79 research outputs found
Human population as a key driver of biochemical burden in an inter-city system:Implications for One Health concept
This paper tests the hypothesis that human population and city function are key drivers of biochemical burden in an inter-city system, which can be used to inform One Health actions as it enables a holistic understanding of city's metabolism encompassing all of the activities of a city in a single model: from lifestyle choices, through to health status and exposure to harmful chemicals as well as effectiveness of implemented management strategies. Chemical mining of wastewater for biophysico-chemical indicators (BCIs) was undertaken to understand speciation of BCIs in the context of geographical as well as community-wide socioeconomic factors. Spatiotemporal variabilities in chemical and biological target groups in the studied inter-city system were observed. A linear relationship (R2 > 0.99) and a strong positive correlation between most BCIs and population size (r > 0.998, p < 0.001) were observed which provides a strong evidence for the population size as a driver of BCI burden. BCI groups that are strongly correlated with population size and are intrinsic to humans’ function include mostly high usage pharmaceuticals that are linked with long term non-communicable conditions (NSAIDs, analgesics, cardiovascular, mental health and antiepileptics) and lifestyle chemicals. These BCIs can be used as population size markers. BCIs groups that are produced as a result of a specific city's function (e.g. industry presence and occupational exposure or agriculture) and as such are not correlated with population size include: pesticides, PCPs and industrial chemicals. These BCIs can be used to assess city's function, such as occupational exposure, environmental or food exposure, and as a proxy of community-wide health. This study confirmed a strong positive correlation between antibiotics (ABs), population size and antibiotic resistance genes (ARGs). This confirms the population size and AB usage as the main driver of AB and ARG levels and provides an opportunity for interventions aimed at the reduction of AB usage to reduce AMR. Holistic evaluation of biophysicochemical fingerprints (BCI burden) of the environment and data triangulation with socioeconomic fingerprints (indices) of tested communities are required to fully embrace One Health concept.</p
Diagnosing Down-the-Drain Disposal of Unused Pharmaceuticals at a River Catchment Level:Unrecognized Sources of Environmental Contamination That Require Nontechnological Solutions
Down-the-drain
disposal of pharmaceuticals remains an overlooked
and unrecognized source of environmental contamination that requires
nontechnological “at-source” solutions. Monitoring of
31 pharmaceuticals over 7 days in five wastewater treatment plants
(WWTPs) serving five cities in South-West UK revealed down-the-drain
codisposal of six pharmaceuticals to three WWTPs (carbamazepine and
propranolol in city A, sildenafil in city B, and diltiazem, capecitabine,
and sertraline in city D), with a one-off record codisposal of estimated
253 pills = 40 g of carbamazepine and estimated 96 pills = 4 g of
propranolol in city A accounting for their 10- and 3-fold respective
increases in wastewater daily loads. Direct disposal of pharmaceuticals
was found to affect the efficiency of wastewater treatment with much
higher pharmaceutical removal (decrease in daily load) during “down-the-drain
disposal” days. This is due to lack of conjugated glucuronide
metabolites that are cleaved during “consumption-only”
days, with the release of a parent pharmaceutical counterbalancing
its removal. Higher removal of pharmaceuticals during down-the-drain
disposal days reduced pharmaceutical loads reaching receiving environment,
albeit with significant levels remaining. The estimated daily loads
in receiving water downstream from a discharge point accounted for
13.8 ± 3.4 and 2.1 ± 0.2 g day–1 of carbamazepine
and propranolol, respectively, during consumption-only days and peaked
at 20.9 g day–1 (carbamazepine) and 4.6 g day–1 (propranolol) during down-the-drain disposal days.
Actions are needed to reduce down-the-drain disposal of pharmaceuticals.
Our recent work indicated that down-the-drain disposal of pharmaceuticals
doubled since the last study in 2005, which may be due to the lack
of information and messaging that informs people to dispose of unused
medicines at pharmacies. Media campaigns that inform the public of
how to safely dispose of medicines are key to improving rates of return
and reducing pharmaceutical waste in the environment. The environment
is a key motivator for returning unused medicines to a pharmacy and
so messaging should highlight environmental risks associated with
improper disposal
The Bullet cluster at its best: weighing stars, gas and dark matter
We present a new strong lensing mass reconstruction of the Bullet cluster (1E
0657-56) at z=0.296, based on WFC3 and ACS HST imaging and VLT/FORS2
spectroscopy. The strong lensing constraints underwent substantial revision
compared to previously published analysis, there are now 14 (six new and eight
previously known) multiply-imaged systems, of which three have
spectroscopically confirmed redshifts (including one newly measured from this
work). The reconstructed mass distribution explicitly included the combination
of three mass components: i) the intra-cluster gas mass derived from X-ray
observation, ii) the cluster galaxies modeled by their fundamental plane
scaling relations and iii) dark matter. The model that includes the
intra-cluster gas is the one with the best Bayesian evidence. This model has a
total RMS value of 0.158" between the predicted and measured image positions
for the 14 multiple images considered. The proximity of the total RMS to
resolution of HST/WFC3 and ACS (0.07-0.15" FWHM) demonstrates the excellent
precision of our mass model. The derived mass model confirms the spatial offset
between the X-ray gas and dark matter peaks. The fraction of the galaxy halos
mass to total mass is found to be f_s=11+/-5% for a total mass of 2.5+/-0.1 x
10^14 solar mass within a 250 kpc radial aperture.Comment: Accepted by A&A 15 pages, 12 figure
Maternal influences on oral and faecal microbiota maturation in neonatal calves in beef and dairy production systems
Background The dam is considered an important source of microbes for the calf; consequently, the development of calf microbiota may vary with farming system due to differences between the contact the calf has with the dam. The objective of this study was to characterise the early changes in the composition of oral and faecal microbiota in beef and dairy calves (N = 10) using high-throughput sequencing of the 16S rRNA gene. The microbiota of calves was compared to selected anatomical niches on their dams which were likely to contribute to the vertical transfer of microbes. Results A total of 14,125 amplicon sequence variants (ASVs) were identified and taxonomically assigned. The oral microbiota of calves and their dams were composed of more similar microbes after the first 4 weeks of life than immediately after calving. The faecal microbiota of four-week old calves was composed of microbes which were more similar to those found in the oral microbiota of calves and adult cows than the faecal microbiota of adult cows. Specific ASVs were identified in the oral microbiota of four-week old calves that were also present in cow niches at calving, whereas very few ASVs were present in the calf faecal microbiota at four-weeks of age were present in any adult cow niche at calving. These results were observed in both beef and dairy calves. Conclusions We did not observe any marked differences in the maturation of the oral and faecal microbiota between beef or dairy calves, despite dairy calves having very limited contact with their dam. This suggests the development of gastrointestinal microbiota in calves may not be affected by continued vertical transmission of microbes from the dam. Although the calf faecal microbiota changed over the first four-weeks of life, it was composed of microbes which were phylogenetically closer to those in the oral microbiota of calves and adult cows than the faeces of adult cows. There was little evidence of persistent microbial seeding of the calf faeces from anatomical niches on the cow at calving in either beef or dairy animals
Strong size evolution of the most massive galaxies since z~2
Using the combined capabilities of the large near-infrared Palomar/DEEP-2
survey, and the superb resolution of the ACS HST camera, we explore the size
evolution of 831 very massive galaxies (M*>10^{11}h_{70}^{-2}M_sun) since z~2.
We split our sample according to their light concentration using the Sersic
index n. At a given stellar mass, both low (n2.5)
concentrated objects were much smaller in the past than their local massive
counterparts. This evolution is particularly strong for the highly concentrated
(spheroid-like) objects. At z~1.5, massive spheroid-like objects were a factor
of 4(+-0.4) smaller (i.e. almost two orders of magnitudes denser) than those we
see today. These small sized, high mass galaxies do not exist in the nearby
Universe, suggesting that this population merged with other galaxies over
several billion years to form the largest galaxies we see today.Comment: MNRAS in press, 13 pages, 11 figures. Data Table will be published in
its integrity in the MNRAS online versio
A high prevalence of blaOXA-48 in Klebsiella (Raoultella) ornithinolytica and related species in hospital wastewater in South West England
Klebsiella species occupy a wide range of environmental and animal niches, and occasionally cause opportunistic infections that are resistant to multiple antibiotics. In particular, Klebsiella pneumoniae (Kpne) has gained notoriety as a major nosocomial pathogen, due principally to the rise in non-susceptibility to carbapenems and other beta-lactam antibiotics. Whilst it has been proposed that the urban water cycle facilitates transmission of pathogens between clinical settings and the environment, the level of risk posed by resistant Klebsiella strains in hospital wastewater remains unclear. We used whole genome sequencing (WGS) to compare Klebsiella species in contemporaneous samples of wastewater from an English hospital and influent to the associated wastewater treatment plant (WWTP). As we aimed to characterize representative samples of Klebsiella communities, we did not actively select for antibiotic resistance (other than for ampicillin), nor for specific Klebsiella species. Two species, Kpne and K. (Raoultella) ornithinolytica (Korn), were of equal dominance in the hospital wastewater, and four other Klebsiella species were present in low abundance in this sample. In contrast, despite being the species most closely associated with healthcare settings, Kpne was the dominant species within the WWTP influent. In total, 29 % of all isolates harboured the blaOXA-48 gene on a pOXA-48-like plasmid, and these isolates were almost exclusively recovered from the hospital wastewater. This gene was far more common in Korn (68 % of isolates) than in Kpne (3.4 % of isolates). In general plasmid-borne, but not chromosomal, resistance genes were significantly enriched in the hospital wastewater sample. These data implicate hospital wastewater as an important reservoir for antibiotic-resistant Klebsiella, and point to an unsuspected role of species within the Raoultella group in the maintenance and dissemination of plasmid-borne blaOXA-48. This article contains data hosted by Microreact.</p
A high prevalence of bla (OXA-48) in Klebsiella (Raoultella) ornithinolytica and related species in hospital wastewater in South West England
Klebsiella species occupy a wide range of environmental and animal niches, and occasionally cause opportunistic infections that are resistant to multiple antibiotics. In particular, Klebsiella pneumoniae (Kpne) has gained notoriety as a major nosocomial pathogen, due principally to the rise in non-susceptibility to carbapenems and other beta-lactam antibiotics. Whilst it has been proposed that the urban water cycle facilitates transmission of pathogens between clinical settings and the environment, the level of risk posed by resistant Klebsiella strains in hospital wastewater remains unclear. We used whole genome sequencing (WGS) to compare Klebsiella species in contemporaneous samples of wastewater from an English hospital and influent to the associated wastewater treatment plant (WWTP). As we aimed to characterize representative samples of Klebsiella communities, we did not actively select for antibiotic resistance (other than for ampicillin), nor for specific Klebsiella species. Two species, Kpne and K. (Raoultella) ornithinolytica (Korn), were of equal dominance in the hospital wastewater, and four other Klebsiella species were present in low abundance in this sample. In contrast, despite being the species most closely associated with healthcare settings, Kpne was the dominant species within the WWTP influent. In total, 29 % of all isolates harboured the bla(OXA-48) gene on a pOXA-48-like plasmid, and these isolates were almost exclusively recovered from the hospital wastewater. This gene was far more common in Korn (68 % of isolates) than in Kpne (3.4 % of isolates). In general plasmid-borne, but not chromosomal, resistance genes were significantly enriched in the hospital wastewater sample. These data implicate hospital wastewater as an important reservoir for antibiotic-resistant Klebsiella, and point to an unsuspected role of species within the Raoultella group in the maintenance and dissemination of plasmid- borne bla(OXA-48). This article contains data hosted by Microreact.Peer reviewe
A population of luminous accreting black holes with hidden mergers
Major galaxy mergers are thought to play an important part in fuelling the
growth of supermassive black holes. However, observational support for this
hypothesis is mixed, with some studies showing a correlation between merging
galaxies and luminous quasars and others showing no such association. Recent
observations have shown that a black hole is likely to become heavily obscured
behind merger-driven gas and dust, even in the early stages of the merger, when
the galaxies are well separated (5 to 40 kiloparsecs). Merger simulations
further suggest that such obscuration and black-hole accretion peaks in the
final merger stage, when the two galactic nuclei are closely separated (less
than 3 kiloparsecs). Resolving this final stage requires a combination of
high-spatial-resolution infrared imaging and high-sensitivity hard-X-ray
observations to detect highly obscured sources. However, large numbers of
obscured luminous accreting supermassive black holes have been recently
detected nearby (distances below 250 megaparsecs) in X-ray observations. Here
we report high-resolution infrared observations of hard-X-ray-selected black
holes and the discovery of obscured nuclear mergers, the parent populations of
supermassive-black-hole mergers. We find that obscured luminous black holes
(bolometric luminosity higher than 2x10^44 ergs per second) show a significant
(P<0.001) excess of late-stage nuclear mergers (17.6 per cent) compared to a
sample of inactive galaxies with matching stellar masses and star formation
rates (1.1 per cent), in agreement with theoretical predictions. Using
hydrodynamic simulations, we confirm that the excess of nuclear mergers is
indeed strongest for gas-rich major-merger hosts of obscured luminous black
holes in this final stage.Comment: To appear in the 8 November 2018 issue of Nature. This is the
authors' version of the wor
The Rise and Fall of Passive Disk Galaxies: Morphological Evolution Along the Red Sequence Revealed by COSMOS
The increasing abundance of passive "red-sequence" galaxies since z=1-2 is
mirrored by a coincident rise in the number of galaxies with spheroidal
morphologies. In this paper, however, we show that in detail the correspondence
between galaxy morphology and color is not perfect, providing insight into the
physical origin of this evolution. Using the COSMOS survey, we study a
significant population of red sequence galaxies with disk-like morphologies.
These passive disks typically have Sa-Sb morphological types with large bulges,
but they are not confined to dense environments. They represent nearly one-half
of all red-sequence galaxies and dominate at lower masses (log Mstar < 10)
where they are increasingly disk-dominated. As a function of time, the
abundance of passive disks with log Mstar < 11 increases, but not as fast as
red-sequence spheroidals in the same mass range. At higher mass, the passive
disk population has declined since z~1, likely because they transform into
spheroidals. We estimate that as much as 60% of galaxies transitioning onto the
red sequence evolve through a passive disk phase. The origin of passive disks
therefore has broad implications for understanding how star formation shuts
down. Because passive disks tend to be more bulge-dominated than their
star-forming counterparts, a simple fading of blue disks does not fully explain
their origin. We explore several more sophisticated explanations, including
environmental effects, internal stabilization, and disk regrowth during
gas-rich mergers. While previous work has sought to explain color and
morphological transformations with a single process, these observations open
the way to new insight by highlighting the fact that galaxy evolution may
actually proceed through several separate stages.Comment: 16 pages, Accepted version to appear in Ap
Hot gas halos around disk galaxies: Confronting cosmological simulations with observations
Models of disk galaxy formation commonly predict the existence of an extended
reservoir of accreted hot gas surrounding massive spirals at low redshift. As a
test of these models, we use X-ray and H-alpha data of the two massive,
quiescent edge-on spirals NGC 5746 and NGC 5170 to investigate the amount and
origin of any hot gas in their halos. Contrary to our earlier claim, the
Chandra analysis of NGC 5746, employing more recent calibration data, does not
reveal any significant evidence for diffuse X-ray emission outside the optical
disk, with a 3-sigma upper limit to the halo X-ray luminosity of 4e39 erg/s. An
identical study of the less massive NGC 5170 also fails to detect any
extraplanar X-ray emission. By extracting hot halo properties of disk galaxies
formed in cosmological hydrodynamical simulations, we compare these results to
expectations for cosmological accretion of hot gas by spirals. For Milky
Way-sized galaxies, these high-resolution simulations predict hot halo X-ray
luminosities which are lower by a factor of ~2 compared to our earlier results
reported by Toft et al. (2002). We find the new simulation predictions to be
consistent with our observational constraints for both NGC 5746 and NGC 5170,
while also confirming that the hot gas detected so far around more actively
star-forming spirals is in general probably associated with stellar activity in
the disk. Observational results on quiescent disk galaxies at the high-mass end
are nevertheless providing powerful constraints on theoretical predictions, and
hence on the assumed input physics in numerical studies of disk galaxy
formation and evolution.Comment: 16 pages, 8 figures, ApJ accepted. Supersedes arXiv:astro-ph/061089
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