We report on several features in the energy spectrum from an ultralow-noise germanium detector operated deep underground. By implementing a new technique able to reject surface events, a number of ...cosmogenic peaks can be observed for the first time. We discuss an irreducible excess of bulklike events below 3 keV in ionization energy. These could be caused by unknown backgrounds, but also dark matter interactions consistent with DAMA/LIBRA. It is not yet possible to determine their origin. Improved constraints are placed on a cosmological origin for the DAMA/LIBRA effect.
Fifteen months of cumulative CoGeNT data are examined for indications of an annual modulation, a predicted signature of weakly interacting massive particle (WIMP) interactions. Presently available ...data support the presence of a modulated component of unknown origin, with parameters prima facie compatible with a galactic halo composed of light-mass WIMPs. Unoptimized estimators yield a statistical significance for a modulation of ∼2.8σ, limited by the short exposure.
A claim for evidence of dark matter interactions in the DAMA experiment has been recently reinforced. We employ a new type of germanium detector to conclusively rule out a standard isothermal ...galactic halo of weakly interacting massive particles as the explanation for the annual modulation effect leading to the claim. Bounds are similarly imposed on a suggestion that dark pseudoscalars might lead to the effect. We describe the sensitivity to light dark matter particles achievable with our device, in particular, to next-to-minimal supersymmetric model candidates.
Background In mice, group 2 innate lymphoid cells (ILC2s) likely mediate helminth immunity, inflammation, and tissue repair and remodeling. However, the involvement of ILC2s in human diseases, such ...as asthma, is not well understood. Objectives The goals of this study were to investigate whether peripheral blood specimens can be used to monitor innate type 2 immunity in human subjects and to examine whether ILC2s are involved in human asthma. Methods PBMCs from subjects with allergic asthma (AA), subjects with allergic rhinitis (AR), or healthy control (HC) subjects were cultured in vitro with IL-25 or IL-33. Flow cytometry and cell sorting were used to identify, isolate, and quantitate ILC2s in PBMCs. Results Human PBMCs produced IL-5 and IL-13 when stimulated with IL-33 or IL-25 in the presence of IL-2 without antigens. In addition, IL-7 or thymic stromal lymphopoietin were able to replace IL-2. The cell population with phenotypic ILC2 characteristics, lineage− CD127+ CRTH2+ cells, responded to IL-33 and produced large quantities of IL-5 and IL-13 but undetectable levels of IL-4. PBMCs from subjects with AA produced significantly larger amounts of IL-5 and IL-13 in response to IL-25 or IL-33 than from subjects with AR or HC. The prevalence of ILC2s in blood was greater in the AA group than in the AR group or the HC group. Conclusions Innate type 2 immune responses are increased in asthma but not in AR, suggesting potential differences in the immunopathogenesis of these diseases. Peripheral blood is useful for evaluating innate type 2 immunity in humans.
The mechanisms by which eosinophilic inflammation damages the epithelium and contributes to recurrent acute exacerbations in chronic rhinosinusitis (CRS) have not been fully elucidated.
We tested the ...hypotheses that eosinophils deposit toxic major basic protein (MBP) in the mucus and that MBP reaches concentrations able to damage the sinonasal epithelium.
Tissue specimens with mucus attached to the tissue were carefully collected from 22 patients with CRS and examined by using immunofluorescence staining for MBP. This immunofluorescence was digitally analyzed to determine the area covered by MBP and the intensity of the staining (estimating MBP concentration). Levels of MBP in extracts from nasal mucus were quantitated by means of RIA.
Heterogeneous eosinophilia was evident within tissue and mucus specimens. All tissue specimens showed intact eosinophils, but diffuse extracellular MBP deposition, as a marker of eosinophil degranulation, was rare. In contrast, all mucus specimens showed diffuse MBP throughout and abundant diffuse extracellular MBP deposition within clusters of eosinophils. Digitized analyses of MBP immunofluorescence revealed increased area coverage (
P < .0001) in mucus compared with that seen in tissue. Estimated concentrations of MBP within the clusters suggested toxic levels. MBP concentrations in mucus extract reached 11.7 μg/mL; MBP was not detectable in healthy control subjects.
In patients with CRS, eosinophils form clusters in the mucus where they release MBP, which is diffusely deposited on the epithelium, a process not observed in the tissue. Estimated MBP levels far exceed those needed to damage epithelium from the luminal side and could predispose patients with CRS to secondary bacterial infections.
Due to the emerging potential for trafficking of special nuclear material, research programs are investigating current capabilities of commercially available portable gamma ray detection systems. ...Presented in this paper are the results of three different portable high-purity germanium (HPGe) detectors used to identify short-lived fission products generated from thermal neutron interrogation of small samples of highly enriched uranium. Samples were irradiated at the Washington State University Nuclear Radiation Center’s 1 MW TRIGA reactor. The three portable, HPGe detectors used were the ORTEC MicroDetective
1
, the ORTEC Detective
2
, and the Canberra Falcon
3
. Canberra’s GENIE-2000 software was used to analyze the spectral data collected from each detector. Ultimately, these three portable detectors were able to identify a large range of fission products showing potential for material discrimination.
The most common genes for semidwarf habit in modern wheat (Triticum aestivum L.) cultivars are found at the Rht-B1 and Rht-D1 loci on chromosomes 4B and 4D, respectively. An alternative gene for ...semidwarf habit, Rht8, has shown potential as a replacement for Rht-B1b and Rht-D1b in some environments. The objective of the present study was to assess the impact of the height-reducing gene Rht8 relative to Rht-B1b and Rht-D1b on performance of spring wheat in Montana and Washington environments characterized by terminal drought stress. Evaluation of near-isogenic lines developed in four genetic backgrounds showed that Rht-B1b, Rht-D1b, and Rht8 caused height reduction of 19, 20, and 6.5%, respectively, relative to wild-type near-isogenic lines over 12 environments. An increase in grain yield was associated with reduced height for lines containing Rht-B1b and Rht-D1b based on means over the four genetic backgrounds and 10 environments. Height reduction and yield increase associated with Rht-B1b and Rht-D1b were significant in most environments. Lines with Rht8 yielded less than wild-type based on means over environments and in 3 of 10 individual environments. Reduced height lines with Rht-B1b and Rht-D1b tended to have a higher harvest index and more seed per spike than wild-type lines and reduced height lines with Rht8. In sum, our results suggest that Rht-B1b and Rht-D1b are superior to Rht8 as a source for height reduction for spring wheat in the tested environments.
We present data characterizing the performance of the first segmented, N-type Ge detector, isotopically enriched to 85% 76Ge. This detector, based on the Ortec PT62 design and referred to as SEGA ...(Segmented, Enriched Germanium Assembly), was developed as a possible prototype for neutrinoless double beta-decay measurements by the Majorana collaboration. We present some of the general characteristics (including bias potential, efficiency, leakage current, and integral cross-talk) for this detector in its temporary cryostat. We also present an analysis of the resolution of the detector, and demonstrate that for all but two segments there is at least one channel that reaches the Majorana resolution goal below 4 keV FWHM at 2039 keV, and all channels are below 4.5 keV FWHM.
Hard red spring wheat (Triticum aestivum L.) grown in rainfed environments in the northern Great Plains of North America frequently encounter drought and heat stress during grain‐fill, thus reducing ...yield. Delayed leaf senescence after heading, known as the stay‐green trait, has been found to help spring wheat tolerate drought and heat stress during grain‐fill. To better understand how the stay‐green trait relates to expression of other agronomic traits, data was analyzed from a recombinant inbred line (RIL) population derived from a ‘Vida’/MTHW0202 cross grown in rainfed and irrigated environments. The genetic architecture controlling traits measured in this study were also examined. Results found the stay‐green trait was significantly correlated to overall yield (P < .001, r = .37) in rain‐fed environments, but was not significantly correlated to yield (P = .26, r = .09) in irrigated environments. Three quantitative trait loci (QTL) located on chromosomes 2D, 4A, and 4D were associated with the stay‐green trait. The 4A stay‐green QTL, previously designated QGfd.mst‐4A, was collocated with QTL for seed number per head, thousand kernel weight, and heading date. The 4D stay‐green QTL overlaps the Rht‐D1 plant height gene, and the allele prolonging the stay‐green period co‐segregates with the wild‐type (tall) Rht‐D1a allele. Results from this study provide a better understanding of the relationship between stay‐green and agronomic traits in rainfed vs. irrigated environments. Additionally, understanding the genetic architecture controlling stay‐green and agronomic traits will aid in selecting future drought‐tolerant spring wheat varieties.
The
Majorana Collaboration is building the
Majorana Demonstrator, a 60
kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in ...Lead, SD. The
Majorana Demonstrator will search for neutrinoless double-beta decay of
76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1–10
GeV/
c
2 mass range. We have found that customized Broad Energy Germanium (BEGe) detectors produced by Canberra have several desirable features for a neutrinoless double-beta decay experiment, including low electronic noise, excellent pulse shape analysis capabilities, and simple fabrication. We have deployed a customized BEGe, the
Majorana Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and shield at the Kimballton Underground Research Facility in Virginia. This paper will focus on the detector characteristics and measurements that can be performed with such a radiation detector in a low-background environment.
PDF
