Reclaiming the energy of a schedule: models and algorithms

We consider a task graph to be executed on a set of processors. We assume that the mapping is given, say by an ordered list of tasks to execute on each processor, and we aim at optimizing the energy consumption while enforcing a prescribed bound on the execution time. While it is not possible to change the allocation of a task, it is possible to change its speed. Rather than using a local approach such as backfilling, we consider the problem as a whole and study the impact of several speed variation models on its complexity. For continuous speeds, we give a closed-form formula for trees and series-parallel graphs, and we cast the problem into a geometric programming problem for general directed acyclic graphs. We show that the classical dynamic voltage and frequency scaling (DVFS) model with discrete modes leads to a NP-complete problem, even if the modes are regularly distributed (an important particular case in practice, which we analyze as the incremental model). On the contrary, the VDD-hopping model leads to a polynomial solution. Finally, we provide an approximation algorithm for the incremental model, which we extend for the general DVFS model.Comment: A two-page extended abstract of this work appeared as a short presentation in SPAA'2011, while the long version has been accepted for publication in "Concurrency and Computation: Practice and Experience

Complement protein levels in plasma astrocyte-derived exosomes are abnormal in conversion from mild cognitive impairment to Alzheimer's disease dementia.

IntroductionLevels of complement proteins (CPs) in plasma astrocyte-derived exosomes (ADEs) that are abnormal in Alzheimer's disease (AD) have not been assessed in mild cognitive impairment (MCI).MethodsParticipants (n = 20 per group) had either MCI converting to dementia within 3 years (MCIC), MCI remaining stable over 3 years (MCIS), Alzheimer's disease, or were controls. CPs of ADEs isolated from plasmas by anti-human glutamine aspartate transporter antibody absorption were quantified by ELISAs.ResultsADE levels of C1q and C4b of the classical pathway, factor D and fragment Bb of the alternative pathway, and C5b, C3b, and C5b-C9 of both pathways were significantly higher in patients with MCIC than those with MCIS. ADE levels of inhibitory CPs decay-accelerating factor, CD46, CD59, and type 1 complement receptor were significantly lower in patients with MCIC than those with MCIS.DiscussionADE CPs are components of neurotoxic neuroinflammation that may be predictive biomarkers of MCI conversion to Alzheimer's disease

Institutions and Maker Entrepreneurship

The nascent research on the maker movement highlights the implicit assumptions embedded in the literature on entrepreneurship and innovation based on a model of closed traditional product development. Instead, the maker culture emphasizes inclusiveness, openness, sharing, and collaboration. To date, we know little about how institutional-level factors (such as intellectual property rights protection, maker culture and access to makerspaces) impact the probability of a maker hobbyist becoming an entrepreneur. We leverage the institutional perspective to examine the differing regulatory, normative and cultural elements with a cross-national study. Thus, via a leading maker community, Hackster IO, we collected data from surveying 3,139 global makers from 99 countries during 2016, providing the first quantitative evidence about the maker movement's impact on firm creation. Our results suggest that having access to makerspaces positively correlates with the likelihood of being a maker entrepreneur. Intellectual property rights protection demonstrated an inverted-U shape relationship with being an entrepreneur. This paper provides the first large quantitative evidence on the wide existence of maker entrepreneurship across the world and how intuitional factors impact the creation of maker-founded firms in different societies

Brief Announcement: Reclaiming the Energy of a Schedule, Models and Algorithms

Version longue publiée dans Concurrency and Computation: Practice and Experience.International audienceWe consider a task graph to be executed on a set of processors. We assume that the mapping is given, say by an ordered list of tasks to execute on each processor, and we aim at optimizing the energy consumption while enforcing a prescribed bound on the execution time. While it is not possible to change the allocation of a task, it is possible to change its speed. We study the complexity of the problem for different models: continuous speeds, discrete modes, distributed either arbitrarily or regularly, and VDD-hopping

A Gas Chromatograph-Pedestal Olfactometer (GC-PO) for the Study of Odor Mixtures

Gas chromatography - Olfactometry (GC-O) purifies odorants and delivers them as 1 to 2 second doses to an olfactometer where their odor properties (quale and intensity) can be studied independent of other odors. Adding an odor to the olfactometer air before combining it with the GC effluent creates an odor pedestal upon which an odorant eluting from the GC can be studied to provide insight into mixture perception. This paper describes the development and testing of a gas chromatography - pedestal olfactometer (GC-PO) that produces a Gaussian shaped distribution of one odorant in a background of constant odor composition (the pedestal). A constant pedestal composition was generated by a dynamic headspace released from poly(ethylene) glycol (PEG) solutions into the humidified air of a gas chromatograph-olfactometer (GCO). A magnetic stirrer kept the solvent at the interface in equilibrium with the remainder of the solution producing a constant (+ 10%) pedestal concentration. The resulting pedestal was then combined with a GC effluent and sent to the sniff port of the GC-O. Hexanal, octanal and decanal were analyzed by gas chromatography-mass spectrometry to test the performance and stability of the pedestal. Volatile concentrations of compounds released in the pedestal of GC-PO were linear, constant and could be turned on and off without any detectable background or residual odo

Le projet de désalinisation à Lima : des enjeux territoriaux à la transition socio-technique du secteur de l’eau

En 2013, le gouvernement péruvien annonce le premier projet d’usine de désalinisation dans le secteur public de l’eau à Lima (Pérou). L’article a pour objet l’analyse du processus d’adoption de ce projet présenté comme une innovation. Il met en évidence la convergence d’intérêts aux niveaux local et national qui contribue à amorcer une transition socio-technique dans le secteur de l’eau dans un contexte de remise en cause des grandes infrastructures hydrauliques dans les Andes. Cette analyse permet de souligner la relation dialectique, c’est-à-dire l’impact mutuel, entre les solutions de production et gestion de l’eau et le développement urbain en analysant deux dimensions centrales : la dimension territoriale ainsi que la configuration d’acteurs et leurs intérêts.In 2013, the Peruvian government announced the first seawater desalination project for public urban water service in Lima (Perú). The article looks to analyze the decision-making process that led to the adoption of the infrastructure project. The infrastructure is presented as an innovation in the national context where large Andean hydraulic infrastructures are destabilized. We analyze the convergence of multiple interests that contribute to trigger a sociotechnical transition in the water sector. This analysis allows us to underline the mutual impact between solutions for water production and management and urban development trends, especially around territorial and agency issues

Preferential adsorption to air-water interfaces: a novel cryoprotective mechanism for LEA proteins

Late embryogenesis abundant (LEA) proteins comprise a diverse family whose members play a key role in abiotic stress tolerance. As intrinsically disordered proteins, LEA proteins are highly hydrophilic and inherently stress tolerant. They have been shown to stabilize multiple client proteins under a variety of stresses, but current hypotheses do not fully explain how such broad range stabilization is achieved. Here, using neutron reflection and surface tension experiments, we examine in detail the mechanism by which model LEA proteins, AavLEA1 and ERD10, protect the enzyme citrate synthase from aggregation during freeze-thaw. We find that a major contributing factor to citrate synthase aggregation is the formation of air bubbles during the freeze-thaw process. This greatly increases the air-water interfacial area, which is known to be detrimental to folded protein stability. Both model LEA proteins preferentially adsorb to this interface and compete with citrate synthase, thereby reducing surface induced aggregation. This novel surface activity provides a general mechanism by which diverse members of the LEA protein family might function to provide aggregation protection that is not specific to the client protein.Canadian Research Council for PhD studentship + ERC gran

Epidemiological aspects of surgical site infections in an income country. The case of regional hospital center, Borgou (Benin)

ABSTRACT Background: Surgical site infection is frustrating for the care team and depressing for the patient. Objective: To determine the epidemiological aspects of surgical site infections in regional hospital, Borgou. Methods: The study was crossed with prospective data collection. Recruitment was done for six months (from February 2013 to July 2013), each patient operated in both surgical services (general surgery and maternity) consents to be followed for one month or year. The surgical site infection was defined according to the CDC/NHSN 2009. Results: The frequency of surgical site infections was 7.3% (44/603). The mean age was 30.7 ± 15.8 years with minimum and maximum of 5 months and 70 years, respectively. They were significantly (p<0.05) more common in general surgery than that of maternity and visceral surgery and obstetrics were more concerned (14/44 each); the median time to SSI onset was 7.8 ± 3.8 days. The deep incisional infection was the most frequent (34/44). The most encountered organism was Escherichia coli (64.7%); multidrug resistance was 41.2%. The healing time averaged 30.5 ± 13.8 days with minimum and maximum of 20 and 92 days. Conclusion: Monitoring measures must be taken to reduce surgical site infection at the Regional Hospital Centre of Borgou.Background: Surgical site infection is frustrating for the care team and depressing for the patient. Objective: To determine the epidemiological aspects of surgical site infections in regional hospital, Borgou. Methods: The study was crossed with prospective data collection. Recruitment was done for six months (from February 2013 to July 2013), each patient operated in both surgical services (general surgery and maternity) consents to be followed for one month or year. The surgical site infection was defined according to the CDC/NHSN 2009. Results: The frequency of surgical site infections was 7.3% (44/603). The mean age was 30.7 ± 15.8 years with minimum and maximum of 5 months and 70 years, respectively. They were significantly (p<0.05) more common in general surgery than that of maternity and visceral surgery and obstetrics were more concerned (14/44 each); the median time to SSI onset was 7.8 ± 3.8 days. The deep incisional infection was the most frequent (34/44). The most encountered organism was Escherichia coli (64.7%); multidrug resistance was 41.2%. The healing time averaged 30.5 ± 13.8 days with minimum and maximum of 20 and 92 days. Conclusion: Monitoring measures must be taken to reduce surgical site infection at the Regional Hospital Centre of Borgou

The letters of an English lady to her father 1837-1842

The eight letters which are reproduced here are part of the correspondence between Fanny Liddell, nee Sconce, and her father Robert Sconce . During most of these years , he appears to have lived in Malta and these letters were written to him whilst Fanny, her husband John, her sons Johnny and later Bobby, were travelling in Europe or at home in England. One letter was written by her in Malta when her father was in Switzerland . They are interesting because of the warmth, attractiveness, and spontaneity of the writer's personality which still comes very much alive after the world has seen tremendous changes in the last century and a half. They also give a fascinating insight into the business of European travelling at that time. The various references to packet boat sailing and the times taken then for various journeys may be useful to postal historians. Unfortunately, these eight letters have now been dispersed. However , I am glad that before this happened, I had the opportunity to record this little vignette of life in the Europe of 140 years agonon peer-reviewe