1,228 research outputs found

    The reproduction biology of Abudefduf sexfasciatus in the Persian Gulf (Larak Island)

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    The reproduction biology of A. sexfasciatus, one of the main and important ornamental fishes in the Persian Gulf were studied during 1997-98. For sampling, Larak island sited on south-eastern of Bandar-Abbas was chosen. The main fishing gear was hook for collecting samples. During this investigation, weight, length (FL & T.L), GSI, HSI, Kf, sex ratio, LM50 and sexual overlap zone were measured or calculated. Also, the histological studies were done on gonads. The results showed that this species is a protogenous hermaphrodite. A. sexfasciatus has an allometric growth and the results of GSI, HSI and Kf indicated that the spawning season occured in spring as a total spawner species. The sex ratio was found M:F=1.00:1.24 without any significant difference. The overlap zone was recongnized 30mm (with a range of 125-155mm). The LM50 was calculated 130-140mm for females and 160-170mm for males. The size at first maturity for females and males were determined 105 and 120mm, respectively

    Human agt-p.Met268thr and coronary heart disease risk: A case-control study and meta-analysis

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    Summary Background. Polymorphisms in genes, which is involved in the renin–angiotensin system, play an important role in the pathogenesis of coronary heart disease (CHD). Polymorphism of c.803T>C in the human angiotensinogen gene results in methionine (M) to threonine (T) substitution at codon 268 (p.Met268Thr), which traditionally has been known as M235T. This polymorphism may contribute to cardiovascular diseases. Objectives. The aim of this study was to investigate the association between p.Met268Thr polymorphism in the angiotensinogen gene and coronary heart disease (CHD) through a case-control study, which is followed by a meta-analysis. Material and methods. In the case-control study, c.803T>C genotyping of 217 subjects (102 CHD cases vs 115 controls) was investigated by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. In the meta-analysis, 31 studies were included, reflecting 12,028 people with CHD and 16,362 healthy controls. Results. The data from the case-control study revealed that MT (OR, 1.875; 95%CI, 1.060–3.316; p = 0.031) and TT (OR, 3.389; 95%CI, 1.251–9.179; p = 0.016) genotypes are significantly associated with CHD. The meta-analysis revealed a significant association in the recessive model (OR, 1.156; 95%CI, 1.011–1.321; p = 0.034). Conclusions. Although the pooled OR of the meta-analysis showed that there is an increased risk of CHD conferred by p.Met268Thr of the AGT gene, this association was weak, which could be attributed to a bias in publications. © Copyright by Wydawnictwo Continuo

    Optical and near infrared observations of SN 2014ck: an outlier among the Type Iax supernovae

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    We present a comprehensive set of optical and near-infrared photometric and spectroscopic observations for SN 2014ck, extending from pre-maximum to six months later. These data indicate that SN 2014ck is photometrically nearly identical to SN 2002cx, which is the prototype of the class of peculiar transients named SNe Iax. Similar to SN 2002cx, SN 2014ck reached a peak brightness MB=−17.37±0.15M_B=-17.37 \pm 0.15 mag, with a post-maximum decline-rate Δm15(B)=1.76±0.15\Delta m_{15} (B) = 1.76 \pm 0.15 mag. However, the spectroscopic sequence shows similarities with SN 2008ha, which was three magnitudes fainter and faster declining. In particular, SN 2014ck exhibits extremely low ejecta velocities, ∼3000\sim 3000 km s−1^{-1} at maximum, which are close to the value measured for SN 2008ha and half the value inferred for SN 2002cx. The bolometric light curve of SN 2014ck is consistent with the production of 0.10−0.03+0.04M⊙0.10^{+0.04}_{-0.03} M_{\odot} of 56^{56}Ni. The spectral identification of several iron-peak features, in particular Co II lines in the NIR, provides a clear link to SNe Ia. Also, the detection of narrow Si, S and C features in the pre-maximum spectra suggests a thermonuclear explosion mechanism. The late-phase spectra show a complex overlap of both permitted and forbidden Fe, Ca and Co lines. The appearance of strong [Ca~II] λλ\lambda\lambda7292, 7324 again mirrors the late-time spectra of SN 2008ha and SN 2002cx. The photometric resemblance to SN 2002cx and the spectral similarities to SN 2008ha highlight the peculiarity of SN 2014ck, and the complexity and heterogeneity of the SNe Iax class.Comment: MNRAS Accepted 2016 March 22. Received 2016 March

    The Broad Absorption Line Tidal Disruption Event iPTF15af: Optical and Ultraviolet Evolution

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    We present multi-wavelength observations of the tidal disruption event (TDE) iPTF15af, discovered by the intermediate Palomar Transient Factory (iPTF) survey at redshift z=0.07897z=0.07897. The optical and ultraviolet (UV) light curves of the transient show a slow decay over five months, in agreement with previous optically discovered TDEs. It also has a comparable black-body peak luminosity of Lpeak≈1.5×1044L_{\rm{peak}} \approx 1.5 \times 10^{44} erg/s. The inferred temperature from the optical and UV data shows a value of (3−-5) ×104\times 10^4 K. The transient is not detected in X-rays up to LX<3×1042L_X < 3 \times 10^{42}erg/s within the first five months after discovery. The optical spectra exhibit two distinct broad emission lines in the He II region, and at later times also Hα\alpha emission. Additionally, emission from [N III] and [O III] is detected, likely produced by the Bowen fluorescence effect. UV spectra reveal broad emission and absorption lines associated with high-ionization states of N V, C IV, Si IV, and possibly P V. These features, analogous to those of broad absorption line quasars (BAL QSOs), require an absorber with column densities NH>1023N_{\rm{H}} > 10^{23} cm−2^{-2}. This optically thick gas would also explain the non-detection in soft X-rays. The profile of the absorption lines with the highest column density material at the largest velocity is opposite that of BAL QSOs. We suggest that radiation pressure generated by the TDE flare at early times could have provided the initial acceleration mechanism for this gas. Spectral UV line monitoring of future TDEs could test this proposal.Comment: 20 pages, 12 figures, published in Ap

    The multi-faceted Type II-L supernova 2014G from pre-maximum to nebular phase

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    We present multi-band ultraviolet, optical, and near-infrared photometry, along with visual-wavelength spectroscopy, of supernova (SN) 2014G in the nearby galaxy NGC 3448 (25 Mpc). The early-phase spectra show strong emission lines of the high ionisation species He II/N IV/C IV during the first 2-3 d after explosion, traces of a metal-rich CSM probably due to pre-explosion mass loss events. These disappear by day 9 and the spectral evolution then continues matching that of normal Type II SNe. The post-maximum light curve declines at a rate typical of Type II-L class. The extensive photometric coverage tracks the drop from the photospheric stage and constrains the radioactive tail, with a steeper decline rate than that expected from the 56^{56}Co decay if γ\gamma-rays are fully trapped by the ejecta. We report the appearance of an unusual feature on the blue-side of Hα\alpha after 100 d, which evolves to appear as a flat spectral feature linking Hα\alpha and the O I doublet. This may be due to interaction of the ejecta with a strongly asymmetric, and possibly bipolar CSM. Finally, we report two deep spectra at ~190 and 340 d after explosion, the latter being arguably one of the latest spectra for a Type II-L SN. By modelling the spectral region around the Ca II, we find a supersolar Ni/Fe production. The strength of the O I λλ\lambda\lambda6300,6363 doublet, compared with synthetic nebular spectra, suggests a progenitor with a zero-age main-sequence mass between 15 and 19 M⊙_\odot.Comment: 24 pages, 14 figure

    Delayed Decision-making in Real-time Beatbox Percussion Classification

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    This is an electronic version of an article published in Journal of New Music Research, 39(3), 203-213, 2010. doi:10.1080/09298215.2010.512979. Journal of New Music Research is available online at: www.tandfonline.com/openurl?genre=article&issn=1744-5027&volume=39&issue=3&spage=20

    AT 2017be - a new member of the class of Intermediate-Luminosity Red Transients

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    We report the results of our spectrophotometric monitoring campaign for AT~2017be in NGC~2537. Its lightcurve reveals a fast rise to an optical maximum, followed by a plateau lasting about 30 days, and finally a fast decline. Its absolute peak magnitude (MrM_{r} ≃\simeq −-12 mag\rm{mag}) is fainter than that of core-collapse supernovae, and is consistent with those of supernova impostors and other Intermediate-Luminosity Optical Transients. The quasi-bolometric lightcurve peaks at ∼\sim 2 ×\times 1040^{40} erg s−1^{-1}, and the late-time photometry allows us to constrain an ejected 56^{56}Ni mass of ∼\sim 8 ×\times 10−4^{-4}\msun. The spectra of AT~2017be show minor evolution over the observational period, a relatively blue continuum showing at early phases, which becomes redder with time. A prominent Hα\alpha emission line always dominates over other Balmer lines. Weak Fe {\sc ii} features, Ca~{\sc ii} H&\&K and the Ca {\sc ii} NIR triplet are also visible, while P-Cygni absorption troughs are found in a high resolution spectrum. In addition, the [Ca~{\sc ii}] λ\lambda7291,7324 doublet is visible in all spectra. This feature is typical of Intermediate-Luminosity Red Transients (ILRTs), similar to SN~2008S. The relatively shallow archival Spitzer data are not particularly constraining. On the other hand, a non-detection in deeper near-infrared HST images disfavours a massive Luminous Blue Variable eruption as the origin for AT~2017be. As has been suggested for other ILRTs, we propose that AT~2017be is a candidate for a weak electron-capture supernova explosion of a super-asymptotic giant branch star, still embedded in a thick dusty envelope.Comment: 21 pages, 15 figures, accepted by MNRA
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