1,898 research outputs found
Fermion masses in noncommutative geometry
Get PDFRecent indications of neutrino oscillations raise the question of the
possibility of incorporating massive neutrinos in the formulation of the
Standard Model (SM) within noncommutative geometry (NCG). We find that the NCG
requirement of Poincare duality constrains the numbers of massless quarks and
neutrinos to be unequal unless new fermions are introduced. Possible scenarios
in which this constraint is satisfied are discussed.Comment: 4 pages, REVTeX; typos are corrected in (19), "Possible Solutions"
and "Conclusion" are modified; additional calculational details are included;
references are update
Molecular profiling of resident and infiltrating mononuclear phagocytes during rapid adult retinal degeneration using single-cell RNA sequencing.
Get PDFNeuroinflammation commonly accompanies neurodegeneration, but the specific roles of resident and infiltrating immune cells during degeneration remains controversial. Much of the difficulty in assessing myeloid cell-specific functions during disease progression arises from the inability to clearly distinguish between activated microglia and bone marrow-derived monocytes and macrophages in various stages of differentiation and activation within the central nervous system. Using an inducible model of photoreceptor cell death, we investigated the prevalence of infiltrating monocytes and macrophage subpopulations after the initiation of degeneration in the mouse retina. In vivo retinal imaging revealed infiltration of CCR2+ leukocytes across retinal vessels and into the parenchyma within 48 hours of photoreceptor degeneration. Immunohistochemistry and flow cytometry confirmed and characterized these leukocytes as CD11b+CD45+ cells. Single-cell mRNA sequencing of the entire CD11b+CD45+ population revealed the presence of resting microglia, activated microglia, monocytes, and macrophages as well as 12 distinct subpopulations within these four major cell classes. Our results demonstrate a previously immeasurable degree of molecular heterogeneity in the innate immune response to cell-autonomous degeneration within the central nervous system and highlight the necessity of unbiased high-throughput and high-dimensional molecular techniques like scRNAseq to understand the complex and changing landscape of immune responders during disease progression
Resolution studies of cosmic-ray tracks in a TPC with GEM readout
Full text linkA large volume TPC is a leading candidate for the central tracking detector
at a future high energy linear collider. To improve the resolution a new
readout based on micro-pattern gas detectors is being developed. Measurements
of the spatial resolution of cosmic-ray tracks in a GEM TPC are presented. We
find that the resolution suffers if the readout pads are too wide with respect
to the charge distribution at the readout plane due to insufficient charge
sharing. For narrow pads of 2 x 6 mm**2 we measure a resolution of 100
micometer at short drift distances in the absence of an axial magnetic field.
The dependence of the spatial resolution as a function of drift distance allows
the determination of the underlying electron statistics. Our results show that
the present technique uses about half the statistical power available from the
number of primary electrons. The track angle effect is observed as expected.Comment: 18 pages, 8 figures, version as published in Nucl. Inst. Met
CHARACTERIZING THE STATISTICAL DISTRIBUTION OF ORGANIC CARBON AND EXTRACTABLE PHOSPHORUS AT A REGIONAL SCALE
Get PDFGreater awareness of potential environmental problems has created the need to monitor total organic carbon (TOC) and extractable phosphorus (P) concentrations at a regional scale. The probability distribution of these soil properties can have a significant effect on the power of statistical tests and the quality of inferences applied to these properties. The objectives of this study were to: (1) evaluate the probability distribution of TOC and extractable P at the regional scale in three Major Land Resource Areas (MLRA), and (2) identify appropriate transformations that will result in a normal distribution. Both TOC and extractable P were non-normally distributed in all three MLRAs. Suggested power transformations did not result in normality, but a natural log and negative binomial transformation did produce distributions that met the assumptions of normality in most cases. Statistical analysis of TOC and extractable P data at the regional scale will need to take into account the non-normal distribution of these properties for accurate and precise estimates
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