154 research outputs found

    A spectroscopic analysis of the chemically peculiar star HD207561

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    In this paper we present a high-resolution spectroscopic analysis of the chemically peculiar star HD207561. During a survey programme to search for new roAp stars in the Northern hemisphere, Joshi et al. (2006) observed significant photometric variability on two consecutive nights in the year 2000. The amplitude spectra of the light curves obtained on these two nights showed oscillations with a frequency of 2.79 mHz [P~6-min]. However, subsequent follow-up observations could not confirm any rapid variability. In order to determine the spectroscopic nature of HD207561, high-resolution spectroscopic and spectro-polarimetric observations were carried out. A reasonable fit of the calculated Hbeta line profile to the observed one yields the effective temperature (Teff) and surface gravity (log g) as 7300 K and 3.7 dex, respectively. The derived projected rotational velocity (vsin i) for HD207561 is 74 km/sec indicative of a relatively fast rotator. The position of HD207561 in the H-R diagram implies that this is slightly evolved from the main-sequence and located well within the delta-Scuti instability strip. The abundance analysis indicates the star has slight under-abundances of Ca and Sc and mild over-abundances of iron-peak elements. The spectro-polarimetric study of HD207561 shows that the effective magnetic field is within the observational error of 100 gauss (G). The spectroscopic analysis revealed that the star has most of the characteristics similar to an Am star, rather than an Ap star, and that it lies in the delta-Scuti instability strip; hence roAp pulsations are not expected in HD207561, but low-overtone modes might be excited.Comment: 8 pages, 7 figures, 3 tables. Accepted for pubblication in MNRA

    Enhanced recovery after surgery: current status and future progress

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    Enhanced Recovery After Surgery (ERAS) pathways were first introduced almost a quarter of a century ago and represent a paradigm shift in perioperative care that reduced postoperative complications and hospital length of stay, improved postoperative quality of life and reduced overall healthcare costs. Gradual recognition of the generalizability of the interventions and transferable improvements in postoperative outcomes, led them to becoming standard of care for several surgical procedures. In this article we critically review the current status of ERAS pathways, address related controversies, and propose measures for future progress

    Pain management after elective craniotomy: A systematic review with procedure-specific postoperative pain management (PROSPECT) recommendations.

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    BACKGROUND Pain after craniotomy can be intense and its management is often suboptimal. OBJECTIVES We aimed to evaluate the available literature and develop recommendations for optimal pain management after craniotomy. DESIGN A systematic review using procedure-specific postoperative pain management (PROSPECT) methodology was undertaken. DATA SOURCES Randomised controlled trials and systematic reviews published in English from 1 January 2010 to 30 June 2021 assessing pain after craniotomy using analgesic, anaesthetic or surgical interventions were identified from MEDLINE, Embase and Cochrane Databases. ELIGIBILITY CRITERIA Each randomised controlled trial (RCT) and systematic review was critically evaluated and included only if met the PROSPECT requirements. Included studies were evaluated for clinically relevant differences in pain scores, use of nonopioid analgesics, such as paracetamol and NSAIDs, and current clinical relevance. RESULTS Out of 126 eligible studies identified, 53 RCTs and seven systematic review or meta-analyses met the inclusion criteria. Pre-operative and intra-operative interventions that improved postoperative pain were paracetamol, NSAIDs, intravenous dexmedetomidine infusion, regional analgesia techniques, including incision-site infiltration, scalp nerve block and acupuncture. Limited evidence was found for flupirtine, intra-operative magnesium sulphate infusion, intra-operative lidocaine infusion, infiltration adjuvants (hyaluronidase, dexamethasone and α-adrenergic agonist added to local anaesthetic solution). No evidence was found for metamizole, postoperative subcutaneous sumatriptan, pre-operative oral vitamin D, bilateral maxillary block or superficial cervical plexus block. CONCLUSIONS The analgesic regimen for craniotomy should include paracetamol, NSAIDs, intravenous dexmedetomidine infusion and a regional analgesic technique (either incision-site infiltration or scalp nerve block), with opioids as rescue analgesics. Further RCTs are required to confirm the influence of the recommended analgesic regimen on postoperative pain relief

    PROSPECT guideline for total hip arthroplasty: a systematic review and procedure-specific postoperative pain management recommendations

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    The aim of this systematic review was to develop recommendations for the management of postoperative pain after primary elective total hip arthroplasty, updating the previous procedure-specific postoperative pain management (PROSPECT) guidelines published in 2005 and updated in July 2010. Randomised controlled trials and meta-analyses published between July 2010 and December 2019 assessing postoperative pain using analgesic, anaesthetic, surgical or other interventions were identified from MEDLINE, Embase and Cochrane databases. Five hundred and twenty studies were initially identified, of which 108 randomised trials and 21 meta-analyses met the inclusion criteria. Peri-operative interventions that improved postoperative pain include: paracetamol; cyclo-oxygenase-2-selective inhibitors; non-steroidal anti-inflammatory drugs; and intravenous dexamethasone. In addition, peripheral nerve blocks (femoral nerve block; lumbar plexus block; fascia iliaca block), single-shot local infiltration analgesia, intrathecal morphine and epidural analgesia also improved pain. Limited or inconsistent evidence was found for all other approaches evaluated. Surgical and anaesthetic techniques appear to have a minor impact on postoperative pain, and thus their choice should be based on criteria other than pain. In summary, the analgesic regimen for total hip arthroplasty should include pre-operative or intra-operative paracetamol and cyclo-oxygenase-2-selective inhibitors or non-steroidal anti-inflammatory drugs, continued postoperatively with opioids used as rescue analgesics. In addition, intra-operative intravenous dexamethasone 8-10 mg is recommended. Regional analgesic techniques such as fascia iliaca block or local infiltration analgesia are recommended, especially if there are contra-indications to basic analgesics and/or in patients with high expected postoperative pain. Epidural analgesia, femoral nerve block, lumbar plexus block and gabapentinoid administration are not recommended as the adverse effects outweigh the benefits. Although intrathecal morphine 0.1 mg can be used, the PROSPECT group emphasises the risks and side-effects associated with its use and provides evidence that adequate analgesia may be achieved with basic analgesics and regional techniques without intrathecal morphine

    The Nainital-Cape Survey -- II:Report for pulsation in five chemically peculiar A-type stars and presentation of 140 null results

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    To search photometric variability in chemically peculiar A type stars in the northern hemisphere. High-speed photometric observations of Ap and Am star candidates have been carried out from ARIES (Manora Peak, Nainital) using a three-channel fast photometer attached to the ARIES 104-cm Sampurnanand telescope. This paper presents three new variables: HD 113878, HD 118660 and HD 207561. During the time span of the survey (1999 December to 2004 January) pulsations of the δ\delta Sct type were also found for the two evolved Am stars HD 102480 and HD 98851, as reported in Joshi et al. (2002, 2003). Additionally, we present 140 null results of the survey for this time span. The star HD 113878 pulsates with a period of 2.31 hr, which is typical of δ\delta Sct stars. HD 118660 exhibits multi-periodic variability with a prominent period of nearly 1 hr. These periods need to be investigated and make HD 118660 a particularly interesting target for further observations. For HD 207561, a star classified as Am, a probable pulsation with a period of 6 min was found in the light curves obtained on two consecutive nights. Both HD 102480 and HD 98851 exhibit unusual alternating high and low amplitude maxima, with a period ratio of 2:1. The analysis of the null results confirms the photometric quality of the NainitalComment: 14 pages, 13 figures, Accepted for publication in A&

    Discovery of unusual pulsations in the cool, evolved Am stars HD 98851 and HD 102480

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    The chemically peculiar (CP) stars HD 98851 and HD 102480 have been discovered to be unusual pulsators during the ``Naini Tal Cape Survey'' programme to search for pulsational variability in CP stars. Time series photometric and spectroscopic observations of these newly discovered stars are reported here. Fourier analyses of the time series photometry reveal that HD 98851 is pulsating mainly with frequencies 0.208 mHz and 0.103 mHz, and HD 102480 is pulsating with frequencies 0.107 mHz, 0.156 mHz and 0.198 mHz. The frequency identifications are all subject to 1 d1^{-1} cycle count ambiguities. We have matched the observed low resolution spectra of HD 98851 and HD 102480 in the range 3500-7400 \AA with theoretical synthetic spectra using Kurucz models with solar metallicity and a micro-turbulent velocity 2 km s1^{-1}. These yield Teff=7000±250T_{eff}=7000\pm250 K, log g=3.5±0.5g=3.5 \pm 0.5 for HD 98851 and Teff=6750±250T_{eff} = 6750 \pm 250 K, log g=3.0±0.5g = 3.0 \pm 0.5 for HD 102480. We determined the equivalent H-line spectral class of these stars to be F1 IV and F3 III/IV, respectively. A comparison of the location of HD 98851 and HD 102480 in the HR diagram with theoretical stellar evolutionary tracks indicates that both stars are about 1-Gyr-old, 2-MM_{\odot} stars that lie towards the red edge of the δ\delta Sct instability strip. We conclude that HD 98851 and HD 102480 are cool, evolved Am pulsators. The light curves of these pulsating stars have alternating high and low amplitudes, nearly harmonic (or sub-harmonic) period ratios, high pulsational overtones and Am spectral types. This is unusual for both Am and δ\delta Sct pulsators, making these stars interesting objects.Comment: 9 pages, 6 Figures, Accepted for publication in MNRA

    HD 12098 -A new northern hemisphere roAp star

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    We present the analysis of 65 hours of high speed photometric observations of HD 12098 taken from State Observatory, Naini Tal and Gurushikhar Observatory, Mt. Abu on sixteen nights spanning from November 1999 to November 2000. HD 12098 is the first rapidly oscillating Ap star discovered from the "Naini Tal-Cape survey for northern hemisphere roAp stars". It is the 32nd in the complete list. HD 12098 exhibits one predominant mode of oscillation a

    The Naini Tal -Cape survey for pulsations in chemically peculiarA-type stars: I. Methods and preliminary results

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    A new survey for pulsating, chemically peculiar A- and F-type stars in the northern hemisphere has been initiated using the 1-m telescope at Uttar Pradesh State Observatory in Naini Tal. The survey is primarily structured to reveal high-overtone pulsations in chemically peculiar A-F stars, but it is also revealing low-overton

    HD 12098, the new far-Northern roAp star

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    The rapidly oscillating Ap (roAp) stars are cool, magnetic, chemically peculiar stars which pulsate in non-radial p-modes in the period range 4-16 min and have Johnson B amplitudes less than 8 mmag. "The NainiTal-Cape survey" to search for and study new roAp stars in the northern hemisphere was initiated in 1998 in collaboration between ISAC & UPSO from India and SAAO & UCT from South Africa. HD12098 is the first roAp star discovered in this survey and also the first far northern hemisphere roAp star. During the initial observations the star showed modulation in the pulsation amplitude indicating the multi-periodicity of pulsations. The multi-periodicity may be either due to the excitation of different modes or due to the rotation of the star. In order to resolve these frequencies HD12098 was observed extensively in October 2000. The preliminary results of these observations are presented here
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