141 research outputs found
Nuclear aspects of neutral current non-standard -nucleus reactions and the role of the exotic transitions experimental limits
The nuclear aspects of flavour changing neutral current (FCNC) processes,
predicted by various new-physics models to occur in the presence of nuclei, are
examined by computing the relevant nuclear matrix elements within the context
of the quasi-particle RPA using realistic strong two-body forces. One of our
aims is to explore the role of the non-standard interactions (NSI) in the
leptonic sector and specifically: (i) in lepton flavour violating (LFV)
processes involving the neutral particles and ,
and (ii) in charged lepton flavour violating (cLFV)
processes involving the charged leptons or . As concrete
nuclear systems we have chosen the stopping targets of
conversion experiments, i.e. the nucleus of the PRIME/PRISM
experiment at J-PARC and the of the COMET at J-PARC as well
as of the Mu2e at Fermilab. These experiments have been designed to reduce the
single event sensitivity down to -- in searching for
charged lepton mixing events. Our goal is, by taking advantage of our detailed
nuclear structure calculations and using the present limits or the sensitivity
of the aforementioned exotic experiments, to put
stringent constraints on the parameters of NSI Lagrangians.Comment: 8 pages, 4 figures, 3 Tables, Physics Letters B accepte
Neutrino transition magnetic moments within the non-standard neutrino-nucleus interactions
Tensorial non-standard neutrino interactions are studied through a combined
analysis of nuclear structure calculations and a sensitivity -type of
neutrino events expected to be measured at the COHERENT experiment, recently
planned to operate at the Spallation Neutron Source (Oak Ridge). Potential
sizeable predictions on transition neutrino magnetic moments and other
electromagnetic parameters, such as neutrino milli-charges, are also addressed.
The non-standard neutrino-nucleus processes, explored from nuclear physics
perspectives within the context of quasi-particle random phase approximation,
are exploited in order to estimate the expected number of events originating
from vector and tensor exotic interactions for the case of reactor neutrinos,
studied with TEXONO and GEMMA neutrino detectors.Comment: 7 pages, 6 Figures, 2 Tables, Accepted for publication to Physics
Letters
Constraining nuclear physics parameters with current and future COHERENT data
Motivated by the recent observation of coherent elastic neutrino-nucleus
scattering (CENS) at the COHERENT experiment, our goal is to explore its
potential in probing important nuclear structure parameters. We show that the
recent COHERENT data offers unique opportunities to investigate the neutron
nuclear form factor. Our present calculations are based on the deformed Shell
Model (DSM) method which leads to a better fit of the recent CENS data,
as compared to known phenomenological form factors such as the Helm-type,
symmetrized Fermi and Klein-Nystrand. The attainable sensitivities and the
prospects of improvement during the next phase of the COHERENT experiment are
also considered and analyzed in the framework of two upgrade scenarios.Comment: 13 pages, 5 figures, 2 tables; v2: minor corrections, version to
appear in PL
Substituent effects on the gas‐phase fragmentation reactions of protonated peptides containing benzylamine‐derivatized lysyl residues
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90273/1/rcm6141.pd
Gonadal abnormalities in frogs (\u3ci\u3eLithobates\u3c/i\u3e spp.) collected from managed wetlands in an agricultural region of Nebraska, USA
Nebraska’s Rainwater Basin (RWB) provides important wetland habitat for North American migratory birds. Concern exists that pesticide and nutrient runoff from surrounding row-crops enters wetlands degrading water quality and adversely affecting birds and wildlife. Frogs may be especially vulnerable. Plains leopard (Lithobates blairi) metamorphs from RWB wetlands with varying concentrations of pesticides were evaluated for a suite of biomarkers of exposure to endocrine active chemicals. Froglets had ovarian dysgenesis, high rates of testicular oocytes, and female-biased sex ratios however, there was no clear statistical association between pesticide concentrations and biomarkers. Data interpretation was hindered because timing and duration of exposures were unknown and due to an incomplete understanding of L. blairi sexual development. Emphasis is on describing the complex developmental biology of closely-related leopard frogs, how this understanding can explain RWB L. blairi anomalies, and the need for sampling at the appropriate life stage
Facilitating mental health research for patients, clinicians and researchers: a mixed-method study
OBJECTIVES: Research registers using Consent for Contact (C4C) can facilitate recruitment into mental health research studies, allowing investigators to contact patients based on clinical records information. We investigated whether such a register was useful for mental health research, seeking the perspectives of patients and research investigators. SETTING AND DESIGN: In 2012, a C4C register was developed in a large secondary mental health provider within the UK; almost 9000 patients have joined. This mixed-method study audited the effectiveness of the register. PARTICIPANTS: A 'mystery shopper' exercise was conducted, and patients (n=21) were recruited to ask clinicians about the availability of research opportunities. Structured interviews were conducted with patients (n=52) about their experiences of being on the register. Similar interviews were conducted with 18 investigators from 19 studies, who had attempted to use the register to recruit participants. OUTCOME MEASURES: The impact of C4C on study recruitment, and whether it helped patients learn about research. RESULTS: So far, the register has provided 928 individuals with 1085 research opportunities (in 60% of cases, the individual agreed to participate in the study). Clinicians were willing to link patients to research opportunities, but often lacked information about studies. For patients, the register provided opportunities which they may not otherwise have; 27 of 52 had participated in studies since joining the register (18 participating for the first time). Most investigators used the register to supplement recruitment to their studies, but described problems in prescreening potential participants from a clinical record for complex studies. CONCLUSIONS: Although the register helped investigators recruit for studies, and provided patients with research opportunities, clinicians' input is still useful for identifying suitable participants. C4C registers should be adapted to provide clinicians with automatically updated information on local studies allowing them to match patients on their caseload with active studies
Novel neutrino-floor and dark matter searches with deformed shell model calculations
Event detection rates for WIMP-nucleus interactions are calculated for
Ga, Ge, As and I (direct dark matter detectors).
The nuclear structure form factors, that are rather independent of the
underlying beyond the Standard Model particle physics scenario assumed, are
evaluated within the context of the deformed nuclear shell model (DSM) based on
Hartree-Fock nuclear states. Along with the previously published DSM results
for Ge, the neutrino-floor due to coherent elastic neutrino-nucleus
scattering (CENS), an important source of background to dark matter
searches, is extensively calculated. The impact of new contributions to
CENS due to neutrino magnetic moments and mediators at direct
dark matter detection experiments is also examined and discussed. The results
show that the neutrino-floor constitutes a crucial source of background events
for multi-ton scale detectors with sub-keV capabilities.Comment: 16 pages, 12 figures, 3 Tables; 1 figure and 1 table added;
references added; matches published versio
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Modelling of single bubble-dynamics and thermal effects
This paper evaluates the solution effects of different Rayleigh-Plesset models (R-P) for simulating the growth/collapse dynamics and thermal behaviour of homogeneous gas bubbles. The flow inputs used for the discrete cavitation bubble calculations are obtained from Reynolds-averaged Navier-Stokes simulations (RANS), performed in high-pressure nozzle holes. Parametric 1-D results are presented for the classical thermal R-P equation [1] as well as for refined models which incorporated compressibility corrections and thermal effects [2, 3]. The thermal bubble model is coupled with the energy equation, which provides the temperature of the bubble as a function of conduction/convection and radiation heat-transfer mechanisms. For approximating gas pressure variations a high-order virial equation of state (EOS) was used, based on Helmholtz free energy principle [4]. The coded thermal R-P model was validated against experimental measurements [5] and model predictions [6] reported in single-bubble sonoluminescence (SBSL)
Widespread occurrence of intersex in black basses (\u3ci\u3eMicropterus\u3c/i\u3e spp.) from U.S. rivers, 1995–2004
Intersex occurrence in freshwater fishes was evaluated for nine river basins in the United States. Testicular oocytes (predominantly male testes containing female germ cells) were the most pervasive form of intersex observed, even though similar numbers of male (n = 1477) and female (n = 1633) fish were examined. Intersex was found in 3% of the fish collected. The intersex condition was observed in four of the 16 species examined (25%) and in fish from 34 of 111 sites (31%). Intersex was not found in multiple species from the same site but was most prevalent in largemouth bass (Micropterus salmoides; 18% of males) and smallmouth bass (M. dolomieu; 33% of males). The percentage of intersex fish per site was 8–91% for largemouth bass and 14–73% for smallmouth bass. The incidence of intersex was greatest in the southeastern United States, with intersex largemouth bass present at all sites in the Apalachicola, Savannah, and Pee Dee River Basins. Total mercury, trans-nonachlor, p,p\u27-DDE, p,p\u27-DDD, and total PCBs were the most commonly detected chemical contaminants at all sites, regardless of whether intersex was observed. Although the genotype of the intersex fish was not determined, the microscopic appearance of the gonads, the presence of mature sperm, and the concentrations of sex steroid hormones and vitellogenin indicate the intersex bass were males. Fewre productive endpoints differed significantly among male and intersex bass; plasma vitellogenin concentration in males was not a good indicator of intersex presence. Hierarchical linkages of the intersex condition to reproductive function will require a more quantitative measure of intersex (e.g. severity index) rather than presence or absence of the condition. The baseline incidence of intersex gonadal tissue in black basses and other freshwater fishes is unknown, but intersex prevalence may be related to collection season, age, and endocrine active compounds in the environment. Intersex was not found in largemouth bass older than five years and was most common in 1–3-year-old male largemouth bass. The cause(s) of intersex in these species is also unknown, and it remains to be determined whether the intersex we observed in largemouth and smallmouth bass developed during sex differentiation in early life stages, during exposure to environmental factors during adult life stages, or both
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