Observations of hydrogen and helium isotopes in solar cosmic rays

The isotopic composition of hydrogen and helium in solar cosmic rays provides a means of studying solar flare particle acceleration mechanisms since the enhanced relative abundance of rare isotopes, such as ²H, ³H and ³He, is due to their production by inelastic nuclear collisions in the solar atmosphere during the flare. In this work the Caltech Electron/Isotope Spectrometer on the IMP-7 spacecraft has been used to measure this isotopic composition. The response of the dE/dx-E particle telescope is discussed and alpha particle channeling in thin detectors is identified as an important background source affecting measurement of low values of (³He/⁴He).

The following flare-averaged results are obtained for the period, October, 1972 - November, 1973: (²H/¹H) = 7⁺¹⁰_-6 X 10^-6 (1.6 - 8.6 MeV/nuc), (³H/¹H) less than 3.4 x 10^-6 (1.2 - 6.8 MeV/nuc), (³He/⁴He) = (9 ± 4) x 10^-3, (³He/¹H) = (1.7 ± 0.7) x 10^-4 (3.1 - 15.0 MeV/nuc). The deuterium and tritium ratios are significantly lower than the same ratios at higher energies, suggesting that the deuterium and tritium spectra are harder than that of the protons. They are, however, consistent with the same thin target model relativistic path length of ~ 1 g/cm² (or equivalently ~ 0.3 g/cm² at 30 MeV/nuc) which is implied by the higher energy results. The ³He results, consistent with previous observations, would imply a path length at least 3 times as long, but the observations may be contaminated by small ³He rich solar events.

During 1973 three "³He rich events," containing much more ³He than ²H or ³H were observed on 14 February, 29 June and 5 September. Although the total production cross sections for ²H,³H and ³He are comparable, an upper limit to (²H/³He) and (³H/³He) was 0.053 (2.9-6.8 MeV/nuc), summing over the three events. This upper limit is marginally consistent with Ramaty and Kozlovsky's thick target model which accounts for such events by the nuclear reaction kinematics and directional properties of the flare acceleration process. The 5 September event was particularly significant in that much more ³He was observed than ⁴He and the fluxes of ³He and ¹H were about equal. The range of (³He/⁴He) for such events reported to date is 0.2 to ~ 6 while (³He/¹H) extends from 10^-3 to ~ 1. The role of backscattered and mirroring protons and alphas in accounting for such variations is discussed.

Studies of response to earthquake ground motion

A study is made of the accuracy of electronic digital computer calculations of ground displacement and response spectra from strong-motion earthquake accelerograms. This involves an investigation of methods of the preparatory reduction of accelerograms into a form useful for the digital computation and of the accuracy of subsequent digital calculations. Various checks are made for both the ground displacement and response spectra results, and it is concluded that the main errors are those involved in digitizing the original record. Differences resulting from various investigators digitizing the same experimental record may become as large as 100% of the maximum computed ground displacements. The spread of the results of ground displacement calculations is greater than that of the response spectra calculations. Standardized methods of adjustment and calculation are recommended, to minimize such errors.

Studies are made of the spread of response spectral values about their mean. The distribution is investigated experimentally by Monte Carlo techniques using an electric analog system with white noise excitation, and histograms are presented indicating the dependence of the distribution on the damping and period of the structure. Approximate distributions are obtained analytically by confirming and extending existing results with accurate digital computer calculations. A comparison of the experimental and analytical approaches indicates good agreement for low damping values where the approximations are valid. A family of distribution curves to be used in conjunction with existing average spectra is presented. The combination of analog and digital computations used with Monte Carlo techniques is a promising approach to the statistical problems of earthquake engineering.

Methods of analysis of very small earthquake ground motion records obtained simultaneously at different sites are discussed. The advantages of Fourier spectrum analysis for certain types of studies and methods of calculation of Fourier spectra are presented. The digitizing and analysis of several earthquake records is described and checks are made of the dependence of results on digitizing procedure, earthquake duration and integration step length. Possible dangers of a direct ratio comparison of Fourier spectra curves are pointed out and the necessity for some type of smoothing procedure before comparison is established. A standard method of analysis for the study of comparative ground motion at different sites is recommended.

Entrainment of fine sediments by turbulent flows

A study was made of the means by which turbulent flows entrain sediment grains from alluvial stream beds. Entrainment was considered to include both the initiation of sediment motion and the suspension of grains by the flow. Observations of grain motion induced by turbulent flows led to the formulation of an entrainment hypothesis. It was based on the concept of turbulent eddies disrupting the viscous sublayer and impinging directly onto the grain surface. It is suggested that entrainment results from the interaction between fluid elements within an eddy and the sediment grains.

A pulsating jet was used to simulate the flow conditions in a turbulent boundary layer. Evidence is presented to establish the validity of this representation. Experiments were made to determine the dependence of jet strength, defined below, upon sediment and fluid properties. For a given sediment and fluid, and fixed jet geometry there were two critical values of jet strength: one at which grains started to roll across the bed, and one at which grains were projected up from the bed. The jet strength K, is a function of the pulse frequency, ω, and the pulse amplitude, A, defined by

K = Aω^-s

Where s is the slope of a plot of log A against log ω. Pulse amplitude is equal to the volume of fluid ejected at each pulse divided by the cross sectional area of the jet tube.

Dimensional analysis was used to determine the parameters by which the data from the experiments could be correlated. Based on this, a method was devised for computing the pulse amplitude and frequency necessary either to move or project grains from the bed for any specified fluid and sediment combination.

Experiments made in a laboratory flume with a turbulent flow over a sediment bed are described. Dye injection was used to show the presence, in a turbulent boundary layer, of two important aspects of the pulsating jet model and the impinging eddy hypothesis. These were the intermittent nature of the sublayer and the presence of velocities with vertical components adjacent to the sediment bed.

A discussion of flow conditions, and the resultant grain motion, that occurred over sediment beds of different form is given. The observed effects of the sediment and fluid interaction are explained, in each case, in terms of the entrainment hypothesis.

The study does not suggest that the proposed entrainment mechanism is the only one by which grains can be entrained. However, in the writer’s opinion, the evidence presented strongly suggests that the impingement of turbulent eddies onto a sediment bed plays a dominant role in the process.

Delivery of Targeted Nanoparticles Across the Blood-Brain Barrier Using a Detachable Targeting Ligand

Chronic diseases of the central nervous system are poorly treated due to the inability of most therapeutics to cross the blood-brain barrier. The blood-brain barrier is an anatomical and physiological barrier that severely restricts solute influx, including most drugs, from the blood to the brain. One promising method to overcome this obstacle is to use endogenous solute influx systems at the blood-brain barrier to transport drugs. Therapeutics designed to enter the brain through transcytosis by binding the transferrin receptor, however, are restricted within endothelial cells. The focus of this work was to develop a method to increase uptake of transferrin-containing nanoparticles into the brain by overcoming these restrictive processes.

To accomplish this goal, nanoparticles were prepared with surface transferrin molecules bound through various liable chemical bonds. These nanoparticles were designed to shed the targeting molecule during transcytosis to allow increased accumulation of nanoparticles within the brain.

Transferrin was added to the surface of nanoparticles through either redox or pH sensitive chemistry. First, nanoparticles with transferrin bound through disulfide bonds were prepared. These nanoparticles showed decreased avidity for the transferrin receptor after exposure to reducing agents and increased ability to enter the brain in vivo compared to those lacking the disulfide link.

Next, transferrin was attached through a chemical bond that cleaves at mildly acidic pH. Nanoparticles containing a cleavable link between transferrin and gold nanoparticle cores were found to both cross an in vitro model of the blood-brain barrier and accumulate within the brain in significantly higher numbers than similar nanoparticles lacking the cleavable bond. Also, this increased accumulation was not seen when using this same strategy with an antibody to transferrin receptor, indicating that behavior of nanoparticles at the blood-brain barrier varies depending on what type of targeting ligand is used.

Finally, polymeric nanoparticles loaded with dopamine and utilizing a superior acid-cleavable targeting chemistry were investigated as a potential treatment for Parkinson’s disease. These nanoparticles were capable of increasing dopamine quantities in the brains of healthy mice, highlighting the therapeutic potential of this design. Overall, this work describes a novel method to increase targeted nanoparticle accumulation in the brain.

Significados corporificados: uma análise da definição de arte de Arthur C. Danto

O objetivo do presente trabalho é analisar a resposta de Danto ao problema da natureza da arte. Para isso, investigaremos o modo como ele utiliza os experimentos dos indiscerníveis, tanto para objetar as teorias tradicionais da arte como para erigir sua definição; e filosofia da arte, o que pode ser chamado, respectivamente, de tarefa negativa e tarefa positiva do uso do método dos indiscerníveis. A primeira parte desse trabalho se ocupa da tarefa de investigar justamente como os experimentos dos indiscerníveis são usados para objetar as teorias mimética, formalista, expressivista, institucionais, da atitude estética, e, por fim, a teoria da indefinibilidade da arte. A segunda parte trata de demonstrar como Danto, através dos experimentos dos indiscerníveis, extrai as condições necessárias e suficientes de sua definição de arte. A terceira e última parte deste trabalho analisa a relação existente entre a definição da arte e a filosofia da história da arte de Danto, principalmente a tese acerca do fim da arte.

Ludwig Feuerbach's Critique of Religion and the End of Moral Philosophy

Williams, H. (2006). Ludwig Feuerbach's Critique of Religion and the End of Moral Philosophy. In Moggach, D. (Ed.), The New Hegelians: Politics and Philosophy in the Hegelian School (pp.50-66). Cambridge: Cambridge University Press. Introduction; Part I. Eduard Gans: 1. Eduard Gans on poverty and on the constitutional debate; 2. Ludwig Feuerbach's Critique of Religion and the end of moral philosophy; Part II. Ludwig Feuerbach: 3. The symbolic dimension and the politics of Left Hegelianism; Part III. Bruno Bauer: 4. Exclusiveness and political universalism in Bruno Bauer; 5. Republican rigorism and emancipation in Bruno Bauer; Part IV. Edgar Bauer: 6. Edgar Bauer and The Origins of the Theory of Terrorism; Max Stirner 7. Ein Menschenleben: Hegel and Stirner; 8. 'The State and I': Max Stirner's anarchism; Friedrich Engels: 9. Engels and the invention of the catastrophist conception of the industrial revolution; Karl Marx: 10. The basis of the state in the Marx of 1842; 11. Marx and Feuerbachian essence: returning to the question of 'Human Essence' in historical materialism; 12. Freedom and the 'Realm of Necessity'; Concluding with Hegel :13. Work, language and community: a response to Hegel's critics. RAE2008

People and Politics in France, 1848-1870

Price, Roger, People and Politics in France, 1848-1870 (Cambridge: Cambridge University Press, 2004), pp.x+477 RAE2008

La narrativa indigenista en Argentina. Una doble denuncia

Desde tiempos de José Carlos Mariátegui, la crítica literaria indigenista viene articulando un discurso etnocentrista cuyo eje de producción se sitúa en Perú y los países vecinos, pero rara vez se ha mencionado una obra argentina que trate sobre las desigualdades que sufren los indígenas de ese país. Ni siquiera la academia argentina ha analizado ninguna novela desde la óptica indigenista.En un país cuyos gobiernos, desde el siglo XIX, han tratado de borrar cualquier traza de sangre indígena en su población, ya sea mediante la asimilación, exterminio o invisibilidad, y cuyas zonas de mayor asentamiento indígena se encuentran lejos del hegemónico Buenos Aires, las narraciones de problemas sociales ajenos quedaban encajonadas en el recóndito mundo de la literatura regional.Sin embargo, durante los años de eclosión del movimiento indigenista, escritores argentinos se hicieron eco de los sufrimientos y demandas de sus compatriotas indígenas por medio de novelas que sobrepasaron el peyorativo epíteto regionalista y que incomprensiblemente, han sido olvidadas.En este artículo, que forma parte de un estudio más amplio, se aborda el silencio crítico, se contextualiza la producción indigenista de la época y se analizan brevemente algunas de las obras.

Patrick Moore, Arthur C. Clarke and ‘British Outer Space’ in the mid 20th century

This article seeks to explore a notion of 'British outer space' in the mid 20th century with reference to the British Interplanetary Society and the works of Patrick Moore and Arthur C. Clarke. Geographies of outer space have been examined following early work by Denis Cosgrove on the Apollo space photographs. Cosgrove's work has encouraged a growing body of work that seeks to examine both the 'Earth from space' perspective as well as its reciprocal, 'space from Earth'. This article aligns itself with the latter viewpoint, in attempting to define a national culture of 'British outer space'. This is found to have an important connection with the British Interplanetary Society, founded in 1933 near Liverpool, which went on to influence the works of Patrick Moore, who edited the magazine Spaceflight and presented the television programme The Sky at Night, and Arthur C. Clarke, who became known as a science fiction writer through his early novels in the 1950s. The themes of audience participation and human destiny in outer space are examined in a close reading of these two case studies, and further engagement with cultures of outer space in geography is encouraged. © The Author(s) 2012.

The east of Suez decision

A witness seminar on Britain's decision to withdraw from East of Suez was held by the Institute of Contemporary British History at King's College London on 16 November 1990. It was introduced by a short paper by David Greenwood of the Centre for the Study of Defence Economics, University of Aberdeen. Those participating were Professor Lawrence Freedman (Chairman), David Greenwood, Sir Frank Cooper, C.W. Wright, Sir Patrick Nairne, Richard Hastie‐Smith, J.K. Wright, Sir Ewen Broadbent, Peter Hudson, Sir Robert Andrew, Sir George Leitch, Sir Arthur Drew, Lord Thomson of Monifieth, Lord Zuckerman, Lord Mayhew and Field Marshal Lord Carver. The Institute of Contemporary British History would like to record its thanks to BP for its sponsorship of this event.

Technology transfer in Britain: the case of monoclonal antibodies

In 1975 two Cambridge scientists published a short article in Nature which announced the discovery of monoclonal antibodies. The article concluded ‘Such cultures could be valuable for medical and industrial use’. The interest which developed by the end of the decade in the industrial and financial possibilities of the new prospects opening up in biotechnology was to throw the apparent ‘failure’ to follow‐up the potentialities of this discovery into a public prominence rarely achieved by scientific discoveries. By the time Mrs Thatcher came to power it had become a scandal, another example of Britain's apparent inability to exploit effectively the brilliance of its scientific base. It was to explore both the process of scientific discovery and the conditions in Cambridge which nurtured it, and the issues which this particular discovery raised in the area of technology transfer (and the changes of policy that ensued), that the Wellcome Trust's History of Twentieth Century Medicine Group and the Institute of Contemporary British History organised this special witness seminar. It was held at the Wellcome Trust in London on 24 September 1993. The seminar was chaired by Sir Christopher Booth and introduced by Dr Robert Bud of the Science Museum. Those participating included the two authors of the Nature article, Dr César Milstein and Dr Georges Köhler, who received a Nobel Prize for their research, Dr Basil Bard (National Research Development Corporation [NRDC] 1950–74), Sir James Gowans (Secretary of the Medical Research Council [MRC] 1977–87), Sir John Gray (Secretary of the MRC 1968–77), John Newell (BBC World Service science correspondent 1969–79), Dr David Owen (MRC), and Dr David Secher (Laboratory of Molecular Biology [LMB], Cambridge). There were also contributions from Dr Ita Askonas (former head of immunology at the National Institute for Medical Research), Dr John Galloway (former member of MRC headquarters staff), Dr David Tyrrell (former Director, MRC Common Cold Unit), Professor Miles Weatherall (head of Therapeutic Research Division, Wellcome Research Laboratories 1967–75), Dr Guil Winchester (post‐doctoral fellow, Wellcome Institute for the History of Medicine), and Dr Peter Williams (former Director of the Wellcome Trust). The organisers would like to thank the Wellcome Trust for hosting and sponsoring the seminar. We would like to dedicate this publication to the memory of Georges Köhler, who sadly died in April 1995 before this could appear.

Revue critique d'histoire et de littérature / publiée sous la direction de MM. P. Meyer, Ch. Morel, G. Paris, H. Zotenberg

1930/07/01 (N7,A64,T97)-1930/07/31.

Revue critique d'histoire et de littérature / publiée sous la direction de MM. P. Meyer, Ch. Morel, G. Paris, H. Zotenberg

1930/05/01 (N5,A64,T97)-1930/05/31.

Revue critique d'histoire et de littérature / publiée sous la direction de MM. P. Meyer, Ch. Morel, G. Paris, H. Zotenberg

1930/06/01 (N6,A64,T97)-1930/06/30.