11 research outputs found
A Decentralised Digital Identity Architecture
Current architectures to validate, certify, and manage identity are based on
centralised, top-down approaches that rely on trusted authorities and
third-party operators. We approach the problem of digital identity starting
from a human rights perspective, with a primary focus on identity systems in
the developed world. We assert that individual persons must be allowed to
manage their personal information in a multitude of different ways in different
contexts and that to do so, each individual must be able to create multiple
unrelated identities. Therefore, we first define a set of fundamental
constraints that digital identity systems must satisfy to preserve and promote
privacy as required for individual autonomy. With these constraints in mind, we
then propose a decentralised, standards-based approach, using a combination of
distributed ledger technology and thoughtful regulation, to facilitate
many-to-many relationships among providers of key services. Our proposal for
digital identity differs from others in its approach to trust in that we do not
seek to bind credentials to each other or to a mutually trusted authority to
achieve strong non-transferability. Because the system does not implicitly
encourage its users to maintain a single aggregated identity that can
potentially be constrained or reconstructed against their interests,
individuals and organisations are free to embrace the system and share in its
benefits.Comment: 30 pages, 10 figures, 3 table
Can Cryptocurrencies Preserve Privacy and Comply with Regulations?
Cryptocurrencies offer an alternative to traditional methods of electronic
value exchange, promising anonymous, cash-like electronic transfers, but in
practice they fall short for several key reasons. We consider the false choice
between total surveillance, as represented by banking as currently implemented
by institutions, and impenetrable lawlessness, as represented by
privacy-enhancing cryptocurrencies as currently deployed. We identify a range
of alternatives between those two extremes, and we consider two potential
compromise approaches that offer both the auditability required for regulators
and the anonymity required for users.Comment: 20 pages, 10 figures, 3 table
A Scalable Architecture for Electronic Payments
We present a scalable architecture for electronic retail payments via central
bank digital currency and offer a solution to the perceived conflict between
robust regulatory oversight and consumer affordances such as privacy and
control. Our architecture combines existing work in payment systems and digital
currency with a new approach to digital asset design for managing unforgeable,
stateful, and oblivious assets without relying on either a central authority or
a monolithic consensus system. Regulated financial institutions have a role in
every transaction, and the consumer affordances are achieved through the use of
non-custodial wallets that unlink the sender from the recipient in the
transaction channel. This approach is fully compatible with the existing
two-tiered banking system and can complement and extend the roles of existing
money services businesses and asset custodians.Comment: 24 pages, 7 figures, 2 table
Crop pests and predators exhibit inconsistent responses to surrounding landscape composition
The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies
The Forgotten Preconditions for a Well-Functioning Internet
For decades, proponents of the Internet have promised that it would one day
provide a seamless way for everyone in the world to communicate with each
other, without introducing new boundaries, gatekeepers, or power structures.
What happened? This article explores the system-level characteristics of a key
design feature of the Internet that helped it to achieve widespread adoption,
as well as the system-level implications of certain patterns of use that have
emerged over the years as a result of that feature. Such patterns include the
system-level acceptance of particular authorities, mechanisms that promote and
enforce the concentration of power, and network effects that implicitly
penalise those who do not comply with decisions taken by privileged actors. We
provide examples of these patterns and offer some key observations, toward the
development of a general theory of why they emerged despite our best efforts,
and we conclude with some suggestions on how we might mitigate the worst
outcomes and avoid similar experiences in the future.Comment: 11 pages, 1 figur
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Crop pests and predators exhibit inconsistent responses to surrounding landscape composition.
The idea that noncrop habitat enhances pest control and represents a win-win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win-win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies
A genome-wide investigation of the worldwide invader Sargassum muticum shows high success albeit (almost) no genetic diversity
Twenty years of genetic studies of marine invaders have shown that successful invaders are often characterized by native and introduced populations displaying similar levels of genetic diversity. This pattern is presumably due to high propagule pressure and repeated introductions. The opposite pattern is reported in this study of the brown seaweed, Sargassum muticum, an emblematic species for circumglobal invasions. Albeit demonstrating polymorphism in the native range, microsatellites failed to detect any genetic variation over 1,269 individuals sampled from 46 locations over the Pacific-Atlantic introduction range. Single-nucleotide polymorphisms (SNPs) obtained from ddRAD sequencing revealed some genetic variation, but confirmed severe founder events in both the Pacific and Atlantic introduction ranges. Our study thus exemplifies the need for extreme caution in interpreting neutral genetic diversity as a proxy for invasive potential. Our results confirm a previously hypothesized transoceanic secondary introduction from NE Pacific to Europe. However, the SNP panel unexpectedly revealed two additional distinct genetic origins of introductions. Also, conversely to scenarios based on historical records, southern rather than northern NE Pacific populations could have seeded most of the European populations. Finally, the most recently introduced populations showed the lowest selfing rates, suggesting higher levels of recombination might be beneficial at the early stage of the introduction process (i.e., facilitating evolutionary novelties), whereas uniparental reproduction might be favored later in sustainably established populations (i.e., sustaining local adaptation).Agence Nationale de la Recherche - ANR-10-BTBR-04; European Regional Development Fund; Fundacao para a Ciencia e a Tecnologia - SFRH/BPD/107878/2015, UID/Multi/04326/2016, UID/Multi/04326/2019; Brittany Region;info:eu-repo/semantics/publishedVersio
Data from: Crop pests and predators exhibit inconsistent responses to surrounding landscape composition
The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies