Continuous and discrete Clebsch variational principles

The Clebsch method provides a unifying approach for deriving variational principles for continuous and discrete dynamical systems where elements of a vector space are used to control dynamics on the cotangent bundle of a Lie group \emph{via} a velocity map. This paper proves a reduction theorem which states that the canonical variables on the Lie group can be eliminated, if and only if the velocity map is a Lie algebra action, thereby producing the Euler-Poincar\'e (EP) equation for the vector space variables. In this case, the map from the canonical variables on the Lie group to the vector space is the standard momentum map defined using the diamond operator. We apply the Clebsch method in examples of the rotating rigid body and the incompressible Euler equations. Along the way, we explain how singular solutions of the EP equation for the diffeomorphism group (EPDiff) arise as momentum maps in the Clebsch approach. In the case of finite dimensional Lie groups, the Clebsch variational principle is discretised to produce a variational integrator for the dynamical system. We obtain a discrete map from which the variables on the cotangent bundle of a Lie group may be eliminated to produce a discrete EP equation for elements of the vector space. We give an integrator for the rotating rigid body as an example. We also briefly discuss how to discretise infinite-dimensional Clebsch systems, so as to produce conservative numerical methods for fluid dynamics

E-recruitment: Towards an ubiquitous recruitment process and candidate relationship management

Up to now, there has been little research on the impact of e-recruitment on the recruitment process as a whole. The present study fills part of this gap by investigating the effect of e-recruitment on the design of the recruitment process. Three explorative case studies were carried out in three large organisations in Denmark in 2008-2010. The findings indicate that e-recruitment transforms the traditional recruitment process into a time- and space-independent, collaborative hiring process. The most significant changes are recorded in the sequence and increased divisibility of main recruitment tasks and subtasks. For management, the main task is now that of communicating with candidates. In addition, a new on-going task of maintaining a corporate career website has become an integral part of the new recruitment process. The new design is presented in the following, and its implications briefly discussed.Bis heute wurden die Auswirkungen von E-Recruiting auf den gesamten Rekrutierungsprozess wenig erforscht. Die vorliegende Studie zielt darauf ab, diese Forschungslücke durch die Untersuchung der Auswirkung von E-Recruiting auf die Gestaltung des Rekrutierungsprozesses teilweise zu schließen. Der Beitrag basiert dabei auf drei explorativen Fallstudien in drei großen dänischen Organisationen in den Jahren 2008-2010. Die Ergebnisse lassen darauf schließen, dass E-Recruiting den traditionellen Rekrutierungsprozess in einen zeit- und raumunabhängigen, kollaborativen Prozess transformiert. Dies stellt sich insbesondere in der Modifikation der Aufgabenabfolge und der erhöhten Teilbarkeit der Rekrutierungsaufgaben heraus. Zudem ist hervorzuheben, dass sich die Kommunikation mit den Bewerbern als eine zentrale neue Managementaufgabe herausbildet. Darüber hinaus bildet die permanente Pflege der Karriere-Website einen integralen Teil des neuen Rekrutierungsprozesses. Damit stellt dieser Beitrag generell die technologische Neugestaltung von Rekrutierungsprozessen vor und diskutiert deren Auswirkungen

Finite Size Polyelectrolyte Bundles at Thermodynamic Equilibrium

We present the results of extensive computer simulations performed on solutions of monodisperse charged rod-like polyelectrolytes in the presence of trivalent counterions. To overcome energy barriers we used a combination of parallel tempering and hybrid Monte Carlo techniques. Our results show that for small values of the electrostatic interaction the solution mostly consists of dispersed single rods. The potential of mean force between the polyelectrolyte monomers yields an attractive interaction at short distances. For a range of larger values of the Bjerrum length, we find finite size polyelectrolyte bundles at thermodynamic equilibrium. Further increase of the Bjerrum length eventually leads to phase separation and precipitation. We discuss the origin of the observed thermodynamic stability of the finite size aggregates

An integrable shallow water equation with peaked solitons

We derive a new completely integrable dispersive shallow water equation that is biHamiltonian and thus possesses an infinite number of conservation laws in involution. The equation is obtained by using an asymptotic expansion directly in the Hamiltonian for Euler's equations in the shallow water regime. The soliton solution for this equation has a limiting form that has a discontinuity in the first derivative at its peak.Comment: LaTeX file. Figure available from authors upon reques

Corrección del ángulo intermetatarsiano del Hallux Valgus mediante anclajes de endo-botones de alambre

The 1st-2nd intermetatarsal angular component of the hallux valgus deformity can be corrected by an osteotomysparing technique using ultra high molecular weight polyethylene (UHMWPE) braided suture (Fiberwire, Arthrex, Naples, FL) attached endo-buttons to reduce and maintain the correction. This paper will outline the surgical approach, advantages and post-operative care necessary to implement this technique.El componente angular del primer y Segundo espacio intermetarsal puede ser corregido mediante una técnica de osteotomía de preservación utilizando un hilo de sutura trenzado de polietileno de alto peso molecular (Fiberwire, Arthrex, Naples, FL), insertando endo botones para reducir y mantener la corrección. En este documento se describe el abordaje quirúrgico, las ventajas y los cuidados postoperatorios necesarios para aplicar esta técnica

Electrophoresis of colloidal dispersions in the low-salt regime

We study the electrophoretic mobility of spherical charged colloids in a low-salt suspension as a function of the colloidal concentration. Using an effective particle charge and a reduced screening parameter, we map the data for systems with different particle charges and sizes, including numerical simulation data with full electrostatics and hydrodynamics and experimental data for latex dispersions, on a single master curve. We observe two different volume fraction-dependent regimes for the electrophoretic mobility that can be explained in terms of the static properties of the ionic double layer.Comment: Substantially revised versio

Signalment risk factors for cutaneous and renal glomerular vasculopathy (Alabama rot) in dogs in the UK

Seasonal outbreaks of cutaneous and renal glomerular vasculopathy (CRGV) have been reported annually in UK dogs since 2012, yet the aetiology of the disease remains unknown. The objectives of this study were to explore whether any breeds had an increased or decreased risk of being diagnosed with CRGV, and to report on age and sex distributions of CRGV cases occurring in the UK. Multivariable logistic regression was used to compare 101 dogs diagnosed with CRGV between November 2012 and May 2017 with a denominator population of 446,453 dogs from the VetCompass database. Two Kennel Club breed groups—hounds (odds ratio (OR) 10.68) and gun dogs (OR 9.69)—had the highest risk of being diagnosed with CRGV compared with terriers, while toy dogs were absent from among CRGV cases. Females were more likely to be diagnosed with CRGV (OR 1.51) as were neutered dogs (OR 3.36). As well as helping veterinarians develop an index of suspicion for the disease, better understanding of the signalment risk factors may assist in the development of causal models for CRGV and help identify the aetiology of the disease

Digital Creativity Support for Original Journalism

The decline in circulations and revenues resulting from the digitalization of news production and consumption has led to a crisis in journalism.Journalists have less time to research, investigate and write original stories, leading to problems for our democratic processes and holding the powerful to account. This paper reports the architecture, features and rationale for new digital creativity support designed to support journalists to discover more original angles onstories. It also summarises the evaluation of the tool’s use in 3 newsrooms