In our globalised food system, farmers meet domestic and transboundary food needs. As a result, the contribution of farmers to domestic food production is a poor proxy for their role in national... Show moreIn our globalised food system, farmers meet domestic and transboundary food needs. As a result, the contribution of farmers to domestic food production is a poor proxy for their role in national food security. This study offers the first global assessment of how small-, medium-, and large-scale farmers contribute to global food security. We find that the role of small-scale farmers in national and global food security has been significantly underestimated due to the localised focus of previous studies, particularly in high-income nations. Future research must account for the differentiated roles, impacts, and vulnerabilities of farmers within a global context. Show less
Chadians’ growing use of social media could prove a boon for the country’s political transition, but it could also fuel violence offline. With donor backing, authorities, civil society, online... Show moreChadians’ growing use of social media could prove a boon for the country’s political transition, but it could also fuel violence offline. With donor backing, authorities, civil society, online platforms and influencers should work to ensure social media remains a space for democratic debate rather than an accelerator of conflict. Show less
Recent years have seen a rise in awareness around “responsible metrics” and calls for research assessment reforms internationally. Yet within the field of quantitative science studies and in... Show moreRecent years have seen a rise in awareness around “responsible metrics” and calls for research assessment reforms internationally. Yet within the field of quantitative science studies and in research policy contexts, concerns about the limitations of evaluative bibliometrics are almost as old as the tools themselves. Given that many of the concerns articulated in recent reform movements go back decades, why has momentum for change grown only in the past ten years? In this paper, we draw on analytical insights from the sociology of social movements on collective action frames to chart the emergence, development, and expansion of “responsible metrics” as a professional reform movement. Through reviewing important texts that have shaped reform efforts, we argue that hitherto, three framings have underpinned the responsible metrics reform agenda: the metrics scepticism framing, the professional-expert framing, and the reflexivity framing. We suggest that while these three framings have co-existed within the responsible metrics movement to date, the “truce” negotiated between these framings may not last indefinitely, especially as the responsible metrics movement extends into wider research assessment reform movements. Show less
The human intestinal microbiome starts to form immediately after birth, and can greatly influence the health of the infant. During the first days facultative anaerobic species generally dominate,... Show moreThe human intestinal microbiome starts to form immediately after birth, and can greatly influence the health of the infant. During the first days facultative anaerobic species generally dominate, followed by a dominance of strictly anaerobic species, particularly Bifidobacterium species. An early transition to Bifidobacterium is associated with health benefits. To study the mechanisms of this transition and its hypothesised relation to oxygen, we introduce a multiscale mathematical model that considers metabolism, spatial bacterial population dynamics and resource sharing. Based on publicly available metabolic network data, the model predicts that differences in oxygen availability explain some of the observed individual variation in succession to anaerobic species. The model also predicts that anaerobic Bifidobacterium species become dominant through metabolizing lactose with a suboptimal yield, but a higher anaerobic growth rate than its competitors. The current work is the first step towards a more comprehensive understanding of the formation of a steady state adult colonic microbiota. Show less
Schleiffert, H.; Steegers, E.A.P.; Velpen, P. van der; Sombroek-van Doorm, M.P.; Rijlaarsdam, C.W. 2022
يتعلق هذا المقال بالعدالة الانتقالية في ليبيا. وهو يُظهر أنه على الرغم من جدّة مفهومها هناك – وإن قصر البعض الجدّة على المصطلح- فإن البلاد قد شهدت زخمًا كبيرًا في سن تشريعات عدل-انتقالية، ولكن هذا... Show moreيتعلق هذا المقال بالعدالة الانتقالية في ليبيا. وهو يُظهر أنه على الرغم من جدّة مفهومها هناك – وإن قصر البعض الجدّة على المصطلح- فإن البلاد قد شهدت زخمًا كبيرًا في سن تشريعات عدل-انتقالية، ولكن هذا الزخم لم يقترن بزخم في التطبيق، بالإضافة إلى قصور شاب هذا التشريع، وربما كان هو سبب غياب الزخم عن التطبيق. وفي فترات لاحقة، لقيت العدالة الانتقالية، مفهومًا وتشريعًا، تشكيكًا في جدواها ومكنة تطبيقها، وظهرت دعوات لاستبعادها، كلًا أو جزءًا، دائمًا أو مؤقتًا؛ تحقيقًا للمصالحة الوطنية. وقد كان للسياق السياسي مذ 2011 أثر كبير في ظهور هذه الدعوات وتطورها، كما كان له أيضًا أثره فيما قُّدِمَ من استجابات. ويجادل المقال بأن علاقة العدالة الانتقالية بالمصالحة الوطنية ليست متنافية، أي أنه لا يلزم من الأخذ بإحداها نفي الأخرى، بل العكس؛ أي أنه يلزم لتحقيق مصالحة وطنية مستدامة الأخذ بالعدالة الانتقالية. ويجادل أيضًا بأنه، على الرغم من جسامة التحديات، ما زالت هناك فرص لتحقيق العدالة الانتقالية.English version: https://hdl.handle.net/1887/3512148 Show less
This article is about transitional justice in Libya. It shows that despite the novelty of this concept in Libya- some authors argued that term is new in Libya, but the concept is not1- the country... Show moreThis article is about transitional justice in Libya. It shows that despite the novelty of this concept in Libya- some authors argued that term is new in Libya, but the concept is not1- the country has witnessed great momentum in enacting transitional justice legislation. However, this momentum was not accompanied by a momentum in implementation, in addition to, and perhaps because of, shortcomings associated with this legislation. In later periods, the feasibility and application of transitional justice, in concept and legislation, was questioned, and calls appeared to exclude it, in whole or in part, permanently or temporarily, in order to achieve national reconciliation. The political context since 2011 has had a significant impact on the emergence and development of these calls. It also had an impact on the responses provided. The article argues that the relationship of transitional justice with national reconciliation is not mutually exclusive, meaning that it is not necessary if one is accepted that the other is denied, but rather the opposite; That is, to achieve sustainable national reconciliation, transitional justice is required. The article also argues that, despite the enormity of the challenges, there are still opportunities to achieve transitional justice.Arabic version: https://hdl.handle.net/1887/3563576 Show less
Stacking domain boundaries occur in Van der Waals heterostacks whenever there is a twist angle or lattice mismatch between subsequent layers. Not only can these domain boundaries host topological... Show moreStacking domain boundaries occur in Van der Waals heterostacks whenever there is a twist angle or lattice mismatch between subsequent layers. Not only can these domain boundaries host topological edge states, imaging them has been instrumental to determine local variations in twisted bilayer graphene. Here, we analyse the mechanisms causing stacking domain boundary contrast in Bright Field Low-Energy Electron Microscopy (BF-LEEM) for both graphene on SiC, where domain boundaries are caused by strain and for twisted few layer graphene. We show that when domain boundaries are between the top two graphene layers, BF-LEEM contrast is observed due to amplitude contrast and corresponds well to calculations of the contrast based purely on the local stacking in the domain boundary. Conversely, for deeper-lying domain boundaries, amplitude contrast only provides a weak distinction between the inequivalent stackings in the domains themselves. However, for small domains phase contrast, where electrons from different parts of the unit cell interfere causes a very strong contrast. We derive a general rule-of-thumb of expected BF-LEEM contrast for domain boundaries in Van der Waals materials. Show less
Jong, T.A. de; Visser, L.; Jobst, J.; Tromp, R.M.; Molen, S.J. van der 2022
Terrace-sized, single-orientation graphene can be grown on top of a carbon buffer layer on silicon carbide by thermal decomposition. Despite its homogeneous appearance, a surprisingly large... Show moreTerrace-sized, single-orientation graphene can be grown on top of a carbon buffer layer on silicon carbide by thermal decomposition. Despite its homogeneous appearance, a surprisingly large variation in electron transport properties is observed.Here, we employ Aberration-Corrected Low-Energy Electron Microscopy (AC-LEEM) to study a possible cause of this variability. We characterize the morphology of stacking domains between the graphene and the buffer layer of high-quality samples. Similar to the case of twisted bilayer graphene, the lattice mismatch between the graphene layer and the buffer layer at the growth temperature causes a moiré pattern with domain boundaries between AB and BA stackings.We analyze this moiré pattern to characterize the relative strain and to count the number of edge dislocations. Furthermore, we show that epitaxial graphene on silicon carbide is close to a phase transition, causing intrinsic disorder in the form of co-existence of anisotropic stripe domains and isotropic trigonal domains. Using adaptive geometric phase analysis, we determine the precise relative strain variation caused by these domains. We observe that the step edges of the SiC substrate influence the orientation of the domains and we discuss which aspects of the growth process influence these effects by comparing samples from different sources. Show less
Several initiatives have been taken to promote the open availability of bibliographic metadata of scholarly publications in Crossref. We present an up-to-date overview of the availability of six... Show moreSeveral initiatives have been taken to promote the open availability of bibliographic metadata of scholarly publications in Crossref. We present an up-to-date overview of the availability of six metadata elements in Crossref: reference lists, abstracts, ORCIDs, author affiliations, funding information, and license information. Our analysis shows that the availability of these metadata elements has improved over time, at least for journal articles, the most common publication type in Crossref. However, the analysis also shows that many publishers need to make additional efforts to realize full openness of bibliographic metadata. Show less
The United Nations (UN) sanctions against North Korea are weakened by structural evasion techniques and weak enforcement. The African continent is a crucial node in the global illicit networks of... Show moreThe United Nations (UN) sanctions against North Korea are weakened by structural evasion techniques and weak enforcement. The African continent is a crucial node in the global illicit networks of North Korea. This paper examines three motives for African states to cooperate with North Korea, with a particular focus on the context of southern Africa: historical affinity (reciprocity), the practical issue of maintenance dependency (necessity), and the presence of weak enforcement regimes (opportunity). Based on a deep reading of UN Panel of Experts reports, academic literature and policy papers, novel archival material, and an interview with a defected North Korean diplomat, this paper argues that solutions to strengthen the sanctions regime can be successful only if they are grounded in African initiatives. Show less
Measures in the SARS-CoV-2 pandemic were based on rough ideas regarding transmission routes of pathogens. Quantified models of physical transmission routes are mostly lacking, a gap to be filled.... Show moreMeasures in the SARS-CoV-2 pandemic were based on rough ideas regarding transmission routes of pathogens. Quantified models of physical transmission routes are mostly lacking, a gap to be filled. Vaccines and medicines, important, are not studied here. We first survey main routes, from primary production in the alveoli and intestines to emissions, environmental routes, to exposure and alveolar infection. Next, specific routes are modelled, mostly at a preliminary state, open to systematic improvement. Starting from a standardized emitter, modelling results show extreme differences in potential exposure, in a range covering up to 4 orders of magnitude. The outcomes are pathogen-specific, already different between SARS-CoV-2 and influenza. Extreme exposures may result in smaller spaces; with lower ventilation rates; with a high density of emitting persons per m3; who stay there for several hours; and visitors staying more than a few minutes. In spaces where a build-up of concentrations is low, exposures are low, lowest in open air situations. A main conclusion for the next pandemic is that a quantified model can give strong guidance on where measures are primarily due. For SARS-CoV-2, ventilation can be improved short-term. Longer-term, effective ventilation rules and adaptation of buildings may reduce high exposures substantially. Show less
