Parting the bamboo curtain: The enigmatic political and strategic quest of Richard Nixon for detente with Communist China

President Richard Nixon\u27s decision to unofficially recognize Communist China during the early 1970s represented an apparently sudden political and strategic turnabout for both he and the United States. After decades of virulent anti-Communism upon which a meteoric political career was built, Nixon, faced with mounting domestic pressures to end the Vietnam War and the necessity of obtaining policy concessions from the Soviet Union, embarked upon a course of detente with Mainland China that seemed to completely contradict his hawkish, Cold Warrior image. Far from being a strictly political maneuver in the months leading to the 1972 presidential election, Nixon\u27s decision was instead a pragmatic, geopolitical strategy designed as much to pressure the U.S.S.R. and balance the power in Asia as it was to bring the Chinese back into the world community of nations. Richard Nixon\u27s conservative background made the decision and subsequent Peking summit possible, as did his diplomatic partnership with Henry Kissinger

SKA Engineering Change Proposal: Gridded Visibilities to Enable Precision Cosmology with Radio Weak Lensing

This document was submitted as supporting material to an Engineering Change Proposal (ECP) for the Square Kilometre Array (SKA). This ECP requests gridded visibilities as an extra imaging data product from the SKA, in order to enable bespoke analysis techniques to measure source morphologies to the accuracy necessary for precision cosmology with radio weak lensing. We also discuss the properties of an SKA weak lensing data set and potential overlaps with other cosmology science goals.Comment: Comments welcome. 4 pages, 3 figures. Progress can be tracked at the SKA ECP register https://skaoffice.atlassian.net/wiki/display/EP/ECP+Registe

A field study to assess the degradation and transport of diuron and its metabolites in a calcareous soil

An experimental plot has been established on a calcareous soil in southern England to investigate the fate and transport of diuron (N'-[3,4-dichlorophenyl]-NN-dimethylurea), a commonly used phenylurea herbicide. An agricultural grade of diuron was applied to the soil surface at a rate of 6.7 kg/ha along with a potassium bromide conservative tracer applied at 200 kg/ha, in early January, 2001. Hand augured samples were taken at regular intervals over the next 50 days, with samples collected down to 54 cm. Porewaters were extracted from the soil cores by using high speed centrifugation and the supernatant fluids were retained for analysis by HPLC, for diuron and three of its metabolites, N'-[3,4-dichlorophenyl]-N,N-methylurea (DCPMU), N'-3,4-dichlorophenylurea (DCPU) and 3,4-dichloroaniline (DCA). The centrifuged soil was retained and then extracted with methanol prior to HPLC analysis for the same suite of phenylureas. A mass balance approach showed large variations in diuron distribution, but on average accounted for 104% of the diuron applied. Concentrations of diuron and its metabolites were roughly five times higher in the soil than in the soil porewaters. After 50 days, metabolites comprised 10% of the total diuron present in the porewater and 20% of the total diuron sorbed to the soil matrix. After 36 days, a large pulse of diuron and DCPMU appeared in the porewaters and soil matrix at a depth of 54 cm, travelling an average of 0.15 cm/day faster than Br. A preferential route for diuron transport is suggested. There is evidence to suggest that degradation occurs at depth as well as at the soil surface. Metabolites generally appear to move more slowly than the parent compound. All metabolites were encountered, but interpreting transport and degradation processes simultaneously proved beyond the scope of the study. Diuron was detected once in a shallow (5 m) observation well, situated on the experimental plot. High concentrations of diuron and metabolites were still present in the soil and soil solutions after 50 days and remain as a source of potential groundwater contaminatio

Development of a knowledge-based system for open stope mine design

Imperial Users onl

Radio-Optical Galaxy Shape Correlations in the COSMOS Field

We investigate the correlations in galaxy shapes between optical and radio wavelengths using archival observations of the COSMOS field. Cross-correlation studies between different wavebands will become increasingly important for precision cosmology as future large surveys may be dominated by systematic rather than statistical errors. In the case of weak lensing, galaxy shapes must be measured to extraordinary accuracy (shear systematics of $< 0.01\%$) in order to achieve good constraints on dark energy parameters. By using shape information from overlapping surveys in optical and radio bands, robustness to systematics may be significantly improved without loss of constraining power. Here we use HST-ACS optical data, VLA radio data, and extensive simulations to investigate both our ability to make precision measurements of source shapes from realistic radio data, and to constrain the intrinsic astrophysical scatter between the shapes of galaxies as measured in the optical and radio wavebands. By producing a new image from the VLA-COSMOS L-band radio visibility data that is well suited to galaxy shape measurements, we are able to extract precise measurements of galaxy position angles. Comparing to corresponding measurements from the HST optical image, we set a lower limit on the intrinsic astrophysical scatter in position angles, between the optical and radio bands, of $\sigma_\alpha > 0.212\pi$ radians (or $38.2^{\circ}$) at a $95\%$ confidence level.Comment: 17 pages, 13 figure, 5 tables. Updated to match published version with a number of typographical correction

Investigating the neuroprotective effects of histone deacetylase inhibitors in Parkinson's Disease

Parkinson’s disease (PD) is the most common movement disorder and the second most common neurodegenerative disease affecting around 4 million people worldwide. Movement symptoms in PD are primarily due to degeneration of dopaminergic nigrostriatal neurons. These symptoms can be partially controlled by dopamine replacement therapies, however long term use of these drugs lead to debilitating side-effects and more importantly do not protect degenerating dopaminergic neurons from death. Hence novel neuroprotective strategies are sought. Recent evidence implicates αSynuclein accumulation, the hallmark of degenerating neurons in PD, with perturbed epigenetic acetylation of histone proteins around which DNA is coiled. A misbalance between the activities of the two enzyme classes responsible for control of histone acetylation, histone acetyltransferases and histone deacetylases (HDACs), have been linked to cell death in animal models of neurodegeneration. It is therefore hypothesised that if this pathogenic imbalance can be rectified with the use of HDAC inhibitors (HDACIs) then neurodegeneration observed in PD can be avoided. Here, the first evidence of altered histone acetylation and perturbed HDAC isoform expression in degenerating regions of the human Parkinsonian brain are demonstrated. Cell culture studies using dopaminergic neuronal and microglial cell lines demonstrate that dependent on the HDAC class(s) or isoform(s) inhibited, HDACIs are capable of inducing neuroprotection and reduction of microglial activation in vitro. Study of two broad-spectrum HDACIs in vivo, in the lactacystin rat model of PD demonstrate that, also dependent on isoform inhibition, HDACIs cause dose-dependent histone acetylation and upregulated expression of neurotrophic and neuroprotective factors, resulting in dopaminergic nigrostriatal neuroprotection and reduction of morphological changes and motor behavioural deficits detected through magnetic resonance imaging and behavioural testing respectively. Taken together the data herein provide compelling evidence to support the concept that dependent on isoform specificity, HDACIs represent a novel class of neuroprotective therapeutics for the treatment of PD.Open Acces

Radio-Optical Galaxy Shape and Shear Correlations in the COSMOS Field using 3 GHz VLA Observations

We present a weak lensing analysis of the 3 GHz VLA radio survey of the COSMOS field, which we correlate with overlapping HST-ACS optical observations using both intrinsic galaxy shape and cosmic shear correlation statistics. After cross-matching sources between the two catalogues, we measure the correlations of galaxy position angles and find a Pearson correlation coefficient of $0.14 \pm 0.03$. This is a marked improvement from previous studies which found very weak, or non-existent correlations, and gives insight into the emission processes of radio and optical galaxies. We also extract power spectra of averaged galaxy ellipticities (the primary observable for cosmic shear) from the two catalogues, and produce optical-optical, radio-optical and radio-radio spectra. The optical-optical auto-power spectrum was measured to a detection significance of 9.80$\sigma$ and is consistent with previous observations of the same field. For radio spectra (which we do not calibrate, given the unknown nature of their systematics), although we do not detect significant radio-optical (1.50$\sigma$) or radio-radio (1.45$\sigma$) $E$-mode power spectra, we do find the $E$-mode spectra to be more consistent with the shear signal expected from previous studies than with a null signal, and vice versa for $B$-mode and $EB$ cross-correlation spectra. Our results give promise that future radio weak lensing surveys with larger source number densities over larger areas will have the capability to measure significant weak lensing signals.Comment: 19 pages, 17 figures, accepted for publication in MNRA

Stochastic noise and synchronisation during Dictyostelium aggregation make cAMP oscillations robust

The molecular network, which underlies the oscillations in the concentration of adenosine 3′, 5′-cyclic monophosphate (cAMP) during the aggregation phase of starvation-induced development in Dictyostelium discoideum, achieves remarkable levels of robust performance in the face of environmental variations and cellular heterogeneity. However, the reasons for this robustness remain poorly understood. Tools and concepts from the field of control engineering provide powerful methods for uncovering the mechanisms underlying the robustness of these types of biological systems. Using such methods, two important factors contributing to the robustness of cAMP oscillations in Dictyostelium are revealed. First, stochastic fluctuations in the molecular interactions of the intracellular network, arising from random or directional noise and biological sources, play an important role in preserving stable oscillations in the face of variations in the kinetics of the network. Second, synchronisation of the aggregating cells through the diffusion of extracellular cAMP appears to be a key factor in ensuring robustness to cell-to-cell variations of the oscillatory waves of cAMP observed in Dictyostelium cell cultures. The conclusions have important general implications for the robustness of oscillating biomolecular networks (whether seen at organism, cell, or intracellular levels and including circadian clocks or Ca2+ oscillations, etc.), and suggest that such analysis can be conducted more reliably by using models including stochastic simulations, even in the case where molecular concentrations are very high