Morse Inequalities for Orbifold Cohomology

This paper begins the study of Morse theory for orbifolds, or more precisely for differentiable Deligne-Mumford stacks. The main result is an analogue of the Morse inequalities that relates the orbifold Betti numbers of an almost-complex orbifold to the critical points of a Morse function on the orbifold. We also show that a generic function on an orbifold is Morse. In obtaining these results we develop for differentiable Deligne-Mumford stacks those tools of differential geometry and topology -- flows of vector fields, the strong topology -- that are essential to the development of Morse theory on manifolds

The development and applications of ultrafast electron nanocrystallography

We review the development of ultrafast electron nanocrystallography as a method for investigating structural dynamics for nanoscale materials and interfaces. Its sensitivity and resolution are demonstrated in the studies of surface melting of gold nanocrystals, nonequilibrium transformation of graphite into reversible diamond-like intermediates, and molecular scale charge dynamics, showing a versatility for not only determining the structures, but also the charge and energy redistribution at interfaces. A quantitative scheme for three-dimensional retrieval of atomic structures is demonstrated with few-particle (< 1000) sensitivity, establishing this nanocrystallographic method as a tool for directly visualizing dynamics within isolated nanomaterials with atomic scale spatio-temporal resolution.Comment: 33 pages, 17 figures (Review article, 2008 conference of ultrafast electron microscopy conference and ultrafast sciences

An End-to-End Task Allocation Framework for Autonomous Mobile Systems

This work aims to unravel the problem of task allocation and planning for multi-agent systems with a particular interest in promoting adaptability. We proposed a novel end-to-end task allocation framework employing reinforcement learning methods to replace the handcrafted heuristics used in previous works. The proposed framework achieves high adaptability and also explores more competitive results. Learning experiences from the feedback help to reach the advantages. The systematic objectives are adjustable and responsive to the reward design intuitively. The framework is validated in a set of tests with various parameter settings, where adaptability and performance are demonstrated

Bulk modulus of air content oil in a hydraulic cylinder

ABSTRACT A model of oil with entrained air content is developed which considers fluid compression and the subsequent dissolving of mixed entrained air. According to the model the mixed entrained air affects the &quot;gross&quot; bulk modulus below some critical pressure, but has no effect above this value due to the complete dissolving of the entrained air into solution. The critical pressure is shown to be proportional to the square root of the amount of the initial mixed entrained air. The temporal pressure gradient has also a substantial effect on the critical pressure value and thus on the bulk modulus. The critical pressure value increases but tends towards an upper value with increasing temporal pressure gradient (a true dynamic condition); the opposite occurs when the pressure gradient decreases as the critical pressure converges to a lower value (essentially a static value). Thus regions of static and dynamic bulk modulus can be established. The model predicts that the upper critical pressure value is some 1.8 times that of the static one. Experiments have been designed to verify the feasibility of the model by measuring the temporal pressure gradient against the variation of compressed oil volume. It is demonstrated that the model is verified not only for the case of positive pressures (above atmospheric pressure) but also for pressures less than atmosphere. Finally a comparison of the proposed model is made with those proposed in the literature. The bulk modulus predicted by the proposed model is a little larger than these given in literature. The reason for such difference is attributed to the result of air being dissolved into oil

Interplay of Hypoxia-Inducible Factors and Oxygen Therapy in Cardiovascular Medicine

Mammals have evolved to adapt to differences in oxygen availability. Although systemic oxygen homeostasis relies on respiratory and circulatory responses, cellular adaptation to hypoxia involves the transcription factor hypoxia-inducible factor (HIF). Given that many cardiovascular diseases involve some degree of systemic or local tissue hypoxia, oxygen therapy has been used liberally over many decades for the treatment of cardiovascular disorders. However, preclinical research has revealed the detrimental effects of excessive use of oxygen therapy, including the generation of toxic oxygen radicals or attenuation of endogenous protection by HIFs. In addition, investigators in clinical trials conducted in the past decade have questioned the excessive use of oxygen therapy and have identified specific cardiovascular diseases in which a more conservative approach to oxygen therapy could be beneficial compared with a more liberal approach. In this Review, we provide numerous perspectives on systemic and molecular oxygen homeostasis and the pathophysiological consequences of excessive oxygen use. In addition, we provide an overview of findings from clinical studies on oxygen therapy for myocardial ischaemia, cardiac arrest, heart failure and cardiac surgery. These clinical studies have prompted a shift from liberal oxygen supplementation to a more conservative and vigilant approach to oxygen therapy. Furthermore, we discuss the alternative therapeutic strategies that target oxygen-sensing pathways, including various preconditioning approaches and pharmacological HIF activators, that can be used regardless of the level of oxygen therapy that a patient is already receiving

Augmentation Index Derived from Peripheral Arterial Tonometry Correlates with Cardiovascular Risk Factors

Background. Augmentation index (AIx) is traditionally obtained from pressure waveforms via arterial applanation tonometry. We sought to evaluate the association between AIx obtained from peripheral arterial tonometry (PAT) with cardiovascular risk factors (CRF) and coronary artery disease (CAD). Methods. 186 patients were enrolled in the study. The presence or absence of CRFs and CAD was assessed in each subject. AIx was calculated by an automated algorithm averaging pulse wave amplitude data obtained via PAT. Central blood pressures were assessed in a subset of patients undergoing clinically indicated cardiac catheterization. Results. An association was observed between AIx and age, heart rate, systolic blood pressure, mean arterial pressure, pulse pressure, body weight and body mass index. AIx was significantly lower in patients with <3 CRFs compared to those with >5 CRFs ( P = .02). CAD+ patients had significantly higher AIx compared to CAD− patients ( P = .008). Area under the ROC curve was 0.604 (P < .01). In patients undergoing cardiac catheterization, after adjusting for age, height and heart rate, AIx was a significant predictor of aortic systolic and pulse pressures (P < .05) Conclusion. AIx derived from PAT correlates with cardiac risk factors and CAD. It may be a useful measure of assessing overall risk for coronary artery disease

Inteligência Artificial e Direito: o Fantasma na Máquina

Tendo-se que a inteligência artificial é uma tecnologia em construção, atraindo o interesse de muitos pesquisadores, inclusive de aplicadores do direito, faz-se, portanto, necessária que uma discussão a respeito dos fundamentos e das possíveis aplicações ao direito seja realizada – uma vez que, caso a promessa da tecnologia torne-se realidade, o direito, aliado à inteligência artificial, ganhará em grande proporção

Bandgap engineering of organic semiconductors for highly efficient photocatalytic water splitting

The bandgap engineering of semiconductors, in particular low‐cost organic/polymeric photocatalysts could directly influence their behavior in visible photon harvesting. However, an effective and rational pathway to stepwise change of the bandgap of an organic/polymeric photocatalyst is still very challenging. An efficient strategy is demonstrated to tailor the bandgap from 2.7 eV to 1.9 eV of organic photocatalysts by carefully manipulating the linker/terminal atoms in the chains via innovatively designed polymerization. These polymers work in a stable and efficient manner for both H2 and O2 evolution at ambient conditions (420 nm < λ < 710 nm), exhibiting up to 18 times higher hydrogen evolution rate (HER) than a reference photocatalyst g‐C3N4 and leading to high apparent quantum yields (AQYs) of 8.6%/2.5% at 420/500 nm, respectively. For the oxygen evolution rate (OER), the optimal polymer shows 19 times higher activity compared to g‐C3N4 with excellent AQYs of 4.3%/1.0% at 420/500 nm. Both theoretical modeling and spectroscopic results indicate that such remarkable enhancement is due to the increased light harvesting and improved charge separation. This strategy thus paves a novel avenue to fabricate highly efficient organic/polymeric photocatalysts with precisely tunable operation windows and enhanced charge separation

Gestão da Inovação: Uma pesquisa no segmento de padarias da Grande Natal.

 presente estudo objetivou perceber como as empresas de micro e pequeno porte do segmento de panificação participantes do Programa ALI na Grande Natal lidam com a promoção de um ambiente propício à inovação. Para tanto, desenvolveu-se um estudo exploratório e descritivo, de abordagem quantitativa baseado no estudo de Bachmann e Destefani (2008) que propõe uma sistemática de mensuração do grau de inovação em MPE’s baseado nas 12 Dimensões da Inovação descritas por Sawhney et al. (2006), da Kellogg School of Management (EUA) acrescida à Dimensão “Ambiência Inovadora”. De um universo de cento e noventa e seis empresas, foram visitadas quarenta e uma, o que reflete num índice amostral de 20,92%. Os resultados da pesquisa apontaram que no mercado da Grande Natal, o setor produtivo de panificação relaciona-se pouco com o conhecimento e aplicabilidade de um modelo de gestão que favoreça um ambiente propício à inovação. Cenário que expõe uma miríade de oportunidades de avanços em termos de disseminação e uso de: (a) fontes de conhecimento; (b) formas de financiamento da inovação; (c) sistema de coleta de ideias; bem como o incentivo ao (d) constante e sistemático desenvolvimento de novos produtos e processos