3,667 research outputs found

    Modelling gas around galaxy pairs and groups using the Q0107 quasar triplet

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    We examine to what extent disc and outflow models can reproduce observations of H I gas within a few virial radii of galaxies in pairs and groups. Using highly sensitive HST/COS and FOS spectra of the Q0107 quasar triplet covering Ly α for z≲1, as well as a deep galaxy redshift survey including VIMOS, DEIMOS, GMOS, and MUSE data, we test simple disc and outflow models against the H I absorption along three lines-of-sight (separated by 200–500 kpc) through nine galaxy groups in this field. These can be compared with our previous results in which these models can often be fit to the absorption around isolated galaxies. Our models can reproduce ≈ 75 per cent of the 28 identified absorption components within 500 km s−1 of a group galaxy, so most of the H I around groups is consistent with a superposition of the CGM of the individual galaxies. Gas stripped in interactions between galaxies may be a plausible explanation for some of the remaining absorption, but neither the galaxy images nor the galaxy and absorber kinematics provide clear evidence of such stripped material, and these unexplained absorbers do not preferentially occur around close pairs of galaxies. We find H I column densities typically higher than at similar impact parameters around isolated galaxies (≈ 2.5σ), as well as more frequent detections of O VI than around isolated galaxies (30 per cent of sightlines to 7 per cent)

    Signatures of extended discs and outflows in the circumgalactic medium using the Q0107 quasar triplet

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    We use H I absorption along the lines-of-sight to the Q0107 quasar triplet in order to model potential disc and outflow structures in the circumgalactic medium of intervening galaxies at z ≲ 1, as well as the intergalactic medium on scales of up to a few virial radii. We consider a sample of twelve isolated galaxies in the Q0107 field with position angles and inclinations measured from HST imaging as well as redshifts from our spectroscopic surveys, alongside 27 detected Ly α absorbers within 500 km s−1 of these galaxies. Building on previous work showing increased incidence of absorption close to the projected major and minor axes, we use model rotating discs and bi-conical outflows in attempting to reproduce the observed absorption. Requiring these models to match absorption in multiple lines-of-sight provides additional constraints over single-sightline observations. We identify four possible outflows with velocities ∼100 km s−1, two of which extend to or beyond the virial radius, with a variety of opening angles. Two galaxies have nearby co-rotating absorbers with rotation velocities ≲ vvir, that may probe disc-like structures, and we can rule out a disc/outflow origin for a further ten absorbers. These indicate that outflowing and co-rotating structures can extend to large scales but are either not ubiquitous, or do not always produce detectable Ly α. In some cases, disc models are successful even close to the minor axis of the galaxy, and some of our model outflows exhibit wide opening angles. These results imply that purely geometrical cuts are not sufficient to distinguish between discs and outflows in single line-of-sight studies

    Surficial Geologic Map of the Constantine 7.5-Minute Quadrangle, Kentucky

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    The Constantine 7.5-minute quadrangle is located west of Elizabethtown along the boundary of Hardin and Breckinridge Counties. The quadrangle lies along the northern section of the Dripping Springs Escarpment, which separates the Mammoth Cave Plateau and Pennyroyal regions of the Mississippian Sinkhole Plain physiographic province (McFarlan, 1943). Topography is mostly characterized by high-elevation plateaus, ridges, and knobs of the Mammoth Cave Plateau (up to 919 ft), which have been intensely dissected by the Rough River and its tributaries (down to 516 ft). A small area of the Pennyroyal extends into the eastern part of the quadrangle, which is marked by a relatively low-relief, low-elevation sinkhole plain. Sable (1964) mapped the bedrock geology of the quadrangle, which was later digitized by Conley (2002). Bedrock throughout the quadrangle is mapped as Upper Mississippian. A series of northeast-trending faults through the southeastern half of the quadrangle (splays from the Rough Creek Fault System) have created a series of horst and graben structures that control bedrock exposure and stream incision. The oldest bedrock lithologic unit mapped is the Ste. Genevieve Limestone, which is overlain by the Paoli Limestone; both are exposed in the Pennyroyal region in the eastern part of the quadrangle and northwest of the fault system. The Mooretown Formation and Beaver Bend Limestone are mostly exposed along steep slopes above the Paoli Limestone; a large area of Mooretown Formation is locally exposed in a broad plain situated northwest of the fault system in the center of the quadrangle. The Sample Sandstone overlies the Beaver Bend Limestone and covers the largest portion of plateaus and ridgetops in the area, mostly northwest of the fault system. The Reelsville Limestone and Golconda Formation overlie the Sample Sandstone and are exposed in isolated knobs and ridges northwest of the fault system, and extensively in the southeastern section of the quadrangle, where they are overlain by the Hardinsburg Sandstone, the youngest unit mapped in the Constantine quadrangle.https://uknowledge.uky.edu/kgs_cr/1002/thumbnail.jp

    Report: Telepaediatrics in Rural and Remote Australia and Canada

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    Rural and remote communities in Australia and Canada experience barriers to accessing healthcare services (1). These barriers are especially pronounced when attempting to access more specialized health care services, such as paediatric (2–4). Both countries have implemented programs that aim to bridge the gap between rural communities and specialized healthcare. One such service is telepaediatrics. Telepaediatrics, as part of telehealth, refers to any paediatric health-related service, network, or medical tool that transmits voice, data, images and information through telecommunication programs as part of providing health services (5–7). Telehealth services are ideal because they remove the need to relocate the rural patient to urban specialist sites (5–7). In a WHO survey (2010), 60% of member countries had telehealth services in place but only 30% of these programs were implemented as part of routin

    Hybrid coracoclavicular and acromioclavicular reconstruction in chronic acromioclavicular joint dislocations yields good functional and radiographic results

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    Purpose Optimal treatment of chronic unstable acromioclavicular (AC) joint dislocations (stage 3-5 according the Rockwood classification) is still debated. Anatomic coracoclavicular (CC) reconstruction is a reliable option in terms of two-dimensional radiographic reduction, clinical outcomes, and return to sports, but there remain concerns regarding anterior-posterior stability of the AC joint with CC ligament reconstruction alone. The aim of the present study was to describe the mid-term results of a new hybrid technique with CC and AC ligament reconstruction for chronic AC joint dislocations. Methods Twenty-two patients surgically treated for chronic AC joint dislocations (grade 3 to 5) were retrospectively reviewed. All patients were assessed before surgery and at final follow-up with the Constant-Murley score (CMS) and the American Shoulder and Elbow Surgeons (ASES) score. The CC vertical distance (CCD) and the CCD ratio (affected side compared to unaffected side) were measured on Zanca radiographs preoperatively, at 6 months postop and at final follow-up. The same surgical technique consisting in a primary fixation with a suspensory system, coracoclavicular ligaments reconstruction with a double loop of autologous gracilis and acromioclavicular ligaments reconstruction with autologous coracoacromial ligament was performed in all cases. Results Twenty-two shoulders in 22 patients (19 males and 3 females) were evaluated with a mean age of 34.4 +/- 9 years at the time of surgery. The mean interval between the injury and surgery was 53.4 +/- 36.7 days. The mean duration of postoperative follow-up was 49.9 +/- 11.8 months. According to the Rockwood classification, there were 5 (22.6%) type-III and 17 (77.2%) type-V dislocations. Mean preoperative ASES and CMS were 54.4 +/- 7.6 and 64.6 +/- 7.2, respectively. They improved to 91.8 +/- 2.3 (p = 0.0001) and 95.2 +/- 3.1 (p = 0.0001), respectively at final FU. The mean preoperative CCD was 22.4 +/- 3.2 mm while the mean CCD ratio was 2.1 +/- 0.1. At final FU, the mean CCD was 11.9 +/- 1.4 mm (p = 0.002) and the mean CCD ratio was 1.1 +/- 0.1 (p = 0.009). No recurrence of instability was observed. One patient developed a local infection and four patients referred some shoulder discomfort. Heterotopic ossifications were observed in three patients. Conclusions The optimal treatment of chronic high-grade AC joint dislocations requires superior-inferior and anterior-posterior stability to ensure good clinical outcomes and return to overhead activities or sports. The present hybrid technique of AC and CC ligaments reconstruction showed good clinical and radiographic results and is a reliable an alternative to other reported techniques

    Enantiocomplementary Epoxidation Reactions Catalyzed by an Engineered Cofactor‐Independent Non‐Natural Peroxygenase

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    Peroxygenases are heme-dependent enzymes that use peroxide-borne oxygen to catalyze a wide range of oxyfunctionalization reactions. Herein, we report the engineering of an unusual cofactor-independent peroxygenase based on a promiscuous tautomerase that accepts different hydroperoxides (t-BuOOH and H2O2) to accomplish enantiocomplementary epoxidations of various α,β-unsaturated aldehydes (citral and substituted cinnamaldehydes), providing access to both enantiomers of the corresponding α,β-epoxy-aldehydes. High conversions (up to 98 %), high enantioselectivity (up to 98 % ee), and good product yields (50–80 %) were achieved. The reactions likely proceed via a reactive enzyme-bound iminium ion intermediate, allowing tweaking of the enzyme's activity and selectivity by protein engineering. Our results underscore the potential of catalytic promiscuity for the engineering of new cofactor-independent oxidative enzymes
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