Evidence for spin liquid ground state in SrDy2_2O4_4 frustrated magnet probed by muSR

Muon spin relaxation ($\mu$SR) measurements were carried out on SrDy$_2$O$_4$, a frustrated magnet featuring short range magnetic correlations at low temperatures. Zero-field muon spin depolarization measurements demonstrate that fast magnetic fluctuations are present from $T=300$ K down to 20 mK. The coexistence of short range magnetic correlations and fluctuations at $T=20$ mK indicates that SrDy$_2$O$_4$ features a spin liquid ground state. Large longitudinal fields affect weakly the muon spin depolarization, also suggesting the presence of fast fluctuations. For a longitudinal field of $\mu_0H=2$ T, a non-relaxing asymmetry contribution appears below $T=6$ K, indicating considerable slowing down of the magnetic fluctuations as field-induced magnetically-ordered phases are approached.Comment: 6 pages, 4 figures, to be published as a proceeding of HFM2016 in Journal of Physics: Conference Series (JPCS

The LIM-Homeodomain Protein Islet Dictates Motor Neuron Electrical Properties by Regulating K+ Channel Expression

Neuron electrical properties are critical to function and generally subtype specific, as are patterns of axonal and dendritic projections. Specification of motoneuron morphology and axon pathfinding has been studied extensively, implicating the combinatorial action of Lim-homeodomain transcription factors. However, the specification of electrical properties is not understood. Here, we address the key issues of whether the same transcription factors that specify morphology also determine subtype specific electrical properties. We show that Drosophila motoneuron subtypes express different K(+) currents and that these are regulated by the conserved Lim-homeodomain transcription factor Islet. Specifically, Islet is sufficient to repress a Shaker-mediated A-type K(+) current, most likely due to a direct transcriptional effect. A reduction in Shaker increases the frequency of action potential firing. Our results demonstrate the deterministic role of Islet on the excitability patterns characteristic of motoneuron subtypes

Nonlinear dynamics of large amplitude dust acoustic shocks and solitary pulses in dusty plasmas

We present a fully nonlinear theory for dust acoustic (DA) shocks and DA solitary pulses in a strongly coupled dusty plasma, which have been recently observed experimentally by Heinrich et al. [Phys. Rev. Lett. 103, 115002 (2009)], Teng et al. [Phys. Rev. Lett. 103, 245005 (2009)], and Bandyopadhyay et al. [Phys. Rev. Lett. 101, 065006 (2008)]. For this purpose, we use a generalized hydrodynamic model for the strongly coupled dust grains, accounting for arbitrary large amplitude dust number density compressions and potential distributions associated with fully nonlinear nonstationary DA waves. Time-dependent numerical solutions of our nonlinear model compare favorably well with the recent experimental works (mentioned above) that have reported the formation of large amplitude non-stationary DA shocks and DA solitary pulses in low-temperature dusty plasma discharges.Comment: 9 pages, 4 figures. To be published in Physical Review

Motivations for servitization: The impact of product complexity

Purpose – The purpose of this paper is to identify the commonalities and differences in manufacturers’ motivations to servitise. Design/methodology/approach – UK study based on interviews with 40 managers in 25 companies in 12 sectors. Using the concept of product complexity, sectors were grouped using the Complex Products and systems (CoPS) typology: non-complex products, complex products and systems. Findings – Motivations to servitise were categorised as competitive, demand based (i.e. derived from the customer) or economic. Motivations to servitise vary according to product complexity, although cost savings and improved service quality appear important demand-based motivations for all manufacturers. Non-complex product manufacturers also focus on services to help product differentiation. For CoPS manufacturers, both risk reduction and developing a new revenue stream were important motivations. For uniquely complex product manufacturers, stabilising revenue and increased profitability were strong motivations. For uniquely systems manufacturers, customers sought business transformation, whilst new service business models were also identified. Research limitations/implications – Using the CoPS typology, this study delineates motivations to servitise by sector. The findings show varying motivations to servitise as product complexity increases, although some motivational commonality existed across all groups. Manufacturers may have products of differing complexity within their portfolio. To overcome this limitation the unit of analysis was the strategic business unit. Practical implications – Managers can reflect on and benchmark their motivation for, and opportunities from, servitisation, by considering product complexity. Originality/value – The first study to categorise servitisation motivations by product complexity. Identifying that some customers of systems manufacturers seek business transformation through outsourcing

Quantum spin chain as a potential realization of the Nersesyan-Tsvelik model

It is well established that long-range magnetic order is suppressed in magnetic systems whose interactions are low-dimensional. The prototypical example is the S-1/2 Heisenberg antiferromagnetic chain (S-1/2 HAFC) whose ground state is quantum critical. In real S-1/2 HAFC compounds interchain coupling induces long-range magnetic order although with a suppressed ordered moment and reduced N\'eel temperature compared to the Curie-Weiss temperature. Recently, it was suggested that order can also be suppressed if the interchain interactions are frustrated, as for the Nersesyan-Tsvelik model. Here, we study the new S-1/2 HAFC, (NO)[Cu(NO3)3]. This material shows extreme suppression of order which furthermore is incommensurate revealing the presence of frustration consistent with the Nersesyan-Tsvelik model

Superfast non-linear diffusion: capillary transport in particulate porous media

The migration of liquids in porous media, such as sand, has been commonly considered at high saturation levels with liquid pathways at pore dimensions. In this letter we reveal a low saturation regime observed in our experiments with droplets of extremely low volatility liquids deposited on sand. In this regime the liquid is mostly found within the grain surface roughness and in the capillary bridges formed at the contacts between the grains. The bridges act as variable-volume reservoirs and the flow is driven by the capillary pressure arising at the wetting front according to the roughness length scales. We propose that this migration (spreading) is the result of interplay between the bridge volume adjustment to this pressure distribution and viscous losses of a creeping flow within the roughness. The net macroscopic result is a special case of non-linear diffusion described by a superfast diffusion equation (SFDE) for saturation with distinctive mathematical character. We obtain solutions to a moving boundary problem defined by SFDE that robustly convey a time power law of spreading as seen in our experiments

Developing your own graduate employees: Employer perspectives on the value of a degree apprenticeship

The purpose of this paper is to offer an employer perspective on the value of degree apprenticeships (DAs) less than a year after the first apprentices commenced their studies for a bachelor's degree in September 2015. Design/methodology/approach - This case focusses on one of the first DAs in the UK. It draws on evidence from interviews with HR professionals responsible for the DA in two contrasting companies, an international PLC and a smaller, fast growing enterprise. Findings - Both employers consider that the DA meets recruitment needs in ways that other options do not. They particularly value the ability of apprentices to make an immediate contribution in the workplace. For the smaller employer the university support structures are a significant advantage. Only the larger employer formally input into the curriculum prior to validation but both feel they can tailor content to suit their needs. Both see investing in the DA as excellent value for money. Practical implications - The value of strong relationships, trust and ongoing dialogue between partners emerges as a key component in fulfilling the need of employers. Originality/value - The DA model recasts employers as the purchasers of higher education and affords them a key role in developing provision tailored to their needs. Implications of this new model for employers, universities and learners are potentially profound and hard to predict. This case study is based on part of the early stage of a three-year research programme. It provides a unique, early insight into two employers' rationales for engaging with the DA programme and their initial experiences