We report on the design and first results from experiments looking at the formation of radiative shocks on the Shenguang-II (SG-II) laser at the Shanghai Institute of Optics and Fine Mechanics in China. Laser-heating of a two-layer CH/CH–Br foil drives a $\sim 40$ km/s shock inside a gas cell filled with argon at an initial pressure of 1 bar. The use of gas-cell targets with large (several millimetres) lateral and axial extent allows the shock to propagate freely without any wall interactions, and permits a large field of view to image single and colliding counter-propagating shocks with time-resolved, point-projection X-ray backlighting ($\sim 20$ μm source size, 4.3 keV photon energy). Single shocks were imaged up to 100 ns after the onset of the laser drive, allowing to probe the growth of spatial nonuniformities in the shock apex. These results are compared with experiments looking at counter-propagating shocks, showing a symmetric drive that leads to a collision and stagnation from $\sim 40$ ns onward. We present a preliminary comparison with numerical simulations with the radiation hydrodynamics code ARWEN, which provides expected plasma parameters for the design of future experiments in this facility.

Near infrared (NIR) optical imaging has demonstrated significant potential as an effective modality for cancer molecular imaging. Among various NIR probes currently under investigation, upconversion nanophosphors (UCNPs) possess great promise due to their anti-Stokes emission and sequential photon absorption which result in superior detection sensitivity and a simple imaging setup, respectively. Here we investigated the utility of this imaging modality to detect tumor cells expressing the epidermal growth factor receptor (EGFR) using affibody functionalized nanophosphors and a custom built imaging system. Initially, aqueous dispersible NaYF4: Tm+3, Yb+3 UCNPs were synthesized and their photophysical properties were characterized. Then, their luminescence response as a function of concentration and their depth resolving capability in a tissue-simulating phantom were examined. Finally, we demonstrated the use of bioconjugated UCNPs for imaging EGFR-expressing tumors both in vitro and in vivo. Our data suggests that NIR imaging with UCNPs may be useful for noninvasive imaging of tumors.

The Cu0.8Mg1.2Si2O6 pyroxene has been synthesized using a soft chemistry method. Its crystal structure was determined from powder X-ray diffraction data. Cu0.8Mg1.2Si2O6 crystallizes with the lowclinopyroxene monoclinic structure (space group P21/c). The role of the Jahn-Teller-distorted Cu2+ cation on the stability of this strongly distorted structure is investigated. Cu2+ shows a strong preference for the M2 site, attributed to a better adaptation of its JT-distorted coordination polyhedron to this already distorted and more flexible site. Comparison with previously reported compounds indicates that increasing the Cu content enhances the M2 site distortion, eventually leading to symmetry lowering from orthorhombic Pbca to monoclinic P21/c. These observations bring new insight into the mechanisms of formation and chemical composition of pyroxene minerals in the presence of JT cations.

The central question which this article attempts to raise is how we should understand the social structure that is emerging from the neo-colonial pattern of change in Africa, and what implications it has for politics. In its simplest form, the question is how far a stratification system is developing which is likely to make for class formation, class consciousness, and a politics of class struggle; or how far stratification can be contained within a predominantly peasant society, expressed politically in patron-client relationships.

This paper sets out to consider two related questions: the significance of elections in single-party systems in underdeveloped countries, and the kind of study which political scientists have made of such elections.1

The systematic investigation of corruption is overdue. There are three main types of literature in English on the subject: historical studies of corrupt practice in Britain; inquisitional studies, mainly of the U.S.A. and the English-speaking West African and Asian countries; and sociological studies which deal with corruption incidentally. So far as I know no general study in English has appeared.1 One reason for this seems to be a widespread feeling that the facts cannot be discovered, or that if they can, they cannot be proved, or that if they can be proved, the proof cannot be published. All these notions seem dubious. There are nearly always sources of information, some of them—such as court records—systematic in their way, and some of them very circumstantial (like privileged parliamentary debates). Many of the people involved are quite willing to talk. And commissions of enquiry have published large amounts of evidence, obtained by unusual powers of compulsion.

These conferences grew out of the new University's desire to offer more direct assistance for the development of East Africa. The objects were:

(1) to provide a forum for political leaders from all the East African countries and from some others, in which they could discuss matters of major public policy in an objective and private atmosphere;

(2) to provide a series of opportunities for these leaders to meet and gain a deeper understanding of each other; and

(3) to help establish the fact that the University of East Africa is anxious and able to be of use in facing practical problems.