Complex delay dynamics on railway networks: from universal laws to realistic modelling

Railways are a key infrastructure for any modern country. The reliability and resilience of this peculiar transportation system may be challenged by different shocks such as disruptions, strikes and adverse weather conditions. These events compromise the correct functioning of the system and trigger the spreading of delays into the railway network on a daily basis. Despite their importance, a general theoretical understanding of the underlying causes of these disruptions is still lacking. In this work, we analyse the Italian and German railway networks by leveraging on the train schedules and actual delay data retrieved during the year 2015. We use {these} data to infer simple statistical laws ruling the emergence of localized delays in different areas of the network and we model the spreading of these delays throughout the network by exploiting a framework inspired by epidemic spreading models. Our model offers a fast and easy tool for the preliminary assessment of the {effectiveness of} traffic handling policies, and of the railway {network} criticalities.Comment: 32 pages (with appendix), 28 Figures (with appendix), 2 Table

Worldwide Workshop on Youth Involvement as a Strategy for Social, Economic and Democratic Development

Summarizes January 2000 discussions on building capacity in the field of youth service. Explores connections with social capital, economic productivity, adolescent development, marginalized youth, civic engagement, and policy. Includes country summaries

Introduction: The intermittency of youth migration

This book presents different perspectives on youth migration, focusing upon research from a wide range of geographical contexts. While diverse, what theoretically unites the assembled chapters is the idea that migration as practised by young people has fragmented into disparate episodes. Rather than becoming migrants in the classical sense of following a path with a clear beginning, middle and end, young people tend to move intermittently, in a more circular manner and for different, frequently overlapping reasons such as education, work and training. They may not even see themselves as migrants—especially in the very early stages of a spatial trajectory—but when we take into account the accumulation of mobility experiences being consumed, starting with what may be relatively short duration stays abroad, we come to see that they are actually practising migration, albeit in a manner different to established ideas that centre on the idea of settlement. Another way of looking at this situation would be to see moves abroad during the youth phase as precursors to longer duration stays later in life. What happens at a young age hence comes to matter a great deal to professional development, as this can be the time of life when the knowledge and skills required to become a migrant are generated, along with an awareness of how to make effective decisions about where and when to go.info:eu-repo/semantics/acceptedVersio

Classical Tensors and Quantum Entanglement I: Pure States

The geometrical description of a Hilbert space asociated with a quantum system considers a Hermitian tensor to describe the scalar inner product of vectors which are now described by vector fields. The real part of this tensor represents a flat Riemannian metric tensor while the imaginary part represents a symplectic two-form. The immersion of classical manifolds in the complex projective space associated with the Hilbert space allows to pull-back tensor fields related to previous ones, via the immersion map. This makes available, on these selected manifolds of states, methods of usual Riemannian and symplectic geometry. Here we consider these pulled-back tensor fields when the immersed submanifold contains separable states or entangled states. Geometrical tensors are shown to encode some properties of these states. These results are not unrelated with criteria already available in the literature. We explicitly deal with some of these relations.Comment: 16 pages, 1 figure, to appear in Int. J. Geom. Meth. Mod. Phy

Mobility at the margins

The final part of this book looks at several undercurrents within youth mobility research, many of which have not featured prominently in mainstream studies in this field. In terming this section ‘mobility at the margins,’ there is also acknowledgement that while moving for education, work or training has been a relatively normative expectation for many young people for many years, there are still forms of youth circulation that are relatively undocumented or misunderstood, perhaps due to a certain level of discomfort in coming to terms with certain situations. Academic research has tended to emphasise the wide variety of individual lifestyle benefits and further professional possibilities available to young people who move, leaving the task of documenting the negative aspects to journalists, with policymakers perhaps preferring to finance interventions via civil society organizations (with limited budgets for conducting research) or focusing on issues that reflect politicians’ own beliefs rather than the voices of migrants. As such, we lack critical engagement with the consequences of exploitation within youth mobility, with a failure to recognize the unsustainability of the hegemonic neoliberal view of young people’s circulation as a means of generating economic capital for external parties such as universities. This extends to repercussions emerging from the rapid expansion of both the modes of travel and heightened levels of circulation, in addition to what are often quite obvious vulnerabilities within fragmented migration trajectories (see also Cairns 2021a, 2021b).info:eu-repo/semantics/acceptedVersio

Assessment of Vessel Density on Non-Contrast Computed Tomography to Detect Basilar Artery Occlusion

Introduction: Basilar artery occlusion (BAO) may be clinically occult due to variable and non-specific symptomatology. We evaluated the qualitative and quantitative determination of a hyperdense basilar artery (HDBA) on non-contrast computed tomography (NCCT) brain for the diagnosis of BAO.Methods: We conducted a case control study of patients with confirmed acute BAO vs a control group of suspected acute stroke patients without BAO. Two EM attending physicians, one third-year EM resident, and one medical student performed qualitative and quantitative assessments for the presence of a HDBA on axial NCCT images. Our primary outcome measures were sensitivity and specificity for BAO. Our secondary outcomes were inter-rater and intra-rater reliability of the qualitative and quantitative assessments.Results: We included 60 BAO and 65 control patients in our analysis. Qualitative assessment of the hyperdense basilar artery sign was poorly sensitive (54%–72%) and specific (55%–89%). Quantitative measurement improved the specificity of hyperdense basilar artery assessment for diagnosing BAO, with a threshold of 61.0–63.8 Hounsfield units demonstrating relatively high specificity of 85%–94%. There was moderate inter-rater agreement for the qualitative assessment of HDBA (Fleiss’ kappa statistic 0.508, 95% confidence interval: 0.435–0.581). Agreement improved for quantitative assessments, but still fell in the moderate range (Shrout-Fleiss intraclass correlation coefficient: 0.635). Intra-rater reliability for the quantitative assessments of the two attending physician reviewers demonstrated substantial consistency.Conclusion: Our results highlight the importance of carefully examining basilar artery density when interpreting the NCCT of patients with altered consciousness or other signs and symptoms concerning for an acute basilar artery occlusion. If the Hounsfield unit density of the basilar artery exceeds 61 Hounsfield units, BAO should be highly suspected

Coxiella burnetii Blocks Intracellular Interleukin-17 Signaling in Macrophages

Coxiella burnetii is an obligate intracellular bacterium and the etiological agent of Q fever. Successful host cell infection requires the Coxiella type IVB secretion system (T4BSS), which translocates bacterial effector proteins across the vacuole membrane into the host cytoplasm, where they manipulate a variety of cell processes. To identify host cell targets of Coxiella T4BSS effector proteins, we determined the transcriptome of murine alveolar macrophages infected with a Coxiella T4BSS effector mutant. We identified a set of inflammatory genes that are significantly upregulated in T4BSS mutant-infected cells compared to mock-infected cells or cells infected with wild-type (WT) bacteria, suggesting that Coxiella T4BSS effector proteins downregulate the expression of these genes. In addition, the interleukin-17 (IL-17) signaling pathway was identified as one of the top pathways affected by the bacteria. While previous studies demonstrated that IL-17 plays a protective role against several pathogens, the role of IL-17 during Coxiella infection is unknown. We found that IL-17 kills intracellular Coxiella in a dose-dependent manner, with the T4BSS mutant exhibiting significantly more sensitivity to IL-17 than WT bacteria. In addition, quantitative PCR confirmed the increased expression of IL-17 downstream signaling genes in T4BSS mutant-infected cells compared to WT- or mock-infected cells, including the proinflammatory cytokine genes Il1a, Il1b, and Tnfa, the chemokine genes Cxcl2 and Ccl5, and the antimicrobial protein gene Lcn2 We further confirmed that the Coxiella T4BSS downregulates macrophage CXCL2/macrophage inflammatory protein 2 and CCL5/RANTES protein levels following IL-17 stimulation. Together, these data suggest that Coxiella downregulates IL-17 signaling in a T4BSS-dependent manner in order to escape the macrophage immune response

Investigation of Cucumeropsis mannii N. seed oil as potential biodiesel feedstock

Biodiesels fuels are being explored worldwide as alternatives for fossil fuels. The seeds of “Werewere” (Cucumeropsis mannii N., Cucurbitaceae) a fruit vegetable plant in Ghana with high oil content were analysed for their fatty acid composition as well as fuel properties to ascertain their potential as biodiesel fuel. The seeds contained 37.15% oil. The extracted seed oil by GC/MS analysis consisted of mainly linoleic acid (18:2) accounting for 58.8% of the total fatty acids. Other fatty acids detected were oleic acid (C18:1), stearic acid (C18:0) and palmitic acid (C16:0,) with contribution of 15.5, 14.1 and 11.5% respectively. Among the fuel properties measured were density (889.9 kg/m3), cetane number (57), flash point (155oC) and pour point (-3oC). The measured fuel properties of the fatty acid methyl ester of the oil were comparable to both the ASTMD 6751 and the EN 14214 biodiesel standards. Fuel properties were essentially identical with those of soybean, safflower, sunflower and “egusi” biodiesel. The Kinematic viscosity was however measured to be 15. mm2/s a value higher than most biodiesel fuels reported in the literature.Keywords: Renewable energy, biodiesel, vegetable oil, transesterification, fatty acid methyl ester