Two key parameters for the El Niño continuum: zonal wind anomalies and Western Pacific subsurface potential temperature

This is the author accepted manuscript. The final version is available via Springer at http://link.springer.com/article/10.1007%2Fs00382-015-2550-0.Different types of El Niño (EN) events have recently been discussed. Based on NCEP-NOAA reanalysis data this analysis explores a number of key parameters that cause a range of EN types over the period 1980-2013. EN events are divided into three types depending on the spatial and temporal evolution of the sea surface temperature anomalies (SSTA): Central Pacific (CPEN), Eastern Pacific (EPEN), and Hybrid (HBEN). We find that EN is a continuous spectrum of events with CPEN and EPEN as the end members. This spectrum mainly depends on two key parameters: the 130ºE-160ºE Western Pacific 5m-250m subsurface oceanic potential temperature anomaly (PTA) about one year before the EN peak (typically January and February), and the 140ºE-160ºW cumulative zonal wind anomaly (ZWA) between onset and peak of the EN event. Using these two parameters, about 70% of the total variance of the maximum SSTA realised in different Niño regions can already be explained up to six months before the maximum SSTA occurs. This offers a rather simple potential for ENSO prediction

Observational constraints on the tropospheric and near-surface winter signature of the Northern Hemisphere stratospheric polar vortex

A composite analysis of Northern Hemisphere’s mid-winter tropospheric anomalies under the conditions of strong and weak stratospheric polar vortex was performed on NCEP/NCAR reanalysis data from 1948 to 2013 considering, as additional grouping criteria, the coincidental states of major seasonally relevant climate phenomena, such as El Niño-Southern Oscillation (ENSO), Quasi Biennial Oscillation and strong volcanic eruptions. The analysis reveals that samples of strong polar vortex nearly exclusively occur during cold ENSO states, while a weak polar vortex is observed for both cold and warm ENSO. The strongest tropospheric and near-surface anomalies are found for warm ENSO and weak polar vortex conditions, suggesting that internal tropospheric circulation anomalies related to warm ENSO constructively superpose on dynamical effects from the stratosphere. Additionally, substantial differences are found between the continental winter warming patterns under strong polar vortex conditions in volcanically-disturbed and volcanically-undisturbed winters. However, the small-size samples obtained from the multi-compositing prevent conclusive statements about typical patterns, dominating effects and mechanisms of stratosphere-troposphere interaction on the seasonal time scale based on observational/reanalysis data alone. Hence, our analysis demonstrates that patterns derived from observational/reanalysis time series need to be taken with caution as they not always provide sufficiently robust constraints to the inferred mechanisms implicated with stratospheric polar vortex variability and its tropospheric and near-surface signature. Notwithstanding this argument, we propose a limited set of mechanisms that together may explain a relevant part of observed climate variability. These may serve to define future numerical model experiments minimizing the sample biases and, thus, improving process understanding.This work was supported by the Federal Ministry for Education and Research in Germany (BMBF) through the research program “MiKlip” (FKZ:01LP1158A(DZ):/01LP1130A(CT,MB)).This is the accepted version of an article originally published in Climate Dynamics. The final publication is available at Springer via http://dx.doi.org/10.1007/s00382-014-2101-0

ENSO forecasts near the spring predictability barrier and possible reasons for the recently reduced predictability

A cross-validated statistical model has been developed to produce hindcasts for the 1980-2016 Nov-Dec-Jan (NDJ, assumed El Niño peak) mean Niño3.4 sea surface temperature anomalies (SSTA). A linear combination of two parameters is sufficient to successfully predict the peak SSTA: (1) the 130oE-180o, 5oN-5oS, 5m-250m oceanic potential temperature anomalies in February, and (2) the 140oE-160oW, 5oN-5oS cumulative zonal wind anomalies (ZWA), integrated from November (one year before) up to the prediction month. Our model is simple but comparable to, or even outperforms, many NOAA Climate Prediction Centre's statistical models during the boreal spring predictability barrier. In contrast to most statistical models, the predictand Niño3.4 SSTA is not used as a predictor. The explained variance between observed and predicted NDJ Niño3.4 SSTA at a lead-time of 8 months is 57% using five years for cross-validation, 63% in full hindcast mode. Predictive skill is lower after 2000 when the mean climate state is more La Niña-like due to stronger equatorial easterly ZWA. Strengthened Pacific subtropical highs are observed, with weaker westerly ZWA that emerge at a later time during El Niño. The Western Pacific is more recharged, with stronger upwelling over the Eastern Pacific. The resulting strong zonal subsurface temperature gradient provides a high potential for Kelvin waves being triggered without strong westerly ZWA. However, the persistent easterly ZWA lead to more Central Pacific-like El Niños. These are more difficult to predict because the contribution of the thermocline feedback is reduced. Overall, we find that the importance of the recharge state for ENSO prediction has increased after 2000, contradicting some previous studies.Partial funding for this research was provided by the Engineering and Physical Sciences Research Council (EPSRC) as part of the Low Carbon Climate-Responsive Heating and Cooling of Cities (LoHCool) project (EP/N009797/1). Andy W.-C. Lai would also like to acknowledge the support from James Lai, Grace Chang, and Joey Cheng

High-resolution modelling of interactions between soil moisture and convective development in a mountain enclosed Tibetan Basin

Abstract. The Tibetan Plateau plays a significant role in atmospheric circulation and the Asian monsoon system. Turbulent surface fluxes and the evolution of boundary-layer clouds to deep and moist convection provide a feedback system that modifies the plateau's surface energy balance on scales that are currently unresolved in mesoscale models. This work analyses the land surface's role and specifically the influence of soil moisture on the triggering of convection at a cross section of the Nam Co Lake basin, 150 km north of Lhasa using a cloud-resolving atmospheric model with a fully coupled surface. The modelled turbulent fluxes and development of convection compare reasonably well with the observed weather. The simulations span Bowen ratios of 0.5 to 2.5. It is found that convective development is the strongest at intermediate soil moisture. Dry cases with soils close to the permanent wilting point are moisture limited in convective development, while convection in wet soil moisture cases is limited by cloud cover reducing incoming solar radiation and sensible heat fluxes, which has a strong impact on the surface energy balance. This study also shows that local development of convection is an important mechanism for the upward transport of water vapour, which originates from the lake basin that can then be transported to dryer regions of the plateau. Both processes demonstrate the importance of soil moisture and surface–atmosphere interactions on the energy and hydrological cycles of the Tibetan Plateau. This research was funded by the German Research Foundation (DFG) Priority Programme 1372 “Tibetan Plateau: Formation, Climate, Ecosystems” as part of the Atmosphere–Ecology–Glaciology–Cluster (TiP-AEG): FO 226/18- 1,2. The work described in this publication has been supported by the European Commission (Call FP7-ENV-2007-1 grant no. 212921) as part of the CEOP-AEGIS project coordinated by the University of Strasbourg. The map of Nam Co was produced by Sophie Biskop (University of Jena) and Jan Kropacek (University of Tübingen) within DFG-TiP and Phil Stickler of the Cambridge Geography Department Cartography Unit. This publication was funded by the German Research Foundation (DFG) and the University of Bayreuth in the funding programme Open-Access Publishing.This is the final version of the article. It first appeared from European Geosciences Union via http://dx.doi.org/10.5194/hess-19-4023-201

Development of a device to simulate tooth mobility

Objectives: The testing of new materials under simulation of oral conditions is essential in medicine. For simulation of fracture strength different simulation devices are used for test set-up. The results of these in vitro tests differ because there is no standardization of tooth mobility in simulation devices. The aim of this study is to develop a simulation device that depicts the tooth mobility curve as accurately as possible and creates reproducible and scalable mobility curves. Materials and methods: With the aid of published literature and with the help of dentists, average forms of tooth classes were generated. Based on these tooth data, different abutment tooth shapes and different simulation devices were designed with a CAD system and were generated with a Rapid Prototyping system. Then, for all simulation devices the displacement curves were created with a universal testing machine and compared with the tooth mobility curve. With this new information, an improved adapted simulation device was constructed. Results: A simulations device that is able to simulate the mobility curve of natural teeth with high accuracy and where mobility is reproducible and scalable was developed

Parenteral anticoagulation may prolong the survival of patients with limited small cell lung cancer: a Cochrane systematic review

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

The impact of oxygen on the transcriptome of recombinant S. cerevisiae and P. pastoris - a comparative analysis

Background: Saccharomyces cerevisiae and Pichia pastoris are two of the most relevant microbial eukaryotic platforms for the production of recombinant proteins. Their known genome sequences enabled several transcriptomic profiling studies under many different environmental conditions, thus mimicking not only perturbations and adaptations which occur in their natural surroundings, but also in industrial processes. Notably, the majority of such transcriptome analyses were performed using non-engineered strains. In this comparative study, the gene expression profiles of S. cerevisiae and P. pastoris, a Crabtree positive and Crabtree negative yeast, respectively, were analyzed for three different oxygenation conditions (normoxic, oxygen-limited and hypoxic) under recombinant protein producing conditions in chemostat cultivations. Results: The major differences in the transcriptomes of S. cerevisiae and P. pastoris were observed between hypoxic and normoxic conditions, where the availability of oxygen strongly affected ergosterol biosynthesis, central carbon metabolism and stress responses, particularly the unfolded protein response. Steady state conditions under low oxygen set-points seemed to perturb the transcriptome of S. cerevisiae to a much lesser extent than the one of P. pastoris, reflecting the major tolerance of the baker's yeast towards oxygen limitation, and a higher fermentative capacity. Further important differences were related to Fab production, which was not significantly affected by oxygen availability in S. cerevisiae, while a clear productivity increase had been previously reported for hypoxically grown P. pastoris. Conclusions: The effect of three different levels of oxygen availability on the physiology of P. pastoris and S. cerevisiae revealed a very distinct remodelling of the transcriptional program, leading to novel insights into the different adaptive responses of Crabtree negative and positive yeasts to oxygen availability. Moreover, the application of such comparative genomic studies to recombinant hosts grown in different environments might lead to the identification of key factors for efficient protein production

Chapter 12: Systematic Review of Prognostic Tests

A number of new biological markers are being studied as predictors of disease or adverse medical events among those who already have a disease. Systematic reviews of this growing literature can help determine whether the available evidence supports use of a new biomarker as a prognostic test that can more accurately place patients into different prognostic groups to improve treatment decisions and the accuracy of outcome predictions. Exemplary reviews of prognostic tests are not widely available, and the methods used to review diagnostic tests do not necessarily address the most important questions about prognostic tests that are used to predict the time-dependent likelihood of future patient outcomes. We provide suggestions for those interested in conducting systematic reviews of a prognostic test. The proposed use of the prognostic test should serve as the framework for a systematic review and to help define the key questions. The outcome probabilities or level of risk and other characteristics of prognostic groups are the most salient statistics for review and perhaps meta-analysis. Reclassification tables can help determine how a prognostic test affects the classification of patients into different prognostic groups, hence their treatment. Review of studies of the association between a potential prognostic test and patient outcomes would have little impact other than to determine whether further development as a prognostic test might be warranted

Local hyperthyroidism promotes pancreatic acinar cell proliferation during acute pancreatitis

Proliferation of pancreatic acinar cells is a critical process in the pathophysiology of pancreatic diseases, because limited or defective proliferation is associated with organ dysfunction and patient morbidity. In this context, elucidating the signalling pathways that trigger and sustain acinar proliferation is pivotal to develop therapeutic interventions promoting the regenerative process of the organ.In this study we used genetic and pharmacological approaches to manipulate both local and systemic levels of thyroid hormones to elucidate their role in acinar proliferation following caerulein‐mediated acute pancreatitis in mice. In addition, molecular mechanisms mediating the effects of thyroid hormones were identified by genetic and pharmacological inactivation of selected signalling pathways.In this study we demonstrated that levels of the thyroid hormone 3,3’,5‐triodo‐L‐thyronine (T3) transiently increased in the pancreas during acute pancreatitis. Moreover, by using genetic and pharmacological approaches to manipulate both local and systemic levels of thyroid hormones, we showed that T3 was required to promote proliferation of pancreatic acinar cells, without affecting the extent of tissue damage or inflammatory infiltration.Finally, upon genetic and pharmacological inactivation of selected signalling pathways, we demonstrated that T3 exerted its mitogenic effect on acinar cells via a tightly controlled action on different molecular effectors, including histone deacetylase, AKT, and TGFβ signalling.In conclusion, our data suggest that local availability of T3 in the pancreas is required to promote acinar cell proliferation and provide the rationale to exploit thyroid hormone signalling to enhance pancreatic regeneration