41 research outputs found
Zeros, Critical Points, and Coefficients of Random Functions
Traditional approaches to the study of random polynomials and random analytic functions have focussed on answering questions regarding the behavior and/or location of zeros of these functions, where the randomness in these functions arises from the choice of coefficients. In this thesis, we shall flip this model - we consider random polynomials and random analytic functions where the source of randomness is in the choice of zeros. While first chapter is devoted to an introduction into the field, in the next two chapters, we consider random polynomials whose zeros are chosen IID using some distribution. The second chapter answers questions regarding the asymptotic distribution of the critical points of a random polynomial whose zeros are IID on a circle on the complex plane. The fourth chapter describes the asymptotic behavior of the coefficients of a random polynomial whose zeros are IID Rademacher random variables. In the third chapter, we consider a random entire function that vanishes at a Poisson point process of intensity 1 on R. We give results on the asymptotic behavior of the coefficients as well as the resulting zero set on repeatedly differentiating this function
Biochar for the Control of Plant Pathogens
Biochar, the solid product of pyrolysis of biomass at thermal degradation temperatures, is useful in agriculture as manure for enhancing plant growth through the supply of nutrients. It is used in protected cultivation practices of vegetables and flower crops in the pot culture and grow bags especially to improve soil physicochemical properties, and in hydroponics to remove pollutants like heavy metals in the water. The usage of biochar as a potential soil amendment for plant growth promotion, improving soil fertility and plant disease suppression are being explored in recent years. Biochar made from many of the agro waste materials was found to suppress the plant pathogens in the soil and also effective in controlling the pathogens affecting aerial parts of the plants. Although direct antifungal or antibacterial effects and metabolites of biochar are poorly understood, induced systemic resistance in plants through signal transduction and expression of defence chemicals and metabolites have been studied. In addition, microbiome analyses through metagenome sequencing revealed an increase in the population of beneficial microbes (antagonistic to plant pathogens) in the rhizosphere soils applied with biochar
Proliposome and Prosurfactosome Formulations for Pulmonary Drug Delivery
This study aims to compare the efficiency of conventional liposomes and surfactant-enriched vesicles (surfactosomes) using the hydrophilic drug salbutamol sulphate (SBS) and the hydrophobic drug beclometasone dipropionate (BDP) for pulmonary delivery via nebulisation.
Initially liposomes and surfactosomes with or without cholesterol were prepared using thin film method and were compared for their VMD, span and drug entrapment. Their drug retention on extrusion through 5µm, 2µm, 1µm and 0.4µm polycarbonate membrane using mini-extruder was also studied. It was observed that liposomes were more stable than surfactosome.
Particulate based proliposome technology was also used to study their potential for generating stable and inhalable dispersions. Mannitol was used as the carbohydrate carrier and on hydration; proliposomes and prosurfactosomes have generated liposomes and surfactosomes respectively. The VMD, span and zeta potential of the vesicles, and drug entrapment and drug retention on extrusion were studied. It was seen that lower proportions of SBS were entrapped using proliposome technology; hence, further extrusions through 5µm and 2µm were avoided. In vesicle with BDP, inclusion of cholesterol has decreased the drug entrapment and crystallisation of mannitol was observed.
Nebulisation of liposomes and surfactosomes with and without cholesterol was studied using PARI LC sprint air jet nebuliser, Aeroneb pro and Beurer iH50 vibrating mesh nebulisers. Two stage (Twin) impinger was used to study the potential suitability of the generated vesicles for inhalation. VMD, span and zeta potential of vesicles before and after nebulisation was studied. BDP delivery and retention in both stages of the twin impinger was also studied. It was found that surfactosomes without cholesterol delivered maximum BDP to the twin impinger. Nebulisers suitable for all four formulations were also studied. Beurer iH50 delivered maximum BDP via liposomes with and without cholesterol, Aeroneb Pro delivered maximum BDP via surfactosomes with cholesterol to upper impinger while PARI LC sprint delivered maximum BDP via surfactosomes with cholesterol. VMD and span of aerosols generated from all three nebulisers were also studied.
Stability of liposomes and surfactosomes prepared using proliposome technology was studied. VMD, span, zeta potential and BDP retention before and after spray drying and freeze drying were investigated. It was concluded that liposomes and surfactosomes were equally stable when spray drying was used whereas liposomes were more stable that surfactosomes when freeze drying was conducted. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to analyse the characteristics of proliposomes and prosurfactosomes. A reduction in size and crystallinity was observed after spray drying and freeze drying of the formulations. Stability was also studied on storing proliposome and prosurfactosome in different environmental conditions like 5-6°C, room temperature and 40°C for a period of 3 months. It was concluded that both proliposomes and surfactosomes were most stable in 2-8°Cwhereas least stable in 40°C. Proliposomes were more stable than prosurfactosomes regardless of the storage temperature.
Formulation and characterisation of novel prosurfactosomes and comparing it with conventional liposomes for pulmonary drug delivery is the novelty of this thesis
Implementing a Humanitarian Needs Assessment Framework for Early Childhood Development: Informing Intervention Design for Displaced Rohingya Communities in Bangladesh
Recent literature focused on education in conflict-affected settings firmly establishes the link between early childhood interventions, poverty reduction, and the effects of adverse childhood experiences, particularly for those exposed to violent conflict. A key factor of effective interventions targeting young children and their families, and thus the long-term sustainability of behavior change, is how those interventions are received by local populations. Despite the importance of understanding local perspectives, needs assessments are often deprioritized when the focus is on meeting the immediate need for safety, food, water, and shelter. In the absence of a needs assessment, programming is developed without understanding the key priorities and motivations of the communities served. Given that the average length of protracted refugee situations is now more than 20 years, early childhood development programming designed without local perspectives brings with it the possibility of long-term repercussions, little community buy-in, and, consequently, limited to no impact. Therefore, the long-term costs of not doing needs assessments in humanitarian contexts are likely to far exceed the initial investments in conducting such research. In acknowledgment of these opportunities and constraints, this article presents a framework for conducting a needs assessment in a humanitarian setting, along with illustrative findings that underscore the value of seeking greater understanding of a community before designing early childhood development programming. Using a needs assessment to inform the design of an early childhood development intervention for displaced Rohingya communities living in Bangladesh, this article uses the design of that assessment to provide a framework for operationalizing needs assessments in humanitarian settings
Proliposome Tablets Manufactured Using A Slurry-Driven Lipid-Enriched Powders: Development, Characterization and Stability Evaluation
Proliposome powders were prepared via a slurry method using sorbitol or D-mannitol as carbohydrate carriers in 1:10 or 1:15 w/w lipid phase to carrier ratios. Soya phosphatidylcholine (SPC) and cholesterol were employed as a lipid phase and Beclometasone dipropionate (BDP) was incorporated as a model drug. Direct compaction using a Minipress was applied on the lipid-enriched powder in order to manufacture proliposome tablets. Sorbitol-based proliposome tablets in a 1:15 w/w ratio were found to be the best formulation as it exhibited excellent powder flowability with an angle of repose of 25.62 ± 1.08°, and when compacted the resultant tablets had low friability (0.20 ± 0.03%), appropriate hardness (crushing strength) (120.67 ± 12.04 N), short disintegration time (5.85 ± 0.66 min), and appropriate weight uniformity. Moreover, upon hydration into liposomes, the entrapment efficiency for sorbitol formulations in both 1:10 and 1:15 lipid to carrier ratios were significantly higher (53.82 ± 6.42% and 57.43 ± 9.12%) than D-mannitol formulations (39.90 ± 4.30% and 35.22 ± 6.50%), respectively. Extended stability testing was conducted for 18 months, at three different temperature conditions (Fridge Temperature (FT; 6°C), Room Temperature (RT; 22°C) and High Temperature (HT; 40°C)) for sorbitol-based proliposome tablets (1:15 w/w ratio). Volume median diameter (VMD) and zeta potential significantly changed from 5.90 ± 0.70 µm to 14.79 ± 0.79 µm and from -3.08 ± 0.26 mV to -11.97 ± 0.26 mV respectively at month 18, when samples were stored under HT conditions. Moreover, the entrapment efficiency of BDP decreased from 57.43 ± 9.12% to 17.93 ± 5.37% following 18 months storage under HT conditions. Overall, in this study for the first time, proliposome tablets were manufactured and thoroughly characterized, and sorbitol showed to be a promising carrier. [Abstract copyright: Copyright © 2017. Published by Elsevier B.V.
The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019
Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe
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Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
Implementing a Humanitarian Needs Assessment Framework for Early Childhood Development: Informing Intervention Design for Displaced Rohingya Communities in Bangladesh
تؤكد الكتابات الحديثة التي تركز على موضوع التعليم في البيئات المتضررة من النزاعات على العلاقة بين التدخلات في مرحلة الطفولة المبكرة والحد من الفقر وتأثيرات التجارب السلبية في مرحلة الطفولة، لاسيما لأولئك الذين تعرضوا لنزاع عنيف. من العوامل المهمة في التدخلات الفعالة التي تستهدف الأطفال الصغار وأُسَرِهِم، ومن ثم، استدامة التغيير السلوكي على الأجل البعيد، كيفية تلقي المجتمعات المحلية لتلك التدخلات. رغم أهمية استيعاب الاعتبارات المحلية، فإن عمليات تقييم الاحتياجات عادة ما تتراجع في الأولوية عندما يكون الاهتمام منصبًا على تلبية الاحتياج المُلِح للأمن والغذاء والماء والمأوى. إن عملية إعداد البرامج في ظل عدم وجود تقييم للاحتياجات تتم دون فهم لأهم أولويات ومحفزات المجتمعات التي تتم خدمتها. إن برامج تنمية الطفولة المبكرة التي تُصمم دون مراعاة للاعتبارات المحلية تحمل في طياتها تداعيات طويلة الأجل والعزوف من جانب المجتمع؛ ومن ثم، يكون تأثيرها محدودًا إلى منعدم، وذلك بعد أن أصبح متوسط حالات اللجوء طويل الأمد الآن يتجاوز 20 سنة؛ لهذا، فمن المرجح أن تتجاوز تكاليف عدم تقييم الاحتياجات في السياقات الإنسانية في الأجل البعيد قيمة الاستثمارات المبدئية التي تُوجَّه إلى إجراء تلك البحوث. اعترافًا بهذه الفرص والقيود، يقدم هذا المقال إطارًا لإجراء عمليات تقييم الاحتياجات في السياق الإنساني، فضلاً عن نتائج توضيحية تبرز قيمة الوقوف على فهم أكبر للمجتمع قبل الشروع في تصميم برامج تنمية الطفولة المبكرة. يستعين هذا المقال بتقييم الاحتياجات بغرض توفير المعلومات اللازمة لتصميم تدخل تنمية الطفولة المبكرة، ويُستَخدَم تصميم ذلك التقييم في تقديم إطار يجعل عمليات تقييم الاحتياجات في السياق الإنساني قابلة للتنفيذ
ملاحظة ميدانية: تطبيق إطار تقييم الاحتياجات الإنسانية بغرض تنمية الطفولة المبكرة: توفير المعلومات اللازمة لتصميم التدخل لمجتمعات الروهينغيا النازحة في بنغلاديش
تؤكد الكتابات الحديثة التي تركز على موضوع التعليم في البيئات المتضررة من النزاعات على العلاقة بين التدخلات في مرحلة الطفولة المبكرة والحد من الفقر وتأثيرات التجارب السلبية في مرحلة الطفولة، لاسيما لأولئك الذين تعرضوا لنزاع عنيف. من العوامل المهمة في التدخلات الفعالة التي تستهدف الأطفال الصغار وأُسَرِهِم، ومن ثم، استدامة التغيير السلوكي على الأجل البعيد، كيفية تلقي المجتمعات المحلية لتلك التدخلات. رغم أهمية استيعاب الاعتبارات المحلية، فإن عمليات تقييم الاحتياجات عادة ما تتراجع في الأولوية عندما يكون الاهتمام منصبًا على تلبية الاحتياج المُلِح للأمن والغذاء والماء والمأوى. إن عملية إعداد البرامج في ظل عدم وجود تقييم للاحتياجات تتم دون فهم لأهم أولويات ومحفزات المجتمعات التي تتم خدمتها. إن برامج تنمية الطفولة المبكرة التي تُصمم دون مراعاة للاعتبارات المحلية تحمل في طياتها تداعيات طويلة الأجل والعزوف من جانب المجتمع؛ ومن ثم، يكون تأثيرها محدودًا إلى منعدم، وذلك بعد أن أصبح متوسط حالات اللجوء طويل الأمد الآن يتجاوز 20 سنة؛ لهذا، فمن المرجح أن تتجاوز تكاليف عدم تقييم الاحتياجات في السياقات الإنسانية في الأجل البعيد قيمة الاستثمارات المبدئية التي تُوجَّه إلى إجراء تلك البحوث. اعترافًا بهذه الفرص والقيود، يقدم هذا المقال إطارًا لإجراء عمليات تقييم الاحتياجات في السياق الإنساني، فضلاً عن نتائج توضيحية تبرز قيمة الوقوف على فهم أكبر للمجتمع قبل الشروع في تصميم برامج تنمية الطفولة المبكرة. يستعين هذا المقال بتقييم الاحتياجات بغرض توفير المعلومات اللازمة لتصميم تدخل تنمية الطفولة المبكرة، ويُستَخدَم تصميم ذلك التقييم في تقديم إطار يجعل عمليات تقييم الاحتياجات في السياق الإنساني قابلة للتنفيذ