251 research outputs found
First person – Shweta Yadav
No full textABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Shweta Yadav is the first author on ‘RDGBα localization and function at membrane contact sites is regulated by FFAT–VAP interactions’, published in Journal of Cell Science. Shweta is a post-doctoral associate in the laboratory of Prof. Juan Botas at Baylor College of Medicine, Texas, USA, investigating neurodegenerative diseases.</jats:p
The social correlates of value consensus
No full textThis paper examines societal value consensus, or the extent to which individuals within a culture share similar values. This topic has been extensively theoretically discussed, but has received limited empirical attention. This paper explores the social variables of economic equality, religiosity and religious homogeneity and their relation to value consensus. Publicly available data from the latest wave of World Values Survey (N = 73,256), CIA world factbook and the World Bank World Development Indicators are used for analysis. Results reveal that value consensus is not correlated with religiosity, religious homogeneity or economic equality. Implications of these findings, with specific reference to economic developmental theories are discussed.M.A.Includes bibliographical referencesby Shweta A. Kulkarn
Adaptive geolocation based interference control for hierarchical cellular network with femtocells
No full textThis thesis presents adaptive interference control methods to mitigate undesirable interference effects from femtocells to macrocell users in hierarchical cellular networks. The study in this thesis begins by quantifying the deterioration in performance experienced by macrocell users on the downlink in a simulated 3G/CDMA environment. Our baseline results show that the median deterioration in signal-to-interference plus noise ratio (SINR) observed for the macrocell users may be up to 10dB and the outage probability increases by large extend. In the next part of study, we propose interference mitigation schemes - ‘Proximity Based Iterative’ (PBI) scheme and ‘Adaptive Interference Scaling’ (AIS) scheme to adjust femtocell power to reduce femtocell interference effect on macrocell users. We show that previously studied mechanisms like the load-spillage, utility based power adaptation usually require relatively high system overhead due to over-the-air signalling for estimation of interference. Proposed PBI and AIS schemes avoid such over-the-air signalling and make use of geo-location information and backhaul signalling for the femtocell interference estimation. These schemes achieve power re-distribution by scaling power uniformly across femtocells, while allowing the network operators to set desired target data rates. Results from simulations show that the PBI and AIS schemes are able to increase the number of macrocell users achieving chosen target data rates by up to 158% when compared with the value when femtocell transmission power is at maximum. However, in case of the PBI scheme, results shows that 25% of femtocell users may receive rates below the target rate. The AIS scheme provides an improvement over the PBI scheme by adjusting femtocell power according to the interference contribution by each femtocell. Thus, AIS achieves better performance and only up to 12:2% of femtocell users receive rates below the target rate. This study concludes with parametric evaluation of system throughput as a function of both macrocell and femtocell user densities. Qualitative results are provided to support the conclusion.M.S.Includes bibliographical referencesby Shweta Sagar
Roll-Call: an energy efficient radio frequency identification system.
No full textIn this thesis, we investigate two of the major challenges in pervasive systems: energy efficiency and co-existence of uncoordinated wireless messages by exploring the design of a Radio Frequency Identification (RFID) system intended to support the simultaneous and real time monitoring of thousands of entities. These entities, which may be individuals or inventory items, each carry a low-power transmit-only tag and are monitored by a collection of networked base-stations reporting to a central database. We have built a customized transmit-only tag with a small form-factor, and have implemented a real-time monitoring application intended to verify the presence of each tag in order to detect potential disappearance of a tag (perhaps due to item theft). Throughout the construction of our system, we have carefully engineered it for extended tag lifetime and reliable monitoring capabilities in the presence of packet collisions, while keeping the tags small and inexpensive.
The major challenge in this architecture (called Roll-Call) is to supply the energy needed for long range continuous tracking for a year or more of reporting once a second while keeping the tags (called PIPs) small and inexpensive. We have used this as a model problem for optimizing cost, size and lifetime across the entire pervasive, persistent system from firmware to protocol.M.S.Includes bibliographical references (p. 46-48)
Genomics of Complex Traits: Methods and Applications
No full textMy dissertation covers a number of studies that seek to understand the genetics and functional basis of complex traits in either human or animal models. The first project is a genetic study of bipolar disorder using exome sequencing, primarily involving variant burden analysis and pathway analysis. The second project uses gene expression as a functional readout of a tissue system, which allows us to identify aging signatures in the eye. These two studies represent complementary approaches; while the first reflects inheritance patterns of DNA variants and phenotypes, and the second is a functional readout of an organ system. In the next two studies, I use a rat model involving both genetics and genomic tools to perform an integrative search for genes and functional pathways implicated in metabolic phenotypes. In this collaborative study, I combine multiple datasets including genotype-based QTL mapping and gene expression based functional comparison, seeking to triangulate signals that may be noisy or subtle in one platform alone. Along the way, I had to develop methodologies for data integration, and worked on solidifying existing resources—in this case, the rat reference genome. Mine is the beginning of a consolidated effort by the rat-genomics community to arrive at a more complete and accurate reference genome, so that the community can build on this improved resource for more accurate research in the future. As my studies have involved both genome and exome sequencing data, one of the challenges is to identify not only single nucleotide variants but also larger scale DNA copy number changes. Despite the many tools for calling copy number changes, there is still confusion about the proper investment of resources based on a principled power analysis. In my last chapter, I develop a basic mathematical framework that incorporates most of the important practical parameters impacting power, and create an online calculator and examples of some usage cases. Taken together, this dissertation is a reflection of how the field of genetics and genomics has moved in the last few years, involving rapidly advancing technology, and datasets with complex structures, requiring careful exploration and method development.PhDBioinformaticsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/145925/1/sramdas_1.pd
Next-Generation Sequencing in Genetic Studies of Psychiatric Disorders
No full textNext-generation sequencing (NGS) technologies make it possible to efficiently detect DNA variants in either entire genomes or any subsets of the genome, and have dramatically enhanced our ability to search for genetic risk factors of complex psychiatric diseases. While genotyping-based association studies focus on common variants that track extended genomic segments, NGS provides unbiased identification of both common and rare variants, including those that are functionally important but appear in very few families or sporadic cases. Thus NGS directly highlights plausible causal variants, even if such variants are extremely heterogeneous in the population. Meanwhile, such heterogeneity requires new analytical approaches that can aggregate rare variant burden over predefined functional unit such as a gene or a segment of non-coding region with presumed function. Rapid application of NGS technologies also underscored other limits in psychiatric genetics research, including the need for detailed phenotyping and multi-scale integration of diverse data types.</p
Models and algorithms for spectrum coexistence in wireless networks
No full textIn the last decade, there have been several technological trends that have occurred together and have caused a shift in how wireless systems will be deployed. The significant increase in the capabilities of mobile devices, combined with the proliferation of Internet enabled services, and the improvement in the communication support provided by new waveforms for wireless communications, have initiated a shift from the traditional, macrocell-based cellular network to new forms of radio access technologies (RATs) involving multiple, smaller cells deployed in vicinity of each other. These small cells will often support diverse wireless technologies and be operated by different providers. The resulting heterogeneity, unfortunately, can lead to serious internetwork interference that can negate the improvement in overall system performance that was the original motivation for employing many small cells in close proximity. In this thesis, we examine different technologies that are needed for flexible spectrum management to support the coordination that is needed for coexistence between many small cell wireless networks. Motivated by the need for internetwork architectures that support spectrum coordination, we (1) conduct performance evaluation associated with the joint deployment of mobile and fixed hotspot networks, (2) develop spectrum models that characterize interference among different wireless entities, (3) provide new methods for efficient hardware emulation of wireless channels, (4) devise algorithms that estimate radio spectrum usage, and (5) provide algorithms for coordination between different wireless systems to improve the overall system performance and spectrum efficiency. The first part of the thesis investigates spectrum coexistence in wireless networks by exploring the underlying performance challenges that exist when mobile hotspots are deployed in an environment of densely deployed, static wireless access networks. Next part of thesis investigates design of hardware emulator of radio channels to accurately capture the effect of real-world wireless channels upon communications waveforms while minimizing computational complexity. Next, we explore a fundamental building block of spectrum management for supporting better utilization of radio spectrum which involves predicting the impact that an emitter will have at different geographic locations. We then examine various challenges associated with coordinating spectrum access between different wireless technologies by exploring the specific case of Wi-Fi and LTE coexistence in emerging unlicensed frequency bands. Finally, recognizing the broad challenges associated with addressing spectrum coexistence in emerging wireless systems, we identify several directions for future investigation and suggest different approaches for tackling these challenges.Ph.D.Includes bibliographical referencesby Shweta S. Sagar
Using freewriting to make sense of literature
No full textPeer reviewedPublished on The U.S. Department of State websit
ACQUISITIONS AND FOREIGN COMPETITION
No full textRights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Downloaded 18-Sep-2016 01:38:3
Using Freewriting to Make Sense of Literature
No full textPeer reviewedPublished on The U.S. Department of State websit
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