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Light-curve inversion is an established technique in determining the shape and spin states of an asteroid. However, the front part of the processing pipeline, which recovers the spin pole and area of each facet, is a non-convex optimization problem. Hence, any local iterative optimization scheme can only promise a locally optimal solution. Apart from the obvious downsides of getting a non-optimal solution and the need for an initialization scheme, another major implication is that it creates an ambiguous scenario – which is to be blamed for the remaining residual? The inaccuracy of the modelling, the integrity of the data, or the non-global algorithm? We address the last uncertainty in this paper by embedding the spin pole and area vector determination module in a deterministic global optimization framework. To the best of our knowledge, this is the first attempt to solve these parameters globally. Specifically, given calibrated light-curve data, a scattering model for the object, and spin period, our method outputs the globally optimal spin pole and area vector solutions. One theoretical contribution of this paper is the introduction of a lower bound error function that is derived based on (1) the geometric relationship between the incident and scattered light on a surface and (2) the uncertainty of the gap between the observed and estimated brightness at a particular epoch in a light curve. We validated our method's ability in achieving global minimum with both simulated and real light-curve data. We also tested our method on the real light curves of four asteroids. [ABSTRACT FROM AUTHOR]

We test the adequacy of ultraviolet (UV) spectra for characterizing the outer structure of Type Ia supernova (SN) ejecta. For this purpose, we perform spectroscopic analysis for ASASSN-14lp, a normal SN Ia showing low continuum in the mid-UV regime. To explain the strong UV suppression, two possible origins have been investigated by mapping the chemical profiles over a significant part of their ejecta. We fit the spectral time series with mid-UV coverage obtained before and around maximum light by HST , supplemented with ground-based optical observations for the earliest epochs. The synthetic spectra are calculated with the one-dimensional MC radiative transfer code tardis from self-consistent ejecta models. Among several physical parameters, we constrain the abundance profiles of nine chemical elements. We find that a distribution of 56Ni (and other iron-group elements) that extends towards the highest velocities reproduces the observed UV flux well. The presence of radioactive material in the outer layers of the ejecta, if confirmed, implies strong constraints on the possible explosion scenarios. We investigate the impact of the inferred 56Ni distribution on the early light curves with the radiative transfer code turtls , and confront the results with the observed light curves of ASASSN-14lp. The inferred abundances are not in conflict with the observed photometry. We also test whether the UV suppression can be reproduced if the radiation at the photosphere is significantly lower in the UV regime than the pure Planck function. In this case, solar metallicity might be sufficient enough at the highest velocities to reproduce the UV suppression. [ABSTRACT FROM AUTHOR]

The existence of multiple subclasses of Type Ia supernovae (SNe Ia) has been the subject of great debate in the last decade. One major challenge inevitably met when trying to infer the existence of one or more subclasses is the time consuming, and subjective, process of subclass definition. In this work, we show how machine learning tools facilitate identification of subtypes of SNe Ia through the establishment of a hierarchical group structure in the continuous space of spectral diversity formed by these objects. Using deep learning, we were capable of performing such identification in a four-dimensional feature space (+1 for time evolution), while the standard principal component analysis barely achieves similar results using 15 principal components. This is evidence that the progenitor system and the explosion mechanism can be described by a small number of initial physical parameters. As a proof of concept, we show that our results are in close agreement with a previously suggested classification scheme and that our proposed method can grasp the main spectral features behind the definition of such subtypes. This allows the confirmation of the velocity of lines as a first-order effect in the determination of SN Ia subtypes, followed by 91bg-like events. Given the expected data deluge in the forthcoming years, our proposed approach is essential to allow a quick and statistically coherent identification of SNe Ia subtypes (and outliers). All tools used in this work were made publicly available in the PYTHON package Dimensionality Reduction And Clustering for Unsupervised Learning in Astronomy (DRACULA) and can be found within COINtoolbox. [ABSTRACT FROM AUTHOR]

We have assembled a data set of 165 low redshift, z < 0.06, publicly available Type Ia supernovae (SNe Ia). We produce maximum light magnitude (MB and MV) distributions of SNe Ia to explore the diversity of parameter space that they can fill. Before correction for host galaxy extinction we find that the mean MB and MV of SNe Ia are -18.58 ± 0.07 and -18.72 ± 0.05 mag, respectively. Host galaxy extinction is corrected using a new method based on the SN spectrum. After correction, the mean values of MB and MV of SNe Ia are -19.10 ± 0.06 and -19.10 ± 0.05 mag, respectively. After correction for host galaxy extinction, 'normal' SNe Ia (Δm15(B) < 1.6 mag) fill a larger parameter space in the width-luminosity relation than previously suggested, and there is evidence for luminous SNe Ia with large Δm15(B). We find a bimodal distribution in Δm15(B), with a pronounced lack of transitional events at Δm15(B) = 1.6 mag. We confirm that faster, low-luminosity SNe tend to come from passive galaxies. Dividing the sample by host galaxy type, SNe Ia from star-forming (S-F) galaxies have a mean MB = -19.20 ± 0.05 mag, while SNe Ia from passive galaxies have a mean MB = -18.57 ± 0.24 mag. Even excluding fast declining SNe, 'normal' (MB < -18 mag) SNe Ia from S-F and passive galaxies are distinct. In the V band, there is a difference of 0.4 ± 0.13 mag between the median (MV) values of the 'normal' SN Ia population from passive and S-F galaxies. This is consistent with (~15 ± 10) per cent of 'normal' SNe Ia from S-F galaxies coming from an old stellar population. [ABSTRACT FROM AUTHOR]

A new method to study the intrinsic colour and luminosity of Type Ia supernovae (SNe Ia) is presented. A metric space built using principal component analysis on a spectral series for SNe Ia between -12.5 and +17.5 d from the B maximum is used as a set of predictors. This metric space is built to be insensitive to reddening. Hence, it does not predict the part of the colour excess due to dust extinction. At the same time, the rich variability of SN Ia spectra is a good predictor of a large fraction of the intrinsic colour variability. Such a metric space is a good predictor of the epoch when the maximum in the B - V colour curve is reached. Multivariate partial least-squares regression predicts the intrinsic B-band light curve and the intrinsic B - V colour curve up to a month after the maximum. This allows us to study the relation between the light curves of SNe Ia and their spectra. The total-to-selective extinction ratio RV in the host galaxy of SNe Ia is found, on average, to be consistent with typical Milky Way values. This analysis shows the importance of collecting spectra to study SNe Ia, even with a large sample publicly available. Future automated surveys, such as the Large Synoptic Survey Telescope, will provide a large number of light curves. The analysis shows that observing accompanying spectra for a significant number of SNe will be important even for normal SNe Ia. [ABSTRACT FROM AUTHOR]

We develop a new framework for use in exploring Type Ia supernovae (SNe Ia) spectra. Combining principal component analysis (PCA) and partial least square (PLS) analysis we are able to establish correlations between the principal components (PCs) and spectroscopic/photometric SNe Ia features. The technique was applied to ~120 SN and~800 spectra from the Nearby Supernova Factory. The ability of PCA to group together SNe Ia with similar spectral features, already explored in previous studies, is greatly enhanced by two important modifications: (1) the initial data matrix is built using derivatives of spectra over the wavelength, which increases the weight of weak lines and discards extinction, and (2) we extract time evolution information through the use of entire spectral sequences concatenated in each line of the input data matrix. These allow us to define a stable PC parameter space which can be used to characterize synthetic SN Ia spectra by means of real SN features. Using PLS, we demonstrate that the information fromimportant previously known spectral indicators (namely the pseudo-equivalent width of Si II 5972Å/Si II 6355Å and the line velocity of S II 5640Å/Si II 6355Å) at a given epoch is contained within the PC space and can be determined through a linear combination of the most important PCs. We also show that the PC space encompasses photometric features like B V magnitudes, B - V colours and SALT2 parameters c and x1. The observed colours and magnitudes, which are heavily affected by extinction, cannot be reconstructed using this technique alone. All the above-mentioned applications allowed us to construct a metric space for comparing synthetic SN Ia spectra with observations. [ABSTRACT FROM AUTHOR]

The abundance distribution of the elements in the ejecta of the peculiar, luminous Type Ia supernova (SN Ia) 1991T is obtained modelling spectra from before maximum light until a year after the explosion, with the method of ‘Abundance Tomography’. SN 1991T is different from other slowly declining SNe Ia (e.g. SN 1999ee) in having a weaker Si ii 6355 line and strong features of iron group elements before maximum. The distance to the SN is investigated along with the abundances and the density profile. The ionization transition that happens around maximum sets a strict upper limit on the luminosity. Both W7 and the WDD3 delayed detonation models are tested. WDD3 is found to provide marginally better fits. In this model the core of the ejecta is dominated by stable Fe with a mass of about 0.15 M⊙, as in most SNe Ia. The layer above is mainly 56Ni up to v ∼ 10 000 km s−1 (≈0.78 M⊙). A significant amount of 56Ni (∼3 per cent) is located in the outer layers. A narrow layer between 10 000 km s−1 and ∼12 000 km s−1 is dominated by intermediate-mass elements (IME), ∼0.18 M⊙. This is small for a SN Ia. The high luminosity and the consequently high ionization, and the high 56Ni abundance at high velocities, explain the peculiar early-time spectra of SN 1991T. The outer part is mainly of oxygen, ∼0.3 M⊙. Carbon lines are never detected, yielding an upper limit of 0.01 M⊙ for C. The abundances obtained with the W7 density model are qualitatively similar to those of the WDD3 model. Different elements are stratified with moderate mixing, resembling a delayed detonation. [ABSTRACT FROM PUBLISHER]

Aims: Although an organizational model for syncope management facilities was proposed in the 2004 guidelines of the European Society of Cardiology (ESC), its implementation in clinical practice and its effectiveness are largely unknown.Methods and Results: This prospective study enrolled 941 consecutive patients referred to the Syncope Units of nine general hospitals from 15 March 2008 to 15 September 2008. A median of 15 patients per month were examined in each unit, but the five older units had a two-fold higher volume of activity than the four newer ones (instituted <1 year before): 23 vs. 12, P = 0.02. These figures give an estimated volume of 163 and 60 patients per 100,000 inhabitants per year, respectively. Referrals: 60% from out-of-hospital services, 11% immediate and 13% delayed referrals from the Emergency Department, and 16% hospitalized patients. A diagnosis was established on initial evaluation in 191 (21%) patients and early by means of 2.9 +/- 1.6 tests in 541 (61%) patients. A likely reflex cause was established in 67%, orthostatic hypotension in 4%, cardiac in 6% and non-syncopal in 5% of the cases. The cause of syncope remained unexplained in 159 (18%) patients, despite a mean of 3.5 +/- 1.8 tests per patient. These latter patients were older, more frequently had structural heart disease or electrocardiographic abnormalities, unpredictable onset of syncope due to the lack of prodromes, and higher OESIL and EGSIS risk scores than the other groups of patients. The mean costs of diagnostic evaluation was 209 euro per outpatient and 1073 euro per inpatient. The median cost of hospital stay was 2990 euro per patient.Conclusion: We documented the current practice of syncope management in specialized facilities that have adopted the management model proposed by the ESC. The results are useful for those who wish to replicate this model in other hospitals. Syncope remains unexplained during in-hospital evaluation in more complex cases at higher risk. [ABSTRACT FROM AUTHOR]

Various recent reports have suggested the presence of a functional defect of lymphocyte subpopulations in minimal-change nephropathy during the active phase. A probable role of inhibitory humoral factor(s) has been hypothesized. However, other authors have been unable to detect a significant difference between plasma from patients with nephrotic syndrome due to minimal-change nephropathy and plasma from other glomerulonephritis in the degree of inhibition of mitogen-induced lymphocyte transformation. In our study, T cell function, as measured by the response to PHA in autologous plasma, was depressed only in patients with minimal-change nephrotic syndrome and in patients with membranoproliferative glomerulonephritis. The lymphocyte function returned to normal when lymphocytes were cultured in homologous plasma. The lymphocyte responsiveness of patients with other glomerulonephritis with or without nephrotic syndrome was normal in both autologous and homologous plasma. Moreover, only plasma from patients with minimal-change nephropathy in the active phase and with membranoproliferative glomerulonephritis were able to induce inhibition of mitogenesis of lymphocytes from healthy donors. These data seem to confirm the presence of specific humoral inhibitory factor(s) in the plasma of these patients. Finally, preliminary findings seem to demonstrate an increase of the number of To cells in patients with minimal-change nephropathy in remission who relapse early in the subsequent follow-up. [ABSTRACT FROM AUTHOR]

A multicentre, randomized, placebo-controlled study was performed in 39 adult patients with biopsy-proven IgA nephropathy with the aim of comparing the effects of the ACE inhibitor fosinopril and placebo on proteinuria. All patients had normal blood pressure and normal renal function. Proteinuria ranged from 1.0 to 2.5 g/24 h. After a 3-month run-in period, fosinopril and placebo were randomly administered in two 4-month sequences separated from crossover treatment by a 1-month interval. The mean values of creatinine clearance did not change during either the placebo or the treatment sequences. The mean values of mean arterial pressure (MAP) were significantly lower during the fosinopril sequence (90.4 ±9.0 mmHg) than in basal conditions (92.8 ± 9.1 mmHg) (=0.034). The mean basal values of proteinuria were 1.74 ±0.84 g/24 h. They were unchanged during the placebo sequence (1.79 ±1.20) and fell to 1.37 ±0.98 g/24 h after 4 months of fosinopril treatment. Using a multivariate statistical analysis, the treatment effect by time on proteinuria was significantly evident only in the fosinopril sequence (Wilks test, =O.O33). Changes in protein excretion were not correlated with changes in MAP, baseline plasma renin activity, and urinary sodium excretion. This controlled study shows that fosinopril can significantly reduce proteinuria even in normotensive patients with IgA nephropathy. Obviously, the results of treatment with ACE inhibitors on long-term renal prognosis remain to be elucidated. [ABSTRACT FROM PUBLISHER]

Peripheral blood lymphocytes from 15 healthy controls and 59 patients with idiopathic glomerulonephdtis were studied to determine whether an imbalance exists among human T cell subsets in these diseases. Twenty of the patients studied had a minimal change nephropathy (10 with nephrotic syndrome and 10 in sustained remission); 27 had a membranous glomerulonephritis (12 with nephrotic syndrome, six with isolated proteinuria and nine in complete remission); 12 patients had an IgA glomerulonephritis with heamaturia and mild proteinuria. Monoclonal antibodies directed at human T lymphocyte subsets termed OKT3, OKT4 and OKT8 were used in an indirect immunofluorescence assay in all cases. Patients with minimal change nephropathy, with or without nephrotic syndrome and patients with IgA glomerulonephritis showed mean values of OKT3+ cells (total peripheral T cells), helper OKT4+ cells, suppressor OKT8+ cells and OKT4+/OKT8+ cell ratio, in the normal range. Only the group of patients with membranous glomerulonephritis and nephrotic syndrome presented a mean OKT4+/OKT8+ ratio greater than the normal group (percentages: 2.43 ± 0.3 vs 1.6 ± 0.1 s.e.m,; P < 0.02), This increased ratio was due to a reduction in the OKT8+ cell subset compared to the healthy subjects (percentages: 27.6 ± 2.9 vs 36.8 ± 1.4 s.e.m.; P < 0.01). Our data shows that the functional lymphocyte disorders previously described in minimal change nephropathy and IgA glomerulonephritis are not due to a numerical imbalance of lymphocyte subsets. Such an imbalance of lymphocyte subsets was specifically observed in membranous glomerulonephritis with nephrotic syndrome. The true significance of this finding has to be clarified by longitudinal studies and functional tests. [ABSTRACT FROM AUTHOR]