3,035 research outputs found

    Optically gated beating-heart imaging

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    The constant motion of the beating heart presents an obstacle to clear optical imaging, especially 3D imaging, in small animals where direct optical imaging would otherwise be possible. Gating techniques exploit the periodic motion of the heart to computationally "freeze" this movement and overcome motion artefacts. Optically gated imaging represents a recent development of this, where image analysis is used to synchronize acquisition with the heartbeat in a completely non-invasive manner. This article will explain the concept of optical gating, discuss a range of different implementation strategies and their strengths and weaknesses. Finally we will illustrate the usefulness of the technique by discussing applications where optical gating has facilitated novel biological findings by allowing 3D in vivo imaging of cardiac myocytes in their natural environment of the beating heart

    Evolution of star formation in the UKIDSS ultra deep survey field-I. Luminosity functions and cosmic star formation rate out to z = 1.6

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    We present new results on the cosmic star formation history in the Subaru/XMM-Newton Deep Survey (SXDS)-Ultra Deep Survey (UDS) field out to z = 1.6. We compile narrowband data from the Subaru Telescope and the Visible and Infrared Survey Telescope forAstronomy (VISTA) in conjunction with broad-band data from the SXDS and UDS, to makea selection of 5725 emission-line galaxies in 12 redshift slices, spanning 10 Gyr of cosmictime. We determine photometric redshifts for the sample using 11-band photometry, and usea spectroscopically confirmed subset to fine tune the resultant redshift distribution. We usethe maximum-likelihood technique to determine luminosity functions in each redshift slice and model the selection effects inherent in any narrow-band selection statistically, to obviatethe retrospective corrections ordinarily required. The deep narrow-band data are sensitive tovery low star formation rates (SFRs), and allow an accurate evaluation of the faint end slopeof the Schechter function, α We find that a is particularly sensitive to the assumed faintest broad-band magnitude of a galaxy capable of hosting an emission line, and propose thatthis limit should be empirically motivated. For this analysis, we base our threshold on thelimiting observed equivalent widths of emission lines in the local Universe. We compute thecharacteristic SFR of galaxies in each redshift slice, and the integrated SFR density,ρ SFR. Wefind our results to be in good agreement with the literature and parametrize the evolution of the SFR density as ρ SFR α(1 + z)4.58 confirming a steep decline in star formation activity since z ~ 1.6.Peer reviewe

    An extremely high photometric precision in ground-based observations of two transits in the WASP-50 planetary system

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    We present photometric observations of two transits in the WASP-50 planetary system, obtained using the ESO New Technology Telescope and the defocussed-photometry technique. The rms scatters for the two datasets are 258 and 211\,ppm with a cadence of 170 to 200\,s, setting a new record for ground-based photometric observations of a point source. The data were modelled and fitted using the \textsc{prism} and \textsc{gemc} codes, and the physical properties of the system calculated. We find the mass and radius of the hot star to be 0.861\pm 0.057\Msun and 0.855\pm0.019\Rsun, respectively. For the planet we find a mass of 1.437\pm 0.068\Mjup, a radius of 1.138\pm0.026\Rjup and a density of 0.911\pm0.033\pjup. These values are consistent with but more precise than those found in the literature. We also obtain a new orbital ephemeris for the system: T0=BJD/TDB  2 455 558.61237(20) + 1.9550938(13)×E T_0 = {\rm BJD/TDB} \,\, 2\,455\,558.61237 (20) \, + \, 1.9550938 (13) \times E .Comment: 6 Pages, 5 Figures, MNRAS Accepted 5/2/1

    Meadow enriched ACP process algebras

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    We introduce the notion of an ACP process algebra. The models of the axiom system ACP are the origin of this notion. ACP process algebras have to do with processes in which no data are involved. We also introduce the notion of a meadow enriched ACP process algebra, which is a simple generalization of the notion of an ACP process algebra to processes in which data are involved. In meadow enriched ACP process algebras, the mathematical structure for data is a meadow.Comment: 8 pages; correction in Table

    Enhanced recovery following posterior spinal fusion for adolescent idiopathic scoliosis: A medical and economic study in a French private nonprofit pediatric hospital

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    Introduction: Little data exist on the efficacy of enhanced recovery after surgery (ERAS) protocols in patients undergoing posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). Hypothesis: ERAS reduces hospital costs (HC) and length of stay (LOS) without increasing pain or complications. Materials and methods: This was a retrospective comparative medical and economic study of 2 cohorts of patients who underwent PSF for AIS: a prospective group who underwent surgery with an ERAS protocol without a specially assigned care coordinator from 2020 to 2021 (n=30) and a retrospective group (control) who received standard care from 2017 to 2018 (n=30). The key amendments to the ERAS protocol were reduced preoperative investigations, opioid-sparing analgesia, ambulation starting on postoperative day (POD) 1, early resumption of oral diet, and early transition to oral analgesics. Moreover, an intensive care unit (ICU) stay, surgical drainage, and the postoperative CT scan were no longer routine. The discharge criteria were the same for both groups: normal bowel function, independent walking, pain Visual Analog Scale (VAS)<3 without strong opioids, and no signs of complications. The endpoints were: decreased HC (calculated by subtracting the costs of hospital days and complementary exams that were not carried out) and LOS, complications, and postoperative pain according to the VAS on POD 1, POD 3, and discharge. All means were reported with the standard deviation. Results: The mean age of patients undergoing surgery (14.5±1.7 years), sex ratio, curve type according to the Lenke classification, mean Cobb angle (54±12°), and the number of instrumented vertebrae (9±2) were similar in both groups (p>0.5). The HC decreased on average by 3029€ per patient. The mean LOS was 5±0.9 days in the ERAS group versus 6.5±0.6 days in the control group (p<0.001). The VAS scores on POD 1 and POD 3 were lower in the ERAS group. One postoperative complication was noted in each group. Conclusion: Implementing an ERAS protocol without a specifically assigned care coordinator for patients with AIS undergoing PSF significantly decreased HC, LOS, and early postoperative pain. Level of evidence: III; retrospective comparative study

    Surgical Outcomes Following Posterior Spinal Fusion For Adolescent Idiopathic Scoliosis

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    Surgical Outcomes Following Posterior Spinal Fusion for Adolescent Idiopathic ScoliosisWyatt B. David and Michael DiLuna. Section of Pediatric Neurosurgery, Department of Neurosurgery, Yale University, School of Medicine, New Haven, CT. Hospital size has previously been shown to impact outcomes in adult spine surgery. However, there is a paucity of studies assessing the impact of hospital size on outcomes in adolescent spine surgery. Furthermore, gender-based differences have been suggested in disease progression and outcomes of adolescent idiopathic scoliosis (AIS), though only a few studies have investigated these disparities. The aim of this study was to determine the impact of hospital size and gender on length of hospital stay (LOS), complication rate, and costs of admission following posterior spinal fusion (PSF) for AIS. A retrospective cohort study was performed using the 2016-2019 National Inpatient Sample database. Patients 10-17 years old with a primary diagnosis of AIS undergoing elective thoracic PSF were identified using ICD-10-CM diagnostic and procedural coding. Patients were categorized by treating hospital size (Small, Medium, and Large), which incorporates hospital location and teaching status. Patients were also categorized on gender. Patient demographics, comorbidities, intraoperative procedures, postoperative adverse events (AE), length of stay (LOS), discharge disposition and hospital costs were assessed. Multivariate logistic regression analyses were used to identify the impact of gender and hospital size on extended LOS (defined as \u3e75th percentile of LOS), total cost, and postoperative AEs. Of the 17,740 patients identified, 5,165 (29.1%) were in the Small cohort, 3,995 (22.5%) were in the Medium cohort, and 8,580 (48.4%) were in the Large cohort. Patients at Large hospitals generally had more comorbidities than patients at Small and Medium hospitals (p=0.006). Number of thoracic fusion levels were similar among the hospital size cohorts (p=0.648). A greater proportion of patients at Large hospitals experienced ≄1 adverse events (≄1 AE: Small: 23.3% vs. Medium: 32.1% vs. Large: 38%, p=0.009). LOS (p=0.956) and discharge disposition (p=0.380) were similar across all hospitals. Hospital costs were significantly lower at Large, and highest in Medium-size hospitals (Small: 53,381±26,900vs.Medium:53,381±26,900 vs. Medium: 65,445±29,170 vs. Large: $49,732±20,101,
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