Research summary: A substantial and burgeoning body of research has described the influence of platform-mediated networks in a wide variety of settings, whereby users and complementors desire ...compatibility on a common platform. In this review, we outline extant views of these dynamics from the industrial organization (IO) economics, technology management, and strategic management perspectives. Using this review as a foundation, we propose a future research agenda in this domain that focuses the on the relative influence of network effects and platform quality in competitive outcomes, drivers of indirect network effects, the nature and attributes of complementors, and leveraging complementor dynamics for competitive advantage. Managerial summary: In many industries, such as social networks and video games, consumers place greater value on products with a large network of other users and a large variety of complementary products. Such "network effects" offer lucrative opportunities for firms that can leverage these dynamics to create dominant technology platforms. This article reviews current perspectives on network effects and the emergence of platforms, and offers several areas of future consideration for optimal strategies in these settings.
Protecting the world's freshwater resources requires diagnosing threats over a broad range of scales, from global to local. Here we present the first worldwide synthesis to jointly consider human and ...biodiversity perspectives on water security using a spatial framework that quantifies multiple stressors and accounts for downstream impacts. We find that nearly 80% of the world's population is exposed to high levels of threat to water security. Massive investment in water technology enables rich nations to offset high stressor levels without remedying their underlying causes, whereas less wealthy nations remain vulnerable. A similar lack of precautionary investment jeopardizes biodiversity, with habitats associated with 65% of continental discharge classified as moderately to highly threatened. The cumulative threat framework offers a tool for prioritizing policy and management responses to this crisis, and underscores the necessity of limiting threats at their source instead of through costly remediation of symptoms in order to assure global water security for both humans and freshwater biodiversity.
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Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Highlights ► Literature review and pooled data analysis on infant pertussis infection sources. ► Parents were an important source of pertussis infection in very young infants. ► Grandparents were ...seldom implicated in infant pertussis infection. ► Siblings play a role as pertussis a source, but data is heterogeneous. ► Parents should be the focus of post-partum pertussis immunisation.
Abstract Introduction In Australia, post-marketing surveillance for intussusception following vaccination commenced with funding of RotaTeq ® and Rotarix ® vaccines under the National Immunization ...Program (NIP) in July 2007. Methods Two active surveillance mechanisms (hospital-based case ascertainment and monthly reports from paediatricians) identified intussusception cases between 1st July 2007 and 31st December 2008 in four states. Linkage to vaccination records identified cases occurring within 1–7 and 1–21 days of rotavirus vaccination. Expected cases within the post-vaccination windows were calculated by applying rates of intussusception from national hospitalisation data over 6 years (mid-2000 to mid-2006), by age and state, to numbers vaccinated (by dose) according to the Australian Childhood Immunization Register. Results Combining exposure windows associated with all doses of rotavirus vaccine from 1 to 9 months of age, there was no evidence of an increased risk of intussusception following vaccination for either vaccine. However, in infants 1 to <3 months of age, there was suggestive evidence of excess intussusception cases 1–7 and 1–21 days following dose 1 (1–7 days: RotaTeq ® relative risk (RR) = 5.3, 95% confidence interval CI 1.1,15.4; Rotarix ® RR 3.5, 95% CI 0.7,10.1; 1–21 days: RotaTeq ® RR 3.5, 95% CI 1.3, 7.6; Rotarix ® RR 1.5, 95% CI 0.4, 3.9). There was no evidence that clinical outcome of intussusception occurring within 21 days of rotavirus vaccination differed from that in cases occurring later post-vaccination. Conclusion Although we found no overall increase in intussusception following receipt of rotavirus vaccine, there was some evidence of an elevated risk following the first dose of both vaccines. Larger population-based studies using linked databases are required to provide more definitive evidence.
Quantitative information regarding the endmember composition of the gas and oil that flowed from the Macondo well during the Deepwater Horizon oil spill is essential for determining the oil flow ...rate, total oil volume released, and trajectories and fates of hydrocarbon components in the marine environment. Using isobaric gas-tight samplers, we collected discrete samples directly above the Macondo well on June 21, 2010, and analyzed the gas and oil. We found that the fluids flowing from the Macondo well had a gas-to-oil ratio of 1,600 standard cubic feet per petroleum barrel. Based on the measured endmember gas-to-oil ratio and the Federally estimated net liquid oil release of 4.1 million barrels, the total amount of C ₁-C ₅ hydrocarbons released to the water column was 1.7 10 ¹¹ g. The endmember gas and oil compositions then enabled us to study the fractionation of petroleum hydrocarbons in discrete water samples collected in June 2010 within a southwest trending hydrocarbon-enriched plume of neutrally buoyant water at a water depth of 1,100 m. The most abundant petroleum hydrocarbons larger than C ₁-C ₅ were benzene, toluene, ethylbenzene, and total xylenes at concentrations up to 78 μg L ⁻¹. Comparison of the endmember gas and oil composition with the composition of water column samples showed that the plume was preferentially enriched with water-soluble components, indicating that aqueous dissolution played a major role in plume formation, whereas the fates of relatively insoluble petroleum components were initially controlled by other processes.
The Deepwater Horizon blowout is the largest offshore oil spill in history. We present results from a subsurface hydrocarbon survey using an autonomous underwater vehicle and a ship-cabled sampler. ...Our findings indicate the presence of a continuous plume of oil, more than 35 kilometers in length, at approximately 1100 meters depth that persisted for months without substantial biodegradation. Samples collected from within the plume reveal monoaromatic petroleum hydrocarbon concentrations in excess of 50 micrograms per liter. These data indicate that monoaromatic input to this plume was at least 5500 kilograms per day, which is more than double the total source rate of all natural seeps of the monoaromatic petroleum hydrocarbons in the northern Gulf of Mexico. Dissolved oxygen concentrations suggest that microbial respiration rates within the plume were not appreciably more than 1 micromolar oxygen per day.
Basin-scale planning is needed to minimize impacts in mega-diverse rivers
The world's most biodiverse river basins—the Amazon, Congo, and Mekong—are experiencing an unprecedented boom in construction ...of hydropower dams. These projects address important energy needs, but advocates often overestimate economic benefits and underestimate far-reaching effects on biodiversity and critically important fisheries. Powerful new analytical tools and high-resolution environmental data can clarify trade-offs between engineering and environmental goals and can enable governments and funding institutions to compare alternative sites for dam building. Current site-specific assessment protocols largely ignore cumulative impacts on hydrology and ecosystem services as ever more dams are constructed within a watershed (
1
). To achieve true sustainability, assessments of new projects must go beyond local impacts by accounting for synergies with existing dams, as well as land cover changes and likely climatic shifts (
2
,
3
). We call for more sophisticated and holistic hydropower planning, including validation of technologies intended to mitigate environmental impacts. Should anything less be required when tampering with the world's great river ecosystems?
Maternal influenza and pertussis immunisation is crucial for protecting mothers during pregnancy and their babies in the first weeks of life against severe disease. We examined geospatial variation ...in maternal immunisation coverage among pregnant women in Aotearoa New Zealand and its health equity implications.
We constructed a retrospective cohort including all pregnant women who delivered between 01 January 2013 and 31 December 2020 using administrative health datasets. Our outcomes were receipt of influenza or pertussis vaccine in any one of three relevant national databases (e.g. National Immunisation Register, Proclaims, or Pharmaceutical collection) during the eligible pregnancy.
Data from our retrospective cohort study show significant regional variation in maternal immunisation coverage for both influenza and pertussis from 2013 to 2020. Maximal coverage was around 50% in the best performing regions, which means that half of the women who were pregnant (183,737 women) were not protected. In addition, we found significant spatio-temporal variation and clustering of immunisation coverage. Our findings are interactively available to explore here: https://geohealthlab.shinyapps.io/hapumama/
Our study is one of the first to examine spatial variation in maternal vaccination coverage in pregnant women at a national level over space and time. This provides powerful tools to measure the impact of interventions to improve coverage at national and regional levels, with specific reference to inequities between ethnic groups, likely applicable to similar settings internationally.
•Maternal influenza and pertussis vaccine coverage is suboptimal.•Maximum coverage was around 50% in the best performing regions.•There was significant spatiotemporal variation and clustering in coverage.•Our data can be used to inform nationwide policy.
This article reviews extant theoretical perspectives and empirical literature at the nexus of network effects and strategy. Building on these insights, it offers a research framework that focuses on ...three primary avenues: the strategic drivers of network intensity, approaches to assess variations in network intensity, and effective strategies for leveraging network intensity. In doing so, the study widens the perspective of the role of strategy in network industries and offers directions for future research.
Abstract Advanced age has been associated with a wide range of defects in both the innate and adaptive immune systems including diminished specific antibody responses that increase the risk of ...invasive pneumococcal disease (IPD) and limit the effectiveness of vaccines. However, the elderly are a heterogeneous group and measures of overall frailty may be a better indicator of disease susceptibility (or vaccine response) than chronological age alone. Aim To evaluate the immunogenicity of the 7-valent conjugated pneumococcal vaccine (PCV7) versus 23-valent polysaccharide vaccine (23vPPV) and compare the immune response to four serotypes (4, 6B, 18C and 19F), with respect to age or frailty in an elderly population of previously unvaccinated hospitalized patients. Method 241 patients aged 60 years and over, recruited between 16 May 2005 and 20 February 2006, were randomised to 23PPV or PCV7 vaccine. We measured Frailty Index (FI), Barthel index and the MiniMental State. Serotype-specific IgG was measured by ELISA at base line and 6 months after vaccination. Antibody responses were defined by the ratio of post-vaccination to pre-vaccination IgG antibody concentration (poor < 2-fold increase, acceptable ≥ 2.0 to 3.99-fold and strong ≥ 4.0-fold increase). Results Pre-immunization IgG was generally low and did not differ significantly by age or frailty. Post-immunization, IgG increased to all four serotypes; acceptable or strong response ranged between 29% for (6B) and 57% for (18C). There was no significant difference between the two vaccine types (23PPV versus PCV7). At 6 months post-vaccination, the highest geometric mean IgG concentrations (GMCs) were seen for serotype 19F and the lowest for serotype 4. Although there was some variation by serotype, responses after vaccination were lowest in the most frail or aged subjects. Conclusions Pneumococcal vaccines are perceived to offer low protection in the frail elderly, but our study showed that the proportion of this vulnerable population with acceptable responses is encouraging. Frailty, as measured by the Frailty Index, appears to be a better predictor of immune response to pneumococcal vaccines than age alone.
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