast dynamics and long-time preservation effects, is shown to possess at least two relevant time scales: the first is a caging relaxation between distinct particles; and the second is a structural relaxation related to particle diffusion.

Numerical simulation of non-convex heat transfer of the weld pool surface during laser welding of titanium alloy

The coupled heat transfer and fluid flow behaviours during deep penetration laser welding of titanium alloy sheet were investigated with a coupled three-dimensional transient keyhole welding model and a high speed in situ CCD camera-based imaging system. An unusual small scale heat transfer phenomenon of the weld pool that the shape of some high temperature isothermal lines in the central part of top weld pool surface could be regularly concave towards to welding direction, was found by the theoretical modelling and high speed imaging experiments. It was shown that the occurrence of this phenomenon closely relates to the vigorously convective heat transfer of the weld pool.

Explosive Percolation Transition is Actually Continuous

Recently a discontinuous percolation transition was reported in a new "explosive percolation" problem for irreversible systems [D. Achlioptas, R. M. D'Souza, and J. Spencer, Science 323, 1453 (2009)] in striking contrast to ordinary percolation. We consider a representative model which shows that the explosive percolation transition is actually a continuous, second order phase transition though with a uniquely small critical exponent of the percolation cluster size. We describe the unusual scaling properties of this transition and find its critical exponents and dimensions.

Slow quench dynamics of the Kitaev model: Anisotropic critical point and effect of disorder

We study the non-equilibrium slow dynamics for the Kitaev model both in the presence and the absence of disorder. For the case without disorder, we demonstrate, via an exact solution, that the model provides an example of a system with an anisotropic critical point and exhibits unusual scaling of defect density $n$ and residual energy $Q$ for a slow linear quench. We provide a general expression for the scaling of $n$ ($Q$) generated during a slow power-law dynamics, characterized by a rate $\tau^{-1}$ and exponent $\alpha$, from a gapped phase to an anisotropic quantum critical point in $d$ dimensions, for which the energy gap $\Delta_{\vec k} \sim k_i^z$ for $m$ momentum components ($i=1..m$) and $\sim k_i^{z'}$ for the rest $d-m$ components ($i=m+1..d$) with $z\le z'$: $n \sim \tau^{-[m + (d-m)z/z']\nu \alpha/(z\nu \alpha +1)}$ ($Q \sim \tau^{-[(m+z)+ (d-m)z/z']\nu \alpha/(z\nu \alpha +1)}$). These general expressions reproduce both the corresponding results for the Kitaev model as a special case for $d=z'=2$ and $m=z=\nu=1$ and the well-known scaling laws of $n$ and $Q$ for isotropic critical points for $z=z'$. We also present an exact computation of all non-zero, independent, multispin correlation functions of the Kitaev model for such a quench and discuss their spatial dependence. For the disordered Kitaev model, where the disorder is introduced via random choice of the link variables $D_n$ in the model's Fermionic representation, we find that $n \sim \tau^{-1/2}$ and $Q\sim \tau^{-1}$ ($Q\sim \tau^{-1/2}$) for a slow linear quench ending in the gapless (gapped) phase. We provide a qualitative explanation of such scaling.

Tempo and scale of late Paleocene and early Eocene carbon isotope cycles: Implications for the origin of hyperthermals

The upper Paleocene and lower Eocene are marked by several prominent (> 1‰) carbon isotope (δ 13C) excursions (CIE) that coincide with transient global warmings, or thermal maxima, including the Paleocene–Eocene Thermal Maximum (PETM). The CIE, which are recorded mainly in marine sedimentary sequences, have also been identified in continental sequences, occurred episodically, and yet appear to be paced or triggered by orbital forcing. To constrain the timing and scale of the CIE relative to long-term baseline variability, we have constructed a 4.52 million year (myr) long, high-resolution (~ 3 kyr) bulk sediment carbon isotope record spanning the lower Eocene to upper Paleocene (C25r–C24n) from a pelagic sediment section recovered at ODP Site 1262 in the southeast Atlantic. This section, which was orbitally-tuned utilizing high-resolution core log physical property and geochemical records, is the most stratigraphically complete upper Paleocene to lower Eocene sequence recovered to date. Time-series analysis of the carbon isotope record along with a high-resolution Fe intensity record obtained by XRF core scanner reveal cyclicity with variance concentrated primarily in the precession (21 kyr) and eccentricity bands (100 and 400-kyr) throughout the upper Paleocene–lower Eocene. In general, minima in δ 13C correspond with peaks in Fe (i.e., carbonate dissolution), both of which appear to be in phase with maxima in eccentricity. This covariance is consistent with excess oceanic uptake of isotopically depleted carbon resulting in lower carbonate saturation during periods of high eccentricity. This relationship includes all late Paleocene and early Eocene CIE confirming pacing by orbital forcing. The lone exception is the PETM, which appears to be out of phase with the 400-kyr cycle, though possibly in phase with the 100-kyr cycle, reinforcing the notion that a mechanism other than orbital forcing and/or an additional source of carbon is required to account for the occurrence and unusual scale of this event.

Democracy Assistance as ἄτεχνον

(ProQuest: ... denotes Greek characters omitted (or Cyrillic characters omitted.))Westerners have been advising Arab leaders on how to organize themselves for a long time, and it has not always gone well. In the 1962 film by David Lean, Lawrence of Arabia, British assistance to the Arabs in their revolt against the Ottomans is dramatized. Arab leaders reject the advice of British army officers to build and train a modem, mechanized land force, and with the encouragement of TE. Lawrence, choose to adapt traditional Arab forms of warfare. The result is a series of Arab victories over the Turks. As allegory, this story brings us right up to the perpetual problem of the democracy assistance business: the inclination of benefactors to style themselves as dispensers of superior, technical expertise without sufficient deference to local practices and tradition. Lawrence's insight offers a more effective approach: jettisoning foreign models in favour of indigenous ones that can be understood and embraced by those we are attempting to assist.Although democracy assistance organizations are staffed by earnest young people with experience in the political systems of their home countries, few of them have Lawrence's affinity and knowledge of the history and traditions of the countries they hope to help. The gap between what is known by democracy assistance staff, and what by those they hope to help, can be wide and too often invisible to staff at foreign aid organizations. This is because foreign democracy assistance entails not only the transfer of technical information about good governance practices and international norms, but also another type of knowledge that only a local, or a rare outsider to a society, such as Lawrence, can understand. This elusive or protean knowledge can be described by the Greek adjective ?te????, or atechnon, which is most literally rendered as atechnical or nontechnical knowledge. If politics is sometimes considered a science, it nonetheless has a nontechnical side where the grasping, fumbling, practical art of politics takes over.Foreign democracy assistance is best able to address the technical side of governance, such as how to organize an election or how to use polling data to inform a campaign strategy, but when tasked with supporting indigenous institutions, democracy assistance must make use of the nontechnical as well. The challenge is to assist in the development of institutions by conveying knowledge in a manner that bridges the distance between internationaltechnical and local-nontechnical understandings.Given that the success of a representative democracy depends on an informed class of representatives as well as citizens, both groups ought to be the beneficiaries of international efforts. In practice, US and other foreign democracy assistance has tended to concentrate on public education through media and indigenous civil society advocacy organizations and on governmental education through technical training and on-the-ground advising. At the same time, valuable policy ideas can also emerge from domestic think tanks, whose scholars have an intellectual and cultural affinity for the society whose leaders they hope to advise, and who research the country's problems and recommend solutions in the language of local history and political idiom.As part of a larger effort to support the restoration of democratic self-government in Iraq, the International Republican Institute designed and conducted a training program to help develop independent, nongovernmental Iraqi policy research institutions - think tanks - from 2004 on. The initiative was part of a larger U S -government-funded effort to promote the development of civil society and democratic institutions in Iraq. The unusual scale of funding for Iraq made this experimental effort possible.The institute was not responsible for the creation of think tanks in Iraq. The country had the benefit of a group of scholars at home and abroad with knowledge of political science, democratic institutions, law, and public policy. …

Re-examining the directional-ordering transition in the compass model with screw-periodic boundary conditions

We study the directional-ordering transition in the two-dimensional classical and quantum compass models on the square lattice by means of Monte Carlo simulations. An improved algorithm is presented which builds on the Wolff cluster algorithm in one-dimensional subspaces of the configuration space. This improvement allows us to study classical systems up to L=512. Based on this algorithm, we give evidence for the presence of strongly anomalous scaling for periodic boundary conditions which is much worse than anticipated before. We propose and study alternative boundary conditions for the compass model which do not make use of extended configuration spaces and show that they completely remove the problem with finite-size scaling. In the last part, we apply these boundary conditions to the quantum problem and present a considerably improved estimate for the critical temperature which should be of interest for future studies on the compass model. Our investigation identifies a strong one-dimensional magnetic ordering tendency with a large correlation length as the cause of the unusual scaling and moreover allows for a precise quantification of the anomalous length scale involved.