3,254 research outputs found
A plan for spacecraft automated rendezvous
An automated rendezvous approach has been developed that utilizes advances in technology to reduce real-time/near real-time flight operations support personnel to an acceptable level that is near the minimum without jeopardizing the success of the mission. The on-board flight targeting uses a rule-based system to select the pursuit vehicle phasing orbits and uses precise navigation updates from the pursuit/target spacecraft made possible by the global positioning system receivers/processors on both spacecraft to adjust the phasing orbits and achieve rendezvous. The ascent-to-orbit targeting for the pursuit vehicle has been successfully decoupled from the on-orbit orbit transfer phasing targeting. Typical launch window data have been developed for the heavy lift launch vehicle and cargo transfer vehicle for a Space Station Freedom rendezvous mission
Phenazepam: More information coming in from the cold
Phenazepam is a 1-4 benzodiazepine that was developed in 1975 in the former USSR this article updates what is known about the pharmacokinetics of Phenazepam
Enhancing Perception of Complex Sculptural Forms using Interactive Real-time Ray tracing
This paper looks at experiments into using real-time ray tracing to significantly enhance shape perception of complex three-dimensional digitally created structures. The author is a computational artist whose artistic practice explores the creation of intricate organic three-dimensional forms using simulation of morphogenesis. The generated forms are often extremely detailed, comprising tens of millions of cellular primitives. This often makes depth perception of the resulting structures difficult. His practice has explored various techniques to create presentable artefacts from the data, including high resolution prints, animated videos, stereoscopic installations, 3D printing and virtual reality.
The author uses ray tracing techniques to turn the 3D data created from his morphogenetic simulations into visible artefacts. This is typically a time-consuming process, taking from seconds to minutes to create a single frame. The latest generation of graphics processing units offer dedicated hardware to accelerate ray tracing calculations. This potentially allows the generation of ray traced images, including self-shadowed complex structures and multiple levels of transparency, from new viewpoints at frame rates capable of real-time interaction. The author presents the results of his experiments using this technology with the aim of providing significantly enhanced perception of his generated three-dimensional structures by allowing user-initiated interaction to generate novel views, and utilizing depth cues such as stereopsis, depth from motion and defocus blurring.
The intention is for these techniques to be usable to present new exhibitable works in a gallery context
A panel model for predicting the diversity of internal temperatures from English dwellings
Using panel methods, a model for predicting daily mean internal temperature demand across a heterogeneous domestic building stock is developed. The model offers an important link that connects building stock models to human behaviour. It represents the first time a panel model has been used to estimate the dynamics of internal temperature demand from the natural daily fluctuations of external temperature combined with important behavioural, socio-demographic and building efficiency variables. The model is able to predict internal temperatures across a heterogeneous building stock to within ~0.71°C at 95% confidence and explain 45% of the variance of internal temperature between dwellings. The model confirms hypothesis from sociology and psychology that habitual behaviours are important drivers of home energy consumption. In addition, the model offers the possibility to quantify take-back (direct rebound effect) owing to increased internal temperatures from the installation of energy efficiency measures. The presence of thermostats or thermostatic radiator valves (TRV) are shown to reduce average internal temperatures, however, the use of an automatic timer is statistically insignificant. The number of occupants, household income and occupant age are all important factors that explain a proportion of internal temperature demand. Households with children or retired occupants are shown to have higher average internal temperatures than households who do not. As expected, building typology, building age, roof insulation thickness, wall U-value and the proportion of double glazing all have positive and statistically significant effects on daily mean internal temperature. In summary, the model can be used as a tool to predict internal temperatures or for making statistical inferences. However, its primary contribution offers the ability to calibrate existing building stock models to account for behaviour and socio-demographic effects making it possible to back-out more accurate predictions of domestic energy demand
Neuroserpin: a serpin to think about
Proteinases and their inhibitors play important roles in neural development, homeostasis and disease. Neuroserpin is a member of the serine proteinase inhibitor (serpin) superfamily that is secreted from the growth cones of neurons and inhibits the enzyme tissue-type plasminogen activator (tPA). The temporal and spatial pattern of neuroserpin expression suggests a role in synaptogenesis and is most prominent in areas of the brain that participate in learning, memory and behaviour. Neuroserpin also provides neuronal protection in pathologies such as cerebral ischaemia and epilepsy by preventing excessive activity of tPA. Point mutations in neuroserpin cause aberrant conformational transitions and the formation of loop-sheet polymers that are retained within the endoplasmic reticulum of neurons, forming inclusion bodies that underlie an autosomal dominant dementia that we have called familial encephalopathy with neuroserpin inclusion bodies or FENIB. We review here the role of neuroserpin and other proteinase inhibitors in brain development, function and disease
Picoheterotroph (Bacteria and Archaea) biomass distribution in the global ocean
We compiled a database of 39 766 data points consisting of flow cytometric and microscopical measurements of picoheterotroph abundance, including both Bacteria and Archaea. After gridding with 1° spacing, the database covers 1.3% of the ocean surface. There are data covering all ocean basins and depths except the Southern Hemisphere below 350m or from April until June. The average picoheterotroph biomass is 3.9 ± 3.6 µg Cl-1 with a 20-fold decrease between the surface and the deep sea. We estimate a total ocean inventory of about 1.3 × 1029 picoheterotroph cells. Surprisingly, the abundance in the coastal regions is the same as at the same depths in the open ocean. Using an average of published open ocean measurements for the conversion from abundance to carbon biomass of 9.1 fg cell-1, we calculate a picoheterotroph carbon inventory of about 1.2 Pg C. The main source of uncertainty in this inventory is the conversion factor from abundance to biomass. Picoheterotroph biomass is ? 2 times higher in the tropics than in the polar oceans
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'I was so done in that I just recognized it very plainly, "You need to do something"': Men's narratives of struggle, distress and turning to meditation
Traditional masculinities can mean men are unable or unwilling to deal constructively with distress. However, researchers increasingly acknowledge that men and masculinities (including hegemonic styles) are diverse. Moreover, men can positively manage their well-being, although little research explores how they do so. Uniquely, our study sought to find men who report finding ways to care for themselves to examine narratives about how such self-care originated. We aimed to do this by exploring issues underpinning men’s journeys towards meditation, focusing on implications for well-being. In-depth interviews were conducted in 2009 with 30 meditators, selected using principles of maximum variation sampling, and analysed with a modified ‘constant comparison’ approach. Men’s journeys towards meditation were fraught with difficulties. Men described crossing a threshold from boyhood into ‘manhood’ where they encountered traditional forms of masculinity (e.g. stoicism), and most described subsequent strategies to disconnect from emotions. While men eventually found ways to engage more constructively with their emotions and well-being, this article explores the struggle and distress of their journeys
‘It’s about wholeness. I love my awesomeness and I love my flawesomeness’: An IPA analysis of coaching with the shadow in mind
Difficult emotions and cognitive states are recognised in second wave positive psychology as being a gold mine for personal growth. The growing body of knowledge in positive psychology gives coaching psychologists a perimeter to work with, whilst archetypal shadow analysis, rooted in Jung’s teachings, gives depth and insight. While definitions of coaching vary considerably, it can be argued to function as shining a light onto things that are hidden for the client, thereby bringing wholeness and clarity. Interpretive phenomenological analysis was used to analyse coaching with the shadow in mind, where this work became defined as looking at parts that are hidden, suppressed, unowned and unacknowledged by us and others. Semi-structured interviews were conducted with four professional coaches. Three higher order themes were identified: the coach’s personal journey through the shadow, what a shadow coach does and the client’s journey into the shadow. These themes may generate insight into this paradigm of coaching for the first time and is an important step in the ongoing integration of second wave positive psychology and coaching psychology
Sargasso Sea phosphorus biogeochemistry : an important role for dissolved organic phosphorus (DOP)
© The Authors, 2010. This article is distributed under the terms of the Creative Commons Attribution 3.0 License. The definitive version was published in Biogeosciences 7 (2010): 695-710, doi: 10.5194/bg-7-695-2010Inorganic phosphorus (SRP) concentrations in the subtropical North Atlantic are some of the lowest in the global ocean and have been hypothesized to constrain primary production. Based upon data from several transect cruises in this region, it has been hypothesized that dissolved organic phosphorus (DOP) supports a significant fraction of primary production in the subtropical North Atlantic. In this study, a time-series of phosphorus biogeochemistry is presented for the Bermuda Atlantic Time-series Study site, including rates of phosphorus export. Most parameters have a seasonal pattern, although year-over-year variability in the seasonal pattern is substantial, likely due to differences in external forcing. Suspended particulate phosphorus exhibits a seasonal maximum during the spring bloom, despite the absence of a seasonal peak in SRP. However, DOP concentrations are at an annual maximum prior to the winter/spring bloom and decline over the course of the spring bloom while whole community alkaline phosphatase activities are highest. As a result of DOP bioavailability, the growth of particles during the spring bloom occurs in Redfield proportions, though particles exported from the euphotic zone show rapid and significant remineralization of phosphorus within the first 50 m below the euphotic zone. Based upon DOP data from transect cruises in this region, the southward cross gyral flux of DOP is estimated to support ~25% of annual primary production and ~100% of phosphorus export. These estimates are consistent with other research in the subtropical North Atlantic and reinforce the hypothesis that while the subtropics may be phosphorus stressed (a physiological response to low inorganic phosphorus), utilization of the DOP pool allows production and accumulation of microbial biomass at Redfield proportions.This research was supported
by the NSF Biological Oceanography Program through awards
OCE-0453023 (MWL), OCE-0451419 (STD), OCE-0452904
(JWA). We also acknowledge support for the Bermuda Atlantic
Time-series Study provided by the NSF Chemical and Biological
Oceanography Programs through the most recent awards OCE
0326885 and OCE 0752366. CS thanks The Charrock Foundation
and Princeton Environmental Institute for her support
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How to Stage a Coup: and ten other lessons from the world of secret statecraft
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