Controlled Ascent From the Surface of an Asteroid

The National Aeronautics and Space Administration (NASA) is currently investigating a conceptual robotic mission to collect a small boulder up to 4 m in diameter resting on the surface of a large Near Earth Asteroid (NEA). Because most NEAs are not well characterized, a great range of uncertainties in boulder mass properties and NEA surface characteristics must be considered in the design of this mission. These uncertainties are especially significant when the spacecraft ascends with the boulder in tow. The most important requirement during ascent is to keep the spacecraft in an upright posture to maintain healthy ground clearances for the two large solar arrays. This paper focuses on the initial stage (the first 50 m) of ascent from the surface. Specifically, it presents a sensitivity study of the solar array ground clearance, control authority, and accelerations at the array tips in the presence of a variety of uncertainties including various boulder sizes, densities, shapes and orientations, locations of the true center of mass, and push-off force distributions. Results are presented, and appropriate operations are recommended in the event some of the off-nominal cases occur

Understanding employee resourcing in construction organizations

In recent years the literature on employee resourcing has consistently advocated the importance of adopting a holistic, strategic approach to employee deployment decision making rather than adopting a reactive needs-based approach. This is particularly problematic in construction where the multi-project environment leads to constantly changing resource requirements and to changing demands over a project's life cycle. This can lead to inappropriate decisions, which fail to meet the longer-term needs of both construction organizations and their employees. A structured and comprehensive understanding of the current project team deployment practices within large construction organizations was developed. Project deployment practices were examined within seven case study contracting firms. The emergent themes that shaped the decision-making processes were grouped into five broad clusters comprising human resource planning, performance/career management, team deployment, employee involvement and training and development. The research confirms that a reactive and ad hoc approach to the function prevails within the firms investigated. This suggests a weak relationship between the deployment process and human resource planning, team deployment, performance management, employee involvement and training and development activities. It is suggested that strategic HR-business partnering could engender more transparent and productive relationships in this crucial area

Macrofossils and pollen representing forests of the pre-Taupo volcanic eruption (c. 1850 yr BP) era at Pureora and Benneydale, central North Island, New Zealand.

Micro- and macrofossil data from the remains of forests overwhelmed and buried at Pureora and Benneydale during the Taupo eruption (c. 1850 conventional radiocarbon yr BP) were compared. Classification of relative abundance data separated the techniques, rather than the locations, because the two primary clusters comprised pollen and litter/wood. This indicates that the pollen:litter/wood within-site comparisons (Pureora and Benneydale are 20 km apart) are not reliable. Plant macrofossils represented mainly local vegetation, while pollen assemblages represented a combination of local and regional vegetation. However, using ranked abundance and presence/absence data, both macrofossils and pollen at Pureora and Benneydale indicated conifer/broadleaved forest, of similar forest type and species composition at each site. This suggests that the forests destroyed by the eruption were typical of mid-altitude west Taupo forests, and that either data set (pollen or macrofossils) would have been adequate for regional forest interpretation. The representation of c. 1850 yr BP pollen from the known buried forest taxa was generally consistent with trends determined by modern comparisons between pollen and their source vegetation, but with a few exceptions. A pollen profile from between the Mamaku Tephra (c. 7250 yr BP) and the Taupo Ignimbrite indicated that the Benneydale forest had been markedly different in species dominance compared with the forest that was destroyed during the Taupo eruption. These differences probably reflect changes in drainage, and improvements in climate and/or soil fertility over the middle Holocene

Vegetation and peat characteristics of restiad bogs on Chatham Island (Rekohu), New Zealand

Restiad bogs dominated by Sporadanthus traversii on Chatham Island, New Zealand, were sampled to correlate vegetation patterns and peat properties, and to compare with restiad systems dominated by Sporadanthus ferrugineus and Empodisma minus in the Waikato region, North Island, New Zealand. Classification and ordination resulted in five groups that reflected a disturbance gradient. The largest S. traversii group, which comprised plots from central, relatively intact bogs, had the lowest levels of total nitrogen (mean 1.20 mg cm-3), total phosphorus (mean 0.057 mg cm-3), total potassium (mean 0.083 mg cm-3), and available phosphorus (mean 18.6 μg cm-3). Modification by drainage, stock, and fires resulted in a decline of S. traversii and an increase of Gleichenia dicarpa fern cover, together with elevated peat nutrient levels and higher bulk density. Compared with peat dominated by Sporadanthus ferrugineus or Empodisma minus in relatively unmodified Waikato restiad bogs, Chatham Island peat under S. traversii has significantly higher total potassium, total nitrogen, available phosphorus, bulk density, and von Post decomposition indices, and significantly lower pH. Sporadanthus traversii and Empodisma minus have similar ecological roles in restiad bog development, occupying a relatively wide nutrient range, and regenerating readily from seed after fire. Despite differences in root morphology, S. traversii and E. minus are the major peat formers in raised restiad bogs on Chatham Island and in Waikato, respectively, and could be regarded as ecological equivalents

Manageable creativity

This article notes a perception in mainstream management theory and practice that creativity has shifted from being disruptive or destructive to 'manageable'. This concept of manageable creativity in business is reflected in a similar rhetoric in cultural policy, especially towards the creative industries. The article argues that the idea of 'manageable creativity' can be traced back to a 'heroic' and a 'structural' model of creativity. It is argued that the 'heroic' model of creativity is being subsumed within a 'structural' model which emphasises the systems and infrastructure around individual creativity rather than focusing on raw talent and pure content. Yet this structured approach carries problems of its own, in particular a tendency to overlook the unpredictability of creative processes, people and products. Ironically, it may be that some confusion in our policies towards creativity is inevitable, reflecting the paradoxes and transitions which characterise the creative process

Genetic variants in glutamate, Aβ and tau related pathways determine polygenic risk for Alzheimer's disease

Synapse loss is an early event in late-onset Alzheimer's disease (LOAD). In this study we have assessed the capacity of a polygenic risk score (PRS) restricted to synapse-encoding loci to predict LOAD. We used summary statistics from the IGAP genome-wide association meta-analysis of 74,046 subjects for model construction and tested the "Synaptic PRS" in two independent datasets of controls and pathologically-confirmed LOAD. The mean Synaptic PRS was 2.3-fold higher in LOAD compared to controls (

GlbN (cyanoglobin) is a peripheral membrane protein that is restricted to certain Nostoc spp.

The glbN gene of Nostoc commune UTEX 584 is juxtaposed to nifU and nifH, and it encodes a 12-kDa monomeric hemoglobin that binds oxygen with high affinity. In N. commune UTEX 584, maximum accumulation of GlbN occurred in both the heterocysts and vegetative cells of nitrogen-fixing cultures when the rate of oxygen evolution was repressed to less than 25 micromol of O2 mg of chlorophyll a(-1) h(-1). Accumulation of GlbN coincided with maximum synthesis of NifH and ferredoxin NADP+ oxidoreductase (PetH or FNR). A total of 41 strains of cyanobacteria, including 40 nitrogen fixers and representing 16 genera within all five sections of the cyanobacteria were screened for the presence of glbN or GlbN. glbN was present in five Nostoc strains in a single copy. Genomic DNAs from 11 other Nostoc and Anabaena strains, including Anabaena sp. strain PCC 7120, provided no hybridization signals with a glbN probe. A constitutively expressed, 18-kDa protein which cross-reacted strongly with GlbN antibodies was detected in four Anabaena and Nostoc strains and in Trichodesmium thiebautii. The nifU-nifH intergenic region of Nostoc sp. strain MUN 8820 was sequenced (1,229 bp) and was approximately 95% identical to the equivalent region in N. commune UTEX 584. Each strand of the DNA from the nifU-nifH intergenic regions of both strains has the potential to fold into secondary structures in which more than 50% of the bases are internally paired. Mobility shift assays confirmed that NtcA (BifA) bound a site in the nifU-glbN intergenic region of N. commune UTEX 584 approximately 100 bases upstream from the translation initiation site of glbN. This site showed extensive sequence similarity with the promoter region of glnA from Synechococcus sp. strain PCC 7942. In vivo, GlbN had a specific and prominent subcellular location around the periphery of the cytosolic face of the cell membrane, and the protein was found solely in the soluble fraction of cell extracts. Our hypothesis is that GlbN scavenges oxygen for and is a component of a membrane-associated microaerobically induced terminal cytochrome oxidase

A Qualitative Exploration of Factors Affecting Group Cohesion and Team Play in Multiplayer Online Battle Arenas (MOBAs)

Previous research examining the social psychology of video-gaming has tended to focus on Massively Multiplayer Online Role Playing Game (MMORPG) environments, such as World of Warcraft. Although many online group processes have been examined using this game, this genre does not enforce cooperative play and studies tend to be based on very large groups. Newer genres are being developed and played which have so far not been studied. The genre known as Multiplayer Online Battle Arenas (MOBAs) are attracting large numbers of players and success depends on effective team playing within smaller groups. The study reported here explores team play within MOBAs. Due to the lack of literature examining this genre, Corbin and Strauss’ (2008) Grounded Theory was used to analyse participants’ subjective experiences of playing MOBAs to create a conceptual model. A focus group pilot study informed the development of questions and then semi-structured interviews took place with twelve participants; 1 female and 11 male students aged between 18-21 years. Participants were required to have recent and frequent MOBA exposure, but with different preferences regarding roles and experience. Data was analysed using open, axial and selective coding and the resulting model depicts a scale, as optimal team performance was linked to a balance between factors. The core category “Communication” was heavily influenced by the relationship between teammates (friends or strangers). The balance of “Communication” affected the balance of the final three categories: “Team Composition”, “Psychological State” and “Level of Play”. The conceptual model is critically linked with traditional group processes, such as Belbin’s (1993) team roles, Tuckman’s (1965) model of group development and the perceptions and behaviour during the state of deindividuation (Taylor & MacDonald, 2002). The model has real-world application in both social and professional virtual environments, whilst contributing more broadly to research in Cyberpsychology and Social Psychology. Further research is suggested which will test predictions based on a predictive model