Linear Self-Motion Cues Support the Spatial Distribution and Stability of Hippocampal Place Cells

The vestibular system provides a crucial component of place-cell and head-direction cell activity [1-7]. Otolith signals are necessary for head-direction signal stability and associated behavior [8, 9], and the head-direction signal's contribution to parahippocampal spatial representations [10-14] suggests that place cells may also require otolithic information. Here, we demonstrate that self-movement information from the otolith organs is necessary for the development of stable place fields within and across sessions. Place cells in otoconia-deficient tilted mice showed reduced spatial coherence and formed place fields that were located closer to environmental boundaries, relative to those of control mice. These differences reveal an important otolithic contribution to place-cell functioning and provide insight into the cognitive deficits associated with otolith dysfunction

Hip Torque Is a Mechanistic Link Between Sprint Acceleration and Maximum Velocity Performance: A Theoretical Perspective

Sprinting performance is critical for a variety of sports and competitive activities. Prior research has demonstrated correlations between the limits of initial acceleration and maximum velocity for athletes of different sprinting abilities. Our perspective is that hip torque is a mechanistic link between these performance limits. A theoretical framework is presented here that provides estimates of sprint acceleration capability based on thigh angular acceleration and hip torque during the swing phase while running at maximum velocity. Performance limits were calculated using basic anthropometric values (body mass and leg length) and maximum velocity kinematic values (contact time, thigh range of motion, and stride frequency) from previously published sprint data. The proposed framework provides a mechanistic link between maximum acceleration and maximum velocity, and also explains why time constant values (tau, ratio of the velocity limit to acceleration limit) for sprint performance curves are generally close to one-second even for athletes with vastly different sprinting abilities. This perspective suggests that specific training protocols targeted to improve thigh angular acceleration and hip torque capability will benefit both acceleration and maximum velocity phases of a sprint

A pilot study of the S-MAP (Solutions for Medications Adherence Problems) intervention for older adults prescribed polypharmacy in primary care: Study protocol

Background: Adhering to multiple medications as prescribed is challenging for older patients (aged ≥ 65 years) and a difficult behaviour to improve. Previous interventions designed to address this have been largely complex in nature but have shown limited effectiveness and have rarely used theory in their design. It has been recognised that theory ('a systematic way of understanding events or situations') can guide intervention development and help researchers better understand how complex adherence interventions work. This pilot study aims to test a novel community pharmacy-based intervention that has been systematically developed using the Theoretical Domains Framework (12-domain version) of behaviour change. Methods: As part of a non-randomised pilot study, pharmacists in 12 community pharmacies across Northern Ireland (n = 6) and London, England (n = 6), will be trained to deliver the intervention to older patients who are prescribed ≥ 4 regular medicines and are non-adherent (self-reported). Ten patients will be recruited per pharmacy (n = 120) and offered up to four tailored one-to-one sessions, in the pharmacy or via telephone depending on their adherence, over a 3-4-month period. Guided by an electronic application (app) on iPads, the intervention content will be tailored to each patient's underlying reasons for non-adherence and mapped to the most appropriate solutions using established behaviour change techniques. This study will assess the feasibility of collecting data on the primary outcome of medication adherence (self-report and dispensing data) and secondary outcomes (health-related quality of life and unplanned hospitalisations). An embedded process evaluation will assess training fidelity for pharmacy staff, intervention fidelity, acceptability to patients and pharmacists and the intervention's mechanism of action. Process evaluation data will include audio-recordings of training workshops, intervention sessions, feedback interviews and patient surveys. Analysis will be largely descriptive. Discussion: Using pre-defined progression criteria, the findings from this pilot study will guide the decision whether to proceed to a cluster randomised controlled trial to test the effectiveness of the S-MAP intervention in comparison to usual care in community pharmacies. The study will also explore how the intervention components may work to bring about change in older patients' adherence behaviour and guide further refinement of the intervention and study procedures. Trial registration: This study is registered at ISRCTN: https://doi.org/10.1186/ISRCTN7383153

Structural constraints on the exhumation of the Tso Morari Dome, NW Himalaya

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2005.Includes bibliographical references (p. 35-38).The Tso Morari culmination in the Ladakh region of northwest India is a large (>3,000 km²) structural dome cored by coesite-bearing rocks of Indian continental crustal affinity. As one of only two localities in the Himalaya where ultrahigh-pressure rocks have been found, the culmination offers important insights into the orogenic processes responsible for exhumation of subducted continental crust. New, 1:50,000 scale geologic mapping and structural analysis in the Tso Morari area reveals evidence for five distinct deformational events. Rather than simple, one step processes envisioned by investigators in many ultrahigh-pressure terrains, exhumation of the Tso Morari culmination was a polyphase process. From >90 km to mid-crustal depths, exhumation was accommodated by a diachronous set of rooted, ductile, extensional detachments that were active [approx.] 53-40 Ma. Beginning in the Late Oligocene, continued exhumation occurred by progressive unroofing along a younger, brittle-ductile detachment. Through a rolling-hinge mechanism similar to that proposed for many metamorphic core complexes of the North American Cordillera, this unroofing led to the development of the culmination into a NW trending structural dome.(cont.) More recently, N-S-striking normal faults accommodated continued upper crustal extension throughout much of the remainder of Cenozoic time, despite the culmination's setting in the Himalayan collisional orogen.by Ryan J. Clark.S.M

Human Sprint Running Mechanics: Do Right and Left Legs Apply Equal Ground Forces?

Introduction: A growing body of research has focused on between-leg asymmetry as a critical factor for athletic performance and dysfunction. Specifically, various measures of between-leg asymmetry during running have been investigated in both healthy and injured populations. However, while the most important factor for running performance is the magnitude and rate of ground force application, it is not known whether the right and left legs typically apply equal ground forces at faster running speeds. Objective: In a healthy population of athletic female participants, we aimed to: 1) compare the mechanics of ground force application between right and left legs during moderate and top speed running, and 2) evaluate if the right vs. left leg asymmetries observed at intermediate speeds are more pronounced at faster speeds. Hypothesis: We hypothesized that the forces applied by the right and left legs of healthy athletes would agree to within 10% or less at both moderate and top speed. Participants: Nine female intercollegiate soccer players volunteered for the study (age: 19.4 ± 1.0 years, height: 1.72 ± 0.04 m, mass: 69.0 ± 7.2 kg). Data Collection: Ground force data was acquired at 1,000 Hz using a custom high-speed, three-axis force treadmill (AMTI, Watertown, MA). Data was analyzed for trials at 5.0 m•s-1 and each individual’s top speed. Top speed was defined as the fastest speed where the participant could complete eight consecutive steps on the treadmill without drifting backward more than 0.2 m. Outcome Measures: Ground contact time, vertical force, and vertical impulse were analyzed. Vertical force was normalized to body weight (Wb) and vertical impulse was calculated in body weight • seconds (Wb•s). For all trials, these variables were averaged for right vs. left footfalls, and percentage difference was calculated to quantify between-leg asymmetry. Results: Top speeds ranged from 7.21 to 8.26 m•s-1 (7.83 ± 0.38 m•s-1). At 5.0 m•s-1, the mean between-leg asymmetry was 2.3 ± 1.2 % for ground contact time, 1.9 ± 1.3 % for vertical force, and 2.3 ± 1.9 % for vertical impulse. At top speed, the mean between-leg asymmetry was 3.5 ± 2.8 % for ground contact time, 5.5 ± 3.0 % for vertical force, and 8.3 ± 4.8 % for vertical impulse. Conclusions: We conclude that the right and left legs apply ground force similarly during moderate and top-speed sprint running in healthy female athletes

A general relationship links gait mechanics and running ground reaction forces

The relationship between gait mechanics and running ground reaction forces is widely regarded as complex. This viewpoint has evolved primarily via efforts to explain the rising edge of vertical force– time waveforms observed during slow human running. Existing theoretical models do provide good rising-edge fits, but require more than a dozen input variables to sum the force contributions of four or more vague components of the body’s total mass (mb). Here, we hypothesized that the force contributions of two discrete body mass components are sufficient to account for vertical ground reaction force– time waveform patterns in full (stance foot and shank, m1=0.08mb; remaining mass, m2=0.92mb). We tested this hypothesis directly by acquiring simultaneous limb motion and ground reaction force data across a broad range of running speeds (3.0–11.1 m s−1 ) from 42 subjects who differed in body mass (range: 43–105 kg) and foot-strike mechanics. Predicted waveforms were generated from our two-mass model using body mass and three stride-specific measures: contact time, aerial time and lower limb vertical acceleration during impact. Measured waveforms (N=500) differed in shape and varied by more than twofold in amplitude and duration. Nonetheless, the overall agreement between the 500 measured waveforms and those generated independently by the model approached unity (R2 =0.95 ±0.04, mean±s.d.), with minimal variation across the slow, medium and fast running speeds tested (ΔR2 ≤0.04), and between rear-foot (R2 =0.94±0.04, N=177) versus fore-foot (R2 =0.95±0.04, N=323) strike mechanics. We conclude that the motion of two anatomically discrete components of the body’s mass is sufficient to explain the vertical ground reaction force–time waveform patterns observed during human running

Attitude Control and Orbit Determination of a Crewed Spacecraft with Lunar Lander in near Rectilinear Halo Orbit

NASA's Gateway program plans to place a crew-tended spacecraft in cislunar Near Rectilinear Halo Orbit (NRHO). The craft will support arrivals of crews in Orion and the undocking and return of a crewed lunar lander. The impact to at-titude control of a Gateway with the addition of a lunar lander is investigated. Perturbations from Orion and a lander's docking and undocking from the Gate-way are considered. Deep Space Network (DSN) tracking is supplemented with optical measurements to lunar north pole craters to analyze the possible benefit in solution accuracy and/or DSN scheduling relief

Mediating the GM Foods Debate: Lessons from the Enduring Conflict Framework

Critics of the commercialization of Genetically Modified (GM) foods in Canada and the United States oppose the economic and political forces that create and approve the technology: the industry that develops it and the governments that approve its use. The conventional narrative pits the concerned public, labeled anti-GM, against the pro-GM interests of industry supported by business-friendly governments. Based on this binary view of the interests and motivations of stakeholders, conflict betwee

Calibration and Cross-Validation of Accelerometery for Estimating Movement Skills in Children Aged 8-12 Years

This study sought to calibrate triaxial accelerometery, worn on both wrists, waist and both ankles, during children’s physical activity (PA), with particular attention to object control motor skills performed at a fast and slow cadence, and to cross-validate the accelerometer cut-points derived from the calibration using an independent dataset. Twenty boys (10.1 ±1.5 years) undertook seven, five-minute bouts of activity lying supine, standing, running (4.5kmph−1) instep passing a football (fast and slow cadence), dribbling a football (fast and slow cadence), whilst wearing five GENEActiv accelerometers on their non-dominant and dominant wrists and ankles and waist. VO2 was assessed concurrently using indirect calorimetry. ROC curve analysis was used to generate cut-points representing sedentary, light and moderate PA. The cut-points were then cross-validated using independent data from 30 children (9.4 ± 1.4 years), who had undertaken similar activities whilst wearing accelerometers and being assessed for VO2. GENEActiv monitors were able to discriminate sedentary activity to an excellent level irrespective of wear location. For moderate PA, discrimination of activity was considered good for monitors placed on the dominant wrist, waist, non-dominant and dominant ankles but fair for the non-dominant wrist. Applying the cut-points to the cross-validation sample indicated that cut-points validated in the calibration were able to successfully discriminate sedentary behaviour and moderate PA to an excellent standard and light PA to a fair standard. Cut-points derived from this calibration demonstrate an excellent ability to discriminate children’s sedentary behaviour and moderate intensity PA comprising motor skill activity.N/