Autophage engines: towards a throttleable solid motor

This paper describes the instrumented test firing of a rocket that seeks to combine the throttleability of a liquid-fueled engine with the simplicity of a solid motor. The concept is that a differentiated fuel and oxidizer rod is forced into a vaporization unit where its constituents transition into separate propellant gases, which are then mixed in a combustion chamber. The vaporization unit is heated by the combustion, and the throttle setting is adjusted by changing the force used to drive the solid propellant rod into the vaporizer, which naturally influences the propellant feed rate. In experiments using a solid propellant rod consisting of polypropylene fuel and a 1∶1.5 mixture of NH4ClO4 and NH4NO3 oxidizer, operations have been sustained for around 60 s. During testing, using propellant feed forces of between 250 and 900 N, propellant feed rates of between 100 and 300 mm/min have been achieved, which are in turn correlated to chamber pressures of between approximately 300 and 700 kPa. These correlated cycles of control input (the feed force), throttle response (the propellant feed rate), and implied thrust (the chamber pressure) demonstrate, for the first time, a simple solid rocket that can be throttled in real time

Long-term deficits in cortical circuit function after asphyxial cardiac arrest and resuscitation in developing rats

AbstractCardiac arrest is a common cause of global hypoxic-ischemic brain injury. Poor neurologic outcome among cardiac arrest survivors results not only from direct cellular injury but also from subsequent long-term dysfunction of neuronal circuits. Here, we investigated the long-term impact of cardiac arrest during development on the function of cortical layer IV (L4) barrel circuits in the rat primary somatosensory cortex. We used multielectrode single-neuron recordings to examine responses of presumed excitatory L4 barrel neurons to controlled whisker stimuli in adult (8 ± 2-mo-old) rats that had undergone 9 min of asphyxial cardiac arrest and resuscitation during the third postnatal week. Results indicate that responses to deflections of the topographically appropriate principal whisker (PW) are smaller in magnitude in cardiac arrest survivors than in control rats. Responses to adjacent whisker (AW) deflections are similar in magnitude between the two groups. Because of a disproportionate decrease in PW-evoked responses, receptive fields of L4 barrel neurons are less spatially focused in cardiac arrest survivors than in control rats. In addition, spiking activity among L4 barrel neurons is more correlated in cardiac arrest survivors than in controls. Computational modeling demonstrates that experimentally observed disruptions in barrel circuit function after cardiac arrest can emerge from a balanced increase in background excitatory and inhibitory conductances in L4 neurons. Experimental and modeling data together suggest that after a hypoxic-ischemic insult, cortical sensory circuits are less responsive and less spatially tuned. Modulation of these deficits may represent a therapeutic approach to improving neurologic outcome after cardiac arrest.</jats:p

Knowing when to talk? Plant genome editing as a site for pre-engagement institutional reflexivity

This is the final version. Available on open access from SAGE Publications via the DOI in this recordCitizen and stakeholder engagement is frequently portrayed as vital for socially accountable science policy but there is a growing understanding of how institutional dynamics shape engagement exercises in ways that prevent them from realising their full potential. Limited attention has been devoted to developing the means to expose institutional features, allow policy-makers to reflect on how they will shape engagement and respond appropriately. Here, therefore, we develop and test a methodological framework to facilitate pre-engagement institutional reflexivity with one of the United Kingdom’s eminent science organisations as it grappled with a new, high-profile and politicised technology, genome editing. We show how this approach allowed policy-makers to reflect on their institutional position and enrich decision-making at a time when they faced pressure to legitimate decisions with engagement. Further descriptions of such pre-engagement institutional reflexivity are needed to better bridge theory and practice in the social studies of science.Engineering and Physical Sciences Research Council (EPSRC)Biotechnology and Biological Sciences Research Council (BBSRC

Exploring implicit and explicit aspects of sense of agency.

Sense of agency refers to the sense of initiating and controlling actions in order to influence events in the outside world. Recently, a distinction between implicit and explicit aspects of sense of agency has been proposed, analogous to distinctions found in other areas of cognition, notably learning. However, there is yet no strong evidence supporting separable implicit and explicit components of sense of agency. The so-called 'Perruchet paradigm' offers one of the few convincing demonstrations of separable implicit and explicit learning systems. We adopted this approach to evaluate the implicit-explicit distinction in the context of a simple task in which outcomes were probabilistically caused by actions. In line with our initial predictions, we found evidence of a dissociation. We discuss the implications of this result for theories of sense of agency

From QASC to QASCIP: successful Australian translational scale-up and spread of a proven intervention in acute stroke using a prospective pre-test/post-test study design

Objectives: To embed an evidence-based intervention to manage FEver, hyperglycaemia (Sugar) and Swallowing (the FeSS protocols) in stroke, previously demonstrated in the Quality in Acute Stroke Care (QASC) trial to decrease 90-day death and dependency, into all stroke services in New South Wales (NSW), Australia’s most populous state. Design: Pre-test/post-test prospective study. Setting: 36 NSW stroke services. Methods: Our clinical translational initiative, the QASC Implementation Project (QASCIP), targeted stroke services to embed 3 nurse-led clinical protocols (the FeSS protocols) into routine practice. Clinical champions attended a 1-day multidisciplinary training workshop and received standardised educational resources and ongoing support. Using the National Stroke Foundation audit collection tool and processes, patient data from retrospective medical record self-reported audits for 40 consecutive patients with stroke per site pre-QASCIP (1 July 2012 to 31 December 2012) were compared with prospective self-reported data from 40 consecutive patients with stroke per site post-QASCIP (1 November 2013 to 28 February 2014). Inter-rater reliability was substantial for 10 of 12 variables. Primary outcome measures: Proportion of patients receiving care according to the FeSS protocols pre-QASCIP to post-QASCIP. Results: All 36 (100%) NSW stroke services participated, nominating 100 site champions who attended our educational workshops. The time from start of intervention to completion of post-QASCIP data collection was 8 months. All (n=36, 100%) sites provided medical record audit data for 2144 patients (n=1062 pre-QASCIP; n=1082 post-QASCIP). Pre-QASCIP to post-QASCIP, proportions of patients receiving the 3 targeted clinical behaviours increased significantly: management of fever (pre: 69%; post: 78%; p=0.003), hyperglycaemia (pre: 23%; post: 34%; p=0.0085) and swallowing (pre: 42%; post: 51%; p=0.033). Conclusions: We obtained unprecedented statewide scale-up and spread to all NSW stroke services of a nurse-led intervention previously proven to improve long-term patient outcomes. As clinical leaders search for strategies to improve quality of care, our initiative is replicable and feasible in other acute care settings