Project Hummingbird: Recovery of a Rocket Using Autorotation

Project Hummingbird is an undergraduate research project with the goal of launching and recovering a sounding rocket using a rotor-recovery system that will safely guide the rocket to landing. It aims to demonstrate an alternative approach to current methods of booster recovery that would, like the other techniques, reduce the cost per launch, but would also require a less complex system and far less fuel. The system is designed to launch with an internally stored rotor-hub and externally folded rotor-blades. At apogee, the rocket will orient itself nose up and deploy the rotor blades. The rotor-blades will auto-rotate and slow the rocket’s descent. An onboard flight computer will control the guidance and descent of the rocket to the ground. Proving such a system involves a series of small-scale model tests to gain an understanding of rotor-blades’ ability to produce lift in unpowered flight. Project members are currently constructing a small-scale model for drop testing in order to gain an understanding of auto-rotational performance at varying speeds and pitch angles, as well as a full-scale rocket for validating all planned and emergency deployment systems. Once the small scale testing is complete and the full-scale rocket has been proven out, conditions for the full-scale autorotation will be selected and full scale tests will be performed. Upon successful landing using autorotation, guidance systems will be developed. The project aims to perform a demonstration flight at the 2019 Spaceport America Cup

Stem-Skilled Parents and Autism Spectrum Disorder in Offspring: A Case-Control Study

Autism spectrum disorder (ASD) is a neurodevelopment disorder characterised by a range of deficits in two specific domains: social communication and social interaction and repetitive patterns of behaviour. Several studies have explored the link between ASD and STEM (science, technology, engineering and mathematics, or other mathematics-grounded disciplines), but results are still uncertain. Objective of the study was to estimate the potential role of systemising abilities in parents as a risk factor for ASD in the offspring, using the achievement of a degree in STEM disciplines as a proxy characteristic of the exposure. There were 1,316 participants overall. There were 658 incident consecutive cases of definite ASD, diagnosed in a Reference Centre for ASD in Italy, from 2001 to 2020. The main exposure variable was parental education level. The risk of ASD in the offspring associated with the main exposure variable and the exposure covariates (e.g. use of neurotropic drugs during the first trimester of the mother’s pregnancy, perinatal outcomes of participants and/or preterm birth) was studied by using conditional logistic regression analysis. In addition, we carried out a mediation analysis to investigate whether and the extent to which covariates significantly associated with ASD risk mediate the relationship between parental education level and ASD in offspring. A STEM degree in parents was significantly associated with risk of ASD in offspring (OR 1.43, 95% CI 1.03-2.54). Familiarity was weakly associated with the risk of ASD (OR 1.33, 95% CI 1.00-1.66) and is the stronger mediator (PME 28%). Sensitivity analysis did not show deviations related to gender or ASD level. Our study moves in the direction of confirming the risk of occurrence of ASD in the offspring of parents with elevated systemising abilities

Du sang et des femmes. Histoire médicale de la menstruation à la Belle Époque

Depuis longtemps, les médecins se sont intéressés au phénomène de la menstruation, qui renvoie au mystère de l’» éternel féminin ». À la fin du XIXe siècle, le discours médical sur les règles recoupe encore sur bien des points les préjugés populaires, notamment en ce qui concerne l’impureté du sang menstruel. Les médecins toutefois ne sont pas unanimes : perçue par certains comme un garant de l’équilibre féminin, une « saignée naturelle » indispensable à la bonne santé de la femme, la menstruation est stigmatisée par d’autres comme un état pathologique induisant chez la femme indisposée des troubles aussi bien physiologiques que psychologiques. La question des règles est ainsi révélatrice d’a priori qui sont tout autant masculins que médicaux, et le discours des médecins ne fait qu’apporter une caution qui se veut scientifique à la perception de la femme comme une éternelle malade, étroitement soumise à son destin biologique.Physicians have long been interested in menstruation, which bears a tight relation to the mystery of femininity itself. At the end of the XIXth century, physicians were as prejudiced as the rest of the population as far as periods were concerned : they thought for instance that menstrual blood was impure. Physicians however were not unanimous. For some of them, menstruation was essential to the equilibrium of women. For others on the contrary, monthly periods were a time of physical and mental disorders. This opinion reveals the deepness of the prejudice against women : physicians just gave a so-called scientific backing to what was commonly thought, i.e. that women were ill creatures, tightly submissive to their biological fate

MR imaging of the metacarpophalangeal joints of the fingers: evaluation of 38 patients with chronic joint disability

Objective: To report the MR imaging findings of painful injured metacarpophalangeal (MCP) joints of the fingers. Design and patients: MR imaging of 39 injured MCP joints in 38 patients was performed after a mean delay of 8.8months. The MR images were obtained with the fingers in extended and flexed positions using T2-weighted and T1-weighted sequences before and after intravenous injection of a gadolinium compound. Ten patients were treated surgically. Mean clinical follow-up was 1.8years. Results: Tears of the collateral ligaments were the most common lesion (30/39), most being radial in location. Contrast-enhanced axial T1-weighted images with the MCP joint in a flexed position showed these lesions optimally. Ten tears were partial and 20 were complete. In 13 patients, MR images showed 17 associated lesions including injuries of the extensor hood (10/17), interosseous tendon (3/17), palmar plate (3/17), and an osteochondral lesion (1/17). Sagittal MR images were essential to highlight palmar plate tears. Conclusion: Partial or complete tears of the collateral ligaments are prevalent MR imaging findings in patients with chronic disability resulting from injuries to the MCP joints. Although conservative treatment generally is sufficient for isolated injuries of the collateral ligaments, surgical repair is often required in cases of more extensive injuries. MR imaging may clearly delineate associated lesions of and about the MCP joint

Formation and destruction of polycyclic aromatic hydrocarbon clusters in the interstellar medium

The competition between the formation and destruction of coronene clusters under interstellar conditions is investigated theoretically. The unimolecular nucleation of neutral clusters is simulated with an atomic model combining an explicit classical force field and a quantum tight-binding approach. Evaporation rates are calculated in the framework of the phase space theory and are inserted in an infrared emission model and compared with the growth rate constants. It is found that, in interstellar conditions, most collisions lead to cluster growth. The time evolution of small clusters (containing up to 312 carbon atoms) was specifically investigated under the physical conditions of the northern photodissociation region of NGC 7023. These clusters are found to be thermally photoevaporated much faster than they are reformed, thus providing an interpretation for the lowest limit of the interstellar cluster size distribution inferred from observations. The effects of ionizing the clusters and density heterogeneities are also considered. Based on our results, the possibility that PAH clusters could be formed in PDRs is critically discussed.Comment: 14 pages, 14 figures. Astronomy & Astrophysics, accepted for publicatio

PESSTO monitoring of SN 2012hn: further heterogeneity among faint type I supernovae

We present optical and infrared monitoring data of SN 2012hn collected by the Public ESO Spectroscopic Survey for Transient Objects (PESSTO). We show that SN 2012hn has a faint peak magnitude (MR ~ -15.7) and shows no hydrogen and no clear evidence for helium in its spectral evolution. Instead, we detect prominent Ca II lines at all epochs, which relates this transient to previously described 'Ca-rich' or 'gap' transients. However, the photospheric spectra (from -3 to +32 d with respect to peak) of SN 2012hn show a series of absorption lines which are unique, and a red continuum that is likely intrinsic rather than due to extinction. Lines of Ti II and Cr II are visible. This may be a temperature effect, which could also explain the red photospheric colour. A nebular spectrum at +150d shows prominent CaII, OI, CI and possibly MgI lines which appear similar in strength to those displayed by core-collapse SNe. To add to the puzzle, SN 2012hn is located at a projected distance of 6 kpc from an E/S0 host and is not close to any obvious starforming region. Overall SN 2012hn resembles a group of faint H-poor SNe that have been discovered recently and for which a convincing and consistent physical explanation is still missing. They all appear to explode preferentially in remote locations offset from a massive host galaxy with deep limits on any dwarf host galaxies, favouring old progenitor systems. SN 2012hn adds heterogeneity to this sample of objects. We discuss potential explosion channels including He-shell detonations and double detonations of white dwarfs as well as peculiar core-collapse SNe.Comment: 14 pages, 14 figures, accepted to MNRAS on 14/10/201

The supernova CSS121015:004244+132827: a clue for understanding super-luminous supernovae

We present optical photometry and spectra of the super luminous type II/IIn supernova CSS121015:004244+132827 (z=0.2868) spanning epochs from -30 days (rest frame) to more than 200 days after maximum. CSS121015 is one of the more luminous supernova ever found and one of the best observed. The photometric evolution is characterized by a relatively fast rise to maximum (~40 days in the SN rest frame), and by a linear post-maximum decline. The light curve shows no sign of a break to an exponential tail. A broad Halpha is first detected at ~ +40 days (rest-frame). Narrow, barely-resolved Balmer and [O III] 5007 A lines, with decreasing strength, are visible along the entire spectral evolution. The spectra are very similar to other super luminous supernovae (SLSNe) with hydrogen in their spectrum, and also to SN 2005gj, sometimes considered a type Ia interacting with H-rich CSM. The spectra are also similar to a subsample of H-deficient SLSNe. We propose that the properties of CSS121015 are consistent with the interaction of the ejecta with a massive, extended, opaque shell, lost by the progenitor decades before the final explosion, although a magnetar powered model cannot be excluded. Based on the similarity of CSS121015 with other SLSNe (with and without H), we suggest that the shocked-shell scenario should be seriously considered as a plausible model for both types of SLSN.Comment: 17 pages, 10 figures and 5 tables. In press to MNRAS. This version matches the accepted one. Main conclusions are unchange

TREND towards more energy-efficient optical networks

International audienceWith one third of the world population online in 2013 and an international Internet bandwidth multiplied by more than eight since 2006, the ICT sector is a non-negligible contributor of worldwide greenhouse gases emissions and power consumption. Indeed, power consumption of telecommunication networks has become a major concern for all the actors of the domain, and efforts are made to reduce their impact on the overall figure of ICTs, and to support its foreseen growth in a sustainable way. In this context, the contributors of the European Network of Excellence TREND have developed innovative solutions to improve the energy efficiency of networks. This paper gives an overview of the solutions related to optical networks

Exploring the social cognition network in young adults with autism spectrum disorder using graph analysis

Background: Autism spectrum disorder (ASD) is characterized by an impairment in social cognition (SC). SC is a cognitive construct that refers to the capacity to process information about social situations. It is a complex network that includes distinct components. Exploring how SC components work together leads to a better understanding of how their interactions promote adequate social functioning. Our main goal was to use a novel statistical method, graph theory, to analyze SC relationships in ASD and Typically Developing (TD) individuals. Methods: We applied graph theory to SC measures to verify how the SC components interact and to establish which of them are important within the interacting SC network for TD and ASD groups. Results: The results showed that, in the TD group, the SC nodes are connected; their network showed increased betweenness among nodes, especially for the Theory of Mind. By contrast, in the SC network in the ASD group the nodes are highly disconnected, and the efficient connection among the components is absent. Conclusion: ASD adults do not show SC competencies and functional communication among these skills. Under this regard, specific components are crucial, suggesting they could represent critical domains for ASD SC