Low dielectric constant Parylene-F-like films for intermetal dielectric applications

Cataloged from PDF version of article.We report on the dielectric properties and thermal stability of thin polymer films that art: suitable candidates for replacing silicon dioxide as the intermetal dielectric material in integrated circuits. Parylene-F-Iike films, (-CF2-C6H4-CF2-)(n), were produced by plasma deposition from a mixture of Ar and 1,4-bis(trifluoromethyl)benzene (CF3-C6H4-CF3) discharges and characterized using infrared absorption spectroscopy, spectroscopic ellipsometry, and capacitance measurements. The dielectric constant and the magnitude of the electronic and ionic contributions to the dielectric constant were determined through capacitance measurements and Kramers-Kronig analysis of the infrared absorption data. The film's dielectric constant ranges between 2 and 2.6 depending on the deposition conditions and the largest contribution to the dielectric constant is electronic. The films deposited at 300 degrees C are stable above 400 degrees C and further optimization could push this limit to as high as 500 degrees C. (C) 1999 American Institute of Physics

Multidisciplinary contributions towards an evolutive interpretation of bipolar disorders: Could it be the pathological drift of a potentially adaptive condition?

This paper tries to summarize the results of studies from different areas of knowledge supporting the idea that temperamental traits, such as "reckless/hyper-exploratory"attitudes, commonly believed to be associated with psychopathology, surprisingly turn out as adaptive under specific stress conditions. In particular, this paper analyzes an ethologic line of research on primates suggesting models for a sociobiological interpretation of mood disorders in humans; a study that found high frequencies of a genetic variance associated with bipolar disorder in people without bipolar disorder but with hyperactivity/novelty-seeking traits; the outcomes of socio-anthropological-historical surveys on the evolution of mood disorders in Western countries in the last centuries; surveys on changing societies in Africa and African migrants in Sardinia; and studies that found higher frequencies of mania and subthreshold mania among Sardinian immigrants in Latin American megacities. Although it is not unequivocally accepted that the prevalence of mood disorders has increased, it would be logical to suppose that a nonadaptive condition should have disappeared over time; mood disorders, on the contrary, persist and their prevalence might have even increased. This new interpretation could lead to counter discrimination and stigma towards people suffering from the disorder and would be a central point in psychosocial treatments in addition to pharmacological therapy. Our aim is to hypothesize that bipolar disorder, strongly characterized by these traits, may be the result of the interaction between genetic characteristics, not necessarily pathological, and specific environmental conditions rather than a mere product of an aberrant genetic profile. If mood disorders were mere nonadaptive conditions, they would have disappeared over time; however, their prevalence paradoxically persists if not even increases over time. The hypothesis that bipolar disorder may result from the interaction between genetic characteristics, not necessarily pathological, and specific environmental factors seems more credible than considering bipolar disorder as a mere product of an aberrant genetic profile

Cognitive function and mood at high altitude following acclimatization and use of supplemental oxygen and adaptive servoventilation sleep treatments.

Impairments in cognitive function, mood, and sleep quality occur following ascent to high altitude. Low oxygen (hypoxia) and poor sleep quality are both linked to impaired cognitive performance, but their independent contributions at high altitude remain unknown. Adaptive servoventilation (ASV) improves sleep quality by stabilizing breathing and preventing central apneas without supplemental oxygen. We compared the efficacy of ASV and supplemental oxygen sleep treatments for improving daytime cognitive function and mood in high-altitude visitors (N = 18) during acclimatization to 3,800 m. Each night, subjects were randomly provided with ASV, supplemental oxygen (SpO2 > 95%), or no treatment. Each morning subjects completed a series of cognitive function tests and questionnaires to assess mood and multiple aspects of cognitive performance. We found that both ASV and supplemental oxygen (O2) improved daytime feelings of confusion (ASV: p < 0.01; O2: p < 0.05) and fatigue (ASV: p < 0.01; O2: p < 0.01) but did not improve other measures of cognitive performance at high altitude. However, performance improved on the trail making tests (TMT) A and B (p < 0.001), the balloon analog risk test (p < 0.0001), and the psychomotor vigilance test (p < 0.01) over the course of three days at altitude after controlling for effects of sleep treatments. Compared to sea level, subjects reported higher levels of confusion (p < 0.01) and performed worse on the TMT A (p < 0.05) and the emotion recognition test (p < 0.05) on nights when they received no treatment at high altitude. These results suggest that stabilizing breathing (ASV) or increasing oxygenation (supplemental oxygen) during sleep can reduce feelings of fatigue and confusion, but that daytime hypoxia may play a larger role in other cognitive impairments reported at high altitude. Furthermore, this study provides evidence that some aspects of cognition (executive control, risk inhibition, sustained attention) improve with acclimatization

Fabrication and Characterization of a Vertically-Oriented Graphene Supercapacitor

Supercapacitors, otherwise known as electrical double layer capacitors, are a new type of electrochemical capacitor whose storage capacity is governed by two principals: the electrostatic storage achieved by a separation of charge at the interface of an electrode with an electrolytic solution, and pseudocapacitance, whose electrical energy is achieved by faradaic redox reactions. This project reports the synthesis and characterization of vertically-oriented graphene grown on copper substrates as electrodes in electric double-layer capacitor. Graphene is a two-dimensional pure carbon material with a high potential for energy storage. With vertically-grown graphene, an exponentially-larger surface area is made available, allowing an increase in electrostatic storage. Nano-sheets of carbon were fabricated via plasma-enhanced chemical vapor deposition and characterized using cyclic voltammetry and Raman spectrometry. Specific capacitance was compared using with both aqueous and organic electrolytes, as well as variations with growth conditions and scan rates. Applications of the supercapacitor range from energy storage in space exploration to consumer electronics and transportation

Health systems thinking: A new generation of research to improve healthcare quality.

Hannah Leslie and colleagues of the High-Quality Health Commission discuss in an Editorial the findings from their report that detail the improvements needed to prevent declines in individuals' health as the scope and quality of health systems increase. Patient-centered care at the population level, improved utility of research products, and innovative reporting tools to help guide the development of new methods are key to improved global healthcare

Toward a New Technology and Policy Program (TPP) Curriculum

The mission of the MIT Technology and Policy Program (TPP) is: “Provide an integrative education to scientists and engineers who wish to lead in the development and implementation of responsible strategies and policies for exploitation of technology for the benefit of their communities” (Hastings, 2000). Embedded in the TPP mission statement are several educational requirements: (1) a comprehensive and diverse set of solid analytical skills needed to develop and assess strategies and policies, (2) the flexibility to manage the conflicting interests and values that are present at all stages of the policy process, and (3) the ability to provide leadership at each stage in the policy process. With these concepts in mind, the TPP Curriculum Development Committee will work to place TPP at the forefront of educating the “leaders (researchers and practitioners) of the fields of technology and policy studies” (Hastings, 2000)

Addressing Budget and Debt Vulnerability amidst COVID-19: Policy Pathways for Nigeria

Budget constraints and rising debt burdens in Nigeria are macroeconomic issues that have to be addressed sustainably. Such issues can clog the wheels of progress on economic growth and sustainable development in the country. This policy brief considers the disconnection between economic growth objectives and national budgeting amidst closely related problems of limited revenues, declining oil price, and the resulting debt burdens. Some options for policymakers to address the challenges as a vehicle to ensure better human capital outcomes are highlighted. These include: redefining Nigeria's objectives for budgeting; shifting emphasis from budgetary allocations to funding; addressing inadequate revenue generation; and financing of the national budget. Others entail: improving budget implementation towards achieving the budgeting objectives; orientation of citizens to understand that federal government budgets should fund federal projects alone; and monitoring of sub-national government

Factors Associated with Ivermectin Non-Compliance and Its Potential Role in Sustaining Onchocerca volvulus Transmission in the West Region of Cameroon

Background Community Directed Treatment with ivermectin is the cornerstone of current efforts to eliminate onchocerciasis. However recent studies suggest there are foci where long-term annual distribution of the drug alone has failed to ensure elimination thresholds are reached. It is important to achieve high levels of compliance in order to obtain elimination targets. An epidemiological and entomological evaluation conducted in the western region of Cameroon in 2011 revealed that two health districts remained with a high prevalence of infection, despite long-term distribution of ivermectin since 1996. This paper explores potential factors that may have contributed to the non-interruption of transmission, focusing on ivermectin treatment compliance and the importance of systematic non-compliance within the population. Methodology/Principal findings A mixed methods approach was used, including a population-based survey to assess treatment compliance and factors associated and qualitative assessments including focus group discussions and in-depth interviews with key programme stakeholders and drug distributors. Compliance was reported at 71.2%(95%CI: 61.7–79.2%;n = 853/1198). The key factors related to compliance in the most recent round related to either programmatic and delivery issues, primarily absenteeism at the time of the campaign or alternatively individual determinants. An individual’s experience of side effects in the past was strongly associated with non-compliance to ivermectin. Other factors included ethnicity, how long lived in the village and age. There was a high percentage of reported systematic non-compliance at 7.4% (95% CI: 4.3–12.3%; n = 86/1165), higher amongst females. This group may be important in facilitating the sustainment of on-going transmission