A practical multi-spectrum Hadamard Transform Spectrometer

A Hadamard Transform Spectrometer (HTS) which simultaneously obtains fifteen infrared spectra, each having 255 spectral elements was constructed. Spectra are obtained essentially in real time through use of a minicomputer with 8K words of memory and a CRT display. This permits operation of the instrument in the field

Partial DNA Assembly: A Rate-Distortion Perspective

Earlier formulations of the DNA assembly problem were all in the context of perfect assembly; i.e., given a set of reads from a long genome sequence, is it possible to perfectly reconstruct the original sequence? In practice, however, it is very often the case that the read data is not sufficiently rich to permit unambiguous reconstruction of the original sequence. While a natural generalization of the perfect assembly formulation to these cases would be to consider a rate-distortion framework, partial assemblies are usually represented in terms of an assembly graph, making the definition of a distortion measure challenging. In this work, we introduce a distortion function for assembly graphs that can be understood as the logarithm of the number of Eulerian cycles in the assembly graph, each of which correspond to a candidate assembly that could have generated the observed reads. We also introduce an algorithm for the construction of an assembly graph and analyze its performance on real genomes.Comment: To be published at ISIT-2016. 11 pages, 10 figure

Uncertainties in stellar evolution models: convective overshoot

In spite of the great effort made in the last decades to improve our understanding of stellar evolution, significant uncertainties remain due to our poor knowledge of some complex physical processes that require an empirical calibration, such as the efficiency of the interior mixing related to convective overshoot. Here we review the impact of convective overshoot on the evolution of stars during the main Hydrogen and Helium burning phases.Comment: Proc. of the workshop "Asteroseismology of stellar populations in the Milky Way" (Sesto, 22-26 July 2013), Astrophysics and Space Science Proceedings, (eds. A. Miglio, L. Girardi, P. Eggenberger, J. Montalban

Water retention and shrinkage curves of weathered pyroclastic soil

The modelling of the triggering mechanism of rainfall-induced landslides in slopes covered by pyroclastic soil (as the area surrounding Mount Vesuvius in Campania, Italy) requires the hydraulic characterization of soil in unsaturated conditions in order to analyse the slope response to rainfalls. In previous studies carried out on Campanian pyroclastic soils, the volumetric soil changes due to suction changes have been disregarded, being them negligible in soils characterized by low plasticity and low clay contents. However, a more accurate determination of the water retention curve (WRC) in terms of volumetric water content requires a correct estimation of the total soil volume, which is affected by the soil stress-state. The proper approach would require the estimation of both WRC in terms of gravimetric water content and the shrinkage curve (SC). In the present study, a relation between void ratio and suction was determined for a pyroclastic soil sampled at Mount Faito in Southern Italy. Therefore, a correction of the volumetric water content was carried out resulting in updated water retention curves. Here, the matric suction was the only factor affecting the stress-state of the soil

The Role of Thyrotrophin Receptor Antibody Assays in Graves' Disease

Thyrotrophin receptor antibodies (TRAb) exist as stimulating or blocking antibodies in the serum (neutral TRAb have been identified recently). The clinical features of GD occur when stimulating TRAb predominate. But the relationship of TRAb to clinical phenotype and outcome is not clear when current assay methods are used. Therefore no consensus exists about its utility in diagnosing and predicting outcome in GD. The most commonly used TRAb assays, measure thyroid binding inhibiting immunoglobulins (TBII or “receptor assays”) and don't differentiate between stimulating and blocking antibodies. However, the more expensive, technically demanding and less freely available “biological assays” differentiate between them by their ability to stimulate cyclic AMP or failure to do so. Failure to differentiate between TRAb types and its heterogeneous molecular and functional properties has limited TBII use to GD diagnosis and differentiating from other forms of thyrotoxicosis. The current 2nd-3rd generation receptor assays are highly sensitive and specific when used for this purpose. TRAb assays should also be done in appropriate pregnant women. Current data do not support its use in outcome prediction as there is a significant variability of assay methodology, population characteristics and study design in published data, resulting in a lack of consensus

The energy-momentum tensor,the trace identity and the Casimir effect

The trace identity associated with the scale transformation x^\mu\tox'{}^\mu = e^{-\rho}x^\mu on the Lagrangian density for the noninteracting electromagnetic field in the covariant gauge is shown to be violated on a single plate on which the Dirichlet boundary condition $A^\mu(t,x^1,x^2,x^3=-a) = 0$ is imposed.It is however respected in free space,i.e. in the absence of the plate; these results reinforce our assertions in an earlier paper where the same exercise was carried out using the Lagrangian density for the free,massive,real scalar field in 2 + 1 dimensions.Comment: 22 page

Nature, Data, And Power: How Hegemonies Shaped This Special Section

Systems of oppression—racism, colonialism, misogyny, cissexism, ableism, heteronormativity, and more—have long shaped the content and practice of science. But opportunities to reckon with these influences are rarely found within academic science, even though such critiques are well developed in the social sciences and humanities. In this special section, we attempt to bring cross-disciplinary conversations among ecology, evolution, behavior, and genetics on the one hand and critical perspectives from the social sciences and humanities on the other into the pages—and in front of the readers—of a scientific journal. In this introduction to the special section, we recount and reflect on the process of running this cross-disciplinary experiment to confront harms done in the name of science and envision alternatives

Multi-wavelength VLTI study of the puffed-up inner rim of a circumbinary disc

The presence of stable, compact circumbinary discs of gas and dust around post-asymptotic giant branch (post-AGB) binary systems has been well established. We focus on one such system: IRAS 08544-4431. We present an interferometric multi-wavelength analysis of the circumstellar environment of IRAS 08544-4431. The aim is to constrain different contributions to the total flux in the H, K, L, and N-bands in the radial direction. The data from VLTI/PIONIER, VLTI/GRAVITY, and VLTI/MATISSE range from the near-infrared, where the post-AGB star dominates, to the mid-infrared, where the disc dominates. We fitted two geometric models to the visibility data to reproduce the circumbinary disc: a ring with a Gaussian width and a flat disc model with a temperature gradient. The flux contributions from the disc, the primary star (modelled as a point-source), and an over-resolved component are recovered along with the radial size of the emission, the temperature of the disc as a function of radius, and the spectral dependencies of the different components. The trends of all visibility data were well reproduced with the geometric models. The near-infrared data were best fitted with a Gaussian ring model while the mid-infrared data favoured a temperature gradient model. This implies that a vertical structure is present at the disc inner rim, which we attribute to a rounded puffed-up inner rim. The N-to-K size ratio is 2.8, referring to a continuous flat source, analogues to young stellar objects. By combining optical interferometric instruments operating at different wavelengths we can resolve the complex structure of circumstellar discs and study the wavelength-dependent opacity profile. A detailed radial, vertical, and azimuthal structural analysis awaits a radiative transfer treatment in 3D to capture all non-radial complexity.Comment: 8 pages, 5 figures, accepted for publication in A&A Letter