1,089 research outputs found
Quantum Secrecy in Thermal States
We propose to perform quantum key distribution using quantum correlations
occurring within thermal states produced by low power sources such as LED's.
These correlations are exploited through the Hanbury Brown and Twiss effect. We
build an optical central broadcast protocol using a superluminescent diode
which allows switching between laser and thermal regimes, enabling us to
provide experimental key rates in both regimes. We provide a theoretical
analysis and show that quantum secrecy is possible, even in high noise
situations.Comment: This version includes revisions prompted by referees comments, and
some other small editorial comment
Quantifying the Importance of MSP1-19 as a Target of Growth-Inhibitory and Protective Antibodies against Plasmodium falciparum in Humans
BACKGROUND: Antibodies targeting blood stage antigens are important in protection against malaria, but the key targets and mechanisms of immunity are not well understood. Merozoite surface protein 1 (MSP1) is an abundant and essential protein. The C-terminal 19 kDa region (MSP1-19) is regarded as a promising vaccine candidate and may also be an important target of immunity. METHODOLOGY/FINDINGS: Growth inhibitory antibodies against asexual-stage parasites and IgG to recombinant MSP1-19 were measured in plasma samples from a longitudinal cohort of 206 children in Papua New Guinea. Differential inhibition by samples of mutant P. falciparum lines that expressed either the P. falciparum or P. chabaudi form of MSP1-19 were used to quantify MSP1-19 specific growth-inhibitory antibodies. The great majority of children had detectable IgG to MSP1-19, and high levels of IgG were significantly associated with a reduced risk of symptomatic P. falciparum malaria during the 6-month follow-up period. However, there was little evidence of PfMSP1-19 specific growth inhibition by plasma samples from children. Similar results were found when testing non-dialysed or dialysed plasma, or purified antibodies, or when measuring growth inhibition in flow cytometry or microscopy-based assays. Rabbit antisera generated by immunization with recombinant MSP1-19 demonstrated strong MSP1-19 specific growth-inhibitory activity, which appeared to be due to much higher antibody levels than human samples; antibody avidity was similar between rabbit antisera and human plasma. CONCLUSIONS/SIGNIFICANCE: These data suggest that MSP1-19 is not a major target of growth inhibitory antibodies and that the protective effects of antibodies to MSP1-19 are not due to growth inhibitory activity, but may instead be mediated by other mechanisms. Alternatively, antibodies to MSP1-19 may act as a marker of protective immunity
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Analyzing procedural equity in government-led community-based forest management
Participatory approaches to forest management have been promoted as a means of returning rights historically removed, and as a way of managing natural resources sustainably, fairly, and to improve livelihoods in communities. Top-down models of community-based forest management take the perspective that if people feel ownership over, have a voice in decisions about, and can benefit from surrounding ecosystems, then they will be motivated to maintain and protect them. However, even participatory approaches, such as community-based forest management, may not always result in clear positive outcomes for involvement in decision making and forest conservation. We examine whether an Indonesian government initiative for community-based forest management was positively associated with community members' participation in local decision making and support for conservation and sustainable management of forest resources, in the context of state-owned lands. We used household questionnaire data to compare villages with and without a community forest, and community forests over time in a case study region of West Kalimantan. Analyzing forest visitations, conservation support, and indicators of procedural equity, we found no consistent association between having a community forest and higher levels of participation in decision making or household support for forest conservation. However, well-being indicators were positively associated with more active participation. The level of support for forest conservation was also positively related to households' leadership in village institutions and higher levels of well-being, particularly subjective well-being, land tenure, and material wealth. These social-demographic factors are important considerations when designing and implementing community-based forest management, which strives for fair and just decision-making processes along with forest conservation. The findings highlight how existing socioeconomic contexts factor into local institutions, and that accounting for these in program design and implementation may help address existing social inequalities that influence achieving joint social and ecological objectives
Low knowledge of newborn danger signs among pregnant women in Papua New Guinea and implications for health seeking behaviour in early infancy – findings from a longitudinal study
Background: Globally, 2.5 million babies die in the first 28 days of life each year with most of these deaths occurring in low- and middle-income countries. Early recognition of newborn danger signs is important in prompting timely care seeking behaviour. Little is known about women’s knowledge of newborn danger signs in Papua New Guinea. This study aims to assess this knowledge gap among a cohort of women in East New Britain Province.
Methods: This study assessed knowledge of newborn danger signs (as defined by the World Health Organization) at three time points from a prospective cohort study of women in East New Britain Province, factors associated with knowledge of danger signs after childbirth were assessed using logistic regression. This study includes quantitative and qualitative interview data from 699 pregnant women enrolled at their first antenatal clinic visit, followed up after childbirth (n = 638) and again at one-month post-partum (n = 599).
Results: Knowledge of newborn danger signs was very low. Among the 638 women, only 9.4% knew three newborn danger signs after childbirth and only one knew all four essential danger signs defined by Johns Hopkins University ‘Birth Preparedness and Complication Readiness’ Index. Higher knowledge scores were associated with higher gravidity, income level, partner involvement in antenatal care, and education.
Conclusion: Low levels of knowledge of newborn danger signs among pregnant women are a potential obstacle to timely care-seeking in rural Papua New Guinea. Antenatal and postnatal education, and policies that support enhanced education and decision-making powers for women and their families, are urgently needed
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Impact of palm oil sustainability certification on village well-being and poverty in Indonesia
The Roundtable on Sustainable Palm Oil (RSPO) has emerged as the leading sustainability certification system to tackle socio-environmental issues associated with the oil palm industry. To date, the effectiveness of RSPO certification for achieving its socioeconomic objectives remains uncertain. We evaluate the impact of certification on village-level well-being across Indonesia by applying counterfactual analysis to multi-dimensional government poverty data. We compare poverty across 36,311 villages between 2000 and 2018, tracking changes from before oil palm plantations were first established to several years after plantations were certified. Certification was associated with reduced poverty in villages with primarily market-based livelihoods, but not with those in which subsistence livelihoods were dominant before switching to oil palm. We highlight the importance of baseline village livelihood systems in shaping local impacts of agricultural certification, and assert that oil palm certification in certain village contexts may require additional resources to ensure socioeconomic objectives are realised
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Heterogeneous impacts of community forestry on forest conservation and poverty alleviation: evidence from Indonesia
1. Community forestry is a participatory approach aiming to achieve sustainable forest management while also reducing poverty among rural communities. Yet, evidence of the impacts of community forestry programmes on both forest conservation and poverty alleviation is scarce, and there is limited understanding of impacts across different social and biophysical contexts.
2. We applied a matching method to assess the extent to which deforestation has decreased and village well‐being has improved as a result of Indonesia's community forestry scheme, Hutan Desa (Village Forest). We assessed five dimensions of well‐being: basic (living conditions), physical (access to health and education), financial (income support), social (security and equity) and environmental (natural hazard prevention).
3. We found that Hutan Desa was associated with reduced deforestation and poverty. ‘Win‐win’ outcomes were found in 51% of cases, comprising (a) positive outcomes for both forests and poverty, (b) a positive outcome for one aspect and a negligible outcome for the other, or (c) a positive outcome for poverty in areas where natural forest had already been lacking prior to Hutan Desa tenure. Benefits to forests and people systematically differed depending on land‐use zones, reflecting subtle interactions between anthropogenic pressures and community livelihood characteristics.
4. In Watershed Protection Zones, which are dominated by subsistence‐based forest livelihoods, community forestry provided mild conservation benefits, but resulted in the greatest improvements in well‐being through improved land tenure. In Limited Production Zones, community forestry provided modest benefits for both conservation and well‐being because restrictions on timber harvest due to Hutan Desa designation reduced the financial well‐being of logging communities. The greatest conservation benefits were experienced in Permanent or Convertible Production Zones, but well‐being improvements were minimal. Here, living conditions and environmental well‐being were reduced due to pressure to intensify agricultural production under increased land scarcity in these predominantly cash crop‐oriented communities.
5. Our results highlight the spatial and contextual variation in impacts of community forestry policies on poverty alleviation and forest conservation outcomes. Crucially, our study provides vital objective information for future policy development in Indonesia and other tropical countries implementing community forestry schemes
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Toward improved impact evaluation of community forest management in Indonesia
Many tropical countries continue to devolve forest management to forest‐dwelling communities. The assumption is that local knowledge of forests and community engagement in forest management will attain multiple social and environmental co‐benefits, such as poverty alleviation and reduced deforestation and fires. Evidence for this, however, is scant, commonly hampered by data availability and a lack of technical capacity for implementing statistically robust impact evaluations. Based on a practice‐based review of policy implementation, impact evaluation of case studies and examples of counterfactual analyses from Indonesia, we demonstrate that it is increasingly feasible to determine the conditions under which community forest management will most likely achieve its social and environmental objectives. Adapting community forest management implementation based on feedback from accurate impact evaluation could lead to positive outcomes for people and environment in Indonesia, and across the tropical realm
Development of an ex vivo porcine lung model for studying growth, virulence, and signaling of Pseudomonas aeruginosa
Research into chronic infection by bacterial pathogens, such as Pseudomonas aeruginosa, uses various in vitro and live host models. While these have increased our understanding of pathogen growth, virulence, and evolution, each model has certain limitations. In vitro models cannot recapitulate the complex spatial structure of host organs, while experiments on live hosts are limited in terms of sample size and infection duration for ethical reasons; live mammal models also require specialized facilities which are costly to run. To address this, we have developed an ex vivo pig lung (EVPL) model for quantifying Pseudomonas aeruginosa growth, quorum sensing (QS), virulence factor production, and tissue damage in an environment that mimics a chronically infected cystic fibrosis (CF) lung. In a first test of our model, we show that lasR mutants, which do not respond to 3-oxo-C12-homoserine lactone (HSL)-mediated QS, exhibit reduced virulence factor production in EVPL. We also show that lasR mutants grow as well as or better than a corresponding wild-type strain in EVPL. lasR mutants frequently and repeatedly arise during chronic CF lung infection, but the evolutionary forces governing their appearance and spread are not clear. Our data are not consistent with the hypothesis that lasR mutants act as social “cheats” in the lung; rather, our results support the hypothesis that lasR mutants are more adapted to the lung environment. More generally, this model will facilitate improved studies of mi- crobial disease, especially studies of how cells of the same and different species interact in polymicrobial infections in a spatially structured environment
Acquisition of Growth-Inhibitory Antibodies against Blood-Stage Plasmodium falciparum
Background: Antibodies that inhibit the growth of blood-stage Plasmodium falciparum may play an important role in acquired and vaccine-induced immunity in humans. However, the acquisition and activity of these antibodies is not well understood. Methods: We tested dialysed serum and purified immunoglobulins from Kenyan children and adults for inhibition of P. falciparum blood-stage growth in vitro using different parasite lines. Serum antibodies were measured by ELISA to bloodstage parasite antigens, extracted from P. falciparum schizonts, and to recombinant merozoite surface protein 1 (42 kDa Cterminal fragment, MSP1-42). Results: Antibodies to blood-stage antigens present in schizont protein extract and to recombinant MSP1-42 significantly increased with age and were highly correlated. In contrast, growth-inhibitory activity was not strongly associated with age and tended to decline marginally with increasing age and exposure, with young children demonstrating the highest inhibitory activity. Comparison of growth-inhibitory activity among samples collected from the same population at different time points suggested that malaria transmission intensity influenced the level of growth-inhibitory antibodies. Antibodies to recombinant MSP1-42 were not associated with growth inhibition and high immunoglobulin G levels were poorly predictive of inhibitory activity. The level of inhibitory activity against different isolates varied. Conclusions: Children can acquire growth-inhibitory antibodies at a young age, but once they are acquired they do not appear to be boosted by on-going exposure. Inhibitory antibodies may play a role in protection from early childhood malaria
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