Wavelet-Based Detection of Outliers in Poisson INAR(1) Time Series

The presence of outliers or discrepant observations has a negative impact in time series modelling. This paper considers the problem of detecting outliers, additive or innovational, single, multiple or in patches, in count time series modelled by first-order Poisson integer-valued autoregressive, PoINAR(1), models. To address this problem, two wavelet-based approaches that allow the identification of the time points of outlier occurrence are proposed. The effectiveness of the proposed methods is illustrated with synthetic as well as with an observed dataset

Volcanism and carbon cycle perturbations in the High Arctic during the Late Jurassic – Early Cretaceous

This is the final version. Available on open access from Elsevier via the DOI in this recordLarge perturbations in the global carbon cycle recorded as carbon-isotope (δ13C) excursions (CIEs) in both organic carbon and carbonate records have been linked to volcanism during the emplacement of Large Igneous Provinces (LIPs). This link is based primarily on the purported temporal coincidence between CIEs and LIP emplacement. Mercury (Hg) concentration in sedimentary rocks has been used as a regional to global tracer of large-scale volcanic activity, yet few studies have been undertaken on Upper Jurassic – Lower Cretaceous sediments from Boreal localities compared to those for Tethyan (northern mid-latitude) successions. This has limited our understanding of the regional-to-global spatial impact of volcanic activity during this period. This study examines the Hg record as a proxy for volcanism, and the δ13C records from organic matter (δ13Corg) of CIEs from the uppermost Jurassic to Lower Cretaceous (Callovian – Aptian) successions from Axel Heiberg and Spitsbergen in the Canadian Arctic and Svalbard archipelagos, respectively. This interval includes three regional- to global CIEs. These sections show no significant variation in the ratio of Hg to total organic carbon (TOC) across the Boreal-wide Volgian negative CIE (Volgian Isotopic Carbon Excursion, “VOICE”), which has not been associated with LIP volcanism. The examined successions spanning this interval all show some influence from changing environmental or post-burial parameters, however, which could have (partially) overprinted a volcanic signal. Despite some problems in stratigraphically constraining the Weissert Event, increased Hg/TOC ratios are observed across this interval, which may be partially driven by volcanism associated with the emplacement of the Paraná-Etendeka Traps. A spike in Hg/TOC is observed immediately prior to the negative peak of the Aptian Oceanic Anoxic Event (OAE1a) CIE, supporting recent evidence of a pulse of High Arctic Large Igneous Province (HALIP) volcanic activity preceding this oceanic anoxic event

Functional Deficits in nNOSμ-Deficient Skeletal Muscle: Myopathy in nNOS Knockout Mice

Skeletal muscle nNOSμ (neuronal nitric oxide synthase mu) localizes to the sarcolemma through interaction with the dystrophin-associated glycoprotein (DAG) complex, where it synthesizes nitric oxide (NO). Disruption of the DAG complex occurs in dystrophinopathies and sarcoglycanopathies, two genetically distinct classes of muscular dystrophy characterized by progressive loss of muscle mass, muscle weakness and increased fatigability. DAG complex instability leads to mislocalization and downregulation of nNOSμ; but this is thought to play a minor role in disease pathogenesis. This view persists without knowledge of the role of nNOS in skeletal muscle contractile function in vivo and has influenced gene therapy approaches to dystrophinopathy, the majority of which do not restore sarcolemmal nNOSμ. We address this knowledge gap by evaluating skeletal muscle function in nNOS knockout (KN1) mice using an in situ approach, in which the muscle is maintained in its normal physiological environment. nNOS-deficiency caused reductions in skeletal muscle bulk and maximum tetanic force production in male mice only. Furthermore, nNOS-deficient muscles from both male and female mice exhibited increased susceptibility to contraction-induced fatigue. These data suggest that aberrant nNOSμ signaling can negatively impact three important clinical features of dystrophinopathies and sarcoglycanopathies: maintenance of muscle bulk, force generation and fatigability. Our study suggests that restoration of sarcolemmal nNOSμ expression in dystrophic muscles may be more important than previously appreciated and that it should be a feature of any fully effective gene therapy-based intervention

f(R) theories

Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity - such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present a number of ways to distinguish those theories from General Relativity observationally and experimentally. We also discuss the extension to other modified gravity theories such as Brans-Dicke theory and Gauss-Bonnet gravity, and address models that can satisfy both cosmological and local gravity constraints.Comment: 156 pages, 14 figures, Invited review article in Living Reviews in Relativity, Published version, Comments are welcom

Performance of the Quasar Spectral Templates for the Dark Energy Spectroscopic Instrument

Millions of quasar spectra will be collected by the Dark Energy Spectroscopic Instrument (DESI), leading to a fourfold increase in the number of known quasars. High-accuracy quasar classification is essential to tighten constraints on cosmological parameters measured at the highest redshifts DESI observes (z > 2.0). We present spectral templates for identification and redshift estimation of quasars in the DESI Year 1 data release. The quasar templates are comprised of two quasar eigenspectra sets, trained on spectra from the Sloan Digital Sky Survey. The sets are specialized to reconstruct quasar spectral variation observed over separate yet overlapping redshift ranges and, together, are capable of identifying DESI quasars from 0.05 < z < 7.0. The new quasar templates show significant improvement over the previous DESI quasar templates regarding catastrophic failure rates, redshift precision and accuracy, quasar completeness, and the contamination fraction in the final quasar sample

Sodium bicarbonate supplementation improves severe-intensity intermittent exercise under moderate acute hypoxic conditions

Acute moderate hypoxic exposure can substantially impair exercise performance, which occurs with a concurrent exacerbated rise in hydrogen cation (H+) production. The purpose of this study was therefore, to alleviate this acidic stress through sodium bicarbonate (NaHCO3) supplementation and determine the corresponding effects on severe intensity intermittent exercise performance. Eleven recreationally active individuals participated in this randomised, double-blind, crossover study performed under acute normobaric hypoxic conditions (FiO2% = 14.5%). Pre-experimental trials involved the determination of time to attain peak bicarbonate anion concentrations ([HCO3-]) following NaHCO3 ingestion. The intermittent exercise tests involved repeated 60 s work in their severe intensity domain and 30 s recovery at 20 W to exhaustion. Participants ingested either 0.3 g·kg bm-1 of NaHCO3 or a matched placebo of 0.21 g·kg bm-1 of sodium chloride prior to exercise. Exercise tolerance (+110.9 ± 100.6 s; 95% CI: 43.3 to 178 s; g = 1.0) and work performed in the severe intensity domain (+5.8 ± 6.6 kJ; 95% CI: 1.3 to 9.9 kJ; g = 0.8) were enhanced with NaHCO3 supplementation. Furthermore, a larger post-exercise blood lactate concentration was reported in the experimental group (+4 ± 2.4 mmol·l-1; 95% CI: 2.2 to 5.9; g = 1.8), while blood [HCO3-] and pH remained elevated in the NaHCO3 condition throughout experimentation. In conclusion, this study reported a positive effect of NaHCO3 under acute moderate hypoxic conditions during intermittent exercise and therefore, may offer an ergogenic strategy to mitigate hypoxic induced declines in exercise performance

The influence of alkalosis on repeated high-intensity exercise performance and acid–base balance recovery in acute moderate hypoxic conditions

Purpose Exacerbated hydrogen cation (H⁺) production is suggested to be a key determinant of fatigue in acute hypoxic conditions. This study, therefore, investigated the effects of NaHCO3 ingestion on repeated 4 km TT cycling performance and post-exercise acid–base balance recovery in acute moderate hypoxic conditions. Methods Ten male trained cyclists completed four repeats of 2 × 4 km cycling time trials (TT1 and TT2) with 40 min passive recovery, each on different days. Each TT series was preceded by supplementation of one of the 0.2 g kg⁻¹ BM NaHCO3 (SBC2), 0.3 g kg⁻¹ BM NaHCO3 (SBC3), or a taste-matched placebo (0.07 g kg⁻¹ BM sodium chloride; PLA), administered in a randomized order. Supplements were administered at a pre-determined individual time to peak capillary blood bicarbonate concentration ([HCO3⁻]). Each TT series was also completed in a normobaric hypoxic chamber set at 14.5% FiO2 (~ 3000 m). Results Performance was improved following SBC3 in both TT1 (400.2 ± 24.1 vs. 405.9 ± 26.0 s; p = 0.03) and TT2 (407.2 ± 29.2 vs. 413.2 ± 30.8 s; p = 0.01) compared to PLA, displaying a very likely benefit in each bout. Compared to SBC2, a likely and possible benefit was also observed following SBC3 in TT1 (402.3 ± 26.5 s; p = 0.15) and TT2 (410.3 ± 30.8 s; p = 0.44), respectively. One participant displayed an ergolytic effect following SBC3, likely because of severe gastrointestinal discomfort, as SBC2 still provided ergogenic effects. Conclusion NaHCO3 ingestion improves repeated exercise performance in acute hypoxic conditions, although the optimal dose is likely to be 0.3 g kg⁻¹ BM

Predicting Human Nucleosome Occupancy from Primary Sequence

Nucleosomes are the fundamental repeating unit of chromatin and comprise the structural building blocks of the living eukaryotic genome. Micrococcal nuclease (MNase) has long been used to delineate nucleosomal organization. Microarray-based nucleosome mapping experiments in yeast chromatin have revealed regularly-spaced translational phasing of nucleosomes. These data have been used to train computational models of sequence-directed nuclesosome positioning, which have identified ubiquitous strong intrinsic nucleosome positioning signals. Here, we successfully apply this approach to nucleosome positioning experiments from human chromatin. The predictions made by the human-trained and yeast-trained models are strongly correlated, suggesting a shared mechanism for sequence-based determination of nucleosome occupancy. In addition, we observed striking complementarity between classifiers trained on experimental data from weakly versus heavily digested MNase samples. In the former case, the resulting model accurately identifies nucleosome-forming sequences; in the latter, the classifier excels at identifying nucleosome-free regions. Using this model we are able to identify several characteristics of nucleosome-forming and nucleosome-disfavoring sequences. First, by combining results from each classifier applied de novo across the human ENCODE regions, the classifier reveals distinct sequence composition and periodicity features of nucleosome-forming and nucleosome-disfavoring sequences. Short runs of dinucleotide repeat appear as a hallmark of nucleosome-disfavoring sequences, while nucleosome-forming sequences contain short periodic runs of GC base pairs. Second, we show that nucleosome phasing is most frequently predicted flanking nucleosome-free regions. The results suggest that the major mechanism of nucleosome positioning in vivo is boundary-event-driven and affirm the classical statistical positioning theory of nucleosome organization

The Dark Energy Spectroscopic Instrument (DESI)

We present the status of the Dark Energy Spectroscopic Instrument (DESI) and its plans and opportunities for the coming decade. DESI construction and its initial five years of operations are an approved experiment of the US Department of Energy and is summarized here as context for the Astro2020 panel. Beyond 2025, DESI will require new funding to continue operations. We expect that DESI will remain one of the world's best facilities for wide-field spectroscopy throughout the decade. More about the DESI instrument and survey can be found at https://www.desi.lbl.gov

Astrometric Calibration and Performance of the Dark Energy Spectroscopic Instrument Focal Plane

The Dark Energy Spectroscopic Instrument, consisting of 5020 robotic fiber positioners and associated systems on the Mayall telescope at Kitt Peak, Arizona, is carrying out a survey to measure the spectra of 40 million galaxies and quasars and produce the largest 3D map of the universe to date. The primary science goal is to use baryon acoustic oscillations to measure the expansion history of the universe and the time evolution of dark energy. A key function of the online control system is to position each fiber on a particular target in the focal plane with an accuracy of 11 μm rms 2D. This paper describes the set of software programs used to perform this function along with the methods used to validate their performance