Nationalism and internationalism : an address before the Rotary Club of Shanghai, November 26, 1926

10 pageshttps://digitalrepository.trincoll.edu/moore/1061/thumbnail.jp

The a-number of hyperelliptic curves

It is known that for a smooth hyperelliptic curve to have a large $a$-number, the genus must be small relative to the characteristic of the field, $p>0$, over which the curve is defined. It was proven by Elkin that for a genus $g$ hyperelliptic curve $C$ to have $a_C=g-1$, the genus is bounded by $g<\frac{3p}{2}$. In this paper, we show that this bound can be lowered to $g <p$. The method of proof is to force the Cartier-Manin matrix to have rank one and examine what restrictions that places on the affine equation defining the hyperelliptic curve. We then use this bound to summarize what is known about the existence of such curves when $p=3,5$ and $7$.Comment: 7 pages. v2: revised and improved the proof of the main theorem based on suggestions from the referee. To appear in the proceedings volume of Women in Numbers Europe-

A human colonic crypt culture system to study regulation of stem cell-driven tissue renewal and physiological function

The intestinal epithelium is one of the most rapidly renewing tissues in the human body and fulfils vital physiological roles such as barrier function and transport of nutrients and fluid. Investigation of gut epithelial physiology in health and disease has been hampered by the lack of ex vivo models of the native human intestinal epithelium. Recently, remarkable progress has been made in defining intestinal stem cells and in generating intestinal organoid cultures. In parallel, we have developed a 3D culture system of the native human colonic epithelium that recapitulates the topological hierarchy of stem cell-driven tissue renewal and permits the physiological study of native polarized epithelial cells. Here we describe methods to establish 3D cultures of intact human colonic crypts and conduct real-time imaging of intestinal tissue renewal, cellular signalling, and physiological function, in conjunction with manipulation of gene expression by lentiviral or adenoviral transduction. Visualization of mRNA- and protein-expression patterns in cultured human colonic crypts, and cross-validation with crypts derived from fixed mucosal biopsies, is also described. Alongside studies using intestinal organoids, the near-native human colonic crypt culture model will help to bridge the gap that exists between investigation of colon cancer cell lines and/or animal (tissue) studies, and progression to clinical trials. To this end, the near native human colonic crypt model provides a platform to aid the development of novel strategies for the prevention of inflammatory bowel disease and cancer

Integrable Structure of 5d5d N=1\mathcal{N}=1 Supersymmetric Yang-Mills and Melting Crystal

We study loop operators of $5d$ $\mathcal{N}=1$ SYM in $\Omega$ background. For the case of U(1) theory, the generating function of correlation functions of the loop operators reproduces the partition function of melting crystal model with external potential. We argue the common integrable structure of $5d$ $\mathcal{N}=1$ SYM and melting crystal model.Comment: 12 pages, 1 figure, based on an invited talk presented at the international workshop "Progress of String Theory and Quantum Field Theory" (Osaka City University, December 7-10, 2007), to be published in the proceeding

The genetic structure of Aedes aegypti populations is driven by boat traffic in the Peruvian Amazon.

In the Americas, as in much of the rest of the world, the dengue virus vector Aedes aegypti is found in close association with human habitations, often leading to high population densities of mosquitoes in urban settings. In the Peruvian Amazon, this vector has been expanding to rural communities over the last 10-15 years, but to date, the population genetic structure of Ae. aegypti in this region has not been characterized. To investigate the relationship between Ae. aegypti gene flow and human transportation networks, we characterized mosquito population structure using a panel of 8 microsatellite markers and linked results to various potential mechanisms for long-distance dispersal. Adult and immature Ae. aegypti (&gt;20 individuals per site) were collected from Iquitos city and from six neighboring riverine communities, i.e., Nauta, Indiana, Mazan, Barrio Florida, Tamshiaco, and Aucayo. FST statistics indicate significant, but low to moderate differentiation for the majority of study site pairs. Population structure of Ae. aegypti is not correlated with the geographic distance between towns, suggesting that human transportation networks provide a reasonable explanation for the high levels of population mixing. Our results indicate that Ae. aegypti gene flow among sub-populations is greatest between locations with heavy boat traffic, such as Iquitos-Tamshiaco and Iquitos-Indiana-Mazan, and lowest between locations with little or no boat/road traffic between them such as Barrio Florida-Iquitos. Bayesian clustering analysis showed ancestral admixture among three genetic clusters; no single cluster was exclusive to any site. Our results are consistent with the hypothesis that human transportation networks, particularly riverways, are responsible for the geographic spread of Ae. aegypti in the Peruvian Amazon. Our findings are applicable to other regions of the world characterized by networks of urban islands connected by fluvial transport routes

Large Silicon Abundance in Photodissociation Regions

We have made one-dimensional raster-scan observations of the rho Oph and sigma Sco star-forming regions with two spectrometers (SWS and LWS) on board the ISO. In the rho Oph region, [SiII] 35um, [OI] 63um, 146um, [CII] 158um, and the H2 pure rotational transition lines S(0) to S(3) are detected, and the PDR properties are derived as the radiation field scaled by the solar neighborhood value G_0~30-500, the gas density n~250--2500 /cc, and the surface temperature T~100-400 K. The ratio of [SiII] 35um to [OI] 146um indicates that silicon of 10--20% of the solar abundance must be in the gaseous form in the photodissociation region (PDR), suggesting that efficient dust destruction is undergoing even in the PDR and that part of silicon atoms may be contained in volatile forms in dust grains. The [OI] 63um and [CII] 158um emissions are too weak relative to [OI] 146um to be accounted for by standard PDR models. We propose a simple model, in which overlapping PDR clouds along the line of sight absorb the [OI] 63um and [CII] 158um emissions, and show that the proposed model reproduces the observed line intensities fairly well. In the sigma Sco region, we have detected 3 fine-structure lines, [OI] 63um, [NII] 122um, and [CII] 158um, and derived that 30-80% of the [CII] emission comes from the ionized gas. The upper limit of the [SiII] 35um is compatible with the solar abundance relative to nitrogen and no useful constraint on the gaseous Si is obtained for the sigma Sco region.Comment: 25 pages with 7 figures, accepted in Astrophysical Journa

Responses of the soil microbial community to nitrogen fertilizer regimes and historical exposure to extreme weather events : flooding or prolonged-drought

Extreme weather events, including flooding and prolonged-drought, may establish long-lasting effects on soil biotic and abiotic properties, thus influencing ecosystem functions including primary productivity in subsequent years. Nitrogen (N) fertilizer addition often improves soil fertility, thereby potentially alleviating legacy effects on soil function and plant productivity. The soil microbial community plays a central role in mediating soil functioning; however, little is known about the legacy impacts of extreme weather events and N fertilizer addition on soil bacterial communities and the key processes involved in carbon (C) cycling. Here, the potential legacy effects of waterlogging, prolonged-drought and N fertilizer addition (0, 100, 200 and 300 kg N/ha) on soil bacteria and microbial respiration were investigated. The abundance, diversity and composition of the bacterial community, and basal and induced-respiration rates, in a farming soil system were examined, using quantitative PCR, high-throughput DNA sequencing, and MicroResp™. Soils previously exposed to short-term waterlogging events and prolonged-drought (by air-drying for 4 months) were used in our study. Prolonged drought, but not waterlogging, had a strong legacy effect on the soil bacterial community and microbial respiration. The addition of N fertilizer up to 300 kg N/ha could not fully counteract the legacy effects of prolonged-drought on soil bacteria. However, N addition did increase bacterial abundance and diversity, and inhibited soil microbial respiration. Significant correlations between microbial respiration and bacterial community structure were observed, but N addition weakened these relationships. Our results suggest that the resilience (rate of recovery) of soil bacterial communities and functions to prolonged-drought is limited in farming systems, and therefore, may take a long time to recover completely. Subsequently, this should be explicitly considered when developing adaptation strategies to alleviate the impacts of extreme weather events

Notch signaling during human T cell development

Notch signaling is critical during multiple stages of T cell development in both mouse and human. Evidence has emerged in recent years that this pathway might regulate T-lineage differentiation differently between both species. Here, we review our current understanding of how Notch signaling is activated and used during human T cell development. First, we set the stage by describing the developmental steps that make up human T cell development before describing the expression profiles of Notch receptors, ligands, and target genes during this process. To delineate stage-specific roles for Notch signaling during human T cell development, we subsequently try to interpret the functional Notch studies that have been performed in light of these expression profiles and compare this to its suggested role in the mouse

Asynchronous combinatorial action of four regulatory factors activates Bcl11b for T cell commitment

During T cell development, multipotent progenitors relinquish competence for other fates and commit to the T cell lineage by turning on Bcl11b, which encodes a transcription factor. To clarify lineage commitment mechanisms, we followed developing T cells at the single-cell level using Bcl11b knock-in fluorescent reporter mice. Notch signaling and Notch-activated transcription factors collaborate to activate Bcl11b expression irrespectively of Notch-dependent proliferation. These inputs work via three distinct, asynchronous mechanisms: an early locus 'poising' function dependent on TCF-1 and GATA-3, a stochastic-permissivity function dependent on Notch signaling, and a separate amplitude-control function dependent on Runx1, a factor already present in multipotent progenitors. Despite their necessity for Bcl11b expression, these inputs act in a stage-specific manner, providing a multitiered mechanism for developmental gene regulation