3,581 research outputs found
A search for rotating radio transients and fast radio bursts in the Parkes high-latitude pulsar survey
Discoveries of rotating radio transients and fast radio bursts (FRBs) in
pulsar surveys suggest that more of such transient sources await discovery in
archival data sets. Here we report on a single-pulse search for dispersed radio
bursts over a wide range of Galactic latitudes (|b| < ) in data
previously searched for periodic sources by Burgay et al. We re-detected 20 of
the 42 pulsars reported by Burgay et al. and one rotating radio transient
reported by Burke-Spolaor. No FRBs were discovered in this survey. Taking into
account this result, and other recent surveys at Parkes, we corrected for
detection sensitivities based on the search software used in the analyses and
the different backends used in these surveys and find that the all-sky FRB
event rate for sources with a fluence above 4.0 Jy ms at 1.4 GHz to be FRBs day sky, where the
uncertainties represent a confidence interval. While this rate is lower
than inferred from previous studies, as we demonstrate, this combined event
rate is consistent with the results of all systematic FRB searches at Parkes to
date and does not require the need to postulate a dearth of FRBs at
intermediate latitudes.Comment: Accepted, 10 pages, 6 figure
A short note on a mutation of Cheema-sahebi (Syn. Selection-7)
Kurze Mitteilung iiber eine Mutante von Cheema-sahebi (Syn. Selection-7)Die Trauben- und Beerenmerkmale einer spontan entstandenen Knospenmutante der Tafeltraubensorte Cheema-sahebi werden beschrieben. Die Beeren der Mutante sind gegenüber der Ausgangsform auffällig verlängert. Während diese bei Verpackung und Transport 8-100/o ihrer Beeren verliert, zeichnet sich die Mutante durch eine hohe Haftfestigkeit ihrer Beeren aus
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Full 3D numerical analysis of a twin screw compressor by employing open-source software
The push for having more reliable and efficient positive displacement machines (both compressors and expanders) for vapor compression and power generation (e.g., ORCs) applications has moved researchers to an always more spread employment of computational fluid dynamics (CFD). In particular, twin screw compressors, because of their high efficiency compared to other compressor types, have received interest over the last years. The numerical analysis of such machines is challenging: the deforming working chambers are very difficult to be correctly replicated. The relative motion of the rotors and the variation of the gaps during machine operation are few of the major difficulties in implementing reliable CFD models. A custom mesh generation algorithm is therefore often required for sumulating the machine operation.
In this work, SCORG-V5.2.2 was used to generate the meshes of the deforming domain around rotating parts of the machines. The open-source software OpenFOAM-v1606+ is then employed to compute the flow field associated with the operation of the twin screw. The coupling of the two tools has been carried out in this work, applying the methodology to a twin screw machine
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Numerical investigation of flow characteristics in twin-screw pump under cavitating conditions
In order to investigate the flow characteristics and the formation process of cavitation in twin-screw pumps, three-dimensional CFD (Computational Fluid Dynamics) numerical analysis has been carried out. A conformal structured moving mesh generated by an in-house code SCORG was applied for the rotor domain. The VOF (Volume of Fluid) Method has been adopted for dealing with the liquid-gas two-phase flow, while the bubble dynamics was handled by a homogenous cavitation model. By changing the rotation speed and discharge pressure, the intensity, distribution area and variation of cavitation at different rotor angle were obtained. The effects of rotation speed and discharge pressure on cavitation characteristics have been analysed. Calculation results with cavitation model are compared with the results without cavitation and the experimentally obtained values. The influence of cavitation on the performance of a screw pump in terms of the mass flow rate, pressure distribution, rotor torque and the shaft power have been analysed and discussed
Clinical competence in performing and recognising a mediolateral episiotomy of protective angle and length: a systematic review
Objective: It is assumed that all doctors and midwives understand and apply evidence‐based principles in performing episiotomies in their everyday practice. However, remarkable discrepancies between even the most reputable literature sources in defining and describing the technique of performing mediolateral episiotomy (MLE) suggest that there is much ambiguity and confusion for both researchers and clinicians alike.
Design: The systematic review protocol was written prior to starting the review and registered in the international prospective register of systematic reviews (PROSPERO/ID CRD42017070523) last updated on December 15, 2017. The review is reported using the Preferred Reporting Items for Systematic Reviews and Meta‐Analysis (PRISMA) guidelines.
Methods: A database search was performed using: Medline, CINAHL, Scopus, Informit, the Cochrane Library and PubMed from database inception to 17 September 2017, with a final search on 10 February 2017. Studies were included if they examined clinicians' competency in performing an 'ideal' or 'correct' mediolateral episiotomy, as well as those studies that compared the performance of different professional roles. Studies usually defined an 'ideal' incision as one that met the criteria of an acceptable angle of incision from the midline, starting incision point distance from the midline and in terms of the length of the incision created.
Results: While many of the studies included in this review were not of high quality (author self‐assessment) and had their own study criteria for a MLE, the literature suggests clinicians are generally unable to perform or simulate episiotomies within such standards. Overall, most of the literature reported doctors were performing more 'ideal', lateral and longer incisions compared to midwives; however, there were studies that found the opposite, showing statistically significant results in favour of midwives performing more protective episiotomies. There was no association between clinicians' participation in formal training courses and their ability to perform the 'ideal' incision, though one study did find an increased number of episiotomies performed under supervision improved clinicians competency.
Conclusion: The obvious lack of understanding around defining and performing MLE for clinicians of various professional roles suggests the need to produce a uniform set of guidelines, and to develop a universal, low‐cost approach for teaching and performing the MLE technique in any clinical environment around the world
Evaluation of the Liquisolid Compacts Using Response Surface Methodology
Liquisolid Compacts technique has potential to develop sustained release formulations. It involves conversion of liquid drug (either solution or suspension) in non-volatile solvent into free-flowing, non adherent, dry looking and readily compressible powder. In the present work, an attempt was made to develop such formulation of Diltiazem HCl and evaluation using Response surface methodology. Liquisolid compacts were prepared by dissolving Diltiazem HCl in Polyethylene Glycol 400. Then a binary mixture of carrier-coating material, Avicel and Aerosil, was added to liquid medication under continuous mixing in mortar. The HPMC K4M was used as adjuvant for sustaining the drug release. The pre-compression studies for all the formulations were also carried out. The Liquisolid compacts were evaluated in-vitro dissolution studies. The experimental data was evaluated using Design Expert Software. The % Drug Concentration, ratio of Carrier to Coating material and amount of HPMC K4M are taken as three factors. Response Surface methodology was used to study the influence of the each factor on the response. The present investigation showed that Polyethylene Glycol 400 has important role in release retardation of drug in Liquisolid compacts. The reduction in Tg can be reason for same. The Response surface methodology showed that all the factors were significantly affect the release at 16 hrs.
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