2,643 research outputs found
Learning Through Crisis and Paradox in Justice-Oriented Teacher Education
In this article we explore some of the challenges, constraints, and what we refer to as glimmers of revelation that occurred during an experiential, community-based teacher education course that we designed and co-taught in spring 2015. Trying to take seriously Kumashiroâs (2009) notions that justice oriented teacher education happens âonly when we ourselves are still struggling with questions about the âwhat else,â âhow else,â and âwhere elseâ that are involvedâ in this kind of teaching [emphasis added] (p. xxv), we explore moments where we grappled with the paradox, partiality, uncertainty, and discomfort (Kumashiro, 2009) that often accompany our commitments as middle grades teacher educators attempting to enact anti-oppressive teaching practices
The twisted fourth moment of the Riemann zeta function
We compute the asymptotics of the fourth moment of the Riemann zeta function
times an arbitrary Dirichlet polynomial of length Comment: 28 pages. v2: added reference
Transcriptional profiling reveals extraordinary diversity among skeletal muscle tissues
Skeletal muscle comprises a family of diverse tissues with highly specialized functions. Many acquired diseases, including HIV and COPD, affect specific muscles while sparing others. Even monogenic muscular dystrophies selectively affect certain muscle groups. These observations suggest that factors intrinsic to muscle tissues influence their resistance to disease. Nevertheless, most studies have not addressed transcriptional diversity among skeletal muscles. Here we use RNAseq to profile mRNA expression in skeletal, smooth, and cardiac muscle tissues from mice and rats. Our data set, MuscleDB, reveals extensive transcriptional diversity, with greater than 50% of transcripts differentially expressed among skeletal muscle tissues. We detect mRNA expression of hundreds of putative myokines that may underlie the endocrine functions of skeletal muscle. We identify candidate genes that may drive tissue specialization, including Smarca4, Vegfa, and Myostatin. By demonstrating the intrinsic diversity of skeletal muscles, these data provide a resource for studying the mechanisms of tissue specialization
Double-impulse magnetic focusing of launched cold atoms.
We have theoretically investigated three-dimensional focusing of a launched cloud of cold atoms using a pair of magnetic lens pulses (the alternate-gradient method). Individual lenses focus radially and defocus axially or vice versa. The performance of the two possible pulse sequences are compared and found to be ideal for loading both 'pancake' and 'sausage' shaped magnetic/optical microtraps. It is shown that focusing aberrations are considerably smaller for double-impulse magnetic lenses compared to single-impulse magnetic lenses. An analysis of clouds focused by the double-impulse technique is presented
An Admixture Approach to Trihybrid Ancestry Variation in the Philippines with Implications for Forensic Anthropology
In this study, we investigate, for the first time from a forensic anthropological perspective, the question of mixed ancestry estimation for modern Filipinos with geographic origins in the Philippines. We derive estimates of continental ancestry using craniometrics from four sources: a new documented collection of current forensic significance from the Manila North Cemetery; the Howells cranial series representing a sample of unclaimed individuals from Manila but said largely to originate from more remote areas, with dates of death before 1940; the Hanihara sample aggregated from various locations and time periods across the Philippines; and the Hanihara series capturing various local indigenous, ethnic groups that are together identified as Philippine Negrito. Parental craniometrics are selected from the Howells dataset and more recently collected samples from Europe and Asia. Using unsupervised clustering, we investigate the algorithmically defined three-cluster, or trihybrid admixture, model to infer continental ancestry for each individual, reporting their relative proportions of Asian, European, and African admixture. We employ similar clustering procedures to identify more complex models, with a larger number of clusters, to explore patterns of affinity between our four Philippine samples and the recently acquired samples from Vietnam, Thailand, China (Hong Kong), Japan, and Korea. These analyses give insight into the relationships between both macro and micro geographic regions, such that, at the country level, we reveal how different population dynamics â whether geo-political, -economic, -historical and/or -social â structure the ancestral makeup of Asian peoples, especially in the degree of European and African admixture. From these ancestry estimates, we find that population of origin explains 38-51% of the variation in each ancestry component and we detect significant differences among the Asian samples in their quantities of ancestry. Filipinos appear considerably admixed, as they appear to carry almost 20% less Asian ancestry than the average quantity (90%) estimated for the other Asian groups. We also reveal substructure within our representation of modern Filipinos, such that differences in the patterns of three-way admixture exist between each of the four Philippine samples, finding that the Manila cemetery sample has the highest level of Asian ancestry and, as we might expect, that the Negrito sample has the greatest quantity of African ancestry. We perform additional analyses that introduce craniometrics from the Howells Australo-Melanesian series in order to more fully investigate their relationship to the Asian samples and to better understand the African contributions common to the Philippine Negritos especially, as well as the other Southeast Asians and the Spanish and Portuguese groups. By mapping the cluster patterns on a global scale, these analyses reveal, with craniometrics just as with genetic loci, patterns of affinity that are informative of the complex history of Southeast Asia, as they are suggestive of the vestiges of migration, trade, and colonialism, as well as more recent periods of isolation, marginalization, and occupation
py4DSTEM: a software package for multimodal analysis of four-dimensional scanning transmission electron microscopy datasets
Scanning transmission electron microscopy (STEM) allows for imaging,
diffraction, and spectroscopy of materials on length scales ranging from
microns to atoms. By using a high-speed, direct electron detector, it is now
possible to record a full 2D image of the diffracted electron beam at each
probe position, typically a 2D grid of probe positions. These 4D-STEM datasets
are rich in information, including signatures of the local structure,
orientation, deformation, electromagnetic fields and other sample-dependent
properties. However, extracting this information requires complex analysis
pipelines, from data wrangling to calibration to analysis to visualization, all
while maintaining robustness against imaging distortions and artifacts. In this
paper, we present py4DSTEM, an analysis toolkit for measuring material
properties from 4D-STEM datasets, written in the Python language and released
with an open source license. We describe the algorithmic steps for dataset
calibration and various 4D-STEM property measurements in detail, and present
results from several experimental datasets. We have also implemented a simple
and universal file format appropriate for electron microscopy data in py4DSTEM,
which uses the open source HDF5 standard. We hope this tool will benefit the
research community, helps to move the developing standards for data and
computational methods in electron microscopy, and invite the community to
contribute to this ongoing, fully open-source project
The early life microbiota protects neonatal mice from pathological small intestinal epithelial cell shedding
The early life gut microbiota plays a crucial role in regulating and maintaining the intestinal barrier, with disturbances in these communities linked to dysregulated renewal and replenishment of intestinal epithelial cells. Here we sought to determine pathological cell shedding outcomes throughout the postnatal developmental period, and which host and microbial factors mediate these responses. Surprisingly, neonatal mice (Day 14 and 21) were highly refractory to induction of cell shedding after intraperitoneal administration of liposaccharide (LPS), with Day 29 mice showing strong pathological responses, more similar to those observed in adult mice. These differential responses were not linked to defects in the cellular mechanisms and pathways known to regulate cell shedding responses. When we profiled microbiota and metabolites, we observed significant alterations. Neonatal mice had high relative abundances of Streptococcus, Escherichia, and Enterococcus and increased primary bile acids. In contrast, older mice were dominated by Candidatus Arthromitus, Alistipes, and Lachnoclostridium, and had increased concentrations of SCFAs and methyamines. Antibiotic treatment of neonates restored LPS-induced small intestinal cell shedding, whereas adult fecal microbiota transplant alone had no effect. Our findings further support the importance of the early life window for microbiota-epithelial interactions in the presence of inflammatory stimuli and highlights areas for further investigation
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