3,575 research outputs found
A new Rothamsted long-term field experiment for the twenty-first century - principles and practice
Agriculture faces potentially competing societal demands to produce food, fiber and fuel while reducing negative environmental impacts and delivering regulating, supporting and cultural ecosystem services. This necessitates a new generation of long-term agricultural field experiments designed to study the behavior of contrasting cropping systems in terms of multiple outcomes. We document the principles and practices of a new long-term experiment of this type at Rothamsted, established at two contrasting sites in 2017 and 2018, and report initial yield data at the crop and system level. The objective of the Large-Scale Rotation Experiment was to establish gradients of system properties and outcomes to improve our fundamental understanding of UK cropping systems. It is composed of four management factorsâphased rotations, cultivation (conventional vs reduced tillage), nutrition (additional organic amendment vs standard mineral fertilization) and crop protection (conventional vs smart crop protection). These factors were combined in a balanced design resulting in 24 emergent cropping systems at each site and can be analyzed at the level of the system or component management factors. We observed interactions between management factors and with the environment on crop yields, justifying the systems level, multi-site approach. Reduced tillage resulted in lower wheat yields but the effect varied with rotation, previous-crop and site. Organic amendments significantly increased spring barley yield by 8% on average though the effect again varied with site. The plowed cropping systems tended to produce higher caloric yield overall than systems under reduced tillage. Additional response variables are being monitored to study synergies and trade-offs with outcomes other than yield at the cropping system level. The experiment has been established as a long-term resource for inter-disciplinary research. By documenting the design process, we aim to facilitate the adoption of similar approaches to system-scale agricultural experimentation to inform the transition to more sustainable cropping systems
Shot noise of large charge quanta in superconductor/semiconductor/superconductor junctions
We have found experimentally that the noise of ballistic electron transport
in a superconductor/semiconductor/superconductor junction is enhanced relative
to the value given by the general relation, S_V=2eIR^2coth(eV/2kT), for two
voltage regions in which this expression reduces to its thermal and shot noise
limits. The noise enhancement is explained by the presence of large charge
quanta, with effective charge q*=(1+2Delta/eV)e, that generate a noise spectrum
S_V=2q*IR^2, as predicted in Phys. Rev. Lett. 76, 3814 (1996). These charge
quanta result from multiple Andreev reflections at each junction interface,
which are also responsible for the subharmonic gap structure observed in the
voltage dependence of the junction's conductance.Comment: 5 pages, 5 figures, submitted to Physical Review B as a Rapid
Communication. v2 author name in reference corrected. v3 added references. v4
clarifications in the text and reference added thanks to C. Urbin
"From âWhat the hell is going on?â to the âMushy middle groundâ to âgetting used to a new normalâ: Young peopleâs biographical narratives around navigating parental dementia"
The number of young people who have a parent with dementia is rising as a result of improvements in diagnosis of young onset variants and demographic shifts. There has, however, been very little research focusing on this group. Accounts elicited as part of the Perceptions and Experiences of Young People With a Parent With Dementia described the period, usually some years, leading up to a diagnosis of a dementia and then the progress of the condition post diagnosis. These narratives were characterised by confusion, uncertainty, trauma and distress as the young people struggled to make sense of the significant and often extreme, behavioural and attitudinal changes that were symptoms of the illness. This paper describes and discusses how the young people experienced and navigated the temporal messiness and consequent biographical disruption arising from parental dementia
Electrodynamics of balanced charges
In this work we modify the wave-corpuscle mechanics for elementary charges
introduced by us recently. This modification is designed to better describe
electromagnetic (EM) phenomena at atomic scales. It includes a modification of
the concept of the classical EM field and a new model for the elementary charge
which we call a balanced charge (b-charge). A b-charge does not interact with
itself electromagnetically, and every b-charge possesses its own elementary EM
field. The EM energy is naturally partitioned as the interaction energy between
pairs of different b-charges. We construct EM theory of b-charges (BEM) based
on a relativistic Lagrangian with the following properties: (i) b-charges
interact only through their elementary EM potentials and fields; (ii) the field
equations for the elementary EM fields are exactly the Maxwell equations with
proper currents; (iii) a free charge moves uniformly preserving up to the
Lorentz contraction its shape; (iv) the Newton equations with the Lorentz
forces hold approximately when charges are well separated and move with
non-relativistic velocities. The BEM theory can be characterized as
neoclassical one which covers the macroscopic as well as the atomic spatial
scales, it describes EM phenomena at atomic scale differently than the
classical EM theory. It yields in macroscopic regimes the Newton equations with
Lorentz forces for centers of well separated charges moving with
nonrelativistic velocities. Applied to atomic scales it yields a hydrogen atom
model with a frequency spectrum matching the same for the Schrodinger model
with any desired accuracy.Comment: Manuscript was edited to improve the exposition and to remove noticed
typo
during the 2009 Prime Expedition Scientific Cruise (PESC-09)
www.atmos-chem-phys.net/14/8137/2014/ doi:10.5194/acp-14-8137-201
Application of Renormalization to Potential Scattering
A recently proposed renormalization scheme can be used to deal with
nonrelativistic potential scattering exhibiting ultraviolet divergence in
momentum space. A numerical application of this scheme is made in the case of
potential scattering with divergence for small r, common in molecular
and nuclear physics, by the use of cut-offs in momentum and configuration
spaces. The cut-off is finally removed in terms of a physical observable and
model-independent result is obtained at low energies. The expected variation of
the off-shell behavior of the t matrix arising from the renormalization scheme
is also discussed.Comment: 15 pages plus 5 figure
Future proofing a long-term agricultural experiment for decades to come : Relocation and redesign
We are extremely grateful to generations of staff at SRUC and its predecessor organisations (NOSCA and SAC) for maintaining the Woodlands Field experiments at Craibstone over 100 years and to I&N Campbell who carefully prepared the new site and moved the soils in July 2021. The move of the soils was funded by SRUC. The molecular analysis of the soils from the pH experiment was conducted within the Soil Biology and Soil Health (SBSH) Partnership, funded by the Agriculture and Horticulture Development Board (AHDB) and the British Beet Research Organisation (BBRO) in the United Kingdom. We also gratefully acknowledge many colleagues from research and consultancy organisations in the UK and Europe who contributed to discussions during the redesign process. Professor Tony Edwards and Dr John Baddeley were both integral to the decision to move and redesign the pH Experiment. We are grateful to Allan Lilly, James Hutton Institute for allowing us to archive soils from both Woodlands Field experiments in the National Soils Archive. Thank you to Rosie Boyko and Nicola Holden (SRUC) and John Elphinstone (FERA) for useful discussions on the new experimental designs and the manuscript.Peer reviewe
Love, rights and solidarity: studying children's participation using Honneth's theory of recognition
Recent attempts to theorize childrenâs participation have drawn on a wide range of ideas, concepts and models from political and social theory. The aim of this article is to explore the specific usefulness of Honnethâs theory of a âstruggle for recognitionâ in thinking about this area of practice. The article identifies what is distinctive about Honnethâs theory of recognition, and how it differs from other theories of recognition. It then considers the relevance of Honnethâs conceptual framework to the social position of children, including those who may be involved in a variety of âparticipatoryâ activities.
It looks at how useful Honnethâs ideas are in direct engagement with young peopleâs praxis, drawing on ethnographic research with members of a children and young peopleâs forum. The article concludes by reflecting on the implications of this theoretical approach and the further questions which it opens up for theories of participation and of adultâchild relations more generally
Optical Holonomic Quantum Computer
In this paper the idea of holonomic quantum computation is realized within
quantum optics. In a non-linear Kerr medium the degenerate states of laser
beams are interpreted as qubits. Displacing devices, squeezing devices and
interferometers provide the classical control parameter space where the
adiabatic loops are performed. This results into logical gates acting on the
states of the combined degenerate subspaces of the lasers, producing any one
qubit rotations and interactions between any two qubits. Issues such as
universality, complexity and scalability are addressed and several steps are
taken towards the physical implementation of this model.Comment: 16 pages, 3 figures, REVTE
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