Acclimation to short-term low temperatures in two Eucalyptus globulus clones with contrasting drought resistance

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Short-term multinodal load forecasting in distribution systems using general regression neural networks

Multinodal load forecasting deals with the loads of several interest nodes in an electrical network system, which is also known as bus load forecasting. To perform this demand, it is necessary a technique that is precise, trustable and has a short-time processing. This paper proposes two methodologies based on general regression neural networks for short-term multinodal load forecasting. The first individually forecast the local loads and the second forecast the global load and individually forecast the load participation factors to estimate the local loads. To design the forecasters it wasn't necessary the previous study of the local loads. Tests were made using a New Zealand distribution subsystem and the results obtained are compatible with the ones founded in the specialized literature. © 2011 IEEE.

Endovascular Revascularization of Below-the-Knee Arteries: Prospective Short-Term Angiographic and Clinical Follow-up

PURPOSE: To evaluate arterial lesion characteristics and their impact on angiographic and clinical outcomes after endovascular below-the-knee (BTK) revascularization. MATERIALS AND METHODS: Between April 2008 and June 2009, 33 patients (mean age 74.9 years) with 34 limbs and 50 arterial segments (mean lesion length 59.3 mm) undergoing endovascular BTK revascularization agreed to undergo prospective clinical and intraarterial angiographic 6-month follow-up evaluation. Clinical indication for BTK revascularization was critical limb ischemia (CLI) in 18 patients and delayed wound healing without hemodynamic evidence of CLI and intermittent claudication (IC) in 15 patients. RESULTS: Binary restenosis was observed in 40% of treated segments at 6 months. Primary sustained clinical improvement was 82.4% and 55.9% at 3 months and 6 months. Lesion length was independently associated with binary restenosis (hazard ratio [HR] 1.013, 95% confidence interval [CI] 1.000-1.016, P = .05) and lower rates of primary sustained clinical improvement (HR 1.024, 95% CI 1.006-1.042, P = .008). CONCLUSIONS: Endovascular BTK revascularization yields clinical and angiographic benefits both for patients with IC and for patients with CLI. Although arterial lesion length adversely affects angiographic and clinical outcomes after endovascular revascularization, limb salvage rates were substantially higher compared with the comparatively low patency rates after BTK angioplasty.

Short-term vs conventional glucocorticoid therapy in acute exacerbations of chronic obstructive pulmonary disease: the REDUCE randomized clinical trial

IMPORTANCE International guidelines advocate a 7- to 14-day course of systemic glucocorticoid therapy in acute exacerbations of chronic obstructive pulmonary disease (COPD). However, the optimal dose and duration are unknown. OBJECTIVE To investigate whether a short-term (5 days) systemic glucocorticoid treatment in patients with COPD exacerbation is noninferior to conventional (14 days) treatment in clinical outcome and whether it decreases the exposure to steroids. DESIGN, SETTING, AND PATIENTS REDUCE: (Reduction in the Use of Corticosteroids in Exacerbated COPD), a randomized, noninferiority multicenter trial in 5 Swiss teaching hospitals, enrolling 314 patients presenting to the emergency department with acute COPD exacerbation, past or present smokers (≥20 pack-years) without a history of asthma, from March 2006 through February 2011. INTERVENTIONS Treatment with 40 mg of prednisone daily for either 5 or 14 days in a placebo-controlled, double-blind fashion. The predefined noninferiority criterion was an absolute increase in exacerbations of at most 15%, translating to a critical hazard ratio of 1.515 for a reference event rate of 50%. MAIN OUTCOME AND MEASURE Time to next exacerbation within 180 days. RESULTS Of 314 randomized patients, 289 (92%) of whom were admitted to the hospital, 311 were included in the intention-to-treat analysis and 296 in the per-protocol analysis. Hazard ratios for the short-term vs conventional treatment group were 0.95 (90% CI, 0.70 to 1.29; P = .006 for noninferiority) in the intention-to-treat analysis and 0.93 (90% CI, 0.68 to 1.26; P = .005 for noninferiority) in the per-protocol analysis, meeting our noninferiority criterion. In the short-term group, 56 patients (35.9%) reached the primary end point; 57 (36.8%) in the conventional group. Estimates of reexacerbation rates within 180 days were 37.2% (95% CI, 29.5% to 44.9%) in the short-term; 38.4% (95% CI, 30.6% to 46.3%) in the conventional, with a difference of -1.2% (95% CI, -12.2% to 9.8%) between the short-term and the conventional. Among patients with a reexacerbation, the median time to event was 43.5 days (interquartile range [IQR], 13 to 118) in the short-term and 29 days (IQR, 16 to 85) in the conventional. There was no difference between groups in time to death, the combined end point of exacerbation, death, or both and recovery of lung function. In the conventional group, mean cumulative prednisone dose was significantly higher (793 mg [95% CI, 710 to 876 mg] vs 379 mg [95% CI, 311 to 446 mg], P < .001), but treatment-associated adverse reactions, including hyperglycemia and hypertension, did not occur more frequently. CONCLUSIONS AND RELEVANCE In patients presenting to the emergency department with acute exacerbations of COPD, 5-day treatment with systemic glucocorticoids was noninferior to 14-day treatment with regard to reexacerbation within 6 months of follow-up but significantly reduced glucocorticoid exposure. These findings support the use of a 5-day glucocorticoid treatment in acute exacerbations of COPD. TRIAL REGISTRATION isrctn.org Identifier: ISRCTN19646069.

Short-term clinical outcomes among patients undergoing transcatheter aortic valve implantation in Switzerland: the Swiss TAVI registry

Aims: To evaluate short-term clinical outcomes following transcatheter aortic valve implantation (TAVI) using CE-mark approved devices in Switzerland. Methods and results: The Swiss TAVI registry is a national, prospective, multicentre, monitored cohort study evaluating clinical outcomes in consecutive patients undergoing TAVI at cardiovascular centres in Switzerland. From February 2011 to March 2013, a total of 697 patients underwent TAVI for native aortic valve stenosis (98.1%), degenerative aortic bioprosthesis (1.6%) or severe aortic regurgitation (0.3%). Patients were elderly (82.4±6 years), 52% were females, and the majority highly symptomatic (73.1% NYHA III/IV). Patients with severe aortic stenosis (mean gradient 44.8±17 mmHg, aortic valve area 0.7±0.3 cm2) were either deemed inoperable or at high risk for conventional surgery (STS 8.2%±7). The transfemoral access was the most frequently used (79.1%), followed by transapical (18.1%), direct aortic (1.7%) and subclavian access (1.1%). At 30 days, rates of all-cause mortality, cerebrovascular events and myocardial infarction were 4.8%, 3.3% and 0.4%, respectively. The most frequently observed adverse events were access-related complications (11.8%), permanent pacemaker implantation (20.5%) and bleeding complications (16.6%). The Swiss TAVI registry is registered at ClinicalTrials.gov (NCT01368250). Conclusions: The Swiss TAVI registry is a national cohort study evaluating consecutive TAVI procedures in Switzerland. This first outcome report provides favourable short-term clinical outcomes in unselected TAVI patients.

Extraversion and short-term memory for chromatic stimuli: an event-related potential analysis.

The present study investigated extraversion-related individual differences in visual short-term memory (VSTM) functioning. Event related potentials were recorded from 50 introverts and 50 extraverts while they performed a VSTM task based on a color-change detection paradigm with three different set sizes. Although introverts and extraverts showed almost identical hit rates and reaction times, introverts displayed larger N1 amplitudes than extraverts independent of color change or set size. Extraverts also showed larger P3 amplitudes compared to introverts when there was a color change, whereas no extraversion-related difference in P3 amplitude was found in the no-change condition. Our findings provided the first experimental evidence that introverts' greater reactivity to punctuate physical stimulation, as indicated by larger N1 amplitude, also holds for complex visual stimulus patterns. Furthermore, P3 amplitude in the change condition was larger for extraverts than introverts suggesting higher sensitivity to context change. Finally, there were no extraversion-related differences in P3 amplitude dependent on set size. This latter finding does not support the resource allocation explanation as a source of differences between introverts and extraverts.

Adult acclimation to combined temperature and pH stressors significantly enhances reproductive outcomes compared to short-term exposures

This study examined the effects of long-term culture under altered conditions on the Antarctic sea urchin, Sterechinus neumayeri. Sterechinus neumayeri was cultured under the combined environmental stressors of lowered pH (-0.3 and -0.5 pH units) and increased temperature (+2 °C) for 2 years. This time-scale covered two full reproductive cycles in this species and analyses included studies on both adult metabolism and larval development. Adults took at least 6-8 months to acclimate to the altered conditions, but beyond this, there was no detectable effect of temperature or pH. Animals were spawned after 6 and 17 months exposure to altered conditions, with markedly different outcomes. At 6 months, the percentage hatching and larval survival rates were greatest in the animals kept at 0 °C under current pH conditions, whilst those under lowered pH and +2 °C performed significantly less well. After 17 months, performance was not significantly different across treatments, including controls. However, under the altered conditions urchins produced larger eggs compared with control animals. These data show that under long-term culture adult S. neumayeri appear to acclimate their metabolic and reproductive physiology to the combined stressors of altered pH and increased temperature, with relatively little measureable effect. They also emphasize the importance of long-term studies in evaluating effects of altered pH, particularly in slow developing marine species with long gonad maturation times, as the effects of altered conditions cannot be accurately evaluated unless gonads have fully matured under the new conditions.

Strong shift from HCO3- to CO2 uptake in Emiliania huxleyi with acidification: new approach unravels acclimation versus short-term pH effects

Effects of ocean acidification on Emiliania huxleyi strain RCC 1216 (calcifying, diploid life-cycle stage) and RCC 1217 (non-calcifying, haploid life-cycle stage) were investigated by measuring growth, elemental composition, and production rates under different pCO2 levels (380 and 950 µatm). In these differently acclimated cells, the photosynthetic carbon source was assessed by a (14)C disequilibrium assay, conducted over a range of ecologically relevant pH values (7.9-8.7). In agreement with previous studies, we observed decreased calcification and stimulated biomass production in diploid cells under high pCO2, but no CO2-dependent changes in biomass production for haploid cells. In both life-cycle stages, the relative contributions of CO2 and HCO3 (-) uptake depended strongly on the assay pH. At pH values =< 8.1, cells preferentially used CO2 (>= 90 % CO2), whereas at pH values >= 8.3, cells progressively increased the fraction of HCO3 (-) uptake (~45 % CO2 at pH 8.7 in diploid cells; ~55 % CO2 at pH 8.5 in haploid cells). In contrast to the short-term effect of the assay pH, the pCO2 acclimation history had no significant effect on the carbon uptake behavior. A numerical sensitivity study confirmed that the pH-modification in the (14)C disequilibrium method yields reliable results, provided that model parameters (e.g., pH, temperature) are kept within typical measurement uncertainties. Our results demonstrate a high plasticity of E. huxleyi to rapidly adjust carbon acquisition to the external carbon supply and/or pH, and provide an explanation for the paradoxical observation of high CO2 sensitivity despite the apparently high HCO3 (-) usage seen in previous studies.

Photophysiological responses of Southern Ocean phytoplankton to changes in CO2 concentrations: Short-term versus acclimation effects

The present study examines how different pCO2 acclimations affect the CO2- and light-dependence of photophysiological processes and O2 fluxes in four Southern Ocean (SO) key phytoplankton species. We grew Chaetoceros debilis (Cleve), Pseudo-nitzschia subcurvata (Hasle), Fragilariopsis kerguelensis (O'Meara) and Phaeocystis antarctica (Karsten) under low (160 µatm) and high (1000 ?atm) pCO2. The CO2- and light-dependence of fluorescence parameters of photosystem II (PSII) were determined by means of a fluorescence induction relaxation system (FIRe). In all tested species, nonphotochemical quenching (NPQ) is the primary photoprotection strategy in response to short-term exposure to high light or low CO2 concentrations. In C. debilis and P. subcurvata, PSII connectivity (p) and functional absorption cross-sections of PSII in ambient light (sigma PSII') also contributed to photoprotection while changes in re-oxidation times of Qa acceptor (tQa) were more significant in F. kerguelensis. The latter was also the only species being responsive to high acclimation pCO2, as these cells had enhanced relative electron transport rates (rETRs) and sigma PSII' while tQa and p were reduced under short-term exposure to high irradiance. Low CO2-acclimated cells of F. kerguelensis and all pCO2 acclimations of C. debilis and P. subcurvata showed dynamic photoinhibition with increasing irradiance. To test for the role and presence of the Mehler reaction in C. debilis and P. subcurvata, the light-dependence of O2 fluxes was estimated using membrane inlet mass spectrometry (MIMS). Our results show that the Mehler reaction is absent in both species under the tested conditions. We also observed that dark respiration was strongly reduced under high pCO2 in C. debilis while it remained unaltered in P. subcurvata. Our study revealed species-specific differences in the photophysiological responses to pCO2, both on the acclimation as well as the short-term level.

Combined effects of short-term ocean acidification and heat shock in a benthic copepod Tigriopus japonicus Mori

Warming of the world's oceans is predicted to have many negative effects on organisms as they have optimal thermal windows. In coastal waters, however, both temperatures and pCO2 (pH) exhibit diel variations, and biological performances are likely to be modulated by physical and chemical environmental changes. To understand how coastal zooplankton respond to the combined impacts of heat shock and increased pCO2, the benthic copepod Tigriopus japonicus were treated at temperatures of 24, 28, 32 and 36 °C to simulate natural coastal temperatures experienced in warming events, when acclimated in the short term to either ambient (LC, 390 µatm) or future CO2 (HC, 1000 µatm). HC and heat shock did not induce any mortality of T. japonicus, though respiration increased up to 32 °C before being depressed at 36 °C. Feeding rate peaked at 28 °C but did not differ between CO2 treatments. Expression of heat shock proteins (hsps mRNA) was positively related to temperature, with no significant differences between the CO2 concentrations. Nauplii production was not affected across all treatments. Our results demonstrate that T. japonicus responds more sensitively to heat shocks rather than to seawater acidification; however, ocean acidification may synergistically act with ocean warming to mediate the energy allocation of copepods.

Statistical models for short-term wind power ramp forecasting

La predicción de energía eólica ha desempeñado en la última década un papel fundamental en el aprovechamiento de este recurso renovable, ya que permite reducir el impacto que tiene la naturaleza fluctuante del viento en la actividad de diversos agentes implicados en su integración, tales como el operador del sistema o los agentes del mercado eléctrico. Los altos niveles de penetración eólica alcanzados recientemente por algunos países han puesto de manifiesto la necesidad de mejorar las predicciones durante eventos en los que se experimenta una variación importante de la potencia generada por un parque o un conjunto de ellos en un tiempo relativamente corto (del orden de unas pocas horas). Estos eventos, conocidos como rampas, no tienen una única causa, ya que pueden estar motivados por procesos meteorológicos que se dan en muy diferentes escalas espacio-temporales, desde el paso de grandes frentes en la macroescala a procesos convectivos locales como tormentas. Además, el propio proceso de conversión del viento en energía eléctrica juega un papel relevante en la ocurrencia de rampas debido, entre otros factores, a la relación no lineal que impone la curva de potencia del aerogenerador, la desalineación de la máquina con respecto al viento y la interacción aerodinámica entre aerogeneradores. En este trabajo se aborda la aplicación de modelos estadísticos a la predicción de rampas a muy corto plazo. Además, se investiga la relación de este tipo de eventos con procesos atmosféricos en la macroescala. Los modelos se emplean para generar predicciones de punto a partir del modelado estocástico de una serie temporal de potencia generada por un parque eólico. Los horizontes de predicción considerados van de una a seis horas. Como primer paso, se ha elaborado una metodología para caracterizar rampas en series temporales. La denominada función-rampa está basada en la transformada wavelet y proporciona un índice en cada paso temporal. Este índice caracteriza la intensidad de rampa en base a los gradientes de potencia experimentados en un rango determinado de escalas temporales. Se han implementado tres tipos de modelos predictivos de cara a evaluar el papel que juega la complejidad de un modelo en su desempeño: modelos lineales autorregresivos (AR), modelos de coeficientes variables (VCMs) y modelos basado en redes neuronales (ANNs). Los modelos se han entrenado en base a la minimización del error cuadrático medio y la configuración de cada uno de ellos se ha determinado mediante validación cruzada. De cara a analizar la contribución del estado macroescalar de la atmósfera en la predicción de rampas, se ha propuesto una metodología que permite extraer, a partir de las salidas de modelos meteorológicos, información relevante para explicar la ocurrencia de estos eventos. La metodología se basa en el análisis de componentes principales (PCA) para la síntesis de la datos de la atmósfera y en el uso de la información mutua (MI) para estimar la dependencia no lineal entre dos señales. Esta metodología se ha aplicado a datos de reanálisis generados con un modelo de circulación general (GCM) de cara a generar variables exógenas que posteriormente se han introducido en los modelos predictivos. Los casos de estudio considerados corresponden a dos parques eólicos ubicados en España. Los resultados muestran que el modelado de la serie de potencias permitió una mejora notable con respecto al modelo predictivo de referencia (la persistencia) y que al añadir información de la macroescala se obtuvieron mejoras adicionales del mismo orden. Estas mejoras resultaron mayores para el caso de rampas de bajada. Los resultados también indican distintos grados de conexión entre la macroescala y la ocurrencia de rampas en los dos parques considerados. Abstract One of the main drawbacks of wind energy is that it exhibits intermittent generation greatly depending on environmental conditions. Wind power forecasting has proven to be an effective tool for facilitating wind power integration from both the technical and the economical perspective. Indeed, system operators and energy traders benefit from the use of forecasting techniques, because the reduction of the inherent uncertainty of wind power allows them the adoption of optimal decisions. Wind power integration imposes new challenges as higher wind penetration levels are attained. Wind power ramp forecasting is an example of such a recent topic of interest. The term ramp makes reference to a large and rapid variation (1-4 hours) observed in the wind power output of a wind farm or portfolio. Ramp events can be motivated by a broad number of meteorological processes that occur at different time/spatial scales, from the passage of large-scale frontal systems to local processes such as thunderstorms and thermally-driven flows. Ramp events may also be conditioned by features related to the wind-to-power conversion process, such as yaw misalignment, the wind turbine shut-down and the aerodynamic interaction between wind turbines of a wind farm (wake effect). This work is devoted to wind power ramp forecasting, with special focus on the connection between the global scale and ramp events observed at the wind farm level. The framework of this study is the point-forecasting approach. Time series based models were implemented for very short-term prediction, this being characterised by prediction horizons up to six hours ahead. As a first step, a methodology to characterise ramps within a wind power time series was proposed. The so-called ramp function is based on the wavelet transform and it provides a continuous index related to the ramp intensity at each time step. The underlying idea is that ramps are characterised by high power output gradients evaluated under different time scales. A number of state-of-the-art time series based models were considered, namely linear autoregressive (AR) models, varying-coefficient models (VCMs) and artificial neural networks (ANNs). This allowed us to gain insights into how the complexity of the model contributes to the accuracy of the wind power time series modelling. The models were trained in base of a mean squared error criterion and the final set-up of each model was determined through cross-validation techniques. In order to investigate the contribution of the global scale into wind power ramp forecasting, a methodological proposal to identify features in atmospheric raw data that are relevant for explaining wind power ramp events was presented. The proposed methodology is based on two techniques: principal component analysis (PCA) for atmospheric data compression and mutual information (MI) for assessing non-linear dependence between variables. The methodology was applied to reanalysis data generated with a general circulation model (GCM). This allowed for the elaboration of explanatory variables meaningful for ramp forecasting that were utilized as exogenous variables by the forecasting models. The study covered two wind farms located in Spain. All the models outperformed the reference model (the persistence) during both ramp and non-ramp situations. Adding atmospheric information had a noticeable impact on the forecasting performance, specially during ramp-down events. Results also suggested different levels of connection between the ramp occurrence at the wind farm level and the global scale.

Short-term correction of factor VIII deficiency in a murine model of hemophilia A after delivery of adenovirus murine factor VIII in utero

Development of in utero gene transfer approaches may provide therapies for genetic disorders with perinatal morbidity. In hemophilia A, prenatal and postnatal bleeding may be catastrophic, and modest increments in factor VIII (FVIII) activity are therapeutic. We performed transuterine i.p. gene transfer at day 15 of gestation in a murine model of hemophilia A. Normal, carrier (XHX), and FVIII-deficient (XHY and XHXH) fetuses injected with adenoviral vectors carrying luciferase or β-galactosidase reporter genes showed high-level gene expression with 91% fetal survival. The live-born rates of normal and FVIII-deficient animals injected in utero with adenovirus murine FVIII (3.3 × 105 plaque-forming units) was 87%. FVIII activity in plasma was 50.7 ± 10.5% of normal levels at day 2 of life, 7.2 ± 2.2% by day 15 of life, and no longer detectable at day 21 of life in hemophilic animals. Injection of higher doses of murine FVIII adenovirus at embryonic day 15 produced supranormal levels of FVIII activity in the neonatal period. PCR analysis identified viral genomes primarily in the liver, intestine, and spleen, although adenoviral DNA was detected in distal tissues when higher doses of adenovirus were administered. These studies show that transuterine i.p. injection of adenoviral vectors produces therapeutic levels of circulating FVIII throughout the neonatal period. The future development of efficient and persisting vectors that produce long-term gene expression may allow for in utero correction of genetic diseases originating in the fetal liver, hematopoietic stem cells, as well as other tissues.

Distinct short-term plasticity at two excitatory synapses in the hippocampus

A single mossy fiber input contains several release sites and is located on the proximal portion of the apical dendrite of CA3 neurons. It is, therefore, well suited to exert a strong influence on pyramidal cell excitability. Accordingly, the mossy fiber synapse has been referred to as a detonator or teacher synapse in autoassociative network models of the hippocampus. The very low firing rates of granule cells [Jung, M. W. & McNaughton, B. L. (1993) Hippocampus 3, 165–182], which give rise to the mossy fibers, raise the question of how the mossy fiber synapse temporally integrates synaptic activity. We have therefore addressed the frequency dependence of mossy fiber transmission and compared it to associational/commissural synapses in the CA3 region of the hippocampus. Paired pulse facilitation had a similar time course, but was 2-fold greater for mossy fiber synapses. Frequency facilitation, during which repetitive stimulation causes a reversible growth in synaptic transmission, was markedly different at the two synapses. At associational/commissural synapses facilitation occurred only at frequencies greater than once every 10 s and reached a magnitude of about 125% of control. At mossy fiber synapses, facilitation occurred at frequencies as low as once every 40 s and reached a magnitude of 6-fold. Frequency facilitation was dependent on a rise in intraterminal Ca2+ and activation of Ca2+/calmodulin-dependent kinase II, and was greatly reduced at synapses expressing mossy fiber long-term potentiation. These results indicate that the mossy fiber synapse is able to integrate granule cell spiking activity over a broad range of frequencies, and this dynamic range is substantially reduced by long-term potentiation.

Relationships of dehydroepiandrosterone sulfate in the elderly with functional, psychological, and mental status, and short-term mortality: A French community-based study

In human beings of both sexes, dehydroepiandrosterone sulfate (DHEAS) circulating in blood is mostly an adrenally secreted steroid whose serum concentration (in the micromolar range and 30–50% higher in men than in women) decreases with age, toward ≈20–10% of its value in young adults during the 8th and 9th decades. The mechanism of action of DHEA and DHEAS is poorly known and may include partial transformation into sex steroids, increase of bioavailable insulin-like growth factor I, and effects on neurotransmitter receptors. Whether there is a cause-to-effect relationship between the decreasing levels of DHEAS with age and physiological and pathological manifestations of aging is still undecided, but this is of obvious theoretical and practical interest in view of the easy restoration by DHEA administration. Here we report on 622 subjects over 65 years of age, studied for the 4 years since DHEAS baseline values had been obtained, in the frame of the PAQUID program, analyzing the functional, psychological, and mental status of a community-based population in the south-west of France. We confirm the continuing decrease of DHEAS serum concentration with age, more in men than in women, even if men retain higher levels. Significantly lower values of baseline DHEAS were recorded in women in cases of functional limitation (Instrumental Activities of Daily Living), confinement, dyspnea, depressive symptomatology, poor subjective perception of health and life satisfaction, and usage of various medications. In men, there was a trend for the same correlations, even though not statistically significant in most categories. No differences in DHEAS levels were found in cases of incident dementia in the following 4 years. In men (but not in women), lower DHEAS was significantly associated with increased short-term mortality at 2 and 4 years after baseline measurement. These results, statistically established by taking into account corrections for age, sex, and health indicators, suggest the need for further careful trials of the administration of replacement doses of DHEA in aging humans. Indeed, the first noted results of such “treatment” are consistent with correlations observed here between functional and psychological status and endogenous steroid serum concentrations.

Did quantitative easing affect interest rates outside the US? New evidence based on interest rate differentials. CEPS Working Document No. 416/January 2016

This paper explores the effects of non-standard monetary policies on international yield relationships. Based on a descriptive analysis of international long-term yields, we find evidence that long-term rates followed a global downward trend prior to as well as during the financial crisis. Comparing interest rate developments in the US and the eurozone, it is difficult to detect a distinct impact of the first round of the Fed’s quantitative easing programme (QE1) on US interest rates for which the global environment – the global downward trend in interest rates – does not account. Motivated by these findings, we analyse the impact of the Fed’s QE1 programme on the stability of the US-euro long-term interest rate relationship by using a CVAR (cointegrated vector autoregressive) model and, in particular, recursive estimation methods. Using data gathered between 2002 and 2014, we find limited evidence that QE1 caused the break-up or destabilised the transatlantic interest rate relationship. Taking global interest rate developments into account, we thus find no significant evidence that QE had any independent, distinct impact on US interest rates.