390 research outputs found
Determining Dark Matter properties with a XENONnT/LZ signal and LHC-Run3 mono-jet searches
We develop a method to forecast the outcome of the LHC Run 3 based on the
hypothetical detection of signal events at XENONnT. Our
method relies on a systematic classification of renormalisable single-mediator
models for dark matter-quark interactions, and is valid for dark matter
candidates of spin less than or equal to one. Applying our method to simulated
data, we find that at the end of the LHC Run 3 only two mutually exclusive
scenarios would be compatible with the detection of signal
events at XENONnT. In a first scenario, the energy distribution of the signal
events is featureless, as for canonical spin-independent interactions. In this
case, if a mono-jet signal is detected at the LHC, dark matter must have spin
1/2 and interact with nucleons through a unique velocity-dependent operator. If
a mono-jet signal is not detected, dark matter interacts with nucleons through
canonical spin-independent interactions. In a second scenario, the spectral
distribution of the signal events exhibits a bump at non zero recoil energies.
In this second case, a mono-jet signal can be detected at the LHC Run 3, dark
matter must have spin 1/2 and interact with nucleons through a unique
momentum-dependent operator. We therefore conclude that the observation of
signal events at XENONnT combined with the detection, or the
lack of detection, of a mono-jet signal at the LHC Run 3 would significantly
narrow the range of possible dark matter-nucleon interactions. As we argued
above, it can also provide key information on the dark matter particle spin.Comment: 17 pages, 8 figures, updated operator coefficients and figures,
version accepted by PR
Wide bandgap semiconductor from a hidden 2D incommensurate graphene phase
Producing a usable semiconducting form of graphene has plagued the
development of graphene electronics for nearly two decades. Now that new
preparation methods have become available, graphene's intrinsic properties can
be measured and the search for semiconducting graphene has begun to produce
results. This is the case of the first graphene "buffer" layer grown on
SiC(0001) presented in this work. We show, contrary to assumptions of the last
forty years, that the buffer graphene layer is not commensurate with SiC. The
new modulated structure we've found resolves a long standing contradiction
where ab initio calculations expect a metallic buffer, while experimentally it
is found to be a semiconductor. Model calculations using the new incommensurate
structure show that the semiconducting -band character of the buffer comes
from partially hybridized graphene incommensurate boundaries surrounding
unperturbed graphene islands.Comment: 17 pages, 4 figures, 1 table, 47 references, supplemental material:
15 pages, 4 figure
Louisiana romp: examining the performance of traditional Cajun music within a contemporary setting
The Lost Bayou Ramblers, a young Cajun band based in South Louisiana, infuse energy and vivacity into the traditional creative expression of Cajun music, as they travel to share their sound and thus their culture with the world. I suggest that the Ramblers, in the face of globalization, are purposefully engaged in protecting and enhancing their culture by performing this roots music far and near. They offer a compelling performance and thus transport, produce, and extend their culture through music, which serves as a powerful symbol, drawing each audience into participation of it. Through a focus on the specific dynamic between culture, its music, and the performance techniques of these particular cultural practitioners, I examine how music acts as an agent of cultural understanding while simultaneously transforming the place and culture that produced it
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Lexical organization in deaf children who use British Sign Language: Evidence from a semantic fluency task
We adapted the semantic fluency task into British Sign Language (BSL). In Study 1, we present data from twenty-two deaf signers aged four to fifteen. We show that the same ‘cognitive signatures’ that characterize this task in spoken languages are also present in deaf children, for example, the semantic clustering of responses. In Study 2, we present data from thirteen deaf children with Specific Language Impairment (SLI) in BSL, in comparison to a subset of children from Study 1 matched for age and BSL exposure. The two groups' results were comparable in most respects. However, the group with SLI made occasional word-finding errors and gave fewer responses in the first 15 seconds. We conclude that deaf children with SLI do not differ from their controls in terms of the semantic organization of the BSL lexicon, but that they access signs less efficiently
Motivation for participation in adult religious education : an exploratory study
This exploratory study was conducted to gain insight into the motivations for participation in adult religious education. In-depth, informal interviews were conducted with six white, Protestant women who were active participants in the religious education programs in their congregations. One informant was selected from each decade between 20 and 70. Topics covered in the interviews were as follows: (1) Background in Participation in Religious Education; (2) Areas of Participation; (3) Reasons for Participation; (4) Relationship of Religious Education to Life; (5) Participation in Other Educational Activities
A comparison of three methods for estimating call densities of migrating bowhead whales using passive acoustic monitoring
TAM thanks partial support by Centro de Estatistica e Aplicações, Universidade de Lisboa (funded by FCT—Fundação para a Ciência e a Tecnologia, Portugal, through the project UID/MAT/00006/2013).Various methods for estimating animal density from visual data, including distance sampling (DS) and spatially explicit capture-recapture (SECR), have recently been adapted for estimating call density using passive acoustic monitoring (PAM) data, e.g., recordings of animal calls. Here we summarize three methods available for passive acoustic density estimation: plot sampling, DS, and SECR. The first two require distances from the sensors to calling animals (which are obtained by triangulating calls matched among sensors), but SECR only requires matching (not localizing) calls among sensors. We compare via simulation what biases can arise when assumptions underlying these methods are violated. We use insights gleaned from the simulation to compare the performance of the methods when applied to a case study: bowhead whale call data collected from arrays of directional acoustic sensors at five sites in the Beaufort Sea during the fall migration 2007–2014. Call detections were manually extracted from the recordings by human observers simultaneously scanning spectrograms of recordings from a given site. The large discrepancies between estimates derived using SECR and the other two methods were likely caused primarily by the manual detection procedure leading to non-independent detections among sensors, while errors in estimated distances between detected calls and sensors also contributed to the observed patterns. Our study is among the first to provide a direct comparison of the three methods applied to PAM data and highlights the importance that all assumptions of an analysis method need to be met for correct inference.Publisher PDFPeer reviewe
In Vivo Magnetic Resonance Spectroscopy of Hyperpolarized [1-
BACKGROUND: Alterations in glycolysis are central to the increasing incidence of non-alcoholic fatty liver disease (NAFLD), highlighting a need for in vivo, non-invasive technologies to understand the development of hepatic metabolic aberrations.
PURPOSE: To use hyperpolarized magnetic resonance spectroscopy (MRS) and proton density fat fraction (PDFF) magnetic resonance imaging (MRI) techniques to investigate the effects of a chronic, life-long exposure to the Western diet (WD) in an animal model resulting in NAFLD; to investigate the hypothesis that exposure to the WD will result in NAFLD in association with altered pyruvate metabolism.
STUDY TYPE: Prospective.
ANIMAL MODEL: Twenty-eight male guinea pigs weaned onto a control diet (N = 14) or WD (N = 14).
FIELD STRENGTH/SEQUENCE: 3 T; T1-weighted gradient echo, T2-weighted spin-echo, three-dimensional gradient multi-echo fat-water separation (IDEAL-IQ), and broadband point-resolved spectroscopy (PRESS) chemical-shift sequences.
ASSESSMENT: Median PDFF was calculated in the liver and hind limbs. [1-
STATISTICAL TESTS: Unpaired Student\u27s t-tests were used to determine differences in measurements between the two diet groups. The Pearson correlation coefficient was calculated to determine correlations between measurements.
RESULTS: Life-long WD consumption resulted in significantly higher liver PDFF and elevated triglyceride content in the liver. The WD group exhibited a decreased TTP for lactate production, and ex vivo analysis highlighted increased liver lactate dehydrogenase (LDH) activity.
DATA CONCLUSION: PDFF MRI results suggest differential fat deposition patterns occurring in animals fed a life-long WD characteristic of lean, or lacking excessive subcutaneous fat, NAFLD. The decreased liver lactate TTP and increased ex vivo LDH activity suggest lipid accumulation occurs in association with a shift from oxidative metabolism to anaerobic glycolytic metabolism in WD-exposed livers.
LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 1
In Vivo Magnetic Resonance Spectroscopy of Hyperpolarized [1-\u3csup\u3e13\u3c/sup\u3eC]Pyruvate and Proton Density Fat Fraction in a Guinea Pig Model of Non-Alcoholic Fatty Liver Disease Development After Life-Long Western Diet Consumption
Background: Alterations in glycolysis are central to the increasing incidence of non-alcoholic fatty liver disease (NAFLD), highlighting a need for in vivo, non-invasive technologies to understand the development of hepatic metabolic aberrations. Purpose: To use hyperpolarized magnetic resonance spectroscopy (MRS) and proton density fat fraction (PDFF) magnetic resonance imaging (MRI) techniques to investigate the effects of a chronic, life-long exposure to the Western diet (WD) in an animal model resulting in NAFLD; to investigate the hypothesis that exposure to the WD will result in NAFLD in association with altered pyruvate metabolism. Study Type: Prospective. Animal Model: Twenty-eight male guinea pigs weaned onto a control diet (N = 14) or WD (N = 14). Field Strength/Sequence: 3 T; T1-weighted gradient echo, T2-weighted spin-echo, three-dimensional gradient multi-echo fat-water separation (IDEAL-IQ), and broadband point-resolved spectroscopy (PRESS) chemical-shift sequences. Assessment: Median PDFF was calculated in the liver and hind limbs. [1-13C]pyruvate dynamic MRS in the liver was quantified by the time-to-peak (TTP) for each metabolite. Animals were euthanized and tissue was analyzed for lipid and cholesterol concentration and enzyme level and activity. Statistical Tests: Unpaired Student\u27s t-tests were used to determine differences in measurements between the two diet groups. The Pearson correlation coefficient was calculated to determine correlations between measurements. Results: Life-long WD consumption resulted in significantly higher liver PDFF and elevated triglyceride content in the liver. The WD group exhibited a decreased TTP for lactate production, and ex vivo analysis highlighted increased liver lactate dehydrogenase (LDH) activity. Data Conclusion: PDFF MRI results suggest differential fat deposition patterns occurring in animals fed a life-long WD characteristic of lean, or lacking excessive subcutaneous fat, NAFLD. The decreased liver lactate TTP and increased ex vivo LDH activity suggest lipid accumulation occurs in association with a shift from oxidative metabolism to anaerobic glycolytic metabolism in WD-exposed livers. Level of Evidence: 2. Technical Efficacy Stage: 1
Thrombopoietin Receptor Levels in Tumor Cell Lines and Primary Tumors
Thrombopoietin (TPO) receptor agonists represent a new approach for the treatment of thrombocytopenia, which may develop as a consequence of immune thrombocytopenia, chemotherapy treatment, chronic hepatitis C infection, or myelodysplastic syndromes. There are concerns that use of certain growth factors can hasten disease progression in some types of hematologic malignancies and solid tumors. In this study, expression of MPL (TPO-R) mRNA was examined in tumor cell lines, patient tumor samples (renal cell carcinoma, prostatic carcinoma, soft tissue and bony/cartilage sarcoma, colon cancer, and lymphoma), and normal tissues using microarray analysis and qRT-PCR. MPL mRNA is expressed at very low or undetectable levels compared with erythropoietin receptor (EPOR), human epidermal growth factor (ERBB2; HER2), and insulin-like growth factor-1 receptor (IGF1R) in these patient samples. These data suggest TPO-R agonists will likely preferentially stimulate proliferation and differentiation of cells of megakaryocytic lineage, potentially demonstrating their utility for correcting thrombocytopenia in clinical settings
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