L’essor de l’industrie pétrochimique en Arabie Saoudite

Eight giant petrochemical joint ventures will come on stream in Saudi Arabia between 1983 and 1985, reaching full capacity by 1987. While the equity for these complexes will be at least $12 billion, they will benefit from very cheap feedstock making them highly competitive. With the foreign partners in the ventures marketing much of the output abroad and with a growing domestic demand, there should be little difficulty with sales. In any event Saudi Arabia can link the sale of petrochemicals with the availability of crude oil. A re-structuring of the world production of petrochemicals is virtually inevitable, with Saudi Arabia and other countries with cheap feedstock producing bulk petrochemicals while the more industrialized countries concentrate on specialty petrochemicals with a greater value-added. Quebec, with petrochemicals a growth sector, is well placed to take advantage of these changes. Saudi Arabia, which normally runs a substantial trade surpluses with Quebec—some$360 million in 1981—might well opt to invest part of theses surpluses in a petrochemical industry in Quebec

L’essor de l’industrie pétrochimique en Arabie Saoudite

Eight giant petrochemical joint ventures will come on stream in Saudi Arabia between 1983 and 1985, reaching full capacity by 1987. While the equity for these complexes will be at least $12 billion, they will benefit from very cheap feedstock making them highly competitive. With the foreign partners in the ventures marketing much of the output abroad and with a growing domestic demand, there should be little difficulty with sales. In any event Saudi Arabia can link the sale of petrochemicals with the availability of crude oil. A re-structuring of the world production of petrochemicals is virtually inevitable, with Saudi Arabia and other countries with cheap feedstock producing bulk petrochemicals while the more industrialized countries concentrate on specialty petrochemicals with a greater value-added. Quebec, with petrochemicals a growth sector, is well placed to take advantage of these changes. Saudi Arabia, which normally runs a substantial trade surpluses with Quebec—some$360 million in 1981—might well opt to invest part of theses surpluses in a petrochemical industry in Quebec.

Physics of Eclipsing Binaries: Heartbeat Stars and Tidally Induced Pulsations

Heartbeat stars are a relatively new class of eccentric ellipsoidal variable first discovered by Kepler. An overview of the current field is given with details of some of the interesting objects identified in our current Kepler sample of 135 heartbeats stars. Three objects that have recently been or are undergoing detailed study are described along with suggestions for further avenues of research. We conclude by discussing why heartbeat stars are an interesting new tool to study tidally induced pulsations and orbital dynamics

Impact of Rubin Observatory LSST Template Acquisition Strategies on Early Science from the Transients and Variable Stars Science Collaboration: Non-time-critical Science Cases

Vera C. Rubin Observatory Legacy Survey of Space and Time, LSST, will revolutionize modern astronomy by producing an extremely deep (coadded depth ~27 mag) depth-limited survey of the entire southern sky (LSST Science Collaboration et al. 2009). The 8.4 m large-aperture, wide-field telescope, which is based in Cerro Pachón, will image the entire Southern sky every three nights in multiple bands (SDSS-u, g, r, i, z, y) and produce a fire-hose of data, 20 Tb each night, concluding in a 60 petabyte data set as the legacy of the 10 yr survey. Extracting meaningful light curves from variable objects requires difference imaging to both identify variability and calibrate light curve data products. Templates, co-added groups of visits that act as an image of the "static" sky, are a key component of Difference Imaging Analysis (DIA) and as such are of paramount importance for all science that involves variable objects. As the "non-time-critical" science cases discussed here are mostly periodic, they generally do not depend upon the survey alert stream; however, templates are still crucial for performing science and calibrations during the first year. We provide recommendations for observing strategies for template acquisition starting from commissioning and through Year 1 of the survey

Red-giant stars in eccentric binaries

The unparalleled photometric data obtained by NASA’s Kepler Space Telescope has led to improved understanding of red-giant stars and binary stars. We discuss the characterization of known eccentric system, containing a solar-like oscillating red-giant primary component. We also report several new binary systems that are candidates for hosting an oscillating companion. A powerful approach to study binary stars is to combine asteroseimic techniques with light curve fitting. Seismology allows us to deduce the properties of red giants. In addition, by modeling the ellipsoidal modulations we can constrain the parameters of the binary system. An valuable independent source are ground-bases, high-resolution spectrographs

Effect of dead space on avalanche speed

The effects of dead space (the minimum distance travelled by a carrier before acquiring enough energy to impact ionize) on the current impulse response and bandwidth of an avalanche multiplication process are obtained from a numerical model that maintains a constant carrier velocity but allows for a random distribution of impact ionization path lengths. The results show that the main mechanism responsible for the increase in response time with dead space is the increase in the number of carrier groups, which qualitatively describes the length of multiplication chains. When the dead space is negligible, the bandwidth follows the behavior predicted by Emmons but decreases as dead space increase

Signal transducer and activator of transcription 2 deficiency is a novel disorder of mitochondrial fission

Defects of mitochondrial dynamics are emerging causes of neurological disease. In two children presenting with severe neurological deterioration following viral infection we identified a novel homozygous STAT2 mutation, c.1836C4A (p.Cys612Ter), using whole exome sequencing. In muscle and fibroblasts from these patients, and a third unrelated STAT2-deficient patient, we observed extremely elongated mitochondria. Western blot analysis revealed absence of the STAT2 protein and that the mitochondrial fission protein DRP1 (encoded by DNM1L) is inactive, as shown by its phosphorylation state. All three patients harboured 15 decreased levels of DRP1 phosphorylated at serine residue 616 (P-DRP1S616), a post-translational modification known to activate DRP1, and increased levels of DRP1 phosphorylated at serine 637 (P-DRP1S637), associated with the inactive state of the DRP1 GTPase. Knockdown of STAT2 in SHSY5Y cells recapitulated the fission defect, with elongated mitochondria and decreased PDRP1 S616 levels. Furthermore the mitochondrial fission defect in patient fibroblasts was rescued following lentiviral transduction with wild-type STAT2 in all three patients, with normalization of mitochondrial length and increased P-DRP1S616 levels. Taken 20 together, these findings implicate STAT2 as a novel regulator of DRP1 phosphorylation at serine 616, and thus of mitochondrial fission, and suggest that there are interactions between immunity and mitochondria. This is the first study to link the innate immune system to mitochondrial dynamics and morphology. We hypothesize that variability in JAK-STAT signalling may contribute to the phenotypic heterogeneity of mitochondrial disease, and may explain why some patients with underlying mitochondrial disease decompensate after seemingly trivial viral infections. Modulating JAK-STAT activity may represent a novel 25 therapeutic avenue for mitochondrial diseases, which remain largely untreatable. This may also be relevant for more common neurodegenerative diseases, including Alzheimer’s, Huntington’s and Parkinson’s diseases, in which abnormalities of mitochondrial morphology have been implicated in disease pathogenesis

The Barbados Insulin Matters (BIM) study: Barriers to insulin therapy among a population-based sample of people with type 2 diabetes in the Caribbean island of Barbados.

AIM: The purpose of this study was to document in people with type 2 diabetes (T2DM) in Barbados, attitudes and beliefs that may result in psychological insulin resistance. METHODS: A representative, population-based, sample of 175 eligible people with T2DM 25 years of age and over was surveyed by telephone. The 20-item insulin treatment appraisal scale (ITAS) was administered (score range 20 to 100 for positive to negative perceptions). RESULTS: 117 people participated (67% response rate, 32% male, mean age 66 years, 90% Black, 22% on insulin). Of non-responders, 52 were not contactable and 6 were difficult to communicate with. Negative perceptions about insulin use included - meant a worsening of diabetes (68%), would worry family (63%), feared self-injection (58%), meant a failure in self-management (57%), injections were painful (54%), would be seen as being sicker (46%), increased hypoglycaemia risk (38%), required effort (34%), causes weight gain (27%), causes a deterioration in health (14%), and would have to give up enjoyable activities (10%). Positive perceptions were - helps good glycaemic control (78%), would prevent complications (61%) and improves health (58%). Mean total ITAS score (61.6, SD = 7.7) was lower for those on insulin compared to those not on insulin (53.7 vs. 63.8, p < 0.0001). Sex, age and diabetes diagnosis duration were not significant predictors of ITAS score. CONCLUSIONS: Multiple factors related to patient beliefs and attitudes need to be considered and addressed when initiating insulin in order to minimise psychological insulin resistance and delay. Patients using insulin had less negative perceptions than those not on insulin

Phoebe 2.0 – Triple and multiple systems

Some close binary formation theories require the presence of a third body so that the binary orbit can shrink over time. Tidal friction and Kozai cycles transfer energy from the binary to its companion, resulting in a close inner binary and a wide third body orbit. Spectroscopy and imaging studies have found 40% of binaries with periods less than 10 days, and 96% with periods less than 3 days, have a wide tertiary companion. With recent advancements in large photometric surveys, we are now beginning to detect many of these triple systems by observing tertiary eclipses or through the effect they have on the eclipse timing variations (ETVs) of the inner-binary. In the sample of 2600 Kepler EBs, we have detected the possible presence of a third body in ∼20%, including several circumbinary planets. Some multiple systems are quite dynamical and feature disappearing and reappearing eclipses, apsidal motion, and large disruptions to the inner-binary. phoebe is a freely available binary modeling code which can dynamically model all of these systems, allowing us to better test formation theories and probe the physics of eclipsing binaries