176 research outputs found
Natura 2000 and the regulation of agricultural ammonia emissions
This article provides a comparative analysis of the regulation of ammonia emissions, primarily from livestock installations, in Denmark, Germany and the Netherlands. It discusses the challenges of regulating agricultural ammonia emissions in view of the rulings of the Court of Justice of the European Union (cjeu) on Art. 6(3) of the Habitats Directive. It is argued that the need to ensure certainty concerning the absence of significant effects on Natura 2000 sites is challenged by the uncertainties regarding both the state of individual habitat types and the potential impact of individual projects. A more integrated or programmatic approach may provide an alternative approach to individual assessments, but it is necessary to ensure that additional loads from new or enlarged livestock installations are permitted in areas with high ammonia loads only where it is certain that a programmatic approach will ensure that there are no harmful effects. This might be an almost impossible task
Crossover from adiabatic to sudden interaction quenches in the Hubbard model: Prethermalization and nonequilibrium dynamics
The recent experimental implementation of condensed matter models in optical
lattices has motivated research on their nonequilibrium behavior. Predictions
on the dynamics of superconductors following a sudden quench of the pairing
interaction have been made based on the effective BCS Hamiltonian; however,
their experimental verification requires the preparation of a suitable excited
state of the Hubbard model along a twofold constraint: (i) a sufficiently
nonadiabatic ramping scheme is essential to excite the nonequilibrium dynamics,
and (ii) overheating beyond the critical temperature of superconductivity must
be avoided. For commonly discussed interaction ramps there is no clear
separation of the corresponding energy scales. Here we show that the matching
of both conditions is simplified by the intrinsic relaxation behavior of
ultracold fermionic systems: For the particular example of a linear ramp we
examine the transient regime of prethermalization [M. Moeckel and S. Kehrein,
Phys. Rev. Lett. 100, 175702 (2008)] under the crossover from sudden to
adiabatic switching using Keldysh perturbation theory. A real-time analysis of
the momentum distribution exhibits a temporal separation of an early energy
relaxation and its later thermalization by scattering events. For long but
finite ramping times this separation can be large. In the prethermalization
regime the momentum distribution resembles a zero temperature Fermi liquid as
the energy inserted by the ramp remains located in high energy modes. Thus
ultracold fermions prove robust to heating which simplifies the observation of
nonequilibrium BCS dynamics in optical lattices.Comment: 27 pages, 8 figures Second version with small modifications in
section
Selection Criteria for Drug-Eluting Versus Bare-Metal Stents and the Impact of Routine Angiographic Follow-Up 2-Year Insights From the HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) Trial
ObjectivesWe sought to identify patients with ST-segment elevation myocardial infarction most likely to benefit from drug-eluting stents (DES), and to evaluate the impact of routine angiographic follow-up on the apparent differences between stent types.BackgroundDES might have greatest utility in patients who would benefit most from their antirestenotic properties.MethodsWe randomly assigned 3,006 patients with ST-segment elevation myocardial infarction to paclitaxel-eluting stents (PES) or to bare-metal stents (BMS). Events were assessed at 12 months and 24 months, with a subset undergoing routine angiographic follow-up at 13 months. Using well-known risk factors for restenosis and target lesion revascularization (TLR), risk groups were formed to examine the absolute differences between PES and BMS.ResultsCompared with BMS, PES reduced TLR at 12 months from 7.4% to 4.5% (p = 0.003). Insulin-treated diabetes mellitus (hazard ratio: 3.12), reference vessel diameter ≤3.0 mm (hazard ratio: 2.89), and lesion length ≥30 mm (hazard ratio: 2.49) were independent predictors of 12-month TLR after BMS. In patients with 2 or 3 of these baseline risk factors, PES compared with BMS markedly reduced 12-month TLR (19.8% vs. 8.1%, p = 0.003). In patients with 1 of these risk factors, the 12-month rates of TLR were modestly reduced by PES (7.3% vs. 4.3%, p = 0.02). The 12-month TLR rates were low and similar for both stents in patients with 0 risk factors (3.3% vs. 3.2%, p = 0.93). Routine 13-month angiographic follow-up resulted in a marked increase in TLR procedures (more so with BMS) so that the absolute incremental benefit of PES compared with BMS doubled from 2.9% at 12 months to 6.0% at 24 months, a difference evident in all risk strata.ConclusionsPatients at high risk for TLR after BMS in ST-segment elevation myocardial infarction for whom DES are of greatest benefit may be identified. Conversely, DES may be of less clinical benefit for patients at lower risk for TLR after BMS. Routine angiographic follow-up increases the perceived clinical benefits of DES, and must be avoided to accurately estimate absolute treatment effects. (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction [HORIZONS-AMI]; NCT00433966
Early diagnosis of acute coronary syndrome.
The diagnostic evaluation of acute chest pain has been augmented in recent years by advances in the sensitivity and precision of cardiac troponin assays, new biomarkers, improvements in imaging modalities, and release of new clinical decision algorithms. This progress has enabled physicians to diagnose or rule-out acute myocardial infarction earlier after the initial patient presentation, usually in emergency department settings, which may facilitate prompt initiation of evidence-based treatments, investigation of alternative diagnoses for chest pain, or discharge, and permit better utilization of healthcare resources. A non-trivial proportion of patients fall in an indeterminate category according to rule-out algorithms, and minimal evidence-based guidance exists for the optimal evaluation, monitoring, and treatment of these patients. The Cardiovascular Round Table of the ESC proposes approaches for the optimal application of early strategies in clinical practice to improve patient care following the review of recent advances in the early diagnosis of acute coronary syndrome. The following specific 'indeterminate' patient categories were considered: (i) patients with symptoms and high-sensitivity cardiac troponin 99th percentile but without dynamic change; and (iv) patients with symptoms and high-sensitivity troponin >99th percentile and dynamic change but without coronary plaque rupture/erosion/dissection. Definitive evidence is currently lacking to manage these patients whose early diagnosis is 'indeterminate' and these areas of uncertainty should be assigned a high priority for research
Use of procalcitonin for the diagnosis of pneumonia in patients presenting with a chief complaint of dyspnoea: results from the BACH (Biomarkers in Acute Heart Failure) trial
Biomarkers have proven their ability in the evaluation of cardiopulmonary diseases.We investigated the utility of concentrations
of the biomarker procalcitonin (PCT) alone and with clinical variables for the diagnosis of pneumonia in
patients presenting to emergency departments (EDs) with a chief complaint of shortness of breath.
The BACH trial was a prospective, international, study of 1641 patients presenting to EDs with dyspnoea. Blood
samples were analysed for PCT and other biomarkers. Relevant clinical data were also captured. Patient outcomes
were assessed at 90 days. The diagnosis of pneumonia was made using strictly validated guidelines. A model using
PCT was more accurate [area under the curve (AUC) 72.3%] than any other individual clinical variable for the diagnosis
of pneumonia in all patients, in those with obstructive lung disease, and in those with acute heart failure (AHF).
Combining physician estimates of the probability of pneumonia with PCT values increased the accuracy to .86% for
the diagnosis of pneumonia in all patients. Patients with a diagnosis of AHF and an elevated PCT concentration
(.0.21 ng/mL) had a worse outcome if not treated with antibiotics (P ¼ 0.046), while patients with low PCT
values (,0.05 ng/mL) had a better outcome if they did not receive antibiotic therapy (P ¼ 0.049).
Procalcitonin may aid in the diagnosis of pneumonia, particularly in cases with high diagnostic uncertainty. Importantly,
PCT may aid in the decision to administer antibiotic therapy to patients presenting with AHF in which clinical uncertainty
exists regarding a superimposed bacterial infection
Photonic spectral density of coupled microwave cavities
We study a pair of anharmonic microwave cavities that is connected by an
optical fiber. The photonic spectral density characterizes the evolution of the
coupled cavities after the system has been prepared in a Fock or N00N state. We
evaluate the photonic spectral density within the recursive projection method
and find that the anharmonicity has no substantial effect on the spectral
properties. In all cases the photonic spectral density has a Gaussian envelope
for large photon numbers.Comment: 8 pages, 6 figure
Coma of unknown origin in the emergency department: implementation of an in-house management routine
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