52,192 research outputs found
Zentenarfeier bei Aspern, F. X. Matolony Wien
No full textZENTENARFEIER BEI ASPERN, F. X. MATOLONY WIEN
Zentenarfeier bei Aspern, F. X. Matolony Wien ( -
Zentenarfeier bei Aspern, F. X. Matolony Wien
No full textZENTENARFEIER BEI ASPERN, F. X. MATOLONY WIEN
Zentenarfeier bei Aspern, F. X. Matolony Wien ( -
Discovery of an optical counterpart to the hyperluminous X-ray source in ESO 243-49
No full textThe existence of black holes of masses similar to 10(2)-10(5)M(circle dot) has important implications for the formation and evolution of star clusters and supermassive black holes. One of the strongest candidates to date is the hyperluminous X-ray source (HLX1), possibly located in the S0- a galaxy ESO 243-49, but the lack of an identifiable optical counterpart had hampered its interpretation. Using the Magellan telescope, we have discovered an unresolved optical source with R = 23.80 +/- 0.25 mag and V = 24.5 +/- 0.3 mag within HLX1's positional error circle. This implies an average X-ray/optical flux ratio similar to 500. Taking the same distance as ESO 243-49, we obtain an intrinsic brightness M-R = -11.0 +/- 0.3 mag, comparable to that of a massive globular cluster. Alternatively, the optical source is consistent with a main-sequence M star in the Galactic halo (for example an M4.4 star at approximate to 2.5 kpc). We also examined the properties of ESO 243-49 by combining Swift/Ultraviolet/Optical Telescope (UVOT) observations with stellar population modelling. We found that the overall emission is dominated by a similar to 5-Gyr-old stellar population, but the UV emission at approximate to 2000 angstrom is mostly due to ongoing star formation at a rate of similar to 0.03M(circle dot) yr(-1). The UV emission is more intense (at least a 9 sigma enhancement above the mean) north-east of the nucleus, in the same quadrant as HLX1. With the combined optical and X-ray measurements, we put constraints on the nature of HLX1. We rule out a foreground star and a background AGN. Two alternative scenarios are still viable. HLX1 could be an accreting intermediate mass black hole in a star cluster, which may itself be the stripped nucleus of a dwarf galaxy that passed through ESO 243-49, an event which might have caused the current episode of star formation. Or, it could be a neutron star in the Galactic halo, accreting from an M4-M5 donor star
X-ray polarization in relativistic jets
No full textWe investigate the polarization properties of Comptonized X-rays from relativistic jets in active galactic nuclei (AGN) using Monte Carlo simulations. We consider three scenarios commonly proposed for the observed X-ray emission in AGN: Compton scattering of blackbody photons emitted from an accretion disc; scattering of cosmic microwave background (CMB) photons and self-Comptonization of intrinsically polarized synchrotron photons emitted by jet electrons. Our simulations show that for Comptonization of disc and CMB photons, the degree of polarization of the scattered photons increases with the viewing inclination angle with respect to the jet axis. In both cases, the maximum linear polarization is ≈20 per cent. In the case of synchrotron self-Comptonization (SSC), we find that the resulting X-ray polarization depends strongly on the seed synchrotron photon injection site, with typical fractional polarizations P≈ 10–20 per cent when synchrotron emission is localized near the jet base, while P≈ 20–70 per cent for the case of uniform emission throughout the jet. These results indicate that X-ray polarimetry may be capable of providing unique clues to identify the location of particle acceleration sites in relativistic jets. In particular, if synchrotron photons are emitted quasi-uniformly throughout a jet, then the observed degree of X-ray polarization may be sufficiently different for each of the competing X-ray emission mechanisms (synchrotron, SSC or external Comptonization) to determine which is the dominant process. However, X-ray polarimetry alone is unlikely to be able to distinguish between disc and CMB Comptonization
Closed reduction with percutaneous Kirschner wire fixation for delayed treatment of distal humeral epiphyseal fracture separation
No full textAbstract
Background: Fracture separation of the distal humeral epiphysis in children is a relatively uncommon injury, predominantly occurring in children under 3 years. It has a high risk of treatment delays. This study aims to evaluate outcomes in the management of fracture separation of the distal humeral epiphysis treated seven or more days postinitial injury.
Methods: A retrospective analysis was conducted on patients diagnosed with fracture separation of the distal humeral epiphysis between November 2016 and October 2023. Inclusion criteria encompassed patients with delayed presentation of fracture separation of the distal humeral epiphysis who underwent surgical intervention seven or more days following the initial injury. Demographic data were collected, and fractures were categorized using the modified DeLee classification. Plain radiographs facilitated the assessment of the carrying angle and postoperative Baumann angle. Clinical outcomes were evaluated using the Flynn criteria.
Results: The study included 12 patients who met the inclusion criteria. The average age at the time of injury was 1.59 years. According to the modified DeLee system, fracture classification identified one type I fracture, eight type II fractures, and three type III fractures. The average duration from injury to surgery was 11.8 days. The mean surgical
duration was 21.5 min. The average follow-up period was 40.7 months. One patient exhibited cubitus varus development. Based on the Flynn criteria, outcomes were as follows: seven patients had excellent outcomes, four had good outcomes, and one had a poor outcome.
Conclusion: Closed reduction with percutaneous K-wire fixation represents a minimally invasive approach suitable for children diagnosed with fracture separation of the distal humeral epiphysis seven or more days post-initial injury. Most of these patients experienced favorable outcomes.
Level of evidenceAbstract
Background: Fracture separation of the distal humeral epiphysis in children is a relatively uncommon injury, predominantly occurring in children under 3 years. It has a high risk of treatment delays. This study aims to evaluate outcomes in the management of fracture separation of the distal humeral epiphysis treated seven or more days postinitial
injury.
Methods: A retrospective analysis was conducted on patients diagnosed with fracture separation of the distal humeral epiphysis between November 2016 and October 2023. Inclusion criteria encompassed patients with delayed presentation of fracture separation of the distal humeral epiphysis who underwent surgical ntervention seven or more days following the initial injury. Demographic data were collected, and fractures were categorized using the modified
DeLee classification. Plain radiographs facilitated the assessment of the carrying angle and postoperative Baumann angle. Clinical outcomes were evaluated using the Flynn criteria.
Results: The study included 12 patients who met the inclusion criteria. The average age at the time of injury was 1.59 years. According to the modified DeLee system, fracture classification identified one type I fracture, eight type II
fractures, and three type III fractures. The average duration from injury to surgery was 11.8 days. The mean surgical duration was 21.5 min. The average follow-up period was 40.7 months. One patient exhibited cubitus varus development. Based on the Flynn criteria, outcomes were as follows: seven patients had excellent outcomes, four had good outcomes, and one had a poor outcome.
Conclusion: Closed reduction with percutaneous K-wire fixation represents a minimally invasive approach suitable for children diagnosed with fracture separation of the distal humeral epiphysis seven or more days post-initial injury. Most of these patients experienced favorable outcomes.
Level of evidence: [AQ: 4
UvA-DARE (Digital Academic Repository) Link to publication Citation for published version (APA)
No full textThe real role of active-shell in enhancing the luminescence of lanthanides doped nanomaterials Wu, F.; Liu, X.; Kong, X.; Zhang, Y.; Tu, L.; Liu, K.; Song, S.; Zhang, H
On a problem of Wu Wei Chao
No full textAnswering a question posed by Wu Wei Chao [2], we determine all solutions f : ℝ→ℝ of the equationf(x2+y+f(y) ) = f(x)2 + 2y, x,y∈ℝ
Frisilia thapsina Wu and Park 1999
No full text28. Frisilia thapsina Wu and Park, 1999 Korean Jour. Syst. Zool. 15 (1): 1. TL: Sri Lanka, Kal. Dist. Agalawatta. [USNM]. Diagnosis. The species is superficially similar to F. neacantha Wu and Park, but can be distinguished by the male genitalia: valva roundly expanded terminally, juxta not sharply pointed at laterocaudal apices, and aedeagus with weakly sclerotized, quadrate plate, not very narrowed apically. Adult (Fig. 29, paratype in USNM). Wingspan,10.0–12.0 mm. Male genitalia (Figs. 60, 60 a). See Wu and Park (1999: Figs. 1, 2). Female genitalia. See Wu and Park (1999: Fig. 11). Material examined. 18 ♂, 7 Ψ, Kandy, Udawattekelle, 25–26 X 1966 & 31 X 1966, gen. prep. no. CIS- 5198 (♂); 9 ♂, 3 Ψ, same locality, 3–5 XI 1966, 10 XI 1966, & 15–16 XI 1966, gen. prep. no. CIS- 5192 (♂) & 5193 (♂); 1 ♂ (holotype), Kal Dist., Agalawatta, 13–14 X 1976, gen. prep. no. USNM- 88825; 4 ♂, 2 Ψ (paratypes), same data as the holotype; 1 Ψ (paratype), Gal Dist., Kanneliya Jungle, 11–16 I 1975. All types are in the USNM. Distribution. Sri Lanka.Published as part of Park, Kyu-Tek, Wu, Chunseng, Kun, Andras & Sohn, And Jae-Cheon, 2008, A taxonomic review of the genus Frisilia Walker (Lepidoptera: Lecithoceridae), with description of two new species, pp. 1-24 in Zootaxa 1696 on page 14, DOI: 10.5281/zenodo.18072
Nonlinear dynamics of large-scale coherent structures in free shear layers
No full textIt is well known that fully developed turbulent free shear layers exhibit a high degree of order, characterized by large-scale coherent structures, i.e. spanwise vortex rollers. Extensive experimental investigations show that such organised motions bear remarkable resemblance to inviscid instability waves, and their main characteristics, including the length scales, propagation speeds and transverse structure, are reasonably well predicted by inviscid linear stability analysis of the mean flow. In this paper, we present a mathematical theory to describe the nonlinear dynamics of coherent structures. The theory is adapted from the nonlinear non-equilibrium critical-layer approach for laminar-flow instabilities by accounting for (a) the enhanced non-parallelism associated with fast spreading of the mean flow, and (b) the influence of small-scale turbulence on coherent structures. The combination of these factors with nonlinearity leads to an interesting evolution system, consisting of the coupled amplitude and vorticity equations, in which non-parallelism contributes the so-called translational critical-layer effect. Numerical solutions of the evolution system captures vortex roll-up, which is the hallmark of turbulent mixing layer, and the predicted amplitude development closely mimics what was measured in experiments. Key words: turbulence, coherent structures, instability, nonlinearit
Faulhaber's formula, Bernoulli numbers and the equation
No full textIn modern usage the Bernoulli numbers and polynomials follow Euler's approach
and are defined using generating functions. We consider the functional equation
and show that a solution can be derived from Faulhaber's
formula for the sum of powers. We show how these solutions provide a
characterization of Bernoulli numbers and related results.Comment: 4 page
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