1,201 research outputs found
The distribution of atomic hydrogen in the Jovian atmosphere
An analysis is presented of the Voyager and IUE lyman alpha spectra of the Jovian equatorial emission in which was derived a zonal asymmetry in the hydrogen column abundance. Using two estimates of the fraction of Lyman alpha which is due to direct excitation by charged particle precipitation from the ionosphere, upper and lower limits were derived to the H column abundance within and without the perturbed region. That the asymmetry in H abundance may be due to localized heating near the homopause with a consequent rise in scale height is shown. The derived exospheric temperature remains fairly constant with longitude. The required additional heat input over the bulge region, 0.02 erg/cm/s, is supplied by an additional flux of magnetospheric electrons due to Jupiter's magnetic anomaly
A Note on the Knossos Mc tablets
The paper discusses the possibility that two of the Linear B records classed as Mc at Knossos date from a different phase (or different phases) in the history of the palace from the remaining records of their type.L'article discuteix la possibilitat que dos dels documents en Lineal B classificats com Mc a Knossos es remuntin a una o diverses fases de la història del palau diferents d'aquella a la qual pertanyen la resta de documents d'aquesta mena
To boldly gulp: standard metabolic rate and boldness have context-dependent influences on risk-taking to breathe air in a catfish
The African sharptooth catfish Clarias gariepinus has bimodal respiration, it has a suprabranchial air-breathing organ alongside substantial gills. We used automated bimodal respirometry to reveal that undisturbed juvenile catfish (N=29) breathed air continuously in normoxia, with a marked diurnal cycle. Air breathing and routine metabolic rate (RMR) increased in darkness when, in the wild, this nocturnal predator forages. Aquatic hypoxia (20% air saturation) greatly increased overall reliance on air breathing. We investigated whether two measures of risk taking to breathe air, namely absolute rates of aerial O2 uptake (ṀO2,air) and the percentage of RMR obtained from air (%ṀO2,air), were influenced by individual standard metabolic rate (SMR) and boldness. In particular, whether any influence varied with resource availability (normoxia versus hypoxia) or relative fear of predation (day versus night). Individual SMR, derived from respirometry, had an overall positive influence on ṀO2,air across all contexts but a positive influence on %ṀO2,air only in hypoxia. Thus, a pervasive effect of SMR on air breathing became most acute in hypoxia, when individuals with higher O2 demand took proportionally more risks. Boldness was estimated as time required to resume air breathing after a fearful stimulus in daylight normoxia (Tres). Although Tres had no overall influence on ṀO2,air or %ṀO2,air, there was a negative relationship between Tres and %ṀO2,air in daylight, in normoxia and hypoxia. There were two Tres response groups, ‘bold’ phenotypes with Tres below 75 min (N=13) which, in daylight, breathed proportionally more air than ‘shy’ phenotypes with Tres above 115 min (N=16). Therefore, individual boldness influenced air breathing when fear of predation was high. Thus, individual energy demand and personality did not have parallel influences on the emergent tendency to take risks to obtain a resource; their influences varied in strength with context
Factors influencing academic success or failure of first-year and senior university students: do education students and lecturers perceive things differently?
South African universities are changing in several very important ways; their entry standards are changing, their programmes are focusing more specifically on the outcomes that learners are required to achieve, and their student populations are becoming more diverse. These changes are occurring in a climate of increased accountability. It is, therefore, important for universities to be concerned about the standards of their academic programmes and about the success rates of students. Together, these factors have produced a range of opinions about what needs to happen in universities if the diverse range of students is to be successful in outcomes-based programmes that maintain high standards. Some educators argue that entry standards are the most important determinants of success at university; others maintain that non-academic factors must also be considered. There is considerable evidence that the views and expectations about success held by lecturers and stud ents are not always consistent. This article presents the results of a recent empirical investigation at the University of Pretoria that attempted to identify the post-enrolment factors that lecturers and students perceived as having important influences on students' success in their university studies. The study investigated the different expectations of first-year students, senior students and lecturers and identified numerous important similarities and inconsistencies. Most notably, there was a high and significant correlation between the rankings the three groups (lecturers, first-year students and senior students) gave to 52 factors linked to successful university study. There was also a high and significant correlation between the rankings of lecturers and senior students on 55 factors suggestive of unsuccessful university study. However, the perceptions of first-year students were not strongly correlated with either lectures or senior students. This suggests that First-year students may have unrealistic expectations about the non-academic factors that could reduce their chances of successful study. The results of the research could be used in three ways. University administrators could provide more supportive learning environments to enhance the chances that students will be successful and lecturers could also use the information to enhance the influences of positive factors on student learning. The influence of negative factors could also be minimised accordingly. Finally students could also be assisted and supported to approach university studies in a way that will increase their chances of success.
South African Journal of Education Vol.23(4) 2003: 254-26
Hydrological hazard assessment for irrigated agriculture in the Irwin focus area
The Midlands groundwater and land assessment project aimed to identify 2000–3000 hectare precincts suitable to develop intensive irrigated horticulture. The primary focus area was at Irwin, where the Department of Water and Environmental Regulation investigated groundwater resources and the Department of Primary Industries and Regional Development undertook a multi-faceted site assessment. This report describes the hydrological hazards assessment for the Irwin focus area.
The Irwin focus area is located on fertile loam and clay flats associated with the Irwin River. In the east, it encompasses the Irwin River valley floor and the western boundary loops to the south of the Irwin River to capture an area of alluvial clays. The Gingin Scarp forms a boundary between the east and west parts of the focus area.
We used groundwater data from resource condition monitoring in the Arrowsmith Hydrozone to assess the hydrological hazards in the Irwin focus area and guide more intensive field investigations. We undertook a shallow drilling program to investigate the profile and to sample and monitor the watertable in the western part of the Irwin focus area. Monitoring bores were established at 13 sites on the alluvial clay flats.
The shallow drilling program was complemented with ground-based electromagnetic surveys. A vehicle-mounted system was developed to record electrical conductivity measurements from Geonics™ EM38 and EM31 instruments.
Historical groundwater level monitoring in the Irwin River valley indicates consistently rising groundwater levels east of the Gingin Scarp in the Arrowsmith Hydrozone. This trend and shallow depth to groundwater poses a significant risk of dryland salinity developing in this landscape. This existing hydrological hazard, rising groundwater and salinity, makes the eastern part of the focus area unsuitable for irrigated horticulture.
West of the Gingin Scarp, the soil profile under the alluvial flats that extend south of the Irwin River is dominated by stiff, moist, grey clay that becomes red-brown or mottled brown and pale grey clay with depth.
While the surface soils are not salt-affected, there is significant salt storage at depth, starting from about 3m to about 7–10m. Since groundwater is not rising in this area the regolith salt storage is not a hazard for dryland agriculture. However, if irrigation water is applied and groundwater rises, it will become a significant hazard.
The hydraulic properties of the alluvial clays could not be closely observed during the investigation because of the absence of recharge due to low rainfall. However, the drill cuttings of heavy, moist clay indicate that there is low hydraulic conductivity or permeability. If the surface soils were to become saline from irrigation, they would likely remain saline because of the limited leachability of the clays
Fish swimming in schools save energy regardless of their spatial position
For animals, being a member of a group provides various advantages, such as reduced vulnerability to predators, increased foraging opportunities and reduced energetic costs of locomotion. In moving groups such as fish schools, there are benefits of group membership for trailing individuals, who can reduce the cost of movement by exploiting the flow patterns generated by the individuals swimming ahead of them. However, whether positions relative to the closest neighbours (e.g. ahead, sided by side or behind) modulate the individual energetic cost of swimming is still unknown. Here, we addressed these questions in grey mullet Liza aurata by measuring tail-beat frequency and amplitude of 15 focal fish, swimming in separate schools, while swimming in isolation and in various positions relative to their closest neighbours, at three speeds. Our results demonstrate that, in a fish school, individuals in any position have reduced costs of swimming, compared to when they swim at the same speed but alone. Although fish swimming behind their neighbours save the most energy, even fish swimming ahead of their nearest neighbour were able to gain a net energetic benefit over swimming in isolation, including those swimming at the front of a school. Interestingly, this energetic saving was greatest at the lowest swimming speed measured in our study. Because any member of a school gains an energetic benefit compared to swimming alone, we suggest that the benefits of membership in moving groups may be more strongly linked to reducing the costs of locomotion than previously appreciated
Project portfolio management: The linchpin in strategy processes
© Cambridge University Press 2017. Introduction Project portfolio management (PPM) is a central component of organizational project management (OPM), especially through its role in both the formulation and the delivery of organizational strategy. Corporate activities are increasingly carried out in the form of projects, in a trend that has been called “projectification” (Midler, 1995). In particular, for the implementation of complex innovations, it is not enough for organizations to focus on the successful management of individual innovation projects; they must also manage a large number of interdependent projects from a portfolio perspective. In today's dynamic environment, organizing by projects has become the rule rather than the exception, and organizations face challenges in managing these large project landscapes (programs and portfolios). The management of project portfolios is closely linked to the implementation of strategies. As strategies are ultimately implemented by projects, PPM – as a link between corporate strategy and projects – plays a central role (Meskendahl, 2010). In most research and practice this role is considered from a top-down perspective: strategies are considered to be a given yardstick for the prioritization and selection of projects and the allocation of resources. From such perspectives, PPM acts as the recipient of strategic goals and requirements that need only to be operationalized. However, the strategic management literature has long recognized the importance of emergent strategy; and that the realized strategy (the strategy that is actually implemented) often strays from the intended strategy (Mintzberg, 1978). Surprisingly, this is hardly considered in existing research models and standards for PPM (PMI, 2013). While there is some empirical evidence to suggest that hierarchical, formal, top-down approaches are not the actual practice of PPM (Christiansen & Varnes, 2009; Jerbrant & Gustavsson, 2013; Martinsuo, 2013), a much broader debate is needed to fully explore the role of PPM in the context of emergent strategies. The goal of this chapter is therefore to explore the role of PPM in the relationship between the formulation and implementation of strategy and consider both the top-down approach as well as the bottom-up strategy emergence. We first discuss emergence in the context of strategy implementation and the role of different phases in the PPM process that affect strategy implementation
Business Case Control in Project Portfolios - An Empirical Investigation of Performance Consequences and Moderating Effects
© 1988-2012 IEEE. Practitioners place strong emphasis on business cases with the expectation that using business cases to inform and drive investment decisions will assist in creating value from those investments. Maximizing the value generated by project investments is a central aim of the project portfolio management, and the business case provides the underlying rationale for the evaluation of the value created in each project. However, research regarding the use of business cases at a project portfolio level is scarce, and there is a little guidance for portfolio managers on when and how to control the business cases. We identify three elements of a business case control at the portfolio level - the initial review, the ongoing monitoring during the project execution, and the postproject tracking until the business case is realized - and investigate the relationship between business case control and project portfolio success. Furthermore, we analyze enablers and contingencies for the application of the business case control. Based on a cross-industry sample of 183 firms, we find that the business case control is positively related to the project portfolio success. Accountability for business case realization and corresponding incentive systems increase this positive effect. Finally, we show that the portfolio complexity also positively moderates the relationship
The Role of Innovation Portfolio Management in the Nexus between Deliberate and Emergent Innovation Strategies
Planning and implementing innovation strategies are typically considered to be top-down processes and innovation portfolio management plays a decisive role in this context by aligning the project portfolio to the firm’s strategy. However, in strategic management research it is well accepted that strategies are not solely deliberate but can also be emergent. Thus, between top-down innovation strategy formulation and its implementation, responding dialectic elements are required to sense emerging strategic impetuses and cope with changing environmental conditions. This paper addresses the role of portfolio management in the nexus between strategy formulation and implementation. Using a sample of 182 medium and large firms with two informants, we show that portfolio management not only fosters the implementation of intended innovation strategies through vertical integration but also discloses strategic opportunities by unveiling emerging patterns. The findings show that portfolio management contributes to innovation portfolio success by supporting both the implementation of deliberate and emergent strategies through vertical integration and strategic disclosure. The effects are complementary in that both activities increase the positive effects of the other. Furthermore we find that strategic control (i.e. premise control, implementation control, and strategic surveillance) on a portfolio level indirectly contributes to success mediated by vertical integration and strategic disclosure. Finally, we show that the influence of vertical integration on innovation portfolio success is reduced under high environmental turbulence
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