Beaver and Aspen: Synergy Among Keystone Species

In the West, climate change is likely to increase the frequency, intensity, and duration of drought. Restoration of soils and water storage capacity can help create resilient uplands and riverscapes (i.e., streams and the valley bottoms). Over the past two centuries, common land uses, the removal of beaver and wood, straightening of streams, and damage to riparian areas have created simplified, structurally starved, riverscapes. Degraded streams are very efficient at transporting water, sediment, and nutrients downstream. Aspen forests are also biological hotspots that have been degraded by past land uses such as overbrowsing ungulates, land clearing, fire suppression, and outright removal in favor of timber species. Loss of riverscape and aspen habitats has a disproportionate impact on biodiversity and landscape resilience. When aspen occur in or near riverscapes they are a preferred food and building material for beavers. Beaver, in-turn, can stimulate aspen regeneration, both through cutting and restoring hydrologic function in riparian areas. Adding beavers can reinstate riparian processes, increase aspen growth and diversity that extends to uplands, and buffer ecosystem sensitivity to extended drought

Propagule Pressure and Stream Characteristics Influence Introgression: Cutthroat and Rainbow Trout in British Columbia

Hybridization and introgression between introduced and native salmonids threaten the continued persistence of many inland cutthroat trout species. Environmental models have been developed to predict the spread of introgression, but few studies have assessed the role of propagule pressure. We used an extensive set of fish stocking records and geographic information system (GIS) data to produce a spatially explicit index of potential propagule pressure exerted by introduced rainbow trout in the Upper Kootenay River, British Columbia, Canada. We then used logistic regression and the information-theoretic approach to test the ability of a set of environmental and spatial variables to predict the level of introgression between native westslope cutthroat trout and introduced rainbow trout. Introgression was assessed using between four and seven co-dominant, diagnostic nuclear markers at 45 sites in 31 different streams. The best model for predicting introgression included our GIS propagule pressure index and an environmental variable that accounted for the biogeoclimatic zone of the site (r2¼0.62). This model was 1.4 times more likely to explain introgression than the next-best model, which consisted of only the propagule pressure index variable. We created a composite model based on the model-averaged results of the seven top models that included environmental, spatial, and propagule pressure variables. The propagule pressure index had the highest importance weight (0.995) of all variables tested and was negatively related to sites with no introgression. This study used an index of propagule pressure and demonstrated that propagule pressure had the greatest influence on the level of introgression between a native and introduced trout in a human-induced hybrid zone

Conditional beam splitting attack on quantum key distribution

We present a novel attack on quantum key distribution based on the idea of adaptive absorption [calsam01]. The conditional beam splitting attack is shown to be much more efficient than the conventional beam spitting attack, achieving a performance similar to the, powerful but currently unfeasible, photon number splitting attack. The implementation of the conditional beam splitting attack, based solely on linear optical elements, is well within reach of current technology.Comment: Submitted to Phys. Rev.

The effects of low-intensity blood flow restricted exercise compared with conventional resistance training on the clinical outcomes of active UK military personnel following a 3-week in-patient rehabilitation programme: protocol for a randomized controlled feasibility study

**Background** A challenge for rehabilitation practitioners lies in designing optimal exercise programmes that facilitate musculoskeletal (MSK) adaptations whilst simultaneously accommodating biological healing and the safe loading of an injured limb. A growing body of evidence supports the use of resistance training at a reduced load in combination with blood flow restriction (BFR) to enhance hypertrophic and strength responses in skeletal muscle. In-patient rehabilitation has a long tradition in the UK Military, however, the efficacy of low intensity (LI) BFR training has not been tested in this rehabilitation setting. The aims of this study are to determine (1) the feasibility of a randomised controlled trial (RCT) investigating LI-BFR training in a residential, multidisciplinary treatment programme and (2) provide preliminary data describing the within and between-group treatment effects of a LI-BFR intervention and a conventional resistance training group in military personnel. **Methods** This is a single-blind randomised controlled feasibility study. A minimum of 28 lower-limb injured UK military personnel, aged 18 to 50 years, attending rehabilitation at the UK Defence Medical Rehabilitation Centre (DMRC) will be recruited into the study. After completion of baseline measurements, participants will be randomised in a 1:1 ratio to receive 3 weeks (15 days) of intensive multidisciplinary team (MDT) in-patient rehabilitation. Group 1 will receive conventional resistance training 3 days per week. Group 2 will perform twice daily LI-BFR training. Both groups will also undertake the same common elements of the existing MDT programme. Repeat follow-up assessments will be undertaken upon completion of treatment. Group 2 participants will be asked to rate their pain response to LI-BFR training every five sessions. **Discussion** The results will provide information on the feasibility of a full-scale RCT. Recommendations for an adequately powered study to determine the efficacy of LI-BFR training during in-patient rehabilitation can then be made. The study may also provide insights into the potential effectiveness of LI-BFR training as a novel exercise modality to induce muscle adaptations in the absence of high mechanical loading of the lower-limb

Investigating Perceptual Congruence Between Data and Display Dimensions in Sonification

The relationships between sounds and their perceived meaning and connotations are complex, making auditory perception an important factor to consider when designing sonification systems. Listeners often have a mental model of how a data variable should sound during sonification and this model is not considered in most data:sound mappings. This can lead to mappings that are difficult to use and can cause confusion. To investigate this issue, we conducted a magnitude estimation experiment to map how roughness, noise and pitch relate to the perceived magnitude of stress, error and danger. These parameters were chosen due to previous findings which suggest perceptual congruency between these auditory sensations and conceptual variables. Results from this experiment show that polarity and scaling preference are dependent on the data:sound mapping. This work provides polarity and scaling values that may be directly utilised by sonification designers to improve auditory displays in areas such as accessible and mobile computing, process-monitoring and biofeedback

Low-Load Resistance Training With Blood Flow Restriction Improves Clinical Outcomes in Musculoskeletal Rehabilitation: A Single-Blind Randomized Controlled Trial.

Background: There is growing evidence to support the use of low-load blood flow restriction (LL-BFR) exercise in musculoskeletal rehabilitation. Purpose: The purpose of this study was to evaluate the efficacy and feasibility of low-load blood flow restricted (LL-BFR) training versus conventional high mechanical load resistance training (RT) on the clinical outcomes of patient's undergoing inpatient multidisciplinary team (MDT) rehabilitation. Study design: A single-blind randomized controlled study. Methods: Twenty-eight lower-limb injured adults completed a 3-week intensive MDT rehabilitation program. Participants were randomly allocated into a conventional RT (3-days/week) or twice-daily LL-BFR training group. Outcome measurements were taken at baseline and 3-weeks and included quadriceps and total thigh muscle cross-sectional area (CSA) and volume, muscle strength [five repetition maximum (RM) leg press and knee extension test, isometric hip extension], pain and physical function measures (Y-balance test, multistage locomotion test-MSLT). Results: A two-way repeated measures analysis of variance revealed no significant differences between groups for any outcome measure post-intervention (p > 0.05). Both groups showed significant improvements in mean scores for muscle CSA/volume, 5-RM leg press, and 5-RM knee extension (p < 0.01) after treatment. LL-BFR group participants also demonstrated significant improvements in MSLT and Y-balance scores (p < 0.01). The Pain scores during training reduced significantly over time in the LL-BFR group (p = 0.024), with no adverse events reported during the study. Conclusion: Comparable improvements in muscle strength and hypertrophy were shown in LL-BFR and conventional training groups following in-patient rehabilitation. The LL-BFR group also achieved significant improvements in functional capacity. LL-BFR training is a rehabilitation tool that has the potential to induce positive adaptations in the absence of high mechanical loads and therefore could be considered a treatment option for patients suffering significant functional deficits for whom conventional loaded RT is contraindicated. Trial Registration: ISRCTN Reference: ISRCTN63585315, dated 25 April 2017

Revisiting consistency conditions for quantum states of systems on closed timelike curves: an epistemic perspective

There has been considerable recent interest in the consequences of closed timelike curves (CTCs) for the dynamics of quantum mechanical systems. A vast majority of research into this area makes use of the dynamical equations developed by Deutsch, which were developed from a consistency condition that assumes that mixed quantum states uniquely describe the physical state of a system. We criticise this choice of consistency condition from an epistemic perspective, i.e., a perspective in which the quantum state represents a state of knowledge about a system. We demonstrate that directly applying Deutsch's condition when mixed states are treated as representing an observer's knowledge of a system can conceal time travel paradoxes from the observer, rather than resolving them. To shed further light on the appropriate dynamics for quantum systems traversing CTCs, we make use of a toy epistemic theory with a strictly classical ontology due to Spekkens and show that, in contrast to the results of Deutsch, many of the traditional paradoxical effects of time travel are present.Comment: 10 pages, 6 figures, comments welcome; v2 added references and clarified some points; v3 published versio

Constraints on Intervening Stellar Populations Toward the Large Magellanic Cloud

The suggestion by Zaritsky & Lin that a vertical extension of the red clump feature in color-magnitude diagrams of the Large Magellanic Cloud (LMC) is consistent with a significant population of foreground stars to the LMC that could account for the observed microlensing optical depth has been challenged by various investigators. We respond by (1) examining each of the challenges presented and (2) presenting new photometric and spectroscopic data. We conclude that although the CMD data do not mandate the existence of a foreground population, they are entirely consistent with a foreground population associated with the LMC that contributes significantly (~ 50%) to the observed microlensing optical depth. From our new data, we conclude that <~ 40% of the VRC stars are young, massive red clump stars because (1) synthetic color-magnitude diagrams created using the star formation history derived indepdently from HST data suggest that < 50% of the VRC stars are young, massive red clump stars, (2) the angular distribution of the VRC stars is more uniform than that of the young (age < 1 Gyr) main sequence stars, and (3) the velocity dispersion of the VRC stars in the region of the LMC examined by ZL is inconsistent with the expectation for a young disk population. Each of these arguments is predicated on assumptions and the conclusions are uncertain. Therefore, an exact determination of the contribution to the microlensing optical depth by the various hypothesized foreground populations, and the subsequent conclusions regarding the existence of halo MACHOs, requires a detailed knowledge of many complex astrophysical issues, such as the IMF, star formation history, and post-main sequence stellar evolution. (abridged)Comment: Scheduled for publication in AJ in May 199

Pedagogy: the silent partner in early years learning

This paper sets out to look critically at the influences on pedagogy in early years education, at the ways in which it is enacted in practice and the pedagogical perspectives held by practitioners. The aim of the paper is to explore the current state of understanding and suggest areas to be included in an agenda for future research. The factors that influence practitioners’ actions are reviewed and the consensus around child-centredness and play is challenged. Findings from two studies of pedagogy in action in the early years are presented and examined in terms of socio-cultural theory and its implications for practice. The first of these studies draws attention to the varied nature of pedagogical interactions that support learning while the second looks at the experience of pedagogical innovation. The need for researchers and practitioners to find effective ways of communicating and working together is stressed throughout the paper