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Biological Indicators for Fecal Pollution Detection and Source Tracking: A Review
Fecal pollution, commonly detected in untreated or less treated sewage, is associated with health risks (e.g., waterborne diseases and antibiotic resistance dissemination), ecological issues (e.g., release of harmful gases in fecal sludge composting, proliferative bacterial/algal growth due to high nutrient loads) and economy losses (e.g., reduced aqua farm harvesting). Therefore, the discharge of untreated domestic sewage to the environment and its agricultural reuse are growing concerns. The goals of fecal pollution detection include fecal waste source tracking and identifying the presence of pathogens, therefore assessing potential health risks. This review summarizes available biological fecal indicators focusing on host specificity, degree of association with fecal pollution, environmental persistence, and quantification methods in fecal pollution assessment. The development of practical tools is a crucial requirement for the implementation of mitigation strategies that may help confine the types of host-specific pathogens and determine the source control point, such as sourcing fecal wastes from point sources and nonpoint sources. Emerging multidisciplinary bacterial enumeration platforms are also discussed, including individual working mechanisms, applications, advantages, and limitations.
Journal Article
Intense star formation within resolved compact regions in a galaxy at z = 2.3
Distant star formation
The individual star-forming regions of the massive galaxies in the early Universe, at redshifts of around
z
= 2, are beyond the reach of even the largest of today's telescopes. But with help from gravitational lensing by a massive intervening galaxy cluster, brightening the image 32-fold and making it look larger, intense star formation has been observed in the submillimetre galaxy SMMJ2135-0102 at redshift
z
= 2.3259. The results reveal luminosity densities comparable to those of the dense cores of giant molecular clouds in the local Universe, suggesting that the underlying physics of star formation is similar to that of nearby galaxies, though the regions in the distant galaxies are about 100 times larger and 10
7
times more luminous overall.
Massive galaxies in the early Universe have been shown to be forming stars at high rates. Probing the properties of individual star-forming regions is beyond the resolution and sensitivity of existing telescopes. Here, however, observations are reported of the galaxy SMMJ2135–0102 at redshift
z
=2.3259, which has been gravitationally magnified by a factor of 32 by a galaxy cluster lens in the foreground. The physics underlying star formation here is similar to that in local galaxies, but the energetics are very different.
Massive galaxies in the early Universe have been shown to be forming stars at surprisingly high rates
1
,
2
,
3
. Prominent examples are dust-obscured galaxies which are luminous when observed at sub-millimetre wavelengths and which may be forming stars at a rate of 1,000 solar masses (
M
⊙
) per year
4
,
5
,
6
,
7
. These intense bursts of star formation are believed to be driven by mergers between gas-rich galaxies
8
,
9
. Probing the properties of individual star-forming regions within these galaxies, however, is beyond the spatial resolution and sensitivity of even the largest telescopes at present. Here we report observations of the sub-millimetre galaxy SMMJ2135-0102 at redshift
z
= 2.3259, which has been gravitationally magnified by a factor of 32 by a massive foreground galaxy cluster lens. This magnification, when combined with high-resolution sub-millimetre imaging, resolves the star-forming regions at a linear scale of only 100 parsecs. We find that the luminosity densities of these star-forming regions are comparable to the dense cores of giant molecular clouds in the local Universe, but they are about a hundred times larger and 10
7
times more luminous. Although vigorously star-forming, the underlying physics of the star-formation processes at
z
≈ 2 appears to be similar to that seen in local galaxies, although the energetics are unlike anything found in the present-day Universe.
Journal Article
X-Ray Cavity Dynamics and Their Role in the Gas Precipitation in Planck Sunyaev–Zeldovich (SZ) Selected Clusters
We study active galactic nucleus (AGN) feedback in nearby (z < 0.35) galaxy clusters from the Planck Sunyaev–Zeldovich sample using Chandra observations. This nearly unbiased mass-selected sample includes both relaxed and disturbed clusters and may reflect the entire AGN feedback cycle. We find that relaxed clusters better follow the one-to-one relation of cavity power versus cooling luminosity, while disturbed clusters display higher cavity power for a given cooling luminosity, likely reflecting a difference in cooling and feedback efficiency. Disturbed clusters are also found to contain asymmetric cavities when compared to relaxed clusters, hinting toward the influence of the intracluster medium (ICM) “weather” on the distribution and morphology of the cavities. Disturbed clusters do not have fewer cavities than relaxed clusters, suggesting that cavities are difficult to disrupt. Thus, multiple cavities are a natural outcome of recurrent AGN outbursts. As in previous studies, we confirm that clusters with short central cooling times, t cool, and low central entropy values, K 0, contain warm ionized (10,000 K) or cold molecular (<100 K) gas, consistent with ICM cooling and a precipitation/chaotic cold accretion scenario. We analyzed archival Multi-Unit Spectroscopic Explorer observations that are available for 18 clusters. In 11/18 of the cases, the projected optical line emission filaments appear to be located beneath or around the cavity rims, indicating that AGN feedback plays an important role in forming the warm filaments by likely enhancing turbulence or uplift. In the remaining cases (7/18), the clusters either lack cavities or their association of filaments with cavities is vague, suggesting alternative turbulence-driven mechanisms (sloshing/mergers) or physical time delays are involved.
Journal Article
تاريخ ملك ومملكة الحسين 1892-1999
يتناول كتاب (تاريخ ملك ومملكة الحسين) والذي قام بتأليفه \"رولان دالاس\" في حوالي (304) صفحة من القطع المتوسط، تاريخ الملك \"حسين بن طلال\" وتاريخ الأردن، فكانت حكاية الحسين مذهلة ومثيرة. أصبح ملكا في 2 مايو 1953، وواجه أول أزمة سياسية في 4 مايو 1954 حين أقال رئيس وزرائه وهو في التاسعة عشر من عمره. أدى طوال خمسة عقود تقريبا دورا أساسيا في شؤون الشرق الأوسط، إلى أن توفي من مرض السرطان سنة 1999، وكان إضافة إلى الملكة إليزابيت، من بين زعماء الدول الأكثر أمدا في السلطة، نجا من عدة محاولات اغتيال وتزوج أربع مرات، مرة من امرأة إنكليزية ومرة من أميركية، كان شخص مزيج من البدو والحضر. فكان رجل استثنائي.
BOOK
Redshift Evolution of the Feedback–Cooling Equilibrium in the Core of 48 SPT Galaxy Clusters: A Joint Chandra–SPT–ATCA Analysis
We analyze the cooling and feedback properties of 48 galaxy clusters at redshifts 0.4 < z < 1.3 selected from the South Pole Telescope (SPT) catalogs to evolve like the progenitors of massive and well-studied systems at z ∼ 0. We estimate the radio power at the brightest cluster galaxy (BCG) location of each cluster from an analysis of Australia Telescope Compact Array data. Assuming that the scaling relation between the radio power and active galactic nucleus (AGN) cavity power P cav observed at low redshift does not evolve with redshift, we use these measurements in order to estimate the expected AGN cavity power in the core of each system. We estimate the X-ray luminosity within the cooling radius L cool of each cluster from a joint analysis of the available Chandra X-ray and SPT Sunyaev–Zel’dovich (SZ) data. This allows us to characterize the redshift evolution of the P cav/L cool ratio. When combined with low-redshift results, these constraints enable investigations of the properties of the feedback–cooling cycle across 9 Gyr of cluster growth. We model the redshift evolution of this ratio measured for cool-core clusters by a log-normal distribution Log - (α+βz,σ2) and constrain the slope of the mean evolution to β = −0.05 ± 0.47. This analysis improves the constraints on the slope of this relation by a factor of two. We find no evidence of redshift evolution of the feedback–cooling equilibrium in these clusters, which suggests that the onset of radio-mode feedback took place at an early stage of cluster formation. High values of P cav/L cool are found at the BCG location of noncool-core clusters, which might suggest that the timescales of the AGN feedback cycle and the cool core–noncool core transition are different. This work demonstrates that the joint analysis of radio, SZ, and X-ray data solidifies the investigation of AGN feedback at high redshifts.
Journal Article
Transverse Demagnetization Dynamics of a Unitary Fermi Gas
Understanding the quantum dynamics of strongly interacting fermions is a problem relevant to diverse forms of matter, including high-temperature superconductors, neutron stars, and quark-gluon plasma. An appealing benchmark is offered by cold atomic gases in the unitary limit of strong interactions. Here, we study the dynamics of a transversely magnetized unitary Fermi gas in an inhomogeneous magnetic field. We observe the demagnetization of the gas, caused by diffusive spin transport. At low temperatures, the diffusion constant saturates to the conjectured quantum-mechanical lower bound ≃ ħ/m, where m is the particle mass. The development of pair correlations, indicating the transformation of the initially noninteracting gas toward a unitary spin mixture, is observed by measuring Tan's contact parameter.
Journal Article