958 research outputs found
Nuclear Medium Effects in the Relativistic Treatment of Quasifree Electron Scattering
Non-relativistic reduction of the S-matrix for the quasifree electron
scattering process is studied in order to
understand the source of differences between non-relativistic and relativistic
models. We perform an effective Pauli reduction on the relativistic expression
for the S-matrix in the one-photon exchange approximation. The reduction is
applied to the nucleon current only; the electrons are treated fully
relativistically. An expansion of the amplitude results in a power series in
the nuclear potentials. The series is found to converge rapidly only if the
nuclear potentials are included in the nuclear current operator. The results
can be cast in a form which reproduces the non-relativistic amplitudes in the
limit that the potentials are removed from the nuclear current operator. Large
differences can be found between calculations which do and do not include the
nuclear potentials in the different orders of the nuclear current operator. In
the high missing momentum region we find that the non-relativistic calculations
with potentials included in the nuclear current up to second order give results
which are close to those of the fully relativistic calculation. This behavior
is an indication of the importance of the medium modifications of the nuclear
currents in this model, which are naturally built into the relativistic
treatment of the reaction.Comment: Latex, 26 pages including 5 uuencoded postscript figures. accepted
for publication in Phys. Rev. C
NEGATIVE INTERRELATIONSHIP BETWEEN NUMBER OF BERSEEM CUTS AND COTTON YIELD AS A FOLLOWING CROP
The present investigation was carried out at the Experimental Farm of the Faculty of Agriculture at Fayoum, Cario University at Dalla, Fayoum Governorate during the two seasons 2000/2001 and 2001/2002. The aim of this investigation was to study the effect of organic manure and number of berseem cuts on cotton yield and its components and fiber traits. The obtained results indicate that only plant height at harvest, number of fruiting branches / plant and the height of the 1st fruiting branch were significantly affected by organic manure (O.M.) application. On the other hand, organic manure did not affect significantly the seed cotton yield, yield components and fiber quality traits. Cotton planting dates affected significantly all studied vegetative growth, seed cotton yield, yield components and fiber quality traits. Early planting date (1st week of March) showed significant superiority over the other two planting dates (1st week of April & May) in number of fruiting branches/ plant, number of days to 1st flower appearance and 1st boll opening, number and weight of open bolls/ plant in the 1st& 2nd pickings, seed cotton yield, lint percentages and studied fiber quality traits. The decreases in the total seed cotton yield attributed to the late planting dates (1st week of April & May) amounted 26.4 and 84.8% and 30.6 and 84.1% of March planting with the treatments of 10 and 20 m3/ fad organic manure, respectively
Fatal bilateral pneumonitis after locoregional thoracic chemoradiation in a transplanted patient under immunosuppressive therapy
Background: After thoracic radiotherapy a pneumonitis may occur, mostly confined to the irradiated volume of the lung. In general, it resolves spontaneously without long-term effects. Case Report: A 68-year-old man was diagnosed with a stage IIIA adenocarcinoma of the lung and was treated with sequential chemoradiation. He had a heart and kidney transplant for which an immunosuppressant was taken. During the fourth week of radiotherapy, he developed a bilateral interstitial pneumonia. Despite antibiotics and steroids, the patient died twelve days after the onset of complaints due to respiratory failure. Autopsy showed in all pulmonary lobes extensive diffuse alveolar damage, probably leading to respiratory insufficiency and death. Literature and Conclusion: Bilateral pneumonitis after radiotherapy is thought to be an immunologically-mediated response, which usually resolves without long-term effects. Since in radiation pneumonitis an increase in T-cells is described, the suppression of these cells by an immunosuppressant might have exaggerated the pulmonary toxicity
Preliminary Investigation of the Corrosion Behavior of Proprietary Micro-alloyed Steels in Aerated and Deaerated Brine Solutions
The corrosion performance of fairly new generation of micro-alloyed steels was compared in different concentrations of aerated and deaerated brines. Electrochemical polarization, weight loss and surface analyses techniques were employed. The results showed a threshold of corrosion rate at 3.5 wt.% NaCl in both aerated and deaerated solutions. The average corrosion current density for steel B, for example, increased from 1.3 µA cm¯² in 1 wt.% NaCl to 1.5 µA cm¯² in 3.5 wt.% NaCl, but decreased to 1.4 µA cm¯² in 10 wt.% deaerated NaCl solutions. The aerated solutions exhibited an average of over 80% increase in corrosion current density in the respective concentrations when compared with the deaerated solution. These results can be attributed to the effects of dissolved oxygen (DO) which has a maximum solubility in 3.5 wt.% NaCl. DO as a depolarizer and electron acceptor in cathodic reactions accelerates anodic metal dissolution. The difference in carbon content and microstructures occasioned by thermo-mechanical treatment contributed to the witnessed variation in corrosion performance of the steels. Specifically, the results of the various corrosion techniques corroborated each other and showed that the corrosion rate of the micro-alloyed steels can be ranked as CR[Steel A] < CRₓ₆₅ < CR[Steel B] < CR[Steel C]
Relativistic versus Nonrelativistic Optical Potentials in A(e,e'p)B Reactions
We investigate the role of relativistic and nonrelativistic optical
potentials used in the analysis of () data. We find that the
relativistic calculations produce smaller () cross sections even in the
case in which both relativistic and nonrelativistic optical potentials fit
equally well the elastic proton--nucleus scattering data. Compared to the
nonrelativistic impulse approximation, this effect is due to a depletion in the
nuclear interior of the relativistic nucleon current, which should be taken
into account in the nonrelativistic treatment by a proper redefinition of the
effective current operator.Comment: Added one new figure, the formalism section has been enlarged and the
list of references updated. Added one appendix. This version will appear in
Phys. Rev. C. Revtex 3.0, 6 figures (not included). Full postscript version
of the file and figures available at
http://www.nikhefk.nikhef.nl/projects/Theory/preprints
Breakup Reactions of 11Li within a Three-Body Model
We use a three-body model to investigate breakup reactions of 11Li (n+n+9Li)
on a light target. The interaction parameters are constrained by known
properties of the two-body subsystems, the 11Li binding energy and
fragmentation data. The remaining degrees of freedom are discussed. The
projectile-target interactions are described by phenomenological optical
potentials. The model predicts dependence on beam energy and target,
differences between longitudinal and transverse momentum distributions and
provides absolute values for all computed differential cross sections. We give
an almost complete series of observables and compare with corresponding
measurements. Remarkably good agreement is obtained. The relative neutron-9Li
p-wave content is about 40%. A p-resonance, consistent with measurements at
about 0.5 MeV of width about 0.4 MeV, seems to be necessary. The widths of the
momentum distributions are insensitive to target and beam energy with a
tendency to increase towards lower energies. The transverse momentum
distributions are broader than the longitudinal due to the diffraction process.
The absolute values of the cross sections follow the neutron-target cross
sections and increase strongly for beam energies decreasing below 100 MeV/u.Comment: 19 pages, 14 figures, RevTeX, psfig.st
Molecular Screening of <i>VAX1</i> Gene Polymorphisms Uncovered the Genetic Heterogeneity of Non-Syndromic Orofacial Cleft in Saudi Arabian Patients
Objective: Nonsyndromic orofacial cleft (NSOFC) including cleft lip with or without cleft palate (CL±P) and cleft palate (CP) are multifactorial developmental disorders with both genetic and environmental etiological factors. In this study we investigated the association between CL±P and CP, and two polymorphisms previously determined using genome-wide association studies, as well as the association between consanguinity and CL±P and CP.
Methods: DNA was extracted from saliva specimens from 171 triads consisting of affected individuals and their parents, as well as 189 control triads (matched for age, gender, and location) that were recruited from 11 referral hospitals in Saudi Arabia. Two polymorphisms, rs4752028 and rs7078160, located in the VAX1 gene were genotyped using real-time polymerase chain reaction. A transmission disequilibrium test was carried out using the Family-Based Association Test and PLINK (genetic tool-set) to measure the parent-of-origin effect.
Results: Significant differences were found between affected individuals and the control group. In the case of the rs4752028 risk allele in cleft, the phenotypes were: CL±P (fathers: odds ratio [OR] 2.16 [95% CI 1.38–3.4]; mothers: OR 2.39 [95% CI 1.53–3.71]; and infants: OR 2.77 [95% CI 1.77–4.34]) and CP (fathers: OR 2.24 [95% CI 1.15–4.36] and infants: OR 2.43 [95% CI 1.25–4.7]). For CL±P and the rs7078160 risk allele, the phenotypes were: (fathers: OR 1.7 [95% CI 1.05–2.86]; mothers: OR 2.43 [95% CI 1.49–3.97]; and infants: OR 2.34 [95% CI 1.44–3.81]). In terms of consanguinity, we found significant association between consanguinity and the rs4752028 polymorphism minor allele among CL±P compared with controls (p = 0.001).
Conclusion: This is the first study to find a relationship between these two loci on 10q25 (rs4752028 and rs7078160) and NSOFC in a population with high levels of consanguinity
Opinion dynamics: models, extensions and external effects
Recently, social phenomena have received a lot of attention not only from
social scientists, but also from physicists, mathematicians and computer
scientists, in the emerging interdisciplinary field of complex system science.
Opinion dynamics is one of the processes studied, since opinions are the
drivers of human behaviour, and play a crucial role in many global challenges
that our complex world and societies are facing: global financial crises,
global pandemics, growth of cities, urbanisation and migration patterns, and
last but not least important, climate change and environmental sustainability
and protection. Opinion formation is a complex process affected by the
interplay of different elements, including the individual predisposition, the
influence of positive and negative peer interaction (social networks playing a
crucial role in this respect), the information each individual is exposed to,
and many others. Several models inspired from those in use in physics have been
developed to encompass many of these elements, and to allow for the
identification of the mechanisms involved in the opinion formation process and
the understanding of their role, with the practical aim of simulating opinion
formation and spreading under various conditions. These modelling schemes range
from binary simple models such as the voter model, to multi-dimensional
continuous approaches. Here, we provide a review of recent methods, focusing on
models employing both peer interaction and external information, and
emphasising the role that less studied mechanisms, such as disagreement, has in
driving the opinion dynamics. [...]Comment: 42 pages, 6 figure
The Hybrid SPECT/CT as an Additional Lymphatic Mapping Tool in Patients with Breast Cancer
Background Conventional lymphoscintigraphy does not always define the exact anatomic location of a sentinel node. The lymphatic drainage pattern may be unusual or may not be shown at all. The recently introduced hybrid SPECT/CT imaging could help overcome these difficulties. SPECT is a tomographic version of conventional lymphoscintigraphy and the images have better contrast and resolution. When fused with the anatomical details provided by CT into one image, a meaningful surgical ‘‘roadmap’’ can be created. So far, there is little literature on the use of hybrid SPECT/CT in lymphatic mapping in patients with breast cancer. The purpose of this review was to report on these publications, including our own experience, focusing on patient selection, SPECT/CT settings, anatomic localization, and the detection of additional sentinel nodes. Methods The majority of investigators did not formulate indications for additional SPECT/CT after conventional imaging but scanned all patients eligible for sentinel node biopsy. The SPECT/CT settings used in the studies of this review were mostly similar, but the methods used for conventional imaging were more variable. Results All studies demonstrated an improved anatomical localization by performing additional SPECT/CT; sentinel nodes outside the axilla or nodes close to the injection sit
State Norms, Religious Norms, and Claims of Plural Normativity under Democratic Constitutions
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