Inversion of the Diffraction Pattern from an Inhomogeneously Strained Crystal using an Iterative Algorithm

The displacement field in highly non uniformly strained crystals is obtained by addition of constraints to an iterative phase retrieval algorithm. These constraints include direct space density uniformity and also constraints to the sign and derivatives of the different components of the displacement field. This algorithm is applied to an experimental reciprocal space map measured using high resolution X-ray diffraction from an array of silicon lines and the obtained component of the displacement field is in very good agreement with the one calculated using a finite element model.Comment: 5 pages, 4 figure

Finite to infinite steady state solutions, bifurcations of an integro-differential equation

We consider a bistable integral equation which governs the stationary solutions of a convolution model of solid--solid phase transitions on a circle. We study the bifurcations of the set of the stationary solutions as the diffusion coefficient is varied to examine the transition from an infinite number of steady states to three for the continuum limit of the semi--discretised system. We show how the symmetry of the problem is responsible for the generation and stabilisation of equilibria and comment on the puzzling connection between continuity and stability that exists in this problem

Instabilities and disorder of the domain patterns in the systems with competing interactions

The dynamics of the domains is studied in a two-dimensional model of the microphase separation of diblock copolymers in the vicinity of the transition. A criterion for the validity of the mean field theory is derived. It is shown that at certain temperatures the ordered hexagonal pattern becomes unstable with respect to the two types of instabilities: the radially-nonsymmetric distortions of the domains and the repumping of the order parameter between the neighbors. Both these instabilities may lead to the transformation of the regular hexagonal pattern into a disordered pattern.Comment: ReVTeX, 4 pages, 3 figures (postscript); submitted to Phys. Rev. Let

Hygroscopic properties of different aerosol types over the Atlantic and Indian Oceans

Hygroscopic properties of atmospheric particles were studied in the marine tropospheric boundary layer over the Atlantic and Indian Oceans during two consecutive field studies: the Aerosols99 cruise (Atlantic Ocean) from 15 January to 20 February 1999, and the INDOEX cruise (Indian Ocean Experiment) from 23 February to 30 March 1999. The hygroscopic properties were compared to optical and chemical properties, such as absorption, chemical inorganic composition, and mass concentration of organic and elemental carbon, to identify the influence of these parameters on hygroscopicity. During the two field studies, four types of aerosol-sampling instruments were used on board the NOAA (National Oceanic and Atmospheric Administration) Research Vessel Ronald H. Brown: Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA), seven-stage cascade impactor, two-stage cascade impactor, and Particle Soot Absorption Photometer (PSAP). The HTDMA was used to determine the hygroscopic properties of atmospheric particles at initial dry sizes (Dp) of 50, 150, and 250 nm and at relative humidities (RH) of 30, 55, 75, and 90%. Simultaneously, a seven-stage cascade impactor of which 3 stages were in the sub-mm size range was used to determine the molar composition of the major inorganic ions such as ammonium and sulfate ions. A two-stage cascade impactor (1 in the sub-mm size range, 1 in the sup-mm size range) was used to determine the mass concentration of organic and elemental carbon. The PSAP was used (at a wavelength of 565 nm) to measure the light absorption coefficient of the aerosol. During the two field studies, air masses of several different origins passed the ship's cruise path. The occurrence of different air masses was classified into special time periods signifying the origin of the observed aerosol. All time periods showed a group of particles with high hygroscopic growth. The measured average hygroscopic growth factors defined by the ratio of dry and wet particle diameter at 90% RH ranged from 1.6 to 2.0, depending on the dry particle size and on the type of air mass. Particles with low hygroscopic growth occurred only when continentally influenced air masses arrived at the ship's position. Distinctions in hygroscopic growth of particles of different air masses were more significant for small relative humidities (30% or 55% RH). High concentrations of elemental carbon corresponded with high light absorption coefficients and with the occurrence of less-hygroscopic and nearly hydrophobic particle fractions in the hygroscopic growth distributions. A key finding is that clean marine air masses that had no land contact for five to six days could clearly be distinguished from polluted air masses that had passed over a continent several days before reaching the ship

Movement Variability Increases With Shoulder Pain When Compensatory Strategies of the Upper Body Are Constrained

[DE] This cross-sectional study analyzed the influence of chronic shoulder pain (CSP) on movement variability/kinematics during humeral elevation, with the trunk and elbow motions constrained to avoid compensatory strategies. For this purpose, 37 volunteers with CSP as the injured group (IG) and 58 participants with asymptomatic shoulders as the control group (CG) participated in the study. Maximum humeral elevation (Emax), maximum angular velocity (Velmax), variability of the maximum angle (CVEmax), functional variability (Func_var), and approximate entropy (ApEn) were calculated from the kinematic data. Patients' pain was measured on the visual analogue scale (VAS). Compared with the CG, the IG presented lower Emax and Velmax and higher variability (i.e., CVEmax, Func_var, and ApEn). Moderate correlations were achieved for the VAS score and the kinematic variables Emax, Velmax and variability of curve analysis, Func_varm, and ApEn. No significant correlation was found for CVEmax. In conclusion, CSP results in a decrease of angle and velocity and an increased shoulder movement variability when the neuromuscular system cannot use compensatory strategies to avoid painful positions.This work was funded by the Spanish Government and cofinanced by EU FEDER funds (Grant DPI2013-44227-R)Lopez Pascual, J.; Page Del Pozo, AF.; Serra Añó, P. (2017). Movement Variability Increases With Shoulder Pain When Compensatory Strategies of the Upper Body Are Constrained. Journal of Motor Behavior. 1-8. https://doi.org/10.1080/00222895.2017.1371109S1

ICT for Sustainable Last-Mile Logistics: Data, People and Parcels

In this paper we present a vision of how ICT can be leveraged to help combat the impact on pollution, congestion and carbon emissions contributed by the parcel delivery sector. This is timely given annual growth in parcel deliveries, especially same-day deliveries, and the need to inform initiatives to clean up our cities such as the sales ban on new petrol and diesel vehicles in the UK by 2040. Our insights are informed by research on parcel logistics in Central London, leveraging a data set of parcel manifests spanning 6 months. To understand the impact of growing e-commerce trends on parcel deliveries we provide a mixed methods case study leveraging data-driven analysis and qualitative fieldwork to demonstrate how ICT can uncover the impact of parcel deliveries on delivery drivers and their delivery rounds during seasonal deliveries (or “the silly season”). We finish by discussing key opportunities for intervention and further research in ICT4S and co-created Smart Cities, connecting our findings with existing research and data as a call to the ICT4S community to help tackle the growth in carbon emissions, pollution and congestion linked to parcel deliveries

Ambitious partnership needed for reliable climate prediction.

Current global climate models struggle to represent precipitation and related extreme events, with serious implications for the physical evidence base to support climate actions. A leap to kilometre-scale models could overcome this shortcoming but requires collaboration on an unprecedented scale

Western Juniper Field Guide: Asking the Right Questions to Select Appropriate Management Actions

Strong evidence indicates that western juniper has significantly expanded its range since the late 1800s by encroaching into landscapes once dominated by shrubs and herbaceous vegetation (fig. 1). Woodland expansion affects soil resources, plant community structure and composition, water, nutrient and fire cycles, forage production, wildlife habitat, and biodiversity. Goals of juniper management include an attempt to restore ecosystem function and a more balanced plant community that includes shrubs, grasses, and forbs, and to increase ecosystem resilience to disturbances. Developing a management strategy can be a difficult task due to uncertainty about how vegetation, soils, hydrologic function, and wildlife will respond to treatments. When developing a management strategy, the first and possibly most important step towards success is asking the right questions. Identifying the attributes of the area to be treated and selecting the right treatments to be applied are of utmost importance. One must ask questions addressing the kind of site (that is, potential natural vegetation, soils, etc.), the current state of the site (that is, successional, hydrologic, etc.), what components need to be restored, how the management unit fits in with the overall landscape mosaic, and the long-term goals and objectives for the area or region. Keep in mind sagebrush-steppe vegetation is dynamic and management strategies must take into account multi-decade time frames. This guide provides a set of tools that will help field biologists, land managers, and private landowners conduct rapid qualitative field assessments that address the kind of site and its current state. These tools include a list of questions to be addressed and a series of photographs, keys, tables, and figures to help evaluate a site. Conducting this assessment will help prioritize sites to be treated, select the best treatment, and predict outcomes. Success of a juniper management program may be greatly enhanced if an interdisciplinary team of local managers and resource specialists, who are experienced with vegetation, fuels, soils, hydrology, wildlife, and economic and sociological aspects of the local resource, use this guide to aid their decision-making