43 research outputs found
Deletion of the last two exons of FGF10 in a family with LADD syndrome and pulmonary acinar hypoplasia
No full textObstacles, slopes and tic-tac-toe: an excursion in discrete geometry and combinatorial game theory
No full textThe minimum number of slopes used in a straight-line drawing of G is called the slope number of G. We show that every cubic graph can be drawn in the plane with straight line edges using only the four basic slopes {0, π/4, π/2,−π/4}. We also prove that four slopes have this property if and only if we can draw K4 with them. Given a graph G, an obstacle representation of G is a set of points in the plane representing the vertices of G, together with a set of obstacles (connected polygons)
such that two vertices of G are joined by an edge if and only if the corresponding points can be connected by a segment which avoids all obstacles. The obstacle number of G is the minimum number of obstacles in an obstacle representation of G. We show that there are graphs on n vertices with obstacle number (n/log n). We show that there is an m = 2n + o(n), such that, in the Maker-Breaker game played on Zd where Maker needs to put at least m of his marks consecutively in one
of n given winning directions, Breaker can force a draw using a pairing strategy. This improves the result of Kruczek and Sundberg who showed that such a pairing strategy exits if m ≥ 3n. A simple argument shows that m has to be at least 2n+1 if Breaker is only allowed to use a pairing strategy, thus the main term of our bound is optimal.Ph. D.Includes bibliographical referencesIncludes vitaby V S Padmini Mukkamal
Risk management through social networks among male and female pastoralists in Karamoja, Uganda
No full textEnvironmental volatility, resource-related risks, and the overall uncertainty about the future fundamentally shape behavioral strategies and are critical to understanding the evolution of human social behavior. One of the central ways in which humans in subsistence economies manage risk and uncertainty is through pooling or sharing risk with other individuals, such as central place food sharing among forager populations. Among pastoralists in East Africa, risk pooling takes the form of ‘stock friendships’: an informal insurance system in which male herders form mutually beneficial partnerships through livestock transfers. Networks of stock friends are critical to recouping short term losses such as food shortage, as well as to ensuring long-term sustainability through the rebuilding of herds. This dissertation investigates risk pooling friendships and other risk management strategies of pastoralists in Karamoja, Uganda. Risk management is a central concern for pastoralists in Karamoja because of the unreliable climate, recent volatile history, and lack of institutional support. Consequently, social networks of livestock and food exchange, such as stock friendships, play a significant role in minimizing the adverse effects of disasters. During fourteen months of fieldwork, I collected qualitative and quantitative data on men’s stock friendship networks, women’s close friendship networks, and individuals’ exchange networks during a prolonged drought. I use these data to present the following: 1) an ethnographic investigation of friendship contracts among men and women; 2) an examination of the characteristics of friendship networks, including size, composition, geographical spread, and relational content; 3) a study of how individual level and external factors influence friendship networks; and 4) an analysis of which social exchange networks are activated during drought induced stress. Based on data on norms and transfers within friendship networks, I argue that risk pooling friendships in Karamoja are characterized by needbased transfers and ‘demand sharing’ rather than account-keeping reciprocity. Further, I show that during periods of extreme stress, need-based transfers of food, livestock, and money are acquired not only from kin and friendship networks (‘strong ties’), but also from ‘weak tie’ friends within the neighborhood. I, thus, contend that engaging in risk pooling relationships and need based transfers are a necessity in an environment characterized by unpredictability. Lastly, I present results from an experimental economic game that explores participants’ risk attitudes and time preference—variables critical to understanding decision-making under conditions of chronic risk and uncertainty.Ph.D.Includes bibliographical referencesby K. Padmini Iye
SLC2A9 and Hyperuricemia: A Locus-Wide Association Study To Identify Population-Specific Genetic Variants In New Zealand Māori and Pacific People
No full textHyperuricemia, pathologically defined as the presence of an elevated level of serum urate, is a prerequisite for gouty arthritis. The solute carrier family 2 member 9 (SLC2A9) gene that encodes a urate transporter tops the list of hyperuricemic genes. It is a key genetic determinant of serum urate levels and explains about 3% of urate variance. Gout is highly prevalent in the New Zealand Māori and other Polynesian populations. As an attempt to understand the reason for this increased prevalence, this study focused on the identification and characterisation of Polynesian-specific genetic variants within the SLC2A9 locus conferring susceptibility to hyperuricemia.
The SLC2A9 locus was resequenced in 809 individuals (Polynesian, n = 440 and European, n = 369) comprising hyperuricemic cases and normouricemic controls. All Polynesians were from New Zealand while Europeans were from New Zealand and the United States. Association analysis was carried out to identify variants within the SLC2A9 locus that confer risk for hyperuricemia. Multiple adjusted logistic regression analysis was carried out using R version 3.4.1. A number of data visualization techniques and variant annotation tools were used to interpret and represent data and variant annotations.
A total of 3963 variants was identified within the locus, of which 25 and 53 variants displayed nominal significance (p-value ≤ 0.05) with hyperuricemia in the East and West Polynesians, respectively. These significant signals were further analysed. Five variants were chosen for replication via genotyping (VAR_CHR4_9914056, rs373311989, VAR_CHR4_9452283, VAR_CHR4_10160679 and VAR_CHR4_10457448). The A allele of VAR_CHR4_9914056, located in intron 7 of the SLC2A9 gene, was found to be associated with hyperuricemia in the East Polynesians in the Discovery Cohort (adjusted OR = 28.30, POR = 0.003) and the association was successfully replicated in the larger independent Replication Cohort, although with a relatively smaller effect size (adjusted OR = 2.93, POR = 0.004).
The variants prioritized for replication were also tested for the association with gout in Polynesians. The A allele of the intergenic variant, VAR_CHR4_10160679, showed a significant protective association with gout both during discovery (adjusted OR = 0.04, POR = 0.03) and replication (adjusted OR = 0.32, POR = 0.01) in West Polynesians. The region containing this variant (4:10120364 – 4:10494666) displayed variation in the haplotype structure in Polynesians compared to Europeans, as revealed by haplotype analysis and visualization.
This research was conducted to provide a greater insight into the genetic causes of gout and understand the reason for the higher prevalence of hyperuricemia in Polynesians. The work signifies the usefulness of targeted resequencing, especially in a bespoke fashion, in studying the genetic basis of a trait/disease that is highly prevalent in a particular population and further evinces the association of non-coding variants in the SLC2A9 locus, mapping to the human 4p16.1 chromosomal region, with hyperuricemia and gout in Polynesians. The study also demonstrates the utility of data visualization tools and techniques in exploratory big data analysis. The identification of the Polynesian-specific hyperuricemia-associated variant can be applied in precision medicine and public health genomics to improve health outcomes for the target population
A quantitative analysis of complexity of human pathogen-specific CD4 T cell responses in healthy M. tuberculosis infected South Africans
No full textAuthor Summary: Human pathogen-specific immune responses are tremendously complex and the techniques to study them ever expanding. There is an urgent need for a quantitative analysis and better understanding of pathogen-specific immune responses. Mycobacterium tuberculosis (Mtb) is one of the leading causes of mortality due to an infectious agent worldwide. Here, we were able to quantify the Mtb-specific response in healthy individuals with Mtb infection from South Africa. The response is highly diverse and 66 epitopes are required to capture 80% of the total reactivity. Our study also show that the majority of the identified epitopes are restricted by multiple HLA alleles. Thus, technical advances are required to capture and characterize the complete pathogen-specific response. This study demonstrates further that the approach combining identified epitopes into "megapools" allows capturing a large fraction of the total reactivity. This suggests that this technique is generally applicable to the characterization of immunity to other complex pathogens. Together, our data provide for the first time a quantitative analysis of the complex pathogen-specific T cell response and provide a new understanding of human infections in a natural infection setting
Urban Infrastructure Damage Detection and Mapping Using Sentinel 1
No full textNatural or man-made disasters can have a drastic impact on social, economic and environmental aspects of an affected population. Specifically, earthquakes are one of the most potent natural hazards, which cause a disproportionate amount of fatalities, primarily due to a) unexpected building collapses, b) restricted or limited access to basic amenities and c) potential hazards following earthquakes such as landslides, tsunamis etc. It is crucial to have an overview of the infrastructural damage caused following a disaster for search and rescue services to assess the extent of the damage. For the purpose of this research, Sentinel 1 imagery is used to map the building damage in an urban area after a disaster. A combination of parameters such as persistent scatterers, pixel amplitude and phase is used with a timeseries of full-resolution and spatially averaged radar images. Points that are stable in amplitude over a long timeseries, also known as Persistent Scatterers, are extracted from a stack of full-resolution images. The amplitudes of persistent scatterers, along with amplitude and coherence of pixels derived from a stack of spatially-averaged images, are statistically analysed to check the trends of the parameters pre- and post the disaster. A change detection algorithm is applied to this stack in order to localise the areas of building damage. The results are superimposed on Google Earth for easy interpretation using a graded damage scale. The analysis shows that exploiting the persistent scatterer amplitudes in the manner used in this research provides a novel way of locating building damage. This technique can be used effectively in urban areas. Using a combination of pixel amplitudes and coherence along with the persistent scatterers helps correctly find new and unique points of damage for each parameter used. The results were validated using reference Grading and crowd-sourced maps. The results illustrate that the proposed approach can be used for detecting and producing informative maps on infrastructural damage detection in urban areas
Speaking the Same Language: How Ethnonationalism and Hindutva Seep into the Adjudication of Citizenship in Assam
No full textIn the border state of Assam, questions of security, identity and citizenship have long shaped its politics. This essay focuses on the evolving jurisprudence of citizenship in the Indian border state of Assam. The author analyses 1,444 judgments of the Gauhati High Court, passed between 2013 and 2019, to study how courts interpret and enforce the laws of citizenship
