A remarkable recurrent nova in M 31: The predicted 2014 outburst in X-rays with Swift

The M 31 nova M31N 2008-12a was recently found to be a recurrent nova (RN) with a recurrence time of about 1 year. This is by far the fastest recurrence time scale of any known RNe. Our optical monitoring programme detected the predicted 2014 outburst of M31N 2008-12a in early October. We immediately initiated an X-ray/UV monitoring campaign with Swift to study the multiwavelength evolution of the outburst. We monitored M31N 2008-12a with daily Swift observations for 20 days after discovery, covering the entire supersoft X-ray source (SSS) phase. We detected SSS emission around day six after outburst. The SSS state lasted for approximately two weeks until about day 19. M31N 2008-12a was a bright X-ray source with a high blackbody temperature. The X-ray properties of this outburst were very similar to the 2013 eruption. Combined X-ray spectra show a fast rise and decline of the effective blackbody temperature. The short-term X-ray light curve showed strong, aperiodic variability which decreased significantly after about day 14. Overall, the X-ray properties of M31N 2008-12a are consistent with the average population properties of M 31 novae. The optical and X-ray light curves can be scaled uniformly to show similar time scales as those of the Galactic RNe U Sco or RS Oph. The SSS evolution time scales and effective temperatures are consistent with a high-mass WD. We predict the next outburst of M31N 2008-12a to occur in autumn 2015.Comment: 13 pages, 7 figures, 3 tables; accepted for publication in A&

Anharmonic magnetic deformation of self-assembled molecular nanocapsules

High magnetic fields were used to deform spherical nanocapsules, self-assembled from bola-amphiphilic sexithiophene molecules. At low fields the deformation -- measured through linear birefringence -- scales quadratically with the capsule radius and with the magnetic field strength. These data confirm a long standing theoretical prediction (W. Helfrich, Phys. Lett. {\bf 43A}, 409 (1973)), and permits the determination of the bending rigidity of the capsules as (2.6$\pm$0.8)$\times 10^{-21}$ J. At high fields, an enhanced rigidity is found which cannot be explained within the Helfrich model. We propose a complete form of the free energy functional that accounts for this behaviour, and allows discussion of the formation and stability of nanocapsules in solution.Comment: 4 pages, 3 figures, accepted in Phys. Rev. Let

Long-term palliation of right-sided congestive heart failure after stenting a recurrent cor triatriatum dexter in a 10½-year-old pug.

A 10½-year-old, male neutered, pug presented with increasing ascites over two months. Echocardiography revealed cor triatriatum dexter with no concurrent cardiovascular anomalies, subsequently confirmed by computed tomography angiography. Balloon dilation of the perforated intra-atrial membrane under fluoroscopic guidance resulted in the transient resolution of all clinical abnormalities, but six months later stenosis and ascites recurred. After repeated balloon dilation, a stent was placed across the membrane. The dog remains asymptomatic fourteen months after the second procedure. One noteworthy feature of this case is the onset of congestive heart failure due to a congenital defect only at more than 10 years of age

A remarkable recurrent nova in M 31: The X-ray observations

Context. Another outburst of the recurrent M 31 nova M31N 2008-12a was announced in late November 2013. Optical data suggest an unprecedentedly short recurrence time of approximately one year. Aims. In this Letter we address the X-ray properties of M31N 2008-12a. Methods. We requested Swift monitoring observations shortly after the optical discovery. We estimated source count rates and extracted X-ray spectra from the resulting data. The corresponding ultraviolet (UV) data was also analysed. Results. M31N 2008-12a was clearly detected as a bright supersoft X-ray source (SSS) only six days after the well-constrained optical discovery. It displayed a short SSS phase of two weeks duration and an exceptionally hot X-ray spectrum with an effective blackbody temperature of ∼ 97 eV. During the SSS phase the X-ray light curve displayed significant variability that might have been accompanied by spectral variations. The very early X-ray variability was found to be anti-correlated with simultaneous variations in the UV flux. Conclusions. The X-ray properties of M31N 2008-12a coherently point towards a high-mass white dwarf in the nova system. This object might be a promising Type Ia supernova progenitor. We re-discovered additional X-ray detections of M31N 2008-12a that are consistent with our data and increase the number of known nova outbursts to seven. This nova is an exceptional object that merits further attention in the future

A remarkable recurrent nova in M 31: The predicted 2014 outburst in X-rays with Swift

The M 31 nova M31N 2008-12a was recently found to be a recurrent nova (RN) with a recurrence time of about 1 year. This is by far the fastest recurrence time scale of any known RNe. Our optical monitoring programme detected the predicted 2014 outburst of M31N 2008-12a in early October. We immediately initiated an X-ray/UV monitoring campaign with Swift to study the multiwavelength evolution of the outburst. We monitored M31N 2008-12a with daily Swift observations for 20 days after discovery, covering the entire supersoft X-ray source (SSS) phase. We detected SSS emission around day six after outburst. The SSS state lasted for approximately two weeks until about day 19. M31N 2008-12a was a bright X-ray source with a high blackbody temperature. The X-ray properties of this outburst were very similar to the 2013 eruption. Combined X-ray spectra show a fast rise and decline of the effective blackbody temperature. The short-term X-ray light curve showed strong, aperiodic variability which decreased significantly after about day 14. Overall, the X-ray properties of M31N 2008-12a are consistent with the average population properties of M 31 novae. The optical and X-ray light curves can be scaled uniformly to show similar time scales as those of the Galactic RNe U Sco or RS Oph. The SSS evolution time scales and effective temperatures are consistent with a high-mass WD. We predict the next outburst of M31N 2008-12a to occur in autumn 2015

Attitudes of Secondary School STEM Teachers towards Supervising Research and Design Activities

Research and design activities are important focus points in international policies for secondary Science, Technology, Engineering and Mathematics (STEM) education. It is up to school teachers to implement and supervise these activities in the STEM classroom. However, not much is known about the attitudes teachers hold towards supervising research projects or design projects. In this study, a questionnaire to measure teacher attitudes towards supervising research activities and design activities in secondary school was completed by 130 Dutch teachers who taught the relatively new Dutch STEM subjects O&O (research and design) and NLT (nature, life, and technology). These integrated STEM subjects are project and context based and are taught in a limited number of schools. Important differences between these integrated STEM subjects are their student and teacher populations: NLT is taught in grades 10–12 by teachers with a qualification in a science subject, while O&O is taught in grades 7–12 and can be given by any teacher in secondary school. The results showed that on average, both O&O and NLT teachers had high self-efficacy scores on supervising research and design projects even when they had received no special education in doing so. Furthermore, the teachers in general viewed supervising research projects as a more relevant activity than supervising design. Since research and design activities are becoming more important in (inter)national curriculum standards, STEM teacher education and subsequent professional development should not only familiarize teachers with supervising research projects, but with design projects as well.Development Psychopathology in context: famil

ethical reasons and political commitment

Political commitments to resist oppression play a central role in the moral lives of many people. Such commitments are also a source of ethical reasons. They influence and organize ethical beliefs, emotions and reasons in an ongoing way. Political commitments to address oppression often contain a concern for the dignity and well-being of others and the objects of political commitments often have value, according to ideal moral theories, such as Kantian and utilitarian theory. However, ideal moral theories do not fully explain the ethical reasons political commitments engender. First, ideal moral theories do not explain the normative priority that agents give to politically committed ethical reasons. Their profound effect on a politically committed agent’s ethical deliberation and choice and the precedence they are given over other ends cannot be wholly understood through the moral obligations within ideal theories. Second, although politically committed reasons are valuable in ideal theory for the benefits they bring to others, they are not fungible with other reasons ideal theory would regard as having equal ethical value. A person might substitute another beneficial humanitarian aim for that to which she is politically committed and nevertheless regard herself as having done a morally wrong thing for failing or betraying her commitment. Politically committed ethical reasons are also motivated and informed by the social location of agents and their relationship to structures of oppression. Although there are universal ethical reasons to oppose oppression, this means that some of a person’s actual ethical reasons will be irreducibly particular

Characterizing model errors in chemical transport modeling of methane: using GOSAT XCH4_{4} data with weak-constraint four-dimensional variational data assimilation

We examined biases in the global GEOS-Chem chemical transport model for the period of February–May 2010 using weak-constraint (WC) four-dimensional variational (4D-Var) data assimilation and dry-air mole fractions of CH$_{4}$ (XCH$_{4}$) from the Greenhouse gases Observing SATellite (GOSAT). The ability of the observations and the WC 4D-Var method to mitigate model errors in CH$_{4}$ concentrations was first investigated in a set of observing system simulation experiments (OSSEs). We then assimilated the GOSAT XCH$_{4}$ retrievals and found that they were capable of providing information on the vertical structure of model errors and of removing a significant portion of biases in the modeled CH$_{4}$ state. In the WC 4D-Var assimilation, corrections were added to the modeled CH$_{4}$ state at each model time step to account for model errors and improve the model fit to the assimilated observations. Compared to the conventional strong-constraint (SC) 4D-Var assimilation, the WC method was able to significantly improve the model fit to independent observations. Examination of the WC state corrections suggested that a significant source of model errors was associated with discrepancies in the model CH$_{4}$ in the stratosphere. The WC state corrections also suggested that the model vertical transport in the troposphere at middle and high latitudes is too weak. The problem was traced back to biases in the uplift of CH$_{4}$ over the source regions in eastern China and North America. In the tropics, the WC assimilation pointed to the possibility of biased CH$_{4}$ outflow from the African continent to the Atlantic in the mid-troposphere. The WC assimilation in this region would greatly benefit from glint observations over the ocean to provide additional constraints on the vertical structure of the model errors in the tropics. We also compared the WC assimilation at 4° × 5° and 2° × 2.5° horizontal resolutions and found that the WC corrections to mitigate the model errors were significantly larger at 4° × 5° than at 2° × 2.5° resolution, indicating the presence of resolution-dependent model errors. Our results illustrate the potential utility of the WC 4D-Var approach for characterizing model errors. However, a major limitation of this approach is the need to better characterize the specified model error covariance in the assimilation scheme