3-quasi-Sasakian manifolds

In the present paper we carry on a systematic study of 3-quasi-Sasakian manifolds. In particular we prove that the three Reeb vector fields generate an involutive distribution determining a canonical totally geodesic and Riemannian foliation. Locally, the leaves of this foliation turn out to be Lie groups: either the orthogonal group or an abelian one. We show that 3-quasi-Sasakian manifolds have a well-defined rank, obtaining a rank-based classification. Furthermore, we prove a splitting theorem for these manifolds assuming the integrability of one of the almost product structures. Finally, we show that the vertical distribution is a minimum of the corrected energy.Comment: 17 pages, minor modifications, references update

O julgamento das células-tronco : ponderando contra a Constituição

Este artigo aborda a temática de um dos julgamentos mais polêmicos da história do Supremo Tribunal Federal, ocorrido no dia 29 de maio de 2008: por seis votos a cinco, a Lei nº 11.105/2005 (Lei da Biossegurança) foi considerada constitucional. Com essa decisão, foram permitidas as pesquisas com utilização de células-tronco, na forma definida no texto da lei. Todo o julgamento foi acompanhado pela imprensa e por vários setores da sociedade. Os votos proferidos pelos ministros foram submetidos ao debate público e questões ligadas à liberdade de crença e ao direito à vida foram trazidas à superfície

Podcast Interview with Blair Fix on Capitalism, Hierarchy, and Energy

We talk to Blair Fix, a graduate student at York University in Canada, about his fascinating research examining energy and hierarchy and the relationship between hierarchy and personal income. Duration: 1 hour and 25 minute

Suppressive Therapy In The Control Of Bilharziasis: A Comparative Trial In African School Children

A CAJM article on the control of bilharzia-sis in Zimbabwean (Rhodesian) African children.One of the major problems facing the health service in any country which has a high prevalence of bilharziasis is the shortage of medical personnel required for the successful treatment of the large numbers of people who show infection. However, if a totally safe regime involving the administration of relatively innocuous drug at low dosages over long periods of time to control or suppress the level of infection in the person, the administration of the drug could then be left to the teachers or to other responsible members of the community. It is in this context that the policy of suppressive therapy or management of schistosome infections shows its greatest attraction

(A)Political Constituency Development Funds: Evidence from Pakistan

Most of the distributive politics literature focuses on how incumbent politicians allocate development resources in the absence of spending rules, and on the politicization of rules when they do determine distribution. What is less clear is whether politically neutral spending rules lead to neutral spending. Using new data on a long-running federal development fund and elections from Pakistan in a regression discontinuity design, the author presents strong evidence that the ruling party manipulated fund distribution to disproportionately benefit its co-partisans and punish the weakest opposition. Considering various factors, partisan bias is the most plausible explanation. These findings are important not only because the purpose of rules-based funds is to prevent politicized distribution but also because they have implications for development patterns and for using such funds to address questions about legislator effort and patronage patterns within constituencies, which requires assuming that legislators do receive their share of funds in the first place

The First VLBI Image of the Young, Oxygen-Rich Supernova Remnant in NGC 4449

We report on sensitive 1.4-GHz VLBI radio observations of the unusually luminous supernova remnant SNR 4449-1 in the galaxy NGC 4449, which gave us the first well-resolved image of this object. The remnant's radio morphology consists of two approximately parallel bright ridges, suggesting similarities to the barrel shape seen for many older Galactic supernova remnants or possibly to SN 1987A. The angular extent of the remnant is 65 x 40 mas, corresponding to (3.7 x 2.3) x 10^{18} (D/3.8 Mpc) cm. We also present a new, high signal-to-noise optical spectrum. By comparing the remnant's linear size to the maximum velocities measured from optical lines, as well as using constraints from historical images, we conclude that the supernova explosion occurred between ~1905 and 1961, likely around 1940. The age of the remnant is therefore likely ~70 yr. We find that SNR 4449-1's shock wave is likely still interacting with the circumstellar rather than interstellar medium.Comment: 7 pages, Accepted for publication in MNRA

The risk of Cerebral Palsy in survivors of multiple pregnancies with co-fetal loss or death

Objective. This study investigated the risks for cerebral palsy in survivors of multiple pregnancies with cofetal loss (< 20 weeks gestation) or cofetal death. Study Design. The total Western Australian population-based case-control study included 741 cases of cerebral palsy. Results. Antenatal cofetal loss or death occurred in 3% of all cases of cerebral palsy, which is a small but significant contribution. The odds ratio for cerebral palsy in survivors of cofetal loss that included iatrogenic pregnancy reduction was 2.65 (95% confidence interval [CI], 0.78-8.98), which gave a population-attributable proportion of 7.28% (95% CI, 0-27.5), compared with 4.25 (95% CI, 1.12-16.10) and 10.6% (95% CI, 1.0-35.6) for survivors of cofetal death. Conclusion. This study quantifies the contribution of cofetal death to cerebral palsy and suggests that cofetal loss makes a similar, although somewhat smaller, contribution to the risk for cerebral palsy in survivors of multiple pregnancies

Tracheal intubation without neuromuscular blocking drugs in children

No abstract available

Towards Generic Scalable Parallel Combinatorial Search

Combinatorial search problems in mathematics, e.g. in finite geometry, are notoriously hard; a state-of-the-art backtracking search algorithm can easily take months to solve a single problem. There is clearly demand for parallel combinatorial search algorithms scaling to hundreds of cores and beyond. However, backtracking combinatorial searches are challenging to parallelise due to their sensitivity to search order and due to the their irregularly shaped search trees. Moreover, scaling parallel search to hundreds of cores generally requires highly specialist parallel programming expertise. This paper proposes a generic scalable framework for solving hard combinatorial problems. Key elements are distributed memory task parallelism (to achieve scale), work stealing (to cope with irregularity), and generic algorithmic skeletons for combinatorial search (to reduce the parallelism expertise required). We outline two implementations: a mature Haskell Tree Search Library (HTSL) based around algorithmic skeletons and a prototype C++ Tree Search Library (CTSL) that uses hand coded applications. Experiments on maximum clique problems and on a problem in finite geometry, the search for spreads in H(4,2^2), show that (1) CTSL consistently outperforms HTSL on sequential runs, and (2) both libraries scale to 200 cores, e.g. speeding up spreads search by a factor of 81 (HTSL) and 60 (CTSL), respectively. This demonstrates the potential of our generic framework for scaling parallel combinatorial search to large distributed memory platforms