104 research outputs found
A "time when principles make best politics"? : the United States' response to the genocide in East Pakistan
On 25 March 1971, fearing the secession of East Pakistan, the military dictator, President Yahya Khan unleashed his country's West-Pakistani-dominated armed forces in a brutal campaign of massacre and repression in the East. During nine months of operations, the army butchered at least one million people. Though very much aware of the nature of the atrocities in East Pakistan, and despite vociferous public criticism at home, the US Government not only refused to intervene militarily and economically, but also failed to publicly condemn the actions of the Islamabad authorities. President Richard Nixon and his National Security Adviser, Henry Kissinger, dominated the formulation of US foreign policy at the time of the crisis. In his memoirs, Kissinger argued that US inaction throughout the emergency was justified on the grounds that Yahya was acting as the main channel for secret communications in a major strategic initiative aimed at securing rapprochement between the US and China. In the absence of much important primary-source material, secondary works have perpetuated this view. In contrast, using evidence from recently declassified documents, this thesis argues that the initial US reaction was divided into two phases. Only after 27 April 1971, when it sprang fully into life, did the secret China initiative come to dominate Nixon and Kissinger's policy. Up until this watershed event, however, a complex mixture of more mundane motives drove the US response. This revisionist posture, therefore, directly contradicts Kissinger's contentio
Transport behavior of holes in boron delta-doped diamond structures
Boron delta-doped diamond structures have been synthesized using microwave plasma chemical vapor deposition and fabricated into FET and gated Hall bar devices for assessment of the electrical characteristics. A detailed study of variable temperature Hall, conductivity, and field-effect mobility measurements was completed. This was supported by Schr€dinger-Poisson and relaxation time o calculations based upon application of Fermi’s golden rule. A two carrier-type model was developed with an activation energy of 1 cm2/Vs and the bulk valence band with high mobility. This new understanding of the transport of holes in such boron delta-doped structures has shown that although Hall mobility as high as 900 cm2/Vs was measured at room temperature, this dramatically overstates the actual useful performance of the device
Modulating autophagy as a therapeutic strategy for the treatment of paediatric high‐grade glioma
Paediatric high grade glioma (pHGG) represent a therapeutically challenging group of tumours. Despite decades of research there has been a minimal improvement in treatment and the clinical prognosis remains poor. Autophagy, a highly conserved process for recycling metabolic substrates is upregulated in pHGG, promoting tumour progression and evading cell death. There is significant cross talk between autophagy and a plethora of critical cellular pathways, many of which Accepted Article This article is protected by copyright. All rights reserved. are dysregulated in pHGG. The following article will discuss our current understanding of autophagy signalling in pHGG and the potential modulation of this network as a therapeutic target
Nano-structured morphological features of pulsed direct current magnetron sputtered Mo films for photovoltaic applications
Historically, molybdenum thin films have been used as the back contact for Cu(In,Ga)Se2 based solar cells and as such the properties of these layers play an important role in the overall cell structure. This paper describes the production of molybdenum films using pulsed d.c magnetron sputtering from compressed molybdenum powder targets. The films were deposited at different substrate temperatures under constant power and constant current modes, and analysed using X-ray diffraction, scanning electron microscopy, atomic force microscopy and four point resistance probe. Mechanical strain and resistivity were found to decrease with substrate temperature together with a shift in the (110) crystallographic plane towards higher diffraction angles. All films were well adhered to the glass substrates irrespective of their high tensile strain. Surface morphology analysis revealed the presence of nano-structured stress relief patterns which can enhance the nucleation sites for subsequent CuInSe2 deposition. A high-resolution cross sectional image showed the columnar growth of the films. Surface roughness analysis revealed that roughness increased with increase in substrate temperature
trans-Bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato-κ2 O,O′)bis(4-methyl-1,2,3-selenadiazole-κN 3)copper(II)
In the title compound, [Cu(C5HF6O2)2(C3H4N2Se)2], the CuII atom (site symmetry ) is coordinated by two O,O′-bidentate 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (hp) ligands and two 4-methyl-1,2,3-selenadiazole molecules, resulting in a slightly distorted trans-CuN2O4 octahedral geometry in which the cis angles deviate by less than 3° from 90°. The selenadiazole plane is canted at 73.13 (17)° to the square plane defined by the pentanedionate O atoms. The F atoms of one of the hp ligands are disordered over two sets of sites in a 0.66 (3):0.34 (3) ratio. There are no significant intermolecular interactions in the crystal
Impact of simulated nitrogen pollution on heathland microfauna, mesofauna and plants
Deposition of reactive nitrogen derived from intensive agriculture and industrial processes is a major threat to biodiversity and ecosystem services around the world; however our knowledge of the impacts of nitrogen is restricted to a very limited range of organisms. Here we examine the response of groups of microfauna (testate amoebae), mesofauna (enchytraeid worms) and plants to ammonium nitrate application in the Ruabon heathland long-term experiment. Plant data showed significant differences between treatments, particularly characterised by a loss of bryophytes in nitrogen-treated plots, by contrast enchytraeids showed a non-significant increase in abundance in response to treatment. Testate amoebae showed no significant changes in abundance or inferred biomass but significant changes in community structure with a reduced abundance of Corythion dubium, interpreted as a response to the loss of bryophytes. Our results suggest that simple indices of plant community may have value for bioindication while the bioindication value of testate amoebae and enchytraeids is not clearly demonstrated
The chemical evolution of the solar neighbourhood for planet-hosting stars
Theoretical physical-chemical models for the formation of planetary systems
depend on data quality for the Sun's composition, that of stars in the solar
neighbourhood, and of the estimated "pristine" compositions for stellar
systems. The effective scatter and the observational uncertainties of elements
within a few hundred parsecs from the Sun, even for the most abundant metals
like carbon, oxygen and silicon, are still controversial. Here we analyse the
stellar production and the chemical evolution of key elements that underpin the
formation of rocky (C, O, Mg, Si) and gas/ice giant planets (C, N, O, S). We
calculate 198 galactic chemical evolution (GCE) models of the solar
neighbourhood to analyse the impact of different sets of stellar yields, of the
upper mass limit for massive stars contributing to GCE () and of
supernovae from massive-star progenitors which do not eject the bulk of the
iron-peak elements (faint supernovae). Even considering the GCE variation
produced via different sets of stellar yields, the observed dispersion of
elements reported for stars in the Milky Way disk is not reproduced. Among
others, the observed range of super-solar [Mg/Si] ratios, sub-solar [S/N], and
the dispersion of up to 0.5 dex for [S/Si] challenge our models. The impact of
varying depends on the adopted supernova yields. Thus,
observations do not provide a constraint on the M parametrization.
When including the impact of faint supernova models in GCE calculations,
elemental ratios vary by up to 0.1-0.2 dex in the Milky Way disk; this
modification better reproduces observations.Comment: 36 pages, 26 figures, 1 Table, 1 Appendix, Accepted for publication
in MNRA
The New Generation Atlas of Quasar Spectral Energy Distributions from Radio to X-rays
We have produced the next generation of quasar spectral energy distributions
(SEDs), essentially updating the work of Elvis et al. (1994) by using
high-quality data obtained with several space and ground-based telescopes,
including NASA's Great Observatories. We present an atlas of SEDs of 85
optically bright, non-blazar quasars over the electromagnetic spectrum from
radio to X-rays. The heterogeneous sample includes 27 radio-quiet and 58
radio-loud quasars. Most objects have quasi-simultaneous ultraviolet-optical
spectroscopic data, supplemented with some far-ultraviolet spectra, and more
than half also have Spitzer mid-infrared IRS spectra. The X-ray spectral
parameters are collected from the literature where available. The radio,
far-infrared, and near-infrared photometric data are also obtained from either
the literature or new observations. We construct composite spectral energy
distributions for radio-loud and radio-quiet objects and compare these to those
of Elvis et al., finding that ours have similar overall shapes, but our
improved spectral resolution reveals more detailed features, especially in the
mid and near-infrared.Comment: 46 pages, 10 figures, 10 tables, Accepted by ApJS. Composite SED data
files for radio-loud and radio-quiet quasars (rlmsedMR.txt, rqmsedMR.txt) are
included in the source (Other formats -> Source). Supplemental figures are
not include
Comparative gene expression profiling of ADAMs, MMPs, TIMPs, EMMPRIN, EGF-R and VEGFA in low grade meningioma
MMPs (matrix metalloproteinases), ADAMs (a disintegrin and metalloproteinase) and TIMPs (tissue inhibitors of metalloproteinases) are implicated in invasion and angiogenesis: both are tissue remodeling processes involving regulated proteolysis of the extracellular matrix, growth factors and their receptors. The expression of these three groups and their correlations with clinical behaviour has been reported in gliomas but a similar comprehensive study in meningiomas is lacking. In the present study, we aimed to evaluate the patterns of expression of 23 MMPs, 4 TIMPs, 8 ADAMs, selective growth factors and their receptors in 17 benign meningiomas using a quantitative real-time polymerase chain reaction (qPCR). Results indicated very high gene expression of 13 proteases, inhibitors and growth factors studied: MMP2 and MMP14, TIMP-1, -2 and -3, ADAM9, 10, 12, 15 and 17, EGF-R, EMMPRIN and VEGF-A, in almost every meningioma.
Expression pattern analysis showed several positive correlations between MMPs, ADAMs, TIMPs and growth factors. Furthermore, our findings suggest that expression of MMP14, ADAM9, 10, 12, 15 and 17, TIMP-2, EGF-R and EMMPRIN reflects histological subtype of meningioma such that fibroblastic subtype had the highest mRNA expression, transitional subtype was intermediate and meningothelial type had the lowest expression. In conclusion, this is the first comprehensive study characterizing gene expression of ADAMs in meningiomas. These neoplasms, although by histological definition benign, have invasive potential. Taken together, the selected elevated gene expression pattern may serve to identify targets for therapeutic intervention or indicators of biological progression and recurrence
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