328 research outputs found

    A long and winding road: a brief history of the idea of a ‘government of national unity’ in Timor-Leste and its current implications

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    Abstract In this Discussion Paper, I consider first the academic debate on the establishment of democracy and the role of political competition and cooperation as a background to the current Timorese government formula. This is followed by a brief historical tour of the idea of institutional inclusion in the Timorese recent past (including actual opposition to it) in order to frame the following discussion of some problems that the inauguration of a new form of government may pose in the process of democratic consolidation. I shall then address the rationale for change that may explain the decision to revert to the new formula, whose merits and limitations will also be discussed. Finally, one and a half years after the inauguration of the new government, Timor- Leste has been shaken by political events that call into question whether the scope of ‘inclusion’ of its basis is actually so broad as to embody ‘national unity’, as important players (such as President Taur Matan Ruak) appear to be challenging critical decisions of Rui Maria de Araújo and his government. The end of History is not in sight

    Unraveling the paradox of intensity-dependent DVS pixel noise

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    Dynamic vision sensor (DVS) event camera output is affected by noise, particularly in dim lighting conditions. A theory explaining how photon and electron noise affect DVS output events has so far not been developed. Moreover, there is no clear understanding of how DVS parameters and operating conditions affect noise. There is an apparent paradox between the real noise data observed from the DVS output and the reported noise measurements of the logarithmic photoreceptor. While measurements of the logarithmic photoreceptor predict that the photoreceptor is approximately a first-order system with RMS noise voltage independent of the photocurrent, DVS output shows higher noise event rates at low light intensity. This paper unravels this paradox by showing how the DVS photoreceptor is a second-order system, and the assumption that it is first-order is generally not reasonable. As we show, at higher photocurrents, the photoreceptor amplifier dominates the frequency response, causing a drop in RMS noise voltage and noise event rate. We bring light to the noise performance of the DVS photoreceptor by presenting a theoretical explanation supported by both transistor-level simulation results and chip measurements.Comment: Presented in 2021 International Image Sensor Workshop (IISW

    Feedback control of event cameras

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    Dynamic vision sensor event cameras produce a variable data rate stream of brightness change events. Event production at the pixel level is controlled by threshold, bandwidth, and refractory period bias current parameter settings. Biases must be adjusted to match application requirements and the optimal settings depend on many factors. As a first step towards automatic control of biases, this paper proposes fixed-step feedback controllers that use measurements of event rate and noise. The controllers regulate the event rate within an acceptable range using threshold and refractory period control, and regulate noise using bandwidth control. Experiments demonstrate model validity and feedback control

    Utility and Feasibility of a Center Surround Event Camera

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    Copper complex nanoformulations featuring highly promising therapeutic potential in murine melanoma models

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    Aim: Preclinical evaluation of a cytotoxic copper(II) complex formulated in long circulating nanoliposomes for melanoma treatment. Materials & methods: Liposomal nanoformulations of the copper complex were characterized in terms of thermodynamic behavior (differential scanning calorimeter), pH-sensitivity (spectrophotometry) and antiproliferative effects against murine melanoma B16F10 cells in vitro. Preclinical studies were performed in a C57BL/6 syngeneic melanoma model. Results: Nanoformulations were thermodynamically stable, and CHEMS-containing nanoliposomes were pH-sensitive and preserved the antiproliferative properties of the copper compound. These nanoformulations significantly impaired tumor progression in vivo, devoid of toxic side effects, compared with control mice or mice treated with the free metallodrug. Conclusion: Copper complex-containing nanoliposomes demonstrate high anticancer efficacy and safety, constituting a step forward to the development of more effective therapeutic strategies against melanoma

    A 23μW Solar-Powered Keyword-Spotting ASIC with Ring-Oscillator-Based Time-Domain Feature Extraction

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    Voice-controlled interfaces on acoustic Internet-of-Things (IoT) sensor nodes and mobile devices require integrated low-power always-on wake-up functions such as Voice Activity Detection (VAD) and Keyword Spotting (KWS) to ensure longer battery life. Most VAD and KWS ICs focused on reducing the power of the feature extractor (FEx) as it is the most power-hungry building block. A serial Fast Fourier Transform (FFT)-based KWS chip [1] achieved 510nW; however, it suffered from a high 64ms latency and was limited to detection of only 1-to-4 keywords (2-to-5 classes). Although the analog FEx [2]–[3] for VAD/KWS reported 0.2μW-to-1 μW and 10ms-to-100ms latency, neither demonstrated >5 classes in keyword detection. In addition, their voltage-domain implementations cannot benefit from process scaling because the low supply voltage reduces signal swing; and the degradation of intrinsic gain forces transistors to have larger lengths and poor linearity

    Cardiopatia Congenita em Criancas com Sindrome de Down: O que Mudou nas Ultimas Tres Decadas?

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    INTRODUCTION: The prevalence of Down syndrome has increased in the last 30 years; 55% of these children have congenital heart disease.MATERIAL AND METHODS: A retrospective longitudinal cohort study; clinical data from 1982 to 2013 databases with the diagnosis of Down syndrome or trisomy 21 in a reference hospital in pediatric cardiology and cardiac surgery.OBJECTIVE: to assess the progress in the last three decades of cardiological care given to children with Down syndrome and congenital heart disease.RESULTS: We studied 102 patients with Down syndrome and congenital heart disease subjected to invasive therapy: corrective or palliative cardiac surgery and therapeutic catheterization. The referral age was progressively earlier in patients referred in the first year of life. The most frequent diagnosis was complete atrioventricular sptal defect (41%). There was a trend towards increasingly early corrective surgery in patients under 12 months (p < 0.001). Since 2000, the large majority of patients were operated before reaching six months of age. The main cardiac complications were rhythm dysfunction and low output. More frequent noncardiac complications were pulmonary and infectious. The 30-day mortality rate was 3/102 cases (2.9%). Of patients in follow-up, 89% are in NYHA class I.DISCUSSION AND CONCLUSION: The early surgical correction seen over the past 15 years follows the approach suggested in the literature. The observed 30-day mortality rate is overlapping international results. Patients with Down syndrome subjected to corrective surgery of congenital heart disease have an excellent long-term functional capacity.Introducao: A prevalencia da sindrome de Down tem aumentado nos ultimos 30 anos; 55% destas criancas apresentam cardiopatiacongenita. Material e Metodos: Estudo retrospetivo longitudinal de coorte; dados clinicos obtidos em bases de dados de 1982 a 2013 com odiagnostico de sindrome de Down ou trissomia 21 num hospital de referencia em cardiologia pediatrica e cirurgia cardiaca. Objetivo: Avaliar a evolucao, nas ultimas tres decadas, dos cuidados cardiologicos prestados as criancas com sindrome de Down ecardiopatia congenita.Resultados: Estudamos 102 doentes com sindrome de Down e cardiopatia congenita submetidos a terapeutica invasiva: cirurgiacardiaca corretiva, paliativa e cateterismo terapeutico. Em doentes referenciados no primeiro ano de vida, a referenciacao foi cadavez mais precoce. O diagnostico mais frequente foi o defeito completo do septo auriculo-ventricular (41%). Verificou-se uma tendenciapara cirurgia corretiva cada vez mais precoce em doentes abaixo dos 12 meses (p < 0,001). A partir de 2000, a grande maioria dosdoentes foi operada antes dos seis meses de idade. As principais complicacoes cardiacas foram alteracoes de ritmo e baixo debito eas principais nao cardiacas foram pulmonares e infeciosas. A taxa de mortalidade a 30 dias foi de 3/102 casos (2,9%). Dos doentesem follow-up, 89% estao em classe funcional I da NYHA. Discussao e Conclusao: A correcao cirurgica mais precoce verificada nos ultimos 15 anos vai ao encontro do proposto na literatura. Ataxa de mortalidade a 30 dias verificada e sobreponivel aos resultados internacionais. Os doentes com sindrome de Down submetidosa cirurgia corretiva de cardiopatia congenita apresentam uma excelente capacidade funcional a longo prazo.info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/publishedVersio

    Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

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    Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

    Rising rural body-mass index is the main driver of the global obesity epidemic in adults

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    Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.Peer reviewe

    Experimental methods to predict dynamic vision sensor event camera performance

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    Dynamic vision sensors (DVS) represent a promising new technology, offering low power consumption, sparse output, high temporal resolution, and wide dynamic range. These features make DVS attractive for new research areas including scientific and space-based applications; however, more precise understanding of how sensor input maps to output under real-world constraints is needed. Often, metrics used to characterize DVS report baseline performance by measuring observable limits but fail to characterize the physical processes at the root of those limits. To address this limitation, we describe step-by-step procedures to measure three important performance parameters: (1) temporal contrast threshold, (2) cutoff frequency, and (3) refractory period. Each procedure draws inspiration from previous work, but links measurements sequentially to infer physical phenomena at the root of measured behavior. Results are reported over a range of brightness levels and user-defined biases. The threshold measurement technique is validated with test-pixel node voltages, and a first-order low-pass approximation of photoreceptor response is shown to predict event cutoff temporal frequency to within 9% accuracy. The proposed method generates lab-measured parameters compatible with the event camera simulator v2e, allowing more accurate generation of synthetic datasets for innovative applications
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