Transmission of Zika virus (ZIKV) in the Americas was first confirmed in May 2015 in northeast Brazil. Brazil has had the highest number of reported ZIKV cases worldwide (more than 200,000 by 24 ...December 2016) and the most cases associated with microcephaly and other birth defects (2,366 confirmed by 31 December 2016). Since the initial detection of ZIKV in Brazil, more than 45 countries in the Americas have reported local ZIKV transmission, with 24 of these reporting severe ZIKV-associated disease. However, the origin and epidemic history of ZIKV in Brazil and the Americas remain poorly understood, despite the value of this information for interpreting observed trends in reported microcephaly. Here we address this issue by generating 54 complete or partial ZIKV genomes, mostly from Brazil, and reporting data generated by a mobile genomics laboratory that travelled across northeast Brazil in 2016. One sequence represents the earliest confirmed ZIKV infection in Brazil. Analyses of viral genomes with ecological and epidemiological data yield an estimate that ZIKV was present in northeast Brazil by February 2014 and is likely to have disseminated from there, nationally and internationally, before the first detection of ZIKV in the Americas. Estimated dates for the international spread of ZIKV from Brazil indicate the duration of pre-detection cryptic transmission in recipient regions. The role of northeast Brazil in the establishment of ZIKV in the Americas is further supported by geographic analysis of ZIKV transmission potential and by estimates of the basic reproduction number of the virus.
The yellow fever virus (YFV) epidemic in Brazil is the largest in decades. The recent discovery of YFV in Brazilian
species mosquitos highlights a need to monitor the risk of reestablishment of urban ...YFV transmission in the Americas. We use a suite of epidemiological, spatial, and genomic approaches to characterize YFV transmission. We show that the age and sex distribution of human cases is characteristic of sylvatic transmission. Analysis of YFV cases combined with genomes generated locally reveals an early phase of sylvatic YFV transmission and spatial expansion toward previously YFV-free areas, followed by a rise in viral spillover to humans in late 2016. Our results establish a framework for monitoring YFV transmission in real time that will contribute to a global strategy to eliminate future YFV epidemics.
Knowledge of abundance, trends and distribution of cetacean populations is needed to inform marine conservation efforts, ecosystem models and spatial planning. We compiled a geo-spatial database of ...published data on cetacean abundance from dedicated visual line-transect surveys and encoded >1100 abundance estimates for 47 species from 430 surveys conducted worldwide from 1975-2005. Our subsequent analyses revealed large spatial, temporal and taxonomic variability and gaps in survey coverage. With the exception of Antarctic waters, survey coverage was biased toward the northern hemisphere, especially US and northern European waters. Overall, <25% of the world's ocean surface was surveyed and only 6% had been covered frequently enough (≥ 5 times) to allow trend estimation. Almost half the global survey effort, defined as total area (km(2)) covered by all survey study areas across time, was concentrated in the Eastern Tropical Pacific (ETP). Neither the number of surveys conducted nor the survey effort had increased in recent years. Across species, an average of 10% of a species' predicted range had been covered by at least one survey, but there was considerable variation among species. With the exception of three delphinid species, <1% of all species' ranges had been covered frequently enough for trend analysis. Sperm whales emerged from our analyses as a relatively data-rich species. This is a notoriously difficult species to survey visually, and we use this as an example to illustrate the challenges of using available data from line-transect surveys for the detection of trends or for spatial planning. We propose field and analytical methods to fill in data gaps to improve cetacean conservation efforts.
The bottlenose dolphin, Tursiops truncatus, is one of very few animals that, through vocal learning, can invent novel acoustic signals and copy whistles of conspecifics. Furthermore, receivers can ...extract identity information from the invented part of whistles. In captivity, dolphins use such signature whistles while separated from the rest of their group. However, little is known about how they use them at sea. If signature whistles are the main vehicle to transmit identity information, then dolphins should exchange these whistles in contexts where groups or individuals join. We used passive acoustic localization during focal boat follows to observe signature whistle use in the wild. We found that stereotypic whistle exchanges occurred primarily when groups of dolphins met and joined at sea. A sequence analysis verified that most of the whistles used during joins were signature whistles. Whistle matching or copying was not observed in any of the joins. The data show that signature whistle exchanges are a significant part of a greeting sequence that allows dolphins to identify conspecifics when encountering them in the wild.
Aims
. In the framework of the multi-wavelength and very long baseline interferometry (VLBI) monitoring program TANAMI (Tracking Active Nuclei with Austral Milliarcsecond Interferometry), we study ...the evolution of the parsec-scale radio emission in radio galaxies in the southern hemisphere and their relationship to the
γ
-ray properties of the sources. Our study investigates systematically, for the first time, the relationship between the two energy regimes in radio galaxies. In this first paper, we focus on
Fermi
-LAT-detected sources.
Methods
. The TANAMI program monitors a large sample of radio-loud AGN at 8.4 GHz and 22.3 GHz with the Australian long baseline array (LBA) and associated telescopes in Antarctica, Chile, New Zealand and South Africa. We performed a kinematic analysis for five
γ
-ray detected radio galaxies using multi-epoch 8.4 GHz VLBI images, deriving limits on intrinsic jet parameters such as speed and viewing angle. We analyzed 103 months of
Fermi
-LAT data in order to study possible connections between the
γ
-ray properties and the pc-scale jets of
Fermi
-LAT-detected radio galaxies, both in terms of variability and average properties. We discuss the individual source results and draw preliminary conclusions on sample properties including published VLBI results from the MOJAVE (Monitoring Of Jets in Active galactic nuclei with VLBA Experiments) survey, with a total of fifteen sources.
Results
. We find that the first
γ
-ray detection of Pictor A might be associated with the passage of a new VLBI component through the radio core, which appears to be a defining feature of high-energy emitting Fanaroff-Riley type II radio galaxies. We detect subluminal parsec-scale jet motions in the peculiar AGN PKS 0521−36, and we confirm the presence of fast
γ
-ray variability in the source down to timescales of six hours, which is not accompanied by variations in the VLBI jet. We robustly confirm the presence of significant superluminal motion, up to
β
app
∼ 3, in the jet of the TeV radio galaxy PKS 0625−35. Our VLBI results constrain the jet viewing angle to be
θ
< 53°, allowing for the possibility of a closely aligned jet. Finally, by analyzing the first pc-scale multi-epoch images of the prototypical compact symmetric object (CSO) PKS 1718−649, we place an upper limit on the separation speed between the two mini-lobes. This in turn allows us to derive a lower limit on the age of the source.
Conclusions.
We can draw some preliminary conclusions on the relationship between pc-scale jets and
γ
-ray emission in radio galaxies, based on
Fermi
-LAT-detected sources with available multi-epoch VLBI measurements. We find that the VLBI core flux density correlates with the
γ
-ray flux, as seen in blazars. On the other hand, the
γ
-ray luminosity does not show any dependence on the core brightness temperature and core dominance, which are two common indicators of jet Doppler boosting. This seems to indicate that
γ
-ray emission in radio galaxies is not driven by orientation-dependent effects, as in blazars, in accordance with the unified model of jetted AGN.
The IceCube Collaboration has announced the discovery of a neutrino flux in excess of the atmospheric background. Owing to the steeply falling atmospheric background spectrum, events at PeV energies ...most likely have an extraterrestrial origin. We present the multiwavelength properties of the six radio-brightest blazars that are positionally coincident with these events using contemporaneous data of the TANAMI blazar sample, including high-resolution images and spectral energy distributions. Assuming the X-ray to γ-ray emission originates in the photoproduction of pions by accelerated protons, the integrated predicted neutrino luminosity of these sources is high enough to explain the two detected PeV events.
Most dietary interventions have metabolic effects in the short term, but long-term effects may require dietary fat changes to influence body composition and insulin action. This study assessed the ...effect of sustained high polyunsaturated fatty acids (PUFA) intake through walnut consumption on metabolic outcomes in type II diabetes.
Fifty overweight adults with non-insulin-treated diabetes (mean age 54+/-8.7 years) were randomized to receive low-fat dietary advice +/-30 g per day walnuts targeting weight maintenance (around 2000 kcal, 30% fat) for 1 year. Differences between groups were assessed by changes in anthropometric values (body weight, body fat, visceral adipose tissue) and clinical indicators of diabetes over treatment time using the general linear model.
The walnut group consumed significantly more PUFA than the control (P=0.035), an outcome attributed to walnut consumption (contributing 67% dietary PUFA at 12 months). Most of the effects were seen in the first 3 months. Despite being on weight maintenance diets, both groups sustained a 1-2 kg weight loss, with no difference between groups (P=0.680). Both groups showed improvements in all clinical parameters with significant time effects (P<0.004), bar triacylglycerol levels, but these were just above normal to begin with. The walnut group produced significantly greater reductions in fasting insulin levels (P=0.046), an effect seen largely in the first 3 months.
Dietary fat can be manipulated with whole foods such as walnuts, producing reductions in fasting insulin levels. Long-term effects are also apparent but subject to fluctuations in dietary intake if not of the disease process.
Abstract Silicic calderas can evacuate 100 to >1000 km3 of rhyolitic products in a matter of days to months, leading to questions on pre-eruptive melt generation and accumulation. Whereas silicic ...plutonic units may provide information on the igneous evolution of crystal-mush bodies, their connection with volcanic units remains enigmatic. In the Ivrea–Verbano Zone of the southern Alps, the plumbing system of a Permian rhyolitic caldera is exposed to a depth of about 25 km in tilted crustal blocks. The upper-crustal segment of this magmatic system (also known as the Sesia Magmatic System) is represented by the Valle Mosso pluton (VMP). The VMP is an ∼260 km3 composite silicic intrusion ranging from quartz-monzonite to high-silica leucogranite (∼67–77 wt% SiO2), which intrudes into roughly coeval rhyolitic products of the >15 km diameter Sesia Caldera. In the caldera field, the emplacement of a large, crystal-rich rhyolite ignimbrite(s) (>400 km3) is followed by eruption of minor volumes (1–10 km3) of crystal-poor rhyolite. Here, we compare silicic plutonic and volcanic units of the Sesia Magmatic System through a combination of geochemical (X-ray fluorescence, inductively coupled plasma mass spectrometry and electron microprobe analyses) and petrological (rhyolite-MELTS, trace element and diffusion modeling) tools to explore their connection. Textural and compositional features shared by both VMP and crystal-rich ignimbrites imply thermal rejuvenation of crystal-mush as the mechanism to create large volumes of eruptible rhyolitic magma. Bulk-rock composition of crystal-rich rhyolite erupted during the caldera collapse overlaps that of the bulk VMP. Quartz and plagioclase from these two units show resorbed cores and inverse zoning, with Ti- and anorthite-rich rims, respectively. This indicates crystallization temperatures in rims >60 °C higher than in cores (780–820 versus ∼720 °C), if temperature is the sole parameter responsible for zonation, suggesting heating and partial dissolution of the crystal-framework. Decrease in crystallinity associated with thermal energy input was calculated through rhyolite-MELTS and indicates lowering of the mush crystal fraction below the rheological lock-up threshold, which probably promoted eruptive activity. Also, after the climatic eruption, Si-rich melts in the Sesia Magmatic System were produced by extraction of interstitial melt from un-erupted, largely crystalline mush. Regarding both textures and chemical variations, we interpret the deep quartz-monzonite unit of the VMP as a compacted silicic cumulate. Fractionated melts extracted from this unit were emplaced as a leucogranite cupola atop the VMP, generating the final internal architecture of the silicic intrusion, or alternatively erupted as minor post-caldera, crystal-poor rhyolite. Ti-in-quartz diffusion profiles in thermally rejuvenated units of the Sesia Magmatic System demonstrate that the process of reheating, mobilization and eruption of crystal-mush took place rapidly (c. 101–102 years). A protracted cooling history is instead recorded in the diffusion timescales of quartz from the silicic cumulate units (c. 104–106 years). These longer timescales encompass the duration of evolved melt extraction from the cumulate residue. We argue that the VMP preserves a complex record of pre-eruptive processes, which span mechanisms and timescales universally identified in volcanic systems and are consistent with recently proposed numerical models.
Context.
With the emergence of very high energy astronomy (VHE;
E >
100 GeV), new open questions were presented to astronomers studying the multi-wavelength emission from blazars. Answers to these ...open questions, such as the Doppler crisis, and finding the location of the high-energy activity have eluded us thus far. Recently, quasi-simultaneous multi-wavelength monitoring programs have shown considerable success in investigating blazar activity.
Aims.
Such quasi-simultaneous observations across the electromagnetic spectrum became possible thanks to the launch of the
Fermi
Gamma-ray Space Telescope in 2008. In addition, with very long baseline interferometry (VLBI) observations, we can resolve the central parsec region of active galactic nuclei (AGN) and compare morphological changes to γ-ray activity in order to study high-energy-emitting blazars. To achieve our goals, we need sensitive, long-term VLBI monitoring of a complete sample of VHE-detected AGN.
Methods.
We performed VLBI observations of TeV-detected AGN and high-likelihood neutrino associations as of December of 2021 with the Long Baseline Array (LBA) and other southern-hemisphere radio telescopes at 2.3 GHz.
Results.
In this paper, we present first light TANAMI
S
-band images, focusing on the TeV-detected subsample of the full TANAMI sample. In addition to these VHE-detected sources, we show images of two flux density calibrators and two additional sources included in the observations. We study the redshift, 0.1–100 GeV photon flux, and
S
-band core brightness temperature distributions of the TeV-detected objects, and find that flat-spectrum radio quasars and low-synchrotron-peaked sources on average show higher brightness temperatures than high-synchrotron-peaked BL Lacs. Sources with bright GeV
γ
-ray emission also show higher brightness temperature values than
γ
-low sources.
Conclusions.
Long-term monitoring programs are crucial for studying the multiwavelength properties of AGN. With the successful detection of even the faintest sources, with flux densities below 50 mJy, future work will entail kinematic analysis and spectral studies both at 2.3 and 8.4 GHz to investigate the connection between the radio and
γ
-ray activity of these objects.
ABSTRACT
We report the detection of new 12.178, 12.229, 20.347, and 23.121 GHz methanol masers in the massive star-forming region G358.93−0.03, which are flaring on similarly short time-scales (days) ...as the 6.668 GHz methanol masers also associated with this source. The brightest 12.178 GHz channel increased by a factor of over 700 in just 50 d. The masers found in the 12.229 and 20.347 GHz methanol transitions are the first ever reported and this is only the fourth object to exhibit associated 23.121 GHz methanol masers. The 12.178 GHz methanol maser emission appears to have a higher flux density than that of the 6.668 GHz emission, which is unusual. No associated near-infrared flare counterpart was found, suggesting that the energy source of the flare is deeply embedded.
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