A dynamic modelling of safety nets

The nonlinear dynamic modelling of safety net systems is approached at different scales. For this purpose, the fundamental rope dynamic tests are the reference for two basic tools. One hand an anaytical bidimensional model with explicit geometrical nonlinearity and bilnear material law is proposed for preliminary design. On the other hand, a nonlinear explicit finite element is defined for numerical modelling of net systems. Semi-scale and full scale dynamic tests are performed to validate complete finite element models, suitable for global qualification of safety systems. The direct applications of these tools deal with explicit certification of safety systems for high-speed sport, such as downhill competitions

Establishing the zero-carbon performance of compact urban dwellings

This paper presents an analysis of the zero-carbon performance of a case-study building which is representative of a growing number of new buildings that are being built on redevelopment sites in inner-city areas in the UK. Compact urban dwellings are apartment style buildings with a floor area of 50 m2 per dwelling, often based over two floors. The constraints of this type of building on achieving zero-carbon performance in the context of the Code for Sustainable Homes is discussed and the shortcomings of the code are demonstrated in terms of the target heat and electricity demand targets for the design of the building systems. A graphical representation of the simulation results is used to present the findings. It has been demonstrated that in specific urban contexts, zero-carbon performance as defined within the current UK compliance framework may be very difficult to achieve in practice given the assumptions used in the simulation here. Therefore, it is very likely that zero-carbon compact urban dwellings may require a net off-site import of electrical and/or thermal energy

An air source heat pump model for operation in cold humid environments

There is considerable interest in the use of heat pumps as a potential low-carbon alternative to fossil fuel-based domestic space heating and hot water systems. In many cases, heat pumps are combined with other energy sources such as solar thermal and/or electric resistive heating, to ensure that building thermal loads can be met, and in order to minimise carbon emissions from such integrated systems. Whilst meeting the comfort demands in the occupied space, relatively complex control strategies are required in comparison to simple thermostatic control typically implemented to control gas fired heating systems in domestic buildings. Well characterised models of the principal components of these systems are required to explore and identify the most appropriate strategies in simulation. However, models of air source heat pumps (ASHPs) operating in humid climates, such as the UK, are limited. This paper presents an experimental setup designed to capture the operation of the ASHP in conditions similar to those found throughout a typical heating season in the UK. Results from a number of tests on a 10kW ASHP are presented in terms of the coefficient of performance (COP) and the steady-state operation are used to develop a model using empirical curve fitting. The overall maximum time constant is also established. The resulting model calculates COP as a function of air humidity, air temperature on the evaporator side and water temperature on the condenser side

Newborn and childhood differential DNA methylation and liver fat in school-age children

Background: Non-alcoholic fatty liver disease is the most common chronic liver disease in children in western countries. Adverse early-life exposures are associated with higher liver fat percentages in children. Differential DNA methylation may underlie these associations. We aimed to identify differential DNA methylation in newborns and children associated with liver fat accumulation in childhood. We also examined whether DNA methylation at 22 cytosine-phosphate-guanine sites (CpGs) associated with adult non-alcoholic fatty liver disease is associated with liver fat in children. Within a population-based prospective cohort study, we analyzed epigenome-wide DNA methylation data of 785 newborns and 344 10-year-old children in relation to liver fat fraction at 10 years. DNA methylation was measured using the Infinium HumanMethylation450 BeadChip (Illumina). We measured liver fat fraction by Magnetic Resonance Imaging. Associations of single CpG DNA methylation at the two-time points with liver fat accumulation were analyzed using robust linear regression models. We also analyzed differentially methylation regions using the dmrff package. We looked-up associations of 22 known adult CpGs at both ages with liver fat at 10 years. Results: The median liver fat fraction was 2.0% (95% range 1.3, 5.1). No single CpGs and no differentially methylated regions were associated with liver fat accumulation. None of the 22 known adult CpGs were associated with liver fat in children. Conclusions: DNA methylation at birth and in childhood was not associated with liver fat accumulation in 10-year-old children in this study. This may be due to modest sample sizes or DNA methylation changes being a consequence rather than a determinant of liver fat

Tensions and Luscher Terms for (2+1)-dimensional k-strings from Holographic Models

The leading term for the energy of a bound state of k-quarks and k-antiquarks is proportional to its separation L. These k-string configurations have a Luscher term associated with their quantum fluctuations which is typically a 1/L correction to the energy. We review the status of tensions and Luscher terms in the context of lattice gauge theory, Hamiltonian methods, and gauge/gravity correspondence. Furthermore we explore how different representations of the k-string manifest themselves in the gauge/gravity duality. We calculate the Luscher term for a strongly coupled SU(N) gauge theory in (2+1) dimensions using the gauge/gravity correspondence. Namely, we compute one-loop corrections to a probe D4-brane embedded in the Cvetic, Gibbons, Lu, and Pope supergravity background. We investigate quantum fluctuations of both the bosonic and the fermionic sectors.Comment: 39 pages, reference added, same version to be published in JHE

Diet quality in childhood: the Generation R Study

Purpose: We aimed to evaluate diet quality of 8-year-old children in the Netherlands, to identify sociodemographic and lifestyle correlates of child diet quality, and to examine tracking of diet quality from ea

Lactate and base deficit are predictors of mortality in critically ill patients with cancer

Cancer patients frequently require admission to intensive care unit. However, there are a few data regarding predictive factors for mortality in this group of patients. The aim of this study was to evaluate whether arterial lactate or standard base deficit on admission and after 24 hours can predict mortality for patients with cancer.Journal ArticleSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Lagrangian evolution of global strings

We establish a method to trace the Lagrangian evolution of extended objects consisting of a multicomponent scalar field in terms of a numerical calculation of field equations in three dimensional Eulerian meshes. We apply our method to the cosmological evolution of global strings and evaluate the energy density, peculiar velocity, Lorentz factor, formation rate of loops, and emission rate of Nambu-Goldstone (NG) bosons. We confirm the scaling behavior with a number of long strings per horizon volume smaller than the case of local strings by a factor of $\sim$ 10. The strategy and the method established here are applicable to a variety of fields in physics.Comment: 5 pages, 2 figure

New Tropical Peatland Gas and Particulate Emissions Factors Indicate 2015 Indonesian Fires Released Far More Particulate Matter (but Less Methane) than Current Inventories Imply

Deforestation and draining of the peatlands in equatorial SE Asia has greatly increased their flammability, and in September-October 2015 a strong El Niño-related drought led to further drying and to widespread burning across parts of Indonesia, primarily on Kalimantan and Sumatra. These fires resulted in some of the worst sustained outdoor air pollution ever recorded, with atmospheric particulate matter (PM) concentrations exceeding those considered "extremely hazardous to health" by up to an order of magnitude. Here we report unique in situ air quality data and tropical peatland fire emissions factors (EFs) for key carbonaceous trace gases (CO2, CH4 and CO) and PM2.5 and black carbon (BC) particulates, based on measurements conducted on Kalimantan at the height of the 2015 fires, both at locations of "pure" sub-surface peat burning and spreading vegetation fires atop burning peat. PM2.5 are the most significant smoke constituent in terms of human health impacts, and we find in situ PM2.5 emissions factors for pure peat burning to be 17.8 to 22.3 g·kg-1, and for spreading vegetation fires atop burning peat 44 to 61 g·kg-1, both far higher than past laboratory burning of tropical peat has suggested. The latter are some of the highest PM2.5 emissions factors measured worldwide. Using our peatland CO2, CH4 and CO emissions factors (1779 ± 55 g·kg-1, 238 ± 36 g·kg-1, and 7.8 ± 2.3 g·kg-1 respectively) alongside in situ measured peat carbon content (610 ± 47 g-C·kg-1) we provide a new 358 Tg (± 30%) fuel consumption estimate for the 2015 Indonesian fires, which is less than that provided by the GFEDv4.1s and GFASv1.2 global fire emissions inventories by 23% and 34% respectively, and which due to our lower EFCH4 produces far less (~3×) methane. However, our mean in situ derived EFPM2.5 for these extreme tropical peatland fires (28 ± 6 g·kg-1) is far higher than current emissions inventories assume, resulting in our total PM2.5 emissions estimate (9.1 ± 3.5 Tg) being many times higher than GFEDv4.1s, GFASv1.2 and FINNv2, despite our lower fuel consumption. We find that two thirds of the emitted PM2.5 come from Kalimantan, one third from Sumatra, and 95% from burning peatlands. Using new geostationary fire radiative power (FRP) data we map the fire emissions' spatio-temporal variations in far greater detail than ever before (hourly, 0.05°), identifying a tropical peatland fire diurnal cycle twice as wide as in neighboring non-peat areas and peaking much later in the day. Our data show that a combination of greatly elevated PM2.5 emissions factors, large areas of simultaneous, long-duration burning, and very high peat fuel consumption per unit area made these Sept to Oct tropical peatland fires the greatest wildfire source of particulate matter globally in 2015, furthering evidence for a regional atmospheric pollution impact whose particulate matter component in particular led to millions of citizens being exposed to extremely poor levels of air quality for substantial periods. © 2018 by the authors

Notes on nonnegative tensor factorization of the spectrogram for audio source separation : statistical insights and towards self-clustering of the spatial cues

International audienceNonnegative tensor factorization (NTF) of multichannel spectrograms under PARAFAC structure has recently been proposed by Fitzgerald et al as a mean of performing blind source separation (BSS) of multichannel audio data. In this paper we investigate the statistical source models implied by this approach. We show that it implicitly assumes a nonpoint-source model contrasting with usual BSS assumptions and we clarify the links between the measure of fit chosen for the NTF and the implied statistical distribution of the sources. While the original approach of Fitzgeral et al requires a posterior clustering of the spatial cues to group the NTF components into sources, we discuss means of performing the clustering within the factorization. In the results section we test the impact of the simplifying nonpoint-source assumption on underdetermined linear instantaneous mixtures of musical sources and discuss the limits of the approach for such mixtures