NMR and LDA evidence for spiral magnetic order in the chain cuprate LiCu2O2

We report on {6,7}Li nuclear magnetic resonance measurements of the spin-chain compound LiCu2O2 in the paramagnetic and magnetically ordered states. Below T about 24 K the NMR lineshape presents a clear signature of incommensurate (IC) static modulation of the local magnetic field consistent with an IC spiral modulation of the magnetic moments. {7}Li NMR reveals strong phason-like dynamical fluctuations extending well below 24 K. We hypothesize that a series of phase transitions at 24.2, 22.5, and 9 K reflects a "Devil's staircase" type behavior generic for IC systems. LDA based calculations of exchange integrals reveal a large in-chain frustration leading to a magnetical spiral.Comment: 4 pages, 4 figure

How environment and self-motion combine in neural representations of space

Estimates of location or orientation can be constructed solely from sensory information representing environmental cues. In unfamiliar or sensory-poor environments, these estimates can also be maintained and updated by integrating self-motion information. However, the accumulation of error dictates that updated representations of heading direction and location become progressively less reliable over time, and must be corrected by environmental sensory inputs when available. Anatomical, electrophysiological and behavioural evidence indicates that angular and translational path integration contributes to the firing of head direction cells and grid cells. We discuss how sensory inputs may be combined with self-motion information in the firing patterns of these cells. For head direction cells, direct projections from egocentric sensory representations of distal cues can help to correct cumulative errors. Grid cells may benefit from sensory inputs via boundary vector cells and place cells. However, the allocentric code of boundary vector cells and place cells requires consistent head-direction information in order to translate the sensory signal of egocentric boundary distance into allocentric boundary vector cell firing, suggesting that the different spatial representations found in and around the hippocampal formation are interdependent. We conclude that, rather than representing pure path integration, the firing of head-direction cells and grid cells reflects the interface between self-motion and environmental sensory information. Together with place cells and boundary vector cells they can support a coherent unitary representation of space based on both environmental sensory inputs and path integration signals

Magnetic phase diagram of the frustrated S=1/2 chain magnet LiCu_2O_2

We present the results of the magnetization and dielectric constant measurements on untwinned single crystal samples of the frustrated S=1/2 chain cuprate LiCu_2O_2. Novel magnetic phase transitions were observed. A spin flop transition of the spiral spin plane was observed for the field orientations H||a,b. The second magnetic transition was observed at H~15 T for all three principal field directions. This high field magnetic phase is discussed as a collinear spin-modulated phase which is expected for an S=1/2 nearest-neighbor ferromagnetic and next-nearest-neighbor antiferromagnetic chain system

Neural Competitive Queuing of Ordinal Structure Underlies Skilled Sequential Action.

Fluent retrieval and execution of movement sequences is essential for daily activities, but the neural mechanisms underlying sequence planning remain elusive. Here participants learned finger press sequences with different orders and timings and reproduced them in a magneto-encephalography (MEG) scanner. We classified the MEG patterns for each press in the sequence and examined pattern dynamics during preparation and production. Our results demonstrate the "competitive queuing" (CQ) of upcoming action representations, extending previous computational and non-human primate recording studies to non-invasive measures in humans. In addition, we show that CQ reflects an ordinal template that generalizes across specific motor actions at each position. Finally, we demonstrate that CQ predicts participants' production accuracy and originates from parahippocampal and cerebellar sources. These results suggest that the brain learns and controls multiple sequences by flexibly combining representations of specific actions and interval timing with high-level, parallel representations of sequence position

Improving radiation hardness in space-based Charge-Coupled Devices through the narrowing of the charge transfer channel

Charge-Coupled Devices (CCDs) have been the detector of choice for imaging and spectroscopy in space missions for several decades, such as those being used for the Euclid VIS instrument and baselined for the SMILE SXI. Despite the many positive properties of CCDs, such as the high quantum efficiency and low noise, when used in a space environment the detectors suffer damage from the often-harsh radiation environment. High energy particles can create defects in the silicon lattice which act to trap the signal electrons being transferred through the device, reducing the signal measured and effectively increasing the noise. We can reduce the impact of radiation on the devices through four key methods: increased radiation shielding, device design considerations, optimisation of operating conditions, and image correction. Here, we concentrate on device design operations, investigating the impact of narrowing the charge-transfer channel in the device with the aim of minimising the impact of traps during readout. Previous studies for the Euclid VIS instrument considered two devices, the e2v CCD204 and CCD273, the serial register of the former having a 50 μm channel and the latter having a 20 μm channel. The reduction in channel width was previously modelled to give an approximate 1.6× reduction in charge storage volume, verified experimentally to have a reduction in charge transfer inefficiency of 1.7×. The methods used to simulate the reduction approximated the charge cloud to a sharp-edged volume within which the probability of capture by traps was 100%. For high signals and slow readout speeds, this is a reasonable approximation. However, for low signals and higher readout speeds, the approximation falls short. Here we discuss a new method of simulating and calculating charge storage variations with device design changes, considering the absolute probability of capture across the pixel, bringing validity to all signal sizes and readout speeds. Using this method, we can optimise the device design to suffer minimum impact from radiation damage effects, here using detector development for the SMILE mission to demonstrate the process

The Meat of the Matter: The Effect of Science-based Information on Consumer Perception of Grass-fed Beef

In the United States, there is a growing disconnect between consumers and their food source, leading to a lack of knowledge and trust in the agricultural food system. Urbanization has moved people away from farms, ranches, and food production; and the information consumers seek about their food is filtered through mass and social media. Portrayals of information about food production, specifically beef, from outside the agriculture industry often present polarizing and conflicting information about beef production and its implications for the health and well-being of humans, livestock, and the environment. This adds to consumer confusion and influences purchasing behaviors. Using a quasi-experimental pretest-posttest 2x2 factorial design, we sought to explore consumer (n = 60) perceptions, consumption, and purchasing behaviors of grass-fed beef and determine the effects of four information treatments on overall perception. Descriptive results showed consumers do not have a shared definition pertaining to grass- and grain-fed beef, citing the internet as their most referenced source for information about food and grass-fed beef. Results from a t-test indicated that exposing consumers to an information treatment had a significant effect on environmental impacts, cost, quality/nutrition, and overall perception of grass-fed beef. A between-subjects factorial ANOVA revealed there was no significant difference in perception based on treatment type. Efforts to raise awareness about beef production, on-farm practices, and links between food and grower could be warranted to help enhance the trust and credibility of the industry and bridge the gap between producers and consumers

Exploring Identities of Extension Faculty and Educators as Science Communicators

This research explored the relationship between University of Idaho (UI) Extension educators and faculty’s social identity as science communicators and their most-used communication type. This non-experimental, sequential, mixed-method study with a qualitative priority utilized surveys and interviews to gather data. This paper will focus on the qualitative and mixing components of the study. We used stratified purposive sampling based on location and most used communication type to select participants for interviews and conducted interviews to understand their social identities as science communicators. We identified five main themes: continual development, technology, research dissemination, evaluation for motivation, and community relationships. We employed a cross-case comparison to find relationships between themes and communication type. Science communication identity and communication types have distinct relationships with science communication identity being seen as an adaptable and flexible title. Participants reported diverse motivations for communicating science, but all emphasized their roles in sharing reliable, research-based information with constituents. Participants discussed the value of skill-building and expressed interest in additional training to become more effective science communicators and better meet the needs of the communities they serve. Additional research to understand the constituent perspective is warranted to explore how professionals are using science communication practices to align with the communication preferences of their audiences to achieve intended outcomes. Replicating this study with Extension professionals in other states would provide insight into a national understanding and application of science communication in Extension