Lepton Scattering off Few-Nucleon Systems at Medium and High Energies

The interpretation of recent Jlab experimental data on the exclusive process A(e,e'p)B off few-nucleon systems are analyzed in terms of realistic nuclear wave functions and Glauber multiple scattering theory, both in its original form and within a generalized eikonal approximation. The relevance of the exclusive process 4He(e,e'p)^3H for possible investigations of QCD effects is illustrated.Comment: 6 pages, 3 figures. Plenary talk given by C. Ciofi degli Atti at the XX European Conference "Few Body Problems in Physics", Pisa, Italy, September 2007. To appear in Few-Body System

On the effects of the final state interaction in the electro-disintegration of the deuteron at intermediate and high energies

The role of the final state interactions (FSI) in the inclusive quasi-elastic disintegration of the deuteron is investigated treating the two-nucleon final state within the exact continuum solutions of the non-relativistic Schroedinger equation, as well as within the Glauber multiple scattering approach. It is shown that for values of the Bjorken scaling variable $x_{Bj}\simeq 1$ both approaches provide similar results, unless the case $x_{Bj}\gtrsim 1$, where they appreciably disagree. It is demonstrated that present experimental data, which are mostly limited to a region of four-momentum transfer ($Q^2 \lesssim 4 (GeV/c)^2$) where the Center-of-Mass energy of the final state is below the pion threshold production, can be satisfactorily reproduced by the approach based on the exact solution of the Schroedinger equation and not by the Glauber approach. It is also pointed out that the latter, unlike the former, does not satisfy the inelastic Coulomb sum rule, the violation being of the order of about 20%.Comment: 16 LaTeX pages, 10 eps-figures, 1 tabl

Ground-state correlations and final state interactions in the process 3He(e,e'pp)n

The two-proton emission process $^3He(e,e'pp)n$ is theoretically investigated using realistic three-nucleon wave functions and taking the final state interaction into account by an approach which can be used when the value of the three-nucleon invariant mass is either below or above the pion emission threshold. Various kinematical conditions which enhance or minimize the effects of the final state interaction are thoroughly analyzed.Comment: 26 pages, 12 eps-figures. Introduction and abstract updated, few references added and Apendix A remove

Nuclear effects in Deep Inelastic Scattering of polarized electrons off polarized 3He and the neutron spin structure functions

It is shown that the nuclear effects playing a relevant role in Deep Inelastic Scattering of polarized electrons by polarized $^3$He are mainly those arising from the effective proton and neutron polarizations generated by the $S'$ and $D$ waves in $^3$He. A simple and reliable equation relating the neutron, $g_1^n$, and $^3$He, $g_1^3$, spin structure functions is proposed. It is shown that the measurement of the first moment of the $^3$He structure function can provide a significant check of the Bjorken Sum Rule.Comment: 11 pages (revTeX), DFUPG 75/93; 5 (postscript) figures available upon request from the author

Analisis Peranan Algoritma Angka dan Kata dalam Peningkatan Kemampuan Problem-solving Matematika pada Siswa Satap SMPN 6 Kupang Tengah

Pembelajaran matematika pada umumnya tidak terlepas dari perhitungan, penyusunan pola/bentuk dan pemikiran logik matematik. Oleh sebab itu, metode pembelajarannya haruslah asyik dan menyenangkan. Hal ini merupakan tantangan bagi para pendidik pada umumnya dan guru sekolah menengah pertama khususnya agar memotivasi anak didik/siswa-siswinya  untuk memiliki beberapa keahlian matematika. Keahlian matematika berupa aritmatika, algoritma angka maupun algoritma kata kata sangat penting saat menyelesaikan soal-soal matematika terlebih soal cerita atau soal yang membutuhkan daya nalar (logika) yang benar. Tujuan dari penelitian ini adalah untuk menyelidiki kesulitan siswa dalam kemampuan aritmatika, algoritma angka dan algoritma kata-kata saat menyelesaikan permasalahan (problem-solving) matematika dan menemukan metode pembelajaran matematika yang dapat membantu siswa SATAP SMPN 6 Kupang Tengah dalam menyelesaikan persoalan matematika berdasarkan atas aspek aritmatika, algoritma angka dan algoritma kata. Hasil penelitian ini menunjukkan bahwa Kemampuan Algoritma kata dalam menyelesaikan persoalan matematika sangat dipengaruhi oleh kemampuan dalam menyelesaikan masalah non verbal (mampu berlogika), kemampuan algoritma angka dan memori jangka panjang (secara langsung maupun tidak langsung) sedangkan aritmatika dan kerja memori berpengaruh secara tidak langsung terhadap kemampuan algoritma kata (menyusun prosedur dalam penyelesaian soal cerita matematika). Dan juga perlu adanya penerapan metode yang menarik yaitu metode tanya jawab supaya mahasiswa lebih aktif dalam mengungkapkan pendapat serta metode permainan matematika yang menggunakan kemampuan berlogika seperti quis-quis (asah otak atau teka-teki) matematika sederhana

Theoretical aspects of the CEBAF 89-009 experiment on inclusive scattering of 4.05 GeV electrons from nuclei

We compare recent CEBAF data on inclusive electron scattering on nuclei with predictions, based on a relation between structure functions (SF) of a nucleus, a nucleon and a nucleus of point-nucleons. The latter contains nuclear dynamics, e.g. binary collision contributions in addition to the asymptotic limit. The agreement with the data is good, except in low-intensity regions. Computed ternary collsion contributions appear too small for an explanation. We perform scaling analyses in Gurvitz's scaling variable and found that for $y_G\gtrless 0$, ratios of scaling functions for pairs of nuclei differ by less than 15-20% from 1. Scaling functions for $0$ are, for increasing $Q^2$, shown to approach a plateau from above. We observe only weak $Q^2$-dependence in FSI, which in the relevant kinematic region is ascribed to the diffractive nature of the NN amplitudes appearing in FSI. This renders it difficult to separate asymptotic from FSI parts and seriously hampers the extraction of $n(p)$ from scaling analyses in a model-independnent fashion.Comment: 11 p. Latex file, 2 ps fig

Supercritical Extraction from Vinification Residues: Fatty Acids, α-Tocopherol, and Phenolic Compounds in the Oil Seeds from Different Varieties of Grape

Supercritical fluid extraction has been widely employed in the extraction of high purity substances. In this study, we used the technology to obtain oil from seeds from a variety of grapes, from vinification residues generated in the Southern region of the state of Rio Grande do Sul, Brazil. This work encompasses three varieties of Vitis vinifera (Moscato Giallo, Merlot, and Cabernet Sauvignon) and two of Vitis labrusca (Bordô e Isabel), harvested in 2005 and 2006. We obtained the highest oil content from Bordô (15.40%) in 2005 and from Merlot (14.66%), 2006. The biggest concentration of palmitic, stearic, and linoleic acids was observed in Bordô, 2005, and in Bordô, Merlot, and Moscato Giallo, 2006. Bordô showed the highest concentration of oleic acid and α-tocopherol in both seasons too. For the equivalent of procyanidins, we did not notice significant difference among the varieties from the 2005 harvest. In 2006, both varieties Isabel and Cabernet Sauvignon showed a value slightly lower than the other varieties. The concentration of total phenolics was higher in Bordô and Cabernet Sauvignon. The presence of these substances is related to several important pharmacological properties and might be an alternative to conventional processes to obtain these bioactives

How Does SARS-CoV-2 Affect the Central Nervous System? A Working Hypothesis

Interstitial pneumonia was the first manifestation to be recognized as caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); however, in just a few weeks, it became clear that the coronavirus disease-2019 (COVID-19) overrun tissues and more body organs than just the lungs, so much so that it could be considered a systemic pathology. Several studies reported the involvement of the conjunctiva, the gut, the heart and its pace, and vascular injuries such as thromboembolic complications and Kawasaki disease in children and toddlers were also described. More recently, it was reported that in a sample of 214 SARS-CoV-2 positive patients, 36.4% complained of neurological symptoms ranging from non-specific manifestations (dizziness, headache, and seizures), to more specific symptoms such hyposmia or hypogeusia, and stroke. Older individuals, especially males with comorbidities, appear to be at the highest risk of developing such severe complications related to the Central Nervous System (CNS) involvement. Neuropsychiatric manifestations in COVID-19 appear to develop in patients with and without pre-existing neurological disorders. Growing evidence suggests that SARS-CoV-2 binds to the human Angiotensin-Converting Enzyme 2 (ACE2) for the attachment and entrance inside host cells. By describing ACE2 and the whole Renin Angiotensin Aldosterone System (RAAS) we may better understand whether specific cell types may be affected by SARS-CoV-2 and whether their functioning can be disrupted in case of an infection. Since clear evidences of neurological interest have already been shown, by clarifying the topographical distribution and density of ACE2, we will be able to speculate how SARS-CoV-2 may affect the CNS and what is the pathogenetic mechanism by which it contributes to the specific clinical manifestations of the disease. Based on such evidences, we finally hypothesize the process of SARS-CoV-2 invasion of the CNS and provide a possible explanation for the onset or the exacerbation of some common neuropsychiatric disorders in the elderly including cognitive impairment and Alzheimer disease

Realistic Model of the Nucleon Spectral Function in Few- and Many- Nucleon Systems

By analysing the high momentum features of the nucleon momentum distribution in light and complex nuclei, it is argued that the basic two-nucleon configurations generating the structure of the nucleon Spectral Function at high values of the nucleon momentum and removal energy, can be properly described by a factorised ansatz for the nuclear wave function, which leads to a nucleon Spectral Function in the form of a convolution integral involving the momentum distributions describing the relative and center-of-mass motion of a correlated nucleon-nucleon pair embedded in the medium. The Spectral Functions of $^3He$ and infinite nuclear matter resulting from the convolution formula and from many-body calculations are compared, and a very good agreement in a wide range of values of nucleon momentum and removal energy is found. Applications of the model to the analysis of inclusive and exclusive processes are presented, illustrating those features of the cross section which are sensitive to that part of the Spectral Function which is governed by short-range and tensor nucleon-nucleon correlations.Comment: 40 pages Latex , 16 ps figures available from the above e-mail address or from [email protected]

Exact 4He Spectral Function in a Semirealistic NN Potential Model

The spectral function of 4He is calculated with the Lorentz integral transform method in a large energy and momentum range. The excitation spectrum of the residual 3N-system is fully taken into account. The obtained spectral function is used to calculate the quasi elastic longitudinal (e,e') response R_l of 4He for q=300, 400, and 500 MeV/c. Comparison with the exact R_l shows a rather sizeable disagreement except in the quasi elastic peak, where the differences reduce to about 10% at q=500 MeV/c. It is shown as well that very simple momentum distribution approximations for the spectral function provide practically the same results for R_l as the exact spectral function.Comment: 7 pages, Latex (Revtex), 4 Postscript figures, to appear in Phys. Rev.