2,410 research outputs found
Horocyclic invariance of Ruelle resonant states for contact Anosov flows in dimension 3
We show that for smooth contact Anosov flows in dimension 3, the resonant
states associated to the first band of Ruelle resonances are distributions that
are killed by the unstable derivative.Comment: 23 page
Homologie de contact des varietes toroidales
We show that contact homology distinguishes infinitely many tight contact
structures on any orientable, toroidal, irreducible 3-manifold. As a
consequence of the contact homology computations, on a very large class of
toroidal manifolds, all known examples of universally tight contact structures
with nonvanishing torsion satisfy the Weinstein conjecture.
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On montre que l'homologie de contact distingue une infinite de structures de
contact tendues sur toute variete toroidale irreductible et orientable de
dimension trois. En consequence des calculs d'homologie de contact, sur une
tres large classe de varietes toroidales, tous les exemples de structures de
contact universellement tendues de torsion non nulle connus verifient la
conjecture de Weinstein.Comment: Published by Geometry and Topology at
http://www.maths.warwick.ac.uk/gt/GTVol9/paper9.abs.html Version 3: one minor
correctio
Hyperadrenalism in Childhood and Adolescence
Hyperadrenalism in childhood and adolescence has unique features that influence diagnosis and management. We reviewed our experience with 18 patients, ranging in age from 18 months to 18 years. Nine had bilateral adrenal hyperplasia, eight had adrenal neoplasms, and one had micronodular hyperplasia. Patients with congenital adrenal hyperplasia and hyperaldosteronism were excluded. Six patients with Cushing's disease diagnosed in earlier years were treated by total adrenalectomy and recently two patients underwent transsphenoidal removal of pituitary tumors. Bilateral adrenalectomy was carried out in one patient with micronodular hyperplasia and in a second because of elevated adrenocorticotrophic hormone (ACTH) levels from an undefined source. Eight patients had adrenal neoplasms, including five adenomas and three carcinomas. We found no reliable criteria to differentiate before surgery between adrenal adenomas and adrenal carcinomas. The most recognizable characteristic of malignancy was tumor size, specifically weight greater than 75 gms. Of the three patients with adrenal carcinoma, one expired 20 months after adrenalectomy and 8 months after receiving palliative partial hepatectomy for liver metastasis. Two patients are well with normal growth and development at 11 and 20 years following adrenalectomy. With the exception of one patient who died 6 years after surgery from a glioblastoma multiforme, all patients with adrenal adenomas are well. Eight patients underwent bilateral adrenalectomy for hypercortisolism. Five of the six who have reached their adult stature are significantly stunted. Four of six patients with Cushing's disease, treated by total adrenalectomy, have developed Nelson's syndrome at 2, 6, 10, and 12 years after surgery. Of the two patients undergoing transsphenoidal surgery, one had recurrent disease at 2 years and was treated by pituitary irradiation with recovery. The patients undergoing adrenalectomy for micronodular hyperplasia and ectopic ACTH are well at 2 and 4 years, respectively. Cushing's disease in children and adolescents is best treated by transsphenoidal removal of the pituitary adenoma. Adrenalectomy, once the most accepted approach, plays a secondary role and is indicated primarily in micronodular adrenal hyperplasia, in patients with ectopic ACTH production of an undefined source, and in recurrent Cushing's disease following prior pituitary irradiation. The high incidence of Nelson's syndrome in children treated by adrenalectomy mandates that patients at risk be monitored lifelong for the progression of a pituitary tumor. Irradiation should be considered in patients with recurrent Cushing's disease following transsphenoidal surgery and as an alternative to hypophysectomy in the prepubertal patient with Nelson's syndrome. Adrenalectomy remains the treatment of choice for adrenal tumors with the prognosis being excellent in neoplasms weighing less than 75 gms
Trade sustainability impact assessment (SIA) on the comprehensive economic and trade agreement (CETA) between the EU and Canada: Final report
Commissioned by the European Commission, the Final Report for the EU-Canada Sustainability Impact Assessment (SIA) on the EU-Canada Comprehensive Economic and Trade Agreement (CETA) provides a comprehensive assessment of the potential impacts of trade liberalisation under CETA. The analysis assesses the economic, social and environmental impacts in Canada and the European Union in three main sectors, sixteen sub-sectors and across seven cross-cutting issues. It predicts a number of macro-economic and sector-specific impacts. The macro analysis suggests the EU may see increases in real GDP of 0.02-0.03% in the long-term from CETA, whereas Canada may see increases of 0.18-0.36%. The Investment section of the report suggests these numbers could be higher when factoring in investment increases. At the sectoral level, the study predicts the greatest gains in output and trade to be stimulated by services liberalisation and by the removal of tariffs applied on sensitive agricultural products. It also suggests CETA could have a positive social impact if it includes provisions on the ILO’s Core Labour Standards and Decent Work Agenda. The study also details a variety of impacts in various “cross-cutting” components of CETA. It finds CETA would stimulate investment in Canada, and to a lesser extent in the EU; and finds costs outweigh the benefits of including controversial NAFTA-style investor-state dispute settlement (ISDS) provisions in CETA. It predicts potentially imbalanced benefits from a government procurement (GP) chapter. The study assumes CETA will lead to an upward harmonisation in intellectual property rights (IPR) regulations, particularly in Canada, which will have a number of effects. It predicts some notable impacts in terms of competition policy, as well as trade facilitation, free circulation of goods and labour mobility.EU-Canada Sustainability Impact Assessment; SIA; EU-Canada Comprehensive Economic and Trade Agreement; Comprehensive Economic and Trade Agreement; CETA; government procurement; investor-state provisions; ISDS; competition policy; Dan Prud'homme; trade impact assessment
Catalytic fast pyrolysis of biomass over microporous and hierarchical zeolites: characterization of heavy products
The
conversion of lignocellulosic biomass by catalytic fast pyrolysis
(CFP) is a promising route to producing green aromatics and sustainable
biofuels. The zeolite catalysts present a strong ability to produce
light aromatics but also heavy products. In this work, these heavy
products are monitored by a well-established petroleomic approach.
The selectivity toward the heavy bio-oil components of both a common
HZSM-5 zeolite and a hierarchical zeolite was investigated. Part of
the molecular species from lignin derivatives is still present in
the upgraded bio-oils. Deoxygenation and aromatization are the main
modifications of the heavy compounds caused by zeolites, especially
for the sugar derivatives. These effects are stronger for the hierarchical
zeolite for which numerous heavy hydrocarbons (not oxygenated) are
generated due to enhanced mass transfers within the crystallites.
Moreover, this catalyst demonstrates a better stability upon an increase
in the biomass-to-catalyst ratio
AutoML for Climate Change: A Call to Action
The challenge that climate change poses to humanity has spurred a rapidly
developing field of artificial intelligence research focused on climate change
applications. The climate change AI (CCAI) community works on a diverse,
challenging set of problems which often involve physics-constrained ML or
heterogeneous spatiotemporal data. It would be desirable to use automated
machine learning (AutoML) techniques to automatically find high-performing
architectures and hyperparameters for a given dataset. In this work, we
benchmark popular AutoML libraries on three high-leverage CCAI applications:
climate modeling, wind power forecasting, and catalyst discovery. We find that
out-of-the-box AutoML libraries currently fail to meaningfully surpass the
performance of human-designed CCAI models. However, we also identify a few key
weaknesses, which stem from the fact that most AutoML techniques are tailored
to computer vision and NLP applications. For example, while dozens of search
spaces have been designed for image and language data, none have been designed
for spatiotemporal data. Addressing these key weaknesses can lead to the
discovery of novel architectures that yield substantial performance gains
across numerous CCAI applications. Therefore, we present a call to action to
the AutoML community, since there are a number of concrete, promising
directions for future work in the space of AutoML for CCAI. We release our code
and a list of resources at
https://github.com/climate-change-automl/climate-change-automl
Decision-making in sustainable uban mobility planning: Common practice and future directions
This paper highlights the challenges for cities in selecting sustainable and cost-effective transport and mobility measures. Thereby it shall provoke thought on the implications for decision-making resulting from Sustainable Urban Mobility Plans. Firstly, an understanding of the challenges of determining a transport project’s viability will be conveyed. Secondly, the paper presents five case studies of sustainable urban mobility planning and the role of project appraisal in those policy-making processes.In discussing the challenges of traditional project-appraisal and examining actual local decision-making, the paper finds some crucial challenges in the appraisal of small-scale sustainable transport activities. It concludes by highlighting potential implications of these
Stabilization of Li-Rich Disordered Rocksalt Oxyfluoride Cathodes by Particle Surface Modification
Promising theoretical capacities and high voltages are offered by Li-rich disordered rocksalt oxyfluoride materials as cathodes in lithium-ion batteries. However, as has been discovered for many other Li-rich materials, the oxyfluorides suffer from extensive surface degradation, leading to severe capacity fading. In the case of LiVOF, we have previously determined this to be a result of detrimental reactions between an unstable surface layer and the organic electrolyte. Herein, we present the protection of LiVOF particles with AlF surface modification, resulting in a much-enhanced capacity retention over 50 cycles. While the specific capacity for the untreated material drops below 100 mA h g after only 50 cycles, the treated materials retain almost 200 mA h g. Photoelectron spectroscopy depth profiling confirms the stabilization of the active material surface by the surface modification and reveals its suppression of electrolyte decomposition
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