Problems with interpretation of 10^{10}He ground state

The continuum of $^{10}$He nucleus is studied theoretically in a three-body $^{8}$He+$n$+$n$ model basing on the recent information concerning $^9$He spectrum [Golovkov, \textit{et al.}, Phys. Rev. C \textbf{76}, 021605(R) (2007)]. The $^{10}$He ground state (g.s.) candidate with structure $[p_{1/2}]^2$ for new g.s. energy of $^9$He is predicted to be at about $2.0-2.3$ MeV. The peak in the cross section associated with this state may be shifted to a lower energy (e.g. $\sim 1.2$ MeV) when $^{10}$He is populated in reactions with $^{11}$Li due to peculiar reaction mechanism. Formation of the low-energy ($E< 250$ keV) ``alternative'' ground state with structure $[s_{1/2}]^2$ is highly probable in $^{10}$He in the case of considerable attraction (e.g. $a<-5$ fm) in the s-wave $^9$He channel, which properties are still quite uncertain. This result either questions the existing experimental low-energy spectrum of $^{10}$He or place a limit on the scattering length in $^9$He channel, which contradicts existing data.Comment: 14 pages, 13 figures, 1 tabl

The Tuareg: between armed uprising and drought

he recent Tuareg uprising in Mali under the banner of the MNLA has raised concerns over stability and safety in the region, with much attention focussed on the Libya and AQIM (Al Qaeda in the Islamic Maghreb) ‘connections’. The framing of the conflict in terms of international security and political (in)stability elsewhere obscures the causes, considerations and implications on a local level. Here we will try to discuss the conflict from a Tuareg perspective, estimating the impact of local, international and national concerns on the chances for peace or lasting conflict

Lunar igneous intrusions

Lunar igneous intrusions revealed from Apollo 10 and 11 flight photograph

Mali: how bad can it get?

From dusk till late evening, you can find small groups of young people sitting on street corners, in front of houses, or in courtyards across West Africa. There will inevitably be a little radio, playing music and broadcasting news. The ‘junior’ of the group is busy brewing and passing round small glasses of tea, while the others hang out, play cards, and discuss the news they hear, whether it comes from Radio France Internationale or sidewalk radio. In Mali, such a group is called a grin. Below, a virtual grin, a group chat among five researchers discussing the news on Mali, from wherever it comes

A Pragmatic Study of Female and Male Discourse Use on Facebook

La comunicación virtual es un campo de estudio muy interesante e innovador que analiza las distintas estrategias comunicativas empleadas en este tipo de discurso que difieren de las empleadas en la comunicación verbal. Este trabajo empieza revisando investigaciones precedentes en este tema para posteriormente analizar, desde un punto de vista pragmático, las diferencias del uso del discurso femenino y masculino en Facebook, sin caer en una perspectiva sexista. El problema principal en este estudio ha sido intentar establecer dicha comparación. Para poder acometer este estudio, recurrimos primero al análisis descriptivo de un corpus creado con discursos reales sacados de la propia red social, para elaborar un cuestionario Likert de 5 puntos, y poder realizar así un estudio experimental que nos permitiera probar si los marcadores textuales utilizados por hombres y mujeres difieren en sus respectivos discursos. Los resultados revelaron una diferencia estadísticamente significativa entre ambos tipos de discursos al comunicarse en Facebook. Sin embargo, también obtuvimos algunos resultados inesperados en relación al uso de los marcadores discursivos utilizados por el grupo de mujeres jóvenes que eran muy parecidos a los utilizados por los hombres en ambas condiciones, tanto en los jóvenes como en los adultos. Por esta razón, la conclusión es que existen rasgos distintivos en los usos discursivos femeninos y masculinos, aunque en el caso de las mujeres jóvenes su discurso parece estar cambiando, puesto que se asemeja cada vez más al discurso masculino. No obstante, sería necesario llevar a cabo una investigación sobre el cambio discursivo de las mujeres jóvenes para tratar de establecer sus causas.Virtual communication is an interesting and innovative field study which analyses the communicative strategies used in this type of discourse, different from the ones used in face-to-face communication. This work first reviews some previous research on the topic to then analyse from a pragmatic perspective the differences between female and male discoursre uses on Facebook, without succumbing to a sexist perspective. To carry out this analysis, we resorted to a corpus made with real conversations from Facebook to elaborate a 5-pint Likert scale, and so conduct an experimental survey to test whether women and men actually use different discourse markers in their respective discourses. The results revealed that there was a statistically significant distinction in the female and male discourse use when communicating on Facebook. However, some unexpected results were also obtained regarding the discourse markers used by women in the female young adult group condition, which were very similar to those used by men in both the young adult and adult condition. Hence, the conclusion is that there are distinctive features of both female and male discourse use that allow us to identify the two different gender identities, though young women’s discourse use seems to be changing and increasingly resembling to the male discourse. Further research is needed to shed some more light on the change of discourse use found in young women to try to determine its causes.31 páginas y anex

A comparison between IMSC, PI and MIMSC methods in controlling the vibration of flexible systems

A comparative study is presented between three active control algorithms which have proven to be successful in controlling the vibrations of large flexible systems. These algorithms are: the Independent Modal Space Control (IMSC), the Pseudo-inverse (PI), and the Modified Independent Modal Space Control (MIMSC). Emphasis is placed on demonstrating the effectiveness of the MIMSC method in controlling the vibration of large systems with small number of actuators by using an efficient time sharing strategy. Such a strategy favors the MIMSC over the IMSC method, which requires a large number of actuators to control equal number of modes, and also over the PI method which attempts to control large number of modes with smaller number of actuators through the use of an in-exact statistical realization of a modal controller. Numerical examples are presented to illustrate the main features of the three algorithms and the merits of the MIMSC method

Active control of buckling of flexible beams

The feasibility of using the rapidly growing technology of the shape memory alloys actuators in actively controlling the buckling of large flexible structures is investigated. The need for such buckling control systems is becoming inevitable as the design trends of large space structures have resulted in the use of structural members that are long, slender, and very flexible. In addition, as these truss members are subjected mainly to longitudinal loading they become susceptible to structural instabilities due to buckling. Proper control of such instabilities is essential to the effective performance of the structures as stable platforms for communication and observation. Mathematical models are presented that simulate the dynamic characteristics of the shape memory actuator, the compressive structural members, and the associated active control system. A closed-loop computer-controlled system is designed, based on the developed mathematical models, and implemented to control the buckling of simple beams. The performance of the computer-controlled system is evaluated experimentally and compared with the theoretical predictions to validate the developed models. The obtained results emphasize the importance of buckling control and suggest the potential of the shape memory actuators as attractive means for controlling structural deformation in a simple and reliable way

Prisons, pipelines, and pedagogy: Diary of the birth of a behind-bars college program Part 2

The second in a two-part series on beginning a college program for prisoners

Northern Mali: the things we assume

Events have developed quickly these last days and weeks in Mali, as fast as an all terrain vehicle can drive in the sand, basically. And although electronic media can go faster than four wheel drives, they can only go as fast as the rumours they feed on. Elsewhere, I have argued that in following events in the Sahara, everything is shrouded in a haze of dust. Nothing is known with certainty, all depends on rumour and a form of hearsay known as ‘the Tuareg telegraph’ that can only be interpreted with deep inside knowledge of the Saharan world.[1] I shall be honest, I can no longer rightly claim to have that deep inside knowledge, it is too long ago since I was last in the Azawad.[2] But the same goes for the vast majority of journalists and Sahara watchers now active, which leads me to plead here for extreme prudence in the analysis of the current situation in Northern Mali, a prudence that is often ignored in favour of tempting speculations. Here I would like to address a few of these pieces of speculative analysis with the single goal of asking for more prudence because precipitous judgements can have grave consequences for the future denouement of the conflict