4,296 research outputs found
DVCS with CLAS
Generalized parton distributions provide a unifying framework for the
interpretation of exclusive reactions at high . The most promising
reaction for the investigation of these distributions is the hard production of
photons using Deeply Virtual Compton Scattering (DVCS). This reaction can be
accessed experimentally by determining the production asymmetry using polarized
electrons on a proton target. Pioneering experiments with CLAS and HERMES have
produced the first measurements of this asymmetry. We will review the current
experimental program to study DVCS at Jefferson Lab. Recent high statistics
data taken with CLAS at 5.75 GeV allows us to determine this asymmetry at low
- in the valence region (=0.1-0.5) up to a of 4 GeV.Comment: 5 pages, 3 figures, Conference on the Intersections of Particle and
Nuclear Physics, New York City, May 19-24, 200
Review of Recent Jlab Results
High quality polarized electron beams at Jefferson Lab make possible
precision measurements of hadronic properties in the regime of strongly
interacting QCD. We will describe a few programs at Jefferson Lab that are
making measurements that link the basic static properties of hadrons to their
quark sub-structure. For example, parity-violating electron proton elastic
scattering probes the spatial distribution of strange quarks in the nucleon.
The nucleon-Delta transition form factors give us information about the
deformation of nucleons and Deltas. Finally, new high statistics measurements
of photons scattering off proton and deuteron targets are used to set upper
limits on the production of exotic baryons with strangeness S=+1. These
examples will be used to illustrate the capabilities and focus of the
experimental program at JLab.Comment: Contribution to XI International Conference on Hadron Spectroscopy, 4
figure
JLab: Probing Hadronic Physics with Electrons and Photons
Precision measurements of the structure of nucleons and nuclei in the regime
of strong interaction QCD are now possible with the availability of high
current polarized electron beams, polarized targets, and recoil polarimeters,
in conjunction with modern spectrometers and detector instrumentation. The
physics at JLab will be highlighted using two recent measurements of general
interest. The ratio of the proton electric to magnetic form factors indicates
the importance of the role of angular momentum in the structure of the nucleon.
The existence of 5-quark configurations in the ground state wavefunctions of
hadrons is confirmed by a narrow peak attributed to an exotic baryon with
strangeness S=+1. These and other examples will be used to illustrate the
capabilities and focus of the experimental program at JLab.Comment: V Latinamerican Symposium on Nuclear Physics, Santos, Brazil (Sept
1-5, 2003) 4 pages, 4 figure
Biomechanics in anthropology
Biomechanics is the set of tools that explain organismal movement and mechanical behavior and links the organism to the physicality of the world. As such, biomechanics can relate behaviors and culture to the physicality of the organism. Scale is critical to biomechanical analyses, as the constitutive equations that matter differ depending on the scale of the question. Within anthropology, biomechanics has had a wide range of applications, from understanding how we and other primates evolved to understanding the effects of technologies, such as the atlatl, and the relationship between identity, society, culture, and medical interventions, such as prosthetics. Like any other model, there is great utility in biomechanical models, but models should be used primarily for hypothesis testing and not data generation except in the rare case where models can be robustly validated. The application of biomechanics within anthropology has been extensive, and holds great potential for the future
HIGHAM, Nicholas ; RYAN, Martin. The Anglo-Saxon World. New Haven : Yale University Press, 2013.
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Alfred o Grande e a linhagem sagrada de Wessex : a construção de um mito de origem na Inglaterra anglo-saxônica
No final do sĂ©culo IX, as ações tomadas pelo rei Alfred, o Grande, foram decisivas para a sobrevivĂŞncia da Inglaterra anglo-saxĂ´nica contra os vikings. Seu resgate cultural iria mudar a sociedade anglo-saxĂ´nica, reforçando as defesas do reino, a polĂtica e possibilitar a unificação da Inglaterra em meados do sĂ©culo X sob o governo do rei Athelstan. Entretanto, a razĂŁo principal para este resgate nĂŁo era cultural, mas espiritual. Para esta tarefa, inspirado por obras como a Historia Ecclesiastica de Beda, um mito de origem foi forjado. Um mito que dizia que os anglo-saxões eram os herdeiros espirituais dos hebreus do Velho Testamento. E seus reis seriam descendentes de uma linhagem sagrada de um misterioso quarto filho de NoĂ©. Neste artigo iremos analisar os elementos desse mito, como se deu sua construção e sua importância para o perĂodo alfrediano.In the end of 9th century, the actions taken by King Alfred the Great were decisive for the survival of the Anglo-Saxon England against the Vikings. His cultural revival would change the Anglo-Saxon society, reinforcing the defenses of the kingdom, the politics and enable the unification of England in the mid-10th century under king Athelstan's reign. However, the main reason behind this revival was not cultural but a spiritual. For this task, inspired by the works like Bede's Historia Ecclesiastica, a myth of origins was forged. A myth that said the Anglo-Saxons were the spiritual heirs of the Hebrews of Old Testament. And their kings would be descendent of a holy lineage of a mysterious forth son of Noah. In this article we will analyze the elements of this myth, how was its construction and its importance for the Alfredian period
Experimental procedures to identify and validate specific mRNA targets of miRNAs
Functionally matured microRNAs (miRNAs) are small single-stranded non-coding RNA molecules which are emerging as important post-transcriptional regulators of gene expression and consequently are central players in many physiological and pathological processes. Since the biological roles of individual miRNAs will be dictated by the mRNAs that they regulate, the identification and validation of miRNA/mRNA target interactions is critical for our understanding of the regulatory networks governing biological processes. We promulgate the combined use of prediction algorithms, the examination of curated databases of experimentally supported miRNA/mRNA interactions, manual sequence inspection of cataloged miRNA binding sites in specific target mRNAs, and review of the published literature as a reliable practice for identifying and prioritizing biologically important miRNA/mRNA target pairs. Once a preferred miRNA/mRNA target pair has been selected, we propose that the authenticity of a functional miRNA/mRNA target pair be validated by fulfilling four well-defined experimental criteria. This review summarizes our current knowledge of miRNA biology, miRNA/mRNA target prediction algorithms, validated miRNA/mRNA target data bases, and outlines several experimental methods by which miRNA/mRNA targets can be authenticated. In addition, a case study of human endoglin is presented as an example of the utilization of these methodologies
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