807 research outputs found
Domestic Rivalry and Export Performance: Theory and Evidence from International Airline Markets
The much-studied relationship between domestic rivalry and export performance consists of those supporting a national-champion rationale, and those supporting a rivalry rationale. While the empirical literature generally supports the positive effects of domestic rivalry, the national-champion rationale actually rests on firmer theoretical ground. We address this inconsistency by providing a theoretical framework that illustrates three paths via which domestic rivalry translates into enhanced international exports. Furthermore, empirical tests on the world airline industry elicit the existence of one particular path - an enhanced firm performance effect - that connects domestic rivalry with improved international exports
Together, yet still not equal? Sex integration in equestrian sport
Sex segregation is a core organising principle of most modern sports and is a key element in the marginalisation and subordination of girls and women in sport and beyond. In this article I explore the only Olympic-level sport which is not organised around sex segregation – equestrian sport – in order to consider the implications of sex integration for female participants. I draw on a study conducted on elite riders that found that although sex integration in equestrian sport does not lead to female participants being excluded from high-level competition, men continue to perform disproportionately well. This suggests that although sex integration may be an important step towards breaking down gender hierarchies in sport, without accompanying wider changes in gender norms and expectations, sex integration alone will not be enough to achieve greater gender equality in equestrian sport
The dimensions of software engineering success
Software engineering research and practice are hampered by the lack of a well-understood, top-level dependent variable. Recent initiatives on General Theory of Software Engineering suggest a multifaceted variable – Software Engineering Success. However, its exact dimensions are unknown. This paper investigates the dimensions (not causes) of software engineering success. An interdisciplinary sample of 191 design professionals (68 in the software industry) were interviewed concerning their perceptions of success. Non-software designers (e.g. architects) were included to increase the breadth of ideas and facilitate comparative analysis. Transcripts were subjected to supervised, semi-automated semantic content analysis, including a software developer vs. other professionals comparison. Findings suggest that participants view their work as time-constrained projects with explicit clients and other stakeholders. Success depends on stakeholder impacts – financial, social, physical and emotional – and is understood through feedback. Concern with meeting explicit requirements is peculiar to software engineering and design is not equated with aesthetics in many other fields. Software engineering success is a complex multifaceted variable, which cannot sufficiently be explained by traditional dimensions including user satisfaction, profitability or meeting requirements, budgets and schedules. A proto-theory of success is proposed, which models success as the net impact on a particular stakeholder at a particular time. Stakeholder impacts are driven by project efficiency, artifact quality and market performance. Success is not additive, e.g., ‘low’ success for clients does not average with ‘high’ success for developers to make ‘moderate’ success overall; rather, a project may be simultaneously successful and unsuccessful from different perspectives
Ventricular diastolic filling characteristics in stage-24 chick embryos after extra-embryonic venous obstruction
Alteration of extra-embryonic venous blood flow in stage-17 chick embryos
results in well-defined cardiovascular malformations. We hypothesize that
the decreased dorsal aortic blood volume flow observed after venous
obstruction results in altered ventricular diastolic function in stage-24
chick embryos. A microclip was placed at the right lateral vitelline vein
in a stage-17 (52-64 h of incubation) chick embryo. At stage 24 (4.5 days
of incubation), we measured simultaneously dorsal aortic and
atrioventricular blood flow velocities with a 20-MHz pulsed-Doppler
velocity meter. The fraction of passive and active filling was integrated
and multiplied by dorsal aortic blood flow to obtain the relative passive
and active ventricular filling volumes. Data were summarized as means +/-
S.E.M. and analyzed by t-test. At similar cycle lengths ranging from 557
ms to 635 ms (P>0.60), dorsal aortic blood flow and stroke volume measured
in the dorsal aorta were similar in stage-24 clipped and normal embryos.
Passive filling volume (0.07+/-0.01 mm(3)) was decreased, and active
filling volume (0.40+/-0.02 mm(3)) was increased in the clipped embryo
when compared with the normal embryo (0.15+/-0.01 mm(3), 0.30+/-0.01
mm(3), respectively) (P<0.003). In the clipped embryos, the passive/active
ratio was decreased compared with that in normal embryos (P<0.001).
Ventricular filling components changed after partially obstructing the
extra-embryonic venous circulation. These results suggest that material
properties of the embryonic ventricle are modified after temporarily
reduced hemodynamic load
The future excess fraction of cancer due to lifestyle factors in Australia
Background: Many cancers are caused by exposure to lifestyle, environmental, and occupational factors. Earlier studies have estimated the number of cancers occurring in a single year which are attributable to past exposures to these factors. However, there is now increasing appreciation that estimates of the future burden of cancer may be more useful for policy and prevention. We aimed to calculate the future number of cancers expected to arise as a result of exposure to 23 modifiable risk factors. Methods: We used the future excess fraction (FEF) method to estimate the lifetime burden of cancer (2016–2098) among Australian adults who were exposed to modifiable lifestyle, environmental, and occupational risk factors in 2016. Calculations were conducted for 26 cancer sites and 78 cancer-risk factor pairings. Results: The cohort of 18.8 million adult Australians in 2016 will develop an estimated 7.6 million cancers during their lifetime, of which 1.8 million (24%) will be attributable to exposure to modifiable risk factors. Cancer sites with the highest number of future attributable cancers were colon and rectum (n = 717,700), lung (n = 380,400), and liver (n = 103,200). The highest number of future cancers will be attributable to exposure to tobacco smoke (n = 583,500), followed by overweight/obesity (n = 333,100) and alcohol consumption (n = 249,700). Conclusion: A significant proportion of future cancers will result from recent levels of exposure to modifiable risk factors. Our results provide direct, pertinent information to help determine where preventive measures could best be targeted
The use of toxicokinetics and exposure studies to show that carprofen in cattle tissue could lead to secondary toxicity and death in wild vultures
Veterinary medicines can be extremely damaging to the environment, as seen with the catastrophic declines in Gyps vulture in South Asia due to their secondary exposure to diclofenac in their primary food source. Not surprisingly, concern has been raised over other similar drugs. In this study, we evaluate the toxicity of carprofen to the Gyps vulture clade through plasma pharmacokinetics evaluations in Bos taurus cattle (their food source) and Gyps africanus (a validated model species); tissue residues in cattle; and the effect of carprofen as a secondary toxicant as both tissue-bound residue or pure drug at levels expected in cattle tissues. Carprofen residues were highest in cattle kidney (7.72 ± 2.38 mg/kg) and injection site muscle (289.05 ± 98.96 mg/kg of dimension of 5 × 5 × 5 cm). Vultures exposed to carprofen as residues in the kidney tissue or pure drug equivalents showed no toxic signs. When exposed to average injection site concentrations (64 mg/kg) one of two birds died with evidence of severe renal and liver damage. Toxicokinetic analysis revealed a prolonged drug half-life of 37.75 h in the dead bird as opposed to 13.99 ± 5.61 h from healthy birds dosed intravenously at 5 mg/kg. While carprofen may generally be harmless to Gyps vultures, its high levels at the injection site in treated cattle can result in lethal exposure in foraging vultures, due to relative small area of tissue it is found therein. We thus suggest that carprofen not be used in domesticated ungulates in areas where carcasses are accessible or provided to vultures at supplementary feeding sites.The Royal Society for the Protection of Birds and the Chester Zoo.http://www.elsevier.com/locate/chemosphere2019-01-01hj2018Paraclinical Science
Upper critical field for underdoped high-T_c superconductors. Pseudogap and stripe--phase
We investigate the upper critical field in a stripe--phase and in the
presence of a phenomenological pseudogap. Our results indicate that the
formation of stripes affects the Landau orbits and results in an enhancement of
. On the other hand, phenomenologically introduced pseudogap leads to a
reduction of the upper critical field. This effect is of particular importance
when the magnitude of the gap is of the order of the superconducting transition
temperature. We have found that a suppression of the upper critical field takes
place also for the gap that originates from the charge--density waves.Comment: 7 pages, 5 figure
Vortex structure in d-density wave scenario of pseudogap
We investigate the vortex structure assuming the d-density wave scenario of
the pseudogap. We discuss the profiles of the order parameters in the vicinity
of the vortex, effective vortex charge and the local density of states. We find
a pronounced modification of these quantities when compared to a purely
superconducting case. Results have been obtained for a clean system as well as
in the presence of a nonmagnetic impurity. We show that the competition between
superconductivity and the density wave may explain some experimental data
recently obtained for high-temperature superconductors. In particular, we show
that the d-density wave scenario explains the asymmetry of the gap observed in
the vicinity of the vortex core.Comment: 8 pages, 10 figure
Structural, Electronic, and Magnetic Properties of MnO
We calculate the structural, electronic, and magnetic properties of MnO from
first principles, using the full-potential linearized augmented planewave
method, with both local-density and generalized-gradient approximations to
exchange and correlation. We find the ground state to be of rhombohedrally
distorted B1 structure with compression along the [111] direction,
antiferromagnetic with type-II ordering, and insulating, consistent with
experiment. We show that the distortion can be understood in terms of a
Heisenberg model with distance dependent nearest-neighbor and
next-nearest-neighbor couplings determined from first principles. Finally, we
show that magnetic ordering can induce significant charge anisotropy, and give
predictions for electric field gradients in the ground-state rhombohedrally
distorted structure.Comment: Submitted to Physical Review B. Replaced: regenerated figures to
resolve font problems in automatically generated pd
Carrier relaxation, pseudogap, and superconducting gap in high-Tc cuprates: A Raman scattering study
We describe results of electronic Raman-scattering experiments in differently
doped single crystals of Y-123 and Bi-2212. The comparison of AF insulating and
metallic samples suggests that at least the low-energy part of the spectra
originates predominantly from excitations of free carriers. We therefore
propose an analysis of the data in terms of a memory function approach.
Dynamical scattering rates and mass-enhancement factors for the carriers are
obtained. In B2g symmetry the Raman data compare well to the results obtained
from ordinary and optical transport. For underdoped materials the dc scattering
rates in B1g symmetry become temperature independent and considerably larger
than in B2g symmetry. This increasing anisotropy is accompanied by a loss of
spectral weight in B2g symmetry in the range between the superconducting
transition at Tc and a characteristic temperature T* of order room temperature
which compares well with the pseudogap temperature found in other experiments.
The energy range affected by the pseudogap is doping and temperature
independent. The integrated spectral loss is approximately 25% in underdoped
samples and becomes much weaker towards higher carrier concentration. In
underdoped samples, superconductivity related features in the spectra can be
observed only in B2g symmetry. The peak frequencies scale with Tc. We do not
find a direct relation between the pseudogap and the superconducting gap.Comment: RevTeX, 21 pages, 24 gif figures. For PostScript with embedded eps
figures, see http://www.wmi.badw-muenchen.de/~opel/k2.htm
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