One of the key challenges in spectroscopy is the inhomogeneous broadening that masks the homogeneous spectral lineshape and the underlying coherent dynamics. Techniques such as four-wave mixing and ...spectral hole-burning are used in optical spectroscopy, and spin-echo4 in nuclear magnetic resonance (NMR). However, the high-power pulses used in spin-echo and other sequences often create spurious dynamics obscuring the subtle spin correlations important for quantum technologies. Here we develop NMR techniques to probe the correlation times of the fluctuations in a nuclear spin bath of individual quantum dots, using frequency-comb excitation, allowing for the homogeneous NMR lineshapes to be measured without high-power pulses.
We assessed whether a near-infrared spectroscopy (NIRS)-based algorithm for the personalized optimization of cerebral oxygenation during cardiopulmonary bypass combined with a restrictive red cell ...transfusion threshold would reduce perioperative injury to the brain, heart, and kidneys.
In a randomized controlled trial, participants in three UK centres were randomized with concealed allocation to a NIRS (INVOS 5100; Medtronic Inc., Minneapolis, MN, USA)-based ‘patient-specific’ algorithm that included a restrictive red cell transfusion threshold (haematocrit 18%) or to a ‘generic’ non-NIRS-based algorithm (standard care). The NIRS algorithm aimed to maintain cerebral oxygenation at an absolute value of > 50% or at > 70% of baseline values. The primary outcome for the trial was cognitive function measured up to 3 months postsurgery.
The analysis population comprised eligible randomized patients who underwent valve or combined valve surgery and coronary artery bypass grafts using cardiopulmonary bypass between December 2009 and January 2014 (n=98 patient-specific algorithm; n=106 generic algorithm). There was no difference between the groups for the three core cognitive domains (attention, verbal memory, and motor coordination) or for the non-core domains psychomotor speed and visuo-spatial skills. The NIRS group had higher scores for verbal fluency; mean difference 3.73 (95% confidence interval 1.50, 5.96). Red cell transfusions, biomarkers of brain, kidney, and myocardial injury, adverse events, and health-care costs were similar between the groups.
These results do not support the use of NIRS-based algorithms for the personalized optimization of cerebral oxygenation in adult cardiac surgery.
http://www.controlled-trials.com, ISRCTN 23557269.
There exists a great deal of concrete evidence in favor of the exotic four-quark nature of light scalars. At the same time, the further expansion of the area of the q2q2 model validity for light ...scalars on ever new processes seems extremely interesting and important. We analyze the BESIII data on the decay J/ψ → γπ0π0 and show that the results of this high-statistics experiment can be interpreted in favor of the four-quark nature of light scalar mesons f0(980) and f0 (500).
Atherosclerotic plaques develop as a consequence of the accumulation of circulating lipid and the subsequent migration of inflammatory cells (macrophages and T-lymphocytes) and VSMCs (vascular smooth ...muscle cells). Advanced plaques consist of a lipid-rich core, separated from the lumen by a fibrous cap composed of VSMCs, collagen and extracellular matrix. Plaque enlargement ultimately narrows the lumen (stenosis) causing angina. However, recent studies have emphasized that acute coronary syndromes (unstable angina/myocardial infarction) are caused by lesion erosion/rupture with superimposed thrombus formation on often small non-stenotic plaques. Thus current therapies work predominantly on stabilization of plaques rather than plaque regression. Apoptosis (programmed cell death) is increasingly observed as plaques develop, although the exact mechanisms and consequences of apoptosis in the development and progression of atherosclerosis are still controversial. Increased endothelial cell apoptosis may initiate atherosclerosis, whereas apoptosis of VSMCs and macrophages localizes in 'vulnerable' lesions, i.e. those most likely to rupture, and at sites of rupture. This review will focus on the regulation of apoptosis of cells within the vasculature, concentrating on the relevance of apoptosis to plaque progression and clinical consequences of vascular cell apoptosis.
Transposable genetic elements are abundant in the genomes of most organisms, including humans. These endogenous mutagens can alter genes, promote genomic rearrangements, and may help to drive the ...speciation of organisms. In this study, we identified almost 11,000 transposon copies that are differentially present in the human and chimpanzee genomes. Most of these transposon copies were mobilized after the existence of a common ancestor of humans and chimpanzees, ∼6 million years ago.
Alu, L1, and SVA insertions accounted for >95% of the insertions in both species. Our data indicate that humans have supported higher levels of transposition than have chimpanzees during the past several million years and have amplified different transposon subfamilies. In both species, ∼34% of the insertions were located within known genes. These insertions represent a form of species-specific genetic variation that may have contributed to the differential evolution of humans and chimpanzees. In addition to providing an initial overview of recently mobilized elements, our collections will be useful for assessing the impact of these insertions on their hosts and for studying the transposition mechanisms of these elements.
The precise anatomical location of pathology associated with inflammatory back pain (IBP) in early spondyloarthropathy (SpA) remains unclear.
To use MRI to study the sacroiliac joint (SIJ) and lumbar ...spine (LS) and explore the relationship between sites and extent of inflammation and HLA-B27 status over 12 months.
54 patients with IBP; median duration 24 weeks (54% HLA-B27 positive; median Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) 5.65) and 22 control subjects (11 with mechanical back pain; 11 volunteers) were recruited and 63% (n = 34) were reassessed at 1 year. Fat saturation and T1-weighted MRI was performed with images being scored for active bone marrow oedema (BMO) lesions representative of inflammation.
At baseline 46/54 (85%) patients had BMO (SIJs and LS) compared with 40% in the control group. The majority of affected patients had inflammation at the SIJ level (96% (n = 44); 23.5% (n = 12) LS) and 28.3% (n = 13) at both sites simultaneously. The SIJ activity score confirmed more severe inflammation (BMO grade 2 or 3: 52.2%) in the IBP group (controls = BMO grade 1: 100%; p<0.001). HLA-B27 was associated with both the severity (p = 0.009) and number of baseline SIJ lesions (p = 0.045) and with persistence (SIJ or LS) at 1 year (p = 0.02). 90% of reattenders fulfilled European Spondyloarthropathy Study Group criteria; 73.5% showed MRI inflammation despite clinical improvement (median BASDAI 5.65 to 3.05; p<0.009).
LS and SIJ involvement may occur simultaneously in very early SpA and may be differentiated from non-inflammatory back pain by the severity of MRI lesions. HLA-B27 is associated with both the severity of osteitis and its persistence.
Impaired cardiorespiratory fitness is associated with inferior survival in patients preparing to undergo hematopoietic cell transplantation (HCT). Exercise training based on short, higher intensity ...intervals has the potential to efficiently improve cardiorespiratory fitness. We studied home-based interval exercise training (IET) in 40 patients before autologous (N=20) or allogeneic (N=20) HCT. Each session consisted of five, 3 min intervals of walking, jogging or cycling at 65-95% maximal heart rate (MHR) with 3 min of low-intensity exercise (<65% MHR) between intervals. Participants were asked to perform sessions at least three times weekly. The duration of the intervention was at least 6 weeks, depending on each patient's scheduled transplantation date. Cardiorespiratory fitness was assessed from a peak oxygen consumption test (VO2peak) and a 6 min walk (6MWD) before and after the intervention period. For the autologous HCT cohort, improvements in VO2peak (P=0.12) and 6MWD (P=0.19) were not statistically significant. For the allogeneic cohort, the median VO2peak improvement was 3.7 ml/kg min (P=0.005) and the median 6MWD improvement was 34 m (P=0.006). Home-based IET can be performed before HCT and has the potential to improve cardiorespiratory fitness.
A number of studies have shown that an association with mycorrhizal fungi can alter the outcome of interactions between plants and their enemies. While the directions of these effects vary, their ...strength suggests the need for greater attention to multispecies interactions among plant enemies, plants, and mycorrhizal fungi. We recognize that mycorrhizal fungi could effect plant enemies by improving plant nutrition, modifying plant tolerance, or modifying plant defenses. In addition, mycorrhizal fungi could directly interfere with pathogen infection, herbivory, or parasitism by occupying root space. We formalize these alternative outcomes of multispecies interactions and explore the long‐term dynamics of the plant‐enemy interactions based on these different scenarios using a general model of interactions between plants and plant enemies. We then review the literature in terms of the assumptions of the alternative mechanisms and the predictions of these models. Through this effort, we identify new directions in the study of tritrophic interactions between enemies, plants, and soil mutualists.
Context. Microlensing is a unique method to probe low mass exoplanets beyond the snow line. However, the scientific potential of the new microlensing planet discovery is often unfulfilled due to lack ...of knowledge of the properties of the lens and source stars. The discovery light curve of the super Earth MOA-2007-BLG-192Lb suffers from significant degeneracies that limit what can be inferred about its physical properties. Aims. High resolution adaptive optics images allow us to solve this problem by resolving the microlensing target from all unrelated background stars, yielding the unique determination of magnified source and lens fluxes. This estimation permits the solution of our microlens model for the mass of the planet and its host and their physical projected separation. Methods. We observed the microlensing event MOA-2007-BLG-192 at high angular resolution in JHKs with the NACO adaptive optics system on the VLT while the object was still amplified by a factor 1.23 and then at baseline 18 months later. We analyzed and calibrated the NACO photometry in the standard 2MASS system in order to accurately constrain the source and the lens star fluxes. Results. We detect light from the host star of MOA-2007-BLG-192Lb, which significantly reduces the uncertainties in its characteristics as compared to earlier analyses. We find that MOA-2007-BLG-192L is most likely a very low mass late type M-dwarf (0.084-0.012+0.015 M⊙) at a distance of 660-70+100 pc orbited by a 3.2-1.8+5.2 M⊕ super-Earth at 0.66-0.22+0.51 AU. We then discuss the properties of this cold planetary system.
Permafrost soils are a critical component of the global carbon cycle and are locally important because they regulate the hydrologic flux from uplands to rivers. Furthermore, degradation of permafrost ...soils causes land surface subsidence, damaging infrastructure that is crucial for local communities. Regional and hemispherical maps of permafrost are too coarse to resolve distributions at a scale relevant to assessments of infrastructure stability or to illuminate geomorphic impacts of permafrost thaw. Here we train machine learning models to generate meter‐scale maps of near‐surface permafrost for three watersheds in the discontinuous permafrost region. The models were trained using ground truth determinations of near‐surface permafrost presence from measurements of soil temperature and electrical resistivity. We trained three classifiers: extremely randomized trees (ERTr), support vector machines (SVM), and an artificial neural network (ANN). Model uncertainty was determined using k‐fold cross validation, and the modeled extents of near‐surface permafrost were compared to the observed extents at each site. At‐a‐site near‐surface permafrost distributions predicted by the ERTr produced the highest accuracy (70%–90%). However, the transferability of the ERTr to the sites outside of the training data set was poor, with accuracies ranging from 50% to 77%. The SVM and ANN models had lower accuracies for at‐a‐site prediction (70%–83%), yet they had greater accuracy when transferred to the non‐training site (62%–78%). These models demonstrate the potential for integrating high‐resolution spatial data and machine learning models to develop maps of near‐surface permafrost extent at resolutions fine enough to assess infrastructure vulnerability and landscape morphology influenced by permafrost thaw.
Plain Language Summary
Accurate spatial assessments of the extent of near‐surface permafrost in regions of discontinuous permafrost are essential for evaluating the potential impacts of permafrost thaw. Most current estimates of permafrost extent are provided at the scale of 10s of meters to kilometers, which is often too coarse to understand the impacts thaw might have on infrastructure or geomorphic processes. We trained machine learning models to generate maps of near‐surface permafrost at 3 m spatial resolution in three sites in western Alaska. These maps provide an advancement in evaluating the extent of permafrost in the region as well as highlighting the landscape and ecological factors most important in driving predictions.
Key Points
High‐resolution maps of near‐surface permafrost on hillslopes were generated from machine learning models
The normalized difference vegetation index was the most important feature in prediction of near‐surface permafrost
The support vector machines generally generated the highest balanced accuracy for predictions at sites where the model was not trained
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