The asymptotic structure of nearly unstable non-negative integer-valued AR(1) models

This paper considers non-negative integer-valued autoregressive processes where the autoregression parameter is close to unity. We consider the asymptotics of this `near unit root' situation. The local asymptotic structure of the likelihood ratios of the model is obtained, showing that the limit experiment is Poissonian. To illustrate the statistical consequences we discuss efficient estimation of the autoregression parameter and efficient testing for a unit root.Comment: Published in at http://dx.doi.org/10.3150/08-BEJ153 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

Efficient Estimation in Semiparametric Time Series: the ACD Model

In this paper we consider efficient estimation in semiparametric ACD models. We consider a suite of model specifications that impose less and less structure. We calculate the corresponding efficiency bounds, discuss the construction of efficient estimators in each case, and study tvide a simulation study that shows the practical gain from using the proposed semiparametric procedures. We find that, although one does not gain as much as theory suggests, these semiparametric procedures definitely outperform more classical procedures. We apply the procedures to model semiparametrically durations observed on the Paris Bourse for the Alcatel stock in July and August 1996.

Seasonal Biotic Processes Vary the Carbon Turnover by Up To One Order of Magnitude in Wetlands

Soil Organic Carbon (SOC) turnover t in wetlands and the corresponding governing processes are still poorly represented in numerical models. t is a proxy to the carbon storage potential in each SOC pool and C fluxes within the whole ecosystem; however, it has not been comprehensively quantified in wetlands globally. Here, we quantify the turnover time t of various SOC pools and the governing biotic and abiotic processes in global wetlands using a comprehensively tested process-based biogeochemical model. Globally, we found that t ranges between 1 and 1,000 years and is controlled by anaerobic (in 78% of global wetlands area) and aerobic (15%) respiration, and by abiotic destabilization from soil minerals (5%). t in the remaining 2% of wetlands is controlled by denitrification, sulfur reduction, and leaching below the subsoil. t can vary by up to one order of magnitude in temperate, continental, and polar regions due to seasonal temperature and can shift from being aerobically controlled to anaerobically controlled. Our findings of seasonal variability in SOC turnover suggest that wetlands are susceptible to climate-induced shifts in seasonality, thus requiring better accounting of seasonal fluctuations at geographic scales to estimate C exchanges between land and atmosphere

Use of sepsis-related diagnostic criteria in primary care:a survey among general practitioners

BACKGROUND: Use of sepsis-criteria in hospital settings is effective in realizing early recognition, adequate treatment and reduction of sepsis-associated morbidity and mortality. Whether general practitioners (GPs) use these diagnostic criteria is unknown. OBJECTIVE: To gauge the knowledge and use of various diagnostic criteria. To determine which parameters GPs associate with an increased likelihood of sepsis. METHODS: Two thousand five hundred and sixty GPs were invited and 229 agreed to participate in a survey, reached out to through e-mail and WhatsApp groups. The survey consisted of two parts: the first part aimed to obtain information about the GP, training and knowledge about sepsis recognition, and the second part tested specific knowledge using six realistic cases. RESULTS: Two hundred and six questionnaires, representing a response rate of 8.1%, were eligible for analysis. Gut feeling (98.1%) was the most used diagnostic method, while systemic inflammatory response syndrome (37.9%), quick Sequential Organ Failure Assessment (qSOFA) (7.8%) and UK Sepsis Trust criteria (UKSTc) (1.5%) were used by the minority of the GPs. Few of the responding GPs had heard of either the qSOFA (27.7%) or the UKSTc (11.7%). Recognition of sepsis varied greatly between GPs. GPs most strongly associated the individual signs of the qSOFA (mental status, systolic blood pressure, capillary refill time and respiratory rate) with diagnosing sepsis in the test cases. CONCLUSIONS: GPs mostly use gut feeling to diagnose sepsis and are frequently not familiar with the 'sepsis-criteria' used in hospital settings, although clinical reasoning was mostly in line with the qSOFA score. In order to improve sepsis recognition in primary care, GPs should be educated in the use of available screening tools

Towards single-electron metrology

We review the status of the understanding of single-electron transport (SET) devices with respect to their applicability in metrology. Their envisioned role as the basis of a high-precision electrical standard is outlined and is discussed in the context of other standards. The operation principles of single electron transistors, turnstiles and pumps are explained and the fundamental limits of these devices are discussed in detail. We describe the various physical mechanisms that influence the device uncertainty and review the analytical and numerical methods needed to calculate the intrinsic uncertainty and to optimise the fabrication and operation parameters. Recent experimental results are evaluated and compared with theoretical predictions. Although there are discrepancies between theory and experiments, the intrinsic uncertainty is already small enough to start preparing for the first SET-based metrological applications.Comment: 39 pages, 14 figures. Review paper to be published in International Journal of Modern Physics

Characterising standard genetic parts and establishing common principles for engineering legume and cereal roots

Plant synthetic biology and cereal engineering depends on the controlled expression of transgenes of interest. Most engineering in plant species to date has relied heavily on the use of a few, well-established constitutive promoters to achieve high levels of expression; however, the levels of transgene expression can also be influenced by the use of codon optimisation, intron-mediated enhancement and varying terminator sequences. Most of these alternative approaches for regulating transgene expression have only been tested in small-scale experiments, typically testing a single gene of interest. It is therefore difficult to interpret the relative importance of these approaches and to design engineering strategies that are likely to succeed in different plant species, particularly if engineering multi-genic traits where the expression of each transgene needs to be precisely regulated. Here we present data on the characterisation of 46 promoters and 10 terminators in Medicago truncatula, Lotus japonicus, Nicotiana benthamiana and Hordeum vulgare, as well as the effects of codon optimisation and intron-mediated enhancement on the expression of two transgenes in H. vulgare. We have identified a core set of promoters and terminators of relevance to researchers engineering novel traits in plant roots. In addition, we have shown that combining codon optimisation and intron-mediated enhancement increases transgene expression and protein levels in barley. Based on our study, we recommend a core set of promoters and terminators for broad use, and also propose a general set of principles and guidelines for those engineering cereal species

Witterungsextreme und ihre Bedeutung für die jährlichen Ertragsabweichungen von Winterweize

KlimafolgenFür die Landwirtschaft stellen Witterungsereignisse mit signifikanten Abweichungen von langjährigen Mittel eine große Herausforderung dar. Witterungsextreme wie Starkregen, Hitzeperioden während kritischer phänologischer Phasen wie beispielsweise der Blüte oder längere niederschlagsfreie Zeiten haben oftmals direkte Auswirkungen auf den Ertrag und die Qualität der Ernteprodukte. Durch den Klimawandel werden zudem die Wiederkehr von Extremereignissen und die Intensität von Witterungsereignissen beeinflusst. Die Bedeutung der Witterungsextreme für die jährlichen Ertragsschwankungen von Winterweizen wurde durch die Auswertung der Langzeitversuche des JKI in Dahnsdorf, Brandenburg untersucht. Die Klimadaten entstammen der Wetterstation auf dem Versuchsfeld und fehlende Daten sind durch Interpolation von umliegenden Klimastationen auf diesen Standort für die Zeit von 1993-2013 erzeugt worden. Während des Untersuchungszeitraums betrug die jährliche Durchschnittstemperatur 9.6°C und der Jahresniederschlag lag bei 587 mm. Die Anzahl aufeinanderfolgender Tage ohne Niederschlag (NCDWP) von April-September und die Temperatur >25°C (NHD) zur Blüte von Winterweizen im Zeitraum vom 1.-21.Juni in Kombination mit unterschiedlichen Pflanzenschutzstrategien wurde hinsichtlich der Bedeutung für die jährlichen Ertragsschwankungen analysiert. Sowohl bei den NCDWP als auch bei den NHD konnte für den Betrachtungszeitraum für die Werte oberhalb des 80%-igen Perzentils eine leichte Zunahme beider Extrema für diesen Standort gefunden werden (Zunahme von 5 auf 6 bei NHD und 14 auf 15 bei NCDWP). Eine Regressionsanalyse für den Zeitraum von 1996-2007 ergab für beide Extrema ertragsrelevante Auswirkungen auf die jährlichen Ertragsschwankungen. Hierbei zeigten die NHD eine deutlich stärkere ertragsrelevante Auswirkung als die NCDWP bei Winterweizen, abhängig von den jeweiligen Pflanzenschutzstrategien

Identifying governance challenges in ecosystem services management – Conceptual considerations and comparison of global forest cases

Ecosystems around the world generate a wide range of services. Often, there are trade-offs in ecosystem service provision. Managing such trade-offs requires governance of interdependent action situations. We distinguished between (1) enhancing action situations where beneficiaries create, maintain, or improve an ESS and (2) appropriation action situations where actors subtract from a flow of ESS. We classified ESSs in order to identify focal action situations and link them to ESS governance types which are likely to strengthen sustainable ecosystem management. The classification is applied to six forest cases in Asia, Africa and Latin America. Our results confirm that ecosystem management, which more strongly supports the provision of public goods and common pool resources, is often under strong pressure to be transformed into systems that mainly provide private goods. This can be partly explained by incentive constellations in the action situations of public goods and common pool resources. Therefore, governance has to be adapted to specific ESSs. ESS governance needs to identify institutions which best fit to different ESSs and to harmonize them for all the ESSs provided by the system. Our approach helps to understand why institutions fail or succeed in maintaining ESSs