Heating experiments of the Tagish Lake meteorite: Investigation of the effects of short-term heating on chondritic organics

We present in this study the effects of short-term heating on organics in the Tagish Lake meteorite and how the difference in the heating conditions can modify the organic matter (OM) in a way that complicates the interpretation of a parent body’s heating extent with common cosmothermometers. The kinetics of short-term heating and its influence on the organic structure are not well understood, and any study of OM is further complicated by the complex alteration processes of the thermally metamorphosed carbonaceous chondrites—potential analogues of the target asteroid Ryugu of the Hayabusa2 mission—which had experienced posthydration, short-duration local heating. In an attempt to understand the effects of short-term heating on chondritic OM, we investigated the change in the OM contents of the experimentally heated Tagish Lake meteorite samples using Raman spectroscopy, scanning transmission X-ray microscopy utilizing X-ray absorption near edge structure spectroscopy, and ultraperformance liquid chromatography fluorescence detection and quadrupole time of flight hybrid mass spectrometry. Our experiment suggests that graphitization of OM did not take place despite the samples being heated to 900 °C for 96 h, as the OM maturity trend was influenced by the heating conditions, kinetics, and the nature of the OM precursor, such as the presence of abundant oxygenated moieties. Although both the intensity of the 1s σ* exciton cannot be used to accurately interpret the peak metamorphic temperature of the experimentally heated Tagish Lake sample, the Raman graphite band widths of the heated products significantly differ from that of chondritic OM modified by long-term internal heating

Essays on the performance of savings groups

This thesis consists of three chapters that each address a different factor that influences the performance of SGs. Chapter 1 investigates the effect of financial linkages on the performance of savings groups. Financial linkages occur when informal savings groups either open a joint savings account at a formal financial institution or participate in a joint credit facility arrangement with a formal financial institution. The central reason for financial linkages between savings groups and formal financial institutions is to balance group liquidity shortages and excesses. Additionally, financial linkage is attractive as it is viewed as a conduit for formal financial inclusion. Applying a difference-in-differences methodology to a matched sample of data on 3,234 savings groups from 31 countries, we investigate the differential effect of a savings and credit linkage. This is complemented with a qualitative investigation from SGs in Uganda that provides more insight into the observed results obtained from the quantitative investigation. Overall, there is a positive effect of savings linkage on savings per member and return on savings. We argue that this is due to the safekeeping function that an account with a formal financial institution provides. There is, however, a reduction in the fund utilization rate following a savings linkage, probably because the cash is no longer readily at hand in the lockbox but is now deposited in a bank that may be geographically located at a distance from the group and may also require procedures to withdraw it. By contrast, there is a negative effect of the credit linkage on savings per member and return on savings. This may be because infusion of external capital discourages internal savings mobilization. The results suggest that financial linkage should be demand-driven, i.e., based on the need of the SG, and savings group facilitators should weigh the costs against the benefits before prescribing financial linkages for SGs. Chapter 2 takes a critical look at the effectiveness of financial education delivered through the informal savings groups. There is widespread recognition that traditional classroom-based financial education has fallen short of stimulating substantial changes in adult financial behavior (e.g., Carpena, Cole, Shapiro, & Zia, 2019). We show that savings groups provide an innovative delivery channel for financial education especially at the bottom of the pyramid. Based on a matched sample of data on 2,364 savings groups from 9 African countries, our random effects regression results show the benefits of financial education both at the individual and at the group level. At the individual level, members increase their savings as evidenced by the increase in savings per member. At the group level, there is an increase in profitability and the rate at which members’ savings are converted into loans. This is evidenced by the increased fund utilization rate and return on savings for groups that receive financial education. We partly attribute this to the fact that savings groups offer members an immediate opportunity and framework for putting into practice the new financial knowledge acquired. The findings show that knowledge alone may not be enough to change individual financial behavior and should be complemented with practical hands-on experience as is possible in SGs. Chapter 3 delves into the composition of the group in terms of gender and how this influences the group’s profit-generating capacity. I start from the premise that, like many development efforts, the savings group was initially promoted as a gender-focused financial initiative with a particular emphasis on women. The first facilitated savings group, the Village Savings and Loan Association, was at its inception exclusively composed of women. Yet, recent trends suggest that male participation and advocacy to engage men as group members are increasing. I investigate the effect of male membership on the profit-generating capacity of savings groups and further probe the moderating effect of gender equality in the countries where the groups are located. Based on a sample of 81,853 savings groups from 30 countries, random effects regression results suggest that male membership negatively impacts the profit-generating capacity of savings groups. Moreover, gender inequality in a country strengthens the observed relationship. These findings highlight the need to thoroughly appraise gender-based interventions aimed at the SGs in order to avoid harming some aspects of their core operational model. Further, they also show that contextual factors should be accounted for before rolling out interventions.publishedVersio

Replication-Coupled PCNA Unloading by the Elg1 Complex Occurs Genome-wide and Requires Okazaki Fragment Ligation

Open Access funded by Medical Research Council Acknowledgments We thank Dr Anja Bielinsky for plasmids and Dr. M.K. Raghuraman for a cdc9-1 strain. Alexander Lorenz (University of Aberdeen) provided valuable comments on the manuscript. This work was supported by Biotechnology and Biological Sciences Research Council (BBSRC) grant BB/K006304/1 to A.D., Medical Research Council Career Development Fellowship MR/L019698/1 to T.K., and MEXT Grant-in-Aid for Scientific Research on Innovative Areas to K.S.Peer reviewedPublisher PD

Cgaln: fast and space-efficient whole-genome alignment

<p>Abstract</p> <p>Background</p> <p>Whole-genome sequence alignment is an essential process for extracting valuable information about the functions, evolution, and peculiarities of genomes under investigation. As available genomic sequence data accumulate rapidly, there is great demand for tools that can compare whole-genome sequences within practical amounts of time and space. However, most existing genomic alignment tools can treat sequences that are only a few Mb long at once, and no state-of-the-art alignment program can align large sequences such as mammalian genomes directly on a conventional standalone computer.</p> <p>Results</p> <p>We previously proposed the CGAT (Coarse-Grained AlignmenT) algorithm, which performs an alignment job in two steps: first at the block level and then at the nucleotide level. The former is "coarse-grained" alignment that can explore genomic rearrangements and reduce the sizes of the regions to be analyzed in the next step. The latter is detailed alignment within limited regions. In this paper, we present an update of the algorithm and the open-source program, Cgaln, that implements the algorithm. We compared the performance of Cgaln with those of other programs on whole genomic sequences of several bacteria and of some mammalian chromosome pairs. The results showed that Cgaln is several times faster and more memory-efficient than the best existing programs, while its sensitivity and accuracy are comparable to those of the best programs. Cgaln takes less than 13 hours to finish an alignment between the whole genomes of human and mouse in a single run on a conventional desktop computer with a single CPU and 2 GB memory.</p> <p>Conclusions</p> <p>Cgaln is not only fast and memory efficient but also effective in coping with genomic rearrangements. Our results show that Cgaln is very effective for comparison of large genomes, especially of intact chromosomal sequences. We believe that Cgaln provides novel viewpoint for reducing computational complexity and will contribute to various fields of genome science.</p