The impact of metropolitan structure on commute behavior in the Netherlands: a multilevel approach

The effect of decentralization of land uses on travel behavior remains an unresolved issue in the academic literature. Some US researchers argue that a tendency towards polycentrism is associated with decreasing commute times and distances. Others have, however, suggested and shown the opposite commute times and distances tend to be longer in polycentric than in monocentric urban areas. Using this controversy as a starting point, we analyse how monocentric and polycentric urban structures affect commuting in the Netherlands with data from the 1998 National Travel Survey. Four kinds of urban systems are distinguished: one monocentric and three polycentric systems. In contrast to most previous work, we use multilevel regression analysis to take adequate account of the effects of individual and household attributes. The results indicate that urban structure influences most dimensions of commuting considered here. Yet, individual and household level variables are more important determinants than characteristics of the residential and workplace environment. Gender, household type and their interaction effects remain important determinants of commute behavior in the Netherlands; particularly women in two-earner households commute less than average. Education and income are both positively related to the amount of commuting. Further, the effects of mono- and polycentrism on commuting are more complicated than the literature makes us believe. When individual and household level factors are taken account of, polycentrism does not always result in more efficient commute patterns than monocentric urban structures: in most polycentric urban areas commute distances and times are longer than in monocentric ones. Only when polycentric regions consist of several relatively independent and self-contained development nodes are commute distances shorter than elsewhere. Commute times are in that case comparable to those in monocentric urban areas. The impact of urban structure disappears when commute time is related to the time spent on work activities; the ratio between commute time and work duration is not much affected by the type of urban system in which workers reside. The fact that commute times and distances are not lower in polycentric urban areas may be attributed to the specific situation in the Netherlands: strong spatial planning policies may have obstructed the relocation of employment and housing in close proximity of each other. However, the longer commute in most policentric regions may also indicate that workers and their households not always behave as urban economic theory predicts. In any case, the results show that it is necessary to distinguish several types of polycentric systems instead of merely using a dichotomy of monocentric and polycentric in the analysis of commuting.

Ecosystem Level Effects of Climate Change on Northern Peatlands

Northern peatlands are the world’s most efficient terrestrial ecosystems at storing carbon. The effects of global climate change are expected to be intensified in high latitude regions of the northern hemisphere, where peatlands are a dominant landscape feature. Accordingly, there is concern that climate change will change peatlands from carbon sinks into carbon sources. In order to better understand the impacts of climate change on peatland ecosystems, the research presented in this dissertation focuses on several mesocosm experiments conducted to develop a better understanding of the interactive effects of three key climate change stressors (increased atmospheric CO2, increased temperature, decreased water table elevation) on northern peatland vegetation structure and carbon cycling functions. Experimental findings include observations that temperatures between 4 and 8°C above ambient conditions triggered a plant community restructuring event, supporting the expansion of graminoids at the expense of Sphagnum mosses. This change in plant community was associated with an increase in dissolved organic carbon (DOC) concentration and lability, characteristics that indicate enhanced carbon release and a threat to northern peatland carbon stores. These findings were extended through further analysis to determine that differences in plant community structure were mechanistically linked to changes in carbon cycling functions through the introduction of microbial priming-like effects. Specifically, rooting growth forms increased belowground DOC lability, stimulating microbial activity and increasing respired CO2 rates — likely through the introduction of simple root exudates. These findings were then placed into the broader context of northern peatland climate change research using stable state theory as a framework to clarify the key factors that threaten peatland stability, point towards disturbance thresholds, and provide insights on the short- and long-term impacts of state shifts on northern peatland carbon uptake and storage

Experimental verification of entanglement generated in a plasmonic system

A core process in many quantum tasks is the generation of entanglement. It is being actively studied in a variety of physical settings - from simple bipartite systems to complex multipartite systems. In this work we experimentally study the generation of bipartite entanglement in a nanophotonic system. Entanglement is generated via the quantum interference of two surface plasmon polaritons in a beamsplitter structure, i.e. utilising the Hong-Ou-Mandel (HOM) effect, and its presence is verified using quantum state tomography. The amount of entanglement is quantified by the concurrence and we find values of up to 0.77 +/- 0.04. Verifying entanglement in the output state from HOM interference is a nontrivial task and cannot be inferred from the visibility alone. The techniques we use to verify entanglement could be applied to other types of photonic system and therefore may be useful for the characterisation of a range of different nanophotonic quantum devices.Comment: 7 pages, 4 figure

Governance and human resources for health

Despite an increase in efforts to address shortage and performance of Human Resources for Health (HRH), HRH problems continue to hamper quality service delivery. We believe that the influence of governance is undervalued in addressing the HRH crisis, both globally and at country level. This thematic series has aimed to expand the evidence base on the role of governance in addressing the HRH crisis. The six articles comprising the series present a range of experiences. The articles report on governance in relation to developing a joint vision, building adherence and strengthening accountability, and on governance with respect to planning, implementation, and monitoring. Other governance issues warrant attention as well, such as corruption and transparency in decision-making in HRH policies and strategies. Acknowledging and dealing with governance should be part and parcel of HRH planning and implementation. To date, few experiences have been shared on improving governance for HRH policy making and implementation, and many questions remain unanswered. There is an urgent need to document experiences and for mutual learning

Observation of quantum interference in the plasmonic Hong-Ou-Mandel effect

We report direct evidence of the bosonic nature of surface plasmon polaritons (SPPs) in a scattering-based beamsplitter. A parametric down-conversion source is used to produce two indistinguishable photons, each of which is converted into a SPP on a metal-stripe waveguide and then made to interact through a semi-transparent Bragg mirror. In this plasmonic analog of the Hong-Ou-Mandel experiment, we measure a coincidence dip with a visibility of 72%, a key signature that SPPs are bosons and that quantum interference is clearly involved.Comment: 5 pages, 3 figure

Syndemic contexts: findings from a review of research on non-communicable diseases and interviews with experts

Background Syndemics are characterized by the clustering of two or more health conditions, their adverse interaction, and contextual factors that create the conditions for clustering and/or interaction that worsens health outcomes. Studying syndemics entails drawing on diverse disciplines, including epidemiology and anthropology. This often means collaboration between researchers with different scholarly backgrounds, who share and – ideally – integrate their findings. Objective This article examines how context within syndemics has been defined and studied. Methods A literature review of empirical studies focusing on syndemics involving non-communicable diseases (NCDs) and mental health conditions was conducted and the full text of 13 articles was analyzed. The review was followed-up with semi-structured interviews with 11 expert researchers working in the field. Results The review and interviews highlighted a relatively consistent definition of syndemics. The reviewed studies of NCD-related syndemics tended to focus on micro-level context, suggesting a need to analyze further underlying structural factors. In their syndemics research, respondents described working with other disciplines and, although there were some challenges, welcomed greater disciplinary diversity. Methodological gaps, including a lack of mixed methods and longitudinal studies, were identified, for which further interdisciplinary collaborations would be beneficial. Conclusions NCD-related syndemics research would benefit from further analysis of structural factors and the interconnections between syndemic components across multiple levels, together with more ambitious research designs integrating quantitative and qualitative methods. Research on the COVID-19 pandemic can benefit from a syndemics approach, particularly to understand vulnerability and the unequal impacts of this public health crisis

Observation of Andreev Reflection Enhanced Shot Noise

We have experimentally investigated the quasiparticle shot noise in NbN/MgO/NbN superconductor - insulator - superconductor tunnel junctions. The observed shot noise is significantly larger than theoretically expected. We attribute this to the occurrence of multiple Andreev reflection processes in pinholes present in the MgO barrier. This mechanism causes the current to flow in large charge quanta (Andreev clusters), with a voltage dependent average value of m = 1+ 2 Delta/eV times the electron charge. Because of this charge enhancement effect, the shot noise is increased by the factor m.Comment: 4 pages, 5 figures include

Allelic diversity of HMW and LMW glutenin subunits and ω-gliadins in Canadian hard red spring bread wheat (Triticum aestivum L.) developed over 150 years

Non-Peer ReviewedWheat (Triticum aestivum L.) is a major cereal crop that is grown around the world. Wheat based products are an important component of human diet as source of calories and proteins. The wheat grain storage proteins are made up of glutenin and gliadin subunits that form gluten in the dough, when wheat flour is mixed with water. The viscoelastic properties of wheat dough lend itself to make diverse food products consumed around the world. During the past few years, wheat gluten has been blamed for increased incidence of some chronic diseases such as obesity and associated cardiovascular ailments and type-2 diabetes. The main objective of this study was to study the diversity in wheat glutenins and gliadins, the two proteins that make up gluten, during 150 years of wheat improvement in Canada. A set of 37 hard red spring wheat cultivars were grown during 2013 and 2014, in a randomized complete block design with four replicates at the Kernen farm, University of Saskatchewan. Cultivars were selected based on the year of release from 1860 to 2007 and subdivided into historical and modern wheats. Historical cultivars included 11 entries released in Canada from 1860 until 1935 and the modern group included 26 cultivars released after 1935 and up to 2007. Gluten protein composition was determined by SDS-PAGE. Most of the genotypes in both groups had the combination Glu-A1b (2*), Glu-B1c (7+9) and Glu-D1d (5+10) for the high molecular weight glutenins (HMW-GS). Another allele that remained stable was the low molecular weight glutenin (LMW-GS) Glu-A3e present in 91% (historical) to 58% (modern) of the cultivars. Most variation was observed in the frequency of appearance of the most common subunits in the LMW-GS Glu-B3 and Glu-D3. For instance, in the historical group, the most common alleles were the Glu-B3b’ (55%) and the Glu-D3a (37%) or Glu-D3b (36%) whereas in modern cultivars Glu-B3h (58%) and the Glu-D3c (58%) were most frequent. Regarding ω-gliadins encoded by the Gli-B1, a relative high proportion of the historical genotypes carried the Gli-B1b subunit whereas in modern cultivars the Gli-B1d (58%) was common. No major alterations in the gluten subunits were observed between the Canadian historical and modern hard red spring wheat cultivars developed over the last century and half. However, subtle differences were found in the HMW-GS and the LMW-GS Glu-A3, and the frequency of appearance in the Glu-D3 and Glu-B3 (LMW-GS) and the Gli-B1 (ω-gliadins). The impact of the alterations on the incidence of Celiac disease is currently being studied