Measurement of exclusive γγ→ℓ+ℓ− production in proton--proton collisions at s√=7 TeV with the ATLAS detector

This Letter reports a measurement of the exclusive γγ→ℓ+ℓ−(ℓ=e,μ) cross-section in proton--proton collisions at a centre-of-mass energy of 7 TeV by the ATLAS experiment at the LHC, based on an integrated luminosity of 4.6 fb−1. For the electron or muon pairs satisfying exclusive selection criteria, a fit to the dilepton acoplanarity distribution is used to extract the fiducial cross-sections. The cross-section in the electron channel is determined to be σexcl.γγ→e+e−=0.428±0.035(stat.)±0.018(syst.) pb for a phase-space region with invariant mass of the electron pairs greater than 24 GeV, in which both electrons have transverse momentum pT>12 GeV and pseudorapidity |η|<2.4. For muon pairs with invariant mass greater than 20 GeV, muon transverse momentum pT>10 GeV and pseudorapidity |η|<2.4, the cross-section is determined to be σexcl.γγ→μ+μ−=0.628±0.032(stat.)±0.021(syst.) pb. When proton absorptive effects due to the finite size of the proton are taken into account in the theory calculation, the measured cross-sections are found to be consistent with the theory prediction.

Fresh-water Algae of the United States; (exclusive of the Diatomaceae) complemental to Desmids of the United States ... One hundred and fifty-one plates ... including nine additional plates of desmids. By the Rev. Francis Wolle ...

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British fresh-water algae, exclusive of Desmidieae and Diatomaceae, by M. C. Cooke.

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British fresh-water algae, exclusive of Desmidieae and Diatomaceae, by M. C. Cooke.

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Fresh-water Algae of the United States; (exclusive of the Diatomaceae) complemental to Desmids of the United States ... One hundred and fifty-one plates ... including nine additional plates of desmids. By the Rev. Francis Wolle ...

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Dealing with Tyranny: International Sanctions and Autocrats’ Duration

This paper enquires into whether economic sanctions are effective in destabilizing authoritarian rulers. We argue that this effect is mediated by the type of authoritarian regime against which sanctions are imposed. Thus, personalist regimes and monarchies, which are more dependent on aid and resource rents to maintain their patronage networks, are more likely to be affected by sanctions. In contrast, single-party and military regimes are able to maintain (and even increase) their tax revenues and to reallocate their expenditures and so increase their levels of cooptation. Data on sanction episodes, authoritarian rulers and regimes covering the period 1946–2000 have allowed us to test our hypotheses. To do so, duration models have been run, and the results confirm that personalist autocrats are more vulnerable to foreign pressure. Concretely, the analysis of the modes of exit reveals that sanctions increase the likelihood of an irregular change of ruler, such as a coup. Sanctions are basically ineffective when targeting single-party or military regimes.

Exclusive Nightclubs and Lonely Hearts Columns: Nonmonotone Participation in Optional Intermediation

In many decentralised markets, the traders who benefit most from an exchange do not employ intermediaries even though they could easily afford them. At the same time, employing intermediaries is not worthwhile for traders who benefit little from trade. Together, these decisions amount to non-monotone participation choices in intermediation: only traders of middle “type” employ intermediaries, while the rest, the high and the low types, prefer to search for a trading partner directly. We provide a theoretical foundation for this, hitherto unexplained, phenomenon. We build a dynamic matching model, where a trader’s equilibrium bargaining share is a convex increasing function of her type. We also show that this is indeed a necessary condition for the existence of non-monotone equilibria.

Perspectives de l'inactivation des pathogènes: quand la fiction dépasse la réalité [Back to the future: a fiction dealing with pathogen inactivation of blood products].

AIM OF THE PAPER: Arouse the reflection with a fiction having a scientific appearance, presenting a late and unexpected complication of the universal inactivation of pathogens. CONCLUSION: Such a fiction story opens the debate on a series of fundamental questions that could be addressed during the paradigm shift that is expected by introducing universal pathogen inactivation of blood products.

Photographic art and dealing with death

Recently, we were faced with a request from a student photographer who wanted to take pictures of bodies donated to our institute and used for dissection courses for medical students or for scientific purposes. Students are expressly forbidden to take pictures in the dissection hall; however, we allowed this student photographer to do her diploma work in our institute. The reason why she was proposing such a topic was that her brother died young and her parents donated his body to science. To overcome this loss of a loved one, she wanted to know what happens to the donated bodies. She followed the procedure of embalming and different dissections that took place during the summer semester and she took pictures throughout. The outcome of this work was a very nice photographic document, called 'dissection', a book with many pictures but no figure legends. The image document shows the different steps in the preparation and preservation of bodies and the work of an anatomist in the dissection hall. As we impose rules on our students, we had also to give directives in the use of the photographs taken, especially for a photographer who will use the most prominent pictures for exhibitions, i.e. that the pictures do not show names or are used for publication on the internet, or show identification numbers of cadavers, or give indication ofn the institution and are relatively anonymous. This story tells how one can deal with death and at the same time advance one's personal career. The author represents the Swiss Anatomical Society SGAHE and is supported by the Swiss Academy of Science, ScNat.

Epidemiology and Anthropology: an integrated approach dealing with bio-socio-cultural aspects as strategy for the control of endemic diseases

The control of endemic diseases has not attained the desired level of effectiveness in spite of the use of modern efficient thecnologies. The classic interventionist approach for the control of schistosomiasis is centered on systemic control of the snail hosts combined to large scale medical treatment and is usually carried out without social preocupation due to the assisted communities. It is easy to understand the interest and the ethical compromise of public health research while producing studies in which the biological and social determinants as well as the cultural components should be considered and also encompass the historical dimensions and symbolic representations. In face of the recent political decision in favor of decentralizations of health administration to municipal level, we suggest, in the present paper, an integrated approach for the epidemiological diagnosis of an endemic situation at local level. Theoretical and methodological aspects from both, epidemiology and anthropology are discussed. Epidemiological methods can be used to detect the dependent variables (those related to the human infection) and the independent variables (demographic, economic, sanitary and social). Another methodological approach of anthropological /etnographic nature can be conducted in order to make an articulation of the knowledge on the various dimensions or determinant levels of the disease. Mutual comprehension, between researchers and the people under investigation, on the dynamic transmission process would be relevant for a joint construction, at local level, of programmed actions for the control of endemic diseases. This would extend reflections on the health/disease process as a whole.