164 research outputs found
Analysis of forensic DNA mixtures with artefacts
No full textDNA is now routinely used in criminal investigations and court cases, although DNA samples taken at crime scenes are of varying quality and therefore present challenging problems for their interpretation. We present a statistical model for the quantitative peak information obtained from an electropherogram of a forensic DNA sample and illustrate its potential use for the analysis of criminal cases. In contrast with most previously used methods, we directly model the peak height information and incorporate important artefacts that are associated with the production of the electropherogram. Our model has a number of unknown parameters, and we show that these can be estimated by the method of maximum likelihood in the presence of multiple unknown individuals contributing to the sample, and their approximate standard errors calculated; the computations exploit a Bayesian network representation of the model. A case example from a UK trial, as reported in the literature, is used to illustrate the efficacy and use of the model, both in finding likelihood ratios to quantify the strength of evidence, and in the deconvolution of mixtures for finding likely profiles of the individuals contributing to the sample. Our model is readily extended to simultaneous analysis of more than one mixture as illustrated in a case example. We show that the combination of evidence from several samples may give an evidential strength which is close to that of a single-source trace and thus modelling of peak height information provides a potentially very efficient mixture analysis
Greenland’s contribution to global sea-level rise by the end of the 21st century
No full textThe Greenland ice sheet holds enough water to raise the global sea level with ~7 m. Over the last few decades, observations manifest a substantial increase of the mass loss of this ice sheet. Both enhanced melting and increase of the dynamical discharge, associated with calving at the outlet-glacier fronts, are contributing to the mass imbalance. Using a dynamical and thermodynamical ice-sheet model, and taking into account speed up of outlet glaciers, we estimate Greenland’s contribution to the 21st century global sea-level rise and the uncertainty of this estimate. Boundary fields of temperature and precipitation extracted from coupled climate-model projections used for the IPCC Fourth Assessment Report, are applied to the icesheet model. We implement a simple parameterization for increased flow of outlet glaciers, which decreases the bias of the modeled present-day surface height. It also allows for taking into account the observed recent increase in dynamical discharge, and it can be used for future projections associated with outlet-glacier speed up. Greenland contributes 0–17 cm to global sea-level rise by the end of the 21st century. This range includes the uncertainties in climate-model projections, the uncertainty associated with scenarios of greenhouse-gas emissions, as well as the uncertainties in future outlet-glacier discharge. In addition, the range takes into account the uncertainty of the ice-sheet model and its boundary fields
EURO-Carbon Full Dataset
No full textThe dataset EURO-CARBON_Dataset_v1.0 contains some errors and a new version including the changes below is being prepared ASAP (no later than 31 August 2025).
In the meantime, we recommend making the following changes before using the database:
- The dry bulk density values in the following cells should be removed: 46326-46596
- Entries marked as “Bare sediment” in “Habitat” should be changed to “Seagrass (Zostera marina)”.
- Please also add a note indicating whether the Zostera marina beds were sparse or dense: 30554-30562 (Dense); 30563-30572 (Sparse) ; 30581-50588 (Dense); 30589- 30597 (Sparse); 30607-30615 (Dense); 30616-30617 (Sparse); 30627-30630 (Dense); 30631-30639 (Sparse); 30649-30656 (Dense); 30657-30664 (Sparse); 30671-30676 (Dense); 30683-30689 (Sparse); 30690-30696 (Dense); 30697-30703 (Sparse); 30710-30716 (Dense); 30725-30736 (Sparse); 30737-30740 (Dense); 30741-30742 (Sparse); 30743-30744 (Dense); 30751-30756 (Sparse); 30763-30768 (Dense); 30769-30774 (Sparse); 30775-30780 (Dense); 30788-30796 (Sparse); 30797-30803 (Dense); 30810-30815 (Sparse); 30823-30834 (Dense); 30835-30841 (Sparse); 30848-30849 (Sparse); 30850- 30853 (Dense); 30854-30855 (Sparse); 30862-30865 (Sparse); 30866-30869 (Dense); 30876-30882 (Sparse); 30883-30889 (Dense); 30897-30898 (Sparse); 30899-30901 (Dense); 30902-30904 (Sparse); 30910-30914 (Dense); 30915- 30916 (Sparse); 30917-30918 (Dense); 30919-30922 (Sparse); 30929-30934 (Sparse); 30935-30941 (Dense).
- Please note that the column of MAR (g/cm2/year) and the associated MAR_se column includes several unit inconsistencies. We recommend not using these columns unless the following corrections are made: 12445-12469: MAR values are reported in g/cm2/ka instead of g/cm2/year; 29652-29765; MAR values are reported in g/m2/year instead of g/cm2/year; 37970-37993: MAR values should be deleted; 38018-38036: MAR values should be deleted; 38095-38118: MAR values should be deleted; 43520-43526: All MAR values in this core should be 0.017g/cm2/year; 43534-43541: All MAR values in this core should be 0.019 g/cm2/year; 43549-43558: All MAR values in this core should be 0.074 g/cm2/year; 43563-43572: All MAR values in this core should be 0.069 g/cm2/year; 48987-50177: MAR values are reported in g/cm2/ka instead of g/cm2/year; 50306-50339: MAR values are reported in g/cm2/ka instead of g/cm2/year; 50434-50534: MAR values are reported in g/cm2/ka instead of g/cm2/year.
- Please in 50434-50534 replace the wrong DOI with Correct: https://doi.pangaea.de/10.1594/PANGAEA.55155This is document is part of a deliverable not yet approved by the European Commission. The file represents the first “EURO-CARBON” full dataset on blue carbon in marine sediments of the European seas, which is described in detailed in the paper Graversen et al. (2025) A marine and salt marsh sediment organic carbon database for European regional seas (EURO-CARBON) Data in Brief Volume 60, June 2025, 111595, https://doi.org/10.1016/j.dib.2025.111595This work contributes to the Institut de Ciències del Mar "Severo Ochoa Centre of Excellence" accreditation CEX2024-001494-S funded by AEI 10.13039/501100011033 of the Spanish Ministry of Science and InnovationPeer reviewe
Relational Contracting and Allocation of Decision Rights in the Agri-Food Industry: Producer Contracts and Food Safety
No full textWe apply a formal theoretical model of adaptation to two empirical settings within the agri-food industry: specialized pig production and food safety in Denmark. The objective is to allocate decision rights ex ante so that actual decisions taken ex post will optimize the profit accruing to the two parties in a contractual or integrative relation. Two applications are presented in this paper: First an actual partnership between two pork producers in Denmark. Based on detailed budgets we develop detailed schedules for the “reneging temptations” of the two partners- These are the temptations to renege on the contract during the evolution of the partnership. Using a model developed by Baker, Gibbons and Murphy (2006) we calculate equilibria using the Folk theorem in order to determine which is the best allocation of decision rights. We find that the existing allocation of decision rights in the case we examine is efficient in the sense that it results into a second best allocation. Using the same modelling approach we present a second application on salmonella control related to end-feeding, that is, salmonella contamination of pork due to filled bellies of pigs fed for the last 12 hours before delivery. Based on appropriate assumptions, the parties should give the decision right (whether to end-feed or not) to the slaughterhouse in order to reach the firstbest solution which, given the assumptions, is feasibleTheory of the firm, Adaptation theory, Contracts, Decision Rights, Pig production, Food safety, Agribusiness, Agricultural and Food Policy, Farm Management, Food Consumption/Nutrition/Food Safety, Industrial Organization, D21, L2, Q1,
Power variation & stochastic volatility: a review and some new results
No full textIn this paper we review some recent work on limit results on realised power variation, that is sums of powers of absolute increments of various semimartingales. A special case of this analysis is realised variance and its probability limit, quadratic variation. Such quantities often appear in financial econometrics in the analysis of volatility. The paper also provides some new results and discusses open issues.Bipower; Mixed Gaussian limit; Power variation; Quadratic variation; Realised variance; Realised volatility; Stochastic volatility.
Arctic winter warming amplified by the thermal inversion and consequent low infrared cooling to space
No full textPronounced warming in the Arctic region, coined Arctic amplification, is an important feature of observed and modelled climate change1, 2. Arctic amplification is generally attributed to the retreat of sea-ice3 and snow, and the associated surface-albedo feedback4, in conjunction with other processes5, 6, 7, 8. In addition, the predominant thermal surface inversion in winter has been suggested to pose a negative feedback to Arctic warming by enhancing infrared radiative cooling9. Here we use the coupled climate model EC-Earth10 in idealized climate change experiments to quantify the individual contributions of the surface and the atmosphere to infrared radiative cooling. We find that the surface inversion in fact intensifies Arctic amplification, because the ability of the Arctic wintertime clear-sky atmosphere to cool to space decreases with inversion strength. Specifically, we find that the cold layers close to the surface in Arctic winter, where most of the warming takes place, hardly contribute to the infrared radiation that goes out to space. Instead, the additional radiation that is generated by the warming of these layers is directed downwards, and thus amplifies the warming. We conclude that the predominant Arctic wintertime temperature inversion damps infrared cooling of the system, and thus constitutes a positive warming feedback
Predicting avalanche danger in northern Norway using statistical models
No full textSnow avalanches are one of the most impactful natural hazards in mountainous areas. Thus, the assessment and forecasting of avalanche danger are of great importance for the protection of life and property. A changing climate may lead to changes in avalanche danger, although the manifestation is unclear. Since climate change is regionally different, an assessment of potential avalanche-danger changes should be conducted on a regional basis. Here the focus is on avalanche danger in the Troms region in northern Norway, i.e. a region in the Arctic. To estimate the linkage between avalanche danger and weather conditions in this region, we utilise expert assessments of regional avalanche-danger level (ADL), the 3 km Norwegian Reanalysis (NORA3), and snow-cover information from the snow model seNorge. Random forest (RF) models are trained and optimised for a binary case and for a four-level case. The binary-case RF model exhibits a much higher overall accuracy (76 %) than the four-level case RF model (57 %), which is due to the latter model often misclassifying ADL 1 as ADL 2 and ADL 4 as ADL 3. Still, the misclassification difference is seldom larger than one ADL, and the distribution of the frequencies of the different ADLs is reproduced. The most important predictive features are related to new snow and wind accumulated and averaged over several days. The binary-case RF model is used to hindcast avalanche-day frequency (ADF) from 1970 to 2024. In this period, the spring season (March–May) shows a small increase in ADF, whereas the winter season (December–February) exhibits negative trends. Moreover, the ADF is found to be correlated with the Arctic Oscillation (AO) index especially in winter, although this correlation appears to have deteriorated in recent years. Given recent advances in skill of representing the AO in decadal prediction systems, this is an encouraging result for the predictability of future avalanche-danger tendencies in northern Norway.</p
Subsidies, Production Structure and Technical Change: A Cross-Country Comparison
No full textThe effect of subsidies on production and technical change of crop farms in France and the United Kingdom (UK) during 1980-2006 is investigated. Subsidies were not neutral on production decisions, in terms of production intensity and type. Crop farms in both countries have experienced technical progress during the period studied, higher in France. Technical progress has favoured labour and chemicals in both countries, land in France, capital in the UK, while it has disfavoured land in the UK and capital in France. Technical change has been slowed down by crop area subsidies but increased by agri-environmental subsidies in both countries.technical change, subsidies, input bias, crop farms, Agricultural and Food Policy, Production Economics, Public Economics,
The global atmospheric energy transport analysed by a wavelength-based scale separation
No full textThe atmosphere transports energy polewards by circulation cells and eddies. To the present day, there has been a knowledge gap regarding the preferred spatial scales and physical mechanisms of eddy energy transport. To fill the gap, we separate the meridional atmospheric energy transport in the ERA5 reanalysis by spatial scales and into quasi-stationary and transient flow patterns and latent and dry components.
Baroclinic instability is the major instability mechanism in the transient synoptic scales and is responsible for forming cyclones, anticyclones, and small-scale Rossby waves. At the planetary scales, circulation patterns are often induced by other mechanisms such as flow interaction with orography and land–sea heating contrasts. However, a separation between circulation patterns at the synoptic and planetary scales has yet to be established.
We find that both baroclinically induced and transient energy transport is predominantly associated with eddies at wavelengths between 2000 and 8000 km.
The maxima in both types of transport occur at wavelengths around 5000 km, in good agreement with linear baroclinic theory. Since these results are independent of latitude, we adapt the scale separation of the energy transport to be based on the wavelength instead of the previously used wavenumber. We define the synoptic transport by the wavelength band between 2000 and 8000 km.
We analyse the annual and seasonal mean in the energy transport components and their inter-annual variability. The scale-separated transport components are fairly similar in both hemispheres.
Transport by synoptic waves is the largest contributor to extra-tropical energy and moisture transport, mainly of a transient character, and is influenced little by seasonality. In contrast, transport by planetary waves depends highly on the season and has two distinct characteristics. (1) In the extra-tropical winter, planetary waves are important due to a large transport of dry energy. This planetary transport features the largest inter-annual variability of all components and is mainly quasi-stationary in the Northern Hemisphere but transient in its southern counterpart. (2) In the sub-tropical summer, quasi-stationary planetary waves are the most important transport component, mainly due to moisture transport, presumably associated with monsoons.
In contrast to transport by planetary and synoptic waves, only a negligible amount of energy is transported by mesoscale eddies (< 2000 km).</p
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