90 research outputs found
Highlights and Perspectives of the JLab Spin Physics Program
Nucleon spin structure has been an active and exciting subject of interest
for the last three decades. Recent precision spin-structure data from Jefferson
Lab have significantly advanced our knowledge of nucleon structure in the
valence quark (high-x) region and improved our understanding of higher-twist
effects, spin sum rules and quark-hadron duality. First, results of spin sum
rules and polarizabilities in the low to intermediate Q^2 region are presented.
Comparison with theoretical calculations are discussed. Surprising
disagreements of Chiral Perturbation Theory calculations with experimental
results on the generalized spin polarizability, \delta_{LT}, were found. Then,
precision measurements of the spin asymmetry in the high-x region are
presented. They provide crucial input for global fits to world data to extract
polarized parton distribution functions. The up and down quark spin
distributions in the nucleon were extracted. The results for \Delta d/d
disagree with the leading-order pQCD prediction assuming hadron helicity
conservation. Results of precision measurements of the g_2 structure function
to study higher-twist effects are presented. The data indicate a significant
higher-twist (twist-3 or higher) effect. The second moment of the spin
structure functions and the twist-3 matrix element d_2 results were extracted.
The high Q^2 result was compared with a Lattice QCD calculation. Results on the
resonance spin-structure functions in the intermediate Q^2 range are presented,
which, in combination with DIS data, enable a detailed study of quark-hadron
duality in spin-structure functions. Finally, an experiment to study neutron
transversity and transverse spin asymmetries is discussed. A future plan with
the 12 GeV energy upgrade at JLab is briefly outlined.Comment: 15 pages, 8 figures, to be published in Proceedings of
Prague-Spin200
Childhood obesity intervention studies: A narrative review and guide for investigators, authors, editors, reviewers, journalists, and readers to guard against exaggerated effectiveness claims
Being able to draw accurate conclusions from childhood obesity trials is important to make advances in reversing the obesity epidemic. However, obesity research sometimes is not conducted or reported to appropriate scientific standards. To constructively draw attention to this issue, we present 10 errors that are commonly committed, illustrate each error with examples from the childhood obesity literature, and follow with suggestions on how to avoid these errors. These errors are as follows: using self-reported outcomes and teaching to the test; foregoing control groups and risking regression to the mean creating differences over time; changing the goal posts; ignoring clustering in studies that randomize groups of children; following the forking paths, subsetting, p-hacking, and data dredging; basing conclusions on tests for significant differences from baseline; equating âno statistically significant differenceâ with âequally effectiveâ; ignoring intervention study results in favor of observational analyses; using one-sided testing for statistical significance; and stating that effects are clinically significant even though they are not statistically significant. We hope that compiling these errors in one article will serve as the beginning of a checklist to support fidelity in conducting, analyzing, and reporting childhood obesity research
Nutrition for the ageing brain: towards evidence for an optimal diet
As people age they become increasingly susceptible to chronic and extremely debilitating brain diseases. The precise cause of the neuronal degeneration underlying these disorders, and indeed normal brain ageing remains however elusive. Considering the limits of existing preventive methods, there is a desire to develop effective and safe strategies. Growing preclinical and clinical research in healthy individuals or at the early stage of cognitive decline has demonstrated the beneficial impact of nutrition on cognitive functions. The present review is the most recent in a series produced by the Nutrition and Mental Performance Task Force under the auspice of the International Life Sciences Institute Europe (ILSI Europe). The latest scientific advances specific to how dietary nutrients and non-nutrient may affect cognitive ageing are presented. Furthermore, several key points related to mechanisms contributing to brain ageing, pathological conditions affecting brain function, and brain biomarkers are also discussed. Overall, findings are inconsistent and fragmented and more research is warranted to determine the underlying mechanisms and to establish dose-response relationships for optimal brain maintenance in different population subgroups. Such approaches are likely to provide the necessary evidence to develop research portfolios that will inform about new dietary recommendations on how to prevent cognitive decline
Tipping the scales:Lessons from simple model systems on inositol imbalance in neurological disorders
Pelagic seabirds as biomonitors of persistent organic pollutants in the Southwestern Atlantic
Persistent Organic Pollutants (POPs) are accumulated through time and can exert different effect on ecosystems. POPs and Chlorpyrifos, a current use pesticide, were assessed in body feathers of males and females of Black-browed albatross (Thalassarche melanophris, BBA) and Cape petrels (Daption capense, CAP) during their non-breeding seasons at the Patagonian Shelf, Argentina. Chlorpyrifos showed the highest values among all pollutants in both species (49.56â84.88 ng gâ1), resulting from current agricultural practices. The pattern OCPs > PCBs > PBDEs was observed in both species, and CAP showed higher concentrations than BBA probably as a consequence of higher lipid mobilization and pollutants availability during dispersion. Non-significant differences between sexes about POPs levels were found; however a slight tendency was observed, females>males in CAP, and males>females in BBA. More attention and further studies are needed to understand seabirds' physiology and its relationship with the pollutants distribution in their tissues and considering breeding season.Fil: Quadri AdroguĂ©, Agustina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de EcotoxicologĂa; ArgentinaFil: Miglioranza, Karina Silvia Beatriz. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de EcotoxicologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Copello, SofĂa. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de BiologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Favero, Marco. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de BiologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Seco Pon, Juan Pablo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de BiologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin
Nutrition for the ageing brain: towards evidence for an optimal diet
As people age they become increasingly susceptible to chronic and extremely debilitating brain diseases. The precise cause of the neuronal degeneration underlying these disorders, and indeed normal brain ageing remains however elusive. Considering the limits of existing preventive methods, there is a desire to develop effective and safe strategies. Growing preclinical and clinical research in healthy individuals or at the early stage of cognitive decline has demonstrated the beneficial impact of nutrition on cognitive functions. The present review is the most recent in a series produced by the Nutrition and Mental Performance Task Force under the auspice of the International Life Sciences Institute Europe (ILSI Europe). The latest scientific advances specific to how dietary nutrients and non-nutrient may affect cognitive ageing are presented. Furthermore, several key points related to mechanisms contributing to brain ageing, pathological conditions affecting brain function, and brain biomarkers are also discussed. Overall, findings are inconsistent and fragmented and more research is warranted to determine the underlying mechanisms and to establish dose-response relationships for optimal brain maintenance in different population subgroups. Such approaches are likely to provide the necessary evidence to develop research portfolios that will inform about new dietary recommendations on how to prevent cognitive decline
Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run
Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society
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Index of Mining Properties in Pima County, Arizona
âIndex of Mining Properties in Pima County, Arizonaâ is the second of the planned series covering the counties of the State. The first, on Cochise County, was published in 1973 as Arizona Bureau of Mines Bulletin 187. The total mineral output from Arizona for over one hundred years has come from many mines, ranging from major operations to small mines and prospects. The record of those opera tions are scattered in numerous publications of Federal and State agencies, in articles in various technical journals, in public and private reports, and in newspaper clippings. Many such sources are not readily available to persons seeking such information. Thus these indices are designed to provide, in a concise form, as much information on min ing properties as may be found. No attempt has been made to name and describe every mining property that may have been located. The selection has been made by the compiler on the basis of production records, special geologic or mineralogic character, or importance in relation to known or possibly hidden mineral resources. The identification of areas of high probability for mineral that might become economic to mine is impor tant not only from the standpoint of a future national re source but also in planning the best use for the land involved.Published in 1974. Reprinted in 1984.This is a poor quality scan and should be replaced as time allows.Documents in the AZGS Documents Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected])
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Index of Mining Properties in Santa Cruz County, Arizona
"Index of Mining Properties in Santa Cruz County, Arizona" is the third of the series covering the counties of the State. The first two, covering Cochise and Pima Counties, were published as Arizona Bureau of Mines Bulletins 187 (1973) and 189 (1974)respectively. Arizona's important and large mineral output has come from numerous major operations and small mines or prospects for some 300 years, from the time of the early Spanish prospecting inwhat is nowSanta Cruz County. The records of the mining activities are scattered in historical documents and records, publications of individuals and Federal and State agencies, articles in technical journals, public and private reports, and newspaper clippings. Many such sources are not readily available to those seeking such information and thus these indices are designed to provide, in a concise form, a summary of information on the mining properties and the more important sources of the information. No attempt has been made to name and describe every mining property or prospect that may have been located or worked.Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected]
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