The Ediacaran Period: A New Addition to the Geologic Time Scale

The International Union of Geological Sciences has approved a new addition to the geologic time scale: the Ediacaran Period. The Ediacaran is the first Proterozoic period to be recognized on the basis of chronostratigraphic criteria and the first internationally ratified, chronostratigraphically defined period of any age to be introduced in more than a century. In accordance with procedures established by the International Commission on Stratigraphy, the base of the Ediacaran Period is defined by a Global Stratotype Section and Point (GSSP) placed at the base of the Nuccaleena Formation cap carbonate directly above glacial diamictites and associated facies at Enorama Creek in the Flinders Ranges of South Australia. Its top is defined by the initial GSSP of the Cambrian Period. The new Ediacaran Period encompasses a distinctive interval of Earth history that is bounded both above and below by equally distinctive intervals. Both chemostratigraphic and biostratigraphic data indicate that the subdivision of the period into two or more series is feasible, and this should be a primary objective of continuing work by the Ediacaran Subcommission of the ICS

Group 2 Innate Lymphoid Cells Are Redundant in Experimental Renal Ischemia-Reperfusion Injury.

Acute kidney injury (AKI) can be fatal and is a well-defined risk factor for the development of chronic kidney disease. Group 2 innate lymphoid cells (ILC2s) are innate producers of type-2 cytokines and are critical regulators of homeostasis in peripheral organs. However, our knowledge of their function in the kidney is relatively limited. Recent evidence suggests that increasing ILC2 numbers by systemic administration of recombinant interleukin (IL)-25 or IL-33 protects against renal injury. Whilst ILC2s can be induced to protect against ischemic- or chemical-induced AKI, the impact of ILC2 deficiency or depletion on the severity of renal injury is unknown. Firstly, the phenotype and location of ILC2s in the kidney was assessed under homeostatic conditions. Kidney ILC2s constitutively expressed high levels of IL-5 and were located in close proximity to the renal vasculature. To test the functional role of ILC2s in the kidney, an experimental model of renal ischemia-reperfusion injury (IRI) was used and the severity of injury was assessed in wild-type, ILC2-reduced, ILC2-deficient, and ILC2-depleted mice. Surprisingly, there were no differences in histopathology, collagen deposition or mRNA expression of injury-associated (Lcn2), inflammatory (Cxcl1, Cxcl2, and Tnf) or extracellular matrix (Col1a1, Fn1) factors following IRI in the absence of ILC2s. These data suggest the absence of ILC2s does not alter the severity of renal injury, suggesting possible redundancy. Therefore, other mechanisms of type 2-mediated immune cell activation likely compensate in the absence of ILC2s. Hence, a loss of ILC2s is unlikely to increase susceptibility to, or severity of AKI

Novel Pressure Induced Structural Phase Transition in AgSbTe2_{2}

We report a novel high pressure structural sequence for the functionally graded thermoelectric, narrow band gap semiconductor AgSbTe$_{2}$, using angle dispersive x-ray diffraction in a diamond anvil cell with synchrotron radiation at room temperature. The compound undergoes a B1 to B2 transition; the transition proceeds through an intermediate amorphous phase found between 17-26 GPa that is quenchable down to ambient conditions. The pressure induced structural transition observed in this compound is the first of its type reported in this ternary cubic family, and it is new for the B1-B2 transition pathway reported to date. Density Functional Theory (DFT) calculations performed for the B1 and B2 phases are in good agreement with the experimental results.Comment: 4 pages, 3 figure

A Submillimetre Survey of the Hubble Deep Field: Unveiling Dust-Enshrouded Star Formation in the Early Universe

The advent of sensitive sub-mm array cameras now allows a proper census of dust-enshrouded massive star-formation in very distant galaxies, previously hidden activity to which even the deepest optical images are insensitive. We present the deepest sub-mm survey, taken with the SCUBA camera on the James Clerk Maxwell Telescope (JCMT) and centred on the Hubble Deep Field (HDF). The high source density on this image implies that the survey is confusion-limited below a flux density of 2 mJy. However within the central 80 arcsec radius independent analyses yield 5 reproducible sources with S(850um) > 2 mJy which simulations indicate can be ascribed to individual galaxies. These data lead to integral source counts which are completely inconsistent with a no evolution model, whilst the combined brightness of the 5 most secure sources in our map is sufficient to account for 30-50% of the previously unresolved sub-mm background, and statistically the entire background is resolved at about the 0.3 mJy level. Four of the five brightest sources appear to be associated with galaxies which lie in the redshift range 2 < z < 4. With the caveat that this is a small sample of sources detected in a small survey area, these submm data imply a star-formation density over this redshift range that is at least five times higher than that inferred from the rest-frame ultraviolet output of HDF galaxies.Comment: to appear in the proceedings of `The Birth of Galaxies', Xth Rencontres de Blois, 4 pages, 1 postscript figure, uses blois.sty (included

Incidence and Prevalence of Chronic Obstructive Pulmonary Disease among Aboriginal Peoples in Alberta, Canada

Background Chronic obstructive pulmonary disease (COPD) is a major respiratory disorder, largely caused by smoking that has been linked with large health inequalities worldwide. There are important gaps in our knowledge about how COPD affects Aboriginal peoples. This retrospective cohort study assessed the epidemiology of COPD in a cohort of Aboriginal peoples relative to a non-Aboriginal cohort. Methods We used linkage of administrative health databases in Alberta (Canada) from April 1, 2002 to March 31, 2010 to compare the annual prevalence, and the incidence rates of COPD between Aboriginal and non-Aboriginal cohorts aged 35 years and older. Poisson regression models adjusted the analysis for important sociodemographic factors. Results Compared to a non-Aboriginal cohort, prevalence estimates of COPD from 2002 to 2010 were 2.3 to 2.4 times greater among Registered First Nations peoples, followed by the Inuit (1.86 to 2.10 times higher) and the Métis (1.59 to 1.67 times higher). All Aboriginal peoples had significantly higher COPD incidence rates than the non-Aboriginal group (incidence rate ratio [IRR]: 2.1; 95% confidence interval [CI]: 1.97, 2.27). COPD incidence rates were higher in First Nation peoples (IRR: 2.37; 95% CI: 2.19, 2.56) followed by Inuit (IRR: 1.92; 95% CI: 1.64, 2.25) and Métis (IRR: 1.49; 95% CI: 1.32, 1.69) groups. Conclusions We found a high burden of COPD among Aboriginal peoples living in Alberta; a province with the third largest Aboriginal population in Canada. Altogether, the three Aboriginal peoples groups have higher prevalence and incidence of COPD compared to a non-Aboriginal cohort. The condition affects the three Aboriginal groups differently; Registered First Nations and Inuit have the highest burden of COPD. Reasons for these differences should be further explored within a framework of social determinants of health to help designing interventions that effectively influence modifiable COPD risk factors in each of the Aboriginal groups

Conformationally rigid pyrazoloquinazoline α-amino acids: one- and two-photon induced fluorescence

The synthesis and photophysical properties of a new class of α-amino acid bearing a rigid pyrazoloquinazoline chromophore are described. Confromational constraint of the amino acid side-chains resulted in high emission quantum yields, while the demonstration of two-photon-induced fluorescence via near-IR excitation signifies their potential for sensitive bioimaging applications

Phosphonated Lower-Molecular-Weight Polyethyleneimines as Oilfield Scale Inhibitors: An Experimental and Theoretical Study

For many years, amino methylenephosphonate (-CH2-N-PO3H2)-based scale inhibitors (SIs) have been deployed for preventing various scales in the oil and gas industry, particularly for squeeze treatment applications. However, this class of phosphonate inhibitors showed several limitations related to environmental concerns and compatibility with brine solutions. The low toxicity of low-molecular-weight polyethyleneimine (LMW-PEI) encouraged us to phosphonate a series of branched and linear PEIs via the Moedritzer–Irani reaction. The phosphonated polyethyleneimine PPEIs are branched PPEI-600, branched PPEI-1200, branched PPEI-2000, and linear PPEI-5000. The newly synthesized PPEIs (branched and linear) were screened for calcium carbonate and barium sulfate utilizing a high-pressure dynamic tube-blocking rig at 100 °C and 80 bar. Moreover, we report the compatibility activity of all PPEIs with various concentrations of calcium ions (up to 10000 ppm). The morphology of the calcium carbonate and barium sulfate scale crystals in the absence and presence of linear PPEI-5000 was also investigated under static conditions using scanning electron microscopy (SEM). The obtained results showed that all branched and linear PPEIs gave moderate calcite and barite inhibition activities. It was also found that all branched PPEIs gave moderate to poor calcium compatibility at high dosages of calcium ions (1000–10 000 ppm). Interestingly, linear PPEI-5000 displayed superior compatibility properties at high dosages of SI (up to 50 000 ppm) and high concentrations of Ca2+ ions (up to 10 000 ppm). Furthermore, field emission scanning electron microscopy analysis confirmed that the crystal shapes of CaCO3 and BaSO4 mineral scales are greatly changed in the presence of linear PPEI-5000. At high dosages of linear PPEI-5000 SI (100 ppm), the CaCO3 crystals are completely converted from cubic-shaped blocks (blank calcite) into long cluster shapes. Density functional theory (DFT) simulations reveal favorable interactions of PPEI polymers with the two mineral facets (calcite and barite) with more affinity toward the calcite surface. PPEI with more phosphonate groups exhibits affinities comparable to the commercial-scale inhibitors. The high density of the phosphonate groups on the branched PPEI and its strong affinity toward calcium ions explain its poor calcium compatibility. The polymer flocculation and sluggish barite kinetics are the potential reasons for its low performance against thepublishedVersio

Combined micro-Fourier transform infrared (FTIR) spectroscopy and micro-Raman spectroscopy of Proterozoic acritarchs: A new approach to Paleobiology

Abstract Micro-scale analytical techniques permit correlation of chemistry with morphology of individual Proterozoic acritarchs (organic-walled microfossils), and thus provide new approaches for elucidating their biological affinities. A combination of micro-Fourier transform infrared (FTIR) spectroscopy and laser micro-Raman spectroscopy was used to investigate the organic structure and composition of individual acritarchs. Well preserved Neoproterozoic acritarchs from the Tanana Formation, Australia (ca. 590-565 Ma), and Mesoproterozoic acritarchs from the Roper Group (1.5-1.4 Ga), Australia, and Ruyang Group, China (1.4-1.3 Ga, age poorly resolved but certainly &gt;1000 Ma and &lt;1625 Ma) have thermal maturities that range from immature to oil window. FTIR spectra of Tanarium conoideum from the Tanana Formation contain intense aliphatic C H stretching bands in the 2900 cm −1 region relative to the C C aromatic ring stretching band at 1600 cm −1 . This FTIR spectrum is consistent with the FTIR spectra obtained from algaenans isolated from extant chlorophyte and eustigmatophyte microalgae. FTIR spectra of Leiosphaeridia sp. from the Tanana Formation contain a less intense aliphatic C H stretching band relative to the C C aromatic ring stretching band. By comparison, the spectra acquired from the Mesoproterozoic acritarchs were dominated by C C aromatic ring stretching bands at 1600 cm −1 relative to moderate-weak CH 3 terminal groups (1345 cm −1 ), C H aliphatic stretching (3000-2700 cm −1 ), and C O (1710 cm −1 ), although some differences in biopolymer composition occurred between species. Curve-fitting of the aliphatic C H x stretching region provides greater insight into the aliphatic structures of the acritarchs. The CH 2 /CH 3 intensity ratio can be used to assess the relative chain length and degree of branching. Organic material in the Tanarium conoideum consists of straight long chain hydrocarbons, while the other acritarchs contain hydrocarbons consisting of short chains that are highly branched. In this study it was found that Raman spectroscopy does not provide additional information about biopolymer composition of Proterozoic acritarchs, but rather offers complementary data regarding the aromaticity and degree of saturation of the macromolecular structure of acritarch cysts

Inhibition of beta-Catenin/CREB Binding Protein Signaling Attenuates House Dust Mite-Induced Goblet Cell Metaplasia in Mice

Excessive mucus production is a major feature of allergic asthma. Disruption of epithelial junctions by allergens such as house dust mite (HDM) results in the activation of β-catenin signaling, which has been reported to stimulate goblet cell differentiation. β-catenin interacts with various co-activators including CREB binding protein (CBP) and p300, thereby regulating the expression of genes involved in cell proliferation and differentiation, respectively. We specifically investigated the role of the β-catenin/CBP signaling pathway in goblet cell metaplasia in a HDM-induced allergic airway disease model in mice using ICG-001, a small molecule inhibitor that blocks the binding of CBP to β-catenin. Female 6- 8-week-old BALB/c mice were sensitized to HDM/saline on days 0, 1, and 2, followed by intranasal challenge with HDM/saline with or without subcutaneous ICG-001/vehicle treatment from days 14 to 17, and samples harvested 24 h after the last challenge/treatment. Differential inflammatory cells in bronchoalveolar lavage (BAL) fluid were enumerated. Alcian blue (AB)/Periodic acid–Schiff (PAS) staining was used to identify goblet cells/mucus production, and airway hyperresponsiveness (AHR) was assessed using invasive plethysmography. Exposure to HDM induced airway inflammation, goblet cell metaplasia and increased AHR, with increased airway resistance in response to the non-specific spasmogen methacholine. Inhibition of the β-catenin/CBP pathway using treatment with ICG-001 significantly attenuated the HDM-induced goblet cell metaplasia and infiltration of macrophages, but had no effect on eosinophils, neutrophils, lymphocytes or AHR. Increased β-catenin/CBP signaling may promote HDM-induced goblet cell metaplasia in mice

CfAIR2: Near Infrared Light Curves of 94 Type Ia Supernovae

CfAIR2 is a large homogeneously reduced set of near-infrared (NIR) light curves for Type Ia supernovae (SN Ia) obtained with the 1.3m Peters Automated InfraRed Imaging TELescope (PAIRITEL). This data set includes 4607 measurements of 94 SN Ia and 4 additional SN Iax observed from 2005-2011 at the Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona. CfAIR2 includes JHKs photometric measurements for 88 normal and 6 spectroscopically peculiar SN Ia in the nearby universe, with a median redshift of z~0.021 for the normal SN Ia. CfAIR2 data span the range from -13 days to +127 days from B-band maximum. More than half of the light curves begin before the time of maximum and the coverage typically contains ~13-18 epochs of observation, depending on the filter. We present extensive tests that verify the fidelity of the CfAIR2 data pipeline, including comparison to the excellent data of the Carnegie Supernova Project. CfAIR2 contributes to a firm local anchor for supernova cosmology studies in the NIR. Because SN Ia are more nearly standard candles in the NIR and are less vulnerable to the vexing problems of extinction by dust, CfAIR2 will help the supernova cosmology community develop more precise and accurate extragalactic distance probes to improve our knowledge of cosmological parameters, including dark energy and its potential time variation.Comment: 31 pages, 15 figures, 10 tables. Accepted to ApJS. v2 modified to more closely match journal versio