A multi-model comparison of Atlantic multidecadal variability

A multi-model analysis of Atlantic multidecadal variability is performed with the following aims: to investigate the similarities to observations; to assess the strength and relative importance of the different elements of the mechanism proposed by Delworth et al. (J Clim 6:1993–2011, 1993) (hereafter D93) among coupled general circulation models (CGCMs); and to relate model differences to mean systematic error. The analysis is performed with long control simulations from ten CGCMs, with lengths ranging between 500 and 3600 years. In most models the variations of sea surface temperature (SST) averaged over North Atlantic show considerable power on multidecadal time scales, but with different periodicity. The SST variations are largest in the mid-latitude region, consistent with the short instrumental record. Despite large differences in model configurations, we find quite some consistency among the models in terms of processes. In eight of the ten models the mid-latitude SST variations are significantly correlated with fluctuations in the Atlantic meridional overturning circulation (AMOC), suggesting a link to northward heat transport changes. Consistent with this link, the three models with the weakest AMOC have the largest cold SST bias in the North Atlantic. There is no linear relationship on decadal timescales between AMOC and North Atlantic Oscillation in the models. Analysis of the key elements of the D93 mechanisms revealed the following: Most models present strong evidence that high-latitude winter mixing precede AMOC changes. However, the regions of wintertime convection differ among models. In most models salinity-induced density anomalies in the convective region tend to lead AMOC, while temperature-induced density anomalies lead AMOC only in one model. However, analysis shows that salinity may play an overly important role in most models, because of cold temperature biases in their relevant convective regions. In most models subpolar gyre variations tend to lead AMOC changes, and this relation is strong in more than half of the models.

First πK atom lifetime and πK scattering length measurements

The results of a search for hydrogen-like atoms consisting of π∓K±π∓K± mesons are presented. Evidence for πK atom production by 24 GeV/c protons from CERN PS interacting with a nickel target has been seen in terms of characteristic πK pairs from their breakup in the same target (178±49178±49) as well as in terms of produced πK atoms (653±42653±42). Using these results, the analysis yields a first value for the πK atom lifetime of View the MathML sourceτ=(2.5−1.8+3.0) fs and a first measurement of the S-wave isospin-odd πK scattering length View the MathML source|a0−|=13|a1/2−a3/2|=(0.11−0.04+0.09)Mπ−1 (aIaI for isospin I).

CODE’s new solar radiation pressure model for GNSS orbit determination

The Empirical CODE Orbit Model (ECOM) of the Center for Orbit Determination in Europe (CODE), which was developed in the early 1990s, is widely used in the International GNSS Service (IGS) community. For a rather long time, spurious spectral lines are known to exist in geophysical parameters, in particular in the Earth Rotation Parameters (ERPs) and in the estimated geocenter coordinates, which could recently be attributed to the ECOM. These effects grew creepingly with the increasing influence of the GLONASS system in recent years in the CODE analysis, which is based on a rigorous combination of GPS and GLONASS since May 2003. In a first step we show that the problems associated with the ECOM are to the largest extent caused by the GLONASS, which was reaching full deployment by the end of 2011. GPS-only, GLONASS-only, and combined GPS/GLONASS solutions using the observations in the years 2009–2011 of a global network of 92 combined GPS/GLONASS receivers were analyzed for this purpose. In a second step we review direct solar radiation pressure (SRP) models for GNSS satellites. We demonstrate that only even-order short-period harmonic perturbations acting along the direction Sun-satellite occur for GPS and GLONASS satellites, and only odd-order perturbations acting along the direction perpendicular to both, the vector Sun-satellite and the spacecraft’s solar panel axis. Based on this insight we assess in the third step the performance of four candidate orbit models for the future ECOM. The geocenter coordinates, the ERP differences w. r. t. the IERS 08 C04 series of ERPs, the misclosures for the midnight epochs of the daily orbital arcs, and scale parameters of Helmert transformations for station coordinates serve as quality criteria. The old and updated ECOM are validated in addition with satellite laser ranging (SLR) observations and by comparing the orbits to those of the IGS and other analysis centers. Based on all tests, we present a new extended ECOM which substantially reduces the spurious signals in the geocenter coordinate z (by about a factor of 2–6), reduces the orbit misclosures at the day boundaries by about 10 %, slightly improves the consistency of the estimated ERPs with those of the IERS 08 C04 Earth rotation series, and substantially reduces the systematics in the SLR validation of the GNSS orbits.

The Inverted Phantom Giant

In his famous children’s book, “Jim Button and Luke the Engine Driver”, Michael Ende describes a curious character: A phantom giant. Clothed in rags and with a long beard, the phantom giant appears enormous from far away, but shrinks to normal size as one gets closer. Most people avoid the poor creature, but the ones that dare approach it encounter a gentle, lonely being called Mr. Tur Tur. Chemical ecology is just the opposite of Mr. Tur Tur: A phantom dwarf. Or, in other words, an inverted phantom giant. From a distance, chemical ecology appears like a slightly odd, marginal section of biology and chemistry. But, as the interested scholar approaches, it starts growing and very quickly reaches gigantic dimensions, because all life is explained by chemistry, and all biological chemistry is guided by ecological principles. Herein lies the difficulty with chemical ecology: As it is not perceived well by biologists and chemists, few approach it to understand its significance, and the ones that do find themselves in front of a giant that defies their attempts to define and contain it. This is where the Journal of Chemical Ecology comes in: It invites us to take a closer look at an underestimated discipline and supports us to explore it and deal with its multidimensionality through the promotion of knowledge and methods. These services are unique and make the journal stand out of the crowd of scientific journals. Writing children’s books has become difficult in the era of information technology. And, so has the job of the Journal of Chemical Ecology. Young scientists gather information through accessible, dynamic websites and social platforms. They want articles that are available through a single mouse click, anywhere, anytime. They prefer advanced interactive hypertext protocols over clumsy pdf files. They care about transparency, non-profit and open access just as much as about traditional journal properties. In my view, reaching “the kids” is the major challenge of the Journal over the next years. Promoting an inverted phantom giant in the 21st century requires a combination of high-quality information and boosted visibility. In Michael Ende’s book, Jim and Luke follow exactly this strategy with Mr. Tur Tur: They become friends and offer him a job as a living lighthouse to protect their small island. They combine a quality relationship with high visibility, et voilà, the story ends well! I am looking forward to seeing if the Journal of Chemical Ecology will follow a similar path to reach the next generation of biologists and chemists. If yes, there is a good chance that in 40 years from now, somebody will write a laudation and refer to another famous book by Michael Ende: “The Neverending Story”.

CRTC2 polymorphism as a risk factor for the incidence of metabolic syndrome in patients with solid organ transplantation.

Metabolic syndrome after transplantation is a major concern following solid organ transplantation (SOT). The CREB-regulated transcription co-activator 2 (CRTC2) regulates glucose metabolism. The effect of CRTC2 polymorphisms on new-onset diabetes after transplantation (NODAT) was investigated in a discovery sample of SOT recipients (n1=197). Positive results were tested for replication in two samples from the Swiss Transplant Cohort Study (STCS, n2=1294 and n3=759). Obesity and other metabolic traits were also tested. Associations with metabolic traits in population-based samples (n4=46'186, n5=123'865, n6>100,000) were finally analyzed. In the discovery sample, CRTC2 rs8450-AA genotype was associated with NODAT, fasting blood glucose and body mass index (Pcorrected<0.05). CRTC2 rs8450-AA genotype was associated with NODAT in the second STCS replication sample (odd ratio (OR)=2.01, P=0.04). In the combined STCS replication samples, the effect of rs8450-AA genotype on NODAT was observed in patients having received SOT from a deceased donor and treated with tacrolimus (n=395, OR=2.08, P=0.02) and in non-kidney transplant recipients (OR=2.09, P=0.02). Moreover, rs8450-AA genotype was associated with overweight or obesity (n=1215, OR=1.56, P=0.02), new-onset hyperlipidemia (n=1007, OR=1.76, P=0.007), and lower high-density lipoprotein-cholesterol (n=1214, β=-0.08, P=0.001). In the population-based samples, a proxy of rs8450G>A was significantly associated with several metabolic abnormalities. CRTC2 rs8450G>A appears to have an important role in the high prevalence of metabolic traits observed in patients with SOT. A weak association with metabolic traits was also observed in the population-based samples.The Pharmacogenomics Journal advance online publication, 8 December 2015; doi:10.1038/tpj.2015.82.

In vitro analysis of osteogenic inhibition in non-union spinal fusion caused by nucleus pulposus cells.

Discectomy and spinal fusion is the gold standard for spinal surgery to relieve pain. However, fusion can be hindered for yet unknown reasons that lead to non-fusions with pseudo-arthrosis. Clinical observations indicate that presence of residual intervertebral disc (IVD) tissue might hinder the ossification. We hypothesize that BMP-antagonists are constantly secreted by IVD cells and potentially prevent the ossification process. Furthermore, L51P, the engineered BMP2 variant, stimulates osseo-induction of bone marrow-derived mesenchymal stem cells (MSC) by antagonizing BMP-inhibitors. Human MSCs, primary nucleus pulposus (NPC) and annulus pulposus cells (AFC) were isolated and expanded in monolayer cultures up to passage 3. IVD cells were seeded in 1.2% alginate beads (4Mio/mL) and separated by culture inserts from MSCs. MSCs were kept in 1:control medium, 2:osteogenic medium±alginate beads, 3:osteogenic medium+NPC (±L51P) and 4:osteogenic medium+AFC (±L51P) for 21 days. Relative gene expression of bone-related genes, alkaline phosphatase assay and histological staining were performed. Osteogenesis of MSCs was hindered as shown by reduced alizarin red staining in the presence of NPC. No such inhibition was observed if co-cultured with alginate only or in the presence of AFC. The results were confirmed on the RNA and protein level. Addition of L51Pto the co- cultures, however, induced mineralization of MSCs in presence of NPC. We demonstrated that NPC secrete BMP-antagonists that prevent osteogenesis of MSCs and L51P can antagonize BMP-antagonists and induce bone formation.

Cycling in the nucleus: regulation of RNA 3' processing and nuclear organization of replication-dependent histone genes.

The histones which pack new DNA during the S phase of animal cells are made from mRNAs that are cleaved at their 3' end but not polyadenylated. Some of the factors used in this reaction are unique to it while others are shared with the polyadenylation process that generates all other mRNAs. Recent work has begun to shed light on how the cell manages the assignment of these common components to the two 3' processing systems, and how it achieves their cell cycle-regulation and recruitment to the histone pre-mRNA. Moreover, recent and older findings reveal multiple connections between the nuclear organization of histone genes, their transcription and 3' end processing as well as the control of cell proliferation.

The Osr1 and Osr2 genes act in the pronephric anlage downstream of retinoic acid signaling and upstream of Wnt2b to maintain pectoral fin development.

Vertebrate odd-skipped related genes (Osr) have an essential function during the formation of the intermediate mesoderm (IM) and the kidney structures derived from it. Here, we show that these genes are also crucial for limb bud formation in the adjacent lateral plate mesoderm (LPM). Reduction of zebrafish Osr function impairs fin development by the failure of tbx5a maintenance in the developing pectoral fin bud. Osr morphant embryos show reduced wnt2b expression, and increasing Wnt signaling in Osr morphant embryos partially rescues tbx5a expression. Thus, Osr genes control limb bud development in a non-cell-autonomous manner, probably through the activation of Wnt2b. Finally, we demonstrate that Osr genes are downstream targets of retinoic acid (RA) signaling. Therefore, Osr genes act as a relay within the genetic cascade of fin bud formation: by controlling the expression of the signaling molecule Wnt2ba in the IM they play an essential function transmitting the RA signaling originated in the somites to the LPM.

A photopolymerized composite hydrogel and surgical implanting tool for a nucleus pulposus replacement

Nucleus pulposus replacements have been subjected to highly controversial discussions over the last 40 years. Their use has not yet resulted in a positive outcome to treat herniated disc or degenerated disc disease. The main reason is that not a single implant or tissue replacement was able to withstand the loads within an intervertebral disc. Here, we report on the development of a photo-polymerizable poly(ethylene glycol)dimethacrylate nano-fibrillated cellulose composite hydrogel which was tuned according to native tissue properties. Using a customized minimally-invasive medical device to inject and photopolymerize the hydrogel insitu, samples were implanted through an incision of 1 mm into an intervertebral disc of a bovine organ model to evaluate their long-term performance. When implanted into the bovine disc model, the composite hydrogel implant was able to significantly re-establish disc height after surgery (p < 0.0025). The height was maintained after 0.5 million loading cycles (p < 0.025). The mechanical resistance of the novel composite hydrogel material combined with the minimally invasive implantation procedure into a bovine disc resulted in a promising functional orthopedic implant for the replacement of the nucleus pulposus.

Lipschitz extensions of maps between Heisenberg groups

Let $\H^n$ be the Heisenberg group of topological dimension 2n+1 . We prove that if n is odd, the pair of metric spaces $(\H^n, \H^n)$ does not have the Lipschitz extension property.

Effects of subthalamic nucleus stimulation on cognition and mood in Parkinson’s disease (PD)

Objective: To assess the neuropsychological outcome as a safety measure and quality control in patients with subthalamic nucleus (STN) stimulation for PD. Background: Deep brain stimulation (DBS) is considered a relatively safe treatment used in patients with movement disorders. However, neuropsychological alterations have been reported in patients with STN DBS for PD. Cognition and mood are important determinants of quality of life in PD patients and must be assessed for safety control. Methods: Seventeen consecutive patients (8 women) who underwent STN DBS for PD have been assessed before and 4 months after surgery. Besides motor symptoms (UPDRS-III), mood (Beck Depression Inventory, Hamilton Depression Rating Scale) and neuropsychological aspects, mainly executive functions, have been assessed (mini mental state examination, semantic and phonematic verbal fluency, go-no go test, stroop test, trail making test, tests of alertness and attention, digit span, wordlist learning, praxia, Boston naming test, figure drawing, visual perception). Paired t-tests were used for comparisons before and after surgery. Results: Patients were 61.6±7.8 years old at baseline assessment. All surgeries were performed without major adverse events. Motor symptoms ‘‘on’’ medication remained stable whereas they improved in the ‘‘off’’ condition (p<0.001). Mood was not depressed before surgery and remained unchanged at follow-up. All neuropsychological assessment outcome measures remained stable at follow-up with the exception of semantic verbal fluency and wordlist learning. Semantic verbal fluency decreased by 21±16% (p<0.001) and there was a trend to worse phonematic verbal fluency after surgery (p=0.06). Recall of a list of 10 words was worse after surgery only for the third attempt of recall (13%, p<0.005). Conclusions: Verbal fluency decreased in our patients after STN DBS, as previously reported. The procedure was otherwise safe and did not lead to deterioration of mood.

Spectrophotometric properties of the nucleus of comet 67P/Churyumov-Gerasimenko from the OSIRIS instrument onboard the ROSETTA spacecraft

Context. The Rosetta mission of the European Space Agency has been orbiting the comet 67P/Churyumov-Gerasimenko (67P) since August 2014 and is now in its escort phase. A large complement of scientific experiments designed to complete the most detailed study of a comet ever attempted are onboard Rosetta. Aims. We present results for the photometric and spectrophotometric properties of the nucleus of 67P derived from the OSIRIS imaging system, which consists of a Wide Angle Camera (WAC) and a Narrow Angle Camera (NAC). The observations presented here were performed during July and the beginning of August 2014, during the approach phase, when OSIRIS was mapping the surface of the comet with several filters at different phase angles (1.3 degrees-54 degrees). The resolution reached up to 2.1 m/px. Methods. The OSIRIS images were processed with the OSIRIS standard pipeline, then converted into I/F. radiance factors and corrected for the illumination conditions at each pixel using the Lommel-Seeliger disk law. Color cubes of the surface were produced by stacking registered and illumination-corrected images. Furthermore, photometric analysis was performed both on disk-averaged photometry in several filters and on disk-resolved images acquired with the NAC orange filter, centered at 649 ran, using Hapke modeling. Results. The disk-averaged phase function of the nucleus of 67P shows a strong opposition surge with a G parameter value of -0.13 +/- 0.01 in the HG system formalism and an absolute magnitude H-v(1, 1, 0) = 15.74 +/- 0.02 mag. The integrated spectrophotometry in 20 filters covering the 250-1000 nm wavelength range shows a red spectral behavior, without clear absorption bands except for a potential absorption centered at similar to 290 rim that is possibly due to SO2 ice. The nucleus shows strong phase reddening, with disk-averaged spectral slopes increasing from 11%/( 100 nm) to 16%/(100 nm) in the 1.3 degrees-54 degrees phase angle range. The geometric albedo of the comet is 6.5 +/- 0.2% at 649 nm, with local variations of up to similar to 16% in the Hapi region. From the disk-resolved images we computed the spectral slope together with local spectrophotometry and identified three distinct groups of regions (blue, moderately red, and red). The Hapi region is the brightest, the bluest in term of spectral slope, and the most active surface on the comet. Local spectrophotometry shows an enhancement of the flux in the 700-750 nm that is associated with coma emissions.