A 5-day, eucaloric high fat diet up-regulates genes involved in fat metabolism in skeletal muscle of lean, but not obese, individuals.
Context:
In lean individuals, increasing dietary lipid can ...elicit an increase in whole body lipid oxidation; however, with obesity the capacity to respond to changes in substrate availability appears to be compromised.
Objective:
To determine whether the responses of genes regulating lipid oxidation in skeletal muscle differed between lean and insulin resistant obese humans upon exposure to a high-fat diet (HFD).
Design and Setting:
A 5-d prospective study conducted in the research unit of an academic center.
Participants:
Healthy, lean (n = 12; body mass index = 22.1 ± 0.6 kg/m2), and obese (n=10; body mass index = 39.6 ± 1.7 kg/m2) males and females, between ages 18 and 30.
Intervention:
Participants were studied before and after a 5-d HFD (65% fat).
Main Outcome Measures:
Skeletal muscle biopsies (vastus lateralis) were obtained in the fasted and fed states before and after the HFD and mRNA content for genes involved with lipid oxidation determined. Skeletal muscle acylcarnitine content was determined in the fed states before and after the HFD.
Results:
Peroxisome proliferator activated receptor (PPAR) α mRNA content increased in lean, but not obese, subjects after a single high-fat meal. From Pre- to Post-HFD, mRNA content exhibited a body size × HFD interaction, where the lean individuals increased while the obese individuals decreased mRNA content for pyruvate dehydrogenase kinase 4, uncoupling protein 3, PPARα, and PPARγ coactivator-1α (P ≤ 0.05). In the obese subjects medium-chain acylcarnitine species tended to accumulate, whereas no change or a reduction was evident in the lean individuals.
Conclusions:
These findings indicate a differential response to a lipid stimulus in the skeletal muscle of lean and insulin resistant obese humans.
In this paper we present a clustering analysis of quasi-stellar objects (QSOs) using over 20000 objects from the final catalogue of the 2dF QSO Redshift Survey (2QZ), measuring the redshift-space ...two-point correlation function, ξ(s). When averaged over the redshift range 0.3 < z < 2.2 we find that ξ(s) is flat on small scales, steepening on scales above ∼25h−1 Mpc. In a WMAP/2dF cosmology (Ωm = 0.27, ΩΛ = 0.73) we find a best-fitting power law with s0 = 5.48+0.42−0.48h−1 Mpc and γ= 1.20 ± 0.10 on scales s = 1 to 25h−1 Mpc. We demonstrate that non-linear redshift-space distortions have a significant effect on the QSO ξ(s) at scales less than ∼10h−1 Mpc. A cold dark matter model assuming WMAP/2dF cosmological parameters is a good description of the QSO ξ(s) after accounting for non-linear clustering and redshift-space distortions, and allowing for a linear bias at the mean redshift of bQ(z = 1.35) = 2.02 ± 0.07. We subdivide the 2QZ into 10 redshift intervals with effective redshifts from z = 0.53 to 2.48. We find a significant increase in clustering amplitude at high redshift in the WMAP/2dF cosmology. The QSO clustering amplitude increases with redshift such that the integrated correlation function, , within 20h−1 Mpc is and . We derive the QSO bias and find it to be a strong function of redshift with bQ(z = 0.53) = 1.13 ± 0.18 and bQ(z = 2.48) = 4.24 ± 0.53. We use these bias values to derive the mean dark matter halo (DMH) mass occupied by the QSOs. At all redshifts 2QZ QSOs inhabit approximately the same mass DMHs with MDH = (3.0 ± 1.6) × 1012h−1 M⊙, which is close to the characteristic mass in the Press–Schechter mass function, M*, at z = 0. These results imply that L*Q QSOs at z∼ 0 should be largely unbiased. If the relation between black hole (BH) mass and MDH or host velocity dispersion does not evolve, then we find that the accretion efficiency (L/LEdd) for L*Q QSOs is approximately constant with redshift. Thus the fading of the QSO population from z∼ 2 to ∼0 appears to be due to less massive BHs being active at low redshift. We apply different methods to estimate, tQ, the active lifetime of QSOs and constrain tQ to be in the range 4 × 106–6 × 108 yr at z∼ 2. We test for any luminosity dependence of QSO clustering by measuring ξ(s) as a function of apparent magnitude (equivalent to luminosity relative to L*Q). However, we find no significant evidence of luminosity-dependent clustering from this data set.
Data from the satellite-based Special Sensor Microwave Imager (SSM/I) show that the total atmospheric moisture content over oceans has increased by 0.41 kg/m² per decade since 1988. Results from ...current climate models indicate that water vapor increases of this magnitude cannot be explained by climate noise alone. In a formal detection and attribution analysis using the pooled results from 22 different climate models, the simulated "fingerprint" pattern of anthropogenically caused changes in water vapor is identifiable with high statistical confidence in the SSM/I data. Experiments in which forcing factors are varied individually suggest that this fingerprint "match" is primarily due to human-caused increases in greenhouse gases and not to solar forcing or recovery from the eruption of Mount Pinatubo. Our findings provide preliminary evidence of an emerging anthropogenic signal in the moisture content of earth's atmosphere.
The FLASHForward experimental facility is a high-performance test-bed for precision plasma wakefield research, aiming to accelerate high-quality electron beams to GeV-levels in a few centimetres of ...ionized gas. The plasma is created by ionizing gas in a gas cell either by a high-voltage discharge or a high-intensity laser pulse. The electrons to be accelerated will either be injected internally from the plasma background or externally from the FLASH superconducting RF front end. In both cases, the wakefield will be driven by electron beams provided by the FLASH gun and linac modules operating with a 10 Hz macro-pulse structure, generating 1.25 GeV, 1 nC electron bunches at up to 3 MHz micro-pulse repetition rates. At full capacity, this FLASH bunch-train structure corresponds to 30 kW of average power, orders of magnitude higher than drivers available to other state-of-the-art LWFA and PWFA experiments. This high-power functionality means FLASHForward is the only plasma wakefield facility in the world with the immediate capability to develop, explore and benchmark high-average-power plasma wakefield research essential for next-generation facilities. The operational parameters and technical highlights of the experiment are discussed, as well as the scientific goals and high-average-power outlook. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.
Toxoplasma gondii is among the most prevalent parasites worldwide, infecting many wild and domestic animals and causing zoonotic infections in humans. T. gondii differs substantially in its broad ...distribution from closely related parasites that typically have narrow, specialized host ranges. To elucidate the genetic basis for these differences, we compared the genomes of 62 globally distributed T. gondii isolates to several closely related coccidian parasites. Our findings reveal that tandem amplification and diversification of secretory pathogenesis determinants is the primary feature that distinguishes the closely related genomes of these biologically diverse parasites. We further show that the unusual population structure of T. gondii is characterized by clade-specific inheritance of large conserved haploblocks that are significantly enriched in tandemly clustered secretory pathogenesis determinants. The shared inheritance of these conserved haploblocks, which show a different ancestry than the genome as a whole, may thus influence transmission, host range and pathogenicity.
Abstract
We present a Monte Carlo–based population synthesis study of fast radio burst (FRB) dispersion and scattering focusing on the first catalog of sources detected with the Canadian Hydrogen ...Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) project. We simulate intrinsic properties and propagation effects for a variety of FRB population models and compare the simulated distributions of dispersion measures and scattering timescales with the corresponding distributions from the CHIME/FRB catalog. Our simulations confirm the results of previous population studies, which suggested that the interstellar medium of the host galaxy alone (simulated based on the NE2001 model) cannot explain the observed scattering timescales of FRBs. We therefore consider additional sources of scattering, namely, the circumgalactic medium (CGM) of intervening galaxies and the circumburst medium whose properties are modeled based on typical Galactic plane environments. We find that a population of FRBs with scattering contributed by these media is marginally consistent with the CHIME/FRB catalog. In this scenario, our simulations favor a population of FRBs offset from their galaxy centers over a population that is distributed along the spiral arms. However, if the models proposing the CGM as a source of intense scattering are incorrect, then we conclude that FRBs may inhabit environments with more extreme properties than those inferred for pulsars in the Milky Way.
We report the detection of a single burst from the first-discovered repeating fast radio burst (FRB) source, FRB 121102, with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope, ...which operates in the frequency band 400-800 MHz. The detected burst occurred on 2018 November 19 and its emission extends down to at least 600 MHz, the lowest frequency detection of this source yet. The burst, detected with a significance of 23.7 , has fluence 12 3 Jy ms and shows complex time and frequency morphology. The 34 ms width of the burst is the largest seen for this object at any frequency. We find evidence of subburst structure that drifts downward in frequency at a rate of −3.9 0.2 MHz ms−1. Our best fit tentatively suggests a dispersion measure of 563.6 0.5 pc cm−3, which is 1% higher than previously measured values. We set an upper limit on the scattering time at 500 MHz of 9.6 ms, which is consistent with expectations from the extrapolation from higher-frequency data. We have exposure to the position of FRB 121102 for a total of 11.3 hr within the FWHM of the synthesized beams at 600 MHz from 2018 July 25 to 2019 February 25. We estimate on the basis of this single event an average burst rate for FRB 121102 of 0.1-10 per day in the 400-800 MHz band for a median fluence threshold of 7 Jy ms in the stated time interval.
Toxoplasma gondii is one of the most successful protozoan parasites owing to its ability to manipulate the immune system and establish a chronic infection. There are many
T. gondii strains but the ...majority identified in Europe and North America falls into three distinct clonal lineages. Many studies have investigated the ability of
T. gondii to manipulate its host but few have examined directly whether the three lineages differ in this ability.
Summary
Background
Food allergy is a common cause of anaphylaxis, but the incidence of fatal food anaphylaxis is not known. The aim of this study was to estimate the incidence of fatal food ...anaphylaxis for people with food allergy and relate this to other mortality risks in the general population.
Methods
We undertook a systematic review and meta‐analysis, using the generic inverse variance method. Two authors selected studies by consensus, independently extracted data and assessed the quality of included studies using the Newcastle‐Ottawa assessment scale. We searched Medline, Embase, PsychInfo, CINAHL, Web of Science, LILACS or AMED, between January 1946 and September 2012, and recent conference s. We included registries, databases or cohort studies which described the number of fatal food anaphylaxis cases in a defined population and time period and applied an assumed population prevalence rate of food allergy.
Results
We included data from 13 studies describing 240 fatal food anaphylaxis episodes over an estimated 165 million food‐allergic person‐years. Study quality was mixed, and there was high heterogeneity between study results, possibly due to variation in food allergy prevalence and data collection methods. In food‐allergic people, fatal food anaphylaxis has an incidence rate of 1.81 per million person‐years (95%CI 0.94, 3.45; range 0.63, 6.68). In sensitivity analysis with different estimated food allergy prevalence, the incidence varied from 1.35 to 2.71 per million person‐years. At age 0–19, the incidence rate is 3.25 (1.73, 6.10; range 0.94, 15.75; sensitivity analysis 1.18–6.13). The incidence of fatal food anaphylaxis in food‐allergic people is lower than accidental death in the general European population.
Conclusion
Fatal food anaphylaxis for a food‐allergic person is rarer than accidental death in the general population.
The CHIME Pulsar Project: System Overview Amiri, M.; Bandura, K. M.; Boyle, P. J. ...
The Astrophysical journal. Supplement series,
07/2021, Letnik:
255, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
We present the design, implementation, and performance of the digital pulsar observing system constructed for the Canadian Hydrogen Intensity Mapping Experiment (CHIME). Using accelerated ...computing, this system processes independent, digitally steered beams formed by the CHIME correlator to simultaneously observe up to 10 radio pulsars and transient sources. Each of these independent streams is processed by the CHIME/Pulsar back-end system, which can coherently dedisperse, in real time, up to dispersion measure values of 2500 pc cm
−3
. The tracking beams and real-time analysis system are autonomously controlled by a priority-based algorithm that schedules both known sources and positions of interest for observation with observing cadences as rapid as 1 day. Given the distribution of known pulsars and radio-transient sources and the dynamic scheduling, the CHIME/Pulsar system can monitor 400–500 positions once per sidereal day and observe most sources with declinations greater than −20° once every ∼4 weeks. We also discuss the extensive science program enabled through the current modes of data acquisition for CHIME/Pulsar that centers on timing and searching experiments.
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