The incidence and properties of present-day dwarf galaxies hosting massive black holes (BHs) can provide important constraints on the origin of high-redshift BH seeds. Here we present high-resolution ...X-ray and radio observations of the low-metallicity, star-forming, dwarf-galaxy system Mrk 709 with the Chandra X-ray Observatory and the Karl G. Jansky Very Large Array. These data reveal spatially coincident hard X-ray and radio point sources with luminosities suggesting the presence of an accreting massive BH (M sub(BH) ~ 10 super(5-7) M sub(middot in circle)). Based on imaging from the Sloan Digital Sky Survey (SDSS), we find that Mrk 709 consists of a pair of compact dwarf galaxies that appear to be interacting with one another. The position of the candidate massive BH is consistent with the optical center of the southern galaxy (Mrk 709 S), while no evidence for an active BH is seen in the northern galaxy (Mrk 709 N). We derive stellar masses of Mlow * ~ 2.5 x 10 super(9)M sub(middot in circle) and Mlow * ~ 1.1 x 10 super(9) M sub(middot in circle) for Mrk 709 S and Mrk 709 N, respectively, and present an analysis of the SDSS spectrum of the BH host Mrk 709 S. At a metallicity of just ~10% solar, Mrk 709 is among the most metal-poor galaxies with evidence for an active galactic nucleus. Moreover, this discovery adds to the growing body of evidence that massive BHs can form in dwarf galaxies and that deep, high-resolution X-ray and radio observations are ideally suited to reveal accreting massive BHs hidden at optical wavelengths.
Mammalian ceramide synthases 1 to 6 (CerS1–6) generate Cer in an acyl-CoA-dependent manner, and expression of individual CerS has been shown to enhance the synthesis of ceramides with particular acyl ...chain lengths. However, the contribution of each CerS to steady-state levels of specific Cer species has not been evaluated. We investigated the knockdown of individual CerS in the MCF-7 human breast adenocarcinoma cell line by using small-interfering RNA (siRNA). We found that siRNA-induced downregulation of each CerS resulted in counter-regulation of nontargeted CerS. Additionally, each CerS knockdown produced unique effects on the levels of multiple sphingolipid species. For example, downregulation of CerS2 decreased very long-chain Cer but increased levels of CerS4, CerS5, and CerS6 expression and upregulated long-chain and medium-long-chain sphingolipids. Conversely, CerS6 knockdown decreased C16:0-Cer but increased CerS5 expression and caused non-C16:0 sphingolipids to be upregulated. Knockdown of individual CerS failed to decrease total sphingolipids or upregulate sphingoid bases. Treatment with siRNAs targeting combined CerS, CerS2, CerS5, and CerS6, did not change overall Cer or sphingomyelin mass but caused upregulation of dihydroceramide and hexosylceramide and promoted endoplasmic reticulum stress. These data suggest that sphingolipid metabolism is robustly regulated by both redundancy in CerS-mediated Cer synthesis and counter-regulation of CerS expression.
We examined the effects of different ethanol and iso-butanol blends on the gaseous and particulate emissions from two passenger cars equipped with spark ignition direct injection engines and with one ...spray-guided and one wall-guided configuration. Both vehicles were tested over triplicate FTP (Federal Test Procedure) and UC (Unified Cycles) using a chassis dynamometer. Emissions of THC (total hydrocarbons), NMHC (non-methane hydrocarbons), and CO (carbon monoxide) reduced with increasing oxygen content in the blend for some of the vehicle/fuel combinations, whereas NOx (nitrogen oxide) emissions did not show strong fuel effects. Formaldehyde and acetaldehyde were the main carbonyls in the exhaust, with the higher ethanol blends showing higher acetaldehyde emissions during the cold-start. For butyraldehyde emissions, both vehicles showed some increases with different butanol blends when compared to ethanol blends, but not for all cases. The higher ethanol and butanol blends showed reductions in PM (particulate mass), number, and soot mass emissions. Particulate emissions were significantly affected by the fuel injection design, with the wall-guided vehicle producing higher mass and number emissions compared to the spray-guided vehicle. Particle size was influenced by ethanol and iso-butanol content, with higher alcohol blends showing lower accumulation mode particles than the baseline fuel.
•THC, NMHC, CO, CO2, and CH4 emissions reduced with higher alcohol blends.•Butyraldehyde emissions increased with higher butanol blends relative to ethanol fuels.•Wall-guided fueling showed significantly higher PM than spray-guided fueling.•PM and particle number emissions trended lower with higher ethanol and butanol blends.•Higher oxygen/lower aromatic content blends reduced accumulation mode particles.
ABSTRACT
We present a new catalogue of radio sources in the face-on spiral galaxy M83. Radio observations taken in 2011, 2015, and 2017 with the Australia Telescope Compact Array at 5.5 and 9 GHz ...have detected 270 radio sources. Although a small number of these sources are background extragalactic sources, most are either H ii regions or supernova remnants (SNRs) within M83 itself. Three of the six historical supernovae are detected, as is the very young remnant that had been identified in a recent study, which is likely the result of a supernova that exploded in the last ∼100 yr but was missed. All of these objects are generally fading with time. Confusion limits our ability to measure the radio emission from a number of the SNRs in M83, but 64 were detected in unconfused regions, and these have the approximate power-law luminosity function that has been observed in other galaxies. The SNRs in M83 are systematically smaller in diameter and brighter than those that have been detected at radio wavelengths in M33. A number of the radio sources are coincident with X-ray sources in M83; most of these coincident sources turn out to be SNRs. Our dual frequency observations are among the most sensitive to date for a spiral galaxy outside the Local Group; despite this we were not able to place realistic constraints on the spectral indices, and as a result, it was not possible to search for SNRs based on their radio properties alone.
Nearby blue compact dwarf (BCD) galaxies are arguably our best local analogs of galaxies in the earlier universe that may host relics of black hole (BH) seeds. Here we present high-resolution Chandra ...X-ray Observatory and Karl G. Jansky Very Large Array observations of five nearby BCDs with stellar masses of less than the Small Magellanic Cloud (M ∼ 107-108.4 M ). We search for signatures of accreting massive BHs at X-ray and radio wavelengths, which are more sensitive to lower BH accretion rates than optical searches. We detect a total of 10 hard X-ray sources and 10 compact radio sources at luminosities consistent with star-formation-related emission. We find one case of a spatially coincident X-ray and radio source within the astrometric uncertainties. If the X-ray and radio emission are indeed coming from the same source, the origin of the radiation is plausibly from an active massive BH with log (MBH/M ) ∼ 4.8 1.1. However, given that the X-ray and radio emission are also coincident with a young star cluster complex, we consider the combination of an X-ray binary and a supernova remnant (or H ii region) a viable alternative explanation. Overall, we do not find compelling evidence for active massive BHs in our target BCDs, which on average have stellar masses more than an order of magnitude lower than previous samples of dwarf galaxies found to host massive BHs. Our results suggest that moderately accreting massive BHs in BCDs are not so common as to permit unambiguous detection in a small sample.
Objective
Objective measurement of pre-operative severity is important to optimize evidence-based practices given that the wide spectrum of presentation likely influences outcomes. The purpose of ...this study was to determine the correlation of objective measures of form with a subjective standard of cleft severity.
Design
3D images were ranked according to severity of nasal deformity by 7 cleft surgeons so that the mean rank could be used as the severity standard.
Patients
45 patients with unilateral cleft lip and 5 normal control subjects.
Interventions
Each image was assessed using traditional anthropometric analysis, 3D landmark displacements, and shape-based analysis to produce 81 indices for each subject.
Main Outcome
The correlation of objective measurements with the clinical severity standard.
Results
Lateral deviation of subnasale from midline was the best predictor of severity (0.86). Other strongly-correlated anthropometric measurements included columellar angle, nostril width ratio, and lateral lip height ratio (0.72, 0.80, 0.79). Almost all shape-based measurements had tight correlation with the severity standard, however, dorsum deviation and point difference nasolabial symmetry were the most predictive (0.84, 0.82).
Conclusions
Quantitative measures of severity transcend cleft type and can be used to grade clinical severity. Lateral deviation of subnasale was the best measure of severity and may be used as a surrogate of uncoupled premaxillary growth; it should be recorded as an index of pre-operative severity with every cleft lip repair. The correlation of other measures evaluated clarify treatment priorities and could potentially be used to grade outcomes.
Hybrid engine technology is a potentially important strategy for reduction of tailpipe greenhouse gas (GHG) emissions and other pollutants that is now being implemented for off-road construction ...equipment. The goal of this study was to evaluate the emissions and fuel consumption impacts of electric-hybrid excavators using a Portable Emissions Measurement System (PEMS)-based methodology. In this study, three hybrid and four conventional excavators were studied for both real world activity patterns and tailpipe emissions. Activity data was obtained using engine control module (ECM) and global positioning system (GPS) logged data, coupled with interviews, historical records, and video. This activity data was used to develop a test cycle with seven modes representing different types of excavator work. Emissions data were collected over this test cycle using a PEMS. The results indicated the HB215 hybrid excavator provided a significant reduction in tailpipe carbon dioxide (CO2) emissions (from −13 to −26%), but increased diesel particulate matter (PM) (+26 to +27%) when compared to a similar model conventional excavator over the same duty cycle.
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•The activities for 4 excavators were characterized using engine control module (ECM) and GPS data, videos, and interviews.•The activity measurements were used to develop duty cycles for repeatable comparisons.•A total 7 excavators were evaluated for emissions and fuel consumption over the developed duty cycles using PEMS.•The hybrid showed reductions in CO2 emissions (−16%), butincreased PM (+26%) and NOx emissions (+1%).
Abstract Black hole (BH) X-ray binaries (XRBs) are ideal targets to study the connection between accretion inflow and jet outflow. Here we present quasi-simultaneous, multiwavelength observations of ...the Galactic BH system MAXI J1820+070, throughout its 2018–2019 outburst. Our data set includes coverage from the radio through X-ray bands from 17 different instruments/telescopes, and encompasses 19 epochs over a 7 month period, resulting in one of the most well-sampled multiwavelength data sets of a BH XRB outburst to date. With our data, we compile and model the broadband spectra of this source using a phenomenological model that includes emission from the jet, a companion star, and an accretion flow. This modeling allows us to track the evolution of the spectral break in the jet spectrum, a key observable that samples the jet launching region. We find that the spectral break location changes over at least ≈3 orders of magnitude in electromagnetic frequency over this period. Using these spectral break measurements, we link the full cycle of jet behavior, including the rising, quenching, and reignition, to the changing accretion flow properties as the source evolves through its different accretion states. Our analysis shows consistent jet behavior with other sources in similar phases of their outbursts, reinforcing the idea that jet quenching and recovery may be a global feature of BH XRB systems in outburst. Our results also provide valuable evidence supporting a close connection between the geometry of the inner accretion flow and the base of the jet.
ABSTRACT
Infrared interferometry is a new frontier for precision ground-based observing, with new instrumentation achieving milliarcsecond (mas) spatial resolutions for faint sources, along with ...astrometry on the order of 10 microarcseconds (μas). This technique has already led to breakthroughs in the observations of the supermassive black hole at the Galactic centre and its orbiting stars, active galactic nucleus, and exo-planets, and can be employed for studying X-ray binaries (XRBs), microquasars in particular. Beyond constraining the orbital parameters of the system using the centroid wobble and spatially resolving jet discrete ejections on mas scales, we also propose a novel method to discern between the various components contributing to the infrared bands: accretion disc, jets, and companion star. We demonstrate that the GRAVITY instrument on the Very Large Telescope Interferometer should be able to detect a centroid shift in a number of sources, opening a new avenue of exploration for the myriad of transients expected to be discovered in the coming decade of radio all-sky surveys. We also present the first proof-of-concept GRAVITY observation of a low-mass XRB transient, MAXI J1820+070, to search for extended jets on mas scales. We place the tightest constraints yet via direct imaging on the size of the infrared emitting region of the compact jet in a hard state XRB.
Cross-sectional imaging is important in the assessment of transmural inflammation in Crohn’s disease (CD). Small bowel involvement is often more extensive in pediatric CD, requiring a panentering ...measuring tool. We undertook to develop a magnetic resonance enterography (MRE)-based index that would measure inflammation in all segments of the intestine, without rectal contrast.
Children with CD underwent ileocolonoscopy and MRE and half were prospectively followed for 18 months when MRE was repeated. Item generation and reduction were performed by a Delphi panel of pediatric radiologists, a systematic literature review, a cross-sectional study of 48 MREs, and a steering committee. Formatting and weighting were performed using multivariate modeling adjusted by a steering committee. MREs were read locally and centrally. Reliability, validity, and responsiveness were determined using several clinimetric and psychometric approaches.
Thirty items were initially generated and reduced to 5 using regression analysis on 159 MREs: wall thickness, wall diffusion weighted imaging, ulcerations, mesenteric edema, and comb sign. In the validation cohort of 81 MREs, the weighted global PICMI correlated well with the radiologist global assessment (r = 0.85; P < .001) and with the simple endoscopic score in a subsample with ileocolonic disease (r = 0.63; P < .001). Interobserver and test-retest reliability were high (interclass correlation coefficients, 0.84; 95% confidence interval CI, 0.79–0.87; and 0.81, 95% CI, 0.65–0.90, respectively; both P < .001). Excellent responsiveness was found at repeated visits (n = 116 MREs; area under the receiver operating characteristic curve 0.96; 95% CI, 0.93–0.99). Transmural healing was defined as PICMI ≤10 and response as a change of >20 points with excellent discriminative validity (area under the receiver operating characteristic curve = 0.96; 95% CI, 0.93–0.99).
The PICMI is a valid, reliable, and responsive index for assessing transmural inflammation in pediatric CD. It scores the entire bowel length and does not require intravenous contrast or rectal enema and, therefore, is suitable for use in children. (ClinicalTrials.gov, Number: NCT01881490.)
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We have developed a validated score, called the Pediatric Inflammatory Crohn’s Magnetic Resonance Enterography Index, which quantifies the degree of inflammation in the bowel of children with Crohn’s disease, as measured using magnetic resonance imaging of the bowel.
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