Measuring the spin up of the Accreting Millisecond Pulsar XTE J1751-305

We perform a timing analysis on RXTE data of the accreting millisecond pulsar XTE J1751-305 observed during the April 2002 outburst. After having corrected for Doppler effects on the pulse phases due to the orbital motion of the source, we performed a timing analysis on the phase delays, which gives, for the first time for this source, an estimate of the average spin frequency derivative = (3.7 +/- 1.0)E-13 Hz/s. We discuss the torque resulting from the spin-up of the neutron star deriving a dynamical estimate of the mass accretion rate and comparing it with the one obtained from X-ray flux. Constraints on the distance to the source are discussed, leading to a lower limit of \sim 6.7 kpc.Comment: 7 pages, 3 figures, Accepted for publication by MNRA

Age, Gender, and Socioeconomic Status Differences in Explicit and Implicit Beliefs About Effortlessly Perfect Self-Presentation

Feeling pressure to project an image of effortless perfection -- always appearing to perform with self-confidence and ease --- has been portrayed in the media as an increasingly common mental health vulnerability with potentially serious implications for college women. Despite this, almost no empirical research exists on effortlessly perfect self–presentation (EPSP) or demographic differences in it. • Some recent research suggests that perfectionism is on the rise among young people (Curran & Hill, 2017), and that it is more associated with mental health problems among students with high rather than low socioeconomic status (Lyman & Luthar, 2014). However, these studies did not focus specifically on EPSP, which differs from more typical perfectionism in that it prohibits apparent effort or anxiety while striving for perfection. Of the two published studies on EPSP, one did not examine demographic differences (Flett et al., 2016) and the other found higher endorsement of EPSP among men than among women (Travers et al., 2016). • Anonymous interviews we conducted about EPSP in 40 college students (Glazer et al., in prep) yielded very complex, self-contradictory responses suggesting that beliefs about EPSP may be characterized by stigma and ambivalence. For this reason we decided to focus the current study on indirect and implicit measures of EPSP. • In this study, participants completed three new scales about EPSP, along with the two existing measures of this phenomenon, several mental health measures, and demographics questions. They also rated the perceived social status and self-esteem of two target individuals in a within-person experimental design

Timing of the Accreting Millisecond Pulsar XTE J1814-338

We present a precise timing analysis of the accreting millisecond pulsar XTE J1814-338 during its 2003 outburst, observed by RXTE. A full orbital solution is given for the first time; Doppler effects induced by the motion of the source in the binary system were corrected, leading to a refined estimate of the orbital period, P_orb=15388.7229(2)s, and of the projected semimajor axis, a sini/c= 390.633(9) lt-ms. We could then investigate the spin behaviour of the accreting compact object during the outburst. We report here a refined value of the spin frequency (nu=314.35610879(1) Hz) and the first estimate of the spin frequency derivative of this source while accreting (nu^dot=(-6.7 +/- 0.7) 10^(-14) Hz/s). This spin down behaviour arises when both the fundamental frequency and the second harmonic are taken into consideration. We discuss this in the context of the interaction between the disc and the quickly rotating magnetosphere, at accretion rates sufficiently low to allow a threading of the accretion disc in regions where the Keplerian velocity is slower than the magnetosphere velocity. We also present indications of a jitter of the pulse phases around the mean trend, which we argue results from movements of the accreting hotspots in response to variations of the accretion rate.Comment: 7 pages, 4 figures, Accepted for publication by MNRA

Timing of the accreting millisecond pulsar IGR~J17511--3057

{Timing analysis of Accretion-powered Millisecond Pulsars (AMPs) is a powerful tool to probe the physics of compact objects. The recently discovered \newigrj is the 12 discovered out of the 13 AMPs known. The Rossi XTE satellite provided an extensive coverage of the 25 days-long observation of the source outburst.} {Our goal is to investigate the complex interaction between the neutron star magnetic field and the accretion disk, determining the angular momentum exchange between them. The presence of a millisecond coherent flux modulation allows us to investigate such interaction from the study of pulse arrival times. In order to separate the neutron star proper spin frequency variations from other effects, a precise set of orbital ephemeris is mandatory.} {Using timing techniques, we analysed the pulse phase delays fitting differential corrections to the orbital parameters. To remove the effects of pulse phase fluctuations we applied the timing technique already successfully applied to the case of an another AMP, XTE J1807-294.} {We report a precise set of orbital ephemeris. We demonstrate that the companion star is a main sequence star. We find pulse phase delays fluctuations on the first harmonic with a characteristic amplitude of about 0.05, similar to what also observed in the case of the AMP XTE J1814-338. For the second time an AMP shows a third harmonic detected during the entire outburst. The first harmonic phase delays show a puzzling behaviour, while the second harmonic phase delays show a clear spin-up. Also the third harmonic shows a spin-up, although not highly significant (3$\sigma$ c.l.). The presence of a fourth harmonic is also reported. In the hypothesis that the second harmonic is a good tracer of the spin frequency of the neutron star, we find a mean spin frequency derivative for this source of \np{1.65(18)}{-13} Hz s$^{-1}$.} (continue ...)Comment: 9 pages, 12 figures, A&A accepted on 23/10/201

Rebelliousness, Effortful Control, and Risky Behavior: Metamotivational and Temperamental Predictors of Risk-Taking in Older Adolescents

Adolescence is frequently regarded as a time of increased vulnerability to engaging in risky behaviors such as binge drinking, unsafe sexual activities, and illicit drug use. The present study examined risk perception and risk-taking behavior in older adolescents from two different perspectives, by examining temperamental and metamotivational predictors of likelihood of engaging in risky activities. A sample of 76 undergraduate students aged 17 to 19 years completed a questionnaire package that included the Motivational Style Profile, Rebelliousness Questionnaire, the short form of the Adult Temperament Questionnaire, and the expected risk and expected involvement subscales of the Cognitive Appraisal of Risky Events. Findings indicated that rebelliousness and effortful control (i.e., ability to appropriately regulate attention and behavior) were strong predictors of expected involvement in risky behaviors, and that proactive rebelliousness was a particularly influential predictor of illicit drug use, risky sexual activities, aggressive and illegal behaviors, and risky academic and work behaviors. In addition, a number of significant correlations between temperamental variables and metamotivational dominance were observed, lending empirical support to reversal theory’s metamotivational constructs and their measurement

Phylogenetic analysis of nodulation and nitrogen fixation genes of a brazilian collection of Bradyrhizobium strains.

The genus Bradyrhizobium encompasses a variety of bacteria that can live in symbiotic and endophytic associations with legumes and non-legumes, and are characterized by physiological and symbiotic versatility and broad geographical distribution. In studies with Bradyrhizobium strains the comparison of phylogenies of nodulation and housekeeping genes has indicated a monophyletic origin of nodulation genes and diffusion by vertical and horizontal gene transfer, the last one probably influenced by the host plants. In previous studies with the strains analyzed in this study we have shown high diversity in the 16S rRNA, ITS rRNA, atpD, glnII, dnaK and recA housekeeping genes (Menna et al., 2006, 2009). However, despite indications of great genetic variability within the Bradyrhizobium genus, little is known about the phylogeny of the nodulation and nitrogen fixation genes. In this study the nodulation genes nodY/K, nodA and nodZ and the nitrogen fixation gene nifH of forty Bradyrhizobium strains were sequenced and analyzed. The great majority of the strains are from tropical regions and were isolated from members of the three subfamilies and nine tribes of the family Leguminosae (=Fabaceae). In all phylogenetic trees a high level of genetic diversity was observed and several clusters were correlated with the subfamilies of the host plants. One example was with the symbionts of Glycine max and Acacia sp., classified in the subfamilies Papilionoideae and Mimosoideae, respectively. In the phylogenetic trees built with nodY/K and nodA the symbionts of Acacia sp. were clustered in an isolated group, and no amplification was obtained for the nodZ gene. A successful amplification of nifH gene was obtained with all strains, and the resulting phylogenetic tree had similar clusters in comparison to the trees build with the nodulation genes (nodY/K, nodA and nodZ). The strains which failed in the amplification for some nodulation genes occupied an isolated position in the nifH tree. The comparison of all trees has shown no correlation between housekeeping and nod and nifH genes. The results pointed out the high diversity of nodulation and nitrogen fixation genes of tropical Bradyrhizobium strains and in several clusters high correlation between nod and nif genes and the host plants was observed. Partially financed by: CNPq (577933/2008-6; 558455/2008-5; 470162/2009-0

Effects of chronic estradiol treatment on the thyroid gland structure and function of ovariectomized rats

<p>Abstract</p> <p>Background</p> <p>Estrogen therapy is widely used nowadays in women to treat many postmenopausal symptoms but it may have some undesirable effects due to multiple organs affection. So, the aim of this study was to determine the effects of chronic estradiol treatment on the structure and function of the thyroid gland in ovarictomized rats as a model simulating menopause.</p> <p>Findings</p> <p>Thirty adult female Wistar rats divided into three groups were used in this study; the first group was sham-operated, while the second and third groups were ovariectomized. The first and second groups were injected with olive oil while the third group was injected with estradiol dipropionate daily for three months, after that; hormonal assay for T3, T4, TSH and specimens of the thyroid were taken and processed to be examined by light and electron microscopy. The results of this study revealed that serum levels of T3 and T4 decreased in ovariectomized animals and significantly increased after estradiol treatment, while TSH increased in ovariectomized animals and decreased with estradiol treatment. Histological and morphometric study in ovariectomized group revealed marked accumulation of colloid in follicular lumens with decreased epithelial height in addition to increased connective tissue amount. After estradiol treatment the follicles became smaller in size, having small amount of colloid with increased epithelial height in addition to decreased connective tissue content. Ultrastructural study supported these results in addition to the presence of large amount of intracytoplasmic colloid vesicles after estradiol treatment.</p> <p>Conclusion</p> <p>Low estrogen level may lead to mild thyroidal hypofunction while estradiol treatment may lead to hyperactivity so it should be used very cautiously in the treatment of postmenopausal symptoms to avoid its undesirable stimulatory effect on the thyroid.</p

Coupling Between Periodic and Aperiodic Variability in SAX J1808.4-3658

We detect a significant broadening in the wings of the 401 Hz peak in the power spectrum of the accreting millisecond binary pulsar SAX J1808.4-3658. This feature is consistent with the convolution of the red noise present in the power spectrum with the harmonic line. We conclude that the flux modulated by the spin period shows aperiodic variability similar to the red noise in the overall flux, suggesting such variability also originates at the magnetic caps close to the neutron star surface. This is analogous to the results found in some longer period, higher magnetic field pulsators in high mass X-ray binaries.Comment: 16 pages, 3 figures, to be published in The Astrophysical Journa

Order in the Chaos: Spin-up and Spin-down during the 2002 Outburst of SAX J1808.4–3658

We present a timing analysis of the 2002 outburst of the accreting millisecond pulsar SAX J1808.4-3658. A study of the phase delays of the entire pulse profile shows a behavior that is surprising and difficult to interpret: superposed to a general trend, a big jump by about 0.2 in phase is visible, starting at day 14 after the beginning of the outburst. An analysis of the pulse profile indicates the presence of a significant first harmonic. Studying the fundamental and the first harmonic separately, we find that the phase delays of the first harmonic are more regular, with no sign of the jump observed in the fundamental. The fitting of the phase delays of the first harmonic with a model which takes into account the observed exponential decay of the X-ray flux (and therefore of the mass accretion rate onto the neutron star) gives important information on the torque acting on the neutron star during the outburst. We find that the source shows spin-up in the first part of the outburst, while a spin-down dominates at the end. From these results we derive an estimate of the neutron star magnetic field strength