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Aquaculture and Horticulture Linkages with Dietary Diversity in Children 6-23 Months of Age.
No full textThis poster shows the linkages between aquaculture and Horticulture with dietary diversity in children
Barriers of Continuation of Growth Monitoring in Bara District.
No full textThis poster highlights the barriers of continuation of growth monitoring in bara district
A CMOS Luminescence Sensor for Intensity and Lifetime Dual Sensing
No full textAbstract: Luminescence is an important phenomenon in nature used extensively in biology, life sciences, biomedical and environmental applications. It is the light emitted by a substance not resulting from heat after absorbing a certain amount of excitation energy. Measurements of luminescence could involve measuring its intensity or measuring its lifetime. Sensing based on luminescence intensity suffers from the variation of many factors such as the optical path, excitation light intensity and the concentration of luminescent indicator used. Instead, sensing using luminescence lifetime is more reliable as it is immune to these factors. Both luminescence intensity and lifetime detection techniques can be applied to luminescence-based optical sensors since the emission intensity and lifetime of the luminescent indicator varies as a function of the concentration of a certain substance in the environment. In this dissertation, we propose a CMOS (complementary metal-oxide-semiconductor) sensor that combines both luminescence intensity and lifetime detection on a single chip. It applies multi-cycle charge modulation for lifetime extraction realized by capacitive transimpedance amplifier (CTIA) based circuitry. The designed in-pixel CTIA-based structure is able to capture the weak luminescence-induced voltage signal by accumulating photon-generated charges in 25 discrete gated 10ms time windows and 10us pulse width. A pinned photodiode on chip with 1.04pA dark current is utilized for luminescence detection. The proposed CTIA-based circuitry can achieve 2.1 mV/(nW/cm2) responsivity and 4.38 nW/cm2 resolution at 630 nm wavelength for intensity measurement and 45 ns resolution for lifetime measurement. The sensor chip is employed for measuring time constants and luminescence lifetimes of an InGaN-based white LED at different wavelengths. In addition, we demonstrate accurate measurement of the lifetime of an oxygen sensitive chromophore with sensitivity to oxygen concentration of 7.5%/ppm and 6%/ppm in both intensity and lifetime domain. This CMOS enabled oxygen sensor was then employed to test water quality from different sources (tap water, lakes, and rivers). However this sensor required an external analog to digital converter and, its operation was restricted to a dark room due to the sensor saturation caused by ambient light. In order to solve these issues, an improved CMOS image sensor for luminescence imaging was also designed. In addition to the combined intensity and lifetime sensing feature, this new image sensor converts the integrated output voltage into digital pulses. Ambient light compensation is also realized with an on-chip charge-pump based compensation circuitry. Driven by a 10 KHz clock signal with 20 us pulse width as the integration time window, the proposed circuitry can achieve 93 Hz/(uW/cm2) responsivity and 19nW/cm2 resolution at 575 nm. 2D luminescence images of a white LED are obtained with this proposed image sensor. Since common luminophores may exhibit different lifetimes one can use lifetime as a means of discriminating them. This enables the paradigm of "filterless" imaging. We verify this hypothesis for filter-less imaging for two fluorescent samples with similar emission wavelength ([Ru(dpp)3Cl2] and [Ru(bpy)3Cl2]) but different lifetimes. According to the measurement results, the proposed image sensor can easily distinguish two fluorescent indicators. Benefiting from this feature, in addition to the dual sensing of fluorescence intensity and lifetime, the proposed CMOS image sensor has the potential to be used in fluorescence imaging systems applying multiple fluorescent indicators without selective optical filters.Thesis (Ph.D.)--Tufts University, 2018.Submitted to the Dept. of Electrical Engineering.Advisor: Sameer Sonkusale.Keyword: Electrical engineering
The Origin of Physiological and Functional Brain Abnormalities During Fear Conditioning in Identical Twins Discordant for PTSD and Trauma Exposure
No full textAbstract: Psychophysiological and neuroimaging research has demonstrated impaired fear conditioning responses in PTSD. However, the origin of these biological abnormalities has not yet been identified. The purpose of this study was to determine whether these psychophysiological and neural abnormalities in PTSD are familial vulnerability factors, effects of trauma exposure, or are acquired characteristics of PTSD. In this case-control twin study, monozygotic twin pairs discordant for combat exposure completed a fear conditioning and extinction paradigm. Skin conductance responses (SCR) and brain activation during the task were measured. Results indicate that a decreased ability to distinguish between safety and threat cues, as indicated by SCR, and increased activation in the left and right insula during early trials of conditioning may be familial vulnerability factors of PTSD. The origin of these abnormalities has potential clinical implications for primary and/or secondary prevention of PTSD.Thesis (M.S.)--Tufts University, 2018.Submitted to the Dept. of Psychology.Advisor: Lisa Shin.Committee: Joseph DeBold, and Marie-France Marin.Keywords: Clinical psychology, Cognitive psychology, and Behavioral sciences
Social Networks and the Role of Norms in Missile Nonproliferation Policy Decisions
No full textAbstract: This dissertation addresses the question of whether norms can influence states' decisions on missile nonproliferation policies. It investigates specifically why South Korea, which continued to face an existential threat and moreover anticipated relying on a robust missile capability to address this threat, acceded to the Missile Technology Control Regime (MTCR)—a decision that very well could have limited, and in fact did limit, South Korea's future missile development. During the same time period (1994-2000), Egypt, which had normalized relations with its erstwhile principal security threat and moreover decided that long-range missiles would not be a central component to its overall military posture, decided that it would not join the MTCR. From a security perspective, these decisions appear not to be explained very well by neorealism, and, from an economic interdependence and international institutionalist perspective, also not very well addressed by neoliberalism. Could these decisions, then, be explained partially by norms-driven influences? This study employed multiple theoretic frameworks and research methodologies to answer this question. The analytic framework includes the rationalism-informed neorealist and neoliberal theories, and the constructivist research program. Qualitative analysis (process tracing) was used to compare insights across these three major research programs in international relations. Where the examination into norms could not be informed empirically by constructivism, the research design expanded into social psychology for insights into socialization mechanisms. This research also incorporated insights from social-networks theory, for perspectives on probabilistic formations of social-reference groups and quantified levels of relative influence of the members therein. Beginning with an original mapping of states' shared memberships in intergovernmental organizations, where states can interact socially and politically, and where social structures can develop, this research identified individual members of South Korea's and Egypt's respective per annum and, by extension, core social-reference groups. The result of this combined approach to the study of norms is a novel framework of indicators for where norms are operating and potentially are affecting preferences and behaviors. Further original contributions come from the specific identification of social-reference groups, their members, and those members' relative levels of potential influence. The key findings are that neorealism and neoliberalism, contrary to the initial impressions above, possess respectable explanatory power, with evidence that both South Korea and Egypt acted according to their genuine beliefs on the attendant costs and benefits of MTCR membership and on whether they would maximize their utility of finite resources in their pursuit of self-interest—for example, of enhanced security and economic benefits. However, both South Korea and Egypt were influenced in their respective decisions on MTCR membership also by norms, both intrinsically and insofar as norms can undergird social structures, general attitudes, and specific preferences that all can shape behavior. Specifically, South Korea was socialized and acculturated to be generally supportive of MTCR-related norms, while Egypt was influenced normatively in the opposite direction.Thesis (Ph.D.)--Tufts University, 2018.Submitted to the Dept. of Diplomacy, History, and Politics.Advisor: Robert Pfaltzgraff, Jr..Committee: Ian Johnstone, and Christopher Tunnard.Keywords: International relations, and Social psychology
Detangling PPI networks to uncover functionally meaningful clusters.
No full textBackground: Decomposing a protein-protein interaction network (PPI network) into non-overlapping clusters or communities, sometimes called "network modules," is an important way to explore functional roles of sets of genes. When the method to accomplish this decomposition is solely based on purely graph-theoretic measures of the interconnection structure of the network, this is often called unsupervised clustering or community detection. In this study, we compare unsupervised computational methods for decomposing a PPI network into non-overlapping modules. A method is preferred if it results in a large proportion of nodes being assigned to functionally meaningful modules, as measured by functional enrichment over terms from the Gene Ontology (GO).Keywords: PPI networks, Protein function prediction, Community detection, Diffusion state distance.Springer Open
On rhythms in neuronal networks with recurrent excitation.
No full textWe investigate rhythms in networks of neurons with recurrent excitation, that is, with excitatory cells exciting each other. Recurrent excitation can sustain activity even when the cells in the network are driven below threshold, too weak to fire on their own. This sort of "reverberating" activity is often thought to be the basis of working memory. Recurrent excitation can also lead to "runaway" transitions, sudden transitions to highfrequency firing; this may be related to epileptic seizures. Not all fundamental questions about these phenomena have been answered with clarity in the literature. We focus on three questions here: (1) How much recurrent excitation is needed to sustain reverberating activity?How does the answer depend on parameters? (2) Is there a positive minimum frequency of reverberating activity, a positive "onset frequency"?How does it depend on parameters? (3) When do runaway transitions occur? For reduced models, we givemathematical answers to these questions. We also examine computationally to which extent our findings are reflected in the behavior of biophysically more realistic model networks. Our main results can be summarized as follows. (1) Reverberating activity can be fueled by extremely weak slow recurrent excitation, but only by sufficiently strong fast recurrent excitation. (2) The onset of reverberating activity, as recurrent excitation is strengthened or external drive is raised, occurs at a positive frequency. It is faster when the external drive is weaker (and the recurrent excitation stronger) It is slower when the recurrent excitation has a longer decay time constant. (3) Runaway transitions occur onlywith fast, not with slow, recurrent excitation. We also demonstrate that the relation between reverberating activity fueled by recurrent excitation and runaway transitions can be visualized in an instructive way by a (generalized) cusp catastrophe surface
Education and micronutrient deficiencies: an ecological study exploring interactions between women's schooling and children's micronutrient status.
No full textBackground: Formal education can be a nutrition-sensitive intervention that supports the scale-up and impact of nutrition-specific actions. Maternal education has long been linked to child survival, growth, and development while adult earnings and nutrition are tied to years in school as a child. However, less is known about the relationship between maternal education and the micronutrient status of children, women and the general population.Keywords: Nutrition, Women's education, Maternal education, Micronutrients, Micronutrient deficiencies, Economic development, Anemia, Vitamin A, Zinc, Iodine.Springer Open
Water, sanitation, and hygiene access in southern Syria: analysis of survey data and recommendations for response.
No full textBackground: Water, sanitation, and hygiene (WASH) are immediate priorities for human survival and dignity in emergencies. In 2010, > 90% of Syrians had access to improved drinking water. In 2011, armed conflict began and currently 12 million people need WASH services. We analyzed data collected in southern Syria to identify effective WASH response activities for this context.Keywords: Emergency response, Water supply, Hygiene, Sanitation, Syria, Water safety plan.Springer Open
Integrating student feedback during "Dental Curriculum Hack-A-thon".
No full textBackground: The future of dental education is at crossroads. This study used the parameter of the 2016 Dental Curriculum Hack-a-Thon to assess intra- and inter-institutional agreement between student and faculty views regarding dental curriculums to determine if there is an impact in student perceptions towards dental education from before and after the event.Keywords: Dental education, Curriculum innovation, Student preferences.Springer Open