The Scientific Committee confirms that the Threshold of Toxicological Concern (TTC) is a pragmatic screening and prioritisation tool for use in food safety assessment. This Guidance provides clear ...step‐by‐step instructions for use of the TTC approach. The inclusion and exclusion criteria are defined and the use of the TTC decision tree is explained. The approach can be used when the chemical structure of the substance is known, there are limited chemical‐specific toxicity data and the exposure can be estimated. The TTC approach should not be used for substances for which EU food/feed legislation requires the submission of toxicity data or when sufficient data are available for a risk assessment or if the substance under consideration falls into one of the exclusion categories. For substances that have the potential to be DNA‐reactive mutagens and/or carcinogens based on the weight of evidence, the relevant TTC value is 0.0025 μg/kg body weight (bw) per day. For organophosphates or carbamates, the relevant TTC value is 0.3 μg/kg bw per day. All other substances are grouped according to the Cramer classification. The TTC values for Cramer Classes I, II and III are 30 μg/kg bw per day, 9 μg/kg bw per day and 1.5 μg/kg bw per day, respectively. For substances with exposures below the TTC values, the probability that they would cause adverse health effects is low. If the estimated exposure to a substance is higher than the relevant TTC value, a non‐TTC approach is required to reach a conclusion on potential adverse health effects.
This publication is linked to the following EFSA Supporting Publications article: http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2019.EN-1661/full
Mooring cables are critical components of ocean renewable energy systems including offshore floating wind turbines and wave energy converters. Mooring cable dynamics is strongly nonlinear resulting ...from the geometric effect, hydrodynamic loads and probably seabed interactions. Time-domain methods are commonly used for numerical simulation. This study formulates a nonlinear frequency domain multi-harmonic balance method for efficient analysis of a mooring cable subjected to periodic fairlead motions. The periodic responses are of particular interest to investigate the mooring effect on the platform. In the formulation, the governing equations of the three-dimensional cable motions are spatially discretized using the finite difference method; the nonlinear ordinary differential equations are subsequently transformed into the frequency domain by expanding both the structural responses and the nonlinear nodal forces using truncated Fourier series, leading to a set of nonlinear algebraic equations of the Fourier coefficients. The equations are eventually solved using Newton's method where the alternating frequency/time domain method is used to handle the nonlinearity effect. The presented method is then compared to a time-domain method by numerical studies of a mooring cable. The results show that the method is of comparable accuracy as the time-domain method while it is generally more efficient. The proposed method shows promising results even when the cable tension becomes non-positive for a period of time during the cable motion, which is a known ill-posed problem for time-domain methods.
The Standards for the Reporting of Diagnostic Accuracy (STARD) statement, which was recently updated to the STARD2015 statement, was developed to encourage complete and transparent reporting of test ...accuracy studies. Although STARD principles apply broadly, the checklist is limited to studies designed to evaluate the accuracy of tests when the disease status is determined from a perfect reference procedure or an imperfect one with known measures of test accuracy. However, a reference standard does not always exist, especially in the case of infectious diseases with a long latent period. In such cases, a valid alternative to classical test evaluation involves the use of latent class models that do not require a priori knowledge of disease status. Latent class models have been successfully implemented in a Bayesian framework for over 20 years. The objective of this work was to identify the STARD items that require modification and develop a modified version of STARD for studies that use Bayesian latent class analysis to estimate diagnostic test accuracy in the absence of a reference standard. Examples and elaborations for each of the modified items are provided. The new guidelines, termed STARD-BLCM (Standards for Reporting of Diagnostic accuracy studies that use Bayesian Latent Class Models), will facilitate improved quality of reporting on the design, conduct and results of diagnostic accuracy studies that use Bayesian latent class models.
Brachycephalic syndrome (BS) is a pathophysiological disorder caused by excessive soft tissue within the upper airways of short-nosed dog breeds, causing obstruction of the nasal, pharyngeal and ...laryngeal lumen, resulting in severe respiratory distress. As the prevalence of BS appears to be high among some of the affected breeds, there is an urgent need for breeding efforts to improve the health status of those dogs. In the present study, we evaluated correlations between morphometric and other phenotypic characteristics and BS in a population of 69 French bulldogs from Denmark to identify parameters that could serve as a basis for breeding against BS. Furthermore, the genetic variation was monitored to determine whether it would be possible to breed based on these characteristics without simultaneously causing a critical reduction in genetic variation. Six phenotypic characteristics were correlated with the Brachycephalic Syndrome Functional (BSF) score. Among the morphometric risk factors, nostril stenosis (NS) and neck girth (NG) had the highest impact on the BSF score, accounting for 32% and 4% of the variation, respectively. The genetic variation in the population was comparable to other pure breeds, i.e. estimated and observed heterozygosity was 0.60 and the average inbreeding coefficient was 0.01. If only dogs with Grades 1 and 2 NS (no or only mild NS) were selected for breeding the mean BSF score would be reduced significantly. However, it would result in the exclusion of 81% of the population for breeding and this is not prudent. Excluding only dogs with severe stenosis (Grade 4) would exclude 50% of the population without any adverse impact on genetic variation within the population. Although exclusion of dogs with Grade 4 would result in an apparent reduction in the mean BSF score, this reduction is not significant. As NS accounts for 32% of the variation in BSF score, a possible long term strategy to reduce the prevalence of the BS in French bulldogs would seem to be a selection scheme that first excluded dogs with the most severe NS from breeding, gradually moving towards selecting dogs with lower NS grades. According to our findings there is no viable short term solution for reducing the prevalence of BS in the French bulldog population.
Description of animals' trophic niches helps us understand interactions between species in biological communities that are not easily observed. Analyses of macronutrient niches, that is, the range of ...macronutrient (protein:lipid:carbohydrate) ratios selected by generalist feeders, may be a useful alternative approach to inter‐species comparisons of diets, especially within taxonomic assemblages of predators where species with similar nutritional requirements are likely to accept similar types of prey.
Here we analysed the macronutritional niches of a woodland assemblage of seven harvestman species, all supposed to be predators with omnivorous tendencies. Five species (Mitopus morio, Leiobunum gracile, Oligolophus tridens, O. hanseni and Paroligolophus agrestis) were native and two species (Opilio canestrinii and Dicranopalpus ramosus) were recent invaders into the community.
We compare the fundamental (FMN) and realized (RMN) macronutritional niche positions of the species using a ‘double‐test procedure’, which provides information on whether the species were food limited in their natural habitat, and whether they were limited by specific macronutrients.
All seven species were food limited and six species were non‐protein limited in the field; of these, four species were carbohydrate limited, and in one species females were lipid limited and males were carbohydrate limited. These findings add to the notion that predators are mainly non‐protein limited in the field.
The FMN positions of the assemblage fell within 46%–50% protein, 29%–38% lipid and 16%–22% carbohydrate. The amount of carbohydrate in the self‐selected diet combined with carbohydrate limitation confirms that the species are zoophytophagous. Two morphological clusters of species (large long‐legged vs. small short‐legged species) differed not only in microhabitat (upper vs. lower forest strata) but also in macronutrient selection, where large long‐legged species selected higher proportion of carbohydrate than small short‐legged species. Thus, morphologically similar species occupy the same habitat stratum and have similar macronutritional niches.
We discuss the hypothesis that the invasive O. canestrinii might have an impact on native species as it allegedly had in urban environments previously. Two basic assumptions about interspecific resource competition were fulfilled, that is, high overlap of nutritional requirements and limitation by food and macronutrients.
Resumé
Undersøgelser af dyrs fødenicher kan hjælpe os til bedre at forstå de ofte usynlige interaktioner, der foregår mellem arter i biologiske samfund. Traditionelt er dyrs fødenicher blevet undersøgt ved at indsamle informationer om hvilke fødeemner de vælger (dvs hvilke plantearter en herbivor æder, hvilke byttedyr en prædator vælger), et ofte meget resursekrævende arbejde. Et nyudviklet supplement eller alternativ er at beskrive dyrenes makronæringsstof‐nicher, dvs hvilket forhold mellem protein, fedt og kulhydrat der vælges, når dyrene har frit valg til at sammensætte diæten. Sådanne undersøgelser kan ofte laves i laboratoriet med kunstige fødeemner og muliggør derfor undersøgelse af mange arter på samme tid. Denne tilgang er særlig relevant for generalister, der kan få de samme næringsstoffer fra mange forskellige fødeemner.
I dette studie undersøger vi makronæringsstof‐nicherne hos alle de syv samlevende arter af mejere i en dansk skov (Risskov). Af de syv arter er to nyligt indvandrede invasive arter (orange vægmejer, gaffelmejer), mens de fem er hjemmehørende (stor skovmejer, broget langbensmejer, lille skovmejer, lille murmejer, hedemejer).
Vi sammenligner arternes makronæringsstof‐nicher v.hj.a. to selv‐selektionsforsøg, i hvilke vi måler dyrenes samlede fødeoptagelse samt forholdet mellem protein, fedt og kulhydrat i denne: det første foretages umiddelbart efter dyrene er samlet i felten (den realiserede makronæringsstof‐niche (RMN)), og det andet efter en uge med rigelig og varieret fødetilgang i laboratoriet (den fundamentale makronæringsstof‐niche (FMN)). Forskellene mellem de to målinger fortæller os hvorvidt arterne er fødebegrænsede i felten, samt om de er begrænsede af specifikke makronæringsstoffer.
Vi finder at alle syv arter var fødebegrænsede i felten, og at seks af de syv var specifikt næringsstofbegrænsede. Fire arter var kulhydratbegrænsede; hos én art var hunnerne fedtbegrænsede mens hannerne var kulhydratbegrænsede; én art var non‐protein (dvs samlet fedt‐og‐kulhydrat) begrænset. Ingen arter var proteinbegrænsede.
Arternes fundamentale makronæringsstof‐nicher indeholdt 46%–50% protein, 29%–38% fedt og 16%–22% kulhydrat. Den relativt store andel af kulhydrat tyder på, at arterne ikke er rent karnivore, men supplerer diæten med fx sukker fra planter, evt honningdug. Efter deres størrelse (kropslængde, benlængde, vægt) danner arterne to grupper (store langbenede vs. små kortbenede). De store langbenede arter valgte højere indhold af kulhydrat end de små kortbenede. Arterne i begge grupper lignede deres gruppefæller mest ikke blot i størrelse, men også i habitatvalg (øvre og nedre strata i skoven) og i valg af makronæringsstoffer, i tilsyneladende modstrid med konkurrence‐ekslusions‐princippet.
Begge de invasive arter tilhører gruppen af store langbenede mejere og er derfor økologisk meget nær de to hjemmehørende arter af denne gruppe. Det kunne betyde at de hjemmehørende arter på længere sigt er truet af konkurrence fra de invasive arter. Vores resultater viser, at arterne har stort overlap i fødenicher og desuden er føde‐ og specifikt næringsstofbegrænsede, dvs at to væsentlige forudsætninger for fødekonkurrence mellem arterne er opfyldt.
To the author's knowledge, this is the first analysis of the macronutrient niche relations of a whole assemblage of species, including all three macronutrients (protein, lipid and carbohydrate), and combining estimates of niche size and overlap with measurements of food and nutrient limitation in the field.
Lateral tower vibrations of offshore wind turbines are normally lightly damped, and large amplitude vibrations induced by wind and wave loads in this direction may significantly shorten the fatigue ...life of the tower. This paper proposes the modeling and control of lateral tower vibrations in offshore wind turbines using active generator torque. To implement the active control algorithm, both the mechanical and power electronic aspects have been taken into consideration. A 13-degrees-of-freedom aeroelastic wind turbine model with generator and pitch controllers is derived using the Euler-Lagrangian approach. The model displays important features of wind turbines, such as mixed moving frame and fixed frame-defined degrees-of-freedom, couplings of the tower-blade-drivetrain vibrations, as well as aerodynamic damping present in different modes of motions. The load transfer mechanisms from the drivetrain and the generator to the nacelle are derived, and the interaction between the generator torque and the lateral tower vibration are presented in a generalized manner. A three-dimensional rotational sampled turbulence field is generated and applied to the rotor, and the tower is excited by a first order wave load in the lateral direction. Next, a simple active control algorithm is proposed based on active generator torques with feedback from the measured lateral tower vibrations. A full-scale power converter configuration with a cascaded loop control structure is also introduced to produce the feedback control torque in real time. Numerical simulations have been carried out using data calibrated to the referential 5-MW NREL (National Renewable Energy Laboratory) offshore wind turbine. Cases of drivetrains with a gearbox and direct drive to the generator are considered using the same time series for the wave and turbulence loadings. Results show that by using active generator torque control, lateral tower vibrations can be significantly mitigated for both gear-driven and direct-driven wind turbines, with modest influence on the smoothness of the power output from the generator.
I use Danish administrative data to investigate the consequences of summer camp participation combined with a one-year follow-up program for disadvantaged boys on academic, personal, and social ...competencies. My identification strategy relies on individual-level panel data that enable me to observe outcomes before and after summer camp participation. Using a difference-in-differences strategy, I find overall positive effects on academic and personal competencies that reduce the gap to a matched group of boys with similar background characteristics by 40 to 80 percent. Further, I exploit a structural change in the follow-up program to evaluate how different mentoring strategies affect outcomes. In 2017, the follow-up program was changed from individual mentoring to group mentoring. Using a triple differences strategy, I find that group mentoring in the follow-up program improves personal and social competencies, suggesting that the format of the follow-up program is crucial for effects on personal and social competencies.
•The effects of summer camp and mentoring follow-up programs on human capital.•Reforming mentoring strategy enables investigation of the most effective follow-up.•Summer camp with follow-up improve education readiness and academic performance.•Group mentoring follow-up enhances personal and social competencies.
The majority of out-of-hospital cardiac arrests (OHCAs) occur in residential locations, but knowledge about strategic placement of automated external defibrillators in residential areas is lacking. ...We examined whether residential OHCA areas suitable for placement of automated external defibrillators could be identified on the basis of demographic characteristics and characterized individuals with OHCA in residential locations.
We studied 4828 OHCAs in Copenhagen between 1994 and 2005. The incidence and characteristics of OHCA were examined in every 100 x 100-m (109.4 x 109.4-yd) residential area according to its underlying demographic characteristics. By combining > or =2 demographic characteristics, it was possible to identify 100 x 100-m (109.4 x 109.4-yd) areas with at least 1 arrest every 5.6 years (characterized by >300 persons per area and lowest income) to 1 arrest every 4.3 years (characterized by >300 persons per area, lowest income, low education, and highest age). These areas covered 9.0% and 0.8% of all residential OHCAs, respectively. Individuals with OHCA in residential locations differed from public ones in that the patients were older (70.6 versus 60.6 years; P<0.0001), the ambulance response interval was longer (6.0 versus 5.0 minutes; P<0.0001), arrests occurred more often at night (21.2% versus 11.2%; P<0.0001), the patients had ventricular fibrillation less often (12.8% versus 38.1%; P<0.0001), and the patients had a worse 30-day survival rate (3.2% versus 13.9%; P<0.0001).
On the basis of simple demographic characteristics of a city center, we could identify residential areas suitable for automated external defibrillator placement. Individuals with OHCA in residential locations were more likely to have characteristics associated with poor outcome compared with public arrests.
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