39 research outputs found
Cadmium and lead accumulate in the deciduous teeth of children with celiac disease or food allergies
Observational constraints on the dark energy density evolution
We constrain the evolution of the dark energy density from Cosmic Microwave
Background, Large Scale Structure and Supernovae Ia measurements. While
Supernovae Ia are most sensitive to the equation of state of dark energy
today, the Cosmic Microwave Background and Large Scale Structure data best
constrains the dark energy evolution at earlier times. For the parametrization
used in our models, we find and the dark energy fraction at very
high redshift at 95 per cent confidence level.Comment: 5 pages, 10 figure
Pashto Border Literature as Geopolitical Knowledge
In this article I read a selection of Pashto literatures as critical thought about geopolitics. Drawing on Michael Shapiro’s concept of aesthetic subjects, as well as on border theory, I argue that the authors, the content, and the literary networks of these works all comment on global relations of power, ranging from the local bordering effects of geopolitics, to systems of knowledge embedded in the spatiality and temporality of empire. I argue that past and current imperial processes have led to fragmenting effects in Afghan society, and literature both reflects and analyzes this. Beyond that, I argue—through the examples of authors’ lives as well as their work—that literary activity in Pashto has actively negotiated such processes throughout its history, and offers strategies for countervailing notions of global connectivity in action as well as thought. The decentralized and multiperspective images of life in these works sit in counterpoint not only to the systems-oriented views that drive military and other policy in Afghanistan during the ongoing US moment, but also to universalist perspectives upon which disciplines like world history and geopolitics traditionally rely. Additionally, though, Pashto literary networks themselves also produce alternative structures. This contributes to the aesthetic turn in IR by arguing that it is not only the aesthetic vision in works that challenges dominant knowledge; the shape of the Pashto literary formation itself, organic with its content, is an alternate form of knowledge-in-practice about the contemporary world
Randomly generated polytopes for testing mathematical programming algorithms
Randomly generated polytopes are used frequently to test and compare algorithms for a variety of mathematical programming problems. These polytopes are constructed by generating linear inequality constraints with coefficients drawn independently from a distribution such as the uniform or the normal.
It is noted that this class of 'random' polytopes has a special property: the angles between the hyperplanes, though dependent on the specific distribution used, tend to be equal when the dimension of the space increases. Obviously this structure of 'random' polytopes may bias test results
On generalized surrogate duality in mixed-integer nonlinear programming
The most important ingredient for solving mixed-integer nonlinear programs (MINLPs) to global -optimality with spatial branch and bound is a tight, computationally
tractable relaxation. Due to both theoretical and practical considerations, relaxations of MINLPs are usually required to be convex. Nonetheless, current optimization solvers
can often successfully handle a moderate presence of nonconvexities, which opens the door for the use of potentially tighter nonconvex relaxations. In this work, we
exploit this fact and make use of a nonconvex relaxation obtained via aggregation of constraints: a surrogate relaxation. These relaxations were actively studied for linear integer programs in the 70s and 80s, but they have been scarcely considered since. We revisit these relaxations in an MINLP setting and show the computational benefits and
challenges they can have. Additionally, we study a generalization of such relaxation that allows for multiple aggregations simultaneously and present the first algorithm that is capable of computing the best set of aggregations. We propose a multitude of computational enhancements for improving its practical performance and evaluate the
algorithm’s ability to generate strong dual bounds through extensive computational experiments
Characterization of Si-Membrane TES Bolometer Arrays for the HIRMES Instrument
The High Resolution Mid-Infrared Spectrometer (HIRMES) instrument will fly onboard NASA's airborne Stratospheric Observatory for Infrared Astronomy (SOFIA) in 2019. HIRMES will provide astronomers with a unique observing window (25 122 m) for exploring the evolution of protoplanetary disks into young solar systems, and the composition of our Solar System. There are two focal plane detector arrays for the instrument: a high-resolution (/ = 100,000) 8x16 detector array with a target noise-equivalent power, NEP 3x10-18 W/Hz; and a low-resolution (/ = 2,000 19,000) 16x64 detector array with a target NEP 2x10-17 W/Hz. The detectors for both of these arrays are superconducting Mo/Au bilayer transition edge sensor (TES) bolometers on thin suspended single-crystal silicon membranes. Here we present our characterization results for the detectors in both arrays, including measurements of thermal conductance with comparison to phonon transport models, saturation power, noise, and array uniformity
GLI1 Confers Profound Phenotypic Changes upon LNCaP Prostate Cancer Cells That Include the Acquisition of a Hormone Independent State
The GLI (GLI1/GLI2) transcription factors have been implicated in the development
and progression of prostate cancer although our understanding of how they
actually contribute to the biology of these common tumours is limited. We
observed that GLI reporter activity was higher in normal (PNT-2) and
tumourigenic (DU145 and PC-3) androgen-independent cells compared to
androgen-dependent LNCaP prostate cancer cells and, accordingly, GLI mRNA levels
were also elevated. Ectopic expression of GLI1 or the constitutively active
ΔNGLI2 mutant induced a distinct cobblestone-like morphology in LNCaP cells
that, regarding the former, correlated with increased GLI2 as well as expression
of the basal/stem-like markers CD44, β1-integrin, ΔNp63 and BMI1, and
decreased expression of the luminal marker AR (androgen receptor). LNCaP-GLI1
cells were viable in the presence of the AR inhibitor bicalutamide and gene
expression profiling revealed that the transcriptome of LNCaP-GLI1 cells was
significantly closer to DU145 and PC-3 cells than to control LNCaP-pBP (empty
vector) cells, as well as identifying LCN2/NGAL as a highly induced transcript
which is associated with hormone independence in breast and prostate cancer.
Functionally, LNCaP-GLI1 cells displayed greater clonal growth and were more
invasive than control cells but they did not form colonies in soft agar or
prostaspheres in suspension suggesting that they do not possess inherent stem
cell properties. Moreover, targeted suppression of GLI1 or GLI2 with siRNA did
not reverse the transformed phenotype of LNCaP-GLI1 cells nor did double
GLI1/GLI2 knockdowns activate AR expression in DU145 or PC-3 cells. As such,
early targeting of the GLI oncoproteins may hinder progression to a hormone
independent state but a more detailed understanding of the mechanisms that
maintain this phenotype is required to determine if their inhibition will
enhance the efficacy of anti-hormonal therapy through the induction of a luminal
phenotype and increased dependency upon AR function
Sediment source fingerprinting: benchmarking recent outputs, remaining challenges and emerging themes
Abstract: Purpose: This review of sediment source fingerprinting assesses the current state-of-the-art, remaining challenges and emerging themes. It combines inputs from international scientists either with track records in the approach or with expertise relevant to progressing the science. Methods: Web of Science and Google Scholar were used to review published papers spanning the period 2013–2019, inclusive, to confirm publication trends in quantities of papers by study area country and the types of tracers used. The most recent (2018–2019, inclusive) papers were also benchmarked using a methodological decision-tree published in 2017. Scope: Areas requiring further research and international consensus on methodological detail are reviewed, and these comprise spatial variability in tracers and corresponding sampling implications for end-members, temporal variability in tracers and sampling implications for end-members and target sediment, tracer conservation and knowledge-based pre-selection, the physico-chemical basis for source discrimination and dissemination of fingerprinting results to stakeholders. Emerging themes are also discussed: novel tracers, concentration-dependence for biomarkers, combining sediment fingerprinting and age-dating, applications to sediment-bound pollutants, incorporation of supportive spatial information to augment discrimination and modelling, aeolian sediment source fingerprinting, integration with process-based models and development of open-access software tools for data processing. Conclusions: The popularity of sediment source fingerprinting continues on an upward trend globally, but with this growth comes issues surrounding lack of standardisation and procedural diversity. Nonetheless, the last 2 years have also evidenced growing uptake of critical requirements for robust applications and this review is intended to signpost investigators, both old and new, towards these benchmarks and remaining research challenges for, and emerging options for different applications of, the fingerprinting approach