Zigzag transitions and nonequilibrium pattern formation in colloidal chains

Paramagnetic colloidal particles that are optically trapped in a linear array can form a zigzag pattern when an external magnetic field induces repulsive interparticle interactions. When the traps are abruptly turned off, the particles form a nonequilibrium expanding pattern with a zigzag symmetry, even when the strength of the magnetic interaction is weaker than that required to break the linear symmetry of the equilibrium state. We show that the transition to the equilibrium zigzag state is always potentially possible for purely harmonic traps. For anharmonic traps that have a finite height, the equilibrium zigzag state becomes unstable above a critical anharmonicity. A normal mode analysis of the equilibrium line configuration demonstrates that increasing the magnetic field leads to a hardening and softening of the spring constants in the longitudinal and transverse directions, respectively. The mode that first becomes unstable is the mode with the zigzag symmetry, which explains the symmetry of nonequilibrium patterns. Our analytically tractable models help to give further insight into the way that the interplay of such factors as the length of the chain, hydrodynamic interactions, thermal fluctuations affect the formation and evolution of the experimentally observed nonequilibrium patterns.Comment: 16 pages, 8 figures; to appear in the Journal of Chemical Physic

Coastal permafrost landscape development since the Late Pleistocene in the western Laptev Sea, Siberia

The palaeoenvironmental development of the western Laptev Sea is understood primarily from investigations of exposed cliffs and surface sediment cores from the shelf. In 2005, a core transect was drilled between the Taymyr Peninsula and the Lena Delta, an area that was part of the westernmost region of the non-glaciated Beringian landmass during the late Quaternary. The transect of five cores, one terrestrial and four marine, taken near Cape Mamontov Klyk reached 12km offshore and 77m below sea level. A multiproxy approach combined cryolithological, sedimentological, geochronological (C-14-AMS, OSL on quartz, IR-OSL on feldspars) and palaeoecological (pollen, diatoms) methods. Our interpretation of the proxies focuses on landscape history and the transition of terrestrial into subsea permafrost. Marine interglacial deposits overlain by relict terrestrial permafrost within the same offshore core were encountered in the western Laptev Sea. Moreover, the marine interglacial deposits lay unexpectedly deep at 64m below modern sea level 12km from the current coastline, while no marine deposits were encountered onshore. This implies that the position of the Eemian coastline presumably was similar to today's. The landscape reconstruction suggests Eemian coastal lagoons and thermokarst lakes, followed by Early to Middle Weichselian fluvially dominated terrestrial deposition. During the Late Weichselian, this fluvial landscape was transformed into a poorly drained accumulation plain, characterized by widespread and broad ice-wedge polygons. Finally, the shelf plain was flooded by the sea during the Holocene, resulting in the inundation and degradation of terrestrial permafrost and its transformation into subsea permafrost

The Einstein relation generalized to non-equilibrium

The Einstein relation connecting the diffusion constant and the mobility is violated beyond the linear response regime. For a colloidal particle driven along a periodic potential imposed by laser traps, we test the recent theoretical generalization of the Einstein relation to the non-equilibrium regime which involves an integral over measurable velocity correlation functions

Is Heavy Baryon Approach Necessary?

It is demonstrated that using an appropriately chosen renormalization condition one can respect power counting within the relativistic baryon chiral perturbation theory without appealing to the technique of the heavy baryon approach. Explicit calculations are performed for diagrams including two-loops. It is argued that the introduction of the heavy baryon chiral perturbation theory was useful but not necessary.Comment: 9 pages, 2 figures, minor changes, references adde

NPTI: New Periodic Emission Inspection to guarantee PN Emission Stability of all modern vehicles

Periodic Technical Inspection of emission quality PTI was abandoned by most EU member states in 2014 following the EU-Directive 2014/45 which recommended to delegate emission quality to OBD. After Dieselgate this naïve dream was over and VERT proposed during the German Dieselgate Hearing Sept.2016 to re-introduce PTI for all vehicles with emission control by DPF and SCR. With the introduction of particulate filters on diesel as well as GDI engines, the measurement of particulate emissions during PTI or road-side checks however, became a nontrivial task. Opacity and smoke meters do not have sufficient sensitivity to identify particulate filter failures or tampering on new, low emission internal combustion engines. Recent studies conducted in the Netherlands, Switzerland and Belgium have shown that about 10% of passenger cars equipped with DPF have high PN emissions that could indicate a damaged or removed DPF. To address this problem, the VERT Association launched a New Periodic Technical Inspection (N-PTI) initiative to develop a simple, robust and tamper-proof method for checking the functionality of DPFs using particle number (PN) instruments. The N-PTI initiative, launched in November 2016, is supported by the European Union as well as the governments of Germany, the Netherlands, Belgium, and Switzerland. The proposed test is conducted at idle using a PN instrument. It is assumed that the process will be suitable with minor, if any, modifications for petrol engines. The test protocol is also appropriate for road-side inspections, such as by the police. The first results are promising. Instruments in their prototype stage are already capable of recognizing vehicles that have been manipulated using partial bypass that resulted in PN emissions close to maximum allowed type approval levels (i.e., 6×1011 1/km) and present a satisfactory correlation with PEMS compliant instrumentation. Work on the testing procedure and pass/fail limit is still ongoing. This work is also under the evaluation of the CITA (International Motor Vehicle Inspection Committee) Roadworthiness Technical Working Group which focuses on tampering with exhaust emission control systems. The results show a good correlation between emission levels during the type approval cycle (NEDC/ WLTC) and low idle emissions even with first generation N-PTI instruments. These results suggest that the technical specifications of NPTI instruments should have acceptable uncertainty, with low cost. The Netherlands and Germany have already started programs that will lead to the adoption of mandatory N-PTI emission testing requirements. NMI, the Dutch metrology institute, has released a draft InternationalRecommendation with the specifications of the PTI particulate number counter. The N-PTI DPF test maybecome available in the Netherlands at RDW test stations as soon as 2019, while the nationwide targetdate for the introduction of N-PTI testing is 2021. In Germany, the Federal Council passed a law inSeptember 2017 (published in the German StVZO 2017) that re-introduces PTI first by smokemeasurement but PN measurements at idle are to be required from 2021

Projection of Populations by Level of Educational Attainment, Age and Sex for 120 Countries for 2005-2050

Using demographic multi-state methods, this paper presents projections for the population of 120 countries (covering 93 percent of the world population in 2000) by age, sex and level of educational attainment for the years 2000 to 2050. The dataset produced gives the full educational attainment distributions for four categories (no education, primary, secondary and tertiary education) by five-year age groups, with definitions that are consistent with a previous reconstruction of educational attainment for the years 1970 to 2000. Based on empirical distributions of educational attainment by age and sex for the year 2000, the method moves along cohort lines while taking into account differentials in fertility and mortality by education level. The most extensive in time and geographical coverage to date, to our knowledge this work represents the first attempt to project future educational attainment trends based on a statistical model of historical international attainment growth. The resulting dataset provides valuable insights both on the feasibility of international education targets and on their implications for human capital and population size and age structure

Fractional transport equations for Levy stable processes

The influence functional method of Feynman and Vernon is used to obtain a quantum master equation for a Brownian system subjected to a Levy stable random force. The corresponding classical transport equations for the Wigner function are then derived, both in the limit of weak and strong friction. These are fractional extensions of the Klein-Kramers and the Smoluchowski equations. It is shown that the fractional character acquired by the position in the Smoluchowski equation follows from the fractional character of the momentum in the Klein-Kramers equation. Connections among fractional transport equations recently proposed are clarified.Comment: 4 page