G337.342-0.119 (the "Pebble"): A Cold, Dense, High-Mass Molecular Cloud with Unusually Large Linewidths and a Candidate High-Mass Star Cluster Progenitor

Exactly how high-mass star clusters form, especially the young massive clusters (YMCs: age $10^4$ solar masses), remains an open problem, largely because they are so rare that examples of their cold, dense, molecuar progenitors remain elusive. The molecular cloud G337.342$-$0.119, the `Pebble,' is a candidate for such a cold progenitor. Although G337.342$-$0.119 was originally identified as four separate ATLASGAL clumps, the similarity in their molecular line velocities and linewidths in the MALT90 dataset demonstrate that these four clumps are in fact one single, coherent cloud. This cloud is unique in the MALT90 survey for its combination of both cold temperatures ($T_{dust} \sim 14$ K) and large linewidths $(\Delta V \sim 10$ km s$^{-1}$). The near/far kinematic distance ambiguity is difficult to resolve for G337.342$-$0.119. At the near kinematic distance (4.7 kpc), the mass is 5,000 solar masses and the size is $7\times2$ pc. At the far kinematic distance (11 kpc), the mass is 27,000 solar masses and the size is $15 \times 4$ pc. The unusually large linewidths of G337.342$-$0.119 are difficult to reconcile with a gravitationally bound system in equilibrium. If our current understanding of the Galaxy's Long Bar is approximately correct, G337.342$-$0.119 cannot be located at its end. Rather, it is associated with a large star-forming complex that contains multiple clumps with large linewidths. If G337.342$-$0.119 is a prototypical cold progenitor for a high-mass cluster, its properties may indicate that the onset of high-mass star cluster formation is dominated by extreme turbulence

Low prevalence of myocilin mutations in an African American population with primary open-angle glaucoma

Purpose Mutations in the myocilin gene (MYOC) are associated with primary open-angle glaucoma (POAG) in many different populations. This study represents the first large survey of MYOC mutations in an African American population. Methods: We recruited 529 African American subjects with POAG and 270 African American control subjects in this study. A complete eye examination and blood collection was performed in all study subjects. Genomic DNA was extracted. The entire coding sequence of MYOC was amplified and sequenced using the Sanger method. Identified MYOC variants were compared with previously reported MYOC mutations. Results: We identified a total of 29 MYOC variants including six potential MYOC mutations. Two mutations (Thr209Asn and Leu215Gln) are novel and are found only in cases and no controls. We also identified four previously reported MYOC mutations in cases and no controls (Tyr453MetfsX11, Gln368X, Thr377Met, and Ser393Arg). The overall frequency of glaucoma-causing MYOC mutations in our African American population with POAG was 1.4%. Conclusions: We identified two novel probable glaucoma-causing MYOC mutations (Thr209Asn and Leu215Gln). This study indicates that, despite the high prevalence of POAG, MYOC mutations are rare in the African American population

Landscape ecology of microbes in peatlands under different management regimes

Peatlands are essential ecosystems that play a significant role in the sequestration of carbon, water provisioning and global biodiversity. However, human activities are threatening their ability to sustain important ecosystem services. Soil microbial activity supports ecosystem processes in peatlands, but little is known about the main drivers of microbial community dynamics and their association with ecosystem functioning. Therefore, to better forecast the response of the microbiome to management regimes, a deeper understanding is required. The overall goal of this thesis is to identify the environmental drivers of peatland soil microbial communities and to investigate the effects of land management on community composition, function and resistance to habitat change. The study was based on the analysis of a pre-existing data set on microbial communities regarding land reclamation in Canada and on original data collection and analysis regarding burning regimes at Moor House Nature Reserve, UK. The Canadian data were used to determine how microbial communities and function change along three natural fens and a constructed fen in the Athabasca oil sands region of Alberta and assess the impact of this reclamation practice. The UK research focused on investigating how prescribed burning affects soil properties, microbial community structure and microbial N-cycling using a range of approaches including next-generation sequencing and qPCR. Overall, results show first, total substrate respiration was significantly higher in the constructed fen, yet, the diversity of fungi and prokaryotes was higher in the treed-rich fen and community composition was significantly different between fens. However, prokaryote community composition was similar in the constructed fen to the treed-rich fen showing a resilience of the community to soil transfer. Second, there were changes in archaeal, bacterial and fungal diversity and community composition between burn treatments and soil profiles. Fungal diversity showed a more drastic change across burn treatments throughout the soil profile and there was also a shift in the relative abundance of trophic modes. Co-occurrence network analysis revealed that the non-burn topsoil had a larger and more complex network structure with more positive links than those under rotational burns. Third, amoA-AOA, amoA-AOB and nifH were higher in the topsoil of the non-burn control while the abundance of nirK was higher in plots under short rotation and long rotation regimes. ChiA abundance was greater in plots under a short rotation burn regime and decreased with soil depth. This result suggests that microbial N turnover potential is affected by the practice of burning. The changes in microbial communities and function are anticipated to have an impact on important peatland ecosystem services

Development of proteomic techniques for biomarker discovery

The main aim of my research, presented here, is to develop proteomic research techniques, for their use in biomarker discovery and identification. This is broken down into three main chapters: • Biomarker Identification in Stroke Brain guided by MALDI-imaging. • Evaluation of the Effectiveness of Heat Treatment for Prevention of Proteomic Sample Degradation using Label Free Relative Quantitation. • Discovery and Identification of Biomarkers for Hypertension Within these chapters special attention is paid to sample preparation, development and assessment of new methods for biomarkers discovery and identification, the importance of experimental design and the application of relevant and useful statistical methods to enable the mining of useful information from rich datasets. The biological changes in stroke induced mouse brain tissue are studied, the prevention of degradation to tissue samples by a novel heat treatment method and changes to plasma samples from hypertensive, wild type and a congenic strain of rat are also studied. The outcomes of this work are multiple, namely: • The identification of a possible marker for stroke from mouse brain tissue • The effect of a new heat treatment device on proteomic data obtained from mouse brain tissue • The novel application of a statistical analysis to a new type of dataset (LC-MS and label free quantitation of biological samples) • The identification of possible biomarkers for hypertension in rat plasma using this metho

Set-Rationalizable Choice and Self-Stability

A common assumption in modern microeconomic theory is that choice should be rationalizable via a binary preference relation, which \citeauthor{Sen71a} showed to be equivalent to two consistency conditions, namely $\alpha$ (contraction) and $\gamma$ (expansion). Within the context of \emph{social} choice, however, rationalizability and similar notions of consistency have proved to be highly problematic, as witnessed by a range of impossibility results, among which Arrow's is the most prominent. Since choice functions select \emph{sets} of alternatives rather than single alternatives, we propose to rationalize choice functions by preference relations over sets (set-rationalizability). We also introduce two consistency conditions, $\hat\alpha$ and $\hat\gamma$, which are defined in analogy to $\alpha$ and $\gamma$, and find that a choice function is set-rationalizable if and only if it satisfies $\hat\alpha$. Moreover, a choice function satisfies $\hat\alpha$ and $\hat\gamma$ if and only if it is \emph{self-stable}, a new concept based on earlier work by \citeauthor{Dutt88a}. The class of self-stable social choice functions contains a number of appealing Condorcet extensions such as the minimal covering set and the essential set.Comment: 20 pages, 2 figure, changed conten

Wee Folk, Good Folk

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Alien Registration- Allingham, Gertrude M. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/21286/thumbnail.jp