How Listing's Law May Emerge from Neural Control of Reactive Saccades

We hypothesize that Listing's Law emerges as a result of two key properties of the saccadic sensory-motor system: 1) The visual sensory apparatus has a 2-D topology and 2) motor synergists are synchronized. The theory is tested by showing that eye attitudes that obey Listing's Law are achieved in a 3-D saccadic control system that translates visual eccentricity into synchronized motor commands via a 2-D spatial gradient. Simulations of this system demonstrate that attitudes assumed by the eye upon accurate foveation tend to obey Listing's Law.Office of Naval Research (N00014-92-J-1309, N00014-95-1-1409); Air Force Office of Scientific Research (90-0083

Selenium and molybdenum enrichment in uranium roll-front deposits of Wyoming and Colorado, USA

Acknowledgements The authors wish to thank Cal VanHolland, Jim Bonner and John Cooper of Ur-Energy (Casper, Wyoming) for their assistance with sampling, data provision and feedback. We are grateful to Adrian Boyce and Alison McDonald of the Isotope Community Support Facility at SUERC for technical support with isotope sample preparation and analyses. Critical comments that greatly improved the manuscript from Samuel Spinks and Marat Abzalov are gratefully acknowledged. Funding This research was supported by a grant from the Natural Environment Research Council (NERC) (NE/M010953/1).Peer reviewedPublisher PD

Youth opportunity spaces in low-emission dairy development in Kenya: Research findings and policy recommendations

The dairy sector in Kenya produces over 4 billion liters of milk per year and supports 1.3 million producer households with a vital contribution to incomes and nutrition. However, total national production fails to meet demand. There is a need for increased efforts to support value chain development growth in the sector. In addition to the potential of dairy to support economic growth, the dairy sector is receiving substantial attention as a pathway to achieve Kenya’s Nationally Determined Contributions (NDCs), commitments to international agreements to reduce greenhouse gas (GHG) emission intensities. Intensification of production would reduce emission intensities by generating a higher volume of milk per unit of GHG emission. However, Kenya’s NDCs specify that the environmental target of GHG emissions reduction should be pursued in accordance with its broader sustainable development agenda. Low-emission development has significant implications for reaching International Sustainable Development Goals; specifically, Decent Work and Economic Growth (SDG #8) and Gender Equality (SDG #5)

Spherulite formation in obsidian lavas in the Aeolian Islands, Italy

The authors wish to gratefully acknowledge Andy Tindle (The Open University) for assistance with EMP analyses, and Richard Darton and David Evans (Keele University) for assistance with XRD and Prof Alun Vaughan and Nicola Freebody (University of Southampton) with Raman analyses. LAB is grateful to Sophie Blanchard for support with MATLAB. The authors acknowledge support from Keele University, and grants from the Mineralogical Society (UK and Ireland) and Volcanic and Magmatic Studies Group. The authors thank Silvio Mollo and Francesca Forni for their detailed and helpful comments.Peer reviewedPublisher PD

Emplacement of the Rocche Rosse rhyolite lava flow (Lipari, Aeolian Islands)

The authors acknowledge Airbus Defence and Space for providing satellite imagery, financial support from Keele University and fieldwork grants from the Mineralogical Society of Great Britain and Ireland and the Volcanic and Magmatic Studies Group. LAB wishes to thank Leanne Patrick and James Watling for fieldwork assistance. The authors are grateful for the thorough and constructive comments from Guido Giordano and an anonymous reviewer, as well as the careful editorial handling of Kathy Cashman and Andrew Harris, which greatly improved this manuscript. Open access via Springer CompactPeer reviewedPublisher PD

Empirical orbit determination using Apollo 14 data

An empirical orbit determination method is shown to yield highly accurate navigation results when applied to lunar orbit tracking data. Regressions and predictions of free flight Apollo 14 tracking data exhibit minimal residual growth, and the solution orbital elements behave in a very consistent manner. Solutions from data acquired during propulsive maneuvers result in degraded predictions. The residual patterns from free flight processing are shown to be consistent from pass to pass and are correlated with lunar topographic features

Artificial life: Discipline or method? Report on a debate held at ECAL99

How can artificial life (AL) advance scientific understanding? Is AL best seen as a new discipline, or as a collection of novel computational methods that can be applied to old problems? And given that the products of AL research range from abstract existence proofs to working robots to detailed simulation models, are there standards of quality or usefulness that can be applied across the whole field? On September 16th, 1999 in Lausanne, Switzerland, a debate on these questions was held as part of the Fifth European Conference on Artificial Life. As the organizers, we wanted to foster a constructive discussion regarding the scientific status, and future, of AL. We were well aware that some of these issues had been raised before (e.g., Miller [2]) but we felt that earlier treatments had perhaps not reached a wide enough audience. The format for the debate consisted of contributions from invited panelists followed by an open discussion. The panelists were Chris Langton, Mark Bedau, Simon Kirby, and Inman Harvey—Hiroaki Kitano was scheduled to participate but regrettably could not attend the conference

Osteocytes and mechanical loading: The Wnt connection

Bone adapts to the mechanical forces that it experiences. Orthodontic tooth movement harnesses the cell‐ and tissue‐level properties of mechanotransduction to achieve alignment and reorganization of the dentition. However, the mechanisms of action that permit bone resorption and formation in response to loads placed on the teeth are incompletely elucidated, though several mechanisms have been identified. Wnt/Lrp5 signalling in osteocytes is a key pathway that modulates bone tissue's response to load. Numerous mouse models that harbour knock‐in, knockout and transgenic/overexpression alleles targeting genes related to Wnt signalling point to the necessity of Wnt/Lrp5, and its localization to osteocytes, for proper mechanotransduction in bone. Alveolar bone is rich in osteocytes and is a highly mechanoresponsive tissue in which components of the canonical Wnt signalling cascade have been identified. As Wnt‐based agents become clinically available in the next several years, the major challenge that lies ahead will be to gain a more complete understanding of Wnt biology in alveolar bone so that improved/expedited tooth movement becomes a possibility